github actions: resume running Nix-based integration tests

These should be back in a good state, and some tests (ie: TestMITMProxy)
are based on nix tooling so we should do these in CI.

Signed-off-by: Tom DNetto <tom@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-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

@@ -17,13 +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/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 +14,12 @@ 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 go vet
       run: go vet ./...

.github/workflows/vm.yml

@@ -16,15 +16,19 @@ 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: Set up Nix
+        uses: cachix/install-nix-action@v17
+        with:
+          nix_path: nixpkgs=channel:nixos-21.11
 
       - 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
+        run: go test ./tstest/integration/vms -v --timeout=20m --no-s3 --run-vm-tests --distro-regex '(nix|ubuntu)'
         env:
           HOME: "/tmp"
           TMPDIR: "/tmp"

.github/workflows/windows-race.yml

@@ -17,20 +17,31 @@ 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: 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.

Dockerfile

@@ -32,7 +32,7 @@
 #     $ 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
 

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
+1.23.0

api.md

@@ -317,9 +317,14 @@ Allows for updating properties on the device key.
 - 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.
 
+`preauthorized`
+
+- If `true`, don't require machine authorization (if enabled on the tailnet)
+
 ```
 {
-  "keyExpiryDisabled": true
+  "keyExpiryDisabled": true,
+  "preauthorized": true
 }
 ```
 
@@ -631,11 +636,9 @@ 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"]}
-  ]
-}'
+  ]'
 ```
 
 Response:

chirp/chirp.go

@@ -80,7 +80,7 @@ func (b *BIRDClient) EnableProtocol(protocol string) error {
 // 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 ...interface{}) (string, error) {
+func (b *BIRDClient) exec(cmd string, args ...any) (string, error) {
 	if _, err := fmt.Fprintf(b.conn, cmd, args...); err != nil {
 		return "", err
 	}

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/tailscale.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 tailscale contains Tailscale client code.
 package tailscale
 
@@ -16,6 +19,7 @@ import (
 	"io/ioutil"
 	"net"
 	"net/http"
+	"net/http/httptrace"
 	"net/url"
 	"os/exec"
 	"runtime"
@@ -28,6 +32,7 @@ import (
 	"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"
@@ -113,10 +118,7 @@ func doLocalRequestNiceError(req *http.Request) (*http.Response, error) {
 	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]
-			}
+			pathPrefix, _, _ := strings.Cut(path, "?")
 			return nil, fmt.Errorf("Failed to connect to local Tailscale daemon for %s; %s Error: %w", pathPrefix, tailscaledConnectHint(), oe)
 		}
 	}
@@ -183,6 +185,7 @@ func send(ctx context.Context, method, path string, wantStatus int, body io.Read
 		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
@@ -272,6 +275,21 @@ func status(ctx context.Context, queryString string) (*ipnstate.Status, error) {
 	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 IDToken(ctx context.Context, aud string) (*tailcfg.TokenResponse, error) {
+	body, err := 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 WaitingFiles(ctx context.Context) ([]apitype.WaitingFile, error) {
 	body, err := get200(ctx, "/localapi/v0/files/")
 	if err != nil {
@@ -418,6 +436,60 @@ func SetDNS(ctx context.Context, name, value string) error {
 	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 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 := 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 CurrentDERPMap(ctx context.Context) (*tailcfg.DERPMap, error) {
@@ -517,8 +589,8 @@ func tailscaledConnectHint() string {
 	// 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 k, v, ok := strings.Cut(line, "="); ok {
+			st[k] = strings.TrimSpace(v)
 		}
 	}
 	if st["LoadState"] == "loaded" &&

cmd/cloner/cloner.go

@@ -69,14 +69,14 @@ func main() {
 		gen(buf, imports, typ, pkg.Types)
 	}
 
-	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)
@@ -158,7 +158,7 @@ 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 {")
@@ -172,9 +172,15 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
 		if !codegen.ContainsPointers(ft) {
 			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 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:
@@ -234,6 +240,17 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
 	buf.Write(codegen.AssertStructUnchanged(t, thisPkg, name, "Clone", imports))
 }
 
+func isViewType(typ types.Type) bool {
+	t, ok := typ.Underlying().(*types.Struct)
+	if !ok {
+		return false
+	}
+	if t.NumFields() != 1 {
+		return false
+	}
+	return t.Field(0).Name() == "ж"
+}
+
 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"
@@ -24,6 +25,7 @@ import (
 	"strings"
 	"time"
 
+	"golang.org/x/time/rate"
 	"tailscale.com/atomicfile"
 	"tailscale.com/derp"
 	"tailscale.com/derp/derphttp"
@@ -37,7 +39,8 @@ 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")
+	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")
@@ -49,6 +52,9 @@ var (
 	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 (
@@ -207,7 +213,7 @@ 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 +302,7 @@ func main() {
 				}
 			}()
 		}
-		err = httpsrv.ListenAndServeTLS("", "")
+		err = rateLimitedListenAndServeTLS(httpsrv)
 	} else {
 		log.Printf("derper: serving on %s", *addr)
 		err = httpsrv.ListenAndServe()
@@ -317,8 +323,8 @@ 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 +396,63 @@ 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/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/hello/hello.go

@@ -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 +1,135 @@
+# 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. You will
+need to be sure to check this in your application code. If you use OpenResty,
+you may be able to do more complicated access controls than you can with NGINX
+alone.
+
+## 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/mkdeb.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+set -e
+
+CGO_ENABLED=0 GOARCH=amd64 GOOS=linux go build -o tailscale.nginx-auth .
+
+mkpkg \
+    --out tailscale-nginx-auth-0.1.0-amd64.deb \
+    --name=tailscale-nginx-auth \
+    --version=0.1.0 \
+    --type=deb\
+    --arch=amd64 \
+    --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
+
+mkpkg \
+    --out tailscale-nginx-auth-0.1.0-amd64.rpm \
+    --name=tailscale-nginx-auth \
+    --version=0.1.0 \
+    --type=rpm \
+    --arch=amd64 \
+    --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

cmd/nginx-auth/nginx-auth.go

@@ -0,0 +1,120 @@
+// 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"
+	"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
+		}
+
+		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/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/proxy-to-grafana/proxy-to-grafana.go

@@ -0,0 +1,152 @@
+// 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,
+	}
+
+	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)
+	}
+
+	var ln net.Listener
+	if *useHTTPS {
+		ln, err = ts.Listen("tcp", ":443")
+		ln = tls.NewListener(ln, &tls.Config{
+			GetCertificate: tailscale.GetCertificate,
+		})
+
+		go func() {
+			// wait for tailscale to start before trying to fetch cert names
+			for i := 0; i < 60; i++ {
+				st, err := tailscale.Status(context.Background())
+				if err != nil {
+					log.Fatal(err)
+				}
+				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 := tailscale.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) {
+	// 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(), 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, ipPort string) (*tailcfg.UserProfile, error) {
+	whois, err := tailscale.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/cert.go

@@ -79,7 +79,7 @@ func runCert(ctx context.Context, args []string) error {
 	}
 	domain := args[0]
 
-	printf := func(format string, a ...interface{}) {
+	printf := func(format string, a ...any) {
 		printf(format, a...)
 	}
 	if certArgs.certFile == "-" || certArgs.keyFile == "-" {

cmd/tailscale/cli/cli.go

@@ -25,16 +25,18 @@ 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{}) {
+func printf(format string, a ...any) {
 	fmt.Fprintf(Stdout, format, a...)
 }
 
@@ -43,7 +45,7 @@ func printf(format string, a ...interface{}) {
 //
 // 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{}) {
+func outln(a ...any) {
 	fmt.Fprintln(Stdout, a...)
 }
 
@@ -103,8 +105,28 @@ func newFlagSet(name string) *flag.FlagSet {
 	return fs
 }
 
+// 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)
+	}
+	return out
+}
+
 // Run runs the CLI. The args do not include the binary name.
-func Run(args []string) error {
+func Run(args []string) (err error) {
 	if len(args) == 1 && (args[0] == "-V" || args[0] == "--version") {
 		args = []string{"version"}
 	}
@@ -137,6 +159,8 @@ change in the future.
 			ipCmd,
 			statusCmd,
 			pingCmd,
+			ncCmd,
+			sshCmd,
 			versionCmd,
 			webCmd,
 			fileCmd,
@@ -150,11 +174,17 @@ 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) {
@@ -170,7 +200,7 @@ change in the future.
 		}
 	})
 
-	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 +210,7 @@ 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 +220,7 @@ 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

@@ -13,12 +13,12 @@ import (
 	"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"
@@ -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",
@@ -487,7 +487,8 @@ 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)
@@ -630,7 +631,7 @@ func TestPrefsFromUpArgs(t *testing.T) {
 			st: &ipnstate.Status{
 				TailscaleIPs: []netaddr.IP{netaddr.MustParseIP("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 +659,39 @@ 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: []netaddr.IPPrefix{
+					netaddr.MustParseIPPrefix("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) {
@@ -858,7 +892,8 @@ 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 {
@@ -894,132 +929,28 @@ var cmpIP = cmp.Comparer(func(a, b netaddr.IP) 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 := newFlagSet("configure-host")
+		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

@@ -22,6 +22,7 @@ import (
 
 	"github.com/peterbourgon/ff/v3/ffcli"
 	"tailscale.com/client/tailscale"
+	"tailscale.com/hostinfo"
 	"tailscale.com/ipn"
 	"tailscale.com/paths"
 	"tailscale.com/safesocket"
@@ -65,6 +66,11 @@ var debugCmd = &ffcli.Command{
 			Exec:      runEnv,
 			ShortHelp: "print cmd/tailscale environment",
 		},
+		{
+			Name:      "hostinfo",
+			Exec:      runHostinfo,
+			ShortHelp: "print hostinfo",
+		},
 		{
 			Name:      "local-creds",
 			Exec:      runLocalCreds,
@@ -270,6 +276,13 @@ func runEnv(ctx context.Context, args []string) error {
 	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)
 	if err != nil {

cmd/tailscale/cli/file.go

@@ -15,6 +15,7 @@ import (
 	"mime"
 	"net/http"
 	"os"
+	"path"
 	"path/filepath"
 	"strings"
 	"time"
@@ -286,22 +287,171 @@ func runCpTargets(ctx context.Context, args []string) error {
 	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.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 := tailscale.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 = tailscale.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 {
+			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 {
+			printf("wrote %v as %v (%d bytes)\n", wf.Name, writtenFile, size)
+		}
+		if err = tailscale.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 {
+		printf("moved %d/%d files\n", deleted, len(wfs))
+	}
+	return errs
 }
 
 func runFileGet(ctx context.Context, args []string) error {
@@ -318,59 +468,35 @@ 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 {
+				outln(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] {
+		outln(err)
+	}
+	return errs[len(errs)-1]
 }
 
 func wipeInbox(ctx context.Context) error {
@@ -401,9 +527,10 @@ 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 +547,7 @@ 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 +1,35 @@
+// 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 cli
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/peterbourgon/ff/v3/ffcli"
+	"tailscale.com/client/tailscale"
+)
+
+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 := tailscale.IDToken(ctx, args[0])
+	if err != nil {
+		return err
+	}
+
+	fmt.Println(tr.IDToken)
+	return nil
+}

cmd/tailscale/cli/nc.go

@@ -0,0 +1,63 @@
+// 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"
+	"tailscale.com/client/tailscale"
+)
+
+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 := tailscale.Status(ctx)
+	if err != nil {
+		return fixTailscaledConnectError(err)
+	}
+	description, ok := isRunningOrStarting(st)
+	if !ok {
+		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 := tailscale.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/ssh.go

@@ -0,0 +1,186 @@
+// 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"
+	"os"
+	"os/exec"
+	"os/user"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"syscall"
+
+	"github.com/alessio/shellescape"
+	"github.com/peterbourgon/ff/v3/ffcli"
+	"inet.af/netaddr"
+	"tailscale.com/client/tailscale"
+	"tailscale.com/envknob"
+	"tailscale.com/ipn/ipnstate"
+)
+
+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 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 := tailscale.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 := exec.LookPath("ssh")
+	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 := append([]string{
+		ssh,
+
+		"-o", fmt.Sprintf("UserKnownHostsFile %s",
+			shellescape.Quote(knownHostsFile),
+		),
+		"-o", fmt.Sprintf("ProxyCommand %s --socket=%s nc %%h %%p",
+			shellescape.Quote(tailscaleBin),
+			shellescape.Quote(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)
+		username + "@" + hostForSSH,
+	}, argRest...)
+
+	if runtime.GOOS == "windows" {
+		// Don't use syscall.Exec on Windows.
+		cmd := exec.Command(ssh, argv[1:]...)
+		cmd.Stderr = os.Stderr
+		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
+	}
+
+	if envknob.Bool("TS_DEBUG_SSH_EXEC") {
+		log.Printf("Running: %q, %q ...", ssh, argv)
+	}
+	if err := syscall.Exec(ssh, argv, os.Environ()); err != nil {
+		return err
+	}
+	return errors.New("unreachable")
+}
+
+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, _ := netaddr.ParseIP(arg)
+	for _, ps := range st.Peer {
+		dnsName = ps.DNSName
+		if !argIP.IsZero() {
+			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
+}

cmd/tailscale/cli/status.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"flag"
 	"fmt"
 	"net"
@@ -69,7 +70,14 @@ 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 := tailscale.Status
+	if !statusArgs.peers {
+		getStatus = tailscale.StatusWithoutPeers
+	}
+	st, err := getStatus(ctx)
 	if err != nil {
 		return fixTailscaledConnectError(err)
 	}
@@ -136,7 +144,7 @@ func runStatus(ctx context.Context, args []string) error {
 	}
 
 	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),

cmd/tailscale/cli/up.go

@@ -7,6 +7,7 @@ package cli
 import (
 	"context"
 	"encoding/base64"
+	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"flag"
@@ -27,11 +28,11 @@ import (
 	"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"
 )
@@ -103,7 +104,7 @@ func newUpFlagSet(goos string, upArgs *upArgsT) *flag.FlagSet {
 		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")
@@ -193,7 +194,7 @@ type upOutputJSON struct {
 	Error        string `json:",omitempty"` // description of an error
 }
 
-func warnf(format string, args ...interface{}) {
+func warnf(format string, args ...any) {
 	printf("Warning: "+format+"\n", args...)
 }
 
@@ -202,6 +203,26 @@ var (
 	ipv6default = netaddr.MustParseIPPrefix("::/0")
 )
 
+func validateViaPrefix(ipp netaddr.IPPrefix) 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.IP().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) ([]netaddr.IPPrefix, error) {
 	routeMap := map[netaddr.IPPrefix]bool{}
 	if advertiseRoutes != "" {
@@ -215,6 +236,11 @@ func calcAdvertiseRoutes(advertiseRoutes string, advertiseDefaultRoute bool) ([]
 			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 {
@@ -245,65 +271,6 @@ func calcAdvertiseRoutes(advertiseRoutes string, advertiseDefaultRoute bool) ([]
 	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
@@ -743,7 +705,7 @@ 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":
 		return true
 	}
 	return false
@@ -888,8 +850,8 @@ 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() {
@@ -906,7 +868,7 @@ 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 +922,7 @@ 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
 	}

cmd/tailscale/cli/web.go

@@ -269,15 +269,14 @@ 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 +288,7 @@ req.onload = function() {
 req.send(null);
 </script>
 </body></html>
-`))
+`
 
 func webHandler(w http.ResponseWriter, r *http.Request) {
 	if authRedirect(w, r) {
@@ -313,7 +312,7 @@ 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()})

cmd/tailscale/depaware.txt

@@ -1,11 +1,18 @@
 tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/depaware)
 
+        github.com/alessio/shellescape                               from tailscale.com/cmd/tailscale/cli
    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/golang/groupcache/lru                             from tailscale.com/net/dnscache
+   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
+   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
@@ -31,7 +38,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         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/controlknobs                           from tailscale.com/net/portmapper
         tailscale.com/derp                                           from tailscale.com/derp/derphttp
@@ -39,10 +46,9 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
    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/flowtrack                                  from tailscale.com/wgengine/filter+
@@ -51,6 +57,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         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
@@ -59,7 +66,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
      💣 tailscale.com/net/tshttpproxy                                from tailscale.com/derp/derphttp+
      💣 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+
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
      💣 tailscale.com/tstime/mono                                    from tailscale.com/tstime/rate
@@ -75,11 +82,15 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         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+
+   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+
+   W    tailscale.com/util/winutil                                   from tailscale.com/hostinfo
+   W 💣 tailscale.com/util/winutil/vss                               from tailscale.com/util/winutil
         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
@@ -92,8 +103,8 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         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
@@ -177,18 +188,19 @@ 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 golang.org/x/sync/singleflight+
         sort                                                         from compress/flate+
         strconv                                                      from compress/flate+
         strings                                                      from bufio+

cmd/tailscale/tailscale.go

@@ -17,6 +17,7 @@ import (
 
 func main() {
 	args := os.Args[1:]
+	args = cli.CleanUpArgs(args)
 	if name, _ := os.Executable(); strings.HasSuffix(filepath.Base(name), ".cgi") {
 		args = []string{"web", "-cgi"}
 	}

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 (

cmd/tailscaled/depaware.txt

@@ -3,10 +3,10 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    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 +16,7 @@ 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 +36,7 @@ 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+
@@ -61,11 +61,10 @@ 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
    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+
    L    github.com/insomniacslk/dhcp/dhcpv4                          from tailscale.com/net/tstun
@@ -74,7 +73,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    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
@@ -83,6 +82,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         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
+   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
@@ -90,6 +90,10 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
      💣 github.com/mitchellh/go-ps                                   from tailscale.com/safesocket
    W    github.com/pkg/errors                                        from github.com/tailscale/certstore
    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+
@@ -98,6 +102,7 @@ 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+
@@ -125,8 +130,8 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         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
@@ -168,7 +173,10 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
   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/control/controlclient                          from tailscale.com/ipn/ipnlocal+
+        tailscale.com/cmd/tailscaled/childproc                       from tailscale.com/cmd/tailscaled+
+        tailscale.com/control/controlbase                            from tailscale.com/control/controlclient+
+        tailscale.com/control/controlclient                          from tailscale.com/cmd/tailscaled+
+        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+
@@ -183,33 +191,39 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/ipn/ipnstate                                   from tailscale.com/client/tailscale+
         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                                        from tailscale.com/cmd/tailscaled+
         tailscale.com/logtail/backoff                                from tailscale.com/cmd/tailscaled+
         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/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/netcheck                                   from tailscale.com/wgengine/magicsock
-        tailscale.com/net/neterror                                   from tailscale.com/net/netcheck+
+        tailscale.com/net/neterror                                   from tailscale.com/net/dns/resolver+
         tailscale.com/net/netknob                                    from tailscale.com/logpolicy+
         tailscale.com/net/netns                                      from tailscale.com/cmd/tailscaled+
      💣 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/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/tsaddr                                     from tailscale.com/ipn+
         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+
@@ -217,8 +231,10 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         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+
+  LD 💣 tailscale.com/ssh/tailssh                                    from tailscale.com/wgengine/netstack
+        tailscale.com/syncs                                          from tailscale.com/control/controlknobs+
         tailscale.com/tailcfg                                        from tailscale.com/client/tailscale+
+  LD    tailscale.com/tempfork/gliderlabs/ssh                        from tailscale.com/ssh/tailssh
    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+
@@ -237,14 +253,16 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         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/cmd/tailscaled+
+  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/netconv                                   from tailscale.com/wgengine/magicsock
         tailscale.com/util/osshare                                   from tailscale.com/cmd/tailscaled+
         tailscale.com/util/pidowner                                  from tailscale.com/ipn/ipnserver
         tailscale.com/util/racebuild                                 from tailscale.com/logpolicy
@@ -257,9 +275,9 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    W    tailscale.com/wf                                             from tailscale.com/cmd/tailscaled
         tailscale.com/wgengine                                       from tailscale.com/cmd/tailscaled+
         tailscale.com/wgengine/filter                                from tailscale.com/control/controlclient+
-        tailscale.com/wgengine/magicsock                             from tailscale.com/wgengine+
+        tailscale.com/wgengine/magicsock                             from tailscale.com/ipn/ipnlocal+
         tailscale.com/wgengine/monitor                               from tailscale.com/cmd/tailscaled+
-     💣 tailscale.com/wgengine/netstack                              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/wgcfg                                 from tailscale.com/ipn/ipnlocal+
         tailscale.com/wgengine/wgcfg/nmcfg                           from tailscale.com/ipn/ipnlocal
@@ -267,34 +285,34 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    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/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/sync/singleflight                               from tailscale.com/control/controlclient+
         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+
@@ -310,7 +328,7 @@ 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+
@@ -334,7 +352,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         crypto/tls                                                   from github.com/aws/aws-sdk-go-v2/aws/transport/http+
         crypto/x509                                                  from crypto/tls+
         crypto/x509/pkix                                             from crypto/x509+
-        embed                                                        from tailscale.com/net/dns+
+        embed                                                        from crypto/elliptic+
         encoding                                                     from encoding/json+
         encoding/asn1                                                from crypto/x509+
         encoding/base64                                              from encoding/json+
@@ -356,6 +374,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         io/fs                                                        from crypto/rand+
         io/ioutil                                                    from github.com/aws/aws-sdk-go-v2/aws/protocol/query+
         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+
@@ -369,6 +388,7 @@ 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/netip                                                    from golang.zx2c4.com/wireguard/conn+
         net/textproto                                                from github.com/aws/aws-sdk-go-v2/aws/signer/v4+
         net/url                                                      from crypto/x509+
         os                                                           from crypto/rand+

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/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.
 //
@@ -22,15 +25,17 @@ import (
 	"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 +125,10 @@ 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)
-	}
-
 	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")
@@ -123,7 +137,7 @@ 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", paths.DefaultTailscaledStateFile(), "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")
 	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")
@@ -238,8 +252,19 @@ func ipnServerOpts() (o ipnserver.Options) {
 			o.VarRoot = dir
 		}
 	}
+	if strings.HasPrefix(statePathOrDefault(), "mem:") {
+		// Register as an ephemeral node.
+		o.LoginFlags = controlclient.LoginEphemeral
+	}
 
 	switch goos {
+	case "js":
+		// The js/wasm client has no state storage so for now
+		// treat all interactive logins as ephemeral.
+		// TODO(bradfitz): if we start using browser LocalStorage
+		// or something, then rethink this.
+		o.LoginFlags = controlclient.LoginEphemeral
+		fallthrough
 	default:
 		o.SurviveDisconnects = true
 		o.AutostartStateKey = ipn.GlobalDaemonStateKey
@@ -380,9 +405,9 @@ 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 {
@@ -463,7 +488,20 @@ 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)
@@ -576,3 +614,17 @@ 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.
+}

cmd/tailscaled/tailscaled_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 "tailscale.com/cmd/tailscaled"
 
 // TODO: check if administrator, like tswin does.
@@ -31,6 +34,7 @@ import (
 	"inet.af/netaddr"
 	"tailscale.com/envknob"
 	"tailscale.com/ipn/ipnserver"
+	"tailscale.com/ipn/store"
 	"tailscale.com/logpolicy"
 	"tailscale.com/net/dns"
 	"tailscale.com/net/tsdial"
@@ -74,7 +78,7 @@ func (service *ipnService) Execute(args []string, r <-chan svc.ChangeRequest, ch
 	changes <- svc.Status{State: svc.StartPending}
 
 	svcAccepts := svc.AcceptStop
-	if winutil.GetRegInteger("FlushDNSOnSessionUnlock", 0) != 0 {
+	if winutil.GetPolicyInteger("FlushDNSOnSessionUnlock", 0) != 0 {
 		svcAccepts |= svc.AcceptSessionChange
 	}
 
@@ -335,8 +339,7 @@ func startIPNServer(ctx context.Context, logid string) error {
 			return nil, fmt.Errorf("%w\n\nlogid: %v", res.Err, logid)
 		}
 	}
-
-	store, err := ipnserver.StateStore(statePathOrDefault(), logf)
+	store, err := store.New(logf, statePathOrDefault())
 	if err != nil {
 		return err
 	}

cmd/testcontrol/testcontrol.go

@@ -46,10 +46,10 @@ type fakeTB struct {
 }
 
 func (t fakeTB) Cleanup(_ func()) {}
-func (t fakeTB) Error(args ...interface{}) {
+func (t fakeTB) Error(args ...any) {
 	t.Fatal(args...)
 }
-func (t fakeTB) Errorf(format string, args ...interface{}) {
+func (t fakeTB) Errorf(format string, args ...any) {
 	t.Fatalf(format, args...)
 }
 func (t fakeTB) Fail() {
@@ -61,17 +61,17 @@ func (t fakeTB) FailNow() {
 func (t fakeTB) Failed() bool {
 	return false
 }
-func (t fakeTB) Fatal(args ...interface{}) {
+func (t fakeTB) Fatal(args ...any) {
 	log.Fatal(args...)
 }
-func (t fakeTB) Fatalf(format string, args ...interface{}) {
+func (t fakeTB) Fatalf(format string, args ...any) {
 	log.Fatalf(format, args...)
 }
 func (t fakeTB) Helper() {}
-func (t fakeTB) Log(args ...interface{}) {
+func (t fakeTB) Log(args ...any) {
 	log.Print(args...)
 }
-func (t fakeTB) Logf(format string, args ...interface{}) {
+func (t fakeTB) Logf(format string, args ...any) {
 	log.Printf(format, args...)
 }
 func (t fakeTB) Name() string {
@@ -80,13 +80,13 @@ func (t fakeTB) Name() string {
 func (t fakeTB) Setenv(key string, value string) {
 	panic("not implemented")
 }
-func (t fakeTB) Skip(args ...interface{}) {
+func (t fakeTB) Skip(args ...any) {
 	t.Fatal("skipped")
 }
 func (t fakeTB) SkipNow() {
 	t.Fatal("skipnow")
 }
-func (t fakeTB) Skipf(format string, args ...interface{}) {
+func (t fakeTB) Skipf(format string, args ...any) {
 	t.Logf(format, args...)
 	t.Fatal("skipped")
 }

cmd/tsshd/tsshd.go

@@ -31,11 +31,11 @@ import (
 	"unsafe"
 
 	"github.com/creack/pty"
-	"github.com/gliderlabs/ssh"
-	gossh "golang.org/x/crypto/ssh"
+	gossh "github.com/tailscale/golang-x-crypto/ssh"
 	"inet.af/netaddr"
 	"tailscale.com/net/interfaces"
 	"tailscale.com/net/tsaddr"
+	"tailscale.com/tempfork/gliderlabs/ssh"
 )
 
 var (

control/controlbase/conn.go

@@ -52,10 +52,11 @@ type rxState struct {
 	sync.Mutex
 	cipher    cipher.AEAD
 	nonce     nonce
-	buf       [maxMessageSize]byte
-	n         int    // number of valid bytes in buf
-	next      int    // offset of next undecrypted packet
-	plaintext []byte // slice into buf of decrypted bytes
+	buf       *maxMsgBuffer   // or nil when reads exhausted
+	n         int             // number of valid bytes in buf
+	next      int             // offset of next undecrypted packet
+	plaintext []byte          // slice into buf of decrypted bytes
+	hdrBuf    [headerLen]byte // small buffer used when buf is nil
 }
 
 // txState is all the Conn state that Write uses.
@@ -63,7 +64,6 @@ type txState struct {
 	sync.Mutex
 	cipher cipher.AEAD
 	nonce  nonce
-	buf    [maxMessageSize]byte
 	err    error // records the first partial write error for all future calls
 }
 
@@ -89,6 +89,10 @@ func (c *Conn) Peer() key.MachinePublic {
 // readNLocked reads into c.rx.buf until buf contains at least total
 // bytes. Returns a slice of the total bytes in rxBuf, or an
 // error if fewer than total bytes are available.
+//
+// It may be called with a nil c.rx.buf only if total == headerLen.
+//
+// On success, c.rx.buf will be non-nil.
 func (c *Conn) readNLocked(total int) ([]byte, error) {
 	if total > maxMessageSize {
 		return nil, errReadTooBig{total}
@@ -97,8 +101,26 @@ func (c *Conn) readNLocked(total int) ([]byte, error) {
 		if total <= c.rx.n {
 			return c.rx.buf[:total], nil
 		}
-
-		n, err := c.conn.Read(c.rx.buf[c.rx.n:])
+		var n int
+		var err error
+		if c.rx.buf == nil {
+			if c.rx.n != 0 || total != headerLen {
+				panic("unexpected")
+			}
+			// Optimization to reduce memory usage.
+			// Most connections are blocked forever waiting for
+			// a read, so we don't want c.rx.buf to be allocated until
+			// we know there's data to read. Instead, when we're
+			// waiting for data to arrive here, read into the
+			// 3 byte hdrBuf:
+			n, err = c.conn.Read(c.rx.hdrBuf[:])
+			if n > 0 {
+				c.rx.buf = getMaxMsgBuffer()
+				copy(c.rx.buf[:], c.rx.hdrBuf[:n])
+			}
+		} else {
+			n, err = c.conn.Read(c.rx.buf[c.rx.n:])
+		}
 		c.rx.n += n
 		if err != nil {
 			return nil, err
@@ -134,19 +156,19 @@ func (c *Conn) decryptLocked(msg []byte) (err error) {
 	return err
 }
 
-// encryptLocked encrypts plaintext into c.tx.buf (including the
+// encryptLocked encrypts plaintext into buf (including the
 // packet header) and returns a slice of the ciphertext, or an error
 // if the cipher is exhausted (i.e. can no longer be used safely).
-func (c *Conn) encryptLocked(plaintext []byte) ([]byte, error) {
+func (c *Conn) encryptLocked(plaintext []byte, buf *maxMsgBuffer) ([]byte, error) {
 	if !c.tx.nonce.Valid() {
 		// Received 2^64-1 messages on this cipher state. Connection
 		// is no longer usable.
 		return nil, errCipherExhausted{}
 	}
 
-	c.tx.buf[0] = msgTypeRecord
-	binary.BigEndian.PutUint16(c.tx.buf[1:headerLen], uint16(len(plaintext)+chp.Overhead))
-	ret := c.tx.cipher.Seal(c.tx.buf[:headerLen], c.tx.nonce[:], plaintext, nil)
+	buf[0] = msgTypeRecord
+	binary.BigEndian.PutUint16(buf[1:headerLen], uint16(len(plaintext)+chp.Overhead))
+	ret := c.tx.cipher.Seal(buf[:headerLen], c.tx.nonce[:], plaintext, nil)
 	c.tx.nonce.Increment()
 
 	return ret, nil
@@ -191,6 +213,14 @@ func (c *Conn) decryptOneLocked() error {
 		c.rx.next = 0
 	}
 
+	// Return our buffer to the pool if it's empty, lest we be
+	// blocked in a long Read call, reading the 3 byte header. We
+	// don't to keep that buffer unnecessarily alive.
+	if c.rx.n == 0 && c.rx.next == 0 && c.rx.buf != nil {
+		bufPool.Put(c.rx.buf)
+		c.rx.buf = nil
+	}
+
 	bs, err := c.readNLocked(headerLen)
 	if err != nil {
 		return err
@@ -227,6 +257,12 @@ func (c *Conn) Read(bs []byte) (int, error) {
 	}
 	n := copy(bs, c.rx.plaintext)
 	c.rx.plaintext = c.rx.plaintext[n:]
+
+	// Lose slice's underlying array pointer to unneeded memory so
+	// GC can collect more.
+	if len(c.rx.plaintext) == 0 {
+		c.rx.plaintext = nil
+	}
 	return n, nil
 }
 
@@ -257,6 +293,9 @@ func (c *Conn) Write(bs []byte) (n int, err error) {
 		return 0, net.ErrClosed
 	}
 
+	buf := getMaxMsgBuffer()
+	defer bufPool.Put(buf)
+
 	var sent int
 	for len(bs) > 0 {
 		toSend := bs
@@ -265,20 +304,18 @@ func (c *Conn) Write(bs []byte) (n int, err error) {
 		}
 		bs = bs[len(toSend):]
 
-		ciphertext, err := c.encryptLocked(toSend)
+		ciphertext, err := c.encryptLocked(toSend, buf)
 		if err != nil {
-			return 0, err
+			return sent, err
 		}
-
-		n, err := c.conn.Write(ciphertext)
-		sent += n
-		if err != nil {
+		if _, err := c.conn.Write(ciphertext); err != nil {
 			// Return the raw error on the Write that actually
 			// failed. For future writes, return that error wrapped in
 			// a desync error.
 			c.tx.err = errPartialWrite{err}
 			return sent, err
 		}
+		sent += len(toSend)
 	}
 	return sent, nil
 }
@@ -357,3 +394,16 @@ func (n *nonce) Increment() {
 	}
 	binary.BigEndian.PutUint64(n[4:], 1+binary.BigEndian.Uint64(n[4:]))
 }
+
+type maxMsgBuffer [maxMessageSize]byte
+
+// bufPool holds the temporary buffers for Conn.Read & Write.
+var bufPool = &sync.Pool{
+	New: func() interface{} {
+		return new(maxMsgBuffer)
+	},
+}
+
+func getMaxMsgBuffer() *maxMsgBuffer {
+	return bufPool.Get().(*maxMsgBuffer)
+}

control/controlbase/conn_test.go

@@ -13,10 +13,12 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"runtime"
 	"strings"
 	"sync"
 	"testing"
 	"testing/iotest"
+	"time"
 
 	chp "golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/net/nettest"
@@ -24,6 +26,8 @@ import (
 	"tailscale.com/types/key"
 )
 
+const testProtocolVersion = 1
+
 func TestMessageSize(t *testing.T) {
 	// This test is a regression guard against someone looking at
 	// maxCiphertextSize, going "huh, we could be more efficient if it
@@ -205,7 +209,7 @@ func TestConnStd(t *testing.T) {
 			c2, err = Server(context.Background(), s2, controlKey, nil)
 			serverErr <- err
 		}()
-		c1, err = Client(context.Background(), s1, machineKey, controlKey.Public())
+		c1, err = Client(context.Background(), s1, machineKey, controlKey.Public(), testProtocolVersion)
 		if err != nil {
 			s1.Close()
 			s2.Close()
@@ -224,6 +228,81 @@ func TestConnStd(t *testing.T) {
 	})
 }
 
+// tests that the idle memory overhead of a Conn blocked in a read is
+// reasonable (under 2K). It was previously over 8KB with two 4KB
+// buffers for rx/tx. This make sure we don't regress. Hopefully it
+// doesn't turn into a flaky test. If so, const max can be adjusted,
+// or it can be deleted or reworked.
+func TestConnMemoryOverhead(t *testing.T) {
+	num := 1000
+	if testing.Short() {
+		num = 100
+	}
+	ng0 := runtime.NumGoroutine()
+
+	runtime.GC()
+	var ms0 runtime.MemStats
+	runtime.ReadMemStats(&ms0)
+
+	var closers []io.Closer
+	closeAll := func() {
+		for _, c := range closers {
+			c.Close()
+		}
+		closers = nil
+	}
+	defer closeAll()
+
+	for i := 0; i < num; i++ {
+		client, server := pair(t)
+		closers = append(closers, client, server)
+		go func() {
+			var buf [1]byte
+			client.Read(buf[:])
+		}()
+	}
+
+	t0 := time.Now()
+	deadline := t0.Add(3 * time.Second)
+	var ngo int
+	for time.Now().Before(deadline) {
+		runtime.GC()
+		ngo = runtime.NumGoroutine()
+		if ngo >= num {
+			break
+		}
+		time.Sleep(10 * time.Millisecond)
+	}
+	if ngo < num {
+		t.Fatalf("only %v goroutines; expected %v+", ngo, num)
+	}
+	runtime.GC()
+	var ms runtime.MemStats
+	runtime.ReadMemStats(&ms)
+	growthTotal := int64(ms.HeapAlloc) - int64(ms0.HeapAlloc)
+	growthEach := float64(growthTotal) / float64(num)
+	t.Logf("Alloced %v bytes, %.2f B/each", growthTotal, growthEach)
+	const max = 2000
+	if growthEach > max {
+		t.Errorf("allocated more than expected; want max %v bytes/each", max)
+	}
+
+	closeAll()
+
+	// And make sure our goroutines go away too.
+	deadline = time.Now().Add(3 * time.Second)
+	for time.Now().Before(deadline) {
+		ngo = runtime.NumGoroutine()
+		if ngo < ng0+num/10 {
+			break
+		}
+		time.Sleep(10 * time.Millisecond)
+	}
+	if ngo >= ng0+num/10 {
+		t.Errorf("goroutines didn't go back down; started at %v, now %v", ng0, ngo)
+	}
+}
+
 // mkConns creates synthetic Noise Conns wrapping the given net.Conns.
 // This function is for testing just the Conn transport logic without
 // having to muck about with Noise handshakes.
@@ -323,7 +402,7 @@ func pairWithConns(t *testing.T, clientConn, serverConn net.Conn) (*Conn, *Conn)
 		serverErr <- err
 	}()
 
-	client, err := Client(context.Background(), clientConn, machineKey, controlKey.Public())
+	client, err := Client(context.Background(), clientConn, machineKey, controlKey.Public(), testProtocolVersion)
 	if err != nil {
 		t.Fatalf("client connection failed: %v", err)
 	}

control/controlbase/handshake.go

@@ -32,7 +32,7 @@ const (
 	protocolName = "Noise_IK_25519_ChaChaPoly_BLAKE2s"
 	// protocolVersion is the version of the control protocol that
 	// Client will use when initiating a handshake.
-	protocolVersion uint16 = 1
+	//protocolVersion uint16 = 1
 	// protocolVersionPrefix is the name portion of the protocol
 	// name+version string that gets mixed into the handshake as a
 	// prologue.
@@ -66,7 +66,7 @@ type HandshakeContinuation func(context.Context, net.Conn) (*Conn, error)
 // protocol switching. By splitting the handshake into an initial
 // message and a continuation, we can embed the handshake initiation
 // into the HTTP protocol switching request and avoid a bit of delay.
-func ClientDeferred(machineKey key.MachinePrivate, controlKey key.MachinePublic) (initialHandshake []byte, continueHandshake HandshakeContinuation, err error) {
+func ClientDeferred(machineKey key.MachinePrivate, controlKey key.MachinePublic, protocolVersion uint16) (initialHandshake []byte, continueHandshake HandshakeContinuation, err error) {
 	var s symmetricState
 	s.Initialize()
 
@@ -78,7 +78,7 @@ func ClientDeferred(machineKey key.MachinePrivate, controlKey key.MachinePublic)
 	s.MixHash(controlKey.UntypedBytes())
 
 	// -> e, es, s, ss
-	init := mkInitiationMessage()
+	init := mkInitiationMessage(protocolVersion)
 	machineEphemeral := key.NewMachine()
 	machineEphemeralPub := machineEphemeral.Public()
 	copy(init.EphemeralPub(), machineEphemeralPub.UntypedBytes())
@@ -96,7 +96,7 @@ func ClientDeferred(machineKey key.MachinePrivate, controlKey key.MachinePublic)
 	s.EncryptAndHash(cipher, init.Tag(), nil) // empty message payload
 
 	cont := func(ctx context.Context, conn net.Conn) (*Conn, error) {
-		return continueClientHandshake(ctx, conn, &s, machineKey, machineEphemeral, controlKey)
+		return continueClientHandshake(ctx, conn, &s, machineKey, machineEphemeral, controlKey, protocolVersion)
 	}
 	return init[:], cont, nil
 }
@@ -107,8 +107,8 @@ func ClientDeferred(machineKey key.MachinePrivate, controlKey key.MachinePublic)
 // This is a helper for when you don't need the fancy
 // continuation-style handshake, and just want to synchronously
 // upgrade a net.Conn to a secure transport.
-func Client(ctx context.Context, conn net.Conn, machineKey key.MachinePrivate, controlKey key.MachinePublic) (*Conn, error) {
-	init, cont, err := ClientDeferred(machineKey, controlKey)
+func Client(ctx context.Context, conn net.Conn, machineKey key.MachinePrivate, controlKey key.MachinePublic, protocolVersion uint16) (*Conn, error) {
+	init, cont, err := ClientDeferred(machineKey, controlKey, protocolVersion)
 	if err != nil {
 		return nil, err
 	}
@@ -118,7 +118,7 @@ func Client(ctx context.Context, conn net.Conn, machineKey key.MachinePrivate, c
 	return cont(ctx, conn)
 }
 
-func continueClientHandshake(ctx context.Context, conn net.Conn, s *symmetricState, machineKey, machineEphemeral key.MachinePrivate, controlKey key.MachinePublic) (*Conn, error) {
+func continueClientHandshake(ctx context.Context, conn net.Conn, s *symmetricState, machineKey, machineEphemeral key.MachinePrivate, controlKey key.MachinePublic, protocolVersion uint16) (*Conn, error) {
 	// No matter what, this function can only run once per s. Ensure
 	// attempted reuse causes a panic.
 	defer func() {
@@ -239,9 +239,12 @@ func Server(ctx context.Context, conn net.Conn, controlKey key.MachinePrivate, o
 	} else if _, err := io.ReadFull(conn, init.Header()); err != nil {
 		return nil, err
 	}
-	if init.Version() != protocolVersion {
-		return nil, sendErr("unsupported protocol version")
-	}
+	// Just a rename to make it more obvious what the value is. In the
+	// current implementation we don't need to block any protocol
+	// versions at this layer, it's safe to let the handshake proceed
+	// and then let the caller make decisions based on the agreed-upon
+	// protocol version.
+	clientVersion := init.Version()
 	if init.Type() != msgTypeInitiation {
 		return nil, sendErr("unexpected handshake message type")
 	}
@@ -257,7 +260,7 @@ func Server(ctx context.Context, conn net.Conn, controlKey key.MachinePrivate, o
 
 	// prologue. Can only do this once we at least think the client is
 	// handshaking using a supported version.
-	s.MixHash(protocolVersionPrologue(protocolVersion))
+	s.MixHash(protocolVersionPrologue(clientVersion))
 
 	// <- s
 	// ...
@@ -310,7 +313,7 @@ func Server(ctx context.Context, conn net.Conn, controlKey key.MachinePrivate, o
 
 	c := &Conn{
 		conn:          conn,
-		version:       protocolVersion,
+		version:       clientVersion,
 		peer:          machineKey,
 		handshakeHash: s.h,
 		tx: txState{

control/controlbase/handshake_test.go

@@ -30,7 +30,7 @@ func TestHandshake(t *testing.T) {
 		serverErr <- err
 	}()
 
-	client, err := Client(context.Background(), clientConn, clientKey, serverKey.Public())
+	client, err := Client(context.Background(), clientConn, clientKey, serverKey.Public(), testProtocolVersion)
 	if err != nil {
 		t.Fatalf("client connection failed: %v", err)
 	}
@@ -42,8 +42,8 @@ func TestHandshake(t *testing.T) {
 		t.Fatal("client and server disagree on handshake hash")
 	}
 
-	if client.ProtocolVersion() != int(protocolVersion) {
-		t.Fatalf("client reporting wrong protocol version %d, want %d", client.ProtocolVersion(), protocolVersion)
+	if client.ProtocolVersion() != int(testProtocolVersion) {
+		t.Fatalf("client reporting wrong protocol version %d, want %d", client.ProtocolVersion(), testProtocolVersion)
 	}
 	if client.ProtocolVersion() != server.ProtocolVersion() {
 		t.Fatalf("peers disagree on protocol version, client=%d server=%d", client.ProtocolVersion(), server.ProtocolVersion())
@@ -82,7 +82,7 @@ func TestNoReuse(t *testing.T) {
 			serverErr <- err
 		}()
 
-		client, err := Client(context.Background(), clientConn, clientKey, serverKey.Public())
+		client, err := Client(context.Background(), clientConn, clientKey, serverKey.Public(), testProtocolVersion)
 		if err != nil {
 			t.Fatalf("client connection failed: %v", err)
 		}
@@ -181,7 +181,7 @@ func TestTampering(t *testing.T) {
 			serverErr <- err
 		}()
 
-		_, err := Client(context.Background(), clientConn, clientKey, serverKey.Public())
+		_, err := Client(context.Background(), clientConn, clientKey, serverKey.Public(), testProtocolVersion)
 		if err == nil {
 			t.Fatal("client connection succeeded despite tampering")
 		}
@@ -204,7 +204,7 @@ func TestTampering(t *testing.T) {
 			serverErr <- err
 		}()
 
-		_, err := Client(context.Background(), clientConn, clientKey, serverKey.Public())
+		_, err := Client(context.Background(), clientConn, clientKey, serverKey.Public(), testProtocolVersion)
 		if err == nil {
 			t.Fatal("client connection succeeded despite tampering")
 		}
@@ -231,7 +231,7 @@ func TestTampering(t *testing.T) {
 			serverErr <- err
 		}()
 
-		client, err := Client(context.Background(), clientConn, clientKey, serverKey.Public())
+		client, err := Client(context.Background(), clientConn, clientKey, serverKey.Public(), testProtocolVersion)
 		if err != nil {
 			t.Fatalf("client handshake failed: %v", err)
 		}
@@ -281,7 +281,7 @@ func TestTampering(t *testing.T) {
 			}
 		}()
 
-		client, err := Client(context.Background(), clientConn, clientKey, serverKey.Public())
+		client, err := Client(context.Background(), clientConn, clientKey, serverKey.Public(), testProtocolVersion)
 		if err != nil {
 			t.Fatalf("client handshake failed: %v", err)
 		}

control/controlbase/interop_test.go

@@ -77,7 +77,7 @@ func TestInteropServer(t *testing.T) {
 	)
 
 	go func() {
-		client, err := Client(context.Background(), s1, machineKey, controlKey.Public())
+		client, err := Client(context.Background(), s1, machineKey, controlKey.Public(), testProtocolVersion)
 		clientErr <- err
 		if err != nil {
 			return
@@ -121,11 +121,11 @@ func noiseExplorerClient(conn net.Conn, controlKey key.MachinePublic, machineKey
 	copy(mk.public_key[:], machineKey.Public().UntypedBytes())
 	var peerKey [32]byte
 	copy(peerKey[:], controlKey.UntypedBytes())
-	session := InitSession(true, protocolVersionPrologue(protocolVersion), mk, peerKey)
+	session := InitSession(true, protocolVersionPrologue(testProtocolVersion), mk, peerKey)
 
 	_, msg1 := SendMessage(&session, nil)
 	var hdr [initiationHeaderLen]byte
-	binary.BigEndian.PutUint16(hdr[:2], protocolVersion)
+	binary.BigEndian.PutUint16(hdr[:2], testProtocolVersion)
 	hdr[2] = msgTypeInitiation
 	binary.BigEndian.PutUint16(hdr[3:5], 96)
 	if _, err := conn.Write(hdr[:]); err != nil {
@@ -193,7 +193,7 @@ func noiseExplorerServer(conn net.Conn, controlKey key.MachinePrivate, wantMachi
 	var mk keypair
 	copy(mk.private_key[:], controlKey.UntypedBytes())
 	copy(mk.public_key[:], controlKey.Public().UntypedBytes())
-	session := InitSession(false, protocolVersionPrologue(protocolVersion), mk, [32]byte{})
+	session := InitSession(false, protocolVersionPrologue(testProtocolVersion), mk, [32]byte{})
 
 	var buf [1024]byte
 	if _, err := io.ReadFull(conn, buf[:101]); err != nil {

control/controlbase/messages.go

@@ -39,9 +39,9 @@ const (
 // 16b: message tag (authenticates the whole message)
 type initiationMessage [101]byte
 
-func mkInitiationMessage() initiationMessage {
+func mkInitiationMessage(protocolVersion uint16) initiationMessage {
 	var ret initiationMessage
-	binary.BigEndian.PutUint16(ret[:2], uint16(protocolVersion))
+	binary.BigEndian.PutUint16(ret[:2], protocolVersion)
 	ret[2] = msgTypeInitiation
 	binary.BigEndian.PutUint16(ret[3:5], uint16(len(ret.Payload())))
 	return ret

control/controlclient/auto.go

@@ -7,6 +7,7 @@ package controlclient
 import (
 	"context"
 	"fmt"
+	"net/http"
 	"sync"
 	"time"
 
@@ -91,7 +92,7 @@ func NewNoStart(opts Options) (*Auto, error) {
 		return nil, err
 	}
 	if opts.Logf == nil {
-		opts.Logf = func(fmt string, args ...interface{}) {}
+		opts.Logf = func(fmt string, args ...any) {}
 	}
 	if opts.TimeNow == nil {
 		opts.TimeNow = time.Now
@@ -266,9 +267,9 @@ func (c *Auto) authRoutine() {
 		goal := c.loginGoal
 		ctx := c.authCtx
 		if goal != nil {
-			c.logf("authRoutine: %s; wantLoggedIn=%v", c.state, goal.wantLoggedIn)
+			c.logf("[v1] authRoutine: %s; wantLoggedIn=%v", c.state, goal.wantLoggedIn)
 		} else {
-			c.logf("authRoutine: %s; goal=nil paused=%v", c.state, c.paused)
+			c.logf("[v1] authRoutine: %s; goal=nil paused=%v", c.state, c.paused)
 		}
 		c.mu.Unlock()
 
@@ -414,7 +415,7 @@ func (c *Auto) mapRoutine() {
 			}
 			continue
 		}
-		c.logf("mapRoutine: %s", c.state)
+		c.logf("[v1] mapRoutine: %s", c.state)
 		loggedIn := c.loggedIn
 		ctx := c.mapCtx
 		c.mu.Unlock()
@@ -445,9 +446,9 @@ func (c *Auto) mapRoutine() {
 
 			select {
 			case <-ctx.Done():
-				c.logf("mapRoutine: context done.")
+				c.logf("[v1] mapRoutine: context done.")
 			case <-c.newMapCh:
-				c.logf("mapRoutine: new map needed while idle.")
+				c.logf("[v1] mapRoutine: new map needed while idle.")
 			}
 		} else {
 			// Be sure this is false when we're not inside
@@ -657,6 +658,10 @@ func (c *Auto) Logout(ctx context.Context) error {
 	}
 }
 
+func (c *Auto) SetExpirySooner(ctx context.Context, expiry time.Time) error {
+	return c.direct.SetExpirySooner(ctx, expiry)
+}
+
 // UpdateEndpoints sets the client's discovered endpoints and sends
 // them to the control server if they've changed.
 //
@@ -677,6 +682,7 @@ func (c *Auto) Shutdown() {
 	c.mu.Lock()
 	inSendStatus := c.inSendStatus
 	closed := c.closed
+	direct := c.direct
 	if !closed {
 		c.closed = true
 		c.statusFunc = nil
@@ -691,6 +697,9 @@ func (c *Auto) Shutdown() {
 		<-c.authDone
 		c.cancelMapUnsafely()
 		<-c.mapDone
+		if direct != nil {
+			direct.Close()
+		}
 		c.logf("Client.Shutdown done.")
 	}
 }
@@ -717,3 +726,7 @@ func (c *Auto) TestOnlyTimeNow() time.Time {
 func (c *Auto) SetDNS(ctx context.Context, req *tailcfg.SetDNSRequest) error {
 	return c.direct.SetDNS(ctx, req)
 }
+
+func (c *Auto) DoNoiseRequest(req *http.Request) (*http.Response, error) {
+	return c.direct.DoNoiseRequest(req)
+}

control/controlclient/client.go

@@ -11,6 +11,8 @@ package controlclient
 
 import (
 	"context"
+	"net/http"
+	"time"
 
 	"tailscale.com/tailcfg"
 )
@@ -45,6 +47,9 @@ type Client interface {
 	// Logout starts a synchronous logout process. It doesn't return
 	// until the logout operation has been completed.
 	Logout(context.Context) error
+	// SetExpirySooner sets the node's expiry time via the controlclient,
+	// as long as it's shorter than the current expiry time.
+	SetExpirySooner(context.Context, time.Time) error
 	// SetPaused pauses or unpauses the controlclient activity as much
 	// as possible, without losing its internal state, to minimize
 	// unnecessary network activity.
@@ -78,6 +83,9 @@ type Client interface {
 	// SetDNS sends the SetDNSRequest request to the control plane server,
 	// requesting a DNS record be created or updated.
 	SetDNS(context.Context, *tailcfg.SetDNSRequest) error
+	// DoNoiseRequest sends an HTTP request to the control plane
+	// over the Noise transport.
+	DoNoiseRequest(*http.Request) (*http.Response, error)
 }
 
 // UserVisibleError is an error that should be shown to users.

control/controlclient/direct.go

@@ -18,7 +18,6 @@ import (
 	"net/http"
 	"net/url"
 	"os"
-	"os/exec"
 	"reflect"
 	"runtime"
 	"strings"
@@ -27,6 +26,7 @@ import (
 	"time"
 
 	"go4.org/mem"
+	"golang.org/x/sync/singleflight"
 	"inet.af/netaddr"
 	"tailscale.com/control/controlknobs"
 	"tailscale.com/envknob"
@@ -38,6 +38,7 @@ import (
 	"tailscale.com/net/dnsfallback"
 	"tailscale.com/net/interfaces"
 	"tailscale.com/net/netns"
+	"tailscale.com/net/netutil"
 	"tailscale.com/net/tlsdial"
 	"tailscale.com/net/tshttpproxy"
 	"tailscale.com/tailcfg"
@@ -47,6 +48,7 @@ import (
 	"tailscale.com/types/opt"
 	"tailscale.com/types/persist"
 	"tailscale.com/util/clientmetric"
+	"tailscale.com/util/multierr"
 	"tailscale.com/util/systemd"
 	"tailscale.com/wgengine/monitor"
 )
@@ -67,9 +69,15 @@ type Direct struct {
 	keepSharerAndUserSplit bool
 	skipIPForwardingCheck  bool
 	pinger                 Pinger
+	popBrowser             func(url string) // or nil
+
+	mu             sync.Mutex        // mutex guards the following fields
+	serverKey      key.MachinePublic // original ("legacy") nacl crypto_box-based public key
+	serverNoiseKey key.MachinePublic
+
+	sfGroup     singleflight.Group // protects noiseClient creation.
+	noiseClient *noiseClient
 
-	mu           sync.Mutex // mutex guards the following fields
-	serverKey    key.MachinePublic
 	persist      persist.Persist
 	authKey      string
 	tryingNewKey key.NodePrivate
@@ -93,9 +101,10 @@ type Options struct {
 	NewDecompressor      func() (Decompressor, error)
 	KeepAlive            bool
 	Logf                 logger.Logf
-	HTTPTestClient       *http.Client // optional HTTP client to use (for tests only)
-	DebugFlags           []string     // debug settings to send to control
-	LinkMonitor          *monitor.Mon // optional link monitor
+	HTTPTestClient       *http.Client     // optional HTTP client to use (for tests only)
+	DebugFlags           []string         // debug settings to send to control
+	LinkMonitor          *monitor.Mon     // optional link monitor
+	PopBrowserURL        func(url string) // optional func to open browser
 
 	// KeepSharerAndUserSplit controls whether the client
 	// understands Node.Sharer. If false, the Sharer is mapped to the User.
@@ -168,6 +177,10 @@ func NewDirect(opts Options) (*Direct, error) {
 		tr.DialContext = dnscache.Dialer(dialer.DialContext, dnsCache)
 		tr.DialTLSContext = dnscache.TLSDialer(dialer.DialContext, dnsCache, tr.TLSClientConfig)
 		tr.ForceAttemptHTTP2 = true
+		// Disable implicit gzip compression; the various
+		// handlers (register, map, set-dns, etc) do their own
+		// zstd compression per naclbox.
+		tr.DisableCompression = true
 		httpc = &http.Client{Transport: tr}
 	}
 
@@ -187,6 +200,7 @@ func NewDirect(opts Options) (*Direct, error) {
 		linkMon:                opts.LinkMonitor,
 		skipIPForwardingCheck:  opts.SkipIPForwardingCheck,
 		pinger:                 opts.Pinger,
+		popBrowser:             opts.PopBrowserURL,
 	}
 	if opts.Hostinfo == nil {
 		c.SetHostinfo(hostinfo.New())
@@ -196,6 +210,19 @@ func NewDirect(opts Options) (*Direct, error) {
 	return c, nil
 }
 
+// Close closes the underlying Noise connection(s).
+func (c *Direct) Close() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.noiseClient != nil {
+		if err := c.noiseClient.Close(); err != nil {
+			return err
+		}
+	}
+	c.noiseClient = nil
+	return nil
+}
+
 // SetHostinfo clones the provided Hostinfo and remembers it for the
 // next update. It reports whether the Hostinfo has changed.
 func (c *Direct) SetHostinfo(hi *tailcfg.Hostinfo) bool {
@@ -210,7 +237,7 @@ func (c *Direct) SetHostinfo(hi *tailcfg.Hostinfo) bool {
 	}
 	c.hostinfo = hi.Clone()
 	j, _ := json.Marshal(c.hostinfo)
-	c.logf("HostInfo: %s", j)
+	c.logf("[v1] HostInfo: %s", j)
 	return true
 }
 
@@ -241,10 +268,10 @@ func (c *Direct) GetPersist() persist.Persist {
 }
 
 func (c *Direct) TryLogout(ctx context.Context) error {
-	c.logf("direct.TryLogout()")
+	c.logf("[v1] direct.TryLogout()")
 
 	mustRegen, newURL, err := c.doLogin(ctx, loginOpt{Logout: true})
-	c.logf("TryLogout control response: mustRegen=%v, newURL=%v, err=%v", mustRegen, newURL, err)
+	c.logf("[v1] TryLogout control response: mustRegen=%v, newURL=%v, err=%v", mustRegen, newURL, err)
 
 	c.mu.Lock()
 	c.persist = persist.Persist{}
@@ -254,7 +281,7 @@ func (c *Direct) TryLogout(ctx context.Context) error {
 }
 
 func (c *Direct) TryLogin(ctx context.Context, t *tailcfg.Oauth2Token, flags LoginFlags) (url string, err error) {
-	c.logf("direct.TryLogin(token=%v, flags=%v)", t != nil, flags)
+	c.logf("[v1] direct.TryLogin(token=%v, flags=%v)", t != nil, flags)
 	return c.doLoginOrRegen(ctx, loginOpt{Token: t, Flags: flags})
 }
 
@@ -262,7 +289,7 @@ func (c *Direct) TryLogin(ctx context.Context, t *tailcfg.Oauth2Token, flags Log
 //
 // On success, newURL and err will both be nil.
 func (c *Direct) WaitLoginURL(ctx context.Context, url string) (newURL string, err error) {
-	c.logf("direct.WaitLoginURL")
+	c.logf("[v1] direct.WaitLoginURL")
 	return c.doLoginOrRegen(ctx, loginOpt{URL: url})
 }
 
@@ -278,12 +305,33 @@ func (c *Direct) doLoginOrRegen(ctx context.Context, opt loginOpt) (newURL strin
 	return url, err
 }
 
+// SetExpirySooner attempts to shorten the expiry to the specified time.
+func (c *Direct) SetExpirySooner(ctx context.Context, expiry time.Time) error {
+	c.logf("[v1] direct.SetExpirySooner()")
+
+	newURL, err := c.doLoginOrRegen(ctx, loginOpt{Expiry: &expiry})
+	c.logf("[v1] SetExpirySooner control response: newURL=%v, err=%v", newURL, err)
+
+	return err
+}
+
 type loginOpt struct {
 	Token  *tailcfg.Oauth2Token
 	Flags  LoginFlags
-	Regen  bool
+	Regen  bool // generate a new nodekey, can be overridden in doLogin
 	URL    string
-	Logout bool
+	Logout bool // set the expiry to the far past, expiring the node
+	// Expiry, if non-nil, attempts to set the node expiry to the
+	// specified time and cannot be used to extend the expiry.
+	// It is ignored if Logout is set since Logout works by setting a
+	// expiry time in the far past.
+	Expiry *time.Time
+}
+
+// httpClient provides a common interface for the noiseClient and
+// the NaCl box http.Client.
+type httpClient interface {
+	Do(req *http.Request) (*http.Response, error)
 }
 
 func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, newURL string, err error) {
@@ -291,6 +339,7 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 	persist := c.persist
 	tryingNewKey := c.tryingNewKey
 	serverKey := c.serverKey
+	serverNoiseKey := c.serverNoiseKey
 	authKey := c.authKey
 	hi := c.hostinfo.Clone()
 	backendLogID := hi.BackendLogID
@@ -322,18 +371,27 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 
 	c.logf("doLogin(regen=%v, hasUrl=%v)", regen, opt.URL != "")
 	if serverKey.IsZero() {
-		var err error
-		serverKey, err = loadServerKey(ctx, c.httpc, c.serverURL)
+		keys, err := loadServerPubKeys(ctx, c.httpc, c.serverURL)
 		if err != nil {
 			return regen, opt.URL, err
 		}
 		c.logf("control server key %s from %s", serverKey.ShortString(), c.serverURL)
 
 		c.mu.Lock()
-		c.serverKey = serverKey
+		c.serverKey = keys.LegacyPublicKey
+		c.serverNoiseKey = keys.PublicKey
 		c.mu.Unlock()
-	}
+		serverKey = keys.LegacyPublicKey
+		serverNoiseKey = keys.PublicKey
 
+		// For servers supporting the Noise transport,
+		// proactively shut down our TLS TCP connection.
+		// We're not going to need it and it's nicer to the
+		// server.
+		if !serverNoiseKey.IsZero() {
+			c.httpc.CloseIdleConnections()
+		}
+	}
 	var oldNodeKey key.NodePublic
 	switch {
 	case opt.Logout:
@@ -374,6 +432,8 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 	}
 	if opt.Logout {
 		request.Expiry = time.Unix(123, 0) // far in the past
+	} else if opt.Expiry != nil {
+		request.Expiry = *opt.Expiry
 	}
 	c.logf("RegisterReq: onode=%v node=%v fup=%v",
 		request.OldNodeKey.ShortString(),
@@ -401,22 +461,32 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 		c.logf("RegisterRequest: %s", j)
 	}
 
-	bodyData, err := encode(request, serverKey, machinePrivKey)
+	// URL and httpc are protocol specific.
+	var url string
+	var httpc httpClient
+	if serverNoiseKey.IsZero() {
+		httpc = c.httpc
+		url = fmt.Sprintf("%s/machine/%s", c.serverURL, machinePrivKey.Public().UntypedHexString())
+	} else {
+		request.Version = tailcfg.CurrentCapabilityVersion
+		httpc, err = c.getNoiseClient()
+		if err != nil {
+			return regen, opt.URL, fmt.Errorf("getNoiseClient: %w", err)
+		}
+		url = fmt.Sprintf("%s/machine/register", c.serverURL)
+		url = strings.Replace(url, "http:", "https:", 1)
+	}
+	bodyData, err := encode(request, serverKey, serverNoiseKey, machinePrivKey)
 	if err != nil {
 		return regen, opt.URL, err
 	}
-	body := bytes.NewReader(bodyData)
-
-	u := fmt.Sprintf("%s/machine/%s", c.serverURL, machinePrivKey.Public().UntypedHexString())
-	req, err := http.NewRequest("POST", u, body)
+	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(bodyData))
 	if err != nil {
 		return regen, opt.URL, err
 	}
-	req = req.WithContext(ctx)
-
-	res, err := c.httpc.Do(req)
+	res, err := httpc.Do(req)
 	if err != nil {
-		return regen, opt.URL, fmt.Errorf("register request: %v", err)
+		return regen, opt.URL, fmt.Errorf("register request: %w", err)
 	}
 	if res.StatusCode != 200 {
 		msg, _ := ioutil.ReadAll(res.Body)
@@ -425,7 +495,7 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 			res.StatusCode, strings.TrimSpace(string(msg)))
 	}
 	resp := tailcfg.RegisterResponse{}
-	if err := decode(res, &resp, serverKey, machinePrivKey); err != nil {
+	if err := decode(res, &resp, serverKey, serverNoiseKey, machinePrivKey); err != nil {
 		c.logf("error decoding RegisterResponse with server key %s and machine key %s: %v", serverKey, machinePrivKey.Public(), err)
 		return regen, opt.URL, fmt.Errorf("register request: %v", err)
 	}
@@ -465,7 +535,7 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 	if resp.AuthURL != "" {
 		c.logf("AuthURL is %v", resp.AuthURL)
 	} else {
-		c.logf("No AuthURL")
+		c.logf("[v1] No AuthURL")
 	}
 
 	c.mu.Lock()
@@ -516,7 +586,7 @@ func (c *Direct) newEndpoints(localPort uint16, endpoints []tailcfg.Endpoint) (c
 	for _, ep := range endpoints {
 		epStrs = append(epStrs, ep.Addr.String())
 	}
-	c.logf("client.newEndpoints(%v, %v)", localPort, epStrs)
+	c.logf("[v2] client.newEndpoints(%v, %v)", localPort, epStrs)
 	c.localPort = localPort
 	c.endpoints = append(c.endpoints[:0], endpoints...)
 	if len(endpoints) > 0 {
@@ -572,6 +642,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 	persist := c.persist
 	serverURL := c.serverURL
 	serverKey := c.serverKey
+	serverNoiseKey := c.serverNoiseKey
 	hi := c.hostinfo.Clone()
 	backendLogID := hi.BackendLogID
 	localPort := c.localPort
@@ -610,7 +681,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 	}
 
 	request := &tailcfg.MapRequest{
-		Version:       tailcfg.CurrentMapRequestVersion,
+		Version:       tailcfg.CurrentCapabilityVersion,
 		KeepAlive:     c.keepAlive,
 		NodeKey:       persist.PrivateNodeKey.Public(),
 		DiscoKey:      c.discoPubKey,
@@ -654,7 +725,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 		request.ReadOnly = true
 	}
 
-	bodyData, err := encode(request, serverKey, machinePrivKey)
+	bodyData, err := encode(request, serverKey, serverNoiseKey, machinePrivKey)
 	if err != nil {
 		vlogf("netmap: encode: %v", err)
 		return err
@@ -665,14 +736,28 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 
 	machinePubKey := machinePrivKey.Public()
 	t0 := time.Now()
-	u := fmt.Sprintf("%s/machine/%s/map", serverURL, machinePubKey.UntypedHexString())
 
-	req, err := http.NewRequestWithContext(ctx, "POST", u, bytes.NewReader(bodyData))
+	// Url and httpc are protocol specific.
+	var url string
+	var httpc httpClient
+	if serverNoiseKey.IsZero() {
+		httpc = c.httpc
+		url = fmt.Sprintf("%s/machine/%s/map", serverURL, machinePubKey.UntypedHexString())
+	} else {
+		httpc, err = c.getNoiseClient()
+		if err != nil {
+			return fmt.Errorf("getNoiseClient: %w", err)
+		}
+		url = fmt.Sprintf("%s/machine/map", serverURL)
+		url = strings.Replace(url, "http:", "https:", 1)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(bodyData))
 	if err != nil {
 		return err
 	}
 
-	res, err := c.httpc.Do(req)
+	res, err := httpc.Do(req)
 	if err != nil {
 		vlogf("netmap: Do: %v", err)
 		return err
@@ -767,12 +852,24 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 			metricMapResponsePings.Add(1)
 			go answerPing(c.logf, c.httpc, pr)
 		}
-
+		if u := resp.PopBrowserURL; u != "" && u != sess.lastPopBrowserURL {
+			sess.lastPopBrowserURL = u
+			if c.popBrowser != nil {
+				c.logf("netmap: control says to open URL %v; opening...", u)
+				c.popBrowser(u)
+			} else {
+				c.logf("netmap: control says to open URL %v; no popBrowser func", u)
+			}
+		}
+		if resp.ControlTime != nil && !resp.ControlTime.IsZero() {
+			c.logf.JSON(1, "controltime", resp.ControlTime.UTC())
+		}
 		if resp.KeepAlive {
 			vlogf("netmap: got keep-alive")
 		} else {
 			vlogf("netmap: got new map")
 		}
+
 		select {
 		case timeoutReset <- struct{}{}:
 			vlogf("netmap: sent timer reset")
@@ -821,10 +918,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 
 		if Debug.StripEndpoints {
 			for _, p := range resp.Peers {
-				// We need at least one endpoint here for now else
-				// other code doesn't even create the discoEndpoint.
-				// TODO(bradfitz): fix that and then just nil this out.
-				p.Endpoints = []string{"127.9.9.9:456"}
+				p.Endpoints = nil
 			}
 		}
 		if Debug.StripCaps {
@@ -861,7 +955,9 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 	return nil
 }
 
-func decode(res *http.Response, v interface{}, serverKey key.MachinePublic, mkey key.MachinePrivate) error {
+// decode JSON decodes the res.Body into v. If serverNoiseKey is not specified,
+// it uses the serverKey and mkey to decode the message from the NaCl-crypto-box.
+func decode(res *http.Response, v any, serverKey, serverNoiseKey key.MachinePublic, mkey key.MachinePrivate) error {
 	defer res.Body.Close()
 	msg, err := ioutil.ReadAll(io.LimitReader(res.Body, 1<<20))
 	if err != nil {
@@ -870,6 +966,9 @@ func decode(res *http.Response, v interface{}, serverKey key.MachinePublic, mkey
 	if res.StatusCode != 200 {
 		return fmt.Errorf("%d: %v", res.StatusCode, string(msg))
 	}
+	if !serverNoiseKey.IsZero() {
+		return json.Unmarshal(msg, v)
+	}
 	return decodeMsg(msg, v, serverKey, mkey)
 }
 
@@ -880,14 +979,24 @@ var (
 
 var jsonEscapedZero = []byte(`\u0000`)
 
-func (c *Direct) decodeMsg(msg []byte, v interface{}, machinePrivKey key.MachinePrivate) error {
+// decodeMsg is responsible for uncompressing msg and unmarshaling into v.
+// If c.serverNoiseKey is not specified, it uses the c.serverKey and mkey
+// to first the decrypt msg from the NaCl-crypto-box.
+func (c *Direct) decodeMsg(msg []byte, v any, mkey key.MachinePrivate) error {
 	c.mu.Lock()
 	serverKey := c.serverKey
+	serverNoiseKey := c.serverNoiseKey
 	c.mu.Unlock()
 
-	decrypted, ok := machinePrivKey.OpenFrom(serverKey, msg)
-	if !ok {
-		return errors.New("cannot decrypt response")
+	var decrypted []byte
+	if serverNoiseKey.IsZero() {
+		var ok bool
+		decrypted, ok = mkey.OpenFrom(serverKey, msg)
+		if !ok {
+			return errors.New("cannot decrypt response")
+		}
+	} else {
+		decrypted = msg
 	}
 	var b []byte
 	if c.newDecompressor == nil {
@@ -919,7 +1028,7 @@ func (c *Direct) decodeMsg(msg []byte, v interface{}, machinePrivKey key.Machine
 
 }
 
-func decodeMsg(msg []byte, v interface{}, serverKey key.MachinePublic, machinePrivKey key.MachinePrivate) error {
+func decodeMsg(msg []byte, v any, serverKey key.MachinePublic, machinePrivKey key.MachinePrivate) error {
 	decrypted, ok := machinePrivKey.OpenFrom(serverKey, msg)
 	if !ok {
 		return errors.New("cannot decrypt response")
@@ -933,7 +1042,9 @@ func decodeMsg(msg []byte, v interface{}, serverKey key.MachinePublic, machinePr
 	return nil
 }
 
-func encode(v interface{}, serverKey key.MachinePublic, mkey key.MachinePrivate) ([]byte, error) {
+// encode JSON encodes v. If serverNoiseKey is not specified, it uses the serverKey and mkey to
+// seal the message into a NaCl-crypto-box.
+func encode(v any, serverKey, serverNoiseKey key.MachinePublic, mkey key.MachinePrivate) ([]byte, error) {
 	b, err := json.Marshal(v)
 	if err != nil {
 		return nil, err
@@ -943,32 +1054,45 @@ func encode(v interface{}, serverKey key.MachinePublic, mkey key.MachinePrivate)
 			log.Printf("MapRequest: %s", b)
 		}
 	}
+	if !serverNoiseKey.IsZero() {
+		return b, nil
+	}
 	return mkey.SealTo(serverKey, b), nil
 }
 
-func loadServerKey(ctx context.Context, httpc *http.Client, serverURL string) (key.MachinePublic, error) {
-	req, err := http.NewRequest("GET", serverURL+"/key", nil)
+func loadServerPubKeys(ctx context.Context, httpc *http.Client, serverURL string) (*tailcfg.OverTLSPublicKeyResponse, error) {
+	keyURL := fmt.Sprintf("%v/key?v=%d", serverURL, tailcfg.CurrentCapabilityVersion)
+	req, err := http.NewRequestWithContext(ctx, "GET", keyURL, nil)
 	if err != nil {
-		return key.MachinePublic{}, fmt.Errorf("create control key request: %v", err)
+		return nil, fmt.Errorf("create control key request: %v", err)
 	}
-	req = req.WithContext(ctx)
 	res, err := httpc.Do(req)
 	if err != nil {
-		return key.MachinePublic{}, fmt.Errorf("fetch control key: %v", err)
+		return nil, fmt.Errorf("fetch control key: %v", err)
 	}
 	defer res.Body.Close()
-	b, err := ioutil.ReadAll(io.LimitReader(res.Body, 1<<16))
+	b, err := ioutil.ReadAll(io.LimitReader(res.Body, 64<<10))
 	if err != nil {
-		return key.MachinePublic{}, fmt.Errorf("fetch control key response: %v", err)
+		return nil, fmt.Errorf("fetch control key response: %v", err)
 	}
 	if res.StatusCode != 200 {
-		return key.MachinePublic{}, fmt.Errorf("fetch control key: %d: %s", res.StatusCode, string(b))
+		return nil, fmt.Errorf("fetch control key: %d", res.StatusCode)
 	}
+	var out tailcfg.OverTLSPublicKeyResponse
+	jsonErr := json.Unmarshal(b, &out)
+	if jsonErr == nil {
+		return &out, nil
+	}
+
+	// Some old control servers might not be updated to send the new format.
+	// Accept the old pre-JSON format too.
+	out = tailcfg.OverTLSPublicKeyResponse{}
 	k, err := key.ParseMachinePublicUntyped(mem.B(b))
 	if err != nil {
-		return key.MachinePublic{}, fmt.Errorf("fetch control key: %v", err)
+		return nil, multierr.New(jsonErr, err)
 	}
-	return k, nil
+	out.LegacyPublicKey = k
+	return &out, nil
 }
 
 // Debug contains temporary internal-only debug knobs.
@@ -1027,89 +1151,17 @@ func TrimWGConfig() opt.Bool {
 //
 // It should not return false positives.
 //
-// TODO(bradfitz): merge this code into LocalBackend.CheckIPForwarding
-// and change controlclient.Options.SkipIPForwardingCheck into a
-// func([]netaddr.IPPrefix) error signature instead. Then we only have
-// one copy of this code.
+// TODO(bradfitz): Change controlclient.Options.SkipIPForwardingCheck into a
+// func([]netaddr.IPPrefix) error signature instead.
 func ipForwardingBroken(routes []netaddr.IPPrefix, state *interfaces.State) bool {
-	if len(routes) == 0 {
-		// Nothing to route, so no need to warn.
+	warn, err := netutil.CheckIPForwarding(routes, state)
+	if err != nil {
+		// Oh well, we tried. This is just for debugging.
+		// We don't want false positives.
+		// TODO: maybe we want a different warning for inability to check?
 		return false
 	}
-
-	if runtime.GOOS != "linux" {
-		// We only do subnet routing on Linux for now.
-		// It might work on darwin/macOS when building from source, so
-		// don't return true for other OSes. We can OS-based warnings
-		// already in the admin panel.
-		return false
-	}
-
-	localIPs := map[netaddr.IP]bool{}
-	for _, addrs := range state.InterfaceIPs {
-		for _, pfx := range addrs {
-			localIPs[pfx.IP()] = true
-		}
-	}
-
-	v4Routes, v6Routes := false, false
-	for _, r := range routes {
-		// It's possible to advertise a route to one of the local
-		// machine's local IPs. IP forwarding isn't required for this
-		// to work, so we shouldn't warn for such exports.
-		if r.IsSingleIP() && localIPs[r.IP()] {
-			continue
-		}
-		if r.IP().Is4() {
-			v4Routes = true
-		} else {
-			v6Routes = true
-		}
-	}
-
-	if v4Routes {
-		out, err := ioutil.ReadFile("/proc/sys/net/ipv4/ip_forward")
-		if err != nil {
-			// Try another way.
-			out, err = exec.Command("sysctl", "-n", "net.ipv4.ip_forward").Output()
-		}
-		if err != nil {
-			// Oh well, we tried. This is just for debugging.
-			// We don't want false positives.
-			// TODO: maybe we want a different warning for inability to check?
-			return false
-		}
-		if strings.TrimSpace(string(out)) == "0" {
-			return true
-		}
-	}
-	if v6Routes {
-		// Note: you might be wondering why we check only the state of
-		// conf.all.forwarding, rather than per-interface forwarding
-		// configuration. According to kernel documentation, it seems
-		// that to actually forward packets, you need to enable
-		// forwarding globally, and the per-interface forwarding
-		// setting only alters other things such as how router
-		// advertisements are handled. The kernel itself warns that
-		// enabling forwarding per-interface and not globally will
-		// probably not work, so I feel okay calling those configs
-		// broken until we have proof otherwise.
-		out, err := ioutil.ReadFile("/proc/sys/net/ipv6/conf/all/forwarding")
-		if err != nil {
-			out, err = exec.Command("sysctl", "-n", "net.ipv6.conf.all.forwarding").Output()
-		}
-		if err != nil {
-			// Oh well, we tried. This is just for debugging.
-			// We don't want false positives.
-			// TODO: maybe we want a different warning for inability to check?
-			return false
-		}
-		if strings.TrimSpace(string(out)) == "0" {
-			return true
-		}
-	}
-
-	return false
+	return warn != nil
 }
 
 // isUniquePingRequest reports whether pr contains a new PingRequest.URL
@@ -1186,6 +1238,78 @@ func sleepAsRequested(ctx context.Context, logf logger.Logf, timeoutReset chan<-
 	}
 }
 
+// getNoiseClient returns the noise client, creating one if one doesn't exist.
+func (c *Direct) getNoiseClient() (*noiseClient, error) {
+	c.mu.Lock()
+	serverNoiseKey := c.serverNoiseKey
+	nc := c.noiseClient
+	c.mu.Unlock()
+	if serverNoiseKey.IsZero() {
+		return nil, errors.New("zero serverNoiseKey")
+	}
+	if nc != nil {
+		return nc, nil
+	}
+	np, err, _ := c.sfGroup.Do("noise", func() (any, error) {
+		k, err := c.getMachinePrivKey()
+		if err != nil {
+			return nil, err
+		}
+
+		nc, err = newNoiseClient(k, serverNoiseKey, c.serverURL)
+		if err != nil {
+			return nil, err
+		}
+		c.mu.Lock()
+		defer c.mu.Unlock()
+		c.noiseClient = nc
+		return nc, nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return np.(*noiseClient), nil
+}
+
+// setDNSNoise sends the SetDNSRequest request to the control plane server over Noise,
+// requesting a DNS record be created or updated.
+func (c *Direct) setDNSNoise(ctx context.Context, req *tailcfg.SetDNSRequest) error {
+	newReq := *req
+	newReq.Version = tailcfg.CurrentCapabilityVersion
+	np, err := c.getNoiseClient()
+	if err != nil {
+		return err
+	}
+	bodyData, err := json.Marshal(newReq)
+	if err != nil {
+		return err
+	}
+	res, err := np.Post(fmt.Sprintf("https://%v/%v", np.serverHost, "machine/set-dns"), "application/json", bytes.NewReader(bodyData))
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+	if res.StatusCode != 200 {
+		msg, _ := ioutil.ReadAll(res.Body)
+		return fmt.Errorf("set-dns response: %v, %.200s", res.Status, strings.TrimSpace(string(msg)))
+	}
+	var setDNSRes tailcfg.SetDNSResponse
+	if err := json.NewDecoder(res.Body).Decode(&setDNSRes); err != nil {
+		c.logf("error decoding SetDNSResponse: %v", err)
+		return fmt.Errorf("set-dns-response: %w", err)
+	}
+
+	return nil
+}
+
+// noiseConfigured reports whether the client can communicate with Control
+// over Noise.
+func (c *Direct) noiseConfigured() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return !c.serverNoiseKey.IsZero()
+}
+
 // SetDNS sends the SetDNSRequest request to the control plane server,
 // requesting a DNS record be created or updated.
 func (c *Direct) SetDNS(ctx context.Context, req *tailcfg.SetDNSRequest) (err error) {
@@ -1195,6 +1319,9 @@ func (c *Direct) SetDNS(ctx context.Context, req *tailcfg.SetDNSRequest) (err er
 			metricSetDNSError.Add(1)
 		}
 	}()
+	if c.noiseConfigured() {
+		return c.setDNSNoise(ctx, req)
+	}
 	c.mu.Lock()
 	serverKey := c.serverKey
 	c.mu.Unlock()
@@ -1210,7 +1337,9 @@ func (c *Direct) SetDNS(ctx context.Context, req *tailcfg.SetDNSRequest) (err er
 		return errors.New("getMachinePrivKey returned zero key")
 	}
 
-	bodyData, err := encode(req, serverKey, machinePrivKey)
+	// TODO(maisem): dedupe this codepath from SetDNSNoise.
+	var serverNoiseKey key.MachinePublic
+	bodyData, err := encode(req, serverKey, serverNoiseKey, machinePrivKey)
 	if err != nil {
 		return err
 	}
@@ -1230,15 +1359,23 @@ func (c *Direct) SetDNS(ctx context.Context, req *tailcfg.SetDNSRequest) (err er
 		msg, _ := ioutil.ReadAll(res.Body)
 		return fmt.Errorf("set-dns response: %v, %.200s", res.Status, strings.TrimSpace(string(msg)))
 	}
-	var setDNSRes struct{} // no fields yet
-	if err := decode(res, &setDNSRes, serverKey, machinePrivKey); err != nil {
+	var setDNSRes tailcfg.SetDNSResponse
+	if err := decode(res, &setDNSRes, serverKey, serverNoiseKey, machinePrivKey); err != nil {
 		c.logf("error decoding SetDNSResponse with server key %s and machine key %s: %v", serverKey, machinePrivKey.Public(), err)
-		return fmt.Errorf("set-dns-response: %v", err)
+		return fmt.Errorf("set-dns-response: %w", err)
 	}
 
 	return nil
 }
 
+func (c *Direct) DoNoiseRequest(req *http.Request) (*http.Response, error) {
+	nc, err := c.getNoiseClient()
+	if err != nil {
+		return nil, err
+	}
+	return nc.Do(req)
+}
+
 // tsmpPing sends a Ping to pr.IP, and sends an http request back to pr.URL
 // with ping response data.
 func tsmpPing(logf logger.Logf, c *http.Client, pr *tailcfg.PingRequest, pinger Pinger) error {

control/controlclient/map.go

@@ -39,10 +39,12 @@ type mapSession struct {
 	lastDERPMap            *tailcfg.DERPMap
 	lastUserProfile        map[tailcfg.UserID]tailcfg.UserProfile
 	lastParsedPacketFilter []filter.Match
+	lastSSHPolicy          *tailcfg.SSHPolicy
 	collectServices        bool
 	previousPeers          []*tailcfg.Node // for delta-purposes
 	lastDomain             string
 	lastHealth             []string
+	lastPopBrowserURL      string
 
 	// netMapBuilding is non-nil during a netmapForResponse call,
 	// containing the value to be returned, once fully populated.
@@ -97,6 +99,9 @@ func (ms *mapSession) netmapForResponse(resp *tailcfg.MapResponse) *netmap.Netwo
 	if c := resp.DNSConfig; c != nil {
 		ms.lastDNSConfig = c
 	}
+	if p := resp.SSHPolicy; p != nil {
+		ms.lastSSHPolicy = p
+	}
 
 	if v, ok := resp.CollectServices.Get(); ok {
 		ms.collectServices = v
@@ -117,6 +122,7 @@ func (ms *mapSession) netmapForResponse(resp *tailcfg.MapResponse) *netmap.Netwo
 		Domain:          ms.lastDomain,
 		DNS:             *ms.lastDNSConfig,
 		PacketFilter:    ms.lastParsedPacketFilter,
+		SSHPolicy:       ms.lastSSHPolicy,
 		CollectServices: ms.collectServices,
 		DERPMap:         ms.lastDERPMap,
 		Debug:           resp.Debug,
@@ -133,7 +139,9 @@ func (ms *mapSession) netmapForResponse(resp *tailcfg.MapResponse) *netmap.Netwo
 		nm.Name = node.Name
 		nm.Addresses = filterSelfAddresses(node.Addresses)
 		nm.User = node.User
-		nm.Hostinfo = node.Hostinfo
+		if node.Hostinfo.Valid() {
+			nm.Hostinfo = *node.Hostinfo.AsStruct()
+		}
 		if node.MachineAuthorized {
 			nm.MachineStatus = tailcfg.MachineAuthorized
 		} else {

control/controlclient/noise.go

@@ -0,0 +1,166 @@
+// 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 controlclient
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"math"
+	"net"
+	"net/http"
+	"net/url"
+	"sync"
+	"time"
+
+	"golang.org/x/net/http2"
+	"tailscale.com/control/controlbase"
+	"tailscale.com/control/controlhttp"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/key"
+	"tailscale.com/util/multierr"
+)
+
+// noiseConn is a wrapper around controlbase.Conn.
+// It allows attaching an ID to a connection to allow
+// cleaning up references in the pool when the connection
+// is closed.
+type noiseConn struct {
+	*controlbase.Conn
+	id   int
+	pool *noiseClient
+}
+
+func (c *noiseConn) Close() error {
+	if err := c.Conn.Close(); err != nil {
+		return err
+	}
+	c.pool.connClosed(c.id)
+	return nil
+}
+
+// noiseClient provides a http.Client to connect to tailcontrol over
+// the ts2021 protocol.
+type noiseClient struct {
+	*http.Client // HTTP client used to talk to tailcontrol
+	privKey      key.MachinePrivate
+	serverPubKey key.MachinePublic
+	serverHost   string // the host:port part of serverURL
+
+	// mu only protects the following variables.
+	mu       sync.Mutex
+	nextID   int
+	connPool map[int]*noiseConn // active connections not yet closed; see noiseConn.Close
+}
+
+// newNoiseClient returns a new noiseClient for the provided server and machine key.
+// serverURL is of the form https://<host>:<port> (no trailing slash).
+func newNoiseClient(priKey key.MachinePrivate, serverPubKey key.MachinePublic, serverURL string) (*noiseClient, error) {
+	u, err := url.Parse(serverURL)
+	if err != nil {
+		return nil, err
+	}
+	var host string
+	if u.Port() != "" {
+		// If there is an explicit port specified use it.
+		host = u.Host
+	} else {
+		// Otherwise, controlhttp.Dial expects an http endpoint.
+		host = fmt.Sprintf("%v:80", u.Hostname())
+	}
+	np := &noiseClient{
+		serverPubKey: serverPubKey,
+		privKey:      priKey,
+		serverHost:   host,
+	}
+
+	// Create the HTTP/2 Transport using a net/http.Transport
+	// (which only does HTTP/1) because it's the only way to
+	// configure certain properties on the http2.Transport. But we
+	// never actually use the net/http.Transport for any HTTP/1
+	// requests.
+	h2Transport, err := http2.ConfigureTransports(&http.Transport{
+		IdleConnTimeout: time.Minute,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	// Let the HTTP/2 Transport think it's dialing out using TLS,
+	// but it's actually our Noise dialer:
+	h2Transport.DialTLS = np.dial
+
+	// ConfigureTransports assumes it's being used to wire up an HTTP/1
+	// and HTTP/2 Transport together, so its returned http2.Transport
+	// has a ConnPool already initialized that's configured to not dial
+	// (assuming it's only called from the HTTP/1 Transport). But we
+	// want it to dial, so nil it out before use. On first use it has
+	// a sync.Once that lazily initializes the ConnPool to its default
+	// one that dials.
+	h2Transport.ConnPool = nil
+
+	np.Client = &http.Client{Transport: h2Transport}
+	return np, nil
+}
+
+// connClosed removes the connection with the provided ID from the pool
+// of active connections.
+func (nc *noiseClient) connClosed(id int) {
+	nc.mu.Lock()
+	defer nc.mu.Unlock()
+	delete(nc.connPool, id)
+}
+
+// Close closes all the underlying noise connections.
+// It is a no-op and returns nil if the connection is already closed.
+func (nc *noiseClient) Close() error {
+	nc.mu.Lock()
+	conns := nc.connPool
+	nc.connPool = nil
+	nc.mu.Unlock()
+
+	var errors []error
+	for _, c := range conns {
+		if err := c.Close(); err != nil {
+			errors = append(errors, err)
+		}
+	}
+	return multierr.New(errors...)
+}
+
+// dial opens a new connection to tailcontrol, fetching the server noise key
+// if not cached. It implements the signature needed by http2.Transport.DialTLS
+// but ignores all params as it only dials out to the server the noiseClient was
+// created for.
+func (nc *noiseClient) dial(_, _ string, _ *tls.Config) (net.Conn, error) {
+	nc.mu.Lock()
+	connID := nc.nextID
+	if nc.connPool == nil {
+		nc.connPool = make(map[int]*noiseConn)
+	}
+	nc.nextID++
+	nc.mu.Unlock()
+
+	// Timeout is a little arbitrary, but plenty long enough for even the
+	// highest latency links.
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	if tailcfg.CurrentCapabilityVersion > math.MaxUint16 {
+		// Panic, because a test should have started failing several
+		// thousand version numbers before getting to this point.
+		panic("capability version is too high to fit in the wire protocol")
+	}
+	conn, err := controlhttp.Dial(ctx, nc.serverHost, nc.privKey, nc.serverPubKey, uint16(tailcfg.CurrentCapabilityVersion))
+	if err != nil {
+		return nil, err
+	}
+
+	nc.mu.Lock()
+	defer nc.mu.Unlock()
+	ncc := &noiseConn{Conn: conn, id: connID, pool: nc}
+	nc.connPool[ncc.id] = ncc
+	return ncc, nil
+}

control/controlclient/noise_test.go

@@ -0,0 +1,28 @@
+// 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 controlclient
+
+import (
+	"math"
+	"testing"
+
+	"tailscale.com/tailcfg"
+)
+
+// maxAllowedNoiseVersion is the highest we expect the Tailscale
+// capability version to ever get. It's a value close to 2^16, but
+// with enough leeway that we get a very early warning that it's time
+// to rework the wire protocol to allow larger versions, while still
+// giving us headroom to bump this test and fix the build.
+//
+// Code elsewhere in the client will panic() if the tailcfg capability
+// version exceeds 16 bits, so take a failure of this test seriously.
+const maxAllowedNoiseVersion = math.MaxUint16 - 5000
+
+func TestNoiseVersion(t *testing.T) {
+	if tailcfg.CurrentCapabilityVersion > maxAllowedNoiseVersion {
+		t.Fatalf("tailcfg.CurrentCapabilityVersion is %d, want <=%d", tailcfg.CurrentCapabilityVersion, maxAllowedNoiseVersion)
+	}
+}

control/controlclient/sign_supported.go

@@ -18,6 +18,7 @@ import (
 	"errors"
 	"fmt"
 	"sync"
+	"time"
 
 	"github.com/tailscale/certstore"
 	"tailscale.com/tailcfg"
@@ -73,23 +74,46 @@ func isSubjectInChain(subject string, chain []*x509.Certificate) bool {
 	return false
 }
 
-func selectIdentityFromSlice(subject string, ids []certstore.Identity) (certstore.Identity, []*x509.Certificate) {
+func selectIdentityFromSlice(subject string, ids []certstore.Identity, now time.Time) (certstore.Identity, []*x509.Certificate) {
+	var bestCandidate struct {
+		id    certstore.Identity
+		chain []*x509.Certificate
+	}
+
 	for _, id := range ids {
 		chain, err := id.CertificateChain()
 		if err != nil {
 			continue
 		}
 
+		if len(chain) < 1 {
+			continue
+		}
+
 		if !isSupportedCertificate(chain[0]) {
 			continue
 		}
 
-		if isSubjectInChain(subject, chain) {
-			return id, chain
+		if now.Before(chain[0].NotBefore) || now.After(chain[0].NotAfter) {
+			// Certificate is not valid at this time
+			continue
 		}
+
+		if !isSubjectInChain(subject, chain) {
+			continue
+		}
+
+		// Select the most recently issued certificate. If there is a tie, pick
+		// one arbitrarily.
+		if len(bestCandidate.chain) > 0 && bestCandidate.chain[0].NotBefore.After(chain[0].NotBefore) {
+			continue
+		}
+
+		bestCandidate.id = id
+		bestCandidate.chain = chain
 	}
 
-	return nil, nil
+	return bestCandidate.id, bestCandidate.chain
 }
 
 // findIdentity locates an identity from the Windows or Darwin certificate
@@ -105,7 +129,7 @@ func findIdentity(subject string, st certstore.Store) (certstore.Identity, []*x5
 		return nil, nil, err
 	}
 
-	selected, chain := selectIdentityFromSlice(subject, ids)
+	selected, chain := selectIdentityFromSlice(subject, ids, time.Now())
 
 	for _, id := range ids {
 		if id != selected {

control/controlclient/sign_supported_test.go

@@ -0,0 +1,238 @@
+// 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 && cgo
+// +build windows,cgo
+
+package controlclient
+
+import (
+	"crypto"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"errors"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/tailscale/certstore"
+)
+
+const (
+	testRootCommonName = "testroot"
+	testRootSubject    = "CN=testroot"
+)
+
+type testIdentity struct {
+	chain []*x509.Certificate
+}
+
+func makeChain(rootCommonName string, notBefore, notAfter time.Time) []*x509.Certificate {
+	return []*x509.Certificate{
+		{
+			NotBefore:          notBefore,
+			NotAfter:           notAfter,
+			PublicKeyAlgorithm: x509.RSA,
+		},
+		{
+			Subject: pkix.Name{
+				CommonName: rootCommonName,
+			},
+			PublicKeyAlgorithm: x509.RSA,
+		},
+	}
+}
+
+func (t *testIdentity) Certificate() (*x509.Certificate, error) {
+	return t.chain[0], nil
+}
+
+func (t *testIdentity) CertificateChain() ([]*x509.Certificate, error) {
+	return t.chain, nil
+}
+
+func (t *testIdentity) Signer() (crypto.Signer, error) {
+	return nil, errors.New("not implemented")
+}
+
+func (t *testIdentity) Delete() error {
+	return errors.New("not implemented")
+}
+
+func (t *testIdentity) Close() {}
+
+func TestSelectIdentityFromSlice(t *testing.T) {
+	var times []time.Time
+	for _, ts := range []string{
+		"2000-01-01T00:00:00Z",
+		"2001-01-01T00:00:00Z",
+		"2002-01-01T00:00:00Z",
+		"2003-01-01T00:00:00Z",
+	} {
+		tm, err := time.Parse(time.RFC3339, ts)
+		if err != nil {
+			t.Fatal(err)
+		}
+		times = append(times, tm)
+	}
+
+	tests := []struct {
+		name    string
+		subject string
+		ids     []certstore.Identity
+		now     time.Time
+		// wantIndex is an index into ids, or -1 for nil.
+		wantIndex int
+	}{
+		{
+			name:    "single unexpired identity",
+			subject: testRootSubject,
+			ids: []certstore.Identity{
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[0], times[2]),
+				},
+			},
+			now:       times[1],
+			wantIndex: 0,
+		},
+		{
+			name:    "single expired identity",
+			subject: testRootSubject,
+			ids: []certstore.Identity{
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[0], times[1]),
+				},
+			},
+			now:       times[2],
+			wantIndex: -1,
+		},
+		{
+			name:    "unrelated ids",
+			subject: testRootSubject,
+			ids: []certstore.Identity{
+				&testIdentity{
+					chain: makeChain("something", times[0], times[2]),
+				},
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[0], times[2]),
+				},
+				&testIdentity{
+					chain: makeChain("else", times[0], times[2]),
+				},
+			},
+			now:       times[1],
+			wantIndex: 1,
+		},
+		{
+			name:    "expired with unrelated ids",
+			subject: testRootSubject,
+			ids: []certstore.Identity{
+				&testIdentity{
+					chain: makeChain("something", times[0], times[3]),
+				},
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[0], times[1]),
+				},
+				&testIdentity{
+					chain: makeChain("else", times[0], times[3]),
+				},
+			},
+			now:       times[2],
+			wantIndex: -1,
+		},
+		{
+			name:    "one expired",
+			subject: testRootSubject,
+			ids: []certstore.Identity{
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[0], times[1]),
+				},
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[1], times[3]),
+				},
+			},
+			now:       times[2],
+			wantIndex: 1,
+		},
+		{
+			name:    "two certs both unexpired",
+			subject: testRootSubject,
+			ids: []certstore.Identity{
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[0], times[3]),
+				},
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[1], times[3]),
+				},
+			},
+			now:       times[2],
+			wantIndex: 1,
+		},
+		{
+			name:    "two unexpired one expired",
+			subject: testRootSubject,
+			ids: []certstore.Identity{
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[0], times[3]),
+				},
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[1], times[3]),
+				},
+				&testIdentity{
+					chain: makeChain(testRootCommonName, times[0], times[1]),
+				},
+			},
+			now:       times[2],
+			wantIndex: 1,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotId, gotChain := selectIdentityFromSlice(tt.subject, tt.ids, tt.now)
+
+			if gotId == nil && gotChain != nil {
+				t.Error("id is nil: got non-nil chain, want nil chain")
+				return
+			}
+			if gotId != nil && gotChain == nil {
+				t.Error("id is not nil: got nil chain, want non-nil chain")
+				return
+			}
+			if tt.wantIndex == -1 {
+				if gotId != nil {
+					t.Error("got non-nil id, want nil id")
+				}
+				return
+			}
+			if gotId == nil {
+				t.Error("got nil id, want non-nil id")
+				return
+			}
+			if gotId != tt.ids[tt.wantIndex] {
+				found := -1
+				for i := range tt.ids {
+					if tt.ids[i] == gotId {
+						found = i
+						break
+					}
+				}
+				if found == -1 {
+					t.Errorf("got unknown id, want id at index %v", tt.wantIndex)
+				} else {
+					t.Errorf("got id at index %v, want id at index %v", found, tt.wantIndex)
+				}
+			}
+
+			tid, ok := tt.ids[tt.wantIndex].(*testIdentity)
+			if !ok {
+				t.Error("got non-testIdentity, want testIdentity")
+				return
+			}
+
+			if !reflect.DeepEqual(tid.chain, gotChain) {
+				t.Errorf("got unknown chain, want chain from id at index %v", tt.wantIndex)
+			}
+		})
+	}
+}

control/controlhttp/client.go

@@ -35,16 +35,25 @@ import (
 	"tailscale.com/net/dnscache"
 	"tailscale.com/net/dnsfallback"
 	"tailscale.com/net/netns"
+	"tailscale.com/net/netutil"
 	"tailscale.com/net/tlsdial"
 	"tailscale.com/net/tshttpproxy"
 	"tailscale.com/types/key"
 )
 
-// upgradeHeader is the value of the Upgrade HTTP header used to
-// indicate the Tailscale control protocol.
 const (
-	upgradeHeaderValue  = "tailscale-control-protocol"
+	// upgradeHeader is the value of the Upgrade HTTP header used to
+	// indicate the Tailscale control protocol.
+	upgradeHeaderValue = "tailscale-control-protocol"
+
+	// handshakeHeaderName is the HTTP request header that can
+	// optionally contain base64-encoded initial handshake
+	// payload, to save an RTT.
 	handshakeHeaderName = "X-Tailscale-Handshake"
+
+	// serverUpgradePath is where the server-side HTTP handler to
+	// to do the protocol switch is located.
+	serverUpgradePath = "/ts2021"
 )
 
 // Dial connects to the HTTP server at addr, requests to switch to the
@@ -53,7 +62,10 @@ const (
 //
 // If Dial fails to connect using addr, it also tries to tunnel over
 // TLS to <addr's host>:443 as a compatibility fallback.
-func Dial(ctx context.Context, addr string, machineKey key.MachinePrivate, controlKey key.MachinePublic) (*controlbase.Conn, error) {
+//
+// The provided ctx is only used for the initial connection, until
+// Dial returns. It does not affect the connection once established.
+func Dial(ctx context.Context, addr string, machineKey key.MachinePrivate, controlKey key.MachinePublic, protocolVersion uint16) (*controlbase.Conn, error) {
 	host, port, err := net.SplitHostPort(addr)
 	if err != nil {
 		return nil, err
@@ -65,6 +77,7 @@ func Dial(ctx context.Context, addr string, machineKey key.MachinePrivate, contr
 		httpsPort:  "443",
 		machineKey: machineKey,
 		controlKey: controlKey,
+		version:    protocolVersion,
 		proxyFunc:  tshttpproxy.ProxyFromEnvironment,
 	}
 	return a.dial()
@@ -77,6 +90,7 @@ type dialParams struct {
 	httpsPort  string
 	machineKey key.MachinePrivate
 	controlKey key.MachinePublic
+	version    uint16
 	proxyFunc  func(*http.Request) (*url.URL, error) // or nil
 
 	// For tests only
@@ -84,7 +98,7 @@ type dialParams struct {
 }
 
 func (a *dialParams) dial() (*controlbase.Conn, error) {
-	init, cont, err := controlbase.ClientDeferred(a.machineKey, a.controlKey)
+	init, cont, err := controlbase.ClientDeferred(a.machineKey, a.controlKey, a.version)
 	if err != nil {
 		return nil, err
 	}
@@ -92,7 +106,7 @@ func (a *dialParams) dial() (*controlbase.Conn, error) {
 	u := &url.URL{
 		Scheme: "http",
 		Host:   net.JoinHostPort(a.host, a.httpPort),
-		Path:   "/switch",
+		Path:   serverUpgradePath,
 	}
 	conn, httpErr := a.tryURL(u, init)
 	if httpErr == nil {
@@ -108,7 +122,7 @@ func (a *dialParams) dial() (*controlbase.Conn, error) {
 	// being difficult and see if we can get through over HTTPS.
 	u.Scheme = "https"
 	u.Host = net.JoinHostPort(a.host, a.httpsPort)
-	init, cont, err = controlbase.ClientDeferred(a.machineKey, a.controlKey)
+	init, cont, err = controlbase.ClientDeferred(a.machineKey, a.controlKey, a.version)
 	if err != nil {
 		return nil, err
 	}
@@ -221,22 +235,5 @@ func (a *dialParams) tryURL(u *url.URL, init []byte) (net.Conn, error) {
 		return nil, errors.New("http Transport did not provide a writable body")
 	}
 
-	return &wrappedConn{switchedConn, rwc}, nil
-}
-
-type wrappedConn struct {
-	net.Conn
-	rwc io.ReadWriteCloser
-}
-
-func (w *wrappedConn) Read(bs []byte) (int, error) {
-	return w.rwc.Read(bs)
-}
-
-func (w *wrappedConn) Write(bs []byte) (int, error) {
-	return w.rwc.Write(bs)
-}
-
-func (w *wrappedConn) Close() error {
-	return w.rwc.Close()
+	return netutil.NewAltReadWriteCloserConn(rwc, switchedConn), nil
 }

control/controlhttp/http_test.go

@@ -104,6 +104,7 @@ func TestControlHTTP(t *testing.T) {
 func testControlHTTP(t *testing.T, proxy proxy) {
 	client, server := key.NewMachine(), key.NewMachine()
 
+	const testProtocolVersion = 1
 	sch := make(chan serverResult, 1)
 	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		conn, err := AcceptHTTP(context.Background(), w, r, server)
@@ -152,6 +153,7 @@ func testControlHTTP(t *testing.T, proxy proxy) {
 		httpsPort:   strconv.Itoa(httpsLn.Addr().(*net.TCPAddr).Port),
 		machineKey:  client,
 		controlKey:  server.Public(),
+		version:     testProtocolVersion,
 		insecureTLS: true,
 	}
 

control/controlhttp/server.go

@@ -5,15 +5,14 @@
 package controlhttp
 
 import (
-	"bufio"
 	"context"
 	"encoding/base64"
 	"errors"
 	"fmt"
-	"net"
 	"net/http"
 
 	"tailscale.com/control/controlbase"
+	"tailscale.com/net/netutil"
 	"tailscale.com/types/key"
 )
 
@@ -62,9 +61,7 @@ func AcceptHTTP(ctx context.Context, w http.ResponseWriter, r *http.Request, pri
 		conn.Close()
 		return nil, fmt.Errorf("flushing hijacked HTTP buffer: %w", err)
 	}
-	if brw.Reader.Buffered() > 0 {
-		conn = &drainBufConn{conn, brw.Reader}
-	}
+	conn = netutil.NewDrainBufConn(conn, brw.Reader)
 
 	nc, err := controlbase.Server(ctx, conn, private, init)
 	if err != nil {
@@ -74,22 +71,3 @@ func AcceptHTTP(ctx context.Context, w http.ResponseWriter, r *http.Request, pri
 
 	return nc, nil
 }
-
-// drainBufConn is a net.Conn with an initial bunch of bytes in a
-// bufio.Reader. Read drains the bufio.Reader until empty, then passes
-// through subsequent reads to the Conn directly.
-type drainBufConn struct {
-	net.Conn
-	r *bufio.Reader
-}
-
-func (b *drainBufConn) Read(bs []byte) (int, error) {
-	if b.r == nil {
-		return b.Conn.Read(bs)
-	}
-	n, err := b.r.Read(bs)
-	if b.r.Buffered() == 0 {
-		b.r = nil
-	}
-	return n, err
-}

derp/derp_server.go

@@ -391,6 +391,18 @@ func (s *Server) isClosed() bool {
 	return s.closed
 }
 
+// IsClientConnectedForTest reports whether the client with specified key is connected.
+// This is used in tests to verify that nodes are connected.
+func (s *Server) IsClientConnectedForTest(k key.NodePublic) bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	x, ok := s.clients[k]
+	if !ok {
+		return false
+	}
+	return x.ActiveClient() != nil
+}
+
 // Accept adds a new connection to the server and serves it.
 //
 // The provided bufio ReadWriter must be already connected to nc.
@@ -453,6 +465,9 @@ func (s *Server) initMetacert() {
 		// Windows requires NotAfter and NotBefore set:
 		NotAfter:  time.Now().Add(30 * 24 * time.Hour),
 		NotBefore: time.Now().Add(-30 * 24 * time.Hour),
+		// Per https://github.com/golang/go/issues/51759#issuecomment-1071147836,
+		// macOS requires BasicConstraints when subject == issuer:
+		BasicConstraintsValid: true,
 	}
 	cert, err := x509.CreateCertificate(crand.Reader, tmpl, tmpl, pub, priv)
 	if err != nil {
@@ -1641,8 +1656,8 @@ func (m multiForwarder) ForwardPacket(src, dst key.NodePublic, payload []byte) e
 	return fwd.ForwardPacket(src, dst, payload)
 }
 
-func (s *Server) expVarFunc(f func() interface{}) expvar.Func {
-	return expvar.Func(func() interface{} {
+func (s *Server) expVarFunc(f func() any) expvar.Func {
+	return expvar.Func(func() any {
 		s.mu.Lock()
 		defer s.mu.Unlock()
 		return f()
@@ -1652,14 +1667,14 @@ func (s *Server) expVarFunc(f func() interface{}) expvar.Func {
 // ExpVar returns an expvar variable suitable for registering with expvar.Publish.
 func (s *Server) ExpVar() expvar.Var {
 	m := new(metrics.Set)
-	m.Set("gauge_memstats_sys0", expvar.Func(func() interface{} { return int64(s.memSys0) }))
-	m.Set("gauge_watchers", s.expVarFunc(func() interface{} { return len(s.watchers) }))
-	m.Set("gauge_current_file_descriptors", expvar.Func(func() interface{} { return metrics.CurrentFDs() }))
+	m.Set("gauge_memstats_sys0", expvar.Func(func() any { return int64(s.memSys0) }))
+	m.Set("gauge_watchers", s.expVarFunc(func() any { return len(s.watchers) }))
+	m.Set("gauge_current_file_descriptors", expvar.Func(func() any { return metrics.CurrentFDs() }))
 	m.Set("gauge_current_connections", &s.curClients)
 	m.Set("gauge_current_home_connections", &s.curHomeClients)
-	m.Set("gauge_clients_total", expvar.Func(func() interface{} { return len(s.clientsMesh) }))
-	m.Set("gauge_clients_local", expvar.Func(func() interface{} { return len(s.clients) }))
-	m.Set("gauge_clients_remote", expvar.Func(func() interface{} { return len(s.clientsMesh) - len(s.clients) }))
+	m.Set("gauge_clients_total", expvar.Func(func() any { return len(s.clientsMesh) }))
+	m.Set("gauge_clients_local", expvar.Func(func() any { return len(s.clients) }))
+	m.Set("gauge_clients_remote", expvar.Func(func() any { return len(s.clientsMesh) - len(s.clients) }))
 	m.Set("gauge_current_dup_client_keys", &s.dupClientKeys)
 	m.Set("gauge_current_dup_client_conns", &s.dupClientConns)
 	m.Set("counter_total_dup_client_conns", &s.dupClientConnTotal)
@@ -1683,7 +1698,7 @@ func (s *Server) ExpVar() expvar.Var {
 	m.Set("multiforwarder_created", &s.multiForwarderCreated)
 	m.Set("multiforwarder_deleted", &s.multiForwarderDeleted)
 	m.Set("packet_forwarder_delete_other_value", &s.removePktForwardOther)
-	m.Set("average_queue_duration_ms", expvar.Func(func() interface{} {
+	m.Set("average_queue_duration_ms", expvar.Func(func() any {
 		return math.Float64frombits(atomic.LoadUint64(s.avgQueueDuration))
 	}))
 	var expvarVersion expvar.String
@@ -1813,7 +1828,7 @@ func (s *Server) ServeDebugTraffic(w http.ResponseWriter, r *http.Request) {
 }
 
 var bufioWriterPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return bufio.NewWriterSize(ioutil.Discard, 2<<10)
 	},
 }

derp/derp_test.go

@@ -9,6 +9,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/x509"
+	"encoding/asn1"
 	"encoding/json"
 	"errors"
 	"expvar"
@@ -790,6 +791,17 @@ func TestMetaCert(t *testing.T) {
 	if g, w := cert.Subject.CommonName, fmt.Sprintf("derpkey%s", pub.UntypedHexString()); g != w {
 		t.Errorf("CommonName = %q; want %q", g, w)
 	}
+	if n := len(cert.Extensions); n != 1 {
+		t.Fatalf("got %d extensions; want 1", n)
+	}
+
+	// oidExtensionBasicConstraints is the Basic Constraints ID copied
+	// from the x509 package.
+	oidExtensionBasicConstraints := asn1.ObjectIdentifier{2, 5, 29, 19}
+
+	if id := cert.Extensions[0].Id; !id.Equal(oidExtensionBasicConstraints) {
+		t.Errorf("extension ID = %v; want %v", id, oidExtensionBasicConstraints)
+	}
 }
 
 type dummyNetConn struct {
@@ -802,7 +814,7 @@ func TestClientRecv(t *testing.T) {
 	tests := []struct {
 		name  string
 		input []byte
-		want  interface{}
+		want  any
 	}{
 		{
 			name: "ping",

envknob/envknob.go

@@ -20,15 +20,51 @@ import (
 	"log"
 	"os"
 	"strconv"
+	"sync"
 
 	"tailscale.com/types/opt"
 )
 
+var (
+	mu   sync.Mutex
+	set  = map[string]string{}
+	list []string
+)
+
+func noteEnv(k, v string) {
+	if v == "" {
+		return
+	}
+	mu.Lock()
+	defer mu.Unlock()
+	if _, ok := set[k]; !ok {
+		list = append(list, k)
+	}
+	set[k] = v
+}
+
+// logf is logger.Logf, but logger depends on envknob, so for circular
+// dependency reasons, make a type alias (so it's still assignable,
+// but has nice docs here).
+type logf = func(format string, args ...any)
+
+// LogCurrent logs the currently set environment knobs.
+func LogCurrent(logf logf) {
+	mu.Lock()
+	defer mu.Unlock()
+	for _, k := range list {
+		logf("envknob: %s=%q", k, set[k])
+	}
+}
+
 // String returns the named environment variable, using os.Getenv.
 //
-// In the future it will also track usage for reporting on debug pages.
+// If the variable is non-empty, it's also tracked & logged as being
+// an in-use knob.
 func String(envVar string) string {
-	return os.Getenv(envVar)
+	v := os.Getenv(envVar)
+	noteEnv(envVar, v)
+	return v
 }
 
 // Bool returns the boolean value of the named environment variable.
@@ -51,9 +87,10 @@ func boolOr(envVar string, implicitValue bool) bool {
 	}
 	b, err := strconv.ParseBool(val)
 	if err == nil {
+		noteEnv(envVar, strconv.FormatBool(b)) // canonicalize
 		return b
 	}
-	log.Fatalf("invalid environment variable %s value %q: %v", envVar, val, err)
+	log.Fatalf("invalid boolean environment variable %s value %q", envVar, val)
 	panic("unreachable")
 }
 
@@ -69,7 +106,7 @@ func LookupBool(envVar string) (v bool, ok bool) {
 	if err == nil {
 		return b, true
 	}
-	log.Fatalf("invalid environment variable %s value %q: %v", envVar, val, err)
+	log.Fatalf("invalid boolean environment variable %s value %q", envVar, val)
 	panic("unreachable")
 }
 
@@ -95,12 +132,20 @@ func LookupInt(envVar string) (v int, ok bool) {
 	}
 	v, err := strconv.Atoi(val)
 	if err == nil {
+		noteEnv(envVar, val)
 		return v, true
 	}
-	log.Fatalf("invalid environment variable %s value %q: %v", envVar, val, err)
+	log.Fatalf("invalid integer environment variable %s: %v", envVar, val)
 	panic("unreachable")
 }
 
 // UseWIPCode is whether TAILSCALE_USE_WIP_CODE is set to permit use
 // of Work-In-Progress code.
 func UseWIPCode() bool { return Bool("TAILSCALE_USE_WIP_CODE") }
+
+// CanSSHD is whether the Tailscale SSH server is allowed to run.
+//
+// If disabled, the SSH server won't start (won't intercept port 22)
+// if already enabled and any attempt to re-enable it will result in
+// an error.
+func CanSSHD() bool { return !Bool("TS_DISABLE_SSH_SERVER") }

go.mod

@@ -1,12 +1,13 @@
 module tailscale.com
 
-go 1.17
+go 1.18
 
 require (
 	filippo.io/mkcert v1.4.3
 	github.com/akutz/memconn v0.1.0
+	github.com/alessio/shellescape v1.4.1
 	github.com/alexbrainman/sspi v0.0.0-20210105120005-909beea2cc74
-	github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be // indirect
+	github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be
 	github.com/aws/aws-sdk-go-v2 v1.11.2
 	github.com/aws/aws-sdk-go-v2/config v1.11.0
 	github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.7.4
@@ -16,48 +17,48 @@ require (
 	github.com/creack/pty v1.1.17
 	github.com/dave/jennifer v1.4.1
 	github.com/frankban/quicktest v1.14.0
-	github.com/gliderlabs/ssh v0.3.3
 	github.com/go-ole/go-ole v1.2.6
 	github.com/godbus/dbus/v5 v5.0.6
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da
-	github.com/google/go-cmp v0.5.6
+	github.com/google/go-cmp v0.5.7
 	github.com/google/uuid v1.3.0
 	github.com/goreleaser/nfpm v1.10.3
 	github.com/iancoleman/strcase v0.2.0
-	github.com/insomniacslk/dhcp v0.0.0-20211026125128-ad197bcd36fd
-	github.com/jsimonetti/rtnetlink v0.0.0-20211203074127-fd9a11f42291
+	github.com/insomniacslk/dhcp v0.0.0-20211209223715-7d93572ebe8e
+	github.com/jsimonetti/rtnetlink v1.1.2-0.20220408201609-d380b505068b
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51
 	github.com/klauspost/compress v1.13.6
-	github.com/mdlayher/netlink v1.4.2
-	github.com/mdlayher/sdnotify v0.0.0-20210228150836-ea3ec207d697
+	github.com/mdlayher/genetlink v1.2.0
+	github.com/mdlayher/netlink v1.6.0
+	github.com/mdlayher/sdnotify v1.0.0
 	github.com/miekg/dns v1.1.43
 	github.com/mitchellh/go-ps v1.0.0
-	github.com/pborman/getopt v1.1.0
 	github.com/peterbourgon/ff/v3 v3.1.2
 	github.com/pkg/sftp v1.13.4
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
-	github.com/tailscale/certstore v0.0.0-20210528134328-066c94b793d3
+	github.com/tailscale/certstore v0.1.1-0.20220316223106-78d6e1c49d8d
 	github.com/tailscale/depaware v0.0.0-20210622194025-720c4b409502
 	github.com/tailscale/goexpect v0.0.0-20210902213824-6e8c725cea41
+	github.com/tailscale/golang-x-crypto v0.0.0-20220330002111-62119522bbcf
 	github.com/tailscale/goupnp v1.0.1-0.20210804011211-c64d0f06ea05
 	github.com/tailscale/hujson v0.0.0-20211105212140-3a0adc019d83
 	github.com/tailscale/netlink v1.1.1-0.20211101221916-cabfb018fe85
 	github.com/tcnksm/go-httpstat v0.2.0
 	github.com/toqueteos/webbrowser v1.2.0
-	github.com/ulikunitz/xz v0.5.10 // indirect
-	github.com/vishvananda/netlink v1.1.1-0.20211101163509-b10eb8fe5cf6
+	github.com/u-root/u-root v0.8.0
+	github.com/vishvananda/netlink v1.1.1-0.20211118161826-650dca95af54
 	go4.org/mem v0.0.0-20210711025021-927187094b94
-	golang.org/x/crypto v0.0.0-20211202192323-5770296d904e
-	golang.org/x/net v0.0.0-20211205041911-012df41ee64c
+	golang.org/x/crypto v0.0.0-20220321153916-2c7772ba3064
+	golang.org/x/net v0.0.0-20220407224826-aac1ed45d8e3
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
-	golang.org/x/sys v0.0.0-20211205182925-97ca703d548d
+	golang.org/x/sys v0.0.0-20220408201424-a24fb2fb8a0f
 	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211
 	golang.org/x/time v0.0.0-20211116232009-f0f3c7e86c11
-	golang.org/x/tools v0.1.8
-	golang.zx2c4.com/wireguard v0.0.0-20211116201604-de7c702ace45
+	golang.org/x/tools v0.1.11-0.20220413170336-afc6aad76eb1
+	golang.zx2c4.com/wireguard v0.0.0-20220317000134-95b48cdb3961
 	golang.zx2c4.com/wireguard/windows v0.4.10
-	gvisor.dev/gvisor v0.0.0-20220126021142-d8aa030b2591
-	honnef.co/go/tools v0.2.2
+	gvisor.dev/gvisor v0.0.0-20220407223209-21871174d445
+	honnef.co/go/tools v0.4.0-0.dev.0.20220404092545-59d7a2877f83
 	inet.af/netaddr v0.0.0-20211027220019-c74959edd3b6
 	inet.af/peercred v0.0.0-20210906144145-0893ea02156a
 	inet.af/wf v0.0.0-20211204062712-86aaea0a7310
@@ -68,7 +69,7 @@ require (
 	4d63.com/gochecknoglobals v0.1.0 // indirect
 	github.com/Antonboom/errname v0.1.5 // indirect
 	github.com/Antonboom/nilnil v0.1.0 // indirect
-	github.com/BurntSushi/toml v0.4.1 // indirect
+	github.com/BurntSushi/toml v1.1.0 // indirect
 	github.com/Djarvur/go-err113 v0.1.0 // indirect
 	github.com/Masterminds/goutils v1.1.1 // indirect
 	github.com/Masterminds/semver v1.5.0 // indirect
@@ -104,6 +105,7 @@ require (
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/charithe/durationcheck v0.0.9 // indirect
 	github.com/chavacava/garif v0.0.0-20210405164556-e8a0a408d6af // indirect
+	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf // indirect
 	github.com/daixiang0/gci v0.2.9 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/denis-tingajkin/go-header v0.4.2 // indirect
@@ -114,6 +116,7 @@ require (
 	github.com/fatih/structtag v1.2.0 // indirect
 	github.com/fsnotify/fsnotify v1.5.1 // indirect
 	github.com/fzipp/gocyclo v0.3.1 // indirect
+	github.com/gliderlabs/ssh v0.3.3 // indirect
 	github.com/go-critic/go-critic v0.6.1 // indirect
 	github.com/go-git/gcfg v1.5.0 // indirect
 	github.com/go-git/go-billy/v5 v5.3.1 // indirect
@@ -160,7 +163,7 @@ require (
 	github.com/jingyugao/rowserrcheck v1.1.1 // indirect
 	github.com/jirfag/go-printf-func-name v0.0.0-20200119135958-7558a9eaa5af // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
-	github.com/josharian/native v0.0.0-20200817173448-b6b71def0850 // indirect
+	github.com/josharian/native v1.0.0 // indirect
 	github.com/julz/importas v0.0.0-20210922140945-27e0a5d4dee2 // indirect
 	github.com/kevinburke/ssh_config v1.1.0 // indirect
 	github.com/kisielk/errcheck v1.6.0 // indirect
@@ -181,7 +184,7 @@ require (
 	github.com/mattn/go-runewidth v0.0.13 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/mbilski/exhaustivestruct v1.2.0 // indirect
-	github.com/mdlayher/socket v0.0.0-20211102153432-57e3fa563ecb // indirect
+	github.com/mdlayher/socket v0.2.3 // indirect
 	github.com/mgechev/dots v0.0.0-20210922191527-e955255bf517 // indirect
 	github.com/mgechev/revive v1.1.2 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
@@ -236,7 +239,8 @@ require (
 	github.com/timakin/bodyclose v0.0.0-20210704033933-f49887972144 // indirect
 	github.com/tomarrell/wrapcheck/v2 v2.4.0 // indirect
 	github.com/tommy-muehle/go-mnd/v2 v2.4.0 // indirect
-	github.com/u-root/uio v0.0.0-20210528114334-82958018845c // indirect
+	github.com/u-root/uio v0.0.0-20210528151154-e40b768296a7 // indirect
+	github.com/ulikunitz/xz v0.5.10 // indirect
 	github.com/ultraware/funlen v0.0.3 // indirect
 	github.com/ultraware/whitespace v0.0.4 // indirect
 	github.com/uudashr/gocognit v1.0.5 // indirect
@@ -245,7 +249,8 @@ require (
 	github.com/yeya24/promlinter v0.1.0 // indirect
 	go4.org/intern v0.0.0-20211027215823-ae77deb06f29 // indirect
 	go4.org/unsafe/assume-no-moving-gc v0.0.0-20211027215541-db492cf91b37 // indirect
-	golang.org/x/mod v0.5.1 // indirect
+	golang.org/x/exp/typeparams v0.0.0-20220328175248-053ad81199eb // indirect
+	golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 // indirect
 	golang.org/x/text v0.3.7 // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	golang.zx2c4.com/wintun v0.0.0-20211104114900-415007cec224 // indirect

go.sum

@@ -59,8 +59,9 @@ github.com/Antonboom/errname v0.1.5/go.mod h1:DugbBstvPFQbv/5uLcRRzfrNqKE9tVdVCq
 github.com/Antonboom/nilnil v0.1.0 h1:DLDavmg0a6G/F4Lt9t7Enrbgb3Oph6LnDE6YVsmTt74=
 github.com/Antonboom/nilnil v0.1.0/go.mod h1:PhHLvRPSghY5Y7mX4TW+BHZQYo1A8flE5H20D3IPZBo=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/BurntSushi/toml v0.4.1 h1:GaI7EiDXDRfa8VshkTj7Fym7ha+y8/XxIgD2okUIjLw=
 github.com/BurntSushi/toml v0.4.1/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=
+github.com/BurntSushi/toml v1.1.0 h1:ksErzDEI1khOiGPgpwuI7x2ebx/uXQNw7xJpn9Eq1+I=
+github.com/BurntSushi/toml v1.1.0/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/Djarvur/go-err113 v0.0.0-20200511133814-5174e21577d5/go.mod h1:4UJr5HIiMZrwgkSPdsjy2uOQExX/WEILpIrO9UPGuXs=
 github.com/Djarvur/go-err113 v0.0.0-20210108212216-aea10b59be24/go.mod h1:4UJr5HIiMZrwgkSPdsjy2uOQExX/WEILpIrO9UPGuXs=
@@ -103,6 +104,8 @@ github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuy
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
+github.com/alessio/shellescape v1.4.1 h1:V7yhSDDn8LP4lc4jS8pFkt0zCnzVJlG5JXy9BVKJUX0=
+github.com/alessio/shellescape v1.4.1/go.mod h1:PZAiSCk0LJaZkiCSkPv8qIobYglO3FPpyFjDCtHLS30=
 github.com/alexbrainman/sspi v0.0.0-20210105120005-909beea2cc74 h1:Kk6a4nehpJ3UuJRqlA3JxYxBZEqCeOmATOvrbT4p9RA=
 github.com/alexbrainman/sspi v0.0.0-20210105120005-909beea2cc74/go.mod h1:cEWa1LVoE5KvSD9ONXsZrj0z6KqySlCCNKHlLzbqAt4=
 github.com/alexkohler/prealloc v1.0.0 h1:Hbq0/3fJPQhNkN0dR95AVrr6R7tou91y0uHG5pOcUuw=
@@ -200,9 +203,8 @@ github.com/chavacava/garif v0.0.0-20210405164556-e8a0a408d6af/go.mod h1:Qjyv4H3/
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
-github.com/cilium/ebpf v0.5.0/go.mod h1:4tRaxcgiL706VnOzHOdBlY8IEAIdxINsQBcU4xJJXRs=
-github.com/cilium/ebpf v0.7.0 h1:1k/q3ATgxSXRdrmPfH8d7YK0GfqVsEKZAX9dQZvs56k=
-github.com/cilium/ebpf v0.7.0/go.mod h1:/oI2+1shJiTGAMgl6/RgJr36Eo1jzrRcAWbcXO2usCA=
+github.com/cilium/ebpf v0.8.1 h1:bLSSEbBLqGPXxls55pGr5qWZaTqcmfDJHhou7t254ao=
+github.com/cilium/ebpf v0.8.1/go.mod h1:f5zLIM0FSNuAkSyLAN7X+Hy6yznlF1mNiWUMfxMtrgk=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
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@@ -1120,8 +1108,11 @@ github.com/tommy-muehle/go-mnd/v2 v2.4.0 h1:1t0f8Uiaq+fqKteUR4N9Umr6E99R+lDnLnq7
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@@ -1148,8 +1139,8 @@ github.com/valyala/quicktemplate v1.7.0/go.mod h1:sqKJnoaOF88V07vkO+9FL8fb9uZg/V
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@@ -1236,8 +1227,8 @@ golang.org/x/crypto v0.0.0-20210711020723-a769d52b0f97/go.mod h1:GvvjBRRGRdwPK5y
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@@ -1250,6 +1241,8 @@ golang.org/x/exp v0.0.0-20200119233911-0405dc783f0a/go.mod h1:2RIsYlXP63K8oxa1u0
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@@ -1279,8 +1272,9 @@ golang.org/x/mod v0.4.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
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@@ -1329,8 +1323,6 @@ golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwY
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@@ -1344,11 +1336,10 @@ golang.org/x/net v0.0.0-20210805182204-aaa1db679c0d/go.mod h1:9nx3DQGgdP8bBQD5qx
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@@ -1445,18 +1436,13 @@ golang.org/x/sys v0.0.0-20201009025420-dfb3f7c4e634/go.mod h1:h1NjWce9XRLGQEsW7w
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@@ -1488,12 +1474,12 @@ golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBc
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-golang.org/x/sys v0.0.0-20211025201205-69cdffdb9359/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211102192858-4dd72447c267/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211105183446-c75c47738b0c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20211124211545-fe61309f8881/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20211205182925-97ca703d548d h1:FjkYO/PPp4Wi0EAUOVLxePm7qVW4r4ctbWpURyuOD0E=
-golang.org/x/sys v0.0.0-20211205182925-97ca703d548d/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220128215802-99c3d69c2c27/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220408201424-a24fb2fb8a0f h1:8w7RhxzTVgUzw/AH/9mUV5q0vMgy40SQRursCcfmkCw=
+golang.org/x/sys v0.0.0-20220408201424-a24fb2fb8a0f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 h1:JGgROgKl9N8DuW20oFS5gxc+lE67/N3FcwmBPMe7ArY=
@@ -1626,8 +1612,8 @@ golang.org/x/tools v0.1.5/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
 golang.org/x/tools v0.1.6/go.mod h1:LGqMHiF4EqQNHR1JncWGqT5BVaXmza+X+BDGol+dOxo=
 golang.org/x/tools v0.1.7/go.mod h1:LGqMHiF4EqQNHR1JncWGqT5BVaXmza+X+BDGol+dOxo=
 golang.org/x/tools v0.1.8-0.20211102182255-bb4add04ddef/go.mod h1:nABZi5QlRsZVlzPpHl034qft6wpY4eDcsTt5AaioBiU=
-golang.org/x/tools v0.1.8 h1:P1HhGGuLW4aAclzjtmJdf0mJOjVUZUzOTqkAkWL+l6w=
-golang.org/x/tools v0.1.8/go.mod h1:nABZi5QlRsZVlzPpHl034qft6wpY4eDcsTt5AaioBiU=
+golang.org/x/tools v0.1.11-0.20220413170336-afc6aad76eb1 h1:Z3vE1sGlC7qiyFJkkDcZms8Y3+yV8+W7HmDSmuf71tM=
+golang.org/x/tools v0.1.11-0.20220413170336-afc6aad76eb1/go.mod h1:Uh6Zz+xoGYZom868N8YTex3t7RhtHDBrE8Gzo9bV56E=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
@@ -1636,8 +1622,8 @@ golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8T
 golang.zx2c4.com/wintun v0.0.0-20211104114900-415007cec224 h1:Ug9qvr1myri/zFN6xL17LSCBGFDnphBBhzmILHsM5TY=
 golang.zx2c4.com/wintun v0.0.0-20211104114900-415007cec224/go.mod h1:deeaetjYA+DHMHg+sMSMI58GrEteJUUzzw7en6TJQcI=
 golang.zx2c4.com/wireguard v0.0.0-20210905140043-2ef39d47540c/go.mod h1:laHzsbfMhGSobUmruXWAyMKKHSqvIcrqZJMyHD+/3O8=
-golang.zx2c4.com/wireguard v0.0.0-20211116201604-de7c702ace45 h1:mEVhdMPTuebD9IUXOUB5Q2sjZpcmzkahHWd6DrGpLHA=
-golang.zx2c4.com/wireguard v0.0.0-20211116201604-de7c702ace45/go.mod h1:evxZIqfCetExY5piKXGAxJYwvXWkps9zTCkWpkoGFxw=
+golang.zx2c4.com/wireguard v0.0.0-20220317000134-95b48cdb3961 h1:oIXcKhP1Ge6cRqdpQuldl0hf4mjIsNaXojabghlHuTs=
+golang.zx2c4.com/wireguard v0.0.0-20220317000134-95b48cdb3961/go.mod h1:bVQfyl2sCM/QIIGHpWbFGfHPuDvqnCNkT6MQLTCjO/U=
 golang.zx2c4.com/wireguard/windows v0.4.10 h1:HmjzJnb+G4NCdX+sfjsQlsxGPuYaThxRbZUZFLyR0/s=
 golang.zx2c4.com/wireguard/windows v0.4.10/go.mod h1:v7w/8FC48tTBm1IzScDVPEEb0/GjLta+T0ybpP9UWRg=
 google.golang.org/api v0.4.0/go.mod h1:8k5glujaEP+g9n7WNsDg8QP6cUVNI86fCNMcbazEtwE=
@@ -1817,8 +1803,8 @@ gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C
 gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gvisor.dev/gvisor v0.0.0-20220126021142-d8aa030b2591 h1:acuXPUADpJMtawdLCUje9xKlQN/8utegCB/Hr/ZgEuY=
-gvisor.dev/gvisor v0.0.0-20220126021142-d8aa030b2591/go.mod h1:vmN0Pug/s8TJmpnt30DvrEfZ5vDl52psGLU04tFuK2U=
+gvisor.dev/gvisor v0.0.0-20220407223209-21871174d445 h1:pLNQCtMzh4O6rdhoUeWHuutt4yMft+B9Cgw/bezWchE=
+gvisor.dev/gvisor v0.0.0-20220407223209-21871174d445/go.mod h1:tWwEcFvJavs154OdjFCw78axNrsDlz4Zh8jvPqwcpGI=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
@@ -1828,8 +1814,8 @@ honnef.co/go/tools v0.0.1-2020.1.3/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9
 honnef.co/go/tools v0.0.1-2020.1.4/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=
 honnef.co/go/tools v0.0.1-2020.1.6/go.mod h1:pyyisuGw24ruLjrr1ddx39WE0y9OooInRzEYLhQB2YY=
 honnef.co/go/tools v0.2.1/go.mod h1:lPVVZ2BS5TfnjLyizF7o7hv7j9/L+8cZY2hLyjP9cGY=
-honnef.co/go/tools v0.2.2 h1:MNh1AVMyVX23VUHE2O27jm6lNj3vjO5DexS4A1xvnzk=
-honnef.co/go/tools v0.2.2/go.mod h1:lPVVZ2BS5TfnjLyizF7o7hv7j9/L+8cZY2hLyjP9cGY=
+honnef.co/go/tools v0.4.0-0.dev.0.20220404092545-59d7a2877f83 h1:lZ9GIYaU+o5+X6ST702I/Ntyq9Y2oIMZ42rBQpem64A=
+honnef.co/go/tools v0.4.0-0.dev.0.20220404092545-59d7a2877f83/go.mod h1:vlRD9XErLMGT+mDuofSr0mMMquscM/1nQqtRSsh6m70=
 howett.net/plist v0.0.0-20181124034731-591f970eefbb/go.mod h1:vMygbs4qMhSZSc4lCUl2OEE+rDiIIJAIdR4m7MiMcm0=
 howett.net/plist v1.0.0 h1:7CrbWYbPPO/PyNy38b2EB/+gYbjCe2DXBxgtOOZbSQM=
 howett.net/plist v1.0.0/go.mod h1:lqaXoTrLY4hg8tnEzNru53gicrbv7rrk+2xJA/7hw9g=

go.toolchain.branch

@@ -1 +1 @@
-tailscale.go1.17
+tailscale.go1.18

go.toolchain.rev

@@ -1 +1 @@
-25fe91a25c9630a50138a135105af19ae7c7c3e7
+5ce3ec4d89c72f2a2b6f6f5089c950d7a6a33530

health/health.go

@@ -64,6 +64,9 @@ const (
 	// SysDNSOS is the name of the net/dns OSConfigurator subsystem.
 	SysDNSOS = Subsystem("dns-os")
 
+	// SysDNSManager is the name of the net/dns manager subsystem.
+	SysDNSManager = Subsystem("dns-manager")
+
 	// SysNetworkCategory is the name of the subsystem that sets
 	// the Windows network adapter's "category" (public, private, domain).
 	// If it's unhealthy, the Windows firewall rules won't match.
@@ -110,6 +113,10 @@ func DNSHealth() error { return get(SysDNS) }
 // SetDNSOSHealth sets the state of the net/dns.OSConfigurator
 func SetDNSOSHealth(err error) { set(SysDNSOS, err) }
 
+// SetDNSManagerHealth sets the state of the Linux net/dns manager's
+// discovery of the /etc/resolv.conf situation.
+func SetDNSManagerHealth(err error) { set(SysDNSManager, err) }
+
 // DNSOSHealth returns the net/dns.OSConfigurator error state.
 func DNSOSHealth() error { return get(SysDNSOS) }
 

hostinfo/hostinfo.go

@@ -10,7 +10,6 @@ import (
 	"bufio"
 	"io"
 	"os"
-	"path/filepath"
 	"runtime"
 	"strings"
 	"sync/atomic"
@@ -32,13 +31,17 @@ func New() *tailcfg.Hostinfo {
 		Hostname:    hostname,
 		OS:          version.OS(),
 		OSVersion:   GetOSVersion(),
-		Package:     packageType(),
+		Package:     packageTypeCached(),
 		GoArch:      runtime.GOARCH,
 		DeviceModel: deviceModel(),
 	}
 }
 
-var osVersion func() string // non-nil on some platforms
+// non-nil on some platforms
+var (
+	osVersion   func() string
+	packageType func() string
+)
 
 // GetOSVersion returns the OSVersion of current host if available.
 func GetOSVersion() string {
@@ -51,28 +54,18 @@ func GetOSVersion() string {
 	return ""
 }
 
-func packageType() string {
+func packageTypeCached() string {
 	if v, _ := packagingType.Load().(string); v != "" {
 		return v
 	}
-	switch runtime.GOOS {
-	case "windows":
-		if _, err := os.Stat(`C:\ProgramData\chocolatey\lib\tailscale`); err == nil {
-			return "choco"
-		}
-	case "darwin":
-		// Using tailscaled or IPNExtension?
-		exe, _ := os.Executable()
-		return filepath.Base(exe)
-	case "linux":
-		// Report whether this is in a snap.
-		// See https://snapcraft.io/docs/environment-variables
-		// We just look at two somewhat arbitrarily.
-		if os.Getenv("SNAP_NAME") != "" && os.Getenv("SNAP") != "" {
-			return "snap"
-		}
+	if packageType == nil {
+		return ""
 	}
-	return ""
+	v := packageType()
+	if v != "" {
+		SetPackage(v)
+	}
+	return v
 }
 
 // EnvType represents a known environment type.
@@ -114,8 +107,9 @@ func SetDeviceModel(model string) { deviceModelAtomic.Store(model) }
 func SetOSVersion(v string) { osVersionAtomic.Store(v) }
 
 // SetPackage sets the packaging type for the app.
-// This is currently (2021-10-05) only used by Android,
-// set to "nogoogle" for the F-Droid build.
+//
+// As of 2022-03-25, this is used by Android ("nogoogle" for the
+// F-Droid build) and tsnet (set to "tsnet").
 func SetPackage(v string) { packagingType.Store(v) }
 
 func deviceModel() string {

hostinfo/hostinfo_darwin.go

@@ -0,0 +1,23 @@
+// 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 darwin
+// +build darwin
+
+package hostinfo
+
+import (
+	"os"
+	"path/filepath"
+)
+
+func init() {
+	packageType = packageTypeDarwin
+}
+
+func packageTypeDarwin() string {
+	// Using tailscaled or IPNExtension?
+	exe, _ := os.Executable()
+	return filepath.Base(exe)
+}

hostinfo/hostinfo_linux.go

@@ -21,6 +21,7 @@ import (
 
 func init() {
 	osVersion = osVersionLinux
+	packageType = packageTypeLinux
 
 	if v := linuxDeviceModel(); v != "" {
 		SetDeviceModel(v)
@@ -112,6 +113,18 @@ func osVersionLinux() string {
 		return fmt.Sprintf("Synology %s%s", m["productversion"], attr)
 	case distro.OpenWrt:
 		return fmt.Sprintf("OpenWrt %s%s", m["DISTRIB_RELEASE"], attr)
+	case distro.Gokrazy:
+		return fmt.Sprintf("Gokrazy%s", attr)
 	}
 	return fmt.Sprintf("Other%s", attr)
 }
+
+func packageTypeLinux() string {
+	// Report whether this is in a snap.
+	// See https://snapcraft.io/docs/environment-variables
+	// We just look at two somewhat arbitrarily.
+	if os.Getenv("SNAP_NAME") != "" && os.Getenv("SNAP") != "" {
+		return "snap"
+	}
+	return ""
+}

hostinfo/hostinfo_windows.go

@@ -6,14 +6,18 @@ package hostinfo
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
 	"sync/atomic"
 
 	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/registry"
+	"tailscale.com/util/winutil"
 )
 
 func init() {
 	osVersion = osVersionWindows
+	packageType = packageTypeWindows
 }
 
 var winVerCache atomic.Value // of string
@@ -56,3 +60,25 @@ func getUBR() (uint32, error) {
 
 	return uint32(val), nil
 }
+
+func packageTypeWindows() string {
+	if _, err := os.Stat(`C:\ProgramData\chocolatey\lib\tailscale`); err == nil {
+		return "choco"
+	}
+	if msiSentinel := winutil.GetRegInteger("MSI", 0); msiSentinel == 1 {
+		return "msi"
+	}
+	exe, err := os.Executable()
+	if err != nil {
+		return ""
+	}
+	dir := filepath.Dir(exe)
+	nsisUninstaller := filepath.Join(dir, "Uninstall-Tailscale.exe")
+	_, err = os.Stat(nsisUninstaller)
+	if err == nil {
+		return "nsis"
+	}
+	// Atypical. Not worth trying to detect. Likely open
+	// source tailscaled or a developer running by hand.
+	return ""
+}

ipn/ipnlocal/local.go

@@ -5,7 +5,6 @@
 package ipnlocal
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -13,7 +12,6 @@ import (
 	"net"
 	"net/http"
 	"os"
-	"os/exec"
 	"os/user"
 	"path/filepath"
 	"runtime"
@@ -35,6 +33,7 @@ import (
 	"tailscale.com/ipn/policy"
 	"tailscale.com/net/dns"
 	"tailscale.com/net/interfaces"
+	"tailscale.com/net/netutil"
 	"tailscale.com/net/tsaddr"
 	"tailscale.com/net/tsdial"
 	"tailscale.com/paths"
@@ -48,6 +47,7 @@ import (
 	"tailscale.com/types/netmap"
 	"tailscale.com/types/persist"
 	"tailscale.com/types/preftype"
+	"tailscale.com/types/views"
 	"tailscale.com/util/deephash"
 	"tailscale.com/util/dnsname"
 	"tailscale.com/util/multierr"
@@ -64,6 +64,7 @@ import (
 )
 
 var controlDebugFlags = getControlDebugFlags()
+var canSSH = envknob.CanSSHD()
 
 func getControlDebugFlags() []string {
 	if e := envknob.String("TS_DEBUG_CONTROL_FLAGS"); e != "" {
@@ -105,7 +106,8 @@ type LocalBackend struct {
 
 	filterHash deephash.Sum
 
-	filterAtomic atomic.Value // of *filter.Filter
+	filterAtomic            atomic.Value // of *filter.Filter
+	containsViaIPFuncAtomic atomic.Value // of func(netaddr.IP) bool
 
 	// The mutex protects the following elements.
 	mu             sync.Mutex
@@ -136,7 +138,9 @@ type LocalBackend struct {
 	prevIfState      *interfaces.State
 	peerAPIServer    *peerAPIServer // or nil
 	peerAPIListeners []*peerAPIListener
+	loginFlags       controlclient.LoginFlags
 	incomingFiles    map[*incomingFile]bool
+	lastStatusTime   time.Time // status.AsOf value of the last processed status update
 	// directFileRoot, if non-empty, means to write received files
 	// directly to this directory, without staging them in an
 	// intermediate buffered directory for "pick-up" later. If
@@ -166,10 +170,14 @@ type clientGen func(controlclient.Options) (controlclient.Client, error)
 // but is not actually running.
 //
 // If dialer is nil, a new one is made.
-func NewLocalBackend(logf logger.Logf, logid string, store ipn.StateStore, dialer *tsdial.Dialer, e wgengine.Engine) (*LocalBackend, error) {
+func NewLocalBackend(logf logger.Logf, logid string, store ipn.StateStore, dialer *tsdial.Dialer, e wgengine.Engine, loginFlags controlclient.LoginFlags) (*LocalBackend, error) {
 	if e == nil {
 		panic("ipn.NewLocalBackend: engine must not be nil")
 	}
+
+	hi := hostinfo.New()
+	logf.JSON(1, "Hostinfo", hi)
+	envknob.LogCurrent(logf)
 	if dialer == nil {
 		dialer = new(tsdial.Dialer)
 	}
@@ -195,6 +203,7 @@ func NewLocalBackend(logf logger.Logf, logid string, store ipn.StateStore, diale
 		state:          ipn.NoState,
 		portpoll:       portpoll,
 		gotPortPollRes: make(chan struct{}),
+		loginFlags:     loginFlags,
 	}
 
 	// Default filter blocks everything and logs nothing, until Start() is called.
@@ -379,9 +388,14 @@ func (b *LocalBackend) updateStatus(sb *ipnstate.StatusBuilder, extraLocked func
 			}
 		}
 		if b.netMap != nil {
-			s.MagicDNSSuffix = b.netMap.MagicDNSSuffix()
 			s.CertDomains = append([]string(nil), b.netMap.DNS.CertDomains...)
-			s.TailnetName = b.netMap.Domain
+			s.MagicDNSSuffix = b.netMap.MagicDNSSuffix()
+			if s.CurrentTailnet == nil {
+				s.CurrentTailnet = &ipnstate.TailnetStatus{}
+			}
+			s.CurrentTailnet.MagicDNSSuffix = b.netMap.MagicDNSSuffix()
+			s.CurrentTailnet.MagicDNSEnabled = b.netMap.DNS.Proxied
+			s.CurrentTailnet.Name = b.netMap.Domain
 		}
 	})
 	sb.MutateSelfStatus(func(ss *ipnstate.PeerStatus) {
@@ -432,21 +446,34 @@ func (b *LocalBackend) populatePeerStatusLocked(sb *ipnstate.StatusBuilder) {
 		exitNodeOption := tsaddr.PrefixesContainsFunc(p.AllowedIPs, func(r netaddr.IPPrefix) bool {
 			return r.Bits() == 0
 		})
+		var tags *views.Slice[string]
+		var primaryRoutes *views.IPPrefixSlice
+		if p.Tags != nil {
+			v := views.SliceOf(p.Tags)
+			tags = &v
+		}
+		if p.PrimaryRoutes != nil {
+			v := views.IPPrefixSliceOf(p.PrimaryRoutes)
+			primaryRoutes = &v
+		}
 		sb.AddPeer(p.Key, &ipnstate.PeerStatus{
 			InNetworkMap:   true,
 			ID:             p.StableID,
 			UserID:         p.User,
 			TailscaleIPs:   tailscaleIPs,
-			HostName:       p.Hostinfo.Hostname,
+			Tags:           tags,
+			PrimaryRoutes:  primaryRoutes,
+			HostName:       p.Hostinfo.Hostname(),
 			DNSName:        p.Name,
-			OS:             p.Hostinfo.OS,
+			OS:             p.Hostinfo.OS(),
 			KeepAlive:      p.KeepAlive,
 			Created:        p.Created,
 			LastSeen:       lastSeen,
 			Online:         p.Online != nil && *p.Online,
-			ShareeNode:     p.Hostinfo.ShareeNode,
+			ShareeNode:     p.Hostinfo.ShareeNode(),
 			ExitNode:       p.StableID != "" && p.StableID == b.prefs.ExitNodeID,
 			ExitNodeOption: exitNodeOption,
+			SSH_HostKeys:   p.Hostinfo.SSH_HostKeys().AsSlice(),
 		})
 	}
 }
@@ -607,7 +634,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 			if strings.TrimSpace(diff) == "" {
 				b.logf("[v1] netmap diff: (none)")
 			} else {
-				b.logf("netmap diff:\n%v", diff)
+				b.logf("[v1] netmap diff:\n%v", diff)
 			}
 		}
 
@@ -680,6 +707,13 @@ func (b *LocalBackend) setWgengineStatus(s *wgengine.Status, err error) {
 	}
 
 	b.mu.Lock()
+	if s.AsOf.Before(b.lastStatusTime) {
+		// Don't process a status update that is older than the one we have
+		// already processed. (corp#2579)
+		b.mu.Unlock()
+		return
+	}
+	b.lastStatusTime = s.AsOf
 	es := b.parseWgStatusLocked(s)
 	cc := b.cc
 	b.engineStatus = es
@@ -885,7 +919,7 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 	if b.inServerMode || runtime.GOOS == "windows" {
 		b.logf("Start: serverMode=%v", b.inServerMode)
 	}
-	applyPrefsToHostinfo(hostinfo, b.prefs)
+	b.applyPrefsToHostinfo(hostinfo, b.prefs)
 
 	b.setNetMapLocked(nil)
 	persistv := b.prefs.Persist
@@ -906,7 +940,7 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 			timer := time.NewTimer(time.Second)
 			select {
 			case <-b.gotPortPollRes:
-				b.logf("got initial portlist info in %v", time.Since(t0).Round(time.Millisecond))
+				b.logf("[v1] got initial portlist info in %v", time.Since(t0).Round(time.Millisecond))
 				timer.Stop()
 			case <-timer.C:
 				b.logf("timeout waiting for initial portlist")
@@ -949,6 +983,7 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 		DebugFlags:           debugFlags,
 		LinkMonitor:          b.e.GetLinkMonitor(),
 		Pinger:               b.e,
+		PopBrowserURL:        b.tellClientToBrowseToURL,
 
 		// Don't warn about broken Linux IP forwarding when
 		// netstack is being used.
@@ -1054,17 +1089,17 @@ func (b *LocalBackend) updateFilter(netMap *netmap.NetworkMap, prefs *ipn.Prefs)
 	}
 
 	if !haveNetmap {
-		b.logf("netmap packet filter: (not ready yet)")
+		b.logf("[v1] netmap packet filter: (not ready yet)")
 		b.setFilter(filter.NewAllowNone(b.logf, logNets))
 		return
 	}
 
 	oldFilter := b.e.GetFilter()
 	if shieldsUp {
-		b.logf("netmap packet filter: (shields up)")
+		b.logf("[v1] netmap packet filter: (shields up)")
 		b.setFilter(filter.NewShieldsUpFilter(localNets, logNets, oldFilter, b.logf))
 	} else {
-		b.logf("netmap packet filter: %v filters", len(packetFilter))
+		b.logf("[v1] netmap packet filter: %v filters", len(packetFilter))
 		b.setFilter(filter.New(packetFilter, localNets, logNets, oldFilter, b.logf))
 	}
 }
@@ -1346,12 +1381,18 @@ func (b *LocalBackend) popBrowserAuthNow() {
 
 	b.blockEngineUpdates(true)
 	b.stopEngineAndWait()
-	b.send(ipn.Notify{BrowseToURL: &url})
+	b.tellClientToBrowseToURL(url)
 	if b.State() == ipn.Running {
 		b.enterState(ipn.Starting)
 	}
 }
 
+func (b *LocalBackend) tellClientToBrowseToURL(url string) {
+	if url != "" {
+		b.send(ipn.Notify{BrowseToURL: &url})
+	}
+}
+
 // For testing lazy machine key generation.
 var panicOnMachineKeyGeneration = envknob.Bool("TS_DEBUG_PANIC_MACHINE_KEY")
 
@@ -1503,48 +1544,53 @@ func (b *LocalBackend) loadStateLocked(key ipn.StateKey, prefs *ipn.Prefs) (err
 		}
 	}
 
-	b.logf("using backend prefs")
 	bs, err := b.store.ReadState(key)
 	switch {
 	case errors.Is(err, ipn.ErrStateNotExist):
 		b.prefs = ipn.NewPrefs()
 		b.prefs.WantRunning = false
-		b.logf("created empty state for %q: %s", key, b.prefs.Pretty())
+		b.logf("using backend prefs; created empty state for %q: %s", key, b.prefs.Pretty())
 		return nil
 	case err != nil:
-		return fmt.Errorf("store.ReadState(%q): %v", key, err)
+		return fmt.Errorf("backend prefs: store.ReadState(%q): %v", key, err)
 	}
 	b.prefs, err = ipn.PrefsFromBytes(bs, false)
 	if err != nil {
+		b.logf("using backend prefs for %q", key)
 		return fmt.Errorf("PrefsFromBytes: %v", err)
 	}
 
-	// On mobile platforms, ignore any old stored preferences for
-	// https://login.tailscale.com as the control server that
-	// would override the new default of controlplane.tailscale.com.
+	// Ignore any old stored preferences for https://login.tailscale.com
+	// as the control server that would override the new default of
+	// controlplane.tailscale.com.
 	// This makes sure that mobile clients go through the new
 	// frontends where we're (2021-10-02) doing battery
 	// optimization work ahead of turning down the old backends.
-	// TODO(bradfitz): make this the default for all platforms
-	// later. But mobile is a relatively small chunk (compared to
-	// Linux, Windows, macOS) and moving mobile early for battery
-	// gains is nice.
-	switch runtime.GOOS {
-	case "android", "ios":
-		if b.prefs != nil && b.prefs.ControlURL != "" &&
-			b.prefs.ControlURL != ipn.DefaultControlURL &&
-			ipn.IsLoginServerSynonym(b.prefs.ControlURL) {
-			b.prefs.ControlURL = ""
-		}
+	if b.prefs != nil && b.prefs.ControlURL != "" &&
+		b.prefs.ControlURL != ipn.DefaultControlURL &&
+		ipn.IsLoginServerSynonym(b.prefs.ControlURL) {
+		b.prefs.ControlURL = ""
 	}
 
-	b.logf("backend prefs for %q: %s", key, b.prefs.Pretty())
+	b.logf("using backend prefs for %q: %s", key, b.prefs.Pretty())
 
-	b.sshAtomicBool.Set(b.prefs != nil && b.prefs.RunSSH)
+	b.setAtomicValuesFromPrefs(b.prefs)
 
 	return nil
 }
 
+// setAtomicValuesFromPrefs populates sshAtomicBool and containsViaIPFuncAtomic
+// from the prefs p, which may be nil.
+func (b *LocalBackend) setAtomicValuesFromPrefs(p *ipn.Prefs) {
+	b.sshAtomicBool.Set(p != nil && p.RunSSH && canSSH)
+
+	if p == nil {
+		b.containsViaIPFuncAtomic.Store(tsaddr.NewContainsIPFunc(nil))
+	} else {
+		b.containsViaIPFuncAtomic.Store(tsaddr.NewContainsIPFunc(tsaddr.FilterPrefixesCopy(p.AdvertiseRoutes, tsaddr.IsViaPrefix)))
+	}
+}
+
 // State returns the backend state machine's current state.
 func (b *LocalBackend) State() ipn.State {
 	b.mu.Lock()
@@ -1560,13 +1606,14 @@ func (b *LocalBackend) InServerMode() bool {
 }
 
 // Login implements Backend.
+// As of 2022-02-17, this is only exists for tests.
 func (b *LocalBackend) Login(token *tailcfg.Oauth2Token) {
 	b.mu.Lock()
 	b.assertClientLocked()
 	cc := b.cc
 	b.mu.Unlock()
 
-	cc.Login(token, controlclient.LoginInteractive)
+	cc.Login(token, b.loginFlags|controlclient.LoginInteractive)
 }
 
 // StartLoginInteractive implements Backend. It requests a new
@@ -1585,15 +1632,7 @@ func (b *LocalBackend) StartLoginInteractive() {
 	if url != "" {
 		b.popBrowserAuthNow()
 	} else {
-		flags := controlclient.LoginInteractive
-		if runtime.GOOS == "js" {
-			// The js/wasm client has no state storage so for now
-			// treat all interactive logins as ephemeral.
-			// TODO(bradfitz): if we start using browser LocalStorage
-			// or something, then rethink this.
-			flags |= controlclient.LoginEphemeral
-		}
-		cc.Login(nil, flags)
+		cc.Login(nil, b.loginFlags|controlclient.LoginInteractive)
 	}
 }
 
@@ -1686,6 +1725,11 @@ func (b *LocalBackend) EditPrefs(mp *ipn.MaskedPrefs) (*ipn.Prefs, error) {
 	p0 := b.prefs.Clone()
 	p1 := b.prefs.Clone()
 	p1.ApplyEdits(mp)
+	if p1.RunSSH && !canSSH {
+		b.mu.Unlock()
+		b.logf("EditPrefs requests SSH, but disabled by envknob; returning error")
+		return nil, errors.New("Tailscale SSH server administratively disabled.")
+	}
 	if p1.Equals(p0) {
 		b.mu.Unlock()
 		return p1, nil
@@ -1715,7 +1759,7 @@ func (b *LocalBackend) setPrefsLockedOnEntry(caller string, newp *ipn.Prefs) {
 	netMap := b.netMap
 	stateKey := b.stateKey
 
-	b.sshAtomicBool.Set(newp.RunSSH)
+	b.setAtomicValuesFromPrefs(newp)
 
 	oldp := b.prefs
 	newp.Persist = oldp.Persist // caller isn't allowed to override this
@@ -1730,7 +1774,7 @@ func (b *LocalBackend) setPrefsLockedOnEntry(caller string, newp *ipn.Prefs) {
 
 	oldHi := b.hostinfo
 	newHi := oldHi.Clone()
-	applyPrefsToHostinfo(newHi, newp)
+	b.applyPrefsToHostinfo(newHi, newp)
 	b.hostinfo = newHi
 	hostInfoChanged := !oldHi.Equal(newHi)
 	userID := b.userID
@@ -1913,18 +1957,19 @@ func (b *LocalBackend) authReconfig() {
 	nm := b.netMap
 	hasPAC := b.prevIfState.HasPAC()
 	disableSubnetsIfPAC := nm != nil && nm.Debug != nil && nm.Debug.DisableSubnetsIfPAC.EqualBool(true)
+	oneCGNATRoute := nm != nil && nm.Debug != nil && nm.Debug.OneCGNATRoute.EqualBool(true)
 	b.mu.Unlock()
 
 	if blocked {
-		b.logf("authReconfig: blocked, skipping.")
+		b.logf("[v1] authReconfig: blocked, skipping.")
 		return
 	}
 	if nm == nil {
-		b.logf("authReconfig: netmap not yet valid. Skipping.")
+		b.logf("[v1] authReconfig: netmap not yet valid. Skipping.")
 		return
 	}
 	if !prefs.WantRunning {
-		b.logf("authReconfig: skipping because !WantRunning.")
+		b.logf("[v1] authReconfig: skipping because !WantRunning.")
 		return
 	}
 
@@ -1957,7 +2002,7 @@ func (b *LocalBackend) authReconfig() {
 		return
 	}
 
-	rcfg := b.routerConfig(cfg, prefs)
+	rcfg := b.routerConfig(cfg, prefs, oneCGNATRoute)
 	dcfg := dnsConfigForNetmap(nm, prefs, b.logf, version.OS())
 
 	err = b.e.Reconfig(cfg, rcfg, dcfg, nm.Debug)
@@ -2353,17 +2398,32 @@ func peerRoutes(peers []wgcfg.Peer, cgnatThreshold int) (routes []netaddr.IPPref
 	} else {
 		routes = append(routes, cgNATIPs...)
 	}
+
+	sort.Slice(routes, func(i, j int) bool {
+		return ipPrefixLess(routes[i], routes[j])
+	})
 	return routes
 }
 
+func ipPrefixLess(ri, rj netaddr.IPPrefix) bool {
+	if ri.IP() == rj.IP() {
+		return ri.Bits() < rj.Bits()
+	}
+	return ri.IP().Less(rj.IP())
+}
+
 // routerConfig produces a router.Config from a wireguard config and IPN prefs.
-func (b *LocalBackend) routerConfig(cfg *wgcfg.Config, prefs *ipn.Prefs) *router.Config {
+func (b *LocalBackend) routerConfig(cfg *wgcfg.Config, prefs *ipn.Prefs, oneCGNATRoute bool) *router.Config {
+	singleRouteThreshold := 10_000
+	if oneCGNATRoute {
+		singleRouteThreshold = 1
+	}
 	rs := &router.Config{
 		LocalAddrs:       unmapIPPrefixes(cfg.Addresses),
 		SubnetRoutes:     unmapIPPrefixes(prefs.AdvertiseRoutes),
 		SNATSubnetRoutes: !prefs.NoSNAT,
 		NetfilterMode:    prefs.NetfilterMode,
-		Routes:           peerRoutes(cfg.Peers, 10_000),
+		Routes:           peerRoutes(cfg.Peers, singleRouteThreshold),
 	}
 
 	if distro.Get() == distro.Synology {
@@ -2435,13 +2495,23 @@ func unmapIPPrefixes(ippsList ...[]netaddr.IPPrefix) (ret []netaddr.IPPrefix) {
 	return ret
 }
 
-func applyPrefsToHostinfo(hi *tailcfg.Hostinfo, prefs *ipn.Prefs) {
+// Warning: b.mu might be held. Currently (2022-02-17) both callers hold it.
+func (b *LocalBackend) applyPrefsToHostinfo(hi *tailcfg.Hostinfo, prefs *ipn.Prefs) {
 	if h := prefs.Hostname; h != "" {
 		hi.Hostname = h
 	}
 	hi.RoutableIPs = append(prefs.AdvertiseRoutes[:0:0], prefs.AdvertiseRoutes...)
 	hi.RequestTags = append(prefs.AdvertiseTags[:0:0], prefs.AdvertiseTags...)
 	hi.ShieldsUp = prefs.ShieldsUp
+
+	var sshHostKeys []string
+	if prefs.RunSSH && canSSH {
+		// TODO(bradfitz): this is called with b.mu held. Not ideal.
+		// If the filesystem gets wedged or something we could block for
+		// a long time. But probably fine.
+		sshHostKeys = b.getSSHHostKeyPublicStrings()
+	}
+	hi.SSH_HostKeys = sshHostKeys
 }
 
 // enterState transitions the backend into newState, updating internal
@@ -2649,10 +2719,20 @@ func (b *LocalBackend) ResetForClientDisconnect() {
 	b.authURL = ""
 	b.authURLSticky = ""
 	b.activeLogin = ""
-	b.sshAtomicBool.Set(false)
+	b.setAtomicValuesFromPrefs(nil)
 }
 
-func (b *LocalBackend) ShouldRunSSH() bool { return b.sshAtomicBool.Get() }
+func (b *LocalBackend) ShouldRunSSH() bool { return b.sshAtomicBool.Get() && canSSH }
+
+// ShouldHandleViaIP reports whether whether ip is an IPv6 address in the
+// Tailscale ULA's v6 "via" range embedding an IPv4 address to be forwarded to
+// by Tailscale.
+func (b *LocalBackend) ShouldHandleViaIP(ip netaddr.IP) bool {
+	if f, ok := b.containsViaIPFuncAtomic.Load().(func(netaddr.IP) bool); ok {
+		return f(ip)
+	}
+	return false
+}
 
 // Logout tells the controlclient that we want to log out, and
 // transitions the local engine to the logged-out state without
@@ -2903,7 +2983,7 @@ func (b *LocalBackend) FileTargets() ([]*apitype.FileTarget, error) {
 // friendly options to get HTTPS certs.
 func (b *LocalBackend) SetDNS(ctx context.Context, name, value string) error {
 	req := &tailcfg.SetDNSRequest{
-		Version: 1,
+		Version: 1, // TODO(bradfitz,maisem): use tailcfg.CurrentCapabilityVersion when using the Noise transport
 		Type:    "TXT",
 		Name:    name,
 		Value:   value,
@@ -2947,9 +3027,10 @@ func (b *LocalBackend) registerIncomingFile(inf *incomingFile, active bool) {
 // It returns the empty string if the peer doesn't support the peerapi
 // or there's no matching address family based on the netmap's own addresses.
 func peerAPIBase(nm *netmap.NetworkMap, peer *tailcfg.Node) string {
-	if nm == nil || peer == nil {
+	if nm == nil || peer == nil || !peer.Hostinfo.Valid() {
 		return ""
 	}
+
 	var have4, have6 bool
 	for _, a := range nm.Addresses {
 		if !a.IsSingleIP() {
@@ -2963,7 +3044,9 @@ func peerAPIBase(nm *netmap.NetworkMap, peer *tailcfg.Node) string {
 		}
 	}
 	var p4, p6 uint16
-	for _, s := range peer.Hostinfo.Services {
+	svcs := peer.Hostinfo.Services()
+	for i, n := 0, svcs.Len(); i < n; i++ {
+		s := svcs.At(i)
 		switch s.Proto {
 		case tailcfg.PeerAPI4:
 			p4 = s.Port
@@ -2993,105 +3076,17 @@ func nodeIP(n *tailcfg.Node, pred func(netaddr.IP) bool) netaddr.IP {
 	return netaddr.IP{}
 }
 
-func isBSD(s string) bool {
-	return s == "dragonfly" || s == "freebsd" || s == "netbsd" || s == "openbsd"
-}
-
 func (b *LocalBackend) CheckIPForwarding() error {
 	if wgengine.IsNetstackRouter(b.e) {
 		return nil
 	}
 
-	switch {
-	case isBSD(runtime.GOOS):
-		return fmt.Errorf("Subnet routing and exit nodes only work with additional manual configuration on %v, and is not currently officially supported.", runtime.GOOS)
-	case runtime.GOOS == "linux":
-		return checkIPForwardingLinux()
-	default:
-		// TODO: subnet routing and exit nodes probably don't work
-		// correctly on non-linux, non-netstack OSes either. Warn
-		// instead of being silent?
-		return nil
-	}
-}
-
-// checkIPForwardingLinux checks if IP forwarding is enabled correctly
-// for subnet routing and exit node functionality. Returns an error
-// describing configuration issues if the configuration is not
-// definitely good.
-func checkIPForwardingLinux() error {
-	const kbLink = "\nSee https://tailscale.com/kb/1104/enable-ip-forwarding/"
-
-	disabled, err := disabledSysctls("net.ipv4.ip_forward", "net.ipv6.conf.all.forwarding")
+	// TODO: let the caller pass in the ranges.
+	warn, err := netutil.CheckIPForwarding(tsaddr.ExitRoutes(), nil)
 	if err != nil {
-		return fmt.Errorf("Couldn't check system's IP forwarding configuration, subnet routing/exit nodes may not work: %w%s", err, kbLink)
+		return err
 	}
-
-	if len(disabled) == 0 {
-		// IP forwarding is enabled systemwide, all is well.
-		return nil
-	}
-
-	// IP forwarding isn't enabled globally, but it might be enabled
-	// on a per-interface basis. Check if it's on for all interfaces,
-	// and warn appropriately if it's not.
-	ifaces, err := interfaces.GetList()
-	if err != nil {
-		return fmt.Errorf("Couldn't enumerate network interfaces, subnet routing/exit nodes may not work: %w%s", err, kbLink)
-	}
-
-	var (
-		warnings   []string
-		anyEnabled bool
-	)
-	for _, iface := range ifaces {
-		if iface.Name == "lo" {
-			continue
-		}
-		disabled, err = disabledSysctls(fmt.Sprintf("net.ipv4.conf.%s.forwarding", iface.Name), fmt.Sprintf("net.ipv6.conf.%s.forwarding", iface.Name))
-		if err != nil {
-			return fmt.Errorf("Couldn't check system's IP forwarding configuration, subnet routing/exit nodes may not work: %w%s", err, kbLink)
-		}
-		if len(disabled) > 0 {
-			warnings = append(warnings, fmt.Sprintf("Traffic received on %s won't be forwarded (%s disabled)", iface.Name, strings.Join(disabled, ", ")))
-		} else {
-			anyEnabled = true
-		}
-	}
-	if !anyEnabled {
-		// IP forwarding is compeltely disabled, just say that rather
-		// than enumerate all the interfaces on the system.
-		return fmt.Errorf("IP forwarding is disabled, subnet routing/exit nodes will not work.%s", kbLink)
-	}
-	if len(warnings) > 0 {
-		// If partially enabled, enumerate the bits that won't work.
-		return fmt.Errorf("%s\nSubnet routes and exit nodes may not work correctly.%s", strings.Join(warnings, "\n"), kbLink)
-	}
-
-	return nil
-}
-
-// disabledSysctls checks if the given sysctl keys are off, according
-// to strconv.ParseBool. Returns a list of keys that are disabled, or
-// err if something went wrong which prevented the lookups from
-// completing.
-func disabledSysctls(sysctls ...string) (disabled []string, err error) {
-	for _, k := range sysctls {
-		// TODO: on linux, we can get at these values via /proc/sys,
-		// rather than fork subcommands that may not be installed.
-		bs, err := exec.Command("sysctl", "-n", k).Output()
-		if err != nil {
-			return nil, fmt.Errorf("couldn't check %s (%v)", k, err)
-		}
-		on, err := strconv.ParseBool(string(bytes.TrimSpace(bs)))
-		if err != nil {
-			return nil, fmt.Errorf("couldn't parse %s (%v)", k, err)
-		}
-		if !on {
-			disabled = append(disabled, k)
-		}
-	}
-	return disabled, nil
+	return warn
 }
 
 // DERPMap returns the current DERPMap in use, or nil if not connected.
@@ -3157,6 +3152,15 @@ func (b *LocalBackend) allowExitNodeDNSProxyToServeName(name string) bool {
 	return true
 }
 
+// SetExpiry updates the expiry of the current node key to t, as long as it's
+// only sooner than the old expiry.
+//
+// If t is in the past, the key is expired immediately.
+// If t is after the current expiry, an error is returned.
+func (b *LocalBackend) SetExpirySooner(ctx context.Context, expiry time.Time) error {
+	return b.cc.SetExpirySooner(ctx, expiry)
+}
+
 // exitNodeCanProxyDNS reports the DoH base URL ("http://foo/dns-query") without query parameters
 // to exitNodeID's DoH service, if available.
 //
@@ -3169,7 +3173,9 @@ func exitNodeCanProxyDNS(nm *netmap.NetworkMap, exitNodeID tailcfg.StableNodeID)
 		if p.StableID != exitNodeID {
 			continue
 		}
-		for _, s := range p.Hostinfo.Services {
+		services := p.Hostinfo.Services()
+		for i, n := 0, services.Len(); i < n; i++ {
+			s := services.At(i)
 			if s.Proto == tailcfg.PeerAPIDNS && s.Port >= 1 {
 				return peerAPIBase(nm, p) + "/dns-query", true
 			}
@@ -3207,3 +3213,15 @@ func (b *LocalBackend) magicConn() (*magicsock.Conn, error) {
 	}
 	return mc, nil
 }
+
+// DoNoiseRequest sends a request to URL over the the control plane
+// Noise connection.
+func (b *LocalBackend) DoNoiseRequest(req *http.Request) (*http.Response, error) {
+	b.mu.Lock()
+	cc := b.cc
+	b.mu.Unlock()
+	if cc == nil {
+		return nil, errors.New("no client")
+	}
+	return cc.DoNoiseRequest(req)
+}

ipn/ipnlocal/local_test.go

@@ -14,6 +14,7 @@ import (
 
 	"inet.af/netaddr"
 	"tailscale.com/ipn"
+	"tailscale.com/ipn/store/mem"
 	"tailscale.com/net/interfaces"
 	"tailscale.com/net/tsaddr"
 	"tailscale.com/tailcfg"
@@ -301,8 +302,31 @@ func TestPeerRoutes(t *testing.T) {
 				},
 			},
 			want: []netaddr.IPPrefix{
-				pp("fd7a:115c:a1e0::/48"),
 				pp("100.64.0.0/10"),
+				pp("fd7a:115c:a1e0::/48"),
+			},
+		},
+		{
+			name: "output-should-be-sorted",
+			peers: []wgcfg.Peer{
+				{
+					AllowedIPs: []netaddr.IPPrefix{
+						pp("100.64.0.2/32"),
+						pp("10.0.0.0/16"),
+					},
+				},
+				{
+					AllowedIPs: []netaddr.IPPrefix{
+						pp("100.64.0.1/32"),
+						pp("10.0.0.0/8"),
+					},
+				},
+			},
+			want: []netaddr.IPPrefix{
+				pp("10.0.0.0/8"),
+				pp("10.0.0.0/16"),
+				pp("100.64.0.1/32"),
+				pp("100.64.0.2/32"),
 			},
 		},
 	}
@@ -346,12 +370,12 @@ func TestPeerAPIBase(t *testing.T) {
 					netaddr.MustParseIPPrefix("100.64.1.2/32"),
 					netaddr.MustParseIPPrefix("fe70::2/128"),
 				},
-				Hostinfo: tailcfg.Hostinfo{
+				Hostinfo: (&tailcfg.Hostinfo{
 					Services: []tailcfg.Service{
 						{Proto: "peerapi4", Port: 444},
 						{Proto: "peerapi6", Port: 666},
 					},
-				},
+				}).View(),
 			},
 			want: "http://100.64.1.2:444",
 		},
@@ -367,12 +391,12 @@ func TestPeerAPIBase(t *testing.T) {
 					netaddr.MustParseIPPrefix("100.64.1.2/32"),
 					netaddr.MustParseIPPrefix("fe70::2/128"),
 				},
-				Hostinfo: tailcfg.Hostinfo{
+				Hostinfo: (&tailcfg.Hostinfo{
 					Services: []tailcfg.Service{
 						{Proto: "peerapi4", Port: 444},
 						{Proto: "peerapi6", Port: 666},
 					},
-				},
+				}).View(),
 			},
 			want: "http://[fe70::2]:666",
 		},
@@ -389,11 +413,11 @@ func TestPeerAPIBase(t *testing.T) {
 					netaddr.MustParseIPPrefix("100.64.1.2/32"),
 					netaddr.MustParseIPPrefix("fe70::2/128"),
 				},
-				Hostinfo: tailcfg.Hostinfo{
+				Hostinfo: (&tailcfg.Hostinfo{
 					Services: []tailcfg.Service{
 						{Proto: "peerapi4", Port: 444},
 					},
-				},
+				}).View(),
 			},
 			want: "http://100.64.1.2:444",
 		},
@@ -410,11 +434,11 @@ func TestPeerAPIBase(t *testing.T) {
 					netaddr.MustParseIPPrefix("100.64.1.2/32"),
 					netaddr.MustParseIPPrefix("fe70::2/128"),
 				},
-				Hostinfo: tailcfg.Hostinfo{
+				Hostinfo: (&tailcfg.Hostinfo{
 					Services: []tailcfg.Service{
 						{Proto: "peerapi6", Port: 666},
 					},
-				},
+				}).View(),
 			},
 			want: "http://[fe70::2]:666",
 		},
@@ -457,13 +481,13 @@ func TestLazyMachineKeyGeneration(t *testing.T) {
 	panicOnMachineKeyGeneration = true
 
 	var logf logger.Logf = logger.Discard
-	store := new(ipn.MemoryStore)
+	store := new(mem.Store)
 	eng, err := wgengine.NewFakeUserspaceEngine(logf, 0)
 	if err != nil {
 		t.Fatalf("NewFakeUserspaceEngine: %v", err)
 	}
 	t.Cleanup(eng.Close)
-	lb, err := NewLocalBackend(logf, "logid", store, nil, eng)
+	lb, err := NewLocalBackend(logf, "logid", store, nil, eng, 0)
 	if err != nil {
 		t.Fatalf("NewLocalBackend: %v", err)
 	}

ipn/ipnlocal/loglines_test.go

@@ -11,6 +11,7 @@ import (
 
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/ipn/store/mem"
 	"tailscale.com/logtail"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tstest"
@@ -47,14 +48,14 @@ func TestLocalLogLines(t *testing.T) {
 	idA := logid(0xaa)
 
 	// set up a LocalBackend, super bare bones. No functional data.
-	store := &ipn.MemoryStore{}
+	store := new(mem.Store)
 	e, err := wgengine.NewFakeUserspaceEngine(logf, 0)
 	if err != nil {
 		t.Fatal(err)
 	}
 	t.Cleanup(e.Close)
 
-	lb, err := NewLocalBackend(logf, idA.String(), store, nil, e)
+	lb, err := NewLocalBackend(logf, idA.String(), store, nil, e, 0)
 	if err != nil {
 		t.Fatal(err)
 	}

ipn/ipnlocal/peerapi.go

@@ -38,6 +38,7 @@ import (
 	"tailscale.com/logtail/backoff"
 	"tailscale.com/net/dns/resolver"
 	"tailscale.com/net/interfaces"
+	"tailscale.com/net/netutil"
 	"tailscale.com/syncs"
 	"tailscale.com/tailcfg"
 	"tailscale.com/util/clientmetric"
@@ -410,7 +411,7 @@ func (s *peerAPIServer) listen(ip netaddr.IP, ifState *interfaces.State) (ln net
 	}
 
 	// Make a best effort to pick a deterministic port number for
-	// the ip The lower three bytes are the same for IPv4 and IPv6
+	// the ip. The lower three bytes are the same for IPv4 and IPv6
 	// Tailscale addresses (at least currently), so we'll usually
 	// get the same port number on both address families for
 	// dev/debugging purposes, which is nice. But it's not so
@@ -506,27 +507,9 @@ func (pln *peerAPIListener) ServeConn(src netaddr.IPPort, c net.Conn) {
 	if addH2C != nil {
 		addH2C(httpServer)
 	}
-	go httpServer.Serve(&oneConnListener{Listener: pln.ln, conn: c})
+	go httpServer.Serve(netutil.NewOneConnListener(c, pln.ln.Addr()))
 }
 
-type oneConnListener struct {
-	net.Listener
-	conn net.Conn
-}
-
-func (l *oneConnListener) Accept() (c net.Conn, err error) {
-	c = l.conn
-	if c == nil {
-		err = io.EOF
-		return
-	}
-	err = nil
-	l.conn = nil
-	return
-}
-
-func (l *oneConnListener) Close() error { return nil }
-
 // peerAPIHandler serves the Peer API for a source specific client.
 type peerAPIHandler struct {
 	ps         *peerAPIServer
@@ -536,7 +519,7 @@ type peerAPIHandler struct {
 	peerUser   tailcfg.UserProfile // profile of peerNode
 }
 
-func (h *peerAPIHandler) logf(format string, a ...interface{}) {
+func (h *peerAPIHandler) logf(format string, a ...any) {
 	h.ps.b.logf("peerapi: "+format, a...)
 }
 

ipn/ipnlocal/ssh.go

@@ -0,0 +1,142 @@
+// 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 && !ios)
+// +build linux darwin,!ios
+
+package ipnlocal
+
+import (
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	"github.com/tailscale/golang-x-crypto/ssh"
+	"tailscale.com/envknob"
+)
+
+var useHostKeys = envknob.Bool("TS_USE_SYSTEM_SSH_HOST_KEYS")
+
+// keyTypes are the SSH key types that we either try to read from the
+// system's OpenSSH keys or try to generate for ourselves when not
+// running as root.
+var keyTypes = []string{"rsa", "ecdsa", "ed25519"}
+
+func (b *LocalBackend) GetSSH_HostKeys() (keys []ssh.Signer, err error) {
+	if os.Geteuid() == 0 {
+		keys, err = b.getSystemSSH_HostKeys()
+		if err != nil || len(keys) > 0 {
+			return keys, err
+		}
+		// Otherwise, perhaps they don't have OpenSSH etc installed.
+		// Generate our own keys...
+	}
+	return b.getTailscaleSSH_HostKeys()
+}
+
+func (b *LocalBackend) getTailscaleSSH_HostKeys() (keys []ssh.Signer, err error) {
+	root := b.TailscaleVarRoot()
+	if root == "" {
+		return nil, errors.New("no var root for ssh keys")
+	}
+	keyDir := filepath.Join(root, "ssh")
+	if err := os.MkdirAll(keyDir, 0700); err != nil {
+		return nil, err
+	}
+	for _, typ := range keyTypes {
+		hostKey, err := b.hostKeyFileOrCreate(keyDir, typ)
+		if err != nil {
+			return nil, err
+		}
+		signer, err := ssh.ParsePrivateKey(hostKey)
+		if err != nil {
+			return nil, err
+		}
+		keys = append(keys, signer)
+	}
+	return keys, nil
+}
+
+var keyGenMu sync.Mutex
+
+func (b *LocalBackend) hostKeyFileOrCreate(keyDir, typ string) ([]byte, error) {
+	keyGenMu.Lock()
+	defer keyGenMu.Unlock()
+
+	path := filepath.Join(keyDir, "ssh_host_"+typ+"_key")
+	v, err := ioutil.ReadFile(path)
+	if err == nil {
+		return v, nil
+	}
+	if !os.IsNotExist(err) {
+		return nil, err
+	}
+	var priv any
+	switch typ {
+	default:
+		return nil, fmt.Errorf("unsupported key type %q", typ)
+	case "ed25519":
+		_, priv, err = ed25519.GenerateKey(rand.Reader)
+	case "ecdsa":
+		// curve is arbitrary. We pick whatever will at
+		// least pacify clients as the actual encryption
+		// doesn't matter: it's all over WireGuard anyway.
+		curve := elliptic.P256()
+		priv, err = ecdsa.GenerateKey(curve, rand.Reader)
+	case "rsa":
+		// keySize is arbitrary. We pick whatever will at
+		// least pacify clients as the actual encryption
+		// doesn't matter: it's all over WireGuard anyway.
+		const keySize = 2048
+		priv, err = rsa.GenerateKey(rand.Reader, keySize)
+	}
+	if err != nil {
+		return nil, err
+	}
+	mk, err := x509.MarshalPKCS8PrivateKey(priv)
+	if err != nil {
+		return nil, err
+	}
+	pemGen := pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: mk})
+	err = os.WriteFile(path, pemGen, 0700)
+	return pemGen, err
+}
+
+func (b *LocalBackend) getSystemSSH_HostKeys() (ret []ssh.Signer, err error) {
+	// TODO(bradfitz): cache this?
+	for _, typ := range keyTypes {
+		hostKey, err := ioutil.ReadFile("/etc/ssh/ssh_host_" + typ + "_key")
+		if os.IsNotExist(err) {
+			continue
+		}
+		if err != nil {
+			return nil, err
+		}
+		signer, err := ssh.ParsePrivateKey(hostKey)
+		if err != nil {
+			return nil, err
+		}
+		ret = append(ret, signer)
+	}
+	return ret, nil
+}
+
+func (b *LocalBackend) getSSHHostKeyPublicStrings() (ret []string) {
+	signers, _ := b.GetSSH_HostKeys()
+	for _, signer := range signers {
+		ret = append(ret, strings.TrimSpace(string(ssh.MarshalAuthorizedKey(signer.PublicKey()))))
+	}
+	return ret
+}