cmd/tailscale/cli: remove special-casing of JS/WASM

We're no longer compiling the entire CLI for WASM, so we can remove
some wrapper functions and GOOS checks.

Effectively reverts 75de4e9cc2.
5df7ac70d6, eda647cb47
and other changes.

Fixes #5146

Signed-off-by: Mihai Parparita <mihai@tailscale.com>

.github/workflows/cifuzz.yml

@@ -19,7 +19,7 @@ jobs:
         dry-run: false
         language: go
     - name: Upload Crash
-      uses: actions/upload-artifact@v2.3.1
+      uses: actions/upload-artifact@v3
       if: failure() && steps.build.outcome == 'success'
       with:
         name: artifacts

.github/workflows/codeql-analysis.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/cross-darwin.yml

@@ -17,13 +17,13 @@ jobs:
     steps:
 
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: macOS build cmd
       env:

.github/workflows/cross-freebsd.yml

@@ -17,13 +17,13 @@ jobs:
     steps:
 
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: FreeBSD build cmd
       env:

.github/workflows/cross-openbsd.yml

@@ -17,13 +17,13 @@ jobs:
     steps:
 
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: OpenBSD build cmd
       env:

.github/workflows/cross-wasm.yml

@@ -0,0 +1,52 @@
+name: Wasm-Cross
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - '*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    if: "!contains(github.event.head_commit.message, '[ci skip]')"
+
+    steps:
+
+    - name: Set up Go
+      uses: actions/setup-go@v3
+      with:
+        go-version: 1.18
+      id: go
+
+    - name: Check out code into the Go module directory
+      uses: actions/checkout@v3
+
+    - name: Wasm client build
+      env:
+        GOOS: js
+        GOARCH: wasm
+      run: go build ./cmd/tsconnect/wasm
+
+    - name: tsconnect static build
+      # Use our custom Go toolchain, we set build tags (to control binary size)
+      # that depend on it.
+      run: ./tool/go run ./cmd/tsconnect build
+
+    - uses: k0kubun/action-slack@v2.0.0
+      with:
+        payload: |
+          {
+            "attachments": [{
+              "text": "${{ job.status }}: ${{ github.workflow }} <https://github.com/${{ github.repository }}/commit/${{ github.sha }}/checks|${{ env.COMMIT_DATE }} #${{ env.COMMIT_NUMBER_OF_DAY }}> " +
+                      "(<https://github.com/${{ github.repository }}/commit/${{ github.sha }}|" + "${{ github.sha }}".substring(0, 10) + ">) " +
+                      "of ${{ github.repository }}@" + "${{ github.ref }}".split('/').reverse()[0] + " by ${{ github.event.head_commit.committer.name }}",
+              "color": "danger"
+            }]
+          }
+      env:
+        SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
+      if: failure() && github.event_name == 'push'

.github/workflows/cross-windows.yml

@@ -17,13 +17,13 @@ jobs:
     steps:
 
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: Windows build cmd
       env:

.github/workflows/depaware.yml

@@ -14,12 +14,12 @@ jobs:
 
     steps:
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
 
     - name: Check out code
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: depaware tailscaled
       run: go run github.com/tailscale/depaware --check tailscale.com/cmd/tailscaled

.github/workflows/go_generate.yml

@@ -15,12 +15,12 @@ jobs:
 
     steps:
       - name: Set up Go
-        uses: actions/setup-go@v2.1.5
+        uses: actions/setup-go@v3
         with:
-          go-version: 1.17
+          go-version: 1.18
 
       - name: Check out code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           fetch-depth: 0
 

.github/workflows/license.yml

@@ -14,12 +14,12 @@ jobs:
 
     steps:
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
 
     - name: Check out code
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: Run license checker
       run: ./scripts/check_license_headers.sh .

.github/workflows/linux-race.yml

@@ -17,13 +17,13 @@ jobs:
     steps:
 
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: Basic build
       run: go build ./cmd/...

.github/workflows/linux.yml

@@ -17,17 +17,22 @@ jobs:
     steps:
 
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: Basic build
       run: go build ./cmd/...
 
+    - name: Build variants
+      run: |
+        go install --tags=ts_include_cli ./cmd/tailscaled
+        go install --tags=ts_omit_aws ./cmd/tailscaled
+
     - name: Get QEMU
       run: |
         # The qemu in Ubuntu 20.04 (Focal) is too old; we need 5.x something

.github/workflows/linux32.yml

@@ -17,13 +17,13 @@ jobs:
     steps:
 
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
       id: go
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
 
     - name: Basic build
       run: GOARCH=386 go build ./cmd/...

.github/workflows/staticcheck.yml

@@ -14,12 +14,15 @@ jobs:
 
     steps:
     - name: Set up Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17
+        go-version: 1.18
 
     - name: Check out code
-      uses: actions/checkout@v1
+      uses: actions/checkout@v3
+
+    - name: Run gofmt (goimports)
+      run: go run golang.org/x/tools/cmd/goimports -d --format-only .
 
     - name: Run go vet
       run: go vet ./...

.github/workflows/vm.yml

@@ -16,12 +16,12 @@ jobs:
         run: echo "GOPATH=$HOME/go" >> $GITHUB_ENV
 
       - name: Set up Go
-        uses: actions/setup-go@v2.1.5
+        uses: actions/setup-go@v3
         with:
-          go-version: 1.17
+          go-version: 1.18
 
       - name: Checkout Code
-        uses: actions/checkout@v1
+        uses: actions/checkout@v3
 
       - name: Run VM tests
         run: go test ./tstest/integration/vms -v -no-s3 -run-vm-tests -run=TestRunUbuntu2004

.github/workflows/windows-race.yml

@@ -17,20 +17,42 @@ jobs:
     steps:
 
     - name: Install Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17.x
+        go-version: 1.18.x
 
     - name: Checkout code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
 
     - name: Restore Cache
-      uses: actions/cache@v2
+      uses: actions/cache@v3
       with:
-        path: ~/go/pkg/mod
-        key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
-        restore-keys: |
-          ${{ runner.os }}-go-
+        # Note: unlike some other setups, this is only grabbing the mod download
+        # cache, rather than the whole mod directory, as the download cache
+        # contains zips that can be unpacked in parallel faster than they can be
+        # fetched and extracted by tar
+        path: |
+          ~/go/pkg/mod/cache
+          ~\AppData\Local\go-build
+
+        # The -2- here should be incremented when the scheme of data to be
+        # cached changes (e.g. path above changes).
+        # The -race- here ensures that non-race builds and race builds do not
+        # overwrite each others cache, as while they share some files, they
+        # differ in most by volume (build cache).
+        # TODO(raggi): add a go version here.
+        key: ${{ runner.os }}-go-2-race-${{ hashFiles('**/go.sum') }}
+
+    - name: Print toolchain details
+      run: gcc -v
+
+    # There is currently an issue in the race detector in Go on Windows when
+    # used with a newer version of GCC.
+    # See https://github.com/tailscale/tailscale/issues/4926.
+    - name: Downgrade MinGW
+      shell: bash
+      run: |
+        choco install mingw --version 10.2.0 --allow-downgrade
 
     - name: Test with -race flag
       # Don't use -bench=. -benchtime=1x.

.github/workflows/windows.yml

@@ -17,20 +17,28 @@ jobs:
     steps:
 
     - name: Install Go
-      uses: actions/setup-go@v2.1.5
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.17.x
+        go-version: 1.18.x
 
     - name: Checkout code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
 
     - name: Restore Cache
-      uses: actions/cache@v2
+      uses: actions/cache@v3
       with:
-        path: ~/go/pkg/mod
-        key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
-        restore-keys: |
-          ${{ runner.os }}-go-
+        # Note: unlike some other setups, this is only grabbing the mod download
+        # cache, rather than the whole mod directory, as the download cache
+        # contains zips that can be unpacked in parallel faster than they can be
+        # fetched and extracted by tar
+        path: |
+          ~/go/pkg/mod/cache
+          ~\AppData\Local\go-build
+
+        # The -2- here should be incremented when the scheme of data to be
+        # cached changes (e.g. path above changes).
+        # TODO(raggi): add a go version here.
+        key: ${{ runner.os }}-go-2-${{ hashFiles('**/go.sum') }}
 
     - name: Test
       # Don't use -bench=. -benchtime=1x.

ALPINE.txt

@@ -0,0 +1 @@
+3.16

Dockerfile

@@ -32,13 +32,25 @@
 #     $ docker exec tailscaled tailscale status
 
 
-FROM golang:1.17-alpine AS build-env
+FROM golang:1.18-alpine AS build-env
 
 WORKDIR /go/src/tailscale
 
 COPY go.mod go.sum ./
 RUN go mod download
 
+# Pre-build some stuff before the following COPY line invalidates the Docker cache.
+RUN go install \
+    github.com/aws/aws-sdk-go-v2/aws \
+    github.com/aws/aws-sdk-go-v2/config \
+    gvisor.dev/gvisor/pkg/tcpip/adapters/gonet \
+    gvisor.dev/gvisor/pkg/tcpip/stack \
+    golang.org/x/crypto/ssh \
+    golang.org/x/crypto/acme \
+    nhooyr.io/websocket \
+    github.com/mdlayher/netlink \
+    golang.zx2c4.com/wireguard/device
+
 COPY . .
 
 # see build_docker.sh
@@ -56,5 +68,8 @@ RUN GOARCH=$TARGETARCH go install -ldflags="\
       -X tailscale.com/version.GitCommit=$VERSION_GIT_HASH" \
       -v ./cmd/tailscale ./cmd/tailscaled
 
-FROM ghcr.io/tailscale/alpine-base:3.14
+FROM alpine:3.16
+RUN apk add --no-cache ca-certificates iptables iproute2 ip6tables
+
 COPY --from=build-env /go/bin/* /usr/local/bin/
+COPY --from=build-env /go/src/tailscale/docs/k8s/run.sh /usr/local/bin/

Dockerfile.base

@@ -2,5 +2,5 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-FROM alpine:3.15
+FROM alpine:3.16
 RUN apk add --no-cache ca-certificates iptables iproute2 ip6tables

Makefile

@@ -6,24 +6,27 @@ usage:
 	echo "See Makefile"
 
 vet:
-	go vet ./...
+	./tool/go vet ./...
+
+tidy:
+	./tool/go mod tidy -compat=1.17
 
 updatedeps:
-	go run github.com/tailscale/depaware --update tailscale.com/cmd/tailscaled
-	go run github.com/tailscale/depaware --update tailscale.com/cmd/tailscale
+	./tool/go run github.com/tailscale/depaware --update tailscale.com/cmd/tailscaled
+	./tool/go run github.com/tailscale/depaware --update tailscale.com/cmd/tailscale
 
 depaware:
-	go run github.com/tailscale/depaware --check tailscale.com/cmd/tailscaled
-	go run github.com/tailscale/depaware --check tailscale.com/cmd/tailscale
+	./tool/go run github.com/tailscale/depaware --check tailscale.com/cmd/tailscaled
+	./tool/go run github.com/tailscale/depaware --check tailscale.com/cmd/tailscale
 
 buildwindows:
-	GOOS=windows GOARCH=amd64 go install tailscale.com/cmd/tailscale tailscale.com/cmd/tailscaled
+	GOOS=windows GOARCH=amd64 ./tool/go install tailscale.com/cmd/tailscale tailscale.com/cmd/tailscaled
 
 build386:
-	GOOS=linux GOARCH=386 go install tailscale.com/cmd/tailscale tailscale.com/cmd/tailscaled
+	GOOS=linux GOARCH=386 ./tool/go install tailscale.com/cmd/tailscale tailscale.com/cmd/tailscaled
 
 buildlinuxarm:
-	GOOS=linux GOARCH=arm go install tailscale.com/cmd/tailscale tailscale.com/cmd/tailscaled
+	GOOS=linux GOARCH=arm ./tool/go install tailscale.com/cmd/tailscale tailscale.com/cmd/tailscaled
 
 buildmultiarchimage:
 	./build_docker.sh
@@ -31,7 +34,7 @@ buildmultiarchimage:
 check: staticcheck vet depaware buildwindows build386 buildlinuxarm
 
 staticcheck:
-	go run honnef.co/go/tools/cmd/staticcheck -- $$(go list ./... | grep -v tempfork)
+	./tool/go run honnef.co/go/tools/cmd/staticcheck -- $$(./tool/go list ./... | grep -v tempfork)
 
 spk:
 	PATH="${PWD}/tool:${PATH}" ./tool/go run github.com/tailscale/tailscale-synology@main -o tailscale.spk --source=. --goarch=${SYNO_ARCH} --dsm-version=${SYNO_DSM}

README.md

@@ -44,7 +44,7 @@ If your distro has conventions that preclude the use of
 distro's way, so that bug reports contain useful version information.
 
 We only guarantee to support the latest Go release and any Go beta or
-release candidate builds (currently Go 1.17) in module mode. It might
+release candidate builds (currently Go 1.18) in module mode. It might
 work in earlier Go versions or in GOPATH mode, but we're making no
 effort to keep those working.
 

VERSION.txt

@@ -1 +1 @@
-1.21.0
+1.29.0

api.md

@@ -15,12 +15,16 @@ Currently based on {some authentication method}. Visit the [admin panel](https:/
     - [POST device routes](#device-routes-post)
   - Authorize machine
     - [POST device authorized](#device-authorized-post)
+  - Tags
+    - [POST device tags](#device-tags-post)
+  - Key
+    - [POST device key](#device-key-post)
 * **[Tailnets](#tailnet)**
   - ACLs
     - [GET tailnet ACL](#tailnet-acl-get)
-    - [POST tailnet ACL](#tailnet-acl-post): set ACL for a tailnet
-    - [POST tailnet ACL preview](#tailnet-acl-preview-post): preview rule matches on an ACL for a resource
-	- [POST tailnet ACL validate](#tailnet-acl-validate-post): run validation tests against the tailnet's existing ACL
+    - [POST tailnet ACL](#tailnet-acl-post)
+    - [POST tailnet ACL preview](#tailnet-acl-preview-post)
+	- [POST tailnet ACL validate](#tailnet-acl-validate-post)
   - [Devices](#tailnet-devices)
     - [GET tailnet devices](#tailnet-devices-get)
   - [Keys](#tailnet-keys)
@@ -38,12 +42,12 @@ Currently based on {some authentication method}. Visit the [admin panel](https:/
 
 ## Device
 <!-- TODO: description about what devices are -->
-Each Tailscale-connected device has a globally-unique identifier number which we refer as the "deviceID" or sometimes, just "id". 
+Each Tailscale-connected device has a globally-unique identifier number which we refer as the "deviceID" or sometimes, just "id".
 You can use the deviceID to specify operations on a specific device, like retrieving its subnet routes.
 
-To find the deviceID of a particular device, you can use the ["GET /devices"](#getdevices) API call and generate a list of devices on your network. 
+To find the deviceID of a particular device, you can use the ["GET /devices"](#getdevices) API call and generate a list of devices on your network.
 Find the device you're looking for and get the "id" field.
-This is your deviceID. 
+This is your deviceID.
 
 <a name=device-get></a>
 
@@ -56,7 +60,7 @@ Use the `fields` query parameter to explicitly indicate which fields are returne
 ##### Parameters
 ##### Query Parameters
 `fields` - Controls which fields will be included in the returned response.
-Currently, supported options are: 
+Currently, supported options are:
 * `all`: returns all fields in the response.
 * `default`: return all fields except:
   * `enabledRoutes`
@@ -68,7 +72,7 @@ If more than one option is indicated, then the union is used.
 For example, for `fields=default,all`, all fields are returned.
 If the `fields` parameter is not provided, then the default option is used.
 
-##### Example 
+##### Example
 ```
 GET /api/v2/device/12345
 curl 'https://api.tailscale.com/api/v2/device/12345?fields=all' \
@@ -98,10 +102,10 @@ Response
   "nodeKey":"nodekey:user1-node-key",
   "blocksIncomingConnections":false,
   "enabledRoutes":[
-    
+
   ],
   "advertisedRoutes":[
-    
+
   ],
   "clientConnectivity": {
     "endpoints":[
@@ -137,7 +141,7 @@ Response
 <a name=device-delete></a>
 
 #### `DELETE /api/v2/device/:deviceID` - deletes the device from its tailnet
-Deletes the provided device from its tailnet. 
+Deletes the provided device from its tailnet.
 The device must belong to the user's tailnet.
 Deleting shared/external devices is not supported.
 Supply the device of interest in the path using its ID.
@@ -155,7 +159,7 @@ curl -X DELETE 'https://api.tailscale.com/api/v2/device/12345' \
 
 Response
 
-If successful, the response should be empty: 
+If successful, the response should be empty:
 ```
 < HTTP/1.1 200 OK
 ...
@@ -163,7 +167,7 @@ If successful, the response should be empty:
 * Closing connection 0
 ```
 
-If the device is not owned by your tailnet: 
+If the device is not owned by your tailnet:
 ```
 < HTTP/1.1 501 Not Implemented
 ...
@@ -268,8 +272,70 @@ curl 'https://api.tailscale.com/api/v2/device/11055/authorized' \
 The response is 2xx on success. The response body is currently an empty JSON
 object.
 
-## Tailnet 
-A tailnet is the name of your Tailscale network. 
+<a name=device-tags-post></a>
+
+#### `POST /api/v2/device/:deviceID/tags` - update tags on a device
+
+Updates the tags set on a device.
+
+##### Parameters
+
+###### POST Body
+
+`tags` - The new list of tags for the device.
+
+```
+{
+  "tags": ["tag:foo", "tag:bar"]
+}
+```
+
+##### Example
+
+```
+curl 'https://api.tailscale.com/api/v2/device/11055/tags' \
+-u "tskey-yourapikey123:" \
+--data-binary '{"tags": ["tag:foo", "tag:bar"]}'
+```
+
+The response is 2xx on success. The response body is currently an empty JSON
+object.
+
+<a name=device-key-post></a>
+
+#### `POST /api/v2/device/:deviceID/key` - update device key
+
+Allows for updating properties on the device key.
+
+##### Parameters
+
+###### POST Body
+
+`keyExpiryDisabled`
+
+- Provide `true` to disable the device's key expiry. The original key expiry time is still maintained. Upon re-enabling, the key will expire at that original time.
+- Provide `false` to enable the device's key expiry. Sets the key to expire at the original expiry time prior to disabling. The key may already have expired. In that case, the device must be re-authenticated.
+- Empty value will not change the key expiry.
+
+```
+{
+  "keyExpiryDisabled": true
+}
+```
+
+##### Example
+
+```
+curl 'https://api.tailscale.com/api/v2/device/11055/key' \
+-u "tskey-yourapikey123:" \
+--data-binary '{"keyExpiryDisabled": true}'
+```
+
+The response is 2xx on success. The response body is currently an empty JSON
+object.
+
+## Tailnet
+A tailnet is the name of your Tailscale network.
 You can find it in the top left corner of the [Admin Panel](https://login.tailscale.com/admin) beside the Tailscale logo.
 
 
@@ -549,7 +615,12 @@ Response:
 
 #### `POST /api/v2/tailnet/:tailnet/acl/validate` - run validation tests against the tailnet's active ACL
 
-Runs the provided ACL tests against the tailnet's existing ACL. This endpoint does not modify the ACL in any way.
+This endpoint works in one of two modes:
+
+1. with a request body that's a JSON array, the body is interpreted as ACL tests to run against the domain's current ACLs.
+2. with a request body that's a JSON object, the body is interpreted as a hypothetical new JSON (HuJSON) body with new ACLs, including any tests.
+
+In either case, this endpoint does not modify the ACL in any way.
 
 ##### Parameters
 
@@ -559,24 +630,39 @@ The POST body should be a JSON formatted array of ACL Tests.
 
 See https://tailscale.com/kb/1018/acls for more information on the format of ACL tests.
 
-##### Example
+##### Example with tests
 ```
 POST /api/v2/tailnet/example.com/acl/validate
 curl 'https://api.tailscale.com/api/v2/tailnet/example.com/acl/validate' \
   -u "tskey-yourapikey123:" \
   --data-binary '
-{
   [
     {"User": "user1@example.com", "Allow": ["example-host-1:22"], "Deny": ["example-host-2:100"]}
-  ]
-}'
+  ]'
+```
+
+##### Example with an ACL body
+```
+POST /api/v2/tailnet/example.com/acl/validate
+curl 'https://api.tailscale.com/api/v2/tailnet/example.com/acl/validate' \
+  -u "tskey-yourapikey123:" \
+  --data-binary '
+  {
+    "ACLs": [
+     { "Action": "accept", "src": ["100.105.106.107"], "dst": ["1.2.3.4:*"] },
+    ],
+    "Tests", [
+      {"src": "100.105.106.107", "allow": ["1.2.3.4:80"]}
+    ],
+  }'
 ```
 
 Response:
-If all the tests pass, the response will be empty, with an http status code of 200.
 
-Failed test error response:
-A 400 http status code and the errors in the response body.  
+The HTTP status code will be 200 if the request was well formed and there were no server errors, even in the case of failing tests or an invalid ACL. Look at the response body to determine whether there was a problem within your ACL or tests.
+
+If there's a problem, the response body will be a JSON object with a non-empty `message` property and optionally additional details in `data`:
+
 ```
 {
   "message":"test(s) failed",
@@ -589,6 +675,8 @@ A 400 http status code and the errors in the response body.
 }
 ```
 
+An empty body or a JSON object with no `message` is returned on success.
+
 <a name=tailnet-devices></a>
 
 ### Devices
@@ -596,7 +684,7 @@ A 400 http status code and the errors in the response body.
 <a name=tailnet-devices-get></a>
 
 #### <a name="getdevices"></a> `GET /api/v2/tailnet/:tailnet/devices` - list the devices for a tailnet
-Lists the devices in a tailnet. 
+Lists the devices in a tailnet.
 Supply the tailnet of interest in the path.
 Use the `fields` query parameter to explicitly indicate which fields are returned.
 
@@ -605,7 +693,7 @@ Use the `fields` query parameter to explicitly indicate which fields are returne
 
 ###### Query Parameters
 `fields` - Controls which fields will be included in the returned response.
-Currently, supported options are: 
+Currently, supported options are:
 * `all`: Returns all fields in the response.
 * `default`: return all fields except:
   * `enabledRoutes`
@@ -625,7 +713,7 @@ curl 'https://api.tailscale.com/api/v2/tailnet/example.com/devices' \
   -u "tskey-yourapikey123:"
 ```
 
-Response 
+Response
 ```
 {
   "devices":[
@@ -727,11 +815,15 @@ Supply the tailnet in the path.
 `capabilities` - A mapping of resources to permissible actions.
 ```
 {
-	"capabilities": {
+  "capabilities": {
     "devices": {
       "create": {
         "reusable": false,
-        "ephemeral": false
+        "ephemeral": false,
+        "preauthorized": false,
+        "tags": [
+          "tag:example"
+        ]
       }
     }
   }
@@ -751,11 +843,13 @@ The full key can no longer be retrieved by the server.
 
 ```
 echo '{
-	"capabilities": {
+  "capabilities": {
     "devices": {
       "create": {
         "reusable": false,
-        "ephemeral": false
+        "ephemeral": false,
+        "preauthorized": false,
+        "tags": [ "tag:example" ]
       }
     }
   }
@@ -771,7 +865,7 @@ Response:
 	"key":          "tskey-k123456CNTRL-abcdefghijklmnopqrstuvwxyz",
 	"created":      "2021-12-09T23:22:39Z",
 	"expires":      "2022-03-09T23:22:39Z",
-	"capabilities": {"devices": {"create": {"reusable": false, "ephemeral": false}}}
+	"capabilities": {"devices": {"create": {"reusable": false, "ephemeral": false, "preauthorized": false, "tags": [ "tag:example" ]}}}
 }
 ```
 
@@ -801,10 +895,22 @@ curl 'https://api.tailscale.com/api/v2/tailnet/example.com/keys/k123456CNTRL' \
 Response:
 ```
 {
-	"id":           "k123456CNTRL",
-	"created":      "2021-12-09T22:13:53Z",
-	"expires":      "2022-03-09T22:13:53Z",
-	"capabilities": {"devices": {"create": {"reusable": false, "ephemeral": false}}}
+  "id": "k123456CNTRL",
+  "created": "2022-05-05T18:55:44Z",
+  "expires": "2022-08-03T18:55:44Z",
+  "capabilities": {
+    "devices": {
+      "create": {
+        "reusable": false,
+        "ephemeral": true,
+        "preauthorized": false,
+        "tags": [
+          "tag:bar",
+          "tag:foo"
+        ]
+      }
+    }
+  }
 }
 ```
 
@@ -835,13 +941,13 @@ curl -X DELETE 'https://api.tailscale.com/api/v2/tailnet/example.com/keys/k12345
 <a name=tailnet-dns-nameservers-get></a>
 
 #### `GET /api/v2/tailnet/:tailnet/dns/nameservers` - list the DNS nameservers for a tailnet
-Lists the DNS nameservers for a tailnet. 
+Lists the DNS nameservers for a tailnet.
 Supply the tailnet of interest in the path.
 
 ##### Parameters
 No parameters.
 
-##### Example 
+##### Example
 
 ```
 GET /api/v2/tailnet/example.com/dns/nameservers
@@ -849,7 +955,7 @@ curl 'https://api.tailscale.com/api/v2/tailnet/example.com/dns/nameservers' \
   -u "tskey-yourapikey123:"
 ```
 
-Response 
+Response
 ```
 {
   "dns": ["8.8.8.8"],
@@ -859,7 +965,7 @@ Response
 <a name=tailnet-dns-nameservers-post></a>
 
 #### `POST /api/v2/tailnet/:tailnet/dns/nameservers` - replaces the list of DNS nameservers for a tailnet
-Replaces the list of DNS nameservers for the given tailnet with the list supplied by the user. 
+Replaces the list of DNS nameservers for the given tailnet with the list supplied by the user.
 Supply the tailnet of interest in the path.
 Note that changing the list of DNS nameservers may also affect the status of MagicDNS (if MagicDNS is on).
 
@@ -873,7 +979,7 @@ Note that changing the list of DNS nameservers may also affect the status of Mag
 ```
 
 ##### Returns
-Returns the new list of nameservers and the status of MagicDNS. 
+Returns the new list of nameservers and the status of MagicDNS.
 
 If all nameservers have been removed, MagicDNS will be automatically disabled (until explicitly turned back on by the user).
 
@@ -917,31 +1023,31 @@ Retrieves the DNS preferences that are currently set for the given tailnet.
 Supply the tailnet of interest in the path.
 
 ##### Parameters
-No parameters. 
+No parameters.
 
 ##### Example
 ```
 GET /api/v2/tailnet/example.com/dns/preferences
 curl 'https://api.tailscale.com/api/v2/tailnet/example.com/dns/preferences' \
-  -u "tskey-yourapikey123:" 
+  -u "tskey-yourapikey123:"
 ```
 
 Response:
 ```
 {
-  "magicDNS":false, 
+  "magicDNS":false,
 }
 ```
 
 <a name=tailnet-dns-preferences-post></a>
 
-#### `POST /api/v2/tailnet/:tailnet/dns/preferences` - replaces the DNS preferences for a tailnet 
+#### `POST /api/v2/tailnet/:tailnet/dns/preferences` - replaces the DNS preferences for a tailnet
 Replaces the DNS preferences for a tailnet, specifically, the MagicDNS setting.
-Note that MagicDNS is dependent on DNS servers. 
+Note that MagicDNS is dependent on DNS servers.
 
-If there is at least one DNS server, then MagicDNS can be enabled. 
+If there is at least one DNS server, then MagicDNS can be enabled.
 Otherwise, it returns an error.
-Note that removing all nameservers will turn off MagicDNS. 
+Note that removing all nameservers will turn off MagicDNS.
 To reenable it, nameservers must be added back, and MagicDNS must be explicitly turned on.
 
 ##### Parameters
@@ -972,7 +1078,7 @@ If there are no DNS servers, it returns an error message:
 }
 ```
 
-If there are DNS servers: 
+If there are DNS servers:
 ```
 {
   "magicDNS":true,
@@ -981,8 +1087,8 @@ If there are DNS servers:
 
 <a name=tailnet-dns-searchpaths-get></a>
 
-#### `GET /api/v2/tailnet/:tailnet/dns/searchpaths` - retrieves the search paths for a tailnet 
-Retrieves the list of search paths that is currently set for the given tailnet. 
+#### `GET /api/v2/tailnet/:tailnet/dns/searchpaths` - retrieves the search paths for a tailnet
+Retrieves the list of search paths that is currently set for the given tailnet.
 Supply the tailnet of interest in the path.
 
 
@@ -993,7 +1099,7 @@ No parameters.
 ```
 GET /api/v2/tailnet/example.com/dns/searchpaths
 curl 'https://api.tailscale.com/api/v2/tailnet/example.com/dns/searchpaths' \
-  -u "tskey-yourapikey123:" 
+  -u "tskey-yourapikey123:"
 ```
 
 Response:
@@ -1005,7 +1111,7 @@ Response:
 
 <a name=tailnet-dns-searchpaths-post></a>
 
-#### `POST /api/v2/tailnet/:tailnet/dns/searchpaths` - replaces the search paths for a tailnet 
+#### `POST /api/v2/tailnet/:tailnet/dns/searchpaths` - replaces the search paths for a tailnet
 Replaces the list of searchpaths with the list supplied by the user and returns an error otherwise.
 
 ##### Parameters
@@ -1014,7 +1120,7 @@ Replaces the list of searchpaths with the list supplied by the user and returns
 `searchPaths` - A list of searchpaths in JSON.
 ```
 {
-  "searchPaths: ["user1.example.com", "user2.example.com"]
+  "searchPaths": ["user1.example.com", "user2.example.com"]
 }
 ```
 

build_dist.sh

@@ -45,4 +45,25 @@ EOF
 	exit 0
 fi
 
-exec ./tool/go build -ldflags "-X tailscale.com/version.Long=${LONG} -X tailscale.com/version.Short=${SHORT} -X tailscale.com/version.GitCommit=${GIT_HASH}" "$@"
+tags=""
+ldflags="-X tailscale.com/version.Long=${LONG} -X tailscale.com/version.Short=${SHORT} -X tailscale.com/version.GitCommit=${GIT_HASH}"
+
+# build_dist.sh arguments must precede go build arguments.
+while [ "$#" -gt 1 ]; do
+	case "$1" in
+	--extra-small)
+		shift
+		ldflags="$ldflags -w -s"
+		tags="${tags:+$tags,}ts_omit_aws"
+		;;
+	--box)
+		shift
+		tags="${tags:+$tags,}ts_include_cli"
+		;;
+	*)
+		break
+		;;
+	esac
+done
+
+exec ./tool/go build ${tags:+-tags=$tags} -ldflags "$ldflags" "$@"

build_docker.sh

@@ -25,14 +25,14 @@ export PATH=$PWD/tool:$PATH
 eval $(./build_dist.sh shellvars)
 DEFAULT_TAGS="v${VERSION_SHORT},v${VERSION_MINOR}"
 DEFAULT_REPOS="tailscale/tailscale,ghcr.io/tailscale/tailscale"
-DEFAULT_BASE="ghcr.io/tailscale/alpine-base:3.14"
+DEFAULT_BASE="ghcr.io/tailscale/alpine-base:3.16"
 
 PUSH="${PUSH:-false}"
 REPOS="${REPOS:-${DEFAULT_REPOS}}"
 TAGS="${TAGS:-${DEFAULT_TAGS}}"
 BASE="${BASE:-${DEFAULT_BASE}}"
 
-go run github.com/tailscale/mkctr@latest \
+go run github.com/tailscale/mkctr \
   --gopaths="\
     tailscale.com/cmd/tailscale:/usr/local/bin/tailscale, \
     tailscale.com/cmd/tailscaled:/usr/local/bin/tailscaled" \
@@ -40,7 +40,9 @@ go run github.com/tailscale/mkctr@latest \
     -X tailscale.com/version.Long=${VERSION_LONG} \
     -X tailscale.com/version.Short=${VERSION_SHORT} \
     -X tailscale.com/version.GitCommit=${VERSION_GIT_HASH}" \
+  --files="docs/k8s/run.sh:/tailscale/run.sh" \
   --base="${BASE}" \
   --tags="${TAGS}" \
   --repos="${REPOS}" \
-  --push="${PUSH}"
+  --push="${PUSH}" \
+  /bin/sh /tailscale/run.sh

chirp/chirp.go

@@ -19,9 +19,9 @@ func New(socket string) (*BIRDClient, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to BIRD: %w", err)
 	}
-	b := &BIRDClient{socket: socket, conn: conn, bs: bufio.NewScanner(conn)}
+	b := &BIRDClient{socket: socket, conn: conn, scanner: bufio.NewScanner(conn)}
 	// Read and discard the first line as that is the welcome message.
-	if _, err := b.readLine(); err != nil {
+	if _, err := b.readResponse(); err != nil {
 		return nil, err
 	}
 	return b, nil
@@ -29,9 +29,9 @@ func New(socket string) (*BIRDClient, error) {
 
 // BIRDClient handles communication with the BIRD Internet Routing Daemon.
 type BIRDClient struct {
-	socket string
-	conn   net.Conn
-	bs     *bufio.Scanner
+	socket  string
+	conn    net.Conn
+	scanner *bufio.Scanner
 }
 
 // Close closes the underlying connection to BIRD.
@@ -39,7 +39,7 @@ func (b *BIRDClient) Close() error { return b.conn.Close() }
 
 // DisableProtocol disables the provided protocol.
 func (b *BIRDClient) DisableProtocol(protocol string) error {
-	out, err := b.exec("disable %s\n", protocol)
+	out, err := b.exec("disable %s", protocol)
 	if err != nil {
 		return err
 	}
@@ -53,7 +53,7 @@ func (b *BIRDClient) DisableProtocol(protocol string) error {
 
 // EnableProtocol enables the provided protocol.
 func (b *BIRDClient) EnableProtocol(protocol string) error {
-	out, err := b.exec("enable %s\n", protocol)
+	out, err := b.exec("enable %s", protocol)
 	if err != nil {
 		return err
 	}
@@ -65,19 +65,65 @@ func (b *BIRDClient) EnableProtocol(protocol string) error {
 	return fmt.Errorf("failed to enable %s: %v", protocol, out)
 }
 
-func (b *BIRDClient) exec(cmd string, args ...interface{}) (string, error) {
+// BIRD CLI docs from https://bird.network.cz/?get_doc&v=20&f=prog-2.html#ss2.9
+
+// Each session of the CLI consists of a sequence of request and replies,
+// slightly resembling the FTP and SMTP protocols.
+// Requests are commands encoded as a single line of text,
+// replies are sequences of lines starting with a four-digit code
+// followed by either a space (if it's the last line of the reply) or
+// a minus sign (when the reply is going to continue with the next line),
+// the rest of the line contains a textual message semantics of which depends on the numeric code.
+// If a reply line has the same code as the previous one and it's a continuation line,
+// the whole prefix can be replaced by a single white space character.
+//
+// Reply codes starting with 0 stand for ‘action successfully completed’ messages,
+// 1 means ‘table entry’, 8 ‘runtime error’ and 9 ‘syntax error’.
+
+func (b *BIRDClient) exec(cmd string, args ...any) (string, error) {
 	if _, err := fmt.Fprintf(b.conn, cmd, args...); err != nil {
 		return "", err
 	}
-	return b.readLine()
+	fmt.Fprintln(b.conn)
+	return b.readResponse()
 }
 
-func (b *BIRDClient) readLine() (string, error) {
-	if !b.bs.Scan() {
-		return "", fmt.Errorf("reading response from bird failed")
+// hasResponseCode reports whether the provided byte slice is
+// prefixed with a BIRD response code.
+// Equivalent regex: `^\d{4}[ -]`.
+func hasResponseCode(s []byte) bool {
+	if len(s) < 5 {
+		return false
 	}
-	if err := b.bs.Err(); err != nil {
-		return "", err
+	for _, b := range s[:4] {
+		if '0' <= b && b <= '9' {
+			continue
+		}
+		return false
 	}
-	return b.bs.Text(), nil
+	return s[4] == ' ' || s[4] == '-'
+}
+
+func (b *BIRDClient) readResponse() (string, error) {
+	var resp strings.Builder
+	var done bool
+	for !done {
+		if !b.scanner.Scan() {
+			return "", fmt.Errorf("reading response from bird failed: %q", resp.String())
+		}
+		if err := b.scanner.Err(); err != nil {
+			return "", err
+		}
+		out := b.scanner.Bytes()
+		if _, err := resp.Write(out); err != nil {
+			return "", err
+		}
+		if hasResponseCode(out) {
+			done = out[4] == ' '
+		}
+		if !done {
+			resp.WriteRune('\n')
+		}
+	}
+	return resp.String(), nil
 }

chirp/chirp_test.go

@@ -0,0 +1,111 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+package chirp
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"net"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+type fakeBIRD struct {
+	net.Listener
+	protocolsEnabled map[string]bool
+	sock             string
+}
+
+func newFakeBIRD(t *testing.T, protocols ...string) *fakeBIRD {
+	sock := filepath.Join(t.TempDir(), "sock")
+	l, err := net.Listen("unix", sock)
+	if err != nil {
+		t.Fatal(err)
+	}
+	pe := make(map[string]bool)
+	for _, p := range protocols {
+		pe[p] = false
+	}
+	return &fakeBIRD{
+		Listener:         l,
+		protocolsEnabled: pe,
+		sock:             sock,
+	}
+}
+
+func (fb *fakeBIRD) listen() error {
+	for {
+		c, err := fb.Accept()
+		if err != nil {
+			if errors.Is(err, net.ErrClosed) {
+				return nil
+			}
+			return err
+		}
+		go fb.handle(c)
+	}
+}
+
+func (fb *fakeBIRD) handle(c net.Conn) {
+	fmt.Fprintln(c, "0001 BIRD 2.0.8 ready.")
+	sc := bufio.NewScanner(c)
+	for sc.Scan() {
+		cmd := sc.Text()
+		args := strings.Split(cmd, " ")
+		switch args[0] {
+		case "enable":
+			en, ok := fb.protocolsEnabled[args[1]]
+			if !ok {
+				fmt.Fprintln(c, "9001 syntax error, unexpected CF_SYM_UNDEFINED, expecting CF_SYM_KNOWN or TEXT or ALL")
+			} else if en {
+				fmt.Fprintf(c, "0010-%s: already enabled\n", args[1])
+			} else {
+				fmt.Fprintf(c, "0011-%s: enabled\n", args[1])
+			}
+			fmt.Fprintln(c, "0000 ")
+			fb.protocolsEnabled[args[1]] = true
+		case "disable":
+			en, ok := fb.protocolsEnabled[args[1]]
+			if !ok {
+				fmt.Fprintln(c, "9001 syntax error, unexpected CF_SYM_UNDEFINED, expecting CF_SYM_KNOWN or TEXT or ALL")
+			} else if !en {
+				fmt.Fprintf(c, "0008-%s: already disabled\n", args[1])
+			} else {
+				fmt.Fprintf(c, "0009-%s: disabled\n", args[1])
+			}
+			fmt.Fprintln(c, "0000 ")
+			fb.protocolsEnabled[args[1]] = false
+		}
+	}
+}
+
+func TestChirp(t *testing.T) {
+	fb := newFakeBIRD(t, "tailscale")
+	defer fb.Close()
+	go fb.listen()
+	c, err := New(fb.sock)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := c.EnableProtocol("tailscale"); err != nil {
+		t.Fatal(err)
+	}
+	if err := c.EnableProtocol("tailscale"); err != nil {
+		t.Fatal(err)
+	}
+	if err := c.DisableProtocol("tailscale"); err != nil {
+		t.Fatal(err)
+	}
+	if err := c.DisableProtocol("tailscale"); err != nil {
+		t.Fatal(err)
+	}
+	if err := c.EnableProtocol("rando"); err == nil {
+		t.Fatalf("enabling %q succeded", "rando")
+	}
+	if err := c.DisableProtocol("rando"); err == nil {
+		t.Fatalf("disabling %q succeded", "rando")
+	}
+}

client/tailscale/acl.go

@@ -0,0 +1,477 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+// +build go1.18
+
+package tailscale
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/netip"
+)
+
+// ACLRow defines a rule that grants access by a set of users or groups to a set
+// of servers and ports.
+// Only one of Src/Dst or Users/Ports may be specified.
+type ACLRow struct {
+	Action string   `json:"action,omitempty"` // valid values: "accept"
+	Users  []string `json:"users,omitempty"`  // old name for src
+	Ports  []string `json:"ports,omitempty"`  // old name for dst
+	Src    []string `json:"src,omitempty"`
+	Dst    []string `json:"dst,omitempty"`
+}
+
+// ACLTest defines a test for your ACLs to prevent accidental exposure or
+// revoking of access to key servers and ports. Only one of Src or User may be
+// specified, and only one of Allow/Accept may be specified.
+type ACLTest struct {
+	Src    string   `json:"src,omitempty"`    // source
+	User   string   `json:"user,omitempty"`   // old name for source
+	Accept []string `json:"accept,omitempty"` // expected destination ip:port that user can access
+	Deny   []string `json:"deny,omitempty"`   // expected destination ip:port that user cannot access
+
+	Allow []string `json:"allow,omitempty"` // old name for accept
+}
+
+// ACLDetails contains all the details for an ACL.
+type ACLDetails struct {
+	Tests     []ACLTest           `json:"tests,omitempty"`
+	ACLs      []ACLRow            `json:"acls,omitempty"`
+	Groups    map[string][]string `json:"groups,omitempty"`
+	TagOwners map[string][]string `json:"tagowners,omitempty"`
+	Hosts     map[string]string   `json:"hosts,omitempty"`
+}
+
+// ACL contains an ACLDetails and metadata.
+type ACL struct {
+	ACL  ACLDetails
+	ETag string // to check with version on server
+}
+
+// ACLHuJSON contains the HuJSON string of the ACL and metadata.
+type ACLHuJSON struct {
+	ACL      string
+	Warnings []string
+	ETag     string // to check with version on server
+}
+
+// ACL makes a call to the Tailscale server to get a JSON-parsed version of the ACL.
+// The JSON-parsed version of the ACL contains no comments as proper JSON does not support
+// comments.
+func (c *Client) ACL(ctx context.Context) (acl *ACL, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.ACL: %w", err)
+		}
+	}()
+
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl", c.baseURL(), c.tailnet)
+	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Accept", "application/json")
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	// Otherwise, try to decode the response.
+	var aclDetails ACLDetails
+	if err = json.Unmarshal(b, &aclDetails); err != nil {
+		return nil, err
+	}
+	acl = &ACL{
+		ACL:  aclDetails,
+		ETag: resp.Header.Get("ETag"),
+	}
+	return acl, nil
+}
+
+// ACLHuJSON makes a call to the Tailscale server to get the ACL HuJSON and returns
+// it as a string.
+// HuJSON is JSON with a few modifications to make it more human-friendly. The primary
+// changes are allowing comments and trailing comments. See the following links for more info:
+// https://tailscale.com/kb/1018/acls?q=acl#tailscale-acl-policy-format
+// https://github.com/tailscale/hujson
+func (c *Client) ACLHuJSON(ctx context.Context) (acl *ACLHuJSON, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.ACLHuJSON: %w", err)
+		}
+	}()
+
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl?details=1", c.baseURL(), c.tailnet)
+	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Accept", "application/hujson")
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	data := struct {
+		ACL      []byte   `json:"acl"`
+		Warnings []string `json:"warnings"`
+	}{}
+	if err := json.Unmarshal(b, &data); err != nil {
+		return nil, err
+	}
+
+	acl = &ACLHuJSON{
+		ACL:      string(data.ACL),
+		Warnings: data.Warnings,
+		ETag:     resp.Header.Get("ETag"),
+	}
+	return acl, nil
+}
+
+// ACLTestFailureSummary specifies a user for which ACL tests
+// failed and the related user-friendly error messages.
+//
+// ACLTestFailureSummary specifies the JSON format sent to the
+// JavaScript client to be rendered in the HTML.
+type ACLTestFailureSummary struct {
+	User   string   `json:"user"`
+	Errors []string `json:"errors"`
+}
+
+// ACLTestError is ErrResponse but with an extra field to account for ACLTestFailureSummary.
+type ACLTestError struct {
+	ErrResponse
+	Data []ACLTestFailureSummary `json:"data"`
+}
+
+func (e ACLTestError) Error() string {
+	return fmt.Sprintf("%s, Data: %+v", e.ErrResponse.Error(), e.Data)
+}
+
+func (c *Client) aclPOSTRequest(ctx context.Context, body []byte, avoidCollisions bool, etag, acceptHeader string) ([]byte, string, error) {
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl", c.baseURL(), c.tailnet)
+	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(body))
+	if err != nil {
+		return nil, "", err
+	}
+
+	if avoidCollisions {
+		req.Header.Set("If-Match", etag)
+	}
+	req.Header.Set("Accept", acceptHeader)
+	req.Header.Set("Content-Type", "application/hujson")
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, "", err
+	}
+
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		// check if test error
+		var ate ACLTestError
+		if err := json.Unmarshal(b, &ate); err != nil {
+			return nil, "", err
+		}
+		ate.Status = resp.StatusCode
+		return nil, "", ate
+	}
+	return b, resp.Header.Get("ETag"), nil
+}
+
+// SetACL sends a POST request to update the ACL according to the provided ACL object. If
+// `avoidCollisions` is true, it will use the ETag obtained in the GET request in an If-Match
+// header to check if the previously obtained ACL was the latest version and that no updates
+// were missed.
+//
+// Returns error with status code 412 if mistmached ETag and avoidCollisions is set to true.
+// Returns error if ACL has tests that fail.
+// Returns error if there are other errors with the ACL.
+func (c *Client) SetACL(ctx context.Context, acl ACL, avoidCollisions bool) (res *ACL, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SetACL: %w", err)
+		}
+	}()
+	postData, err := json.Marshal(acl.ACL)
+	if err != nil {
+		return nil, err
+	}
+	b, etag, err := c.aclPOSTRequest(ctx, postData, avoidCollisions, acl.ETag, "application/json")
+	if err != nil {
+		return nil, err
+	}
+
+	// Otherwise, try to decode the response.
+	var aclDetails ACLDetails
+	if err = json.Unmarshal(b, &aclDetails); err != nil {
+		return nil, err
+	}
+	res = &ACL{
+		ACL:  aclDetails,
+		ETag: etag,
+	}
+	return res, nil
+}
+
+// SetACLHuJSON sends a POST request to update the ACL according to the provided ACL object. If
+// `avoidCollisions` is true, it will use the ETag obtained in the GET request in an If-Match
+// header to check if the previously obtained ACL was the latest version and that no updates
+// were missed.
+//
+// Returns error with status code 412 if mistmached ETag and avoidCollisions is set to true.
+// Returns error if the HuJSON is invalid.
+// Returns error if ACL has tests that fail.
+// Returns error if there are other errors with the ACL.
+func (c *Client) SetACLHuJSON(ctx context.Context, acl ACLHuJSON, avoidCollisions bool) (res *ACLHuJSON, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SetACLHuJSON: %w", err)
+		}
+	}()
+
+	postData := []byte(acl.ACL)
+	b, etag, err := c.aclPOSTRequest(ctx, postData, avoidCollisions, acl.ETag, "application/hujson")
+	if err != nil {
+		return nil, err
+	}
+
+	res = &ACLHuJSON{
+		ACL:  string(b),
+		ETag: etag,
+	}
+	return res, nil
+}
+
+// UserRuleMatch specifies the source users/groups/hosts that a rule targets
+// and the destination ports that they can access.
+// LineNumber is only useful for requests provided in HuJSON form.
+// While JSON requests will have LineNumber, the value is not useful.
+type UserRuleMatch struct {
+	Users      []string `json:"users"`
+	Ports      []string `json:"ports"`
+	LineNumber int      `json:"lineNumber"`
+}
+
+// ACLPreviewResponse is the response type of previewACLPostRequest
+type ACLPreviewResponse struct {
+	Matches    []UserRuleMatch `json:"matches"`    // ACL rules that match the specified user or ipport.
+	Type       string          `json:"type"`       // The request type: currently only "user" or "ipport".
+	PreviewFor string          `json:"previewFor"` // A specific user or ipport.
+}
+
+// ACLPreview is the response type of PreviewACLForUser, PreviewACLForIPPort, PreviewACLHuJSONForUser, and PreviewACLHuJSONForIPPort
+type ACLPreview struct {
+	Matches []UserRuleMatch `json:"matches"`
+	User    string          `json:"user,omitempty"`   // Filled if response of PreviewACLForUser or PreviewACLHuJSONForUser
+	IPPort  string          `json:"ipport,omitempty"` // Filled if response of PreviewACLForIPPort or PreviewACLHuJSONForIPPort
+}
+
+func (c *Client) previewACLPostRequest(ctx context.Context, body []byte, previewType string, previewFor string) (res *ACLPreviewResponse, err error) {
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl/preview", c.baseURL(), c.tailnet)
+	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(body))
+	if err != nil {
+		return nil, err
+	}
+
+	q := req.URL.Query()
+	q.Add("type", previewType)
+	q.Add("previewFor", previewFor)
+	req.URL.RawQuery = q.Encode()
+
+	req.Header.Set("Content-Type", "application/hujson")
+	c.setAuth(req)
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+	if err = json.Unmarshal(b, &res); err != nil {
+		return nil, err
+	}
+
+	return res, nil
+}
+
+// PreviewACLForUser determines what rules match a given ACL for a user.
+// The ACL can be a locally modified or clean ACL obtained from server.
+//
+// Returns ACLPreview on success with matches in a slice. If there are no matches,
+// the call is still successful but Matches will be an empty slice.
+// Returns error if the provided ACL is invalid.
+func (c *Client) PreviewACLForUser(ctx context.Context, acl ACL, user string) (res *ACLPreview, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.PreviewACLForUser: %w", err)
+		}
+	}()
+	postData, err := json.Marshal(acl.ACL)
+	if err != nil {
+		return nil, err
+	}
+	b, err := c.previewACLPostRequest(ctx, postData, "user", user)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ACLPreview{
+		Matches: b.Matches,
+		User:    b.PreviewFor,
+	}, nil
+}
+
+// PreviewACLForIPPort determines what rules match a given ACL for a ipport.
+// The ACL can be a locally modified or clean ACL obtained from server.
+//
+// Returns ACLPreview on success with matches in a slice. If there are no matches,
+// the call is still successful but Matches will be an empty slice.
+// Returns error if the provided ACL is invalid.
+func (c *Client) PreviewACLForIPPort(ctx context.Context, acl ACL, ipport netip.AddrPort) (res *ACLPreview, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.PreviewACLForIPPort: %w", err)
+		}
+	}()
+	postData, err := json.Marshal(acl.ACL)
+	if err != nil {
+		return nil, err
+	}
+	b, err := c.previewACLPostRequest(ctx, postData, "ipport", ipport.String())
+	if err != nil {
+		return nil, err
+	}
+
+	return &ACLPreview{
+		Matches: b.Matches,
+		IPPort:  b.PreviewFor,
+	}, nil
+}
+
+// PreviewACLHuJSONForUser determines what rules match a given ACL for a user.
+// The ACL can be a locally modified or clean ACL obtained from server.
+//
+// Returns ACLPreview on success with matches in a slice. If there are no matches,
+// the call is still successful but Matches will be an empty slice.
+// Returns error if the provided ACL is invalid.
+func (c *Client) PreviewACLHuJSONForUser(ctx context.Context, acl ACLHuJSON, user string) (res *ACLPreview, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.PreviewACLHuJSONForUser: %w", err)
+		}
+	}()
+	postData := []byte(acl.ACL)
+	b, err := c.previewACLPostRequest(ctx, postData, "user", user)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ACLPreview{
+		Matches: b.Matches,
+		User:    b.PreviewFor,
+	}, nil
+}
+
+// PreviewACLHuJSONForIPPort determines what rules match a given ACL for a ipport.
+// The ACL can be a locally modified or clean ACL obtained from server.
+//
+// Returns ACLPreview on success with matches in a slice. If there are no matches,
+// the call is still successful but Matches will be an empty slice.
+// Returns error if the provided ACL is invalid.
+func (c *Client) PreviewACLHuJSONForIPPort(ctx context.Context, acl ACLHuJSON, ipport string) (res *ACLPreview, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.PreviewACLHuJSONForIPPort: %w", err)
+		}
+	}()
+	postData := []byte(acl.ACL)
+	b, err := c.previewACLPostRequest(ctx, postData, "ipport", ipport)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ACLPreview{
+		Matches: b.Matches,
+		IPPort:  b.PreviewFor,
+	}, nil
+}
+
+// ValidateACLJSON takes in the given source and destination (in this situation,
+// it is assumed that you are checking whether the source can connect to destination)
+// and creates an ACLTest from that. It then sends the ACLTest to the control api acl
+// validate endpoint, where the test is run. It returns a nil ACLTestError pointer if
+// no test errors occur.
+func (c *Client) ValidateACLJSON(ctx context.Context, source, dest string) (testErr *ACLTestError, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.ValidateACLJSON: %w", err)
+		}
+	}()
+
+	tests := []ACLTest{ACLTest{User: source, Allow: []string{dest}}}
+	postData, err := json.Marshal(tests)
+	if err != nil {
+		return nil, err
+	}
+
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl/validate", c.baseURL(), c.tailnet)
+	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(postData))
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	c.setAuth(req)
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("control api responsed with %d status code", resp.StatusCode)
+	}
+
+	// The test ran without fail
+	if len(b) == 0 {
+		return nil, nil
+	}
+
+	var res ACLTestError
+	// The test returned errors.
+	if err = json.Unmarshal(b, &res); err != nil {
+		// failed to unmarshal
+		return nil, err
+	}
+	return &res, nil
+}

client/tailscale/apitype/apitype.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package apitype contains types for the Tailscale local API.
+// Package apitype contains types for the Tailscale local API and control plane API.
 package apitype
 
 import "tailscale.com/tailcfg"
@@ -11,6 +11,9 @@ import "tailscale.com/tailcfg"
 type WhoIsResponse struct {
 	Node        *tailcfg.Node
 	UserProfile *tailcfg.UserProfile
+
+	// Caps are extra capabilities that the remote Node has to this node.
+	Caps []string `json:",omitempty"`
 }
 
 // FileTarget is a node to which files can be sent, and the PeerAPI

client/tailscale/apitype/controltype.go

@@ -0,0 +1,20 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package apitype
+
+type DNSConfig struct {
+	Resolvers         []DNSResolver            `json:"resolvers"`
+	FallbackResolvers []DNSResolver            `json:"fallbackResolvers"`
+	Routes            map[string][]DNSResolver `json:"routes"`
+	Domains           []string                 `json:"domains"`
+	Nameservers       []string                 `json:"nameservers"`
+	Proxied           bool                     `json:"proxied"`
+	PerDomain         bool                     `json:",omitempty"`
+}
+
+type DNSResolver struct {
+	Addr                string   `json:"addr"`
+	BootstrapResolution []string `json:"bootstrapResolution,omitempty"`
+}

client/tailscale/devices.go

@@ -0,0 +1,262 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+// +build go1.18
+
+package tailscale
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"tailscale.com/types/opt"
+)
+
+type GetDevicesResponse struct {
+	Devices []*Device `json:"devices"`
+}
+
+type DerpRegion struct {
+	Preferred           bool    `json:"preferred,omitempty"`
+	LatencyMilliseconds float64 `json:"latencyMs"`
+}
+
+type ClientConnectivity struct {
+	Endpoints             []string `json:"endpoints"`
+	DERP                  string   `json:"derp"`
+	MappingVariesByDestIP opt.Bool `json:"mappingVariesByDestIP"`
+	// DERPLatency is mapped by region name (e.g. "New York City", "Seattle").
+	DERPLatency    map[string]DerpRegion `json:"latency"`
+	ClientSupports map[string]opt.Bool   `json:"clientSupports"`
+}
+
+type Device struct {
+	// Addresses is a list of the devices's Tailscale IP addresses.
+	// It's currently just 1 element, the 100.x.y.z Tailscale IP.
+	Addresses []string `json:"addresses"`
+	DeviceID  string   `json:"id"`
+	User      string   `json:"user"`
+	Name      string   `json:"name"`
+	Hostname  string   `json:"hostname"`
+
+	ClientVersion     string `json:"clientVersion"`   // Empty for external devices.
+	UpdateAvailable   bool   `json:"updateAvailable"` // Empty for external devices.
+	OS                string `json:"os"`
+	Created           string `json:"created"` // Empty for external devices.
+	LastSeen          string `json:"lastSeen"`
+	KeyExpiryDisabled bool   `json:"keyExpiryDisabled"`
+	Expires           string `json:"expires"`
+	Authorized        bool   `json:"authorized"`
+	IsExternal        bool   `json:"isExternal"`
+	MachineKey        string `json:"machineKey"` // Empty for external devices.
+	NodeKey           string `json:"nodeKey"`
+
+	// BlocksIncomingConnections is configured via the device's
+	// Tailscale client preferences. This field is only reported
+	// to the API starting with Tailscale 1.3.x clients.
+	BlocksIncomingConnections bool `json:"blocksIncomingConnections"`
+
+	// The following fields are not included by default:
+
+	// EnabledRoutes are the previously-approved subnet routes
+	// (e.g. "192.168.4.16/24", "10.5.2.4/32").
+	EnabledRoutes []string `json:"enabledRoutes"` // Empty for external devices.
+	// AdvertisedRoutes are the subnets (both enabled and not enabled)
+	// being requested from the node.
+	AdvertisedRoutes []string `json:"advertisedRoutes"` // Empty for external devices.
+
+	ClientConnectivity *ClientConnectivity `json:"clientConnectivity"`
+}
+
+// DeviceFieldsOpts determines which fields should be returned in the response.
+//
+// Please only use DeviceAllFields and DeviceDefaultFields.
+// Other DeviceFieldsOpts are not supported.
+//
+// TODO: Support other DeviceFieldsOpts.
+// In the future, users should be able to create their own DeviceFieldsOpts
+// as valid arguments by setting the fields they want returned to a "non-nil"
+// value. For example, DeviceFieldsOpts{NodeID: "true"} should only return NodeIDs.
+type DeviceFieldsOpts Device
+
+func (d *DeviceFieldsOpts) addFieldsToQueryParameter() string {
+	if d == DeviceDefaultFields || d == nil {
+		return "default"
+	}
+	if d == DeviceAllFields {
+		return "all"
+	}
+
+	return ""
+}
+
+var (
+	DeviceAllFields = &DeviceFieldsOpts{}
+
+	// DeviceDefaultFields specifies that the following fields are returned:
+	//   Addresses, NodeID, User, Name, Hostname, ClientVersion, UpdateAvailable,
+	//   OS, Created, LastSeen, KeyExpiryDisabled, Expires, Authorized, IsExternal
+	//   MachineKey, NodeKey, BlocksIncomingConnections.
+	DeviceDefaultFields = &DeviceFieldsOpts{}
+)
+
+// Devices retrieves the list of devices for a tailnet.
+//
+// See the Device structure for the list of fields hidden for external devices.
+// The optional fields parameter specifies which fields of the devices to return; currently
+// only DeviceDefaultFields (equivalent to nil) and DeviceAllFields are supported.
+// Other values are currently undefined.
+func (c *Client) Devices(ctx context.Context, fields *DeviceFieldsOpts) (deviceList []*Device, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.Devices: %w", err)
+		}
+	}()
+
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/devices", c.baseURL(), c.tailnet)
+	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
+	if err != nil {
+		return nil, err
+	}
+	// Add fields.
+	fieldStr := fields.addFieldsToQueryParameter()
+	q := req.URL.Query()
+	q.Add("fields", fieldStr)
+	req.URL.RawQuery = q.Encode()
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	var devices GetDevicesResponse
+	err = json.Unmarshal(b, &devices)
+	return devices.Devices, err
+}
+
+// Device retrieved the details for a specific device.
+//
+// See the Device structure for the list of fields hidden for an external device.
+// The optional fields parameter specifies which fields of the devices to return; currently
+// only DeviceDefaultFields (equivalent to nil) and DeviceAllFields are supported.
+// Other values are currently undefined.
+func (c *Client) Device(ctx context.Context, deviceID string, fields *DeviceFieldsOpts) (device *Device, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.Device: %w", err)
+		}
+	}()
+	path := fmt.Sprintf("%s/api/v2/device/%s", c.baseURL(), deviceID)
+	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	// Add fields.
+	fieldStr := fields.addFieldsToQueryParameter()
+	q := req.URL.Query()
+	q.Add("fields", fieldStr)
+	req.URL.RawQuery = q.Encode()
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	err = json.Unmarshal(b, &device)
+	return device, err
+}
+
+// DeleteDevice deletes the specified device from the Client's tailnet.
+// NOTE: Only devices that belong to the Client's tailnet can be deleted.
+// Deleting external devices is not supported.
+func (c *Client) DeleteDevice(ctx context.Context, deviceID string) (err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.DeleteDevice: %w", err)
+		}
+	}()
+
+	path := fmt.Sprintf("%s/api/v2/device/%s", c.baseURL(), url.PathEscape(deviceID))
+	req, err := http.NewRequestWithContext(ctx, "DELETE", path, nil)
+	if err != nil {
+		return err
+	}
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return handleErrorResponse(b, resp)
+	}
+	return nil
+}
+
+// AuthorizeDevice marks a device as authorized.
+func (c *Client) AuthorizeDevice(ctx context.Context, deviceID string) error {
+	path := fmt.Sprintf("%s/api/v2/device/%s/authorized", c.baseURL(), url.PathEscape(deviceID))
+	req, err := http.NewRequestWithContext(ctx, "POST", path, strings.NewReader(`{"authorized":true}`))
+	if err != nil {
+		return err
+	}
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return handleErrorResponse(b, resp)
+	}
+
+	return nil
+}
+
+// SetTags updates the ACL tags on a device.
+func (c *Client) SetTags(ctx context.Context, deviceID string, tags []string) error {
+	params := &struct {
+		Tags []string `json:"tags"`
+	}{Tags: tags}
+	data, err := json.Marshal(params)
+	if err != nil {
+		return err
+	}
+	path := fmt.Sprintf("%s/api/v2/device/%s/tags", c.baseURL(), url.PathEscape(deviceID))
+	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(data))
+	if err != nil {
+		return err
+	}
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return handleErrorResponse(b, resp)
+	}
+
+	return nil
+}

client/tailscale/dns.go

@@ -0,0 +1,235 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+// +build go1.18
+
+package tailscale
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"tailscale.com/client/tailscale/apitype"
+)
+
+// DNSNameServers is returned when retrieving the list of nameservers.
+// It is also the structure provided when setting nameservers.
+type DNSNameServers struct {
+	DNS []string `json:"dns"` // DNS name servers
+}
+
+// DNSNameServersPostResponse is returned when setting the list of DNS nameservers.
+//
+// It includes the MagicDNS status since nameservers changes may affect MagicDNS.
+type DNSNameServersPostResponse struct {
+	DNS      []string `json:"dns"`      // DNS name servers
+	MagicDNS bool     `json:"magicDNS"` // whether MagicDNS is active for this tailnet (enabled + has fallback nameservers)
+}
+
+// DNSSearchpaths is the list of search paths for a given domain.
+type DNSSearchPaths struct {
+	SearchPaths []string `json:"searchPaths"` // DNS search paths
+}
+
+// DNSPreferences is the preferences set for a given tailnet.
+//
+// It includes MagicDNS which can be turned on or off. To enable MagicDNS,
+// there must be at least one nameserver. When all nameservers are removed,
+// MagicDNS is disabled.
+type DNSPreferences struct {
+	MagicDNS bool `json:"magicDNS"` // whether MagicDNS is active for this tailnet (enabled + has fallback nameservers)
+}
+
+func (c *Client) dnsGETRequest(ctx context.Context, endpoint string) ([]byte, error) {
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/dns/%s", c.baseURL(), c.tailnet, endpoint)
+	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
+	if err != nil {
+		return nil, err
+	}
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	return b, nil
+}
+
+func (c *Client) dnsPOSTRequest(ctx context.Context, endpoint string, postData interface{}) ([]byte, error) {
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/dns/%s", c.baseURL(), c.tailnet, endpoint)
+	data, err := json.Marshal(&postData)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(data))
+	req.Header.Set("Content-Type", "application/json")
+	if err != nil {
+		return nil, err
+	}
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	return b, nil
+}
+
+// DNSConfig retrieves the DNSConfig settings for a domain.
+func (c *Client) DNSConfig(ctx context.Context) (cfg *apitype.DNSConfig, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.DNSConfig: %w", err)
+		}
+	}()
+	b, err := c.dnsGETRequest(ctx, "config")
+	if err != nil {
+		return nil, err
+	}
+	var dnsResp apitype.DNSConfig
+	err = json.Unmarshal(b, &dnsResp)
+	return &dnsResp, err
+}
+
+func (c *Client) SetDNSConfig(ctx context.Context, cfg apitype.DNSConfig) (resp *apitype.DNSConfig, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SetDNSConfig: %w", err)
+		}
+	}()
+	var dnsResp apitype.DNSConfig
+	b, err := c.dnsPOSTRequest(ctx, "config", cfg)
+	if err != nil {
+		return nil, err
+	}
+	err = json.Unmarshal(b, &dnsResp)
+	return &dnsResp, err
+}
+
+// NameServers retrieves the list of nameservers set for a domain.
+func (c *Client) NameServers(ctx context.Context) (nameservers []string, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.NameServers: %w", err)
+		}
+	}()
+	b, err := c.dnsGETRequest(ctx, "nameservers")
+	if err != nil {
+		return nil, err
+	}
+	var dnsResp DNSNameServers
+	err = json.Unmarshal(b, &dnsResp)
+	return dnsResp.DNS, err
+}
+
+// SetNameServers sets the list of nameservers for a tailnet to the list provided
+// by the user.
+//
+// It returns the new list of nameservers and the MagicDNS status in case it was
+// affected by the change. For example, removing all nameservers will turn off
+// MagicDNS.
+func (c *Client) SetNameServers(ctx context.Context, nameservers []string) (dnsResp *DNSNameServersPostResponse, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SetNameServers: %w", err)
+		}
+	}()
+	dnsReq := DNSNameServers{DNS: nameservers}
+	b, err := c.dnsPOSTRequest(ctx, "nameservers", dnsReq)
+	if err != nil {
+		return nil, err
+	}
+	err = json.Unmarshal(b, &dnsResp)
+	return dnsResp, err
+}
+
+// DNSPreferences retrieves the DNS preferences set for a tailnet.
+//
+// It returns the status of MagicDNS.
+func (c *Client) DNSPreferences(ctx context.Context) (dnsResp *DNSPreferences, err error) {
+	// Format return errors to be descriptive.
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.DNSPreferences: %w", err)
+		}
+	}()
+	b, err := c.dnsGETRequest(ctx, "preferences")
+	if err != nil {
+		return nil, err
+	}
+	err = json.Unmarshal(b, &dnsResp)
+	return dnsResp, err
+}
+
+// SetDNSPreferences sets the DNS preferences for a tailnet.
+//
+// MagicDNS can only be enabled when there is at least one nameserver provided.
+// When all nameservers are removed, MagicDNS is disabled and will stay disabled,
+// unless explicitly enabled by a user again.
+func (c *Client) SetDNSPreferences(ctx context.Context, magicDNS bool) (dnsResp *DNSPreferences, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SetDNSPreferences: %w", err)
+		}
+	}()
+	dnsReq := DNSPreferences{MagicDNS: magicDNS}
+	b, err := c.dnsPOSTRequest(ctx, "preferences", dnsReq)
+	if err != nil {
+		return
+	}
+	err = json.Unmarshal(b, &dnsResp)
+	return dnsResp, err
+}
+
+// SearchPaths retrieves the list of searchpaths set for a tailnet.
+func (c *Client) SearchPaths(ctx context.Context) (searchpaths []string, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SearchPaths: %w", err)
+		}
+	}()
+	b, err := c.dnsGETRequest(ctx, "searchpaths")
+	if err != nil {
+		return nil, err
+	}
+	var dnsResp *DNSSearchPaths
+	err = json.Unmarshal(b, &dnsResp)
+	return dnsResp.SearchPaths, err
+}
+
+// SetSearchPaths sets the list of searchpaths for a tailnet.
+func (c *Client) SetSearchPaths(ctx context.Context, searchpaths []string) (newSearchPaths []string, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SetSearchPaths: %w", err)
+		}
+	}()
+	dnsReq := DNSSearchPaths{SearchPaths: searchpaths}
+	b, err := c.dnsPOSTRequest(ctx, "searchpaths", dnsReq)
+	if err != nil {
+		return nil, err
+	}
+	var dnsResp DNSSearchPaths
+	err = json.Unmarshal(b, &dnsResp)
+	return dnsResp.SearchPaths, err
+}

client/tailscale/localclient.go

@@ -0,0 +1,711 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+// +build go1.18
+
+package tailscale
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/http/httptrace"
+	"net/netip"
+	"net/url"
+	"os/exec"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"go4.org/mem"
+	"tailscale.com/client/tailscale/apitype"
+	"tailscale.com/ipn"
+	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/net/netutil"
+	"tailscale.com/paths"
+	"tailscale.com/safesocket"
+	"tailscale.com/tailcfg"
+)
+
+// defaultLocalClient is the default LocalClient when using the legacy
+// package-level functions.
+var defaultLocalClient LocalClient
+
+// LocalClient is a client to Tailscale's "local API", communicating with the
+// Tailscale daemon on the local machine. Its API is not necessarily stable and
+// subject to changes between releases. Some API calls have stricter
+// compatibility guarantees, once they've been widely adopted. See method docs
+// for details.
+//
+// Its zero value is valid to use.
+//
+// Any exported fields should be set before using methods on the type
+// and not changed thereafter.
+type LocalClient struct {
+	// Dial optionally specifies an alternate func that connects to the local
+	// machine's tailscaled or equivalent. If nil, a default is used.
+	Dial func(ctx context.Context, network, addr string) (net.Conn, error)
+
+	// Socket specifies an alternate path to the local Tailscale socket.
+	// If empty, a platform-specific default is used.
+	Socket string
+
+	// UseSocketOnly, if true, tries to only connect to tailscaled via the
+	// Unix socket and not via fallback mechanisms as done on macOS when
+	// connecting to the GUI client variants.
+	UseSocketOnly bool
+
+	// tsClient does HTTP requests to the local Tailscale daemon.
+	// It's lazily initialized on first use.
+	tsClient     *http.Client
+	tsClientOnce sync.Once
+}
+
+func (lc *LocalClient) socket() string {
+	if lc.Socket != "" {
+		return lc.Socket
+	}
+	return paths.DefaultTailscaledSocket()
+}
+
+func (lc *LocalClient) dialer() func(ctx context.Context, network, addr string) (net.Conn, error) {
+	if lc.Dial != nil {
+		return lc.Dial
+	}
+	return lc.defaultDialer
+}
+
+func (lc *LocalClient) defaultDialer(ctx context.Context, network, addr string) (net.Conn, error) {
+	if addr != "local-tailscaled.sock:80" {
+		return nil, fmt.Errorf("unexpected URL address %q", addr)
+	}
+	if !lc.UseSocketOnly {
+		// On macOS, when dialing from non-sandboxed program to sandboxed GUI running
+		// a TCP server on a random port, find the random port. For HTTP connections,
+		// we don't send the token. It gets added in an HTTP Basic-Auth header.
+		if port, _, err := safesocket.LocalTCPPortAndToken(); err == nil {
+			var d net.Dialer
+			return d.DialContext(ctx, "tcp", "localhost:"+strconv.Itoa(port))
+		}
+	}
+	s := safesocket.DefaultConnectionStrategy(lc.socket())
+	// The user provided a non-default tailscaled socket address.
+	// Connect only to exactly what they provided.
+	s.UseFallback(false)
+	return safesocket.Connect(s)
+}
+
+// DoLocalRequest makes an HTTP request to the local machine's Tailscale daemon.
+//
+// URLs are of the form http://local-tailscaled.sock/localapi/v0/whois?ip=1.2.3.4.
+//
+// The hostname must be "local-tailscaled.sock", even though it
+// doesn't actually do any DNS lookup. The actual means of connecting to and
+// authenticating to the local Tailscale daemon vary by platform.
+//
+// DoLocalRequest may mutate the request to add Authorization headers.
+func (lc *LocalClient) DoLocalRequest(req *http.Request) (*http.Response, error) {
+	lc.tsClientOnce.Do(func() {
+		lc.tsClient = &http.Client{
+			Transport: &http.Transport{
+				DialContext: lc.dialer(),
+			},
+		}
+	})
+	if _, token, err := safesocket.LocalTCPPortAndToken(); err == nil {
+		req.SetBasicAuth("", token)
+	}
+	return lc.tsClient.Do(req)
+}
+
+func (lc *LocalClient) doLocalRequestNiceError(req *http.Request) (*http.Response, error) {
+	res, err := lc.DoLocalRequest(req)
+	if err == nil {
+		if server := res.Header.Get("Tailscale-Version"); server != "" && server != ipn.IPCVersion() && onVersionMismatch != nil {
+			onVersionMismatch(ipn.IPCVersion(), server)
+		}
+		if res.StatusCode == 403 {
+			all, _ := ioutil.ReadAll(res.Body)
+			return nil, &AccessDeniedError{errors.New(errorMessageFromBody(all))}
+		}
+		return res, nil
+	}
+	if ue, ok := err.(*url.Error); ok {
+		if oe, ok := ue.Err.(*net.OpError); ok && oe.Op == "dial" {
+			path := req.URL.Path
+			pathPrefix, _, _ := strings.Cut(path, "?")
+			return nil, fmt.Errorf("Failed to connect to local Tailscale daemon for %s; %s Error: %w", pathPrefix, tailscaledConnectHint(), oe)
+		}
+	}
+	return nil, err
+}
+
+type errorJSON struct {
+	Error string
+}
+
+// AccessDeniedError is an error due to permissions.
+type AccessDeniedError struct {
+	err error
+}
+
+func (e *AccessDeniedError) Error() string { return fmt.Sprintf("Access denied: %v", e.err) }
+func (e *AccessDeniedError) Unwrap() error { return e.err }
+
+// IsAccessDeniedError reports whether err is or wraps an AccessDeniedError.
+func IsAccessDeniedError(err error) bool {
+	var ae *AccessDeniedError
+	return errors.As(err, &ae)
+}
+
+// bestError returns either err, or if body contains a valid JSON
+// object of type errorJSON, its non-empty error body.
+func bestError(err error, body []byte) error {
+	var j errorJSON
+	if err := json.Unmarshal(body, &j); err == nil && j.Error != "" {
+		return errors.New(j.Error)
+	}
+	return err
+}
+
+func errorMessageFromBody(body []byte) string {
+	var j errorJSON
+	if err := json.Unmarshal(body, &j); err == nil && j.Error != "" {
+		return j.Error
+	}
+	return strings.TrimSpace(string(body))
+}
+
+var onVersionMismatch func(clientVer, serverVer string)
+
+// SetVersionMismatchHandler sets f as the version mismatch handler
+// to be called when the client (the current process) has a version
+// number that doesn't match the server's declared version.
+func SetVersionMismatchHandler(f func(clientVer, serverVer string)) {
+	onVersionMismatch = f
+}
+
+func (lc *LocalClient) send(ctx context.Context, method, path string, wantStatus int, body io.Reader) ([]byte, error) {
+	req, err := http.NewRequestWithContext(ctx, method, "http://local-tailscaled.sock"+path, body)
+	if err != nil {
+		return nil, err
+	}
+	res, err := lc.doLocalRequestNiceError(req)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	slurp, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return nil, err
+	}
+	if res.StatusCode != wantStatus {
+		err = fmt.Errorf("%v: %s", res.Status, bytes.TrimSpace(slurp))
+		return nil, bestError(err, slurp)
+	}
+	return slurp, nil
+}
+
+func (lc *LocalClient) get200(ctx context.Context, path string) ([]byte, error) {
+	return lc.send(ctx, "GET", path, 200, nil)
+}
+
+// WhoIs returns the owner of the remoteAddr, which must be an IP or IP:port.
+//
+// Deprecated: use LocalClient.WhoIs.
+func WhoIs(ctx context.Context, remoteAddr string) (*apitype.WhoIsResponse, error) {
+	return defaultLocalClient.WhoIs(ctx, remoteAddr)
+}
+
+// WhoIs returns the owner of the remoteAddr, which must be an IP or IP:port.
+func (lc *LocalClient) WhoIs(ctx context.Context, remoteAddr string) (*apitype.WhoIsResponse, error) {
+	body, err := lc.get200(ctx, "/localapi/v0/whois?addr="+url.QueryEscape(remoteAddr))
+	if err != nil {
+		return nil, err
+	}
+	r := new(apitype.WhoIsResponse)
+	if err := json.Unmarshal(body, r); err != nil {
+		if max := 200; len(body) > max {
+			body = append(body[:max], "..."...)
+		}
+		return nil, fmt.Errorf("failed to parse JSON WhoIsResponse from %q", body)
+	}
+	return r, nil
+}
+
+// Goroutines returns a dump of the Tailscale daemon's current goroutines.
+func (lc *LocalClient) Goroutines(ctx context.Context) ([]byte, error) {
+	return lc.get200(ctx, "/localapi/v0/goroutines")
+}
+
+// DaemonMetrics returns the Tailscale daemon's metrics in
+// the Prometheus text exposition format.
+func (lc *LocalClient) DaemonMetrics(ctx context.Context) ([]byte, error) {
+	return lc.get200(ctx, "/localapi/v0/metrics")
+}
+
+// Profile returns a pprof profile of the Tailscale daemon.
+func (lc *LocalClient) Profile(ctx context.Context, pprofType string, sec int) ([]byte, error) {
+	var secArg string
+	if sec < 0 || sec > 300 {
+		return nil, errors.New("duration out of range")
+	}
+	if sec != 0 || pprofType == "profile" {
+		secArg = fmt.Sprint(sec)
+	}
+	return lc.get200(ctx, fmt.Sprintf("/localapi/v0/profile?name=%s&seconds=%v", url.QueryEscape(pprofType), secArg))
+}
+
+// BugReport logs and returns a log marker that can be shared by the user with support.
+func (lc *LocalClient) BugReport(ctx context.Context, note string) (string, error) {
+	body, err := lc.send(ctx, "POST", "/localapi/v0/bugreport?note="+url.QueryEscape(note), 200, nil)
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(string(body)), nil
+}
+
+// DebugAction invokes a debug action, such as "rebind" or "restun".
+// These are development tools and subject to change or removal over time.
+func (lc *LocalClient) DebugAction(ctx context.Context, action string) error {
+	body, err := lc.send(ctx, "POST", "/localapi/v0/debug?action="+url.QueryEscape(action), 200, nil)
+	if err != nil {
+		return fmt.Errorf("error %w: %s", err, body)
+	}
+	return nil
+}
+
+// Status returns the Tailscale daemon's status.
+func Status(ctx context.Context) (*ipnstate.Status, error) {
+	return defaultLocalClient.Status(ctx)
+}
+
+// Status returns the Tailscale daemon's status.
+func (lc *LocalClient) Status(ctx context.Context) (*ipnstate.Status, error) {
+	return lc.status(ctx, "")
+}
+
+// StatusWithoutPeers returns the Tailscale daemon's status, without the peer info.
+func StatusWithoutPeers(ctx context.Context) (*ipnstate.Status, error) {
+	return defaultLocalClient.StatusWithoutPeers(ctx)
+}
+
+// StatusWithoutPeers returns the Tailscale daemon's status, without the peer info.
+func (lc *LocalClient) StatusWithoutPeers(ctx context.Context) (*ipnstate.Status, error) {
+	return lc.status(ctx, "?peers=false")
+}
+
+func (lc *LocalClient) status(ctx context.Context, queryString string) (*ipnstate.Status, error) {
+	body, err := lc.get200(ctx, "/localapi/v0/status"+queryString)
+	if err != nil {
+		return nil, err
+	}
+	st := new(ipnstate.Status)
+	if err := json.Unmarshal(body, st); err != nil {
+		return nil, err
+	}
+	return st, nil
+}
+
+// IDToken is a request to get an OIDC ID token for an audience.
+// The token can be presented to any resource provider which offers OIDC
+// Federation.
+func (lc *LocalClient) IDToken(ctx context.Context, aud string) (*tailcfg.TokenResponse, error) {
+	body, err := lc.get200(ctx, "/localapi/v0/id-token?aud="+url.QueryEscape(aud))
+	if err != nil {
+		return nil, err
+	}
+	tr := new(tailcfg.TokenResponse)
+	if err := json.Unmarshal(body, tr); err != nil {
+		return nil, err
+	}
+	return tr, nil
+}
+
+func (lc *LocalClient) WaitingFiles(ctx context.Context) ([]apitype.WaitingFile, error) {
+	body, err := lc.get200(ctx, "/localapi/v0/files/")
+	if err != nil {
+		return nil, err
+	}
+	var wfs []apitype.WaitingFile
+	if err := json.Unmarshal(body, &wfs); err != nil {
+		return nil, err
+	}
+	return wfs, nil
+}
+
+func (lc *LocalClient) DeleteWaitingFile(ctx context.Context, baseName string) error {
+	_, err := lc.send(ctx, "DELETE", "/localapi/v0/files/"+url.PathEscape(baseName), http.StatusNoContent, nil)
+	return err
+}
+
+func (lc *LocalClient) GetWaitingFile(ctx context.Context, baseName string) (rc io.ReadCloser, size int64, err error) {
+	req, err := http.NewRequestWithContext(ctx, "GET", "http://local-tailscaled.sock/localapi/v0/files/"+url.PathEscape(baseName), nil)
+	if err != nil {
+		return nil, 0, err
+	}
+	res, err := lc.doLocalRequestNiceError(req)
+	if err != nil {
+		return nil, 0, err
+	}
+	if res.ContentLength == -1 {
+		res.Body.Close()
+		return nil, 0, fmt.Errorf("unexpected chunking")
+	}
+	if res.StatusCode != 200 {
+		body, _ := ioutil.ReadAll(res.Body)
+		res.Body.Close()
+		return nil, 0, fmt.Errorf("HTTP %s: %s", res.Status, body)
+	}
+	return res.Body, res.ContentLength, nil
+}
+
+func (lc *LocalClient) FileTargets(ctx context.Context) ([]apitype.FileTarget, error) {
+	body, err := lc.get200(ctx, "/localapi/v0/file-targets")
+	if err != nil {
+		return nil, err
+	}
+	var fts []apitype.FileTarget
+	if err := json.Unmarshal(body, &fts); err != nil {
+		return nil, fmt.Errorf("invalid JSON: %w", err)
+	}
+	return fts, nil
+}
+
+// PushFile sends Taildrop file r to target.
+//
+// A size of -1 means unknown.
+// The name parameter is the original filename, not escaped.
+func (lc *LocalClient) PushFile(ctx context.Context, target tailcfg.StableNodeID, size int64, name string, r io.Reader) error {
+	req, err := http.NewRequestWithContext(ctx, "PUT", "http://local-tailscaled.sock/localapi/v0/file-put/"+string(target)+"/"+url.PathEscape(name), r)
+	if err != nil {
+		return err
+	}
+	if size != -1 {
+		req.ContentLength = size
+	}
+	res, err := lc.doLocalRequestNiceError(req)
+	if err != nil {
+		return err
+	}
+	if res.StatusCode == 200 {
+		io.Copy(io.Discard, res.Body)
+		return nil
+	}
+	all, _ := io.ReadAll(res.Body)
+	return bestError(fmt.Errorf("%s: %s", res.Status, all), all)
+}
+
+// CheckIPForwarding asks the local Tailscale daemon whether it looks like the
+// machine is properly configured to forward IP packets as a subnet router
+// or exit node.
+func (lc *LocalClient) CheckIPForwarding(ctx context.Context) error {
+	body, err := lc.get200(ctx, "/localapi/v0/check-ip-forwarding")
+	if err != nil {
+		return err
+	}
+	var jres struct {
+		Warning string
+	}
+	if err := json.Unmarshal(body, &jres); err != nil {
+		return fmt.Errorf("invalid JSON from check-ip-forwarding: %w", err)
+	}
+	if jres.Warning != "" {
+		return errors.New(jres.Warning)
+	}
+	return nil
+}
+
+// CheckPrefs validates the provided preferences, without making any changes.
+//
+// The CLI uses this before a Start call to fail fast if the preferences won't
+// work. Currently (2022-04-18) this only checks for SSH server compatibility.
+// Note that EditPrefs does the same validation as this, so call CheckPrefs before
+// EditPrefs is not necessary.
+func (lc *LocalClient) CheckPrefs(ctx context.Context, p *ipn.Prefs) error {
+	pj, err := json.Marshal(p)
+	if err != nil {
+		return err
+	}
+	_, err = lc.send(ctx, "POST", "/localapi/v0/check-prefs", http.StatusOK, bytes.NewReader(pj))
+	return err
+}
+
+func (lc *LocalClient) GetPrefs(ctx context.Context) (*ipn.Prefs, error) {
+	body, err := lc.get200(ctx, "/localapi/v0/prefs")
+	if err != nil {
+		return nil, err
+	}
+	var p ipn.Prefs
+	if err := json.Unmarshal(body, &p); err != nil {
+		return nil, fmt.Errorf("invalid prefs JSON: %w", err)
+	}
+	return &p, nil
+}
+
+func (lc *LocalClient) EditPrefs(ctx context.Context, mp *ipn.MaskedPrefs) (*ipn.Prefs, error) {
+	mpj, err := json.Marshal(mp)
+	if err != nil {
+		return nil, err
+	}
+	body, err := lc.send(ctx, "PATCH", "/localapi/v0/prefs", http.StatusOK, bytes.NewReader(mpj))
+	if err != nil {
+		return nil, err
+	}
+	var p ipn.Prefs
+	if err := json.Unmarshal(body, &p); err != nil {
+		return nil, fmt.Errorf("invalid prefs JSON: %w", err)
+	}
+	return &p, nil
+}
+
+func (lc *LocalClient) Logout(ctx context.Context) error {
+	_, err := lc.send(ctx, "POST", "/localapi/v0/logout", http.StatusNoContent, nil)
+	return err
+}
+
+// SetDNS adds a DNS TXT record for the given domain name, containing
+// the provided TXT value. The intended use case is answering
+// LetsEncrypt/ACME dns-01 challenges.
+//
+// The control plane will only permit SetDNS requests with very
+// specific names and values. The name should be
+// "_acme-challenge." + your node's MagicDNS name. It's expected that
+// clients cache the certs from LetsEncrypt (or whichever CA is
+// providing them) and only request new ones as needed; the control plane
+// rate limits SetDNS requests.
+//
+// This is a low-level interface; it's expected that most Tailscale
+// users use a higher level interface to getting/using TLS
+// certificates.
+func (lc *LocalClient) SetDNS(ctx context.Context, name, value string) error {
+	v := url.Values{}
+	v.Set("name", name)
+	v.Set("value", value)
+	_, err := lc.send(ctx, "POST", "/localapi/v0/set-dns?"+v.Encode(), 200, nil)
+	return err
+}
+
+// DialTCP connects to the host's port via Tailscale.
+//
+// The host may be a base DNS name (resolved from the netmap inside
+// tailscaled), a FQDN, or an IP address.
+//
+// The ctx is only used for the duration of the call, not the lifetime of the net.Conn.
+func (lc *LocalClient) DialTCP(ctx context.Context, host string, port uint16) (net.Conn, error) {
+	connCh := make(chan net.Conn, 1)
+	trace := httptrace.ClientTrace{
+		GotConn: func(info httptrace.GotConnInfo) {
+			connCh <- info.Conn
+		},
+	}
+	ctx = httptrace.WithClientTrace(ctx, &trace)
+	req, err := http.NewRequestWithContext(ctx, "POST", "http://local-tailscaled.sock/localapi/v0/dial", nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header = http.Header{
+		"Upgrade":    []string{"ts-dial"},
+		"Connection": []string{"upgrade"},
+		"Dial-Host":  []string{host},
+		"Dial-Port":  []string{fmt.Sprint(port)},
+	}
+	res, err := lc.DoLocalRequest(req)
+	if err != nil {
+		return nil, err
+	}
+	if res.StatusCode != http.StatusSwitchingProtocols {
+		body, _ := io.ReadAll(res.Body)
+		res.Body.Close()
+		return nil, fmt.Errorf("unexpected HTTP response: %s, %s", res.Status, body)
+	}
+	// From here on, the underlying net.Conn is ours to use, but there
+	// is still a read buffer attached to it within resp.Body. So, we
+	// must direct I/O through resp.Body, but we can still use the
+	// underlying net.Conn for stuff like deadlines.
+	var switchedConn net.Conn
+	select {
+	case switchedConn = <-connCh:
+	default:
+	}
+	if switchedConn == nil {
+		res.Body.Close()
+		return nil, fmt.Errorf("httptrace didn't provide a connection")
+	}
+	rwc, ok := res.Body.(io.ReadWriteCloser)
+	if !ok {
+		res.Body.Close()
+		return nil, errors.New("http Transport did not provide a writable body")
+	}
+	return netutil.NewAltReadWriteCloserConn(rwc, switchedConn), nil
+}
+
+// CurrentDERPMap returns the current DERPMap that is being used by the local tailscaled.
+// It is intended to be used with netcheck to see availability of DERPs.
+func (lc *LocalClient) CurrentDERPMap(ctx context.Context) (*tailcfg.DERPMap, error) {
+	var derpMap tailcfg.DERPMap
+	res, err := lc.send(ctx, "GET", "/localapi/v0/derpmap", 200, nil)
+	if err != nil {
+		return nil, err
+	}
+	if err = json.Unmarshal(res, &derpMap); err != nil {
+		return nil, fmt.Errorf("invalid derp map json: %w", err)
+	}
+	return &derpMap, nil
+}
+
+// CertPair returns a cert and private key for the provided DNS domain.
+//
+// It returns a cached certificate from disk if it's still valid.
+//
+// Deprecated: use LocalClient.CertPair.
+func CertPair(ctx context.Context, domain string) (certPEM, keyPEM []byte, err error) {
+	return defaultLocalClient.CertPair(ctx, domain)
+}
+
+// CertPair returns a cert and private key for the provided DNS domain.
+//
+// It returns a cached certificate from disk if it's still valid.
+//
+// API maturity: this is considered a stable API.
+func (lc *LocalClient) CertPair(ctx context.Context, domain string) (certPEM, keyPEM []byte, err error) {
+	res, err := lc.send(ctx, "GET", "/localapi/v0/cert/"+domain+"?type=pair", 200, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+	// with ?type=pair, the response PEM is first the one private
+	// key PEM block, then the cert PEM blocks.
+	i := mem.Index(mem.B(res), mem.S("--\n--"))
+	if i == -1 {
+		return nil, nil, fmt.Errorf("unexpected output: no delimiter")
+	}
+	i += len("--\n")
+	keyPEM, certPEM = res[:i], res[i:]
+	if mem.Contains(mem.B(certPEM), mem.S(" PRIVATE KEY-----")) {
+		return nil, nil, fmt.Errorf("unexpected output: key in cert")
+	}
+	return certPEM, keyPEM, nil
+}
+
+// GetCertificate fetches a TLS certificate for the TLS ClientHello in hi.
+//
+// It returns a cached certificate from disk if it's still valid.
+//
+// It's the right signature to use as the value of
+// tls.Config.GetCertificate.
+//
+// Deprecated: use LocalClient.GetCertificate.
+func GetCertificate(hi *tls.ClientHelloInfo) (*tls.Certificate, error) {
+	return defaultLocalClient.GetCertificate(hi)
+}
+
+// GetCertificate fetches a TLS certificate for the TLS ClientHello in hi.
+//
+// It returns a cached certificate from disk if it's still valid.
+//
+// It's the right signature to use as the value of
+// tls.Config.GetCertificate.
+//
+// API maturity: this is considered a stable API.
+func (lc *LocalClient) GetCertificate(hi *tls.ClientHelloInfo) (*tls.Certificate, error) {
+	if hi == nil || hi.ServerName == "" {
+		return nil, errors.New("no SNI ServerName")
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+
+	name := hi.ServerName
+	if !strings.Contains(name, ".") {
+		if v, ok := lc.ExpandSNIName(ctx, name); ok {
+			name = v
+		}
+	}
+	certPEM, keyPEM, err := lc.CertPair(ctx, name)
+	if err != nil {
+		return nil, err
+	}
+	cert, err := tls.X509KeyPair(certPEM, keyPEM)
+	if err != nil {
+		return nil, err
+	}
+	return &cert, nil
+}
+
+// ExpandSNIName expands bare label name into the the most likely actual TLS cert name.
+//
+// Deprecated: use LocalClient.ExpandSNIName.
+func ExpandSNIName(ctx context.Context, name string) (fqdn string, ok bool) {
+	return defaultLocalClient.ExpandSNIName(ctx, name)
+}
+
+// ExpandSNIName expands bare label name into the the most likely actual TLS cert name.
+func (lc *LocalClient) ExpandSNIName(ctx context.Context, name string) (fqdn string, ok bool) {
+	st, err := lc.StatusWithoutPeers(ctx)
+	if err != nil {
+		return "", false
+	}
+	for _, d := range st.CertDomains {
+		if len(d) > len(name)+1 && strings.HasPrefix(d, name) && d[len(name)] == '.' {
+			return d, true
+		}
+	}
+	return "", false
+}
+
+// Ping sends a ping of the provided type to the provided IP and waits
+// for its response.
+func (lc *LocalClient) Ping(ctx context.Context, ip netip.Addr, pingtype tailcfg.PingType) (*ipnstate.PingResult, error) {
+	v := url.Values{}
+	v.Set("ip", ip.String())
+	v.Set("type", string(pingtype))
+	body, err := lc.send(ctx, "POST", "/localapi/v0/ping?"+v.Encode(), 200, nil)
+	if err != nil {
+		return nil, fmt.Errorf("error %w: %s", err, body)
+	}
+	pr := new(ipnstate.PingResult)
+	if err := json.Unmarshal(body, pr); err != nil {
+		return nil, err
+	}
+	return pr, nil
+}
+
+// tailscaledConnectHint gives a little thing about why tailscaled (or
+// platform equivalent) is not answering localapi connections.
+//
+// It ends in a punctuation. See caller.
+func tailscaledConnectHint() string {
+	if runtime.GOOS != "linux" {
+		// TODO(bradfitz): flesh this out
+		return "not running?"
+	}
+	out, err := exec.Command("systemctl", "show", "tailscaled.service", "--no-page", "--property", "LoadState,ActiveState,SubState").Output()
+	if err != nil {
+		return "not running?"
+	}
+	// Parse:
+	// LoadState=loaded
+	// ActiveState=inactive
+	// SubState=dead
+	st := map[string]string{}
+	for _, line := range strings.Split(string(out), "\n") {
+		if k, v, ok := strings.Cut(line, "="); ok {
+			st[k] = strings.TrimSpace(v)
+		}
+	}
+	if st["LoadState"] == "loaded" &&
+		(st["SubState"] != "running" || st["ActiveState"] != "active") {
+		return "systemd tailscaled.service not running."
+	}
+	return "not running?"
+}

client/tailscale/required_version.go

@@ -0,0 +1,12 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.18
+// +build !go1.18
+
+package tailscale
+
+func init() {
+	you_need_Go_1_18_to_compile_Tailscale()
+}

client/tailscale/routes.go

@@ -0,0 +1,97 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+// +build go1.18
+
+package tailscale
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/netip"
+)
+
+// Routes contains the lists of subnet routes that are currently advertised by a device,
+// as well as the subnets that are enabled to be routed by the device.
+type Routes struct {
+	AdvertisedRoutes []netip.Prefix `json:"advertisedRoutes"`
+	EnabledRoutes    []netip.Prefix `json:"enabledRoutes"`
+}
+
+// Routes retrieves the list of subnet routes that have been enabled for a device.
+// The routes that are returned are not necessarily advertised by the device,
+// they have only been preapproved.
+func (c *Client) Routes(ctx context.Context, deviceID string) (routes *Routes, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.Routes: %w", err)
+		}
+	}()
+
+	path := fmt.Sprintf("%s/api/v2/device/%s/routes", c.baseURL(), deviceID)
+	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	var sr Routes
+	err = json.Unmarshal(b, &sr)
+	return &sr, err
+}
+
+type postRoutesParams struct {
+	Routes []netip.Prefix `json:"routes"`
+}
+
+// SetRoutes updates the list of subnets that are enabled for a device.
+// Subnets must be parsable by net/netip.ParsePrefix.
+// Subnets do not have to be currently advertised by a device, they may be pre-enabled.
+// Returns the updated list of enabled and advertised subnet routes in a *Routes object.
+func (c *Client) SetRoutes(ctx context.Context, deviceID string, subnets []netip.Prefix) (routes *Routes, err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.SetRoutes: %w", err)
+		}
+	}()
+	params := &postRoutesParams{Routes: subnets}
+	data, err := json.Marshal(params)
+	if err != nil {
+		return nil, err
+	}
+	path := fmt.Sprintf("%s/api/v2/device/%s/routes", c.baseURL(), deviceID)
+	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(data))
+	if err != nil {
+		return nil, err
+	}
+
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, err
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+
+	var srr *Routes
+	if err := json.Unmarshal(b, &srr); err != nil {
+		return nil, err
+	}
+	return srr, err
+}

client/tailscale/tailnet.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+// +build go1.18
+
+package tailscale
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/url"
+)
+
+// TailnetDeleteRequest handles sending a DELETE request for a tailnet to control.
+func (c *Client) TailnetDeleteRequest(ctx context.Context, tailnetID string) (err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("tailscale.DeleteTailnet: %w", err)
+		}
+	}()
+
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s", c.baseURL(), url.PathEscape(string(tailnetID)))
+	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, path, nil)
+	if err != nil {
+		return err
+	}
+
+	c.setAuth(req)
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return handleErrorResponse(b, resp)
+	}
+
+	return nil
+}

client/tailscale/tailscale.go

@@ -1,529 +1,160 @@
-// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package tailscale contains Tailscale client code.
+//go:build go1.18
+// +build go1.18
+
+// Package tailscale contains Go clients for the Tailscale Local API and
+// Tailscale control plane API.
+//
+// Warning: this package is in development and makes no API compatibility
+// promises as of 2022-04-29. It is subject to change at any time.
 package tailscale
 
 import (
-	"bytes"
-	"context"
-	"crypto/tls"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
-	"net"
 	"net/http"
-	"net/url"
-	"os/exec"
-	"runtime"
-	"strconv"
-	"strings"
-	"sync"
-	"time"
-
-	"go4.org/mem"
-	"tailscale.com/client/tailscale/apitype"
-	"tailscale.com/ipn"
-	"tailscale.com/ipn/ipnstate"
-	"tailscale.com/paths"
-	"tailscale.com/safesocket"
-	"tailscale.com/tailcfg"
-	"tailscale.com/version"
 )
 
-var (
-	// TailscaledSocket is the tailscaled Unix socket. It's used by the TailscaledDialer.
-	TailscaledSocket = paths.DefaultTailscaledSocket()
-
-	// TailscaledSocketSetExplicitly reports whether the user explicitly set TailscaledSocket.
-	TailscaledSocketSetExplicitly bool
-
-	// TailscaledDialer is the DialContext func that connects to the local machine's
-	// tailscaled or equivalent.
-	TailscaledDialer = defaultDialer
-)
-
-func defaultDialer(ctx context.Context, network, addr string) (net.Conn, error) {
-	if addr != "local-tailscaled.sock:80" {
-		return nil, fmt.Errorf("unexpected URL address %q", addr)
-	}
-	// TODO: make this part of a safesocket.ConnectionStrategy
-	if !TailscaledSocketSetExplicitly {
-		// On macOS, when dialing from non-sandboxed program to sandboxed GUI running
-		// a TCP server on a random port, find the random port. For HTTP connections,
-		// we don't send the token. It gets added in an HTTP Basic-Auth header.
-		if port, _, err := safesocket.LocalTCPPortAndToken(); err == nil {
-			var d net.Dialer
-			return d.DialContext(ctx, "tcp", "localhost:"+strconv.Itoa(port))
-		}
-	}
-	s := safesocket.DefaultConnectionStrategy(TailscaledSocket)
-	// The user provided a non-default tailscaled socket address.
-	// Connect only to exactly what they provided.
-	s.UseFallback(false)
-	return safesocket.Connect(s)
-}
-
-var (
-	// tsClient does HTTP requests to the local Tailscale daemon.
-	// We lazily initialize the client in case the caller wants to
-	// override TailscaledDialer.
-	tsClient     *http.Client
-	tsClientOnce sync.Once
-)
-
-// DoLocalRequest makes an HTTP request to the local machine's Tailscale daemon.
+// I_Acknowledge_This_API_Is_Unstable must be set true to use this package
+// for now. It was added 2022-04-29 when it was moved to this git repo
+// and will be removed when the public API has settled.
 //
-// URLs are of the form http://local-tailscaled.sock/localapi/v0/whois?ip=1.2.3.4.
+// TODO(bradfitz): remove this after the we're happy with the public API.
+var I_Acknowledge_This_API_Is_Unstable = false
+
+// TODO: use url.PathEscape() for deviceID and tailnets when constructing requests.
+
+const defaultAPIBase = "https://api.tailscale.com"
+
+// maxSize is the maximum read size (10MB) of responses from the server.
+const maxReadSize = 10 << 20
+
+// Client makes API calls to the Tailscale control plane API server.
 //
-// The hostname must be "local-tailscaled.sock", even though it
-// doesn't actually do any DNS lookup. The actual means of connecting to and
-// authenticating to the local Tailscale daemon vary by platform.
+// Use NewClient to instantiate one. Exported fields should be set before
+// the client is used and not changed thereafter.
+type Client struct {
+	// tailnet is the globally unique identifier for a Tailscale network, such
+	// as "example.com" or "user@gmail.com".
+	tailnet string
+	// auth is the authentication method to use for this client.
+	// nil means none, which generally won't work, but won't crash.
+	auth AuthMethod
+
+	// BaseURL optionally specifies an alternate API server to use.
+	// If empty, "https://api.tailscale.com" is used.
+	BaseURL string
+
+	// HTTPClient optionally specifies an alternate HTTP client to use.
+	// If nil, http.DefaultClient is used.
+	HTTPClient *http.Client
+}
+
+func (c *Client) httpClient() *http.Client {
+	if c.HTTPClient != nil {
+		return c.HTTPClient
+	}
+	return http.DefaultClient
+}
+
+func (c *Client) baseURL() string {
+	if c.BaseURL != "" {
+		return c.BaseURL
+	}
+	return defaultAPIBase
+}
+
+// AuthMethod is the interface for API authentication methods.
 //
-// DoLocalRequest may mutate the request to add Authorization headers.
-func DoLocalRequest(req *http.Request) (*http.Response, error) {
-	tsClientOnce.Do(func() {
-		tsClient = &http.Client{
-			Transport: &http.Transport{
-				DialContext: TailscaledDialer,
-			},
-		}
-	})
-	if _, token, err := safesocket.LocalTCPPortAndToken(); err == nil {
-		req.SetBasicAuth("", token)
-	}
-	return tsClient.Do(req)
+// Most users will use AuthKey.
+type AuthMethod interface {
+	modifyRequest(req *http.Request)
 }
 
-func doLocalRequestNiceError(req *http.Request) (*http.Response, error) {
-	res, err := DoLocalRequest(req)
-	if err == nil {
-		if server := res.Header.Get("Tailscale-Version"); server != "" && server != version.Long && onVersionMismatch != nil {
-			onVersionMismatch(version.Long, server)
-		}
-		if res.StatusCode == 403 {
-			all, _ := ioutil.ReadAll(res.Body)
-			return nil, &AccessDeniedError{errors.New(errorMessageFromBody(all))}
-		}
-		return res, nil
-	}
-	if ue, ok := err.(*url.Error); ok {
-		if oe, ok := ue.Err.(*net.OpError); ok && oe.Op == "dial" {
-			path := req.URL.Path
-			pathPrefix := path
-			if i := strings.Index(path, "?"); i != -1 {
-				pathPrefix = path[:i]
-			}
-			return nil, fmt.Errorf("Failed to connect to local Tailscale daemon for %s; %s Error: %w", pathPrefix, tailscaledConnectHint(), oe)
-		}
-	}
-	return nil, err
+// APIKey is an AuthMethod for NewClient that authenticates requests
+// using an authkey.
+type APIKey string
+
+func (ak APIKey) modifyRequest(req *http.Request) {
+	req.SetBasicAuth(string(ak), "")
 }
 
-type errorJSON struct {
-	Error string
+func (c *Client) setAuth(r *http.Request) {
+	if c.auth != nil {
+		c.auth.modifyRequest(r)
+	}
 }
 
-// AccessDeniedError is an error due to permissions.
-type AccessDeniedError struct {
-	err error
-}
-
-func (e *AccessDeniedError) Error() string { return fmt.Sprintf("Access denied: %v", e.err) }
-func (e *AccessDeniedError) Unwrap() error { return e.err }
-
-// IsAccessDeniedError reports whether err is or wraps an AccessDeniedError.
-func IsAccessDeniedError(err error) bool {
-	var ae *AccessDeniedError
-	return errors.As(err, &ae)
-}
-
-// bestError returns either err, or if body contains a valid JSON
-// object of type errorJSON, its non-empty error body.
-func bestError(err error, body []byte) error {
-	var j errorJSON
-	if err := json.Unmarshal(body, &j); err == nil && j.Error != "" {
-		return errors.New(j.Error)
-	}
-	return err
-}
-
-func errorMessageFromBody(body []byte) string {
-	var j errorJSON
-	if err := json.Unmarshal(body, &j); err == nil && j.Error != "" {
-		return j.Error
-	}
-	return strings.TrimSpace(string(body))
-}
-
-var onVersionMismatch func(clientVer, serverVer string)
-
-// SetVersionMismatchHandler sets f as the version mismatch handler
-// to be called when the client (the current process) has a version
-// number that doesn't match the server's declared version.
-func SetVersionMismatchHandler(f func(clientVer, serverVer string)) {
-	onVersionMismatch = f
-}
-
-func send(ctx context.Context, method, path string, wantStatus int, body io.Reader) ([]byte, error) {
-	req, err := http.NewRequestWithContext(ctx, method, "http://local-tailscaled.sock"+path, body)
-	if err != nil {
-		return nil, err
-	}
-	res, err := doLocalRequestNiceError(req)
-	if err != nil {
-		return nil, err
-	}
-	defer res.Body.Close()
-	slurp, err := ioutil.ReadAll(res.Body)
-	if err != nil {
-		return nil, err
-	}
-	if res.StatusCode != wantStatus {
-		return nil, bestError(err, slurp)
-	}
-	return slurp, nil
-}
-
-func get200(ctx context.Context, path string) ([]byte, error) {
-	return send(ctx, "GET", path, 200, nil)
-}
-
-// WhoIs returns the owner of the remoteAddr, which must be an IP or IP:port.
-func WhoIs(ctx context.Context, remoteAddr string) (*apitype.WhoIsResponse, error) {
-	body, err := get200(ctx, "/localapi/v0/whois?addr="+url.QueryEscape(remoteAddr))
-	if err != nil {
-		return nil, err
-	}
-	r := new(apitype.WhoIsResponse)
-	if err := json.Unmarshal(body, r); err != nil {
-		if max := 200; len(body) > max {
-			body = append(body[:max], "..."...)
-		}
-		return nil, fmt.Errorf("failed to parse JSON WhoIsResponse from %q", body)
-	}
-	return r, nil
-}
-
-// Goroutines returns a dump of the Tailscale daemon's current goroutines.
-func Goroutines(ctx context.Context) ([]byte, error) {
-	return get200(ctx, "/localapi/v0/goroutines")
-}
-
-// DaemonMetrics returns the Tailscale daemon's metrics in
-// the Prometheus text exposition format.
-func DaemonMetrics(ctx context.Context) ([]byte, error) {
-	return get200(ctx, "/localapi/v0/metrics")
-}
-
-// Profile returns a pprof profile of the Tailscale daemon.
-func Profile(ctx context.Context, pprofType string, sec int) ([]byte, error) {
-	var secArg string
-	if sec < 0 || sec > 300 {
-		return nil, errors.New("duration out of range")
-	}
-	if sec != 0 || pprofType == "profile" {
-		secArg = fmt.Sprint(sec)
-	}
-	return get200(ctx, fmt.Sprintf("/localapi/v0/profile?name=%s&seconds=%v", url.QueryEscape(pprofType), secArg))
-}
-
-// BugReport logs and returns a log marker that can be shared by the user with support.
-func BugReport(ctx context.Context, note string) (string, error) {
-	body, err := send(ctx, "POST", "/localapi/v0/bugreport?note="+url.QueryEscape(note), 200, nil)
-	if err != nil {
-		return "", err
-	}
-	return strings.TrimSpace(string(body)), nil
-}
-
-// DebugAction invokes a debug action, such as "rebind" or "restun".
-// These are development tools and subject to change or removal over time.
-func DebugAction(ctx context.Context, action string) error {
-	body, err := send(ctx, "POST", "/localapi/v0/debug?action="+url.QueryEscape(action), 200, nil)
-	if err != nil {
-		return fmt.Errorf("error %w: %s", err, body)
-	}
-	return nil
-}
-
-// Status returns the Tailscale daemon's status.
-func Status(ctx context.Context) (*ipnstate.Status, error) {
-	return status(ctx, "")
-}
-
-// StatusWithoutPeers returns the Tailscale daemon's status, without the peer info.
-func StatusWithoutPeers(ctx context.Context) (*ipnstate.Status, error) {
-	return status(ctx, "?peers=false")
-}
-
-func status(ctx context.Context, queryString string) (*ipnstate.Status, error) {
-	body, err := get200(ctx, "/localapi/v0/status"+queryString)
-	if err != nil {
-		return nil, err
-	}
-	st := new(ipnstate.Status)
-	if err := json.Unmarshal(body, st); err != nil {
-		return nil, err
-	}
-	return st, nil
-}
-
-func WaitingFiles(ctx context.Context) ([]apitype.WaitingFile, error) {
-	body, err := get200(ctx, "/localapi/v0/files/")
-	if err != nil {
-		return nil, err
-	}
-	var wfs []apitype.WaitingFile
-	if err := json.Unmarshal(body, &wfs); err != nil {
-		return nil, err
-	}
-	return wfs, nil
-}
-
-func DeleteWaitingFile(ctx context.Context, baseName string) error {
-	_, err := send(ctx, "DELETE", "/localapi/v0/files/"+url.PathEscape(baseName), http.StatusNoContent, nil)
-	return err
-}
-
-func GetWaitingFile(ctx context.Context, baseName string) (rc io.ReadCloser, size int64, err error) {
-	req, err := http.NewRequestWithContext(ctx, "GET", "http://local-tailscaled.sock/localapi/v0/files/"+url.PathEscape(baseName), nil)
-	if err != nil {
-		return nil, 0, err
-	}
-	res, err := doLocalRequestNiceError(req)
-	if err != nil {
-		return nil, 0, err
-	}
-	if res.ContentLength == -1 {
-		res.Body.Close()
-		return nil, 0, fmt.Errorf("unexpected chunking")
-	}
-	if res.StatusCode != 200 {
-		body, _ := ioutil.ReadAll(res.Body)
-		res.Body.Close()
-		return nil, 0, fmt.Errorf("HTTP %s: %s", res.Status, body)
-	}
-	return res.Body, res.ContentLength, nil
-}
-
-func FileTargets(ctx context.Context) ([]apitype.FileTarget, error) {
-	body, err := get200(ctx, "/localapi/v0/file-targets")
-	if err != nil {
-		return nil, err
-	}
-	var fts []apitype.FileTarget
-	if err := json.Unmarshal(body, &fts); err != nil {
-		return nil, fmt.Errorf("invalid JSON: %w", err)
-	}
-	return fts, nil
-}
-
-// PushFile sends Taildrop file r to target.
+// NewClient is a convenience method for instantiating a new Client.
 //
-// A size of -1 means unknown.
-// The name parameter is the original filename, not escaped.
-func PushFile(ctx context.Context, target tailcfg.StableNodeID, size int64, name string, r io.Reader) error {
-	req, err := http.NewRequestWithContext(ctx, "PUT", "http://local-tailscaled.sock/localapi/v0/file-put/"+string(target)+"/"+url.PathEscape(name), r)
+// tailnet is the globally unique identifier for a Tailscale network, such
+// as "example.com" or "user@gmail.com".
+// If httpClient is nil, then http.DefaultClient is used.
+// "api.tailscale.com" is set as the BaseURL for the returned client
+// and can be changed manually by the user.
+func NewClient(tailnet string, auth AuthMethod) *Client {
+	return &Client{
+		tailnet: tailnet,
+		auth:    auth,
+	}
+}
+
+func (c *Client) Tailnet() string { return c.tailnet }
+
+// Do sends a raw HTTP request, after adding any authentication headers.
+func (c *Client) Do(req *http.Request) (*http.Response, error) {
+	if !I_Acknowledge_This_API_Is_Unstable {
+		return nil, errors.New("use of Client without setting I_Acknowledge_This_API_Is_Unstable")
+	}
+	c.setAuth(req)
+	return c.httpClient().Do(req)
+}
+
+// sendRequest add the authenication key to the request and sends it. It
+// receives the response and reads up to 10MB of it.
+func (c *Client) sendRequest(req *http.Request) ([]byte, *http.Response, error) {
+	if !I_Acknowledge_This_API_Is_Unstable {
+		return nil, nil, errors.New("use of Client without setting I_Acknowledge_This_API_Is_Unstable")
+	}
+	c.setAuth(req)
+	resp, err := c.httpClient().Do(req)
 	if err != nil {
+		return nil, resp, err
+	}
+	defer resp.Body.Close()
+
+	// Read response. Limit the response to 10MB.
+	body := io.LimitReader(resp.Body, maxReadSize+1)
+	b, err := ioutil.ReadAll(body)
+	if len(b) > maxReadSize {
+		err = errors.New("API response too large")
+	}
+	return b, resp, err
+}
+
+// ErrResponse is the HTTP error returned by the Tailscale server.
+type ErrResponse struct {
+	Status  int
+	Message string
+}
+
+func (e ErrResponse) Error() string {
+	return fmt.Sprintf("Status: %d, Message: %q", e.Status, e.Message)
+}
+
+// handleErrorResponse decodes the error message from the server and returns
+// an ErrResponse from it.
+func handleErrorResponse(b []byte, resp *http.Response) error {
+	var errResp ErrResponse
+	if err := json.Unmarshal(b, &errResp); err != nil {
 		return err
 	}
-	if size != -1 {
-		req.ContentLength = size
-	}
-	res, err := doLocalRequestNiceError(req)
-	if err != nil {
-		return err
-	}
-	if res.StatusCode == 200 {
-		io.Copy(io.Discard, res.Body)
-		return nil
-	}
-	all, _ := io.ReadAll(res.Body)
-	return bestError(fmt.Errorf("%s: %s", res.Status, all), all)
-}
-
-func CheckIPForwarding(ctx context.Context) error {
-	body, err := get200(ctx, "/localapi/v0/check-ip-forwarding")
-	if err != nil {
-		return err
-	}
-	var jres struct {
-		Warning string
-	}
-	if err := json.Unmarshal(body, &jres); err != nil {
-		return fmt.Errorf("invalid JSON from check-ip-forwarding: %w", err)
-	}
-	if jres.Warning != "" {
-		return errors.New(jres.Warning)
-	}
-	return nil
-}
-
-func GetPrefs(ctx context.Context) (*ipn.Prefs, error) {
-	body, err := get200(ctx, "/localapi/v0/prefs")
-	if err != nil {
-		return nil, err
-	}
-	var p ipn.Prefs
-	if err := json.Unmarshal(body, &p); err != nil {
-		return nil, fmt.Errorf("invalid prefs JSON: %w", err)
-	}
-	return &p, nil
-}
-
-func EditPrefs(ctx context.Context, mp *ipn.MaskedPrefs) (*ipn.Prefs, error) {
-	mpj, err := json.Marshal(mp)
-	if err != nil {
-		return nil, err
-	}
-	body, err := send(ctx, "PATCH", "/localapi/v0/prefs", http.StatusOK, bytes.NewReader(mpj))
-	if err != nil {
-		return nil, err
-	}
-	var p ipn.Prefs
-	if err := json.Unmarshal(body, &p); err != nil {
-		return nil, fmt.Errorf("invalid prefs JSON: %w", err)
-	}
-	return &p, nil
-}
-
-func Logout(ctx context.Context) error {
-	_, err := send(ctx, "POST", "/localapi/v0/logout", http.StatusNoContent, nil)
-	return err
-}
-
-// SetDNS adds a DNS TXT record for the given domain name, containing
-// the provided TXT value. The intended use case is answering
-// LetsEncrypt/ACME dns-01 challenges.
-//
-// The control plane will only permit SetDNS requests with very
-// specific names and values. The name should be
-// "_acme-challenge." + your node's MagicDNS name. It's expected that
-// clients cache the certs from LetsEncrypt (or whichever CA is
-// providing them) and only request new ones as needed; the control plane
-// rate limits SetDNS requests.
-//
-// This is a low-level interface; it's expected that most Tailscale
-// users use a higher level interface to getting/using TLS
-// certificates.
-func SetDNS(ctx context.Context, name, value string) error {
-	v := url.Values{}
-	v.Set("name", name)
-	v.Set("value", value)
-	_, err := send(ctx, "POST", "/localapi/v0/set-dns?"+v.Encode(), 200, nil)
-	return err
-}
-
-// CurrentDERPMap returns the current DERPMap that is being used by the local tailscaled.
-// It is intended to be used with netcheck to see availability of DERPs.
-func CurrentDERPMap(ctx context.Context) (*tailcfg.DERPMap, error) {
-	var derpMap tailcfg.DERPMap
-	res, err := send(ctx, "GET", "/localapi/v0/derpmap", 200, nil)
-	if err != nil {
-		return nil, err
-	}
-	if err = json.Unmarshal(res, &derpMap); err != nil {
-		return nil, fmt.Errorf("invalid derp map json: %w", err)
-	}
-	return &derpMap, nil
-}
-
-// CertPair returns a cert and private key for the provided DNS domain.
-//
-// It returns a cached certificate from disk if it's still valid.
-func CertPair(ctx context.Context, domain string) (certPEM, keyPEM []byte, err error) {
-	res, err := send(ctx, "GET", "/localapi/v0/cert/"+domain+"?type=pair", 200, nil)
-	if err != nil {
-		return nil, nil, err
-	}
-	// with ?type=pair, the response PEM is first the one private
-	// key PEM block, then the cert PEM blocks.
-	i := mem.Index(mem.B(res), mem.S("--\n--"))
-	if i == -1 {
-		return nil, nil, fmt.Errorf("unexpected output: no delimiter")
-	}
-	i += len("--\n")
-	keyPEM, certPEM = res[:i], res[i:]
-	if mem.Contains(mem.B(certPEM), mem.S(" PRIVATE KEY-----")) {
-		return nil, nil, fmt.Errorf("unexpected output: key in cert")
-	}
-	return certPEM, keyPEM, nil
-}
-
-// GetCertificate fetches a TLS certificate for the TLS ClientHello in hi.
-//
-// It returns a cached certificate from disk if it's still valid.
-//
-// It's the right signature to use as the value of
-// tls.Config.GetCertificate.
-func GetCertificate(hi *tls.ClientHelloInfo) (*tls.Certificate, error) {
-	if hi == nil || hi.ServerName == "" {
-		return nil, errors.New("no SNI ServerName")
-	}
-	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
-	defer cancel()
-
-	name := hi.ServerName
-	if !strings.Contains(name, ".") {
-		if v, ok := ExpandSNIName(ctx, name); ok {
-			name = v
-		}
-	}
-	certPEM, keyPEM, err := CertPair(ctx, name)
-	if err != nil {
-		return nil, err
-	}
-	cert, err := tls.X509KeyPair(certPEM, keyPEM)
-	if err != nil {
-		return nil, err
-	}
-	return &cert, nil
-}
-
-// ExpandSNIName expands bare label name into the the most likely actual TLS cert name.
-func ExpandSNIName(ctx context.Context, name string) (fqdn string, ok bool) {
-	st, err := StatusWithoutPeers(ctx)
-	if err != nil {
-		return "", false
-	}
-	for _, d := range st.CertDomains {
-		if len(d) > len(name)+1 && strings.HasPrefix(d, name) && d[len(name)] == '.' {
-			return d, true
-		}
-	}
-	return "", false
-}
-
-// tailscaledConnectHint gives a little thing about why tailscaled (or
-// platform equivalent) is not answering localapi connections.
-//
-// It ends in a punctuation. See caller.
-func tailscaledConnectHint() string {
-	if runtime.GOOS != "linux" {
-		// TODO(bradfitz): flesh this out
-		return "not running?"
-	}
-	out, err := exec.Command("systemctl", "show", "tailscaled.service", "--no-page", "--property", "LoadState,ActiveState,SubState").Output()
-	if err != nil {
-		return "not running?"
-	}
-	// Parse:
-	// LoadState=loaded
-	// ActiveState=inactive
-	// SubState=dead
-	st := map[string]string{}
-	for _, line := range strings.Split(string(out), "\n") {
-		if i := strings.Index(line, "="); i != -1 {
-			st[line[:i]] = strings.TrimSpace(line[i+1:])
-		}
-	}
-	if st["LoadState"] == "loaded" &&
-		(st["SubState"] != "running" || st["ActiveState"] != "active") {
-		return "systemd tailscaled.service not running."
-	}
-	return "not running?"
+	errResp.Status = resp.StatusCode
+	return errResp
 }

cmd/cloner/cloner.go

@@ -22,13 +22,11 @@ import (
 	"os"
 	"strings"
 
-	"golang.org/x/tools/go/packages"
 	"tailscale.com/util/codegen"
 )
 
 var (
 	flagTypes     = flag.String("type", "", "comma-separated list of types; required")
-	flagOutput    = flag.String("output", "", "output file; required")
 	flagBuildTags = flag.String("tags", "", "compiler build tags to apply")
 	flagCloneFunc = flag.Bool("clonefunc", false, "add a top-level Clone func")
 )
@@ -43,40 +41,28 @@ func main() {
 	}
 	typeNames := strings.Split(*flagTypes, ",")
 
-	cfg := &packages.Config{
-		Mode:  packages.NeedTypes | packages.NeedTypesInfo | packages.NeedSyntax | packages.NeedName,
-		Tests: false,
-	}
-	if *flagBuildTags != "" {
-		cfg.BuildFlags = []string{"-tags=" + *flagBuildTags}
-	}
-	pkgs, err := packages.Load(cfg, ".")
+	pkg, namedTypes, err := codegen.LoadTypes(*flagBuildTags, ".")
 	if err != nil {
 		log.Fatal(err)
 	}
-	if len(pkgs) != 1 {
-		log.Fatalf("wrong number of packages: %d", len(pkgs))
-	}
-	pkg := pkgs[0]
+	it := codegen.NewImportTracker(pkg.Types)
 	buf := new(bytes.Buffer)
-	imports := make(map[string]struct{})
-	namedTypes := codegen.NamedTypes(pkg)
 	for _, typeName := range typeNames {
 		typ, ok := namedTypes[typeName]
 		if !ok {
 			log.Fatalf("could not find type %s", typeName)
 		}
-		gen(buf, imports, typ, pkg.Types)
+		gen(buf, it, typ)
 	}
 
-	w := func(format string, args ...interface{}) {
+	w := func(format string, args ...any) {
 		fmt.Fprintf(buf, format+"\n", args...)
 	}
 	if *flagCloneFunc {
 		w("// Clone duplicates src into dst and reports whether it succeeded.")
 		w("// To succeed, <src, dst> must be of types <*T, *T> or <*T, **T>,")
 		w("// where T is one of %s.", *flagTypes)
-		w("func Clone(dst, src interface{}) bool {")
+		w("func Clone(dst, src any) bool {")
 		w("	switch src := src.(type) {")
 		for _, typeName := range typeNames {
 			w("	case *%s:", typeName)
@@ -93,62 +79,13 @@ func main() {
 		w("	return false")
 		w("}")
 	}
-
-	contents := new(bytes.Buffer)
-	var flagArgs []string
-	if *flagTypes != "" {
-		flagArgs = append(flagArgs, "-type="+*flagTypes)
-	}
-	if *flagOutput != "" {
-		flagArgs = append(flagArgs, "-output="+*flagOutput)
-	}
-	if *flagBuildTags != "" {
-		flagArgs = append(flagArgs, "-tags="+*flagBuildTags)
-	}
-	if *flagCloneFunc {
-		flagArgs = append(flagArgs, "-clonefunc")
-	}
-	fmt.Fprintf(contents, header, strings.Join(flagArgs, " "), pkg.Name)
-	fmt.Fprintf(contents, "import (\n")
-	for s := range imports {
-		fmt.Fprintf(contents, "\t%q\n", s)
-	}
-	fmt.Fprintf(contents, ")\n\n")
-	contents.Write(buf.Bytes())
-
-	output := *flagOutput
-	if output == "" {
-		flag.Usage()
-		os.Exit(2)
-	}
-	if err := codegen.WriteFormatted(contents.Bytes(), output); err != nil {
+	cloneOutput := pkg.Name + "_clone.go"
+	if err := codegen.WritePackageFile("tailscale.com/cmd/cloner", pkg, cloneOutput, it, buf); err != nil {
 		log.Fatal(err)
 	}
 }
 
-const header = `// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Code generated by tailscale.com/cmd/cloner; DO NOT EDIT.
-//` + `go:generate` + ` go run tailscale.com/cmd/cloner %s
-
-package %s
-
-`
-
-func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisPkg *types.Package) {
-	pkgQual := func(pkg *types.Package) string {
-		if thisPkg == pkg {
-			return ""
-		}
-		imports[pkg.Path()] = struct{}{}
-		return pkg.Name()
-	}
-	importedName := func(t types.Type) string {
-		return types.TypeString(t, pkgQual)
-	}
-
+func gen(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named) {
 	t, ok := typ.Underlying().(*types.Struct)
 	if !ok {
 		return
@@ -158,7 +95,7 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
 	fmt.Fprintf(buf, "// Clone makes a deep copy of %s.\n", name)
 	fmt.Fprintf(buf, "// The result aliases no memory with the original.\n")
 	fmt.Fprintf(buf, "func (src *%s) Clone() *%s {\n", name, name)
-	writef := func(format string, args ...interface{}) {
+	writef := func(format string, args ...any) {
 		fmt.Fprintf(buf, "\t"+format+"\n", args...)
 	}
 	writef("if src == nil {")
@@ -169,21 +106,32 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
 	for i := 0; i < t.NumFields(); i++ {
 		fname := t.Field(i).Name()
 		ft := t.Field(i).Type()
-		if !codegen.ContainsPointers(ft) {
+		if !codegen.ContainsPointers(ft) || codegen.HasNoClone(t.Tag(i)) {
 			continue
 		}
-		if named, _ := ft.(*types.Named); named != nil && !hasBasicUnderlying(ft) {
-			writef("dst.%s = *src.%s.Clone()", fname, fname)
-			continue
+		if named, _ := ft.(*types.Named); named != nil {
+			if codegen.IsViewType(ft) {
+				writef("dst.%s = src.%s", fname, fname)
+				continue
+			}
+			if !hasBasicUnderlying(ft) {
+				writef("dst.%s = *src.%s.Clone()", fname, fname)
+				continue
+			}
 		}
 		switch ft := ft.Underlying().(type) {
 		case *types.Slice:
 			if codegen.ContainsPointers(ft.Elem()) {
-				n := importedName(ft.Elem())
+				n := it.QualifiedName(ft.Elem())
 				writef("dst.%s = make([]%s, len(src.%s))", fname, n, fname)
 				writef("for i := range dst.%s {", fname)
-				if _, isPtr := ft.Elem().(*types.Pointer); isPtr {
-					writef("\tdst.%s[i] = src.%s[i].Clone()", fname, fname)
+				if ptr, isPtr := ft.Elem().(*types.Pointer); isPtr {
+					if _, isBasic := ptr.Elem().Underlying().(*types.Basic); isBasic {
+						writef("\tx := *src.%s[i]", fname)
+						writef("\tdst.%s[i] = &x", fname)
+					} else {
+						writef("\tdst.%s[i] = src.%s[i].Clone()", fname, fname)
+					}
 				} else {
 					writef("\tdst.%s[i] = *src.%s[i].Clone()", fname, fname)
 				}
@@ -196,7 +144,7 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
 				writef("dst.%s = src.%s.Clone()", fname, fname)
 				continue
 			}
-			n := importedName(ft.Elem())
+			n := it.QualifiedName(ft.Elem())
 			writef("if dst.%s != nil {", fname)
 			writef("\tdst.%s = new(%s)", fname, n)
 			writef("\t*dst.%s = *src.%s", fname, fname)
@@ -206,9 +154,9 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
 			writef("}")
 		case *types.Map:
 			writef("if dst.%s != nil {", fname)
-			writef("\tdst.%s = map[%s]%s{}", fname, importedName(ft.Key()), importedName(ft.Elem()))
+			writef("\tdst.%s = map[%s]%s{}", fname, it.QualifiedName(ft.Key()), it.QualifiedName(ft.Elem()))
 			if sliceType, isSlice := ft.Elem().(*types.Slice); isSlice {
-				n := importedName(sliceType.Elem())
+				n := it.QualifiedName(sliceType.Elem())
 				writef("\tfor k := range src.%s {", fname)
 				// use zero-length slice instead of nil to ensure
 				// the key is always copied.
@@ -231,9 +179,10 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
 	writef("return dst")
 	fmt.Fprintf(buf, "}\n\n")
 
-	buf.Write(codegen.AssertStructUnchanged(t, thisPkg, name, "Clone", imports))
+	buf.Write(codegen.AssertStructUnchanged(t, name, "Clone", it))
 }
 
+// hasBasicUnderlying reports true when typ.Underlying() is a slice or a map.
 func hasBasicUnderlying(typ types.Type) bool {
 	switch typ.Underlying().(type) {
 	case *types.Slice, *types.Map:

cmd/derper/bootstrap_dns.go

@@ -12,14 +12,11 @@ import (
 	"net"
 	"net/http"
 	"strings"
-	"sync"
+	"sync/atomic"
 	"time"
 )
 
-var (
-	dnsMu    sync.Mutex
-	dnsCache = map[string][]net.IP{}
-)
+var dnsCache atomic.Value // of []byte
 
 var bootstrapDNSRequests = expvar.NewInt("counter_bootstrap_dns_requests")
 
@@ -37,6 +34,7 @@ func refreshBootstrapDNS() {
 	if *bootstrapDNS == "" {
 		return
 	}
+	dnsEntries := make(map[string][]net.IP)
 	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
 	defer cancel()
 	names := strings.Split(*bootstrapDNS, ",")
@@ -47,23 +45,23 @@ func refreshBootstrapDNS() {
 			log.Printf("bootstrap DNS lookup %q: %v", name, err)
 			continue
 		}
-		dnsMu.Lock()
-		dnsCache[name] = addrs
-		dnsMu.Unlock()
+		dnsEntries[name] = addrs
 	}
+	j, err := json.MarshalIndent(dnsEntries, "", "\t")
+	if err != nil {
+		// leave the old values in place
+		return
+	}
+	dnsCache.Store(j)
 }
 
 func handleBootstrapDNS(w http.ResponseWriter, r *http.Request) {
 	bootstrapDNSRequests.Add(1)
-	dnsMu.Lock()
-	j, err := json.MarshalIndent(dnsCache, "", "\t")
-	dnsMu.Unlock()
-	if err != nil {
-		log.Printf("bootstrap DNS JSON: %v", err)
-		http.Error(w, "JSON marshal error", 500)
-		return
-	}
-
 	w.Header().Set("Content-Type", "application/json")
+	j, _ := dnsCache.Load().([]byte)
+	// Bootstrap DNS requests occur cross-regions,
+	// and are randomized per request,
+	// so keeping a connection open is pointlessly expensive.
+	w.Header().Set("Connection", "close")
 	w.Write(j)
 }

cmd/derper/bootstrap_dns_test.go

@@ -0,0 +1,35 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"net/http"
+	"testing"
+)
+
+func BenchmarkHandleBootstrapDNS(b *testing.B) {
+	prev := *bootstrapDNS
+	*bootstrapDNS = "log.tailscale.io,login.tailscale.com,controlplane.tailscale.com,login.us.tailscale.com"
+	defer func() {
+		*bootstrapDNS = prev
+	}()
+	refreshBootstrapDNS()
+	w := new(bitbucketResponseWriter)
+	b.ReportAllocs()
+	b.ResetTimer()
+	b.RunParallel(func(b *testing.PB) {
+		for b.Next() {
+			handleBootstrapDNS(w, nil)
+		}
+	})
+}
+
+type bitbucketResponseWriter struct{}
+
+func (b *bitbucketResponseWriter) Header() http.Header { return make(http.Header) }
+
+func (b *bitbucketResponseWriter) Write(p []byte) (int, error) { return len(p), nil }
+
+func (b *bitbucketResponseWriter) WriteHeader(statusCode int) {}

cmd/derper/derper.go

@@ -16,6 +16,7 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
+	"math"
 	"net"
 	"net/http"
 	"os"
@@ -24,10 +25,10 @@ import (
 	"strings"
 	"time"
 
+	"golang.org/x/time/rate"
 	"tailscale.com/atomicfile"
 	"tailscale.com/derp"
 	"tailscale.com/derp/derphttp"
-	"tailscale.com/logpolicy"
 	"tailscale.com/metrics"
 	"tailscale.com/net/stun"
 	"tailscale.com/tsweb"
@@ -35,20 +36,23 @@ import (
 )
 
 var (
-	dev           = flag.Bool("dev", false, "run in localhost development mode")
-	addr          = flag.String("a", ":443", "server HTTPS listen address, in form \":port\", \"ip:port\", or for IPv6 \"[ip]:port\". If the IP is omitted, it defaults to all interfaces.")
-	httpPort      = flag.Int("http-port", 80, "The port on which to serve HTTP. Set to -1 to disable")
-	configPath    = flag.String("c", "", "config file path")
-	certMode      = flag.String("certmode", "letsencrypt", "mode for getting a cert. possible options: manual, letsencrypt")
-	certDir       = flag.String("certdir", tsweb.DefaultCertDir("derper-certs"), "directory to store LetsEncrypt certs, if addr's port is :443")
-	hostname      = flag.String("hostname", "derp.tailscale.com", "LetsEncrypt host name, if addr's port is :443")
-	logCollection = flag.String("logcollection", "", "If non-empty, logtail collection to log to")
-	runSTUN       = flag.Bool("stun", true, "whether to run a STUN server. It will bind to the same IP (if any) as the --addr flag value.")
+	dev        = flag.Bool("dev", false, "run in localhost development mode")
+	addr       = flag.String("a", ":443", "server HTTPS listen address, in form \":port\", \"ip:port\", or for IPv6 \"[ip]:port\". If the IP is omitted, it defaults to all interfaces.")
+	httpPort   = flag.Int("http-port", 80, "The port on which to serve HTTP. Set to -1 to disable. The listener is bound to the same IP (if any) as specified in the -a flag.")
+	stunPort   = flag.Int("stun-port", 3478, "The UDP port on which to serve STUN. The listener is bound to the same IP (if any) as specified in the -a flag.")
+	configPath = flag.String("c", "", "config file path")
+	certMode   = flag.String("certmode", "letsencrypt", "mode for getting a cert. possible options: manual, letsencrypt")
+	certDir    = flag.String("certdir", tsweb.DefaultCertDir("derper-certs"), "directory to store LetsEncrypt certs, if addr's port is :443")
+	hostname   = flag.String("hostname", "derp.tailscale.com", "LetsEncrypt host name, if addr's port is :443")
+	runSTUN    = flag.Bool("stun", true, "whether to run a STUN server. It will bind to the same IP (if any) as the --addr flag value.")
 
 	meshPSKFile   = flag.String("mesh-psk-file", defaultMeshPSKFile(), "if non-empty, path to file containing the mesh pre-shared key file. It should contain some hex string; whitespace is trimmed.")
 	meshWith      = flag.String("mesh-with", "", "optional comma-separated list of hostnames to mesh with; the server's own hostname can be in the list")
 	bootstrapDNS  = flag.String("bootstrap-dns-names", "", "optional comma-separated list of hostnames to make available at /bootstrap-dns")
 	verifyClients = flag.Bool("verify-clients", false, "verify clients to this DERP server through a local tailscaled instance.")
+
+	acceptConnLimit = flag.Float64("accept-connection-limit", math.Inf(+1), "rate limit for accepting new connection")
+	acceptConnBurst = flag.Int("accept-connection-burst", math.MaxInt, "burst limit for accepting new connection")
 )
 
 var (
@@ -129,7 +133,6 @@ func main() {
 	flag.Parse()
 
 	if *dev {
-		*logCollection = ""
 		*addr = ":3340" // above the keys DERP
 		log.Printf("Running in dev mode.")
 		tsweb.DevMode = true
@@ -140,12 +143,6 @@ func main() {
 		log.Fatalf("invalid server address: %v", err)
 	}
 
-	var logPol *logpolicy.Policy
-	if *logCollection != "" {
-		logPol = logpolicy.New(*logCollection)
-		log.SetOutput(logPol.Logtail)
-	}
-
 	cfg := loadConfig()
 
 	serveTLS := tsweb.IsProd443(*addr) || *certMode == "manual"
@@ -207,7 +204,7 @@ func main() {
 	debug.Handle("traffic", "Traffic check", http.HandlerFunc(s.ServeDebugTraffic))
 
 	if *runSTUN {
-		go serveSTUN(listenHost)
+		go serveSTUN(listenHost, *stunPort)
 	}
 
 	httpsrv := &http.Server{
@@ -296,7 +293,7 @@ func main() {
 				}
 			}()
 		}
-		err = httpsrv.ListenAndServeTLS("", "")
+		err = rateLimitedListenAndServeTLS(httpsrv)
 	} else {
 		log.Printf("derper: serving on %s", *addr)
 		err = httpsrv.ListenAndServe()
@@ -317,8 +314,8 @@ func probeHandler(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-func serveSTUN(host string) {
-	pc, err := net.ListenPacket("udp", net.JoinHostPort(host, "3478"))
+func serveSTUN(host string, port int) {
+	pc, err := net.ListenPacket("udp", net.JoinHostPort(host, fmt.Sprint(port)))
 	if err != nil {
 		log.Fatalf("failed to open STUN listener: %v", err)
 	}
@@ -390,3 +387,63 @@ func defaultMeshPSKFile() string {
 	}
 	return ""
 }
+
+func rateLimitedListenAndServeTLS(srv *http.Server) error {
+	addr := srv.Addr
+	if addr == "" {
+		addr = ":https"
+	}
+	ln, err := net.Listen("tcp", addr)
+	if err != nil {
+		return err
+	}
+	rln := newRateLimitedListener(ln, rate.Limit(*acceptConnLimit), *acceptConnBurst)
+	expvar.Publish("tls_listener", rln.ExpVar())
+	defer rln.Close()
+	return srv.ServeTLS(rln, "", "")
+}
+
+type rateLimitedListener struct {
+	// These are at the start of the struct to ensure 64-bit alignment
+	// on 32-bit architecture regardless of what other fields may exist
+	// in this package.
+	numAccepts expvar.Int // does not include number of rejects
+	numRejects expvar.Int
+
+	net.Listener
+
+	lim *rate.Limiter
+}
+
+func newRateLimitedListener(ln net.Listener, limit rate.Limit, burst int) *rateLimitedListener {
+	return &rateLimitedListener{Listener: ln, lim: rate.NewLimiter(limit, burst)}
+}
+
+func (l *rateLimitedListener) ExpVar() expvar.Var {
+	m := new(metrics.Set)
+	m.Set("counter_accepted_connections", &l.numAccepts)
+	m.Set("counter_rejected_connections", &l.numRejects)
+	return m
+}
+
+var errLimitedConn = errors.New("cannot accept connection; rate limited")
+
+func (l *rateLimitedListener) Accept() (net.Conn, error) {
+	// Even under a rate limited situation, we accept the connection immediately
+	// and close it, rather than being slow at accepting new connections.
+	// This provides two benefits: 1) it signals to the client that something
+	// is going on on the server, and 2) it prevents new connections from
+	// piling up and occupying resources in the OS kernel.
+	// The client will retry as needing (with backoffs in place).
+	cn, err := l.Listener.Accept()
+	if err != nil {
+		return nil, err
+	}
+	if !l.lim.Allow() {
+		l.numRejects.Add(1)
+		cn.Close()
+		return nil, errLimitedConn
+	}
+	l.numAccepts.Add(1)
+	return cn, nil
+}

cmd/derper/websocket.go

@@ -13,7 +13,6 @@ import (
 
 	"nhooyr.io/websocket"
 	"tailscale.com/derp"
-	"tailscale.com/derp/wsconn"
 )
 
 var counterWebSocketAccepts = expvar.NewInt("derp_websocket_accepts")
@@ -45,8 +44,8 @@ func addWebSocketSupport(s *derp.Server, base http.Handler) http.Handler {
 			return
 		}
 		counterWebSocketAccepts.Add(1)
-		wc := wsconn.New(c)
+		wc := websocket.NetConn(r.Context(), c, websocket.MessageBinary)
 		brw := bufio.NewReadWriter(bufio.NewReader(wc), bufio.NewWriter(wc))
-		s.Accept(wc, brw, r.RemoteAddr)
+		s.Accept(r.Context(), wc, brw, r.RemoteAddr)
 	})
 }

cmd/derpprobe/derpprobe.go

@@ -19,7 +19,9 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"os"
 	"sort"
+	"strings"
 	"sync"
 	"time"
 
@@ -54,7 +56,15 @@ var (
 
 func main() {
 	flag.Parse()
+
+	// proactively load the DERP map. Nothing terrible happens if this fails, so we ignore
+	// the error. The Slack bot will print a notification that the DERP map was empty.
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	_, _ = getDERPMap(ctx)
+
 	go probeLoop()
+	go slackLoop()
 	log.Fatal(http.ListenAndServe(*listen, http.HandlerFunc(serve)))
 }
 
@@ -68,11 +78,11 @@ type overallStatus struct {
 	good, bad []string
 }
 
-func (st *overallStatus) addBadf(format string, a ...interface{}) {
+func (st *overallStatus) addBadf(format string, a ...any) {
 	st.bad = append(st.bad, fmt.Sprintf(format, a...))
 }
 
-func (st *overallStatus) addGoodf(format string, a ...interface{}) {
+func (st *overallStatus) addGoodf(format string, a ...any) {
 	st.good = append(st.good, fmt.Sprintf(format, a...))
 }
 
@@ -138,10 +148,14 @@ func getOverallStatus() (o overallStatus) {
 func serve(w http.ResponseWriter, r *http.Request) {
 	st := getOverallStatus()
 	summary := "All good"
-	if len(st.bad) > 0 {
+	if (float64(len(st.bad)) / float64(len(st.bad)+len(st.good))) > 0.25 {
+		// This will generate an alert and page a human.
+		// It also ends up in Slack, but as part of the alert handling pipeline not
+		// because we generated a Slack notification from here.
 		w.WriteHeader(500)
 		summary = fmt.Sprintf("%d problems", len(st.bad))
 	}
+
 	io.WriteString(w, "<html><head><style>.bad { font-weight: bold; color: #700; }</style></head>\n")
 	fmt.Fprintf(w, "<body><h1>derp probe</h1>\n%s:<ul>", summary)
 	for _, s := range st.bad {
@@ -153,6 +167,71 @@ func serve(w http.ResponseWriter, r *http.Request) {
 	io.WriteString(w, "</ul></body></html>\n")
 }
 
+func notifySlack(text string) error {
+	type SlackRequestBody struct {
+		Text string `json:"text"`
+	}
+
+	slackBody, err := json.Marshal(SlackRequestBody{Text: text})
+	if err != nil {
+		return err
+	}
+
+	webhookUrl := os.Getenv("SLACK_WEBHOOK")
+	if webhookUrl == "" {
+		return errors.New("No SLACK_WEBHOOK configured")
+	}
+
+	req, err := http.NewRequest("POST", webhookUrl, bytes.NewReader(slackBody))
+	if err != nil {
+		return err
+	}
+	req.Header.Add("Content-Type", "application/json")
+
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return errors.New(resp.Status)
+	}
+
+	body, _ := io.ReadAll(resp.Body)
+	if string(body) != "ok" {
+		return errors.New("Non-ok response returned from Slack")
+	}
+	return nil
+}
+
+// We only page a human if it looks like there is a significant outage across multiple regions.
+// To Slack, we report all failures great and small.
+func slackLoop() {
+	inBadState := false
+	for {
+		time.Sleep(time.Second * 30)
+		st := getOverallStatus()
+
+		if len(st.bad) > 0 && !inBadState {
+			err := notifySlack(strings.Join(st.bad, "\n"))
+			if err == nil {
+				inBadState = true
+			} else {
+				log.Printf("%d problems, notify Slack failed: %v", len(st.bad), err)
+			}
+		}
+
+		if len(st.bad) == 0 && inBadState {
+			err := notifySlack("All DERPs recovered.")
+			if err == nil {
+				inBadState = false
+			}
+		}
+	}
+}
+
 func sortedRegions(dm *tailcfg.DERPMap) []*tailcfg.DERPRegion {
 	ret := make([]*tailcfg.DERPRegion, 0, len(dm.Regions))
 	for _, r := range dm.Regions {
@@ -347,7 +426,7 @@ func probeNodePair(ctx context.Context, dm *tailcfg.DERPMap, from, to *tailcfg.D
 	}
 
 	// Receive the random packet.
-	recvc := make(chan interface{}, 1) // either derp.ReceivedPacket or error
+	recvc := make(chan any, 1) // either derp.ReceivedPacket or error
 	go func() {
 		for {
 			m, err := toc.Recv()

cmd/gitops-pusher/.gitignore

@@ -0,0 +1 @@
+version-cache.json

cmd/gitops-pusher/README.md

@@ -0,0 +1,48 @@
+# gitops-pusher
+
+This is a small tool to help people achieve a
+[GitOps](https://about.gitlab.com/topics/gitops/) workflow with Tailscale ACL
+changes. This tool is intended to be used in a CI flow that looks like this:
+
+```yaml
+name: Tailscale ACL syncing
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  acls:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+      
+      - name: Setup Go environment
+        uses: actions/setup-go@v3.2.0
+        
+      - name: Install gitops-pusher
+        run: go install tailscale.com/cmd/gitops-pusher@latest
+              
+      - name: Deploy ACL
+        if: github.event_name == 'push'
+        env:
+          TS_API_KEY: ${{ secrets.TS_API_KEY }}
+          TS_TAILNET: ${{ secrets.TS_TAILNET }}
+        run: |
+          ~/go/bin/gitops-pusher --policy-file ./policy.hujson apply
+
+      - name: ACL tests
+        if: github.event_name == 'pull_request'
+        env:
+          TS_API_KEY: ${{ secrets.TS_API_KEY }}
+          TS_TAILNET: ${{ secrets.TS_TAILNET }}
+        run: |
+          ~/go/bin/gitops-pusher --policy-file ./policy.hujson test
+```
+
+Change the value of the `--policy-file` flag to point to the policy file on
+disk. Policy files should be in [HuJSON](https://github.com/tailscale/hujson)
+format.

cmd/gitops-pusher/cache.go

@@ -0,0 +1,67 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"encoding/json"
+	"os"
+)
+
+// Cache contains cached information about the last time this tool was run.
+//
+// This is serialized to a JSON file that should NOT be checked into git.
+// It should be managed with either CI cache tools or stored locally somehow. The
+// exact mechanism is irrelevant as long as it is consistent.
+//
+// This allows gitops-pusher to detect external ACL changes. I'm not sure what to
+// call this problem, so I've been calling it the "three version problem" in my
+// notes. The basic problem is that at any given time we only have two versions
+// of the ACL file at any given point. In order to check if there has been
+// tampering of the ACL files in the admin panel, we need to have a _third_ version
+// to compare against.
+//
+// In this case I am not storing the old ACL entirely (though that could be a
+// reasonable thing to add in the future), but only its sha256sum. This allows
+// us to detect if the shasum in control matches the shasum we expect, and if that
+// expectation fails, then we can react accordingly.
+type Cache struct {
+	PrevETag string // Stores the previous ETag of the ACL to allow
+}
+
+// Save persists the cache to a given file.
+func (c *Cache) Save(fname string) error {
+	os.Remove(fname)
+	fout, err := os.Create(fname)
+	if err != nil {
+		return err
+	}
+	defer fout.Close()
+
+	return json.NewEncoder(fout).Encode(c)
+}
+
+// LoadCache loads the cache from a given file.
+func LoadCache(fname string) (*Cache, error) {
+	var result Cache
+
+	fin, err := os.Open(fname)
+	if err != nil {
+		return nil, err
+	}
+	defer fin.Close()
+
+	err = json.NewDecoder(fin).Decode(&result)
+	if err != nil {
+		return nil, err
+	}
+
+	return &result, nil
+}
+
+// Shuck removes the first and last character of a string, analogous to
+// shucking off the husk of an ear of corn.
+func Shuck(s string) string {
+	return s[1 : len(s)-1]
+}

cmd/gitops-pusher/gitops-pusher.go

@@ -0,0 +1,373 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Command gitops-pusher allows users to use a GitOps flow for managing Tailscale ACLs.
+//
+// See README.md for more details.
+package main
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/peterbourgon/ff/v3/ffcli"
+	"github.com/tailscale/hujson"
+)
+
+var (
+	rootFlagSet  = flag.NewFlagSet("gitops-pusher", flag.ExitOnError)
+	policyFname  = rootFlagSet.String("policy-file", "./policy.hujson", "filename for policy file")
+	cacheFname   = rootFlagSet.String("cache-file", "./version-cache.json", "filename for the previous known version hash")
+	timeout      = rootFlagSet.Duration("timeout", 5*time.Minute, "timeout for the entire CI run")
+	githubSyntax = rootFlagSet.Bool("github-syntax", true, "use GitHub Action error syntax (https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-error-message)")
+
+	modifiedExternallyFailure = make(chan struct{}, 1)
+)
+
+func modifiedExternallyError() {
+	if *githubSyntax {
+		fmt.Printf("::error file=%s,line=1,col=1,title=Policy File Modified Externally::The policy file was modified externally in the admin console.\n", *policyFname)
+	} else {
+		fmt.Printf("The policy file was modified externally in the admin console.\n")
+	}
+	modifiedExternallyFailure <- struct{}{}
+}
+
+func apply(cache *Cache, tailnet, apiKey string) func(context.Context, []string) error {
+	return func(ctx context.Context, args []string) error {
+		controlEtag, err := getACLETag(ctx, tailnet, apiKey)
+		if err != nil {
+			return err
+		}
+
+		localEtag, err := sumFile(*policyFname)
+		if err != nil {
+			return err
+		}
+
+		if cache.PrevETag == "" {
+			log.Println("no previous etag found, assuming local file is correct and recording that")
+			cache.PrevETag = localEtag
+		}
+
+		log.Printf("control: %s", controlEtag)
+		log.Printf("local:   %s", localEtag)
+		log.Printf("cache:   %s", cache.PrevETag)
+
+		if cache.PrevETag != controlEtag {
+			modifiedExternallyError()
+		}
+
+		if controlEtag == localEtag {
+			cache.PrevETag = localEtag
+			log.Println("no update needed, doing nothing")
+			return nil
+		}
+
+		if err := applyNewACL(ctx, tailnet, apiKey, *policyFname, controlEtag); err != nil {
+			return err
+		}
+
+		cache.PrevETag = localEtag
+
+		return nil
+	}
+}
+
+func test(cache *Cache, tailnet, apiKey string) func(context.Context, []string) error {
+	return func(ctx context.Context, args []string) error {
+		controlEtag, err := getACLETag(ctx, tailnet, apiKey)
+		if err != nil {
+			return err
+		}
+
+		localEtag, err := sumFile(*policyFname)
+		if err != nil {
+			return err
+		}
+
+		if cache.PrevETag == "" {
+			log.Println("no previous etag found, assuming local file is correct and recording that")
+			cache.PrevETag = localEtag
+		}
+
+		log.Printf("control: %s", controlEtag)
+		log.Printf("local:   %s", localEtag)
+		log.Printf("cache:   %s", cache.PrevETag)
+
+		if cache.PrevETag != controlEtag {
+			modifiedExternallyError()
+		}
+
+		if controlEtag == localEtag {
+			log.Println("no updates found, doing nothing")
+			return nil
+		}
+
+		if err := testNewACLs(ctx, tailnet, apiKey, *policyFname); err != nil {
+			return err
+		}
+		return nil
+	}
+}
+
+func getChecksums(cache *Cache, tailnet, apiKey string) func(context.Context, []string) error {
+	return func(ctx context.Context, args []string) error {
+		controlEtag, err := getACLETag(ctx, tailnet, apiKey)
+		if err != nil {
+			return err
+		}
+
+		localEtag, err := sumFile(*policyFname)
+		if err != nil {
+			return err
+		}
+
+		if cache.PrevETag == "" {
+			log.Println("no previous etag found, assuming local file is correct and recording that")
+			cache.PrevETag = Shuck(localEtag)
+		}
+
+		log.Printf("control: %s", controlEtag)
+		log.Printf("local:   %s", localEtag)
+		log.Printf("cache:   %s", cache.PrevETag)
+
+		return nil
+	}
+}
+
+func main() {
+	tailnet, ok := os.LookupEnv("TS_TAILNET")
+	if !ok {
+		log.Fatal("set envvar TS_TAILNET to your tailnet's name")
+	}
+	apiKey, ok := os.LookupEnv("TS_API_KEY")
+	if !ok {
+		log.Fatal("set envvar TS_API_KEY to your Tailscale API key")
+	}
+	cache, err := LoadCache(*cacheFname)
+	if err != nil {
+		if os.IsNotExist(err) {
+			cache = &Cache{}
+		} else {
+			log.Fatalf("error loading cache: %v", err)
+		}
+	}
+	defer cache.Save(*cacheFname)
+
+	applyCmd := &ffcli.Command{
+		Name:       "apply",
+		ShortUsage: "gitops-pusher [options] apply",
+		ShortHelp:  "Pushes changes to CONTROL",
+		LongHelp:   `Pushes changes to CONTROL`,
+		Exec:       apply(cache, tailnet, apiKey),
+	}
+
+	testCmd := &ffcli.Command{
+		Name:       "test",
+		ShortUsage: "gitops-pusher [options] test",
+		ShortHelp:  "Tests ACL changes",
+		LongHelp:   "Tests ACL changes",
+		Exec:       test(cache, tailnet, apiKey),
+	}
+
+	cksumCmd := &ffcli.Command{
+		Name:       "checksum",
+		ShortUsage: "Shows checksums of ACL files",
+		ShortHelp:  "Fetch checksum of CONTROL's ACL and the local ACL for comparison",
+		LongHelp:   "Fetch checksum of CONTROL's ACL and the local ACL for comparison",
+		Exec:       getChecksums(cache, tailnet, apiKey),
+	}
+
+	root := &ffcli.Command{
+		ShortUsage:  "gitops-pusher [options] <command>",
+		ShortHelp:   "Push Tailscale ACLs to CONTROL using a GitOps workflow",
+		Subcommands: []*ffcli.Command{applyCmd, cksumCmd, testCmd},
+		FlagSet:     rootFlagSet,
+	}
+
+	if err := root.Parse(os.Args[1:]); err != nil {
+		log.Fatal(err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), *timeout)
+	defer cancel()
+
+	if err := root.Run(ctx); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	if len(modifiedExternallyFailure) != 0 {
+		os.Exit(1)
+	}
+}
+
+func sumFile(fname string) (string, error) {
+	data, err := os.ReadFile(fname)
+	if err != nil {
+		return "", err
+	}
+
+	formatted, err := hujson.Format(data)
+	if err != nil {
+		return "", err
+	}
+
+	h := sha256.New()
+	_, err = h.Write(formatted)
+	if err != nil {
+		return "", err
+	}
+
+	return fmt.Sprintf("%x", h.Sum(nil)), nil
+}
+
+func applyNewACL(ctx context.Context, tailnet, apiKey, policyFname, oldEtag string) error {
+	fin, err := os.Open(policyFname)
+	if err != nil {
+		return err
+	}
+	defer fin.Close()
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, fmt.Sprintf("https://api.tailscale.com/api/v2/tailnet/%s/acl", tailnet), fin)
+	if err != nil {
+		return err
+	}
+
+	req.SetBasicAuth(apiKey, "")
+	req.Header.Set("Content-Type", "application/hujson")
+	req.Header.Set("If-Match", `"`+oldEtag+`"`)
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	got := resp.StatusCode
+	want := http.StatusOK
+	if got != want {
+		var ate ACLTestError
+		err := json.NewDecoder(resp.Body).Decode(&ate)
+		if err != nil {
+			return err
+		}
+
+		return ate
+	}
+
+	return nil
+}
+
+func testNewACLs(ctx context.Context, tailnet, apiKey, policyFname string) error {
+	fin, err := os.Open(policyFname)
+	if err != nil {
+		return err
+	}
+	defer fin.Close()
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, fmt.Sprintf("https://api.tailscale.com/api/v2/tailnet/%s/acl/validate", tailnet), fin)
+	if err != nil {
+		return err
+	}
+
+	req.SetBasicAuth(apiKey, "")
+	req.Header.Set("Content-Type", "application/hujson")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	var ate ACLTestError
+	err = json.NewDecoder(resp.Body).Decode(&ate)
+	if err != nil {
+		return err
+	}
+
+	if len(ate.Message) != 0 || len(ate.Data) != 0 {
+		return ate
+	}
+
+	got := resp.StatusCode
+	want := http.StatusOK
+	if got != want {
+		return fmt.Errorf("wanted HTTP status code %d but got %d", want, got)
+	}
+
+	return nil
+}
+
+var lineColMessageSplit = regexp.MustCompile(`line ([0-9]+), column ([0-9]+): (.*)$`)
+
+type ACLTestError struct {
+	Message string               `json:"message"`
+	Data    []ACLTestErrorDetail `json:"data"`
+}
+
+func (ate ACLTestError) Error() string {
+	var sb strings.Builder
+
+	if *githubSyntax && lineColMessageSplit.MatchString(ate.Message) {
+		sp := lineColMessageSplit.FindStringSubmatch(ate.Message)
+
+		line := sp[1]
+		col := sp[2]
+		msg := sp[3]
+
+		fmt.Fprintf(&sb, "::error file=%s,line=%s,col=%s::%s", *policyFname, line, col, msg)
+	} else {
+		fmt.Fprintln(&sb, ate.Message)
+	}
+	fmt.Fprintln(&sb)
+
+	for _, data := range ate.Data {
+		fmt.Fprintf(&sb, "For user %s:\n", data.User)
+		for _, err := range data.Errors {
+			fmt.Fprintf(&sb, "- %s\n", err)
+		}
+	}
+
+	return sb.String()
+}
+
+type ACLTestErrorDetail struct {
+	User   string   `json:"user"`
+	Errors []string `json:"errors"`
+}
+
+func getACLETag(ctx context.Context, tailnet, apiKey string) (string, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, fmt.Sprintf("https://api.tailscale.com/api/v2/tailnet/%s/acl", tailnet), nil)
+	if err != nil {
+		return "", err
+	}
+
+	req.SetBasicAuth(apiKey, "")
+	req.Header.Set("Accept", "application/hujson")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	got := resp.StatusCode
+	want := http.StatusOK
+	if got != want {
+		return "", fmt.Errorf("wanted HTTP status code %d but got %d", want, got)
+	}
+
+	return Shuck(resp.Header.Get("ETag")), nil
+}

cmd/hello/hello.go

@@ -135,13 +135,13 @@ func tailscaleIP(who *apitype.WhoIsResponse) string {
 		return ""
 	}
 	for _, nodeIP := range who.Node.Addresses {
-		if nodeIP.IP().Is4() && nodeIP.IsSingleIP() {
-			return nodeIP.IP().String()
+		if nodeIP.Addr().Is4() && nodeIP.IsSingleIP() {
+			return nodeIP.Addr().String()
 		}
 	}
 	for _, nodeIP := range who.Node.Addresses {
 		if nodeIP.IsSingleIP() {
-			return nodeIP.IP().String()
+			return nodeIP.Addr().String()
 		}
 	}
 	return ""
@@ -196,7 +196,7 @@ func root(w http.ResponseWriter, r *http.Request) {
 			LoginName:     who.UserProfile.LoginName,
 			ProfilePicURL: who.UserProfile.ProfilePicURL,
 			MachineName:   firstLabel(who.Node.ComputedName),
-			MachineOS:     who.Node.Hostinfo.OS,
+			MachineOS:     who.Node.Hostinfo.OS(),
 			IP:            tailscaleIP(who),
 		}
 	}
@@ -206,8 +206,6 @@ func root(w http.ResponseWriter, r *http.Request) {
 
 // firstLabel s up until the first period, if any.
 func firstLabel(s string) string {
-	if i := strings.Index(s, "."); i != -1 {
-		return s[:i]
-	}
+	s, _, _ = strings.Cut(s, ".")
 	return s
 }

cmd/mkpkg/main.go

@@ -6,6 +6,7 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"log"
 	"os"
@@ -14,7 +15,6 @@ import (
 	"github.com/goreleaser/nfpm"
 	_ "github.com/goreleaser/nfpm/deb"
 	_ "github.com/goreleaser/nfpm/rpm"
-	"github.com/pborman/getopt"
 )
 
 // parseFiles parses a comma-separated list of colon-separated pairs
@@ -44,19 +44,21 @@ func parseEmptyDirs(s string) []string {
 }
 
 func main() {
-	out := getopt.StringLong("out", 'o', "", "output file to write")
-	goarch := getopt.StringLong("arch", 'a', "amd64", "GOARCH this package is for")
-	pkgType := getopt.StringLong("type", 't', "deb", "type of package to build (deb or rpm)")
-	files := getopt.StringLong("files", 'F', "", "comma-separated list of files in src:dst form")
-	configFiles := getopt.StringLong("configs", 'C', "", "like --files, but for files marked as user-editable config files")
-	emptyDirs := getopt.StringLong("emptydirs", 'E', "", "comma-separated list of empty directories")
-	version := getopt.StringLong("version", 0, "0.0.0", "version of the package")
-	postinst := getopt.StringLong("postinst", 0, "", "debian postinst script path")
-	prerm := getopt.StringLong("prerm", 0, "", "debian prerm script path")
-	postrm := getopt.StringLong("postrm", 0, "", "debian postrm script path")
-	replaces := getopt.StringLong("replaces", 0, "", "package which this package replaces, if any")
-	depends := getopt.StringLong("depends", 0, "", "comma-separated list of packages this package depends on")
-	getopt.Parse()
+	out := flag.String("out", "", "output file to write")
+	name := flag.String("name", "tailscale", "package name")
+	description := flag.String("description", "The easiest, most secure, cross platform way to use WireGuard + oauth2 + 2FA/SSO", "package description")
+	goarch := flag.String("arch", "amd64", "GOARCH this package is for")
+	pkgType := flag.String("type", "deb", "type of package to build (deb or rpm)")
+	files := flag.String("files", "", "comma-separated list of files in src:dst form")
+	configFiles := flag.String("configs", "", "like --files, but for files marked as user-editable config files")
+	emptyDirs := flag.String("emptydirs", "", "comma-separated list of empty directories")
+	version := flag.String("version", "0.0.0", "version of the package")
+	postinst := flag.String("postinst", "", "debian postinst script path")
+	prerm := flag.String("prerm", "", "debian prerm script path")
+	postrm := flag.String("postrm", "", "debian postrm script path")
+	replaces := flag.String("replaces", "", "package which this package replaces, if any")
+	depends := flag.String("depends", "", "comma-separated list of packages this package depends on")
+	flag.Parse()
 
 	filesMap, err := parseFiles(*files)
 	if err != nil {
@@ -68,12 +70,12 @@ func main() {
 	}
 	emptyDirList := parseEmptyDirs(*emptyDirs)
 	info := nfpm.WithDefaults(&nfpm.Info{
-		Name:        "tailscale",
+		Name:        *name,
 		Arch:        *goarch,
 		Platform:    "linux",
 		Version:     *version,
 		Maintainer:  "Tailscale Inc <info@tailscale.com>",
-		Description: "The easiest, most secure, cross platform way to use WireGuard + oauth2 + 2FA/SSO",
+		Description: *description,
 		Homepage:    "https://www.tailscale.com",
 		License:     "MIT",
 		Overridables: nfpm.Overridables{

cmd/nginx-auth/.gitignore

@@ -0,0 +1,4 @@
+nga.sock
+*.deb
+*.rpm
+tailscale.nginx-auth

cmd/nginx-auth/README.md

@@ -0,0 +1,157 @@
+# nginx-auth
+
+This is a tool that allows users to use Tailscale Whois authentication with
+NGINX as a reverse proxy. This allows users that already have a bunch of
+services hosted on an internal NGINX server to point those domains to the
+Tailscale IP of the NGINX server and then seamlessly use Tailscale for
+authentication.
+
+Many thanks to [@zrail](https://twitter.com/zrail/status/1511788463586222087) on
+Twitter for introducing the basic idea and offering some sample code. This
+program is based on that sample code with security enhancements. Namely:
+
+* This listens over a UNIX socket instead of a TCP socket, to prevent
+  leakage to the network
+* This uses systemd socket activation so that systemd owns the socket
+  and can then lock down the service to the bare minimum required to do
+  its job without having to worry about dropping permissions
+* This provides additional information in HTTP response headers that can
+  be useful for integrating with various services
+
+## Configuration
+
+In order to protect a service with this tool, do the following in the respective
+`server` block:
+
+Create an authentication location with the `internal` flag set:
+
+```nginx
+location /auth {
+  internal;
+
+  proxy_pass http://unix:/run/tailscale.nginx-auth.sock;
+  proxy_pass_request_body off;
+
+  proxy_set_header Host $http_host;
+  proxy_set_header Remote-Addr $remote_addr;
+  proxy_set_header Remote-Port $remote_port;
+  proxy_set_header Original-URI $request_uri;
+}
+```
+
+Then add the following to the `location /` block:
+
+```
+auth_request /auth;
+auth_request_set $auth_user $upstream_http_tailscale_user;
+auth_request_set $auth_name $upstream_http_tailscale_name;
+auth_request_set $auth_login $upstream_http_tailscale_login;
+auth_request_set $auth_tailnet $upstream_http_tailscale_tailnet;
+auth_request_set $auth_profile_picture $upstream_http_tailscale_profile_picture;
+
+proxy_set_header X-Webauth-User "$auth_user";
+proxy_set_header X-Webauth-Name "$auth_name";
+proxy_set_header X-Webauth-Login "$auth_login";
+proxy_set_header X-Webauth-Tailnet "$auth_tailnet";
+proxy_set_header X-Webauth-Profile-Picture "$auth_profile_picture";
+```
+
+When this configuration is used with a Go HTTP handler such as this:
+
+```go
+http.HandlerFunc(func (w http.ResponseWriter, r *http.Request) {
+	e := json.NewEncoder(w)
+	e.SetIndent("", "  ")
+	e.Encode(r.Header)
+})
+```
+
+You will get output like this:
+
+```json
+{
+  "Accept": [
+    "*/*"
+  ],
+  "Connection": [
+    "upgrade"
+  ],
+  "User-Agent": [
+    "curl/7.82.0"
+  ],
+  "X-Webauth-Login": [
+    "Xe"
+  ],
+  "X-Webauth-Name": [
+    "Xe Iaso"
+  ],
+  "X-Webauth-Profile-Picture": [
+    "https://avatars.githubusercontent.com/u/529003?v=4"
+  ],
+  "X-Webauth-Tailnet": [
+    "cetacean.org.github"
+  ]
+  "X-Webauth-User": [
+    "Xe@github"
+  ]
+}
+```
+
+## Headers
+
+The authentication service provides the following headers to decorate your
+proxied requests:
+
+| Header                      | Example Value                                                      | Description                                                                   |
+| :------                     | :--------------                                                    | :----------                                                                   |
+| `Tailscale-User`            | `azurediamond@hunter2.net`                                         | The Tailscale username the remote machine is logged in as in user@host form   |
+| `Tailscale-Login`           | `azurediamond`                                                     | The user portion of the Tailscale username the remote machine is logged in as |
+| `Tailscale-Name`            | `Azure Diamond`                                                    | The "real name" of the Tailscale user the machine is logged in as             |
+| `Tailscale-Profile-Picture` | `https://i.kym-cdn.com/photos/images/newsfeed/001/065/963/ae0.png` | The profile picture provided by the Identity Provider your tailnet uses       |
+| `Tailscale-Tailnet`          | `hunter2.net`                                       | The tailnet name                                                              |
+
+Most of the time you can set `X-Webauth-User` to the contents of the
+`Tailscale-User` header, but some services may not accept a username with an `@`
+symbol in it. If this is the case, set `X-Webauth-User` to the `Tailscale-Login`
+header.
+
+The `Tailscale-Tailnet` header can help you identify which tailnet the session
+is coming from. If you are using node sharing, this can help you make sure that
+you aren't giving administrative access to people outside your tailnet.
+
+### Allow Requests From Only One Tailnet
+
+If you want to prevent node sharing from allowing users to access a service, add
+the `Expected-Tailnet` header to your auth request:
+
+```nginx
+location /auth {
+  # ...
+  proxy_set_header Expected-Tailnet "tailscale.com";
+}
+```
+
+If a user from a different tailnet tries to use that service, this will return a
+generic "forbidden" error page:
+
+```html
+<html>
+<head><title>403 Forbidden</title></head>
+<body>
+<center><h1>403 Forbidden</h1></center>
+<hr><center>nginx/1.18.0 (Ubuntu)</center>
+</body>
+</html>
+```
+
+## Building
+
+Install `cmd/mkpkg`:
+
+```
+cd .. && go install ./mkpkg
+```
+
+Then run `./mkdeb.sh`. It will emit a `.deb` and `.rpm` package for amd64
+machines (Linux uname flag: `x86_64`). You can add these to your deployment
+methods as you see fit.

cmd/nginx-auth/deb/postinst.sh

@@ -0,0 +1,14 @@
+if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ] || [ "$1" = "abort-deconfigure" ] || [ "$1" = "abort-remove" ] ; then
+	  deb-systemd-helper unmask 'tailscale.nginx-auth.socket' >/dev/null || true
+	  if deb-systemd-helper --quiet was-enabled 'tailscale.nginx-auth.socket'; then
+		    deb-systemd-helper enable 'tailscale.nginx-auth.socket' >/dev/null || true
+	  else
+		    deb-systemd-helper update-state 'tailscale.nginx-auth.socket' >/dev/null || true
+	  fi
+
+    if systemctl is-active tailscale.nginx-auth.socket >/dev/null; then
+        systemctl --system daemon-reload >/dev/null || true
+        deb-systemd-invoke stop 'tailscale.nginx-auth.service' >/dev/null || true
+        deb-systemd-invoke restart 'tailscale.nginx-auth.socket' >/dev/null || true
+    fi
+fi

cmd/nginx-auth/deb/postrm.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+set -e
+if [ -d /run/systemd/system ] ; then
+	  systemctl --system daemon-reload >/dev/null || true
+fi
+
+if [ -x "/usr/bin/deb-systemd-helper" ]; then
+    if [ "$1" = "remove" ]; then
+		    deb-systemd-helper mask 'tailscale.nginx-auth.socket' >/dev/null || true
+		    deb-systemd-helper mask 'tailscale.nginx-auth.service' >/dev/null || true
+	  fi
+
+    if [ "$1" = "purge" ]; then
+		    deb-systemd-helper purge 'tailscale.nginx-auth.socket' >/dev/null || true
+		    deb-systemd-helper unmask 'tailscale.nginx-auth.socket' >/dev/null || true
+		    deb-systemd-helper purge 'tailscale.nginx-auth.service' >/dev/null || true
+		    deb-systemd-helper unmask 'tailscale.nginx-auth.service' >/dev/null || true
+	  fi
+fi

cmd/nginx-auth/deb/prerm.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+set -e
+if [ "$1" = "remove" ]; then
+	  if [ -d /run/systemd/system ]; then
+		    deb-systemd-invoke stop 'tailscale.nginx-auth.service' >/dev/null || true
+		    deb-systemd-invoke stop 'tailscale.nginx-auth.socket' >/dev/null || true
+	  fi
+fi

cmd/nginx-auth/mkdeb.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+
+set -e
+
+CGO_ENABLED=0 GOARCH=amd64 GOOS=linux go build -o tailscale.nginx-auth .
+
+VERSION=0.1.1
+
+mkpkg \
+    --out=tailscale-nginx-auth-${VERSION}-amd64.deb \
+    --name=tailscale-nginx-auth \
+    --version=${VERSION} \
+    --type=deb \
+    --arch=amd64 \
+    --postinst=deb/postinst.sh \
+    --postrm=deb/postrm.sh \
+    --prerm=deb/prerm.sh \
+    --description="Tailscale NGINX authentication protocol handler" \
+    --files=./tailscale.nginx-auth:/usr/sbin/tailscale.nginx-auth,./tailscale.nginx-auth.socket:/lib/systemd/system/tailscale.nginx-auth.socket,./tailscale.nginx-auth.service:/lib/systemd/system/tailscale.nginx-auth.service,./README.md:/usr/share/tailscale/nginx-auth/README.md
+
+mkpkg \
+    --out=tailscale-nginx-auth-${VERSION}-amd64.rpm \
+    --name=tailscale-nginx-auth \
+    --version=${VERSION} \
+    --type=rpm \
+    --arch=amd64 \
+    --postinst=rpm/postinst.sh \
+    --postrm=rpm/postrm.sh \
+    --prerm=rpm/prerm.sh \
+    --description="Tailscale NGINX authentication protocol handler" \
+    --files=./tailscale.nginx-auth:/usr/sbin/tailscale.nginx-auth,./tailscale.nginx-auth.socket:/lib/systemd/system/tailscale.nginx-auth.socket,./tailscale.nginx-auth.service:/lib/systemd/system/tailscale.nginx-auth.service,./README.md:/usr/share/tailscale/nginx-auth/README.md

cmd/nginx-auth/nginx-auth.go

@@ -0,0 +1,127 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux
+
+// Command nginx-auth is a tool that allows users to use Tailscale Whois
+// authentication with NGINX as a reverse proxy. This allows users that
+// already have a bunch of services hosted on an internal NGINX server
+// to point those domains to the Tailscale IP of the NGINX server and
+// then seamlessly use Tailscale for authentication.
+package main
+
+import (
+	"flag"
+	"log"
+	"net"
+	"net/http"
+	"net/netip"
+	"net/url"
+	"os"
+	"strings"
+
+	"github.com/coreos/go-systemd/activation"
+	"tailscale.com/client/tailscale"
+)
+
+var (
+	sockPath = flag.String("sockpath", "", "the filesystem path for the unix socket this service exposes")
+)
+
+func main() {
+	flag.Parse()
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		remoteHost := r.Header.Get("Remote-Addr")
+		remotePort := r.Header.Get("Remote-Port")
+		if remoteHost == "" || remotePort == "" {
+			w.WriteHeader(http.StatusBadRequest)
+			log.Println("set Remote-Addr to $remote_addr and Remote-Port to $remote_port in your nginx config")
+			return
+		}
+
+		remoteAddrStr := net.JoinHostPort(remoteHost, remotePort)
+		remoteAddr, err := netip.ParseAddrPort(remoteAddrStr)
+		if err != nil {
+			w.WriteHeader(http.StatusUnauthorized)
+			log.Printf("remote address and port are not valid: %v", err)
+			return
+		}
+
+		info, err := tailscale.WhoIs(r.Context(), remoteAddr.String())
+		if err != nil {
+			w.WriteHeader(http.StatusUnauthorized)
+			log.Printf("can't look up %s: %v", remoteAddr, err)
+			return
+		}
+
+		if len(info.Node.Tags) != 0 {
+			w.WriteHeader(http.StatusForbidden)
+			log.Printf("node %s is tagged", info.Node.Hostinfo.Hostname())
+			return
+		}
+
+		_, tailnet, ok := strings.Cut(info.Node.Name, info.Node.ComputedName+".")
+		if !ok {
+			w.WriteHeader(http.StatusUnauthorized)
+			log.Printf("can't extract tailnet name from hostname %q", info.Node.Name)
+			return
+		}
+		tailnet, _, ok = strings.Cut(tailnet, ".beta.tailscale.net")
+		if !ok {
+			w.WriteHeader(http.StatusUnauthorized)
+			log.Printf("can't extract tailnet name from hostname %q", info.Node.Name)
+			return
+		}
+
+		if expectedTailnet := r.Header.Get("Expected-Tailnet"); expectedTailnet != "" && expectedTailnet != tailnet {
+			w.WriteHeader(http.StatusForbidden)
+			log.Printf("user is part of tailnet %s, wanted: %s", tailnet, url.QueryEscape(expectedTailnet))
+			return
+		}
+
+		h := w.Header()
+		h.Set("Tailscale-Login", strings.Split(info.UserProfile.LoginName, "@")[0])
+		h.Set("Tailscale-User", info.UserProfile.LoginName)
+		h.Set("Tailscale-Name", info.UserProfile.DisplayName)
+		h.Set("Tailscale-Profile-Picture", info.UserProfile.ProfilePicURL)
+		h.Set("Tailscale-Tailnet", tailnet)
+		w.WriteHeader(http.StatusNoContent)
+	})
+
+	if *sockPath != "" {
+		_ = os.Remove(*sockPath) // ignore error, this file may not already exist
+		ln, err := net.Listen("unix", *sockPath)
+		if err != nil {
+			log.Fatalf("can't listen on %s: %v", *sockPath, err)
+		}
+		defer ln.Close()
+
+		log.Printf("listening on %s", *sockPath)
+		log.Fatal(http.Serve(ln, mux))
+	}
+
+	listeners, err := activation.Listeners()
+	if err != nil {
+		log.Fatalf("no sockets passed to this service with systemd: %v", err)
+	}
+
+	// NOTE(Xe): normally you'd want to make a waitgroup here and then register
+	// each listener with it. In this case I want this to blow up horribly if
+	// any of the listeners stop working. systemd will restart it due to the
+	// socket activation at play.
+	//
+	// TL;DR: Let it crash, it will come back
+	for _, ln := range listeners {
+		go func(ln net.Listener) {
+			log.Printf("listening on %s", ln.Addr())
+			log.Fatal(http.Serve(ln, mux))
+		}(ln)
+	}
+
+	for {
+		select {}
+	}
+}

cmd/nginx-auth/rpm/postrm.sh

@@ -0,0 +1,9 @@
+# $1 == 0 for uninstallation.
+# $1 == 1 for removing old package during upgrade.
+
+systemctl daemon-reload >/dev/null 2>&1 || :
+if [ $1 -ge 1 ] ; then
+    # Package upgrade, not uninstall
+    systemctl stop tailscale.nginx-auth.service >/dev/null 2>&1 || :
+    systemctl try-restart tailscale.nginx-auth.socket >/dev/null 2>&1 || :
+fi

cmd/nginx-auth/rpm/prerm.sh

@@ -0,0 +1,9 @@
+# $1 == 0 for uninstallation.
+# $1 == 1 for removing old package during upgrade.
+
+if [ $1 -eq 0 ] ; then
+    # Package removal, not upgrade
+    systemctl --no-reload disable tailscale.nginx-auth.socket > /dev/null 2>&1 || :
+    systemctl stop tailscale.nginx-auth.socket > /dev/null 2>&1 || :
+    systemctl stop tailscale.nginx-auth.service > /dev/null 2>&1 || :
+fi

cmd/nginx-auth/tailscale.nginx-auth.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=Tailscale NGINX Authentication service
+After=nginx.service
+Wants=nginx.service
+
+[Service]
+ExecStart=/usr/sbin/tailscale.nginx-auth
+DynamicUser=yes
+
+[Install]
+WantedBy=default.target

cmd/nginx-auth/tailscale.nginx-auth.socket

@@ -0,0 +1,9 @@
+[Unit]
+Description=Tailscale NGINX Authentication socket
+PartOf=tailscale.nginx-auth.service
+
+[Socket]
+ListenStream=/var/run/tailscale.nginx-auth.sock
+
+[Install]
+WantedBy=sockets.target

cmd/printdep/printdep.go

@@ -19,10 +19,15 @@ import (
 var (
 	goToolchain    = flag.Bool("go", false, "print the supported Go toolchain git hash (a github.com/tailscale/go commit)")
 	goToolchainURL = flag.Bool("go-url", false, "print the URL to the tarball of the Tailscale Go toolchain")
+	alpine         = flag.Bool("alpine", false, "print the tag of alpine docker image")
 )
 
 func main() {
 	flag.Parse()
+	if *alpine {
+		fmt.Println(strings.TrimSpace(ts.AlpineDockerTag))
+		return
+	}
 	if *goToolchain {
 		fmt.Println(strings.TrimSpace(ts.GoToolchainRev))
 	}

cmd/proxy-to-grafana/proxy-to-grafana.go

@@ -0,0 +1,159 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// proxy-to-grafana is a reverse proxy which identifies users based on their
+// originating Tailscale identity and maps them to corresponding Grafana
+// users, creating them if needed.
+//
+// It uses Grafana's AuthProxy feature:
+// https://grafana.com/docs/grafana/latest/auth/auth-proxy/
+//
+// Set the TS_AUTHKEY environment variable to have this server automatically
+// join your tailnet, or look for the logged auth link on first start.
+//
+// Use this Grafana configuration to enable the auth proxy:
+//
+//     [auth.proxy]
+//     enabled = true
+//     header_name = X-WEBAUTH-USER
+//     header_property = username
+//     auto_sign_up = true
+//     whitelist = 127.0.0.1
+//     headers = Name:X-WEBAUTH-NAME
+//     enable_login_token = true
+package main
+
+import (
+	"context"
+	"crypto/tls"
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"strings"
+	"time"
+
+	"tailscale.com/client/tailscale"
+	"tailscale.com/tailcfg"
+	"tailscale.com/tsnet"
+)
+
+var (
+	hostname     = flag.String("hostname", "", "Tailscale hostname to serve on, used as the base name for MagicDNS or subdomain in your domain alias for HTTPS.")
+	backendAddr  = flag.String("backend-addr", "", "Address of the Grafana server served over HTTP, in host:port format. Typically localhost:nnnn.")
+	tailscaleDir = flag.String("state-dir", "./", "Alternate directory to use for Tailscale state storage. If empty, a default is used.")
+	useHTTPS     = flag.Bool("use-https", false, "Serve over HTTPS via your *.ts.net subdomain if enabled in Tailscale admin.")
+)
+
+func main() {
+	flag.Parse()
+	if *hostname == "" || strings.Contains(*hostname, ".") {
+		log.Fatal("missing or invalid --hostname")
+	}
+	if *backendAddr == "" {
+		log.Fatal("missing --backend-addr")
+	}
+	ts := &tsnet.Server{
+		Dir:      *tailscaleDir,
+		Hostname: *hostname,
+	}
+
+	// TODO(bradfitz,maisem): move this to a method on tsnet.Server probably.
+	if err := ts.Start(); err != nil {
+		log.Fatalf("Error starting tsnet.Server: %v", err)
+	}
+	localClient, _ := ts.LocalClient()
+
+	url, err := url.Parse(fmt.Sprintf("http://%s", *backendAddr))
+	if err != nil {
+		log.Fatalf("couldn't parse backend address: %v", err)
+	}
+
+	proxy := httputil.NewSingleHostReverseProxy(url)
+	originalDirector := proxy.Director
+	proxy.Director = func(req *http.Request) {
+		originalDirector(req)
+		modifyRequest(req, localClient)
+	}
+
+	var ln net.Listener
+	if *useHTTPS {
+		ln, err = ts.Listen("tcp", ":443")
+		ln = tls.NewListener(ln, &tls.Config{
+			GetCertificate: localClient.GetCertificate,
+		})
+
+		go func() {
+			// wait for tailscale to start before trying to fetch cert names
+			for i := 0; i < 60; i++ {
+				st, err := localClient.Status(context.Background())
+				if err != nil {
+					log.Printf("error retrieving tailscale status; retrying: %v", err)
+				} else {
+					log.Printf("tailscale status: %v", st.BackendState)
+					if st.BackendState == "Running" {
+						break
+					}
+				}
+				time.Sleep(time.Second)
+			}
+
+			l80, err := ts.Listen("tcp", ":80")
+			if err != nil {
+				log.Fatal(err)
+			}
+			name, ok := localClient.ExpandSNIName(context.Background(), *hostname)
+			if !ok {
+				log.Fatalf("can't get hostname for https redirect")
+			}
+			if err := http.Serve(l80, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				http.Redirect(w, r, fmt.Sprintf("https://%s", name), http.StatusMovedPermanently)
+			})); err != nil {
+				log.Fatal(err)
+			}
+		}()
+	} else {
+		ln, err = ts.Listen("tcp", ":80")
+	}
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Printf("proxy-to-grafana running at %v, proxying to %v", ln.Addr(), *backendAddr)
+	log.Fatal(http.Serve(ln, proxy))
+}
+
+func modifyRequest(req *http.Request, localClient *tailscale.LocalClient) {
+	// with enable_login_token set to true, we get a cookie that handles
+	// auth for paths that are not /login
+	if req.URL.Path != "/login" {
+		return
+	}
+
+	user, err := getTailscaleUser(req.Context(), localClient, req.RemoteAddr)
+	if err != nil {
+		log.Printf("error getting Tailscale user: %v", err)
+		return
+	}
+
+	req.Header.Set("X-Webauth-User", user.LoginName)
+	req.Header.Set("X-Webauth-Name", user.DisplayName)
+}
+
+func getTailscaleUser(ctx context.Context, localClient *tailscale.LocalClient, ipPort string) (*tailcfg.UserProfile, error) {
+	whois, err := localClient.WhoIs(ctx, ipPort)
+	if err != nil {
+		return nil, fmt.Errorf("failed to identify remote host: %w", err)
+	}
+	if len(whois.Node.Tags) != 0 {
+		return nil, fmt.Errorf("tagged nodes are not users")
+	}
+	if whois.UserProfile == nil || whois.UserProfile.LoginName == "" {
+		return nil, fmt.Errorf("failed to identify remote user")
+	}
+
+	return whois.UserProfile, nil
+}

cmd/tailscale/cli/bugreport.go

@@ -7,9 +7,9 @@ package cli
 import (
 	"context"
 	"errors"
+	"fmt"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"tailscale.com/client/tailscale"
 )
 
 var bugReportCmd = &ffcli.Command{
@@ -28,10 +28,10 @@ func runBugReport(ctx context.Context, args []string) error {
 	default:
 		return errors.New("unknown argumets")
 	}
-	logMarker, err := tailscale.BugReport(ctx, note)
+	logMarker, err := localClient.BugReport(ctx, note)
 	if err != nil {
 		return err
 	}
-	outln(logMarker)
+	fmt.Println(logMarker)
 	return nil
 }

cmd/tailscale/cli/cert.go

@@ -17,7 +17,6 @@ import (
 
 	"github.com/peterbourgon/ff/v3/ffcli"
 	"tailscale.com/atomicfile"
-	"tailscale.com/client/tailscale"
 	"tailscale.com/ipn"
 	"tailscale.com/version"
 )
@@ -28,7 +27,7 @@ var certCmd = &ffcli.Command{
 	ShortHelp:  "get TLS certs",
 	ShortUsage: "cert [flags] <domain>",
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("cert")
+		fs := flag.NewFlagSet("cert", flag.ExitOnError)
 		fs.StringVar(&certArgs.certFile, "cert-file", "", "output cert file or \"-\" for stdout; defaults to DOMAIN.crt if --cert-file and --key-file are both unset")
 		fs.StringVar(&certArgs.keyFile, "key-file", "", "output cert file or \"-\" for stdout; defaults to DOMAIN.key if --cert-file and --key-file are both unset")
 		fs.BoolVar(&certArgs.serve, "serve-demo", false, "if true, serve on port :443 using the cert as a demo, instead of writing out the files to disk")
@@ -46,11 +45,11 @@ func runCert(ctx context.Context, args []string) error {
 	if certArgs.serve {
 		s := &http.Server{
 			TLSConfig: &tls.Config{
-				GetCertificate: tailscale.GetCertificate,
+				GetCertificate: localClient.GetCertificate,
 			},
 			Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 				if r.TLS != nil && !strings.Contains(r.Host, ".") && r.Method == "GET" {
-					if v, ok := tailscale.ExpandSNIName(r.Context(), r.Host); ok {
+					if v, ok := localClient.ExpandSNIName(r.Context(), r.Host); ok {
 						http.Redirect(w, r, "https://"+v+r.URL.Path, http.StatusTemporaryRedirect)
 						return
 					}
@@ -64,7 +63,7 @@ func runCert(ctx context.Context, args []string) error {
 
 	if len(args) != 1 {
 		var hint bytes.Buffer
-		if st, err := tailscale.Status(ctx); err == nil {
+		if st, err := localClient.Status(ctx); err == nil {
 			if st.BackendState != ipn.Running.String() {
 				fmt.Fprintf(&hint, "\nTailscale is not running.\n")
 			} else if len(st.CertDomains) == 0 {
@@ -79,8 +78,8 @@ func runCert(ctx context.Context, args []string) error {
 	}
 	domain := args[0]
 
-	printf := func(format string, a ...interface{}) {
-		printf(format, a...)
+	printf := func(format string, a ...any) {
+		fmt.Printf(format, a...)
 	}
 	if certArgs.certFile == "-" || certArgs.keyFile == "-" {
 		printf = log.Printf
@@ -90,7 +89,7 @@ func runCert(ctx context.Context, args []string) error {
 		certArgs.certFile = domain + ".crt"
 		certArgs.keyFile = domain + ".key"
 	}
-	certPEM, keyPEM, err := tailscale.CertPair(ctx, domain)
+	certPEM, keyPEM, err := localClient.CertPair(ctx, domain)
 	if err != nil {
 		return err
 	}
@@ -139,7 +138,7 @@ func runCert(ctx context.Context, args []string) error {
 
 func writeIfChanged(filename string, contents []byte, mode os.FileMode) (changed bool, err error) {
 	if filename == "-" {
-		Stdout.Write(contents)
+		os.Stdout.Write(contents)
 		return false, nil
 	}
 	if old, err := os.ReadFile(filename); err == nil && bytes.Equal(contents, old) {

cmd/tailscale/cli/cli.go

@@ -25,28 +25,14 @@ import (
 
 	"github.com/peterbourgon/ff/v3/ffcli"
 	"tailscale.com/client/tailscale"
+	"tailscale.com/envknob"
 	"tailscale.com/ipn"
 	"tailscale.com/paths"
 	"tailscale.com/safesocket"
 	"tailscale.com/syncs"
+	"tailscale.com/version/distro"
 )
 
-var Stderr io.Writer = os.Stderr
-var Stdout io.Writer = os.Stdout
-
-func printf(format string, a ...interface{}) {
-	fmt.Fprintf(Stdout, format, a...)
-}
-
-// outln is like fmt.Println in the common case, except when Stdout is
-// changed (as in js/wasm).
-//
-// It's not named println because that looks like the Go built-in
-// which goes to stderr and formats slightly differently.
-func outln(a ...interface{}) {
-	fmt.Fprintln(Stdout, a...)
-}
-
 // ActLikeCLI reports whether a GUI application should act like the
 // CLI based on os.Args, GOOS, the context the process is running in
 // (pty, parent PID), etc.
@@ -93,18 +79,32 @@ func ActLikeCLI() bool {
 	return false
 }
 
-func newFlagSet(name string) *flag.FlagSet {
-	onError := flag.ExitOnError
-	if runtime.GOOS == "js" {
-		onError = flag.ContinueOnError
+// CleanUpArgs rewrites command line arguments for simplicity and backwards compatibility.
+// In particular, it rewrites --authkey to --auth-key.
+func CleanUpArgs(args []string) []string {
+	out := make([]string, 0, len(args))
+	for _, arg := range args {
+		// Rewrite --authkey to --auth-key, and --authkey=x to --auth-key=x,
+		// and the same for the -authkey variant.
+		switch {
+		case arg == "--authkey", arg == "-authkey":
+			arg = "--auth-key"
+		case strings.HasPrefix(arg, "--authkey="), strings.HasPrefix(arg, "-authkey="):
+			arg = strings.TrimLeft(arg, "-")
+			arg = strings.TrimPrefix(arg, "authkey=")
+			arg = "--auth-key=" + arg
+		}
+		out = append(out, arg)
 	}
-	fs := flag.NewFlagSet(name, onError)
-	fs.SetOutput(Stderr)
-	return fs
+	return out
 }
 
+var localClient tailscale.LocalClient
+
 // Run runs the CLI. The args do not include the binary name.
-func Run(args []string) error {
+func Run(args []string) (err error) {
+	args = CleanUpArgs(args)
+
 	if len(args) == 1 && (args[0] == "-V" || args[0] == "--version") {
 		args = []string{"version"}
 	}
@@ -112,11 +112,11 @@ func Run(args []string) error {
 	var warnOnce sync.Once
 	tailscale.SetVersionMismatchHandler(func(clientVer, serverVer string) {
 		warnOnce.Do(func() {
-			fmt.Fprintf(Stderr, "Warning: client version %q != tailscaled server version %q\n", clientVer, serverVer)
+			fmt.Fprintf(os.Stderr, "Warning: client version %q != tailscaled server version %q\n", clientVer, serverVer)
 		})
 	})
 
-	rootfs := newFlagSet("tailscale")
+	rootfs := flag.NewFlagSet("tailscale", flag.ExitOnError)
 	rootfs.StringVar(&rootArgs.socket, "socket", paths.DefaultTailscaledSocket(), "path to tailscaled's unix socket")
 
 	rootCmd := &ffcli.Command{
@@ -137,6 +137,8 @@ change in the future.
 			ipCmd,
 			statusCmd,
 			pingCmd,
+			ncCmd,
+			sshCmd,
 			versionCmd,
 			webCmd,
 			fileCmd,
@@ -150,11 +152,17 @@ change in the future.
 	for _, c := range rootCmd.Subcommands {
 		c.UsageFunc = usageFunc
 	}
+	if envknob.UseWIPCode() {
+		rootCmd.Subcommands = append(rootCmd.Subcommands, idTokenCmd)
+	}
 
 	// Don't advertise the debug command, but it exists.
 	if strSliceContains(args, "debug") {
 		rootCmd.Subcommands = append(rootCmd.Subcommands, debugCmd)
 	}
+	if runtime.GOOS == "linux" && distro.Get() == distro.Synology {
+		rootCmd.Subcommands = append(rootCmd.Subcommands, configureHostCmd)
+	}
 
 	if err := rootCmd.Parse(args); err != nil {
 		if errors.Is(err, flag.ErrHelp) {
@@ -163,14 +171,14 @@ change in the future.
 		return err
 	}
 
-	tailscale.TailscaledSocket = rootArgs.socket
+	localClient.Socket = rootArgs.socket
 	rootfs.Visit(func(f *flag.Flag) {
 		if f.Name == "socket" {
-			tailscale.TailscaledSocketSetExplicitly = true
+			localClient.UseSocketOnly = true
 		}
 	})
 
-	err := rootCmd.Run(context.Background())
+	err = rootCmd.Run(context.Background())
 	if tailscale.IsAccessDeniedError(err) && os.Getuid() != 0 && runtime.GOOS != "windows" {
 		return fmt.Errorf("%v\n\nUse 'sudo tailscale %s' or 'tailscale up --operator=$USER' to not require root.", err, strings.Join(args, " "))
 	}
@@ -180,7 +188,7 @@ change in the future.
 	return err
 }
 
-func fatalf(format string, a ...interface{}) {
+func fatalf(format string, a ...any) {
 	if Fatalf != nil {
 		Fatalf(format, a...)
 		return
@@ -190,7 +198,7 @@ func fatalf(format string, a ...interface{}) {
 }
 
 // Fatalf, if non-nil, is used instead of log.Fatalf.
-var Fatalf func(format string, a ...interface{})
+var Fatalf func(format string, a ...any)
 
 var rootArgs struct {
 	socket string

cmd/tailscale/cli/cli_test.go

@@ -9,16 +9,16 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
+	"net/netip"
 	"reflect"
 	"strings"
 	"testing"
 
+	qt "github.com/frankban/quicktest"
 	"github.com/google/go-cmp/cmp"
-	"inet.af/netaddr"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tstest"
-	"tailscale.com/types/key"
 	"tailscale.com/types/persist"
 	"tailscale.com/types/preftype"
 	"tailscale.com/version/distro"
@@ -56,7 +56,7 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 		flags    []string // argv to be parsed by FlagSet
 		curPrefs *ipn.Prefs
 
-		curExitNodeIP netaddr.IP
+		curExitNodeIP netip.Addr
 		curUser       string // os.Getenv("USER") on the client side
 		goos          string // empty means "linux"
 		distro        distro.Distro
@@ -152,10 +152,10 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				AllowSingleHosts: true,
 				CorpDNS:          true,
 				NetfilterMode:    preftype.NetfilterOn,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("10.0.42.0/24"),
-					netaddr.MustParseIPPrefix("0.0.0.0/0"),
-					netaddr.MustParseIPPrefix("::/0"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("10.0.42.0/24"),
+					netip.MustParsePrefix("0.0.0.0/0"),
+					netip.MustParsePrefix("::/0"),
 				},
 			},
 			want: accidentalUpPrefix + " --advertise-routes=10.0.42.0/24 --advertise-exit-node",
@@ -168,10 +168,10 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				AllowSingleHosts: true,
 				CorpDNS:          true,
 				NetfilterMode:    preftype.NetfilterOn,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("10.0.42.0/24"),
-					netaddr.MustParseIPPrefix("0.0.0.0/0"),
-					netaddr.MustParseIPPrefix("::/0"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("10.0.42.0/24"),
+					netip.MustParsePrefix("0.0.0.0/0"),
+					netip.MustParsePrefix("::/0"),
 				},
 			},
 			want: "",
@@ -184,10 +184,10 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				AllowSingleHosts: true,
 				CorpDNS:          true,
 				NetfilterMode:    preftype.NetfilterOn,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("10.0.42.0/24"),
-					netaddr.MustParseIPPrefix("0.0.0.0/0"),
-					netaddr.MustParseIPPrefix("::/0"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("10.0.42.0/24"),
+					netip.MustParsePrefix("0.0.0.0/0"),
+					netip.MustParsePrefix("::/0"),
 				},
 			},
 			want: "",
@@ -212,8 +212,8 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				CorpDNS:          true,
 				NetfilterMode:    preftype.NetfilterOn,
 
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("1.2.0.0/16"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("1.2.0.0/16"),
 				},
 			},
 			want: accidentalUpPrefix + " --advertise-exit-node --advertise-routes=1.2.0.0/16",
@@ -226,10 +226,10 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				AllowSingleHosts: true,
 				CorpDNS:          true,
 				NetfilterMode:    preftype.NetfilterOn,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("0.0.0.0/0"),
-					netaddr.MustParseIPPrefix("::/0"),
-					netaddr.MustParseIPPrefix("1.2.0.0/16"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("0.0.0.0/0"),
+					netip.MustParsePrefix("::/0"),
+					netip.MustParsePrefix("1.2.0.0/16"),
 				},
 			},
 			want: accidentalUpPrefix + " --advertise-exit-node --advertise-routes=1.2.0.0/16",
@@ -255,16 +255,16 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				ControlURL:       ipn.DefaultControlURL,
 				RouteAll:         true,
 				AllowSingleHosts: false,
-				ExitNodeIP:       netaddr.MustParseIP("100.64.5.6"),
+				ExitNodeIP:       netip.MustParseAddr("100.64.5.6"),
 				CorpDNS:          false,
 				ShieldsUp:        true,
 				AdvertiseTags:    []string{"tag:foo", "tag:bar"},
 				Hostname:         "myhostname",
 				ForceDaemon:      true,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("10.0.0.0/16"),
-					netaddr.MustParseIPPrefix("0.0.0.0/0"),
-					netaddr.MustParseIPPrefix("::/0"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("10.0.0.0/16"),
+					netip.MustParsePrefix("0.0.0.0/0"),
+					netip.MustParsePrefix("::/0"),
 				},
 				NetfilterMode: preftype.NetfilterNoDivert,
 				OperatorUser:  "alice",
@@ -280,14 +280,14 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				ControlURL:       ipn.DefaultControlURL,
 				RouteAll:         true,
 				AllowSingleHosts: false,
-				ExitNodeIP:       netaddr.MustParseIP("100.64.5.6"),
+				ExitNodeIP:       netip.MustParseAddr("100.64.5.6"),
 				CorpDNS:          false,
 				ShieldsUp:        true,
 				AdvertiseTags:    []string{"tag:foo", "tag:bar"},
 				Hostname:         "myhostname",
 				ForceDaemon:      true,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("10.0.0.0/16"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("10.0.0.0/16"),
 				},
 				NetfilterMode: preftype.NetfilterNoDivert,
 				OperatorUser:  "alice",
@@ -344,10 +344,10 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				AllowSingleHosts: true,
 				CorpDNS:          true,
 				NetfilterMode:    preftype.NetfilterOn,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("0.0.0.0/0"),
-					netaddr.MustParseIPPrefix("::/0"),
-					netaddr.MustParseIPPrefix("1.2.0.0/16"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("0.0.0.0/0"),
+					netip.MustParsePrefix("::/0"),
+					netip.MustParsePrefix("1.2.0.0/16"),
 				},
 			},
 			want: accidentalUpPrefix + " --operator=expbits --advertise-exit-node --advertise-routes=1.2.0.0/16",
@@ -360,10 +360,10 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				AllowSingleHosts: true,
 				CorpDNS:          true,
 				NetfilterMode:    preftype.NetfilterOn,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("0.0.0.0/0"),
-					netaddr.MustParseIPPrefix("::/0"),
-					netaddr.MustParseIPPrefix("1.2.0.0/16"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("0.0.0.0/0"),
+					netip.MustParsePrefix("::/0"),
+					netip.MustParsePrefix("1.2.0.0/16"),
 				},
 			},
 			want: accidentalUpPrefix + " --advertise-routes=1.2.0.0/16 --operator=expbits --advertise-exit-node",
@@ -380,7 +380,7 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 
 				Hostname: "foo",
 			},
-			want: accidentalUpPrefix + " --authkey=secretrand --force-reauth=false --reset --hostname=foo",
+			want: accidentalUpPrefix + " --auth-key=secretrand --force-reauth=false --reset --hostname=foo",
 		},
 		{
 			name:  "error_exit_node_omit_with_ip_pref",
@@ -391,14 +391,14 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 				CorpDNS:          true,
 				NetfilterMode:    preftype.NetfilterOn,
 
-				ExitNodeIP: netaddr.MustParseIP("100.64.5.4"),
+				ExitNodeIP: netip.MustParseAddr("100.64.5.4"),
 			},
 			want: accidentalUpPrefix + " --hostname=foo --exit-node=100.64.5.4",
 		},
 		{
 			name:          "error_exit_node_omit_with_id_pref",
 			flags:         []string{"--hostname=foo"},
-			curExitNodeIP: netaddr.MustParseIP("100.64.5.7"),
+			curExitNodeIP: netip.MustParseAddr("100.64.5.7"),
 			curPrefs: &ipn.Prefs{
 				ControlURL:       ipn.DefaultControlURL,
 				AllowSingleHosts: true,
@@ -412,7 +412,7 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 		{
 			name:          "error_exit_node_and_allow_lan_omit_with_id_pref", // Isue 3480
 			flags:         []string{"--hostname=foo"},
-			curExitNodeIP: netaddr.MustParseIP("100.2.3.4"),
+			curExitNodeIP: netip.MustParseAddr("100.2.3.4"),
 			curPrefs: &ipn.Prefs{
 				ControlURL:       ipn.DefaultControlURL,
 				AllowSingleHosts: true,
@@ -487,19 +487,22 @@ func TestCheckForAccidentalSettingReverts(t *testing.T) {
 			}
 			var upArgs upArgsT
 			flagSet := newUpFlagSet(goos, &upArgs)
-			flagSet.Parse(tt.flags)
+			flags := CleanUpArgs(tt.flags)
+			flagSet.Parse(flags)
 			newPrefs, err := prefsFromUpArgs(upArgs, t.Logf, new(ipnstate.Status), goos)
 			if err != nil {
 				t.Fatal(err)
 			}
-			applyImplicitPrefs(newPrefs, tt.curPrefs, tt.curUser)
-			var got string
-			if err := checkForAccidentalSettingReverts(newPrefs, tt.curPrefs, upCheckEnv{
+			upEnv := upCheckEnv{
 				goos:          goos,
 				flagSet:       flagSet,
 				curExitNodeIP: tt.curExitNodeIP,
 				distro:        tt.distro,
-			}); err != nil {
+				user:          tt.curUser,
+			}
+			applyImplicitPrefs(newPrefs, tt.curPrefs, upEnv)
+			var got string
+			if err := checkForAccidentalSettingReverts(newPrefs, tt.curPrefs, upEnv); err != nil {
 				got = err.Error()
 			}
 			if strings.TrimSpace(got) != tt.want {
@@ -559,9 +562,9 @@ func TestPrefsFromUpArgs(t *testing.T) {
 				WantRunning:      true,
 				AllowSingleHosts: true,
 				CorpDNS:          true,
-				AdvertiseRoutes: []netaddr.IPPrefix{
-					netaddr.MustParseIPPrefix("0.0.0.0/0"),
-					netaddr.MustParseIPPrefix("::/0"),
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("0.0.0.0/0"),
+					netip.MustParsePrefix("::/0"),
 				},
 				NetfilterMode: preftype.NetfilterOn,
 			},
@@ -628,9 +631,9 @@ func TestPrefsFromUpArgs(t *testing.T) {
 				exitNodeIP: "100.105.106.107",
 			},
 			st: &ipnstate.Status{
-				TailscaleIPs: []netaddr.IP{netaddr.MustParseIP("100.105.106.107")},
+				TailscaleIPs: []netip.Addr{netip.MustParseAddr("100.105.106.107")},
 			},
-			wantErr: `cannot use 100.105.106.107 as the exit node as it is a local IP address to this machine, did you mean --advertise-exit-node?`,
+			wantErr: `cannot use 100.105.106.107 as an exit node as it is a local IP address to this machine; did you mean --advertise-exit-node?`,
 		},
 		{
 			name: "warn_linux_netfilter_nodivert",
@@ -658,6 +661,39 @@ func TestPrefsFromUpArgs(t *testing.T) {
 				NoSNAT:        true,
 			},
 		},
+		{
+			name: "via_route_good",
+			goos: "linux",
+			args: upArgsT{
+				advertiseRoutes: "fd7a:115c:a1e0:b1a::bb:10.0.0.0/112",
+				netfilterMode:   "off",
+			},
+			want: &ipn.Prefs{
+				WantRunning: true,
+				NoSNAT:      true,
+				AdvertiseRoutes: []netip.Prefix{
+					netip.MustParsePrefix("fd7a:115c:a1e0:b1a::bb:10.0.0.0/112"),
+				},
+			},
+		},
+		{
+			name: "via_route_short_prefix",
+			goos: "linux",
+			args: upArgsT{
+				advertiseRoutes: "fd7a:115c:a1e0:b1a::/64",
+				netfilterMode:   "off",
+			},
+			wantErr: "fd7a:115c:a1e0:b1a::/64 4-in-6 prefix must be at least a /96",
+		},
+		{
+			name: "via_route_short_reserved_siteid",
+			goos: "linux",
+			args: upArgsT{
+				advertiseRoutes: "fd7a:115c:a1e0:b1a:1234:5678::/112",
+				netfilterMode:   "off",
+			},
+			wantErr: "route fd7a:115c:a1e0:b1a:1234:5678::/112 contains invalid site ID 12345678; must be 0xff or less",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -750,6 +786,10 @@ func TestUpdatePrefs(t *testing.T) {
 		curPrefs *ipn.Prefs
 		env      upCheckEnv // empty goos means "linux"
 
+		// checkUpdatePrefsMutations, if non-nil, is run with the new prefs after
+		// updatePrefs might've mutated them (from applyImplicitPrefs).
+		checkUpdatePrefsMutations func(t *testing.T, newPrefs *ipn.Prefs)
+
 		wantSimpleUp   bool
 		wantJustEditMP *ipn.MaskedPrefs
 		wantErrSubtr   string
@@ -851,6 +891,28 @@ func TestUpdatePrefs(t *testing.T) {
 			},
 			env: upCheckEnv{backendState: "Running"},
 		},
+		{
+			// Issue 3808: explicitly empty --operator= should clear value.
+			name:  "explicit_empty_operator",
+			flags: []string{"--operator="},
+			curPrefs: &ipn.Prefs{
+				ControlURL:       "https://login.tailscale.com",
+				CorpDNS:          true,
+				AllowSingleHosts: true,
+				NetfilterMode:    preftype.NetfilterOn,
+				OperatorUser:     "somebody",
+			},
+			env: upCheckEnv{user: "somebody", backendState: "Running"},
+			wantJustEditMP: &ipn.MaskedPrefs{
+				OperatorUserSet: true,
+				WantRunningSet:  true,
+			},
+			checkUpdatePrefsMutations: func(t *testing.T, prefs *ipn.Prefs) {
+				if prefs.OperatorUser != "" {
+					t.Errorf("operator sent to backend should be empty; got %q", prefs.OperatorUser)
+				}
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -858,7 +920,8 @@ func TestUpdatePrefs(t *testing.T) {
 				tt.env.goos = "linux"
 			}
 			tt.env.flagSet = newUpFlagSet(tt.env.goos, &tt.env.upArgs)
-			tt.env.flagSet.Parse(tt.flags)
+			flags := CleanUpArgs(tt.flags)
+			tt.env.flagSet.Parse(flags)
 
 			newPrefs, err := prefsFromUpArgs(tt.env.upArgs, t.Logf, new(ipnstate.Status), tt.env.goos)
 			if err != nil {
@@ -874,6 +937,9 @@ func TestUpdatePrefs(t *testing.T) {
 				}
 				t.Fatal(err)
 			}
+			if tt.checkUpdatePrefsMutations != nil {
+				tt.checkUpdatePrefsMutations(t, newPrefs)
+			}
 			if simpleUp != tt.wantSimpleUp {
 				t.Fatalf("simpleUp=%v, want %v", simpleUp, tt.wantSimpleUp)
 			}
@@ -890,136 +956,32 @@ func TestUpdatePrefs(t *testing.T) {
 	}
 }
 
-var cmpIP = cmp.Comparer(func(a, b netaddr.IP) bool {
+var cmpIP = cmp.Comparer(func(a, b netip.Addr) bool {
 	return a == b
 })
 
-func TestExitNodeIPOfArg(t *testing.T) {
-	mustIP := netaddr.MustParseIP
+func TestCleanUpArgs(t *testing.T) {
+	c := qt.New(t)
 	tests := []struct {
-		name    string
-		arg     string
-		st      *ipnstate.Status
-		want    netaddr.IP
-		wantErr string
+		in   []string
+		want []string
 	}{
-		{
-			name: "ip_while_stopped_okay",
-			arg:  "1.2.3.4",
-			st: &ipnstate.Status{
-				BackendState: "Stopped",
-			},
-			want: mustIP("1.2.3.4"),
-		},
-		{
-			name: "ip_not_found",
-			arg:  "1.2.3.4",
-			st: &ipnstate.Status{
-				BackendState: "Running",
-			},
-			wantErr: `no node found in netmap with IP 1.2.3.4`,
-		},
-		{
-			name: "ip_not_exit",
-			arg:  "1.2.3.4",
-			st: &ipnstate.Status{
-				BackendState: "Running",
-				Peer: map[key.NodePublic]*ipnstate.PeerStatus{
-					key.NewNode().Public(): {
-						TailscaleIPs: []netaddr.IP{mustIP("1.2.3.4")},
-					},
-				},
-			},
-			wantErr: `node 1.2.3.4 is not advertising an exit node`,
-		},
-		{
-			name: "ip",
-			arg:  "1.2.3.4",
-			st: &ipnstate.Status{
-				BackendState: "Running",
-				Peer: map[key.NodePublic]*ipnstate.PeerStatus{
-					key.NewNode().Public(): {
-						TailscaleIPs:   []netaddr.IP{mustIP("1.2.3.4")},
-						ExitNodeOption: true,
-					},
-				},
-			},
-			want: mustIP("1.2.3.4"),
-		},
-		{
-			name:    "no_match",
-			arg:     "unknown",
-			st:      &ipnstate.Status{MagicDNSSuffix: ".foo"},
-			wantErr: `invalid value "unknown" for --exit-node; must be IP or unique node name`,
-		},
-		{
-			name: "name",
-			arg:  "skippy",
-			st: &ipnstate.Status{
-				MagicDNSSuffix: ".foo",
-				Peer: map[key.NodePublic]*ipnstate.PeerStatus{
-					key.NewNode().Public(): {
-						DNSName:        "skippy.foo.",
-						TailscaleIPs:   []netaddr.IP{mustIP("1.0.0.2")},
-						ExitNodeOption: true,
-					},
-				},
-			},
-			want: mustIP("1.0.0.2"),
-		},
-		{
-			name: "name_not_exit",
-			arg:  "skippy",
-			st: &ipnstate.Status{
-				MagicDNSSuffix: ".foo",
-				Peer: map[key.NodePublic]*ipnstate.PeerStatus{
-					key.NewNode().Public(): {
-						DNSName:      "skippy.foo.",
-						TailscaleIPs: []netaddr.IP{mustIP("1.0.0.2")},
-					},
-				},
-			},
-			wantErr: `node "skippy" is not advertising an exit node`,
-		},
-		{
-			name: "ambiguous",
-			arg:  "skippy",
-			st: &ipnstate.Status{
-				MagicDNSSuffix: ".foo",
-				Peer: map[key.NodePublic]*ipnstate.PeerStatus{
-					key.NewNode().Public(): {
-						DNSName:        "skippy.foo.",
-						TailscaleIPs:   []netaddr.IP{mustIP("1.0.0.2")},
-						ExitNodeOption: true,
-					},
-					key.NewNode().Public(): {
-						DNSName:        "SKIPPY.foo.",
-						TailscaleIPs:   []netaddr.IP{mustIP("1.0.0.2")},
-						ExitNodeOption: true,
-					},
-				},
-			},
-			wantErr: `ambiguous exit node name "skippy"`,
-		},
+		{in: []string{"something"}, want: []string{"something"}},
+		{in: []string{}, want: []string{}},
+		{in: []string{"--authkey=0"}, want: []string{"--auth-key=0"}},
+		{in: []string{"a", "--authkey=1", "b"}, want: []string{"a", "--auth-key=1", "b"}},
+		{in: []string{"a", "--auth-key=2", "b"}, want: []string{"a", "--auth-key=2", "b"}},
+		{in: []string{"a", "-authkey=3", "b"}, want: []string{"a", "--auth-key=3", "b"}},
+		{in: []string{"a", "-auth-key=4", "b"}, want: []string{"a", "-auth-key=4", "b"}},
+		{in: []string{"a", "--authkey", "5", "b"}, want: []string{"a", "--auth-key", "5", "b"}},
+		{in: []string{"a", "-authkey", "6", "b"}, want: []string{"a", "--auth-key", "6", "b"}},
+		{in: []string{"a", "authkey", "7", "b"}, want: []string{"a", "authkey", "7", "b"}},
+		{in: []string{"--authkeyexpiry", "8"}, want: []string{"--authkeyexpiry", "8"}},
+		{in: []string{"--auth-key-expiry", "9"}, want: []string{"--auth-key-expiry", "9"}},
 	}
+
 	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, err := exitNodeIPOfArg(tt.arg, tt.st)
-			if err != nil {
-				if err.Error() == tt.wantErr {
-					return
-				}
-				if tt.wantErr == "" {
-					t.Fatal(err)
-				}
-				t.Fatalf("error = %#q; want %#q", err, tt.wantErr)
-			}
-			if tt.wantErr != "" {
-				t.Fatalf("got %v; want error %#q", got, tt.wantErr)
-			}
-			if got != tt.want {
-				t.Fatalf("got %v; want %v", got, tt.want)
-			}
-		})
+		got := CleanUpArgs(tt.in)
+		c.Assert(got, qt.DeepEquals, tt.want)
 	}
 }

cmd/tailscale/cli/configure-host.go

@@ -0,0 +1,85 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cli
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"runtime"
+	"strings"
+
+	"github.com/peterbourgon/ff/v3/ffcli"
+	"tailscale.com/hostinfo"
+	"tailscale.com/version/distro"
+)
+
+var configureHostCmd = &ffcli.Command{
+	Name:      "configure-host",
+	Exec:      runConfigureHost,
+	ShortHelp: "Configure Synology to enable more Tailscale features",
+	LongHelp: strings.TrimSpace(`
+The 'configure-host' command is intended to run at boot as root
+to create the /dev/net/tun device and give the tailscaled binary
+permission to use it.
+
+See: https://tailscale.com/kb/1152/synology-outbound/
+`),
+	FlagSet: (func() *flag.FlagSet {
+		fs := flag.NewFlagSet("configure-host", flag.ExitOnError)
+		return fs
+	})(),
+}
+
+var configureHostArgs struct{}
+
+func runConfigureHost(ctx context.Context, args []string) error {
+	if len(args) > 0 {
+		return errors.New("unknown arguments")
+	}
+	if runtime.GOOS != "linux" || distro.Get() != distro.Synology {
+		return errors.New("only implemented on Synology")
+	}
+	if uid := os.Getuid(); uid != 0 {
+		return fmt.Errorf("must be run as root, not %q (%v)", os.Getenv("USER"), uid)
+	}
+	osVer := hostinfo.GetOSVersion()
+	isDSM6 := strings.HasPrefix(osVer, "Synology 6")
+	isDSM7 := strings.HasPrefix(osVer, "Synology 7")
+	if !isDSM6 && !isDSM7 {
+		return fmt.Errorf("unsupported DSM version %q", osVer)
+	}
+	if _, err := os.Stat("/dev/net/tun"); os.IsNotExist(err) {
+		if err := os.MkdirAll("/dev/net", 0755); err != nil {
+			return fmt.Errorf("creating /dev/net: %v", err)
+		}
+		if out, err := exec.Command("/bin/mknod", "/dev/net/tun", "c", "10", "200").CombinedOutput(); err != nil {
+			return fmt.Errorf("creating /dev/net/tun: %v, %s", err, out)
+		}
+	}
+	if err := os.Chmod("/dev/net/tun", 0666); err != nil {
+		return err
+	}
+	if isDSM6 {
+		fmt.Printf("/dev/net/tun exists and has permissions 0666. Skipping setcap on DSM6.\n")
+		return nil
+	}
+
+	const daemonBin = "/var/packages/Tailscale/target/bin/tailscaled"
+	if _, err := os.Stat(daemonBin); err != nil {
+		if os.IsNotExist(err) {
+			return fmt.Errorf("tailscaled binary not found at %s. Is the Tailscale *.spk package installed?", daemonBin)
+		}
+		return err
+	}
+	if out, err := exec.Command("/bin/setcap", "cap_net_admin,cap_net_raw+eip", daemonBin).CombinedOutput(); err != nil {
+		return fmt.Errorf("setcap: %v, %s", err, out)
+	}
+	fmt.Printf("Done. To restart Tailscale to use the new permissions, run:\n\n  sudo synosystemctl restart pkgctl-Tailscale.service\n\n")
+	return nil
+}

cmd/tailscale/cli/debug.go

@@ -8,12 +8,16 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"flag"
 	"fmt"
 	"io"
 	"log"
+	"net"
+	"net/http"
+	"net/netip"
 	"os"
 	"runtime"
 	"strconv"
@@ -21,10 +25,14 @@ import (
 	"time"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"tailscale.com/client/tailscale"
+	"tailscale.com/control/controlhttp"
+	"tailscale.com/hostinfo"
 	"tailscale.com/ipn"
+	"tailscale.com/net/tsaddr"
 	"tailscale.com/paths"
 	"tailscale.com/safesocket"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/key"
 )
 
 var debugCmd = &ffcli.Command{
@@ -32,7 +40,7 @@ var debugCmd = &ffcli.Command{
 	Exec:     runDebug,
 	LongHelp: `"tailscale debug" contains misc debug facilities; it is not a stable interface.`,
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("debug")
+		fs := flag.NewFlagSet("debug", flag.ExitOnError)
 		fs.StringVar(&debugArgs.file, "file", "", "get, delete:NAME, or NAME")
 		fs.StringVar(&debugArgs.cpuFile, "cpu-profile", "", "if non-empty, grab a CPU profile for --profile-sec seconds and write it to this file; - for stdout")
 		fs.StringVar(&debugArgs.memFile, "mem-profile", "", "if non-empty, grab a memory profile and write it to this file; - for stdout")
@@ -55,7 +63,7 @@ var debugCmd = &ffcli.Command{
 			Exec:      runDaemonMetrics,
 			ShortHelp: "print tailscaled's metrics",
 			FlagSet: (func() *flag.FlagSet {
-				fs := newFlagSet("metrics")
+				fs := flag.NewFlagSet("metrics", flag.ExitOnError)
 				fs.BoolVar(&metricsArgs.watch, "watch", false, "print JSON dump of delta values")
 				return fs
 			})(),
@@ -65,6 +73,16 @@ var debugCmd = &ffcli.Command{
 			Exec:      runEnv,
 			ShortHelp: "print cmd/tailscale environment",
 		},
+		{
+			Name:      "stat",
+			Exec:      runStat,
+			ShortHelp: "stat a file",
+		},
+		{
+			Name:      "hostinfo",
+			Exec:      runHostinfo,
+			ShortHelp: "print hostinfo",
+		},
 		{
 			Name:      "local-creds",
 			Exec:      runLocalCreds,
@@ -85,7 +103,7 @@ var debugCmd = &ffcli.Command{
 			Exec:      runPrefs,
 			ShortHelp: "print prefs",
 			FlagSet: (func() *flag.FlagSet {
-				fs := newFlagSet("prefs")
+				fs := flag.NewFlagSet("prefs", flag.ExitOnError)
 				fs.BoolVar(&prefsArgs.pretty, "pretty", false, "If true, pretty-print output")
 				return fs
 			})(),
@@ -95,11 +113,27 @@ var debugCmd = &ffcli.Command{
 			Exec:      runWatchIPN,
 			ShortHelp: "subscribe to IPN message bus",
 			FlagSet: (func() *flag.FlagSet {
-				fs := newFlagSet("watch-ipn")
+				fs := flag.NewFlagSet("watch-ipn", flag.ExitOnError)
 				fs.BoolVar(&watchIPNArgs.netmap, "netmap", true, "include netmap in messages")
 				return fs
 			})(),
 		},
+		{
+			Name:      "via",
+			Exec:      runVia,
+			ShortHelp: "convert between site-specific IPv4 CIDRs and IPv6 'via' routes",
+		},
+		{
+			Name:      "ts2021",
+			Exec:      runTS2021,
+			ShortHelp: "debug ts2021 protocol connectivity",
+			FlagSet: (func() *flag.FlagSet {
+				fs := flag.NewFlagSet("ts2021", flag.ExitOnError)
+				fs.StringVar(&ts2021Args.host, "host", "controlplane.tailscale.com", "hostname of control plane")
+				fs.IntVar(&ts2021Args.version, "version", int(tailcfg.CurrentCapabilityVersion), "protocol version")
+				return fs
+			})(),
+		},
 	},
 }
 
@@ -112,7 +146,7 @@ var debugArgs struct {
 
 func writeProfile(dst string, v []byte) error {
 	if dst == "-" {
-		_, err := Stdout.Write(v)
+		_, err := os.Stdout.Write(v)
 		return err
 	}
 	return os.WriteFile(dst, v, 0600)
@@ -136,7 +170,7 @@ func runDebug(ctx context.Context, args []string) error {
 	if out := debugArgs.cpuFile; out != "" {
 		usedFlag = true // TODO(bradfitz): add "profile" subcommand
 		log.Printf("Capturing CPU profile for %v seconds ...", debugArgs.cpuSec)
-		if v, err := tailscale.Profile(ctx, "profile", debugArgs.cpuSec); err != nil {
+		if v, err := localClient.Profile(ctx, "profile", debugArgs.cpuSec); err != nil {
 			return err
 		} else {
 			if err := writeProfile(out, v); err != nil {
@@ -148,7 +182,7 @@ func runDebug(ctx context.Context, args []string) error {
 	if out := debugArgs.memFile; out != "" {
 		usedFlag = true // TODO(bradfitz): add "profile" subcommand
 		log.Printf("Capturing memory profile ...")
-		if v, err := tailscale.Profile(ctx, "heap", 0); err != nil {
+		if v, err := localClient.Profile(ctx, "heap", 0); err != nil {
 			return err
 		} else {
 			if err := writeProfile(out, v); err != nil {
@@ -160,25 +194,25 @@ func runDebug(ctx context.Context, args []string) error {
 	if debugArgs.file != "" {
 		usedFlag = true // TODO(bradfitz): add "file" subcommand
 		if debugArgs.file == "get" {
-			wfs, err := tailscale.WaitingFiles(ctx)
+			wfs, err := localClient.WaitingFiles(ctx)
 			if err != nil {
 				fatalf("%v\n", err)
 			}
-			e := json.NewEncoder(Stdout)
+			e := json.NewEncoder(os.Stdout)
 			e.SetIndent("", "\t")
 			e.Encode(wfs)
 			return nil
 		}
 		delete := strings.HasPrefix(debugArgs.file, "delete:")
 		if delete {
-			return tailscale.DeleteWaitingFile(ctx, strings.TrimPrefix(debugArgs.file, "delete:"))
+			return localClient.DeleteWaitingFile(ctx, strings.TrimPrefix(debugArgs.file, "delete:"))
 		}
-		rc, size, err := tailscale.GetWaitingFile(ctx, debugArgs.file)
+		rc, size, err := localClient.GetWaitingFile(ctx, debugArgs.file)
 		if err != nil {
 			return err
 		}
 		log.Printf("Size: %v\n", size)
-		io.Copy(Stdout, rc)
+		io.Copy(os.Stdout, rc)
 		return nil
 	}
 	if usedFlag {
@@ -192,14 +226,14 @@ func runDebug(ctx context.Context, args []string) error {
 func runLocalCreds(ctx context.Context, args []string) error {
 	port, token, err := safesocket.LocalTCPPortAndToken()
 	if err == nil {
-		printf("curl -u:%s http://localhost:%d/localapi/v0/status\n", token, port)
+		fmt.Printf("curl -u:%s http://localhost:%d/localapi/v0/status\n", token, port)
 		return nil
 	}
 	if runtime.GOOS == "windows" {
-		printf("curl http://localhost:%v/localapi/v0/status\n", safesocket.WindowsLocalPort)
+		fmt.Printf("curl http://localhost:%v/localapi/v0/status\n", safesocket.WindowsLocalPort)
 		return nil
 	}
-	printf("curl --unix-socket %s http://foo/localapi/v0/status\n", paths.DefaultTailscaledSocket())
+	fmt.Printf("curl --unix-socket %s http://foo/localapi/v0/status\n", paths.DefaultTailscaledSocket())
 	return nil
 }
 
@@ -208,15 +242,15 @@ var prefsArgs struct {
 }
 
 func runPrefs(ctx context.Context, args []string) error {
-	prefs, err := tailscale.GetPrefs(ctx)
+	prefs, err := localClient.GetPrefs(ctx)
 	if err != nil {
 		return err
 	}
 	if prefsArgs.pretty {
-		outln(prefs.Pretty())
+		fmt.Println(prefs.Pretty())
 	} else {
 		j, _ := json.MarshalIndent(prefs, "", "\t")
-		outln(string(j))
+		fmt.Println(string(j))
 	}
 	return nil
 }
@@ -234,7 +268,7 @@ func runWatchIPN(ctx context.Context, args []string) error {
 			n.NetMap = nil
 		}
 		j, _ := json.MarshalIndent(n, "", "\t")
-		printf("%s\n", j)
+		fmt.Printf("%s\n", j)
 	})
 	bc.RequestEngineStatus()
 	pump(ctx, bc, c)
@@ -242,13 +276,13 @@ func runWatchIPN(ctx context.Context, args []string) error {
 }
 
 func runDERPMap(ctx context.Context, args []string) error {
-	dm, err := tailscale.CurrentDERPMap(ctx)
+	dm, err := localClient.CurrentDERPMap(ctx)
 	if err != nil {
 		return fmt.Errorf(
 			"failed to get local derp map, instead `curl %s/derpmap/default`: %w", ipn.DefaultControlURL, err,
 		)
 	}
-	enc := json.NewEncoder(Stdout)
+	enc := json.NewEncoder(os.Stdout)
 	enc.SetIndent("", "\t")
 	enc.Encode(dm)
 	return nil
@@ -259,23 +293,52 @@ func localAPIAction(action string) func(context.Context, []string) error {
 		if len(args) > 0 {
 			return errors.New("unexpected arguments")
 		}
-		return tailscale.DebugAction(ctx, action)
+		return localClient.DebugAction(ctx, action)
 	}
 }
 
 func runEnv(ctx context.Context, args []string) error {
 	for _, e := range os.Environ() {
-		outln(e)
+		fmt.Println(e)
 	}
 	return nil
 }
 
+func runStat(ctx context.Context, args []string) error {
+	for _, a := range args {
+		fi, err := os.Lstat(a)
+		if err != nil {
+			fmt.Printf("%s: %v\n", a, err)
+			continue
+		}
+		fmt.Printf("%s: %v, %v\n", a, fi.Mode(), fi.Size())
+		if fi.IsDir() {
+			ents, _ := os.ReadDir(a)
+			for i, ent := range ents {
+				if i == 25 {
+					fmt.Printf("  ...\n")
+					break
+				}
+				fmt.Printf("  - %s\n", ent.Name())
+			}
+		}
+	}
+	return nil
+}
+
+func runHostinfo(ctx context.Context, args []string) error {
+	hi := hostinfo.New()
+	j, _ := json.MarshalIndent(hi, "", "  ")
+	os.Stdout.Write(j)
+	return nil
+}
+
 func runDaemonGoroutines(ctx context.Context, args []string) error {
-	goroutines, err := tailscale.Goroutines(ctx)
+	goroutines, err := localClient.Goroutines(ctx)
 	if err != nil {
 		return err
 	}
-	Stdout.Write(goroutines)
+	os.Stdout.Write(goroutines)
 	return nil
 }
 
@@ -286,12 +349,12 @@ var metricsArgs struct {
 func runDaemonMetrics(ctx context.Context, args []string) error {
 	last := map[string]int64{}
 	for {
-		out, err := tailscale.DaemonMetrics(ctx)
+		out, err := localClient.DaemonMetrics(ctx)
 		if err != nil {
 			return err
 		}
 		if !metricsArgs.watch {
-			Stdout.Write(out)
+			os.Stdout.Write(out)
 			return nil
 		}
 		bs := bufio.NewScanner(bytes.NewReader(out))
@@ -328,10 +391,117 @@ func runDaemonMetrics(ctx context.Context, args []string) error {
 		if len(changes) > 0 {
 			format := fmt.Sprintf("%%-%ds %%+5d => %%v\n", maxNameLen)
 			for _, c := range changes {
-				fmt.Fprintf(Stdout, format, c.name, c.to-c.from, c.to)
+				fmt.Fprintf(os.Stdout, format, c.name, c.to-c.from, c.to)
 			}
-			io.WriteString(Stdout, "\n")
+			io.WriteString(os.Stdout, "\n")
 		}
 		time.Sleep(time.Second)
 	}
 }
+
+func runVia(ctx context.Context, args []string) error {
+	switch len(args) {
+	default:
+		return errors.New("expect either <site-id> <v4-cidr> or <v6-route>")
+	case 1:
+		ipp, err := netip.ParsePrefix(args[0])
+		if err != nil {
+			return err
+		}
+		if !ipp.Addr().Is6() {
+			return errors.New("with one argument, expect an IPv6 CIDR")
+		}
+		if !tsaddr.TailscaleViaRange().Contains(ipp.Addr()) {
+			return errors.New("not a via route")
+		}
+		if ipp.Bits() < 96 {
+			return errors.New("short length, want /96 or more")
+		}
+		v4 := tsaddr.UnmapVia(ipp.Addr())
+		a := ipp.Addr().As16()
+		siteID := binary.BigEndian.Uint32(a[8:12])
+		fmt.Printf("site %v (0x%x), %v\n", siteID, siteID, netip.PrefixFrom(v4, ipp.Bits()-96))
+	case 2:
+		siteID, err := strconv.ParseUint(args[0], 0, 32)
+		if err != nil {
+			return fmt.Errorf("invalid site-id %q; must be decimal or hex with 0x prefix", args[0])
+		}
+		if siteID > 0xff {
+			return fmt.Errorf("site-id values over 255 are currently reserved")
+		}
+		ipp, err := netip.ParsePrefix(args[1])
+		if err != nil {
+			return err
+		}
+		via, err := tsaddr.MapVia(uint32(siteID), ipp)
+		if err != nil {
+			return err
+		}
+		fmt.Println(via)
+	}
+	return nil
+}
+
+var ts2021Args struct {
+	host    string // "controlplane.tailscale.com"
+	version int    // 27 or whatever
+}
+
+func runTS2021(ctx context.Context, args []string) error {
+	log.SetOutput(os.Stdout)
+	log.SetFlags(log.Ltime | log.Lmicroseconds)
+
+	machinePrivate := key.NewMachine()
+	var dialer net.Dialer
+
+	var keys struct {
+		PublicKey key.MachinePublic
+	}
+	keysURL := "https://" + ts2021Args.host + "/key?v=" + strconv.Itoa(ts2021Args.version)
+	log.Printf("Fetching keys from %s ...", keysURL)
+	req, err := http.NewRequestWithContext(ctx, "GET", keysURL, nil)
+	if err != nil {
+		return err
+	}
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		log.Printf("Do: %v", err)
+		return err
+	}
+	if res.StatusCode != 200 {
+		log.Printf("Status: %v", res.Status)
+		return errors.New(res.Status)
+	}
+	if err := json.NewDecoder(res.Body).Decode(&keys); err != nil {
+		log.Printf("JSON: %v", err)
+		return fmt.Errorf("decoding /keys JSON: %w", err)
+	}
+	res.Body.Close()
+
+	dialFunc := func(ctx context.Context, network, address string) (net.Conn, error) {
+		log.Printf("Dial(%q, %q) ...", network, address)
+		c, err := dialer.DialContext(ctx, network, address)
+		if err != nil {
+			log.Printf("Dial(%q, %q) = %v", network, address, err)
+		} else {
+			log.Printf("Dial(%q, %q) = %v / %v", network, address, c.LocalAddr(), c.RemoteAddr())
+		}
+		return c, err
+	}
+
+	conn, err := controlhttp.Dial(ctx, net.JoinHostPort(ts2021Args.host, "80"), machinePrivate, keys.PublicKey, uint16(ts2021Args.version), dialFunc)
+	log.Printf("controlhttp.Dial = %p, %v", conn, err)
+	if err != nil {
+		return err
+	}
+	log.Printf("did noise handshake")
+
+	gotPeer := conn.Peer()
+	if gotPeer != keys.PublicKey {
+		log.Printf("peer = %v, want %v", gotPeer, keys.PublicKey)
+		return errors.New("key mismatch")
+	}
+
+	log.Printf("final underlying conn: %v / %v", conn.LocalAddr(), conn.RemoteAddr())
+	return nil
+}

cmd/tailscale/cli/down.go

@@ -6,10 +6,11 @@ package cli
 
 import (
 	"context"
+	"flag"
 	"fmt"
+	"os"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"tailscale.com/client/tailscale"
 	"tailscale.com/ipn"
 )
 
@@ -18,7 +19,14 @@ var downCmd = &ffcli.Command{
 	ShortUsage: "down",
 	ShortHelp:  "Disconnect from Tailscale",
 
-	Exec: runDown,
+	Exec:    runDown,
+	FlagSet: newDownFlagSet(),
+}
+
+func newDownFlagSet() *flag.FlagSet {
+	downf := flag.NewFlagSet("down", flag.ExitOnError)
+	registerAcceptRiskFlag(downf)
+	return downf
 }
 
 func runDown(ctx context.Context, args []string) error {
@@ -26,15 +34,21 @@ func runDown(ctx context.Context, args []string) error {
 		return fmt.Errorf("too many non-flag arguments: %q", args)
 	}
 
-	st, err := tailscale.Status(ctx)
+	if isSSHOverTailscale() {
+		if err := presentRiskToUser(riskLoseSSH, `You are connected over Tailscale; this action will disable Tailscale and result in your session disconnecting.`); err != nil {
+			return err
+		}
+	}
+
+	st, err := localClient.Status(ctx)
 	if err != nil {
 		return fmt.Errorf("error fetching current status: %w", err)
 	}
 	if st.BackendState == "Stopped" {
-		fmt.Fprintf(Stderr, "Tailscale was already stopped.\n")
+		fmt.Fprintf(os.Stderr, "Tailscale was already stopped.\n")
 		return nil
 	}
-	_, err = tailscale.EditPrefs(ctx, &ipn.MaskedPrefs{
+	_, err = localClient.EditPrefs(ctx, &ipn.MaskedPrefs{
 		Prefs: ipn.Prefs{
 			WantRunning: false,
 		},

cmd/tailscale/cli/file.go

@@ -14,7 +14,9 @@ import (
 	"log"
 	"mime"
 	"net/http"
+	"net/netip"
 	"os"
+	"path"
 	"path/filepath"
 	"strings"
 	"time"
@@ -22,8 +24,6 @@ import (
 
 	"github.com/peterbourgon/ff/v3/ffcli"
 	"golang.org/x/time/rate"
-	"inet.af/netaddr"
-	"tailscale.com/client/tailscale"
 	"tailscale.com/client/tailscale/apitype"
 	"tailscale.com/envknob"
 	"tailscale.com/ipn"
@@ -54,7 +54,7 @@ var fileCpCmd = &ffcli.Command{
 	ShortHelp:  "Copy file(s) to a host",
 	Exec:       runCp,
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("cp")
+		fs := flag.NewFlagSet("cp", flag.ExitOnError)
 		fs.StringVar(&cpArgs.name, "name", "", "alternate filename to use, especially useful when <file> is \"-\" (stdin)")
 		fs.BoolVar(&cpArgs.verbose, "verbose", false, "verbose output")
 		fs.BoolVar(&cpArgs.targets, "targets", false, "list possible file cp targets")
@@ -85,7 +85,7 @@ func runCp(ctx context.Context, args []string) error {
 		hadBrackets = true
 		target = strings.TrimSuffix(strings.TrimPrefix(target, "["), "]")
 	}
-	if ip, err := netaddr.ParseIP(target); err == nil && ip.Is6() && !hadBrackets {
+	if ip, err := netip.ParseAddr(target); err == nil && ip.Is6() && !hadBrackets {
 		return fmt.Errorf("an IPv6 literal must be written as [%s]", ip)
 	} else if hadBrackets && (err != nil || !ip.Is6()) {
 		return errors.New("unexpected brackets around target")
@@ -100,7 +100,7 @@ func runCp(ctx context.Context, args []string) error {
 		return fmt.Errorf("can't send to %s: %v", target, err)
 	}
 	if isOffline {
-		fmt.Fprintf(Stderr, "# warning: %s is offline\n", target)
+		fmt.Fprintf(os.Stderr, "# warning: %s is offline\n", target)
 	}
 
 	if len(files) > 1 {
@@ -156,7 +156,7 @@ func runCp(ctx context.Context, args []string) error {
 		if cpArgs.verbose {
 			log.Printf("sending %q to %v/%v/%v ...", name, target, ip, stableID)
 		}
-		err := tailscale.PushFile(ctx, stableID, contentLength, name, fileContents)
+		err := localClient.PushFile(ctx, stableID, contentLength, name, fileContents)
 		if err != nil {
 			return err
 		}
@@ -168,18 +168,18 @@ func runCp(ctx context.Context, args []string) error {
 }
 
 func getTargetStableID(ctx context.Context, ipStr string) (id tailcfg.StableNodeID, isOffline bool, err error) {
-	ip, err := netaddr.ParseIP(ipStr)
+	ip, err := netip.ParseAddr(ipStr)
 	if err != nil {
 		return "", false, err
 	}
-	fts, err := tailscale.FileTargets(ctx)
+	fts, err := localClient.FileTargets(ctx)
 	if err != nil {
 		return "", false, err
 	}
 	for _, ft := range fts {
 		n := ft.Node
 		for _, a := range n.Addresses {
-			if a.IP() != ip {
+			if a.Addr() != ip {
 				continue
 			}
 			isOffline = n.Online != nil && !*n.Online
@@ -191,9 +191,9 @@ func getTargetStableID(ctx context.Context, ipStr string) (id tailcfg.StableNode
 
 // fileTargetErrorDetail returns a non-nil error saying why ip is an
 // invalid file sharing target.
-func fileTargetErrorDetail(ctx context.Context, ip netaddr.IP) error {
+func fileTargetErrorDetail(ctx context.Context, ip netip.Addr) error {
 	found := false
-	if st, err := tailscale.Status(ctx); err == nil && st.Self != nil {
+	if st, err := localClient.Status(ctx); err == nil && st.Self != nil {
 		for _, peer := range st.Peer {
 			for _, pip := range peer.TailscaleIPs {
 				if pip == ip {
@@ -260,7 +260,7 @@ func runCpTargets(ctx context.Context, args []string) error {
 	if len(args) > 0 {
 		return errors.New("invalid arguments with --targets")
 	}
-	fts, err := tailscale.FileTargets(ctx)
+	fts, err := localClient.FileTargets(ctx)
 	if err != nil {
 		return err
 	}
@@ -281,27 +281,176 @@ func runCpTargets(ctx context.Context, args []string) error {
 		if detail != "" {
 			detail = "\t" + detail
 		}
-		printf("%s\t%s%s\n", n.Addresses[0].IP(), n.ComputedName, detail)
+		fmt.Printf("%s\t%s%s\n", n.Addresses[0].Addr(), n.ComputedName, detail)
+	}
+	return nil
+}
+
+// onConflict is a flag.Value for the --conflict flag's three string options.
+type onConflict string
+
+const (
+	skipOnExist         onConflict = "skip"
+	overwriteExisting   onConflict = "overwrite" //  Overwrite any existing file at the target location
+	createNumberedFiles onConflict = "rename"    //  Create an alternately named file in the style of Chrome Downloads
+)
+
+func (v *onConflict) String() string { return string(*v) }
+
+func (v *onConflict) Set(s string) error {
+	if s == "" {
+		*v = skipOnExist
+		return nil
+	}
+	*v = onConflict(strings.ToLower(s))
+	if *v != skipOnExist && *v != overwriteExisting && *v != createNumberedFiles {
+		return fmt.Errorf("%q is not one of (skip|overwrite|rename)", s)
 	}
 	return nil
 }
 
 var fileGetCmd = &ffcli.Command{
 	Name:       "get",
-	ShortUsage: "file get [--wait] [--verbose] <target-directory>",
+	ShortUsage: "file get [--wait] [--verbose] [--conflict=(skip|overwrite|rename)] <target-directory>",
 	ShortHelp:  "Move files out of the Tailscale file inbox",
 	Exec:       runFileGet,
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("get")
+		fs := flag.NewFlagSet("get", flag.ExitOnError)
 		fs.BoolVar(&getArgs.wait, "wait", false, "wait for a file to arrive if inbox is empty")
+		fs.BoolVar(&getArgs.loop, "loop", false, "run get in a loop, receiving files as they come in")
 		fs.BoolVar(&getArgs.verbose, "verbose", false, "verbose output")
+		fs.Var(&getArgs.conflict, "conflict", `behavior when a conflicting (same-named) file already exists in the target directory.
+	skip:       skip conflicting files: leave them in the taildrop inbox and print an error. get any non-conflicting files
+	overwrite:  overwrite existing file
+	rename:     write to a new number-suffixed filename`)
 		return fs
 	})(),
 }
 
-var getArgs struct {
-	wait    bool
-	verbose bool
+var getArgs = struct {
+	wait     bool
+	loop     bool
+	verbose  bool
+	conflict onConflict
+}{conflict: skipOnExist}
+
+func numberedFileName(dir, name string, i int) string {
+	ext := path.Ext(name)
+	return filepath.Join(dir, fmt.Sprintf("%s (%d)%s",
+		strings.TrimSuffix(name, ext),
+		i, ext))
+}
+
+func openFileOrSubstitute(dir, base string, action onConflict) (*os.File, error) {
+	targetFile := filepath.Join(dir, base)
+	f, err := os.OpenFile(targetFile, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0644)
+	if err == nil {
+		return f, nil
+	}
+	// Something went wrong trying to open targetFile as a new file for writing.
+	switch action {
+	default:
+		// This should not happen.
+		return nil, fmt.Errorf("file issue. how to resolve this conflict? no one knows.")
+	case skipOnExist:
+		if _, statErr := os.Stat(targetFile); statErr == nil {
+			// we can stat a file at that path: so it already exists.
+			return nil, fmt.Errorf("refusing to overwrite file: %w", err)
+		}
+		return nil, fmt.Errorf("failed to write; %w", err)
+	case overwriteExisting:
+		// remove the target file and create it anew so we don't fall for an
+		// attacker who symlinks a known target name to a file he wants changed.
+		if err = os.Remove(targetFile); err != nil {
+			return nil, fmt.Errorf("unable to remove target file: %w", err)
+		}
+		if f, err = os.OpenFile(targetFile, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0644); err != nil {
+			return nil, fmt.Errorf("unable to overwrite: %w", err)
+		}
+		return f, nil
+	case createNumberedFiles:
+		// It's possible the target directory or filesystem isn't writable by us,
+		// not just that the target file(s) already exists.  For now, give up after
+		// a limited number of attempts.  In future, maybe distinguish this case
+		// and follow in the style of https://tinyurl.com/chromium100
+		maxAttempts := 100
+		for i := 1; i < maxAttempts; i++ {
+			if f, err = os.OpenFile(numberedFileName(dir, base, i), os.O_RDWR|os.O_CREATE|os.O_EXCL, 0644); err == nil {
+				return f, nil
+			}
+		}
+		return nil, fmt.Errorf("unable to find a name for writing %v, final attempt: %w", targetFile, err)
+	}
+}
+
+func receiveFile(ctx context.Context, wf apitype.WaitingFile, dir string) (targetFile string, size int64, err error) {
+	rc, size, err := localClient.GetWaitingFile(ctx, wf.Name)
+	if err != nil {
+		return "", 0, fmt.Errorf("opening inbox file %q: %w", wf.Name, err)
+	}
+	defer rc.Close()
+	f, err := openFileOrSubstitute(dir, wf.Name, getArgs.conflict)
+	if err != nil {
+		return "", 0, err
+	}
+	_, err = io.Copy(f, rc)
+	if err != nil {
+		f.Close()
+		return "", 0, fmt.Errorf("failed to write %v: %v", f.Name(), err)
+	}
+	return f.Name(), size, f.Close()
+}
+
+func runFileGetOneBatch(ctx context.Context, dir string) []error {
+	var wfs []apitype.WaitingFile
+	var err error
+	var errs []error
+	for len(errs) == 0 {
+		wfs, err = localClient.WaitingFiles(ctx)
+		if err != nil {
+			errs = append(errs, fmt.Errorf("getting WaitingFiles: %w", err))
+			break
+		}
+		if len(wfs) != 0 || !(getArgs.wait || getArgs.loop) {
+			break
+		}
+		if getArgs.verbose {
+			fmt.Printf("waiting for file...")
+		}
+		if err := waitForFile(ctx); err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	deleted := 0
+	for i, wf := range wfs {
+		if len(errs) > 100 {
+			// Likely, everything is broken.
+			// Don't try to receive any more files in this batch.
+			errs = append(errs, fmt.Errorf("too many errors in runFileGetOneBatch(). %d files unexamined", len(wfs)-i))
+			break
+		}
+		writtenFile, size, err := receiveFile(ctx, wf, dir)
+		if err != nil {
+			errs = append(errs, err)
+			continue
+		}
+		if getArgs.verbose {
+			fmt.Printf("wrote %v as %v (%d bytes)\n", wf.Name, writtenFile, size)
+		}
+		if err = localClient.DeleteWaitingFile(ctx, wf.Name); err != nil {
+			errs = append(errs, fmt.Errorf("deleting %q from inbox: %v", wf.Name, err))
+			continue
+		}
+		deleted++
+	}
+	if deleted == 0 && len(wfs) > 0 {
+		// persistently stuck files are basically an error
+		errs = append(errs, fmt.Errorf("moved %d/%d files", deleted, len(wfs)))
+	} else if getArgs.verbose {
+		fmt.Printf("moved %d/%d files\n", deleted, len(wfs))
+	}
+	return errs
 }
 
 func runFileGet(ctx context.Context, args []string) error {
@@ -318,66 +467,42 @@ func runFileGet(ctx context.Context, args []string) error {
 	if fi, err := os.Stat(dir); err != nil || !fi.IsDir() {
 		return fmt.Errorf("%q is not a directory", dir)
 	}
-
-	var wfs []apitype.WaitingFile
-	var err error
-	for {
-		wfs, err = tailscale.WaitingFiles(ctx)
-		if err != nil {
-			return fmt.Errorf("getting WaitingFiles: %w", err)
-		}
-		if len(wfs) != 0 || !getArgs.wait {
-			break
-		}
-		if getArgs.verbose {
-			log.Printf("waiting for file...")
-		}
-		if err := waitForFile(ctx); err != nil {
-			return err
-		}
-	}
-
-	deleted := 0
-	for _, wf := range wfs {
-		rc, size, err := tailscale.GetWaitingFile(ctx, wf.Name)
-		if err != nil {
-			return fmt.Errorf("opening inbox file %q: %v", wf.Name, err)
-		}
-		targetFile := filepath.Join(dir, wf.Name)
-		of, err := os.OpenFile(targetFile, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0644)
-		if err != nil {
-			if _, err := os.Stat(targetFile); err == nil {
-				return fmt.Errorf("refusing to overwrite %v", targetFile)
+	if getArgs.loop {
+		for {
+			errs := runFileGetOneBatch(ctx, dir)
+			for _, err := range errs {
+				fmt.Println(err)
+			}
+			if len(errs) > 0 {
+				// It's possible whatever caused the error(s) (e.g. conflicting target file,
+				// full disk, unwritable target directory) will re-occur if we try again so
+				// let's back off and not busy loop on error.
+				//
+				// If we've been invoked as:
+				//    tailscale file get --conflict=skip ~/Downloads
+				// then any file coming in named the same as one in ~/Downloads will always
+				// appear as an "error" until the user clears it, but other incoming files
+				// should be receivable when they arrive, so let's not wait too long to
+				// check again.
+				time.Sleep(5 * time.Second)
 			}
-			return err
 		}
-		_, err = io.Copy(of, rc)
-		rc.Close()
-		if err != nil {
-			return fmt.Errorf("failed to write %v: %v", targetFile, err)
-		}
-		if err := of.Close(); err != nil {
-			return err
-		}
-		if getArgs.verbose {
-			log.Printf("wrote %v (%d bytes)", wf.Name, size)
-		}
-		if err := tailscale.DeleteWaitingFile(ctx, wf.Name); err != nil {
-			return fmt.Errorf("deleting %q from inbox: %v", wf.Name, err)
-		}
-		deleted++
 	}
-	if getArgs.verbose {
-		log.Printf("moved %d files", deleted)
+	errs := runFileGetOneBatch(ctx, dir)
+	if len(errs) == 0 {
+		return nil
 	}
-	return nil
+	for _, err := range errs[:len(errs)-1] {
+		fmt.Println(err)
+	}
+	return errs[len(errs)-1]
 }
 
 func wipeInbox(ctx context.Context) error {
 	if getArgs.wait {
 		return errors.New("can't use --wait with /dev/null target")
 	}
-	wfs, err := tailscale.WaitingFiles(ctx)
+	wfs, err := localClient.WaitingFiles(ctx)
 	if err != nil {
 		return fmt.Errorf("getting WaitingFiles: %w", err)
 	}
@@ -386,7 +511,7 @@ func wipeInbox(ctx context.Context) error {
 		if getArgs.verbose {
 			log.Printf("deleting %v ...", wf.Name)
 		}
-		if err := tailscale.DeleteWaitingFile(ctx, wf.Name); err != nil {
+		if err := localClient.DeleteWaitingFile(ctx, wf.Name); err != nil {
 			return fmt.Errorf("deleting %q: %v", wf.Name, err)
 		}
 		deleted++
@@ -401,9 +526,10 @@ func waitForFile(ctx context.Context) error {
 	c, bc, pumpCtx, cancel := connect(ctx)
 	defer cancel()
 	fileWaiting := make(chan bool, 1)
+	notifyError := make(chan error, 1)
 	bc.SetNotifyCallback(func(n ipn.Notify) {
 		if n.ErrMessage != nil {
-			fatalf("Notify.ErrMessage: %v\n", *n.ErrMessage)
+			notifyError <- fmt.Errorf("Notify.ErrMessage: %v", *n.ErrMessage)
 		}
 		if n.FilesWaiting != nil {
 			select {
@@ -420,5 +546,7 @@ func waitForFile(ctx context.Context) error {
 		return pumpCtx.Err()
 	case <-ctx.Done():
 		return ctx.Err()
+	case err := <-notifyError:
+		return err
 	}
 }

cmd/tailscale/cli/id-token.go

@@ -0,0 +1,34 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cli
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/peterbourgon/ff/v3/ffcli"
+)
+
+var idTokenCmd = &ffcli.Command{
+	Name:       "id-token",
+	ShortUsage: "id-token <aud>",
+	ShortHelp:  "fetch an OIDC id-token for the Tailscale machine",
+	Exec:       runIDToken,
+}
+
+func runIDToken(ctx context.Context, args []string) error {
+	if len(args) != 1 {
+		return errors.New("usage: id-token <aud>")
+	}
+
+	tr, err := localClient.IDToken(ctx, args[0])
+	if err != nil {
+		return err
+	}
+
+	fmt.Println(tr.IDToken)
+	return nil
+}

cmd/tailscale/cli/ip.go

@@ -9,10 +9,9 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"net/netip"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"inet.af/netaddr"
-	"tailscale.com/client/tailscale"
 	"tailscale.com/ipn/ipnstate"
 )
 
@@ -23,7 +22,7 @@ var ipCmd = &ffcli.Command{
 	LongHelp:   "Show Tailscale IP addresses for peer. Peer defaults to the current machine.",
 	Exec:       runIP,
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("ip")
+		fs := flag.NewFlagSet("ip", flag.ExitOnError)
 		fs.BoolVar(&ipArgs.want1, "1", false, "only print one IP address")
 		fs.BoolVar(&ipArgs.want4, "4", false, "only print IPv4 address")
 		fs.BoolVar(&ipArgs.want6, "6", false, "only print IPv6 address")
@@ -59,7 +58,7 @@ func runIP(ctx context.Context, args []string) error {
 	if !v4 && !v6 {
 		v4, v6 = true, true
 	}
-	st, err := tailscale.Status(ctx)
+	st, err := localClient.Status(ctx)
 	if err != nil {
 		return err
 	}
@@ -86,7 +85,7 @@ func runIP(ctx context.Context, args []string) error {
 	for _, ip := range ips {
 		if ip.Is4() && v4 || ip.Is6() && v6 {
 			match = true
-			outln(ip)
+			fmt.Println(ip)
 		}
 	}
 	if !match {
@@ -101,7 +100,7 @@ func runIP(ctx context.Context, args []string) error {
 }
 
 func peerMatchingIP(st *ipnstate.Status, ipStr string) (ps *ipnstate.PeerStatus, ok bool) {
-	ip, err := netaddr.ParseIP(ipStr)
+	ip, err := netip.ParseAddr(ipStr)
 	if err != nil {
 		return
 	}

cmd/tailscale/cli/logout.go

@@ -10,7 +10,6 @@ import (
 	"strings"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"tailscale.com/client/tailscale"
 )
 
 var logoutCmd = &ffcli.Command{
@@ -30,5 +29,5 @@ func runLogout(ctx context.Context, args []string) error {
 	if len(args) > 0 {
 		return fmt.Errorf("too many non-flag arguments: %q", args)
 	}
-	return tailscale.Logout(ctx)
+	return localClient.Logout(ctx)
 }

cmd/tailscale/cli/nc.go

@@ -0,0 +1,62 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cli
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+
+	"github.com/peterbourgon/ff/v3/ffcli"
+)
+
+var ncCmd = &ffcli.Command{
+	Name:       "nc",
+	ShortUsage: "nc <hostname-or-IP> <port>",
+	ShortHelp:  "Connect to a port on a host, connected to stdin/stdout",
+	Exec:       runNC,
+}
+
+func runNC(ctx context.Context, args []string) error {
+	st, err := localClient.Status(ctx)
+	if err != nil {
+		return fixTailscaledConnectError(err)
+	}
+	description, ok := isRunningOrStarting(st)
+	if !ok {
+		fmt.Printf("%s\n", description)
+		os.Exit(1)
+	}
+
+	if len(args) != 2 {
+		return errors.New("usage: nc <hostname-or-IP> <port>")
+	}
+
+	hostOrIP, portStr := args[0], args[1]
+	port, err := strconv.ParseUint(portStr, 10, 16)
+	if err != nil {
+		return fmt.Errorf("invalid port number %q", portStr)
+	}
+
+	// TODO(bradfitz): also add UDP too, via flag?
+	c, err := localClient.DialTCP(ctx, hostOrIP, uint16(port))
+	if err != nil {
+		return fmt.Errorf("Dial(%q, %v): %w", hostOrIP, port, err)
+	}
+	defer c.Close()
+	errc := make(chan error, 1)
+	go func() {
+		_, err := io.Copy(os.Stdout, c)
+		errc <- err
+	}()
+	go func() {
+		_, err := io.Copy(c, os.Stdin)
+		errc <- err
+	}()
+	return <-errc
+}

cmd/tailscale/cli/netcheck.go

@@ -13,12 +13,12 @@ import (
 	"io/ioutil"
 	"log"
 	"net/http"
+	"os"
 	"sort"
 	"strings"
 	"time"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"tailscale.com/client/tailscale"
 	"tailscale.com/envknob"
 	"tailscale.com/ipn"
 	"tailscale.com/net/netcheck"
@@ -33,7 +33,7 @@ var netcheckCmd = &ffcli.Command{
 	ShortHelp:  "Print an analysis of local network conditions",
 	Exec:       runNetcheck,
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("netcheck")
+		fs := flag.NewFlagSet("netcheck", flag.ExitOnError)
 		fs.StringVar(&netcheckArgs.format, "format", "", `output format; empty (for human-readable), "json" or "json-line"`)
 		fs.DurationVar(&netcheckArgs.every, "every", 0, "if non-zero, do an incremental report with the given frequency")
 		fs.BoolVar(&netcheckArgs.verbose, "verbose", false, "verbose logs")
@@ -60,10 +60,10 @@ func runNetcheck(ctx context.Context, args []string) error {
 	}
 
 	if strings.HasPrefix(netcheckArgs.format, "json") {
-		fmt.Fprintln(Stderr, "# Warning: this JSON format is not yet considered a stable interface")
+		fmt.Fprintln(os.Stderr, "# Warning: this JSON format is not yet considered a stable interface")
 	}
 
-	dm, err := tailscale.CurrentDERPMap(ctx)
+	dm, err := localClient.CurrentDERPMap(ctx)
 	noRegions := dm != nil && len(dm.Regions) == 0
 	if noRegions {
 		log.Printf("No DERP map from tailscaled; using default.")
@@ -112,36 +112,38 @@ func printReport(dm *tailcfg.DERPMap, report *netcheck.Report) error {
 	}
 	if j != nil {
 		j = append(j, '\n')
-		Stdout.Write(j)
+		os.Stdout.Write(j)
 		return nil
 	}
 
-	printf("\nReport:\n")
-	printf("\t* UDP: %v\n", report.UDP)
+	fmt.Printf("\nReport:\n")
+	fmt.Printf("\t* UDP: %v\n", report.UDP)
 	if report.GlobalV4 != "" {
-		printf("\t* IPv4: yes, %v\n", report.GlobalV4)
+		fmt.Printf("\t* IPv4: yes, %v\n", report.GlobalV4)
 	} else {
-		printf("\t* IPv4: (no addr found)\n")
+		fmt.Printf("\t* IPv4: (no addr found)\n")
 	}
 	if report.GlobalV6 != "" {
-		printf("\t* IPv6: yes, %v\n", report.GlobalV6)
+		fmt.Printf("\t* IPv6: yes, %v\n", report.GlobalV6)
 	} else if report.IPv6 {
-		printf("\t* IPv6: (no addr found)\n")
+		fmt.Printf("\t* IPv6: (no addr found)\n")
+	} else if report.OSHasIPv6 {
+		fmt.Printf("\t* IPv6: no, but OS has support\n")
 	} else {
-		printf("\t* IPv6: no\n")
+		fmt.Printf("\t* IPv6: no, unavailable in OS\n")
 	}
-	printf("\t* MappingVariesByDestIP: %v\n", report.MappingVariesByDestIP)
-	printf("\t* HairPinning: %v\n", report.HairPinning)
-	printf("\t* PortMapping: %v\n", portMapping(report))
+	fmt.Printf("\t* MappingVariesByDestIP: %v\n", report.MappingVariesByDestIP)
+	fmt.Printf("\t* HairPinning: %v\n", report.HairPinning)
+	fmt.Printf("\t* PortMapping: %v\n", portMapping(report))
 
 	// When DERP latency checking failed,
 	// magicsock will try to pick the DERP server that
 	// most of your other nodes are also using
 	if len(report.RegionLatency) == 0 {
-		printf("\t* Nearest DERP: unknown (no response to latency probes)\n")
+		fmt.Printf("\t* Nearest DERP: unknown (no response to latency probes)\n")
 	} else {
-		printf("\t* Nearest DERP: %v\n", dm.Regions[report.PreferredDERP].RegionName)
-		printf("\t* DERP latency:\n")
+		fmt.Printf("\t* Nearest DERP: %v\n", dm.Regions[report.PreferredDERP].RegionName)
+		fmt.Printf("\t* DERP latency:\n")
 		var rids []int
 		for rid := range dm.Regions {
 			rids = append(rids, rid)
@@ -168,7 +170,7 @@ func printReport(dm *tailcfg.DERPMap, report *netcheck.Report) error {
 			if netcheckArgs.verbose {
 				derpNum = fmt.Sprintf("derp%d, ", rid)
 			}
-			printf("\t\t- %3s: %-7s (%s%s)\n", r.RegionCode, latency, derpNum, r.RegionName)
+			fmt.Printf("\t\t- %3s: %-7s (%s%s)\n", r.RegionCode, latency, derpNum, r.RegionName)
 		}
 	}
 	return nil

cmd/tailscale/cli/ping.go

@@ -11,14 +11,14 @@ import (
 	"fmt"
 	"log"
 	"net"
+	"net/netip"
 	"os"
 	"strings"
 	"time"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"tailscale.com/client/tailscale"
-	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/tailcfg"
 )
 
 var pingCmd = &ffcli.Command{
@@ -27,7 +27,7 @@ var pingCmd = &ffcli.Command{
 	ShortHelp:  "Ping a host at the Tailscale layer, see how it routed",
 	LongHelp: strings.TrimSpace(`
 
-The 'tailscale ping' command pings a peer node at the Tailscale layer
+The 'tailscale ping' command pings a peer node from the Tailscale layer
 and reports which route it took for each response. The first ping or
 so will likely go over DERP (Tailscale's TCP relay protocol) while NAT
 traversal finds a direct path through.
@@ -46,10 +46,12 @@ relay node.
 `),
 	Exec: runPing,
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("ping")
+		fs := flag.NewFlagSet("ping", flag.ExitOnError)
 		fs.BoolVar(&pingArgs.verbose, "verbose", false, "verbose output")
 		fs.BoolVar(&pingArgs.untilDirect, "until-direct", true, "stop once a direct path is established")
-		fs.BoolVar(&pingArgs.tsmp, "tsmp", false, "do a TSMP-level ping (through IP + wireguard, but not involving host OS stack)")
+		fs.BoolVar(&pingArgs.tsmp, "tsmp", false, "do a TSMP-level ping (through WireGuard, but not either host OS stack)")
+		fs.BoolVar(&pingArgs.icmp, "icmp", false, "do a ICMP-level ping (through WireGuard, but not the local host OS stack)")
+		fs.BoolVar(&pingArgs.peerAPI, "peerapi", false, "try hitting the peer's peerapi HTTP server")
 		fs.IntVar(&pingArgs.num, "c", 10, "max number of pings to send")
 		fs.DurationVar(&pingArgs.timeout, "timeout", 5*time.Second, "timeout before giving up on a ping")
 		return fs
@@ -61,38 +63,39 @@ var pingArgs struct {
 	untilDirect bool
 	verbose     bool
 	tsmp        bool
+	icmp        bool
+	peerAPI     bool
 	timeout     time.Duration
 }
 
+func pingType() tailcfg.PingType {
+	if pingArgs.tsmp {
+		return tailcfg.PingTSMP
+	}
+	if pingArgs.icmp {
+		return tailcfg.PingICMP
+	}
+	if pingArgs.peerAPI {
+		return tailcfg.PingPeerAPI
+	}
+	return tailcfg.PingDisco
+}
+
 func runPing(ctx context.Context, args []string) error {
-	st, err := tailscale.Status(ctx)
+	st, err := localClient.Status(ctx)
 	if err != nil {
 		return fixTailscaledConnectError(err)
 	}
 	description, ok := isRunningOrStarting(st)
 	if !ok {
-		printf("%s\n", description)
+		fmt.Printf("%s\n", description)
 		os.Exit(1)
 	}
 
-	c, bc, ctx, cancel := connect(ctx)
-	defer cancel()
-
 	if len(args) != 1 || args[0] == "" {
 		return errors.New("usage: ping <hostname-or-IP>")
 	}
 	var ip string
-	prc := make(chan *ipnstate.PingResult, 1)
-	bc.SetNotifyCallback(func(n ipn.Notify) {
-		if n.ErrMessage != nil {
-			fatalf("Notify.ErrMessage: %v", *n.ErrMessage)
-		}
-		if pr := n.PingResult; pr != nil && pr.IP == ip {
-			prc <- pr
-		}
-	})
-	pumpErr := make(chan error, 1)
-	go func() { pumpErr <- pump(ctx, bc, c) }()
 
 	hostOrIP := args[0]
 	ip, self, err := tailscaleIPFromArg(ctx, hostOrIP)
@@ -100,7 +103,7 @@ func runPing(ctx context.Context, args []string) error {
 		return err
 	}
 	if self {
-		printf("%v is local Tailscale IP\n", ip)
+		fmt.Printf("%v is local Tailscale IP\n", ip)
 		return nil
 	}
 
@@ -112,48 +115,57 @@ func runPing(ctx context.Context, args []string) error {
 	anyPong := false
 	for {
 		n++
-		bc.Ping(ip, pingArgs.tsmp)
-		timer := time.NewTimer(pingArgs.timeout)
-		select {
-		case <-timer.C:
-			printf("timeout waiting for ping reply\n")
-		case err := <-pumpErr:
-			return err
-		case pr := <-prc:
-			timer.Stop()
-			if pr.Err != "" {
-				if pr.IsLocalIP {
-					outln(pr.Err)
+		ctx, cancel := context.WithTimeout(ctx, pingArgs.timeout)
+		pr, err := localClient.Ping(ctx, netip.MustParseAddr(ip), pingType())
+		cancel()
+		if err != nil {
+			if errors.Is(err, context.DeadlineExceeded) {
+				fmt.Printf("ping %q timed out\n", ip)
+				if n == pingArgs.num {
+					if !anyPong {
+						return errors.New("no reply")
+					}
 					return nil
 				}
-				return errors.New(pr.Err)
+				continue
 			}
-			latency := time.Duration(pr.LatencySeconds * float64(time.Second)).Round(time.Millisecond)
-			via := pr.Endpoint
-			if pr.DERPRegionID != 0 {
-				via = fmt.Sprintf("DERP(%s)", pr.DERPRegionCode)
-			}
-			if pingArgs.tsmp {
-				// TODO(bradfitz): populate the rest of ipnstate.PingResult for TSMP queries?
-				// For now just say it came via TSMP.
-				via = "TSMP"
-			}
-			anyPong = true
-			extra := ""
-			if pr.PeerAPIPort != 0 {
-				extra = fmt.Sprintf(", %d", pr.PeerAPIPort)
-			}
-			printf("pong from %s (%s%s) via %v in %v\n", pr.NodeName, pr.NodeIP, extra, via, latency)
-			if pingArgs.tsmp {
-				return nil
-			}
-			if pr.Endpoint != "" && pingArgs.untilDirect {
-				return nil
-			}
-			time.Sleep(time.Second)
-		case <-ctx.Done():
-			return ctx.Err()
+			return err
 		}
+		if pr.Err != "" {
+			if pr.IsLocalIP {
+				fmt.Println(pr.Err)
+				return nil
+			}
+			return errors.New(pr.Err)
+		}
+		latency := time.Duration(pr.LatencySeconds * float64(time.Second)).Round(time.Millisecond)
+		via := pr.Endpoint
+		if pr.DERPRegionID != 0 {
+			via = fmt.Sprintf("DERP(%s)", pr.DERPRegionCode)
+		}
+		if via == "" {
+			// TODO(bradfitz): populate the rest of ipnstate.PingResult for TSMP queries?
+			// For now just say which protocol it used.
+			via = string(pingType())
+		}
+		if pingArgs.peerAPI {
+			fmt.Printf("hit peerapi of %s (%s) at %s in %s\n", pr.NodeIP, pr.NodeName, pr.PeerAPIURL, latency)
+			return nil
+		}
+		anyPong = true
+		extra := ""
+		if pr.PeerAPIPort != 0 {
+			extra = fmt.Sprintf(", %d", pr.PeerAPIPort)
+		}
+		fmt.Printf("pong from %s (%s%s) via %v in %v\n", pr.NodeName, pr.NodeIP, extra, via, latency)
+		if pingArgs.tsmp || pingArgs.icmp {
+			return nil
+		}
+		if pr.Endpoint != "" && pingArgs.untilDirect {
+			return nil
+		}
+		time.Sleep(time.Second)
+
 		if n == pingArgs.num {
 			if !anyPong {
 				return errors.New("no reply")
@@ -173,7 +185,7 @@ func tailscaleIPFromArg(ctx context.Context, hostOrIP string) (ip string, self b
 	}
 
 	// Otherwise, try to resolve it first from the network peer list.
-	st, err := tailscale.Status(ctx)
+	st, err := localClient.Status(ctx)
 	if err != nil {
 		return "", false, err
 	}

cmd/tailscale/cli/risks.go

@@ -0,0 +1,78 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cli
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"os/signal"
+	"strings"
+	"syscall"
+	"time"
+)
+
+var (
+	riskTypes     []string
+	acceptedRisks string
+	riskLoseSSH   = registerRiskType("lose-ssh")
+)
+
+func registerRiskType(riskType string) string {
+	riskTypes = append(riskTypes, riskType)
+	return riskType
+}
+
+// registerAcceptRiskFlag registers the --accept-risk flag. Accepted risks are accounted for
+// in presentRiskToUser.
+func registerAcceptRiskFlag(f *flag.FlagSet) {
+	f.StringVar(&acceptedRisks, "accept-risk", "", "accept risk and skip confirmation for risk types: "+strings.Join(riskTypes, ","))
+}
+
+// riskAccepted reports whether riskType is in acceptedRisks.
+func riskAccepted(riskType string) bool {
+	for _, r := range strings.Split(acceptedRisks, ",") {
+		if r == riskType {
+			return true
+		}
+	}
+	return false
+}
+
+var errAborted = errors.New("aborted, no changes made")
+
+// riskAbortTimeSeconds is the number of seconds to wait after displaying the
+// risk message before continuing with the operation.
+// It is used by the presentRiskToUser function below.
+const riskAbortTimeSeconds = 5
+
+// presentRiskToUser displays the risk message and waits for the user to
+// cancel. It returns errorAborted if the user aborts.
+func presentRiskToUser(riskType, riskMessage string) error {
+	if riskAccepted(riskType) {
+		return nil
+	}
+	fmt.Println(riskMessage)
+	fmt.Printf("To skip this warning, use --accept-risk=%s\n", riskType)
+
+	interrupt := make(chan os.Signal, 1)
+	signal.Notify(interrupt, syscall.SIGINT)
+	var msgLen int
+	for left := riskAbortTimeSeconds; left > 0; left-- {
+		msg := fmt.Sprintf("\rContinuing in %d seconds...", left)
+		msgLen = len(msg)
+		fmt.Print(msg)
+		select {
+		case <-interrupt:
+			fmt.Printf("\r%s\r", strings.Repeat(" ", msgLen+1))
+			return errAborted
+		case <-time.After(time.Second):
+			continue
+		}
+	}
+	fmt.Printf("\r%s\r", strings.Repeat(" ", msgLen))
+	return errAborted
+}

cmd/tailscale/cli/ssh.go

@@ -0,0 +1,210 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cli
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"net/netip"
+	"os"
+	"os/user"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"github.com/peterbourgon/ff/v3/ffcli"
+	"tailscale.com/envknob"
+	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/net/tsaddr"
+	"tailscale.com/version"
+)
+
+var sshCmd = &ffcli.Command{
+	Name:       "ssh",
+	ShortUsage: "ssh [user@]<host> [args...]",
+	ShortHelp:  "SSH to a Tailscale machine",
+	Exec:       runSSH,
+}
+
+func runSSH(ctx context.Context, args []string) error {
+	if runtime.GOOS == "darwin" && version.IsSandboxedMacOS() && !envknob.UseWIPCode() {
+		return errors.New("The 'tailscale ssh' subcommand is not available on sandboxed macOS builds.\nUse the regular 'ssh' client instead.")
+	}
+	if len(args) == 0 {
+		return errors.New("usage: ssh [user@]<host>")
+	}
+	arg, argRest := args[0], args[1:]
+	username, host, ok := strings.Cut(arg, "@")
+	if !ok {
+		host = arg
+		lu, err := user.Current()
+		if err != nil {
+			return nil
+		}
+		username = lu.Username
+	}
+
+	st, err := localClient.Status(ctx)
+	if err != nil {
+		return err
+	}
+
+	// hostForSSH is the hostname we'll tell OpenSSH we're
+	// connecting to, so we have to maintain fewer entries in the
+	// known_hosts files.
+	hostForSSH := host
+	if v, ok := nodeDNSNameFromArg(st, host); ok {
+		hostForSSH = v
+	}
+
+	ssh, err := findSSH()
+	if err != nil {
+		// TODO(bradfitz): use Go's crypto/ssh client instead
+		// of failing. But for now:
+		return fmt.Errorf("no system 'ssh' command found: %w", err)
+	}
+	tailscaleBin, err := os.Executable()
+	if err != nil {
+		return err
+	}
+	knownHostsFile, err := writeKnownHosts(st)
+	if err != nil {
+		return err
+	}
+
+	argv := []string{ssh}
+
+	if envknob.Bool("TS_DEBUG_SSH_EXEC") {
+		argv = append(argv, "-vvv")
+	}
+	argv = append(argv,
+		// Only trust SSH hosts that we know about.
+		"-o", fmt.Sprintf("UserKnownHostsFile %q", knownHostsFile),
+		"-o", "UpdateHostKeys no",
+		"-o", "StrictHostKeyChecking yes",
+	)
+
+	// TODO(bradfitz): nc is currently broken on macOS:
+	// https://github.com/tailscale/tailscale/issues/4529
+	// So don't use it for now. MagicDNS is usually working on macOS anyway
+	// and they're not in userspace mode, so 'nc' isn't very useful.
+	if runtime.GOOS != "darwin" {
+		argv = append(argv,
+			"-o", fmt.Sprintf("ProxyCommand %q --socket=%q nc %%h %%p",
+				tailscaleBin,
+				rootArgs.socket,
+			))
+	}
+
+	// Explicitly rebuild the user@host argument rather than
+	// passing it through.  In general, the use of OpenSSH's ssh
+	// binary is a crutch for now.  We don't want to be
+	// Hyrum-locked into passing through all OpenSSH flags to the
+	// OpenSSH client forever. We try to make our flags and args
+	// be compatible, but only a subset. The "tailscale ssh"
+	// command should be a simple and portable one. If they want
+	// to use a different one, we'll later be making stock ssh
+	// work well by default too. (doing things like automatically
+	// setting known_hosts, etc)
+	argv = append(argv, username+"@"+hostForSSH)
+
+	argv = append(argv, argRest...)
+
+	if envknob.Bool("TS_DEBUG_SSH_EXEC") {
+		log.Printf("Running: %q, %q ...", ssh, argv)
+	}
+
+	return execSSH(ssh, argv)
+}
+
+func writeKnownHosts(st *ipnstate.Status) (knownHostsFile string, err error) {
+	confDir, err := os.UserConfigDir()
+	if err != nil {
+		return "", err
+	}
+	tsConfDir := filepath.Join(confDir, "tailscale")
+	if err := os.MkdirAll(tsConfDir, 0700); err != nil {
+		return "", err
+	}
+	knownHostsFile = filepath.Join(tsConfDir, "ssh_known_hosts")
+	want := genKnownHosts(st)
+	if cur, err := os.ReadFile(knownHostsFile); err != nil || !bytes.Equal(cur, want) {
+		if err := os.WriteFile(knownHostsFile, want, 0644); err != nil {
+			return "", err
+		}
+	}
+	return knownHostsFile, nil
+}
+
+func genKnownHosts(st *ipnstate.Status) []byte {
+	var buf bytes.Buffer
+	for _, k := range st.Peers() {
+		ps := st.Peer[k]
+		for _, hk := range ps.SSH_HostKeys {
+			hostKey := strings.TrimSpace(hk)
+			if strings.ContainsAny(hostKey, "\n\r") { // invalid
+				continue
+			}
+			fmt.Fprintf(&buf, "%s %s\n", ps.DNSName, hostKey)
+		}
+	}
+	return buf.Bytes()
+}
+
+// nodeDNSNameFromArg returns the PeerStatus.DNSName value from a peer
+// in st that matches the input arg which can be a base name, full
+// DNS name, or an IP.
+func nodeDNSNameFromArg(st *ipnstate.Status, arg string) (dnsName string, ok bool) {
+	if arg == "" {
+		return
+	}
+	argIP, _ := netip.ParseAddr(arg)
+	for _, ps := range st.Peer {
+		dnsName = ps.DNSName
+		if argIP.IsValid() {
+			for _, ip := range ps.TailscaleIPs {
+				if ip == argIP {
+					return dnsName, true
+				}
+			}
+			continue
+		}
+		if strings.EqualFold(strings.TrimSuffix(arg, "."), strings.TrimSuffix(dnsName, ".")) {
+			return dnsName, true
+		}
+		if base, _, ok := strings.Cut(ps.DNSName, "."); ok && strings.EqualFold(base, arg) {
+			return dnsName, true
+		}
+	}
+	return "", false
+}
+
+// getSSHClientEnvVar returns the "SSH_CLIENT" environment variable
+// for the current process group, if any.
+var getSSHClientEnvVar = func() string {
+	return ""
+}
+
+// isSSHOverTailscale checks if the invocation is in a SSH session over Tailscale.
+// It is used to detect if the user is about to take an action that might result in them
+// disconnecting from the machine (e.g. disabling SSH)
+func isSSHOverTailscale() bool {
+	sshClient := getSSHClientEnvVar()
+	if sshClient == "" {
+		return false
+	}
+	ipStr, _, ok := strings.Cut(sshClient, " ")
+	if !ok {
+		return false
+	}
+	ip, err := netip.ParseAddr(ipStr)
+	if err != nil {
+		return false
+	}
+	return tsaddr.IsTailscaleIP(ip)
+}

cmd/tailscale/cli/ssh_exec.go

@@ -0,0 +1,26 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !windows
+// +build !windows
+
+package cli
+
+import (
+	"errors"
+	"os"
+	"os/exec"
+	"syscall"
+)
+
+func findSSH() (string, error) {
+	return exec.LookPath("ssh")
+}
+
+func execSSH(ssh string, argv []string) error {
+	if err := syscall.Exec(ssh, argv, os.Environ()); err != nil {
+		return err
+	}
+	return errors.New("unreachable")
+}

cmd/tailscale/cli/ssh_exec_windows.go

@@ -0,0 +1,38 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cli
+
+import (
+	"errors"
+	"os"
+	"os/exec"
+	"path/filepath"
+)
+
+func findSSH() (string, error) {
+	// use C:\Windows\System32\OpenSSH\ssh.exe since unexpected behavior
+	// occured with ssh.exe provided by msys2/cygwin and other environments.
+	if systemRoot := os.Getenv("SystemRoot"); systemRoot != "" {
+		exe := filepath.Join(systemRoot, "System32", "OpenSSH", "ssh.exe")
+		if st, err := os.Stat(exe); err == nil && !st.IsDir() {
+			return exe, nil
+		}
+	}
+	return exec.LookPath("ssh")
+}
+
+func execSSH(ssh string, argv []string) error {
+	// Don't use syscall.Exec on Windows, it's not fully implemented.
+	cmd := exec.Command(ssh, argv[1:]...)
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	var ee *exec.ExitError
+	err := cmd.Run()
+	if errors.As(err, &ee) {
+		os.Exit(ee.ExitCode())
+	}
+	return err
+}

cmd/tailscale/cli/ssh_unix.go

@@ -0,0 +1,51 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !js && !windows
+// +build !js,!windows
+
+package cli
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+
+	"golang.org/x/sys/unix"
+)
+
+func init() {
+	getSSHClientEnvVar = func() string {
+		if os.Getenv("SUDO_USER") == "" {
+			// No sudo, just check the env.
+			return os.Getenv("SSH_CLIENT")
+		}
+		if runtime.GOOS != "linux" {
+			// TODO(maisem): implement this for other platforms. It's not clear
+			// if there is a way to get the environment for a given process on
+			// darwin and bsd.
+			return ""
+		}
+		// SID is the session ID of the user's login session.
+		// It is also the process ID of the original shell that the user logged in with.
+		// We only need to check the environment of that process.
+		sid, err := unix.Getsid(os.Getpid())
+		if err != nil {
+			return ""
+		}
+		b, err := os.ReadFile(filepath.Join("/proc", strconv.Itoa(sid), "environ"))
+		if err != nil {
+			return ""
+		}
+		prefix := []byte("SSH_CLIENT=")
+		for _, env := range bytes.Split(b, []byte{0}) {
+			if bytes.HasPrefix(env, prefix) {
+				return string(env[len(prefix):])
+			}
+		}
+		return ""
+	}
+}

cmd/tailscale/cli/status.go

@@ -8,17 +8,17 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"flag"
 	"fmt"
 	"net"
 	"net/http"
+	"net/netip"
 	"os"
 	"strings"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
 	"github.com/toqueteos/webbrowser"
-	"inet.af/netaddr"
-	"tailscale.com/client/tailscale"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/net/interfaces"
@@ -46,7 +46,7 @@ https://github.com/tailscale/tailscale/blob/main/ipn/ipnstate/ipnstate.go
 `),
 	Exec: runStatus,
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("status")
+		fs := flag.NewFlagSet("status", flag.ExitOnError)
 		fs.BoolVar(&statusArgs.json, "json", false, "output in JSON format (WARNING: format subject to change)")
 		fs.BoolVar(&statusArgs.web, "web", false, "run webserver with HTML showing status")
 		fs.BoolVar(&statusArgs.active, "active", false, "filter output to only peers with active sessions (not applicable to web mode)")
@@ -69,7 +69,14 @@ var statusArgs struct {
 }
 
 func runStatus(ctx context.Context, args []string) error {
-	st, err := tailscale.Status(ctx)
+	if len(args) > 0 {
+		return errors.New("unexpected non-flag arguments to 'tailscale status'")
+	}
+	getStatus := localClient.Status
+	if !statusArgs.peers {
+		getStatus = localClient.StatusWithoutPeers
+	}
+	st, err := getStatus(ctx)
 	if err != nil {
 		return fixTailscaledConnectError(err)
 	}
@@ -85,7 +92,7 @@ func runStatus(ctx context.Context, args []string) error {
 		if err != nil {
 			return err
 		}
-		printf("%s", j)
+		fmt.Printf("%s", j)
 		return nil
 	}
 	if statusArgs.web {
@@ -94,7 +101,7 @@ func runStatus(ctx context.Context, args []string) error {
 			return err
 		}
 		statusURL := interfaces.HTTPOfListener(ln)
-		printf("Serving Tailscale status at %v ...\n", statusURL)
+		fmt.Printf("Serving Tailscale status at %v ...\n", statusURL)
 		go func() {
 			<-ctx.Done()
 			ln.Close()
@@ -107,7 +114,7 @@ func runStatus(ctx context.Context, args []string) error {
 				http.NotFound(w, r)
 				return
 			}
-			st, err := tailscale.Status(ctx)
+			st, err := localClient.Status(ctx)
 			if err != nil {
 				http.Error(w, err.Error(), 500)
 				return
@@ -121,22 +128,24 @@ func runStatus(ctx context.Context, args []string) error {
 		return err
 	}
 
+	// print health check information prior to checking LocalBackend state as
+	// it may provide an explanation to the user if we choose to exit early
+	if len(st.Health) > 0 {
+		fmt.Printf("# Health check:\n")
+		for _, m := range st.Health {
+			fmt.Printf("#     - %s\n", m)
+		}
+		fmt.Println()
+	}
+
 	description, ok := isRunningOrStarting(st)
 	if !ok {
-		outln(description)
+		fmt.Println(description)
 		os.Exit(1)
 	}
 
-	if len(st.Health) > 0 {
-		printf("# Health check:\n")
-		for _, m := range st.Health {
-			printf("#     - %s\n", m)
-		}
-		outln()
-	}
-
 	var buf bytes.Buffer
-	f := func(format string, a ...interface{}) { fmt.Fprintf(&buf, format, a...) }
+	f := func(format string, a ...any) { fmt.Fprintf(&buf, format, a...) }
 	printPS := func(ps *ipnstate.PeerStatus) {
 		f("%-15s %-20s %-12s %-7s ",
 			firstIPString(ps.TailscaleIPs),
@@ -204,7 +213,7 @@ func runStatus(ctx context.Context, args []string) error {
 			printPS(ps)
 		}
 	}
-	Stdout.Write(buf.Bytes())
+	os.Stdout.Write(buf.Bytes())
 	return nil
 }
 
@@ -251,7 +260,7 @@ func ownerLogin(st *ipnstate.Status, ps *ipnstate.PeerStatus) string {
 	return u.LoginName
 }
 
-func firstIPString(v []netaddr.IP) string {
+func firstIPString(v []netip.Addr) string {
 	if len(v) == 0 {
 		return ""
 	}

cmd/tailscale/cli/up.go

@@ -7,31 +7,31 @@ package cli
 import (
 	"context"
 	"encoding/base64"
+	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"flag"
 	"fmt"
 	"log"
+	"net/netip"
 	"os"
 	"reflect"
 	"runtime"
 	"sort"
 	"strings"
 	"sync"
+	"time"
 
 	shellquote "github.com/kballard/go-shellquote"
 	"github.com/peterbourgon/ff/v3/ffcli"
 	qrcode "github.com/skip2/go-qrcode"
-	"inet.af/netaddr"
-	"tailscale.com/client/tailscale"
-	"tailscale.com/envknob"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/net/tsaddr"
 	"tailscale.com/safesocket"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/logger"
 	"tailscale.com/types/preftype"
-	"tailscale.com/util/dnsname"
 	"tailscale.com/version"
 	"tailscale.com/version/distro"
 )
@@ -52,7 +52,7 @@ down").
 If flags are specified, the flags must be the complete set of desired
 settings. An error is returned if any setting would be changed as a
 result of an unspecified flag's default value, unless the --reset flag
-is also used. (The flags --authkey, --force-reauth, and --qr are not
+is also used. (The flags --auth-key, --force-reauth, and --qr are not
 considered settings that need to be re-specified when modifying
 settings.)
 `),
@@ -85,7 +85,7 @@ var upFlagSet = newUpFlagSet(effectiveGOOS(), &upArgs)
 func inTest() bool { return flag.Lookup("test.v") != nil }
 
 func newUpFlagSet(goos string, upArgs *upArgsT) *flag.FlagSet {
-	upf := newFlagSet("up")
+	upf := flag.NewFlagSet("up", flag.ExitOnError)
 
 	upf.BoolVar(&upArgs.qr, "qr", false, "show QR code for login URLs")
 	upf.BoolVar(&upArgs.json, "json", false, "output in JSON format (WARNING: format subject to change)")
@@ -99,11 +99,9 @@ func newUpFlagSet(goos string, upArgs *upArgsT) *flag.FlagSet {
 	upf.StringVar(&upArgs.exitNodeIP, "exit-node", "", "Tailscale exit node (IP or base name) for internet traffic, or empty string to not use an exit node")
 	upf.BoolVar(&upArgs.exitNodeAllowLANAccess, "exit-node-allow-lan-access", false, "Allow direct access to the local network when routing traffic via an exit node")
 	upf.BoolVar(&upArgs.shieldsUp, "shields-up", false, "don't allow incoming connections")
-	if envknob.UseWIPCode() || inTest() {
-		upf.BoolVar(&upArgs.runSSH, "ssh", false, "run an SSH server, permitting access per tailnet admin's declared policy")
-	}
+	upf.BoolVar(&upArgs.runSSH, "ssh", false, "run an SSH server, permitting access per tailnet admin's declared policy")
 	upf.StringVar(&upArgs.advertiseTags, "advertise-tags", "", "comma-separated ACL tags to request; each must start with \"tag:\" (e.g. \"tag:eng,tag:montreal,tag:ssh\")")
-	upf.StringVar(&upArgs.authKeyOrFile, "authkey", "", `node authorization key; if it begins with "file:", then it's a path to a file containing the authkey`)
+	upf.StringVar(&upArgs.authKeyOrFile, "auth-key", "", `node authorization key; if it begins with "file:", then it's a path to a file containing the authkey`)
 	upf.StringVar(&upArgs.hostname, "hostname", "", "hostname to use instead of the one provided by the OS")
 	upf.StringVar(&upArgs.advertiseRoutes, "advertise-routes", "", "routes to advertise to other nodes (comma-separated, e.g. \"10.0.0.0/8,192.168.0.0/24\") or empty string to not advertise routes")
 	upf.BoolVar(&upArgs.advertiseDefaultRoute, "advertise-exit-node", false, "offer to be an exit node for internet traffic for the tailnet")
@@ -117,6 +115,8 @@ func newUpFlagSet(goos string, upArgs *upArgsT) *flag.FlagSet {
 	case "windows":
 		upf.BoolVar(&upArgs.forceDaemon, "unattended", false, "run in \"Unattended Mode\" where Tailscale keeps running even after the current GUI user logs out (Windows-only)")
 	}
+	upf.DurationVar(&upArgs.timeout, "timeout", 0, "maximum amount of time to wait for tailscaled to enter a Running state; default (0s) blocks forever")
+	registerAcceptRiskFlag(upf)
 	return upf
 }
 
@@ -149,6 +149,7 @@ type upArgsT struct {
 	hostname               string
 	opUser                 string
 	json                   bool
+	timeout                time.Duration
 }
 
 func (a upArgsT) getAuthKey() (string, error) {
@@ -193,28 +194,53 @@ type upOutputJSON struct {
 	Error        string `json:",omitempty"` // description of an error
 }
 
-func warnf(format string, args ...interface{}) {
-	printf("Warning: "+format+"\n", args...)
+func warnf(format string, args ...any) {
+	fmt.Printf("Warning: "+format+"\n", args...)
 }
 
 var (
-	ipv4default = netaddr.MustParseIPPrefix("0.0.0.0/0")
-	ipv6default = netaddr.MustParseIPPrefix("::/0")
+	ipv4default = netip.MustParsePrefix("0.0.0.0/0")
+	ipv6default = netip.MustParsePrefix("::/0")
 )
 
-func calcAdvertiseRoutes(advertiseRoutes string, advertiseDefaultRoute bool) ([]netaddr.IPPrefix, error) {
-	routeMap := map[netaddr.IPPrefix]bool{}
+func validateViaPrefix(ipp netip.Prefix) error {
+	if !tsaddr.IsViaPrefix(ipp) {
+		return fmt.Errorf("%v is not a 4-in-6 prefix", ipp)
+	}
+	if ipp.Bits() < (128 - 32) {
+		return fmt.Errorf("%v 4-in-6 prefix must be at least a /%v", ipp, 128-32)
+	}
+	a := ipp.Addr().As16()
+	// The first 64 bits of a are the via prefix.
+	// The next 32 bits are the "site ID".
+	// The last 32 bits are the IPv4.
+	// For now, we reserve the top 3 bytes of the site ID,
+	// and only allow users to use site IDs 0-255.
+	siteID := binary.BigEndian.Uint32(a[8:12])
+	if siteID > 0xFF {
+		return fmt.Errorf("route %v contains invalid site ID %08x; must be 0xff or less", ipp, siteID)
+	}
+	return nil
+}
+
+func calcAdvertiseRoutes(advertiseRoutes string, advertiseDefaultRoute bool) ([]netip.Prefix, error) {
+	routeMap := map[netip.Prefix]bool{}
 	if advertiseRoutes != "" {
 		var default4, default6 bool
 		advroutes := strings.Split(advertiseRoutes, ",")
 		for _, s := range advroutes {
-			ipp, err := netaddr.ParseIPPrefix(s)
+			ipp, err := netip.ParsePrefix(s)
 			if err != nil {
 				return nil, fmt.Errorf("%q is not a valid IP address or CIDR prefix", s)
 			}
 			if ipp != ipp.Masked() {
 				return nil, fmt.Errorf("%s has non-address bits set; expected %s", ipp, ipp.Masked())
 			}
+			if tsaddr.IsViaPrefix(ipp) {
+				if err := validateViaPrefix(ipp); err != nil {
+					return nil, err
+				}
+			}
 			if ipp == ipv4default {
 				default4 = true
 			} else if ipp == ipv6default {
@@ -229,10 +255,10 @@ func calcAdvertiseRoutes(advertiseRoutes string, advertiseDefaultRoute bool) ([]
 		}
 	}
 	if advertiseDefaultRoute {
-		routeMap[netaddr.MustParseIPPrefix("0.0.0.0/0")] = true
-		routeMap[netaddr.MustParseIPPrefix("::/0")] = true
+		routeMap[netip.MustParsePrefix("0.0.0.0/0")] = true
+		routeMap[netip.MustParsePrefix("::/0")] = true
 	}
-	routes := make([]netaddr.IPPrefix, 0, len(routeMap))
+	routes := make([]netip.Prefix, 0, len(routeMap))
 	for r := range routeMap {
 		routes = append(routes, r)
 	}
@@ -240,70 +266,11 @@ func calcAdvertiseRoutes(advertiseRoutes string, advertiseDefaultRoute bool) ([]
 		if routes[i].Bits() != routes[j].Bits() {
 			return routes[i].Bits() < routes[j].Bits()
 		}
-		return routes[i].IP().Less(routes[j].IP())
+		return routes[i].Addr().Less(routes[j].Addr())
 	})
 	return routes, nil
 }
 
-// peerWithTailscaleIP returns the peer in st with the provided
-// Tailscale IP.
-func peerWithTailscaleIP(st *ipnstate.Status, ip netaddr.IP) (ps *ipnstate.PeerStatus, ok bool) {
-	for _, ps := range st.Peer {
-		for _, ip2 := range ps.TailscaleIPs {
-			if ip == ip2 {
-				return ps, true
-			}
-		}
-	}
-	return nil, false
-}
-
-// exitNodeIPOfArg maps from a user-provided CLI flag value to an IP
-// address they want to use as an exit node.
-func exitNodeIPOfArg(arg string, st *ipnstate.Status) (ip netaddr.IP, err error) {
-	if arg == "" {
-		return ip, errors.New("invalid use of exitNodeIPOfArg with empty string")
-	}
-	ip, err = netaddr.ParseIP(arg)
-	if err == nil {
-		// If we're online already and have a netmap, double check that the IP
-		// address specified is valid.
-		if st.BackendState == "Running" {
-			ps, ok := peerWithTailscaleIP(st, ip)
-			if !ok {
-				return ip, fmt.Errorf("no node found in netmap with IP %v", ip)
-			}
-			if !ps.ExitNodeOption {
-				return ip, fmt.Errorf("node %v is not advertising an exit node", ip)
-			}
-		}
-		return ip, err
-	}
-	match := 0
-	for _, ps := range st.Peer {
-		baseName := dnsname.TrimSuffix(ps.DNSName, st.MagicDNSSuffix)
-		if !strings.EqualFold(arg, baseName) {
-			continue
-		}
-		match++
-		if len(ps.TailscaleIPs) == 0 {
-			return ip, fmt.Errorf("node %q has no Tailscale IP?", arg)
-		}
-		if !ps.ExitNodeOption {
-			return ip, fmt.Errorf("node %q is not advertising an exit node", arg)
-		}
-		ip = ps.TailscaleIPs[0]
-	}
-	switch match {
-	case 0:
-		return ip, fmt.Errorf("invalid value %q for --exit-node; must be IP or unique node name", arg)
-	case 1:
-		return ip, nil
-	default:
-		return ip, fmt.Errorf("ambiguous exit node name %q", arg)
-	}
-}
-
 // prefsFromUpArgs returns the ipn.Prefs for the provided args.
 //
 // Note that the parameters upArgs and warnf are named intentionally
@@ -316,25 +283,10 @@ func prefsFromUpArgs(upArgs upArgsT, warnf logger.Logf, st *ipnstate.Status, goo
 		return nil, err
 	}
 
-	var exitNodeIP netaddr.IP
-	if upArgs.exitNodeIP != "" {
-		var err error
-		exitNodeIP, err = exitNodeIPOfArg(upArgs.exitNodeIP, st)
-		if err != nil {
-			return nil, err
-		}
-	} else if upArgs.exitNodeAllowLANAccess {
+	if upArgs.exitNodeIP == "" && upArgs.exitNodeAllowLANAccess {
 		return nil, fmt.Errorf("--exit-node-allow-lan-access can only be used with --exit-node")
 	}
 
-	if upArgs.exitNodeIP != "" {
-		for _, ip := range st.TailscaleIPs {
-			if exitNodeIP == ip {
-				return nil, fmt.Errorf("cannot use %s as the exit node as it is a local IP address to this machine, did you mean --advertise-exit-node?", upArgs.exitNodeIP)
-			}
-		}
-	}
-
 	var tags []string
 	if upArgs.advertiseTags != "" {
 		tags = strings.Split(upArgs.advertiseTags, ",")
@@ -354,7 +306,17 @@ func prefsFromUpArgs(upArgs upArgsT, warnf logger.Logf, st *ipnstate.Status, goo
 	prefs.ControlURL = upArgs.server
 	prefs.WantRunning = true
 	prefs.RouteAll = upArgs.acceptRoutes
-	prefs.ExitNodeIP = exitNodeIP
+
+	if upArgs.exitNodeIP != "" {
+		if err := prefs.SetExitNodeIP(upArgs.exitNodeIP, st); err != nil {
+			var e ipn.ExitNodeLocalIPError
+			if errors.As(err, &e) {
+				return nil, fmt.Errorf("%w; did you mean --advertise-exit-node?", err)
+			}
+			return nil, err
+		}
+	}
+
 	prefs.ExitNodeAllowLANAccess = upArgs.exitNodeAllowLANAccess
 	prefs.CorpDNS = upArgs.acceptDNS
 	prefs.AllowSingleHosts = upArgs.singleRoutes
@@ -400,7 +362,7 @@ func prefsFromUpArgs(upArgs upArgsT, warnf logger.Logf, st *ipnstate.Status, goo
 // without changing any settings.
 func updatePrefs(prefs, curPrefs *ipn.Prefs, env upCheckEnv) (simpleUp bool, justEditMP *ipn.MaskedPrefs, err error) {
 	if !env.upArgs.reset {
-		applyImplicitPrefs(prefs, curPrefs, env.user)
+		applyImplicitPrefs(prefs, curPrefs, env)
 
 		if err := checkForAccidentalSettingReverts(prefs, curPrefs, env); err != nil {
 			return false, nil, err
@@ -442,12 +404,12 @@ func updatePrefs(prefs, curPrefs *ipn.Prefs, env upCheckEnv) (simpleUp bool, jus
 	return simpleUp, justEditMP, nil
 }
 
-func runUp(ctx context.Context, args []string) error {
+func runUp(ctx context.Context, args []string) (retErr error) {
 	if len(args) > 0 {
 		fatalf("too many non-flag arguments: %q", args)
 	}
 
-	st, err := tailscale.Status(ctx)
+	st, err := localClient.Status(ctx)
 	if err != nil {
 		return fixTailscaledConnectError(err)
 	}
@@ -488,12 +450,12 @@ func runUp(ctx context.Context, args []string) error {
 	}
 
 	if len(prefs.AdvertiseRoutes) > 0 {
-		if err := tailscale.CheckIPForwarding(context.Background()); err != nil {
+		if err := localClient.CheckIPForwarding(context.Background()); err != nil {
 			warnf("%v", err)
 		}
 	}
 
-	curPrefs, err := tailscale.GetPrefs(ctx)
+	curPrefs, err := localClient.GetPrefs(ctx)
 	if err != nil {
 		return err
 	}
@@ -507,12 +469,30 @@ func runUp(ctx context.Context, args []string) error {
 		backendState:  st.BackendState,
 		curExitNodeIP: exitNodeIP(curPrefs, st),
 	}
+
+	if upArgs.runSSH != curPrefs.RunSSH && isSSHOverTailscale() {
+		if upArgs.runSSH {
+			err = presentRiskToUser(riskLoseSSH, `You are connected over Tailscale; this action will reroute SSH traffic to Tailscale SSH and will result in your session disconnecting.`)
+		} else {
+			err = presentRiskToUser(riskLoseSSH, `You are connected using Tailscale SSH; this action will result in your session disconnecting.`)
+		}
+		if err != nil {
+			return err
+		}
+	}
+
+	defer func() {
+		if retErr == nil {
+			checkSSHUpWarnings(ctx)
+		}
+	}()
+
 	simpleUp, justEditMP, err := updatePrefs(prefs, curPrefs, env)
 	if err != nil {
 		fatalf("%s", err)
 	}
 	if justEditMP != nil {
-		_, err := tailscale.EditPrefs(ctx, justEditMP)
+		_, err := localClient.EditPrefs(ctx, justEditMP)
 		return err
 	}
 
@@ -558,7 +538,7 @@ func runUp(ctx context.Context, args []string) error {
 				if env.upArgs.json {
 					printUpDoneJSON(ipn.NeedsMachineAuth, "")
 				} else {
-					fmt.Fprintf(Stderr, "\nTo authorize your machine, visit (as admin):\n\n\t%s\n\n", prefs.AdminPageURL())
+					fmt.Fprintf(os.Stderr, "\nTo authorize your machine, visit (as admin):\n\n\t%s\n\n", prefs.AdminPageURL())
 				}
 			case ipn.Running:
 				// Done full authentication process
@@ -566,7 +546,7 @@ func runUp(ctx context.Context, args []string) error {
 					printUpDoneJSON(ipn.Running, "")
 				} else if printed {
 					// Only need to print an update if we printed the "please click" message earlier.
-					fmt.Fprintf(Stderr, "Success.\n")
+					fmt.Fprintf(os.Stderr, "Success.\n")
 				}
 				select {
 				case running <- true:
@@ -595,13 +575,13 @@ func runUp(ctx context.Context, args []string) error {
 					fmt.Println(string(data))
 				}
 			} else {
-				fmt.Fprintf(Stderr, "\nTo authenticate, visit:\n\n\t%s\n\n", *url)
+				fmt.Fprintf(os.Stderr, "\nTo authenticate, visit:\n\n\t%s\n\n", *url)
 				if upArgs.qr {
 					q, err := qrcode.New(*url, qrcode.Medium)
 					if err != nil {
 						log.Printf("QR code error: %v", err)
 					} else {
-						fmt.Fprintf(Stderr, "%s\n", q.ToString(false))
+						fmt.Fprintf(os.Stderr, "%s\n", q.ToString(false))
 					}
 				}
 			}
@@ -623,7 +603,7 @@ func runUp(ctx context.Context, args []string) error {
 	// Special case: bare "tailscale up" means to just start
 	// running, if there's ever been a login.
 	if simpleUp {
-		_, err := tailscale.EditPrefs(ctx, &ipn.MaskedPrefs{
+		_, err := localClient.EditPrefs(ctx, &ipn.MaskedPrefs{
 			Prefs: ipn.Prefs{
 				WantRunning: true,
 			},
@@ -633,6 +613,10 @@ func runUp(ctx context.Context, args []string) error {
 			return err
 		}
 	} else {
+		if err := localClient.CheckPrefs(ctx, prefs); err != nil {
+			return err
+		}
+
 		authKey, err := upArgs.getAuthKey()
 		if err != nil {
 			return err
@@ -670,6 +654,12 @@ func runUp(ctx context.Context, args []string) error {
 	// need to prioritize reads from 'running' if it's
 	// readable; its send does happen before the pump mechanism
 	// shuts down. (Issue 2333)
+	var timeoutCh <-chan time.Time
+	if upArgs.timeout > 0 {
+		timeoutTimer := time.NewTimer(upArgs.timeout)
+		defer timeoutTimer.Stop()
+		timeoutCh = timeoutTimer.C
+	}
 	select {
 	case <-running:
 		return nil
@@ -687,6 +677,30 @@ func runUp(ctx context.Context, args []string) error {
 		default:
 		}
 		return err
+	case <-timeoutCh:
+		return errors.New(`timeout waiting for Tailscale service to enter a Running state; check health with "tailscale status"`)
+	}
+}
+
+func checkSSHUpWarnings(ctx context.Context) {
+	if !upArgs.runSSH {
+		return
+	}
+	st, err := localClient.Status(ctx)
+	if err != nil {
+		// Ignore. Don't spam more.
+		return
+	}
+	if len(st.Health) == 0 {
+		return
+	}
+	if len(st.Health) == 1 && strings.Contains(st.Health[0], "SSH") {
+		fmt.Printf("%s\n", st.Health[0])
+		return
+	}
+	fmt.Printf("# Health check:\n")
+	for _, m := range st.Health {
+		fmt.Printf("    - %s\n", m)
 	}
 }
 
@@ -743,7 +757,7 @@ func addPrefFlagMapping(flagName string, prefNames ...string) {
 // correspond to an ipn.Pref.
 func preflessFlag(flagName string) bool {
 	switch flagName {
-	case "authkey", "force-reauth", "reset", "qr", "json":
+	case "auth-key", "force-reauth", "reset", "qr", "json", "timeout", "accept-risk":
 		return true
 	}
 	return false
@@ -776,7 +790,7 @@ type upCheckEnv struct {
 	flagSet       *flag.FlagSet
 	upArgs        upArgsT
 	backendState  string
-	curExitNodeIP netaddr.IP
+	curExitNodeIP netip.Addr
 	distro        distro.Distro
 }
 
@@ -867,13 +881,20 @@ func checkForAccidentalSettingReverts(newPrefs, curPrefs *ipn.Prefs, env upCheck
 	return errors.New(sb.String())
 }
 
-// applyImplicitPrefs mutates prefs to add implicit preferences. Currently
-// this is just the operator user, which only needs to be set if it doesn't
+// applyImplicitPrefs mutates prefs to add implicit preferences for the user operator.
+// If the operator flag is passed no action is taken, otherwise this only needs to be set if it doesn't
 // match the current user.
 //
 // curUser is os.Getenv("USER"). It's pulled out for testability.
-func applyImplicitPrefs(prefs, oldPrefs *ipn.Prefs, curUser string) {
-	if prefs.OperatorUser == "" && oldPrefs.OperatorUser == curUser {
+func applyImplicitPrefs(prefs, oldPrefs *ipn.Prefs, env upCheckEnv) {
+	explicitOperator := false
+	env.flagSet.Visit(func(f *flag.Flag) {
+		if f.Name == "operator" {
+			explicitOperator = true
+		}
+	})
+
+	if prefs.OperatorUser == "" && oldPrefs.OperatorUser == env.user && !explicitOperator {
 		prefs.OperatorUser = oldPrefs.OperatorUser
 	}
 }
@@ -888,14 +909,14 @@ func flagAppliesToOS(flag, goos string) bool {
 	return true
 }
 
-func prefsToFlags(env upCheckEnv, prefs *ipn.Prefs) (flagVal map[string]interface{}) {
-	ret := make(map[string]interface{})
+func prefsToFlags(env upCheckEnv, prefs *ipn.Prefs) (flagVal map[string]any) {
+	ret := make(map[string]any)
 
 	exitNodeIPStr := func() string {
-		if !prefs.ExitNodeIP.IsZero() {
+		if prefs.ExitNodeIP.IsValid() {
 			return prefs.ExitNodeIP.String()
 		}
-		if prefs.ExitNodeID.IsZero() || env.curExitNodeIP.IsZero() {
+		if prefs.ExitNodeID.IsZero() || !env.curExitNodeIP.IsValid() {
 			return ""
 		}
 		return env.curExitNodeIP.String()
@@ -906,7 +927,7 @@ func prefsToFlags(env upCheckEnv, prefs *ipn.Prefs) (flagVal map[string]interfac
 		if preflessFlag(f.Name) {
 			return
 		}
-		set := func(v interface{}) {
+		set := func(v any) {
 			if flagAppliesToOS(f.Name, env.goos) {
 				ret[f.Name] = v
 			} else {
@@ -960,7 +981,7 @@ func prefsToFlags(env upCheckEnv, prefs *ipn.Prefs) (flagVal map[string]interfac
 	return ret
 }
 
-func fmtFlagValueArg(flagName string, val interface{}) string {
+func fmtFlagValueArg(flagName string, val any) string {
 	if val == true {
 		return "--" + flagName
 	}
@@ -970,13 +991,13 @@ func fmtFlagValueArg(flagName string, val interface{}) string {
 	return fmt.Sprintf("--%s=%v", flagName, shellquote.Join(fmt.Sprint(val)))
 }
 
-func hasExitNodeRoutes(rr []netaddr.IPPrefix) bool {
+func hasExitNodeRoutes(rr []netip.Prefix) bool {
 	var v4, v6 bool
 	for _, r := range rr {
 		if r.Bits() == 0 {
-			if r.IP().Is4() {
+			if r.Addr().Is4() {
 				v4 = true
-			} else if r.IP().Is6() {
+			} else if r.Addr().Is6() {
 				v6 = true
 			}
 		}
@@ -987,11 +1008,11 @@ func hasExitNodeRoutes(rr []netaddr.IPPrefix) bool {
 // withoutExitNodes returns rr unchanged if it has only 1 or 0 /0
 // routes. If it has both IPv4 and IPv6 /0 routes, then it returns
 // a copy with all /0 routes removed.
-func withoutExitNodes(rr []netaddr.IPPrefix) []netaddr.IPPrefix {
+func withoutExitNodes(rr []netip.Prefix) []netip.Prefix {
 	if !hasExitNodeRoutes(rr) {
 		return rr
 	}
-	var out []netaddr.IPPrefix
+	var out []netip.Prefix
 	for _, r := range rr {
 		if r.Bits() > 0 {
 			out = append(out, r)
@@ -1002,11 +1023,11 @@ func withoutExitNodes(rr []netaddr.IPPrefix) []netaddr.IPPrefix {
 
 // exitNodeIP returns the exit node IP from p, using st to map
 // it from its ID form to an IP address if needed.
-func exitNodeIP(p *ipn.Prefs, st *ipnstate.Status) (ip netaddr.IP) {
+func exitNodeIP(p *ipn.Prefs, st *ipnstate.Status) (ip netip.Addr) {
 	if p == nil {
 		return
 	}
-	if !p.ExitNodeIP.IsZero() {
+	if p.ExitNodeIP.IsValid() {
 		return p.ExitNodeIP
 	}
 	id := p.ExitNodeID

cmd/tailscale/cli/version.go

@@ -10,7 +10,6 @@ import (
 	"fmt"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"tailscale.com/client/tailscale"
 	"tailscale.com/version"
 )
 
@@ -19,7 +18,7 @@ var versionCmd = &ffcli.Command{
 	ShortUsage: "version [flags]",
 	ShortHelp:  "Print Tailscale version",
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("version")
+		fs := flag.NewFlagSet("version", flag.ExitOnError)
 		fs.BoolVar(&versionArgs.daemon, "daemon", false, "also print local node's daemon version")
 		return fs
 	})(),
@@ -35,16 +34,16 @@ func runVersion(ctx context.Context, args []string) error {
 		return fmt.Errorf("too many non-flag arguments: %q", args)
 	}
 	if !versionArgs.daemon {
-		outln(version.String())
+		fmt.Println(version.String())
 		return nil
 	}
 
-	printf("Client: %s\n", version.String())
+	fmt.Printf("Client: %s\n", version.String())
 
-	st, err := tailscale.StatusWithoutPeers(ctx)
+	st, err := localClient.StatusWithoutPeers(ctx)
 	if err != nil {
 		return err
 	}
-	printf("Daemon: %s\n", st.Version)
+	fmt.Printf("Daemon: %s\n", st.Version)
 	return nil
 }

cmd/tailscale/cli/web.go

@@ -20,6 +20,7 @@ import (
 	"net"
 	"net/http"
 	"net/http/cgi"
+	"net/netip"
 	"net/url"
 	"os"
 	"os/exec"
@@ -27,8 +28,6 @@ import (
 	"strings"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
-	"inet.af/netaddr"
-	"tailscale.com/client/tailscale"
 	"tailscale.com/ipn"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/preftype"
@@ -76,7 +75,7 @@ Tailscale, as opposed to a CLI or a native app.
 `),
 
 	FlagSet: (func() *flag.FlagSet {
-		webf := newFlagSet("web")
+		webf := flag.NewFlagSet("web", flag.ExitOnError)
 		webf.StringVar(&webArgs.listen, "listen", "localhost:8088", "listen address; use port 0 for automatic")
 		webf.BoolVar(&webArgs.cgi, "cgi", false, "run as CGI script")
 		return webf
@@ -209,12 +208,20 @@ func qnapAuthn(r *http.Request) (string, *qnapAuthResponse, error) {
 		return "", nil, err
 	}
 	token, err := r.Cookie("qtoken")
-	if err != nil {
-		return "", nil, err
+	if err == nil {
+		return qnapAuthnQtoken(r, user.Value, token.Value)
 	}
+	sid, err := r.Cookie("NAS_SID")
+	if err == nil {
+		return qnapAuthnSid(r, user.Value, sid.Value)
+	}
+	return "", nil, fmt.Errorf("not authenticated by any mechanism")
+}
+
+func qnapAuthnQtoken(r *http.Request, user, token string) (string, *qnapAuthResponse, error) {
 	query := url.Values{
-		"qtoken": []string{token.Value},
-		"user":   []string{user.Value},
+		"qtoken": []string{token},
+		"user":   []string{user},
 	}
 	u := url.URL{
 		Scheme:   r.URL.Scheme,
@@ -222,7 +229,26 @@ func qnapAuthn(r *http.Request) (string, *qnapAuthResponse, error) {
 		Path:     "/cgi-bin/authLogin.cgi",
 		RawQuery: query.Encode(),
 	}
-	resp, err := http.Get(u.String())
+
+	return qnapAuthnFinish(user, u.String())
+}
+
+func qnapAuthnSid(r *http.Request, user, sid string) (string, *qnapAuthResponse, error) {
+	query := url.Values{
+		"sid": []string{sid},
+	}
+	u := url.URL{
+		Scheme:   r.URL.Scheme,
+		Host:     r.URL.Host,
+		Path:     "/cgi-bin/authLogin.cgi",
+		RawQuery: query.Encode(),
+	}
+
+	return qnapAuthnFinish(user, u.String())
+}
+
+func qnapAuthnFinish(user, url string) (string, *qnapAuthResponse, error) {
+	resp, err := http.Get(url)
 	if err != nil {
 		return "", nil, err
 	}
@@ -238,7 +264,7 @@ func qnapAuthn(r *http.Request) (string, *qnapAuthResponse, error) {
 	if authResp.AuthPassed == 0 {
 		return "", nil, fmt.Errorf("not authenticated")
 	}
-	return user.Value, authResp, nil
+	return user, authResp, nil
 }
 
 func synoAuthn() (string, error) {
@@ -269,15 +295,14 @@ func synoTokenRedirect(w http.ResponseWriter, r *http.Request) bool {
 	}
 	// We need a SynoToken for authenticate.cgi.
 	// So we tell the client to get one.
-	serverURL := r.URL.Scheme + "://" + r.URL.Host
-	synoTokenRedirectHTML.Execute(w, serverURL)
+	_, _ = fmt.Fprint(w, synoTokenRedirectHTML)
 	return true
 }
 
-var synoTokenRedirectHTML = template.Must(template.New("redirect").Parse(`<html><body>
+const synoTokenRedirectHTML = `<html><body>
 Redirecting with session token...
 <script>
-var serverURL = {{ . }};
+var serverURL = window.location.protocol + "//" + window.location.host;
 var req = new XMLHttpRequest();
 req.overrideMimeType("application/json");
 req.open("GET", serverURL + "/webman/login.cgi", true);
@@ -289,7 +314,7 @@ req.onload = function() {
 req.send(null);
 </script>
 </body></html>
-`))
+`
 
 func webHandler(w http.ResponseWriter, r *http.Request) {
 	if authRedirect(w, r) {
@@ -313,13 +338,13 @@ func webHandler(w http.ResponseWriter, r *http.Request) {
 			AdvertiseExitNode bool
 			Reauthenticate    bool
 		}
-		type mi map[string]interface{}
+		type mi map[string]any
 		if err := json.NewDecoder(r.Body).Decode(&postData); err != nil {
 			w.WriteHeader(400)
 			json.NewEncoder(w).Encode(mi{"error": err.Error()})
 			return
 		}
-		prefs, err := tailscale.GetPrefs(r.Context())
+		prefs, err := localClient.GetPrefs(r.Context())
 		if err != nil && !postData.Reauthenticate {
 			w.WriteHeader(http.StatusInternalServerError)
 			json.NewEncoder(w).Encode(mi{"error": err.Error()})
@@ -349,12 +374,12 @@ func webHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	st, err := tailscale.Status(r.Context())
+	st, err := localClient.Status(r.Context())
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
-	prefs, err := tailscale.GetPrefs(r.Context())
+	prefs, err := localClient.GetPrefs(r.Context())
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
@@ -368,8 +393,8 @@ func webHandler(w http.ResponseWriter, r *http.Request) {
 		Status:       st.BackendState,
 		DeviceName:   deviceName,
 	}
-	exitNodeRouteV4 := netaddr.MustParseIPPrefix("0.0.0.0/0")
-	exitNodeRouteV6 := netaddr.MustParseIPPrefix("::/0")
+	exitNodeRouteV4 := netip.MustParsePrefix("0.0.0.0/0")
+	exitNodeRouteV6 := netip.MustParsePrefix("::/0")
 	for _, r := range prefs.AdvertiseRoutes {
 		if r == exitNodeRouteV4 || r == exitNodeRouteV6 {
 			data.AdvertiseExitNode = true
@@ -407,7 +432,7 @@ func tailscaleUp(ctx context.Context, prefs *ipn.Prefs, forceReauth bool) (authU
 		prefs.NetfilterMode = preftype.NetfilterOff
 	}
 
-	st, err := tailscale.Status(ctx)
+	st, err := localClient.Status(ctx)
 	if err != nil {
 		return "", fmt.Errorf("can't fetch status: %v", err)
 	}

cmd/tailscale/depaware.txt

@@ -1,11 +1,21 @@
 tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/depaware)
 
+        filippo.io/edwards25519                                      from github.com/hdevalence/ed25519consensus
+        filippo.io/edwards25519/field                                from filippo.io/edwards25519
    W 💣 github.com/alexbrainman/sspi                                 from github.com/alexbrainman/sspi/negotiate+
    W    github.com/alexbrainman/sspi/internal/common                 from github.com/alexbrainman/sspi/negotiate
    W 💣 github.com/alexbrainman/sspi/negotiate                       from tailscale.com/net/tshttpproxy
+        github.com/fxamacker/cbor/v2                                 from tailscale.com/tka
         github.com/golang/groupcache/lru                             from tailscale.com/net/dnscache
+        github.com/hdevalence/ed25519consensus                       from tailscale.com/tka
+   L    github.com/josharian/native                                  from github.com/mdlayher/netlink+
+   L 💣 github.com/jsimonetti/rtnetlink                              from tailscale.com/net/interfaces
+   L    github.com/jsimonetti/rtnetlink/internal/unix                from github.com/jsimonetti/rtnetlink
         github.com/kballard/go-shellquote                            from tailscale.com/cmd/tailscale/cli
-   L    github.com/klauspost/compress/flate                          from nhooyr.io/websocket
+        github.com/klauspost/compress/flate                          from nhooyr.io/websocket
+   L 💣 github.com/mdlayher/netlink                                  from github.com/jsimonetti/rtnetlink+
+   L 💣 github.com/mdlayher/netlink/nlenc                            from github.com/jsimonetti/rtnetlink+
+   L 💣 github.com/mdlayher/socket                                   from github.com/mdlayher/netlink
      💣 github.com/mitchellh/go-ps                                   from tailscale.com/cmd/tailscale/cli+
         github.com/peterbourgon/ff/v3                                from github.com/peterbourgon/ff/v3/ffcli
         github.com/peterbourgon/ff/v3/ffcli                          from tailscale.com/cmd/tailscale/cli
@@ -20,47 +30,50 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         github.com/tailscale/goupnp/ssdp                             from github.com/tailscale/goupnp
         github.com/tcnksm/go-httpstat                                from tailscale.com/net/netcheck
         github.com/toqueteos/webbrowser                              from tailscale.com/cmd/tailscale/cli
-     💣 go4.org/intern                                               from inet.af/netaddr
+        github.com/x448/float16                                      from github.com/fxamacker/cbor/v2
      💣 go4.org/mem                                                  from tailscale.com/derp+
-        go4.org/unsafe/assume-no-moving-gc                           from go4.org/intern
+        go4.org/netipx                                               from tailscale.com/wgengine/filter
    W 💣 golang.zx2c4.com/wireguard/windows/tunnel/winipcfg           from tailscale.com/net/interfaces+
-        inet.af/netaddr                                              from tailscale.com/cmd/tailscale/cli+
-   L    nhooyr.io/websocket                                          from tailscale.com/derp/derphttp+
-   L    nhooyr.io/websocket/internal/errd                            from nhooyr.io/websocket
-   L    nhooyr.io/websocket/internal/xsync                           from nhooyr.io/websocket
+        nhooyr.io/websocket                                          from tailscale.com/derp/derphttp+
+        nhooyr.io/websocket/internal/errd                            from nhooyr.io/websocket
+        nhooyr.io/websocket/internal/xsync                           from nhooyr.io/websocket
         tailscale.com                                                from tailscale.com/version
         tailscale.com/atomicfile                                     from tailscale.com/ipn+
         tailscale.com/client/tailscale                               from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/client/tailscale/apitype                       from tailscale.com/client/tailscale+
+        tailscale.com/client/tailscale/apitype                       from tailscale.com/cmd/tailscale/cli+
         tailscale.com/cmd/tailscale/cli                              from tailscale.com/cmd/tailscale
+        tailscale.com/control/controlbase                            from tailscale.com/control/controlhttp
+        tailscale.com/control/controlhttp                            from tailscale.com/cmd/tailscale/cli
         tailscale.com/control/controlknobs                           from tailscale.com/net/portmapper
         tailscale.com/derp                                           from tailscale.com/derp/derphttp
         tailscale.com/derp/derphttp                                  from tailscale.com/net/netcheck
-   L    tailscale.com/derp/wsconn                                    from tailscale.com/derp/derphttp
         tailscale.com/disco                                          from tailscale.com/derp
         tailscale.com/envknob                                        from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/hostinfo                                       from tailscale.com/net/interfaces
+        tailscale.com/hostinfo                                       from tailscale.com/net/interfaces+
         tailscale.com/ipn                                            from tailscale.com/cmd/tailscale/cli+
         tailscale.com/ipn/ipnstate                                   from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/kube                                           from tailscale.com/ipn
      💣 tailscale.com/metrics                                        from tailscale.com/derp
-        tailscale.com/net/dnscache                                   from tailscale.com/derp/derphttp
+        tailscale.com/net/dnscache                                   from tailscale.com/derp/derphttp+
+        tailscale.com/net/dnsfallback                                from tailscale.com/control/controlhttp
         tailscale.com/net/flowtrack                                  from tailscale.com/wgengine/filter+
      💣 tailscale.com/net/interfaces                                 from tailscale.com/cmd/tailscale/cli+
+        tailscale.com/net/netaddr                                    from tailscale.com/disco+
         tailscale.com/net/netcheck                                   from tailscale.com/cmd/tailscale/cli
         tailscale.com/net/neterror                                   from tailscale.com/net/netcheck+
         tailscale.com/net/netknob                                    from tailscale.com/net/netns
         tailscale.com/net/netns                                      from tailscale.com/derp/derphttp+
+        tailscale.com/net/netutil                                    from tailscale.com/client/tailscale+
         tailscale.com/net/packet                                     from tailscale.com/wgengine/filter
         tailscale.com/net/portmapper                                 from tailscale.com/net/netcheck+
         tailscale.com/net/stun                                       from tailscale.com/net/netcheck
-        tailscale.com/net/tlsdial                                    from tailscale.com/derp/derphttp
+        tailscale.com/net/tlsdial                                    from tailscale.com/derp/derphttp+
         tailscale.com/net/tsaddr                                     from tailscale.com/net/interfaces+
      💣 tailscale.com/net/tshttpproxy                                from tailscale.com/derp/derphttp+
-     💣 tailscale.com/paths                                          from tailscale.com/cmd/tailscale/cli+
+        tailscale.com/paths                                          from tailscale.com/cmd/tailscale/cli+
         tailscale.com/safesocket                                     from tailscale.com/cmd/tailscale/cli+
-     💣 tailscale.com/syncs                                          from tailscale.com/net/interfaces+
+        tailscale.com/syncs                                          from tailscale.com/net/interfaces+
         tailscale.com/tailcfg                                        from tailscale.com/cmd/tailscale/cli+
+        tailscale.com/tka                                            from tailscale.com/types/key
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
      💣 tailscale.com/tstime/mono                                    from tailscale.com/tstime/rate
         tailscale.com/tstime/rate                                    from tailscale.com/wgengine/filter
@@ -70,30 +83,38 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/types/key                                      from tailscale.com/derp+
         tailscale.com/types/logger                                   from tailscale.com/cmd/tailscale/cli+
         tailscale.com/types/netmap                                   from tailscale.com/ipn
+        tailscale.com/types/nettype                                  from tailscale.com/net/netcheck+
         tailscale.com/types/opt                                      from tailscale.com/net/netcheck+
         tailscale.com/types/pad32                                    from tailscale.com/derp
         tailscale.com/types/persist                                  from tailscale.com/ipn
         tailscale.com/types/preftype                                 from tailscale.com/cmd/tailscale/cli+
         tailscale.com/types/structs                                  from tailscale.com/ipn+
+        tailscale.com/types/views                                    from tailscale.com/tailcfg+
         tailscale.com/util/clientmetric                              from tailscale.com/net/netcheck+
+        tailscale.com/util/cloudenv                                  from tailscale.com/net/dnscache+
+   W    tailscale.com/util/cmpver                                    from tailscale.com/net/tshttpproxy
         tailscale.com/util/dnsname                                   from tailscale.com/cmd/tailscale/cli+
    W    tailscale.com/util/endian                                    from tailscale.com/net/netns
         tailscale.com/util/groupmember                               from tailscale.com/cmd/tailscale/cli
         tailscale.com/util/lineread                                  from tailscale.com/net/interfaces+
+        tailscale.com/util/singleflight                              from tailscale.com/net/dnscache
+   W 💣 tailscale.com/util/winutil                                   from tailscale.com/hostinfo+
         tailscale.com/version                                        from tailscale.com/cmd/tailscale/cli+
         tailscale.com/version/distro                                 from tailscale.com/cmd/tailscale/cli+
         tailscale.com/wgengine/filter                                from tailscale.com/types/netmap
-        golang.org/x/crypto/blake2b                                  from golang.org/x/crypto/nacl/box
+        golang.org/x/crypto/argon2                                   from tailscale.com/tka
+        golang.org/x/crypto/blake2b                                  from golang.org/x/crypto/nacl/box+
+        golang.org/x/crypto/blake2s                                  from tailscale.com/control/controlbase+
         golang.org/x/crypto/chacha20                                 from golang.org/x/crypto/chacha20poly1305
-        golang.org/x/crypto/chacha20poly1305                         from crypto/tls
+        golang.org/x/crypto/chacha20poly1305                         from crypto/tls+
         golang.org/x/crypto/cryptobyte                               from crypto/ecdsa+
         golang.org/x/crypto/cryptobyte/asn1                          from crypto/ecdsa+
         golang.org/x/crypto/curve25519                               from crypto/tls+
-        golang.org/x/crypto/hkdf                                     from crypto/tls
+        golang.org/x/crypto/hkdf                                     from crypto/tls+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
-        golang.org/x/crypto/poly1305                                 from golang.org/x/crypto/chacha20poly1305
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
+   L    golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
         golang.org/x/net/dns/dnsmessage                              from net+
         golang.org/x/net/http/httpguts                               from net/http+
         golang.org/x/net/http/httpproxy                              from net/http
@@ -102,7 +123,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         golang.org/x/net/proxy                                       from tailscale.com/net/netns
    D    golang.org/x/net/route                                       from net+
         golang.org/x/sync/errgroup                                   from tailscale.com/derp+
-        golang.org/x/sync/singleflight                               from tailscale.com/net/dnscache
         golang.org/x/sys/cpu                                         from golang.org/x/crypto/blake2b+
   LD    golang.org/x/sys/unix                                        from tailscale.com/net/netns+
    W    golang.org/x/sys/windows                                     from golang.org/x/sys/windows/registry+
@@ -142,6 +162,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         embed                                                        from tailscale.com/cmd/tailscale/cli+
         encoding                                                     from encoding/json+
         encoding/asn1                                                from crypto/x509+
+        encoding/base32                                              from tailscale.com/tka
         encoding/base64                                              from encoding/json+
         encoding/binary                                              from compress/gzip+
         encoding/hex                                                 from crypto/x509+
@@ -162,7 +183,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         image/color                                                  from github.com/skip2/go-qrcode+
         image/png                                                    from github.com/skip2/go-qrcode
         io                                                           from bufio+
-        io/fs                                                        from crypto/rand+
+        io/fs                                                        from crypto/x509+
         io/ioutil                                                    from golang.org/x/sys/cpu+
         log                                                          from expvar+
         math                                                         from compress/flate+
@@ -177,18 +198,19 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         net/http/cgi                                                 from tailscale.com/cmd/tailscale/cli
         net/http/httptrace                                           from github.com/tcnksm/go-httpstat+
         net/http/internal                                            from net/http
+        net/netip                                                    from net+
         net/textproto                                                from golang.org/x/net/http/httpguts+
         net/url                                                      from crypto/x509+
         os                                                           from crypto/rand+
         os/exec                                                      from github.com/toqueteos/webbrowser+
         os/signal                                                    from tailscale.com/cmd/tailscale/cli
-        os/user                                                      from tailscale.com/util/groupmember
+        os/user                                                      from tailscale.com/util/groupmember+
         path                                                         from html/template+
         path/filepath                                                from crypto/x509+
         reflect                                                      from crypto/x509+
         regexp                                                       from github.com/tailscale/goupnp/httpu+
         regexp/syntax                                                from regexp
-        runtime/debug                                                from golang.org/x/sync/singleflight
+        runtime/debug                                                from tailscale.com/util/singleflight+
         sort                                                         from compress/flate+
         strconv                                                      from compress/flate+
         strings                                                      from bufio+

cmd/tailscaled/childproc/childproc.go

@@ -0,0 +1,20 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package childproc allows other packages to register "tailscaled be-child"
+// child process hook code. This avoids duplicating build tags in the
+// tailscaled package. Instead, the code that needs to fork/exec the self
+// executable (when it's tailscaled) can instead register the code
+// they want to run.
+package childproc
+
+var Code = map[string]func([]string) error{}
+
+// Add registers code f to run as 'tailscaled be-child <typ> [args]'.
+func Add(typ string, f func(args []string) error) {
+	if _, dup := Code[typ]; dup {
+		panic("dup hook " + typ)
+	}
+	Code[typ] = f
+}

cmd/tailscaled/debug.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.18
+// +build go1.18
+
 package main
 
 import (
@@ -17,12 +20,12 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptrace"
+	"net/netip"
 	"net/url"
 	"os"
 	"strings"
 	"time"
 
-	"inet.af/netaddr"
 	"tailscale.com/derp/derphttp"
 	"tailscale.com/envknob"
 	"tailscale.com/ipn"
@@ -263,11 +266,11 @@ func debugPortmap(ctx context.Context) error {
 		return err
 	}
 
-	gatewayAndSelfIP := func() (gw, self netaddr.IP, ok bool) {
+	gatewayAndSelfIP := func() (gw, self netip.Addr, ok bool) {
 		if v := os.Getenv("TS_DEBUG_GW_SELF"); strings.Contains(v, "/") {
 			i := strings.Index(v, "/")
-			gw = netaddr.MustParseIP(v[:i])
-			self = netaddr.MustParseIP(v[i+1:])
+			gw = netip.MustParseAddr(v[:i])
+			self = netip.MustParseAddr(v[i+1:])
 			return gw, self, true
 		}
 		return linkMon.GatewayAndSelfIP()

cmd/tailscaled/depaware.txt

@@ -1,12 +1,14 @@
 tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/depaware)
 
+        filippo.io/edwards25519                                      from github.com/hdevalence/ed25519consensus
+        filippo.io/edwards25519/field                                from filippo.io/edwards25519
    W 💣 github.com/alexbrainman/sspi                                 from github.com/alexbrainman/sspi/internal/common+
    W    github.com/alexbrainman/sspi/internal/common                 from github.com/alexbrainman/sspi/negotiate
    W 💣 github.com/alexbrainman/sspi/negotiate                       from tailscale.com/net/tshttpproxy
-   L    github.com/anmitsu/go-shlex                                  from github.com/gliderlabs/ssh
+  LD    github.com/anmitsu/go-shlex                                  from tailscale.com/tempfork/gliderlabs/ssh
    L    github.com/aws/aws-sdk-go-v2                                 from github.com/aws/aws-sdk-go-v2/internal/ini
    L    github.com/aws/aws-sdk-go-v2/aws                             from github.com/aws/aws-sdk-go-v2/aws/middleware+
-   L    github.com/aws/aws-sdk-go-v2/aws/arn                         from tailscale.com/ipn/store/aws
+   L    github.com/aws/aws-sdk-go-v2/aws/arn                         from tailscale.com/ipn/store/awsstore
    L    github.com/aws/aws-sdk-go-v2/aws/middleware                  from github.com/aws/aws-sdk-go-v2/aws/retry+
    L    github.com/aws/aws-sdk-go-v2/aws/protocol/query              from github.com/aws/aws-sdk-go-v2/service/sts
    L    github.com/aws/aws-sdk-go-v2/aws/protocol/restjson           from github.com/aws/aws-sdk-go-v2/service/ssm+
@@ -16,7 +18,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    L    github.com/aws/aws-sdk-go-v2/aws/signer/internal/v4          from github.com/aws/aws-sdk-go-v2/aws/signer/v4
    L    github.com/aws/aws-sdk-go-v2/aws/signer/v4                   from github.com/aws/aws-sdk-go-v2/service/internal/presigned-url+
    L    github.com/aws/aws-sdk-go-v2/aws/transport/http              from github.com/aws/aws-sdk-go-v2/config+
-   L    github.com/aws/aws-sdk-go-v2/config                          from tailscale.com/ipn/store/aws
+   L    github.com/aws/aws-sdk-go-v2/config                          from tailscale.com/ipn/store/awsstore
    L    github.com/aws/aws-sdk-go-v2/credentials                     from github.com/aws/aws-sdk-go-v2/config
    L    github.com/aws/aws-sdk-go-v2/credentials/ec2rolecreds        from github.com/aws/aws-sdk-go-v2/config
    L    github.com/aws/aws-sdk-go-v2/credentials/endpointcreds       from github.com/aws/aws-sdk-go-v2/config
@@ -36,7 +38,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    L    github.com/aws/aws-sdk-go-v2/internal/sync/singleflight      from github.com/aws/aws-sdk-go-v2/aws
    L    github.com/aws/aws-sdk-go-v2/internal/timeconv               from github.com/aws/aws-sdk-go-v2/aws/retry
    L    github.com/aws/aws-sdk-go-v2/service/internal/presigned-url  from github.com/aws/aws-sdk-go-v2/service/sts
-   L    github.com/aws/aws-sdk-go-v2/service/ssm                     from tailscale.com/ipn/store/aws
+   L    github.com/aws/aws-sdk-go-v2/service/ssm                     from tailscale.com/ipn/store/awsstore
    L    github.com/aws/aws-sdk-go-v2/service/ssm/internal/endpoints  from github.com/aws/aws-sdk-go-v2/service/ssm
    L    github.com/aws/aws-sdk-go-v2/service/ssm/types               from github.com/aws/aws-sdk-go-v2/service/ssm+
    L    github.com/aws/aws-sdk-go-v2/service/sso                     from github.com/aws/aws-sdk-go-v2/config+
@@ -61,35 +63,46 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    L    github.com/aws/smithy-go/transport/http/internal/io          from github.com/aws/smithy-go/transport/http
    L    github.com/aws/smithy-go/waiter                              from github.com/aws/aws-sdk-go-v2/service/ssm
    L    github.com/coreos/go-iptables/iptables                       from tailscale.com/wgengine/router
-   L 💣 github.com/creack/pty                                        from tailscale.com/wgengine/netstack
-   L    github.com/gliderlabs/ssh                                    from tailscale.com/wgengine/netstack
+  LD 💣 github.com/creack/pty                                        from tailscale.com/ssh/tailssh
+        github.com/fxamacker/cbor/v2                                 from tailscale.com/tka
    W 💣 github.com/go-ole/go-ole                                     from github.com/go-ole/go-ole/oleutil+
    W 💣 github.com/go-ole/go-ole/oleutil                             from tailscale.com/wgengine/winnet
-   L 💣 github.com/godbus/dbus/v5                                    from tailscale.com/net/dns
+   L 💣 github.com/godbus/dbus/v5                                    from tailscale.com/net/dns+
         github.com/golang/groupcache/lru                             from tailscale.com/net/dnscache
         github.com/google/btree                                      from gvisor.dev/gvisor/pkg/tcpip/header+
+        github.com/hdevalence/ed25519consensus                       from tailscale.com/tka
    L    github.com/insomniacslk/dhcp/dhcpv4                          from tailscale.com/net/tstun
    L    github.com/insomniacslk/dhcp/iana                            from github.com/insomniacslk/dhcp/dhcpv4
    L    github.com/insomniacslk/dhcp/interfaces                      from github.com/insomniacslk/dhcp/dhcpv4
    L    github.com/insomniacslk/dhcp/rfc1035label                    from github.com/insomniacslk/dhcp/dhcpv4
    L    github.com/jmespath/go-jmespath                              from github.com/aws/aws-sdk-go-v2/service/ssm
    L    github.com/josharian/native                                  from github.com/mdlayher/netlink+
-   L 💣 github.com/jsimonetti/rtnetlink                              from tailscale.com/wgengine/monitor
+   L 💣 github.com/jsimonetti/rtnetlink                              from tailscale.com/net/interfaces+
    L    github.com/jsimonetti/rtnetlink/internal/unix                from github.com/jsimonetti/rtnetlink
         github.com/klauspost/compress                                from github.com/klauspost/compress/zstd
-   L    github.com/klauspost/compress/flate                          from nhooyr.io/websocket
+        github.com/klauspost/compress/flate                          from nhooyr.io/websocket
         github.com/klauspost/compress/fse                            from github.com/klauspost/compress/huff0
         github.com/klauspost/compress/huff0                          from github.com/klauspost/compress/zstd
+        github.com/klauspost/compress/internal/cpuinfo               from github.com/klauspost/compress/zstd
         github.com/klauspost/compress/internal/snapref               from github.com/klauspost/compress/zstd
         github.com/klauspost/compress/zstd                           from tailscale.com/smallzstd
         github.com/klauspost/compress/zstd/internal/xxhash           from github.com/klauspost/compress/zstd
+        github.com/kortschak/wol                                     from tailscale.com/ipn/ipnlocal
+  LD    github.com/kr/fs                                             from github.com/pkg/sftp
+   L    github.com/mdlayher/genetlink                                from tailscale.com/net/tstun
    L 💣 github.com/mdlayher/netlink                                  from github.com/jsimonetti/rtnetlink+
    L 💣 github.com/mdlayher/netlink/nlenc                            from github.com/jsimonetti/rtnetlink+
    L    github.com/mdlayher/sdnotify                                 from tailscale.com/util/systemd
    L 💣 github.com/mdlayher/socket                                   from github.com/mdlayher/netlink
      💣 github.com/mitchellh/go-ps                                   from tailscale.com/safesocket
    W    github.com/pkg/errors                                        from github.com/tailscale/certstore
+  LD    github.com/pkg/sftp                                          from tailscale.com/ssh/tailssh
+  LD    github.com/pkg/sftp/internal/encoding/ssh/filexfer           from github.com/pkg/sftp
    W 💣 github.com/tailscale/certstore                               from tailscale.com/control/controlclient
+  LD    github.com/tailscale/golang-x-crypto/chacha20                from github.com/tailscale/golang-x-crypto/ssh
+  LD 💣 github.com/tailscale/golang-x-crypto/internal/subtle         from github.com/tailscale/golang-x-crypto/chacha20
+  LD    github.com/tailscale/golang-x-crypto/ssh                     from tailscale.com/ipn/ipnlocal+
+  LD    github.com/tailscale/golang-x-crypto/ssh/internal/bcrypt_pbkdf from github.com/tailscale/golang-x-crypto/ssh
         github.com/tailscale/goupnp                                  from github.com/tailscale/goupnp/dcps/internetgateway2+
         github.com/tailscale/goupnp/dcps/internetgateway2            from tailscale.com/net/portmapper
         github.com/tailscale/goupnp/httpu                            from github.com/tailscale/goupnp+
@@ -98,14 +111,15 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         github.com/tailscale/goupnp/ssdp                             from github.com/tailscale/goupnp
    L 💣 github.com/tailscale/netlink                                 from tailscale.com/wgengine/router
         github.com/tcnksm/go-httpstat                                from tailscale.com/net/netcheck
+  LD    github.com/u-root/u-root/pkg/termios                         from tailscale.com/ssh/tailssh
    L    github.com/u-root/uio/rand                                   from github.com/insomniacslk/dhcp/dhcpv4
    L    github.com/u-root/uio/ubinary                                from github.com/u-root/uio/uio
    L    github.com/u-root/uio/uio                                    from github.com/insomniacslk/dhcp/dhcpv4+
    L 💣 github.com/vishvananda/netlink/nl                            from github.com/tailscale/netlink
    L    github.com/vishvananda/netns                                 from github.com/tailscale/netlink+
-     💣 go4.org/intern                                               from inet.af/netaddr
-     💣 go4.org/mem                                                  from tailscale.com/client/tailscale+
-        go4.org/unsafe/assume-no-moving-gc                           from go4.org/intern
+        github.com/x448/float16                                      from github.com/fxamacker/cbor/v2
+     💣 go4.org/mem                                                  from tailscale.com/control/controlbase+
+        go4.org/netipx                                               from tailscale.com/ipn/ipnlocal+
    W 💣 golang.zx2c4.com/wintun                                      from golang.zx2c4.com/wireguard/tun
      💣 golang.zx2c4.com/wireguard/conn                              from golang.zx2c4.com/wireguard/device+
    W 💣 golang.zx2c4.com/wireguard/conn/winrio                       from golang.zx2c4.com/wireguard/conn
@@ -119,21 +133,21 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
      💣 golang.zx2c4.com/wireguard/tun                               from golang.zx2c4.com/wireguard/device+
    W 💣 golang.zx2c4.com/wireguard/windows/tunnel/winipcfg           from tailscale.com/cmd/tailscaled+
         gvisor.dev/gvisor/pkg/atomicbitops                           from gvisor.dev/gvisor/pkg/tcpip+
-     💣 gvisor.dev/gvisor/pkg/buffer                                 from gvisor.dev/gvisor/pkg/tcpip/stack
+        gvisor.dev/gvisor/pkg/bits                                   from gvisor.dev/gvisor/pkg/bufferv2
+     💣 gvisor.dev/gvisor/pkg/bufferv2                               from gvisor.dev/gvisor/pkg/tcpip+
         gvisor.dev/gvisor/pkg/context                                from gvisor.dev/gvisor/pkg/refs+
      💣 gvisor.dev/gvisor/pkg/gohacks                                from gvisor.dev/gvisor/pkg/state/wire+
         gvisor.dev/gvisor/pkg/linewriter                             from gvisor.dev/gvisor/pkg/log
         gvisor.dev/gvisor/pkg/log                                    from gvisor.dev/gvisor/pkg/context+
         gvisor.dev/gvisor/pkg/rand                                   from gvisor.dev/gvisor/pkg/tcpip/network/hash+
-        gvisor.dev/gvisor/pkg/refs                                   from gvisor.dev/gvisor/pkg/refsvfs2
-        gvisor.dev/gvisor/pkg/refsvfs2                               from gvisor.dev/gvisor/pkg/tcpip/stack
+        gvisor.dev/gvisor/pkg/refs                                   from gvisor.dev/gvisor/pkg/refsvfs2+
+        gvisor.dev/gvisor/pkg/refsvfs2                               from gvisor.dev/gvisor/pkg/tcpip/stack+
      💣 gvisor.dev/gvisor/pkg/sleep                                  from gvisor.dev/gvisor/pkg/tcpip/transport/tcp
      💣 gvisor.dev/gvisor/pkg/state                                  from gvisor.dev/gvisor/pkg/atomicbitops+
         gvisor.dev/gvisor/pkg/state/wire                             from gvisor.dev/gvisor/pkg/state
      💣 gvisor.dev/gvisor/pkg/sync                                   from gvisor.dev/gvisor/pkg/linewriter+
-        gvisor.dev/gvisor/pkg/tcpip                                  from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
+        gvisor.dev/gvisor/pkg/tcpip                                  from gvisor.dev/gvisor/pkg/tcpip/header+
         gvisor.dev/gvisor/pkg/tcpip/adapters/gonet                   from tailscale.com/wgengine/netstack
-     💣 gvisor.dev/gvisor/pkg/tcpip/buffer                           from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
         gvisor.dev/gvisor/pkg/tcpip/hash/jenkins                     from gvisor.dev/gvisor/pkg/tcpip/stack+
         gvisor.dev/gvisor/pkg/tcpip/header                           from gvisor.dev/gvisor/pkg/tcpip/header/parse+
         gvisor.dev/gvisor/pkg/tcpip/header/parse                     from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
@@ -142,83 +156,95 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         gvisor.dev/gvisor/pkg/tcpip/network/hash                     from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
         gvisor.dev/gvisor/pkg/tcpip/network/internal/fragmentation   from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
         gvisor.dev/gvisor/pkg/tcpip/network/internal/ip              from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
+        gvisor.dev/gvisor/pkg/tcpip/network/internal/multicast       from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
         gvisor.dev/gvisor/pkg/tcpip/network/ipv4                     from tailscale.com/net/tstun+
         gvisor.dev/gvisor/pkg/tcpip/network/ipv6                     from tailscale.com/wgengine/netstack
         gvisor.dev/gvisor/pkg/tcpip/ports                            from gvisor.dev/gvisor/pkg/tcpip/stack+
         gvisor.dev/gvisor/pkg/tcpip/seqnum                           from gvisor.dev/gvisor/pkg/tcpip/header+
-     💣 gvisor.dev/gvisor/pkg/tcpip/stack                            from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
-        gvisor.dev/gvisor/pkg/tcpip/transport                        from gvisor.dev/gvisor/pkg/tcpip/transport/icmp+
+     💣 gvisor.dev/gvisor/pkg/tcpip/stack                            from gvisor.dev/gvisor/pkg/tcpip/header/parse+
+        gvisor.dev/gvisor/pkg/tcpip/transport                        from gvisor.dev/gvisor/pkg/tcpip/transport/internal/network+
         gvisor.dev/gvisor/pkg/tcpip/transport/icmp                   from tailscale.com/wgengine/netstack
-        gvisor.dev/gvisor/pkg/tcpip/transport/internal/network       from gvisor.dev/gvisor/pkg/tcpip/transport/icmp+
+        gvisor.dev/gvisor/pkg/tcpip/transport/internal/network       from gvisor.dev/gvisor/pkg/tcpip/transport/raw+
         gvisor.dev/gvisor/pkg/tcpip/transport/internal/noop          from gvisor.dev/gvisor/pkg/tcpip/transport/raw
         gvisor.dev/gvisor/pkg/tcpip/transport/packet                 from gvisor.dev/gvisor/pkg/tcpip/transport/raw
-        gvisor.dev/gvisor/pkg/tcpip/transport/raw                    from gvisor.dev/gvisor/pkg/tcpip/transport/icmp+
+        gvisor.dev/gvisor/pkg/tcpip/transport/raw                    from gvisor.dev/gvisor/pkg/tcpip/transport/udp+
      💣 gvisor.dev/gvisor/pkg/tcpip/transport/tcp                    from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
         gvisor.dev/gvisor/pkg/tcpip/transport/tcpconntrack           from gvisor.dev/gvisor/pkg/tcpip/stack
-        gvisor.dev/gvisor/pkg/tcpip/transport/udp                    from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
+        gvisor.dev/gvisor/pkg/tcpip/transport/udp                    from tailscale.com/net/tstun+
         gvisor.dev/gvisor/pkg/waiter                                 from gvisor.dev/gvisor/pkg/context+
-        inet.af/netaddr                                              from inet.af/wf+
         inet.af/peercred                                             from tailscale.com/ipn/ipnserver
    W 💣 inet.af/wf                                                   from tailscale.com/wf
-   L    nhooyr.io/websocket                                          from tailscale.com/derp/derphttp+
-   L    nhooyr.io/websocket/internal/errd                            from nhooyr.io/websocket
-   L    nhooyr.io/websocket/internal/xsync                           from nhooyr.io/websocket
+        nhooyr.io/websocket                                          from tailscale.com/derp/derphttp+
+        nhooyr.io/websocket/internal/errd                            from nhooyr.io/websocket
+        nhooyr.io/websocket/internal/xsync                           from nhooyr.io/websocket
         tailscale.com                                                from tailscale.com/version
         tailscale.com/atomicfile                                     from tailscale.com/ipn+
   LD    tailscale.com/chirp                                          from tailscale.com/cmd/tailscaled
         tailscale.com/client/tailscale                               from tailscale.com/derp
-        tailscale.com/client/tailscale/apitype                       from tailscale.com/client/tailscale+
+        tailscale.com/client/tailscale/apitype                       from tailscale.com/ipn/ipnlocal+
+        tailscale.com/cmd/tailscaled/childproc                       from tailscale.com/ssh/tailssh+
+        tailscale.com/control/controlbase                            from tailscale.com/control/controlclient+
         tailscale.com/control/controlclient                          from tailscale.com/ipn/ipnlocal+
+        tailscale.com/control/controlhttp                            from tailscale.com/control/controlclient
         tailscale.com/control/controlknobs                           from tailscale.com/control/controlclient+
         tailscale.com/derp                                           from tailscale.com/derp/derphttp+
-        tailscale.com/derp/derphttp                                  from tailscale.com/cmd/tailscaled+
-   L    tailscale.com/derp/wsconn                                    from tailscale.com/derp/derphttp
+        tailscale.com/derp/derphttp                                  from tailscale.com/net/netcheck+
         tailscale.com/disco                                          from tailscale.com/derp+
-        tailscale.com/envknob                                        from tailscale.com/cmd/tailscaled+
+        tailscale.com/envknob                                        from tailscale.com/control/controlclient+
         tailscale.com/health                                         from tailscale.com/control/controlclient+
         tailscale.com/hostinfo                                       from tailscale.com/control/controlclient+
-        tailscale.com/ipn                                            from tailscale.com/client/tailscale+
-        tailscale.com/ipn/ipnlocal                                   from tailscale.com/ipn/ipnserver+
+        tailscale.com/ipn                                            from tailscale.com/ipn/ipnlocal+
+        tailscale.com/ipn/ipnlocal                                   from tailscale.com/ssh/tailssh+
         tailscale.com/ipn/ipnserver                                  from tailscale.com/cmd/tailscaled
-        tailscale.com/ipn/ipnstate                                   from tailscale.com/client/tailscale+
+        tailscale.com/ipn/ipnstate                                   from tailscale.com/control/controlclient+
         tailscale.com/ipn/localapi                                   from tailscale.com/ipn/ipnserver
         tailscale.com/ipn/policy                                     from tailscale.com/ipn/ipnlocal
-        tailscale.com/ipn/store/aws                                  from tailscale.com/ipn/ipnserver
-        tailscale.com/kube                                           from tailscale.com/ipn
+        tailscale.com/ipn/store                                      from tailscale.com/cmd/tailscaled
+   L    tailscale.com/ipn/store/awsstore                             from tailscale.com/ipn/store
+   L    tailscale.com/ipn/store/kubestore                            from tailscale.com/ipn/store
+        tailscale.com/ipn/store/mem                                  from tailscale.com/ipn/store+
+   L    tailscale.com/kube                                           from tailscale.com/ipn/store/kubestore
         tailscale.com/log/filelogger                                 from tailscale.com/logpolicy
         tailscale.com/log/logheap                                    from tailscale.com/control/controlclient
         tailscale.com/logpolicy                                      from tailscale.com/cmd/tailscaled+
-        tailscale.com/logtail                                        from tailscale.com/logpolicy+
-        tailscale.com/logtail/backoff                                from tailscale.com/cmd/tailscaled+
+        tailscale.com/logtail                                        from tailscale.com/control/controlclient+
+        tailscale.com/logtail/backoff                                from tailscale.com/control/controlclient+
         tailscale.com/logtail/filch                                  from tailscale.com/logpolicy
      💣 tailscale.com/metrics                                        from tailscale.com/derp+
-        tailscale.com/net/dns                                        from tailscale.com/cmd/tailscaled+
-        tailscale.com/net/dns/resolver                               from tailscale.com/net/dns+
+        tailscale.com/net/dns                                        from tailscale.com/ipn/ipnlocal+
+        tailscale.com/net/dns/publicdns                              from tailscale.com/net/dns/resolver
+        tailscale.com/net/dns/resolvconffile                         from tailscale.com/net/dns+
+        tailscale.com/net/dns/resolver                               from tailscale.com/ipn/ipnlocal+
         tailscale.com/net/dnscache                                   from tailscale.com/control/controlclient+
         tailscale.com/net/dnsfallback                                from tailscale.com/control/controlclient+
         tailscale.com/net/flowtrack                                  from tailscale.com/net/packet+
-     💣 tailscale.com/net/interfaces                                 from tailscale.com/cmd/tailscaled+
+     💣 tailscale.com/net/interfaces                                 from tailscale.com/control/controlclient+
+        tailscale.com/net/netaddr                                    from tailscale.com/disco+
         tailscale.com/net/netcheck                                   from tailscale.com/wgengine/magicsock
-        tailscale.com/net/neterror                                   from tailscale.com/net/netcheck+
-        tailscale.com/net/netknob                                    from tailscale.com/logpolicy+
-        tailscale.com/net/netns                                      from tailscale.com/cmd/tailscaled+
+        tailscale.com/net/neterror                                   from tailscale.com/net/dns/resolver+
+        tailscale.com/net/netknob                                    from tailscale.com/net/netns+
+        tailscale.com/net/netns                                      from tailscale.com/derp/derphttp+
      💣 tailscale.com/net/netstat                                    from tailscale.com/ipn/ipnserver
+        tailscale.com/net/netutil                                    from tailscale.com/ipn/ipnlocal+
         tailscale.com/net/packet                                     from tailscale.com/net/tstun+
-        tailscale.com/net/portmapper                                 from tailscale.com/cmd/tailscaled+
+        tailscale.com/net/portmapper                                 from tailscale.com/net/netcheck+
         tailscale.com/net/proxymux                                   from tailscale.com/cmd/tailscaled
         tailscale.com/net/socks5                                     from tailscale.com/cmd/tailscaled
         tailscale.com/net/stun                                       from tailscale.com/net/netcheck+
         tailscale.com/net/tlsdial                                    from tailscale.com/control/controlclient+
-        tailscale.com/net/tsaddr                                     from tailscale.com/ipn/ipnlocal+
-        tailscale.com/net/tsdial                                     from tailscale.com/cmd/tailscaled+
-     💣 tailscale.com/net/tshttpproxy                                from tailscale.com/cmd/tailscaled+
-        tailscale.com/net/tstun                                      from tailscale.com/cmd/tailscaled+
-     💣 tailscale.com/paths                                          from tailscale.com/client/tailscale+
+        tailscale.com/net/tsaddr                                     from tailscale.com/ipn+
+        tailscale.com/net/tsdial                                     from tailscale.com/control/controlclient+
+     💣 tailscale.com/net/tshttpproxy                                from tailscale.com/control/controlclient+
+        tailscale.com/net/tstun                                      from tailscale.com/net/dns+
+        tailscale.com/paths                                          from tailscale.com/ipn/ipnlocal+
         tailscale.com/portlist                                       from tailscale.com/ipn/ipnlocal
         tailscale.com/safesocket                                     from tailscale.com/client/tailscale+
         tailscale.com/smallzstd                                      from tailscale.com/ipn/ipnserver+
-     💣 tailscale.com/syncs                                          from tailscale.com/control/controlknobs+
-        tailscale.com/tailcfg                                        from tailscale.com/client/tailscale+
+  LD 💣 tailscale.com/ssh/tailssh                                    from tailscale.com/cmd/tailscaled
+        tailscale.com/syncs                                          from tailscale.com/control/controlknobs+
+        tailscale.com/tailcfg                                        from tailscale.com/client/tailscale/apitype+
+  LD    tailscale.com/tempfork/gliderlabs/ssh                        from tailscale.com/ssh/tailssh
+        tailscale.com/tka                                            from tailscale.com/types/key
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
         tailscale.com/tstime                                         from tailscale.com/wgengine/magicsock
      💣 tailscale.com/tstime/mono                                    from tailscale.com/net/tstun+
@@ -228,78 +254,82 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/types/empty                                    from tailscale.com/control/controlclient+
         tailscale.com/types/flagtype                                 from tailscale.com/cmd/tailscaled
         tailscale.com/types/ipproto                                  from tailscale.com/net/flowtrack+
-        tailscale.com/types/key                                      from tailscale.com/cmd/tailscaled+
-        tailscale.com/types/logger                                   from tailscale.com/cmd/tailscaled+
+        tailscale.com/types/key                                      from tailscale.com/control/controlbase+
+        tailscale.com/types/logger                                   from tailscale.com/control/controlclient+
         tailscale.com/types/netmap                                   from tailscale.com/control/controlclient+
-        tailscale.com/types/nettype                                  from tailscale.com/wgengine/magicsock
+        tailscale.com/types/nettype                                  from tailscale.com/wgengine/magicsock+
         tailscale.com/types/opt                                      from tailscale.com/control/controlclient+
         tailscale.com/types/pad32                                    from tailscale.com/derp
         tailscale.com/types/persist                                  from tailscale.com/control/controlclient+
         tailscale.com/types/preftype                                 from tailscale.com/ipn+
         tailscale.com/types/structs                                  from tailscale.com/control/controlclient+
-        tailscale.com/util/clientmetric                              from tailscale.com/ipn/localapi+
-   L    tailscale.com/util/cmpver                                    from tailscale.com/net/dns
+        tailscale.com/types/views                                    from tailscale.com/ipn/ipnlocal+
+        tailscale.com/util/clientmetric                              from tailscale.com/control/controlclient+
+        tailscale.com/util/cloudenv                                  from tailscale.com/net/dns/resolver+
+  LW    tailscale.com/util/cmpver                                    from tailscale.com/net/dns+
      💣 tailscale.com/util/deephash                                  from tailscale.com/ipn/ipnlocal+
         tailscale.com/util/dnsname                                   from tailscale.com/hostinfo+
   LW    tailscale.com/util/endian                                    from tailscale.com/net/dns+
         tailscale.com/util/groupmember                               from tailscale.com/ipn/ipnserver
         tailscale.com/util/lineread                                  from tailscale.com/hostinfo+
-        tailscale.com/util/multierr                                  from tailscale.com/cmd/tailscaled+
-        tailscale.com/util/osshare                                   from tailscale.com/cmd/tailscaled+
+        tailscale.com/util/mak                                       from tailscale.com/control/controlclient+
+        tailscale.com/util/multierr                                  from tailscale.com/control/controlclient+
+        tailscale.com/util/osshare                                   from tailscale.com/ipn/ipnlocal+
         tailscale.com/util/pidowner                                  from tailscale.com/ipn/ipnserver
         tailscale.com/util/racebuild                                 from tailscale.com/logpolicy
+        tailscale.com/util/singleflight                              from tailscale.com/control/controlclient+
         tailscale.com/util/systemd                                   from tailscale.com/control/controlclient+
         tailscale.com/util/uniq                                      from tailscale.com/wgengine/magicsock
-        tailscale.com/util/winutil                                   from tailscale.com/cmd/tailscaled+
-   W 💣 tailscale.com/util/winutil/vss                               from tailscale.com/util/winutil
-        tailscale.com/version                                        from tailscale.com/client/tailscale+
-        tailscale.com/version/distro                                 from tailscale.com/cmd/tailscaled+
+     💣 tailscale.com/util/winutil                                   from tailscale.com/cmd/tailscaled+
+        tailscale.com/version                                        from tailscale.com/derp+
+        tailscale.com/version/distro                                 from tailscale.com/hostinfo+
    W    tailscale.com/wf                                             from tailscale.com/cmd/tailscaled
-        tailscale.com/wgengine                                       from tailscale.com/cmd/tailscaled+
+        tailscale.com/wgengine                                       from tailscale.com/ipn/ipnlocal+
         tailscale.com/wgengine/filter                                from tailscale.com/control/controlclient+
-        tailscale.com/wgengine/magicsock                             from tailscale.com/wgengine+
-        tailscale.com/wgengine/monitor                               from tailscale.com/cmd/tailscaled+
-     💣 tailscale.com/wgengine/netstack                              from tailscale.com/cmd/tailscaled
-        tailscale.com/wgengine/router                                from tailscale.com/cmd/tailscaled+
+        tailscale.com/wgengine/magicsock                             from tailscale.com/ipn/ipnlocal+
+        tailscale.com/wgengine/monitor                               from tailscale.com/control/controlclient+
+        tailscale.com/wgengine/netstack                              from tailscale.com/cmd/tailscaled+
+        tailscale.com/wgengine/router                                from tailscale.com/ipn/ipnlocal+
         tailscale.com/wgengine/wgcfg                                 from tailscale.com/ipn/ipnlocal+
         tailscale.com/wgengine/wgcfg/nmcfg                           from tailscale.com/ipn/ipnlocal
         tailscale.com/wgengine/wglog                                 from tailscale.com/wgengine
    W 💣 tailscale.com/wgengine/winnet                                from tailscale.com/wgengine/router
         golang.org/x/crypto/acme                                     from tailscale.com/ipn/localapi
-        golang.org/x/crypto/blake2b                                  from golang.org/x/crypto/nacl/box
-        golang.org/x/crypto/blake2s                                  from golang.zx2c4.com/wireguard/device
-   L    golang.org/x/crypto/blowfish                                 from golang.org/x/crypto/ssh/internal/bcrypt_pbkdf
+        golang.org/x/crypto/argon2                                   from tailscale.com/tka
+        golang.org/x/crypto/blake2b                                  from golang.org/x/crypto/nacl/box+
+        golang.org/x/crypto/blake2s                                  from golang.zx2c4.com/wireguard/device+
+  LD    golang.org/x/crypto/blowfish                                 from golang.org/x/crypto/ssh/internal/bcrypt_pbkdf+
         golang.org/x/crypto/chacha20                                 from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/chacha20poly1305                         from crypto/tls+
         golang.org/x/crypto/cryptobyte                               from crypto/ecdsa+
         golang.org/x/crypto/cryptobyte/asn1                          from crypto/ecdsa+
         golang.org/x/crypto/curve25519                               from crypto/tls+
-   L    golang.org/x/crypto/ed25519                                  from golang.org/x/crypto/ssh
-        golang.org/x/crypto/hkdf                                     from crypto/tls
+  LD    golang.org/x/crypto/ed25519                                  from golang.org/x/crypto/ssh+
+        golang.org/x/crypto/hkdf                                     from crypto/tls+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
-        golang.org/x/crypto/poly1305                                 from golang.org/x/crypto/chacha20poly1305+
+        golang.org/x/crypto/poly1305                                 from golang.zx2c4.com/wireguard/device+
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
-   L    golang.org/x/crypto/ssh                                      from github.com/gliderlabs/ssh+
-        golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
+  LD    golang.org/x/crypto/ssh                                      from tailscale.com/ssh/tailssh+
+        golang.org/x/net/bpf                                         from github.com/mdlayher/genetlink+
         golang.org/x/net/dns/dnsmessage                              from net+
-        golang.org/x/net/http/httpguts                               from net/http+
+        golang.org/x/net/http/httpguts                               from golang.org/x/net/http2+
         golang.org/x/net/http/httpproxy                              from net/http
         golang.org/x/net/http2                                       from golang.org/x/net/http2/h2c+
         golang.org/x/net/http2/h2c                                   from tailscale.com/ipn/ipnlocal
-        golang.org/x/net/http2/hpack                                 from net/http+
+        golang.org/x/net/http2/hpack                                 from golang.org/x/net/http2+
         golang.org/x/net/idna                                        from golang.org/x/net/http/httpguts+
         golang.org/x/net/ipv4                                        from golang.zx2c4.com/wireguard/device
         golang.org/x/net/ipv6                                        from golang.zx2c4.com/wireguard/device+
         golang.org/x/net/proxy                                       from tailscale.com/net/netns
    D    golang.org/x/net/route                                       from net+
-        golang.org/x/sync/errgroup                                   from github.com/tailscale/goupnp/httpu+
-        golang.org/x/sync/singleflight                               from tailscale.com/net/dnscache
+        golang.org/x/sync/errgroup                                   from github.com/mdlayher/socket+
         golang.org/x/sys/cpu                                         from golang.org/x/crypto/blake2b+
   LD    golang.org/x/sys/unix                                        from github.com/insomniacslk/dhcp/interfaces+
    W    golang.org/x/sys/windows                                     from github.com/go-ole/go-ole+
-   W    golang.org/x/sys/windows/registry                            from golang.zx2c4.com/wireguard/windows/tunnel/winipcfg+
+   W    golang.org/x/sys/windows/registry                            from golang.org/x/sys/windows/svc/eventlog+
    W    golang.org/x/sys/windows/svc                                 from golang.org/x/sys/windows/svc/mgr+
+   W    golang.org/x/sys/windows/svc/eventlog                        from tailscale.com/cmd/tailscaled
    W    golang.org/x/sys/windows/svc/mgr                             from tailscale.com/cmd/tailscaled
         golang.org/x/term                                            from tailscale.com/logpolicy
         golang.org/x/text/secure/bidirule                            from golang.org/x/net/idna
@@ -310,7 +340,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         bufio                                                        from compress/flate+
         bytes                                                        from bufio+
         compress/flate                                               from compress/gzip+
-        compress/gzip                                                from internal/profile+
+        compress/gzip                                                from golang.org/x/net/http2+
         container/heap                                               from gvisor.dev/gvisor/pkg/tcpip/transport/tcp
         container/list                                               from crypto/tls+
         context                                                      from crypto/tls+
@@ -331,31 +361,33 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         crypto/sha256                                                from crypto/tls+
         crypto/sha512                                                from crypto/ecdsa+
         crypto/subtle                                                from crypto/aes+
-        crypto/tls                                                   from github.com/aws/aws-sdk-go-v2/aws/transport/http+
+        crypto/tls                                                   from github.com/tcnksm/go-httpstat+
         crypto/x509                                                  from crypto/tls+
         crypto/x509/pkix                                             from crypto/x509+
-        embed                                                        from tailscale.com/net/dns+
+        embed                                                        from tailscale.com+
         encoding                                                     from encoding/json+
         encoding/asn1                                                from crypto/x509+
+        encoding/base32                                              from tailscale.com/tka
         encoding/base64                                              from encoding/json+
         encoding/binary                                              from compress/gzip+
         encoding/hex                                                 from crypto/x509+
         encoding/json                                                from expvar+
         encoding/pem                                                 from crypto/tls+
-        encoding/xml                                                 from github.com/aws/aws-sdk-go-v2/aws/protocol/xml+
+        encoding/xml                                                 from github.com/tailscale/goupnp+
         errors                                                       from bufio+
         expvar                                                       from tailscale.com/derp+
-        flag                                                         from tailscale.com/cmd/tailscaled+
+        flag                                                         from tailscale.com/control/controlclient+
         fmt                                                          from compress/flate+
         hash                                                         from crypto+
         hash/crc32                                                   from compress/gzip+
-        hash/fnv                                                     from gvisor.dev/gvisor/pkg/tcpip/network/ipv6+
+        hash/fnv                                                     from tailscale.com/wgengine/magicsock+
         hash/maphash                                                 from go4.org/mem
-        html                                                         from net/http/pprof+
+        html                                                         from tailscale.com/ipn/ipnlocal+
         io                                                           from bufio+
-        io/fs                                                        from crypto/rand+
-        io/ioutil                                                    from github.com/aws/aws-sdk-go-v2/aws/protocol/query+
+        io/fs                                                        from crypto/x509+
+        io/ioutil                                                    from github.com/godbus/dbus/v5+
         log                                                          from expvar+
+  LD    log/syslog                                                   from tailscale.com/ssh/tailssh
         math                                                         from compress/flate+
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+
@@ -369,19 +401,20 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         net/http/httputil                                            from github.com/aws/smithy-go/transport/http+
         net/http/internal                                            from net/http+
         net/http/pprof                                               from tailscale.com/cmd/tailscaled+
-        net/textproto                                                from github.com/aws/aws-sdk-go-v2/aws/signer/v4+
+        net/netip                                                    from golang.zx2c4.com/wireguard/conn+
+        net/textproto                                                from golang.org/x/net/http/httpguts+
         net/url                                                      from crypto/x509+
         os                                                           from crypto/rand+
-        os/exec                                                      from github.com/aws/aws-sdk-go-v2/credentials/processcreds+
+        os/exec                                                      from github.com/coreos/go-iptables/iptables+
         os/signal                                                    from tailscale.com/cmd/tailscaled+
         os/user                                                      from github.com/godbus/dbus/v5+
-        path                                                         from github.com/aws/aws-sdk-go-v2/credentials/ec2rolecreds+
+        path                                                         from github.com/godbus/dbus/v5+
         path/filepath                                                from crypto/x509+
         reflect                                                      from crypto/x509+
-        regexp                                                       from github.com/aws/aws-sdk-go-v2/internal/endpoints/v2+
+        regexp                                                       from github.com/coreos/go-iptables/iptables+
         regexp/syntax                                                from regexp
         runtime/debug                                                from github.com/klauspost/compress/zstd+
-        runtime/pprof                                                from net/http/pprof+
+        runtime/pprof                                                from tailscale.com/log/logheap+
         runtime/trace                                                from net/http/pprof
         sort                                                         from compress/flate+
         strconv                                                      from compress/flate+

cmd/tailscaled/install_darwin.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.18
+// +build go1.18
+
 package main
 
 import (

cmd/tailscaled/install_windows.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.18
+// +build go1.18
+
 package main
 
 import (

cmd/tailscaled/proxy.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.18
+// +build go1.18
+
 // HTTP proxy code
 
 package main

cmd/tailscaled/required_version.go

@@ -0,0 +1,12 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.18
+// +build !go1.18
+
+package main
+
+func init() {
+	you_need_Go_1_18_to_compile_Tailscale()
+}

cmd/tailscaled/ssh.go

@@ -0,0 +1,11 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux || darwin
+// +build linux darwin
+
+package main
+
+// Force registration of tailssh with LocalBackend.
+import _ "tailscale.com/ssh/tailssh"

cmd/tailscaled/tailscaled.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.18
+// +build go1.18
+
 // The tailscaled program is the Tailscale client daemon. It's configured
 // and controlled via the tailscale CLI program.
 //
@@ -18,19 +21,21 @@ import (
 	"net"
 	"net/http"
 	"net/http/pprof"
+	"net/netip"
 	"os"
 	"os/signal"
 	"path/filepath"
 	"runtime"
-	"runtime/debug"
 	"strings"
 	"syscall"
 	"time"
 
-	"inet.af/netaddr"
+	"tailscale.com/cmd/tailscaled/childproc"
+	"tailscale.com/control/controlclient"
 	"tailscale.com/envknob"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnserver"
+	"tailscale.com/ipn/store"
 	"tailscale.com/logpolicy"
 	"tailscale.com/logtail"
 	"tailscale.com/net/dns"
@@ -67,11 +72,27 @@ func defaultTunName() string {
 		// as a magic value that uses/creates any free number.
 		return "utun"
 	case "linux":
-		if distro.Get() == distro.Synology {
+		switch distro.Get() {
+		case distro.Synology:
 			// Try TUN, but fall back to userspace networking if needed.
 			// See https://github.com/tailscale/tailscale-synology/issues/35
 			return "tailscale0,userspace-networking"
+		case distro.Gokrazy:
+			// Gokrazy doesn't yet work in tun mode because the whole
+			// Gokrazy thing is no C code, and Tailscale currently
+			// depends on the iptables binary for Linux's
+			// wgengine/router.
+			// But on Gokrazy there's no legacy iptables, so we could use netlink
+			// to program nft-iptables directly. It just isn't done yet;
+			// see https://github.com/tailscale/tailscale/issues/391
+			//
+			// But Gokrazy does have the tun module built-in, so users
+			// can stil run --tun=tailscale0 if they wish, if they
+			// arrange for iptables to be present or run in "tailscale
+			// up --netfilter-mode=off" mode, perhaps. Untested.
+			return "userspace-networking"
 		}
+
 	}
 	return "tailscale0"
 }
@@ -104,17 +125,12 @@ var subCommands = map[string]*func([]string) error{
 	"install-system-daemon":   &installSystemDaemon,
 	"uninstall-system-daemon": &uninstallSystemDaemon,
 	"debug":                   &debugModeFunc,
+	"be-child":                &beChildFunc,
 }
 
-func main() {
-	// We aren't very performance sensitive, and the parts that are
-	// performance sensitive (wireguard) try hard not to do any memory
-	// allocations. So let's be aggressive about garbage collection,
-	// unless the user specifically overrides it in the usual way.
-	if _, ok := os.LookupEnv("GOGC"); !ok {
-		debug.SetGCPercent(10)
-	}
+var beCLI func() // non-nil if CLI is linked in
 
+func main() {
 	printVersion := false
 	flag.IntVar(&args.verbose, "verbose", 0, "log verbosity level; 0 is default, 1 or higher are increasingly verbose")
 	flag.BoolVar(&args.cleanup, "cleanup", false, "clean up system state and exit")
@@ -123,12 +139,17 @@ func main() {
 	flag.StringVar(&args.httpProxyAddr, "outbound-http-proxy-listen", "", `optional [ip]:port to run an outbound HTTP proxy (e.g. "localhost:8080")`)
 	flag.StringVar(&args.tunname, "tun", defaultTunName(), `tunnel interface name; use "userspace-networking" (beta) to not use TUN`)
 	flag.Var(flagtype.PortValue(&args.port, 0), "port", "UDP port to listen on for WireGuard and peer-to-peer traffic; 0 means automatically select")
-	flag.StringVar(&args.statepath, "state", paths.DefaultTailscaledStateFile(), "absolute path of state file; use 'kube:<secret-name>' to use Kubernetes secrets or 'arn:aws:ssm:...' to store in AWS SSM. If empty and --statedir is provided, the default is <statedir>/tailscaled.state")
+	flag.StringVar(&args.statepath, "state", "", "absolute path of state file; use 'kube:<secret-name>' to use Kubernetes secrets or 'arn:aws:ssm:...' to store in AWS SSM; use 'mem:' to not store state and register as an emphemeral node. If empty and --statedir is provided, the default is <statedir>/tailscaled.state. Default: "+paths.DefaultTailscaledStateFile())
 	flag.StringVar(&args.statedir, "statedir", "", "path to directory for storage of config state, TLS certs, temporary incoming Taildrop files, etc. If empty, it's derived from --state when possible.")
 	flag.StringVar(&args.socketpath, "socket", paths.DefaultTailscaledSocket(), "path of the service unix socket")
 	flag.StringVar(&args.birdSocketPath, "bird-socket", "", "path of the bird unix socket")
 	flag.BoolVar(&printVersion, "version", false, "print version information and exit")
 
+	if len(os.Args) > 0 && filepath.Base(os.Args[0]) == "tailscale" && beCLI != nil {
+		beCLI()
+		return
+	}
+
 	if len(os.Args) > 1 {
 		sub := os.Args[1]
 		if fp, ok := subCommands[sub]; ok {
@@ -144,13 +165,12 @@ func main() {
 		}
 	}
 
-	if beWindowsSubprocess() {
-		return
-	}
-
 	flag.Parse()
 	if flag.NArg() > 0 {
-		log.Fatalf("tailscaled does not take non-flag arguments: %q", flag.Args())
+		// Windows subprocess is spawned with /subprocess, so we need to avoid this check there.
+		if runtime.GOOS != "windows" || (flag.Arg(0) != "/subproc" && flag.Arg(0) != "/firewall") {
+			log.Fatalf("tailscaled does not take non-flag arguments: %q", flag.Args())
+		}
 	}
 
 	if printVersion {
@@ -173,6 +193,16 @@ func main() {
 		log.Fatalf("--bird-socket is not supported on %s", runtime.GOOS)
 	}
 
+	// Only apply a default statepath when neither have been provided, so that a
+	// user may specify only --statedir if they wish.
+	if args.statepath == "" && args.statedir == "" {
+		args.statepath = paths.DefaultTailscaledStateFile()
+	}
+
+	if beWindowsSubprocess() {
+		return
+	}
+
 	err := run()
 
 	// Remove file sharing from Windows shell (noop in non-windows)
@@ -238,6 +268,10 @@ func ipnServerOpts() (o ipnserver.Options) {
 			o.VarRoot = dir
 		}
 	}
+	if strings.HasPrefix(statePathOrDefault(), "mem:") {
+		// Register as an ephemeral node.
+		o.LoginFlags = controlclient.LoginEphemeral
+	}
 
 	switch goos {
 	default:
@@ -307,6 +341,7 @@ func run() error {
 	socksListener, httpProxyListener := mustStartProxyListeners(args.socksAddr, args.httpProxyAddr)
 
 	dialer := new(tsdial.Dialer) // mutated below (before used)
+	dialer.Logf = logf
 	e, useNetstack, err := createEngine(logf, linkMon, dialer)
 	if err != nil {
 		return fmt.Errorf("createEngine: %w", err)
@@ -316,7 +351,7 @@ func run() error {
 	}
 	if debugMux != nil {
 		if ig, ok := e.(wgengine.InternalsGetter); ok {
-			if _, mc, ok := ig.GetInternals(); ok {
+			if _, mc, _, ok := ig.GetInternals(); ok {
 				debugMux.HandleFunc("/debug/magicsock", mc.ServeHTTPDebug)
 			}
 		}
@@ -331,11 +366,11 @@ func run() error {
 	ns.ProcessSubnets = useNetstack || wrapNetstack
 
 	if useNetstack {
-		dialer.UseNetstackForIP = func(ip netaddr.IP) bool {
+		dialer.UseNetstackForIP = func(ip netip.Addr) bool {
 			_, ok := e.PeerForIP(ip)
 			return ok
 		}
-		dialer.NetstackDialTCP = func(ctx context.Context, dst netaddr.IPPort) (net.Conn, error) {
+		dialer.NetstackDialTCP = func(ctx context.Context, dst netip.AddrPort) (net.Conn, error) {
 			return ns.DialContextTCP(ctx, dst)
 		}
 	}
@@ -380,9 +415,9 @@ func run() error {
 
 	opts := ipnServerOpts()
 
-	store, err := ipnserver.StateStore(statePathOrDefault(), logf)
+	store, err := store.New(logf, statePathOrDefault())
 	if err != nil {
-		return fmt.Errorf("ipnserver.StateStore: %w", err)
+		return fmt.Errorf("store.New: %w", err)
 	}
 	srv, err := ipnserver.New(logf, pol.PublicID.String(), store, e, dialer, nil, opts)
 	if err != nil {
@@ -401,6 +436,7 @@ func run() error {
 	if err != nil {
 		return fmt.Errorf("safesocket.Listen: %v", err)
 	}
+	defer dialer.Close()
 
 	err = srv.Run(ctx, ln)
 	// Cancelation is not an error: it is the only way to stop ipnserver.
@@ -463,10 +499,23 @@ func tryEngine(logf logger.Logf, linkMon *monitor.Mon, dialer *tsdial.Dialer, na
 			return nil, false, fmt.Errorf("createBIRDClient: %w", err)
 		}
 	}
-	if !useNetstack {
+	if useNetstack {
+		if runtime.GOOS == "linux" && distro.Get() == distro.Synology {
+			// On Synology in netstack mode, still init a DNS
+			// manager (directManager) to avoid the health check
+			// warnings in 'tailscale status' about DNS base
+			// configuration being unavailable (from the noop
+			// manager). More in Issue 4017.
+			// TODO(bradfitz): add a Synology-specific DNS manager.
+			conf.DNS, err = dns.NewOSConfigurator(logf, "") // empty interface name
+			if err != nil {
+				return nil, false, fmt.Errorf("dns.NewOSConfigurator: %w", err)
+			}
+		}
+	} else {
 		dev, devName, err := tstun.New(logf, name)
 		if err != nil {
-			tstun.Diagnose(logf, name)
+			tstun.Diagnose(logf, name, err)
 			return nil, false, fmt.Errorf("tstun.New(%q): %w", name, err)
 		}
 		conf.Tun = dev
@@ -526,11 +575,11 @@ func runDebugServer(mux *http.ServeMux, addr string) {
 }
 
 func newNetstack(logf logger.Logf, dialer *tsdial.Dialer, e wgengine.Engine) (*netstack.Impl, error) {
-	tunDev, magicConn, ok := e.(wgengine.InternalsGetter).GetInternals()
+	tunDev, magicConn, dns, ok := e.(wgengine.InternalsGetter).GetInternals()
 	if !ok {
 		return nil, fmt.Errorf("%T is not a wgengine.InternalsGetter", e)
 	}
-	return netstack.Create(logf, tunDev, e, magicConn, dialer)
+	return netstack.Create(logf, tunDev, e, magicConn, dialer, dns)
 }
 
 // mustStartProxyListeners creates listeners for local SOCKS and HTTP
@@ -576,3 +625,17 @@ func mustStartProxyListeners(socksAddr, httpAddr string) (socksListener, httpLis
 
 	return socksListener, httpListener
 }
+
+var beChildFunc = beChild
+
+func beChild(args []string) error {
+	if len(args) == 0 {
+		return errors.New("missing mode argument")
+	}
+	typ := args[0]
+	f, ok := childproc.Code[typ]
+	if !ok {
+		return fmt.Errorf("unknown be-child mode %q", typ)
+	}
+	return f(args[1:])
+}

cmd/tailscaled/tailscaled_bird.go

@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux || darwin || freebsd || openbsd
+//go:build go1.18 && (linux || darwin || freebsd || openbsd)
+// +build go1.18
 // +build linux darwin freebsd openbsd
 
 package main

cmd/tailscaled/tailscaled_notwindows.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !windows
-// +build !windows
+//go:build !windows && go1.18
+// +build !windows,go1.18
 
 package main // import "tailscale.com/cmd/tailscaled"
 

cmd/tailscaled/tailscaled_test.go

@@ -0,0 +1,13 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main // import "tailscale.com/cmd/tailscaled"
+
+import "testing"
+
+func TestNothing(t *testing.T) {
+	// This test does nothing on purpose, so we can run
+	// GODEBUG=memprofilerate=1 go test -v -run=Nothing -memprofile=prof.mem
+	// without any errors about no matching tests.
+}