wgengine/netstack: forward incoming connections to localhost

Updates #707
Updates #504

Signed-off-by: Naman Sood <mail@nsood.in>

.github/workflows/coverage.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
       id: go
 
     - name: Check out code into the Go module directory

.github/workflows/cross-darwin.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
       id: go
 
     - name: Check out code into the Go module directory

.github/workflows/cross-freebsd.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
       id: go
 
     - name: Check out code into the Go module directory

.github/workflows/cross-openbsd.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
       id: go
 
     - name: Check out code into the Go module directory

.github/workflows/cross-windows.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
       id: go
 
     - name: Check out code into the Go module directory

.github/workflows/depaware.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
 
     - name: Check out code
       uses: actions/checkout@v1

.github/workflows/license.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
 
     - name: Check out code
       uses: actions/checkout@v1

.github/workflows/linux.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
       id: go
 
     - name: Check out code into the Go module directory

.github/workflows/linux32.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
       id: go
 
     - name: Check out code into the Go module directory

.github/workflows/staticcheck.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.15
+        go-version: 1.16
 
     - name: Check out code
       uses: actions/checkout@v1

.github/workflows/windows.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Install Go
       uses: actions/setup-go@v2
       with:
-        go-version: 1.15.x
+        go-version: 1.16.x
 
     - name: Checkout code
       uses: actions/checkout@v2

Dockerfile

@@ -38,7 +38,7 @@
 #     $ docker exec tailscaled tailscale status
 
 
-FROM golang:1.15-alpine AS build-env
+FROM golang:1.16-alpine AS build-env
 
 WORKDIR /go/src/tailscale
 
@@ -48,6 +48,10 @@ RUN go mod download
 
 COPY . .
 
+# see build_docker.sh
+ARG goflags_arg=""
+ENV GOFLAGS=$goflags_arg
+
 RUN go install -v ./cmd/...
 
 FROM alpine:3.11

LICENSE

@@ -1,27 +1,29 @@
-Copyright (c) 2020 Tailscale & AUTHORS. All rights reserved.
+BSD 3-Clause License
+
+Copyright (c) 2020 Tailscale & AUTHORS.
+All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
+modification, are permitted provided that the following conditions are met:
 
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Tailscale Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
 
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Makefile

@@ -12,7 +12,13 @@ depaware:
 	go run github.com/tailscale/depaware --check tailscale.com/cmd/tailscaled
 	go run github.com/tailscale/depaware --check tailscale.com/cmd/tailscale
 
-check: staticcheck vet depaware
+buildwindows:
+	GOOS=windows GOARCH=amd64 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
+
+check: staticcheck vet depaware buildwindows build386
 
 staticcheck:
 	go run honnef.co/go/tools/cmd/staticcheck -- $$(go list ./... | grep -v tempfork)

README.md

@@ -43,7 +43,7 @@ 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 1.15) in module mode. It might
+release candidate builds (currently Go 1.16) 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 @@
-1.3.0
+1.5.0

api.md

@@ -5,7 +5,28 @@ The Tailscale API is a (mostly) RESTful API. Typically, POST bodies should be JS
 # Authentication
 Currently based on {some authentication method}. Visit the [admin panel](https://api.tailscale.com/admin) and navigate to the `Keys` page. Generate an API Key and keep it safe. Provide the key as the user key in basic auth when making calls to Tailscale API endpoints.
 
-# APIS
+# APIs
+
+* **[Devices](#device)**
+  - [GET device](#device-get)
+  - [DELETE device](#device-delete)
+  - Routes
+    - [GET device routes](#device-routes-get)
+    - [POST device routes](#device-routes-post)
+* **[Tailnets](#tailnet)**
+  - ACLs
+    - [GET tailnet ACL](#tailnet-acl-get)
+    - [POST tailnet ACL](#tailnet-acl-post): set ACL for a tailnet
+    - [POST tailnet ACL preview](#tailnet-acl-preview-post): preview rule matches on an ACL for a resource
+  - [Devices](#tailnet-devices)
+    - [GET tailnet devices](#tailnet-devices-get)
+  - [DNS](#tailnet-dns)
+    - [GET tailnet DNS nameservers](#tailnet-dns-nameservers-get)
+    - [POST tailnet DNS nameservers](#tailnet-dns-nameservers-post)
+    - [GET tailnet DNS preferences](#tailnet-dns-preferences-get)
+    - [POST tailnet DNS preferences](#tailnet-dns-preferences-post)
+    - [GET tailnet DNS searchpaths](#tailnet-dns-searchpaths-get)
+    - [POST tailnet DNS searchpaths](#tailnet-dns-searchpaths-post)
 
 ## Device
 <!-- TODO: description about what devices are -->
@@ -16,6 +37,8 @@ To find the deviceID of a particular device, you can use the ["GET /devices"](#g
 Find the device you're looking for and get the "id" field.
 This is your deviceID. 
 
+<a name=device-get></div>
+
 #### `GET /api/v2/device/:deviceid` - lists the details for a device
 Returns the details for the specified device.
 Supply the device of interest in the path using its ID.
@@ -103,6 +126,7 @@ Response
 }
 ```
 
+<a name=device-delete></div>
 
 #### `DELETE /api/v2/device/:deviceID` - deletes the device from its tailnet
 Deletes the provided device from its tailnet. 
@@ -139,6 +163,8 @@ If the device is not owned by your tailnet:
 ```
 
 
+<a name=device-routes-get></div>
+
 #### `GET /api/v2/device/:deviceID/routes` - fetch subnet routes that are advertised and enabled for a device
 
 Retrieves the list of subnet routes that a device is advertising, as well as those that are enabled for it. Enabled routes are not necessarily advertised (e.g. for pre-enabling), and likewise, advertised routes are not necessarily enabled.
@@ -166,6 +192,8 @@ Response
 }
 ```
 
+<a name=device-routes-post></div>
+
 #### `POST /api/v2/device/:deviceID/routes` - set the subnet routes that are enabled for a device
 
 Sets which subnet routes are enabled to be routed by a device by replacing the existing list of subnet routes with the supplied parameters. Routes can be enabled without a device advertising them (e.g. for preauth). Returns a list of enabled subnet routes and a list of advertised subnet routes for a device.
@@ -210,7 +238,8 @@ A tailnet is the name of your Tailscale network.
 You can find it in the top left corner of the [Admin Panel](https://login.tailscale.com/admin) beside the Tailscale logo.
 
 
-"alice@example.com" belongs to the "example.com" tailnet and would use the following format for API calls:
+`alice@example.com` belongs to the `example.com` tailnet and would use the following format for API calls:
+
 ```
 GET /api/v2/tailnet/example.com/...
 curl https://api.tailscale.com/api/v2/tailnet/example.com/...
@@ -218,21 +247,21 @@ curl https://api.tailscale.com/api/v2/tailnet/example.com/...
 
 
 For solo plans, the tailnet is the email you signed up with.
-So "alice@gmail.com" has the tailnet "alice@gmail.com" since @gmail.com is a shared email host.
+So `alice@gmail.com` has the tailnet `alice@gmail.com` since `@gmail.com` is a shared email host.
 Her API calls would have the following format:
 ```
 GET /api/v2/tailnet/alice@gmail.com/...
 curl https://api.tailscale.com/api/v2/tailnet/alice@gmail.com/...
 ```
 
-Tailnets are a top level resource. ACL is an example of a resource that is tied to a top level tailnet.
-
+Tailnets are a top-level resource. ACL is an example of a resource that is tied to a top-level tailnet.
 
 For more information on Tailscale networks/tailnets, click [here](https://tailscale.com/kb/1064/invite-team-members).
 
-
 ### ACL
 
+<a name=tailnet-acl-get></a>
+
 #### `GET /api/v2/tailnet/:tailnet/acl` - fetch ACL for a tailnet
 
 Retrieves the ACL that is currently set for the given tailnet. Supply the tailnet of interest in the path. This endpoint can send back either the HuJSON of the ACL or a parsed JSON, depending on the `Accept` header.
@@ -334,6 +363,8 @@ Etag: "e0b2816b418b3f266309d94426ac7668ab3c1fa87798785bf82f1085cc2f6d9c"
 }
 ```
 
+<a name=tailnet-acl-post></a>
+
 #### `POST /api/v2/tailnet/:tailnet/acl` - set ACL for a tailnet
 
 Sets the ACL for the given tailnet. HuJSON and JSON are both accepted inputs. An `If-Match` header can be set to avoid missed updates.
@@ -405,6 +436,8 @@ Response
 }
 ```
 
+<a name=tailnet-acl-preview-post></a>
+
 #### `POST /api/v2/tailnet/:tailnet/acl/preview` - preview rule matches on an ACL for a resource
 Determines what rules match for a user on an ACL without saving the ACL to the server.
 
@@ -449,8 +482,12 @@ Response
 {"matches":[{"users":["*"],"ports":["*:*"],"lineNumber":19}],"user":"user1@example.com"}
 ```
 
+<a name=tailnet-devices></a>
+
 ### Devices
 
+<a name=tailnet-devices-get></a>
+
 #### <a name="getdevices"></a> `GET /api/v2/tailnet/:tailnet/devices` - list the devices for a tailnet
 Lists the devices in a tailnet. 
 Supply the tailnet of interest in the path.
@@ -531,9 +568,12 @@ Response
 }
 ```
 
+<a name=tailnet-dns></a>
 
 ### DNS
 
+<a name=tailnet-dns-nameservers-get></a>
+
 #### `GET /api/v2/tailnet/:tailnet/dns/nameservers` - list the DNS nameservers for a tailnet
 Lists the DNS nameservers for a tailnet. 
 Supply the tailnet of interest in the path.
@@ -556,6 +596,8 @@ Response
 }
 ```
 
+<a name=tailnet-dns-nameservers-post></a>
+
 #### `POST /api/v2/tailnet/:tailnet/dns/nameservers` - replaces the list of DNS nameservers for a tailnet
 Replaces the list of DNS nameservers for the given tailnet with the list supplied by the user. 
 Supply the tailnet of interest in the path.
@@ -608,6 +650,8 @@ Response:
 }
 ```
 
+<a name=tailnet-dns-preferences-get></a>
+
 #### `GET /api/v2/tailnet/:tailnet/dns/preferences` - retrieves the DNS preferences for a tailnet
 Retrieves the DNS preferences that are currently set for the given tailnet.
 Supply the tailnet of interest in the path.
@@ -629,6 +673,8 @@ Response:
 }
 ```
 
+<a name=tailnet-dns-preferences-post></a>
+
 #### `POST /api/v2/tailnet/:tailnet/dns/preferences` - replaces the DNS preferences for a tailnet 
 Replaces the DNS preferences for a tailnet, specifically, the MagicDNS setting.
 Note that MagicDNS is dependent on DNS servers. 
@@ -673,6 +719,8 @@ If there are DNS servers:
 }
 ```
 
+<a name=tailnet-dns-searchpaths-get></a>
+
 #### `GET /api/v2/tailnet/:tailnet/dns/searchpaths` - retrieves the search paths for a tailnet 
 Retrieves the list of search paths that is currently set for the given tailnet. 
 Supply the tailnet of interest in the path.
@@ -695,6 +743,8 @@ Response:
 }
 ```
 
+<a name=tailnet-dns-searchpaths-post></a>
+
 #### `POST /api/v2/tailnet/:tailnet/dns/searchpaths` - replaces the search paths for a tailnet 
 Replaces the list of searchpaths with the list supplied by the user and returns an error otherwise.
 

build_docker.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env sh
+
+#
+# Runs `go build` with flags configured for docker distribution. All
+# it does differently from `go build` is burn git commit and version
+# information into the binaries inside docker, so that we can track down user
+# issues.
+#
+############################################################################
+#
+# WARNING: Tailscale is not yet officially supported in Docker,
+# Kubernetes, etc.
+#
+# It might work, but we don't regularly test it, and it's not as polished as
+# our currently supported platforms. This is provided for people who know
+# how Tailscale works and what they're doing.
+#
+# Our tracking bug for officially support container use cases is:
+#    https://github.com/tailscale/tailscale/issues/504
+#
+# Also, see the various bugs tagged "containers":
+#    https://github.com/tailscale/tailscale/labels/containers
+#
+############################################################################
+
+set -eu
+
+eval $(./version/version.sh)
+
+GOFLAGS='-tags xversion -ldflags '"-X tailscale.com/version.Long=${VERSION_LONG} -X tailscale.com/version.Short=${VERSION_SHORT} -X tailscale.com/version.GitCommit=${VERSION_GIT_HASH}"
+docker build --build-arg goflags_arg="'""${GOFLAGS}""'" -t tailscale:tailscale .

client/tailscale/tailscale.go

@@ -0,0 +1,90 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package tailscale contains Tailscale client code.
+package tailscale
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/url"
+	"strconv"
+
+	"tailscale.com/safesocket"
+	"tailscale.com/tailcfg"
+)
+
+// tsClient does HTTP requests to the local Tailscale daemon.
+var tsClient = &http.Client{
+	Transport: &http.Transport{
+		DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+			if addr != "local-tailscaled.sock:80" {
+				return nil, fmt.Errorf("unexpected URL address %q", addr)
+			}
+			// On macOS, when dialing from non-sandboxed program to sandboxed GUI running
+			// a TCP server on a random port, find the random port. For HTTP connections,
+			// we don't send the token. It gets added in an HTTP Basic-Auth header.
+			if port, _, err := safesocket.LocalTCPPortAndToken(); err == nil {
+				var d net.Dialer
+				return d.DialContext(ctx, "tcp", "localhost:"+strconv.Itoa(port))
+			}
+			return safesocket.ConnectDefault()
+		},
+	},
+}
+
+// DoLocalRequest makes an HTTP request to the local machine's Tailscale daemon.
+//
+// URLs are of the form http://local-tailscaled.sock/localapi/v0/whois?ip=1.2.3.4.
+//
+// The hostname must be "local-tailscaled.sock", even though it
+// doesn't actually do any DNS lookup. The actual means of connecting to and
+// authenticating to the local Tailscale daemon vary by platform.
+//
+// DoLocalRequest may mutate the request to add Authorization headers.
+func DoLocalRequest(req *http.Request) (*http.Response, error) {
+	if _, token, err := safesocket.LocalTCPPortAndToken(); err == nil {
+		req.SetBasicAuth("", token)
+	}
+	return tsClient.Do(req)
+}
+
+// WhoIs returns the owner of the remoteAddr, which must be an IP or IP:port.
+func WhoIs(ctx context.Context, remoteAddr string) (*tailcfg.WhoIsResponse, error) {
+	var ip string
+	if net.ParseIP(remoteAddr) != nil {
+		ip = remoteAddr
+	} else {
+		var err error
+		ip, _, err = net.SplitHostPort(remoteAddr)
+		if err != nil {
+			return nil, fmt.Errorf("invalid remoteAddr %q", remoteAddr)
+		}
+	}
+	req, err := http.NewRequestWithContext(ctx, "GET", "http://local-tailscaled.sock/localapi/v0/whois?ip="+url.QueryEscape(ip), nil)
+	if err != nil {
+		return nil, err
+	}
+	res, err := DoLocalRequest(req)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	slurp, _ := ioutil.ReadAll(res.Body)
+	if res.StatusCode != 200 {
+		return nil, fmt.Errorf("HTTP %s: %s", res.Status, slurp)
+	}
+	r := new(tailcfg.WhoIsResponse)
+	if err := json.Unmarshal(slurp, r); err != nil {
+		if max := 200; len(slurp) > max {
+			slurp = slurp[:max]
+		}
+		return nil, fmt.Errorf("failed to parse JSON WhoIsResponse from %q", slurp)
+	}
+	return r, nil
+}

cmd/derper/bootstrap_dns.go

@@ -0,0 +1,69 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"expvar"
+	"log"
+	"net"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+)
+
+var (
+	dnsMu    sync.Mutex
+	dnsCache = map[string][]net.IP{}
+)
+
+var bootstrapDNSRequests = expvar.NewInt("counter_bootstrap_dns_requests")
+
+func refreshBootstrapDNSLoop() {
+	if *bootstrapDNS == "" {
+		return
+	}
+	for {
+		refreshBootstrapDNS()
+		time.Sleep(10 * time.Minute)
+	}
+}
+
+func refreshBootstrapDNS() {
+	if *bootstrapDNS == "" {
+		return
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+	names := strings.Split(*bootstrapDNS, ",")
+	var r net.Resolver
+	for _, name := range names {
+		addrs, err := r.LookupIP(ctx, "ip", name)
+		if err != nil {
+			log.Printf("bootstrap DNS lookup %q: %v", name, err)
+			continue
+		}
+		dnsMu.Lock()
+		dnsCache[name] = addrs
+		dnsMu.Unlock()
+	}
+}
+
+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")
+	w.Write(j)
+}

cmd/derper/derper.go

@@ -48,6 +48,7 @@ var (
 	runSTUN       = flag.Bool("stun", false, "also run a STUN server")
 	meshPSKFile   = flag.String("mesh-psk-file", defaultMeshPSKFile(), "if non-empty, path to file containing the mesh pre-shared key file. It should contain some hex string; whitespace is trimmed.")
 	meshWith      = flag.String("mesh-with", "", "optional comma-separated list of hostnames to mesh with; the server's own hostname can be in the list")
+	bootstrapDNS  = flag.String("bootstrap-dns-names", "", "optional comma-separated list of hostnames to make available at /bootstrap-dns")
 )
 
 type config struct {
@@ -145,6 +146,8 @@ func main() {
 	// Create our own mux so we don't expose /debug/ stuff to the world.
 	mux := tsweb.NewMux(debugHandler(s))
 	mux.Handle("/derp", derphttp.Handler(s))
+	go refreshBootstrapDNSLoop()
+	mux.HandleFunc("/bootstrap-dns", handleBootstrapDNS)
 	mux.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "text/html; charset=utf-8")
 		w.WriteHeader(200)
@@ -153,7 +156,7 @@ func main() {
 <p>
   This is a
   <a href="https://tailscale.com/">Tailscale</a>
-  <a href="https://godoc.org/tailscale.com/derp">DERP</a>
+  <a href="https://pkg.go.dev/tailscale.com/derp">DERP</a>
   server.
 </p>
 `)

cmd/derper/mesh.go

@@ -5,6 +5,7 @@
 package main
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"log"
@@ -40,6 +41,6 @@ func startMeshWithHost(s *derp.Server, host string) error {
 	c.MeshKey = s.MeshKey()
 	add := func(k key.Public) { s.AddPacketForwarder(k, c) }
 	remove := func(k key.Public) { s.RemovePacketForwarder(k, c) }
-	go c.RunWatchConnectionLoop(s.PublicKey(), add, remove)
+	go c.RunWatchConnectionLoop(context.Background(), s.PublicKey(), logf, add, remove)
 	return nil
 }

cmd/hello/hello.go

@@ -0,0 +1,169 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The hello binary runs hello.ipn.dev.
+package main // import "tailscale.com/cmd/hello"
+
+import (
+	"context"
+	_ "embed"
+	"encoding/json"
+	"flag"
+	"html/template"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"strings"
+
+	"tailscale.com/client/tailscale"
+)
+
+var (
+	httpAddr  = flag.String("http", ":80", "address to run an HTTP server on, or empty for none")
+	httpsAddr = flag.String("https", ":443", "address to run an HTTPS server on, or empty for none")
+	testIP    = flag.String("test-ip", "", "if non-empty, look up IP and exit before running a server")
+)
+
+//go:embed hello.tmpl.html
+var embeddedTemplate string
+
+func main() {
+	flag.Parse()
+	if *testIP != "" {
+		res, err := tailscale.WhoIs(context.Background(), *testIP)
+		if err != nil {
+			log.Fatal(err)
+		}
+		e := json.NewEncoder(os.Stdout)
+		e.SetIndent("", "\t")
+		e.Encode(res)
+		return
+	}
+	if devMode() {
+		// Parse it optimistically
+		var err error
+		tmpl, err = template.New("home").Parse(embeddedTemplate)
+		if err != nil {
+			log.Printf("ignoring template error in dev mode: %v", err)
+		}
+	} else {
+		if embeddedTemplate == "" {
+			log.Fatalf("embeddedTemplate is empty; must be build with Go 1.16+")
+		}
+		tmpl = template.Must(template.New("home").Parse(embeddedTemplate))
+	}
+
+	http.HandleFunc("/", root)
+	log.Printf("Starting hello server.")
+
+	errc := make(chan error, 1)
+	if *httpAddr != "" {
+		log.Printf("running HTTP server on %s", *httpAddr)
+		go func() {
+			errc <- http.ListenAndServe(*httpAddr, nil)
+		}()
+	}
+	if *httpsAddr != "" {
+		log.Printf("running HTTPS server on %s", *httpsAddr)
+		go func() {
+			errc <- http.ListenAndServeTLS(*httpsAddr,
+				"/etc/hello/hello.ipn.dev.crt",
+				"/etc/hello/hello.ipn.dev.key",
+				nil,
+			)
+		}()
+	}
+	log.Fatal(<-errc)
+}
+
+func devMode() bool { return *httpsAddr == "" && *httpAddr != "" }
+
+func getTmpl() (*template.Template, error) {
+	if devMode() {
+		tmplData, err := ioutil.ReadFile("hello.tmpl.html")
+		if os.IsNotExist(err) {
+			log.Printf("using baked-in template in dev mode; can't find hello.tmpl.html in current directory")
+			return tmpl, nil
+		}
+		return template.New("home").Parse(string(tmplData))
+	}
+	return tmpl, nil
+}
+
+// tmpl is the template used in prod mode.
+// In dev mode it's only used if the template file doesn't exist on disk.
+// It's initialized by main after flag parsing.
+var tmpl *template.Template
+
+type tmplData struct {
+	DisplayName   string // "Foo Barberson"
+	LoginName     string // "foo@bar.com"
+	ProfilePicURL string // "https://..."
+	MachineName   string // "imac5k"
+	MachineOS     string // "Linux"
+	IP            string // "100.2.3.4"
+}
+
+func root(w http.ResponseWriter, r *http.Request) {
+	if r.TLS == nil && *httpsAddr != "" {
+		host := r.Host
+		if strings.Contains(r.Host, "100.101.102.103") {
+			host = "hello.ipn.dev"
+		}
+		http.Redirect(w, r, "https://"+host, http.StatusFound)
+		return
+	}
+	if r.RequestURI != "/" {
+		http.Redirect(w, r, "/", http.StatusFound)
+		return
+	}
+	tmpl, err := getTmpl()
+	if err != nil {
+		w.Header().Set("Content-Type", "text/plain")
+		http.Error(w, "template error: "+err.Error(), 500)
+		return
+	}
+
+	who, err := tailscale.WhoIs(r.Context(), r.RemoteAddr)
+	var data tmplData
+	if err != nil {
+		if devMode() {
+			log.Printf("warning: using fake data in dev mode due to whois lookup error: %v", err)
+			data = tmplData{
+				DisplayName:   "Taily Scalerson",
+				LoginName:     "taily@scaler.son",
+				ProfilePicURL: "https://placekitten.com/200/200",
+				MachineName:   "scaled",
+				MachineOS:     "Linux",
+				IP:            "100.1.2.3",
+			}
+		} else {
+			log.Printf("whois(%q) error: %v", r.RemoteAddr, err)
+			http.Error(w, "Your Tailscale works, but we failed to look you up.", 500)
+			return
+		}
+	} else {
+		ip, _, _ := net.SplitHostPort(r.RemoteAddr)
+		data = tmplData{
+			DisplayName:   who.UserProfile.DisplayName,
+			LoginName:     who.UserProfile.LoginName,
+			ProfilePicURL: who.UserProfile.ProfilePicURL,
+			MachineName:   firstLabel(who.Node.ComputedName),
+			MachineOS:     who.Node.Hostinfo.OS,
+			IP:            ip,
+		}
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	tmpl.Execute(w, data)
+}
+
+// firstLabel s up until the first period, if any.
+func firstLabel(s string) string {
+	if i := strings.Index(s, "."); i != -1 {
+		return s[:i]
+	}
+	return s
+}

cmd/hello/hello.tmpl.html

@@ -0,0 +1,436 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0">
+  <title>Hello from Tailscale</title>
+  <style>
+    html,
+    body {
+      margin: 0;
+      padding: 0;
+    }
+
+    body {
+      font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
+      font-size: 100%;
+      -webkit-font-smoothing: antialiased;
+      -moz-osx-font-smoothing: grayscale;
+    }
+
+    html,
+    body,
+    main {
+      height: 100%;
+    }
+
+    *,
+    ::before,
+    ::after {
+      box-sizing: border-box;
+      border-width: 0;
+      border-style: solid;
+      border-color: #dad6d5;
+    }
+
+    h1,
+    h2,
+    h3,
+    h4,
+    h5,
+    h6 {
+      margin: 0;
+      font-size: 1rem;
+      font-weight: inherit;
+    }
+
+    a {
+      color: inherit;
+    }
+
+    p {
+      margin: 0;
+    }
+
+    main {
+      display: flex;
+      flex-direction: column;
+      justify-content: center;
+      align-items: center;
+      max-width: 24rem;
+      width: 95%;
+      margin-left: auto;
+      margin-right: auto;
+    }
+
+    .p-2 {
+      padding: 0.5rem;
+    }
+
+    .p-4 {
+      padding: 1rem;
+    }
+
+    .px-2 {
+      padding-left: 0.5rem;
+      padding-right: 0.5rem;
+    }
+
+    .pl-3 {
+      padding-left: 0.75rem;
+    }
+
+    .pr-3 {
+      padding-right: 0.75rem;
+    }
+
+    .pt-4 {
+      padding-top: 1rem;
+    }
+
+    .mr-2 {
+      margin-right: 0.5rem;
+      ;
+    }
+
+    .mb-1 {
+      margin-bottom: 0.25rem;
+    }
+
+    .mb-2 {
+      margin-bottom: 0.5rem;
+    }
+
+    .mb-4 {
+      margin-bottom: 1rem;
+    }
+
+    .mb-6 {
+      margin-bottom: 1.5rem;
+    }
+
+    .mb-8 {
+      margin-bottom: 2rem;
+    }
+
+    .mb-12 {
+      margin-bottom: 3rem;
+    }
+
+    .width-full {
+      width: 100%;
+    }
+
+    .min-width-0 {
+      min-width: 0;
+    }
+
+    .rounded-lg {
+      border-radius: 0.5rem;
+    }
+
+    .relative {
+      position: relative;
+    }
+
+    .flex {
+      display: flex;
+    }
+
+    .justify-between {
+      justify-content: space-between;
+    }
+
+    .items-center {
+      align-items: center;
+    }
+
+    .border {
+      border-width: 1px;
+    }
+
+    .border-t-1 {
+      border-top-width: 1px;
+    }
+
+    .border-gray-100 {
+      border-color: #f7f5f4;
+    }
+
+    .border-gray-200 {
+      border-color: #eeebea;
+    }
+
+    .border-gray-300 {
+      border-color: #dad6d5;
+    }
+
+    .bg-white {
+      background-color: white;
+    }
+
+    .bg-gray-0 {
+      background-color: #faf9f8;
+    }
+
+    .bg-gray-100 {
+      background-color: #f7f5f4;
+    }
+
+    .text-green-600 {
+      color: #0d4b3b;
+    }
+
+    .text-blue-600 {
+      color: #3f5db3;
+    }
+
+    .hover\:text-blue-800:hover {
+      color: #253570;
+    }
+
+    .text-gray-600 {
+      color: #444342;
+    }
+
+    .text-gray-700 {
+      color: #2e2d2d;
+    }
+
+    .text-gray-800 {
+      color: #232222;
+    }
+
+    .text-center {
+      text-align: center;
+    }
+
+    .text-sm {
+      font-size: 0.875rem;
+    }
+
+    .font-title {
+      font-size: 1.25rem;
+      letter-spacing: -0.025em;
+    }
+
+    .font-semibold {
+      font-weight: 600;
+    }
+
+    .font-medium {
+      font-weight: 500;
+    }
+
+    .font-regular {
+      font-weight: 400;
+    }
+
+    .truncate {
+      overflow: hidden;
+      text-overflow: ellipsis;
+      white-space: nowrap;
+    }
+
+    .overflow-hidden {
+      overflow: hidden;
+    }
+
+    .profile-pic {
+      width: 2.5rem;
+      height: 2.5rem;
+      border-radius: 9999px;
+      background-size: cover;
+      margin-right: 0.5rem;
+      flex-shrink: 0;
+    }
+
+    .panel {
+      box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
+    }
+
+    .animate .panel {
+      transform: translateY(10%);
+      box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.0), 0 10px 10px -5px rgba(0, 0, 0, 0.0);
+      transition: transform 1200ms ease, opacity 1200ms ease, box-shadow 1200ms ease;
+    }
+
+    .animate .panel-interior {
+      opacity: 0.0;
+      transition: opacity 1200ms ease;
+    }
+
+    .animate .logo {
+      transform: translateY(2rem);
+      opacity: 0.0;
+      transition: transform 1200ms ease, opacity 1200ms ease;
+    }
+
+    .animate .header-title {
+      transform: translateY(1.6rem);
+      opacity: 0.0;
+      transition: transform 1200ms ease, opacity 1200ms ease;
+    }
+
+    .animate .header-text {
+      transform: translateY(1.2rem);
+      opacity: 0.0;
+      transition: transform 1200ms ease, opacity 1200ms ease;
+    }
+
+    .animate .footer {
+      transform: translateY(-0.5rem);
+      opacity: 0.0;
+      transition: transform 1200ms ease, opacity 1200ms ease;
+    }
+
+    .animating .panel {
+      transform: translateY(0);
+      opacity: 1.0;
+      box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
+    }
+
+    .animating .panel-interior {
+      opacity: 1.0;
+    }
+
+    .animating .spinner {
+      opacity: 0.0;
+    }
+
+    .animating .logo,
+    .animating .header-title,
+    .animating .header-text,
+    .animating .footer {
+      transform: translateY(0);
+      opacity: 1.0;
+    }
+
+    .spinner {
+      display: inline-flex;
+      position: absolute;
+      top: 50%;
+      left: 50%;
+      transform: translate(-50%, -50%);
+      align-items: center;
+      transition: opacity 200ms ease;
+    }
+
+    .spinner span {
+      display: inline-block;
+      background-color: currentColor;
+      border-radius: 9999px;
+      animation-name: loading-dots-blink;
+      animation-duration: 1.4s;
+      animation-iteration-count: infinite;
+      animation-fill-mode: both;
+      width: 0.35em;
+      height: 0.35em;
+      margin: 0 0.15em;
+    }
+
+    .spinner span:nth-child(2) {
+      animation-delay: 200ms;
+    }
+
+    .spinner span:nth-child(3) {
+      animation-delay: 400ms;
+    }
+
+    .spinner {
+      display: none;
+    }
+
+    .animate .spinner {
+      display: inline-flex;
+    }
+
+    @keyframes loading-dots-blink {
+      0% {
+        opacity: 0.2;
+      }
+      20% {
+        opacity: 1;
+      }
+      100% {
+        opacity: 0.2;
+      }
+    }
+
+    @media (prefers-reduced-motion) {
+      * {
+        animation-duration: 0ms !important;
+        transition-duration: 0ms !important;
+        transition-delay: 0ms !important;
+      }
+    }
+  </style>
+</head>
+<body class="bg-gray-100">
+  <script>
+    (function() {
+      var lastSeen = localStorage.getItem("lastSeen");
+      if (!lastSeen) {
+        document.body.classList.add("animate");
+        window.addEventListener("load", function () {
+          setTimeout(function () {
+            document.body.classList.add("animating");
+            localStorage.setItem("lastSeen", Date.now());
+          }, 100);
+        });
+      }
+    })();
+  </script>
+  <main class="text-gray-800">
+    <svg class="logo mb-6" width="28" height="28" viewBox="0 0 22 22" fill="none" xmlns="http://www.w3.org/2000/svg">
+      <circle opacity="0.2" cx="3.4" cy="3.25" r="2.7" fill="currentColor" />
+      <circle cx="3.4" cy="11.3" r="2.7" fill="currentColor" />
+      <circle opacity="0.2" cx="3.4" cy="19.5" r="2.7" fill="currentColor" />
+      <circle cx="11.5" cy="11.3" r="2.7" fill="currentColor" />
+      <circle cx="11.5" cy="19.5" r="2.7" fill="currentColor" />
+      <circle opacity="0.2" cx="11.5" cy="3.25" r="2.7" fill="currentColor" />
+      <circle opacity="0.2" cx="19.5" cy="3.25" r="2.7" fill="currentColor" />
+      <circle cx="19.5" cy="11.3" r="2.7" fill="currentColor" />
+      <circle opacity="0.2" cx="19.5" cy="19.5" r="2.7" fill="currentColor" />
+    </svg>
+    <header class="mb-8 text-center">
+      <h1 class="header-title font-title font-semibold mb-2">You're connected over Tailscale!</h1>
+      <p class="header-text">This device is signed in as…</p>
+    </header>
+    <div class="panel relative bg-white rounded-lg width-full shadow-xl mb-8 p-4">
+      <div class="spinner text-gray-600">
+        <span></span>
+        <span></span>
+        <span></span>
+      </div>
+      <div class="panel-interior flex items-center width-full min-width-0 p-2 mb-4">
+        <div class="profile-pic bg-gray-100" style="background-image: url({{.ProfilePicURL}});"></div>
+        <div class="overflow-hidden">
+          {{ with .DisplayName }}
+          <h4 class="font-semibold truncate">{{.}}</h4>
+          {{ end }}
+          <h5 class="text-gray-600 truncate">{{.LoginName}}</h5>
+        </div>
+      </div>
+      <div
+        class="panel-interior border border-gray-200 bg-gray-0 rounded-lg p-2 pl-3 pr-3 mb-2 width-full flex justify-between items-center">
+        <div class="flex items-center min-width-0">
+          <svg class="text-gray-600 mr-2" xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none"
+            stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+            <rect x="2" y="2" width="20" height="8" rx="2" ry="2"></rect>
+            <rect x="2" y="14" width="20" height="8" rx="2" ry="2"></rect>
+            <line x1="6" y1="6" x2="6.01" y2="6"></line>
+            <line x1="6" y1="18" x2="6.01" y2="18"></line>
+          </svg>
+          <h4 class="font-semibold truncate mr-2">{{.MachineName}}</h4>
+        </div>
+        <h5>{{.IP}}</h5>
+      </div>
+    </div>
+    <footer class="footer text-gray-600 text-center mb-12">
+      <p>Read about <a href="https://tailscale.com/kb/1017/install#advanced-features" class="text-blue-600 hover:text-blue-800"
+          target="_blank">what you can do next &rarr;</a></p>
+    </footer>
+  </main>
+</body>
+</html>

cmd/tailscale/cli/cli.go

@@ -68,11 +68,6 @@ change in the future.
 		Exec:    func(context.Context, []string) error { return flag.ErrHelp },
 	}
 
-	// Don't advertise the debug command, but it exists.
-	if strSliceContains(args, "debug") {
-		rootCmd.Subcommands = append(rootCmd.Subcommands, debugCmd)
-	}
-
 	if err := rootCmd.Parse(args); err != nil {
 		return err
 	}
@@ -134,12 +129,3 @@ func pump(ctx context.Context, bc *ipn.BackendClient, conn net.Conn) {
 		bc.GotNotifyMsg(msg)
 	}
 }
-
-func strSliceContains(ss []string, s string) bool {
-	for _, v := range ss {
-		if v == s {
-			return true
-		}
-	}
-	return false
-}

cmd/tailscale/cli/netcheck.go

@@ -18,6 +18,7 @@ import (
 	"github.com/peterbourgon/ff/v2/ffcli"
 	"tailscale.com/derp/derpmap"
 	"tailscale.com/net/netcheck"
+	"tailscale.com/net/portmapper"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/logger"
 )
@@ -43,7 +44,10 @@ var netcheckArgs struct {
 }
 
 func runNetcheck(ctx context.Context, args []string) error {
-	c := &netcheck.Client{}
+	c := &netcheck.Client{
+		UDPBindAddr: os.Getenv("TS_DEBUG_NETCHECK_UDP_BIND"),
+		PortMapper:  portmapper.NewClient(logger.WithPrefix(log.Printf, "portmap: ")),
+	}
 	if netcheckArgs.verbose {
 		c.Logf = logger.WithPrefix(log.Printf, "netcheck: ")
 		c.Verbose = true

cmd/tailscale/cli/ping.go

@@ -64,34 +64,63 @@ func runPing(ctx context.Context, args []string) error {
 	c, bc, ctx, cancel := connect(ctx)
 	defer cancel()
 
-	if len(args) != 1 {
+	if len(args) != 1 || args[0] == "" {
 		return errors.New("usage: ping <hostname-or-IP>")
 	}
-	hostOrIP := args[0]
 	var ip string
-	var res net.Resolver
-	if addrs, err := res.LookupHost(ctx, hostOrIP); err != nil {
-		return fmt.Errorf("error looking up IP of %q: %v", hostOrIP, err)
-	} else if len(addrs) == 0 {
-		return fmt.Errorf("no IPs found for %q", hostOrIP)
-	} else {
-		ip = addrs[0]
-	}
-	if pingArgs.verbose && ip != hostOrIP {
-		log.Printf("lookup %q => %q", hostOrIP, ip)
-	}
-
-	ch := make(chan *ipnstate.PingResult, 1)
+	prc := make(chan *ipnstate.PingResult, 1)
+	stc := make(chan *ipnstate.Status, 1)
 	bc.SetNotifyCallback(func(n ipn.Notify) {
 		if n.ErrMessage != nil {
 			log.Fatal(*n.ErrMessage)
 		}
 		if pr := n.PingResult; pr != nil && pr.IP == ip {
-			ch <- pr
+			prc <- pr
+		}
+		if n.Status != nil {
+			stc <- n.Status
 		}
 	})
 	go pump(ctx, bc, c)
 
+	hostOrIP := args[0]
+
+	// If the argument is an IP address, use it directly without any resolution.
+	if net.ParseIP(hostOrIP) != nil {
+		ip = hostOrIP
+	}
+
+	// Otherwise, try to resolve it first from the network peer list.
+	if ip == "" {
+		bc.RequestStatus()
+		select {
+		case st := <-stc:
+			for _, ps := range st.Peer {
+				if hostOrIP == dnsOrQuoteHostname(st, ps) || hostOrIP == ps.DNSName {
+					ip = ps.TailAddr
+					break
+				}
+			}
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+
+	// Finally, use DNS.
+	if ip == "" {
+		var res net.Resolver
+		if addrs, err := res.LookupHost(ctx, hostOrIP); err != nil {
+			return fmt.Errorf("error looking up IP of %q: %v", hostOrIP, err)
+		} else if len(addrs) == 0 {
+			return fmt.Errorf("no IPs found for %q", hostOrIP)
+		} else {
+			ip = addrs[0]
+		}
+	}
+	if pingArgs.verbose && ip != hostOrIP {
+		log.Printf("lookup %q => %q", hostOrIP, ip)
+	}
+
 	n := 0
 	anyPong := false
 	for {
@@ -101,7 +130,7 @@ func runPing(ctx context.Context, args []string) error {
 		select {
 		case <-timer.C:
 			fmt.Printf("timeout waiting for ping reply\n")
-		case pr := <-ch:
+		case pr := <-prc:
 			timer.Stop()
 			if pr.Err != "" {
 				return errors.New(pr.Err)

cmd/tailscale/cli/status.go

@@ -14,7 +14,6 @@ import (
 	"net"
 	"net/http"
 	"os"
-	"sort"
 	"strings"
 	"time"
 
@@ -66,7 +65,17 @@ func runStatus(ctx context.Context, args []string) error {
 			log.Fatal(*n.ErrMessage)
 		}
 		if n.Status != nil {
-			ch <- n.Status
+			select {
+			case ch <- n.Status:
+			default:
+				// A status update from somebody else's request.
+				// Ignoring this matters mostly for "tailscale status -web"
+				// mode, otherwise the channel send would block forever
+				// and pump would stop reading from tailscaled, which
+				// previously caused tailscaled to block (while holding
+				// a mutex), backing up unrelated clients.
+				// See https://github.com/tailscale/tailscale/issues/1234
+			}
 		}
 	})
 	go pump(ctx, bc, c)
@@ -150,13 +159,18 @@ func runStatus(ctx context.Context, args []string) error {
 		relay := ps.Relay
 		anyTraffic := ps.TxBytes != 0 || ps.RxBytes != 0
 		if !active {
-			if anyTraffic {
+			if ps.ExitNode {
+				f("idle; exit node")
+			} else if anyTraffic {
 				f("idle")
 			} else {
 				f("-")
 			}
 		} else {
 			f("active; ")
+			if ps.ExitNode {
+				f("exit node; ")
+			}
 			if relay != "" && ps.CurAddr == "" {
 				f("relay %q", relay)
 			} else if ps.CurAddr != "" {
@@ -181,7 +195,7 @@ func runStatus(ctx context.Context, args []string) error {
 			}
 			peers = append(peers, ps)
 		}
-		sort.Slice(peers, func(i, j int) bool { return sortKey(peers[i]) < sortKey(peers[j]) })
+		ipnstate.SortPeers(peers)
 		for _, ps := range peers {
 			active := peerActive(ps)
 			if statusArgs.active && !active {
@@ -202,23 +216,11 @@ func peerActive(ps *ipnstate.PeerStatus) bool {
 }
 
 func dnsOrQuoteHostname(st *ipnstate.Status, ps *ipnstate.PeerStatus) string {
-	if i := strings.Index(ps.DNSName, "."); i != -1 && dnsname.HasSuffix(ps.DNSName, st.MagicDNSSuffix) {
-		return ps.DNSName[:i]
+	baseName := dnsname.TrimSuffix(ps.DNSName, st.MagicDNSSuffix)
+	if baseName != "" {
+		return baseName
 	}
-	if ps.DNSName != "" {
-		return strings.TrimRight(ps.DNSName, ".")
-	}
-	return fmt.Sprintf("(%q)", strings.ReplaceAll(ps.SimpleHostName(), " ", "_"))
-}
-
-func sortKey(ps *ipnstate.PeerStatus) string {
-	if ps.DNSName != "" {
-		return ps.DNSName
-	}
-	if ps.HostName != "" {
-		return ps.HostName
-	}
-	return ps.TailAddr
+	return fmt.Sprintf("(%q)", dnsname.SanitizeHostname(ps.HostName))
 }
 
 func ownerLogin(st *ipnstate.Status, ps *ipnstate.PeerStatus) string {

cmd/tailscale/cli/up.go

@@ -14,6 +14,7 @@ import (
 	"os"
 	"os/exec"
 	"runtime"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -22,9 +23,9 @@ import (
 	"inet.af/netaddr"
 	"tailscale.com/ipn"
 	"tailscale.com/tailcfg"
+	"tailscale.com/types/preftype"
 	"tailscale.com/version"
 	"tailscale.com/version/distro"
-	"tailscale.com/wgengine/router"
 )
 
 var upCmd = &ffcli.Command{
@@ -45,6 +46,7 @@ specify any flags, options are reset to their default.
 		upf.BoolVar(&upArgs.acceptRoutes, "accept-routes", false, "accept routes advertised by other Tailscale nodes")
 		upf.BoolVar(&upArgs.acceptDNS, "accept-dns", true, "accept DNS configuration from the admin panel")
 		upf.BoolVar(&upArgs.singleRoutes, "host-routes", true, "install host routes to other Tailscale nodes")
+		upf.StringVar(&upArgs.exitNodeIP, "exit-node", "", "Tailscale IP of the exit node for internet traffic")
 		upf.BoolVar(&upArgs.shieldsUp, "shields-up", false, "don't allow incoming connections")
 		upf.BoolVar(&upArgs.forceReauth, "force-reauth", false, "force reauthentication")
 		upf.StringVar(&upArgs.advertiseTags, "advertise-tags", "", "ACL tags to request (comma-separated, e.g. eng,montreal,ssh)")
@@ -52,6 +54,7 @@ specify any flags, options are reset to their default.
 		upf.StringVar(&upArgs.hostname, "hostname", "", "hostname to use instead of the one provided by the OS")
 		if runtime.GOOS == "linux" || isBSD(runtime.GOOS) || version.OS() == "macOS" {
 			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)")
+			upf.BoolVar(&upArgs.advertiseDefaultRoute, "advertise-exit-node", false, "offer to be an exit node for internet traffic for the tailnet")
 		}
 		if runtime.GOOS == "linux" {
 			upf.BoolVar(&upArgs.snat, "snat-subnet-routes", true, "source NAT traffic to local routes advertised with --advertise-routes")
@@ -70,18 +73,20 @@ func defaultNetfilterMode() string {
 }
 
 var upArgs struct {
-	server          string
-	acceptRoutes    bool
-	acceptDNS       bool
-	singleRoutes    bool
-	shieldsUp       bool
-	forceReauth     bool
-	advertiseRoutes string
-	advertiseTags   string
-	snat            bool
-	netfilterMode   string
-	authKey         string
-	hostname        string
+	server                string
+	acceptRoutes          bool
+	acceptDNS             bool
+	singleRoutes          bool
+	exitNodeIP            string
+	shieldsUp             bool
+	forceReauth           bool
+	advertiseRoutes       string
+	advertiseDefaultRoute bool
+	advertiseTags         string
+	snat                  bool
+	netfilterMode         string
+	authKey               string
+	hostname              string
 }
 
 func isBSD(s string) bool {
@@ -120,6 +125,11 @@ func checkIPForwarding() {
 	}
 }
 
+var (
+	ipv4default = netaddr.MustParseIPPrefix("0.0.0.0/0")
+	ipv6default = netaddr.MustParseIPPrefix("::/0")
+)
+
 func runUp(ctx context.Context, args []string) error {
 	if len(args) > 0 {
 		log.Fatalf("too many non-flag arguments: %q", args)
@@ -133,12 +143,16 @@ func runUp(ctx context.Context, args []string) error {
 		if upArgs.acceptRoutes {
 			return errors.New("--accept-routes is " + notSupported)
 		}
+		if upArgs.exitNodeIP != "" {
+			return errors.New("--exit-node is " + notSupported)
+		}
 		if upArgs.netfilterMode != "off" {
 			return errors.New("--netfilter-mode values besides \"off\" " + notSupported)
 		}
 	}
 
-	var routes []netaddr.IPPrefix
+	routeMap := map[netaddr.IPPrefix]bool{}
+	var default4, default6 bool
 	if upArgs.advertiseRoutes != "" {
 		advroutes := strings.Split(upArgs.advertiseRoutes, ",")
 		for _, s := range advroutes {
@@ -149,10 +163,45 @@ func runUp(ctx context.Context, args []string) error {
 			if ipp != ipp.Masked() {
 				fatalf("%s has non-address bits set; expected %s", ipp, ipp.Masked())
 			}
-			routes = append(routes, ipp)
+			if ipp == ipv4default {
+				default4 = true
+			} else if ipp == ipv6default {
+				default6 = true
+			}
+			routeMap[ipp] = true
 		}
+		if default4 && !default6 {
+			fatalf("%s advertised without its IPv6 counterpart, please also advertise %s", ipv4default, ipv6default)
+		} else if default6 && !default4 {
+			fatalf("%s advertised without its IPv6 counterpart, please also advertise %s", ipv6default, ipv4default)
+		}
+	}
+	if upArgs.advertiseDefaultRoute {
+		routeMap[netaddr.MustParseIPPrefix("0.0.0.0/0")] = true
+		routeMap[netaddr.MustParseIPPrefix("::/0")] = true
+	}
+	if len(routeMap) > 0 {
 		checkIPForwarding()
 	}
+	routes := make([]netaddr.IPPrefix, 0, len(routeMap))
+	for r := range routeMap {
+		routes = append(routes, r)
+	}
+	sort.Slice(routes, func(i, j int) bool {
+		if routes[i].Bits != routes[j].Bits {
+			return routes[i].Bits < routes[j].Bits
+		}
+		return routes[i].IP.Less(routes[j].IP)
+	})
+
+	var exitNodeIP netaddr.IP
+	if upArgs.exitNodeIP != "" {
+		var err error
+		exitNodeIP, err = netaddr.ParseIP(upArgs.exitNodeIP)
+		if err != nil {
+			fatalf("invalid IP address %q for --exit-node: %v", upArgs.exitNodeIP, err)
+		}
+	}
 
 	var tags []string
 	if upArgs.advertiseTags != "" {
@@ -169,11 +218,11 @@ func runUp(ctx context.Context, args []string) error {
 		fatalf("hostname too long: %d bytes (max 256)", len(upArgs.hostname))
 	}
 
-	// TODO(apenwarr): fix different semantics between prefs and uflags
 	prefs := ipn.NewPrefs()
 	prefs.ControlURL = upArgs.server
 	prefs.WantRunning = true
 	prefs.RouteAll = upArgs.acceptRoutes
+	prefs.ExitNodeIP = exitNodeIP
 	prefs.CorpDNS = upArgs.acceptDNS
 	prefs.AllowSingleHosts = upArgs.singleRoutes
 	prefs.ShieldsUp = upArgs.shieldsUp
@@ -186,12 +235,12 @@ func runUp(ctx context.Context, args []string) error {
 	if runtime.GOOS == "linux" {
 		switch upArgs.netfilterMode {
 		case "on":
-			prefs.NetfilterMode = router.NetfilterOn
+			prefs.NetfilterMode = preftype.NetfilterOn
 		case "nodivert":
-			prefs.NetfilterMode = router.NetfilterNoDivert
+			prefs.NetfilterMode = preftype.NetfilterNoDivert
 			warnf("netfilter=nodivert; add iptables calls to ts-* chains manually.")
 		case "off":
-			prefs.NetfilterMode = router.NetfilterOff
+			prefs.NetfilterMode = preftype.NetfilterOff
 			warnf("netfilter=off; configure iptables yourself.")
 		default:
 			fatalf("invalid value --netfilter-mode: %q", upArgs.netfilterMode)
@@ -212,7 +261,16 @@ func runUp(ctx context.Context, args []string) error {
 		AuthKey:  upArgs.authKey,
 		Notify: func(n ipn.Notify) {
 			if n.ErrMessage != nil {
-				fatalf("backend error: %v\n", *n.ErrMessage)
+				msg := *n.ErrMessage
+				if msg == ipn.ErrMsgPermissionDenied {
+					switch runtime.GOOS {
+					case "windows":
+						msg += " (Tailscale service in use by other user?)"
+					default:
+						msg += " (try 'sudo tailscale up [...]')"
+					}
+				}
+				fatalf("backend error: %v\n", msg)
 			}
 			if s := n.State; s != nil {
 				switch *s {

cmd/tailscale/depaware.txt

@@ -2,124 +2,84 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
 
    W 💣 github.com/alexbrainman/sspi                                 from github.com/alexbrainman/sspi/negotiate
    W 💣 github.com/alexbrainman/sspi/negotiate                       from tailscale.com/net/tshttpproxy
-        github.com/apenwarr/fixconsole                               from tailscale.com/cmd/tailscale
-   W 💣 github.com/apenwarr/w32                                      from github.com/apenwarr/fixconsole
-   L    github.com/coreos/go-iptables/iptables                       from tailscale.com/wgengine/router
-  LW    github.com/go-multierror/multierror                          from tailscale.com/wgengine/router
-   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/wgengine/router/dns
-   L 💣 github.com/jsimonetti/rtnetlink                              from tailscale.com/wgengine/monitor
-   L    github.com/jsimonetti/rtnetlink/internal/unix                from github.com/jsimonetti/rtnetlink
-   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
         github.com/peterbourgon/ff/v2                                from github.com/peterbourgon/ff/v2/ffcli
         github.com/peterbourgon/ff/v2/ffcli                          from tailscale.com/cmd/tailscale/cli
-     💣 github.com/tailscale/wireguard-go/conn                       from github.com/tailscale/wireguard-go/device+
-     💣 github.com/tailscale/wireguard-go/device                     from tailscale.com/wgengine+
-        github.com/tailscale/wireguard-go/device/tokenbucket         from github.com/tailscale/wireguard-go/device
-     💣 github.com/tailscale/wireguard-go/ipc                        from github.com/tailscale/wireguard-go/device
-   W 💣 github.com/tailscale/wireguard-go/ipc/winpipe                from github.com/tailscale/wireguard-go/ipc
-        github.com/tailscale/wireguard-go/ratelimiter                from github.com/tailscale/wireguard-go/device
-        github.com/tailscale/wireguard-go/replay                     from github.com/tailscale/wireguard-go/device
-        github.com/tailscale/wireguard-go/rwcancel                   from github.com/tailscale/wireguard-go/device+
-        github.com/tailscale/wireguard-go/tai64n                     from github.com/tailscale/wireguard-go/device+
-     💣 github.com/tailscale/wireguard-go/tun                        from github.com/tailscale/wireguard-go/device+
-   W 💣 github.com/tailscale/wireguard-go/tun/wintun                 from github.com/tailscale/wireguard-go/tun+
-        github.com/tailscale/wireguard-go/wgcfg                      from github.com/tailscale/wireguard-go/device+
         github.com/tcnksm/go-httpstat                                from tailscale.com/net/netcheck
         github.com/toqueteos/webbrowser                              from tailscale.com/cmd/tailscale/cli
      💣 go4.org/intern                                               from inet.af/netaddr
-     💣 go4.org/mem                                                  from tailscale.com/control/controlclient+
+     💣 go4.org/mem                                                  from tailscale.com/derp+
         go4.org/unsafe/assume-no-moving-gc                           from go4.org/intern
    W 💣 golang.zx2c4.com/wireguard/windows/tunnel/winipcfg           from tailscale.com/net/interfaces+
         inet.af/netaddr                                              from tailscale.com/cmd/tailscale/cli+
         rsc.io/goversion/version                                     from tailscale.com/version
-        tailscale.com/atomicfile                                     from tailscale.com/ipn+
+        tailscale.com/atomicfile                                     from tailscale.com/ipn
         tailscale.com/cmd/tailscale/cli                              from tailscale.com/cmd/tailscale
-        tailscale.com/control/controlclient                          from tailscale.com/ipn+
-        tailscale.com/derp                                           from tailscale.com/derp/derphttp+
-        tailscale.com/derp/derphttp                                  from tailscale.com/cmd/tailscale/cli+
+        tailscale.com/derp                                           from tailscale.com/derp/derphttp
+        tailscale.com/derp/derphttp                                  from tailscale.com/net/netcheck
         tailscale.com/derp/derpmap                                   from tailscale.com/cmd/tailscale/cli
-        tailscale.com/disco                                          from tailscale.com/derp+
-        tailscale.com/internal/deepprint                             from tailscale.com/ipn+
+        tailscale.com/disco                                          from tailscale.com/derp
         tailscale.com/ipn                                            from tailscale.com/cmd/tailscale/cli
         tailscale.com/ipn/ipnstate                                   from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/ipn/policy                                     from tailscale.com/ipn
-        tailscale.com/log/logheap                                    from tailscale.com/control/controlclient
-        tailscale.com/logtail/backoff                                from tailscale.com/control/controlclient+
         tailscale.com/metrics                                        from tailscale.com/derp
-        tailscale.com/net/dnscache                                   from tailscale.com/control/controlclient+
+        tailscale.com/net/dnscache                                   from tailscale.com/derp/derphttp
         tailscale.com/net/flowtrack                                  from tailscale.com/wgengine/filter+
      💣 tailscale.com/net/interfaces                                 from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/net/netcheck                                   from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/net/netns                                      from tailscale.com/control/controlclient+
-        tailscale.com/net/packet                                     from tailscale.com/wgengine+
-        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+
-     💣 tailscale.com/net/tshttpproxy                                from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/paths                                          from tailscale.com/cmd/tailscale/cli
-        tailscale.com/portlist                                       from tailscale.com/ipn
+        tailscale.com/net/netcheck                                   from tailscale.com/cmd/tailscale/cli
+        tailscale.com/net/netns                                      from tailscale.com/derp/derphttp+
+        tailscale.com/net/packet                                     from tailscale.com/wgengine/filter
+        tailscale.com/net/portmapper                                 from tailscale.com/net/netcheck+
+        tailscale.com/net/stun                                       from tailscale.com/net/netcheck
+        tailscale.com/net/tlsdial                                    from tailscale.com/derp/derphttp
+        tailscale.com/net/tsaddr                                     from tailscale.com/net/interfaces
+     💣 tailscale.com/net/tshttpproxy                                from tailscale.com/derp/derphttp+
+        tailscale.com/paths                                          from tailscale.com/cmd/tailscale/cli+
         tailscale.com/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/types/empty                                    from tailscale.com/control/controlclient+
-        tailscale.com/types/key                                      from tailscale.com/cmd/tailscale/cli+
+        tailscale.com/types/empty                                    from tailscale.com/ipn
+        tailscale.com/types/key                                      from tailscale.com/derp+
         tailscale.com/types/logger                                   from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/types/nettype                                  from tailscale.com/wgengine/magicsock
-        tailscale.com/types/opt                                      from tailscale.com/control/controlclient+
+        tailscale.com/types/netmap                                   from tailscale.com/ipn
+        tailscale.com/types/opt                                      from tailscale.com/net/netcheck+
+        tailscale.com/types/persist                                  from tailscale.com/ipn
+        tailscale.com/types/preftype                                 from tailscale.com/cmd/tailscale/cli+
         tailscale.com/types/strbuilder                               from tailscale.com/net/packet
-        tailscale.com/types/structs                                  from tailscale.com/control/controlclient+
-        tailscale.com/types/wgkey                                    from tailscale.com/control/controlclient+
+        tailscale.com/types/structs                                  from tailscale.com/ipn+
+        tailscale.com/types/wgkey                                    from tailscale.com/types/netmap+
         tailscale.com/util/dnsname                                   from tailscale.com/cmd/tailscale/cli+
-  LW    tailscale.com/util/endian                                    from tailscale.com/net/netns+
-        tailscale.com/util/lineread                                  from tailscale.com/control/controlclient+
-        tailscale.com/util/systemd                                   from tailscale.com/control/controlclient+
+   W    tailscale.com/util/endian                                    from tailscale.com/net/netns
+        tailscale.com/util/lineread                                  from tailscale.com/net/interfaces
         tailscale.com/version                                        from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/version/distro                                 from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/wgengine                                       from tailscale.com/ipn
-        tailscale.com/wgengine/filter                                from tailscale.com/control/controlclient+
-        tailscale.com/wgengine/magicsock                             from tailscale.com/wgengine
-     💣 tailscale.com/wgengine/monitor                               from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/wgengine/router                                from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/wgengine/router/dns                            from tailscale.com/ipn+
-        tailscale.com/wgengine/tsdns                                 from tailscale.com/ipn+
-        tailscale.com/wgengine/tstun                                 from tailscale.com/wgengine
-   W 💣 tailscale.com/wgengine/winnet                                from tailscale.com/wgengine/router
+        tailscale.com/version/distro                                 from tailscale.com/cmd/tailscale/cli
+        tailscale.com/wgengine/filter                                from tailscale.com/types/netmap
         golang.org/x/crypto/blake2b                                  from golang.org/x/crypto/nacl/box
-        golang.org/x/crypto/blake2s                                  from github.com/tailscale/wireguard-go/device+
         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+
         golang.org/x/crypto/hkdf                                     from crypto/tls
-        golang.org/x/crypto/nacl/box                                 from tailscale.com/control/controlclient+
+        golang.org/x/crypto/nacl/box                                 from tailscale.com/derp
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
-        golang.org/x/crypto/poly1305                                 from github.com/tailscale/wireguard-go/device+
+        golang.org/x/crypto/poly1305                                 from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
-        golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
         golang.org/x/net/context/ctxhttp                             from golang.org/x/oauth2/internal
-        golang.org/x/net/dns/dnsmessage                              from net+
+        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
         golang.org/x/net/http2/hpack                                 from net/http
         golang.org/x/net/idna                                        from golang.org/x/net/http/httpguts+
-        golang.org/x/net/ipv4                                        from github.com/tailscale/wireguard-go/device
-        golang.org/x/net/ipv6                                        from github.com/tailscale/wireguard-go/device+
         golang.org/x/net/proxy                                       from tailscale.com/net/netns
-   D    golang.org/x/net/route                                       from net
-        golang.org/x/oauth2                                          from tailscale.com/control/controlclient+
+   D    golang.org/x/net/route                                       from net+
+        golang.org/x/oauth2                                          from tailscale.com/ipn+
         golang.org/x/oauth2/internal                                 from golang.org/x/oauth2
         golang.org/x/sync/errgroup                                   from tailscale.com/derp
         golang.org/x/sync/singleflight                               from tailscale.com/net/dnscache
         golang.org/x/sys/cpu                                         from golang.org/x/crypto/blake2b+
-  LD    golang.org/x/sys/unix                                        from github.com/jsimonetti/rtnetlink/internal/unix+
-   W    golang.org/x/sys/windows                                     from github.com/apenwarr/fixconsole+
-   W    golang.org/x/sys/windows/registry                            from golang.zx2c4.com/wireguard/windows/tunnel/winipcfg+
+  LD    golang.org/x/sys/unix                                        from tailscale.com/net/netns+
+   W    golang.org/x/sys/windows                                     from golang.org/x/sys/windows/registry+
+   W    golang.org/x/sys/windows/registry                            from golang.zx2c4.com/wireguard/windows/tunnel/winipcfg
         golang.org/x/text/secure/bidirule                            from golang.org/x/net/idna
         golang.org/x/text/transform                                  from golang.org/x/text/secure/bidirule+
         golang.org/x/text/unicode/bidi                               from golang.org/x/net/idna+
@@ -128,7 +88,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         bufio                                                        from compress/flate+
         bytes                                                        from bufio+
         compress/flate                                               from compress/gzip+
-        compress/gzip                                                from net/http+
+        compress/gzip                                                from net/http
         compress/zlib                                                from debug/elf+
         container/list                                               from crypto/tls+
         context                                                      from crypto/tls+
@@ -156,7 +116,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         debug/elf                                                    from rsc.io/goversion/version
         debug/macho                                                  from rsc.io/goversion/version
         debug/pe                                                     from rsc.io/goversion/version
-        encoding                                                     from encoding/json+
+        encoding                                                     from encoding/json
         encoding/asn1                                                from crypto/x509+
         encoding/base64                                              from encoding/json+
         encoding/binary                                              from compress/gzip+
@@ -170,16 +130,16 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         hash                                                         from compress/zlib+
         hash/adler32                                                 from compress/zlib
         hash/crc32                                                   from compress/gzip+
-        hash/fnv                                                     from tailscale.com/wgengine/magicsock
         hash/maphash                                                 from go4.org/mem
         html                                                         from tailscale.com/ipn/ipnstate
         io                                                           from bufio+
-        io/ioutil                                                    from crypto/tls+
+        io/fs                                                        from crypto/rand+
+        io/ioutil                                                    from golang.org/x/oauth2/internal+
         log                                                          from expvar+
         math                                                         from compress/flate+
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+
-        math/rand                                                    from github.com/mdlayher/netlink+
+        math/rand                                                    from math/big+
         mime                                                         from golang.org/x/oauth2/internal+
         mime/multipart                                               from net/http
         mime/quotedprintable                                         from mime/multipart
@@ -190,23 +150,21 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         net/textproto                                                from golang.org/x/net/http/httpguts+
         net/url                                                      from crypto/x509+
         os                                                           from crypto/rand+
-        os/exec                                                      from github.com/coreos/go-iptables/iptables+
+        os/exec                                                      from github.com/toqueteos/webbrowser+
         os/signal                                                    from tailscale.com/cmd/tailscale/cli
-   L    os/user                                                      from github.com/godbus/dbus/v5
         path                                                         from debug/dwarf+
         path/filepath                                                from crypto/x509+
         reflect                                                      from crypto/x509+
-        regexp                                                       from github.com/coreos/go-iptables/iptables+
+        regexp                                                       from rsc.io/goversion/version
         regexp/syntax                                                from regexp
         runtime/debug                                                from golang.org/x/sync/singleflight
-        runtime/pprof                                                from tailscale.com/log/logheap+
         sort                                                         from compress/flate+
         strconv                                                      from compress/flate+
         strings                                                      from bufio+
         sync                                                         from compress/flate+
         sync/atomic                                                  from context+
         syscall                                                      from crypto/rand+
-        text/tabwriter                                               from github.com/peterbourgon/ff/v2/ffcli+
+        text/tabwriter                                               from github.com/peterbourgon/ff/v2/ffcli
         time                                                         from compress/gzip+
         unicode                                                      from bytes+
         unicode/utf16                                                from encoding/asn1+

cmd/tailscale/tailscale.go

@@ -8,19 +8,12 @@ package main // import "tailscale.com/cmd/tailscale"
 
 import (
 	"fmt"
-	"log"
 	"os"
 
-	"github.com/apenwarr/fixconsole"
 	"tailscale.com/cmd/tailscale/cli"
 )
 
 func main() {
-	err := fixconsole.FixConsoleIfNeeded()
-	if err != nil {
-		log.Printf("fixConsoleOutput: %v\n", err)
-	}
-
 	if err := cli.Run(os.Args[1:]); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)

cmd/tailscaled/debug.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package cli
+package main
 
 import (
 	"context"
@@ -18,7 +18,6 @@ import (
 	"os"
 	"time"
 
-	"github.com/peterbourgon/ff/v2/ffcli"
 	"tailscale.com/derp/derphttp"
 	"tailscale.com/derp/derpmap"
 	"tailscale.com/net/interfaces"
@@ -28,28 +27,26 @@ import (
 	"tailscale.com/wgengine/monitor"
 )
 
-var debugCmd = &ffcli.Command{
-	Name: "debug",
-	Exec: runDebug,
-	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("debug", flag.ExitOnError)
-		fs.BoolVar(&debugArgs.monitor, "monitor", false, "If true, run link monitor forever. Precludes all other options.")
-		fs.StringVar(&debugArgs.getURL, "get-url", "", "If non-empty, fetch provided URL.")
-		fs.StringVar(&debugArgs.derpCheck, "derp", "", "if non-empty, test a DERP ping via named region code")
-		return fs
-	})(),
-}
-
 var debugArgs struct {
 	monitor   bool
 	getURL    string
 	derpCheck string
 }
 
-func runDebug(ctx context.Context, args []string) error {
-	if len(args) > 0 {
-		return errors.New("unknown arguments")
+var debugModeFunc = debugMode // so it can be addressable
+
+func debugMode(args []string) error {
+	fs := flag.NewFlagSet("debug", flag.ExitOnError)
+	fs.BoolVar(&debugArgs.monitor, "monitor", false, "If true, run link monitor forever. Precludes all other options.")
+	fs.StringVar(&debugArgs.getURL, "get-url", "", "If non-empty, fetch provided URL.")
+	fs.StringVar(&debugArgs.derpCheck, "derp", "", "if non-empty, test a DERP ping via named region code")
+	if err := fs.Parse(args); err != nil {
+		return err
 	}
+	if len(fs.Args()) > 0 {
+		return errors.New("unknown non-flag debug subcommand arguments")
+	}
+	ctx := context.Background()
 	if debugArgs.derpCheck != "" {
 		return checkDerp(ctx, debugArgs.derpCheck)
 	}
@@ -63,24 +60,24 @@ func runDebug(ctx context.Context, args []string) error {
 }
 
 func runMonitor(ctx context.Context) error {
-	dump := func() {
-		st, err := interfaces.GetState()
-		if err != nil {
-			log.Printf("error getting state: %v", err)
-			return
-		}
+	dump := func(st *interfaces.State) {
 		j, _ := json.MarshalIndent(st, "", "    ")
 		os.Stderr.Write(j)
 	}
-	mon, err := monitor.New(log.Printf, func() {
-		log.Printf("Link monitor fired. State:")
-		dump()
-	})
+	mon, err := monitor.New(log.Printf)
 	if err != nil {
 		return err
 	}
+	mon.RegisterChangeCallback(func(changed bool, st *interfaces.State) {
+		if changed {
+			log.Printf("Link monitor fired; no change")
+			return
+		}
+		log.Printf("Link monitor fired. New state:")
+		dump(st)
+	})
 	log.Printf("Starting link change monitor; initial state:")
-	dump()
+	dump(mon.InterfaceState())
 	mon.Start()
 	log.Printf("Started link change monitor; waiting...")
 	select {}

cmd/tailscaled/depaware.txt

@@ -2,14 +2,13 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
 
    W 💣 github.com/alexbrainman/sspi                                 from github.com/alexbrainman/sspi/negotiate
    W 💣 github.com/alexbrainman/sspi/negotiate                       from tailscale.com/net/tshttpproxy
-        github.com/apenwarr/fixconsole                               from tailscale.com/cmd/tailscaled
-   W 💣 github.com/apenwarr/w32                                      from github.com/apenwarr/fixconsole
    L    github.com/coreos/go-iptables/iptables                       from tailscale.com/wgengine/router
   LW    github.com/go-multierror/multierror                          from tailscale.com/wgengine/router
    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/wgengine/router/dns
         github.com/google/btree                                      from gvisor.dev/gvisor/pkg/tcpip/header+
+   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/internal/unix                from github.com/jsimonetti/rtnetlink
         github.com/klauspost/compress/fse                            from github.com/klauspost/compress/huff0
@@ -22,7 +21,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    L    github.com/mdlayher/sdnotify                                 from tailscale.com/util/systemd
      💣 github.com/tailscale/wireguard-go/conn                       from github.com/tailscale/wireguard-go/device+
      💣 github.com/tailscale/wireguard-go/device                     from tailscale.com/wgengine+
-        github.com/tailscale/wireguard-go/device/tokenbucket         from github.com/tailscale/wireguard-go/device
      💣 github.com/tailscale/wireguard-go/ipc                        from github.com/tailscale/wireguard-go/device
    W 💣 github.com/tailscale/wireguard-go/ipc/winpipe                from github.com/tailscale/wireguard-go/ipc
         github.com/tailscale/wireguard-go/ratelimiter                from github.com/tailscale/wireguard-go/device
@@ -31,7 +29,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         github.com/tailscale/wireguard-go/tai64n                     from github.com/tailscale/wireguard-go/device+
      💣 github.com/tailscale/wireguard-go/tun                        from github.com/tailscale/wireguard-go/device+
    W 💣 github.com/tailscale/wireguard-go/tun/wintun                 from github.com/tailscale/wireguard-go/tun+
-        github.com/tailscale/wireguard-go/wgcfg                      from github.com/tailscale/wireguard-go/device+
         github.com/tcnksm/go-httpstat                                from tailscale.com/net/netcheck
      💣 go4.org/intern                                               from inet.af/netaddr
      💣 go4.org/mem                                                  from tailscale.com/control/controlclient+
@@ -52,10 +49,11 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         gvisor.dev/gvisor/pkg/tcpip/header                           from gvisor.dev/gvisor/pkg/tcpip/link/channel+
         gvisor.dev/gvisor/pkg/tcpip/header/parse                     from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
         gvisor.dev/gvisor/pkg/tcpip/link/channel                     from tailscale.com/wgengine/netstack
-        gvisor.dev/gvisor/pkg/tcpip/network/fragmentation            from gvisor.dev/gvisor/pkg/tcpip/network/ipv4
-        gvisor.dev/gvisor/pkg/tcpip/network/hash                     from gvisor.dev/gvisor/pkg/tcpip/network/ipv4
-        gvisor.dev/gvisor/pkg/tcpip/network/ip                       from gvisor.dev/gvisor/pkg/tcpip/network/ipv4
+        gvisor.dev/gvisor/pkg/tcpip/network/fragmentation            from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
+        gvisor.dev/gvisor/pkg/tcpip/network/hash                     from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
+        gvisor.dev/gvisor/pkg/tcpip/network/ip                       from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
         gvisor.dev/gvisor/pkg/tcpip/network/ipv4                     from tailscale.com/wgengine/netstack
+        gvisor.dev/gvisor/pkg/tcpip/network/ipv6                     from tailscale.com/wgengine/netstack
         gvisor.dev/gvisor/pkg/tcpip/ports                            from gvisor.dev/gvisor/pkg/tcpip/stack+
         gvisor.dev/gvisor/pkg/tcpip/seqnum                           from gvisor.dev/gvisor/pkg/tcpip/header+
         gvisor.dev/gvisor/pkg/tcpip/stack                            from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
@@ -67,17 +65,22 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         gvisor.dev/gvisor/pkg/tcpip/transport/udp                    from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
         gvisor.dev/gvisor/pkg/waiter                                 from gvisor.dev/gvisor/pkg/tcpip+
         inet.af/netaddr                                              from tailscale.com/control/controlclient+
+        inet.af/peercred                                             from tailscale.com/ipn/ipnserver
         rsc.io/goversion/version                                     from tailscale.com/version
         tailscale.com/atomicfile                                     from tailscale.com/ipn+
-        tailscale.com/control/controlclient                          from tailscale.com/ipn+
+        tailscale.com/control/controlclient                          from tailscale.com/ipn/ipnlocal+
         tailscale.com/derp                                           from tailscale.com/derp/derphttp+
         tailscale.com/derp/derphttp                                  from tailscale.com/net/netcheck+
+        tailscale.com/derp/derpmap                                   from tailscale.com/cmd/tailscaled+
         tailscale.com/disco                                          from tailscale.com/derp+
-        tailscale.com/internal/deepprint                             from tailscale.com/ipn+
-        tailscale.com/ipn                                            from tailscale.com/ipn/ipnserver
+        tailscale.com/health                                         from tailscale.com/control/controlclient+
+        tailscale.com/internal/deepprint                             from tailscale.com/ipn/ipnlocal+
+        tailscale.com/ipn                                            from tailscale.com/ipn/ipnserver+
+        tailscale.com/ipn/ipnlocal                                   from tailscale.com/ipn/ipnserver+
         tailscale.com/ipn/ipnserver                                  from tailscale.com/cmd/tailscaled
         tailscale.com/ipn/ipnstate                                   from tailscale.com/ipn+
-        tailscale.com/ipn/policy                                     from tailscale.com/ipn
+        tailscale.com/ipn/localapi                                   from tailscale.com/ipn/ipnserver
+        tailscale.com/ipn/policy                                     from tailscale.com/ipn/ipnlocal
         tailscale.com/log/filelogger                                 from tailscale.com/ipn/ipnserver
         tailscale.com/log/logheap                                    from tailscale.com/control/controlclient
         tailscale.com/logpolicy                                      from tailscale.com/cmd/tailscaled
@@ -86,33 +89,42 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/logtail/filch                                  from tailscale.com/logpolicy
         tailscale.com/metrics                                        from tailscale.com/derp
         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/wgengine/filter+
-     💣 tailscale.com/net/interfaces                                 from tailscale.com/ipn+
+     💣 tailscale.com/net/interfaces                                 from tailscale.com/cmd/tailscaled+
         tailscale.com/net/netcheck                                   from tailscale.com/wgengine/magicsock
         tailscale.com/net/netns                                      from tailscale.com/control/controlclient+
      💣 tailscale.com/net/netstat                                    from tailscale.com/ipn/ipnserver
         tailscale.com/net/packet                                     from tailscale.com/wgengine+
+        tailscale.com/net/portmapper                                 from tailscale.com/net/netcheck+
+        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+
+        tailscale.com/net/tsaddr                                     from tailscale.com/ipn/ipnlocal+
      💣 tailscale.com/net/tshttpproxy                                from tailscale.com/control/controlclient+
         tailscale.com/paths                                          from tailscale.com/cmd/tailscaled+
-        tailscale.com/portlist                                       from tailscale.com/ipn
+        tailscale.com/portlist                                       from tailscale.com/ipn/ipnlocal
         tailscale.com/safesocket                                     from tailscale.com/ipn/ipnserver
         tailscale.com/smallzstd                                      from tailscale.com/ipn/ipnserver+
-     💣 tailscale.com/syncs                                          from tailscale.com/net/interfaces+
+        tailscale.com/syncs                                          from tailscale.com/net/interfaces+
         tailscale.com/tailcfg                                        from tailscale.com/control/controlclient+
+   W 💣 tailscale.com/tempfork/wireguard-windows/firewall            from tailscale.com/cmd/tailscaled
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
+        tailscale.com/tstime                                         from tailscale.com/wgengine/magicsock
         tailscale.com/types/empty                                    from tailscale.com/control/controlclient+
         tailscale.com/types/flagtype                                 from tailscale.com/cmd/tailscaled
         tailscale.com/types/key                                      from tailscale.com/derp+
         tailscale.com/types/logger                                   from tailscale.com/cmd/tailscaled+
+        tailscale.com/types/netmap                                   from tailscale.com/control/controlclient+
         tailscale.com/types/nettype                                  from tailscale.com/wgengine/magicsock
         tailscale.com/types/opt                                      from tailscale.com/control/controlclient+
+        tailscale.com/types/pad32                                    from tailscale.com/wgengine/magicsock
+        tailscale.com/types/persist                                  from tailscale.com/control/controlclient+
+        tailscale.com/types/preftype                                 from tailscale.com/ipn+
         tailscale.com/types/strbuilder                               from tailscale.com/net/packet
         tailscale.com/types/structs                                  from tailscale.com/control/controlclient+
         tailscale.com/types/wgkey                                    from tailscale.com/control/controlclient+
-        tailscale.com/util/dnsname                                   from tailscale.com/control/controlclient+
+        tailscale.com/util/dnsname                                   from tailscale.com/wgengine/tsdns+
   LW    tailscale.com/util/endian                                    from tailscale.com/net/netns+
         tailscale.com/util/lineread                                  from tailscale.com/control/controlclient+
         tailscale.com/util/pidowner                                  from tailscale.com/ipn/ipnserver
@@ -123,12 +135,15 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/wgengine                                       from tailscale.com/cmd/tailscaled+
         tailscale.com/wgengine/filter                                from tailscale.com/control/controlclient+
         tailscale.com/wgengine/magicsock                             from tailscale.com/cmd/tailscaled+
-     💣 tailscale.com/wgengine/monitor                               from tailscale.com/wgengine
+     💣 tailscale.com/wgengine/monitor                               from tailscale.com/wgengine+
         tailscale.com/wgengine/netstack                              from tailscale.com/cmd/tailscaled
         tailscale.com/wgengine/router                                from tailscale.com/cmd/tailscaled+
-        tailscale.com/wgengine/router/dns                            from tailscale.com/ipn+
-        tailscale.com/wgengine/tsdns                                 from tailscale.com/ipn+
+        tailscale.com/wgengine/router/dns                            from tailscale.com/ipn/ipnlocal+
+        tailscale.com/wgengine/tsdns                                 from tailscale.com/ipn/ipnlocal+
         tailscale.com/wgengine/tstun                                 from tailscale.com/wgengine+
+        tailscale.com/wgengine/wgcfg                                 from tailscale.com/ipn/ipnlocal+
+        tailscale.com/wgengine/wgcfg/nmcfg                           from tailscale.com/ipn/ipnlocal
+        tailscale.com/wgengine/wglog                                 from tailscale.com/wgengine
    W 💣 tailscale.com/wgengine/winnet                                from tailscale.com/wgengine/router
         golang.org/x/crypto/blake2b                                  from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/blake2s                                  from github.com/tailscale/wireguard-go/device+
@@ -152,15 +167,16 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         golang.org/x/net/ipv4                                        from github.com/tailscale/wireguard-go/device
         golang.org/x/net/ipv6                                        from github.com/tailscale/wireguard-go/device+
         golang.org/x/net/proxy                                       from tailscale.com/net/netns
-   D    golang.org/x/net/route                                       from net
+   D    golang.org/x/net/route                                       from net+
         golang.org/x/oauth2                                          from tailscale.com/control/controlclient+
         golang.org/x/oauth2/internal                                 from golang.org/x/oauth2
         golang.org/x/sync/errgroup                                   from tailscale.com/derp
         golang.org/x/sync/singleflight                               from tailscale.com/net/dnscache
         golang.org/x/sys/cpu                                         from golang.org/x/crypto/blake2b+
   LD    golang.org/x/sys/unix                                        from github.com/jsimonetti/rtnetlink/internal/unix+
-   W    golang.org/x/sys/windows                                     from github.com/apenwarr/fixconsole+
+   W    golang.org/x/sys/windows                                     from github.com/tailscale/wireguard-go/conn+
    W    golang.org/x/sys/windows/registry                            from golang.zx2c4.com/wireguard/windows/tunnel/winipcfg+
+   W    golang.org/x/sys/windows/svc                                 from tailscale.com/cmd/tailscaled
         golang.org/x/term                                            from tailscale.com/logpolicy
         golang.org/x/text/secure/bidirule                            from golang.org/x/net/idna
         golang.org/x/text/transform                                  from golang.org/x/text/secure/bidirule+
@@ -213,12 +229,12 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         hash                                                         from compress/zlib+
         hash/adler32                                                 from compress/zlib
         hash/crc32                                                   from compress/gzip+
-        hash/fnv                                                     from tailscale.com/wgengine/magicsock
+        hash/fnv                                                     from tailscale.com/wgengine/magicsock+
         hash/maphash                                                 from go4.org/mem
-        html                                                         from html/template+
-        html/template                                                from net/http/pprof
+        html                                                         from net/http/pprof+
         io                                                           from bufio+
-        io/ioutil                                                    from crypto/tls+
+        io/fs                                                        from crypto/rand+
+        io/ioutil                                                    from github.com/godbus/dbus/v5+
         log                                                          from expvar+
         math                                                         from compress/flate+
         math/big                                                     from crypto/dsa+
@@ -253,8 +269,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         sync/atomic                                                  from context+
         syscall                                                      from crypto/rand+
         text/tabwriter                                               from runtime/pprof
-        text/template                                                from html/template
-        text/template/parse                                          from html/template+
         time                                                         from compress/gzip+
         unicode                                                      from bytes+
         unicode/utf16                                                from encoding/asn1+

cmd/tailscaled/install_darwin.go

@@ -0,0 +1,146 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+)
+
+func init() {
+	installSystemDaemon = installSystemDaemonDarwin
+	uninstallSystemDaemon = uninstallSystemDaemonDarwin
+}
+
+// darwinLaunchdPlist is the launchd.plist that's written to
+// /Library/LaunchDaemons/com.tailscale.tailscaled.plist or (in the
+// future) a user-specific location.
+//
+// See man launchd.plist.
+const darwinLaunchdPlist = `
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+
+  <key>Label</key>
+  <string>com.tailscale.tailscaled</string>
+
+  <key>ProgramArguments</key>
+  <array>
+    <string>/usr/local/bin/tailscaled</string>
+  </array>
+
+  <key>RunAtLoad</key>
+  <true/>
+
+</dict>
+</plist>
+`
+
+const sysPlist = "/Library/LaunchDaemons/com.tailscale.tailscaled.plist"
+const targetBin = "/usr/local/bin/tailscaled"
+const service = "com.tailscale.tailscaled"
+
+func uninstallSystemDaemonDarwin(args []string) (ret error) {
+	if len(args) > 0 {
+		return errors.New("uninstall subcommand takes no arguments")
+	}
+
+	plist, err := exec.Command("launchctl", "list", "com.tailscale.tailscaled").Output()
+	_ = plist // parse it? https://github.com/DHowett/go-plist if we need something.
+	running := err == nil
+
+	if running {
+		out, err := exec.Command("launchctl", "stop", "com.tailscale.tailscaled").CombinedOutput()
+		if err != nil {
+			fmt.Printf("launchctl stop com.tailscale.tailscaled: %v, %s\n", err, out)
+			ret = err
+		}
+		out, err = exec.Command("launchctl", "unload", sysPlist).CombinedOutput()
+		if err != nil {
+			fmt.Printf("launchctl unload %s: %v, %s\n", sysPlist, err, out)
+			if ret == nil {
+				ret = err
+			}
+		}
+	}
+
+	err = os.Remove(sysPlist)
+	if os.IsNotExist(err) {
+		err = nil
+		if ret == nil {
+			ret = err
+		}
+	}
+	return ret
+}
+
+func installSystemDaemonDarwin(args []string) (err error) {
+	if len(args) > 0 {
+		return errors.New("install subcommand takes no arguments")
+	}
+	defer func() {
+		if err != nil && os.Getuid() != 0 {
+			err = fmt.Errorf("%w; try running tailscaled with sudo", err)
+		}
+	}()
+
+	// Copy ourselves to /usr/local/bin/tailscaled.
+	if err := os.MkdirAll(filepath.Dir(targetBin), 0755); err != nil {
+		return err
+	}
+	exe, err := os.Executable()
+	if err != nil {
+		return fmt.Errorf("failed to find our own executable path: %w", err)
+	}
+	tmpBin := targetBin + ".tmp"
+	f, err := os.Create(tmpBin)
+	if err != nil {
+		return err
+	}
+	self, err := os.Open(exe)
+	if err != nil {
+		f.Close()
+		return err
+	}
+	_, err = io.Copy(f, self)
+	self.Close()
+	if err != nil {
+		f.Close()
+		return err
+	}
+	if err := f.Close(); err != nil {
+		return err
+	}
+	if err := os.Chmod(tmpBin, 0755); err != nil {
+		return err
+	}
+	if err := os.Rename(tmpBin, targetBin); err != nil {
+		return err
+	}
+
+	// Best effort:
+	uninstallSystemDaemonDarwin(nil)
+
+	if err := ioutil.WriteFile(sysPlist, []byte(darwinLaunchdPlist), 0700); err != nil {
+		return err
+	}
+
+	if out, err := exec.Command("launchctl", "load", sysPlist).CombinedOutput(); err != nil {
+		return fmt.Errorf("error running launchctl load %s: %v, %s", sysPlist, err, out)
+	}
+
+	if out, err := exec.Command("launchctl", "start", service).CombinedOutput(); err != nil {
+		return fmt.Errorf("error running launchctl start %s: %v, %s", service, err, out)
+	}
+
+	return nil
+}

cmd/tailscaled/tailscaled.go

@@ -14,6 +14,7 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"net"
 	"net/http"
 	"net/http/pprof"
 	"os"
@@ -21,20 +22,24 @@ import (
 	"runtime"
 	"runtime/debug"
 	"strconv"
+	"sync"
 	"syscall"
 	"time"
 
-	"github.com/apenwarr/fixconsole"
 	"tailscale.com/ipn/ipnserver"
 	"tailscale.com/logpolicy"
+	"tailscale.com/net/socks5"
 	"tailscale.com/paths"
 	"tailscale.com/types/flagtype"
 	"tailscale.com/types/logger"
+	"tailscale.com/types/netmap"
 	"tailscale.com/version"
 	"tailscale.com/wgengine"
 	"tailscale.com/wgengine/magicsock"
+	"tailscale.com/wgengine/monitor"
 	"tailscale.com/wgengine/netstack"
 	"tailscale.com/wgengine/router"
+	"tailscale.com/wgengine/tstun"
 )
 
 // globalStateKey is the ipn.StateKey that tailscaled loads on
@@ -53,19 +58,34 @@ func defaultTunName() string {
 		return "tun"
 	case "windows":
 		return "Tailscale"
+	case "darwin":
+		// "utun" is recognized by wireguard-go/tun/tun_darwin.go
+		// as a magic value that uses/creates any free number.
+		return "utun"
 	}
 	return "tailscale0"
 }
 
 var args struct {
 	cleanup    bool
-	fake       bool
 	debug      string
 	tunname    string
 	port       uint16
 	statepath  string
 	socketpath string
 	verbose    int
+	socksAddr  string // listen address for SOCKS5 server
+}
+
+var (
+	installSystemDaemon   func([]string) error // non-nil on some platforms
+	uninstallSystemDaemon func([]string) error // non-nil on some platforms
+)
+
+var subCommands = map[string]*func([]string) error{
+	"install-system-daemon":   &installSystemDaemon,
+	"uninstall-system-daemon": &uninstallSystemDaemon,
+	"debug":                   &debugModeFunc,
 }
 
 func main() {
@@ -80,17 +100,31 @@ func main() {
 	printVersion := false
 	flag.IntVar(&args.verbose, "verbose", 0, "log verbosity level; 0 is default, 1 or higher are increasingly verbose")
 	flag.BoolVar(&args.cleanup, "cleanup", false, "clean up system state and exit")
-	flag.BoolVar(&args.fake, "fake", false, "use userspace fake tunnel+routing instead of kernel TUN interface")
 	flag.StringVar(&args.debug, "debug", "", "listen address ([ip]:port) of optional debug server")
-	flag.StringVar(&args.tunname, "tun", defaultTunName(), "tunnel interface name")
+	flag.StringVar(&args.socksAddr, "socks5-server", "", `optional [ip]:port to run a SOCK5 server (e.g. "localhost:1080")`)
+	flag.StringVar(&args.tunname, "tun", defaultTunName(), `tunnel interface name; use "userspace-networking" (beta) to not use TUN`)
 	flag.Var(flagtype.PortValue(&args.port, magicsock.DefaultPort), "port", "UDP port to listen on for WireGuard and peer-to-peer traffic; 0 means automatically select")
 	flag.StringVar(&args.statepath, "state", paths.DefaultTailscaledStateFile(), "path of state file")
 	flag.StringVar(&args.socketpath, "socket", paths.DefaultTailscaledSocket(), "path of the service unix socket")
 	flag.BoolVar(&printVersion, "version", false, "print version information and exit")
 
-	err := fixconsole.FixConsoleIfNeeded()
-	if err != nil {
-		log.Fatalf("fixConsoleOutput: %v", err)
+	if len(os.Args) > 1 {
+		sub := os.Args[1]
+		if fp, ok := subCommands[sub]; ok {
+			if *fp == nil {
+				log.SetFlags(0)
+				log.Fatalf("%s not available on %v", sub, runtime.GOOS)
+			}
+			if err := (*fp)(os.Args[2:]); err != nil {
+				log.SetFlags(0)
+				log.Fatal(err)
+			}
+			return
+		}
+	}
+
+	if beWindowsSubprocess() {
+		return
 	}
 
 	flag.Parse()
@@ -103,11 +137,13 @@ func main() {
 		os.Exit(0)
 	}
 
-	if args.statepath == "" {
-		log.Fatalf("--state is required")
+	if runtime.GOOS == "darwin" && os.Getuid() != 0 {
+		log.SetFlags(0)
+		log.Fatalf("tailscaled requires root; use sudo tailscaled")
 	}
 
 	if args.socketpath == "" && runtime.GOOS != "windows" {
+		log.SetFlags(0)
 		log.Fatalf("--socket is required")
 	}
 
@@ -129,6 +165,16 @@ func run() error {
 		pol.Shutdown(ctx)
 	}()
 
+	if isWindowsService() {
+		// Run the IPN server from the Windows service manager.
+		log.Printf("Running service...")
+		if err := runWindowsService(pol); err != nil {
+			log.Printf("runservice: %v", err)
+		}
+		log.Printf("Service ended.")
+		return nil
+	}
+
 	var logf logger.Logf = log.Printf
 	if v, _ := strconv.ParseBool(os.Getenv("TS_DEBUG_MEMORY")); v {
 		logf = logger.RusagePrefixLog(logf)
@@ -140,26 +186,90 @@ func run() error {
 		return nil
 	}
 
+	if args.statepath == "" {
+		log.Fatalf("--state is required")
+	}
+
 	var debugMux *http.ServeMux
 	if args.debug != "" {
 		debugMux = newDebugMux()
 		go runDebugServer(debugMux, args.debug)
 	}
 
-	var e wgengine.Engine
-	if args.fake {
-		var impl wgengine.FakeImplFunc
-		if args.tunname == "userspace-networking" {
-			impl = netstack.Impl
-		}
-		e, err = wgengine.NewFakeUserspaceEngine(logf, 0, impl)
-	} else {
-		e, err = wgengine.NewUserspaceEngine(logf, args.tunname, args.port)
+	linkMon, err := monitor.New(logf)
+	if err != nil {
+		log.Fatalf("creating link monitor: %v", err)
 	}
+	pol.Logtail.SetLinkMonitor(linkMon)
+
+	var socksListener net.Listener
+	if args.socksAddr != "" {
+		var err error
+		socksListener, err = net.Listen("tcp", args.socksAddr)
+		if err != nil {
+			log.Fatalf("SOCKS5 listener: %v", err)
+		}
+	}
+
+	conf := wgengine.Config{
+		ListenPort:  args.port,
+		LinkMonitor: linkMon,
+	}
+	if args.tunname == "userspace-networking" {
+		conf.TUN = tstun.NewFakeTUN()
+		conf.RouterGen = router.NewFake
+	} else {
+		conf.TUNName = args.tunname
+	}
+
+	e, err := wgengine.NewUserspaceEngine(logf, conf)
 	if err != nil {
 		logf("wgengine.New: %v", err)
 		return err
 	}
+
+	var ns *netstack.Impl
+	if args.tunname == "userspace-networking" {
+		tunDev, magicConn := e.(wgengine.InternalsGetter).GetInternals()
+		ns, err = netstack.Create(logf, tunDev, e, magicConn)
+		if err != nil {
+			log.Fatalf("netstack.Create: %v", err)
+		}
+		if err := ns.Start(); err != nil {
+			log.Fatalf("failed to start netstack: %v", err)
+		}
+	}
+
+	if socksListener != nil {
+		srv := &socks5.Server{
+			Logf: logger.WithPrefix(logf, "socks5: "),
+		}
+		if args.tunname == "userspace-networking" {
+			srv.Dialer = func(ctx context.Context, network, addr string) (net.Conn, error) {
+				return ns.DialContextTCP(ctx, addr)
+			}
+		} else {
+			var mu sync.Mutex
+			var dns netstack.DNSMap
+			e.AddNetworkMapCallback(func(nm *netmap.NetworkMap) {
+				mu.Lock()
+				defer mu.Unlock()
+				dns = netstack.DNSMapFromNetworkMap(nm)
+			})
+			srv.Dialer = func(ctx context.Context, network, addr string) (net.Conn, error) {
+				ipp, err := dns.Resolve(ctx, addr)
+				if err != nil {
+					return nil, err
+				}
+				var d net.Dialer
+				return d.DialContext(ctx, network, ipp.String())
+			}
+		}
+		go func() {
+			log.Fatalf("SOCKS5 server exited: %v", srv.Serve(socksListener))
+		}()
+	}
+
 	e = wgengine.NewWatchdog(e)
 
 	ctx, cancel := context.WithCancel(context.Background())

cmd/tailscaled/tailscaled.service

@@ -20,22 +20,5 @@ CacheDirectory=tailscale
 CacheDirectoryMode=0750
 Type=notify
 
-DeviceAllow=/dev/net/tun
-DeviceAllow=/dev/null
-DeviceAllow=/dev/random
-DeviceAllow=/dev/urandom
-DevicePolicy=strict
-LockPersonality=true
-MemoryDenyWriteExecute=true
-PrivateTmp=true
-ProtectClock=true
-ProtectControlGroups=true
-ProtectHome=true
-ProtectKernelTunables=true
-ProtectSystem=strict
-ReadWritePaths=/etc/
-RestrictSUIDSGID=true
-SystemCallArchitectures=native
-
 [Install]
 WantedBy=multi-user.target

cmd/tailscaled/tailscaled_notwindows.go

@@ -0,0 +1,15 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !windows
+
+package main // import "tailscale.com/cmd/tailscaled"
+
+import "tailscale.com/logpolicy"
+
+func isWindowsService() bool { return false }
+
+func runWindowsService(pol *logpolicy.Policy) error { panic("unreachable") }
+
+func beWindowsSubprocess() bool { return false }

cmd/tailscaled/tailscaled_windows.go

@@ -0,0 +1,228 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main // import "tailscale.com/cmd/tailscaled"
+
+// TODO: check if administrator, like tswin does.
+//
+// TODO: try to load wintun.dll early at startup, before wireguard/tun
+//       does (which panics) and if we'd fail (e.g. due to access
+//       denied, even if administrator), use 'tasklist /m wintun.dll'
+//       to see if something else is currently using it and tell user.
+//
+// TODO: check if Tailscale service is already running, and fail early
+//       like tswin does.
+//
+// TODO: on failure, check if on a UNC drive and recommend copying it
+//       to C:\ to run it, like tswin does.
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"time"
+
+	"golang.org/x/sys/windows"
+	"golang.org/x/sys/windows/svc"
+	"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
+	"tailscale.com/ipn/ipnserver"
+	"tailscale.com/logpolicy"
+	"tailscale.com/tempfork/wireguard-windows/firewall"
+	"tailscale.com/types/logger"
+	"tailscale.com/version"
+	"tailscale.com/wgengine"
+)
+
+const serviceName = "Tailscale"
+
+func isWindowsService() bool {
+	v, err := svc.IsWindowsService()
+	if err != nil {
+		log.Fatalf("svc.IsWindowsService failed: %v", err)
+	}
+	return v
+}
+
+func runWindowsService(pol *logpolicy.Policy) error {
+	return svc.Run(serviceName, &ipnService{Policy: pol})
+}
+
+type ipnService struct {
+	Policy *logpolicy.Policy
+}
+
+// Called by Windows to execute the windows service.
+func (service *ipnService) Execute(args []string, r <-chan svc.ChangeRequest, changes chan<- svc.Status) (bool, uint32) {
+	changes <- svc.Status{State: svc.StartPending}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	doneCh := make(chan struct{})
+	go func() {
+		defer close(doneCh)
+		args := []string{"/subproc", service.Policy.PublicID.String()}
+		ipnserver.BabysitProc(ctx, args, log.Printf)
+	}()
+
+	changes <- svc.Status{State: svc.Running, Accepts: svc.AcceptStop}
+
+	for ctx.Err() == nil {
+		select {
+		case <-doneCh:
+		case cmd := <-r:
+			switch cmd.Cmd {
+			case svc.Stop:
+				cancel()
+			case svc.Interrogate:
+				changes <- cmd.CurrentStatus
+			}
+		}
+	}
+
+	changes <- svc.Status{State: svc.StopPending}
+	return false, windows.NO_ERROR
+}
+
+func beWindowsSubprocess() bool {
+	if beFirewallKillswitch() {
+		return true
+	}
+
+	if len(os.Args) != 3 || os.Args[1] != "/subproc" {
+		return false
+	}
+	logid := os.Args[2]
+
+	log.Printf("Program starting: v%v: %#v", version.Long, os.Args)
+	log.Printf("subproc mode: logid=%v", logid)
+
+	go func() {
+		b := make([]byte, 16)
+		for {
+			_, err := os.Stdin.Read(b)
+			if err != nil {
+				log.Fatalf("stdin err (parent process died): %v", err)
+			}
+		}
+	}()
+
+	err := startIPNServer(context.Background(), logid)
+	if err != nil {
+		log.Fatalf("ipnserver: %v", err)
+	}
+	return true
+}
+
+func beFirewallKillswitch() bool {
+	if len(os.Args) != 3 || os.Args[1] != "/firewall" {
+		return false
+	}
+
+	log.SetFlags(0)
+	log.Printf("killswitch subprocess starting, tailscale GUID is %s", os.Args[2])
+
+	go func() {
+		b := make([]byte, 16)
+		for {
+			_, err := os.Stdin.Read(b)
+			if err != nil {
+				log.Fatalf("parent process died or requested exit, exiting (%v)", err)
+			}
+		}
+	}()
+
+	guid, err := windows.GUIDFromString(os.Args[2])
+	if err != nil {
+		log.Fatalf("invalid GUID %q: %v", os.Args[2], err)
+	}
+
+	luid, err := winipcfg.LUIDFromGUID(&guid)
+	if err != nil {
+		log.Fatalf("no interface with GUID %q", guid)
+	}
+
+	noProtection := false
+	var dnsIPs []net.IP // unused in called code.
+	start := time.Now()
+	firewall.EnableFirewall(uint64(luid), noProtection, dnsIPs)
+	log.Printf("killswitch enabled, took %s", time.Since(start))
+
+	// Block until the monitor goroutine shuts us down.
+	select {}
+}
+
+func startIPNServer(ctx context.Context, logid string) error {
+	var logf logger.Logf = log.Printf
+	var eng wgengine.Engine
+	var err error
+
+	getEngine := func() (wgengine.Engine, error) {
+		eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
+			TUNName:    "Tailscale",
+			ListenPort: 41641,
+		})
+		if err != nil {
+			return nil, err
+		}
+		return wgengine.NewWatchdog(eng), nil
+	}
+
+	if msg := os.Getenv("TS_DEBUG_WIN_FAIL"); msg != "" {
+		err = fmt.Errorf("pretending to be a service failure: %v", msg)
+	} else {
+		// We have a bunch of bug reports of wgengine.NewUserspaceEngine returning a few different errors,
+		// all intermittently. A few times I (Brad) have also seen sporadic failures that simply
+		// restarting fixed. So try a few times.
+		for try := 1; try <= 5; try++ {
+			if try > 1 {
+				// Only sleep a bit. Don't do some massive backoff because
+				// the frontend GUI has a 30 second timeout on connecting to us,
+				// but even 5 seconds is too long for them to get any results.
+				// 5 tries * 1 second each seems fine.
+				time.Sleep(time.Second)
+			}
+			eng, err = getEngine()
+			if err != nil {
+				logf("wgengine.NewUserspaceEngine: (try %v) %v", try, err)
+				continue
+			}
+			if try > 1 {
+				logf("wgengine.NewUserspaceEngine: ended up working on try %v", try)
+			}
+			break
+		}
+	}
+	if err != nil {
+		// Log the error, but don't fatalf. We want to
+		// propagate the error message to the UI frontend. So
+		// we continue and tell the ipnserver to return that
+		// in a Notify message.
+		logf("wgengine.NewUserspaceEngine: %v", err)
+	}
+	opts := ipnserver.Options{
+		Port:               41112,
+		SurviveDisconnects: false,
+		StatePath:          args.statepath,
+	}
+	if err != nil {
+		// Return nicer errors to users, annotated with logids, which helps
+		// when they file bugs.
+		rawGetEngine := getEngine // raw == without verbose logid-containing error
+		getEngine = func() (wgengine.Engine, error) {
+			eng, err := rawGetEngine()
+			if err != nil {
+				return nil, fmt.Errorf("wgengine.NewUserspaceEngine: %v\n\nlogid: %v", err, logid)
+			}
+			return eng, nil
+		}
+	} else {
+		getEngine = ipnserver.FixedEngine(eng)
+	}
+	err = ipnserver.Run(ctx, logf, logid, getEngine, opts)
+	if err != nil {
+		logf("ipnserver.Run: %v", err)
+	}
+	return err
+}

cmd/tsshd/tsshd.go

@@ -32,7 +32,9 @@ import (
 	"github.com/gliderlabs/ssh"
 	"github.com/kr/pty"
 	gossh "golang.org/x/crypto/ssh"
+	"inet.af/netaddr"
 	"tailscale.com/net/interfaces"
+	"tailscale.com/net/tsaddr"
 )
 
 var (
@@ -96,7 +98,13 @@ func handleSSH(s ssh.Session) {
 		s.Exit(1)
 		return
 	}
-	if !interfaces.IsTailscaleIP(ta.IP) {
+	tanetaddr, ok := netaddr.FromStdIP(ta.IP)
+	if !ok {
+		log.Printf("tsshd: rejecting unparseable addr %v", ta.IP)
+		s.Exit(1)
+		return
+	}
+	if !tsaddr.IsTailscaleIP(tanetaddr) {
 		log.Printf("tsshd: rejecting non-Tailscale addr %v", ta.IP)
 		s.Exit(1)
 		return

control/controlclient/auto.go

@@ -18,10 +18,13 @@ import (
 	"time"
 
 	"golang.org/x/oauth2"
+	"tailscale.com/health"
 	"tailscale.com/logtail/backoff"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/empty"
 	"tailscale.com/types/logger"
+	"tailscale.com/types/netmap"
+	"tailscale.com/types/persist"
 	"tailscale.com/types/structs"
 	"tailscale.com/types/wgkey"
 )
@@ -68,9 +71,9 @@ type Status struct {
 	LoginFinished *empty.Message
 	Err           string
 	URL           string
-	Persist       *Persist          // locally persisted configuration
-	NetMap        *NetworkMap       // server-pushed configuration
-	Hostinfo      *tailcfg.Hostinfo // current Hostinfo data
+	Persist       *persist.Persist   // locally persisted configuration
+	NetMap        *netmap.NetworkMap // server-pushed configuration
+	Hostinfo      *tailcfg.Hostinfo  // current Hostinfo data
 	State         State
 }
 
@@ -114,6 +117,8 @@ type Client struct {
 	closed   bool
 	newMapCh chan struct{} // readable when we must restart a map request
 
+	unregisterHealthWatch func()
+
 	mu         sync.Mutex   // mutex guards the following fields
 	statusFunc func(Status) // called to update Client status
 
@@ -169,7 +174,14 @@ func NewNoStart(opts Options) (*Client, error) {
 	}
 	c.authCtx, c.authCancel = context.WithCancel(context.Background())
 	c.mapCtx, c.mapCancel = context.WithCancel(context.Background())
+	c.unregisterHealthWatch = health.RegisterWatcher(c.onHealthChange)
 	return c, nil
+
+}
+
+func (c *Client) onHealthChange(key string, err error) {
+	c.logf("controlclient: restarting map request for %q health change to new state: %v", key, err)
+	c.cancelMapSafely()
 }
 
 // SetPaused controls whether HTTP activity should be paused.
@@ -213,7 +225,7 @@ func (c *Client) sendNewMapRequest() {
 	// If we're not already streaming a netmap, or if we're already stuck
 	// in a lite update, then tear down everything and start a new stream
 	// (which starts by sending a new map request)
-	if !c.inPollNetMap || c.inLiteMapUpdate {
+	if !c.inPollNetMap || c.inLiteMapUpdate || !c.loggedIn {
 		c.mu.Unlock()
 		c.cancelMapSafely()
 		return
@@ -509,7 +521,7 @@ func (c *Client) mapRoutine() {
 			c.inPollNetMap = false
 			c.mu.Unlock()
 
-			err := c.direct.PollNetMap(ctx, -1, func(nm *NetworkMap) {
+			err := c.direct.PollNetMap(ctx, -1, func(nm *netmap.NetworkMap) {
 				c.mu.Lock()
 
 				select {
@@ -606,7 +618,7 @@ func (c *Client) SetNetInfo(ni *tailcfg.NetInfo) {
 	c.sendNewMapRequest()
 }
 
-func (c *Client) sendStatus(who string, err error, url string, nm *NetworkMap) {
+func (c *Client) sendStatus(who string, err error, url string, nm *netmap.NetworkMap) {
 	c.mu.Lock()
 	state := c.state
 	loggedIn := c.loggedIn
@@ -618,7 +630,7 @@ func (c *Client) sendStatus(who string, err error, url string, nm *NetworkMap) {
 
 	c.logf("[v1] sendStatus: %s: %v", who, state)
 
-	var p *Persist
+	var p *persist.Persist
 	var fin *empty.Message
 	if state == StateAuthenticated {
 		fin = new(empty.Message)
@@ -698,6 +710,7 @@ func (c *Client) Shutdown() {
 
 	c.logf("client.Shutdown: inSendStatus=%v", inSendStatus)
 	if !closed {
+		c.unregisterHealthWatch()
 		close(c.quit)
 		c.cancelAuth()
 		<-c.authDone

control/controlclient/direct.go

@@ -4,8 +4,6 @@
 
 package controlclient
 
-//go:generate go run tailscale.com/cmd/cloner -type=Persist -output=direct_clone.go
-
 import (
 	"bytes"
 	"context"
@@ -22,6 +20,7 @@ import (
 	"net/url"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"reflect"
 	"runtime"
 	"sort"
@@ -34,77 +33,24 @@ import (
 	"golang.org/x/crypto/nacl/box"
 	"golang.org/x/oauth2"
 	"inet.af/netaddr"
+	"tailscale.com/health"
 	"tailscale.com/log/logheap"
 	"tailscale.com/net/dnscache"
+	"tailscale.com/net/dnsfallback"
 	"tailscale.com/net/netns"
 	"tailscale.com/net/tlsdial"
 	"tailscale.com/net/tshttpproxy"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/logger"
+	"tailscale.com/types/netmap"
 	"tailscale.com/types/opt"
-	"tailscale.com/types/structs"
+	"tailscale.com/types/persist"
 	"tailscale.com/types/wgkey"
 	"tailscale.com/util/systemd"
 	"tailscale.com/version"
 	"tailscale.com/wgengine/filter"
 )
 
-type Persist struct {
-	_ structs.Incomparable
-
-	// LegacyFrontendPrivateMachineKey is here temporarily
-	// (starting 2020-09-28) during migration of Windows users'
-	// machine keys from frontend storage to the backend. On the
-	// first LocalBackend.Start call, the backend will initialize
-	// the real (backend-owned) machine key from the frontend's
-	// provided value (if non-zero), picking a new random one if
-	// needed. This field should be considered read-only from GUI
-	// frontends. The real value should not be written back in
-	// this field, lest the frontend persist it to disk.
-	LegacyFrontendPrivateMachineKey wgkey.Private `json:"PrivateMachineKey"`
-
-	PrivateNodeKey    wgkey.Private
-	OldPrivateNodeKey wgkey.Private // needed to request key rotation
-	Provider          string
-	LoginName         string
-}
-
-func (p *Persist) Equals(p2 *Persist) bool {
-	if p == nil && p2 == nil {
-		return true
-	}
-	if p == nil || p2 == nil {
-		return false
-	}
-
-	return p.LegacyFrontendPrivateMachineKey.Equal(p2.LegacyFrontendPrivateMachineKey) &&
-		p.PrivateNodeKey.Equal(p2.PrivateNodeKey) &&
-		p.OldPrivateNodeKey.Equal(p2.OldPrivateNodeKey) &&
-		p.Provider == p2.Provider &&
-		p.LoginName == p2.LoginName
-}
-
-func (p *Persist) Pretty() string {
-	var mk, ok, nk wgkey.Key
-	if !p.LegacyFrontendPrivateMachineKey.IsZero() {
-		mk = p.LegacyFrontendPrivateMachineKey.Public()
-	}
-	if !p.OldPrivateNodeKey.IsZero() {
-		ok = p.OldPrivateNodeKey.Public()
-	}
-	if !p.PrivateNodeKey.IsZero() {
-		nk = p.PrivateNodeKey.Public()
-	}
-	ss := func(k wgkey.Key) string {
-		if k.IsZero() {
-			return ""
-		}
-		return k.ShortString()
-	}
-	return fmt.Sprintf("Persist{lm=%v, o=%v, n=%v u=%#v}",
-		ss(mk), ss(ok), ss(nk), p.LoginName)
-}
-
 // Direct is the client that connects to a tailcontrol server for a node.
 type Direct struct {
 	httpc                  *http.Client // HTTP client used to talk to tailcontrol
@@ -121,7 +67,7 @@ type Direct struct {
 
 	mu           sync.Mutex // mutex guards the following fields
 	serverKey    wgkey.Key
-	persist      Persist
+	persist      persist.Persist
 	authKey      string
 	tryingNewKey wgkey.Private
 	expiry       *time.Time
@@ -133,7 +79,7 @@ type Direct struct {
 }
 
 type Options struct {
-	Persist           Persist           // initial persistent data
+	Persist           persist.Persist   // initial persistent data
 	MachinePrivateKey wgkey.Private     // the machine key to use
 	ServerURL         string            // URL of the tailcontrol server
 	AuthKey           string            // optional node auth key for auto registration
@@ -181,16 +127,18 @@ func NewDirect(opts Options) (*Direct, error) {
 	httpc := opts.HTTPTestClient
 	if httpc == nil {
 		dnsCache := &dnscache.Resolver{
-			Forward:     dnscache.Get().Forward, // use default cache's forwarder
-			UseLastGood: true,
+			Forward:          dnscache.Get().Forward, // use default cache's forwarder
+			UseLastGood:      true,
+			LookupIPFallback: dnsfallback.Lookup,
 		}
 		dialer := netns.NewDialer()
 		tr := http.DefaultTransport.(*http.Transport).Clone()
 		tr.Proxy = tshttpproxy.ProxyFromEnvironment
 		tshttpproxy.SetTransportGetProxyConnectHeader(tr)
-		tr.DialContext = dnscache.Dialer(dialer.DialContext, dnsCache)
-		tr.ForceAttemptHTTP2 = true
 		tr.TLSClientConfig = tlsdial.Config(serverURL.Host, tr.TLSClientConfig)
+		tr.DialContext = dnscache.Dialer(dialer.DialContext, dnsCache)
+		tr.DialTLSContext = dnscache.TLSDialer(dialer.DialContext, dnsCache, tr.TLSClientConfig)
+		tr.ForceAttemptHTTP2 = true
 		httpc = &http.Client{Transport: tr}
 	}
 
@@ -229,10 +177,25 @@ func NewHostinfo() *tailcfg.Hostinfo {
 		Hostname:   hostname,
 		OS:         version.OS(),
 		OSVersion:  osv,
+		Package:    packageType(),
 		GoArch:     runtime.GOARCH,
 	}
 }
 
+func packageType() string {
+	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)
+	}
+	return ""
+}
+
 // 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 {
@@ -271,7 +234,7 @@ func (c *Direct) SetNetInfo(ni *tailcfg.NetInfo) bool {
 	return true
 }
 
-func (c *Direct) GetPersist() Persist {
+func (c *Direct) GetPersist() persist.Persist {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	return c.persist
@@ -294,7 +257,7 @@ func (c *Direct) TryLogout(ctx context.Context) error {
 	// immediately invalidated.
 	//if !c.persist.PrivateNodeKey.IsZero() {
 	//}
-	c.persist = Persist{}
+	c.persist = persist.Persist{}
 	return nil
 }
 
@@ -526,7 +489,7 @@ func inTest() bool { return flag.Lookup("test.v") != nil }
 //
 // maxPolls is how many network maps to download; common values are 1
 // or -1 (to keep a long-poll query open to the server).
-func (c *Direct) PollNetMap(ctx context.Context, maxPolls int, cb func(*NetworkMap)) error {
+func (c *Direct) PollNetMap(ctx context.Context, maxPolls int, cb func(*netmap.NetworkMap)) error {
 	return c.sendMapRequest(ctx, maxPolls, cb)
 }
 
@@ -538,7 +501,7 @@ func (c *Direct) SendLiteMapUpdate(ctx context.Context) error {
 }
 
 // cb nil means to omit peers.
-func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*NetworkMap)) error {
+func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netmap.NetworkMap)) error {
 	c.mu.Lock()
 	persist := c.persist
 	serverURL := c.serverURL
@@ -550,6 +513,9 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*Netw
 	everEndpoints := c.everEndpoints
 	c.mu.Unlock()
 
+	if persist.PrivateNodeKey.IsZero() {
+		return errors.New("privateNodeKey is zero")
+	}
 	if backendLogID == "" {
 		return errors.New("hostinfo: BackendLogID missing")
 	}
@@ -575,9 +541,16 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*Netw
 		DebugFlags: c.debugFlags,
 		OmitPeers:  cb == nil,
 	}
+	var extraDebugFlags []string
 	if hostinfo != nil && ipForwardingBroken(hostinfo.RoutableIPs) {
+		extraDebugFlags = append(extraDebugFlags, "warn-ip-forwarding-off")
+	}
+	if health.RouterHealth() != nil {
+		extraDebugFlags = append(extraDebugFlags, "warn-router-unhealthy")
+	}
+	if len(extraDebugFlags) > 0 {
 		old := request.DebugFlags
-		request.DebugFlags = append(old[:len(old):len(old)], "warn-ip-forwarding-off")
+		request.DebugFlags = append(old[:len(old):len(old)], extraDebugFlags...)
 	}
 	if c.newDecompressor != nil {
 		request.Compress = "zstd"
@@ -744,6 +717,14 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*Netw
 			}
 			resp.Peers = filtered
 		}
+		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"}
+			}
+		}
 
 		if pf := resp.PacketFilter; pf != nil {
 			lastParsedPacketFilter = c.parsePacketFilter(pf)
@@ -761,7 +742,8 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*Netw
 		localPort = c.localPort
 		c.mu.Unlock()
 
-		nm := &NetworkMap{
+		nm := &netmap.NetworkMap{
+			SelfNode:        resp.Node,
 			NodeKey:         tailcfg.NodeKey(persist.PrivateNodeKey.Public()),
 			PrivateKey:      persist.PrivateNodeKey,
 			MachineKey:      machinePubKey,
@@ -790,7 +772,10 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*Netw
 			}
 		}
 		addUserProfile(nm.User)
+		magicDNSSuffix := nm.MagicDNSSuffix()
+		nm.SelfNode.InitDisplayNames(magicDNSSuffix)
 		for _, peer := range resp.Peers {
+			peer.InitDisplayNames(magicDNSSuffix)
 			if !peer.Sharer.IsZero() {
 				if c.keepSharerAndUserSplit {
 					addUserProfile(peer.Sharer)
@@ -972,19 +957,21 @@ func loadServerKey(ctx context.Context, httpc *http.Client, serverURL string) (w
 var Debug = initDebug()
 
 type debug struct {
-	NetMap    bool
-	ProxyDNS  bool
-	OnlyDisco bool
-	Disco     bool
+	NetMap         bool
+	ProxyDNS       bool
+	OnlyDisco      bool
+	Disco          bool
+	StripEndpoints bool // strip endpoints from control (only use disco messages)
 }
 
 func initDebug() debug {
 	use := os.Getenv("TS_DEBUG_USE_DISCO")
 	return debug{
-		NetMap:    envBool("TS_DEBUG_NETMAP"),
-		ProxyDNS:  envBool("TS_DEBUG_PROXY_DNS"),
-		OnlyDisco: use == "only",
-		Disco:     use == "only" || use == "" || envBool("TS_DEBUG_USE_DISCO"),
+		NetMap:         envBool("TS_DEBUG_NETMAP"),
+		ProxyDNS:       envBool("TS_DEBUG_PROXY_DNS"),
+		StripEndpoints: envBool("TS_DEBUG_STRIP_ENDPOINTS"),
+		OnlyDisco:      use == "only",
+		Disco:          use == "only" || use == "" || envBool("TS_DEBUG_USE_DISCO"),
 	}
 }
 
@@ -1065,6 +1052,24 @@ func undeltaPeers(mapRes *tailcfg.MapResponse, prev []*tailcfg.Node) {
 		}
 	}
 	sortNodes(newFull)
+
+	if mapRes.PeerSeenChange != nil {
+		peerByID := make(map[tailcfg.NodeID]*tailcfg.Node, len(newFull))
+		for _, n := range newFull {
+			peerByID[n.ID] = n
+		}
+		now := time.Now()
+		for nodeID, seen := range mapRes.PeerSeenChange {
+			if n, ok := peerByID[nodeID]; ok {
+				if seen {
+					n.LastSeen = &now
+				} else {
+					n.LastSeen = nil
+				}
+			}
+		}
+	}
+
 	mapRes.Peers = newFull
 	mapRes.PeersChanged = nil
 	mapRes.PeersRemoved = nil

control/controlclient/direct_clone.go

@@ -1,20 +0,0 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Code generated by tailscale.com/cmd/cloner -type Persist; DO NOT EDIT.
-
-package controlclient
-
-import ()
-
-// Clone makes a deep copy of Persist.
-// The result aliases no memory with the original.
-func (src *Persist) Clone() *Persist {
-	if src == nil {
-		return nil
-	}
-	dst := new(Persist)
-	*dst = *src
-	return dst
-}

control/controlclient/direct_test.go

@@ -5,6 +5,7 @@
 package controlclient
 
 import (
+	"encoding/json"
 	"fmt"
 	"reflect"
 	"strings"
@@ -156,3 +157,15 @@ func TestNewDirect(t *testing.T) {
 		t.Errorf("c.newEndpoints(13) want true got %v", changed)
 	}
 }
+
+func TestNewHostinfo(t *testing.T) {
+	hi := NewHostinfo()
+	if hi == nil {
+		t.Fatal("no Hostinfo")
+	}
+	j, err := json.MarshalIndent(hi, "  ", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("Got: %s", j)
+}

derp/derphttp/derphttp_client.go

@@ -709,10 +709,19 @@ func (c *Client) RecvDetail() (m derp.ReceivedMessage, connGen int, err error) {
 	m, err = client.Recv()
 	if err != nil {
 		c.closeForReconnect(client)
+		if c.isClosed() {
+			err = ErrClientClosed
+		}
 	}
 	return m, connGen, err
 }
 
+func (c *Client) isClosed() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.closed
+}
+
 // Close closes the client. It will not automatically reconnect after
 // being closed.
 func (c *Client) Close() error {

derp/derphttp/mesh_client.go

@@ -5,20 +5,32 @@
 package derphttp
 
 import (
+	"context"
 	"sync"
 	"time"
 
 	"tailscale.com/derp"
 	"tailscale.com/types/key"
+	"tailscale.com/types/logger"
 )
 
-// RunWatchConnectionLoop loops forever, sending WatchConnectionChanges and subscribing to
+// RunWatchConnectionLoop loops until ctx is done, sending WatchConnectionChanges and subscribing to
 // connection changes.
 //
 // If the server's public key is ignoreServerKey, RunWatchConnectionLoop returns.
 //
 // Otherwise, the add and remove funcs are called as clients come & go.
-func (c *Client) RunWatchConnectionLoop(ignoreServerKey key.Public, add, remove func(key.Public)) {
+//
+// infoLogf, if non-nil, is the logger to write periodic status
+// updates about how many peers are on the server. Error log output is
+// set to the c's logger, regardless of infoLogf's value.
+//
+// To force RunWatchConnectionLoop to return quickly, its ctx needs to
+// be closed, and c itself needs to be closed.
+func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key.Public, infoLogf logger.Logf, add, remove func(key.Public)) {
+	if infoLogf == nil {
+		infoLogf = logger.Discard
+	}
 	logf := c.logf
 	const retryInterval = 5 * time.Second
 	const statusInterval = 10 * time.Second
@@ -45,7 +57,7 @@ func (c *Client) RunWatchConnectionLoop(ignoreServerKey key.Public, add, remove
 		if loggedConnected {
 			return
 		}
-		logf("connected; %d peers", len(present))
+		infoLogf("connected; %d peers", len(present))
 		loggedConnected = true
 	}
 
@@ -79,12 +91,21 @@ func (c *Client) RunWatchConnectionLoop(ignoreServerKey key.Public, add, remove
 		}
 	}
 
-	for {
+	sleep := func(d time.Duration) {
+		t := time.NewTimer(d)
+		select {
+		case <-ctx.Done():
+			t.Stop()
+		case <-t.C:
+		}
+	}
+
+	for ctx.Err() == nil {
 		err := c.WatchConnectionChanges()
 		if err != nil {
 			clear()
 			logf("WatchConnectionChanges: %v", err)
-			time.Sleep(retryInterval)
+			sleep(retryInterval)
 			continue
 		}
 
@@ -97,7 +118,7 @@ func (c *Client) RunWatchConnectionLoop(ignoreServerKey key.Public, add, remove
 			if err != nil {
 				clear()
 				logf("Recv: %v", err)
-				time.Sleep(retryInterval)
+				sleep(retryInterval)
 				break
 			}
 			if connGen != lastConnGen {
@@ -114,9 +135,8 @@ func (c *Client) RunWatchConnectionLoop(ignoreServerKey key.Public, add, remove
 			}
 			if now := time.Now(); now.Sub(lastStatus) > statusInterval {
 				lastStatus = now
-				logf("%d peers", len(present))
+				infoLogf("%d peers", len(present))
 			}
 		}
 	}
-
 }

disco/disco.go

@@ -70,7 +70,7 @@ func Parse(p []byte) (Message, error) {
 	case TypePong:
 		return parsePong(ver, p)
 	case TypeCallMeMaybe:
-		return CallMeMaybe{}, nil
+		return parseCallMeMaybe(ver, p)
 	default:
 		return nil, fmt.Errorf("unknown message type 0x%02x", byte(t))
 	}
@@ -122,13 +122,57 @@ func parsePing(ver uint8, p []byte) (m *Ping, err error) {
 //
 // The recipient may choose to not open a path back, if it's already
 // happy with its path. But usually it will.
-type CallMeMaybe struct{}
+type CallMeMaybe struct {
+	// MyNumber is what the peer believes its endpoints are.
+	//
+	// Prior to Tailscale 1.4, the endpoints were exchanged purely
+	// between nodes and the control server.
+	//
+	// Starting with Tailscale 1.4, clients advertise their endpoints.
+	// Older clients won't use this, but newer clients should
+	// use any endpoints in here that aren't included from control.
+	//
+	// Control might have sent stale endpoints if the client was idle
+	// before contacting us. In that case, the client likely did a STUN
+	// request immediately before sending the CallMeMaybe to recreate
+	// their NAT port mapping, and that new good endpoint is included
+	// in this field, but might not yet be in control's endpoints.
+	// (And in the future, control will stop distributing endpoints
+	// when clients are suitably new.)
+	MyNumber []netaddr.IPPort
+}
 
-func (CallMeMaybe) AppendMarshal(b []byte) []byte {
-	ret, _ := appendMsgHeader(b, TypeCallMeMaybe, v0, 0)
+const epLength = 16 + 2 // 16 byte IP address + 2 byte port
+
+func (m *CallMeMaybe) AppendMarshal(b []byte) []byte {
+	ret, p := appendMsgHeader(b, TypeCallMeMaybe, v0, epLength*len(m.MyNumber))
+	for _, ipp := range m.MyNumber {
+		a := ipp.IP.As16()
+		copy(p[:], a[:])
+		binary.BigEndian.PutUint16(p[16:], ipp.Port)
+		p = p[epLength:]
+	}
 	return ret
 }
 
+func parseCallMeMaybe(ver uint8, p []byte) (m *CallMeMaybe, err error) {
+	m = new(CallMeMaybe)
+	if len(p)%epLength != 0 || ver != 0 || len(p) == 0 {
+		return m, nil
+	}
+	m.MyNumber = make([]netaddr.IPPort, 0, len(p)/epLength)
+	for len(p) > 0 {
+		var a [16]byte
+		copy(a[:], p)
+		m.MyNumber = append(m.MyNumber, netaddr.IPPort{
+			IP:   netaddr.IPFrom16(a),
+			Port: binary.BigEndian.Uint16(p[16:18]),
+		})
+		p = p[epLength:]
+	}
+	return m, nil
+}
+
 // Pong is a response a Ping.
 //
 // It includes the sender's source IP + port, so it's effectively a
@@ -171,7 +215,7 @@ func MessageSummary(m Message) string {
 		return fmt.Sprintf("ping tx=%x", m.TxID[:6])
 	case *Pong:
 		return fmt.Sprintf("pong tx=%x", m.TxID[:6])
-	case CallMeMaybe:
+	case *CallMeMaybe:
 		return "call-me-maybe"
 	default:
 		return fmt.Sprintf("%#v", m)

disco/disco_test.go

@@ -44,9 +44,19 @@ func TestMarshalAndParse(t *testing.T) {
 		},
 		{
 			name: "call_me_maybe",
-			m:    CallMeMaybe{},
+			m:    &CallMeMaybe{},
 			want: "03 00",
 		},
+		{
+			name: "call_me_maybe_endpoints",
+			m: &CallMeMaybe{
+				MyNumber: []netaddr.IPPort{
+					netaddr.MustParseIPPort("1.2.3.4:567"),
+					netaddr.MustParseIPPort("[2001::3456]:789"),
+				},
+			},
+			want: "03 00 00 00 00 00 00 00 00 00 00 00 ff ff 01 02 03 04 02 37 20 01 00 00 00 00 00 00 00 00 00 00 00 00 34 56 03 15",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

go.mod

@@ -1,6 +1,6 @@
 module tailscale.com
 
-go 1.15
+go 1.16
 
 require (
 	github.com/alexbrainman/sspi v0.0.0-20180613141037-e580b900e9f5
@@ -15,30 +15,31 @@ require (
 	github.com/golang/protobuf v1.4.2 // indirect
 	github.com/google/go-cmp v0.5.4
 	github.com/goreleaser/nfpm v1.1.10
-	github.com/jsimonetti/rtnetlink v0.0.0-20201216134343-bde56ed16391
+	github.com/jsimonetti/rtnetlink v0.0.0-20210212075122-66c871082f2b
 	github.com/klauspost/compress v1.10.10
-	github.com/kr/pty v1.1.4-0.20190131011033-7dc38fb350b1
-	github.com/mdlayher/netlink v1.2.0
+	github.com/kr/pty v1.1.8
+	github.com/mdlayher/netlink v1.3.2
 	github.com/mdlayher/sdnotify v0.0.0-20200625151349-e4a4f32afc4a
 	github.com/miekg/dns v1.1.30
 	github.com/pborman/getopt v0.0.0-20190409184431-ee0cd42419d3
 	github.com/peterbourgon/ff/v2 v2.0.0
 	github.com/tailscale/depaware v0.0.0-20201214215404-77d1e9757027
-	github.com/tailscale/wireguard-go v0.0.0-20210116013233-4cd297ed5a7d
+	github.com/tailscale/wireguard-go v0.0.0-20210210202228-3cc76ed5f222
 	github.com/tcnksm/go-httpstat v0.2.0
 	github.com/toqueteos/webbrowser v1.2.0
 	go4.org/mem v0.0.0-20201119185036-c04c5a6ff174
-	golang.org/x/crypto v0.0.0-20201124201722-c8d3bf9c5392
-	golang.org/x/net v0.0.0-20201216054612-986b41b23924
+	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad
+	golang.org/x/net v0.0.0-20210220033124-5f55cee0dc0d
 	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
 	golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9
-	golang.org/x/sys v0.0.0-20201218084310-7d0127a74742
+	golang.org/x/sys v0.0.0-20210220050731-9a76102bfb43
 	golang.org/x/term v0.0.0-20201207232118-ee85cb95a76b
 	golang.org/x/time v0.0.0-20191024005414-555d28b269f0
 	golang.org/x/tools v0.0.0-20201211185031-d93e913c1a58
 	golang.zx2c4.com/wireguard/windows v0.1.2-0.20201113162609-9b85be97fdf8
 	gvisor.dev/gvisor v0.0.0-20210111185822-3ff3110fcdd6
 	honnef.co/go/tools v0.1.0
-	inet.af/netaddr v0.0.0-20210105212526-648fbc18a69d
+	inet.af/netaddr v0.0.0-20210222205655-a1ec2b7b8c44
+	inet.af/peercred v0.0.0-20210216231719-993aa01eacaa
 	rsc.io/goversion v1.2.0
 )

go.sum

@@ -68,6 +68,8 @@ github.com/coreos/go-systemd/v22 v22.0.0/go.mod h1:xO0FLkIi5MaZafQlIrOotqXZ90ih+
 github.com/coreos/go-systemd/v22 v22.1.0/go.mod h1:xO0FLkIi5MaZafQlIrOotqXZ90ih+1atmu1JpKERPPk=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
+github.com/creack/pty v1.1.7 h1:6pwm8kMQKCmgUg0ZHTm5+/YvRK0s3THD/28+T6/kk4A=
+github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
 github.com/davecgh/go-spew v0.0.0-20151105211317-5215b55f46b2/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -121,7 +123,6 @@ github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfb
 github.com/golang/mock v1.2.0/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/mock v1.3.1/go.mod h1:sBzyDLLjw3U8JLTeZvSv8jJB+tU5PVekmnlKIyFUx0Y=
 github.com/golang/protobuf v0.0.0-20161109072736-4bd1920723d7/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
-github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
@@ -140,9 +141,7 @@ github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
-github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.0 h1:/QaMHBdZ26BB3SSst0Iwl10Epc+xhTquomWX0oZEB6w=
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.3-0.20201020212313-ab46b8bd0abd/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
@@ -179,12 +178,16 @@ github.com/imdario/mergo v0.3.5/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJ
 github.com/imdario/mergo v0.3.8 h1:CGgOkSJeqMRmt0D9XLWExdT4m4F1vd3FV3VPt+0VxkQ=
 github.com/imdario/mergo v0.3.8/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
+github.com/josharian/native v0.0.0-20200817173448-b6b71def0850 h1:uhL5Gw7BINiiPAo24A2sxkcDI0Jt/sqp1v5xQCniEFA=
+github.com/josharian/native v0.0.0-20200817173448-b6b71def0850/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
 github.com/jsimonetti/rtnetlink v0.0.0-20190606172950-9527aa82566a/go.mod h1:Oz+70psSo5OFh8DBl0Zv2ACw7Esh6pPUphlvZG9x7uw=
-github.com/jsimonetti/rtnetlink v0.0.0-20200117123717-f846d4f6c1f4 h1:nwOc1YaOrYJ37sEBrtWZrdqzK22hiJs3GpDmP3sR2Yw=
 github.com/jsimonetti/rtnetlink v0.0.0-20200117123717-f846d4f6c1f4/go.mod h1:WGuG/smIU4J/54PblvSbh+xvCZmpJnFgr3ds6Z55XMQ=
 github.com/jsimonetti/rtnetlink v0.0.0-20201009170750-9c6f07d100c1/go.mod h1:hqoO/u39cqLeBLebZ8fWdE96O7FxrAsRYhnVOdgHxok=
-github.com/jsimonetti/rtnetlink v0.0.0-20201216134343-bde56ed16391 h1:Dqu/4JhMV1vpXHDjzQCuDCEsjNi0xfuSmQlMOyqayKA=
 github.com/jsimonetti/rtnetlink v0.0.0-20201216134343-bde56ed16391/go.mod h1:cR77jAZG3Y3bsb8hF6fHJbFoyFukLFOkQ98S0pQz3xw=
+github.com/jsimonetti/rtnetlink v0.0.0-20201220180245-69540ac93943/go.mod h1:z4c53zj6Eex712ROyh8WI0ihysb5j2ROyV42iNogmAs=
+github.com/jsimonetti/rtnetlink v0.0.0-20210122163228-8d122574c736/go.mod h1:ZXpIyOK59ZnN7J0BV99cZUPmsqDRZ3eq5X+st7u/oSA=
+github.com/jsimonetti/rtnetlink v0.0.0-20210212075122-66c871082f2b h1:c3NTyLNozICy8B4mlMXemD3z/gXgQzVXZS/HqT+i3do=
+github.com/jsimonetti/rtnetlink v0.0.0-20210212075122-66c871082f2b/go.mod h1:8w9Rh8m+aHZIG69YPGGem1i5VzoyRC8nw2kA8B+ik5U=
 github.com/json-iterator/go v0.0.0-20180612202835-f2b4162afba3/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.7/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/jstemmer/go-junit-report v0.0.0-20190106144839-af01ea7f8024/go.mod h1:6v2b51hI/fHJwM22ozAgKL4VKDeJcHhJFhtBdhmNjmU=
@@ -198,10 +201,10 @@ github.com/konsorten/go-windows-terminal-sequences v1.0.2/go.mod h1:T0+1ngSBFLxv
 github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
-github.com/kr/pty v1.1.1 h1:VkoXIwSboBpnk99O/KFauAEILuNHv5DVFKZMBN/gUgw=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
-github.com/kr/pty v1.1.4-0.20190131011033-7dc38fb350b1 h1:zc0R6cOw98cMengLA0fvU55mqbnN7sd/tBMLzSejp+M=
 github.com/kr/pty v1.1.4-0.20190131011033-7dc38fb350b1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/pty v1.1.8 h1:AkaSdXYQOWeaO3neb8EM634ahkXXe3jYbVh/F9lq+GI=
+github.com/kr/pty v1.1.8/go.mod h1:O1sed60cT9XZ5uDucP5qwvh+TE3NnUj51EiZO/lmSfw=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/lxn/walk v0.0.0-20201110160827-18ea5e372cdb/go.mod h1:E23UucZGqpuUANJooIbHWCufXvOcT6E7Stq81gU+CSQ=
@@ -210,13 +213,20 @@ github.com/mailru/easyjson v0.0.0-20160728113105-d5b7844b561a/go.mod h1:C1wdFJiN
 github.com/mattbaird/jsonpatch v0.0.0-20171005235357-81af80346b1a/go.mod h1:M1qoD/MqPgTZIk0EWKB38wE28ACRfVcn+cU08jyArI0=
 github.com/mattn/go-zglob v0.0.1 h1:xsEx/XUoVlI6yXjqBK062zYhRTZltCNmYPx6v+8DNaY=
 github.com/mattn/go-zglob v0.0.1/go.mod h1:9fxibJccNxU2cnpIKLRRFA7zX7qhkJIQWBb449FYHOo=
+github.com/mdlayher/ethtool v0.0.0-20210210192532-2b88debcdd43 h1:WgyLFv10Ov49JAQI/ZLUkCZ7VJS3r74hwFIGXJsgZlY=
+github.com/mdlayher/ethtool v0.0.0-20210210192532-2b88debcdd43/go.mod h1:+t7E0lkKfbBsebllff1xdTmyJt8lH37niI6kwFk9OTo=
+github.com/mdlayher/genetlink v1.0.0 h1:OoHN1OdyEIkScEmRgxLEe2M9U8ClMytqA5niynLtfj0=
+github.com/mdlayher/genetlink v1.0.0/go.mod h1:0rJ0h4itni50A86M2kHcgS85ttZazNt7a8H2a2cw0Gc=
 github.com/mdlayher/netlink v0.0.0-20190409211403-11939a169225/go.mod h1:eQB3mZE4aiYnlUsyGGCOpPETfdQq4Jhsgf1fk3cwQaA=
 github.com/mdlayher/netlink v1.0.0/go.mod h1:KxeJAFOFLG6AjpyDkQ/iIhxygIUKD+vcwqcnu43w/+M=
-github.com/mdlayher/netlink v1.1.0 h1:mpdLgm+brq10nI9zM1BpX1kpDbh3NLl3RSnVq6ZSkfg=
 github.com/mdlayher/netlink v1.1.0/go.mod h1:H4WCitaheIsdF9yOYu8CFmCgQthAPIWZmcKp9uZHgmY=
 github.com/mdlayher/netlink v1.1.1/go.mod h1:WTYpFb/WTvlRJAyKhZL5/uy69TDDpHHu2VZmb2XgV7o=
-github.com/mdlayher/netlink v1.2.0 h1:zPolhRjfuabdf8ofZsl56eoU+92cvSlAn13lw4veCZ0=
 github.com/mdlayher/netlink v1.2.0/go.mod h1:kwVW1io0AZy9A1E2YYgaD4Cj+C+GPkU6klXCMzIJ9p8=
+github.com/mdlayher/netlink v1.2.1/go.mod h1:bacnNlfhqHqqLo4WsYeXSqfyXkInQ9JneWI68v1KwSU=
+github.com/mdlayher/netlink v1.2.2-0.20210123213345-5cc92139ae3e/go.mod h1:bacnNlfhqHqqLo4WsYeXSqfyXkInQ9JneWI68v1KwSU=
+github.com/mdlayher/netlink v1.3.0/go.mod h1:xK/BssKuwcRXHrtN04UBkwQ6dY9VviGGuriDdoPSWys=
+github.com/mdlayher/netlink v1.3.2 h1:fMZOU2/M7PRMzGM3br5l1N2fu6bPSHtRytmQ338a9iA=
+github.com/mdlayher/netlink v1.3.2/go.mod h1:dRJi5IABcZpBD2A3D0Mv/AiX8I9uDEu5oGkAVrekmf8=
 github.com/mdlayher/sdnotify v0.0.0-20200625151349-e4a4f32afc4a h1:wMv2mvcHRH4jqIxaVL5t6gSq1hjPiaWH7TOcA0Z+uNo=
 github.com/mdlayher/sdnotify v0.0.0-20200625151349-e4a4f32afc4a/go.mod h1:HtjVsQfsrBm1GDcDTUFn4ZXhftxTwO/hxrvEiRc61U4=
 github.com/miekg/dns v1.1.30 h1:Qww6FseFn8PRfw07jueqIXqodm0JKiiKuK0DeXSqfyo=
@@ -251,7 +261,6 @@ github.com/peterbourgon/ff/v2 v2.0.0 h1:lx0oYI5qr/FU1xnpNhQ+EZM04gKgn46jyYvGEEqB
 github.com/peterbourgon/ff/v2 v2.0.0/go.mod h1:xjwr+t+SjWm4L46fcj/D+Ap+6ME7+HqFzaP22pP5Ggk=
 github.com/pkg/diff v0.0.0-20200914180035-5b29258ca4f7 h1:+/+DxvQaYifJ+grD4klzrS5y+KJXldn/2YTl5JG+vZ8=
 github.com/pkg/diff v0.0.0-20200914180035-5b29258ca4f7/go.mod h1:zO8QMzTeZd5cpnIkz/Gn6iK0jDfGicM1nynOkkPIl28=
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
@@ -286,14 +295,8 @@ github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81P
 github.com/syndtr/gocapability v0.0.0-20180916011248-d98352740cb2/go.mod h1:hkRG7XYTFWNJGYcbNJQlaLq0fg1yr4J4t/NcTQtrfww=
 github.com/tailscale/depaware v0.0.0-20201214215404-77d1e9757027 h1:lK99QQdH3yBWY6aGilF+IRlQIdmhzLrsEmF6JgN+Ryw=
 github.com/tailscale/depaware v0.0.0-20201214215404-77d1e9757027/go.mod h1:p9lPsd+cx33L3H9nNoecRRxPssFKUwwI50I3pZ0yT+8=
-github.com/tailscale/wireguard-go v0.0.0-20210109012254-dc30a1b9415e h1:ZXbXfVJOhSq4/Gt7TnqwXBPCctzYXkWXo3oQS7LZ40I=
-github.com/tailscale/wireguard-go v0.0.0-20210109012254-dc30a1b9415e/go.mod h1:K/wyv4+3PcdVVTV7szyoiEjJ1nVHonM8cJ2mQwG5Fl8=
-github.com/tailscale/wireguard-go v0.0.0-20210113223737-a6213b5eaf98 h1:khwYPK1eT+4pmEFyCjpf6Br/0JWjdVT3uQ+ILFJPTRo=
-github.com/tailscale/wireguard-go v0.0.0-20210113223737-a6213b5eaf98/go.mod h1:K/wyv4+3PcdVVTV7szyoiEjJ1nVHonM8cJ2mQwG5Fl8=
-github.com/tailscale/wireguard-go v0.0.0-20210114205708-a1377e83f551 h1:hjBVxvVa145kVflAFkVcTr/zwUzBO4SqfSS6xhbcMv8=
-github.com/tailscale/wireguard-go v0.0.0-20210114205708-a1377e83f551/go.mod h1:K/wyv4+3PcdVVTV7szyoiEjJ1nVHonM8cJ2mQwG5Fl8=
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-github.com/tailscale/wireguard-go v0.0.0-20210116013233-4cd297ed5a7d/go.mod h1:K/wyv4+3PcdVVTV7szyoiEjJ1nVHonM8cJ2mQwG5Fl8=
+github.com/tailscale/wireguard-go v0.0.0-20210210202228-3cc76ed5f222 h1:VzTS7LIwCH8jlxwrZguU0TsCLV/MDOunoNIDJdFajyM=
+github.com/tailscale/wireguard-go v0.0.0-20210210202228-3cc76ed5f222/go.mod h1:6t0OVdJwFOKFnvaHaVMKG6GznWaHqkmiR2n3kH0t924=
 github.com/tcnksm/go-httpstat v0.2.0 h1:rP7T5e5U2HfmOBmZzGgGZjBQ5/GluWUylujl0tJ04I0=
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@@ -312,15 +315,12 @@ go.opencensus.io v0.22.0/go.mod h1:+kGneAE2xo2IficOXnaByMWTGM9T73dGwxeWcUqIpI8=
 go.opencensus.io v0.22.2/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=
-go4.org/intern v0.0.0-20201223054237-ef8cbcb8edd7 h1:yeDrXaQ3VRXbTN7lHj70DxW4LdPow83MVwPPRjpP70U=
-go4.org/intern v0.0.0-20201223054237-ef8cbcb8edd7/go.mod h1:vLqJ+12kCw61iCWsPto0EOHhBS+o4rO5VIucbc9g2Cc=
-go4.org/intern v0.0.0-20201223061701-969c7e87e7cb h1:yuqO0E4bHRsTPUocDpRKXfLE40lwWplVxENQ2WOV7Gc=
-go4.org/intern v0.0.0-20201223061701-969c7e87e7cb/go.mod h1:vLqJ+12kCw61iCWsPto0EOHhBS+o4rO5VIucbc9g2Cc=
 go4.org/intern v0.0.0-20210101010959-7cab76ca296a h1:28p852HIWWaOS019DYK/A3yTmpm1HJaUce63pvll4C8=
 go4.org/intern v0.0.0-20210101010959-7cab76ca296a/go.mod h1:vLqJ+12kCw61iCWsPto0EOHhBS+o4rO5VIucbc9g2Cc=
+go4.org/intern v0.0.0-20210108033219-3eb7198706b2 h1:VFTf+jjIgsldaz/Mr00VaCSswHJrI2hIjQygE/W4IMg=
+go4.org/intern v0.0.0-20210108033219-3eb7198706b2/go.mod h1:vLqJ+12kCw61iCWsPto0EOHhBS+o4rO5VIucbc9g2Cc=
 go4.org/mem v0.0.0-20201119185036-c04c5a6ff174 h1:vSug/WNOi2+4jrKdivxayTN/zd8EA1UrStjpWvvo1jk=
 go4.org/mem v0.0.0-20201119185036-c04c5a6ff174/go.mod h1:reUoABIJ9ikfM5sgtSF3Wushcza7+WeD01VB9Lirh3g=
-go4.org/unsafe/assume-no-moving-gc v0.0.0-20201222175341-b30ae309168e h1:ExUmGi0ZsQmiVo9giDQqXkr7vreeXPMkOGIusfsfbzI=
 go4.org/unsafe/assume-no-moving-gc v0.0.0-20201222175341-b30ae309168e/go.mod h1:FftLjUGFEDu5k8lt0ddY+HcrH/qU/0qk+H8j9/nTl3E=
 go4.org/unsafe/assume-no-moving-gc v0.0.0-20201222180813-1025295fd063 h1:1tk03FUNpulq2cuWpXZWj649rwJpk0d20rxWiopKRmc=
 go4.org/unsafe/assume-no-moving-gc v0.0.0-20201222180813-1025295fd063/go.mod h1:FftLjUGFEDu5k8lt0ddY+HcrH/qU/0qk+H8j9/nTl3E=
@@ -334,8 +334,8 @@ golang.org/x/crypto v0.0.0-20200220183623-bac4c82f6975/go.mod h1:LzIPMQfyMNhhGPh
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20201112155050-0c6587e931a9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.0.0-20201124201722-c8d3bf9c5392 h1:xYJJ3S178yv++9zXV/hnr29plCAGO9vAFG9dorqaFQc=
-golang.org/x/crypto v0.0.0-20201124201722-c8d3bf9c5392/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
+golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad h1:DN0cp81fZ3njFcrLCytUHRSUkqBjfTo4Tx9RJTWs0EY=
+golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
@@ -382,10 +382,12 @@ golang.org/x/net v0.0.0-20200822124328-c89045814202/go.mod h1:/O7V0waA8r7cgGh81R
 golang.org/x/net v0.0.0-20201010224723-4f7140c49acb/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20201031054903-ff519b6c9102/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.0.0-20201110031124-69a78807bb2b h1:uwuIcX0g4Yl1NC5XAz37xsr2lTtcqevgzYNVt49waME=
 golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.0.0-20201216054612-986b41b23924 h1:QsnDpLLOKwHBBDa8nDws4DYNc/ryVW2vCpxCs09d4PY=
 golang.org/x/net v0.0.0-20201216054612-986b41b23924/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20201224014010-6772e930b67b/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20210119194325-5f4716e94777/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20210220033124-5f55cee0dc0d h1:1aflnvSoWWLI2k/dMUAl5lvU1YO4Mb4hz0gh+1rjcxU=
+golang.org/x/net v0.0.0-20210220033124-5f55cee0dc0d/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -438,9 +440,15 @@ golang.org/x/sys v0.0.0-20201107080550-4d91cf3a1aaf/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20201112073958-5cba982894dd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201118182958-a01c418693c7/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20201202213521-69691e467435/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20201218084310-7d0127a74742 h1:+CBz4km/0KPU3RGTwARGh/noP3bEwtHcq+0YcBQM2JQ=
 golang.org/x/sys v0.0.0-20201218084310-7d0127a74742/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210105210732-16f7687f5001/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210110051926-789bb1bd4061/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210123111255-9b0068b26619/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210216163648-f7da38b97c65/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210216224549-f992740a1bac/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210220050731-9a76102bfb43 h1:SgQ6LNaYJU0JIuEHv9+s6EbhSCwYeAf5Yvj6lpYlqAE=
+golang.org/x/sys v0.0.0-20210220050731-9a76102bfb43/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 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 v0.0.0-20201207232118-ee85cb95a76b h1:a0ErnNnPKmhDyIXQvdZr+Lq8dc8xpMeqkF8y5PgQU4Q=
@@ -538,7 +546,6 @@ gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWD
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.2.7 h1:VUgggvou5XRW9mHwD/yXxIYSMtY0zoKQf/v226p2nyo=
 gopkg.in/yaml.v2 v2.2.7/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
@@ -552,10 +559,12 @@ honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWh
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
 honnef.co/go/tools v0.1.0 h1:AWNL1W1i7f0wNZ8VwOKNJ0sliKvOF/adn0EHenfUh+c=
 honnef.co/go/tools v0.1.0/go.mod h1:XtegFAyX/PfluP4921rXU5IkjkqBCDnUq4W8VCIoKvM=
-inet.af/netaddr v0.0.0-20201228234250-33d0a924ebbf h1:0eHZ8v6j5wIiOVyoYPd70ueZ/RPEQtRlzi60uneDbRU=
-inet.af/netaddr v0.0.0-20201228234250-33d0a924ebbf/go.mod h1:9NdhtHLglxJliAZB6aC5ws3mfnUArdAzHG/iJq7cB/o=
 inet.af/netaddr v0.0.0-20210105212526-648fbc18a69d h1:6f0242aW/6x2enQBOSKgDS8KQNw6Tp7IVR8eG3x0Jc8=
 inet.af/netaddr v0.0.0-20210105212526-648fbc18a69d/go.mod h1:jPZo7Jy4nke2cCgISa4fKJKa5T7+EO8k5fWwWghzneg=
+inet.af/netaddr v0.0.0-20210222205655-a1ec2b7b8c44 h1:p7fX77zWzZMuNdJUhniBsmN1OvFOrW9SOtvgnzqUZX4=
+inet.af/netaddr v0.0.0-20210222205655-a1ec2b7b8c44/go.mod h1:I2i9ONCXRZDnG1+7O8fSuYzjcPxHQXrIfzD/IkR87x4=
+inet.af/peercred v0.0.0-20210216231719-993aa01eacaa h1:6qseJO2iNDHl+MLL2BkO5oURJR4A9pLmRz11Yf7KdGM=
+inet.af/peercred v0.0.0-20210216231719-993aa01eacaa/go.mod h1:VZeNdG7cRIUqKl9DWoFX86AHyfYwdb4RextAw1CAEO4=
 k8s.io/api v0.16.13/go.mod h1:QWu8UWSTiuQZMMeYjwLs6ILu5O74qKSJ0c+4vrchDxs=
 k8s.io/apimachinery v0.16.13/go.mod h1:4HMHS3mDHtVttspuuhrJ1GGr/0S9B6iWYWZ57KnnZqQ=
 k8s.io/apimachinery v0.16.14-rc.0/go.mod h1:4HMHS3mDHtVttspuuhrJ1GGr/0S9B6iWYWZ57KnnZqQ=

health/health.go

@@ -0,0 +1,71 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package health is a registry for other packages to report & check
+// overall health status of the node.
+package health
+
+import (
+	"sync"
+)
+
+var (
+	mu       sync.Mutex
+	m        = map[string]error{}                     // error key => err (or nil for no error)
+	watchers = map[*watchHandle]func(string, error){} // opt func to run if error state changes
+)
+
+type watchHandle byte
+
+// RegisterWatcher adds a function that will be called if an
+// error changes state either to unhealthy or from unhealthy. It is
+// not called on transition from unknown to healthy. It must be non-nil
+// and is run in its own goroutine. The returned func unregisters it.
+func RegisterWatcher(cb func(errKey string, err error)) (unregister func()) {
+	mu.Lock()
+	defer mu.Unlock()
+	handle := new(watchHandle)
+	watchers[handle] = cb
+	return func() {
+		mu.Lock()
+		defer mu.Unlock()
+		delete(watchers, handle)
+	}
+}
+
+// SetRouter sets the state of the wgengine/router.Router.
+func SetRouterHealth(err error) { set("router", err) }
+
+// RouterHealth returns the wgengine/router.Router error state.
+func RouterHealth() error { return get("router") }
+
+func get(key string) error {
+	mu.Lock()
+	defer mu.Unlock()
+	return m[key]
+}
+
+func set(key string, err error) {
+	mu.Lock()
+	defer mu.Unlock()
+	old, ok := m[key]
+	if !ok && err == nil {
+		// Initial happy path.
+		m[key] = nil
+		return
+	}
+	if ok && (old == nil) == (err == nil) {
+		// No change in overall error status (nil-vs-not), so
+		// don't run callbacks, but exact error might've
+		// changed, so note it.
+		if err != nil {
+			m[key] = err
+		}
+		return
+	}
+	m[key] = err
+	for _, cb := range watchers {
+		go cb(key, err)
+	}
+}

internal/deepprint/deepprint_test.go

@@ -8,10 +8,10 @@ import (
 	"bytes"
 	"testing"
 
-	"github.com/tailscale/wireguard-go/wgcfg"
 	"inet.af/netaddr"
 	"tailscale.com/wgengine/router"
 	"tailscale.com/wgengine/router/dns"
+	"tailscale.com/wgengine/wgcfg"
 )
 
 func TestDeepPrint(t *testing.T) {

ipn/backend.go

@@ -9,12 +9,11 @@ import (
 	"time"
 
 	"golang.org/x/oauth2"
-	"tailscale.com/control/controlclient"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/empty"
+	"tailscale.com/types/netmap"
 	"tailscale.com/types/structs"
-	"tailscale.com/wgengine"
 )
 
 type State int
@@ -46,10 +45,10 @@ func (s State) String() string {
 
 // EngineStatus contains WireGuard engine stats.
 type EngineStatus struct {
-	RBytes, WBytes wgengine.ByteCount
+	RBytes, WBytes int64
 	NumLive        int
 	LiveDERPs      int // number of active DERP connections
-	LivePeers      map[tailcfg.NodeKey]wgengine.PeerStatus
+	LivePeers      map[tailcfg.NodeKey]ipnstate.PeerStatusLite
 }
 
 // Notify is a communication from a backend (e.g. tailscaled) to a frontend
@@ -59,16 +58,16 @@ type EngineStatus struct {
 // They are JSON-encoded on the wire, despite the lack of struct tags.
 type Notify struct {
 	_             structs.Incomparable
-	Version       string                    // version number of IPN backend
-	ErrMessage    *string                   // critical error message, if any; for InUseOtherUser, the details
-	LoginFinished *empty.Message            // event: non-nil when login process succeeded
-	State         *State                    // current IPN state has changed
-	Prefs         *Prefs                    // preferences were changed
-	NetMap        *controlclient.NetworkMap // new netmap received
-	Engine        *EngineStatus             // wireguard engine stats
-	Status        *ipnstate.Status          // full status
-	BrowseToURL   *string                   // UI should open a browser right now
-	BackendLogID  *string                   // public logtail id used by backend
+	Version       string             // version number of IPN backend
+	ErrMessage    *string            // critical error message, if any; for InUseOtherUser, the details
+	LoginFinished *empty.Message     // event: non-nil when login process succeeded
+	State         *State             // current IPN state has changed
+	Prefs         *Prefs             // preferences were changed
+	NetMap        *netmap.NetworkMap // new netmap received
+	Engine        *EngineStatus      // wireguard engine stats
+	Status        *ipnstate.Status   // full status
+	BrowseToURL   *string            // UI should open a browser right now
+	BackendLogID  *string            // public logtail id used by backend
 	PingResult    *ipnstate.PingResult
 
 	// LocalTCPPort, if non-nil, informs the UI frontend which

ipn/fake_test.go

@@ -9,8 +9,8 @@ import (
 	"time"
 
 	"golang.org/x/oauth2"
-	"tailscale.com/control/controlclient"
 	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/types/netmap"
 )
 
 type FakeBackend struct {
@@ -54,7 +54,7 @@ func (b *FakeBackend) login() {
 	b.newState(NeedsMachineAuth)
 	b.newState(Stopped)
 	// TODO(apenwarr): Fill in a more interesting netmap here.
-	b.notify(Notify{NetMap: &controlclient.NetworkMap{}})
+	b.notify(Notify{NetMap: &netmap.NetworkMap{}})
 	b.newState(Starting)
 	// TODO(apenwarr): Fill in a more interesting status.
 	b.notify(Notify{Engine: &EngineStatus{}})
@@ -92,7 +92,7 @@ func (b *FakeBackend) RequestStatus() {
 }
 
 func (b *FakeBackend) FakeExpireAfter(x time.Duration) {
-	b.notify(Notify{NetMap: &controlclient.NetworkMap{}})
+	b.notify(Notify{NetMap: &netmap.NetworkMap{}})
 }
 
 func (b *FakeBackend) Ping(ip string) {

ipn/handle.go

@@ -10,8 +10,8 @@ import (
 
 	"golang.org/x/oauth2"
 	"inet.af/netaddr"
-	"tailscale.com/control/controlclient"
 	"tailscale.com/types/logger"
+	"tailscale.com/types/netmap"
 )
 
 type Handle struct {
@@ -22,7 +22,7 @@ type Handle struct {
 
 	// Mutex protects everything below
 	mu                sync.Mutex
-	netmapCache       *controlclient.NetworkMap
+	netmapCache       *netmap.NetworkMap
 	engineStatusCache EngineStatus
 	stateCache        State
 	prefsCache        *Prefs
@@ -129,7 +129,7 @@ func (h *Handle) LocalAddrs() []netaddr.IPPrefix {
 	return []netaddr.IPPrefix{}
 }
 
-func (h *Handle) NetMap() *controlclient.NetworkMap {
+func (h *Handle) NetMap() *netmap.NetworkMap {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 

ipn/ipnlocal/local.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package ipn
+package ipnlocal
 
 import (
 	"bytes"
@@ -15,11 +15,11 @@ import (
 	"sync"
 	"time"
 
-	"github.com/tailscale/wireguard-go/wgcfg"
 	"golang.org/x/oauth2"
 	"inet.af/netaddr"
 	"tailscale.com/control/controlclient"
 	"tailscale.com/internal/deepprint"
+	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/ipn/policy"
 	"tailscale.com/net/interfaces"
@@ -29,6 +29,8 @@ import (
 	"tailscale.com/types/empty"
 	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
+	"tailscale.com/types/netmap"
+	"tailscale.com/types/persist"
 	"tailscale.com/types/wgkey"
 	"tailscale.com/util/systemd"
 	"tailscale.com/version"
@@ -37,6 +39,8 @@ import (
 	"tailscale.com/wgengine/router"
 	"tailscale.com/wgengine/router/dns"
 	"tailscale.com/wgengine/tsdns"
+	"tailscale.com/wgengine/wgcfg"
+	"tailscale.com/wgengine/wgcfg/nmcfg"
 )
 
 var controlDebugFlags = getControlDebugFlags()
@@ -60,38 +64,40 @@ func getControlDebugFlags() []string {
 // state machine generates events back out to zero or more components.
 type LocalBackend struct {
 	// Elements that are thread-safe or constant after construction.
-	ctx             context.Context    // canceled by Close
-	ctxCancel       context.CancelFunc // cancels ctx
-	logf            logger.Logf        // general logging
-	keyLogf         logger.Logf        // for printing list of peers on change
-	statsLogf       logger.Logf        // for printing peers stats on change
-	e               wgengine.Engine
-	store           StateStore
-	backendLogID    string
-	portpoll        *portlist.Poller // may be nil
-	portpollOnce    sync.Once        // guards starting readPoller
-	gotPortPollRes  chan struct{}    // closed upon first readPoller result
-	serverURL       string           // tailcontrol URL
-	newDecompressor func() (controlclient.Decompressor, error)
+	ctx               context.Context    // canceled by Close
+	ctxCancel         context.CancelFunc // cancels ctx
+	logf              logger.Logf        // general logging
+	keyLogf           logger.Logf        // for printing list of peers on change
+	statsLogf         logger.Logf        // for printing peers stats on change
+	e                 wgengine.Engine
+	store             ipn.StateStore
+	backendLogID      string
+	unregisterLinkMon func()
+	portpoll          *portlist.Poller // may be nil
+	portpollOnce      sync.Once        // guards starting readPoller
+	gotPortPollRes    chan struct{}    // closed upon first readPoller result
+	serverURL         string           // tailcontrol URL
+	newDecompressor   func() (controlclient.Decompressor, error)
 
 	filterHash string
 
 	// The mutex protects the following elements.
 	mu             sync.Mutex
-	notify         func(Notify)
+	notify         func(ipn.Notify)
 	c              *controlclient.Client
-	stateKey       StateKey // computed in part from user-provided value
-	userID         string   // current controlling user ID (for Windows, primarily)
-	prefs          *Prefs
+	stateKey       ipn.StateKey // computed in part from user-provided value
+	userID         string       // current controlling user ID (for Windows, primarily)
+	prefs          *ipn.Prefs
 	inServerMode   bool
 	machinePrivKey wgkey.Private
-	state          State
+	state          ipn.State
 	// hostinfo is mutated in-place while mu is held.
 	hostinfo *tailcfg.Hostinfo
 	// netMap is not mutated in-place once set.
-	netMap       *controlclient.NetworkMap
+	netMap       *netmap.NetworkMap
+	nodeByAddr   map[netaddr.IP]*tailcfg.Node
 	activeLogin  string // last logged LoginName from netMap
-	engineStatus EngineStatus
+	engineStatus ipn.EngineStatus
 	endpoints    []string
 	blocked      bool
 	authURL      string
@@ -106,7 +112,7 @@ type LocalBackend struct {
 
 // NewLocalBackend returns a new LocalBackend that is ready to run,
 // but is not actually running.
-func NewLocalBackend(logf logger.Logf, logid string, store StateStore, e wgengine.Engine) (*LocalBackend, error) {
+func NewLocalBackend(logf logger.Logf, logid string, store ipn.StateStore, e wgengine.Engine) (*LocalBackend, error) {
 	if e == nil {
 		panic("ipn.NewLocalBackend: wgengine must not be nil")
 	}
@@ -129,18 +135,23 @@ func NewLocalBackend(logf logger.Logf, logid string, store StateStore, e wgengin
 		e:              e,
 		store:          store,
 		backendLogID:   logid,
-		state:          NoState,
+		state:          ipn.NoState,
 		portpoll:       portpoll,
 		gotPortPollRes: make(chan struct{}),
 	}
-	e.SetLinkChangeCallback(b.linkChange)
 	b.statusChanged = sync.NewCond(&b.statusLock)
 
+	linkMon := e.GetLinkMonitor()
+	// Call our linkChange code once with the current state, and
+	// then also whenever it changes:
+	b.linkChange(false, linkMon.InterfaceState())
+	b.unregisterLinkMon = linkMon.RegisterChangeCallback(b.linkChange)
+
 	return b, nil
 }
 
-// linkChange is called (in a new goroutine) by wgengine when its link monitor
-// detects a network change.
+// linkChange is our link monitor callback, called whenever the network changes.
+// major is whether ifst is different than earlier.
 func (b *LocalBackend) linkChange(major bool, ifst *interfaces.State) {
 	b.mu.Lock()
 	defer b.mu.Unlock()
@@ -150,7 +161,7 @@ func (b *LocalBackend) linkChange(major bool, ifst *interfaces.State) {
 
 	networkUp := ifst.AnyInterfaceUp()
 	if b.c != nil {
-		go b.c.SetPaused(b.state == Stopped || !networkUp)
+		go b.c.SetPaused(b.state == ipn.Stopped || !networkUp)
 	}
 
 	// If the PAC-ness of the network changed, reconfig wireguard+route to
@@ -158,12 +169,16 @@ func (b *LocalBackend) linkChange(major bool, ifst *interfaces.State) {
 	if hadPAC != ifst.HasPAC() {
 		b.logf("linkChange: in state %v; PAC changed from %v->%v", b.state, hadPAC, ifst.HasPAC())
 		switch b.state {
-		case NoState, Stopped:
+		case ipn.NoState, ipn.Stopped:
 			// Do nothing.
 		default:
 			go b.authReconfig()
 		}
 	}
+
+	// If the local network configuration has changed, our filter may
+	// need updating to tweak default routes.
+	b.updateFilter(b.netMap, b.prefs)
 }
 
 // Shutdown halts the backend and all its sub-components. The backend
@@ -173,6 +188,7 @@ func (b *LocalBackend) Shutdown() {
 	cli := b.c
 	b.mu.Unlock()
 
+	b.unregisterLinkMon()
 	if cli != nil {
 		cli.Shutdown()
 	}
@@ -231,10 +247,26 @@ func (b *LocalBackend) UpdateStatus(sb *ipnstate.StatusBuilder) {
 				Created:      p.Created,
 				LastSeen:     lastSeen,
 				ShareeNode:   p.Hostinfo.ShareeNode,
+				ExitNode:     p.StableID != "" && p.StableID == b.prefs.ExitNodeID,
 			})
 		}
 	}
+}
 
+// WhoIs reports the node and user who owns the node with the given IP.
+// If ok == true, n and u are valid.
+func (b *LocalBackend) WhoIs(ip netaddr.IP) (n *tailcfg.Node, u tailcfg.UserProfile, ok bool) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	n, ok = b.nodeByAddr[ip]
+	if !ok {
+		return nil, u, false
+	}
+	u, ok = b.netMap.UserProfiles[n.User]
+	if !ok {
+		return nil, u, false
+	}
+	return n, u, true
 }
 
 // SetDecompressor sets a decompression function, which must be a zstd
@@ -264,7 +296,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 		// Auth completed, unblock the engine
 		b.blockEngineUpdates(false)
 		b.authReconfig()
-		b.send(Notify{LoginFinished: &empty.Message{}})
+		b.send(ipn.Notify{LoginFinished: &empty.Message{}})
 	}
 
 	prefsChanged := false
@@ -289,13 +321,15 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 		prefsChanged = true
 	}
 	if st.NetMap != nil {
+		if b.findExitNodeIDLocked(st.NetMap) {
+			prefsChanged = true
+		}
 		b.setNetMapLocked(st.NetMap)
-
 	}
 	if st.URL != "" {
 		b.authURL = st.URL
 	}
-	if b.state == NeedsLogin {
+	if b.state == ipn.NeedsLogin {
 		if !b.prefs.WantRunning {
 			prefsChanged = true
 		}
@@ -315,7 +349,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 				b.logf("Failed to save new controlclient state: %v", err)
 			}
 		}
-		b.send(Notify{Prefs: prefs})
+		b.send(ipn.Notify{Prefs: prefs})
 	}
 	if st.NetMap != nil {
 		if netMap != nil {
@@ -334,7 +368,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 		}
 		b.e.SetDERPMap(st.NetMap.DERPMap)
 
-		b.send(Notify{NetMap: st.NetMap})
+		b.send(ipn.Notify{NetMap: st.NetMap})
 	}
 	if st.URL != "" {
 		b.logf("Received auth URL: %.20v...", st.URL)
@@ -348,6 +382,37 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 	b.authReconfig()
 }
 
+// findExitNodeIDLocked updates b.prefs to reference an exit node by ID,
+// rather than by IP. It returns whether prefs was mutated.
+func (b *LocalBackend) findExitNodeIDLocked(nm *netmap.NetworkMap) (prefsChanged bool) {
+	// If we have a desired IP on file, try to find the corresponding
+	// node.
+	if b.prefs.ExitNodeIP.IsZero() {
+		return false
+	}
+
+	// IP takes precedence over ID, so if both are set, clear ID.
+	if b.prefs.ExitNodeID != "" {
+		b.prefs.ExitNodeID = ""
+		prefsChanged = true
+	}
+
+	for _, peer := range nm.Peers {
+		for _, addr := range peer.Addresses {
+			if !addr.IsSingleIP() || addr.IP != b.prefs.ExitNodeIP {
+				continue
+			}
+			// Found the node being referenced, upgrade prefs to
+			// reference it directly for next time.
+			b.prefs.ExitNodeID = peer.StableID
+			b.prefs.ExitNodeIP = netaddr.IP{}
+			return true
+		}
+	}
+
+	return false
+}
+
 // setWgengineStatus is the callback by the wireguard engine whenever it posts a new status.
 // This updates the endpoints both in the backend and in the control client.
 func (b *LocalBackend) setWgengineStatus(s *wgengine.Status, err error) {
@@ -376,7 +441,7 @@ func (b *LocalBackend) setWgengineStatus(s *wgengine.Status, err error) {
 	b.statusChanged.Broadcast()
 	b.statusLock.Unlock()
 
-	b.send(Notify{Engine: &es})
+	b.send(ipn.Notify{Engine: &es})
 }
 
 // Start applies the configuration specified in opts, and starts the
@@ -389,7 +454,7 @@ func (b *LocalBackend) setWgengineStatus(s *wgengine.Status, err error) {
 // guarantee that switching from one user's state to another is
 // actually a supported operation (it should be, but it's very unclear
 // from the following whether or not that is a safe transition).
-func (b *LocalBackend) Start(opts Options) error {
+func (b *LocalBackend) Start(opts ipn.Options) error {
 	if opts.Prefs == nil && opts.StateKey == "" {
 		return errors.New("no state key or prefs provided")
 	}
@@ -422,7 +487,7 @@ func (b *LocalBackend) Start(opts Options) error {
 		hostinfo.NetInfo = b.hostinfo.NetInfo
 	}
 	b.hostinfo = hostinfo
-	b.state = NoState
+	b.state = ipn.NoState
 
 	if err := b.loadStateLocked(opts.StateKey, opts.Prefs, opts.LegacyConfigPath); err != nil {
 		b.mu.Unlock()
@@ -440,7 +505,7 @@ func (b *LocalBackend) Start(opts Options) error {
 
 	b.notify = opts.Notify
 	b.setNetMapLocked(nil)
-	persist := b.prefs.Persist
+	persistv := b.prefs.Persist
 	machinePrivKey := b.machinePrivKey
 	b.mu.Unlock()
 
@@ -473,14 +538,14 @@ func (b *LocalBackend) Start(opts Options) error {
 	}
 
 	var err error
-	if persist == nil {
+	if persistv == nil {
 		// let controlclient initialize it
-		persist = &controlclient.Persist{}
+		persistv = &persist.Persist{}
 	}
 	cli, err := controlclient.New(controlclient.Options{
 		MachinePrivateKey: machinePrivKey,
 		Logf:              logger.WithPrefix(b.logf, "control: "),
-		Persist:           *persist,
+		Persist:           *persistv,
 		ServerURL:         b.serverURL,
 		AuthKey:           opts.AuthKey,
 		Hostinfo:          hostinfo,
@@ -519,8 +584,8 @@ func (b *LocalBackend) Start(opts Options) error {
 
 	blid := b.backendLogID
 	b.logf("Backend: logs: be:%v fe:%v", blid, opts.FrontendLogID)
-	b.send(Notify{BackendLogID: &blid})
-	b.send(Notify{Prefs: prefs})
+	b.send(ipn.Notify{BackendLogID: &blid})
+	b.send(ipn.Notify{Prefs: prefs})
 
 	cli.Login(nil, controlclient.LoginDefault)
 	return nil
@@ -528,7 +593,7 @@ func (b *LocalBackend) Start(opts Options) error {
 
 // updateFilter updates the packet filter in wgengine based on the
 // given netMap and user preferences.
-func (b *LocalBackend) updateFilter(netMap *controlclient.NetworkMap, prefs *Prefs) {
+func (b *LocalBackend) updateFilter(netMap *netmap.NetworkMap, prefs *ipn.Prefs) {
 	// NOTE(danderson): keep change detection as the first thing in
 	// this function. Don't try to optimize by returning early, more
 	// likely than not you'll just end up breaking the change
@@ -538,18 +603,39 @@ func (b *LocalBackend) updateFilter(netMap *controlclient.NetworkMap, prefs *Pre
 		haveNetmap   = netMap != nil
 		addrs        []netaddr.IPPrefix
 		packetFilter []filter.Match
-		advRoutes    []netaddr.IPPrefix
+		localNetsB   netaddr.IPSetBuilder
 		shieldsUp    = prefs == nil || prefs.ShieldsUp // Be conservative when not ready
 	)
 	if haveNetmap {
 		addrs = netMap.Addresses
+		for _, p := range addrs {
+			localNetsB.AddPrefix(p)
+		}
 		packetFilter = netMap.PacketFilter
 	}
 	if prefs != nil {
-		advRoutes = prefs.AdvertiseRoutes
+		for _, r := range prefs.AdvertiseRoutes {
+			if r.Bits == 0 {
+				// When offering a default route to the world, we
+				// filter out locally reachable LANs, so that the
+				// default route effectively appears to be a "guest
+				// wifi": you get internet access, but to additionally
+				// get LAN access the LAN(s) need to be offered
+				// explicitly as well.
+				s, err := shrinkDefaultRoute(r)
+				if err != nil {
+					b.logf("computing default route filter: %v", err)
+					continue
+				}
+				localNetsB.AddSet(s)
+			} else {
+				localNetsB.AddPrefix(r)
+			}
+		}
 	}
+	localNets := localNetsB.IPSet()
 
-	changed := deepprint.UpdateHash(&b.filterHash, haveNetmap, addrs, packetFilter, advRoutes, shieldsUp)
+	changed := deepprint.UpdateHash(&b.filterHash, haveNetmap, addrs, packetFilter, localNets.Ranges(), shieldsUp)
 	if !changed {
 		return
 	}
@@ -560,17 +646,52 @@ func (b *LocalBackend) updateFilter(netMap *controlclient.NetworkMap, prefs *Pre
 		return
 	}
 
-	localNets := unmapIPPrefixes(netMap.Addresses, advRoutes)
-
+	oldFilter := b.e.GetFilter()
 	if shieldsUp {
 		b.logf("netmap packet filter: (shields up)")
-		b.e.SetFilter(filter.NewShieldsUpFilter(b.logf))
+		b.e.SetFilter(filter.NewShieldsUpFilter(localNets, oldFilter, b.logf))
 	} else {
 		b.logf("netmap packet filter: %v", packetFilter)
-		b.e.SetFilter(filter.New(packetFilter, localNets, b.e.GetFilter(), b.logf))
+		b.e.SetFilter(filter.New(packetFilter, localNets, oldFilter, b.logf))
 	}
 }
 
+var removeFromDefaultRoute = []netaddr.IPPrefix{
+	// RFC1918 LAN ranges
+	netaddr.MustParseIPPrefix("192.168.0.0/16"),
+	netaddr.MustParseIPPrefix("172.16.0.0/12"),
+	netaddr.MustParseIPPrefix("10.0.0.0/8"),
+	// Tailscale IPv4 range
+	tsaddr.CGNATRange(),
+	// IPv6 Link-local addresses
+	netaddr.MustParseIPPrefix("fe80::/10"),
+	// Tailscale IPv6 range
+	tsaddr.TailscaleULARange(),
+}
+
+// shrinkDefaultRoute returns an IPSet representing the IPs in route,
+// minus those in removeFromDefaultRoute and local interface subnets.
+func shrinkDefaultRoute(route netaddr.IPPrefix) (*netaddr.IPSet, error) {
+	var b netaddr.IPSetBuilder
+	b.AddPrefix(route)
+	err := interfaces.ForeachInterfaceAddress(func(_ interfaces.Interface, pfx netaddr.IPPrefix) {
+		if tsaddr.IsTailscaleIP(pfx.IP) {
+			return
+		}
+		if pfx.IsSingleIP() {
+			return
+		}
+		b.RemovePrefix(pfx)
+	})
+	if err != nil {
+		return nil, err
+	}
+	for _, pfx := range removeFromDefaultRoute {
+		b.RemovePrefix(pfx)
+	}
+	return b.IPSet(), nil
+}
+
 // dnsCIDRsEqual determines whether two CIDR lists are equal
 // for DNS map construction purposes (that is, only the first entry counts).
 func dnsCIDRsEqual(newAddr, oldAddr []netaddr.IPPrefix) bool {
@@ -586,7 +707,7 @@ func dnsCIDRsEqual(newAddr, oldAddr []netaddr.IPPrefix) bool {
 // dnsMapsEqual determines whether the new and the old network map
 // induce the same DNS map. It does so without allocating memory,
 // at the expense of giving false negatives if peers are reordered.
-func dnsMapsEqual(new, old *controlclient.NetworkMap) bool {
+func dnsMapsEqual(new, old *netmap.NetworkMap) bool {
 	if (old == nil) != (new == nil) {
 		return false
 	}
@@ -620,7 +741,7 @@ func dnsMapsEqual(new, old *controlclient.NetworkMap) bool {
 
 // updateDNSMap updates the domain map in the DNS resolver in wgengine
 // based on the given netMap and user preferences.
-func (b *LocalBackend) updateDNSMap(netMap *controlclient.NetworkMap) {
+func (b *LocalBackend) updateDNSMap(netMap *netmap.NetworkMap) {
 	if netMap == nil {
 		b.logf("dns map: (not ready)")
 		return
@@ -684,7 +805,7 @@ func (b *LocalBackend) readPoller() {
 
 // send delivers n to the connected frontend. If no frontend is
 // connected, the notification is dropped without being delivered.
-func (b *LocalBackend) send(n Notify) {
+func (b *LocalBackend) send(n ipn.Notify) {
 	b.mu.Lock()
 	notify := b.notify
 	b.mu.Unlock()
@@ -710,9 +831,9 @@ func (b *LocalBackend) popBrowserAuthNow() {
 
 	b.blockEngineUpdates(true)
 	b.stopEngineAndWait()
-	b.send(Notify{BrowseToURL: &url})
-	if b.State() == Running {
-		b.enterState(Starting)
+	b.send(ipn.Notify{BrowseToURL: &url})
+	if b.State() == ipn.Running {
+		b.enterState(ipn.Starting)
 	}
 }
 
@@ -743,21 +864,21 @@ func (b *LocalBackend) initMachineKeyLocked() (err error) {
 		legacyMachineKey = b.prefs.Persist.LegacyFrontendPrivateMachineKey
 	}
 
-	keyText, err := b.store.ReadState(MachineKeyStateKey)
+	keyText, err := b.store.ReadState(ipn.MachineKeyStateKey)
 	if err == nil {
 		if err := b.machinePrivKey.UnmarshalText(keyText); err != nil {
-			return fmt.Errorf("invalid key in %s key of %v: %w", MachineKeyStateKey, b.store, err)
+			return fmt.Errorf("invalid key in %s key of %v: %w", ipn.MachineKeyStateKey, b.store, err)
 		}
 		if b.machinePrivKey.IsZero() {
-			return fmt.Errorf("invalid zero key stored in %v key of %v", MachineKeyStateKey, b.store)
+			return fmt.Errorf("invalid zero key stored in %v key of %v", ipn.MachineKeyStateKey, b.store)
 		}
 		if !legacyMachineKey.IsZero() && !bytes.Equal(legacyMachineKey[:], b.machinePrivKey[:]) {
 			b.logf("frontend-provided legacy machine key ignored; used value from server state")
 		}
 		return nil
 	}
-	if err != ErrStateNotExist {
-		return fmt.Errorf("error reading %v key of %v: %w", MachineKeyStateKey, b.store, err)
+	if err != ipn.ErrStateNotExist {
+		return fmt.Errorf("error reading %v key of %v: %w", ipn.MachineKeyStateKey, b.store, err)
 	}
 
 	// If we didn't find one already on disk and the prefs already
@@ -780,7 +901,7 @@ func (b *LocalBackend) initMachineKeyLocked() (err error) {
 	}
 
 	keyText, _ = b.machinePrivKey.MarshalText()
-	if err := b.store.WriteState(MachineKeyStateKey, keyText); err != nil {
+	if err := b.store.WriteState(ipn.MachineKeyStateKey, keyText); err != nil {
 		b.logf("error writing machine key to store: %v", err)
 		return err
 	}
@@ -793,14 +914,14 @@ func (b *LocalBackend) initMachineKeyLocked() (err error) {
 // user and prefs. If userID is blank or prefs is blank, no work is done.
 //
 // b.mu may either be held or not.
-func (b *LocalBackend) writeServerModeStartState(userID string, prefs *Prefs) {
+func (b *LocalBackend) writeServerModeStartState(userID string, prefs *ipn.Prefs) {
 	if userID == "" || prefs == nil {
 		return
 	}
 
 	if prefs.ForceDaemon {
-		stateKey := StateKey("user-" + userID)
-		if err := b.store.WriteState(ServerModeStartKey, []byte(stateKey)); err != nil {
+		stateKey := ipn.StateKey("user-" + userID)
+		if err := b.store.WriteState(ipn.ServerModeStartKey, []byte(stateKey)); err != nil {
 			b.logf("WriteState error: %v", err)
 		}
 		// It's important we do this here too, even if it looks
@@ -812,7 +933,7 @@ func (b *LocalBackend) writeServerModeStartState(userID string, prefs *Prefs) {
 			b.logf("WriteState error: %v", err)
 		}
 	} else {
-		if err := b.store.WriteState(ServerModeStartKey, nil); err != nil {
+		if err := b.store.WriteState(ipn.ServerModeStartKey, nil); err != nil {
 			b.logf("WriteState error: %v", err)
 		}
 	}
@@ -821,7 +942,7 @@ func (b *LocalBackend) writeServerModeStartState(userID string, prefs *Prefs) {
 // loadStateLocked sets b.prefs and b.stateKey based on a complex
 // combination of key, prefs, and legacyPath. b.mu must be held when
 // calling.
-func (b *LocalBackend) loadStateLocked(key StateKey, prefs *Prefs, legacyPath string) (err error) {
+func (b *LocalBackend) loadStateLocked(key ipn.StateKey, prefs *ipn.Prefs, legacyPath string) (err error) {
 	if prefs == nil && key == "" {
 		panic("state key and prefs are both unset")
 	}
@@ -863,19 +984,19 @@ func (b *LocalBackend) loadStateLocked(key StateKey, prefs *Prefs, legacyPath st
 	b.logf("using backend prefs")
 	bs, err := b.store.ReadState(key)
 	if err != nil {
-		if errors.Is(err, ErrStateNotExist) {
+		if errors.Is(err, ipn.ErrStateNotExist) {
 			if legacyPath != "" {
-				b.prefs, err = LoadPrefs(legacyPath)
+				b.prefs, err = ipn.LoadPrefs(legacyPath)
 				if err != nil {
 					if !errors.Is(err, os.ErrNotExist) {
 						b.logf("failed to load legacy prefs: %v", err)
 					}
-					b.prefs = NewPrefs()
+					b.prefs = ipn.NewPrefs()
 				} else {
 					b.logf("imported prefs from relaynode for %q: %v", key, b.prefs.Pretty())
 				}
 			} else {
-				b.prefs = NewPrefs()
+				b.prefs = ipn.NewPrefs()
 				b.logf("created empty state for %q: %s", key, b.prefs.Pretty())
 			}
 			if err := b.initMachineKeyLocked(); err != nil {
@@ -885,7 +1006,7 @@ func (b *LocalBackend) loadStateLocked(key StateKey, prefs *Prefs, legacyPath st
 		}
 		return fmt.Errorf("store.ReadState(%q): %v", key, err)
 	}
-	b.prefs, err = PrefsFromBytes(bs, false)
+	b.prefs, err = ipn.PrefsFromBytes(bs, false)
 	if err != nil {
 		return fmt.Errorf("PrefsFromBytes: %v", err)
 	}
@@ -897,7 +1018,7 @@ func (b *LocalBackend) loadStateLocked(key StateKey, prefs *Prefs, legacyPath st
 }
 
 // State returns the backend state machine's current state.
-func (b *LocalBackend) State() State {
+func (b *LocalBackend) State() ipn.State {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
@@ -913,7 +1034,7 @@ func (b *LocalBackend) InServerMode() bool {
 // getEngineStatus returns a copy of b.engineStatus.
 //
 // TODO(bradfitz): remove this and use Status() throughout.
-func (b *LocalBackend) getEngineStatus() EngineStatus {
+func (b *LocalBackend) getEngineStatus() ipn.EngineStatus {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
@@ -969,7 +1090,7 @@ func (b *LocalBackend) FakeExpireAfter(x time.Duration) {
 		mapCopy.Expiry = time.Now().Add(x)
 	}
 	b.setNetMapLocked(&mapCopy)
-	b.send(Notify{NetMap: b.netMap})
+	b.send(ipn.Notify{NetMap: b.netMap})
 }
 
 func (b *LocalBackend) Ping(ipStr string) {
@@ -979,7 +1100,7 @@ func (b *LocalBackend) Ping(ipStr string) {
 		return
 	}
 	b.e.Ping(ip, func(pr *ipnstate.PingResult) {
-		b.send(Notify{PingResult: pr})
+		b.send(ipn.Notify{PingResult: pr})
 	})
 }
 
@@ -988,11 +1109,11 @@ func (b *LocalBackend) Ping(ipStr string) {
 // b.mu must be held; mostly because the caller is about to anyway, and doing so
 // gives us slightly better guarantees about the two peers stats lines not
 // being intermixed if there are concurrent calls to our caller.
-func (b *LocalBackend) parseWgStatusLocked(s *wgengine.Status) (ret EngineStatus) {
+func (b *LocalBackend) parseWgStatusLocked(s *wgengine.Status) (ret ipn.EngineStatus) {
 	var peerStats, peerKeys strings.Builder
 
 	ret.LiveDERPs = s.DERPs
-	ret.LivePeers = map[tailcfg.NodeKey]wgengine.PeerStatus{}
+	ret.LivePeers = map[tailcfg.NodeKey]ipnstate.PeerStatusLite{}
 	for _, p := range s.Peers {
 		if !p.LastHandshake.IsZero() {
 			fmt.Fprintf(&peerStats, "%d/%d ", p.RxBytes, p.TxBytes)
@@ -1048,7 +1169,7 @@ func (b *LocalBackend) SetWantRunning(wantRunning bool) {
 
 // SetPrefs saves new user preferences and propagates them throughout
 // the system. Implements Backend.
-func (b *LocalBackend) SetPrefs(newp *Prefs) {
+func (b *LocalBackend) SetPrefs(newp *ipn.Prefs) {
 	if newp == nil {
 		panic("SetPrefs got nil prefs")
 	}
@@ -1115,7 +1236,7 @@ func (b *LocalBackend) SetPrefs(newp *Prefs) {
 		b.authReconfig()
 	}
 
-	b.send(Notify{Prefs: newp})
+	b.send(ipn.Notify{Prefs: newp})
 }
 
 // doSetHostinfoFilterServices calls SetHostinfo on the controlclient,
@@ -1141,7 +1262,7 @@ func (b *LocalBackend) doSetHostinfoFilterServices(hi *tailcfg.Hostinfo) {
 
 // NetMap returns the latest cached network map received from
 // controlclient, or nil if no network map was received yet.
-func (b *LocalBackend) NetMap() *controlclient.NetworkMap {
+func (b *LocalBackend) NetMap() *netmap.NetworkMap {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 	return b.netMap
@@ -1183,23 +1304,21 @@ func (b *LocalBackend) authReconfig() {
 		return
 	}
 
-	var flags controlclient.WGConfigFlags
+	var flags netmap.WGConfigFlags
 	if uc.RouteAll {
-		flags |= controlclient.AllowDefaultRoute
-		// TODO(apenwarr): Make subnet routes a different pref?
-		flags |= controlclient.AllowSubnetRoutes
+		flags |= netmap.AllowSubnetRoutes
 	}
 	if uc.AllowSingleHosts {
-		flags |= controlclient.AllowSingleHosts
+		flags |= netmap.AllowSingleHosts
 	}
 	if hasPAC && disableSubnetsIfPAC {
-		if flags&controlclient.AllowSubnetRoutes != 0 {
+		if flags&netmap.AllowSubnetRoutes != 0 {
 			b.logf("authReconfig: have PAC; disabling subnet routes")
-			flags &^= controlclient.AllowSubnetRoutes
+			flags &^= netmap.AllowSubnetRoutes
 		}
 	}
 
-	cfg, err := nm.WGCfg(b.logf, flags)
+	cfg, err := nmcfg.WGCfg(nm, b.logf, flags, uc.ExitNodeID)
 	if err != nil {
 		b.logf("wgcfg: %v", err)
 		return
@@ -1231,15 +1350,20 @@ func (b *LocalBackend) authReconfig() {
 
 // magicDNSRootDomains returns the subset of nm.DNS.Domains that are the search domains for MagicDNS.
 // Each entry has a trailing period.
-func magicDNSRootDomains(nm *controlclient.NetworkMap) []string {
+func magicDNSRootDomains(nm *netmap.NetworkMap) []string {
 	if v := nm.MagicDNSSuffix(); v != "" {
 		return []string{strings.Trim(v, ".") + "."}
 	}
 	return nil
 }
 
+var (
+	ipv4Default = netaddr.MustParseIPPrefix("0.0.0.0/0")
+	ipv6Default = netaddr.MustParseIPPrefix("::/0")
+)
+
 // routerConfig produces a router.Config from a wireguard config and IPN prefs.
-func routerConfig(cfg *wgcfg.Config, prefs *Prefs) *router.Config {
+func routerConfig(cfg *wgcfg.Config, prefs *ipn.Prefs) *router.Config {
 	rs := &router.Config{
 		LocalAddrs:       unmapIPPrefixes(cfg.Addresses),
 		SubnetRoutes:     unmapIPPrefixes(prefs.AdvertiseRoutes),
@@ -1251,6 +1375,32 @@ func routerConfig(cfg *wgcfg.Config, prefs *Prefs) *router.Config {
 		rs.Routes = append(rs.Routes, unmapIPPrefixes(peer.AllowedIPs)...)
 	}
 
+	// Sanity check: we expect the control server to program both a v4
+	// and a v6 default route, if default routing is on. Fill in
+	// blackhole routes appropriately if we're missing some. This is
+	// likely to break some functionality, but if the user expressed a
+	// preference for routing remotely, we want to avoid leaking
+	// traffic at the expense of functionality.
+	if prefs.ExitNodeID != "" || !prefs.ExitNodeIP.IsZero() {
+		var default4, default6 bool
+		for _, route := range rs.Routes {
+			if route == ipv4Default {
+				default4 = true
+			} else if route == ipv6Default {
+				default6 = true
+			}
+			if default4 && default6 {
+				break
+			}
+		}
+		if !default4 {
+			rs.Routes = append(rs.Routes, ipv4Default)
+		}
+		if !default6 {
+			rs.Routes = append(rs.Routes, ipv6Default)
+		}
+	}
+
 	rs.Routes = append(rs.Routes, netaddr.IPPrefix{
 		IP:   tsaddr.TailscaleServiceIP(),
 		Bits: 32,
@@ -1268,7 +1418,7 @@ func unmapIPPrefixes(ippsList ...[]netaddr.IPPrefix) (ret []netaddr.IPPrefix) {
 	return ret
 }
 
-func applyPrefsToHostinfo(hi *tailcfg.Hostinfo, prefs *Prefs) {
+func applyPrefsToHostinfo(hi *tailcfg.Hostinfo, prefs *ipn.Prefs) {
 	if h := prefs.Hostname; h != "" {
 		hi.Hostname = h
 	}
@@ -1288,7 +1438,7 @@ func applyPrefsToHostinfo(hi *tailcfg.Hostinfo, prefs *Prefs) {
 // places twiddle IPN internal state without going through here, so
 // really this is more "one of several places in which random things
 // happen".
-func (b *LocalBackend) enterState(newState State) {
+func (b *LocalBackend) enterState(newState ipn.State) {
 	b.mu.Lock()
 	state := b.state
 	b.state = newState
@@ -1306,19 +1456,19 @@ func (b *LocalBackend) enterState(newState State) {
 	b.logf("Switching ipn state %v -> %v (WantRunning=%v)",
 		state, newState, prefs.WantRunning)
 	if notify != nil {
-		b.send(Notify{State: &newState})
+		b.send(ipn.Notify{State: &newState})
 	}
 
 	if bc != nil {
-		bc.SetPaused(newState == Stopped || !networkUp)
+		bc.SetPaused(newState == ipn.Stopped || !networkUp)
 	}
 
 	switch newState {
-	case NeedsLogin:
+	case ipn.NeedsLogin:
 		systemd.Status("Needs login: %s", authURL)
 		b.blockEngineUpdates(true)
 		fallthrough
-	case Stopped:
+	case ipn.Stopped:
 		err := b.e.Reconfig(&wgcfg.Config{}, &router.Config{})
 		if err != nil {
 			b.logf("Reconfig(down): %v", err)
@@ -1327,11 +1477,11 @@ func (b *LocalBackend) enterState(newState State) {
 		if authURL == "" {
 			systemd.Status("Stopped; run 'tailscale up' to log in")
 		}
-	case Starting, NeedsMachineAuth:
+	case ipn.Starting, ipn.NeedsMachineAuth:
 		b.authReconfig()
 		// Needed so that UpdateEndpoints can run
 		b.e.RequestStatus()
-	case Running:
+	case ipn.Running:
 		var addrs []string
 		for _, addr := range b.netMap.Addresses {
 			addrs = append(addrs, addr.IP.String())
@@ -1345,7 +1495,7 @@ func (b *LocalBackend) enterState(newState State) {
 
 // nextState returns the state the backend seems to be in, based on
 // its internal state.
-func (b *LocalBackend) nextState() State {
+func (b *LocalBackend) nextState() ipn.State {
 	b.mu.Lock()
 	b.assertClientLocked()
 	var (
@@ -1361,31 +1511,31 @@ func (b *LocalBackend) nextState() State {
 		if c.AuthCantContinue() {
 			// Auth was interrupted or waiting for URL visit,
 			// so it won't proceed without human help.
-			return NeedsLogin
+			return ipn.NeedsLogin
 		} else {
 			// Auth or map request needs to finish
 			return state
 		}
 	case !wantRunning:
-		return Stopped
+		return ipn.Stopped
 	case !netMap.Expiry.IsZero() && time.Until(netMap.Expiry) <= 0:
-		return NeedsLogin
+		return ipn.NeedsLogin
 	case netMap.MachineStatus != tailcfg.MachineAuthorized:
 		// TODO(crawshaw): handle tailcfg.MachineInvalid
-		return NeedsMachineAuth
-	case state == NeedsMachineAuth:
+		return ipn.NeedsMachineAuth
+	case state == ipn.NeedsMachineAuth:
 		// (if we get here, we know MachineAuthorized == true)
-		return Starting
-	case state == Starting:
+		return ipn.Starting
+	case state == ipn.Starting:
 		if st := b.getEngineStatus(); st.NumLive > 0 || st.LiveDERPs > 0 {
-			return Running
+			return ipn.Running
 		} else {
 			return state
 		}
-	case state == Running:
-		return Running
+	case state == ipn.Running:
+		return ipn.Running
 	default:
-		return Starting
+		return ipn.Starting
 	}
 }
 
@@ -1397,7 +1547,7 @@ func (b *LocalBackend) RequestEngineStatus() {
 // RequestStatus implements Backend.
 func (b *LocalBackend) RequestStatus() {
 	st := b.Status()
-	b.send(Notify{Status: st})
+	b.send(ipn.Notify{Status: st})
 }
 
 // stateMachine updates the state machine state based on other things
@@ -1493,7 +1643,7 @@ func (b *LocalBackend) setNetInfo(ni *tailcfg.NetInfo) {
 	c.SetNetInfo(ni)
 }
 
-func (b *LocalBackend) setNetMapLocked(nm *controlclient.NetworkMap) {
+func (b *LocalBackend) setNetMapLocked(nm *netmap.NetworkMap) {
 	var login string
 	if nm != nil {
 		login = nm.UserProfiles[nm.User].LoginName
@@ -1506,6 +1656,39 @@ func (b *LocalBackend) setNetMapLocked(nm *controlclient.NetworkMap) {
 		b.logf("active login: %v", login)
 		b.activeLogin = login
 	}
+
+	if nm == nil {
+		b.nodeByAddr = nil
+		return
+	}
+
+	// Update the nodeByAddr index.
+	if b.nodeByAddr == nil {
+		b.nodeByAddr = map[netaddr.IP]*tailcfg.Node{}
+	}
+	// First pass, mark everything unwanted.
+	for k := range b.nodeByAddr {
+		b.nodeByAddr[k] = nil
+	}
+	addNode := func(n *tailcfg.Node) {
+		for _, ipp := range n.Addresses {
+			if ipp.IsSingleIP() {
+				b.nodeByAddr[ipp.IP] = n
+			}
+		}
+	}
+	if nm.SelfNode != nil {
+		addNode(nm.SelfNode)
+	}
+	for _, p := range nm.Peers {
+		addNode(p)
+	}
+	// Third pass, actually delete the unwanted items.
+	for k, v := range b.nodeByAddr {
+		if v == nil {
+			delete(b.nodeByAddr, k)
+		}
+	}
 }
 
 // TestOnlyPublicKeys returns the current machine and node public

ipn/ipnlocal/local_test.go

@@ -0,0 +1,173 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ipnlocal
+
+import (
+	"testing"
+
+	"inet.af/netaddr"
+	"tailscale.com/net/tsaddr"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/netmap"
+)
+
+func TestNetworkMapCompare(t *testing.T) {
+	prefix1, err := netaddr.ParseIPPrefix("192.168.0.0/24")
+	if err != nil {
+		t.Fatal(err)
+	}
+	node1 := &tailcfg.Node{Addresses: []netaddr.IPPrefix{prefix1}}
+
+	prefix2, err := netaddr.ParseIPPrefix("10.0.0.0/8")
+	if err != nil {
+		t.Fatal(err)
+	}
+	node2 := &tailcfg.Node{Addresses: []netaddr.IPPrefix{prefix2}}
+
+	tests := []struct {
+		name string
+		a, b *netmap.NetworkMap
+		want bool
+	}{
+		{
+			"both nil",
+			nil,
+			nil,
+			true,
+		},
+		{
+			"b nil",
+			&netmap.NetworkMap{},
+			nil,
+			false,
+		},
+		{
+			"a nil",
+			nil,
+			&netmap.NetworkMap{},
+			false,
+		},
+		{
+			"both default",
+			&netmap.NetworkMap{},
+			&netmap.NetworkMap{},
+			true,
+		},
+		{
+			"names identical",
+			&netmap.NetworkMap{Name: "map1"},
+			&netmap.NetworkMap{Name: "map1"},
+			true,
+		},
+		{
+			"names differ",
+			&netmap.NetworkMap{Name: "map1"},
+			&netmap.NetworkMap{Name: "map2"},
+			false,
+		},
+		{
+			"Peers identical",
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{}},
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{}},
+			true,
+		},
+		{
+			"Peer list length",
+			// length of Peers list differs
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{{}}},
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{}},
+			false,
+		},
+		{
+			"Node names identical",
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
+			true,
+		},
+		{
+			"Node names differ",
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "B"}}},
+			false,
+		},
+		{
+			"Node lists identical",
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
+			true,
+		},
+		{
+			"Node lists differ",
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{node1, node2}},
+			false,
+		},
+		{
+			"Node Users differ",
+			// User field is not checked.
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{User: 0}}},
+			&netmap.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{User: 1}}},
+			true,
+		},
+	}
+	for _, tt := range tests {
+		got := dnsMapsEqual(tt.a, tt.b)
+		if got != tt.want {
+			t.Errorf("%s: Equal = %v; want %v", tt.name, got, tt.want)
+		}
+	}
+}
+
+func TestShrinkDefaultRoute(t *testing.T) {
+	tests := []struct {
+		route string
+		in    []string
+		out   []string
+	}{
+		{
+			route: "0.0.0.0/0",
+			in:    []string{"1.2.3.4", "25.0.0.1"},
+			out: []string{
+				"10.0.0.1",
+				"10.255.255.255",
+				"192.168.0.1",
+				"192.168.255.255",
+				"172.16.0.1",
+				"172.31.255.255",
+				"100.101.102.103",
+				// Some random IPv6 stuff that shouldn't be in a v4
+				// default route.
+				"fe80::",
+				"2601::1",
+			},
+		},
+		{
+			route: "::/0",
+			in:    []string{"::1", "2601::1"},
+			out: []string{
+				"fe80::1",
+				tsaddr.TailscaleULARange().IP.String(),
+			},
+		},
+	}
+
+	for _, test := range tests {
+		def := netaddr.MustParseIPPrefix(test.route)
+		got, err := shrinkDefaultRoute(def)
+		if err != nil {
+			t.Fatalf("shrinkDefaultRoute(%q): %v", test.route, err)
+		}
+		for _, ip := range test.in {
+			if !got.Contains(netaddr.MustParseIP(ip)) {
+				t.Errorf("shrink(%q).Contains(%v) = false, want true", test.route, ip)
+			}
+		}
+		for _, ip := range test.out {
+			if got.Contains(netaddr.MustParseIP(ip)) {
+				t.Errorf("shrink(%q).Contains(%v) = true, want false", test.route, ip)
+			}
+		}
+	}
+}

ipn/ipnlocal/loglines_test.go

@@ -2,18 +2,20 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package ipn
+package ipnlocal
 
 import (
 	"reflect"
 	"testing"
 	"time"
 
-	"tailscale.com/control/controlclient"
+	"tailscale.com/ipn"
+	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/logtail"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tstest"
 	"tailscale.com/types/key"
+	"tailscale.com/types/persist"
 	"tailscale.com/wgengine"
 )
 
@@ -38,10 +40,8 @@ func TestLocalLogLines(t *testing.T) {
 	idA := logid(0xaa)
 
 	// set up a LocalBackend, super bare bones. No functional data.
-	store := &MemoryStore{
-		cache: make(map[StateKey][]byte),
-	}
-	e, err := wgengine.NewFakeUserspaceEngine(logListen.Logf, 0, nil)
+	store := &ipn.MemoryStore{}
+	e, err := wgengine.NewFakeUserspaceEngine(logListen.Logf, 0)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -53,7 +53,7 @@ func TestLocalLogLines(t *testing.T) {
 	defer lb.Shutdown()
 
 	// custom adjustments for required non-nil fields
-	lb.prefs = NewPrefs()
+	lb.prefs = ipn.NewPrefs()
 	lb.hostinfo = &tailcfg.Hostinfo{}
 	// hacky manual override of the usual log-on-change behaviour of keylogf
 	lb.keyLogf = logListen.Logf
@@ -67,8 +67,8 @@ func TestLocalLogLines(t *testing.T) {
 	}
 
 	// log prefs line
-	persist := &controlclient.Persist{}
-	prefs := NewPrefs()
+	persist := &persist.Persist{}
+	prefs := ipn.NewPrefs()
 	prefs.Persist = persist
 	lb.SetPrefs(prefs)
 
@@ -76,7 +76,7 @@ func TestLocalLogLines(t *testing.T) {
 
 	// log peers, peer keys
 	status := &wgengine.Status{
-		Peers: []wgengine.PeerStatus{wgengine.PeerStatus{
+		Peers: []ipnstate.PeerStatusLite{{
 			TxBytes:       10,
 			RxBytes:       10,
 			LastHandshake: time.Now(),

ipn/ipnserver/conn_linux.go

@@ -1,49 +0,0 @@
-// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build linux
-
-package ipnserver
-
-import (
-	"net"
-
-	"golang.org/x/sys/unix"
-	"tailscale.com/types/logger"
-)
-
-func isReadonlyConn(c net.Conn, logf logger.Logf) (ro bool) {
-	ro = true // conservative default for naked returns below
-	uc, ok := c.(*net.UnixConn)
-	if !ok {
-		logf("unexpected connection type %T", c)
-		return
-	}
-	raw, err := uc.SyscallConn()
-	if err != nil {
-		logf("SyscallConn: %v", err)
-		return
-	}
-
-	var cred *unix.Ucred
-	cerr := raw.Control(func(fd uintptr) {
-		cred, err = unix.GetsockoptUcred(int(fd),
-			unix.SOL_SOCKET,
-			unix.SO_PEERCRED)
-	})
-	if cerr != nil {
-		logf("raw.Control: %v", err)
-		return
-	}
-	if err != nil {
-		logf("raw.Control: %v", err)
-		return
-	}
-	if cred.Uid == 0 {
-		// root is not read-only.
-		return false
-	}
-	logf("non-root connection from %v (read-only)", cred.Uid)
-	return true
-}

ipn/ipnserver/conn_no_ucred.go

@@ -1,27 +0,0 @@
-// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build !linux
-
-package ipnserver
-
-import (
-	"net"
-
-	"tailscale.com/types/logger"
-)
-
-func isReadonlyConn(c net.Conn, logf logger.Logf) bool {
-	// Windows doesn't need/use this mechanism, at least yet. It
-	// has a different last-user-wins auth model.
-
-	// And on Darwin, we're not using it yet, as the Darwin
-	// tailscaled port isn't yet done, and unix.Ucred and
-	// unix.GetsockoptUcred aren't in x/sys/unix.
-
-	// TODO(bradfitz): OpenBSD and FreeBSD should implement this too.
-	// But their x/sys/unix package is different than Linux, so
-	// I didn't include it for now.
-	return false
-}

ipn/ipnserver/server.go

@@ -21,12 +21,17 @@ import (
 	"runtime"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"syscall"
 	"time"
 
+	"go4.org/mem"
 	"inet.af/netaddr"
+	"inet.af/peercred"
 	"tailscale.com/control/controlclient"
 	"tailscale.com/ipn"
+	"tailscale.com/ipn/ipnlocal"
+	"tailscale.com/ipn/localapi"
 	"tailscale.com/log/filelogger"
 	"tailscale.com/logtail/backoff"
 	"tailscale.com/net/netstat"
@@ -91,7 +96,7 @@ type Options struct {
 // server is an IPN backend and its set of 0 or more active connections
 // talking to an IPN backend.
 type server struct {
-	b    *ipn.LocalBackend
+	b    *ipnlocal.LocalBackend
 	logf logger.Logf
 	// resetOnZero is whether to call bs.Reset on transition from
 	// 1->0 connections.  That is, this is whether the backend is
@@ -113,10 +118,11 @@ type server struct {
 
 // connIdentity represents the owner of a localhost TCP connection.
 type connIdentity struct {
-	Unknown bool
-	Pid     int
-	UserID  string
-	User    *user.User
+	Unknown    bool
+	Pid        int
+	UserID     string
+	User       *user.User
+	IsUnixSock bool
 }
 
 // getConnIdentity returns the localhost TCP connection's identity information
@@ -125,7 +131,9 @@ type connIdentity struct {
 // to be able to map it and couldn't.
 func (s *server) getConnIdentity(c net.Conn) (ci connIdentity, err error) {
 	if runtime.GOOS != "windows" { // for now; TODO: expand to other OSes
-		return connIdentity{Unknown: true}, nil
+		ci = connIdentity{Unknown: true}
+		_, ci.IsUnixSock = c.(*net.UnixConn)
+		return ci, nil
 	}
 	la, err := netaddr.ParseIPPort(c.LocalAddr().String())
 	if err != nil {
@@ -216,13 +224,22 @@ func (s *server) blockWhileInUse(conn io.Reader, ci connIdentity) {
 	}
 }
 
+// bufferHasHTTPRequest reports whether br looks like it has an HTTP
+// request in it, without reading any bytes from it.
+func bufferHasHTTPRequest(br *bufio.Reader) bool {
+	peek, _ := br.Peek(br.Buffered())
+	return mem.HasPrefix(mem.B(peek), mem.S("GET ")) ||
+		mem.HasPrefix(mem.B(peek), mem.S("POST ")) ||
+		mem.Contains(mem.B(peek), mem.S(" HTTP/"))
+}
+
 func (s *server) serveConn(ctx context.Context, c net.Conn, logf logger.Logf) {
 	// First see if it's an HTTP request.
 	br := bufio.NewReader(c)
 	c.SetReadDeadline(time.Now().Add(time.Second))
-	peek, _ := br.Peek(4)
+	br.Peek(4)
 	c.SetReadDeadline(time.Time{})
-	isHTTPReq := string(peek) == "GET "
+	isHTTPReq := bufferHasHTTPRequest(br)
 
 	ci, err := s.addConn(c, isHTTPReq)
 	if err != nil {
@@ -249,7 +266,7 @@ func (s *server) serveConn(ctx context.Context, c net.Conn, logf logger.Logf) {
 	s.b.SetCurrentUserID(ci.UserID)
 
 	if isHTTPReq {
-		httpServer := http.Server{
+		httpServer := &http.Server{
 			// Localhost connections are cheap; so only do
 			// keep-alives for a short period of time, as these
 			// active connections lock the server into only serving
@@ -294,6 +311,75 @@ func (s *server) serveConn(ctx context.Context, c net.Conn, logf logger.Logf) {
 	}
 }
 
+func isReadonlyConn(c net.Conn, logf logger.Logf) bool {
+	if runtime.GOOS == "windows" {
+		// Windows doesn't need/use this mechanism, at least yet. It
+		// has a different last-user-wins auth model.
+		return false
+	}
+	const ro = true
+	const rw = false
+	creds, err := peercred.Get(c)
+	if err != nil {
+		logf("connection from unknown peer; read-only")
+		return ro
+	}
+	uid, ok := creds.UserID()
+	if !ok {
+		logf("connection from peer with unknown userid; read-only")
+		return ro
+	}
+	if uid == "0" {
+		logf("connection from userid %v; root has access", uid)
+		return rw
+	}
+	var adminGroupID string
+	switch runtime.GOOS {
+	case "darwin":
+		adminGroupID = darwinAdminGroupID()
+	default:
+		logf("connection from userid %v; read-only", uid)
+		return ro
+	}
+	if adminGroupID == "" {
+		logf("connection from userid %v; no system admin group found, read-only", uid)
+		return ro
+	}
+	u, err := user.LookupId(uid)
+	if err != nil {
+		logf("connection from userid %v; failed to look up user; read-only", uid)
+		return ro
+	}
+	gids, err := u.GroupIds()
+	if err != nil {
+		logf("connection from userid %v; failed to look up groups; read-only", uid)
+		return ro
+	}
+	for _, gid := range gids {
+		if gid == adminGroupID {
+			logf("connection from userid %v; is local admin, has access", uid)
+			return rw
+		}
+	}
+	logf("connection from userid %v; read-only", uid)
+	return ro
+}
+
+var darwinAdminGroupIDCache atomic.Value // of string
+
+func darwinAdminGroupID() string {
+	s, _ := darwinAdminGroupIDCache.Load().(string)
+	if s != "" {
+		return s
+	}
+	g, err := user.LookupGroup("admin")
+	if err != nil {
+		return ""
+	}
+	darwinAdminGroupIDCache.Store(g.Gid)
+	return g.Gid
+}
+
 // inUseOtherUserError is the error type for when the server is in use
 // by a different local user.
 type inUseOtherUserError struct{ error }
@@ -503,41 +589,6 @@ func Run(ctx context.Context, logf logger.Logf, logid string, getEngine func() (
 	}()
 	logf("Listening on %v", listen.Addr())
 
-	bo := backoff.NewBackoff("ipnserver", logf, 30*time.Second)
-	var unservedConn net.Conn // if non-nil, accepted, but hasn't served yet
-
-	eng, err := getEngine()
-	if err != nil {
-		logf("ipnserver: initial getEngine call: %v", err)
-		for i := 1; ctx.Err() == nil; i++ {
-			c, err := listen.Accept()
-			if err != nil {
-				logf("%d: Accept: %v", i, err)
-				bo.BackOff(ctx, err)
-				continue
-			}
-			logf("ipnserver: try%d: trying getEngine again...", i)
-			eng, err = getEngine()
-			if err == nil {
-				logf("%d: GetEngine worked; exiting failure loop", i)
-				unservedConn = c
-				break
-			}
-			logf("ipnserver%d: getEngine failed again: %v", i, err)
-			errMsg := err.Error()
-			go func() {
-				defer c.Close()
-				serverToClient := func(b []byte) { ipn.WriteMsg(c, b) }
-				bs := ipn.NewBackendServer(logf, nil, serverToClient)
-				bs.SendErrorMessage(errMsg)
-				time.Sleep(time.Second)
-			}()
-		}
-		if err := ctx.Err(); err != nil {
-			return err
-		}
-	}
-
 	var store ipn.StateStore
 	if opts.StatePath != "" {
 		store, err = ipn.NewFileStore(opts.StatePath)
@@ -566,7 +617,83 @@ func Run(ctx context.Context, logf logger.Logf, logid string, getEngine func() (
 		store = &ipn.MemoryStore{}
 	}
 
-	b, err := ipn.NewLocalBackend(logf, logid, store, eng)
+	bo := backoff.NewBackoff("ipnserver", logf, 30*time.Second)
+	var unservedConn net.Conn // if non-nil, accepted, but hasn't served yet
+
+	eng, err := getEngine()
+	if err != nil {
+		logf("ipnserver: initial getEngine call: %v", err)
+
+		// Issue 1187: on Windows, in unattended mode,
+		// sometimes we try 5 times and fail to create the
+		// engine before the system's ready. Hack until the
+		// bug if fixed properly: if we're running in
+		// unattended mode on Windows, keep trying forever,
+		// waiting for the machine to be ready (networking to
+		// come up?) and then dial our own safesocket TCP
+		// listener to wake up the usual mechanism that lets
+		// us surface getEngine errors to UI clients. (We
+		// don't want to just call getEngine in a loop without
+		// the listener.Accept, as we do want to handle client
+		// connections so we can tell them about errors)
+
+		bootRaceWaitForEngine, bootRaceWaitForEngineCancel := context.WithTimeout(context.Background(), time.Minute)
+		if runtime.GOOS == "windows" && opts.AutostartStateKey != "" {
+			logf("ipnserver: in unattended mode, waiting for engine availability")
+			getEngine = getEngineUntilItWorksWrapper(getEngine)
+			// Wait for it to be ready.
+			go func() {
+				defer bootRaceWaitForEngineCancel()
+				t0 := time.Now()
+				for {
+					time.Sleep(10 * time.Second)
+					if _, err := getEngine(); err != nil {
+						logf("ipnserver: unattended mode engine load: %v", err)
+						continue
+					}
+					c, err := net.Dial("tcp", listen.Addr().String())
+					logf("ipnserver: engine created after %v; waking up Accept: Dial error: %v", time.Since(t0).Round(time.Second), err)
+					if err == nil {
+						c.Close()
+					}
+					break
+				}
+			}()
+		} else {
+			bootRaceWaitForEngineCancel()
+		}
+
+		for i := 1; ctx.Err() == nil; i++ {
+			c, err := listen.Accept()
+			if err != nil {
+				logf("%d: Accept: %v", i, err)
+				bo.BackOff(ctx, err)
+				continue
+			}
+			<-bootRaceWaitForEngine.Done()
+			logf("ipnserver: try%d: trying getEngine again...", i)
+			eng, err = getEngine()
+			if err == nil {
+				logf("%d: GetEngine worked; exiting failure loop", i)
+				unservedConn = c
+				break
+			}
+			logf("ipnserver%d: getEngine failed again: %v", i, err)
+			errMsg := err.Error()
+			go func() {
+				defer c.Close()
+				serverToClient := func(b []byte) { ipn.WriteMsg(c, b) }
+				bs := ipn.NewBackendServer(logf, nil, serverToClient)
+				bs.SendErrorMessage(errMsg)
+				time.Sleep(time.Second)
+			}()
+		}
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+	}
+
+	b, err := ipnlocal.NewLocalBackend(logf, logid, store, eng)
 	if err != nil {
 		return fmt.Errorf("NewLocalBackend: %v", err)
 	}
@@ -579,6 +706,9 @@ func Run(ctx context.Context, logf logger.Logf, logid string, getEngine func() (
 		opts.DebugMux.HandleFunc("/debug/ipn", func(w http.ResponseWriter, r *http.Request) {
 			serveHTMLStatus(w, b)
 		})
+		h := localapi.NewHandler(b)
+		h.PermitRead = true
+		opts.DebugMux.Handle("/localapi/", h)
 	}
 
 	server.b = b
@@ -756,6 +886,27 @@ func FixedEngine(eng wgengine.Engine) func() (wgengine.Engine, error) {
 	return func() (wgengine.Engine, error) { return eng, nil }
 }
 
+// getEngineUntilItWorksWrapper returns a getEngine wrapper that does
+// not call getEngine concurrently and stops calling getEngine once
+// it's returned a working engine.
+func getEngineUntilItWorksWrapper(getEngine func() (wgengine.Engine, error)) func() (wgengine.Engine, error) {
+	var mu sync.Mutex
+	var engGood wgengine.Engine
+	return func() (wgengine.Engine, error) {
+		mu.Lock()
+		defer mu.Unlock()
+		if engGood != nil {
+			return engGood, nil
+		}
+		e, err := getEngine()
+		if err != nil {
+			return nil, err
+		}
+		engGood = e
+		return e, nil
+	}
+}
+
 type dummyAddr string
 type oneConnListener struct {
 	conn net.Conn
@@ -798,6 +949,13 @@ func (psc *protoSwitchConn) Close() error {
 
 func (s *server) localhostHandler(ci connIdentity) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if ci.IsUnixSock && strings.HasPrefix(r.URL.Path, "/localapi/") {
+			h := localapi.NewHandler(s.b)
+			h.PermitRead = true
+			h.PermitWrite = false // TODO: flesh out connIdentity on more platforms then set this
+			h.ServeHTTP(w, r)
+			return
+		}
 		if ci.Unknown {
 			io.WriteString(w, "<html><title>Tailscale</title><body><h1>Tailscale</h1>This is the local Tailscale daemon.")
 			return
@@ -806,7 +964,7 @@ func (s *server) localhostHandler(ci connIdentity) http.Handler {
 	})
 }
 
-func serveHTMLStatus(w http.ResponseWriter, b *ipn.LocalBackend) {
+func serveHTMLStatus(w http.ResponseWriter, b *ipnlocal.LocalBackend) {
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
 	st := b.Status()
 	// TODO(bradfitz): add LogID and opts to st?

ipn/ipnserver/server_test.go

@@ -56,7 +56,7 @@ func TestRunMultipleAccepts(t *testing.T) {
 		}
 	}
 
-	eng, err := wgengine.NewFakeUserspaceEngine(logf, 0, nil)
+	eng, err := wgengine.NewFakeUserspaceEngine(logf, 0)
 	if err != nil {
 		t.Fatal(err)
 	}

ipn/ipnstate/ipnstate.go

@@ -21,14 +21,21 @@ import (
 	"inet.af/netaddr"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/key"
+	"tailscale.com/util/dnsname"
 )
 
 // Status represents the entire state of the IPN network.
 type Status struct {
-	BackendState   string
-	TailscaleIPs   []netaddr.IP // Tailscale IP(s) assigned to this node
-	Self           *PeerStatus
-	MagicDNSSuffix string // e.g. "userfoo.tailscale.net" (no surrounding dots)
+	BackendState string
+	TailscaleIPs []netaddr.IP // Tailscale IP(s) assigned to this node
+	Self         *PeerStatus
+
+	// MagicDNSSuffix is the network's MagicDNS suffix for nodes
+	// in the network such as "userfoo.tailscale.net".
+	// There are no surrounding dots.
+	// MagicDNSSuffix should be populated regardless of whether a domain
+	// has MagicDNS enabled.
+	MagicDNSSuffix string
 
 	Peer map[key.Public]*PeerStatus
 	User map[tailcfg.UserID]tailcfg.UserProfile
@@ -43,6 +50,12 @@ func (s *Status) Peers() []key.Public {
 	return kk
 }
 
+type PeerStatusLite struct {
+	TxBytes, RxBytes int64
+	LastHandshake    time.Time
+	NodeKey          tailcfg.NodeKey
+}
+
 type PeerStatus struct {
 	PublicKey key.Public
 	HostName  string // HostInfo's Hostname (not a DNS name or necessarily unique)
@@ -64,6 +77,7 @@ type PeerStatus struct {
 	LastSeen      time.Time // last seen to tailcontrol
 	LastHandshake time.Time // with local wireguard
 	KeepAlive     bool
+	ExitNode      bool // true if this is the currently selected exit node.
 
 	// ShareeNode indicates this node exists in the netmap because
 	// it's owned by a shared-to user and that node might connect
@@ -84,14 +98,6 @@ type PeerStatus struct {
 	InEngine bool
 }
 
-// SimpleHostName returns a potentially simplified version of ps.HostName for display purposes.
-func (ps *PeerStatus) SimpleHostName() string {
-	n := ps.HostName
-	n = strings.TrimSuffix(n, ".local")
-	n = strings.TrimSuffix(n, ".localdomain")
-	return n
-}
-
 type StatusBuilder struct {
 	mu     sync.Mutex
 	locked bool
@@ -231,6 +237,9 @@ func (sb *StatusBuilder) AddPeer(peer key.Public, st *PeerStatus) {
 	if st.KeepAlive {
 		e.KeepAlive = true
 	}
+	if st.ExitNode {
+		e.ExitNode = true
+	}
 	if st.ShareeNode {
 		e.ShareeNode = true
 	}
@@ -274,13 +283,22 @@ table tbody tr:nth-child(even) td { background-color: #f5f5f5; }
 	f("<p>Tailscale IP: %s", strings.Join(ips, ", "))
 
 	f("<table>\n<thead>\n")
-	f("<tr><th>Peer</th><th>Node</th><th>Owner</th><th>Rx</th><th>Tx</th><th>Activity</th><th>Endpoints</th></tr>\n")
+	f("<tr><th>Peer</th><th>OS</th><th>Node</th><th>Owner</th><th>Rx</th><th>Tx</th><th>Activity</th><th>Connection</th></tr>\n")
 	f("</thead>\n<tbody>\n")
 
 	now := time.Now()
 
+	var peers []*PeerStatus
 	for _, peer := range st.Peers() {
 		ps := st.Peer[peer]
+		if ps.ShareeNode {
+			continue
+		}
+		peers = append(peers, ps)
+	}
+	SortPeers(peers)
+
+	for _, ps := range peers {
 		var actAgo string
 		if !ps.LastWrite.IsZero() {
 			ago := now.Sub(ps.LastWrite)
@@ -296,40 +314,41 @@ table tbody tr:nth-child(even) td { background-color: #f5f5f5; }
 				owner = owner[:i]
 			}
 		}
-		f("<tr><td>%s</td><td>%s %s<br><span class=\"tailaddr\">%s</span></td><td class=\"acenter owner\">%s</td><td class=\"aright\">%v</td><td class=\"aright\">%v</td><td class=\"aright\">%v</td>",
-			peer.ShortString(),
-			html.EscapeString(ps.SimpleHostName()),
+
+		hostName := dnsname.SanitizeHostname(ps.HostName)
+		dnsName := dnsname.TrimSuffix(ps.DNSName, st.MagicDNSSuffix)
+		if strings.EqualFold(dnsName, hostName) || ps.UserID != st.Self.UserID {
+			hostName = ""
+		}
+		var hostNameHTML string
+		if hostName != "" {
+			hostNameHTML = "<br>" + html.EscapeString(hostName)
+		}
+
+		f("<tr><td>%s</td><td class=acenter>%s</td>"+
+			"<td><b>%s</b>%s<div class=\"tailaddr\">%s</div></td><td class=\"acenter owner\">%s</td><td class=\"aright\">%v</td><td class=\"aright\">%v</td><td class=\"aright\">%v</td>",
+			ps.PublicKey.ShortString(),
 			osEmoji(ps.OS),
+			html.EscapeString(dnsName),
+			hostNameHTML,
 			ps.TailAddr,
 			html.EscapeString(owner),
 			ps.RxBytes,
 			ps.TxBytes,
 			actAgo,
 		)
-		f("<td class=\"aright\">")
+		f("<td>")
+
 		// TODO: let server report this active bool instead
 		active := !ps.LastWrite.IsZero() && time.Since(ps.LastWrite) < 2*time.Minute
-		relay := ps.Relay
-		if relay != "" {
-			if active && ps.CurAddr == "" {
-				f("🔗 <b>derp-%v</b><br>", html.EscapeString(relay))
-			} else {
-				f("derp-%v<br>", html.EscapeString(relay))
+		if active {
+			if ps.Relay != "" && ps.CurAddr == "" {
+				f("relay <b>%s</b>", html.EscapeString(ps.Relay))
+			} else if ps.CurAddr != "" {
+				f("direct <b>%s</b>", html.EscapeString(ps.CurAddr))
 			}
 		}
 
-		match := false
-		for _, addr := range ps.Addrs {
-			if addr == ps.CurAddr {
-				match = true
-				f("🔗 <b>%s</b><br>", addr)
-			} else {
-				f("%s<br>", addr)
-			}
-		}
-		if ps.CurAddr != "" && !match {
-			f("<b>%s</b> \xf0\x9f\xa7\xb3<br>", ps.CurAddr)
-		}
 		f("</td>") // end Addrs
 
 		f("</tr>\n")
@@ -375,3 +394,17 @@ type PingResult struct {
 
 	// TODO(bradfitz): details like whether port mapping was used on either side? (Once supported)
 }
+
+func SortPeers(peers []*PeerStatus) {
+	sort.Slice(peers, func(i, j int) bool { return sortKey(peers[i]) < sortKey(peers[j]) })
+}
+
+func sortKey(ps *PeerStatus) string {
+	if ps.DNSName != "" {
+		return ps.DNSName
+	}
+	if ps.HostName != "" {
+		return ps.HostName
+	}
+	return ps.TailAddr
+}

ipn/local_test.go

@@ -1,119 +0,0 @@
-// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package ipn
-
-import (
-	"inet.af/netaddr"
-	"tailscale.com/control/controlclient"
-	"tailscale.com/tailcfg"
-	"testing"
-)
-
-func TestNetworkMapCompare(t *testing.T) {
-	prefix1, err := netaddr.ParseIPPrefix("192.168.0.0/24")
-	if err != nil {
-		t.Fatal(err)
-	}
-	node1 := &tailcfg.Node{Addresses: []netaddr.IPPrefix{prefix1}}
-
-	prefix2, err := netaddr.ParseIPPrefix("10.0.0.0/8")
-	if err != nil {
-		t.Fatal(err)
-	}
-	node2 := &tailcfg.Node{Addresses: []netaddr.IPPrefix{prefix2}}
-
-	tests := []struct {
-		name string
-		a, b *controlclient.NetworkMap
-		want bool
-	}{
-		{
-			"both nil",
-			nil,
-			nil,
-			true,
-		},
-		{
-			"b nil",
-			&controlclient.NetworkMap{},
-			nil,
-			false,
-		},
-		{
-			"a nil",
-			nil,
-			&controlclient.NetworkMap{},
-			false,
-		},
-		{
-			"both default",
-			&controlclient.NetworkMap{},
-			&controlclient.NetworkMap{},
-			true,
-		},
-		{
-			"names identical",
-			&controlclient.NetworkMap{Name: "map1"},
-			&controlclient.NetworkMap{Name: "map1"},
-			true,
-		},
-		{
-			"names differ",
-			&controlclient.NetworkMap{Name: "map1"},
-			&controlclient.NetworkMap{Name: "map2"},
-			false,
-		},
-		{
-			"Peers identical",
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{}},
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{}},
-			true,
-		},
-		{
-			"Peer list length",
-			// length of Peers list differs
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{{}}},
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{}},
-			false,
-		},
-		{
-			"Node names identical",
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
-			true,
-		},
-		{
-			"Node names differ",
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "A"}}},
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{Name: "B"}}},
-			false,
-		},
-		{
-			"Node lists identical",
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
-			true,
-		},
-		{
-			"Node lists differ",
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{node1, node1}},
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{node1, node2}},
-			false,
-		},
-		{
-			"Node Users differ",
-			// User field is not checked.
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{User: 0}}},
-			&controlclient.NetworkMap{Peers: []*tailcfg.Node{&tailcfg.Node{User: 1}}},
-			true,
-		},
-	}
-	for _, tt := range tests {
-		got := dnsMapsEqual(tt.a, tt.b)
-		if got != tt.want {
-			t.Errorf("%s: Equal = %v; want %v", tt.name, got, tt.want)
-		}
-	}
-}

ipn/localapi/localapi.go

@@ -0,0 +1,95 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package localapi contains the HTTP server handlers for tailscaled's API server.
+package localapi
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+
+	"inet.af/netaddr"
+	"tailscale.com/ipn/ipnlocal"
+	"tailscale.com/tailcfg"
+)
+
+func NewHandler(b *ipnlocal.LocalBackend) *Handler {
+	return &Handler{b: b}
+}
+
+type Handler struct {
+	// RequiredPassword, if non-empty, forces all HTTP
+	// requests to have HTTP basic auth with this password.
+	// It's used by the sandboxed macOS sameuserproof GUI auth mechanism.
+	RequiredPassword string
+
+	// PermitRead is whether read-only HTTP handlers are allowed.
+	PermitRead bool
+
+	// PermitWrite is whether mutating HTTP handlers are allowed.
+	PermitWrite bool
+
+	b *ipnlocal.LocalBackend
+}
+
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if h.b == nil {
+		http.Error(w, "server has no local backend", http.StatusInternalServerError)
+		return
+	}
+	if h.RequiredPassword != "" {
+		_, pass, ok := r.BasicAuth()
+		if !ok {
+			http.Error(w, "auth required", http.StatusUnauthorized)
+			return
+		}
+		if pass != h.RequiredPassword {
+			http.Error(w, "bad password", http.StatusForbidden)
+			return
+		}
+	}
+	switch r.URL.Path {
+	case "/localapi/v0/whois":
+		h.serveWhoIs(w, r)
+	default:
+		io.WriteString(w, "tailscaled\n")
+	}
+}
+
+func (h *Handler) serveWhoIs(w http.ResponseWriter, r *http.Request) {
+	if !h.PermitRead {
+		http.Error(w, "whois access denied", http.StatusForbidden)
+		return
+	}
+	b := h.b
+	var ip netaddr.IP
+	if v := r.FormValue("ip"); v != "" {
+		var err error
+		ip, err = netaddr.ParseIP(r.FormValue("ip"))
+		if err != nil {
+			http.Error(w, "invalid 'ip' parameter", 400)
+			return
+		}
+	} else {
+		http.Error(w, "missing 'ip' parameter", 400)
+		return
+	}
+	n, u, ok := b.WhoIs(ip)
+	if !ok {
+		http.Error(w, "no match for IP", 404)
+		return
+	}
+	res := &tailcfg.WhoIsResponse{
+		Node:        n,
+		UserProfile: &u,
+	}
+	j, err := json.MarshalIndent(res, "", "\t")
+	if err != nil {
+		http.Error(w, "JSON encoding error", 500)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.Write(j)
+}

ipn/message.go

@@ -146,6 +146,10 @@ func (bs *BackendServer) GotFakeCommand(ctx context.Context, cmd *Command) error
 	return bs.GotCommand(ctx, cmd)
 }
 
+// ErrMsgPermissionDenied is the Notify.ErrMessage value used an
+// operation was done from a user/context that didn't have permission.
+const ErrMsgPermissionDenied = "permission denied"
+
 func (bs *BackendServer) GotCommand(ctx context.Context, cmd *Command) error {
 	if cmd.Version != version.Long && !cmd.AllowVersionSkew {
 		vs := fmt.Sprintf("GotCommand: Version mismatch! frontend=%#v backend=%#v",
@@ -178,7 +182,7 @@ func (bs *BackendServer) GotCommand(ctx context.Context, cmd *Command) error {
 	}
 
 	if IsReadonlyContext(ctx) {
-		msg := "permission denied"
+		msg := ErrMsgPermissionDenied
 		bs.send(Notify{ErrMessage: &msg})
 		return nil
 	}

ipn/message_test.go

@@ -16,9 +16,7 @@ import (
 
 func TestReadWrite(t *testing.T) {
 	tstest.PanicOnLog()
-
-	rc := tstest.NewResourceCheck()
-	defer rc.Assert(t)
+	tstest.ResourceCheck(t)
 
 	buf := bytes.Buffer{}
 	err := WriteMsg(&buf, []byte("Test string1"))
@@ -64,9 +62,7 @@ func TestReadWrite(t *testing.T) {
 
 func TestClientServer(t *testing.T) {
 	tstest.PanicOnLog()
-
-	rc := tstest.NewResourceCheck()
-	defer rc.Assert(t)
+	tstest.ResourceCheck(t)
 
 	b := &FakeBackend{}
 	var bs *BackendServer

ipn/prefs.go

@@ -17,8 +17,9 @@ import (
 
 	"inet.af/netaddr"
 	"tailscale.com/atomicfile"
-	"tailscale.com/control/controlclient"
-	"tailscale.com/wgengine/router"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/persist"
+	"tailscale.com/types/preftype"
 )
 
 //go:generate go run tailscale.com/cmd/cloner -type=Prefs -output=prefs_clone.go
@@ -28,8 +29,10 @@ type Prefs struct {
 	// ControlURL is the URL of the control server to use.
 	ControlURL string
 
-	// RouteAll specifies whether to accept subnet and default routes
-	// advertised by other nodes on the Tailscale network.
+	// RouteAll specifies whether to accept subnets advertised by
+	// other nodes on the Tailscale network. Note that this does not
+	// include default routes (0.0.0.0/0 and ::/0), those are
+	// controlled by ExitNodeID/IP below.
 	RouteAll bool
 
 	// AllowSingleHosts specifies whether to install routes for each
@@ -44,6 +47,24 @@ type Prefs struct {
 	// packets stop flowing. What's up with that?
 	AllowSingleHosts bool
 
+	// ExitNodeID and ExitNodeIP specify the node that should be used
+	// as an exit node for internet traffic. At most one of these
+	// should be non-zero.
+	//
+	// The preferred way to express the chosen node is ExitNodeID, but
+	// in some cases it's not possible to use that ID (e.g. in the
+	// linux CLI, before tailscaled has a netmap). For those
+	// situations, we allow specifying the exit node by IP, and
+	// ipnlocal.LocalBackend will translate the IP into an ID when the
+	// node is found in the netmap.
+	//
+	// If the selected exit node doesn't exist (e.g. it's not part of
+	// the current tailnet), or it doesn't offer exit node services, a
+	// blackhole route will be installed on the local system to
+	// prevent any traffic escaping to the local network.
+	ExitNodeID tailcfg.StableNodeID
+	ExitNodeIP netaddr.IP
+
 	// CorpDNS specifies whether to install the Tailscale network's
 	// DNS configuration, if it exists.
 	CorpDNS bool
@@ -116,14 +137,14 @@ type Prefs struct {
 
 	// NetfilterMode specifies how much to manage netfilter rules for
 	// Tailscale, if at all.
-	NetfilterMode router.NetfilterMode
+	NetfilterMode preftype.NetfilterMode
 
 	// The Persist field is named 'Config' in the file for backward
 	// compatibility with earlier versions.
 	// TODO(apenwarr): We should move this out of here, it's not a pref.
 	//  We can maybe do that once we're sure which module should persist
 	//  it (backend or frontend?)
-	Persist *controlclient.Persist `json:"Config"`
+	Persist *persist.Persist `json:"Config"`
 }
 
 // IsEmpty reports whether p is nil or pointing to a Prefs zero value.
@@ -147,6 +168,11 @@ func (p *Prefs) pretty(goos string) string {
 	if p.ShieldsUp {
 		sb.WriteString("shields=true ")
 	}
+	if !p.ExitNodeIP.IsZero() {
+		fmt.Fprintf(&sb, "exit=%v ", p.ExitNodeIP)
+	} else if !p.ExitNodeID.IsZero() {
+		fmt.Fprintf(&sb, "exit=%v ", p.ExitNodeID)
+	}
 	if len(p.AdvertiseRoutes) > 0 || goos == "linux" {
 		fmt.Fprintf(&sb, "routes=%v ", p.AdvertiseRoutes)
 	}
@@ -191,6 +217,8 @@ func (p *Prefs) Equals(p2 *Prefs) bool {
 		p.ControlURL == p2.ControlURL &&
 		p.RouteAll == p2.RouteAll &&
 		p.AllowSingleHosts == p2.AllowSingleHosts &&
+		p.ExitNodeID == p2.ExitNodeID &&
+		p.ExitNodeIP == p2.ExitNodeIP &&
 		p.CorpDNS == p2.CorpDNS &&
 		p.WantRunning == p2.WantRunning &&
 		p.NotepadURLs == p2.NotepadURLs &&
@@ -240,7 +268,7 @@ func NewPrefs() *Prefs {
 		AllowSingleHosts: true,
 		CorpDNS:          true,
 		WantRunning:      true,
-		NetfilterMode:    router.NetfilterOn,
+		NetfilterMode:    preftype.NetfilterOn,
 	}
 }
 
@@ -252,7 +280,7 @@ func PrefsFromBytes(b []byte, enforceDefaults bool) (*Prefs, error) {
 	if len(b) == 0 {
 		return p, nil
 	}
-	persist := &controlclient.Persist{}
+	persist := &persist.Persist{}
 	err := json.Unmarshal(b, persist)
 	if err == nil && (persist.Provider != "" || persist.LoginName != "") {
 		// old-style relaynode config; import it

ipn/prefs_clone.go

@@ -8,8 +8,9 @@ package ipn
 
 import (
 	"inet.af/netaddr"
-	"tailscale.com/control/controlclient"
-	"tailscale.com/wgengine/router"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/persist"
+	"tailscale.com/types/preftype"
 )
 
 // Clone makes a deep copy of Prefs.
@@ -23,7 +24,7 @@ func (src *Prefs) Clone() *Prefs {
 	dst.AdvertiseTags = append(src.AdvertiseTags[:0:0], src.AdvertiseTags...)
 	dst.AdvertiseRoutes = append(src.AdvertiseRoutes[:0:0], src.AdvertiseRoutes...)
 	if dst.Persist != nil {
-		dst.Persist = new(controlclient.Persist)
+		dst.Persist = new(persist.Persist)
 		*dst.Persist = *src.Persist
 	}
 	return dst
@@ -35,6 +36,8 @@ var _PrefsNeedsRegeneration = Prefs(struct {
 	ControlURL       string
 	RouteAll         bool
 	AllowSingleHosts bool
+	ExitNodeID       tailcfg.StableNodeID
+	ExitNodeIP       netaddr.IP
 	CorpDNS          bool
 	WantRunning      bool
 	ShieldsUp        bool
@@ -46,6 +49,6 @@ var _PrefsNeedsRegeneration = Prefs(struct {
 	ForceDaemon      bool
 	AdvertiseRoutes  []netaddr.IPPrefix
 	NoSNAT           bool
-	NetfilterMode    router.NetfilterMode
-	Persist          *controlclient.Persist
+	NetfilterMode    preftype.NetfilterMode
+	Persist          *persist.Persist
 }{})

ipn/prefs_test.go

@@ -14,10 +14,11 @@ import (
 	"time"
 
 	"inet.af/netaddr"
-	"tailscale.com/control/controlclient"
+	"tailscale.com/tailcfg"
 	"tailscale.com/tstest"
+	"tailscale.com/types/persist"
+	"tailscale.com/types/preftype"
 	"tailscale.com/types/wgkey"
-	"tailscale.com/wgengine/router"
 )
 
 func fieldsOf(t reflect.Type) (fields []string) {
@@ -30,7 +31,7 @@ func fieldsOf(t reflect.Type) (fields []string) {
 func TestPrefsEqual(t *testing.T) {
 	tstest.PanicOnLog()
 
-	prefsHandles := []string{"ControlURL", "RouteAll", "AllowSingleHosts", "CorpDNS", "WantRunning", "ShieldsUp", "AdvertiseTags", "Hostname", "OSVersion", "DeviceModel", "NotepadURLs", "ForceDaemon", "AdvertiseRoutes", "NoSNAT", "NetfilterMode", "Persist"}
+	prefsHandles := []string{"ControlURL", "RouteAll", "AllowSingleHosts", "ExitNodeID", "ExitNodeIP", "CorpDNS", "WantRunning", "ShieldsUp", "AdvertiseTags", "Hostname", "OSVersion", "DeviceModel", "NotepadURLs", "ForceDaemon", "AdvertiseRoutes", "NoSNAT", "NetfilterMode", "Persist"}
 	if have := fieldsOf(reflect.TypeOf(Prefs{})); !reflect.DeepEqual(have, prefsHandles) {
 		t.Errorf("Prefs.Equal check might be out of sync\nfields: %q\nhandled: %q\n",
 			have, prefsHandles)
@@ -99,6 +100,28 @@ func TestPrefsEqual(t *testing.T) {
 			true,
 		},
 
+		{
+			&Prefs{ExitNodeID: "n1234"},
+			&Prefs{},
+			false,
+		},
+		{
+			&Prefs{ExitNodeID: "n1234"},
+			&Prefs{ExitNodeID: "n1234"},
+			true,
+		},
+
+		{
+			&Prefs{ExitNodeIP: netaddr.MustParseIP("1.2.3.4")},
+			&Prefs{},
+			false,
+		},
+		{
+			&Prefs{ExitNodeIP: netaddr.MustParseIP("1.2.3.4")},
+			&Prefs{ExitNodeIP: netaddr.MustParseIP("1.2.3.4")},
+			true,
+		},
+
 		{
 			&Prefs{CorpDNS: true},
 			&Prefs{CorpDNS: false},
@@ -192,24 +215,24 @@ func TestPrefsEqual(t *testing.T) {
 		},
 
 		{
-			&Prefs{NetfilterMode: router.NetfilterOff},
-			&Prefs{NetfilterMode: router.NetfilterOn},
+			&Prefs{NetfilterMode: preftype.NetfilterOff},
+			&Prefs{NetfilterMode: preftype.NetfilterOn},
 			false,
 		},
 		{
-			&Prefs{NetfilterMode: router.NetfilterOn},
-			&Prefs{NetfilterMode: router.NetfilterOn},
+			&Prefs{NetfilterMode: preftype.NetfilterOn},
+			&Prefs{NetfilterMode: preftype.NetfilterOn},
 			true,
 		},
 
 		{
-			&Prefs{Persist: &controlclient.Persist{}},
-			&Prefs{Persist: &controlclient.Persist{LoginName: "dave"}},
+			&Prefs{Persist: &persist.Persist{}},
+			&Prefs{Persist: &persist.Persist{LoginName: "dave"}},
 			false,
 		},
 		{
-			&Prefs{Persist: &controlclient.Persist{LoginName: "dave"}},
-			&Prefs{Persist: &controlclient.Persist{LoginName: "dave"}},
+			&Prefs{Persist: &persist.Persist{LoginName: "dave"}},
+			&Prefs{Persist: &persist.Persist{LoginName: "dave"}},
 			true,
 		},
 	}
@@ -274,7 +297,7 @@ func TestBasicPrefs(t *testing.T) {
 func TestPrefsPersist(t *testing.T) {
 	tstest.PanicOnLog()
 
-	c := controlclient.Persist{
+	c := persist.Persist{
 		LoginName: "test@example.com",
 	}
 	p := Prefs{
@@ -340,20 +363,34 @@ func TestPrefsPretty(t *testing.T) {
 		},
 		{
 			Prefs{
-				Persist: &controlclient.Persist{},
+				Persist: &persist.Persist{},
 			},
 			"linux",
 			`Prefs{ra=false mesh=false dns=false want=false routes=[] nf=off Persist{lm=, o=, n= u=""}}`,
 		},
 		{
 			Prefs{
-				Persist: &controlclient.Persist{
+				Persist: &persist.Persist{
 					PrivateNodeKey: wgkey.Private{1: 1},
 				},
 			},
 			"linux",
 			`Prefs{ra=false mesh=false dns=false want=false routes=[] nf=off Persist{lm=, o=, n=[B1VKl] u=""}}`,
 		},
+		{
+			Prefs{
+				ExitNodeIP: netaddr.MustParseIP("1.2.3.4"),
+			},
+			"linux",
+			`Prefs{ra=false mesh=false dns=false want=false exit=1.2.3.4 routes=[] nf=off Persist=nil}`,
+		},
+		{
+			Prefs{
+				ExitNodeID: tailcfg.StableNodeID("myNodeABC"),
+			},
+			"linux",
+			`Prefs{ra=false mesh=false dns=false want=false exit=myNodeABC routes=[] nf=off Persist=nil}`,
+		},
 	}
 	for i, tt := range tests {
 		got := tt.p.pretty(tt.os)

logpolicy/logpolicy.go

@@ -17,6 +17,7 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"net/url"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -338,6 +339,18 @@ func New(collection string) *Policy {
 	tryFixLogStateLocation(dir, cmdName)
 
 	cfgPath := filepath.Join(dir, fmt.Sprintf("%s.log.conf", cmdName))
+
+	// The Windows service previously ran as tailscale-ipn.exe, so
+	// let's keep using that log base name if it exists.
+	if runtime.GOOS == "windows" && cmdName == "tailscaled" {
+		const oldCmdName = "tailscale-ipn"
+		oldPath := filepath.Join(dir, oldCmdName+".log.conf")
+		if fi, err := os.Stat(oldPath); err == nil && fi.Mode().IsRegular() {
+			cfgPath = oldPath
+			cmdName = oldCmdName
+		}
+	}
+
 	var oldc *Config
 	data, err := ioutil.ReadFile(cfgPath)
 	if err != nil {
@@ -387,6 +400,13 @@ func New(collection string) *Policy {
 		HTTPC: &http.Client{Transport: newLogtailTransport(logtail.DefaultHost)},
 	}
 
+	if val, ok := os.LookupEnv("TS_LOG_TARGET"); ok {
+		log.Println("You have enabled a non-default log target. Doing without being told to by Tailscale staff or your network administrator will make getting support difficult.")
+		c.BaseURL = val
+		u, _ := url.Parse(val)
+		c.HTTPC = &http.Client{Transport: newLogtailTransport(u.Host)}
+	}
+
 	filchBuf, filchErr := filch.New(filepath.Join(dir, cmdName), filch.Options{})
 	if filchBuf != nil {
 		c.Buffer = filchBuf

logtail/logtail.go

@@ -19,6 +19,7 @@ import (
 
 	"tailscale.com/logtail/backoff"
 	tslogger "tailscale.com/types/logger"
+	"tailscale.com/wgengine/monitor"
 )
 
 // DefaultHost is the default host name to upload logs to when
@@ -106,6 +107,7 @@ type Logger struct {
 	url            string
 	lowMem         bool
 	skipClientTime bool
+	linkMonitor    *monitor.Mon
 	buffer         Buffer
 	sent           chan struct{}   // signal to speed up drain
 	drainLogs      <-chan struct{} // if non-nil, external signal to attempt a drain
@@ -128,6 +130,14 @@ func (l *Logger) SetVerbosityLevel(level int) {
 	l.stderrLevel = level
 }
 
+// SetLinkMonitor sets the optional the link monitor.
+//
+// It should not be changed concurrently with log writes and should
+// only be set once.
+func (l *Logger) SetLinkMonitor(lm *monitor.Mon) {
+	l.linkMonitor = lm
+}
+
 // Shutdown gracefully shuts down the logger while completing any
 // remaining uploads.
 //

net/dnscache/dnscache.go

@@ -8,6 +8,8 @@ package dnscache
 
 import (
 	"context"
+	"crypto/tls"
+	"errors"
 	"fmt"
 	"log"
 	"net"
@@ -18,6 +20,7 @@ import (
 	"time"
 
 	"golang.org/x/sync/singleflight"
+	"inet.af/netaddr"
 )
 
 var single = &Resolver{
@@ -55,6 +58,10 @@ type Resolver struct {
 	// If nil, net.DefaultResolver is used.
 	Forward *net.Resolver
 
+	// LookupIPFallback optionally provides a backup DNS mechanism
+	// to use if Forward returns an error or no results.
+	LookupIPFallback func(ctx context.Context, host string) ([]netaddr.IP, error)
+
 	// TTL is how long to keep entries cached
 	//
 	// If zero, a default (currently 10 minutes) is used.
@@ -198,6 +205,18 @@ func (r *Resolver) lookupIP(host string) (ip, ip6 net.IP, err error) {
 	ctx, cancel := context.WithTimeout(context.Background(), r.lookupTimeoutForHost(host))
 	defer cancel()
 	ips, err := r.fwd().LookupIPAddr(ctx, host)
+	if (err != nil || len(ips) == 0) && r.LookupIPFallback != nil {
+		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+		defer cancel()
+		var fips []netaddr.IP
+		fips, err = r.LookupIPFallback(ctx, host)
+		if err == nil {
+			ips = nil
+			for _, fip := range fips {
+				ips = append(ips, *fip.IPAddr())
+			}
+		}
+	}
 	if err != nil {
 		return nil, nil, err
 	}
@@ -269,13 +288,33 @@ type DialContextFunc func(ctx context.Context, network, address string) (net.Con
 
 // Dialer returns a wrapped DialContext func that uses the provided dnsCache.
 func Dialer(fwd DialContextFunc, dnsCache *Resolver) DialContextFunc {
-	return func(ctx context.Context, network, address string) (net.Conn, error) {
+	return func(ctx context.Context, network, address string) (retConn net.Conn, ret error) {
 		host, port, err := net.SplitHostPort(address)
 		if err != nil {
 			// Bogus. But just let the real dialer return an error rather than
 			// inventing a similar one.
 			return fwd(ctx, network, address)
 		}
+		defer func() {
+			// On any failure, assume our DNS is wrong and try our fallback, if any.
+			if ret == nil || dnsCache.LookupIPFallback == nil {
+				return
+			}
+			ips, err := dnsCache.LookupIPFallback(ctx, host)
+			if err != nil {
+				// Return with original error
+				return
+			}
+			for _, ip := range ips {
+				dst := net.JoinHostPort(ip.String(), port)
+				if c, err := fwd(ctx, network, dst); err == nil {
+					retConn = c
+					ret = nil
+					return
+				}
+			}
+		}()
+
 		ip, ip6, err := dnsCache.LookupIP(ctx, host)
 		if err != nil {
 			return nil, fmt.Errorf("failed to resolve %q: %w", host, err)
@@ -300,3 +339,62 @@ func Dialer(fwd DialContextFunc, dnsCache *Resolver) DialContextFunc {
 		return fwd(ctx, network, dst)
 	}
 }
+
+var errTLSHandshakeTimeout = errors.New("timeout doing TLS handshake")
+
+// TLSDialer is like Dialer but returns a func suitable for using with net/http.Transport.DialTLSContext.
+// It returns a *tls.Conn type on success.
+// On TLS cert validation failure, it can invoke a backup DNS resolution strategy.
+func TLSDialer(fwd DialContextFunc, dnsCache *Resolver, tlsConfigBase *tls.Config) DialContextFunc {
+	tcpDialer := Dialer(fwd, dnsCache)
+	return func(ctx context.Context, network, address string) (net.Conn, error) {
+		host, _, err := net.SplitHostPort(address)
+		if err != nil {
+			return nil, err
+		}
+		tcpConn, err := tcpDialer(ctx, network, address)
+		if err != nil {
+			return nil, err
+		}
+
+		cfg := cloneTLSConfig(tlsConfigBase)
+		if cfg.ServerName == "" {
+			cfg.ServerName = host
+		}
+		tlsConn := tls.Client(tcpConn, cfg)
+
+		errc := make(chan error, 2)
+		handshakeCtx, handshakeTimeoutCancel := context.WithTimeout(ctx, 5*time.Second)
+		defer handshakeTimeoutCancel()
+		done := make(chan bool)
+		defer close(done)
+		go func() {
+			select {
+			case <-done:
+			case <-handshakeCtx.Done():
+				errc <- errTLSHandshakeTimeout
+			}
+		}()
+		go func() {
+			err := tlsConn.Handshake()
+			handshakeTimeoutCancel()
+			errc <- err
+		}()
+		if err := <-errc; err != nil {
+			tcpConn.Close()
+			// TODO: if err != errTLSHandshakeTimeout,
+			// assume it might be some captive portal or
+			// otherwise incorrect DNS and try the backup
+			// DNS mechanism.
+			return nil, err
+		}
+		return tlsConn, nil
+	}
+}
+
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+	return cfg.Clone()
+}

net/dnsfallback/dnsfallback.go

@@ -0,0 +1,103 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package dnsfallback contains a DNS fallback mechanism
+// for starting up Tailscale when the system DNS is broken or otherwise unavailable.
+package dnsfallback
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log"
+	"math/rand"
+	"net"
+	"net/http"
+	"net/url"
+	"time"
+
+	"inet.af/netaddr"
+	"tailscale.com/derp/derpmap"
+	"tailscale.com/net/netns"
+	"tailscale.com/net/tshttpproxy"
+)
+
+func Lookup(ctx context.Context, host string) ([]netaddr.IP, error) {
+	type nameIP struct {
+		dnsName string
+		ip      netaddr.IP
+	}
+
+	var cands []nameIP
+	dm := derpmap.Prod()
+	for _, dr := range dm.Regions {
+		for _, n := range dr.Nodes {
+			if ip, err := netaddr.ParseIP(n.IPv4); err == nil {
+				cands = append(cands, nameIP{n.HostName, ip})
+			}
+			if ip, err := netaddr.ParseIP(n.IPv6); err == nil {
+				cands = append(cands, nameIP{n.HostName, ip})
+			}
+		}
+	}
+	rand.Shuffle(len(cands), func(i, j int) {
+		cands[i], cands[j] = cands[j], cands[i]
+	})
+	if len(cands) == 0 {
+		return nil, fmt.Errorf("no DNS fallback options for %q", host)
+	}
+	for ctx.Err() == nil && len(cands) > 0 {
+		cand := cands[0]
+		log.Printf("trying bootstrapDNS(%q, %q) for %q ...", cand.dnsName, cand.ip, host)
+		ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
+		defer cancel()
+		dm, err := bootstrapDNSMap(ctx, cand.dnsName, cand.ip, host)
+		if err != nil {
+			log.Printf("bootstrapDNS(%q, %q) for %q error: %v", cand.dnsName, cand.ip, host, err)
+			continue
+		}
+		if ips := dm[host]; len(ips) > 0 {
+			log.Printf("bootstrapDNS(%q, %q) for %q = %v", cand.dnsName, cand.ip, host, ips)
+			return ips, nil
+		}
+	}
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	return nil, fmt.Errorf("no DNS fallback candidates remain for %q", host)
+}
+
+// serverName and serverIP of are, say, "derpN.tailscale.com".
+// queryName is the name being sought (e.g. "login.tailscale.com"), passed as hint.
+func bootstrapDNSMap(ctx context.Context, serverName string, serverIP netaddr.IP, queryName string) (dnsMap, error) {
+	dialer := netns.NewDialer()
+	tr := http.DefaultTransport.(*http.Transport).Clone()
+	tr.Proxy = tshttpproxy.ProxyFromEnvironment
+	tr.DialContext = func(ctx context.Context, netw, addr string) (net.Conn, error) {
+		return dialer.DialContext(ctx, "tcp", net.JoinHostPort(serverIP.String(), "443"))
+	}
+	c := &http.Client{Transport: tr}
+	req, err := http.NewRequestWithContext(ctx, "GET", "https://"+serverName+"/bootstrap-dns?q="+url.QueryEscape(queryName), nil)
+	if err != nil {
+		return nil, err
+	}
+	dm := make(dnsMap)
+	res, err := c.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	if res.StatusCode != 200 {
+		return nil, errors.New(res.Status)
+	}
+	if err := json.NewDecoder(res.Body).Decode(&dm); err != nil {
+		return nil, err
+	}
+	return dm, nil
+}
+
+// dnsMap is the JSON type returned by the DERP /bootstrap-dns handler:
+// https://derp10.tailscale.com/bootstrap-dns
+type dnsMap map[string][]netaddr.IP

net/interfaces/interfaces.go

@@ -10,6 +10,7 @@ import (
 	"net"
 	"net/http"
 	"reflect"
+	"runtime"
 	"sort"
 	"strings"
 
@@ -39,8 +40,11 @@ func Tailscale() (net.IP, *net.Interface, error) {
 			continue
 		}
 		for _, a := range addrs {
-			if ipnet, ok := a.(*net.IPNet); ok && IsTailscaleIP(ipnet.IP) {
-				return ipnet.IP, &iface, nil
+			if ipnet, ok := a.(*net.IPNet); ok {
+				nip, ok := netaddr.FromStdIP(ipnet.IP)
+				if ok && tsaddr.IsTailscaleIP(nip) {
+					return ipnet.IP, &iface, nil
+				}
 			}
 		}
 	}
@@ -57,16 +61,21 @@ func maybeTailscaleInterfaceName(s string) bool {
 		strings.HasPrefix(s, "utun")
 }
 
-// IsTailscaleIP reports whether ip is an IP in a range used by
-// Tailscale virtual network interfaces.
-func IsTailscaleIP(ip net.IP) bool {
-	nip, _ := netaddr.FromStdIP(ip) // TODO: push this up to caller, change func signature
-	return tsaddr.IsTailscaleIP(nip)
-}
-
 func isUp(nif *net.Interface) bool       { return nif.Flags&net.FlagUp != 0 }
 func isLoopback(nif *net.Interface) bool { return nif.Flags&net.FlagLoopback != 0 }
 
+func isProblematicInterface(nif *net.Interface) bool {
+	name := nif.Name
+	// Don't try to send disco/etc packets over zerotier; they effectively
+	// DoS each other by doing traffic amplification, both of them
+	// preferring/trying to use each other for transport. See:
+	// https://github.com/tailscale/tailscale/issues/1208
+	if strings.HasPrefix(name, "zt") || (runtime.GOOS == "windows" && strings.Contains(name, "ZeroTier")) {
+		return true
+	}
+	return false
+}
+
 // LocalAddresses returns the machine's IP addresses, separated by
 // whether they're loopback addresses.
 func LocalAddresses() (regular, loopback []string, err error) {
@@ -77,8 +86,10 @@ func LocalAddresses() (regular, loopback []string, err error) {
 	}
 	for i := range ifaces {
 		iface := &ifaces[i]
-		if !isUp(iface) {
-			// Down interfaces don't count
+		if !isUp(iface) || isProblematicInterface(iface) {
+			// Skip down interfaces and ones that are
+			// problematic that we don't want to try to
+			// send Tailscale traffic over.
 			continue
 		}
 		ifcIsLoopback := isLoopback(iface)
@@ -124,8 +135,10 @@ type Interface struct {
 func (i Interface) IsLoopback() bool { return isLoopback(i.Interface) }
 func (i Interface) IsUp() bool       { return isUp(i.Interface) }
 
-// ForeachInterfaceAddress calls fn for each interface's address on the machine.
-func ForeachInterfaceAddress(fn func(Interface, netaddr.IP)) error {
+// ForeachInterfaceAddress calls fn for each interface's address on
+// the machine. The IPPrefix's IP is the IP address assigned to the
+// interface, and Bits are the subnet mask.
+func ForeachInterfaceAddress(fn func(Interface, netaddr.IPPrefix)) error {
 	ifaces, err := net.Interfaces()
 	if err != nil {
 		return err
@@ -139,8 +152,8 @@ func ForeachInterfaceAddress(fn func(Interface, netaddr.IP)) error {
 		for _, a := range addrs {
 			switch v := a.(type) {
 			case *net.IPNet:
-				if ip, ok := netaddr.FromStdIP(v.IP); ok {
-					fn(Interface{iface}, ip)
+				if pfx, ok := netaddr.FromStdIPNet(v); ok {
+					fn(Interface{iface}, pfx)
 				}
 			}
 		}
@@ -148,11 +161,43 @@ func ForeachInterfaceAddress(fn func(Interface, netaddr.IP)) error {
 	return nil
 }
 
+// ForeachInterface calls fn for each interface on the machine, with
+// all its addresses. The IPPrefix's IP is the IP address assigned to
+// the interface, and Bits are the subnet mask.
+func ForeachInterface(fn func(Interface, []netaddr.IPPrefix)) error {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return err
+	}
+	for i := range ifaces {
+		iface := &ifaces[i]
+		addrs, err := iface.Addrs()
+		if err != nil {
+			return err
+		}
+		var pfxs []netaddr.IPPrefix
+		for _, a := range addrs {
+			switch v := a.(type) {
+			case *net.IPNet:
+				if pfx, ok := netaddr.FromStdIPNet(v); ok {
+					pfxs = append(pfxs, pfx)
+				}
+			}
+		}
+		fn(Interface{iface}, pfxs)
+	}
+	return nil
+}
+
 // State is intended to store the state of the machine's network interfaces,
 // routing table, and other network configuration.
 // For now it's pretty basic.
 type State struct {
-	InterfaceIPs map[string][]netaddr.IP
+	// InterfaceIPs maps from an interface name to the IP addresses
+	// configured on that interface. Each address is represented as an
+	// IPPrefix, where the IP is the interface IP address and Bits is
+	// the subnet mask.
+	InterfaceIPs map[string][]netaddr.IPPrefix
 	InterfaceUp  map[string]bool
 
 	// HaveV6Global is whether this machine has an IPv6 global address
@@ -186,10 +231,9 @@ func (s *State) String() string {
 	fmt.Fprintf(&sb, "interfaces.State{defaultRoute=%v ifs={", s.DefaultRouteInterface)
 	ifs := make([]string, 0, len(s.InterfaceUp))
 	for k := range s.InterfaceUp {
-		if allLoopbackIPs(s.InterfaceIPs[k]) {
-			continue
+		if anyInterestingIP(s.InterfaceIPs[k]) {
+			ifs = append(ifs, k)
 		}
-		ifs = append(ifs, k)
 	}
 	sort.Slice(ifs, func(i, j int) bool {
 		upi, upj := s.InterfaceUp[ifs[i]], s.InterfaceUp[ifs[j]]
@@ -206,14 +250,14 @@ func (s *State) String() string {
 		if s.InterfaceUp[ifName] {
 			fmt.Fprintf(&sb, "%s:[", ifName)
 			needSpace := false
-			for _, ip := range s.InterfaceIPs[ifName] {
-				if ip.IsLinkLocalUnicast() {
+			for _, pfx := range s.InterfaceIPs[ifName] {
+				if !isInterestingIP(pfx.IP) {
 					continue
 				}
 				if needSpace {
 					sb.WriteString(" ")
 				}
-				fmt.Fprintf(&sb, "%s", ip)
+				fmt.Fprintf(&sb, "%s", pfx)
 				needSpace = true
 			}
 			sb.WriteString("]")
@@ -249,18 +293,35 @@ func (s *State) AnyInterfaceUp() bool {
 
 // RemoveTailscaleInterfaces modifes s to remove any interfaces that
 // are owned by this process. (TODO: make this true; currently it
-// makes the Linux-only assumption that the interface is named
-// /^tailscale/)
+// uses some heuristics)
 func (s *State) RemoveTailscaleInterfaces() {
-	for name := range s.InterfaceIPs {
-		if isTailscaleInterfaceName(name) {
+	for name, pfxs := range s.InterfaceIPs {
+		if isTailscaleInterface(name, pfxs) {
 			delete(s.InterfaceIPs, name)
 			delete(s.InterfaceUp, name)
 		}
 	}
 }
 
-func isTailscaleInterfaceName(name string) bool {
+func hasTailscaleIP(pfxs []netaddr.IPPrefix) bool {
+	for _, pfx := range pfxs {
+		if tsaddr.IsTailscaleIP(pfx.IP) {
+			return true
+		}
+	}
+	return false
+}
+
+func isTailscaleInterface(name string, ips []netaddr.IPPrefix) bool {
+	if runtime.GOOS == "darwin" && strings.HasPrefix(name, "utun") && hasTailscaleIP(ips) {
+		// On macOS in the sandboxed app (at least as of
+		// 2021-02-25), we often see two utun devices
+		// (e.g. utun4 and utun7) with the same IPv4 and IPv6
+		// addresses. Just remove all utun devices with
+		// Tailscale IPs until we know what's happening with
+		// macOS NetworkExtensions and utun devices.
+		return true
+	}
 	return name == "Tailscale" || // as it is on Windows
 		strings.HasPrefix(name, "tailscale") // TODO: use --tun flag value, etc; see TODO in method doc
 }
@@ -273,16 +334,22 @@ var getPAC func() string
 // It does not set the returned State.IsExpensive. The caller can populate that.
 func GetState() (*State, error) {
 	s := &State{
-		InterfaceIPs: make(map[string][]netaddr.IP),
+		InterfaceIPs: make(map[string][]netaddr.IPPrefix),
 		InterfaceUp:  make(map[string]bool),
 	}
-	if err := ForeachInterfaceAddress(func(ni Interface, ip netaddr.IP) {
+	if err := ForeachInterface(func(ni Interface, pfxs []netaddr.IPPrefix) {
 		ifUp := ni.IsUp()
-		s.InterfaceIPs[ni.Name] = append(s.InterfaceIPs[ni.Name], ip)
 		s.InterfaceUp[ni.Name] = ifUp
-		if ifUp && !ip.IsLoopback() && !ip.IsLinkLocalUnicast() && !isTailscaleInterfaceName(ni.Name) {
-			s.HaveV6Global = s.HaveV6Global || isGlobalV6(ip)
-			s.HaveV4 = s.HaveV4 || ip.Is4()
+		s.InterfaceIPs[ni.Name] = append(s.InterfaceIPs[ni.Name], pfxs...)
+		if !ifUp || isTailscaleInterface(ni.Name, pfxs) {
+			return
+		}
+		for _, pfx := range pfxs {
+			if pfx.IP.IsLoopback() || pfx.IP.IsLinkLocalUnicast() {
+				continue
+			}
+			s.HaveV6Global = s.HaveV6Global || isGlobalV6(pfx.IP)
+			s.HaveV4 = s.HaveV4 || pfx.IP.Is4()
 		}
 	}); err != nil {
 		return nil, err
@@ -316,7 +383,8 @@ func HTTPOfListener(ln net.Listener) string {
 
 	var goodIP string
 	var privateIP string
-	ForeachInterfaceAddress(func(i Interface, ip netaddr.IP) {
+	ForeachInterfaceAddress(func(i Interface, pfx netaddr.IPPrefix) {
+		ip := pfx.IP
 		if isPrivateIP(ip) {
 			if privateIP == "" {
 				privateIP = ip.String()
@@ -352,7 +420,8 @@ func LikelyHomeRouterIP() (gateway, myIP netaddr.IP, ok bool) {
 	if !ok {
 		return
 	}
-	ForeachInterfaceAddress(func(i Interface, ip netaddr.IP) {
+	ForeachInterfaceAddress(func(i Interface, pfx netaddr.IPPrefix) {
+		ip := pfx.IP
 		if !i.IsUp() || ip.IsZero() || !myIP.IsZero() {
 			return
 		}
@@ -392,14 +461,23 @@ var (
 	v6Global1     = mustCIDR("2000::/3")
 )
 
-func allLoopbackIPs(ips []netaddr.IP) bool {
-	if len(ips) == 0 {
-		return false
-	}
-	for _, ip := range ips {
-		if !ip.IsLoopback() {
-			return false
+// anyInterestingIP reports whether pfxs contains any IP that matches
+// isInterestingIP.
+func anyInterestingIP(pfxs []netaddr.IPPrefix) bool {
+	for _, pfx := range pfxs {
+		if isInterestingIP(pfx.IP) {
+			return true
 		}
 	}
+	return false
+}
+
+// isInterestingIP reports whether ip is an interesting IP that we
+// should log in interfaces.State logging. We don't need to show
+// localhost or link-local addresses.
+func isInterestingIP(ip netaddr.IP) bool {
+	if ip.IsLoopback() || ip.IsLinkLocalUnicast() {
+		return false
+	}
 	return true
 }

net/interfaces/interfaces_darwin_cgo.go

@@ -15,7 +15,7 @@ package interfaces
 
 // privateGatewayIPFromRoute returns the private gateway ip address from rtm, if it exists.
 // Otherwise, it returns 0.
-int privateGatewayIPFromRoute(struct rt_msghdr2 *rtm)
+uint32_t privateGatewayIPFromRoute(struct rt_msghdr2 *rtm)
 {
     // sockaddrs are after the message header
     struct sockaddr* dst_sa = (struct sockaddr *)(rtm + 1);
@@ -38,7 +38,7 @@ int privateGatewayIPFromRoute(struct rt_msghdr2 *rtm)
         return 0; // gateway not IPv4
 
     struct sockaddr_in* gateway_si= (struct sockaddr_in *)gateway_sa;
-    int ip;
+    uint32_t ip;
     ip = gateway_si->sin_addr.s_addr;
 
     unsigned char a, b;
@@ -62,7 +62,7 @@ int privateGatewayIPFromRoute(struct rt_msghdr2 *rtm)
 // If no private gateway IP address was found, it returns 0.
 // On an error, it returns an error code in (0, 255].
 // Any private gateway IP address is > 255.
-int privateGatewayIP()
+uint32_t privateGatewayIP()
 {
     size_t needed;
     int mib[6];
@@ -90,7 +90,7 @@ int privateGatewayIP()
 	struct rt_msghdr2 *rtm;
     for (next = buf; next < lim; next += rtm->rtm_msglen) {
         rtm = (struct rt_msghdr2 *)next;
-		int ip;
+        uint32_t ip;
         ip = privateGatewayIPFromRoute(rtm);
         if (ip) {
             free(buf);

net/interfaces/interfaces_darwin_tailscaled.go

@@ -0,0 +1,81 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin,!redo,!ios
+// (Exclude redo, because we don't want this code in the App Store
+// version's sandbox, where it won't work, and also don't want it on
+// iOS. This is just for utun-using non-sandboxed cmd/tailscaled on macOS.
+
+package interfaces
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"syscall"
+
+	"golang.org/x/net/route"
+)
+
+func DefaultRouteInterface() (string, error) {
+	idx, err := DefaultRouteInterfaceIndex()
+	if err != nil {
+		return "", err
+	}
+	iface, err := net.InterfaceByIndex(idx)
+	if err != nil {
+		return "", err
+	}
+	return iface.Name, nil
+}
+
+func DefaultRouteInterfaceIndex() (int, error) {
+	// $ netstat -nr
+	// Routing tables
+	// Internet:
+	// Destination        Gateway            Flags        Netif Expire
+	// default            10.0.0.1           UGSc           en0         <-- want this one
+	// default            10.0.0.1           UGScI          en1
+
+	// From man netstat:
+	// U       RTF_UP           Route usable
+	// G       RTF_GATEWAY      Destination requires forwarding by intermediary
+	// S       RTF_STATIC       Manually added
+	// c       RTF_PRCLONING    Protocol-specified generate new routes on use
+	// I       RTF_IFSCOPE      Route is associated with an interface scope
+
+	rib, err := route.FetchRIB(syscall.AF_UNSPEC, syscall.NET_RT_DUMP2, 0)
+	if err != nil {
+		return 0, fmt.Errorf("route.FetchRIB: %w", err)
+	}
+	msgs, err := route.ParseRIB(syscall.NET_RT_IFLIST2, rib)
+	if err != nil {
+		return 0, fmt.Errorf("route.ParseRIB: %w", err)
+	}
+	indexSeen := map[int]int{} // index => count
+	for _, m := range msgs {
+		rm, ok := m.(*route.RouteMessage)
+		if !ok {
+			continue
+		}
+		const RTF_GATEWAY = 0x2
+		const RTF_IFSCOPE = 0x1000000
+		if rm.Flags&RTF_GATEWAY == 0 {
+			continue
+		}
+		if rm.Flags&RTF_IFSCOPE != 0 {
+			continue
+		}
+		indexSeen[rm.Index]++
+	}
+	if len(indexSeen) == 0 {
+		return 0, errors.New("no gateway index found")
+	}
+	if len(indexSeen) == 1 {
+		for idx := range indexSeen {
+			return idx, nil
+		}
+	}
+	return 0, fmt.Errorf("ambiguous gateway interfaces found: %v", indexSeen)
+}

net/interfaces/interfaces_default_route_test.go

@@ -0,0 +1,17 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux darwin,!redo
+
+package interfaces
+
+import "testing"
+
+func TestDefaultRouteInterface(t *testing.T) {
+	v, err := DefaultRouteInterface()
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("got %q", v)
+}

net/interfaces/interfaces_defaultrouteif_todo.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !linux,!windows
+// +build !linux,!windows,!darwin darwin,redo
 
 package interfaces
 

net/interfaces/interfaces_test.go

@@ -5,30 +5,9 @@
 package interfaces
 
 import (
-	"net"
 	"testing"
 )
 
-func TestIsTailscaleIP(t *testing.T) {
-	tests := []struct {
-		ip   string
-		want bool
-	}{
-		{"100.81.251.94", true},
-		{"8.8.8.8", false},
-	}
-	for _, tt := range tests {
-		ip := net.ParseIP(tt.ip)
-		if ip == nil {
-			t.Fatalf("failed to parse IP %q", tt.ip)
-		}
-		got := IsTailscaleIP(ip)
-		if got != tt.want {
-			t.Errorf("F(%q) = %v; want %v", tt.ip, got, tt.want)
-		}
-	}
-}
-
 func TestGetState(t *testing.T) {
 	st, err := GetState()
 	if err != nil {

net/netcheck/netcheck.go

@@ -8,9 +8,7 @@ package netcheck
 import (
 	"bufio"
 	"context"
-	"crypto/rand"
 	"crypto/tls"
-	"encoding/binary"
 	"errors"
 	"fmt"
 	"io"
@@ -25,11 +23,11 @@ import (
 	"time"
 
 	"github.com/tcnksm/go-httpstat"
-	"go4.org/mem"
 	"inet.af/netaddr"
 	"tailscale.com/derp/derphttp"
 	"tailscale.com/net/interfaces"
 	"tailscale.com/net/netns"
+	"tailscale.com/net/portmapper"
 	"tailscale.com/net/stun"
 	"tailscale.com/syncs"
 	"tailscale.com/tailcfg"
@@ -68,12 +66,6 @@ const (
 	// more aggressive than defaultActiveRetransmitTime. A few extra
 	// packets at startup is fine.
 	defaultInitialRetransmitTime = 100 * time.Millisecond
-	// portMapServiceProbeTimeout is the time we wait for port mapping
-	// services (UPnP, NAT-PMP, PCP) to respond before we give up and
-	// decide that they're not there. Since these services are on the
-	// same LAN as this machine and a single L3 hop away, we don't
-	// give them much time to respond.
-	portMapServiceProbeTimeout = 100 * time.Millisecond
 )
 
 type Report struct {
@@ -160,6 +152,10 @@ type Client struct {
 	// It defaults to ":0".
 	UDPBindAddr string
 
+	// PortMapper, if non-nil, is used for portmap queries.
+	// If nil, portmap discovery is not done.
+	PortMapper *portmapper.Client // lazily initialized on first use
+
 	mu       sync.Mutex            // guards following
 	nextFull bool                  // do a full region scan, even if last != nil
 	prev     map[time.Time]*Report // some previous reports
@@ -219,8 +215,8 @@ func (c *Client) handleHairSTUNLocked(pkt []byte, src netaddr.IPPort) bool {
 // (non-incremental) probe of all DERP regions.
 func (c *Client) MakeNextReportFull() {
 	c.mu.Lock()
+	defer c.mu.Unlock()
 	c.nextFull = true
-	c.mu.Unlock()
 }
 
 func (c *Client) ReceiveSTUNPacket(pkt []byte, src netaddr.IPPort) {
@@ -680,104 +676,20 @@ func (rs *reportState) setOptBool(b *opt.Bool, v bool) {
 
 func (rs *reportState) probePortMapServices() {
 	defer rs.waitPortMap.Done()
-	gw, myIP, ok := interfaces.LikelyHomeRouterIP()
-	if !ok {
-		return
-	}
 
 	rs.setOptBool(&rs.report.UPnP, false)
 	rs.setOptBool(&rs.report.PMP, false)
 	rs.setOptBool(&rs.report.PCP, false)
 
-	port1900 := netaddr.IPPort{IP: gw, Port: 1900}.UDPAddr()
-	port5351 := netaddr.IPPort{IP: gw, Port: 5351}.UDPAddr()
-
-	rs.c.logf("[v1] probePortMapServices: me %v -> gw %v", myIP, gw)
-
-	// Create a UDP4 socket used just for querying for UPnP, NAT-PMP, and PCP.
-	uc, err := netns.Listener().ListenPacket(context.Background(), "udp4", ":0")
+	res, err := rs.c.PortMapper.Probe(context.Background())
 	if err != nil {
 		rs.c.logf("probePortMapServices: %v", err)
 		return
 	}
-	defer uc.Close()
-	tempPort := uc.LocalAddr().(*net.UDPAddr).Port
-	uc.SetReadDeadline(time.Now().Add(portMapServiceProbeTimeout))
 
-	// Send request packets for all three protocols.
-	uc.WriteTo(uPnPPacket, port1900)
-	uc.WriteTo(pmpPacket, port5351)
-	uc.WriteTo(pcpPacket(myIP, tempPort, false), port5351)
-
-	res := make([]byte, 1500)
-	sentPCPDelete := false
-	for {
-		n, addr, err := uc.ReadFrom(res)
-		if err != nil {
-			return
-		}
-		switch addr.(*net.UDPAddr).Port {
-		case 1900:
-			if mem.Contains(mem.B(res[:n]), mem.S(":InternetGatewayDevice:")) {
-				rs.setOptBool(&rs.report.UPnP, true)
-			}
-		case 5351:
-			if n == 12 && res[0] == 0x00 { // right length and version 0
-				rs.setOptBool(&rs.report.PMP, true)
-			}
-			if n == 60 && res[0] == 0x02 { // right length and version 2
-				rs.setOptBool(&rs.report.PCP, true)
-
-				if !sentPCPDelete {
-					sentPCPDelete = true
-					// And now delete the mapping.
-					// (PCP is the only protocol of the three that requires
-					// we cause a side effect to detect whether it's present,
-					// so we need to redo that side effect now.)
-					uc.WriteTo(pcpPacket(myIP, tempPort, true), port5351)
-				}
-			}
-		}
-	}
-}
-
-var pmpPacket = []byte{0, 0} // version 0, opcode 0 = "Public address request"
-
-var uPnPPacket = []byte("M-SEARCH * HTTP/1.1\r\n" +
-	"HOST: 239.255.255.250:1900\r\n" +
-	"ST: ssdp:all\r\n" +
-	"MAN: \"ssdp:discover\"\r\n" +
-	"MX: 2\r\n\r\n")
-
-var v4unspec, _ = netaddr.ParseIP("0.0.0.0")
-
-// pcpPacket generates a PCP packet with a MAP opcode.
-func pcpPacket(myIP netaddr.IP, mapToLocalPort int, delete bool) []byte {
-	const udpProtoNumber = 17
-	lifetimeSeconds := uint32(1)
-	if delete {
-		lifetimeSeconds = 0
-	}
-	const opMap = 1
-
-	// 24 byte header + 36 byte map opcode
-	pkt := make([]byte, (32+32+128)/8+(96+8+24+16+16+128)/8)
-
-	// The header (https://tools.ietf.org/html/rfc6887#section-7.1)
-	pkt[0] = 2 // version
-	pkt[1] = opMap
-	binary.BigEndian.PutUint32(pkt[4:8], lifetimeSeconds)
-	myIP16 := myIP.As16()
-	copy(pkt[8:], myIP16[:])
-
-	// The map opcode body (https://tools.ietf.org/html/rfc6887#section-11.1)
-	mapOp := pkt[24:]
-	rand.Read(mapOp[:12]) // 96 bit mappping nonce
-	mapOp[12] = udpProtoNumber
-	binary.BigEndian.PutUint16(mapOp[16:], uint16(mapToLocalPort))
-	v4unspec16 := v4unspec.As16()
-	copy(mapOp[20:], v4unspec16[:])
-	return pkt
+	rs.setOptBool(&rs.report.UPnP, res.UPnP)
+	rs.setOptBool(&rs.report.PMP, res.PMP)
+	rs.setOptBool(&rs.report.PCP, res.PCP)
 }
 
 func newReport() *Report {
@@ -854,7 +766,7 @@ func (c *Client) GetReport(ctx context.Context, dm *tailcfg.DERPMap) (*Report, e
 	}
 	defer rs.pc4Hair.Close()
 
-	if !c.SkipExternalNetwork {
+	if !c.SkipExternalNetwork && c.PortMapper != nil {
 		rs.waitPortMap.Add(1)
 		go rs.probePortMapServices()
 	}
@@ -927,7 +839,7 @@ func (c *Client) GetReport(ctx context.Context, dm *tailcfg.DERPMap) (*Report, e
 
 	rs.waitHairCheck(ctx)
 	c.vlogf("hairCheck done")
-	if !c.SkipExternalNetwork {
+	if !c.SkipExternalNetwork && c.PortMapper != nil {
 		rs.waitPortMap.Wait()
 		c.vlogf("portMap done")
 	}

net/netns/netns_darwin_tailscaled.go

@@ -0,0 +1,52 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin,!redo
+
+package netns
+
+import (
+	"fmt"
+	"log"
+	"strings"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+	"tailscale.com/net/interfaces"
+)
+
+// control marks c as necessary to dial in a separate network namespace.
+//
+// It's intentionally the same signature as net.Dialer.Control
+// and net.ListenConfig.Control.
+func control(network, address string, c syscall.RawConn) error {
+	if strings.HasPrefix(address, "127.") || address == "::1" {
+		// Don't bind to an interface for localhost connections.
+		return nil
+	}
+	idx, err := interfaces.DefaultRouteInterfaceIndex()
+	if err != nil {
+		log.Printf("netns: DefaultRouteInterfaceIndex: %v", err)
+		return nil
+	}
+	v6 := strings.Contains(address, "]:") || strings.HasSuffix(network, "6") // hacky test for v6
+	proto := unix.IPPROTO_IP
+	opt := unix.IP_BOUND_IF
+	if v6 {
+		proto = unix.IPPROTO_IPV6
+		opt = unix.IPV6_BOUND_IF
+	}
+
+	var sockErr error
+	err = c.Control(func(fd uintptr) {
+		sockErr = unix.SetsockoptInt(int(fd), proto, opt, idx)
+	})
+	if err != nil {
+		return fmt.Errorf("RawConn.Control on %T: %w", c, err)
+	}
+	if sockErr != nil {
+		log.Printf("netns: control(%q, %q), v6=%v, index=%v: %v", network, address, v6, idx, sockErr)
+	}
+	return sockErr
+}

net/netns/netns_default.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !linux,!windows
+// +build !linux,!windows,!darwin darwin,redo
 
 package netns
 

net/netns/netns_test.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package netns contains the common code for using the Go net package
+// in a logical "network namespace" to avoid routing loops where
+// Tailscale-created packets would otherwise loop back through
+// Tailscale routes.
+//
+// Despite the name netns, the exact mechanism used differs by
+// operating system, and perhaps even by version of the OS.
+//
+// The netns package also handles connecting via SOCKS proxies when
+// configured by the environment.
+package netns
+
+import (
+	"flag"
+	"testing"
+)
+
+var extNetwork = flag.Bool("use-external-network", false, "use the external network in tests")
+
+func TestDial(t *testing.T) {
+	if !*extNetwork {
+		t.Skip("skipping test without --use-external-network")
+	}
+	d := NewDialer()
+	c, err := d.Dial("tcp", "google.com:80")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+	t.Logf("got addr %v", c.RemoteAddr())
+
+	c, err = d.Dial("tcp4", "google.com:80")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+	t.Logf("got addr %v", c.RemoteAddr())
+}

net/packet/tsmp.go

@@ -23,12 +23,14 @@ import (
 // Tailscale node has rejected the connection from another. Unlike a
 // TCP RST, this includes a reason.
 //
-// On the wire, after the IP header, it's currently 7 bytes:
+// On the wire, after the IP header, it's currently 7 or 8 bytes:
 //     * '!'
 //     * IPProto byte (IANA protocol number: TCP or UDP)
 //     * 'A' or 'S' (RejectedDueToACLs, RejectedDueToShieldsUp)
 //     * srcPort big endian uint16
 //     * dstPort big endian uint16
+//     * [optional] byte of flag bits:
+//          lowest bit (0x1): MaybeBroken
 //
 // In the future it might also accept 16 byte IP flow src/dst IPs
 // after the header, if they're different than the IP-level ones.
@@ -39,8 +41,21 @@ type TailscaleRejectedHeader struct {
 	Dst    netaddr.IPPort        // rejected flow's dst
 	Proto  IPProto               // proto that was rejected (TCP or UDP)
 	Reason TailscaleRejectReason // why the connection was rejected
+
+	// MaybeBroken is whether the rejection is non-terminal (the
+	// client should not fail immediately). This is sent by a
+	// target when it's not sure whether it's totally broken, but
+	// it might be. For example, the target tailscaled might think
+	// its host firewall or IP forwarding aren't configured
+	// properly, but tailscaled might be wrong (not having enough
+	// visibility into what the OS is doing). When true, the
+	// message is simply an FYI as a potential reason to use for
+	// later when the pendopen connection tracking timer expires.
+	MaybeBroken bool
 }
 
+const rejectFlagBitMaybeBroken = 0x1
+
 func (rh TailscaleRejectedHeader) Flow() flowtrack.Tuple {
 	return flowtrack.Tuple{Src: rh.Src, Dst: rh.Dst}
 }
@@ -52,14 +67,32 @@ func (rh TailscaleRejectedHeader) String() string {
 type TSMPType uint8
 
 const (
+	// TSMPTypeRejectedConn is the type byte for a TailscaleRejectedHeader.
 	TSMPTypeRejectedConn TSMPType = '!'
 )
 
 type TailscaleRejectReason byte
 
+// IsZero reports whether r is the zero value, representing no rejection.
+func (r TailscaleRejectReason) IsZero() bool { return r == TailscaleRejectReasonNone }
+
 const (
-	RejectedDueToACLs      TailscaleRejectReason = 'A'
+	// TailscaleRejectReasonNone is the TailscaleRejectReason zero value.
+	TailscaleRejectReasonNone TailscaleRejectReason = 0
+
+	// RejectedDueToACLs means that the host rejected the connection due to ACLs.
+	RejectedDueToACLs TailscaleRejectReason = 'A'
+
+	// RejectedDueToShieldsUp means that the host rejected the connection due to shields being up.
 	RejectedDueToShieldsUp TailscaleRejectReason = 'S'
+
+	// RejectedDueToIPForwarding means that the relay node's IP
+	// forwarding is disabled.
+	RejectedDueToIPForwarding TailscaleRejectReason = 'F'
+
+	// RejectedDueToHostFirewall means that the target host's
+	// firewall is blocking the traffic.
+	RejectedDueToHostFirewall TailscaleRejectReason = 'W'
 )
 
 func (r TailscaleRejectReason) String() string {
@@ -68,22 +101,32 @@ func (r TailscaleRejectReason) String() string {
 		return "acl"
 	case RejectedDueToShieldsUp:
 		return "shields"
+	case RejectedDueToIPForwarding:
+		return "host-ip-forwarding-unavailable"
+	case RejectedDueToHostFirewall:
+		return "host-firewall"
 	}
 	return fmt.Sprintf("0x%02x", byte(r))
 }
 
+func (h TailscaleRejectedHeader) hasFlags() bool {
+	return h.MaybeBroken // the only one currently
+}
+
 func (h TailscaleRejectedHeader) Len() int {
-	var ipHeaderLen int
-	if h.IPSrc.Is4() {
-		ipHeaderLen = ip4HeaderLength
-	} else if h.IPSrc.Is6() {
-		ipHeaderLen = ip6HeaderLength
-	}
-	return ipHeaderLen +
-		1 + // TSMPType byte
+	v := 1 + // TSMPType byte
 		1 + // IPProto byte
 		1 + // TailscaleRejectReason byte
 		2*2 // 2 uint16 ports
+	if h.IPSrc.Is4() {
+		v += ip4HeaderLength
+	} else if h.IPSrc.Is6() {
+		v += ip6HeaderLength
+	}
+	if h.hasFlags() {
+		v++
+	}
+	return v
 }
 
 func (h TailscaleRejectedHeader) Marshal(buf []byte) error {
@@ -117,6 +160,14 @@ func (h TailscaleRejectedHeader) Marshal(buf []byte) error {
 	buf[2] = byte(h.Reason)
 	binary.BigEndian.PutUint16(buf[3:5], h.Src.Port)
 	binary.BigEndian.PutUint16(buf[5:7], h.Dst.Port)
+
+	if h.hasFlags() {
+		var flags byte
+		if h.MaybeBroken {
+			flags |= rejectFlagBitMaybeBroken
+		}
+		buf[7] = flags
+	}
 	return nil
 }
 
@@ -129,12 +180,17 @@ func (pp *Parsed) AsTailscaleRejectedHeader() (h TailscaleRejectedHeader, ok boo
 	if len(p) < 7 || p[0] != byte(TSMPTypeRejectedConn) {
 		return
 	}
-	return TailscaleRejectedHeader{
+	h = TailscaleRejectedHeader{
 		Proto:  IPProto(p[1]),
 		Reason: TailscaleRejectReason(p[2]),
 		IPSrc:  pp.Src.IP,
 		IPDst:  pp.Dst.IP,
 		Src:    netaddr.IPPort{IP: pp.Dst.IP, Port: binary.BigEndian.Uint16(p[3:5])},
 		Dst:    netaddr.IPPort{IP: pp.Src.IP, Port: binary.BigEndian.Uint16(p[5:7])},
-	}, true
+	}
+	if len(p) > 7 {
+		flags := p[7]
+		h.MaybeBroken = (flags & rejectFlagBitMaybeBroken) != 0
+	}
+	return h, true
 }

net/packet/tsmp_test.go

@@ -37,6 +37,18 @@ func TestTailscaleRejectedHeader(t *testing.T) {
 			},
 			wantStr: "TSMP-reject-flow{UDP [1::1]:567 > [2::2]:443}: shields",
 		},
+		{
+			h: TailscaleRejectedHeader{
+				IPSrc:       netaddr.MustParseIP("2::2"),
+				IPDst:       netaddr.MustParseIP("1::1"),
+				Src:         netaddr.MustParseIPPort("[1::1]:567"),
+				Dst:         netaddr.MustParseIPPort("[2::2]:443"),
+				Proto:       UDP,
+				Reason:      RejectedDueToIPForwarding,
+				MaybeBroken: true,
+			},
+			wantStr: "TSMP-reject-flow{UDP [1::1]:567 > [2::2]:443}: host-ip-forwarding-unavailable",
+		},
 	}
 	for i, tt := range tests {
 		gotStr := tt.h.String()

net/portmapper/portmapper.go

@@ -0,0 +1,611 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package portmapper is a UDP port mapping client. It currently only does
+// NAT-PMP, but will likely do UPnP and perhaps PCP later.
+package portmapper
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"sync"
+	"time"
+
+	"go4.org/mem"
+	"inet.af/netaddr"
+	"tailscale.com/net/interfaces"
+	"tailscale.com/net/netns"
+	"tailscale.com/types/logger"
+)
+
+// References:
+//
+// NAT-PMP: https://tools.ietf.org/html/rfc6886
+// PCP: https://tools.ietf.org/html/rfc6887
+
+// portMapServiceTimeout is the time we wait for port mapping
+// services (UPnP, NAT-PMP, PCP) to respond before we give up and
+// decide that they're not there. Since these services are on the
+// same LAN as this machine and a single L3 hop away, we don't
+// give them much time to respond.
+const portMapServiceTimeout = 250 * time.Millisecond
+
+// trustServiceStillAvailableDuration is how often we re-verify a port
+// mapping service is available.
+const trustServiceStillAvailableDuration = 10 * time.Minute
+
+// Client is a port mapping client.
+type Client struct {
+	logf logger.Logf
+
+	mu sync.Mutex // guards following, and all fields thereof
+
+	lastMyIP netaddr.IP
+	lastGW   netaddr.IP
+	closed   bool
+
+	lastProbe time.Time
+
+	pmpPubIP     netaddr.IP // non-zero if known
+	pmpPubIPTime time.Time  // time pmpPubIP last verified
+	pmpLastEpoch uint32
+
+	pcpSawTime  time.Time // time we last saw PCP was available
+	uPnPSawTime time.Time // time we last saw UPnP was available
+
+	localPort  uint16
+	pmpMapping *pmpMapping // non-nil if we have a PMP mapping
+}
+
+// pmpMapping is an already-created PMP mapping.
+//
+// All fields are immutable once created.
+type pmpMapping struct {
+	gw       netaddr.IP
+	external netaddr.IPPort
+	internal netaddr.IPPort
+	useUntil time.Time // the mapping's lifetime minus renewal interval
+	epoch    uint32
+}
+
+// externalValid reports whether m.external is valid, with both its IP and Port populated.
+func (m *pmpMapping) externalValid() bool {
+	return !m.external.IP.IsZero() && m.external.Port != 0
+}
+
+// release does a best effort fire-and-forget release of the PMP mapping m.
+func (m *pmpMapping) release() {
+	uc, err := netns.Listener().ListenPacket(context.Background(), "udp4", ":0")
+	if err != nil {
+		return
+	}
+	defer uc.Close()
+	pkt := buildPMPRequestMappingPacket(m.internal.Port, m.external.Port, pmpMapLifetimeDelete)
+	uc.WriteTo(pkt, netaddr.IPPort{IP: m.gw, Port: pmpPort}.UDPAddr())
+}
+
+// NewClient returns a new portmapping client.
+func NewClient(logf logger.Logf) *Client {
+	return &Client{
+		logf: logf,
+	}
+}
+
+// NoteNetworkDown should be called when the network has transitioned to a down state.
+// It's too late to release port mappings at this point (the user might've just turned off
+// their wifi), but we can make sure we invalidate mappings for later when the network
+// comes back.
+func (c *Client) NoteNetworkDown() {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.invalidateMappingsLocked(false)
+}
+
+func (c *Client) Close() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.closed {
+		return nil
+	}
+	c.closed = true
+	c.invalidateMappingsLocked(true)
+	// TODO: close some future ever-listening UDP socket(s),
+	// waiting for multicast announcements from router.
+	return nil
+}
+
+// SetLocalPort updates the local port number to which we want to port
+// map UDP traffic.
+func (c *Client) SetLocalPort(localPort uint16) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.localPort == localPort {
+		return
+	}
+	c.localPort = localPort
+	c.invalidateMappingsLocked(true)
+}
+
+func (c *Client) gatewayAndSelfIP() (gw, myIP netaddr.IP, ok bool) {
+	gw, myIP, ok = interfaces.LikelyHomeRouterIP()
+	if !ok {
+		gw = netaddr.IP{}
+		myIP = netaddr.IP{}
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if gw != c.lastGW || myIP != c.lastMyIP || !ok {
+		c.lastMyIP = myIP
+		c.lastGW = gw
+		c.invalidateMappingsLocked(true)
+	}
+	return
+}
+
+func (c *Client) invalidateMappingsLocked(releaseOld bool) {
+	if c.pmpMapping != nil {
+		if releaseOld {
+			c.pmpMapping.release()
+		}
+		c.pmpMapping = nil
+	}
+	c.pmpPubIP = netaddr.IP{}
+	c.pmpPubIPTime = time.Time{}
+	c.pcpSawTime = time.Time{}
+	c.uPnPSawTime = time.Time{}
+}
+
+func (c *Client) sawPMPRecently() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.sawPMPRecentlyLocked()
+}
+
+func (c *Client) sawPMPRecentlyLocked() bool {
+	return !c.pmpPubIP.IsZero() && c.pmpPubIPTime.After(time.Now().Add(-trustServiceStillAvailableDuration))
+}
+
+func (c *Client) sawPCPRecently() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.pcpSawTime.After(time.Now().Add(-trustServiceStillAvailableDuration))
+}
+
+func (c *Client) sawUPnPRecently() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.uPnPSawTime.After(time.Now().Add(-trustServiceStillAvailableDuration))
+}
+
+// closeCloserOnContextDone starts a new goroutine to call c.Close
+// if/when ctx becomes done.
+// To stop the goroutine, call the returned stop func.
+func closeCloserOnContextDone(ctx context.Context, c io.Closer) (stop func()) {
+	// Close uc on ctx being done.
+	ctxDone := ctx.Done()
+	if ctxDone == nil {
+		return func() {}
+	}
+	stopWaitDone := make(chan struct{})
+	go func() {
+		select {
+		case <-stopWaitDone:
+		case <-ctxDone:
+			c.Close()
+		}
+	}()
+	return func() { close(stopWaitDone) }
+}
+
+// NoMappingError is returned by CreateOrGetMapping when no NAT
+// mapping could be returned.
+type NoMappingError struct {
+	err error
+}
+
+func (nme NoMappingError) Unwrap() error { return nme.err }
+func (nme NoMappingError) Error() string { return fmt.Sprintf("no NAT mapping available: %v", nme.err) }
+
+// IsNoMappingError reports whether err is of type NoMappingError.
+func IsNoMappingError(err error) bool {
+	_, ok := err.(NoMappingError)
+	return ok
+}
+
+var (
+	ErrNoPortMappingServices = errors.New("no port mapping services were found")
+	ErrGatewayNotFound       = errors.New("failed to look gateway address")
+)
+
+// CreateOrGetMapping either creates a new mapping or returns a cached
+// valid one.
+//
+// If no mapping is available, the error will be of type
+// NoMappingError; see IsNoMappingError.
+func (c *Client) CreateOrGetMapping(ctx context.Context) (external netaddr.IPPort, err error) {
+	gw, myIP, ok := c.gatewayAndSelfIP()
+	if !ok {
+		return netaddr.IPPort{}, NoMappingError{ErrGatewayNotFound}
+	}
+
+	c.mu.Lock()
+	localPort := c.localPort
+	m := &pmpMapping{
+		gw:       gw,
+		internal: netaddr.IPPort{IP: myIP, Port: localPort},
+	}
+
+	// prevPort is the port we had most previously, if any. We try
+	// to ask for the same port. 0 means to give us any port.
+	var prevPort uint16
+
+	// Do we have an existing mapping that's valid?
+	now := time.Now()
+	if m := c.pmpMapping; m != nil {
+		if now.Before(m.useUntil) {
+			defer c.mu.Unlock()
+			return m.external, nil
+		}
+		// The mapping might still be valid, so just try to renew it.
+		prevPort = m.external.Port
+	}
+
+	// If we just did a Probe (e.g. via netchecker) but didn't
+	// find a PMP service, bail out early rather than probing
+	// again. Cuts down latency for most clients.
+	haveRecentPMP := c.sawPMPRecentlyLocked()
+	if haveRecentPMP {
+		m.external.IP = c.pmpPubIP
+	}
+	if c.lastProbe.After(now.Add(-5*time.Second)) && !haveRecentPMP {
+		c.mu.Unlock()
+		return netaddr.IPPort{}, NoMappingError{ErrNoPortMappingServices}
+	}
+
+	c.mu.Unlock()
+
+	uc, err := netns.Listener().ListenPacket(ctx, "udp4", ":0")
+	if err != nil {
+		return netaddr.IPPort{}, err
+	}
+	defer uc.Close()
+
+	uc.SetReadDeadline(time.Now().Add(portMapServiceTimeout))
+	defer closeCloserOnContextDone(ctx, uc)()
+
+	pmpAddr := netaddr.IPPort{IP: gw, Port: pmpPort}
+	pmpAddru := pmpAddr.UDPAddr()
+
+	// Ask for our external address if needed.
+	if m.external.IP.IsZero() {
+		if _, err := uc.WriteTo(pmpReqExternalAddrPacket, pmpAddru); err != nil {
+			return netaddr.IPPort{}, err
+		}
+	}
+
+	// And ask for a mapping.
+	pmpReqMapping := buildPMPRequestMappingPacket(localPort, prevPort, pmpMapLifetimeSec)
+	if _, err := uc.WriteTo(pmpReqMapping, pmpAddru); err != nil {
+		return netaddr.IPPort{}, err
+	}
+
+	res := make([]byte, 1500)
+	for {
+		n, srci, err := uc.ReadFrom(res)
+		if err != nil {
+			if ctx.Err() == context.Canceled {
+				return netaddr.IPPort{}, err
+			}
+			return netaddr.IPPort{}, NoMappingError{ErrNoPortMappingServices}
+		}
+		srcu := srci.(*net.UDPAddr)
+		src, ok := netaddr.FromStdAddr(srcu.IP, srcu.Port, srcu.Zone)
+		if !ok {
+			continue
+		}
+		if src == pmpAddr {
+			pres, ok := parsePMPResponse(res[:n])
+			if !ok {
+				c.logf("unexpected PMP response: % 02x", res[:n])
+				continue
+			}
+			if pres.ResultCode != 0 {
+				return netaddr.IPPort{}, NoMappingError{fmt.Errorf("PMP response Op=0x%x,Res=0x%x", pres.OpCode, pres.ResultCode)}
+			}
+			if pres.OpCode == pmpOpReply|pmpOpMapPublicAddr {
+				m.external.IP = pres.PublicAddr
+			}
+			if pres.OpCode == pmpOpReply|pmpOpMapUDP {
+				m.external.Port = pres.ExternalPort
+				d := time.Duration(pres.MappingValidSeconds) * time.Second
+				d /= 2 // renew in half the time
+				m.useUntil = time.Now().Add(d)
+				m.epoch = pres.SecondsSinceEpoch
+			}
+		}
+
+		if m.externalValid() {
+			c.mu.Lock()
+			defer c.mu.Unlock()
+			c.pmpMapping = m
+			return m.external, nil
+		}
+	}
+}
+
+type pmpResultCode uint16
+
+// NAT-PMP constants.
+const (
+	pmpPort              = 5351
+	pmpMapLifetimeSec    = 7200 // RFC recommended 2 hour map duration
+	pmpMapLifetimeDelete = 0    // 0 second lifetime deletes
+
+	pmpOpMapPublicAddr = 0
+	pmpOpMapUDP        = 1
+	pmpOpReply         = 0x80 // OR'd into request's op code on response
+
+	pmpCodeOK                 pmpResultCode = 0
+	pmpCodeUnsupportedVersion pmpResultCode = 1
+	pmpCodeNotAuthorized      pmpResultCode = 2 // "e.g., box supports mapping, but user has turned feature off"
+	pmpCodeNetworkFailure     pmpResultCode = 3 // "e.g., NAT box itself has not obtained a DHCP lease"
+	pmpCodeOutOfResources     pmpResultCode = 4
+	pmpCodeUnsupportedOpcode  pmpResultCode = 5
+)
+
+func buildPMPRequestMappingPacket(localPort, prevPort uint16, lifetimeSec uint32) (pkt []byte) {
+	pkt = make([]byte, 12)
+
+	pkt[1] = pmpOpMapUDP
+	binary.BigEndian.PutUint16(pkt[4:], localPort)
+	binary.BigEndian.PutUint16(pkt[6:], prevPort)
+	binary.BigEndian.PutUint32(pkt[8:], lifetimeSec)
+
+	return pkt
+}
+
+type pmpResponse struct {
+	OpCode            uint8
+	ResultCode        pmpResultCode
+	SecondsSinceEpoch uint32
+
+	// For Map ops:
+	MappingValidSeconds uint32
+	InternalPort        uint16
+	ExternalPort        uint16
+
+	// For public addr ops:
+	PublicAddr netaddr.IP
+}
+
+func parsePMPResponse(pkt []byte) (res pmpResponse, ok bool) {
+	if len(pkt) < 12 {
+		return
+	}
+	ver := pkt[0]
+	if ver != 0 {
+		return
+	}
+	res.OpCode = pkt[1]
+	res.ResultCode = pmpResultCode(binary.BigEndian.Uint16(pkt[2:]))
+	res.SecondsSinceEpoch = binary.BigEndian.Uint32(pkt[4:])
+
+	if res.OpCode == pmpOpReply|pmpOpMapUDP {
+		if len(pkt) != 16 {
+			return res, false
+		}
+		res.InternalPort = binary.BigEndian.Uint16(pkt[8:])
+		res.ExternalPort = binary.BigEndian.Uint16(pkt[10:])
+		res.MappingValidSeconds = binary.BigEndian.Uint32(pkt[12:])
+	}
+
+	if res.OpCode == pmpOpReply|pmpOpMapPublicAddr {
+		if len(pkt) != 12 {
+			return res, false
+		}
+		res.PublicAddr = netaddr.IPv4(pkt[8], pkt[9], pkt[10], pkt[11])
+	}
+
+	return res, true
+}
+
+type ProbeResult struct {
+	PCP  bool
+	PMP  bool
+	UPnP bool
+}
+
+// Probe returns a summary of which port mapping services are
+// available on the network.
+//
+// If a probe has run recently and there haven't been any network changes since,
+// the returned result might be server from the Client's cache, without
+// sending any network traffic.
+func (c *Client) Probe(ctx context.Context) (res ProbeResult, err error) {
+	gw, myIP, ok := c.gatewayAndSelfIP()
+	if !ok {
+		return res, ErrGatewayNotFound
+	}
+	defer func() {
+		if err == nil {
+			c.mu.Lock()
+			defer c.mu.Unlock()
+			c.lastProbe = time.Now()
+		}
+	}()
+
+	uc, err := netns.Listener().ListenPacket(context.Background(), "udp4", ":0")
+	if err != nil {
+		c.logf("ProbePCP: %v", err)
+		return res, err
+	}
+	defer uc.Close()
+	ctx, cancel := context.WithTimeout(ctx, 250*time.Millisecond)
+	defer cancel()
+	defer closeCloserOnContextDone(ctx, uc)()
+
+	pcpAddr := netaddr.IPPort{IP: gw, Port: pcpPort}.UDPAddr()
+	pmpAddr := netaddr.IPPort{IP: gw, Port: pmpPort}.UDPAddr()
+	upnpAddr := netaddr.IPPort{IP: gw, Port: upnpPort}.UDPAddr()
+
+	// Don't send probes to services that we recently learned (for
+	// the same gw/myIP) are available. See
+	// https://github.com/tailscale/tailscale/issues/1001
+	if c.sawPMPRecently() {
+		res.PMP = true
+	} else {
+		uc.WriteTo(pmpReqExternalAddrPacket, pmpAddr)
+	}
+	if c.sawPCPRecently() {
+		res.PCP = true
+	} else {
+		uc.WriteTo(pcpAnnounceRequest(myIP), pcpAddr)
+	}
+	if c.sawUPnPRecently() {
+		res.UPnP = true
+	} else {
+		uc.WriteTo(uPnPPacket, upnpAddr)
+	}
+
+	buf := make([]byte, 1500)
+	for {
+		if res.PCP && res.PMP && res.UPnP {
+			// Nothing more to discover.
+			return res, nil
+		}
+		n, addr, err := uc.ReadFrom(buf)
+		if err != nil {
+			if ctx.Err() == context.DeadlineExceeded {
+				err = nil
+			}
+			return res, err
+		}
+		port := addr.(*net.UDPAddr).Port
+		switch port {
+		case upnpPort:
+			if mem.Contains(mem.B(buf[:n]), mem.S(":InternetGatewayDevice:")) {
+				res.UPnP = true
+				c.mu.Lock()
+				c.uPnPSawTime = time.Now()
+				c.mu.Unlock()
+			}
+		case pcpPort: // same as pmpPort
+			if pres, ok := parsePCPResponse(buf[:n]); ok {
+				if pres.OpCode == pcpOpReply|pcpOpAnnounce && pres.ResultCode == pcpCodeOK {
+					c.logf("Got PCP response: epoch: %v", pres.Epoch)
+					res.PCP = true
+					c.mu.Lock()
+					c.pcpSawTime = time.Now()
+					c.mu.Unlock()
+					continue
+				}
+				c.logf("unexpected PCP probe response: %+v", pres)
+			}
+			if pres, ok := parsePMPResponse(buf[:n]); ok {
+				if pres.OpCode == pmpOpReply|pmpOpMapPublicAddr && pres.ResultCode == pmpCodeOK {
+					c.logf("Got PMP response; IP: %v, epoch: %v", pres.PublicAddr, pres.SecondsSinceEpoch)
+					res.PMP = true
+					c.mu.Lock()
+					c.pmpPubIP = pres.PublicAddr
+					c.pmpPubIPTime = time.Now()
+					c.pmpLastEpoch = pres.SecondsSinceEpoch
+					c.mu.Unlock()
+					continue
+				}
+				c.logf("unexpected PMP probe response: %+v", pres)
+			}
+		}
+	}
+}
+
+const (
+	pcpVersion = 2
+	pcpPort    = 5351
+
+	pcpCodeOK = 0
+
+	pcpOpReply    = 0x80 // OR'd into request's op code on response
+	pcpOpAnnounce = 0
+	pcpOpMap      = 1
+)
+
+// pcpAnnounceRequest generates a PCP packet with an ANNOUNCE opcode.
+func pcpAnnounceRequest(myIP netaddr.IP) []byte {
+	// See https://tools.ietf.org/html/rfc6887#section-7.1
+	pkt := make([]byte, 24)
+	pkt[0] = pcpVersion // version
+	pkt[1] = pcpOpAnnounce
+	myIP16 := myIP.As16()
+	copy(pkt[8:], myIP16[:])
+	return pkt
+}
+
+//lint:ignore U1000 moved this code from netcheck's old PCP probing; will be needed when we add PCP mapping
+
+// pcpMapRequest generates a PCP packet with a MAP opcode.
+func pcpMapRequest(myIP netaddr.IP, mapToLocalPort int, delete bool) []byte {
+	const udpProtoNumber = 17
+	lifetimeSeconds := uint32(1)
+	if delete {
+		lifetimeSeconds = 0
+	}
+	const opMap = 1
+
+	// 24 byte header + 36 byte map opcode
+	pkt := make([]byte, (32+32+128)/8+(96+8+24+16+16+128)/8)
+
+	// The header (https://tools.ietf.org/html/rfc6887#section-7.1)
+	pkt[0] = 2 // version
+	pkt[1] = opMap
+	binary.BigEndian.PutUint32(pkt[4:8], lifetimeSeconds)
+	myIP16 := myIP.As16()
+	copy(pkt[8:], myIP16[:])
+
+	// The map opcode body (https://tools.ietf.org/html/rfc6887#section-11.1)
+	mapOp := pkt[24:]
+	rand.Read(mapOp[:12]) // 96 bit mappping nonce
+	mapOp[12] = udpProtoNumber
+	binary.BigEndian.PutUint16(mapOp[16:], uint16(mapToLocalPort))
+	v4unspec := netaddr.MustParseIP("0.0.0.0")
+	v4unspec16 := v4unspec.As16()
+	copy(mapOp[20:], v4unspec16[:])
+	return pkt
+}
+
+type pcpResponse struct {
+	OpCode     uint8
+	ResultCode uint8
+	Lifetime   uint32
+	Epoch      uint32
+}
+
+func parsePCPResponse(b []byte) (res pcpResponse, ok bool) {
+	if len(b) < 24 || b[0] != pcpVersion {
+		return
+	}
+	res.OpCode = b[1]
+	res.ResultCode = b[3]
+	res.Lifetime = binary.BigEndian.Uint32(b[4:])
+	res.Epoch = binary.BigEndian.Uint32(b[8:])
+	return res, true
+}
+
+const (
+	upnpPort = 1900
+)
+
+var uPnPPacket = []byte("M-SEARCH * HTTP/1.1\r\n" +
+	"HOST: 239.255.255.250:1900\r\n" +
+	"ST: ssdp:all\r\n" +
+	"MAN: \"ssdp:discover\"\r\n" +
+	"MX: 2\r\n\r\n")
+
+var pmpReqExternalAddrPacket = []byte{0, 0} // version 0, opcode 0 = "Public address request"

net/portmapper/portmapper_test.go

@@ -0,0 +1,54 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package portmapper
+
+import (
+	"context"
+	"os"
+	"strconv"
+	"testing"
+	"time"
+)
+
+func TestCreateOrGetMapping(t *testing.T) {
+	if v, _ := strconv.ParseBool(os.Getenv("HIT_NETWORK")); !v {
+		t.Skip("skipping test without HIT_NETWORK=1")
+	}
+	c := NewClient(t.Logf)
+	c.SetLocalPort(1234)
+	for i := 0; i < 2; i++ {
+		if i > 0 {
+			time.Sleep(100 * time.Millisecond)
+		}
+		ext, err := c.CreateOrGetMapping(context.Background())
+		t.Logf("Got: %v, %v", ext, err)
+	}
+}
+
+func TestClientProbe(t *testing.T) {
+	if v, _ := strconv.ParseBool(os.Getenv("HIT_NETWORK")); !v {
+		t.Skip("skipping test without HIT_NETWORK=1")
+	}
+	c := NewClient(t.Logf)
+	for i := 0; i < 2; i++ {
+		if i > 0 {
+			time.Sleep(100 * time.Millisecond)
+		}
+		res, err := c.Probe(context.Background())
+		t.Logf("Got: %+v, %v", res, err)
+	}
+}
+
+func TestClientProbeThenMap(t *testing.T) {
+	if v, _ := strconv.ParseBool(os.Getenv("HIT_NETWORK")); !v {
+		t.Skip("skipping test without HIT_NETWORK=1")
+	}
+	c := NewClient(t.Logf)
+	c.SetLocalPort(1234)
+	res, err := c.Probe(context.Background())
+	t.Logf("Probe: %+v, %v", res, err)
+	ext, err := c.CreateOrGetMapping(context.Background())
+	t.Logf("CreateOrGetMapping: %v, %v", ext, err)
+}

net/socks5/socks5.go

@@ -0,0 +1,364 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package socks5 is a SOCKS5 server implementation
+// for userspace networking in Tailscale.
+package socks5
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"strconv"
+	"time"
+
+	"tailscale.com/types/logger"
+)
+
+const (
+	noAuthRequired   byte = 0
+	noAcceptableAuth byte = 255
+
+	// socks5Version is the byte that represents the SOCKS version
+	// in requests.
+	socks5Version byte = 5
+)
+
+// commandType are the bytes sent in SOCKS5 packets
+// that represent the kind of connection the client needs.
+type commandType byte
+
+// The set of valid SOCKS5 commans as described in RFC 1928.
+const (
+	connect      commandType = 1
+	bind         commandType = 2
+	udpAssociate commandType = 3
+)
+
+// addrType are the bytes sent in SOCKS5 packets
+// that represent particular address types.
+type addrType byte
+
+// The set of valid SOCKS5 address types as defined in RFC 1928.
+const (
+	ipv4       addrType = 1
+	domainName addrType = 3
+	ipv6       addrType = 4
+)
+
+// replyCode are the bytes sent in SOCKS5 packets
+// that represent replies from the server to a client
+// request.
+type replyCode byte
+
+// The set of valid SOCKS5 reply types as per the RFC 1928.
+const (
+	success              replyCode = 0
+	generalFailure       replyCode = 1
+	connectionNotAllowed replyCode = 2
+	networkUnreachable   replyCode = 3
+	hostUnreachable      replyCode = 4
+	connectionRefused    replyCode = 5
+	ttlExpired           replyCode = 6
+	commandNotSupported  replyCode = 7
+	addrTypeNotSupported replyCode = 8
+)
+
+// Server is a SOCKS5 proxy server.
+type Server struct {
+	// Logf optionally specifies the logger to use.
+	// If nil, the standard logger is used.
+	Logf logger.Logf
+
+	// Dialer optionally specifies the dialer to use for outgoing connections.
+	// If nil, the net package's standard dialer is used.
+	Dialer func(ctx context.Context, network, addr string) (net.Conn, error)
+}
+
+func (s *Server) dial(ctx context.Context, network, addr string) (net.Conn, error) {
+	dial := s.Dialer
+	if dial == nil {
+		dialer := &net.Dialer{}
+		dial = dialer.DialContext
+	}
+	return dial(ctx, network, addr)
+}
+
+func (s *Server) logf(format string, args ...interface{}) {
+	logf := s.Logf
+	if logf == nil {
+		logf = log.Printf
+	}
+	logf(format, args...)
+}
+
+// Serve accepts and handles incoming connections on the given listener.
+func (s *Server) Serve(l net.Listener) error {
+	defer l.Close()
+	for {
+		c, err := l.Accept()
+		if err != nil {
+			return err
+		}
+		go func() {
+			conn := &Conn{clientConn: c, srv: s}
+			err := conn.Run()
+			if err != nil {
+				s.logf("client connection failed: %v", err)
+				conn.clientConn.Close()
+			}
+		}()
+	}
+}
+
+// Conn is a SOCKS5 connection for client to reach
+// server.
+type Conn struct {
+	// The struct is filled by each of the internal
+	// methods in turn as the transaction progresses.
+
+	srv        *Server
+	clientConn net.Conn
+	request    *request
+}
+
+// Run starts the new connection.
+func (c *Conn) Run() error {
+	err := parseClientGreeting(c.clientConn)
+	if err != nil {
+		c.clientConn.Write([]byte{socks5Version, noAcceptableAuth})
+		return err
+	}
+	c.clientConn.Write([]byte{socks5Version, noAuthRequired})
+	return c.handleRequest()
+}
+
+func (c *Conn) handleRequest() error {
+	req, err := parseClientRequest(c.clientConn)
+	if err != nil {
+		res := &response{reply: generalFailure}
+		buf, _ := res.marshal()
+		c.clientConn.Write(buf)
+		return err
+	}
+	if req.command != connect {
+		res := &response{reply: commandNotSupported}
+		buf, _ := res.marshal()
+		c.clientConn.Write(buf)
+		return fmt.Errorf("unsupported command %v", req.command)
+	}
+	c.request = req
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	srv, err := c.srv.dial(
+		ctx,
+		"tcp",
+		net.JoinHostPort(c.request.destination, strconv.Itoa(int(c.request.port))),
+	)
+	if err != nil {
+		res := &response{reply: generalFailure}
+		buf, _ := res.marshal()
+		c.clientConn.Write(buf)
+		return err
+	}
+	defer srv.Close()
+	serverAddr, serverPortStr, err := net.SplitHostPort(srv.LocalAddr().String())
+	if err != nil {
+		return err
+	}
+	serverPort, _ := strconv.Atoi(serverPortStr)
+
+	var bindAddrType addrType
+	if ip := net.ParseIP(serverAddr); ip != nil {
+		if ip.To4() != nil {
+			bindAddrType = ipv4
+		} else {
+			bindAddrType = ipv6
+		}
+	} else {
+		bindAddrType = domainName
+	}
+	res := &response{
+		reply:        success,
+		bindAddrType: bindAddrType,
+		bindAddr:     serverAddr,
+		bindPort:     uint16(serverPort),
+	}
+	buf, err := res.marshal()
+	if err != nil {
+		res = &response{reply: generalFailure}
+		buf, _ = res.marshal()
+	}
+	c.clientConn.Write(buf)
+
+	errc := make(chan error, 2)
+	go func() {
+		_, err := io.Copy(c.clientConn, srv)
+		if err != nil {
+			err = fmt.Errorf("from backend to client: %w", err)
+		}
+		errc <- err
+	}()
+	go func() {
+		_, err := io.Copy(srv, c.clientConn)
+		if err != nil {
+			err = fmt.Errorf("from client to backend: %w", err)
+		}
+		errc <- err
+	}()
+	return <-errc
+}
+
+// parseClientGreeting parses a request initiation packet
+// and returns a slice that contains the acceptable auth methods
+// for the client.
+func parseClientGreeting(r io.Reader) error {
+	var hdr [2]byte
+	_, err := io.ReadFull(r, hdr[:])
+	if err != nil {
+		return fmt.Errorf("could not read packet header")
+	}
+	if hdr[0] != socks5Version {
+		return fmt.Errorf("incompatible SOCKS version")
+	}
+	count := int(hdr[1])
+	methods := make([]byte, count)
+	_, err = io.ReadFull(r, methods)
+	if err != nil {
+		return fmt.Errorf("could not read methods")
+	}
+	for _, m := range methods {
+		if m == noAuthRequired {
+			return nil
+		}
+	}
+	return fmt.Errorf("no acceptable auth methods")
+}
+
+// request represents data contained within a SOCKS5
+// connection request packet.
+type request struct {
+	command      commandType
+	destination  string
+	port         uint16
+	destAddrType addrType
+}
+
+// parseClientRequest converts raw packet bytes into a
+// SOCKS5Request struct.
+func parseClientRequest(r io.Reader) (*request, error) {
+	var hdr [4]byte
+	_, err := io.ReadFull(r, hdr[:])
+	if err != nil {
+		return nil, fmt.Errorf("could not read packet header")
+	}
+	cmd := hdr[1]
+	destAddrType := addrType(hdr[3])
+
+	var destination string
+	var port uint16
+
+	if destAddrType == ipv4 {
+		var ip [4]byte
+		_, err = io.ReadFull(r, ip[:])
+		if err != nil {
+			return nil, fmt.Errorf("could not read IPv4 address")
+		}
+		destination = net.IP(ip[:]).String()
+	} else if destAddrType == domainName {
+		var dstSizeByte [1]byte
+		_, err = io.ReadFull(r, dstSizeByte[:])
+		if err != nil {
+			return nil, fmt.Errorf("could not read domain name size")
+		}
+		dstSize := int(dstSizeByte[0])
+		domainName := make([]byte, dstSize)
+		_, err = io.ReadFull(r, domainName)
+		if err != nil {
+			return nil, fmt.Errorf("could not read domain name")
+		}
+		destination = string(domainName)
+	} else if destAddrType == ipv6 {
+		var ip [16]byte
+		_, err = io.ReadFull(r, ip[:])
+		if err != nil {
+			return nil, fmt.Errorf("could not read IPv6 address")
+		}
+		destination = net.IP(ip[:]).String()
+	} else {
+		return nil, fmt.Errorf("unsupported address type")
+	}
+	var portBytes [2]byte
+	_, err = io.ReadFull(r, portBytes[:])
+	if err != nil {
+		return nil, fmt.Errorf("could not read port")
+	}
+	port = binary.BigEndian.Uint16(portBytes[:])
+
+	return &request{
+		command:      commandType(cmd),
+		destination:  destination,
+		port:         port,
+		destAddrType: destAddrType,
+	}, nil
+}
+
+// response contains the contents of
+// a response packet sent from the proxy
+// to the client.
+type response struct {
+	reply        replyCode
+	bindAddrType addrType
+	bindAddr     string
+	bindPort     uint16
+}
+
+// marshal converts a SOCKS5Response struct into
+// a packet. If res.reply == Success, it may throw an error on
+// receiving an invalid bind address. Otherwise, it will not throw.
+func (res *response) marshal() ([]byte, error) {
+	pkt := make([]byte, 4)
+	pkt[0] = socks5Version
+	pkt[1] = byte(res.reply)
+	pkt[2] = 0 // null reserved byte
+	pkt[3] = byte(res.bindAddrType)
+
+	if res.reply != success {
+		return pkt, nil
+	}
+
+	var addr []byte
+	switch res.bindAddrType {
+	case ipv4:
+		addr = net.ParseIP(res.bindAddr).To4()
+		if addr == nil {
+			return nil, fmt.Errorf("invalid IPv4 address for binding")
+		}
+	case domainName:
+		if len(res.bindAddr) > 255 {
+			return nil, fmt.Errorf("invalid domain name for binding")
+		}
+		addr = make([]byte, 0, len(res.bindAddr)+1)
+		addr = append(addr, byte(len(res.bindAddr)))
+		addr = append(addr, []byte(res.bindAddr)...)
+	case ipv6:
+		addr = net.ParseIP(res.bindAddr).To16()
+		if addr == nil {
+			return nil, fmt.Errorf("invalid IPv6 address for binding")
+		}
+	default:
+		return nil, fmt.Errorf("unsupported address type")
+	}
+
+	pkt = append(pkt, addr...)
+	port := make([]byte, 2)
+	binary.BigEndian.PutUint16(port, uint16(res.bindPort))
+	pkt = append(pkt, port...)
+
+	return pkt, nil
+}

net/stun/stuntest/stuntest.go

@@ -59,6 +59,7 @@ func runSTUN(t *testing.T, pc net.PacketConn, stats *stunStats, done chan<- stru
 	for {
 		n, addr, err := pc.ReadFrom(buf[:])
 		if err != nil {
+			// TODO: when we switch to Go 1.16, replace this with errors.Is(err, net.ErrClosed)
 			if strings.Contains(err.Error(), "closed network connection") {
 				t.Logf("STUN server shutdown")
 				return

net/tshttpproxy/tshttpproxy.go

@@ -71,6 +71,16 @@ func GetAuthHeader(u *url.URL) (string, error) {
 	if fake := os.Getenv("TS_DEBUG_FAKE_PROXY_AUTH"); fake != "" {
 		return fake, nil
 	}
+	if user := u.User.Username(); user != "" {
+		pass, ok := u.User.Password()
+		if !ok {
+			return "", nil
+		}
+
+		req := &http.Request{Header: make(http.Header)}
+		req.SetBasicAuth(user, pass)
+		return req.Header.Get("Authorization"), nil
+	}
 	if sysAuthHeader != nil {
 		return sysAuthHeader(u)
 	}

net/tshttpproxy/tshttpproxy_test.go

@@ -0,0 +1,53 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tshttpproxy
+
+import (
+	"net/url"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestGetAuthHeaderNoResult(t *testing.T) {
+	const proxyURL = "http://127.0.0.1:38274"
+
+	u, err := url.Parse(proxyURL)
+	if err != nil {
+		t.Fatalf("can't parse %q: %v", proxyURL, err)
+	}
+
+	got, err := GetAuthHeader(u)
+	if err != nil {
+		t.Fatalf("can't get auth header value: %v", err)
+	}
+
+	if runtime.GOOS == "windows" && strings.HasPrefix(got, "Negotiate") {
+		t.Logf("didn't get empty result, but got acceptable Windows Negotiate header")
+		return
+	}
+	if got != "" {
+		t.Fatalf("GetAuthHeader(%q) = %q; want empty string", proxyURL, got)
+	}
+}
+
+func TestGetAuthHeaderBasicAuth(t *testing.T) {
+	const proxyURL = "http://user:password@127.0.0.1:38274"
+	const want = "Basic dXNlcjpwYXNzd29yZA=="
+
+	u, err := url.Parse(proxyURL)
+	if err != nil {
+		t.Fatalf("can't parse %q: %v", proxyURL, err)
+	}
+
+	got, err := GetAuthHeader(u)
+	if err != nil {
+		t.Fatalf("can't get auth header value: %v", err)
+	}
+
+	if got != want {
+		t.Fatalf("GetAuthHeader(%q) = %q; want %q", proxyURL, got, want)
+	}
+}

paths/paths.go

@@ -8,6 +8,7 @@ package paths
 
 import (
 	"os"
+	"path/filepath"
 	"runtime"
 )
 
@@ -27,6 +28,9 @@ func DefaultTailscaledSocket() string {
 	if runtime.GOOS == "windows" {
 		return ""
 	}
+	if runtime.GOOS == "darwin" {
+		return "/var/run/tailscaled.socket"
+	}
 	if fi, err := os.Stat("/var/run"); err == nil && fi.IsDir() {
 		return "/var/run/tailscale/tailscaled.sock"
 	}
@@ -42,5 +46,8 @@ func DefaultTailscaledStateFile() string {
 	if f := stateFileFunc; f != nil {
 		return f()
 	}
+	if runtime.GOOS == "windows" {
+		return filepath.Join(os.Getenv("LocalAppData"), "Tailscale", "server-state.conf")
+	}
 	return ""
 }

paths/paths_unix.go

@@ -23,6 +23,8 @@ func statePath() string {
 		return "/var/lib/tailscale/tailscaled.state"
 	case "freebsd", "openbsd":
 		return "/var/db/tailscale/tailscaled.state"
+	case "darwin":
+		return "/Library/Tailscale/tailscaled.state"
 	default:
 		return ""
 	}

portlist/netstat.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !darwin !arm64
+// +build go1.16,!ios !go1.16,!darwin !go1.16,!arm64
 
 package portlist
 

portlist/netstat_exec.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.
 
-// +build windows freebsd openbsd darwin,amd64
+// +build windows freebsd openbsd darwin,go1.16 darwin,!go1.16,!arm64
+// +build !ios
 
 package portlist
 

portlist/portlist_ios.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin,!amd64
+// +build go1.16,ios !go1.16,darwin,!amd64
 
 package portlist
 

portlist/portlist_macos.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.
 
-// +build darwin,amd64
+// +build darwin,amd64,!go1.16 darwin,go1.16
+// +build !ios
 
 package portlist
 

portlist/portlist_test.go

@@ -12,8 +12,7 @@ import (
 )
 
 func TestGetList(t *testing.T) {
-	rc := tstest.NewResourceCheck()
-	defer rc.Assert(t)
+	tstest.ResourceCheck(t)
 
 	pl, err := GetList(nil)
 	if err != nil {
@@ -26,8 +25,7 @@ func TestGetList(t *testing.T) {
 }
 
 func TestIgnoreLocallyBoundPorts(t *testing.T) {
-	rc := tstest.NewResourceCheck()
-	defer rc.Assert(t)
+	tstest.ResourceCheck(t)
 
 	ln, err := net.Listen("tcp", "127.0.0.1:0")
 	if err != nil {

safesocket/basic_test.go

@@ -32,7 +32,7 @@ func TestBasics(t *testing.T) {
 			errs <- err
 			return
 		}
-		fmt.Printf("server read %d bytes.\n", n)
+		t.Logf("server read %d bytes.", n)
 		if string(b[:n]) != "world" {
 			errs <- fmt.Errorf("got %#v, expected %#v\n", string(b[:n]), "world")
 			return

safesocket/safesocket.go

@@ -7,7 +7,11 @@
 package safesocket
 
 import (
+	"errors"
 	"net"
+	"runtime"
+
+	"tailscale.com/paths"
 )
 
 type closeable interface {
@@ -27,6 +31,11 @@ func ConnCloseWrite(c net.Conn) error {
 	return c.(closeable).CloseWrite()
 }
 
+// ConnectDefault connects to the local Tailscale daemon.
+func ConnectDefault() (net.Conn, error) {
+	return Connect(paths.DefaultTailscaledSocket(), 41112)
+}
+
 // Connect connects to either path (on Unix) or the provided localhost port (on Windows).
 func Connect(path string, port uint16) (net.Conn, error) {
 	return connect(path, port)
@@ -38,3 +47,21 @@ func Connect(path string, port uint16) (net.Conn, error) {
 func Listen(path string, port uint16) (_ net.Listener, gotPort uint16, _ error) {
 	return listen(path, port)
 }
+
+var (
+	ErrTokenNotFound = errors.New("no token found")
+	ErrNoTokenOnOS   = errors.New("no token on " + runtime.GOOS)
+)
+
+var localTCPPortAndToken func() (port int, token string, err error)
+
+// LocalTCPPortAndToken returns the port number and auth token to connect to
+// the local Tailscale daemon. It's currently only applicable on macOS
+// when tailscaled is being run in the Mac Sandbox from the App Store version
+// of Tailscale.
+func LocalTCPPortAndToken() (port int, token string, err error) {
+	if localTCPPortAndToken == nil {
+		return 0, "", ErrNoTokenOnOS
+	}
+	return localTCPPortAndToken()
+}