fix include line

Adds the ability to probe for various capabilities. It will not call into C unless
necessary. It also allocates one probe per call to new capability, which may be expensive, so in
theory they could be reused instead.

Signed-off-by: kadmin <julianknodt@gmail.com>

.github/workflows/go_generate.yml

@@ -1,34 +0,0 @@
-name: go generate
-
-on:
-  push:
-    branches:
-      - main
-      - "release-branch/*"
-  pull_request:
-    branches:
-      - "*"
-
-jobs:
-  check:
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Set up Go
-        uses: actions/setup-go@v1
-        with:
-          go-version: 1.16
-
-      - name: Check out code
-        uses: actions/checkout@v2
-        with:
-          fetch-depth: 0
-
-      - name: check 'go generate' is clean
-        run: |
-          mkdir gentools
-          go build -o gentools/stringer golang.org/x/tools/cmd/stringer
-          PATH="$PATH:$(pwd)/gentools" go generate ./...
-          echo
-          echo
-          git diff --name-only --exit-code || (echo "The files above need updating. Please run 'go generate'."; exit 1)

.github/workflows/linux.yml

@@ -25,6 +25,9 @@ jobs:
     - name: Check out code into the Go module directory
       uses: actions/checkout@v1
 
+    - name: Install liburing
+      run: sudo apt install liburing-dev
+
     - name: Basic build
       run: go build ./cmd/...
 

.github/workflows/xe-experimental-vm-test.yml

@@ -4,6 +4,8 @@ on:
   pull_request:
     paths:
       - "tstest/integration/vms/**"
+  push:
+    branches: [ main ]
   release:
     types: [ created ]
 

Dockerfile

@@ -42,7 +42,8 @@ FROM golang:1.16-alpine AS build-env
 
 WORKDIR /go/src/tailscale
 
-COPY go.mod go.sum ./
+COPY go.mod .
+COPY go.sum .
 RUN go mod download
 
 COPY . .

VERSION.txt

@@ -1 +1 @@
-1.13.0
+1.11.0

cmd/addlicense/main.go

@@ -1,77 +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.
-
-// Program addlicense adds a license header to a file.
-// It is intended for use with 'go generate',
-// so it has a slightly weird usage.
-package main
-
-import (
-	"flag"
-	"fmt"
-	"os"
-	"os/exec"
-)
-
-var (
-	year = flag.Int("year", 0, "copyright year")
-	file = flag.String("file", "", "file to modify")
-)
-
-func usage() {
-	fmt.Fprintf(os.Stderr, `
-usage: addlicense -year YEAR -file FILE <subcommand args...>
-`[1:])
-
-	flag.PrintDefaults()
-	fmt.Fprintf(os.Stderr, `
-addlicense adds a Tailscale license to the beginning of file,
-using year as the copyright year.
-
-It is intended for use with 'go generate', so it also runs a subcommand,
-which presumably creates the file.
-
-Sample usage:
-
-addlicense -year 2021 -file pull_strings.go stringer -type=pull
-`[1:])
-	os.Exit(2)
-}
-
-func main() {
-	flag.Usage = usage
-	flag.Parse()
-	if len(flag.Args()) == 0 {
-		flag.Usage()
-	}
-	cmd := exec.Command(flag.Arg(0), flag.Args()[1:]...)
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
-	err := cmd.Run()
-	check(err)
-	b, err := os.ReadFile(*file)
-	check(err)
-	f, err := os.OpenFile(*file, os.O_TRUNC|os.O_WRONLY, 0644)
-	check(err)
-	_, err = fmt.Fprintf(f, license, *year)
-	check(err)
-	_, err = f.Write(b)
-	check(err)
-	err = f.Close()
-	check(err)
-}
-
-func check(err error) {
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
-}
-
-var license = `
-// Copyright (c) %d 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.
-
-`[1:]

cmd/derper/derper.go

@@ -58,12 +58,7 @@ func loadConfig() config {
 		return config{PrivateKey: mustNewKey()}
 	}
 	if *configPath == "" {
-		if os.Getuid() == 0 {
-			*configPath = "/var/lib/derper/derper.key"
-		} else {
-			log.Fatalf("derper: -c <config path> not specified")
-		}
-		log.Printf("no config path specified; using %s", *configPath)
+		log.Fatalf("derper: -c <config path> not specified")
 	}
 	b, err := ioutil.ReadFile(*configPath)
 	switch {

cmd/derper/mesh.go

@@ -9,9 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
-	"net"
 	"strings"
-	"time"
 
 	"tailscale.com/derp"
 	"tailscale.com/derp/derphttp"
@@ -41,34 +39,6 @@ func startMeshWithHost(s *derp.Server, host string) error {
 		return err
 	}
 	c.MeshKey = s.MeshKey()
-
-	// For meshed peers within a region, connect via VPC addresses.
-	c.SetURLDialer(func(ctx context.Context, network, addr string) (net.Conn, error) {
-		host, port, err := net.SplitHostPort(addr)
-		if err != nil {
-			return nil, err
-		}
-		var d net.Dialer
-		var r net.Resolver
-		if port == "443" && strings.HasSuffix(host, ".tailscale.com") {
-			base := strings.TrimSuffix(host, ".tailscale.com")
-			subCtx, cancel := context.WithTimeout(ctx, 2*time.Second)
-			defer cancel()
-			vpcHost := base + "-vpc.tailscale.com"
-			ips, _ := r.LookupIP(subCtx, "ip", vpcHost)
-			if len(ips) > 0 {
-				vpcAddr := net.JoinHostPort(ips[0].String(), port)
-				c, err := d.DialContext(subCtx, network, vpcAddr)
-				if err == nil {
-					log.Printf("connected to %v (%v) instead of %v", vpcHost, ips[0], base)
-					return c, nil
-				}
-				log.Printf("failed to connect to %v (%v): %v; trying non-VPC route", vpcHost, ips[0], err)
-			}
-		}
-		return d.DialContext(ctx, network, addr)
-	})
-
 	add := func(k key.Public) { s.AddPacketForwarder(k, c) }
 	remove := func(k key.Public) { s.RemovePacketForwarder(k, c) }
 	go c.RunWatchConnectionLoop(context.Background(), s.PublicKey(), logf, add, remove)

cmd/derpprobe/derpprobe.go

@@ -190,16 +190,6 @@ func probe() error {
 }
 
 func probeNodePair(ctx context.Context, dm *tailcfg.DERPMap, from, to *tailcfg.DERPNode) (latency time.Duration, err error) {
-	// The passed in context is a minute for the whole region. The
-	// idea is that each node pair in the region will be done
-	// serially and regularly in the future, reusing connections
-	// (at least in the happy path). For now they don't reuse
-	// connections and probe at most once every 15 seconds. We
-	// bound the duration of a single node pair within a region
-	// so one bad one can't starve others.
-	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
-	defer cancel()
-
 	fromc, err := newConn(ctx, dm, from)
 	if err != nil {
 		return 0, err
@@ -211,13 +201,6 @@ func probeNodePair(ctx context.Context, dm *tailcfg.DERPMap, from, to *tailcfg.D
 	}
 	defer toc.Close()
 
-	// Wait a bit for from's node to hear about to existing on the
-	// other node in the region, in the case where the two nodes
-	// are different.
-	if from.Name != to.Name {
-		time.Sleep(100 * time.Millisecond) // pretty arbitrary
-	}
-
 	// Make a random packet
 	pkt := make([]byte, 8)
 	crand.Read(pkt)

cmd/speedtest/speedtest.go

@@ -1,121 +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.
-
-// Program speedtest provides the speedtest command. The reason to keep it separate from
-// the normal tailscale cli is because it is not yet ready to go in the tailscale binary.
-// It will be included in the tailscale cli after it has been added to tailscaled.
-
-// Example usage for client command: go run cmd/speedtest -host 127.0.0.1:20333 -t 5s
-// This will connect to the server on 127.0.0.1:20333 and start a 5 second download speedtest.
-// Example usage for server command: go run cmd/speedtest -s -host :20333
-// This will start a speedtest server on port 20333.
-package main
-
-import (
-	"context"
-	"errors"
-	"flag"
-	"fmt"
-	"net"
-	"os"
-	"strconv"
-	"text/tabwriter"
-	"time"
-
-	"github.com/peterbourgon/ff/v2/ffcli"
-	"tailscale.com/net/speedtest"
-)
-
-// Runs the speedtest command as a commandline program
-func main() {
-	args := os.Args[1:]
-	if err := speedtestCmd.Parse(args); err != nil {
-		fmt.Fprintln(os.Stderr, err.Error())
-		os.Exit(1)
-	}
-
-	err := speedtestCmd.Run(context.Background())
-	if errors.Is(err, flag.ErrHelp) {
-		fmt.Fprintln(os.Stderr, speedtestCmd.ShortUsage)
-		os.Exit(2)
-	}
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err.Error())
-		os.Exit(1)
-	}
-}
-
-// speedtestCmd is the root command. It runs either the server or client depending on the
-// flags passed to it.
-var speedtestCmd = &ffcli.Command{
-	Name:       "speedtest",
-	ShortUsage: "speedtest [-host <host:port>] [-s] [-r] [-t <test duration>]",
-	ShortHelp:  "Run a speed test",
-	FlagSet: (func() *flag.FlagSet {
-		fs := flag.NewFlagSet("speedtest", flag.ExitOnError)
-		fs.StringVar(&speedtestArgs.host, "host", ":20333", "host:port pair to connect to or listen on")
-		fs.DurationVar(&speedtestArgs.testDuration, "t", speedtest.DefaultDuration, "duration of the speed test")
-		fs.BoolVar(&speedtestArgs.runServer, "s", false, "run a speedtest server")
-		fs.BoolVar(&speedtestArgs.reverse, "r", false, "run in reverse mode (server sends, client receives)")
-		return fs
-	})(),
-	Exec: runSpeedtest,
-}
-
-var speedtestArgs struct {
-	host         string
-	testDuration time.Duration
-	runServer    bool
-	reverse      bool
-}
-
-func runSpeedtest(ctx context.Context, args []string) error {
-
-	if _, _, err := net.SplitHostPort(speedtestArgs.host); err != nil {
-		var addrErr *net.AddrError
-		if errors.As(err, &addrErr) && addrErr.Err == "missing port in address" {
-			// if no port is provided, append the default port
-			speedtestArgs.host = net.JoinHostPort(speedtestArgs.host, strconv.Itoa(speedtest.DefaultPort))
-		}
-	}
-
-	if speedtestArgs.runServer {
-		listener, err := net.Listen("tcp", speedtestArgs.host)
-		if err != nil {
-			return err
-		}
-
-		fmt.Printf("listening on %v\n", listener.Addr())
-
-		return speedtest.Serve(listener)
-	}
-
-	// Ensure the duration is within the allowed range
-	if speedtestArgs.testDuration < speedtest.MinDuration || speedtestArgs.testDuration > speedtest.MaxDuration {
-		return fmt.Errorf("test duration must be within %v and %v", speedtest.MinDuration, speedtest.MaxDuration)
-	}
-
-	dir := speedtest.Download
-	if speedtestArgs.reverse {
-		dir = speedtest.Upload
-	}
-
-	fmt.Printf("Starting a %s test with %s\n", dir, speedtestArgs.host)
-	results, err := speedtest.RunClient(dir, speedtestArgs.testDuration, speedtestArgs.host)
-	if err != nil {
-		return err
-	}
-
-	w := tabwriter.NewWriter(os.Stdout, 12, 0, 0, ' ', tabwriter.TabIndent)
-	fmt.Println("Results:")
-	fmt.Fprintln(w, "Interval\t\tTransfer\t\tBandwidth\t\t")
-	for _, r := range results {
-		if r.Total {
-			fmt.Fprintln(w, "-------------------------------------------------------------------------")
-		}
-		fmt.Fprintf(w, "%.2f-%.2f\tsec\t%.4f\tMBits\t%.4f\tMbits/sec\t\n", r.IntervalStart.Seconds(), r.IntervalEnd.Seconds(), r.MegaBits(), r.MBitsPerSecond())
-	}
-	w.Flush()
-	return nil
-}

cmd/tailscale/cli/status.go

@@ -23,7 +23,6 @@ import (
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/net/interfaces"
-	"tailscale.com/tstime/mono"
 	"tailscale.com/util/dnsname"
 )
 
@@ -194,7 +193,7 @@ func runStatus(ctx context.Context, args []string) error {
 //
 // TODO: have the server report this bool instead.
 func peerActive(ps *ipnstate.PeerStatus) bool {
-	return !ps.LastWrite.IsZero() && mono.Since(ps.LastWrite) < 2*time.Minute
+	return !ps.LastWrite.IsZero() && time.Since(ps.LastWrite) < 2*time.Minute
 }
 
 func dnsOrQuoteHostname(st *ipnstate.Status, ps *ipnstate.PeerStatus) string {

cmd/tailscale/cli/up.go

@@ -51,14 +51,7 @@ flag is also used.
 	Exec:    runUp,
 }
 
-func effectiveGOOS() string {
-	if v := os.Getenv("TS_DEBUG_UP_FLAG_GOOS"); v != "" {
-		return v
-	}
-	return runtime.GOOS
-}
-
-var upFlagSet = newUpFlagSet(effectiveGOOS(), &upArgs)
+var upFlagSet = newUpFlagSet(runtime.GOOS, &upArgs)
 
 func newUpFlagSet(goos string, upArgs *upArgsT) *flag.FlagSet {
 	upf := flag.NewFlagSet("up", flag.ExitOnError)
@@ -70,13 +63,13 @@ func newUpFlagSet(goos string, upArgs *upArgsT) *flag.FlagSet {
 	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, or empty string to not use an exit node")
+	upf.StringVar(&upArgs.exitNodeIP, "exit-node", "", "Tailscale IP of the exit node for internet traffic")
 	upf.BoolVar(&upArgs.exitNodeAllowLANAccess, "exit-node-allow-lan-access", false, "Allow direct access to the local network when routing traffic via an exit node")
 	upf.BoolVar(&upArgs.shieldsUp, "shields-up", false, "don't allow incoming connections")
 	upf.StringVar(&upArgs.advertiseTags, "advertise-tags", "", "comma-separated ACL tags to request; each must start with \"tag:\" (e.g. \"tag:eng,tag:montreal,tag:ssh\")")
 	upf.StringVar(&upArgs.authKey, "authkey", "", "node authorization key")
 	upf.StringVar(&upArgs.hostname, "hostname", "", "hostname to use instead of the one provided by the OS")
-	upf.StringVar(&upArgs.advertiseRoutes, "advertise-routes", "", "routes to advertise to other nodes (comma-separated, e.g. \"10.0.0.0/8,192.168.0.0/24\") or empty string to not advertise routes")
+	upf.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 safesocket.GOOSUsesPeerCreds(goos) {
 		upf.StringVar(&upArgs.opUser, "operator", "", "Unix username to allow to operate on tailscaled without sudo")
@@ -334,7 +327,7 @@ func runUp(ctx context.Context, args []string) error {
 		}
 	}
 
-	prefs, err := prefsFromUpArgs(upArgs, warnf, st, effectiveGOOS())
+	prefs, err := prefsFromUpArgs(upArgs, warnf, st, runtime.GOOS)
 	if err != nil {
 		fatalf("%s", err)
 	}
@@ -351,7 +344,7 @@ func runUp(ctx context.Context, args []string) error {
 	}
 
 	env := upCheckEnv{
-		goos:          effectiveGOOS(),
+		goos:          runtime.GOOS,
 		user:          os.Getenv("USER"),
 		flagSet:       upFlagSet,
 		upArgs:        upArgs,
@@ -391,7 +384,7 @@ func runUp(ctx context.Context, args []string) error {
 		if n.ErrMessage != nil {
 			msg := *n.ErrMessage
 			if msg == ipn.ErrMsgPermissionDenied {
-				switch effectiveGOOS() {
+				switch runtime.GOOS {
 				case "windows":
 					msg += " (Tailscale service in use by other user?)"
 				default:
@@ -465,7 +458,7 @@ func runUp(ctx context.Context, args []string) error {
 		// Windows service (~tailscaled) is the one that computes the
 		// StateKey based on the connection identity. So for now, just
 		// do as the Windows GUI's always done:
-		if effectiveGOOS() == "windows" {
+		if runtime.GOOS == "windows" {
 			// The Windows service will set this as needed based
 			// on our connection's identity.
 			opts.StateKey = ""

cmd/tailscale/depaware.txt

@@ -7,12 +7,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
      💣 github.com/mitchellh/go-ps                                   from tailscale.com/cmd/tailscale/cli
         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/goupnp                                  from github.com/tailscale/goupnp/dcps/internetgateway2
-        github.com/tailscale/goupnp/dcps/internetgateway2            from tailscale.com/net/portmapper
-        github.com/tailscale/goupnp/httpu                            from github.com/tailscale/goupnp+
-        github.com/tailscale/goupnp/scpd                             from github.com/tailscale/goupnp
-        github.com/tailscale/goupnp/soap                             from github.com/tailscale/goupnp+
-        github.com/tailscale/goupnp/ssdp                             from github.com/tailscale/goupnp
         github.com/tcnksm/go-httpstat                                from tailscale.com/net/netcheck
         github.com/toqueteos/webbrowser                              from tailscale.com/cmd/tailscale/cli
      💣 go4.org/intern                                               from inet.af/netaddr
@@ -25,7 +19,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/client/tailscale                               from tailscale.com/cmd/tailscale/cli+
         tailscale.com/client/tailscale/apitype                       from tailscale.com/client/tailscale+
         tailscale.com/cmd/tailscale/cli                              from tailscale.com/cmd/tailscale
-        tailscale.com/control/controlknobs                           from tailscale.com/net/portmapper
         tailscale.com/derp                                           from tailscale.com/derp/derphttp
         tailscale.com/derp/derphttp                                  from tailscale.com/net/netcheck
         tailscale.com/disco                                          from tailscale.com/derp
@@ -49,8 +42,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/syncs                                          from tailscale.com/net/interfaces+
         tailscale.com/tailcfg                                        from tailscale.com/cmd/tailscale/cli+
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
-     💣 tailscale.com/tstime/mono                                    from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/tstime/rate                                    from tailscale.com/wgengine/filter
         tailscale.com/types/empty                                    from tailscale.com/ipn
         tailscale.com/types/ipproto                                  from tailscale.com/net/flowtrack+
         tailscale.com/types/key                                      from tailscale.com/derp+
@@ -86,7 +77,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         golang.org/x/net/idna                                        from golang.org/x/net/http/httpguts+
         golang.org/x/net/proxy                                       from tailscale.com/net/netns
    D    golang.org/x/net/route                                       from net+
-        golang.org/x/sync/errgroup                                   from tailscale.com/derp+
+        golang.org/x/sync/errgroup                                   from tailscale.com/derp
         golang.org/x/sync/singleflight                               from tailscale.com/net/dnscache
         golang.org/x/sys/cpu                                         from golang.org/x/crypto/blake2b+
   LD    golang.org/x/sys/unix                                        from tailscale.com/net/netns+
@@ -136,7 +127,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         encoding/hex                                                 from crypto/x509+
         encoding/json                                                from expvar+
         encoding/pem                                                 from crypto/tls+
-        encoding/xml                                                 from tailscale.com/cmd/tailscale/cli+
+        encoding/xml                                                 from tailscale.com/cmd/tailscale/cli
         errors                                                       from bufio+
         expvar                                                       from tailscale.com/derp+
         flag                                                         from github.com/peterbourgon/ff/v2+

cmd/tailscaled/debug.go

@@ -14,23 +14,18 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
-	"net"
 	"net/http"
 	"net/http/httptrace"
 	"net/url"
 	"os"
-	"strings"
 	"time"
 
-	"inet.af/netaddr"
 	"tailscale.com/derp/derphttp"
 	"tailscale.com/ipn"
 	"tailscale.com/net/interfaces"
-	"tailscale.com/net/portmapper"
 	"tailscale.com/net/tshttpproxy"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/key"
-	"tailscale.com/types/logger"
 	"tailscale.com/wgengine/monitor"
 )
 
@@ -38,7 +33,6 @@ var debugArgs struct {
 	monitor   bool
 	getURL    string
 	derpCheck string
-	portmap   bool
 }
 
 var debugModeFunc = debugMode // so it can be addressable
@@ -46,7 +40,6 @@ 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.BoolVar(&debugArgs.portmap, "portmap", false, "If true, run portmap debugging. 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 {
@@ -62,9 +55,6 @@ func debugMode(args []string) error {
 	if debugArgs.monitor {
 		return runMonitor(ctx)
 	}
-	if debugArgs.portmap {
-		return debugPortmap(ctx)
-	}
 	if debugArgs.getURL != "" {
 		return getURL(ctx, debugArgs.getURL)
 	}
@@ -201,83 +191,3 @@ func checkDerp(ctx context.Context, derpRegion string) error {
 	log.Printf("ok")
 	return err
 }
-
-func debugPortmap(ctx context.Context) error {
-	ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
-	defer cancel()
-
-	portmapper.VerboseLogs = true
-
-	done := make(chan bool, 1)
-
-	var c *portmapper.Client
-	logf := log.Printf
-	c = portmapper.NewClient(logger.WithPrefix(logf, "portmapper: "), func() {
-		logf("portmapping changed.")
-		logf("have mapping: %v", c.HaveMapping())
-
-		if ext, ok := c.GetCachedMappingOrStartCreatingOne(); ok {
-			logf("cb: mapping: %v", ext)
-			select {
-			case done <- true:
-			default:
-			}
-			return
-		}
-		logf("cb: no mapping")
-	})
-	linkMon, err := monitor.New(logger.WithPrefix(logf, "monitor: "))
-	if err != nil {
-		return err
-	}
-
-	gatewayAndSelfIP := func() (gw, self netaddr.IP, ok bool) {
-		if v := os.Getenv("TS_DEBUG_GW_SELF"); strings.Contains(v, "/") {
-			i := strings.Index(v, "/")
-			gw = netaddr.MustParseIP(v[:i])
-			self = netaddr.MustParseIP(v[i+1:])
-			return gw, self, true
-		}
-		return linkMon.GatewayAndSelfIP()
-	}
-
-	c.SetGatewayLookupFunc(gatewayAndSelfIP)
-
-	gw, selfIP, ok := gatewayAndSelfIP()
-	if !ok {
-		logf("no gateway or self IP; %v", linkMon.InterfaceState())
-		return nil
-	}
-	logf("gw=%v; self=%v", gw, selfIP)
-
-	res, err := c.Probe(ctx)
-	if err != nil {
-		return fmt.Errorf("Probe: %v", err)
-	}
-	logf("Probe: %+v", res)
-
-	if !res.PCP && !res.PMP && !res.UPnP {
-		logf("no portmapping services available")
-		return nil
-	}
-
-	uc, err := net.ListenPacket("udp", "0.0.0.0:0")
-	if err != nil {
-		return err
-	}
-	defer uc.Close()
-	c.SetLocalPort(uint16(uc.LocalAddr().(*net.UDPAddr).Port))
-
-	if ext, ok := c.GetCachedMappingOrStartCreatingOne(); ok {
-		logf("mapping: %v", ext)
-	} else {
-		logf("no mapping")
-	}
-
-	select {
-	case <-done:
-		return nil
-	case <-ctx.Done():
-		return ctx.Err()
-	}
-}

cmd/tailscaled/depaware.txt

@@ -23,12 +23,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    L 💣 github.com/mdlayher/socket                                   from github.com/mdlayher/netlink
    W    github.com/pkg/errors                                        from github.com/tailscale/certstore
    W 💣 github.com/tailscale/certstore                               from tailscale.com/control/controlclient
-        github.com/tailscale/goupnp                                  from github.com/tailscale/goupnp/dcps/internetgateway2
-        github.com/tailscale/goupnp/dcps/internetgateway2            from tailscale.com/net/portmapper
-        github.com/tailscale/goupnp/httpu                            from github.com/tailscale/goupnp+
-        github.com/tailscale/goupnp/scpd                             from github.com/tailscale/goupnp
-        github.com/tailscale/goupnp/soap                             from github.com/tailscale/goupnp+
-        github.com/tailscale/goupnp/ssdp                             from github.com/tailscale/goupnp
         github.com/tcnksm/go-httpstat                                from tailscale.com/net/netcheck
      💣 go4.org/intern                                               from inet.af/netaddr
      💣 go4.org/mem                                                  from tailscale.com/derp+
@@ -85,7 +79,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/client/tailscale                               from tailscale.com/derp
         tailscale.com/client/tailscale/apitype                       from tailscale.com/ipn/ipnlocal+
         tailscale.com/control/controlclient                          from tailscale.com/ipn/ipnlocal+
-        tailscale.com/control/controlknobs                           from tailscale.com/control/controlclient+
         tailscale.com/derp                                           from tailscale.com/derp/derphttp+
         tailscale.com/derp/derphttp                                  from tailscale.com/net/netcheck+
         tailscale.com/disco                                          from tailscale.com/derp+
@@ -130,8 +123,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/tailcfg                                        from tailscale.com/control/controlclient+
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
         tailscale.com/tstime                                         from tailscale.com/wgengine/magicsock
-     💣 tailscale.com/tstime/mono                                    from tailscale.com/net/tstun+
-        tailscale.com/tstime/rate                                    from tailscale.com/wgengine/filter
         tailscale.com/types/empty                                    from tailscale.com/control/controlclient+
         tailscale.com/types/flagtype                                 from tailscale.com/cmd/tailscaled
         tailscale.com/types/ipproto                                  from tailscale.com/net/flowtrack+
@@ -145,7 +136,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/types/structs                                  from tailscale.com/control/controlclient+
         tailscale.com/types/wgkey                                    from tailscale.com/control/controlclient+
    L    tailscale.com/util/cmpver                                    from tailscale.com/net/dns
-     💣 tailscale.com/util/deephash                                  from tailscale.com/ipn/ipnlocal+
+        tailscale.com/util/deephash                                  from tailscale.com/ipn/ipnlocal+
         tailscale.com/util/dnsname                                   from tailscale.com/ipn/ipnstate+
   LW    tailscale.com/util/endian                                    from tailscale.com/net/netns+
         tailscale.com/util/groupmember                               from tailscale.com/ipn/ipnserver
@@ -191,7 +182,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         golang.org/x/net/ipv6                                        from golang.zx2c4.com/wireguard/device+
         golang.org/x/net/proxy                                       from tailscale.com/net/netns
    D    golang.org/x/net/route                                       from net+
-        golang.org/x/sync/errgroup                                   from tailscale.com/derp+
+        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/mdlayher/netlink+
@@ -245,7 +236,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         encoding/hex                                                 from crypto/x509+
         encoding/json                                                from expvar+
         encoding/pem                                                 from crypto/tls+
-        encoding/xml                                                 from github.com/tailscale/goupnp+
         errors                                                       from bufio+
         expvar                                                       from tailscale.com/derp+
         flag                                                         from tailscale.com/cmd/tailscaled+

cmd/tailscaled/tailscaled.go

@@ -28,7 +28,6 @@ import (
 	"time"
 
 	"github.com/go-multierror/multierror"
-	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnserver"
 	"tailscale.com/logpolicy"
 	"tailscale.com/net/dns"
@@ -46,6 +45,15 @@ import (
 	"tailscale.com/wgengine/router"
 )
 
+// globalStateKey is the ipn.StateKey that tailscaled loads on
+// startup.
+//
+// We have to support multiple state keys for other OSes (Windows in
+// particular), but right now Unix daemons run with a single
+// node-global state. To keep open the option of having per-user state
+// later, the global state key doesn't look like a username.
+const globalStateKey = "_daemon"
+
 // defaultTunName returns the default tun device name for the platform.
 func defaultTunName() string {
 	switch runtime.GOOS {
@@ -159,28 +167,6 @@ func main() {
 	}
 }
 
-func ipnServerOpts() (o ipnserver.Options) {
-	// Allow changing the OS-specific IPN behavior for tests
-	// so we can e.g. test Windows-specific behaviors on Linux.
-	goos := os.Getenv("TS_DEBUG_TAILSCALED_IPN_GOOS")
-	if goos == "" {
-		goos = runtime.GOOS
-	}
-
-	o.Port = 41112
-	o.StatePath = args.statepath
-	o.SocketPath = args.socketpath // even for goos=="windows", for tests
-
-	switch goos {
-	default:
-		o.SurviveDisconnects = true
-		o.AutostartStateKey = ipn.GlobalDaemonStateKey
-	case "windows":
-		// Not those.
-	}
-	return o
-}
-
 func run() error {
 	var err error
 
@@ -210,9 +196,6 @@ func run() error {
 	logf = logger.RateLimitedFn(logf, 5*time.Second, 5, 100)
 
 	if args.cleanup {
-		if os.Getenv("TS_PLEASE_PANIC") != "" {
-			panic("TS_PLEASE_PANIC asked us to panic")
-		}
 		dns.Cleanup(logf, args.tunname)
 		router.Cleanup(logf, args.tunname)
 		return nil
@@ -288,8 +271,14 @@ func run() error {
 		}
 	}()
 
-	opts := ipnServerOpts()
-	opts.DebugMux = debugMux
+	opts := ipnserver.Options{
+		SocketPath:         args.socketpath,
+		Port:               41112,
+		StatePath:          args.statepath,
+		AutostartStateKey:  globalStateKey,
+		SurviveDisconnects: runtime.GOOS != "windows",
+		DebugMux:           debugMux,
+	}
 	err = ipnserver.Run(ctx, logf, pol.PublicID.String(), ipnserver.FixedEngine(e), opts)
 	// Cancelation is not an error: it is the only way to stop ipnserver.
 	if err != nil && err != context.Canceled {
@@ -352,7 +341,7 @@ func tryEngine(logf logger.Logf, linkMon *monitor.Mon, name string) (e wgengine.
 			return nil, false, err
 		}
 		conf.Tun = dev
-		r, err := router.New(logf, dev, linkMon)
+		r, err := router.New(logf, dev)
 		if err != nil {
 			dev.Close()
 			return nil, false, err

cmd/tailscaled/tailscaled_windows.go

@@ -168,7 +168,7 @@ func startIPNServer(ctx context.Context, logid string) error {
 		if err != nil {
 			return nil, fmt.Errorf("TUN: %w", err)
 		}
-		r, err := router.New(logf, dev, nil)
+		r, err := router.New(logf, dev)
 		if err != nil {
 			dev.Close()
 			return nil, fmt.Errorf("router: %w", err)
@@ -233,6 +233,12 @@ func startIPNServer(ctx context.Context, logid string) error {
 		}
 	}()
 
+	opts := ipnserver.Options{
+		Port:               41112,
+		SurviveDisconnects: false,
+		StatePath:          args.statepath,
+	}
+
 	// getEngine is called by ipnserver to get the engine. It's
 	// not called concurrently and is not called again once it
 	// successfully returns an engine.
@@ -257,7 +263,7 @@ func startIPNServer(ctx context.Context, logid string) error {
 			return nil, fmt.Errorf("%w\n\nlogid: %v", res.Err, logid)
 		}
 	}
-	err := ipnserver.Run(ctx, logf, logid, getEngine, ipnServerOpts())
+	err := ipnserver.Run(ctx, logf, logid, getEngine, opts)
 	if err != nil {
 		logf("ipnserver.Run: %v", err)
 	}

cmd/tsshd/tsshd.go

@@ -29,8 +29,8 @@ import (
 	"time"
 	"unsafe"
 
-	"github.com/creack/pty"
 	"github.com/gliderlabs/ssh"
+	"github.com/kr/pty"
 	gossh "golang.org/x/crypto/ssh"
 	"inet.af/netaddr"
 	"tailscale.com/net/interfaces"

control/controlclient/debug.go

@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"regexp"
 	"runtime"
 	"strconv"
 	"time"
@@ -41,82 +42,28 @@ func dumpGoroutinesToURL(c *http.Client, targetURL string) {
 	}
 }
 
+var reHexArgs = regexp.MustCompile(`\b0x[0-9a-f]+\b`)
+
 // scrubbedGoroutineDump returns the list of all current goroutines, but with the actual
 // values of arguments scrubbed out, lest it contain some private key material.
 func scrubbedGoroutineDump() []byte {
-	var buf []byte
-	// Grab stacks multiple times into increasingly larger buffer sizes
-	// to minimize the risk that we blow past our iOS memory limit.
-	for size := 1 << 10; size <= 1<<20; size += 1 << 10 {
-		buf = make([]byte, size)
-		buf = buf[:runtime.Stack(buf, true)]
-		if len(buf) < size {
-			// It fit.
-			break
-		}
-	}
-	return scrubHex(buf)
-}
+	buf := make([]byte, 1<<20)
+	buf = buf[:runtime.Stack(buf, true)]
 
-func scrubHex(buf []byte) []byte {
 	saw := map[string][]byte{} // "0x123" => "v1%3" (unique value 1 and its value mod 8)
-
-	foreachHexAddress(buf, func(in []byte) {
+	return reHexArgs.ReplaceAllFunc(buf, func(in []byte) []byte {
 		if string(in) == "0x0" {
-			return
+			return in
 		}
 		if v, ok := saw[string(in)]; ok {
-			for i := range in {
-				in[i] = '_'
-			}
-			copy(in, v)
-			return
+			return v
 		}
-		inStr := string(in)
 		u64, err := strconv.ParseUint(string(in[2:]), 16, 64)
-		for i := range in {
-			in[i] = '_'
-		}
 		if err != nil {
-			in[0] = '?'
-			return
+			return []byte("??")
 		}
 		v := []byte(fmt.Sprintf("v%d%%%d", len(saw)+1, u64%8))
-		saw[inStr] = v
-		copy(in, v)
+		saw[string(in)] = v
+		return v
 	})
-	return buf
-}
-
-var ohx = []byte("0x")
-
-// foreachHexAddress calls f with each subslice of b that matches
-// regexp `0x[0-9a-f]*`.
-func foreachHexAddress(b []byte, f func([]byte)) {
-	for len(b) > 0 {
-		i := bytes.Index(b, ohx)
-		if i == -1 {
-			return
-		}
-		b = b[i:]
-		hx := hexPrefix(b)
-		f(hx)
-		b = b[len(hx):]
-	}
-}
-
-func hexPrefix(b []byte) []byte {
-	for i, c := range b {
-		if i < 2 {
-			continue
-		}
-		if !isHexByte(c) {
-			return b[:i]
-		}
-	}
-	return b
-}
-
-func isHexByte(b byte) bool {
-	return '0' <= b && b <= '9' || 'a' <= b && b <= 'f' || 'A' <= b && b <= 'F'
 }

control/controlclient/debug_test.go

@@ -9,22 +9,3 @@ import "testing"
 func TestScrubbedGoroutineDump(t *testing.T) {
 	t.Logf("Got:\n%s\n", scrubbedGoroutineDump())
 }
-
-func TestScrubHex(t *testing.T) {
-	tests := []struct {
-		in, want string
-	}{
-		{"foo", "foo"},
-		{"", ""},
-		{"0x", "?_"},
-		{"0x001 and same 0x001", "v1%1_ and same v1%1_"},
-		{"0x008 and same 0x008", "v1%0_ and same v1%0_"},
-		{"0x001 and diff 0x002", "v1%1_ and diff v2%2_"},
-	}
-	for _, tt := range tests {
-		got := scrubHex([]byte(tt.in))
-		if string(got) != tt.want {
-			t.Errorf("for input:\n%s\n\ngot:\n%s\n\nwant:\n%s\n", tt.in, got, tt.want)
-		}
-	}
-}

control/controlclient/direct.go

@@ -31,7 +31,6 @@ import (
 
 	"golang.org/x/crypto/nacl/box"
 	"inet.af/netaddr"
-	"tailscale.com/control/controlknobs"
 	"tailscale.com/health"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/log/logheap"
@@ -220,13 +219,6 @@ func packageType() string {
 		// Using tailscaled or IPNExtension?
 		exe, _ := os.Executable()
 		return filepath.Base(exe)
-	case "linux":
-		// Report whether this is in a snap.
-		// See https://snapcraft.io/docs/environment-variables
-		// We just look at two somewhat arbitrarily.
-		if os.Getenv("SNAP_NAME") != "" && os.Getenv("SNAP") != "" {
-			return "snap"
-		}
 	}
 	return ""
 }
@@ -805,10 +797,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 			continue
 		}
 
-		hasDebug := resp.Debug != nil
-		// being conservative here, if Debug not present set to False
-		controlknobs.SetDisableUPnP(hasDebug && resp.Debug.DisableUPnP.EqualBool(true))
-		if hasDebug {
+		if resp.Debug != nil {
 			if resp.Debug.LogHeapPprof {
 				go logheap.LogHeap(resp.Debug.LogHeapURL)
 			}

control/controlknobs/controlknobs.go

@@ -1,34 +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 controlknobs contains client options configurable from control which can be turned on
-// or off. The ability to turn options on and off is for incrementally adding features in.
-package controlknobs
-
-import (
-	"os"
-	"strconv"
-
-	"tailscale.com/syncs"
-)
-
-// disableUPnP indicates whether to attempt UPnP mapping.
-var disableUPnP syncs.AtomicBool
-
-func init() {
-	v, _ := strconv.ParseBool(os.Getenv("TS_DISABLE_UPNP"))
-	SetDisableUPnP(v)
-}
-
-// DisableUPnP reports the last reported value from control
-// whether UPnP portmapping should be disabled.
-func DisableUPnP() bool {
-	return disableUPnP.Get()
-}
-
-// SetDisableUPnP sets whether control says that UPnP should be
-// disabled.
-func SetDisableUPnP(v bool) {
-	disableUPnP.Set(v)
-}

derp/derp_server.go

@@ -36,7 +36,6 @@ import (
 	"go4.org/mem"
 	"golang.org/x/crypto/nacl/box"
 	"golang.org/x/sync/errgroup"
-	"golang.org/x/time/rate"
 	"inet.af/netaddr"
 	"tailscale.com/client/tailscale"
 	"tailscale.com/disco"
@@ -119,8 +118,6 @@ type Server struct {
 	curClients                   expvar.Int
 	curHomeClients               expvar.Int // ones with preferred
 	clientsReplaced              expvar.Int
-	clientsReplaceLimited        expvar.Int
-	clientsReplaceSleeping       expvar.Int
 	unknownFrames                expvar.Int
 	homeMovesIn                  expvar.Int // established clients announce home server moves in
 	homeMovesOut                 expvar.Int // established clients announce home server moves out
@@ -167,7 +164,7 @@ type PacketForwarder interface {
 // Conn is the subset of the underlying net.Conn the DERP Server needs.
 // It is a defined type so that non-net connections can be used.
 type Conn interface {
-	io.WriteCloser
+	io.Closer
 
 	// The *Deadline methods follow the semantics of net.Conn.
 
@@ -349,28 +346,14 @@ func (s *Server) initMetacert() {
 func (s *Server) MetaCert() []byte { return s.metaCert }
 
 // registerClient notes that client c is now authenticated and ready for packets.
-//
-// If c's public key was already connected with a different
-// connection, the prior one is closed, unless it's fighting rapidly
-// with another client with the same key, in which case the returned
-// ok is false, and the caller should wait the provided duration
-// before trying again.
-func (s *Server) registerClient(c *sclient) (ok bool, d time.Duration) {
+// If c's public key was already connected with a different connection, the prior one is closed.
+func (s *Server) registerClient(c *sclient) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 	old := s.clients[c.key]
 	if old == nil {
 		c.logf("adding connection")
 	} else {
-		// Take over the old rate limiter, discarding the one
-		// our caller just made.
-		c.replaceLimiter = old.replaceLimiter
-		if rr := c.replaceLimiter.ReserveN(timeNow(), 1); rr.OK() {
-			if d := rr.DelayFrom(timeNow()); d > 0 {
-				s.clientsReplaceLimited.Add(1)
-				return false, d
-			}
-		}
 		s.clientsReplaced.Add(1)
 		c.logf("adding connection, replacing %s", old.remoteAddr)
 		go old.nc.Close()
@@ -382,7 +365,6 @@ func (s *Server) registerClient(c *sclient) (ok bool, d time.Duration) {
 	s.keyOfAddr[c.remoteIPPort] = c.key
 	s.curClients.Add(1)
 	s.broadcastPeerStateChangeLocked(c.key, true)
-	return true, 0
 }
 
 // broadcastPeerStateChangeLocked enqueues a message to all watchers
@@ -470,9 +452,8 @@ func (s *Server) addWatcher(c *sclient) {
 }
 
 func (s *Server) accept(nc Conn, brw *bufio.ReadWriter, remoteAddr string, connNum int64) error {
-	br := brw.Reader
+	br, bw := brw.Reader, brw.Writer
 	nc.SetDeadline(time.Now().Add(10 * time.Second))
-	bw := &lazyBufioWriter{w: nc, lbw: brw.Writer}
 	if err := s.sendServerKey(bw); err != nil {
 		return fmt.Errorf("send server key: %v", err)
 	}
@@ -509,14 +490,7 @@ func (s *Server) accept(nc Conn, brw *bufio.ReadWriter, remoteAddr string, connN
 		discoSendQueue: make(chan pkt, perClientSendQueueDepth),
 		peerGone:       make(chan key.Public),
 		canMesh:        clientInfo.MeshKey != "" && clientInfo.MeshKey == s.meshKey,
-
-		// Allow kicking out previous connections once a
-		// minute, with a very high burst of 100. Once a
-		// minute is less than the client's 2 minute
-		// inactivity timeout.
-		replaceLimiter: rate.NewLimiter(rate.Every(time.Minute), 100),
 	}
-
 	if c.canMesh {
 		c.meshUpdate = make(chan struct{})
 	}
@@ -524,18 +498,10 @@ func (s *Server) accept(nc Conn, brw *bufio.ReadWriter, remoteAddr string, connN
 		c.info = *clientInfo
 	}
 
-	for {
-		ok, d := s.registerClient(c)
-		if ok {
-			break
-		}
-		s.clientsReplaceSleeping.Add(1)
-		timeSleep(d)
-		s.clientsReplaceSleeping.Add(-1)
-	}
+	s.registerClient(c)
 	defer s.unregisterClient(c)
 
-	err = s.sendServerInfo(c.bw, clientKey)
+	err = s.sendServerInfo(bw, clientKey)
 	if err != nil {
 		return fmt.Errorf("send server info: %v", err)
 	}
@@ -543,12 +509,6 @@ func (s *Server) accept(nc Conn, brw *bufio.ReadWriter, remoteAddr string, connN
 	return c.run(ctx)
 }
 
-// for testing
-var (
-	timeSleep = time.Sleep
-	timeNow   = time.Now
-)
-
 // run serves the client until there's an error.
 // If the client hangs up or the server is closed, run returns nil, otherwise run returns an error.
 func (c *sclient) run(ctx context.Context) error {
@@ -738,7 +698,7 @@ func (c *sclient) handleFrameSendPacket(ft frameType, fl uint32) error {
 // dropReason is why we dropped a DERP frame.
 type dropReason int
 
-//go:generate go run tailscale.com/cmd/addlicense -year 2021 -file dropreason_string.go go run golang.org/x/tools/cmd/stringer -type=dropReason -trimprefix=dropReason
+//go:generate stringer -type=dropReason -trimprefix=dropReason
 
 const (
 	dropReasonUnknownDest      dropReason = iota // unknown destination pubkey
@@ -847,20 +807,18 @@ func (s *Server) verifyClient(clientKey key.Public, info *clientInfo) error {
 	return nil
 }
 
-func (s *Server) sendServerKey(lw *lazyBufioWriter) error {
+func (s *Server) sendServerKey(bw *bufio.Writer) error {
 	buf := make([]byte, 0, len(magic)+len(s.publicKey))
 	buf = append(buf, magic...)
 	buf = append(buf, s.publicKey[:]...)
-	err := writeFrame(lw.bw(), frameServerKey, buf)
-	lw.Flush() // redundant (no-op) flush to release bufio.Writer
-	return err
+	return writeFrame(bw, frameServerKey, buf)
 }
 
 type serverInfo struct {
 	Version int `json:"version,omitempty"`
 }
 
-func (s *Server) sendServerInfo(bw *lazyBufioWriter, clientKey key.Public) error {
+func (s *Server) sendServerInfo(bw *bufio.Writer, clientKey key.Public) error {
 	var nonce [24]byte
 	if _, err := crand.Read(nonce[:]); err != nil {
 		return err
@@ -871,7 +829,7 @@ func (s *Server) sendServerInfo(bw *lazyBufioWriter, clientKey key.Public) error
 	}
 
 	msgbox := box.Seal(nil, msg, &nonce, clientKey.B32(), s.privateKey.B32())
-	if err := writeFrameHeader(bw.bw(), frameServerInfo, nonceLen+uint32(len(msgbox))); err != nil {
+	if err := writeFrameHeader(bw, frameServerInfo, nonceLen+uint32(len(msgbox))); err != nil {
 		return err
 	}
 	if _, err := bw.Write(nonce[:]); err != nil {
@@ -994,18 +952,13 @@ type sclient struct {
 	meshUpdate     chan struct{}   // write request to write peerStateChange
 	canMesh        bool            // clientInfo had correct mesh token for inter-region routing
 
-	// replaceLimiter controls how quickly two connections with
-	// the same client key can kick each other off the server by
-	// taking over ownership of a key.
-	replaceLimiter *rate.Limiter
-
 	// Owned by run, not thread-safe.
 	br          *bufio.Reader
 	connectedAt time.Time
 	preferred   bool
 
 	// Owned by sender, not thread-safe.
-	bw *lazyBufioWriter
+	bw *bufio.Writer
 
 	// Guarded by s.mu
 	//
@@ -1167,14 +1120,14 @@ func (c *sclient) setWriteDeadline() {
 // sendKeepAlive sends a keep-alive frame, without flushing.
 func (c *sclient) sendKeepAlive() error {
 	c.setWriteDeadline()
-	return writeFrameHeader(c.bw.bw(), frameKeepAlive, 0)
+	return writeFrameHeader(c.bw, frameKeepAlive, 0)
 }
 
 // sendPeerGone sends a peerGone frame, without flushing.
 func (c *sclient) sendPeerGone(peer key.Public) error {
 	c.s.peerGoneFrames.Add(1)
 	c.setWriteDeadline()
-	if err := writeFrameHeader(c.bw.bw(), framePeerGone, keyLen); err != nil {
+	if err := writeFrameHeader(c.bw, framePeerGone, keyLen); err != nil {
 		return err
 	}
 	_, err := c.bw.Write(peer[:])
@@ -1184,7 +1137,7 @@ func (c *sclient) sendPeerGone(peer key.Public) error {
 // sendPeerPresent sends a peerPresent frame, without flushing.
 func (c *sclient) sendPeerPresent(peer key.Public) error {
 	c.setWriteDeadline()
-	if err := writeFrameHeader(c.bw.bw(), framePeerPresent, keyLen); err != nil {
+	if err := writeFrameHeader(c.bw, framePeerPresent, keyLen); err != nil {
 		return err
 	}
 	_, err := c.bw.Write(peer[:])
@@ -1257,11 +1210,11 @@ func (c *sclient) sendPacket(srcKey key.Public, contents []byte) (err error) {
 	if withKey {
 		pktLen += len(srcKey)
 	}
-	if err = writeFrameHeader(c.bw.bw(), frameRecvPacket, uint32(pktLen)); err != nil {
+	if err = writeFrameHeader(c.bw, frameRecvPacket, uint32(pktLen)); err != nil {
 		return err
 	}
 	if withKey {
-		err := writePublicKey(c.bw.bw(), &srcKey)
+		err := writePublicKey(c.bw, &srcKey)
 		if err != nil {
 			return err
 		}
@@ -1398,8 +1351,6 @@ func (s *Server) ExpVar() expvar.Var {
 	m.Set("gauge_clients_remote", expvar.Func(func() interface{} { return len(s.clientsMesh) - len(s.clients) }))
 	m.Set("accepts", &s.accepts)
 	m.Set("clients_replaced", &s.clientsReplaced)
-	m.Set("clients_replace_limited", &s.clientsReplaceLimited)
-	m.Set("gauge_clients_replace_sleeping", &s.clientsReplaceSleeping)
 	m.Set("bytes_received", &s.bytesRecv)
 	m.Set("bytes_sent", &s.bytesSent)
 	m.Set("packets_dropped", &s.packetsDropped)
@@ -1576,45 +1527,3 @@ func (s *Server) ServeDebugTraffic(w http.ResponseWriter, r *http.Request) {
 		time.Sleep(minTimeBetweenLogs)
 	}
 }
-
-var bufioWriterPool = &sync.Pool{
-	New: func() interface{} {
-		return bufio.NewWriterSize(ioutil.Discard, 2<<10)
-	},
-}
-
-// lazyBufioWriter is a bufio.Writer-like wrapping writer that lazily
-// allocates its actual bufio.Writer from a sync.Pool, releasing it to
-// the pool upon flush.
-//
-// We do this to reduce memory overhead; most DERP connections are
-// idle and the idle bufio.Writers were 30% of overall memory usage.
-type lazyBufioWriter struct {
-	w   io.Writer     // underlying
-	lbw *bufio.Writer // lazy; nil means it needs an associated buffer
-}
-
-func (w *lazyBufioWriter) bw() *bufio.Writer {
-	if w.lbw == nil {
-		w.lbw = bufioWriterPool.Get().(*bufio.Writer)
-		w.lbw.Reset(w.w)
-	}
-	return w.lbw
-}
-
-func (w *lazyBufioWriter) Available() int { return w.bw().Available() }
-
-func (w *lazyBufioWriter) Write(p []byte) (int, error) { return w.bw().Write(p) }
-
-func (w *lazyBufioWriter) Flush() error {
-	if w.lbw == nil {
-		return nil
-	}
-	err := w.lbw.Flush()
-
-	w.lbw.Reset(ioutil.Discard)
-	bufioWriterPool.Put(w.lbw)
-	w.lbw = nil
-
-	return err
-}

derp/derp_test.go

@@ -23,7 +23,6 @@ import (
 	"testing"
 	"time"
 
-	"golang.org/x/time/rate"
 	"tailscale.com/net/nettest"
 	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
@@ -850,136 +849,6 @@ func TestClientSendPong(t *testing.T) {
 
 }
 
-func TestServerReplaceClients(t *testing.T) {
-	defer func() {
-		timeSleep = time.Sleep
-		timeNow = time.Now
-	}()
-
-	var (
-		mu     sync.Mutex
-		now    = time.Unix(123, 0)
-		sleeps int
-		slept  time.Duration
-	)
-	timeSleep = func(d time.Duration) {
-		mu.Lock()
-		defer mu.Unlock()
-		sleeps++
-		slept += d
-		now = now.Add(d)
-	}
-	timeNow = func() time.Time {
-		mu.Lock()
-		defer mu.Unlock()
-		return now
-	}
-
-	serverPrivateKey := newPrivateKey(t)
-	var logger logger.Logf = logger.Discard
-	const debug = false
-	if debug {
-		logger = t.Logf
-	}
-
-	s := NewServer(serverPrivateKey, logger)
-	defer s.Close()
-
-	priv := newPrivateKey(t)
-
-	ln, err := net.Listen("tcp", "127.0.0.1:0")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer ln.Close()
-
-	connNum := 0
-	connect := func() *Client {
-		connNum++
-		cout, err := net.Dial("tcp", ln.Addr().String())
-		if err != nil {
-			t.Fatal(err)
-		}
-
-		cin, err := ln.Accept()
-		if err != nil {
-			t.Fatal(err)
-		}
-
-		brwServer := bufio.NewReadWriter(bufio.NewReader(cin), bufio.NewWriter(cin))
-		go s.Accept(cin, brwServer, fmt.Sprintf("test-client-%d", connNum))
-
-		brw := bufio.NewReadWriter(bufio.NewReader(cout), bufio.NewWriter(cout))
-		c, err := NewClient(priv, cout, brw, logger)
-		if err != nil {
-			t.Fatalf("client %d: %v", connNum, err)
-		}
-		return c
-	}
-
-	wantVar := func(v *expvar.Int, want int64) {
-		t.Helper()
-		if got := v.Value(); got != want {
-			t.Errorf("got %d; want %d", got, want)
-		}
-	}
-
-	wantClosed := func(c *Client) {
-		t.Helper()
-		for {
-			m, err := c.Recv()
-			if err != nil {
-				t.Logf("got expected error: %v", err)
-				return
-			}
-			switch m.(type) {
-			case ServerInfoMessage:
-				continue
-			default:
-				t.Fatalf("client got %T; wanted an error", m)
-			}
-		}
-	}
-
-	c1 := connect()
-	waitConnect(t, c1)
-	c2 := connect()
-	waitConnect(t, c2)
-	wantVar(&s.clientsReplaced, 1)
-	wantClosed(c1)
-
-	for i := 0; i < 100+5; i++ {
-		c := connect()
-		defer c.nc.Close()
-		if s.clientsReplaceLimited.Value() == 0 && i < 90 {
-			continue
-		}
-		t.Logf("for %d: replaced=%d, limited=%d, sleeping=%d", i,
-			s.clientsReplaced.Value(),
-			s.clientsReplaceLimited.Value(),
-			s.clientsReplaceSleeping.Value(),
-		)
-	}
-
-	mu.Lock()
-	defer mu.Unlock()
-	if sleeps == 0 {
-		t.Errorf("no sleeps")
-	}
-	if slept == 0 {
-		t.Errorf("total sleep duration was 0")
-	}
-}
-
-func TestLimiter(t *testing.T) {
-	rl := rate.NewLimiter(rate.Every(time.Minute), 100)
-	for i := 0; i < 200; i++ {
-		r := rl.Reserve()
-		d := r.Delay()
-		t.Logf("i=%d, allow=%v, d=%v", i, r.OK(), d)
-	}
-}
-
 func BenchmarkSendRecv(b *testing.B) {
 	for _, size := range []int{10, 100, 1000, 10000} {
 		b.Run(fmt.Sprintf("msgsize=%d", size), func(b *testing.B) { benchmarkSendRecvSize(b, size) })

derp/derphttp/derphttp_client.go

@@ -54,7 +54,6 @@ type Client struct {
 
 	privateKey key.Private
 	logf       logger.Logf
-	dialer     func(ctx context.Context, network, addr string) (net.Conn, error)
 
 	// Either url or getRegion is non-nil:
 	url       *url.URL
@@ -364,26 +363,14 @@ func (c *Client) connect(ctx context.Context, caller string) (client *derp.Clien
 	return c.client, c.connGen, nil
 }
 
-// SetURLDialer sets the dialer to use for dialing URLs.
-// This dialer is only use for clients created with NewClient, not NewRegionClient.
-// If unset or nil, the default dialer is used.
-//
-// The primary use for this is the derper mesh mode to connect to each
-// other over a VPC network.
-func (c *Client) SetURLDialer(dialer func(ctx context.Context, network, addr string) (net.Conn, error)) {
-	c.dialer = dialer
-}
-
 func (c *Client) dialURL(ctx context.Context) (net.Conn, error) {
 	host := c.url.Hostname()
-	if c.dialer != nil {
-		return c.dialer(ctx, "tcp", net.JoinHostPort(host, urlPort(c.url)))
-	}
 	hostOrIP := host
+
 	dialer := netns.NewDialer()
 
 	if c.DNSCache != nil {
-		ip, _, _, err := c.DNSCache.LookupIP(ctx, host)
+		ip, _, err := c.DNSCache.LookupIP(ctx, host)
 		if err == nil {
 			hostOrIP = ip.String()
 		}

derp/dropreason_string.go

@@ -1,7 +1,3 @@
-// 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.
-
 // Code generated by "stringer -type=dropReason -trimprefix=dropReason"; DO NOT EDIT.
 
 package derp

go.mod

@@ -7,8 +7,6 @@ require (
 	github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be // indirect
 	github.com/aws/aws-sdk-go v1.38.52
 	github.com/coreos/go-iptables v0.6.0
-	github.com/creack/pty v1.1.9
-	github.com/dave/jennifer v1.4.1
 	github.com/frankban/quicktest v1.13.0
 	github.com/gliderlabs/ssh v0.3.2
 	github.com/go-multierror/multierror v1.0.2
@@ -18,10 +16,10 @@ require (
 	github.com/google/goexpect v0.0.0-20210430020637-ab937bf7fd6f
 	github.com/google/uuid v1.1.2
 	github.com/goreleaser/nfpm v1.10.3
-	github.com/iancoleman/strcase v0.2.0
 	github.com/jsimonetti/rtnetlink v0.0.0-20210525051524-4cc836578190
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51
 	github.com/klauspost/compress v1.12.2
+	github.com/kr/pty v1.1.8
 	github.com/mdlayher/netlink v1.4.1
 	github.com/mdlayher/sdnotify v0.0.0-20210228150836-ea3ec207d697
 	github.com/miekg/dns v1.1.42
@@ -31,8 +29,6 @@ require (
 	github.com/pkg/sftp v1.13.0
 	github.com/tailscale/certstore v0.0.0-20210528134328-066c94b793d3
 	github.com/tailscale/depaware v0.0.0-20201214215404-77d1e9757027
-	github.com/tailscale/goupnp v1.0.1-0.20210804011211-c64d0f06ea05
-	github.com/tailscale/hujson v0.0.0-20200924210142-dde312d0d6a2
 	github.com/tcnksm/go-httpstat v0.2.0
 	github.com/toqueteos/webbrowser v1.2.0
 	go4.org/mem v0.0.0-20201119185036-c04c5a6ff174
@@ -46,7 +42,7 @@ require (
 	golang.zx2c4.com/wireguard v0.0.0-20210624150102-15b24b6179e0
 	golang.zx2c4.com/wireguard/windows v0.3.16
 	honnef.co/go/tools v0.1.4
-	inet.af/netaddr v0.0.0-20210721214506-ce7a8ad02cc1
+	inet.af/netaddr v0.0.0-20210602152128-50f8686885e3
 	inet.af/netstack v0.0.0-20210622165351-29b14ebc044e
 	inet.af/peercred v0.0.0-20210318190834-4259e17bb763
 	inet.af/wf v0.0.0-20210516214145-a5343001b756

go.sum

@@ -82,13 +82,12 @@ github.com/coreos/go-semver v0.3.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3Ee
 github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
+github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
 github.com/creack/pty v1.1.9 h1:uDmaGzcdjhF4i/plgjmEsriH11Y0o7RKapEf/LDaM3w=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/daixiang0/gci v0.2.4/go.mod h1:+AV8KmHTGxxwp/pY84TLQfFKp2vuKXXJVzF3kD/hfR4=
 github.com/daixiang0/gci v0.2.7 h1:bosLNficubzJZICsVzxuyNc6oAbdz0zcqLG2G/RxtY4=
 github.com/daixiang0/gci v0.2.7/go.mod h1:+4dZ7TISfSmqfAGv59ePaHfNzgGtIkHAhhdKggP1JAc=
-github.com/dave/jennifer v1.4.1 h1:XyqG6cn5RQsTj3qlWQTKlRGAyrTcsk1kUmWdZBzRjDw=
-github.com/dave/jennifer v1.4.1/go.mod h1:7jEdnm+qBcxl8PC0zyp7vxcpSRnzXSt9r39tpTVGlwA=
 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=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -297,8 +296,6 @@ github.com/hashicorp/serf v0.8.2/go.mod h1:6hOLApaqBFA1NXqRQAsxw9QxuDEvNxSQRwA/J
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/huandu/xstrings v1.3.2 h1:L18LIDzqlW6xN2rEkpdV8+oL/IXWJ1APd+vsdYy4Wdw=
 github.com/huandu/xstrings v1.3.2/go.mod h1:y5/lhBue+AyNmUVz9RLU9xbLR0o4KIIExikq4ovT0aE=
-github.com/iancoleman/strcase v0.2.0 h1:05I4QRnGpI0m37iZQRuskXh+w77mr6Z41lwQzuHLwW0=
-github.com/iancoleman/strcase v0.2.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/imdario/mergo v0.3.9/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
 github.com/imdario/mergo v0.3.11 h1:3tnifQM4i+fbajXKBHXWEH+KvNHqojZ778UH75j3bGA=
 github.com/imdario/mergo v0.3.11/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=
@@ -358,6 +355,8 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pty v1.1.1/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/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
@@ -581,10 +580,6 @@ github.com/tailscale/certstore v0.0.0-20210528134328-066c94b793d3 h1:fEubocuQkrl
 github.com/tailscale/certstore v0.0.0-20210528134328-066c94b793d3/go.mod h1:2P+hpOwd53e7JMX/L4f3VXkv1G+33ES6IWZSrkIeWNs=
 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/goupnp v1.0.1-0.20210804011211-c64d0f06ea05 h1:4chzWmimtJPxRs2O36yuGRW3f9SYV+bMTTvMBI0EKio=
-github.com/tailscale/goupnp v1.0.1-0.20210804011211-c64d0f06ea05/go.mod h1:PdCqy9JzfWMJf1H5UJW2ip33/d4YkoKN0r67yKH1mG8=
-github.com/tailscale/hujson v0.0.0-20200924210142-dde312d0d6a2 h1:reREUgl2FG+o7YCsrZB8XLjnuKv5hEIWtnOdAbRAXZI=
-github.com/tailscale/hujson v0.0.0-20200924210142-dde312d0d6a2/go.mod h1:STqf+YV0ADdzk4ejtXFsGqDpATP9JoL0OB+hiFQbkdE=
 github.com/tcnksm/go-httpstat v0.2.0 h1:rP7T5e5U2HfmOBmZzGgGZjBQ5/GluWUylujl0tJ04I0=
 github.com/tcnksm/go-httpstat v0.2.0/go.mod h1:s3JVJFtQxtBEBC9dwcdTTXS9xFnM3SXAZwPG41aurT8=
 github.com/tdakkota/asciicheck v0.0.0-20200416190851-d7f85be797a2/go.mod h1:yHp0ai0Z9gUljN3o0xMhYJnH/IcvkdTBOX2fmJ93JEM=
@@ -955,8 +950,8 @@ honnef.co/go/tools v0.0.1-2020.1.6/go.mod h1:pyyisuGw24ruLjrr1ddx39WE0y9OooInRzE
 honnef.co/go/tools v0.1.4 h1:SadWOkti5uVN1FAMgxn165+Mw00fuQKyk4Gyn/inxNQ=
 honnef.co/go/tools v0.1.4/go.mod h1:NgwopIslSNH47DimFoV78dnkksY2EFtX0ajyb3K/las=
 inet.af/netaddr v0.0.0-20210515010201-ad03edc7c841/go.mod h1:z0nx+Dh+7N7CC8V5ayHtHGpZpxLQZZxkIaaz6HN65Ls=
-inet.af/netaddr v0.0.0-20210721214506-ce7a8ad02cc1 h1:mxmfTV6kjXTlFqqFETnG9FQZzNFc6AKunZVAgQ3b7WA=
-inet.af/netaddr v0.0.0-20210721214506-ce7a8ad02cc1/go.mod h1:z0nx+Dh+7N7CC8V5ayHtHGpZpxLQZZxkIaaz6HN65Ls=
+inet.af/netaddr v0.0.0-20210602152128-50f8686885e3 h1:RlarOdsmOUCCvy7Xm1JchJIGuQsuKwD/Lo1bjYmfuQI=
+inet.af/netaddr v0.0.0-20210602152128-50f8686885e3/go.mod h1:z0nx+Dh+7N7CC8V5ayHtHGpZpxLQZZxkIaaz6HN65Ls=
 inet.af/netstack v0.0.0-20210622165351-29b14ebc044e h1:z11NK94NQcI3DA+a3pUC/2dRYTph1kPX6B0FnCaMDzk=
 inet.af/netstack v0.0.0-20210622165351-29b14ebc044e/go.mod h1:fG3G1dekmK8oDX3iVzt8c0zICLMLSN8SjdxbXVt0WjU=
 inet.af/peercred v0.0.0-20210318190834-4259e17bb763 h1:gPSJmmVzmdy4kHhlCMx912GdiUz3k/RzJGg0ADqy1dg=

hostinfo/hostinfo.go

@@ -27,7 +27,6 @@ const (
 	AWSLambda       = EnvType("lm")
 	Heroku          = EnvType("hr")
 	AzureAppService = EnvType("az")
-	AWSFargate      = EnvType("fg")
 )
 
 var envType atomic.Value // of EnvType
@@ -54,9 +53,6 @@ func getEnvType() EnvType {
 	if inAzureAppService() {
 		return AzureAppService
 	}
-	if inAWSFargate() {
-		return AWSFargate
-	}
 	return ""
 }
 
@@ -119,10 +115,3 @@ func inAzureAppService() bool {
 	}
 	return false
 }
-
-func inAWSFargate() bool {
-	if os.Getenv("AWS_EXECUTION_ENV") == "AWS_ECS_FARGATE" {
-		return true
-	}
-	return false
-}

ipn/ipnlocal/local.go

@@ -95,7 +95,7 @@ type LocalBackend struct {
 	serverURL             string           // tailcontrol URL
 	newDecompressor       func() (controlclient.Decompressor, error)
 
-	filterHash deephash.Sum
+	filterHash string
 
 	// The mutex protects the following elements.
 	mu             sync.Mutex
@@ -179,7 +179,6 @@ func NewLocalBackend(logf logger.Logf, logid string, store ipn.StateStore, e wge
 		gotPortPollRes: make(chan struct{}),
 	}
 	b.statusChanged = sync.NewCond(&b.statusLock)
-	b.e.SetStatusCallback(b.setWgengineStatus)
 
 	linkMon := e.GetLinkMonitor()
 	b.prevIfState = linkMon.InterfaceState()
@@ -215,15 +214,6 @@ func (b *LocalBackend) SetDirectFileRoot(dir string) {
 	b.directFileRoot = dir
 }
 
-// b.mu must be held.
-func (b *LocalBackend) maybePauseControlClientLocked() {
-	if b.cc == nil {
-		return
-	}
-	networkUp := b.prevIfState.AnyInterfaceUp()
-	b.cc.SetPaused((b.state == ipn.Stopped && b.netMap != nil) || !networkUp)
-}
-
 // 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) {
@@ -232,7 +222,11 @@ func (b *LocalBackend) linkChange(major bool, ifst *interfaces.State) {
 
 	hadPAC := b.prevIfState.HasPAC()
 	b.prevIfState = ifst
-	b.maybePauseControlClientLocked()
+
+	networkUp := ifst.AnyInterfaceUp()
+	if b.cc != nil {
+		go b.cc.SetPaused((b.state == ipn.Stopped && b.netMap != nil) || !networkUp)
+	}
 
 	// If the PAC-ness of the network changed, reconfig wireguard+route to
 	// add/remove subnets.
@@ -611,8 +605,8 @@ func (b *LocalBackend) setWgengineStatus(s *wgengine.Status, err error) {
 
 	if cc != nil {
 		cc.UpdateEndpoints(0, s.LocalAddrs)
-		b.stateMachine()
 	}
+	b.stateMachine()
 
 	b.statusLock.Lock()
 	b.statusChanged.Broadcast()
@@ -869,6 +863,7 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 	}
 
 	cc.SetStatusFunc(b.setClientStatus)
+	b.e.SetStatusCallback(b.setWgengineStatus)
 	b.e.SetNetInfoCallback(b.setNetInfo)
 
 	b.mu.Lock()
@@ -944,7 +939,7 @@ func (b *LocalBackend) updateFilter(netMap *netmap.NetworkMap, prefs *ipn.Prefs)
 	localNets, _ := localNetsB.IPSet()
 	logNets, _ := logNetsB.IPSet()
 
-	changed := deephash.Update(&b.filterHash, haveNetmap, addrs, packetFilter, localNets.Ranges(), logNets.Ranges(), shieldsUp)
+	changed := deephash.UpdateHash(&b.filterHash, haveNetmap, addrs, packetFilter, localNets.Ranges(), logNets.Ranges(), shieldsUp)
 	if !changed {
 		return
 	}
@@ -984,44 +979,6 @@ var removeFromDefaultRoute = []netaddr.IPPrefix{
 	tsaddr.TailscaleULARange(),
 }
 
-// internalAndExternalInterfaces splits interface routes into "internal"
-// and "external" sets. Internal routes are those of virtual ethernet
-// network interfaces used by guest VMs and containers, such as WSL and
-// Docker.
-//
-// Given that "internal" routes don't leave the device, we choose to
-// trust them more, allowing access to them when an Exit Node is enabled.
-func internalAndExternalInterfaces() (internal, external []netaddr.IPPrefix, err error) {
-	if err := interfaces.ForeachInterfaceAddress(func(iface interfaces.Interface, pfx netaddr.IPPrefix) {
-		if tsaddr.IsTailscaleIP(pfx.IP()) {
-			return
-		}
-		if pfx.IsSingleIP() {
-			return
-		}
-		if runtime.GOOS == "windows" {
-			// Windows Hyper-V prefixes all MAC addresses with 00:15:5d.
-			// https://docs.microsoft.com/en-us/troubleshoot/windows-server/virtualization/default-limit-256-dynamic-mac-addresses
-			//
-			// This includes WSL2 vEthernet.
-			// Importantly: by default WSL2 /etc/resolv.conf points to
-			// a stub resolver running on the host vEthernet IP.
-			// So enabling exit nodes with the default tailnet
-			// configuration breaks WSL2 DNS without this.
-			mac := iface.Interface.HardwareAddr
-			if len(mac) == 6 && mac[0] == 0x00 && mac[1] == 0x15 && mac[2] == 0x5d {
-				internal = append(internal, pfx)
-				return
-			}
-		}
-		external = append(external, pfx)
-	}); err != nil {
-		return nil, nil, err
-	}
-
-	return internal, external, nil
-}
-
 func interfaceRoutes() (ips *netaddr.IPSet, hostIPs []netaddr.IP, err error) {
 	var b netaddr.IPSetBuilder
 	if err := interfaces.ForeachInterfaceAddress(func(_ interfaces.Interface, pfx netaddr.IPPrefix) {
@@ -2157,21 +2114,18 @@ func (b *LocalBackend) routerConfig(cfg *wgcfg.Config, prefs *ipn.Prefs) *router
 		if !default6 {
 			rs.Routes = append(rs.Routes, ipv6Default)
 		}
-		internalIPs, externalIPs, err := internalAndExternalInterfaces()
-		if err != nil {
-			b.logf("failed to discover interface ips: %v", err)
-		}
 		if runtime.GOOS == "linux" || runtime.GOOS == "darwin" || runtime.GOOS == "windows" {
-			rs.LocalRoutes = internalIPs // unconditionally allow access to guest VM networks
+			// Only allow local lan access on linux machines for now.
+			ips, _, err := interfaceRoutes()
+			if err != nil {
+				b.logf("failed to discover interface ips: %v", err)
+			}
 			if prefs.ExitNodeAllowLANAccess {
-				rs.LocalRoutes = append(rs.LocalRoutes, externalIPs...)
-				if len(externalIPs) != 0 {
-					b.logf("allowing exit node access to internal IPs: %v", internalIPs)
-				}
+				rs.LocalRoutes = ips.Prefixes()
 			} else {
 				// Explicitly add routes to the local network so that we do not
 				// leak any traffic.
-				rs.Routes = append(rs.Routes, externalIPs...)
+				rs.Routes = append(rs.Routes, ips.Prefixes()...)
 			}
 		}
 	}
@@ -2200,18 +2154,6 @@ func applyPrefsToHostinfo(hi *tailcfg.Hostinfo, prefs *ipn.Prefs) {
 	}
 	if v := prefs.OSVersion; v != "" {
 		hi.OSVersion = v
-
-		// The Android app annotates when Google Play Services
-		// aren't available by tacking on a string to the
-		// OSVersion. Promote that to the Hostinfo.Package
-		// field instead, rather than adding a new pref, as
-		// this applyPrefsToHostinfo mechanism is mostly
-		// abused currently. TODO(bradfitz): instead let
-		// frontends update Hostinfo, without using Prefs.
-		if runtime.GOOS == "android" && strings.HasSuffix(v, " [nogoogle]") {
-			hi.Package = "nogoogle"
-			hi.OSVersion = strings.TrimSuffix(v, " [nogoogle]")
-		}
 	}
 	if m := prefs.DeviceModel; m != "" {
 		hi.DeviceModel = m
@@ -2231,7 +2173,9 @@ func (b *LocalBackend) enterState(newState ipn.State) {
 	oldState := b.state
 	b.state = newState
 	prefs := b.prefs
+	cc := b.cc
 	netMap := b.netMap
+	networkUp := b.prevIfState.AnyInterfaceUp()
 	activeLogin := b.activeLogin
 	authURL := b.authURL
 	if newState == ipn.Running {
@@ -2241,7 +2185,6 @@ func (b *LocalBackend) enterState(newState ipn.State) {
 		// Transitioning away from running.
 		b.closePeerAPIListenersLocked()
 	}
-	b.maybePauseControlClientLocked()
 	b.mu.Unlock()
 
 	if oldState == newState {
@@ -2252,6 +2195,10 @@ func (b *LocalBackend) enterState(newState ipn.State) {
 	health.SetIPNState(newState.String(), prefs.WantRunning)
 	b.send(ipn.Notify{State: &newState})
 
+	if cc != nil {
+		cc.SetPaused((newState == ipn.Stopped && netMap != nil) || !networkUp)
+	}
+
 	switch newState {
 	case ipn.NeedsLogin:
 		systemd.Status("Needs login: %s", authURL)
@@ -2512,7 +2459,6 @@ func (b *LocalBackend) setNetMapLocked(nm *netmap.NetworkMap) {
 		b.logf("active login: %v", login)
 		b.activeLogin = login
 	}
-	b.maybePauseControlClientLocked()
 
 	// Determine if file sharing is enabled
 	fs := hasCapability(nm, tailcfg.CapabilityFileSharing)
@@ -2784,18 +2730,17 @@ func (b *LocalBackend) CheckIPForwarding() error {
 		return nil
 	}
 
-	const suffix = "\nSubnet routes won't work without IP forwarding.\nSee https://tailscale.com/kb/1104/enable-ip-forwarding/"
 	for _, key := range keys {
 		bs, err := exec.Command("sysctl", "-n", key).Output()
 		if err != nil {
-			return fmt.Errorf("couldn't check %s (%v)%s", key, err, suffix)
+			return fmt.Errorf("couldn't check %s (%v).\nSubnet routes won't work without IP forwarding.", key, err)
 		}
 		on, err := strconv.ParseBool(string(bytes.TrimSpace(bs)))
 		if err != nil {
-			return fmt.Errorf("couldn't parse %s (%v)%s.", key, err, suffix)
+			return fmt.Errorf("couldn't parse %s (%v).\nSubnet routes won't work without IP forwarding.", key, err)
 		}
 		if !on {
-			return fmt.Errorf("%s is disabled.%s", key, suffix)
+			return fmt.Errorf("%s is disabled. Subnet routes won't work.", key)
 		}
 	}
 	return nil

ipn/ipnlocal/state_test.go

@@ -354,7 +354,7 @@ func TestStateMachine(t *testing.T) {
 	c.Assert(b.Start(ipn.Options{StateKey: ipn.GlobalDaemonStateKey}), qt.IsNil)
 	{
 		// BUG: strictly, it should pause, not unpause, here, since !WantRunning.
-		c.Assert([]string{"Shutdown", "unpause", "New", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"Shutdown", "New", "unpause"}, qt.DeepEquals, cc.getCalls())
 
 		nn := notifies.drain(2)
 		c.Assert(cc.getCalls(), qt.HasLen, 0)
@@ -389,7 +389,7 @@ func TestStateMachine(t *testing.T) {
 	url1 := "http://localhost:1/1"
 	cc.send(nil, url1, false, nil)
 	{
-		c.Assert(cc.getCalls(), qt.DeepEquals, []string{"unpause"})
+		c.Assert(cc.getCalls(), qt.DeepEquals, []string{})
 
 		// ...but backend eats that notification, because the user
 		// didn't explicitly request interactive login yet, and
@@ -414,7 +414,7 @@ func TestStateMachine(t *testing.T) {
 		// We're still not logged in so there's nothing we can do
 		// with it. (And empirically, it's providing an empty list
 		// of endpoints.)
-		c.Assert([]string{"UpdateEndpoints", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"UpdateEndpoints"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(nn[0].BrowseToURL, qt.Not(qt.IsNil))
 		c.Assert(url1, qt.Equals, *nn[0].BrowseToURL)
 	}
@@ -440,7 +440,7 @@ func TestStateMachine(t *testing.T) {
 	cc.send(nil, url2, false, nil)
 	{
 		// BUG: UpdateEndpoints again, this is getting silly.
-		c.Assert([]string{"UpdateEndpoints", "unpause", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"UpdateEndpoints"}, qt.DeepEquals, cc.getCalls())
 
 		// This time, backend should emit it to the UI right away,
 		// because the UI is anxiously awaiting a new URL to visit.
@@ -470,7 +470,7 @@ func TestStateMachine(t *testing.T) {
 		// wait until it gets into Starting.
 		// TODO: (Currently this test doesn't detect that bug, but
 		// it's visible in the logs)
-		c.Assert([]string{"unpause", "unpause", "UpdateEndpoints", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"unpause", "UpdateEndpoints"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(nn[0].LoginFinished, qt.Not(qt.IsNil))
 		c.Assert(nn[1].Prefs, qt.Not(qt.IsNil))
 		c.Assert(nn[2].State, qt.Not(qt.IsNil))
@@ -483,7 +483,7 @@ func TestStateMachine(t *testing.T) {
 	notifies.expect(1)
 	// BUG: the real controlclient sends LoginFinished with every
 	// notification while it's in StateAuthenticated, but not StateSynced.
-	// It should send it exactly once, or every time we're authenticated,
+	// We should send it exactly once, or every time we're authenticated,
 	// but the current code is brittle.
 	// (ie. I suspect it would be better to change false->true in send()
 	// below, and do the same in the real controlclient.)
@@ -492,7 +492,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(1)
-		c.Assert([]string{"unpause", "unpause", "UpdateEndpoints", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"unpause", "UpdateEndpoints"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(nn[0].State, qt.Not(qt.IsNil))
 		c.Assert(ipn.Starting, qt.Equals, *nn[0].State)
 	}
@@ -534,7 +534,7 @@ func TestStateMachine(t *testing.T) {
 		nn := notifies.drain(2)
 		// BUG: UpdateEndpoints isn't needed here.
 		// BUG: Login isn't needed here. We never logged out.
-		c.Assert([]string{"Login", "unpause", "UpdateEndpoints", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"Login", "unpause", "UpdateEndpoints"}, qt.DeepEquals, cc.getCalls())
 		// BUG: I would expect Prefs to change first, and state after.
 		c.Assert(nn[0].State, qt.Not(qt.IsNil))
 		c.Assert(nn[1].Prefs, qt.Not(qt.IsNil))
@@ -543,8 +543,7 @@ func TestStateMachine(t *testing.T) {
 	}
 
 	// Test the fast-path frontend reconnection.
-	// This one is very finicky, so we have to force State==Running
-	// or it won't use the fast path.
+	// This one is very finicky, so we have to force State==Running.
 	// TODO: actually get to State==Running, rather than cheating.
 	//  That'll require spinning up a fake DERP server and putting it in
 	//  the netmap.
@@ -571,7 +570,7 @@ func TestStateMachine(t *testing.T) {
 	b.Logout()
 	{
 		nn := notifies.drain(2)
-		c.Assert([]string{"pause", "StartLogout", "pause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"pause", "StartLogout"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(nn[0].State, qt.Not(qt.IsNil))
 		c.Assert(nn[1].Prefs, qt.Not(qt.IsNil))
 		c.Assert(ipn.Stopped, qt.Equals, *nn[0].State)
@@ -588,7 +587,7 @@ func TestStateMachine(t *testing.T) {
 	cc.send(nil, "", false, nil)
 	{
 		nn := notifies.drain(1)
-		c.Assert([]string{"unpause", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"unpause"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(nn[0].State, qt.Not(qt.IsNil))
 		c.Assert(ipn.NeedsLogin, qt.Equals, *nn[0].State)
 		c.Assert(b.Prefs().LoggedOut, qt.IsTrue)
@@ -604,7 +603,7 @@ func TestStateMachine(t *testing.T) {
 		notifies.drain(0)
 		// BUG: the backend has already called StartLogout, and we're
 		// still logged out. So it shouldn't call it again.
-		c.Assert([]string{"StartLogout", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"StartLogout"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(cc.getCalls(), qt.HasLen, 0)
 		c.Assert(b.Prefs().LoggedOut, qt.IsTrue)
 		c.Assert(b.Prefs().WantRunning, qt.IsFalse)
@@ -618,7 +617,8 @@ func TestStateMachine(t *testing.T) {
 	cc.send(nil, "", false, nil)
 	{
 		notifies.drain(0)
-		c.Assert(cc.getCalls(), qt.DeepEquals, []string{"unpause", "unpause"})
+		c.Assert(cc.getCalls(), qt.HasLen, 0)
+		c.Assert(cc.getCalls(), qt.HasLen, 0)
 		c.Assert(b.Prefs().LoggedOut, qt.IsTrue)
 		c.Assert(b.Prefs().WantRunning, qt.IsFalse)
 		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
@@ -632,7 +632,7 @@ func TestStateMachine(t *testing.T) {
 	// I guess, since that's supposed to be synchronous.
 	{
 		notifies.drain(0)
-		c.Assert([]string{"Logout", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"Logout"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(cc.getCalls(), qt.HasLen, 0)
 		c.Assert(b.Prefs().LoggedOut, qt.IsTrue)
 		c.Assert(b.Prefs().WantRunning, qt.IsFalse)
@@ -646,7 +646,8 @@ func TestStateMachine(t *testing.T) {
 	cc.send(nil, "", false, nil)
 	{
 		notifies.drain(0)
-		c.Assert(cc.getCalls(), qt.DeepEquals, []string{"unpause", "unpause"})
+		c.Assert(cc.getCalls(), qt.HasLen, 0)
+		c.Assert(cc.getCalls(), qt.HasLen, 0)
 		c.Assert(b.Prefs().LoggedOut, qt.IsTrue)
 		c.Assert(b.Prefs().WantRunning, qt.IsFalse)
 		c.Assert(ipn.NeedsLogin, qt.Equals, b.State())
@@ -677,7 +678,7 @@ func TestStateMachine(t *testing.T) {
 		// BUG: We already called Shutdown(), no need to do it again.
 		// BUG: Way too soon for UpdateEndpoints.
 		// BUG: don't unpause because we're not logged in.
-		c.Assert([]string{"Shutdown", "unpause", "New", "UpdateEndpoints", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"Shutdown", "New", "UpdateEndpoints", "unpause"}, qt.DeepEquals, cc.getCalls())
 
 		nn := notifies.drain(2)
 		c.Assert(cc.getCalls(), qt.HasLen, 0)
@@ -702,7 +703,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(3)
-		c.Assert([]string{"unpause", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"unpause"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(nn[0].LoginFinished, qt.Not(qt.IsNil))
 		c.Assert(nn[1].Prefs, qt.Not(qt.IsNil))
 		c.Assert(nn[2].State, qt.Not(qt.IsNil))
@@ -742,8 +743,9 @@ func TestStateMachine(t *testing.T) {
 		//  on startup, otherwise UIs can't show the node list, login
 		//  name, etc when in state ipn.Stopped.
 		//  Arguably they shouldn't try. But they currently do.
+		c.Assert([]string{"Shutdown", "New", "UpdateEndpoints", "Login", "unpause"}, qt.DeepEquals, cc.getCalls())
+
 		nn := notifies.drain(2)
-		c.Assert([]string{"Shutdown", "unpause", "New", "UpdateEndpoints", "Login", "unpause"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(cc.getCalls(), qt.HasLen, 0)
 		c.Assert(nn[0].Prefs, qt.Not(qt.IsNil))
 		c.Assert(nn[1].State, qt.Not(qt.IsNil))
@@ -752,25 +754,6 @@ func TestStateMachine(t *testing.T) {
 		c.Assert(ipn.Stopped, qt.Equals, *nn[1].State)
 	}
 
-	// When logged in but !WantRunning, ipn leaves us unpaused to retrieve
-	// the first netmap. Simulate that netmap being received, after which
-	// it should pause us, to avoid wasting CPU retrieving unnecessarily
-	// additional netmap updates.
-	//
-	// TODO: really the various GUIs and prefs should be refactored to
-	//  not require the netmap structure at all when starting while
-	//  !WantRunning. That would remove the need for this (or contacting
-	//  the control server at all when stopped).
-	t.Logf("\n\nStart4 -> netmap")
-	notifies.expect(0)
-	cc.send(nil, "", true, &netmap.NetworkMap{
-		MachineStatus: tailcfg.MachineAuthorized,
-	})
-	{
-		notifies.drain(0)
-		c.Assert([]string{"pause", "pause"}, qt.DeepEquals, cc.getCalls())
-	}
-
 	// Request connection.
 	// The state machine didn't call Login() earlier, so now it needs to.
 	t.Logf("\n\nWantRunning4 -> true")
@@ -797,7 +780,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(2)
-		c.Assert([]string{"pause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"unpause"}, qt.DeepEquals, cc.getCalls())
 		// BUG: I would expect Prefs to change first, and state after.
 		c.Assert(nn[0].State, qt.Not(qt.IsNil))
 		c.Assert(nn[1].Prefs, qt.Not(qt.IsNil))
@@ -807,27 +790,25 @@ func TestStateMachine(t *testing.T) {
 	// We want to try logging in as a different user, while Stopped.
 	// First, start the login process (without logging out first).
 	t.Logf("\n\nLoginDifferent")
-	notifies.expect(1)
+	notifies.expect(2)
 	b.StartLoginInteractive()
 	url3 := "http://localhost:1/3"
 	cc.send(nil, url3, false, nil)
 	{
-		nn := notifies.drain(1)
+		nn := notifies.drain(2)
 		// It might seem like WantRunning should switch to true here,
 		// but that would be risky since we already have a valid
 		// user account. It might try to reconnect to the old account
 		// before the new one is ready. So no change yet.
-		//
-		// Because the login hasn't yet completed, the old login
-		// is still valid, so it's correct that we stay paused.
-		c.Assert([]string{"Login", "pause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"Login", "unpause"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(nn[0].BrowseToURL, qt.Not(qt.IsNil))
+		c.Assert(nn[1].State, qt.Not(qt.IsNil))
 		c.Assert(*nn[0].BrowseToURL, qt.Equals, url3)
+		c.Assert(ipn.NeedsLogin, qt.Equals, *nn[1].State)
 	}
 
-	// Now, let's complete the interactive login, using a different
-	// user account than before. WantRunning changes to true after an
-	// interactive login, so we end up unpaused.
+	// Now, let's say the interactive login completed, using a different
+	// user account than before.
 	t.Logf("\n\nLoginDifferent URL visited")
 	notifies.expect(3)
 	cc.persist.LoginName = "user3"
@@ -836,13 +817,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(3)
-		// BUG: pause() being called here is a bad sign.
-		//  It means that either the state machine ran at least once
-		//  with the old netmap, or it ran with the new login+netmap
-		//  and !WantRunning. But since it's a fresh and successful
-		//  new login, WantRunning is true, so there was never a
-		//  reason to pause().
-		c.Assert([]string{"pause", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"unpause"}, qt.DeepEquals, cc.getCalls())
 		c.Assert(nn[0].LoginFinished, qt.Not(qt.IsNil))
 		c.Assert(nn[1].Prefs, qt.Not(qt.IsNil))
 		c.Assert(nn[2].State, qt.Not(qt.IsNil))
@@ -861,7 +836,7 @@ func TestStateMachine(t *testing.T) {
 	{
 		// NOTE: cc.Shutdown() is correct here, since we didn't call
 		// b.Shutdown() ourselves.
-		c.Assert([]string{"Shutdown", "unpause", "New", "UpdateEndpoints", "Login", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"Shutdown", "New", "UpdateEndpoints", "Login"}, qt.DeepEquals, cc.getCalls())
 
 		nn := notifies.drain(1)
 		c.Assert(cc.getCalls(), qt.HasLen, 0)
@@ -880,7 +855,7 @@ func TestStateMachine(t *testing.T) {
 	})
 	{
 		nn := notifies.drain(1)
-		c.Assert([]string{"unpause", "unpause"}, qt.DeepEquals, cc.getCalls())
+		c.Assert([]string{"unpause"}, qt.DeepEquals, cc.getCalls())
 		// NOTE: No LoginFinished message since no interactive
 		// login was needed.
 		c.Assert(nn[0].State, qt.Not(qt.IsNil))

ipn/ipnstate/ipnstate.go

@@ -20,7 +20,6 @@ import (
 
 	"inet.af/netaddr"
 	"tailscale.com/tailcfg"
-	"tailscale.com/tstime/mono"
 	"tailscale.com/types/key"
 	"tailscale.com/util/dnsname"
 )
@@ -91,7 +90,7 @@ type PeerStatus struct {
 	RxBytes       int64
 	TxBytes       int64
 	Created       time.Time // time registered with tailcontrol
-	LastWrite     mono.Time // time last packet sent
+	LastWrite     time.Time // time last packet sent
 	LastSeen      time.Time // last seen to tailcontrol
 	LastHandshake time.Time // with local wireguard
 	KeepAlive     bool
@@ -321,7 +320,7 @@ table tbody tr:nth-child(even) td { background-color: #f5f5f5; }
 	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 := mono.Now()
+	now := time.Now()
 
 	var peers []*PeerStatus
 	for _, peer := range st.Peers() {
@@ -379,7 +378,7 @@ table tbody tr:nth-child(even) td { background-color: #f5f5f5; }
 		f("<td>")
 
 		// TODO: let server report this active bool instead
-		active := !ps.LastWrite.IsZero() && mono.Since(ps.LastWrite) < 2*time.Minute
+		active := !ps.LastWrite.IsZero() && time.Since(ps.LastWrite) < 2*time.Minute
 		if active {
 			if ps.Relay != "" && ps.CurAddr == "" {
 				f("relay <b>%s</b>", html.EscapeString(ps.Relay))

ipn/localapi/localapi.go

@@ -266,7 +266,7 @@ func (h *Handler) serveFiles(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "file access denied", http.StatusForbidden)
 		return
 	}
-	suffix := strings.TrimPrefix(r.URL.EscapedPath(), "/localapi/v0/files/")
+	suffix := strings.TrimPrefix(r.URL.Path, "/localapi/v0/files/")
 	if suffix == "" {
 		if r.Method != "GET" {
 			http.Error(w, "want GET to list files", 400)

logpolicy/logpolicy.go

@@ -128,13 +128,6 @@ func (l logWriter) Write(buf []byte) (int, error) {
 // logsDir returns the directory to use for log configuration and
 // buffer storage.
 func logsDir(logf logger.Logf) string {
-	if d := os.Getenv("TS_LOGS_DIR"); d != "" {
-		fi, err := os.Stat(d)
-		if err == nil && fi.IsDir() {
-			return d
-		}
-	}
-
 	// STATE_DIRECTORY is set by systemd 240+ but we support older
 	// systems-d. For example, Ubuntu 18.04 (Bionic Beaver) is 237.
 	systemdStateDir := os.Getenv("STATE_DIRECTORY")
@@ -187,10 +180,6 @@ func runningUnderSystemd() bool {
 	return false
 }
 
-func redirectStderrToLogPanics() bool {
-	return runningUnderSystemd() || os.Getenv("TS_PLEASE_PANIC") != ""
-}
-
 // tryFixLogStateLocation is a temporary fixup for
 // https://github.com/tailscale/tailscale/issues/247 . We accidentally
 // wrote logging state files to /, and then later to $CACHE_DIRECTORY
@@ -439,14 +428,9 @@ func New(collection string) *Policy {
 		c.HTTPC = &http.Client{Transport: newLogtailTransport(u.Host)}
 	}
 
-	filchBuf, filchErr := filch.New(filepath.Join(dir, cmdName), filch.Options{
-		ReplaceStderr: redirectStderrToLogPanics(),
-	})
+	filchBuf, filchErr := filch.New(filepath.Join(dir, cmdName), filch.Options{})
 	if filchBuf != nil {
 		c.Buffer = filchBuf
-		if filchBuf.OrigStderr != nil {
-			c.Stderr = filchBuf.OrigStderr
-		}
 	}
 	lw := logtail.NewLogger(c, log.Printf)
 	log.SetFlags(0) // other logflags are set on console, not here

logtail/logtail.go

@@ -118,10 +118,9 @@ type Logger struct {
 	bo             *backoff.Backoff
 	zstdEncoder    Encoder
 	uploadCancel   func()
-	explainedRaw   bool
 
 	shutdownStart chan struct{} // closed when shutdown begins
-	shutdownDone  chan struct{} // closed when shutdown complete
+	shutdownDone  chan struct{} // closd when shutdown complete
 }
 
 // SetVerbosityLevel controls the verbosity level that should be
@@ -231,14 +230,6 @@ func (l *Logger) drainPending() (res []byte) {
 			// outside of the logtail logger. Encode it.
 			// Do not add a client time, as it could have been
 			// been written a long time ago.
-			if !l.explainedRaw {
-				fmt.Fprintf(l.stderr, "RAW-STDERR: ***\n")
-				fmt.Fprintf(l.stderr, "RAW-STDERR: *** Lines prefixed with RAW-STDERR below bypassed logtail and probably come from a previous run of the program\n")
-				fmt.Fprintf(l.stderr, "RAW-STDERR: ***\n")
-				fmt.Fprintf(l.stderr, "RAW-STDERR:\n")
-				l.explainedRaw = true
-			}
-			fmt.Fprintf(l.stderr, "RAW-STDERR: %s", b)
 			b = l.encodeText(b, true)
 		}
 

net/dns/config.go

@@ -5,12 +5,9 @@
 package dns
 
 import (
-	"bufio"
-	"fmt"
 	"sort"
 
 	"inet.af/netaddr"
-	"tailscale.com/net/dns/resolver"
 	"tailscale.com/util/dnsname"
 )
 
@@ -41,20 +38,6 @@ type Config struct {
 	Hosts map[dnsname.FQDN][]netaddr.IP
 }
 
-// WriteToBufioWriter write a debug version of c for logs to w, omitting
-// spammy stuff like *.arpa entries and replacing it with a total count.
-func (c *Config) WriteToBufioWriter(w *bufio.Writer) {
-	w.WriteString("{DefaultResolvers:")
-	resolver.WriteIPPorts(w, c.DefaultResolvers)
-
-	w.WriteString(" Routes:")
-	resolver.WriteRoutes(w, c.Routes)
-
-	fmt.Fprintf(w, " SearchDomains:%v", c.SearchDomains)
-	fmt.Fprintf(w, " Hosts:%v", len(c.Hosts))
-	w.WriteString("}")
-}
-
 // needsAnyResolvers reports whether c requires a resolver to be set
 // at the OS level.
 func (c Config) needsOSResolver() bool {

net/dns/ini.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build windows
-
 package dns
 
 import (

net/dns/ini_test.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build windows
-
 package dns
 
 import (

net/dns/manager.go

@@ -5,7 +5,6 @@
 package dns
 
 import (
-	"bufio"
 	"runtime"
 	"time"
 
@@ -51,18 +50,14 @@ func NewManager(logf logger.Logf, oscfg OSConfigurator, linkMon *monitor.Mon, li
 }
 
 func (m *Manager) Set(cfg Config) error {
-	m.logf("Set: %v", logger.ArgWriter(func(w *bufio.Writer) {
-		cfg.WriteToBufioWriter(w)
-	}))
+	m.logf("Set: %+v", cfg)
 
 	rcfg, ocfg, err := m.compileConfig(cfg)
 	if err != nil {
 		return err
 	}
 
-	m.logf("Resolvercfg: %v", logger.ArgWriter(func(w *bufio.Writer) {
-		rcfg.WriteToBufioWriter(w)
-	}))
+	m.logf("Resolvercfg: %+v", rcfg)
 	m.logf("OScfg: %+v", ocfg)
 
 	if err := m.resolver.SetConfig(rcfg); err != nil {

net/dns/manager_windows.go

@@ -293,7 +293,7 @@ func (m windowsManager) SetDNS(cfg OSConfig) error {
 		}
 
 		t0 = time.Now()
-		m.logf("running ipconfig /flushdns ...")
+		m.logf("running ipconfig /registerdns ...")
 		cmd = exec.Command("ipconfig", "/flushdns")
 		cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
 		err = cmd.Run()

net/dns/resolver/doh_test.go

@@ -1,98 +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 resolver
-
-import (
-	"context"
-	"flag"
-	"net/http"
-	"testing"
-
-	"golang.org/x/net/dns/dnsmessage"
-)
-
-var testDoH = flag.Bool("test-doh", false, "do real DoH tests against the network")
-
-const someDNSID = 123 // something non-zero as a test; in violation of spec's SHOULD of 0
-
-func someDNSQuestion(t testing.TB) []byte {
-	b := dnsmessage.NewBuilder(nil, dnsmessage.Header{
-		OpCode:           0, // query
-		RecursionDesired: true,
-		ID:               someDNSID,
-	})
-	b.StartQuestions() // err
-	b.Question(dnsmessage.Question{
-		Name:  dnsmessage.MustNewName("tailscale.com."),
-		Type:  dnsmessage.TypeA,
-		Class: dnsmessage.ClassINET,
-	})
-	msg, err := b.Finish()
-	if err != nil {
-		t.Fatal(err)
-	}
-	return msg
-}
-
-func TestDoH(t *testing.T) {
-	if !*testDoH {
-		t.Skip("skipping manual test without --test-doh flag")
-	}
-	if len(knownDoH) == 0 {
-		t.Fatal("no known DoH")
-	}
-
-	f := &forwarder{
-		dohSem: make(chan struct{}, 10),
-	}
-
-	for ip := range knownDoH {
-		t.Run(ip.String(), func(t *testing.T) {
-			urlBase, c, ok := f.getDoHClient(ip)
-			if !ok {
-				t.Fatal("expected DoH")
-			}
-			res, err := f.sendDoH(context.Background(), urlBase, c, someDNSQuestion(t))
-			if err != nil {
-				t.Fatal(err)
-			}
-			c.Transport.(*http.Transport).CloseIdleConnections()
-
-			var p dnsmessage.Parser
-			h, err := p.Start(res)
-			if err != nil {
-				t.Fatal(err)
-			}
-			if h.ID != someDNSID {
-				t.Errorf("response DNS ID = %v; want %v", h.ID, someDNSID)
-			}
-
-			p.SkipAllQuestions()
-			aa, err := p.AllAnswers()
-			if err != nil {
-				t.Fatal(err)
-			}
-			if len(aa) == 0 {
-				t.Fatal("no answers")
-			}
-			for _, r := range aa {
-				t.Logf("got: %v", r.GoString())
-			}
-		})
-	}
-}
-
-func TestDoHV6Fallback(t *testing.T) {
-	for ip, base := range knownDoH {
-		if ip.Is4() {
-			ip6, ok := dohV6(base)
-			if !ok {
-				t.Errorf("no v6 DoH known for %v", ip)
-			} else if !ip6.Is6() {
-				t.Errorf("dohV6(%q) returned non-v6 address %v", base, ip6)
-			}
-		}
-	}
-}

net/dns/resolver/forwarder.go

@@ -9,22 +9,15 @@ import (
 	"context"
 	"encoding/binary"
 	"errors"
-	"fmt"
 	"hash/crc32"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"net"
-	"net/http"
-	"runtime"
-	"sort"
-	"strings"
 	"sync"
 	"time"
 
 	dns "golang.org/x/net/dns/dnsmessage"
 	"inet.af/netaddr"
-	"tailscale.com/net/netns"
 	"tailscale.com/types/logger"
 	"tailscale.com/util/dnsname"
 	"tailscale.com/wgengine/monitor"
@@ -36,16 +29,6 @@ const headerBytes = 12
 const (
 	// responseTimeout is the maximal amount of time to wait for a DNS response.
 	responseTimeout = 5 * time.Second
-
-	// dohTransportTimeout is how long to keep idle HTTP
-	// connections open to DNS-over-HTTPs servers. This is pretty
-	// arbitrary.
-	dohTransportTimeout = 30 * time.Second
-
-	// wellKnownHostBackupDelay is how long to artificially delay upstream
-	// DNS queries to the "fallback" DNS server IP for a known provider
-	// (e.g. how long to wait to query Google's 8.8.4.4 after 8.8.8.8).
-	wellKnownHostBackupDelay = 200 * time.Millisecond
 )
 
 var errNoUpstreams = errors.New("upstream nameservers not set")
@@ -125,7 +108,6 @@ func clampEDNSSize(packet []byte, maxSize uint16) {
 		return
 	}
 
-	// https://datatracker.ietf.org/doc/html/rfc6891#section-6.1.2
 	opt := packet[len(packet)-optFixedBytes:]
 
 	if opt[0] != 0 {
@@ -142,8 +124,8 @@ func clampEDNSSize(packet []byte, maxSize uint16) {
 		// Be conservative and don't touch unknown versions.
 		return
 	}
-	// Ignore flags in opt[6:9]
-	if binary.BigEndian.Uint16(opt[9:11]) != 0 {
+	// Ignore flags in opt[7:9]
+	if binary.BigEndian.Uint16(opt[10:12]) != 0 {
 		// RDLEN must be 0 (no variable length data). We're at the end of the
 		// packet so this should be 0 anyway)..
 		return
@@ -159,20 +141,7 @@ func clampEDNSSize(packet []byte, maxSize uint16) {
 
 type route struct {
 	Suffix    dnsname.FQDN
-	Resolvers []resolverAndDelay
-}
-
-// resolverAndDelay is an upstream DNS resolver and a delay for how
-// long to wait before querying it.
-type resolverAndDelay struct {
-	// ipp is the upstream resolver.
-	ipp netaddr.IPPort
-
-	// startDelay is an amount to delay this resolver at
-	// start. It's used when, say, there are four Google or
-	// Cloudflare DNS IPs (two IPv4 + two IPv6) and we don't want
-	// to race all four at once.
-	startDelay time.Duration
+	Resolvers []netaddr.IPPort
 }
 
 // forwarder forwards DNS packets to a number of upstream nameservers.
@@ -180,7 +149,6 @@ type forwarder struct {
 	logf    logger.Logf
 	linkMon *monitor.Mon
 	linkSel ForwardLinkSelector
-	dohSem  chan struct{}
 
 	ctx       context.Context    // good until Close
 	ctxCancel context.CancelFunc // closes ctx
@@ -190,8 +158,6 @@ type forwarder struct {
 
 	mu sync.Mutex // guards following
 
-	dohClient map[netaddr.IP]*http.Client
-
 	// routes are per-suffix resolvers to use, with
 	// the most specific routes first.
 	routes []route
@@ -202,18 +168,11 @@ func init() {
 }
 
 func newForwarder(logf logger.Logf, responses chan packet, linkMon *monitor.Mon, linkSel ForwardLinkSelector) *forwarder {
-	maxDoHInFlight := 1000 // effectively unlimited
-	if runtime.GOOS == "ios" {
-		// No HTTP/2 on iOS yet (for size reasons), so DoH is
-		// pricier.
-		maxDoHInFlight = 10
-	}
 	f := &forwarder{
 		logf:      logger.WithPrefix(logf, "forward: "),
 		linkMon:   linkMon,
 		linkSel:   linkSel,
 		responses: responses,
-		dohSem:    make(chan struct{}, maxDoHInFlight),
 	}
 	f.ctx, f.ctxCancel = context.WithCancel(context.Background())
 	return f
@@ -224,84 +183,7 @@ func (f *forwarder) Close() error {
 	return nil
 }
 
-// resolversWithDelays maps from a set of DNS server ip:ports (currently
-// the port is always 53) to a slice of a type that included a
-// startDelay. So if ipps contains e.g. four Google DNS IPs (two IPv4
-// + twoIPv6), this function partition adds delays to some.
-func resolversWithDelays(ipps []netaddr.IPPort) []resolverAndDelay {
-	type hostAndFam struct {
-		host string // some arbitrary string representing DNS host (currently the DoH base)
-		bits uint8  // either 32 or 128 for IPv4 vs IPv6s address family
-	}
-
-	// Track how many of each known resolver host are in the list,
-	// per address family.
-	total := map[hostAndFam]int{}
-
-	rr := make([]resolverAndDelay, len(ipps))
-	for _, ipp := range ipps {
-		ip := ipp.IP()
-		if host, ok := knownDoH[ip]; ok {
-			total[hostAndFam{host, ip.BitLen()}]++
-		}
-	}
-
-	done := map[hostAndFam]int{}
-	for i, ipp := range ipps {
-		ip := ipp.IP()
-		var startDelay time.Duration
-		if host, ok := knownDoH[ip]; ok {
-			key4 := hostAndFam{host, 32}
-			key6 := hostAndFam{host, 128}
-			switch {
-			case ip.Is4():
-				if done[key4] > 0 {
-					startDelay += wellKnownHostBackupDelay
-				}
-			case ip.Is6():
-				total4 := total[key4]
-				if total4 >= 2 {
-					// If we have two IPv4 IPs of the same provider
-					// already in the set, delay the IPv6 queries
-					// until halfway through the timeout (so wait
-					// 2.5 seconds). Even the network is IPv6-only,
-					// the DoH dialer will fallback to IPv6
-					// immediately anyway.
-					startDelay = responseTimeout / 2
-				} else if total4 == 1 {
-					startDelay += wellKnownHostBackupDelay
-				}
-				if done[key6] > 0 {
-					startDelay += wellKnownHostBackupDelay
-				}
-			}
-			done[hostAndFam{host, ip.BitLen()}]++
-		}
-		rr[i] = resolverAndDelay{
-			ipp:        ipp,
-			startDelay: startDelay,
-		}
-	}
-	return rr
-}
-
-// setRoutes sets the routes to use for DNS forwarding. It's called by
-// Resolver.SetConfig on reconfig.
-//
-// The memory referenced by routesBySuffix should not be modified.
-func (f *forwarder) setRoutes(routesBySuffix map[dnsname.FQDN][]netaddr.IPPort) {
-	routes := make([]route, 0, len(routesBySuffix))
-	for suffix, ipps := range routesBySuffix {
-		routes = append(routes, route{
-			Suffix:    suffix,
-			Resolvers: resolversWithDelays(ipps),
-		})
-	}
-	// Sort from longest prefix to shortest.
-	sort.Slice(routes, func(i, j int) bool {
-		return routes[i].Suffix.NumLabels() > routes[j].Suffix.NumLabels()
-	})
-
+func (f *forwarder) setRoutes(routes []route) {
 	f.mu.Lock()
 	defer f.mu.Unlock()
 	f.routes = routes
@@ -328,104 +210,21 @@ func (f *forwarder) packetListener(ip netaddr.IP) (packetListener, error) {
 	return lc, nil
 }
 
-func (f *forwarder) getDoHClient(ip netaddr.IP) (urlBase string, c *http.Client, ok bool) {
-	urlBase, ok = knownDoH[ip]
-	if !ok {
-		return
-	}
-	f.mu.Lock()
-	defer f.mu.Unlock()
-	if c, ok := f.dohClient[ip]; ok {
-		return urlBase, c, true
-	}
-	if f.dohClient == nil {
-		f.dohClient = map[netaddr.IP]*http.Client{}
-	}
-	nsDialer := netns.NewDialer()
-	c = &http.Client{
-		Transport: &http.Transport{
-			IdleConnTimeout: dohTransportTimeout,
-			DialContext: func(ctx context.Context, netw, addr string) (net.Conn, error) {
-				if !strings.HasPrefix(netw, "tcp") {
-					return nil, fmt.Errorf("unexpected network %q", netw)
-				}
-				c, err := nsDialer.DialContext(ctx, "tcp", net.JoinHostPort(ip.String(), "443"))
-				// If v4 failed, try an equivalent v6 also in the time remaining.
-				if err != nil && ctx.Err() == nil {
-					if ip6, ok := dohV6(urlBase); ok && ip.Is4() {
-						if c6, err := nsDialer.DialContext(ctx, "tcp", net.JoinHostPort(ip6.String(), "443")); err == nil {
-							return c6, nil
-						}
-					}
-				}
-				return c, err
-			},
-		},
-	}
-	f.dohClient[ip] = c
-	return urlBase, c, true
-}
-
-const dohType = "application/dns-message"
-
-func (f *forwarder) releaseDoHSem() { <-f.dohSem }
-
-func (f *forwarder) sendDoH(ctx context.Context, urlBase string, c *http.Client, packet []byte) ([]byte, error) {
-	// Bound the number of HTTP requests in flight. This primarily
-	// matters for iOS where we're very memory constrained and
-	// HTTP requests are heavier on iOS where we don't include
-	// HTTP/2 for binary size reasons (as binaries on iOS linked
-	// with Go code cost memory proportional to the binary size,
-	// for reasons not fully understood).
-	select {
-	case f.dohSem <- struct{}{}:
-	case <-ctx.Done():
-		return nil, ctx.Err()
-	}
-	defer f.releaseDoHSem()
-
-	req, err := http.NewRequestWithContext(ctx, "POST", urlBase, bytes.NewReader(packet))
-	if err != nil {
-		return nil, err
-	}
-	req.Header.Set("Content-Type", dohType)
-	// Note: we don't currently set the Accept header (which is
-	// only a SHOULD in the spec) as iOS doesn't use HTTP/2 and
-	// we'd rather save a few bytes on outgoing requests when
-	// empirically no provider cares about the Accept header's
-	// absence.
-
-	hres, err := c.Do(req)
-	if err != nil {
-		return nil, err
-	}
-	defer hres.Body.Close()
-	if hres.StatusCode != 200 {
-		return nil, errors.New(hres.Status)
-	}
-	if ct := hres.Header.Get("Content-Type"); ct != dohType {
-		return nil, fmt.Errorf("unexpected response Content-Type %q", ct)
-	}
-	return ioutil.ReadAll(hres.Body)
-}
-
 // send sends packet to dst. It is best effort.
 //
 // send expects the reply to have the same txid as txidOut.
 //
-func (f *forwarder) send(ctx context.Context, fq *forwardQuery, dst netaddr.IPPort) ([]byte, error) {
-	ip := dst.IP()
+// The provided closeOnCtxDone lets send register values to Close if
+// the caller's ctx expires. This avoids send from allocating its own
+// waiting goroutine to interrupt the ReadFrom, as memory is tight on
+// iOS and we want the number of pending DNS lookups to be bursty
+// without too much associated goroutine/memory cost.
+func (f *forwarder) send(ctx context.Context, txidOut txid, closeOnCtxDone *closePool, packet []byte, dst netaddr.IPPort) ([]byte, error) {
+	// TODO(bradfitz): if dst.IP is 8.8.8.8 or 8.8.4.4 or 1.1.1.1, etc, or
+	// something dynamically probed earlier to support DoH or DoT,
+	// do that here instead.
 
-	// Upgrade known DNS IPs to DoH (DNS-over-HTTPs).
-	if urlBase, dc, ok := f.getDoHClient(ip); ok {
-		res, err := f.sendDoH(ctx, urlBase, dc, fq.packet)
-		if err == nil || ctx.Err() != nil {
-			return res, err
-		}
-		f.logf("DoH error from %v: %v", ip, err)
-	}
-
-	ln, err := f.packetListener(ip)
+	ln, err := f.packetListener(dst.IP())
 	if err != nil {
 		return nil, err
 	}
@@ -436,10 +235,10 @@ func (f *forwarder) send(ctx context.Context, fq *forwardQuery, dst netaddr.IPPo
 	}
 	defer conn.Close()
 
-	fq.closeOnCtxDone.Add(conn)
-	defer fq.closeOnCtxDone.Remove(conn)
+	closeOnCtxDone.Add(conn)
+	defer closeOnCtxDone.Remove(conn)
 
-	if _, err := conn.WriteTo(fq.packet, dst.UDPAddr()); err != nil {
+	if _, err := conn.WriteTo(packet, dst.UDPAddr()); err != nil {
 		if err := ctx.Err(); err != nil {
 			return nil, err
 		}
@@ -468,7 +267,7 @@ func (f *forwarder) send(ctx context.Context, fq *forwardQuery, dst netaddr.IPPo
 	}
 	out = out[:n]
 	txid := getTxID(out)
-	if txid != fq.txid {
+	if txid != txidOut {
 		return nil, errors.New("txid doesn't match")
 	}
 
@@ -491,7 +290,7 @@ func (f *forwarder) send(ctx context.Context, fq *forwardQuery, dst netaddr.IPPo
 }
 
 // resolvers returns the resolvers to use for domain.
-func (f *forwarder) resolvers(domain dnsname.FQDN) []resolverAndDelay {
+func (f *forwarder) resolvers(domain dnsname.FQDN) []netaddr.IPPort {
 	f.mu.Lock()
 	routes := f.routes
 	f.mu.Unlock()
@@ -503,30 +302,6 @@ func (f *forwarder) resolvers(domain dnsname.FQDN) []resolverAndDelay {
 	return nil
 }
 
-// forwardQuery is information and state about a forwarded DNS query that's
-// being sent to 1 or more upstreams.
-//
-// In the case of racing against multiple equivalent upstreams
-// (e.g. Google or CloudFlare's 4 DNS IPs: 2 IPv4 + 2 IPv6), this type
-// handles racing them more intelligently than just blasting away 4
-// queries at once.
-type forwardQuery struct {
-	txid   txid
-	packet []byte
-
-	// closeOnCtxDone lets send register values to Close if the
-	// caller's ctx expires. This avoids send from allocating its
-	// own waiting goroutine to interrupt the ReadFrom, as memory
-	// is tight on iOS and we want the number of pending DNS
-	// lookups to be bursty without too much associated
-	// goroutine/memory cost.
-	closeOnCtxDone *closePool
-
-	// TODO(bradfitz): add race delay state:
-	// mu sync.Mutex
-	// ...
-}
-
 // forward forwards the query to all upstream nameservers and returns the first response.
 func (f *forwarder) forward(query packet) error {
 	domain, err := nameFromQuery(query.bs)
@@ -534,6 +309,7 @@ func (f *forwarder) forward(query packet) error {
 		return err
 	}
 
+	txid := getTxID(query.bs)
 	clampEDNSSize(query.bs, maxResponseBytes)
 
 	resolvers := f.resolvers(domain)
@@ -541,12 +317,8 @@ func (f *forwarder) forward(query packet) error {
 		return errNoUpstreams
 	}
 
-	fq := &forwardQuery{
-		txid:           getTxID(query.bs),
-		packet:         query.bs,
-		closeOnCtxDone: new(closePool),
-	}
-	defer fq.closeOnCtxDone.Close()
+	closeOnCtxDone := new(closePool)
+	defer closeOnCtxDone.Close()
 
 	ctx, cancel := context.WithTimeout(f.ctx, responseTimeout)
 	defer cancel()
@@ -557,18 +329,9 @@ func (f *forwarder) forward(query packet) error {
 		firstErr error
 	)
 
-	for _, rr := range resolvers {
-		go func(rr resolverAndDelay) {
-			if rr.startDelay > 0 {
-				timer := time.NewTimer(rr.startDelay)
-				select {
-				case <-timer.C:
-				case <-ctx.Done():
-					timer.Stop()
-					return
-				}
-			}
-			resb, err := f.send(ctx, fq, rr.ipp)
+	for _, ipp := range resolvers {
+		go func(ipp netaddr.IPPort) {
+			resb, err := f.send(ctx, txid, closeOnCtxDone, query.bs, ipp)
 			if err != nil {
 				mu.Lock()
 				defer mu.Unlock()
@@ -581,7 +344,7 @@ func (f *forwarder) forward(query packet) error {
 			case resc <- resb:
 			default:
 			}
-		}(rr)
+		}(ipp)
 	}
 
 	select {
@@ -669,63 +432,3 @@ func (p *closePool) Close() error {
 	}
 	return nil
 }
-
-var knownDoH = map[netaddr.IP]string{}
-
-var dohIPsOfBase = map[string][]netaddr.IP{}
-
-func addDoH(ipStr, base string) {
-	ip := netaddr.MustParseIP(ipStr)
-	knownDoH[ip] = base
-	dohIPsOfBase[base] = append(dohIPsOfBase[base], ip)
-}
-
-func dohV6(base string) (ip netaddr.IP, ok bool) {
-	for _, ip := range dohIPsOfBase[base] {
-		if ip.Is6() {
-			return ip, true
-		}
-	}
-	return ip, false
-}
-
-func init() {
-	// Cloudflare
-	addDoH("1.1.1.1", "https://cloudflare-dns.com/dns-query")
-	addDoH("1.0.0.1", "https://cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1111", "https://cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1001", "https://cloudflare-dns.com/dns-query")
-
-	// Cloudflare -Malware
-	addDoH("1.1.1.2", "https://security.cloudflare-dns.com/dns-query")
-	addDoH("1.0.0.2", "https://security.cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1112", "https://security.cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1002", "https://security.cloudflare-dns.com/dns-query")
-
-	// Cloudflare -Malware -Adult
-	addDoH("1.1.1.3", "https://family.cloudflare-dns.com/dns-query")
-	addDoH("1.0.0.3", "https://family.cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1113", "https://family.cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1003", "https://family.cloudflare-dns.com/dns-query")
-
-	// Google
-	addDoH("8.8.8.8", "https://dns.google/dns-query")
-	addDoH("8.8.4.4", "https://dns.google/dns-query")
-	addDoH("2001:4860:4860::8888", "https://dns.google/dns-query")
-	addDoH("2001:4860:4860::8844", "https://dns.google/dns-query")
-
-	// OpenDNS
-	// TODO(bradfitz): OpenDNS is unique amongst this current set in that
-	// its DoH DNS names resolve to different IPs than its normal DNS
-	// IPs. Support that later. For now we assume that they're the same.
-	// addDoH("208.67.222.222", "https://doh.opendns.com/dns-query")
-	// addDoH("208.67.220.220", "https://doh.opendns.com/dns-query")
-	// addDoH("208.67.222.123", "https://doh.familyshield.opendns.com/dns-query")
-	// addDoH("208.67.220.123", "https://doh.familyshield.opendns.com/dns-query")
-
-	// Quad9
-	addDoH("9.9.9.9", "https://dns.quad9.net/dns-query")
-	addDoH("149.112.112.112", "https://dns.quad9.net/dns-query")
-	addDoH("2620:fe::fe", "https://dns.quad9.net/dns-query")
-	addDoH("2620:fe::fe:9", "https://dns.quad9.net/dns-query")
-}

net/dns/resolver/forwarder_test.go

@@ -1,90 +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 resolver
-
-import (
-	"fmt"
-	"reflect"
-	"strings"
-	"testing"
-	"time"
-
-	"inet.af/netaddr"
-)
-
-func (rr resolverAndDelay) String() string {
-	return fmt.Sprintf("%v+%v", rr.ipp, rr.startDelay)
-}
-
-func TestResolversWithDelays(t *testing.T) {
-	// query
-	q := func(ss ...string) (ipps []netaddr.IPPort) {
-		for _, s := range ss {
-			ipps = append(ipps, netaddr.MustParseIPPort(s))
-		}
-		return
-	}
-	// output
-	o := func(ss ...string) (rr []resolverAndDelay) {
-		for _, s := range ss {
-			var d time.Duration
-			if i := strings.Index(s, "+"); i != -1 {
-				var err error
-				d, err = time.ParseDuration(s[i+1:])
-				if err != nil {
-					panic(fmt.Sprintf("parsing duration in %q: %v", s, err))
-				}
-				s = s[:i]
-			}
-			rr = append(rr, resolverAndDelay{
-				ipp:        netaddr.MustParseIPPort(s),
-				startDelay: d,
-			})
-		}
-		return
-	}
-
-	tests := []struct {
-		name string
-		in   []netaddr.IPPort
-		want []resolverAndDelay
-	}{
-		{
-			name: "unknown-no-delays",
-			in:   q("1.2.3.4:53", "2.3.4.5:53"),
-			want: o("1.2.3.4:53", "2.3.4.5:53"),
-		},
-		{
-			name: "google-all-ipv4",
-			in:   q("8.8.8.8:53", "8.8.4.4:53"),
-			want: o("8.8.8.8:53", "8.8.4.4:53+200ms"),
-		},
-		{
-			name: "google-only-ipv6",
-			in:   q("[2001:4860:4860::8888]:53", "[2001:4860:4860::8844]:53"),
-			want: o("[2001:4860:4860::8888]:53", "[2001:4860:4860::8844]:53+200ms"),
-		},
-		{
-			name: "google-all-four",
-			in:   q("8.8.8.8:53", "8.8.4.4:53", "[2001:4860:4860::8888]:53", "[2001:4860:4860::8844]:53"),
-			want: o("8.8.8.8:53", "8.8.4.4:53+200ms", "[2001:4860:4860::8888]:53+2.5s", "[2001:4860:4860::8844]:53+2.7s"),
-		},
-		{
-			name: "quad9-one-v4-one-v6",
-			in:   q("9.9.9.9:53", "[2620:fe::fe]:53"),
-			want: o("9.9.9.9:53", "[2620:fe::fe]:53+200ms"),
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got := resolversWithDelays(tt.in)
-			if !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("got %v; want %v", got, tt.want)
-			}
-		})
-	}
-
-}

net/dns/resolver/tsdns.go

@@ -7,10 +7,8 @@
 package resolver
 
 import (
-	"bufio"
 	"encoding/hex"
 	"errors"
-	"fmt"
 	"runtime"
 	"sort"
 	"strings"
@@ -81,74 +79,6 @@ type Config struct {
 	LocalDomains []dnsname.FQDN
 }
 
-// WriteToBufioWriter write a debug version of c for logs to w, omitting
-// spammy stuff like *.arpa entries and replacing it with a total count.
-func (c *Config) WriteToBufioWriter(w *bufio.Writer) {
-	w.WriteString("{Routes:")
-	WriteRoutes(w, c.Routes)
-	fmt.Fprintf(w, " Hosts:%v LocalDomains:[", len(c.Hosts))
-	space := false
-	arpa := 0
-	for _, d := range c.LocalDomains {
-		if strings.HasSuffix(string(d), ".arpa.") {
-			arpa++
-			continue
-		}
-		if space {
-			w.WriteByte(' ')
-		}
-		w.WriteString(string(d))
-		space = true
-	}
-	w.WriteString("]")
-	if arpa > 0 {
-		fmt.Fprintf(w, "+%darpa", arpa)
-	}
-	w.WriteString("}")
-}
-
-// WriteIPPorts writes vv to w.
-func WriteIPPorts(w *bufio.Writer, vv []netaddr.IPPort) {
-	w.WriteByte('[')
-	var b []byte
-	for i, v := range vv {
-		if i > 0 {
-			w.WriteByte(' ')
-		}
-		b = v.AppendTo(b[:0])
-		w.Write(b)
-	}
-	w.WriteByte(']')
-}
-
-// WriteRoutes writes routes to w, omitting *.arpa routes and instead
-// summarizing how many of them there were.
-func WriteRoutes(w *bufio.Writer, routes map[dnsname.FQDN][]netaddr.IPPort) {
-	var kk []dnsname.FQDN
-	arpa := 0
-	for k := range routes {
-		if strings.HasSuffix(string(k), ".arpa.") {
-			arpa++
-			continue
-		}
-		kk = append(kk, k)
-	}
-	sort.Slice(kk, func(i, j int) bool { return kk[i] < kk[j] })
-	w.WriteByte('{')
-	for i, k := range kk {
-		if i > 0 {
-			w.WriteByte(' ')
-		}
-		w.WriteString(string(k))
-		w.WriteByte(':')
-		WriteIPPorts(w, routes[k])
-	}
-	w.WriteByte('}')
-	if arpa > 0 {
-		fmt.Fprintf(w, "+%darpa", arpa)
-	}
-}
-
 // Resolver is a DNS resolver for nodes on the Tailscale network,
 // associating them with domain names of the form <mynode>.<mydomain>.<root>.
 // If it is asked to resolve a domain that is not of that form,
@@ -208,6 +138,7 @@ func (r *Resolver) SetConfig(cfg Config) error {
 		r.saveConfigForTests(cfg)
 	}
 
+	routes := make([]route, 0, len(cfg.Routes))
 	reverse := make(map[netaddr.IP]dnsname.FQDN, len(cfg.Hosts))
 
 	for host, ips := range cfg.Hosts {
@@ -216,7 +147,18 @@ func (r *Resolver) SetConfig(cfg Config) error {
 		}
 	}
 
-	r.forwarder.setRoutes(cfg.Routes)
+	for suffix, ips := range cfg.Routes {
+		routes = append(routes, route{
+			Suffix:    suffix,
+			Resolvers: ips,
+		})
+	}
+	// Sort from longest prefix to shortest.
+	sort.Slice(routes, func(i, j int) bool {
+		return routes[i].Suffix.NumLabels() > routes[j].Suffix.NumLabels()
+	})
+
+	r.forwarder.setRoutes(routes)
 
 	r.mu.Lock()
 	defer r.mu.Unlock()

net/dns/resolver/tsdns_test.go

@@ -931,11 +931,8 @@ func TestAllocs(t *testing.T) {
 		query []byte
 		want  int
 	}{
-		// Name lowercasing, response slice created by dns.NewBuilder,
-		// and closure allocation from go call.
-		// (Closure allocation only happens when using new register ABI,
-		// which is amd64 with Go 1.17, and probably more platforms later.)
-		{"forward", dnspacket("test1.ipn.dev.", dns.TypeA, noEdns), 3},
+		// Name lowercasing and response slice created by dns.NewBuilder.
+		{"forward", dnspacket("test1.ipn.dev.", dns.TypeA, noEdns), 2},
 		// 3 extra allocs in rdnsNameToIPv4 and one in marshalPTRRecord (dns.NewName).
 		{"reverse", dnspacket("4.3.2.1.in-addr.arpa.", dns.TypePTR, noEdns), 5},
 	}

net/dnscache/dnscache.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// TODO(bradfitz): update this code to use netaddr more
-
 // Package dnscache contains a minimal DNS cache that makes a bunch of
 // assumptions that are only valid for us. Not recommended for general use.
 package dnscache
@@ -80,9 +78,8 @@ type Resolver struct {
 }
 
 type ipCacheEntry struct {
-	ip      net.IP       // either v4 or v6
-	ip6     net.IP       // nil if no v4 or no v6
-	allIPs  []net.IPAddr // 1+ v4 and/or v6
+	ip      net.IP // either v4 or v6
+	ip6     net.IP // nil if no v4 or no v6
 	expires time.Time
 }
 
@@ -108,82 +105,81 @@ var debug, _ = strconv.ParseBool(os.Getenv("TS_DEBUG_DNS_CACHE"))
 //
 // If err is nil, ip will be non-nil. The v6 address may be nil even
 // with a nil error.
-func (r *Resolver) LookupIP(ctx context.Context, host string) (ip, v6 net.IP, allIPs []net.IPAddr, err error) {
+func (r *Resolver) LookupIP(ctx context.Context, host string) (ip, v6 net.IP, err error) {
 	if ip := net.ParseIP(host); ip != nil {
 		if ip4 := ip.To4(); ip4 != nil {
-			return ip4, nil, []net.IPAddr{{IP: ip4}}, nil
+			return ip4, nil, nil
 		}
 		if debug {
 			log.Printf("dnscache: %q is an IP", host)
 		}
-		return ip, nil, []net.IPAddr{{IP: ip}}, nil
+		return ip, nil, nil
 	}
 
-	if ip, ip6, allIPs, ok := r.lookupIPCache(host); ok {
+	if ip, ip6, ok := r.lookupIPCache(host); ok {
 		if debug {
 			log.Printf("dnscache: %q = %v (cached)", host, ip)
 		}
-		return ip, ip6, allIPs, nil
+		return ip, ip6, nil
 	}
 
-	type ipRes struct {
+	type ipPair struct {
 		ip, ip6 net.IP
-		allIPs  []net.IPAddr
 	}
 	ch := r.sf.DoChan(host, func() (interface{}, error) {
-		ip, ip6, allIPs, err := r.lookupIP(host)
+		ip, ip6, err := r.lookupIP(host)
 		if err != nil {
 			return nil, err
 		}
-		return ipRes{ip, ip6, allIPs}, nil
+		return ipPair{ip, ip6}, nil
 	})
 	select {
 	case res := <-ch:
 		if res.Err != nil {
 			if r.UseLastGood {
-				if ip, ip6, allIPs, ok := r.lookupIPCacheExpired(host); ok {
+				if ip, ip6, ok := r.lookupIPCacheExpired(host); ok {
 					if debug {
 						log.Printf("dnscache: %q using %v after error", host, ip)
 					}
-					return ip, ip6, allIPs, nil
+					return ip, ip6, nil
 				}
 			}
 			if debug {
 				log.Printf("dnscache: error resolving %q: %v", host, res.Err)
 			}
-			return nil, nil, nil, res.Err
+			return nil, nil, res.Err
 		}
-		r := res.Val.(ipRes)
-		return r.ip, r.ip6, r.allIPs, nil
+		pair := res.Val.(ipPair)
+		return pair.ip, pair.ip6, nil
 	case <-ctx.Done():
 		if debug {
 			log.Printf("dnscache: context done while resolving %q: %v", host, ctx.Err())
 		}
-		return nil, nil, nil, ctx.Err()
+		return nil, nil, ctx.Err()
 	}
 }
 
-func (r *Resolver) lookupIPCache(host string) (ip, ip6 net.IP, allIPs []net.IPAddr, ok bool) {
+func (r *Resolver) lookupIPCache(host string) (ip, ip6 net.IP, ok bool) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	if ent, ok := r.ipCache[host]; ok && ent.expires.After(time.Now()) {
-		return ent.ip, ent.ip6, ent.allIPs, true
+		return ent.ip, ent.ip6, true
 	}
-	return nil, nil, nil, false
+	return nil, nil, false
 }
 
-func (r *Resolver) lookupIPCacheExpired(host string) (ip, ip6 net.IP, allIPs []net.IPAddr, ok bool) {
+func (r *Resolver) lookupIPCacheExpired(host string) (ip, ip6 net.IP, ok bool) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	if ent, ok := r.ipCache[host]; ok {
-		return ent.ip, ent.ip6, ent.allIPs, true
+		return ent.ip, ent.ip6, true
 	}
-	return nil, nil, nil, false
+	return nil, nil, false
 }
 
 func (r *Resolver) lookupTimeoutForHost(host string) time.Duration {
 	if r.UseLastGood {
-		if _, _, _, ok := r.lookupIPCacheExpired(host); ok {
+		if _, _, ok := r.lookupIPCacheExpired(host); ok {
 			// If we have some previous good value for this host,
 			// don't give this DNS lookup much time. If we're in a
 			// situation where the user's DNS server is unreachable
@@ -198,12 +194,12 @@ func (r *Resolver) lookupTimeoutForHost(host string) time.Duration {
 	return 10 * time.Second
 }
 
-func (r *Resolver) lookupIP(host string) (ip, ip6 net.IP, allIPs []net.IPAddr, err error) {
-	if ip, ip6, allIPs, ok := r.lookupIPCache(host); ok {
+func (r *Resolver) lookupIP(host string) (ip, ip6 net.IP, err error) {
+	if ip, ip6, ok := r.lookupIPCache(host); ok {
 		if debug {
 			log.Printf("dnscache: %q found in cache as %v", host, ip)
 		}
-		return ip, ip6, allIPs, nil
+		return ip, ip6, nil
 	}
 
 	ctx, cancel := context.WithTimeout(context.Background(), r.lookupTimeoutForHost(host))
@@ -222,10 +218,10 @@ func (r *Resolver) lookupIP(host string) (ip, ip6 net.IP, allIPs []net.IPAddr, e
 		}
 	}
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, err
 	}
 	if len(ips) == 0 {
-		return nil, nil, nil, fmt.Errorf("no IPs for %q found", host)
+		return nil, nil, fmt.Errorf("no IPs for %q found", host)
 	}
 
 	have4 := false
@@ -244,12 +240,12 @@ func (r *Resolver) lookupIP(host string) (ip, ip6 net.IP, allIPs []net.IPAddr, e
 			}
 		}
 	}
-	r.addIPCache(host, ip, ip6, ips, r.ttl())
-	return ip, ip6, ips, nil
+	r.addIPCache(host, ip, ip6, r.ttl())
+	return ip, ip6, nil
 }
 
-func (r *Resolver) addIPCache(host string, ip, ip6 net.IP, allIPs []net.IPAddr, d time.Duration) {
-	if naIP, _ := netaddr.FromStdIP(ip); naIP.IsPrivate() {
+func (r *Resolver) addIPCache(host string, ip, ip6 net.IP, d time.Duration) {
+	if isPrivateIP(ip) {
 		// Don't cache obviously wrong entries from captive portals.
 		// TODO: use DoH or DoT for the forwarding resolver?
 		if debug {
@@ -267,14 +263,27 @@ func (r *Resolver) addIPCache(host string, ip, ip6 net.IP, allIPs []net.IPAddr,
 	if r.ipCache == nil {
 		r.ipCache = make(map[string]ipCacheEntry)
 	}
-	r.ipCache[host] = ipCacheEntry{
-		ip:      ip,
-		ip6:     ip6,
-		allIPs:  allIPs,
-		expires: time.Now().Add(d),
-	}
+	r.ipCache[host] = ipCacheEntry{ip: ip, ip6: ip6, expires: time.Now().Add(d)}
 }
 
+func mustCIDR(s string) *net.IPNet {
+	_, ipNet, err := net.ParseCIDR(s)
+	if err != nil {
+		panic(err)
+	}
+	return ipNet
+}
+
+func isPrivateIP(ip net.IP) bool {
+	return private1.Contains(ip) || private2.Contains(ip) || private3.Contains(ip)
+}
+
+var (
+	private1 = mustCIDR("10.0.0.0/8")
+	private2 = mustCIDR("172.16.0.0/12")
+	private3 = mustCIDR("192.168.0.0/16")
+)
+
 type DialContextFunc func(ctx context.Context, network, address string) (net.Conn, error)
 
 // Dialer returns a wrapped DialContext func that uses the provided dnsCache.
@@ -296,129 +305,39 @@ func Dialer(fwd DialContextFunc, dnsCache *Resolver) DialContextFunc {
 				// Return with original error
 				return
 			}
-			if c, err := raceDial(ctx, fwd, network, ips, port); err == nil {
-				retConn = c
-				ret = nil
-				return
-			}
-		}()
-
-		ip, ip6, allIPs, err := dnsCache.LookupIP(ctx, host)
-		if err != nil {
-			return nil, fmt.Errorf("failed to resolve %q: %w", host, err)
-		}
-		i4s := v4addrs(allIPs)
-		if len(i4s) < 2 {
-			dst := net.JoinHostPort(ip.String(), port)
-			if debug {
-				log.Printf("dnscache: dialing %s, %s for %s", network, dst, address)
-			}
-			c, err := fwd(ctx, network, dst)
-			if err == nil || ctx.Err() != nil || ip6 == nil {
-				return c, err
-			}
-			// Fall back to trying IPv6.
-			dst = net.JoinHostPort(ip6.String(), port)
-			return fwd(ctx, network, dst)
-		}
-
-		// Multiple IPv4 candidates, and 0+ IPv6.
-		ipsToTry := append(i4s, v6addrs(allIPs)...)
-		return raceDial(ctx, fwd, network, ipsToTry, port)
-	}
-}
-
-// fallbackDelay is how long to wait between trying subsequent
-// addresses when multiple options are available.
-// 300ms is the same as Go's Happy Eyeballs fallbackDelay value.
-const fallbackDelay = 300 * time.Millisecond
-
-// raceDial tries to dial port on each ip in ips, starting a new race
-// dial every fallbackDelay apart, returning whichever completes first.
-func raceDial(ctx context.Context, fwd DialContextFunc, network string, ips []netaddr.IP, port string) (net.Conn, error) {
-	ctx, cancel := context.WithCancel(ctx)
-	defer cancel()
-
-	type res struct {
-		c   net.Conn
-		err error
-	}
-	resc := make(chan res)           // must be unbuffered
-	failBoost := make(chan struct{}) // best effort send on dial failure
-
-	go func() {
-		for i, ip := range ips {
-			if i != 0 {
-				timer := time.NewTimer(fallbackDelay)
-				select {
-				case <-timer.C:
-				case <-failBoost:
-					timer.Stop()
-				case <-ctx.Done():
-					timer.Stop()
+			for _, ip := range ips {
+				dst := net.JoinHostPort(ip.String(), port)
+				if c, err := fwd(ctx, network, dst); err == nil {
+					retConn = c
+					ret = nil
 					return
 				}
 			}
-			go func(ip netaddr.IP) {
-				c, err := fwd(ctx, network, net.JoinHostPort(ip.String(), port))
-				if err != nil {
-					// Best effort wake-up a pending dial.
-					// e.g. IPv4 dials failing quickly on an IPv6-only system.
-					// In that case we don't want to wait 300ms per IPv4 before
-					// we get to the IPv6 addresses.
-					select {
-					case failBoost <- struct{}{}:
-					default:
-					}
-				}
-				select {
-				case resc <- res{c, err}:
-				case <-ctx.Done():
-					if c != nil {
-						c.Close()
-					}
-				}
-			}(ip)
-		}
-	}()
+		}()
 
-	var firstErr error
-	var fails int
-	for {
-		select {
-		case r := <-resc:
-			if r.c != nil {
-				return r.c, nil
-			}
-			fails++
-			if firstErr == nil {
-				firstErr = r.err
-			}
-			if fails == len(ips) {
-				return nil, firstErr
-			}
-		case <-ctx.Done():
-			return nil, ctx.Err()
+		ip, ip6, err := dnsCache.LookupIP(ctx, host)
+		if err != nil {
+			return nil, fmt.Errorf("failed to resolve %q: %w", host, err)
 		}
-	}
-}
-
-func v4addrs(aa []net.IPAddr) (ret []netaddr.IP) {
-	for _, a := range aa {
-		if ip, ok := netaddr.FromStdIP(a.IP); ok && ip.Is4() {
-			ret = append(ret, ip)
+		dst := net.JoinHostPort(ip.String(), port)
+		if debug {
+			log.Printf("dnscache: dialing %s, %s for %s", network, dst, address)
 		}
-	}
-	return ret
-}
-
-func v6addrs(aa []net.IPAddr) (ret []netaddr.IP) {
-	for _, a := range aa {
-		if ip, ok := netaddr.FromStdIP(a.IP); ok && ip.Is6() {
-			ret = append(ret, ip)
+		c, err := fwd(ctx, network, dst)
+		if err == nil || ctx.Err() != nil || ip6 == nil {
+			return c, err
 		}
+		// Fall back to trying IPv6.
+		// TODO(bradfitz): this is a primarily for IPv6-only
+		// hosts; it's not supposed to be a real Happy
+		// Eyeballs implementation. We should use the net
+		// package's implementation of that by plumbing this
+		// dnscache impl into net.Dialer.Resolver.Dial and
+		// unmarshal/marshal DNS queries/responses to the net
+		// package. This works for v6-only hosts for now.
+		dst = net.JoinHostPort(ip6.String(), port)
+		return fwd(ctx, network, dst)
 	}
-	return ret
 }
 
 var errTLSHandshakeTimeout = errors.New("timeout doing TLS handshake")

net/dnscache/dnscache_test.go

@@ -5,29 +5,24 @@
 package dnscache
 
 import (
-	"context"
-	"flag"
 	"net"
 	"testing"
-	"time"
 )
 
-var dialTest = flag.String("dial-test", "", "if non-empty, addr:port to test dial")
+func TestIsPrivateIP(t *testing.T) {
+	tests := []struct {
+		ip   string
+		want bool
+	}{
+		{"10.1.2.3", true},
+		{"172.16.1.100", true},
+		{"192.168.1.1", true},
+		{"1.2.3.4", false},
+	}
 
-func TestDialer(t *testing.T) {
-	if *dialTest == "" {
-		t.Skip("skipping; --dial-test is blank")
+	for _, test := range tests {
+		if got := isPrivateIP(net.ParseIP(test.ip)); got != test.want {
+			t.Errorf("isPrivateIP(%q)=%v, want %v", test.ip, got, test.want)
+		}
 	}
-	r := new(Resolver)
-	var std net.Dialer
-	dialer := Dialer(std.DialContext, r)
-	t0 := time.Now()
-	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
-	defer cancel()
-	c, err := dialer(ctx, "tcp", *dialTest)
-	if err != nil {
-		t.Fatal(err)
-	}
-	t.Logf("dialed in %v", time.Since(t0))
-	c.Close()
 }

net/dnsfallback/dns-fallback-servers.json

@@ -90,25 +90,18 @@
 			"RegionName": "r4",
 			"Nodes": [
 				{
-					"Name": "4c",
+					"Name": "4a",
 					"RegionID": 4,
-					"HostName": "derp4c.tailscale.com",
-					"IPv4": "134.122.77.138",
-					"IPv6": "2a03:b0c0:3:d0::1501:6001"
+					"HostName": "derp4.tailscale.com",
+					"IPv4": "167.172.182.26",
+					"IPv6": "2a03:b0c0:3:e0::36e:9001"
 				},
 				{
-					"Name": "4d",
+					"Name": "4b",
 					"RegionID": 4,
-					"HostName": "derp4d.tailscale.com",
-					"IPv4": "134.122.94.167",
-					"IPv6": "2a03:b0c0:3:d0::1501:b001"
-				},
-				{
-					"Name": "4e",
-					"RegionID": 4,
-					"HostName": "derp4e.tailscale.com",
-					"IPv4": "134.122.74.153",
-					"IPv6": "2a03:b0c0:3:d0::29:9001"
+					"HostName": "derp4b.tailscale.com",
+					"IPv4": "157.230.25.0",
+					"IPv6": "2a03:b0c0:3:e0::58f:3001"
 				}
 			]
 		},
@@ -160,25 +153,11 @@
 			"RegionName": "r8",
 			"Nodes": [
 				{
-					"Name": "8b",
+					"Name": "8a",
 					"RegionID": 8,
-					"HostName": "derp8b.tailscale.com",
-					"IPv4": "46.101.74.201",
-					"IPv6": "2a03:b0c0:1:d0::ec1:e001"
-				},
-				{
-					"Name": "8c",
-					"RegionID": 8,
-					"HostName": "derp8c.tailscale.com",
-					"IPv4": "206.189.16.32",
-					"IPv6": "2a03:b0c0:1:d0::e1f:4001"
-				},
-				{
-					"Name": "8d",
-					"RegionID": 8,
-					"HostName": "derp8d.tailscale.com",
-					"IPv4": "178.62.44.132",
-					"IPv6": "2a03:b0c0:1:d0::e08:e001"
+					"HostName": "derp8.tailscale.com",
+					"IPv4": "167.71.139.179",
+					"IPv6": "2a03:b0c0:1:e0::3cc:e001"
 				}
 			]
 		},

net/interfaces/interfaces.go

@@ -134,7 +134,7 @@ func LocalAddresses() (regular, loopback []netaddr.IP, err error) {
 					// but their OS supports IPv6 so they have an fe80::
 					// address. We don't want to report all of those
 					// IPv6 LL to Control.
-				} else if ip.Is6() && ip.IsPrivate() {
+				} else if ip.Is6() && tsaddr.IsULA(ip) {
 					// Google Cloud Run uses NAT with IPv6 Unique
 					// Local Addresses to provide IPv6 connectivity.
 					ula6 = append(ula6, ip)
@@ -479,7 +479,7 @@ func HTTPOfListener(ln net.Listener) string {
 	var privateIP string
 	ForeachInterfaceAddress(func(i Interface, pfx netaddr.IPPrefix) {
 		ip := pfx.IP()
-		if ip.IsPrivate() {
+		if isPrivateIP(ip) {
 			if privateIP == "" {
 				privateIP = ip.String()
 			}
@@ -519,15 +519,21 @@ func LikelyHomeRouterIP() (gateway, myIP netaddr.IP, ok bool) {
 		if !i.IsUp() || ip.IsZero() || !myIP.IsZero() {
 			return
 		}
-		if gateway.IsPrivate() && ip.IsPrivate() {
-			myIP = ip
-			ok = true
-			return
+		for _, prefix := range privatev4s {
+			if prefix.Contains(gateway) && prefix.Contains(ip) {
+				myIP = ip
+				ok = true
+				return
+			}
 		}
 	})
 	return gateway, myIP, !myIP.IsZero()
 }
 
+func isPrivateIP(ip netaddr.IP) bool {
+	return private1.Contains(ip) || private2.Contains(ip) || private3.Contains(ip)
+}
+
 // isUsableV4 reports whether ip is a usable IPv4 address which could
 // conceivably be used to get Internet connectivity. Globally routable and
 // private IPv4 addresses are always Usable, and link local 169.254.x.x
@@ -548,11 +554,23 @@ func isUsableV4(ip netaddr.IP) bool {
 // (fc00::/7) are in some environments used with address translation.
 func isUsableV6(ip netaddr.IP) bool {
 	return v6Global1.Contains(ip) ||
-		(ip.Is6() && ip.IsPrivate() && !tsaddr.TailscaleULARange().Contains(ip))
+		(tsaddr.IsULA(ip) && !tsaddr.TailscaleULARange().Contains(ip))
+}
+
+func mustCIDR(s string) netaddr.IPPrefix {
+	prefix, err := netaddr.ParseIPPrefix(s)
+	if err != nil {
+		panic(err)
+	}
+	return prefix
 }
 
 var (
-	v6Global1 = netaddr.MustParseIPPrefix("2000::/3")
+	private1   = mustCIDR("10.0.0.0/8")
+	private2   = mustCIDR("172.16.0.0/12")
+	private3   = mustCIDR("192.168.0.0/16")
+	privatev4s = []netaddr.IPPrefix{private1, private2, private3}
+	v6Global1  = mustCIDR("2000::/3")
 )
 
 // anyInterestingIP reports whether pfxs contains any IP that matches

net/interfaces/interfaces_darwin_test.go

@@ -73,7 +73,7 @@ func likelyHomeRouterIPDarwinExec() (ret netaddr.IP, ok bool) {
 			return nil
 		}
 		ip, err := netaddr.ParseIP(string(mem.Append(nil, ipm)))
-		if err == nil && ip.IsPrivate() {
+		if err == nil && isPrivateIP(ip) {
 			ret = ip
 			// We've found what we're looking for.
 			return errStopReadingNetstatTable

net/interfaces/interfaces_linux.go

@@ -72,7 +72,7 @@ func likelyHomeRouterIPLinux() (ret netaddr.IP, ok bool) {
 			return nil // ignore error, skip line and keep going
 		}
 		ip := netaddr.IPv4(byte(ipu32), byte(ipu32>>8), byte(ipu32>>16), byte(ipu32>>24))
-		if ip.IsPrivate() {
+		if isPrivateIP(ip) {
 			ret = ip
 		}
 		return nil

net/interfaces/interfaces_linux_test.go

@@ -73,32 +73,6 @@ func TestExtremelyLongProcNetRoute(t *testing.T) {
 	}
 }
 
-// test the specific /proc/net/route path as found on AWS App Runner instances
-func TestAwsAppRunnerDefaultRouteInterface(t *testing.T) {
-	dir := t.TempDir()
-	savedProcNetRoutePath := procNetRoutePath
-	defer func() { procNetRoutePath = savedProcNetRoutePath }()
-	procNetRoutePath = filepath.Join(dir, "CloudRun")
-	buf := []byte("Iface\tDestination\tGateway\tFlags\tRefCnt\tUse\tMetric\tMask\tMTU\tWindow\tIRTT\n" +
-		"eth0\t00000000\tF9AFFEA9\t0003\t0\t0\t0\t00000000\t0\t0\t0\n" +
-		"*\tFEA9FEA9\t00000000\t0005\t0\t0\t0\tFFFFFFFF\t0\t0\t0\n" +
-		"ecs-eth0\t02AAFEA9\t01ACFEA9\t0007\t0\t0\t0\tFFFFFFFF\t0\t0\t0\n" +
-		"ecs-eth0\t00ACFEA9\t00000000\t0001\t0\t0\t0\t00FFFFFF\t0\t0\t0\n" +
-		"eth0\t00AFFEA9\t00000000\t0001\t0\t0\t0\t00FFFFFF\t0\t0\t0\n")
-	err := ioutil.WriteFile(procNetRoutePath, buf, 0644)
-	if err != nil {
-		t.Fatal(err)
-	}
-	got, err := DefaultRouteInterface()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if got != "eth0" {
-		t.Fatalf("got %s, want eth0", got)
-	}
-}
-
 func BenchmarkDefaultRouteInterface(b *testing.B) {
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {

net/interfaces/interfaces_test.go

@@ -58,8 +58,6 @@ func TestIsUsableV6(t *testing.T) {
 		{"zeros", "0000:0000:0000:0000:0000:0000:0000:0000", false},
 		{"Link Local", "fe80::1", false},
 		{"Global", "2602::1", true},
-		{"IPv4 public", "192.0.2.1", false},
-		{"IPv4 private", "192.168.1.1", false},
 	}
 
 	for _, test := range tests {

net/interfaces/interfaces_windows.go

@@ -93,7 +93,7 @@ func likelyHomeRouterIPWindows() (ret netaddr.IP, ok bool) {
 		}
 	}
 
-	if !ret.IsZero() && !ret.IsPrivate() {
+	if !ret.IsZero() && !isPrivateIP(ret) {
 		// Default route has a non-private gateway
 		return netaddr.IP{}, false
 	}

net/netns/netns.go

@@ -17,8 +17,6 @@ package netns
 import (
 	"context"
 	"net"
-
-	"inet.af/netaddr"
 )
 
 // Listener returns a new net.Listener with its Control hook func
@@ -68,19 +66,3 @@ type Dialer interface {
 	Dial(network, address string) (net.Conn, error)
 	DialContext(ctx context.Context, network, address string) (net.Conn, error)
 }
-
-func isLocalhost(addr string) bool {
-	host, _, err := net.SplitHostPort(addr)
-	if err != nil {
-		// error means the string didn't contain a port number, so use the string directly
-		host = addr
-	}
-
-	// localhost6 == RedHat /etc/hosts for ::1, ip6-loopback & ip6-localhost == Debian /etc/hosts for ::1
-	if host == "localhost" || host == "localhost6" || host == "ip6-loopback" || host == "ip6-localhost" {
-		return true
-	}
-
-	ip, _ := netaddr.ParseIP(host)
-	return ip.IsLoopback()
-}

net/netns/netns_linux.go

@@ -7,8 +7,8 @@
 package netns
 
 import (
+	"flag"
 	"fmt"
-	"net"
 	"os"
 	"os/exec"
 	"sync"
@@ -26,54 +26,32 @@ import (
 // wgengine/router/router_linux.go.
 const tailscaleBypassMark = 0x80000
 
-// socketMarkWorksOnce is the sync.Once & cached value for useSocketMark.
-var socketMarkWorksOnce struct {
+// ipRuleOnce is the sync.Once & cached value for ipRuleAvailable.
+var ipRuleOnce struct {
 	sync.Once
 	v bool
 }
 
-// socketMarkWorks returns whether SO_MARK works.
-func socketMarkWorks() bool {
-	addr, err := net.ResolveUDPAddr("udp", "127.0.0.1:1")
-	if err != nil {
-		return true // unsure, returning true does the least harm.
-	}
-
-	sConn, err := net.DialUDP("udp", nil, addr)
-	if err != nil {
-		return true // unsure, return true
-	}
-	defer sConn.Close()
-
-	rConn, err := sConn.SyscallConn()
-	if err != nil {
-		return true // unsure, return true
-	}
-
-	var sockErr error
-	err = rConn.Control(func(fd uintptr) {
-		sockErr = setBypassMark(fd)
-	})
-	if err != nil || sockErr != nil {
-		return false
-	}
-
-	return true
-}
-
-// useSocketMark reports whether SO_MARK works.
+// ipRuleAvailable reports whether the 'ip rule' command works.
 // If it doesn't, we have to use SO_BINDTODEVICE on our sockets instead.
-func useSocketMark() bool {
-	socketMarkWorksOnce.Do(func() {
-		ipRuleWorks := exec.Command("ip", "rule").Run() == nil
-		socketMarkWorksOnce.v = ipRuleWorks && socketMarkWorks()
+func ipRuleAvailable() bool {
+	ipRuleOnce.Do(func() {
+		ipRuleOnce.v = exec.Command("ip", "rule").Run() == nil
 	})
-	return socketMarkWorksOnce.v
+	return ipRuleOnce.v
 }
 
 // ignoreErrors returns true if we should ignore setsocketopt errors in
 // this instance.
 func ignoreErrors() bool {
+	// If we're in a test, ignore errors. Assume the test knows
+	// what it's doing and will do its own skips or permission
+	// checks if it's setting up a world that needs netns to work.
+	// But by default, assume that tests don't need netns and it's
+	// harmless to ignore the sockopts failing.
+	if flag.CommandLine.Lookup("test.v") != nil {
+		return true
+	}
 	if os.Getuid() != 0 {
 		// only root can manipulate these socket flags
 		return true
@@ -86,14 +64,9 @@ func ignoreErrors() bool {
 // It's intentionally the same signature as net.Dialer.Control
 // and net.ListenConfig.Control.
 func control(network, address string, c syscall.RawConn) error {
-	if isLocalhost(address) {
-		// Don't bind to an interface for localhost connections.
-		return nil
-	}
-
 	var sockErr error
 	err := c.Control(func(fd uintptr) {
-		if useSocketMark() {
+		if ipRuleAvailable() {
 			sockErr = setBypassMark(fd)
 		} else {
 			sockErr = bindToDevice(fd)

net/netns/netns_linux_test.go

@@ -49,9 +49,3 @@ func TestBypassMarkInSync(t *testing.T) {
 	}
 	t.Errorf("tailscaleBypassMark not found in router_linux.go")
 }
-
-func TestSocketMarkWorks(t *testing.T) {
-	_ = socketMarkWorks()
-	// we cannot actually assert whether the test runner has SO_MARK available
-	// or not, as we don't know. We're just checking that it doesn't panic.
-}

net/netns/netns_test.go

@@ -40,40 +40,3 @@ func TestDial(t *testing.T) {
 	defer c.Close()
 	t.Logf("got addr %v", c.RemoteAddr())
 }
-
-func TestIsLocalhost(t *testing.T) {
-	tests := []struct {
-		name string
-		host string
-		want bool
-	}{
-		{"IPv4 loopback", "127.0.0.1", true},
-		{"IPv4 !loopback", "192.168.0.1", false},
-		{"IPv4 loopback with port", "127.0.0.1:1", true},
-		{"IPv4 !loopback with port", "192.168.0.1:1", false},
-		{"IPv4 unspecified", "0.0.0.0", false},
-		{"IPv4 unspecified with port", "0.0.0.0:1", false},
-		{"IPv6 loopback", "::1", true},
-		{"IPv6 !loopback", "2001:4860:4860::8888", false},
-		{"IPv6 loopback with port", "[::1]:1", true},
-		{"IPv6 !loopback with port", "[2001:4860:4860::8888]:1", false},
-		{"IPv6 unspecified", "::", false},
-		{"IPv6 unspecified with port", "[::]:1", false},
-		{"empty", "", false},
-		{"hostname", "example.com", false},
-		{"localhost", "localhost", true},
-		{"localhost6", "localhost6", true},
-		{"localhost with port", "localhost:1", true},
-		{"localhost6 with port", "localhost6:1", true},
-		{"ip6-localhost", "ip6-localhost", true},
-		{"ip6-localhost with port", "ip6-localhost:1", true},
-		{"ip6-loopback", "ip6-loopback", true},
-		{"ip6-loopback with port", "ip6-loopback:1", true},
-	}
-
-	for _, test := range tests {
-		if got := isLocalhost(test.host); got != test.want {
-			t.Errorf("isLocalhost(%q) = %v, want %v", test.name, got, test.want)
-		}
-	}
-}

net/portmapper/disabled_stubs.go

@@ -1,25 +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 ios
-// (https://github.com/tailscale/tailscale/issues/2495)
-
-package portmapper
-
-import (
-	"context"
-
-	"inet.af/netaddr"
-)
-
-type upnpClient interface{}
-
-func (c *Client) getUPnPPortMapping(
-	ctx context.Context,
-	gw netaddr.IP,
-	internal netaddr.IPPort,
-	prevPort uint16,
-) (external netaddr.IPPort, ok bool) {
-	return netaddr.IPPort{}, false
-}

net/portmapper/portmapper.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package portmapper is a UDP port mapping client. It currently allows for mapping over
-// NAT-PMP and UPnP, but will perhaps do PCP later.
+// 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 (
@@ -14,7 +14,6 @@ import (
 	"fmt"
 	"io"
 	"net"
-	"net/http"
 	"sync"
 	"time"
 
@@ -64,40 +63,18 @@ type Client struct {
 	pmpPubIPTime time.Time  // time pmpPubIP last verified
 	pmpLastEpoch uint32
 
-	pcpSawTime time.Time // time we last saw PCP was available
+	pcpSawTime  time.Time // time we last saw PCP was available
+	uPnPSawTime time.Time // time we last saw UPnP was available
 
-	uPnPSawTime    time.Time         // time we last saw UPnP was available
-	uPnPMeta       uPnPDiscoResponse // Location header from UPnP UDP discovery response
-	uPnPHTTPClient *http.Client      // nil until needed
-
-	localPort uint16
-
-	mapping mapping // non-nil if we have a mapping
-}
-
-// mapping represents a created port-mapping over some protocol.  It specifies a lease duration,
-// how to release the mapping, and whether the map is still valid.
-//
-// After a mapping is created, it should be immutable, and thus reads should be safe across
-// concurrent goroutines.
-type mapping interface {
-	// Release will attempt to unmap the established port mapping. It will block until completion,
-	// but can be called asynchronously. Release should be idempotent, and thus even if called
-	// multiple times should not cause additional side-effects.
-	Release(context.Context)
-	// goodUntil will return the lease time that the mapping is valid for.
-	GoodUntil() time.Time
-	// renewAfter returns the earliest time that the mapping should be renewed.
-	RenewAfter() time.Time
-	// externalIPPort indicates what port the mapping can be reached from on the outside.
-	External() netaddr.IPPort
+	localPort  uint16
+	pmpMapping *pmpMapping // non-nil if we have a PMP mapping
 }
 
 // HaveMapping reports whether we have a current valid mapping.
 func (c *Client) HaveMapping() bool {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	return c.mapping != nil && c.mapping.GoodUntil().After(time.Now())
+	return c.pmpMapping != nil && c.pmpMapping.goodUntil.After(time.Now())
 }
 
 // pmpMapping is an already-created PMP mapping.
@@ -117,13 +94,9 @@ func (m *pmpMapping) externalValid() bool {
 	return !m.external.IP().IsZero() && m.external.Port() != 0
 }
 
-func (p *pmpMapping) GoodUntil() time.Time     { return p.goodUntil }
-func (p *pmpMapping) RenewAfter() time.Time    { return p.renewAfter }
-func (p *pmpMapping) External() netaddr.IPPort { return p.external }
-
-// Release does a best effort fire-and-forget release of the PMP mapping m.
-func (m *pmpMapping) Release(ctx context.Context) {
-	uc, err := netns.Listener().ListenPacket(ctx, "udp4", ":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
 	}
@@ -193,6 +166,7 @@ func (c *Client) gatewayAndSelfIP() (gw, myIP netaddr.IP, ok bool) {
 		gw = netaddr.IP{}
 		myIP = netaddr.IP{}
 	}
+
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
@@ -205,11 +179,11 @@ func (c *Client) gatewayAndSelfIP() (gw, myIP netaddr.IP, ok bool) {
 }
 
 func (c *Client) invalidateMappingsLocked(releaseOld bool) {
-	if c.mapping != nil {
+	if c.pmpMapping != nil {
 		if releaseOld {
-			c.mapping.Release(context.Background())
+			c.pmpMapping.release()
 		}
-		c.mapping = nil
+		c.pmpMapping = nil
 	}
 	c.pmpPubIP = netaddr.IP{}
 	c.pmpPubIPTime = time.Time{}
@@ -275,7 +249,7 @@ func IsNoMappingError(err error) bool {
 
 var (
 	ErrNoPortMappingServices = errors.New("no port mapping services were found")
-	ErrGatewayRange          = errors.New("skipping portmap; gateway range likely lacks support")
+	ErrGatewayNotFound       = errors.New("failed to look up gateway address")
 )
 
 // GetCachedMappingOrStartCreatingOne quickly returns with our current cached portmapping, if any.
@@ -288,12 +262,12 @@ func (c *Client) GetCachedMappingOrStartCreatingOne() (external netaddr.IPPort,
 
 	// Do we have an existing mapping that's valid?
 	now := time.Now()
-	if m := c.mapping; m != nil {
-		if now.Before(m.GoodUntil()) {
-			if now.After(m.RenewAfter()) {
+	if m := c.pmpMapping; m != nil {
+		if now.Before(m.goodUntil) {
+			if now.After(m.renewAfter) {
 				c.maybeStartMappingLocked()
 			}
-			return m.External(), true
+			return m.external, true
 		}
 	}
 
@@ -336,15 +310,14 @@ func (c *Client) createMapping() {
 func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPort, err error) {
 	gw, myIP, ok := c.gatewayAndSelfIP()
 	if !ok {
-		return netaddr.IPPort{}, NoMappingError{ErrGatewayRange}
+		return netaddr.IPPort{}, NoMappingError{ErrGatewayNotFound}
 	}
 
 	c.mu.Lock()
 	localPort := c.localPort
-	internalAddr := netaddr.IPPortFrom(myIP, localPort)
 	m := &pmpMapping{
 		gw:       gw,
-		internal: internalAddr,
+		internal: netaddr.IPPortFrom(myIP, localPort),
 	}
 
 	// prevPort is the port we had most previously, if any. We try
@@ -353,13 +326,13 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
 
 	// Do we have an existing mapping that's valid?
 	now := time.Now()
-	if m := c.mapping; m != nil {
-		if now.Before(m.RenewAfter()) {
+	if m := c.pmpMapping; m != nil {
+		if now.Before(m.renewAfter) {
 			defer c.mu.Unlock()
-			return m.External(), nil
+			return m.external, nil
 		}
 		// The mapping might still be valid, so just try to renew it.
-		prevPort = m.External().Port()
+		prevPort = m.external.Port()
 	}
 
 	// If we just did a Probe (e.g. via netchecker) but didn't
@@ -371,10 +344,6 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
 	}
 	if c.lastProbe.After(now.Add(-5*time.Second)) && !haveRecentPMP {
 		c.mu.Unlock()
-		// fallback to UPnP portmapping
-		if mapping, ok := c.getUPnPPortMapping(ctx, gw, internalAddr, prevPort); ok {
-			return mapping, nil
-		}
 		return netaddr.IPPort{}, NoMappingError{ErrNoPortMappingServices}
 	}
 
@@ -412,10 +381,6 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
 			if ctx.Err() == context.Canceled {
 				return netaddr.IPPort{}, err
 			}
-			// fallback to UPnP portmapping
-			if mapping, ok := c.getUPnPPortMapping(ctx, gw, internalAddr, prevPort); ok {
-				return mapping, nil
-			}
 			return netaddr.IPPort{}, NoMappingError{ErrNoPortMappingServices}
 		}
 		srcu := srci.(*net.UDPAddr)
@@ -448,7 +413,7 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
 		if m.externalValid() {
 			c.mu.Lock()
 			defer c.mu.Unlock()
-			c.mapping = m
+			c.pmpMapping = m
 			return m.external, nil
 		}
 	}
@@ -545,7 +510,7 @@ type ProbeResult struct {
 func (c *Client) Probe(ctx context.Context) (res ProbeResult, err error) {
 	gw, myIP, ok := c.gatewayAndSelfIP()
 	if !ok {
-		return res, ErrGatewayRange
+		return res, ErrGatewayNotFound
 	}
 	defer func() {
 		if err == nil {
@@ -606,15 +571,9 @@ func (c *Client) Probe(ctx context.Context) (res ProbeResult, err error) {
 		switch port {
 		case upnpPort:
 			if mem.Contains(mem.B(buf[:n]), mem.S(":InternetGatewayDevice:")) {
-				meta, err := parseUPnPDiscoResponse(buf[:n])
-				if err != nil {
-					c.logf("unrecognized UPnP discovery response; ignoring")
-				}
-				// log.Printf("UPnP reply %+v, %q", meta, buf[:n])
 				res.UPnP = true
 				c.mu.Lock()
 				c.uPnPSawTime = time.Now()
-				c.uPnPMeta = meta
 				c.mu.Unlock()
 			}
 		case pcpPort: // same as pmpPort
@@ -728,8 +687,6 @@ func parsePCPResponse(b []byte) (res pcpResponse, ok bool) {
 	return res, true
 }
 
-var pmpReqExternalAddrPacket = []byte{0, 0} // version 0, opcode 0 = "Public address request"
-
 const (
 	upnpPort = 1900
 )
@@ -739,3 +696,5 @@ var uPnPPacket = []byte("M-SEARCH * HTTP/1.1\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

@@ -17,7 +17,6 @@ func TestCreateOrGetMapping(t *testing.T) {
 		t.Skip("skipping test without HIT_NETWORK=1")
 	}
 	c := NewClient(t.Logf, nil)
-	defer c.Close()
 	c.SetLocalPort(1234)
 	for i := 0; i < 2; i++ {
 		if i > 0 {
@@ -33,13 +32,12 @@ func TestClientProbe(t *testing.T) {
 		t.Skip("skipping test without HIT_NETWORK=1")
 	}
 	c := NewClient(t.Logf, nil)
-	defer c.Close()
-	for i := 0; i < 3; i++ {
+	for i := 0; i < 2; i++ {
 		if i > 0 {
 			time.Sleep(100 * time.Millisecond)
 		}
 		res, err := c.Probe(context.Background())
-		t.Logf("Got(t=%dms): %+v, %v", i*100, res, err)
+		t.Logf("Got: %+v, %v", res, err)
 	}
 }
 
@@ -48,7 +46,6 @@ func TestClientProbeThenMap(t *testing.T) {
 		t.Skip("skipping test without HIT_NETWORK=1")
 	}
 	c := NewClient(t.Logf, nil)
-	defer c.Close()
 	c.SetLocalPort(1234)
 	res, err := c.Probe(context.Background())
 	t.Logf("Probe: %+v, %v", res, err)

net/portmapper/upnp.go

@@ -1,313 +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 !ios
-// (https://github.com/tailscale/tailscale/issues/2495)
-
-package portmapper
-
-import (
-	"bufio"
-	"bytes"
-	"context"
-	"fmt"
-	"log"
-	"math/rand"
-	"net/http"
-	"net/url"
-	"time"
-
-	"github.com/tailscale/goupnp"
-	"github.com/tailscale/goupnp/dcps/internetgateway2"
-	"inet.af/netaddr"
-	"tailscale.com/control/controlknobs"
-	"tailscale.com/net/netns"
-)
-
-// VerboseLogs controls verbose debug logging.
-// It exists for use by "tailscaled debug --portmap".
-var VerboseLogs bool
-
-// References:
-//
-// WANIP Connection v2: http://upnp.org/specs/gw/UPnP-gw-WANIPConnection-v2-Service.pdf
-
-// upnpMapping is a port mapping over the upnp protocol. After being created it is immutable,
-// but the client field may be shared across mapping instances.
-type upnpMapping struct {
-	gw         netaddr.IP
-	external   netaddr.IPPort
-	internal   netaddr.IPPort
-	goodUntil  time.Time
-	renewAfter time.Time
-
-	// client is a connection to a upnp device, and may be reused across different UPnP mappings.
-	client upnpClient
-}
-
-func (u *upnpMapping) GoodUntil() time.Time     { return u.goodUntil }
-func (u *upnpMapping) RenewAfter() time.Time    { return u.renewAfter }
-func (u *upnpMapping) External() netaddr.IPPort { return u.external }
-func (u *upnpMapping) Release(ctx context.Context) {
-	u.client.DeletePortMapping(ctx, "", u.external.Port(), "udp")
-}
-
-// upnpClient is an interface over the multiple different clients exported by goupnp,
-// exposing the functions we need for portmapping. Those clients are auto-generated from XML-specs,
-// which is why they're not very idiomatic.
-type upnpClient interface {
-	AddPortMapping(
-		ctx context.Context,
-
-		// remoteHost is the remote device sending packets to this device, in the format of x.x.x.x.
-		// The empty string, "", means any host out on the internet can send packets in.
-		remoteHost string,
-
-		// externalPort is the exposed port of this port mapping. Visible during NAT operations.
-		// 0 will let the router select the port, but there is an additional call,
-		// `AddAnyPortMapping`, which is available on 1 of the 3 possible protocols,
-		// which should be used if available. See `addAnyPortMapping` below, which calls this if
-		// `AddAnyPortMapping` is not supported.
-		externalPort uint16,
-
-		// protocol is whether this is over TCP or UDP. Either "tcp" or "udp".
-		protocol string,
-
-		// internalPort is the port that the gateway device forwards the traffic to.
-		internalPort uint16,
-		// internalClient is the IP address that packets will be forwarded to for this mapping.
-		// Internal client is of the form "x.x.x.x".
-		internalClient string,
-
-		// enabled is whether this portmapping should be enabled or disabled.
-		enabled bool,
-		// portMappingDescription is a user-readable description of this portmapping.
-		portMappingDescription string,
-		// leaseDurationSec is the duration of this portmapping. The value of this argument must be
-		// greater than 0. From the spec, it appears if it is set to 0, it will switch to using
-		// 604800 seconds, but not sure why this is desired. The recommended time is 3600 seconds.
-		leaseDurationSec uint32,
-	) error
-
-	DeletePortMapping(ctx context.Context, remoteHost string, externalPort uint16, protocol string) error
-	GetExternalIPAddress(ctx context.Context) (externalIPAddress string, err error)
-}
-
-// tsPortMappingDesc gets sent to UPnP clients as a human-readable label for the portmapping.
-// It is not used for anything other than labelling.
-const tsPortMappingDesc = "tailscale-portmap"
-
-// addAnyPortMapping abstracts over different UPnP client connections, calling the available
-// AddAnyPortMapping call if available for WAN IP connection v2, otherwise defaulting to the old
-// behavior of calling AddPortMapping with port = 0 to specify a wildcard port.
-// It returns the new external port (which may not be identical to the external port specified),
-// or an error.
-//
-// TODO(bradfitz): also returned the actual lease duration obtained. and check it regularly.
-func addAnyPortMapping(
-	ctx context.Context,
-	upnp upnpClient,
-	externalPort uint16,
-	internalPort uint16,
-	internalClient string,
-	leaseDuration time.Duration,
-) (newPort uint16, err error) {
-	if upnp, ok := upnp.(*internetgateway2.WANIPConnection2); ok {
-		return upnp.AddAnyPortMapping(
-			ctx,
-			"",
-			externalPort,
-			"udp",
-			internalPort,
-			internalClient,
-			true,
-			tsPortMappingDesc,
-			uint32(leaseDuration.Seconds()),
-		)
-	}
-	for externalPort == 0 {
-		externalPort = uint16(rand.Intn(65535))
-	}
-	err = upnp.AddPortMapping(
-		ctx,
-		"",
-		externalPort,
-		"udp",
-		internalPort,
-		internalClient,
-		true,
-		tsPortMappingDesc,
-		uint32(leaseDuration.Seconds()),
-	)
-	return externalPort, err
-}
-
-// getUPnPClient gets a client for interfacing with UPnP, ignoring the underlying protocol for
-// now.
-// Adapted from https://github.com/huin/goupnp/blob/master/GUIDE.md.
-//
-// The gw is the detected gateway.
-//
-// The meta is the most recently parsed UDP discovery packet response
-// from the Internet Gateway Device.
-//
-// The provided ctx is not retained in the returned upnpClient, but
-// its associated HTTP client is (if set via goupnp.WithHTTPClient).
-func getUPnPClient(ctx context.Context, gw netaddr.IP, meta uPnPDiscoResponse) (upnpClient, error) {
-	if controlknobs.DisableUPnP() {
-		return nil, nil
-	}
-
-	if meta.Location == "" {
-		return nil, nil
-	}
-
-	if VerboseLogs {
-		log.Printf("fetching %v", meta.Location)
-	}
-	u, err := url.Parse(meta.Location)
-	if err != nil {
-		return nil, err
-	}
-
-	ipp, err := netaddr.ParseIPPort(u.Host)
-	if err != nil {
-		return nil, fmt.Errorf("unexpected host %q in %q", u.Host, meta.Location)
-	}
-	if ipp.IP() != gw {
-		return nil, fmt.Errorf("UPnP discovered root %q does not match gateway IP %v; ignoring UPnP",
-			meta.Location, gw)
-	}
-
-	ctx, cancel := context.WithTimeout(ctx, 500*time.Millisecond)
-	defer cancel()
-
-	// This part does a network fetch.
-	root, err := goupnp.DeviceByURL(ctx, u)
-	if err != nil {
-		return nil, err
-	}
-
-	// These parts don't do a network fetch.
-	// Pick the best service type available.
-	if cc, _ := internetgateway2.NewWANIPConnection2ClientsFromRootDevice(ctx, root, u); len(cc) > 0 {
-		return cc[0], nil
-	}
-	if cc, _ := internetgateway2.NewWANIPConnection1ClientsFromRootDevice(ctx, root, u); len(cc) > 0 {
-		return cc[0], nil
-	}
-	if cc, _ := internetgateway2.NewWANPPPConnection1ClientsFromRootDevice(ctx, root, u); len(cc) > 0 {
-		return cc[0], nil
-	}
-	return nil, nil
-}
-
-func (c *Client) upnpHTTPClientLocked() *http.Client {
-	if c.uPnPHTTPClient == nil {
-		c.uPnPHTTPClient = &http.Client{
-			Transport: &http.Transport{
-				DialContext:     netns.NewDialer().DialContext,
-				IdleConnTimeout: 2 * time.Second, // LAN is cheap
-			},
-		}
-	}
-	return c.uPnPHTTPClient
-}
-
-// getUPnPPortMapping attempts to create a port-mapping over the UPnP protocol. On success,
-// it will return the externally exposed IP and port. Otherwise, it will return a zeroed IP and
-// port and an error.
-func (c *Client) getUPnPPortMapping(
-	ctx context.Context,
-	gw netaddr.IP,
-	internal netaddr.IPPort,
-	prevPort uint16,
-) (external netaddr.IPPort, ok bool) {
-	if controlknobs.DisableUPnP() {
-		return netaddr.IPPort{}, false
-	}
-	now := time.Now()
-	upnp := &upnpMapping{
-		gw:       gw,
-		internal: internal,
-	}
-
-	var client upnpClient
-	var err error
-	c.mu.Lock()
-	oldMapping, ok := c.mapping.(*upnpMapping)
-	meta := c.uPnPMeta
-	httpClient := c.upnpHTTPClientLocked()
-	c.mu.Unlock()
-	if ok && oldMapping != nil {
-		client = oldMapping.client
-	} else {
-		ctx := goupnp.WithHTTPClient(ctx, httpClient)
-		client, err = getUPnPClient(ctx, gw, meta)
-		if VerboseLogs {
-			log.Printf("getUPnPClient: %T, %v", client, err)
-		}
-		if err != nil {
-			return netaddr.IPPort{}, false
-		}
-	}
-	if client == nil {
-		return netaddr.IPPort{}, false
-	}
-
-	var newPort uint16
-	newPort, err = addAnyPortMapping(
-		ctx,
-		client,
-		prevPort,
-		internal.Port(),
-		internal.IP().String(),
-		time.Second*pmpMapLifetimeSec,
-	)
-	if VerboseLogs {
-		log.Printf("addAnyPortMapping: %v, %v", newPort, err)
-	}
-	if err != nil {
-		return netaddr.IPPort{}, false
-	}
-	// TODO cache this ip somewhere?
-	extIP, err := client.GetExternalIPAddress(ctx)
-	if VerboseLogs {
-		log.Printf("client.GetExternalIPAddress: %v, %v", extIP, err)
-	}
-	if err != nil {
-		// TODO this doesn't seem right
-		return netaddr.IPPort{}, false
-	}
-	externalIP, err := netaddr.ParseIP(extIP)
-	if err != nil {
-		return netaddr.IPPort{}, false
-	}
-
-	upnp.external = netaddr.IPPortFrom(externalIP, newPort)
-	d := time.Duration(pmpMapLifetimeSec) * time.Second
-	upnp.goodUntil = now.Add(d)
-	upnp.renewAfter = now.Add(d / 2)
-	upnp.client = client
-	c.mu.Lock()
-	defer c.mu.Unlock()
-	c.mapping = upnp
-	c.localPort = newPort
-	return upnp.external, true
-}
-
-type uPnPDiscoResponse struct {
-	Location string
-}
-
-// parseUPnPDiscoResponse parses a UPnP HTTP-over-UDP discovery response.
-func parseUPnPDiscoResponse(body []byte) (uPnPDiscoResponse, error) {
-	var r uPnPDiscoResponse
-	res, err := http.ReadResponse(bufio.NewReaderSize(bytes.NewReader(body), 128), nil)
-	if err != nil {
-		return r, err
-	}
-	r.Location = res.Header.Get("Location")
-	return r, nil
-}

net/portmapper/upnp_test.go

@@ -1,95 +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 portmapper
-
-import (
-	"context"
-	"fmt"
-	"io"
-	"net"
-	"net/http"
-	"net/http/httptest"
-	"reflect"
-	"testing"
-
-	"inet.af/netaddr"
-)
-
-// Google Wifi
-const (
-	googleWifiUPnPDisco = "HTTP/1.1 200 OK\r\nCACHE-CONTROL: max-age=120\r\nST: urn:schemas-upnp-org:device:InternetGatewayDevice:2\r\nUSN: uuid:a9708184-a6c0-413a-bbac-11bcf7e30ece::urn:schemas-upnp-org:device:InternetGatewayDevice:2\r\nEXT:\r\nSERVER: Linux/5.4.0-1034-gcp UPnP/1.1 MiniUPnPd/1.9\r\nLOCATION: http://192.168.86.1:5000/rootDesc.xml\r\nOPT: \"http://schemas.upnp.org/upnp/1/0/\"; ns=01\r\n01-NLS: 1\r\nBOOTID.UPNP.ORG: 1\r\nCONFIGID.UPNP.ORG: 1337\r\n\r\n"
-
-	googleWifiRootDescXML = `<?xml version="1.0"?>
-<root xmlns="urn:schemas-upnp-org:device-1-0"><specVersion><major>1</major><minor>0</minor></specVersion><device><deviceType>urn:schemas-upnp-org:device:InternetGatewayDevice:2</deviceType><friendlyName>OnHub</friendlyName><manufacturer>Google</manufacturer><manufacturerURL>http://google.com/</manufacturerURL><modelDescription>Wireless Router</modelDescription><modelName>OnHub</modelName><modelNumber>1</modelNumber><modelURL>https://on.google.com/hub/</modelURL><serialNumber>00000000</serialNumber><UDN>uuid:a9708184-a6c0-413a-bbac-11bcf7e30ece</UDN><serviceList><service><serviceType>urn:schemas-upnp-org:service:Layer3Forwarding:1</serviceType><serviceId>urn:upnp-org:serviceId:Layer3Forwarding1</serviceId><controlURL>/ctl/L3F</controlURL><eventSubURL>/evt/L3F</eventSubURL><SCPDURL>/L3F.xml</SCPDURL></service><service><serviceType>urn:schemas-upnp-org:service:DeviceProtection:1</serviceType><serviceId>urn:upnp-org:serviceId:DeviceProtection1</serviceId><controlURL>/ctl/DP</controlURL><eventSubURL>/evt/DP</eventSubURL><SCPDURL>/DP.xml</SCPDURL></service></serviceList><deviceList><device><deviceType>urn:schemas-upnp-org:device:WANDevice:2</deviceType><friendlyName>WANDevice</friendlyName><manufacturer>MiniUPnP</manufacturer><manufacturerURL>http://miniupnp.free.fr/</manufacturerURL><modelDescription>WAN Device</modelDescription><modelName>WAN Device</modelName><modelNumber>20210414</modelNumber><modelURL>http://miniupnp.free.fr/</modelURL><serialNumber>00000000</serialNumber><UDN>uuid:a9708184-a6c0-413a-bbac-11bcf7e30ecf</UDN><UPC>000000000000</UPC><serviceList><service><serviceType>urn:schemas-upnp-org:service:WANCommonInterfaceConfig:1</serviceType><serviceId>urn:upnp-org:serviceId:WANCommonIFC1</serviceId><controlURL>/ctl/CmnIfCfg</controlURL><eventSubURL>/evt/CmnIfCfg</eventSubURL><SCPDURL>/WANCfg.xml</SCPDURL></service></serviceList><deviceList><device><deviceType>urn:schemas-upnp-org:device:WANConnectionDevice:2</deviceType><friendlyName>WANConnectionDevice</friendlyName><manufacturer>MiniUPnP</manufacturer><manufacturerURL>http://miniupnp.free.fr/</manufacturerURL><modelDescription>MiniUPnP daemon</modelDescription><modelName>MiniUPnPd</modelName><modelNumber>20210414</modelNumber><modelURL>http://miniupnp.free.fr/</modelURL><serialNumber>00000000</serialNumber><UDN>uuid:a9708184-a6c0-413a-bbac-11bcf7e30ec0</UDN><UPC>000000000000</UPC><serviceList><service><serviceType>urn:schemas-upnp-org:service:WANIPConnection:2</serviceType><serviceId>urn:upnp-org:serviceId:WANIPConn1</serviceId><controlURL>/ctl/IPConn</controlURL><eventSubURL>/evt/IPConn</eventSubURL><SCPDURL>/WANIPCn.xml</SCPDURL></service></serviceList></device></deviceList></device></deviceList><presentationURL>http://testwifi.here/</presentationURL></device></root>`
-)
-
-// pfSense 2.5.0-RELEASE / FreeBSD 12.2-STABLE
-const (
-	pfSenseUPnPDisco = "HTTP/1.1 200 OK\r\nCACHE-CONTROL: max-age=120\r\nST: urn:schemas-upnp-org:device:InternetGatewayDevice:1\r\nUSN: uuid:bee7052b-49e8-3597-b545-55a1e38ac11::urn:schemas-upnp-org:device:InternetGatewayDevice:1\r\nEXT:\r\nSERVER: FreeBSD/12.2-STABLE UPnP/1.1 MiniUPnPd/2.2.1\r\nLOCATION: http://192.168.1.1:2189/rootDesc.xml\r\nOPT: \"http://schemas.upnp.org/upnp/1/0/\"; ns=01\r\n01-NLS: 1627958564\r\nBOOTID.UPNP.ORG: 1627958564\r\nCONFIGID.UPNP.ORG: 1337\r\n\r\n"
-
-	pfSenseRootDescXML = `<?xml version="1.0"?>
-<root xmlns="urn:schemas-upnp-org:device-1-0" configId="1337"><specVersion><major>1</major><minor>1</minor></specVersion><device><deviceType>urn:schemas-upnp-org:device:InternetGatewayDevice:1</deviceType><friendlyName>FreeBSD router</friendlyName><manufacturer>FreeBSD</manufacturer><manufacturerURL>http://www.freebsd.org/</manufacturerURL><modelDescription>FreeBSD router</modelDescription><modelName>FreeBSD router</modelName><modelNumber>2.5.0-RELEASE</modelNumber><modelURL>http://www.freebsd.org/</modelURL><serialNumber>BEE7052B</serialNumber><UDN>uuid:bee7052b-49e8-3597-b545-55a1e38ac11</UDN><serviceList><service><serviceType>urn:schemas-upnp-org:service:Layer3Forwarding:1</serviceType><serviceId>urn:upnp-org:serviceId:L3Forwarding1</serviceId><SCPDURL>/L3F.xml</SCPDURL><controlURL>/ctl/L3F</controlURL><eventSubURL>/evt/L3F</eventSubURL></service></serviceList><deviceList><device><deviceType>urn:schemas-upnp-org:device:WANDevice:1</deviceType><friendlyName>WANDevice</friendlyName><manufacturer>MiniUPnP</manufacturer><manufacturerURL>http://miniupnp.free.fr/</manufacturerURL><modelDescription>WAN Device</modelDescription><modelName>WAN Device</modelName><modelNumber>20210205</modelNumber><modelURL>http://miniupnp.free.fr/</modelURL><serialNumber>BEE7052B</serialNumber><UDN>uuid:bee7052b-49e8-3597-b545-55a1e38ac12</UDN><UPC>000000000000</UPC><serviceList><service><serviceType>urn:schemas-upnp-org:service:WANCommonInterfaceConfig:1</serviceType><serviceId>urn:upnp-org:serviceId:WANCommonIFC1</serviceId><SCPDURL>/WANCfg.xml</SCPDURL><controlURL>/ctl/CmnIfCfg</controlURL><eventSubURL>/evt/CmnIfCfg</eventSubURL></service></serviceList><deviceList><device><deviceType>urn:schemas-upnp-org:device:WANConnectionDevice:1</deviceType><friendlyName>WANConnectionDevice</friendlyName><manufacturer>MiniUPnP</manufacturer><manufacturerURL>http://miniupnp.free.fr/</manufacturerURL><modelDescription>MiniUPnP daemon</modelDescription><modelName>MiniUPnPd</modelName><modelNumber>20210205</modelNumber><modelURL>http://miniupnp.free.fr/</modelURL><serialNumber>BEE7052B</serialNumber><UDN>uuid:bee7052b-49e8-3597-b545-55a1e38ac13</UDN><UPC>000000000000</UPC><serviceList><service><serviceType>urn:schemas-upnp-org:service:WANIPConnection:1</serviceType><serviceId>urn:upnp-org:serviceId:WANIPConn1</serviceId><SCPDURL>/WANIPCn.xml</SCPDURL><controlURL>/ctl/IPConn</controlURL><eventSubURL>/evt/IPConn</eventSubURL></service></serviceList></device></deviceList></device></deviceList><presentationURL>https://192.168.1.1/</presentationURL></device></root>`
-)
-
-func TestParseUPnPDiscoResponse(t *testing.T) {
-	tests := []struct {
-		name    string
-		headers string
-		want    uPnPDiscoResponse
-	}{
-		{"google", googleWifiUPnPDisco, uPnPDiscoResponse{
-			Location: "http://192.168.86.1:5000/rootDesc.xml",
-		}},
-		{"pfsense", pfSenseUPnPDisco, uPnPDiscoResponse{
-			Location: "http://192.168.1.1:2189/rootDesc.xml",
-		}},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, err := parseUPnPDiscoResponse([]byte(tt.headers))
-			if err != nil {
-				t.Fatal(err)
-			}
-			if !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("unexpected result:\n got: %+v\nwant: %+v\n", got, tt.want)
-			}
-		})
-	}
-}
-
-func TestGetUPnPClient(t *testing.T) {
-	tests := []struct {
-		name    string
-		xmlBody string
-		want    string
-	}{
-		{"google", googleWifiRootDescXML, "*internetgateway2.WANIPConnection2"},
-		{"pfsense", pfSenseRootDescXML, "*internetgateway2.WANIPConnection1"},
-		// TODO(bradfitz): find a PPP one in the wild
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-				if r.RequestURI == "/rootDesc.xml" {
-					io.WriteString(w, tt.xmlBody)
-					return
-				}
-				http.NotFound(w, r)
-			}))
-			defer ts.Close()
-			gw, _ := netaddr.FromStdIP(ts.Listener.Addr().(*net.TCPAddr).IP)
-			c, err := getUPnPClient(context.Background(), gw, uPnPDiscoResponse{
-				Location: ts.URL + "/rootDesc.xml",
-			})
-			if err != nil {
-				t.Fatal(err)
-			}
-			got := fmt.Sprintf("%T", c)
-			if got != tt.want {
-				t.Errorf("got %v; want %v", got, tt.want)
-			}
-		})
-	}
-}

net/speedtest/speedtest.go

@@ -1,88 +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 speedtest contains both server and client code for
-// running speedtests between tailscale nodes.
-package speedtest
-
-import (
-	"time"
-)
-
-const (
-	blockSize       = 32000                 // size of the block of data to send
-	MinDuration     = 5 * time.Second       // minimum duration for a test
-	DefaultDuration = MinDuration           // default duration for a test
-	MaxDuration     = 30 * time.Second      // maximum duration for a test
-	version         = 1                     // value used when comparing client and server versions
-	increment       = time.Second           // increment to display results for, in seconds
-	minInterval     = 10 * time.Millisecond // minimum interval length for a result to be included
-	DefaultPort     = 20333
-)
-
-// config is the initial message sent to the server, that contains information on how to
-// conduct the test.
-type config struct {
-	Version      int           `json:"version"`
-	TestDuration time.Duration `json:"time"`
-	Direction    Direction     `json:"direction"`
-}
-
-// configResponse is the response to the testConfig message. If the server has an
-// error with the config, the Error variable will hold that error value.
-type configResponse struct {
-	Error string `json:"error,omitempty"`
-}
-
-// This represents the Result of a speedtest within a specific interval
-type Result struct {
-	Bytes         int           // number of bytes sent/received during the interval
-	IntervalStart time.Duration // duration between the start of the interval and the start of the test
-	IntervalEnd   time.Duration // duration between the end of the interval and the start of the test
-	Total         bool          // if true, this result struct represents the entire test, rather than a segment of the test
-}
-
-func (r Result) MBitsPerSecond() float64 {
-	return r.MegaBits() / (r.IntervalEnd - r.IntervalStart).Seconds()
-}
-
-func (r Result) MegaBytes() float64 {
-	return float64(r.Bytes) / 1000000.0
-}
-
-func (r Result) MegaBits() float64 {
-	return r.MegaBytes() * 8.0
-}
-
-func (r Result) Interval() time.Duration {
-	return r.IntervalEnd - r.IntervalStart
-}
-
-type Direction int
-
-const (
-	Download Direction = iota
-	Upload
-)
-
-func (d Direction) String() string {
-	switch d {
-	case Upload:
-		return "upload"
-	case Download:
-		return "download"
-	default:
-		return ""
-	}
-}
-
-func (d *Direction) Reverse() {
-	switch *d {
-	case Upload:
-		*d = Download
-	case Download:
-		*d = Upload
-	default:
-	}
-}

net/speedtest/speedtest_client.go

@@ -1,42 +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 speedtest
-
-import (
-	"encoding/json"
-	"errors"
-	"net"
-	"time"
-)
-
-// RunClient dials the given address and starts a speedtest.
-// It returns any errors that come up in the tests.
-// If there are no errors in the test, it returns a slice of results.
-func RunClient(direction Direction, duration time.Duration, host string) ([]Result, error) {
-	conn, err := net.Dial("tcp", host)
-	if err != nil {
-		return nil, err
-	}
-
-	conf := config{TestDuration: duration, Version: version, Direction: direction}
-
-	defer conn.Close()
-	encoder := json.NewEncoder(conn)
-
-	if err = encoder.Encode(conf); err != nil {
-		return nil, err
-	}
-
-	var response configResponse
-	decoder := json.NewDecoder(conn)
-	if err = decoder.Decode(&response); err != nil {
-		return nil, err
-	}
-	if response.Error != "" {
-		return nil, errors.New(response.Error)
-	}
-
-	return doTest(conn, conf)
-}

net/speedtest/speedtest_server.go

@@ -1,158 +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 speedtest
-
-import (
-	"crypto/rand"
-	"encoding/json"
-	"errors"
-	"fmt"
-	"io"
-	"net"
-	"time"
-)
-
-// Serve starts up the server on a given host and port pair. It starts to listen for
-// connections and handles each one in a goroutine. Because it runs in an infinite loop,
-// this function only returns if any of the speedtests return with errors, or if the
-// listener is closed.
-func Serve(l net.Listener) error {
-	for {
-		conn, err := l.Accept()
-		if errors.Is(err, net.ErrClosed) {
-			return nil
-		}
-		if err != nil {
-			return err
-		}
-		err = handleConnection(conn)
-		if err != nil {
-			return err
-		}
-	}
-}
-
-// handleConnection handles the initial exchange between the server and the client.
-// It reads the testconfig message into a config struct. If any errors occur with
-// the testconfig (specifically, if there is a version mismatch), it will return those
-// errors to the client with a configResponse. After the exchange, it will start
-// the speed test.
-func handleConnection(conn net.Conn) error {
-	defer conn.Close()
-	var conf config
-
-	decoder := json.NewDecoder(conn)
-	err := decoder.Decode(&conf)
-	encoder := json.NewEncoder(conn)
-
-	// Both return and encode errors that occurred before the test started.
-	if err != nil {
-		encoder.Encode(configResponse{Error: err.Error()})
-		return err
-	}
-
-	// The server should always be doing the opposite of what the client is doing.
-	conf.Direction.Reverse()
-
-	if conf.Version != version {
-		err = fmt.Errorf("version mismatch! Server is version %d, client is version %d", version, conf.Version)
-		encoder.Encode(configResponse{Error: err.Error()})
-		return err
-	}
-
-	// Start the test
-	encoder.Encode(configResponse{})
-	_, err = doTest(conn, conf)
-	return err
-}
-
-// TODO include code to detect whether the code is direct vs DERP
-
-// doTest contains the code to run both the upload and download speedtest.
-// the direction value in the config parameter determines which test to run.
-func doTest(conn net.Conn, conf config) ([]Result, error) {
-	bufferData := make([]byte, blockSize)
-
-	intervalBytes := 0
-	totalBytes := 0
-
-	var currentTime time.Time
-	var results []Result
-
-	startTime := time.Now()
-	lastCalculated := startTime
-
-	if conf.Direction == Download {
-		conn.SetReadDeadline(time.Now().Add(conf.TestDuration).Add(5 * time.Second))
-	} else {
-		_, err := rand.Read(bufferData)
-		if err != nil {
-			return nil, err
-		}
-
-	}
-
-SpeedTestLoop:
-	for {
-		var n int
-		var err error
-
-		if conf.Direction == Download {
-			n, err = io.ReadFull(conn, bufferData)
-			switch err {
-			case io.EOF, io.ErrUnexpectedEOF:
-				break SpeedTestLoop
-			case nil:
-				// successful read
-			default:
-				return nil, fmt.Errorf("unexpected error has occured: %w", err)
-			}
-		} else {
-			// Need to change the data a little bit, to avoid any compression.
-			for i := range bufferData {
-				bufferData[i]++
-			}
-			n, err = conn.Write(bufferData)
-			if err != nil {
-				// If the write failed, there is most likely something wrong with the connection.
-				return nil, fmt.Errorf("upload failed: %w", err)
-			}
-		}
-		currentTime = time.Now()
-		intervalBytes += n
-
-		// checks if the current time is more or equal to the lastCalculated time plus the increment
-		if currentTime.After(lastCalculated.Add(increment)) {
-			intervalStart := lastCalculated.Sub(startTime)
-			intervalEnd := currentTime.Sub(startTime)
-			if (intervalEnd - intervalStart) > minInterval {
-				results = append(results, Result{Bytes: intervalBytes, IntervalStart: intervalStart, IntervalEnd: intervalEnd, Total: false})
-			}
-			lastCalculated = currentTime
-			totalBytes += intervalBytes
-			intervalBytes = 0
-		}
-
-		if conf.Direction == Upload && time.Since(startTime) > conf.TestDuration {
-			break SpeedTestLoop
-		}
-	}
-
-	// get last segment
-	intervalStart := lastCalculated.Sub(startTime)
-	intervalEnd := currentTime.Sub(startTime)
-	if (intervalEnd - intervalStart) > minInterval {
-		results = append(results, Result{Bytes: intervalBytes, IntervalStart: intervalStart, IntervalEnd: intervalEnd, Total: false})
-	}
-
-	// get total
-	totalBytes += intervalBytes
-	intervalEnd = currentTime.Sub(startTime)
-	if intervalEnd > minInterval {
-		results = append(results, Result{Bytes: totalBytes, IntervalStart: 0, IntervalEnd: intervalEnd, Total: true})
-	}
-
-	return results, nil
-}

net/speedtest/speedtest_test.go

@@ -1,81 +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 speedtest
-
-import (
-	"net"
-	"testing"
-)
-
-func TestDownload(t *testing.T) {
-	// start a listener and find the port where the server will be listening.
-	l, err := net.Listen("tcp", ":0")
-	if err != nil {
-		t.Fatal(err)
-	}
-	t.Cleanup(func() { l.Close() })
-
-	serverIP := l.Addr().String()
-	t.Log("server IP found:", serverIP)
-
-	type state struct {
-		err error
-	}
-	displayResult := func(t *testing.T, r Result) {
-		t.Helper()
-		t.Logf("{ Megabytes: %.2f, Start: %.1f, End: %.1f, Total: %t }", r.MegaBytes(), r.IntervalStart.Seconds(), r.IntervalEnd.Seconds(), r.Total)
-	}
-	stateChan := make(chan state, 1)
-
-	go func() {
-		err := Serve(l)
-		stateChan <- state{err: err}
-	}()
-
-	// ensure that the test returns an appropriate number of Result structs
-	expectedLen := int(DefaultDuration.Seconds()) + 1
-
-	t.Run("download test", func(t *testing.T) {
-		// conduct a download test
-		results, err := RunClient(Download, DefaultDuration, serverIP)
-
-		if err != nil {
-			t.Fatal("download test failed:", err)
-		}
-
-		if len(results) < expectedLen {
-			t.Fatalf("download results: expected length: %d, actual length: %d", expectedLen, len(results))
-		}
-
-		for _, result := range results {
-			displayResult(t, result)
-		}
-	})
-
-	t.Run("upload test", func(t *testing.T) {
-		// conduct an upload test
-		results, err := RunClient(Upload, DefaultDuration, serverIP)
-
-		if err != nil {
-			t.Fatal("upload test failed:", err)
-		}
-
-		if len(results) < expectedLen {
-			t.Fatalf("upload results: expected length: %d, actual length: %d", expectedLen, len(results))
-		}
-
-		for _, result := range results {
-			displayResult(t, result)
-		}
-	})
-
-	// causes the server goroutine to finish
-	l.Close()
-
-	testState := <-stateChan
-	if testState.err != nil {
-		t.Error("server error:", err)
-	}
-}

net/tsaddr/tsaddr.go

@@ -105,6 +105,11 @@ func Tailscale4To6(ipv4 netaddr.IP) netaddr.IP {
 	return netaddr.IPFrom16(ret)
 }
 
+func IsULA(ip netaddr.IP) bool {
+	ulaRange.Do(func() { mustPrefix(&ulaRange.v, "fc00::/7") })
+	return ulaRange.v.Contains(ip)
+}
+
 func mustPrefix(v *netaddr.IPPrefix, prefix string) {
 	var err error
 	*v, err = netaddr.ParseIPPrefix(prefix)

net/tsaddr/tsaddr_test.go

@@ -43,6 +43,28 @@ func TestCGNATRange(t *testing.T) {
 	}
 }
 
+func TestIsUla(t *testing.T) {
+	tests := []struct {
+		name string
+		ip   string
+		want bool
+	}{
+		{"first ULA", "fc00::1", true},
+		{"not ULA", "fb00::1", false},
+		{"Tailscale", "fd7a:115c:a1e0::1", true},
+		{"Cloud Run", "fddf:3978:feb1:d745::1", true},
+		{"zeros", "0000:0000:0000:0000:0000:0000:0000:0000", false},
+		{"Link Local", "fe80::1", false},
+		{"Global", "2602::1", false},
+	}
+
+	for _, test := range tests {
+		if got := IsULA(netaddr.MustParseIP(test.ip)); got != test.want {
+			t.Errorf("IsULA(%s) = %v, want %v", test.name, got, test.want)
+		}
+	}
+}
+
 func TestNewContainsIPFunc(t *testing.T) {
 	f := NewContainsIPFunc([]netaddr.IPPrefix{netaddr.MustParseIPPrefix("10.0.0.0/8")})
 	if f(netaddr.MustParseIP("8.8.8.8")) {

net/tstun/wrap.go

@@ -18,7 +18,7 @@ import (
 	"golang.zx2c4.com/wireguard/tun"
 	"inet.af/netaddr"
 	"tailscale.com/net/packet"
-	"tailscale.com/tstime/mono"
+	"tailscale.com/net/uring"
 	"tailscale.com/types/ipproto"
 	"tailscale.com/types/logger"
 	"tailscale.com/wgengine/filter"
@@ -65,7 +65,7 @@ type Wrapper struct {
 
 	closeOnce sync.Once
 
-	lastActivityAtomic mono.Time // time of last send or receive
+	lastActivityAtomic int64 // unix seconds of last send or receive
 
 	destIPActivity atomic.Value // of map[netaddr.IP]func()
 
@@ -154,19 +154,28 @@ func Wrap(logf logger.Logf, tdev tun.Device) *Wrapper {
 		// a goroutine should not block when setting it, even with no listeners.
 		bufferConsumed: make(chan struct{}, 1),
 		closed:         make(chan struct{}),
-		// outbound can be unbuffered; the buffer is an optimization.
-		outbound:     make(chan tunReadResult, 1),
-		eventsUpDown: make(chan tun.Event),
-		eventsOther:  make(chan tun.Event),
+		outbound:       make(chan tunReadResult),
+		eventsUpDown:   make(chan tun.Event),
+		eventsOther:    make(chan tun.Event),
 		// TODO(dmytro): (highly rate-limited) hexdumps should happen on unknown packets.
 		filterFlags: filter.LogAccepts | filter.LogDrops,
 	}
 
+	if uring.Available() {
+		uringTun, err := uring.NewTUN(tdev)
+		name, _ := tdev.Name()
+		if err != nil {
+			logf("not using io_uring for TUN %v: %v", name, err)
+		} else {
+			logf("using uring for TUN %v", name)
+			tdev = uringTun
+		}
+	}
+
 	go tun.poll()
 	go tun.pumpEvents()
 	// The buffer starts out consumed.
 	tun.bufferConsumed <- struct{}{}
-	tun.noteActivity()
 
 	return tun
 }
@@ -366,15 +375,16 @@ func (t *Wrapper) filterOut(p *packet.Parsed) filter.Response {
 
 // noteActivity records that there was a read or write at the current time.
 func (t *Wrapper) noteActivity() {
-	t.lastActivityAtomic.StoreAtomic(mono.Now())
+	atomic.StoreInt64(&t.lastActivityAtomic, time.Now().Unix())
 }
 
 // IdleDuration reports how long it's been since the last read or write to this device.
 //
-// Its value should only be presumed accurate to roughly 10ms granularity.
-// If there's never been activity, the duration is since the wrapper was created.
+// Its value is only accurate to roughly second granularity.
+// If there's never been activity, the duration is since 1970.
 func (t *Wrapper) IdleDuration() time.Duration {
-	return mono.Since(t.lastActivityAtomic.LoadAtomic())
+	sec := atomic.LoadInt64(&t.lastActivityAtomic)
+	return time.Since(time.Unix(sec, 0))
 }
 
 func (t *Wrapper) Read(buf []byte, offset int) (int, error) {

net/tstun/wrap_test.go

@@ -10,13 +10,13 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+	"sync/atomic"
 	"testing"
 	"unsafe"
 
 	"golang.zx2c4.com/wireguard/tun/tuntest"
 	"inet.af/netaddr"
 	"tailscale.com/net/packet"
-	"tailscale.com/tstime/mono"
 	"tailscale.com/types/ipproto"
 	"tailscale.com/types/logger"
 	"tailscale.com/wgengine/filter"
@@ -335,9 +335,9 @@ func TestFilter(t *testing.T) {
 				// data was actually filtered.
 				// If it stays zero, nothing made it through
 				// to the wrapped TUN.
-				tun.lastActivityAtomic.StoreAtomic(0)
+				atomic.StoreInt64(&tun.lastActivityAtomic, 0)
 				_, err = tun.Write(tt.data, 0)
-				filtered = tun.lastActivityAtomic.LoadAtomic() == 0
+				filtered = atomic.LoadInt64(&tun.lastActivityAtomic) == 0
 			} else {
 				chtun.Outbound <- tt.data
 				n, err = tun.Read(buf[:], 0)
@@ -416,7 +416,7 @@ func TestAtomic64Alignment(t *testing.T) {
 	}
 
 	c := new(Wrapper)
-	c.lastActivityAtomic.StoreAtomic(mono.Now())
+	atomic.StoreInt64(&c.lastActivityAtomic, 123)
 }
 
 func TestPeerAPIBypass(t *testing.T) {

net/uring/all.go

@@ -0,0 +1,12 @@
+// Package uring provides a net.PacketConn and tun.Device that use io_uring for I/O.
+package uring
+
+import "runtime"
+
+// This file contains code shared across all platforms.
+
+// Available reports whether io_uring is available on this machine.
+// If Available reports false, no other package uring APIs should be called.
+func Available() bool {
+	return runtime.GOOS == "linux"
+}

net/uring/capability_linux.go

@@ -0,0 +1,26 @@
+package uring
+
+// #cgo CFLAGS: -I${SRCDIR}/liburing/src/include
+// #cgo LDFLAGS: -L${SRCDIR}/liburing/src/ -luring
+// #include "io_uring_linux.c"
+import "C"
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// hasUring reports whether it is possible to use io_uring syscalls on the system.
+func uringSupported() bool {
+	probe, err := C.io_uring_get_probe()
+	if err == nil && probe != nil {
+		C.free(unsafe.Pointer(probe))
+	}
+	return err != syscall.ENOSYS
+}
+
+// If/when we want to probe for specific io_uring capabilities,
+// rather than just the presence of the syscalls,
+// this code by Julian Knodt might be handy:
+// https://gist.github.com/JulianKnodt/e7030739d163f5251eb47f8ac1d67b62
+// (See discussion in https://github.com/tailscale/tailscale/pull/2371.)

net/uring/file_linux.go

@@ -0,0 +1,202 @@
+package uring
+
+// #cgo LDFLAGS: -luring
+// #include "io_uring_linux.c"
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"time"
+	"unsafe"
+
+	"tailscale.com/syncs"
+)
+
+// A file is a file handle that uses io_uring for reads and writes.
+// It is intended for use with TUN fds, and thus only supports
+// reading from and writing to file offset 0.
+type file struct {
+	// We have two urings so that we don't have to demux completion events.
+
+	// writeRing is the uring for pwritev calls.
+	writeRing writeRing
+	// readRing is the uring for preadv calls.
+	readRing *C.go_uring
+
+	// close ensures that file closes occur exactly once.
+	close sync.Once
+	// closed indicates whether the file has been closed.
+	closed syncs.AtomicBool
+	// shutdown is a sequence of funcs to be called when the UDPConn closes.
+	shutdown []func()
+
+	// file is the os file underlying this file.
+	file *os.File
+
+	// readReqs is an array of re-usable file preadv requests.
+	// We attempt to keep them all queued up for the kernel to fulfill.
+	// The array length is tied to the size of the uring.
+	readReqs [1]*C.goreq // Whoops! The kernel apparently cannot handle more than 1 concurrent preadv calls on a tun device!
+
+	// refcount counts the number of outstanding read/write requests.
+	// See the length comment for UDPConn.refcount for details.
+	refcount syncs.AtomicInt32
+}
+
+func newFile(f *os.File) (*file, error) {
+	u := &file{
+		readRing: new(C.go_uring),
+		file:     f,
+	}
+	u.writeRing.ring = new(C.go_uring)
+
+	fd := f.Fd()
+	if ret := C.initialize(u.readRing, C.int(fd)); ret < 0 {
+		u.doShutdown()
+		return nil, fmt.Errorf("readRing initialization failed: %w", syscall.Errno(-ret))
+	}
+	u.shutdown = append(u.shutdown, func() {
+		C.io_uring_queue_exit(u.readRing)
+	})
+
+	if ret := C.initialize(u.writeRing.ring, C.int(fd)); ret < 0 {
+		u.doShutdown()
+		return nil, fmt.Errorf("writeRing initialization failed: %w", syscall.Errno(-ret))
+	}
+	u.shutdown = append(u.shutdown, func() {
+		C.io_uring_queue_exit(u.writeRing.ring)
+	})
+
+	// Initialize buffers
+	for i := range &u.readReqs {
+		u.readReqs[i] = C.initializeReq(bufferSize, C.size_t(i), 0) // 0: not used for IP addresses
+	}
+	u.writeRing.initReqs(0) // 0: not used for IP addresses
+	u.shutdown = append(u.shutdown, func() {
+		for _, r := range u.readReqs {
+			C.freeReq(r)
+		}
+		u.writeRing.freeReqs()
+	})
+
+	// Initialize read half.
+	for i := range u.readReqs {
+		if err := u.submitReadvRequest(i); err != nil {
+			u.doShutdown()
+			return nil, err
+		}
+	}
+
+	// Initialization succeeded.
+	// Take ownership of the file.
+	u.shutdown = append(u.shutdown, func() {
+		u.file.Close()
+	})
+	return u, nil
+}
+
+func (u *file) submitReadvRequest(idx int) error {
+	errno := C.submit_readv_request(u.readRing, u.readReqs[idx])
+	if errno < 0 {
+		return fmt.Errorf("uring.submitReadvRequest failed: %w", syscall.Errno(-errno))
+	}
+	atomic.AddInt32(u.readReqInKernel(idx), 1) // TODO: CAS?
+	return nil
+}
+
+func (u *file) readReqInKernel(idx int) *int32 {
+	return (*int32)(unsafe.Pointer(&u.readReqs[idx].in_kernel))
+}
+
+// Read data into buf.
+func (u *file) Read(buf []byte) (n int, err error) {
+	// The docs for the u.refcount field document this prologue.
+	u.refcount.Add(1)
+	defer u.refcount.Add(-1)
+	if u.closed.Get() {
+		return 0, os.ErrClosed
+	}
+
+	n, idx, err := waitCompletion(u.readRing)
+	if errors.Is(err, syscall.ECANCELED) {
+		atomic.AddInt32(u.readReqInKernel(idx), -1)
+		return 0, os.ErrClosed
+	}
+	if err != nil {
+		return 0, fmt.Errorf("Read: io_uring failed to issue syscall: %w", err)
+	}
+	atomic.AddInt32(u.readReqInKernel(idx), -1)
+	if n < 0 {
+		// io_uring ran our syscall, which failed.
+		// Best effort attempt not to leak idx.
+		u.submitReadvRequest(int(idx))
+		return 0, fmt.Errorf("Read: syscall failed: %w", syscall.Errno(-n))
+	}
+	// Success.
+	r := u.readReqs[idx]
+	rbuf := sliceOf(r.buf, n)
+	copy(buf, rbuf)
+	// Queue up a new request.
+	if err := u.submitReadvRequest(int(idx)); err != nil {
+		// Aggressively return this error.
+		return 0, err
+	}
+	return n, nil
+}
+
+func (u *file) Write(buf []byte) (int, error) {
+	// The docs for the u.refcount field document this prologue.
+	u.refcount.Add(1)
+	defer u.refcount.Add(-1)
+	if u.closed.Get() {
+		return 0, os.ErrClosed
+	}
+
+	// Get a req, blocking as needed.
+	r, err := u.writeRing.getReq()
+	if err != nil {
+		return 0, err
+	}
+	// Do the write.
+	rbuf := sliceOf(r.buf, len(buf))
+	copy(rbuf, buf)
+	C.submit_writev_request(u.writeRing.ring, r, C.int(len(buf)))
+	// Get an extra buffer, if available.
+	u.writeRing.prefetch()
+	return len(buf), nil
+}
+
+func (u *file) Close() error {
+	u.close.Do(func() {
+		// Announce to readers and writers that we are closing down.
+		// Busy loop until all reads and writes are unblocked.
+		// See the docs for u.refcount.
+		u.closed.Set(true)
+		for {
+			// Request that the kernel cancel all submitted reads. (Writes don't block indefinitely.)
+			for idx := range u.readReqs {
+				if atomic.LoadInt32(u.readReqInKernel(idx)) != 0 {
+					C.submit_cancel_request(u.readRing, C.size_t(idx))
+				}
+			}
+			if u.refcount.Get() == 0 {
+				break
+			}
+			time.Sleep(time.Millisecond)
+		}
+		// Do the rest of the shutdown.
+		u.doShutdown()
+	})
+	return nil
+}
+
+func (u *file) doShutdown() {
+	for _, fn := range u.shutdown {
+		fn()
+	}
+}

net/uring/file_test_linux.go

@@ -0,0 +1,33 @@
+package uring
+
+import (
+	"os"
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+)
+
+func TestFileRead(t *testing.T) {
+	if !Available() {
+		t.Skip("io_uring not available")
+	}
+	c := qt.New(t)
+
+	const path = "testdata/voltaire.txt"
+	want, err := os.ReadFile(path)
+	c.Assert(err, qt.IsNil)
+
+	f, err := os.Open(path)
+	c.Assert(err, qt.IsNil)
+	t.Cleanup(func() { f.Close() })
+
+	uf, err := newFile(f)
+	if err != nil {
+		t.Skipf("io_uring not available: %v", err)
+	}
+	t.Cleanup(func() { uf.Close() })
+	buf := make([]byte, len(want)+128)
+	n, err := uf.Read(buf)
+	c.Assert(err, qt.IsNil)
+	c.Assert(buf[:n], qt.DeepEquals, want)
+}

net/uring/io_uring_linux.c

@@ -0,0 +1,157 @@
+#include <arpa/inet.h> // debugging
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <liburing.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/udp.h>
+
+// TODO: use fixed buffers? https://unixism.net/loti/tutorial/fixed_buffers.html
+
+typedef struct io_uring go_uring;
+typedef struct msghdr go_msghdr;
+typedef struct iovec go_iovec;
+typedef struct sockaddr_in go_sockaddr_in;
+typedef struct io_uring_params go_io_uring_params;
+
+static int initialize(struct io_uring *ring, int fd) {
+    int ret = io_uring_queue_init(16, ring, 0); // 16: size of ring
+    if (ret < 0) {
+        return ret;
+    }
+    ret = io_uring_register_files(ring, &fd, 1);
+    // TODO: Do we need to unregister files on close, or is Closing the uring enough?
+    if (ret < 0) {
+        perror("io_uring_queue_init");
+        return ret;
+    }
+    return 0;
+}
+
+struct req {
+    struct msghdr hdr;
+	struct iovec iov;
+    struct sockaddr_in sa;
+    struct sockaddr_in6 sa6;
+    // in_kernel indicates (by being non-zero) whether this request is sitting in the kernel
+    // It is accessed atomically.
+    int32_t in_kernel; 
+    char *buf;
+    size_t idx;
+};
+
+typedef struct req goreq;
+
+static struct req *initializeReq(size_t sz, size_t idx, int ipLen) {
+    struct req *r = malloc(sizeof(struct req));
+    memset(r, 0, sizeof(*r));
+    r->buf = malloc(sz);
+    memset(r->buf, 0, sz);
+    r->iov.iov_base = r->buf;
+    r->iov.iov_len = sz;
+    r->hdr.msg_iov = &r->iov;
+    r->hdr.msg_iovlen = 1;
+    r->idx = idx;
+    switch(ipLen) {
+        case 4:
+            r->hdr.msg_name = &r->sa;
+            r->hdr.msg_namelen = sizeof(r->sa);
+            break;
+        case 16:
+            r->hdr.msg_name = &r->sa6;
+            r->hdr.msg_namelen = sizeof(r->sa6);
+            break;
+    }
+    return r;
+}
+
+static void freeReq(struct req *r) {
+    free(r->buf);
+    free(r);
+}
+
+// submit a recvmsg request via liburing
+// TODO: What recvfrom support arrives, maybe use that instead?
+static int submit_recvmsg_request(struct io_uring *ring, struct req *r) {
+    struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
+    io_uring_prep_recvmsg(sqe, 0, &r->hdr, 0); // use the 0th file in the list of registered fds
+    io_uring_sqe_set_flags(sqe, IOSQE_FIXED_FILE);
+    io_uring_sqe_set_data(sqe, (void *)(r->idx));
+    io_uring_submit(ring);
+    return 0;
+}
+
+// submit a recvmsg request via liburing
+// TODO: What recvfrom support arrives, maybe use that instead?
+static int submit_sendmsg_request(struct io_uring *ring, struct req *r, int buflen) {
+    r->iov.iov_len = buflen;
+    struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
+    io_uring_prep_sendmsg(sqe, 0, &r->hdr, 0); // use the 0th file in the list of registered fds
+    io_uring_sqe_set_flags(sqe, IOSQE_FIXED_FILE);
+    io_uring_sqe_set_data(sqe, (void *)(r->idx));
+    io_uring_submit(ring);
+    return 0;
+}
+
+static void submit_cancel_request(struct io_uring *ring, size_t idx) {
+    struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
+	io_uring_prep_cancel(sqe, (void *)(idx), 0);
+    io_uring_submit(ring);
+}
+
+// submit a writev request via liburing
+static int submit_writev_request(struct io_uring *ring, struct req *r, int buflen) {
+    r->iov.iov_len = buflen;
+    struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
+    io_uring_prep_writev(sqe, 0, &r->iov, 1, 0); // use the 0th file in the list of registered fds
+    io_uring_sqe_set_flags(sqe, IOSQE_FIXED_FILE);
+    io_uring_sqe_set_data(sqe, (void *)(r->idx));
+    int submitted = io_uring_submit(ring);
+    return 0;
+}
+
+// submit a readv request via liburing
+static int submit_readv_request(struct io_uring *ring, struct req *r) {
+    struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
+    io_uring_prep_readv(sqe, 0, &r->iov, 1, 0); // use the 0th file in the list of registered fds
+    io_uring_sqe_set_flags(sqe, IOSQE_FIXED_FILE);
+    io_uring_sqe_set_data(sqe, (void *)(r->idx));
+    int submitted = io_uring_submit(ring);
+    return 0;
+}
+
+
+struct completion_result {
+    int err;
+    int n;
+    size_t idx;
+};
+
+typedef struct completion_result go_completion_result;
+
+static go_completion_result completion(struct io_uring *ring, int block) {
+    struct io_uring_cqe *cqe;
+    struct completion_result res;
+    res.err = 0;
+    res.n = 0;
+    res.idx = 0;
+    if (block) {
+        res.err = io_uring_wait_cqe(ring, &cqe);
+    } else {
+        res.err = io_uring_peek_cqe(ring, &cqe);
+    }
+    if (res.err < 0) {
+        return res;
+    }
+    res.idx = (size_t)io_uring_cqe_get_data(cqe);
+    res.n = cqe->res;
+    io_uring_cqe_seen(ring, cqe);
+    return res;
+}

net/uring/io_uring_linux.go

@@ -0,0 +1,118 @@
+package uring
+
+// #cgo LDFLAGS: -luring
+// #include "io_uring_linux.c"
+import "C"
+
+import (
+	"fmt"
+	"reflect"
+	"syscall"
+	"unsafe"
+)
+
+// A writeRing is an io_uring usable for sendmsg or pwritev calls.
+// It manages an array of re-usable buffers.
+type writeRing struct {
+	ring *C.go_uring
+	// reqs is an array of re-usable write requests.
+	// We dispatch them to the kernel as writes are requested.
+	// The array length is tied to the size of the uring.
+	reqs [8]*C.goreq
+	// reqC is a channel containing indices into reqs
+	// that are free to use (that is, not in the kernel).
+	reqC chan int
+}
+
+// initReqs initializes r's reqs so that they can be used for writes/sends.
+func (r *writeRing) initReqs(ipLen int) {
+	for i := range &r.reqs {
+		r.reqs[i] = C.initializeReq(bufferSize, C.size_t(i), C.int(ipLen))
+	}
+	r.reqC = make(chan int, len(r.reqs))
+	for i := range r.reqs {
+		r.reqC <- i
+	}
+}
+
+// getReq gets a req usable for a write/send.
+// It blocks until such a req is available.
+func (r *writeRing) getReq() (req *C.goreq, err error) {
+	var idx int
+	select {
+	case idx = <-r.reqC:
+	default:
+		// No request available. Get one from the kernel.
+		n, idx, err := waitCompletion(r.ring)
+		if err != nil {
+			return nil, fmt.Errorf("Write io_uring call failed: %w", err)
+		}
+		if n < 0 {
+			// Past syscall failed.
+			r.reqC <- idx // don't leak idx
+			return nil, fmt.Errorf("previous Write failed: %w", syscall.Errno(-n))
+		}
+	}
+	return r.reqs[idx], nil
+}
+
+// prefetch attempts to fetch a req for use by future writes.
+// It does not block.
+// TODO: does this actually buy us anything?
+// TODO: return errors encountered here, rather than delaying them until later?
+func (r *writeRing) prefetch() {
+	idx, ok := peekCompletion(r.ring)
+	if ok {
+		// Put the request buffer back in the usable queue.
+		// Should never block, by construction.
+		r.reqC <- idx
+	}
+}
+
+// freeReqs frees the reqs allocated by initReqs.
+func (r *writeRing) freeReqs() {
+	for _, req := range r.reqs {
+		C.freeReq(req)
+	}
+}
+
+const (
+	noBlockForCompletion = 0
+	blockForCompletion   = 1
+)
+
+// waitCompletion blocks until a completion on ring succeeds, or until *fd == 0.
+// If *fd == 0, that indicates that the ring is no loner valid, in which case waitCompletion returns net.ErrClosed.
+// Reads of *fd are atomic.
+func waitCompletion(ring *C.go_uring) (n, idx int, err error) {
+	for {
+		r := C.completion(ring, blockForCompletion)
+		if syscall.Errno(-r.err) == syscall.EAGAIN || syscall.Errno(-r.err) == syscall.EINTR {
+			continue
+		}
+		var err error
+		if r.err < 0 {
+			err = syscall.Errno(-r.err)
+		}
+		return int(r.n), int(r.idx), err
+	}
+}
+
+func peekCompletion(ring *C.go_uring) (idx int, ok bool) {
+	r := C.completion(ring, noBlockForCompletion)
+	if r.err < 0 {
+		return 0, false
+	}
+	return int(r.idx), true
+}
+
+// sliceOf returns ptr[:n] as a byte slice.
+// TODO: replace with unsafe.Slice once we are using Go 1.17.
+func sliceOf(ptr *C.char, n int) []byte {
+	var b []byte
+	h := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	h.Data = uintptr(unsafe.Pointer(ptr))
+	h.Len = n
+	h.Cap = n
+	return b
+}

net/uring/io_uring_test.go

@@ -0,0 +1,11 @@
+// +build linux
+
+package uring
+
+import (
+	"testing"
+)
+
+func TestUringAvailable(t *testing.T) {
+	uringSupported()
+}

net/uring/stubs.go

@@ -0,0 +1,27 @@
+// +build !linux
+
+package uring
+
+import (
+	"net"
+	"time"
+
+	"golang.zx2c4.com/wireguard/tun"
+	"inet.af/netaddr"
+)
+
+// This file contains stubs for platforms that are known at compile time not to support io_uring.
+
+type UDPConn struct{}
+
+func NewUDPConn(net.PacketConn) (*UDPConn, error)                      { panic("io_uring unavailable") }
+func (u *UDPConn) ReadFromNetaddr([]byte) (int, netaddr.IPPort, error) { panic("io_uring unavailable") }
+func (u *UDPConn) Close() error                                        { panic("io_uring unavailable") }
+func (c *UDPConn) ReadFrom([]byte) (int, net.Addr, error)              { panic("io_uring unavailable") }
+func (u *UDPConn) WriteTo([]byte, net.Addr) (int, error)               { panic("io_uring unavailable") }
+func (c *UDPConn) LocalAddr() net.Addr                                 { panic("io_uring unavailable") }
+func (c *UDPConn) SetDeadline(time.Time) error                         { panic("io_uring unavailable") }
+func (c *UDPConn) SetReadDeadline(time.Time) error                     { panic("io_uring unavailable") }
+func (c *UDPConn) SetWriteDeadline(time.Time) error                    { panic("io_uring unavailable") }
+
+func NewTUN(tun.Device) (tun.Device, error) { panic("io_uring unavailable") }

net/uring/testdata/voltaire.txt

@@ -0,0 +1 @@
+If io_uring did not exist, it would be necessary to invent it.

net/uring/tun_linux.go

@@ -0,0 +1,104 @@
+package uring
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"reflect"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/net/ipv6"
+	"golang.zx2c4.com/wireguard/tun"
+)
+
+// Wrap files into TUN devices.
+
+func NewTUN(d tun.Device) (tun.Device, error) {
+	nt, ok := d.(*tun.NativeTun)
+	if !ok {
+		return nil, fmt.Errorf("NewTUN only wraps *tun.NativeTun, got %T", d)
+	}
+	f, err := newFile(nt.File())
+	if err != nil {
+		return nil, err
+	}
+	v := reflect.ValueOf(nt)
+	field, ok := v.Elem().Type().FieldByName("errors")
+	if !ok {
+		return nil, errors.New("could not find internal tun.NativeTun errors field")
+	}
+	ptr := unsafe.Pointer(nt)
+	ptr = unsafe.Pointer(uintptr(ptr) + field.Offset) // TODO: switch to unsafe.Add with Go 1.17...as if that's the worst thing in this line
+	c := *(*chan error)(ptr)
+	return &TUN{d: nt, f: f, errors: c}, nil
+}
+
+// No nopi
+type TUN struct {
+	d      *tun.NativeTun
+	f      *file
+	errors chan error
+}
+
+func (t *TUN) File() *os.File {
+	return t.f.file
+}
+
+func (t *TUN) Read(buf []byte, offset int) (int, error) {
+	select {
+	case err := <-t.errors:
+		return 0, err
+	default:
+	}
+	// TODO: upstream has graceful shutdown error handling here.
+	buff := buf[offset-4:]
+	n, err := t.f.Read(buff[:])
+	if errors.Is(err, syscall.EBADFD) {
+		err = os.ErrClosed
+	}
+	if n < 4 {
+		n = 0
+	} else {
+		n -= 4
+	}
+	return n, err
+}
+
+func (t *TUN) Write(buf []byte, offset int) (int, error) {
+	// below copied from wireguard-go NativeTun.Write
+
+	// reserve space for header
+	buf = buf[offset-4:]
+
+	// add packet information header
+	buf[0] = 0x00
+	buf[1] = 0x00
+	if buf[4]>>4 == ipv6.Version {
+		buf[2] = 0x86
+		buf[3] = 0xdd
+	} else {
+		buf[2] = 0x08
+		buf[3] = 0x00
+	}
+
+	n, err := t.f.Write(buf)
+	if errors.Is(err, syscall.EBADFD) {
+		err = os.ErrClosed
+	}
+	return n, err
+}
+
+func (t *TUN) Flush() error           { return t.d.Flush() }
+func (t *TUN) MTU() (int, error)      { return t.d.MTU() }
+func (t *TUN) Name() (string, error)  { return t.d.Name() }
+func (t *TUN) Events() chan tun.Event { return t.d.Events() }
+
+func (t *TUN) Close() error {
+	err1 := t.f.Close()
+	err2 := t.d.Close()
+	if err1 != nil {
+		return err1
+	}
+	return err2
+}

net/uring/udp_linux.go

@@ -0,0 +1,306 @@
+package uring
+
+// #cgo LDFLAGS: -luring
+// #include "io_uring_linux.c"
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"os"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"time"
+	"unsafe"
+
+	"golang.zx2c4.com/wireguard/device"
+	"inet.af/netaddr"
+	"tailscale.com/syncs"
+	"tailscale.com/util/endian"
+)
+
+const bufferSize = device.MaxSegmentSize
+
+// A UDPConn is a UDP connection that uses io_uring to send and receive packets.
+type UDPConn struct {
+	// We have two urings so that we don't have to demux completion events.
+
+	// recvRing is the uring for recvmsg calls.
+	recvRing *C.go_uring
+	// sendRing is the uring for sendmsg calls.
+	sendRing writeRing
+
+	// close ensures that connection closes occur exactly once.
+	close sync.Once
+	// closed indicates whether the connection has been closed.
+	closed syncs.AtomicBool
+	// shutdown is a sequence of funcs to be called when the UDPConn closes.
+	shutdown []func()
+
+	// file is the os file underlying this connection.
+	file *os.File
+	// local is the local address of this UDPConn.
+	local net.Addr
+	// is4 indicates whether the conn is an IPv4 connection.
+	is4 bool
+
+	// recvReqs is an array of re-usable UDP recvmsg requests.
+	// We attempt to keep them all queued up for the kernel to fulfill.
+	// The array length is tied to the size of the uring.
+	recvReqs [8]*C.goreq
+	// sendReqs is an array of re-usable UDP sendmsg requests.
+	// We dispatch them to the kernel as writes are requested.
+	// The array length is tied to the size of the uring.
+	sendReqs [8]*C.goreq
+	// sendReqC is a channel containing indices into sendReqs
+	// that are free to use (that is, not in the kernel).
+	sendReqC chan int
+
+	// refcount counts the number of outstanding read/write requests.
+	// refcount is used for graceful shutdown.
+	// The pattern (very roughly) is:
+	//
+	//   func readOrWrite() {
+	//     refcount++
+	//     defer refcount--
+	//     if closed {
+	//       return
+	//     }
+	//     // ...
+	//   }
+	//
+	// Close sets closed to true and polls until refcount hits zero.
+	// Once refcount hits zero, there are no ongoing reads or writes.
+	// Any future reads or writes will exit immediately (because closed is true),
+	// so resources used by reads and writes may be freed.
+	// The polling is unfortunate, but it occurs only during Close, is fast,
+	// and avoids ugly sequencing issues around canceling outstanding io_uring submissions.
+	//
+	// (The obvious alternative is to use a sync.RWMutex, but that has a chicken-and-egg problem.
+	// Reads/writes must take an rlock, but Close cannot take a wlock under all the rlocks are released,
+	// but Close cannot issue cancellations to release the rlocks without first taking a wlock.)
+	refcount syncs.AtomicInt32
+}
+
+func NewUDPConn(pconn net.PacketConn) (*UDPConn, error) {
+	conn, ok := pconn.(*net.UDPConn)
+	if !ok {
+		return nil, fmt.Errorf("cannot use io_uring with conn of type %T", pconn)
+	}
+	local := conn.LocalAddr()
+	udpAddr, ok := local.(*net.UDPAddr)
+	if !ok {
+		return nil, fmt.Errorf("cannot use io_uring with conn.LocalAddr of type %T", local)
+	}
+
+	// TODO: probe for system capabilities: https://unixism.net/loti/tutorial/probe_liburing.html
+
+	file, err := conn.File()
+	if err != nil {
+		return nil, err
+	}
+	// conn.File dup'd the conn's fd. We no longer need the original conn.
+	conn.Close()
+
+	u := &UDPConn{
+		recvRing: new(C.go_uring),
+		file:     file,
+		local:    local,
+		is4:      len(udpAddr.IP) == 4,
+	}
+	u.sendRing.ring = new(C.go_uring)
+
+	fd := file.Fd()
+	u.shutdown = append(u.shutdown, func() {
+		file.Close()
+	})
+
+	if ret := C.initialize(u.recvRing, C.int(fd)); ret < 0 {
+		u.doShutdown()
+		return nil, fmt.Errorf("recvRing initialization failed: %w", syscall.Errno(-ret))
+	}
+	u.shutdown = append(u.shutdown, func() {
+		C.io_uring_queue_exit(u.recvRing)
+	})
+
+	if ret := C.initialize(u.sendRing.ring, C.int(fd)); ret < 0 {
+		u.doShutdown()
+		return nil, fmt.Errorf("sendRing initialization failed: %w", syscall.Errno(-ret))
+	}
+	u.shutdown = append(u.shutdown, func() {
+		C.io_uring_queue_exit(u.sendRing.ring)
+	})
+
+	// Initialize buffers
+	for i := range u.recvReqs {
+		u.recvReqs[i] = C.initializeReq(bufferSize, C.size_t(i), C.int(len(udpAddr.IP)))
+	}
+	u.sendRing.initReqs(len(udpAddr.IP))
+	u.shutdown = append(u.shutdown, func() {
+		for _, r := range u.recvReqs {
+			C.freeReq(r)
+		}
+		u.sendRing.freeReqs()
+	})
+
+	// Initialize recv half.
+	for i := range u.recvReqs {
+		if err := u.submitRecvRequest(i); err != nil {
+			u.doShutdown()
+			return nil, err
+		}
+	}
+	return u, nil
+}
+
+func (u *UDPConn) submitRecvRequest(idx int) error {
+	errno := C.submit_recvmsg_request(u.recvRing, u.recvReqs[idx])
+	if errno < 0 {
+		return fmt.Errorf("uring.submitRecvRequest failed: %w", syscall.Errno(-errno))
+	}
+	atomic.AddInt32(u.recvReqInKernel(idx), 1) // TODO: CAS?
+	return nil
+}
+
+func (u *UDPConn) recvReqInKernel(idx int) *int32 {
+	return (*int32)(unsafe.Pointer(&u.recvReqs[idx].in_kernel))
+}
+
+func (u *UDPConn) ReadFromNetaddr(buf []byte) (int, netaddr.IPPort, error) {
+	// The docs for the u.refcount field document this prologue.
+	u.refcount.Add(1)
+	defer u.refcount.Add(-1)
+	if u.closed.Get() {
+		return 0, netaddr.IPPort{}, net.ErrClosed
+	}
+
+	n, idx, err := waitCompletion(u.recvRing)
+	if errors.Is(err, syscall.ECANCELED) {
+		atomic.AddInt32(u.recvReqInKernel(idx), -1)
+		return 0, netaddr.IPPort{}, net.ErrClosed
+	}
+	if err != nil {
+		// io_uring failed to run our syscall.
+		return 0, netaddr.IPPort{}, fmt.Errorf("ReadFromNetaddr io_uring could not run syscall: %w", err)
+	}
+	atomic.AddInt32(u.recvReqInKernel(idx), -1)
+	if n < 0 {
+		// io_uring ran our syscall, which failed.
+		// Best effort attempt not to leak idx.
+		u.submitRecvRequest(int(idx))
+		return 0, netaddr.IPPort{}, fmt.Errorf("ReadFromNetaddr syscall failed: %w", syscall.Errno(-n))
+	}
+	r := u.recvReqs[idx]
+	var ip netaddr.IP
+	var port uint16
+	if u.is4 {
+		ip = netaddr.IPFrom4(*(*[4]byte)((unsafe.Pointer)((&r.sa.sin_addr.s_addr))))
+		port = endian.Ntoh16(uint16(r.sa.sin_port))
+	} else {
+		ip = netaddr.IPFrom16(*(*[16]byte)((unsafe.Pointer)((&r.sa6.sin6_addr))))
+		port = endian.Ntoh16(uint16(r.sa6.sin6_port))
+	}
+	ipp := netaddr.IPPortFrom(ip, port)
+	// Copy the data to the buffer provided by wireguard-go.
+	// Maybe some sparkling day this copy wil be the slowest thing in our stack.
+	// It's not even on the radar now.
+	rbuf := sliceOf(r.buf, n)
+	copy(buf, rbuf)
+	// Queue up a new request.
+	if err := u.submitRecvRequest(int(idx)); err != nil {
+		// Aggressively return this error.
+		// The error will bubble up and cause the entire conn to be closed down,
+		// so it doesn't matter that we lost a packet here.
+		return 0, netaddr.IPPort{}, err
+	}
+	return n, ipp, nil
+}
+
+func (c *UDPConn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
+	n, ipp, err := c.ReadFromNetaddr(p)
+	if err != nil {
+		return 0, nil, err
+	}
+	return n, ipp.UDPAddr(), err
+}
+
+func (u *UDPConn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
+	// The docs for the u.refcount field document this prologue.
+	u.refcount.Add(1)
+	defer u.refcount.Add(-1)
+	if u.closed.Get() {
+		return 0, net.ErrClosed
+	}
+
+	udpAddr, ok := addr.(*net.UDPAddr)
+	if !ok {
+		return 0, fmt.Errorf("cannot WriteTo net.Addr of type %T", addr)
+	}
+
+	// Get a req, blocking as needed.
+	r, err := u.sendRing.getReq()
+	if err != nil {
+		return 0, err
+	}
+	// Do the write.
+	rbuf := sliceOf(r.buf, len(p))
+	copy(rbuf, p)
+
+	if u.is4 {
+		dst := (*[4]byte)((unsafe.Pointer)(&r.sa.sin_addr.s_addr))
+		src := (*[4]byte)((unsafe.Pointer)(&udpAddr.IP[0]))
+		*dst = *src
+		r.sa.sin_port = C.uint16_t(endian.Hton16(uint16(udpAddr.Port)))
+		r.sa.sin_family = C.AF_INET
+	} else {
+		dst := (*[16]byte)((unsafe.Pointer)(&r.sa6.sin6_addr))
+		src := (*[16]byte)((unsafe.Pointer)(&udpAddr.IP[0]))
+		*dst = *src
+		r.sa6.sin6_port = C.uint16_t(endian.Hton16(uint16(udpAddr.Port)))
+		r.sa6.sin6_family = C.AF_INET6
+	}
+	C.submit_sendmsg_request(u.sendRing.ring, r, C.int(len(p)))
+	// Get an extra buffer, if available.
+	u.sendRing.prefetch()
+	return len(p), nil
+}
+
+func (u *UDPConn) Close() error {
+	u.close.Do(func() {
+		// Announce to readers and writers that we are closing down.
+		// Busy loop until all reads and writes are unblocked.
+		// See the docs for u.refcount.
+		u.closed.Set(true)
+		for {
+			// Request that the kernel cancel all submitted reads. (Writes don't block indefinitely.)
+			for idx := range u.recvReqs {
+				if atomic.LoadInt32(u.recvReqInKernel(idx)) != 0 {
+					C.submit_cancel_request(u.recvRing, C.size_t(idx))
+				}
+			}
+			if u.refcount.Get() == 0 {
+				break
+			}
+			time.Sleep(time.Millisecond)
+		}
+		// Do the rest of the shutdown.
+		u.doShutdown()
+	})
+	return nil
+}
+
+func (u *UDPConn) doShutdown() {
+	for _, fn := range u.shutdown {
+		fn()
+	}
+}
+
+// Ensure that UDPConn implements net.PacketConn.
+var _ net.PacketConn = (*UDPConn)(nil)
+
+func (c *UDPConn) LocalAddr() net.Addr                { return c.local }
+func (c *UDPConn) SetDeadline(t time.Time) error      { panic("not implemented") }
+func (c *UDPConn) SetReadDeadline(t time.Time) error  { panic("not implemented") }
+func (c *UDPConn) SetWriteDeadline(t time.Time) error { panic("not implemented") }

net/uring/udp_test_linux.go

@@ -0,0 +1,45 @@
+package uring
+
+import (
+	"net"
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+)
+
+func TestUDPSendRecv(t *testing.T) {
+	if !Available() {
+		t.Skip("io_uring not available")
+	}
+	c := qt.New(t)
+
+	listen, err := net.ListenUDP("udp4", &net.UDPAddr{Port: 9999})
+	t.Cleanup(func() { listen.Close() })
+	c.Assert(err, qt.IsNil)
+
+	conn, err := NewUDPConn(listen)
+	t.Cleanup(func() { conn.Close() })
+	if err != nil {
+		t.Skipf("io_uring not available: %v", err)
+	}
+	addr := listen.LocalAddr()
+	sendBuf := make([]byte, 200)
+	for i := range sendBuf {
+		sendBuf[i] = byte(i)
+	}
+	recvBuf := make([]byte, 200)
+
+	// Write one direction.
+	_, err = conn.WriteTo(sendBuf, addr)
+	c.Assert(err, qt.IsNil)
+	n, ipp, err := conn.ReadFromNetaddr(recvBuf)
+	c.Assert(err, qt.IsNil)
+	c.Assert(recvBuf[:n], qt.DeepEquals, sendBuf)
+
+	// Write the other direction, to check that ipp is correct.
+	_, err = conn.WriteTo(sendBuf, ipp.UDPAddr())
+	c.Assert(err, qt.IsNil)
+	n, _, err = conn.ReadFromNetaddr(recvBuf)
+	c.Assert(err, qt.IsNil)
+	c.Assert(recvBuf[:n], qt.DeepEquals, sendBuf)
+}

safesocket/safesocket_darwin.go

@@ -53,16 +53,15 @@ func localTCPPortAndTokenDarwin() (port int, token string, err error) {
 	// The current process is running outside the sandbox, so use
 	// lsof to find the IPNExtension:
 
-	cmd := exec.Command("lsof",
+	out, err := exec.Command("lsof",
 		"-n",                             // numeric sockets; don't do DNS lookups, etc
 		"-a",                             // logical AND remaining options
 		fmt.Sprintf("-u%d", os.Getuid()), // process of same user only
 		"-c", "IPNExtension",             // starting with IPNExtension
 		"-F", // machine-readable output
-	)
-	out, err := cmd.Output()
+	).Output()
 	if err != nil {
-		return 0, "", fmt.Errorf("failed to run '%s' looking for IPNExtension: %w", cmd, err)
+		return 0, "", fmt.Errorf("failed to run lsof looking for IPNExtension: %w", err)
 	}
 	bs := bufio.NewScanner(bytes.NewReader(out))
 	subStr := []byte(".tailscale.ipn.macos/sameuserproof-")

safesocket/unixsocket.go

@@ -28,15 +28,16 @@ func connect(path string, port uint16) (net.Conn, error) {
 	pipe, err := net.Dial("unix", path)
 	if err != nil {
 		if runtime.GOOS == "darwin" {
-			extConn, extErr := connectMacOSAppSandbox()
-			if extErr != nil {
-				return nil, fmt.Errorf("safesocket: failed to connect to %v: %v; failed to connect to Tailscale IPNExtension: %v", path, err, extErr)
+			extConn, err := connectMacOSAppSandbox()
+			if err != nil {
+				log.Printf("safesocket: failed to connect to Tailscale IPNExtension: %v", err)
+			} else {
+				return extConn, nil
 			}
-			return extConn, nil
 		}
 		return nil, err
 	}
-	return pipe, nil
+	return pipe, err
 }
 
 // TODO(apenwarr): handle magic cookie auth

scripts/check_license_headers.sh

@@ -38,6 +38,9 @@ for file in $(find $1 -name '*.go' -not -path '*/.git/*'); do
         $1/wgengine/router/ifconfig_windows.go)
             # WireGuard copyright.
         ;;
+		*_string.go)
+			# Generated file from go:generate stringer
+		;;
         *)
             header="$(head -3 $file)"
             if ! check_file "$header"; then

syncs/syncs.go

@@ -79,16 +79,6 @@ func (b *AtomicBool) Set(v bool) {
 	atomic.StoreInt32((*int32)(b), n)
 }
 
-// Swap sets b to v and reports whether it changed.
-func (b *AtomicBool) Swap(v bool) (changed bool) {
-	var n int32
-	if v {
-		n = 1
-	}
-	old := atomic.SwapInt32((*int32)(b), n)
-	return old != n
-}
-
 func (b *AtomicBool) Get() bool {
 	return atomic.LoadInt32((*int32)(b)) != 0
 }
@@ -104,6 +94,21 @@ func (b *AtomicUint32) Get() uint32 {
 	return atomic.LoadUint32((*uint32)(b))
 }
 
+// AtomicInt32 is an atomic int32.
+type AtomicInt32 int32
+
+func (b *AtomicInt32) Set(v int32) {
+	atomic.StoreInt32((*int32)(b), v)
+}
+
+func (b *AtomicInt32) Get() int32 {
+	return atomic.LoadInt32((*int32)(b))
+}
+
+func (b *AtomicInt32) Add(v int32) {
+	atomic.AddInt32((*int32)(b), v)
+}
+
 // Semaphore is a counting semaphore.
 //
 // Use NewSemaphore to create one.

tailcfg/tailcfg.go

@@ -164,12 +164,6 @@ type Node struct {
 	Hostinfo   Hostinfo
 	Created    time.Time
 
-	// PrimaryRoutes are the routes from AllowedIPs that this node
-	// is currently the primary subnet router for, as determined
-	// by the control plane. It does not include the self address
-	// values from Addresses that are in AllowedIPs.
-	PrimaryRoutes []netaddr.IPPrefix `json:",omitempty"`
-
 	// LastSeen is when the node was last online. It is not
 	// updated when Online is true. It is nil if the current
 	// node doesn't have permission to know, or the node
@@ -1066,13 +1060,6 @@ type Debug struct {
 	// :0 to get a random local port, ignoring any configured
 	// fixed port.
 	RandomizeClientPort bool `json:",omitempty"`
-
-	/// DisableUPnP is whether the client will attempt to perform a UPnP portmapping.
-	// By default, we want to enable it to see if it works on more clients.
-	//
-	// If UPnP catastrophically fails for people, this should be set to True to kill
-	// new attempts at UPnP connections.
-	DisableUPnP opt.Bool `json:",omitempty"`
 }
 
 func (k MachineKey) String() string                   { return fmt.Sprintf("mkey:%x", k[:]) }
@@ -1148,7 +1135,6 @@ func (n *Node) Equal(n2 *Node) bool {
 		eqBoolPtr(n.Online, n2.Online) &&
 		eqCIDRs(n.Addresses, n2.Addresses) &&
 		eqCIDRs(n.AllowedIPs, n2.AllowedIPs) &&
-		eqCIDRs(n.PrimaryRoutes, n2.PrimaryRoutes) &&
 		eqStrings(n.Endpoints, n2.Endpoints) &&
 		n.DERP == n2.DERP &&
 		n.Hostinfo.Equal(&n2.Hostinfo) &&

tailcfg/tailcfg_clone.go

@@ -49,7 +49,6 @@ func (src *Node) Clone() *Node {
 	dst.AllowedIPs = append(src.AllowedIPs[:0:0], src.AllowedIPs...)
 	dst.Endpoints = append(src.Endpoints[:0:0], src.Endpoints...)
 	dst.Hostinfo = *src.Hostinfo.Clone()
-	dst.PrimaryRoutes = append(src.PrimaryRoutes[:0:0], src.PrimaryRoutes...)
 	if dst.LastSeen != nil {
 		dst.LastSeen = new(time.Time)
 		*dst.LastSeen = *src.LastSeen
@@ -80,7 +79,6 @@ var _NodeNeedsRegeneration = Node(struct {
 	DERP                    string
 	Hostinfo                Hostinfo
 	Created                 time.Time
-	PrimaryRoutes           []netaddr.IPPrefix
 	LastSeen                *time.Time
 	Online                  *bool
 	KeepAlive               bool

tailcfg/tailcfg_test.go

@@ -194,8 +194,7 @@ func TestNodeEqual(t *testing.T) {
 		"ID", "StableID", "Name", "User", "Sharer",
 		"Key", "KeyExpiry", "Machine", "DiscoKey",
 		"Addresses", "AllowedIPs", "Endpoints", "DERP", "Hostinfo",
-		"Created", "PrimaryRoutes",
-		"LastSeen", "Online", "KeepAlive", "MachineAuthorized",
+		"Created", "LastSeen", "Online", "KeepAlive", "MachineAuthorized",
 		"Capabilities",
 		"ComputedName", "computedHostIfDifferent", "ComputedNameWithHost",
 	}

tempfork/wireguard-windows/firewall/zsyscall_windows.go

@@ -1,3 +1,5 @@
+// +build windows
+
 // Code generated by 'go generate'; DO NOT EDIT.
 
 package firewall

tstest/integration/gen_deps.go

@@ -12,25 +12,16 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
-	"os"
 	"os/exec"
 )
 
 func main() {
-	for _, goos := range []string{"windows", "linux", "darwin", "freebsd", "openbsd"} {
-		generate(goos)
-	}
-}
-
-func generate(goos string) {
 	var x struct {
 		Imports []string
 	}
-	cmd := exec.Command("go", "list", "-json", "tailscale.com/cmd/tailscaled")
-	cmd.Env = append(os.Environ(), "GOOS="+goos, "GOARCH=amd64")
-	j, err := cmd.Output()
+	j, err := exec.Command("go", "list", "-json", "tailscale.com/cmd/tailscaled").Output()
 	if err != nil {
-		log.Fatalf("GOOS=%s GOARCH=amd64 %s: %v", goos, cmd, err)
+		log.Fatal(err)
 	}
 	if err := json.Unmarshal(j, &x); err != nil {
 		log.Fatal(err)
@@ -55,8 +46,7 @@ import (
 	}
 	fmt.Fprintf(&out, ")\n")
 
-	filename := fmt.Sprintf("tailscaled_deps_test_%s.go", goos)
-	err = ioutil.WriteFile(filename, out.Bytes(), 0644)
+	err = ioutil.WriteFile("tailscaled_deps_test.go", out.Bytes(), 0644)
 	if err != nil {
 		log.Fatal(err)
 	}

tstest/integration/integration.go

@@ -205,13 +205,6 @@ func (lc *LogCatcher) logsString() string {
 	return lc.buf.String()
 }
 
-// Reset clears the buffered logs from memory.
-func (lc *LogCatcher) Reset() {
-	lc.mu.Lock()
-	defer lc.mu.Unlock()
-	lc.buf.Reset()
-}
-
 func (lc *LogCatcher) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	var body io.Reader = r.Body
 	if r.Header.Get("Content-Encoding") == "zstd" {

tstest/integration/integration_test.go

@@ -42,14 +42,11 @@ import (
 
 var (
 	verboseTailscaled = flag.Bool("verbose-tailscaled", false, "verbose tailscaled logging")
-	verboseTailscale  = flag.Bool("verbose-tailscale", false, "verbose tailscale CLI logging")
 )
 
 var mainError atomic.Value // of error
 
 func TestMain(m *testing.M) {
-	// Have to disable UPnP which hits the network, otherwise it fails due to HTTP proxy.
-	os.Setenv("TS_DISABLE_UPNP", "true")
 	flag.Parse()
 	v := m.Run()
 	if v != 0 {
@@ -73,9 +70,29 @@ func TestOneNodeUp_NoAuth(t *testing.T) {
 
 	d1 := n1.StartDaemon(t)
 	defer d1.Kill()
-	n1.AwaitResponding(t)
+
+	n1.AwaitListening(t)
+
+	st := n1.MustStatus(t)
+	t.Logf("Status: %s", st.BackendState)
+
+	if err := tstest.WaitFor(20*time.Second, func() error {
+		const sub = `Program starting: `
+		if !env.LogCatcher.logsContains(mem.S(sub)) {
+			return fmt.Errorf("log catcher didn't see %#q; got %s", sub, env.LogCatcher.logsString())
+		}
+		return nil
+	}); err != nil {
+		t.Error(err)
+	}
+
 	n1.MustUp()
 
+	if d, _ := time.ParseDuration(os.Getenv("TS_POST_UP_SLEEP")); d > 0 {
+		t.Logf("Sleeping for %v to give 'up' time to misbehave (https://github.com/tailscale/tailscale/issues/1840) ...", d)
+		time.Sleep(d)
+	}
+
 	t.Logf("Got IP: %v", n1.AwaitIP(t))
 	n1.AwaitRunning(t)
 
@@ -84,40 +101,6 @@ func TestOneNodeUp_NoAuth(t *testing.T) {
 	t.Logf("number of HTTP logcatcher requests: %v", env.LogCatcher.numRequests())
 }
 
-func TestCollectPanic(t *testing.T) {
-	t.Parallel()
-	bins := BuildTestBinaries(t)
-
-	env := newTestEnv(t, bins)
-	defer env.Close()
-
-	n := newTestNode(t, env)
-
-	cmd := exec.Command(n.env.Binaries.Daemon, "--cleanup")
-	cmd.Env = append(os.Environ(),
-		"TS_PLEASE_PANIC=1",
-		"TS_LOG_TARGET="+n.env.LogCatcherServer.URL,
-	)
-	got, _ := cmd.CombinedOutput() // we expect it to fail, ignore err
-	t.Logf("initial run: %s", got)
-
-	// Now we run it again, and on start, it will upload the logs to logcatcher.
-	cmd = exec.Command(n.env.Binaries.Daemon, "--cleanup")
-	cmd.Env = append(os.Environ(), "TS_LOG_TARGET="+n.env.LogCatcherServer.URL)
-	if out, err := cmd.CombinedOutput(); err != nil {
-		t.Fatalf("cleanup failed: %v: %q", err, out)
-	}
-	if err := tstest.WaitFor(20*time.Second, func() error {
-		const sub = `panic`
-		if !n.env.LogCatcher.logsContains(mem.S(sub)) {
-			return fmt.Errorf("log catcher didn't see %#q; got %s", sub, n.env.LogCatcher.logsString())
-		}
-		return nil
-	}); err != nil {
-		t.Fatal(err)
-	}
-}
-
 // test Issue 2321: Start with UpdatePrefs should save prefs to disk
 func TestStateSavedOnStart(t *testing.T) {
 	t.Parallel()
@@ -130,7 +113,22 @@ func TestStateSavedOnStart(t *testing.T) {
 
 	d1 := n1.StartDaemon(t)
 	defer d1.Kill()
-	n1.AwaitResponding(t)
+
+	n1.AwaitListening(t)
+
+	st := n1.MustStatus(t)
+	t.Logf("Status: %s", st.BackendState)
+
+	if err := tstest.WaitFor(20*time.Second, func() error {
+		const sub = `Program starting: `
+		if !env.LogCatcher.logsContains(mem.S(sub)) {
+			return fmt.Errorf("log catcher didn't see %#q; got %s", sub, env.LogCatcher.logsString())
+		}
+		return nil
+	}); err != nil {
+		t.Error(err)
+	}
+
 	n1.MustUp()
 
 	t.Logf("Got IP: %v", n1.AwaitIP(t))
@@ -346,76 +344,6 @@ func TestAddPingRequest(t *testing.T) {
 	t.Error("all ping attempts failed")
 }
 
-// Issue 2434: when "down" (WantRunning false), tailscaled shouldn't
-// be connected to control.
-func TestNoControlConnWhenDown(t *testing.T) {
-	t.Parallel()
-	bins := BuildTestBinaries(t)
-
-	env := newTestEnv(t, bins)
-	defer env.Close()
-
-	n1 := newTestNode(t, env)
-
-	d1 := n1.StartDaemon(t)
-	defer d1.Kill()
-	n1.AwaitResponding(t)
-
-	// Come up the first time.
-	n1.MustUp()
-	ip1 := n1.AwaitIP(t)
-	n1.AwaitRunning(t)
-
-	// Then bring it down and stop the daemon.
-	n1.MustDown()
-	d1.MustCleanShutdown(t)
-
-	env.LogCatcher.Reset()
-	d2 := n1.StartDaemon(t)
-	defer d2.Kill()
-	n1.AwaitResponding(t)
-
-	st := n1.MustStatus(t)
-	if got, want := st.BackendState, "Stopped"; got != want {
-		t.Fatalf("after restart, state = %q; want %q", got, want)
-	}
-
-	ip2 := n1.AwaitIP(t)
-	if ip1 != ip2 {
-		t.Errorf("IPs different: %q vs %q", ip1, ip2)
-	}
-
-	// The real test: verify our daemon doesn't have an HTTP request open.:
-	if n := env.Control.InServeMap(); n != 0 {
-		t.Errorf("in serve map = %d; want 0", n)
-	}
-
-	d2.MustCleanShutdown(t)
-}
-
-// Issue 2137: make sure Windows tailscaled works with the CLI alone,
-// without the GUI to kick off a Start.
-func TestOneNodeUpWindowsStyle(t *testing.T) {
-	t.Parallel()
-	bins := BuildTestBinaries(t)
-
-	env := newTestEnv(t, bins)
-	defer env.Close()
-
-	n1 := newTestNode(t, env)
-	n1.upFlagGOOS = "windows"
-
-	d1 := n1.StartDaemonAsIPNGOOS(t, "windows")
-	defer d1.Kill()
-	n1.AwaitResponding(t)
-	n1.MustUp("--unattended")
-
-	t.Logf("Got IP: %v", n1.AwaitIP(t))
-	n1.AwaitRunning(t)
-
-	d1.MustCleanShutdown(t)
-}
-
 // testEnv contains the test environment (set of servers) used by one
 // or more nodes.
 type testEnv struct {
@@ -492,10 +420,9 @@ func (e *testEnv) Close() error {
 type testNode struct {
 	env *testEnv
 
-	dir        string // temp dir for sock & state
-	sockFile   string
-	stateFile  string
-	upFlagGOOS string // if non-empty, sets TS_DEBUG_UP_FLAG_GOOS for cmd/tailscale CLI
+	dir       string // temp dir for sock & state
+	sockFile  string
+	stateFile string
 
 	mu        sync.Mutex
 	onLogLine []func([]byte)
@@ -505,14 +432,10 @@ type testNode struct {
 // The node is not started automatically.
 func newTestNode(t *testing.T, env *testEnv) *testNode {
 	dir := t.TempDir()
-	sockFile := filepath.Join(dir, "tailscale.sock")
-	if len(sockFile) >= 104 {
-		t.Fatalf("sockFile path %q (len %v) is too long, must be < 104", sockFile, len(sockFile))
-	}
 	return &testNode{
 		env:       env,
 		dir:       dir,
-		sockFile:  sockFile,
+		sockFile:  filepath.Join(dir, "tailscale.sock"),
 		stateFile: filepath.Join(dir, "tailscale.state"),
 	}
 }
@@ -537,26 +460,6 @@ func (n *testNode) diskPrefs(t testing.TB) *ipn.Prefs {
 	return p
 }
 
-// AwaitResponding waits for n's tailscaled to be up enough to be
-// responding, but doesn't wait for any particular state.
-func (n *testNode) AwaitResponding(t testing.TB) {
-	t.Helper()
-	n.AwaitListening(t)
-
-	st := n.MustStatus(t)
-	t.Logf("Status: %s", st.BackendState)
-
-	if err := tstest.WaitFor(20*time.Second, func() error {
-		const sub = `Program starting: `
-		if !n.env.LogCatcher.logsContains(mem.S(sub)) {
-			return fmt.Errorf("log catcher didn't see %#q; got %s", sub, n.env.LogCatcher.logsString())
-		}
-		return nil
-	}); err != nil {
-		t.Fatal(err)
-	}
-}
-
 // addLogLineHook registers a hook f to be called on each tailscaled
 // log line output.
 func (n *testNode) addLogLineHook(f func([]byte)) {
@@ -658,10 +561,6 @@ func (d *Daemon) MustCleanShutdown(t testing.TB) {
 // StartDaemon starts the node's tailscaled, failing if it fails to
 // start.
 func (n *testNode) StartDaemon(t testing.TB) *Daemon {
-	return n.StartDaemonAsIPNGOOS(t, runtime.GOOS)
-}
-
-func (n *testNode) StartDaemonAsIPNGOOS(t testing.TB, ipnGOOS string) *Daemon {
 	cmd := exec.Command(n.env.Binaries.Daemon,
 		"--tun=userspace-networking",
 		"--state="+n.stateFile,
@@ -672,8 +571,6 @@ func (n *testNode) StartDaemonAsIPNGOOS(t testing.TB, ipnGOOS string) *Daemon {
 		"TS_LOG_TARGET="+n.env.LogCatcherServer.URL,
 		"HTTP_PROXY="+n.env.TrafficTrapServer.URL,
 		"HTTPS_PROXY="+n.env.TrafficTrapServer.URL,
-		"TS_DEBUG_TAILSCALED_IPN_GOOS="+ipnGOOS,
-		"TS_LOGS_DIR="+t.TempDir(),
 	)
 	cmd.Stderr = &nodeOutputParser{n: n}
 	if *verboseTailscaled {
@@ -688,15 +585,10 @@ func (n *testNode) StartDaemonAsIPNGOOS(t testing.TB, ipnGOOS string) *Daemon {
 	}
 }
 
-func (n *testNode) MustUp(extraArgs ...string) {
+func (n *testNode) MustUp() {
 	t := n.env.t
-	args := []string{
-		"up",
-		"--login-server=" + n.env.ControlServer.URL,
-	}
-	args = append(args, extraArgs...)
-	t.Logf("Running %v ...", args)
-	if err := n.Tailscale(args...).Run(); err != nil {
+	t.Logf("Running up --login-server=%s ...", n.env.ControlServer.URL)
+	if err := n.Tailscale("up", "--login-server="+n.env.ControlServer.URL).Run(); err != nil {
 		t.Fatalf("up: %v", err)
 	}
 }
@@ -728,10 +620,7 @@ func (n *testNode) AwaitIPs(t testing.TB) []netaddr.IP {
 	t.Helper()
 	var addrs []netaddr.IP
 	if err := tstest.WaitFor(20*time.Second, func() error {
-		cmd := n.Tailscale("ip")
-		cmd.Stdout = nil // in case --verbose-tailscale was set
-		cmd.Stderr = nil // in case --verbose-tailscale was set
-		out, err := cmd.Output()
+		out, err := n.Tailscale("ip").Output()
 		if err != nil {
 			return err
 		}
@@ -763,7 +652,6 @@ func (n *testNode) AwaitIP(t testing.TB) netaddr.IP {
 	return ips[0]
 }
 
-// AwaitRunning waits for n to reach the IPN state "Running".
 func (n *testNode) AwaitRunning(t testing.TB) {
 	t.Helper()
 	if err := tstest.WaitFor(20*time.Second, func() error {
@@ -786,22 +674,11 @@ func (n *testNode) Tailscale(arg ...string) *exec.Cmd {
 	cmd := exec.Command(n.env.Binaries.CLI, "--socket="+n.sockFile)
 	cmd.Args = append(cmd.Args, arg...)
 	cmd.Dir = n.dir
-	cmd.Env = append(os.Environ(),
-		"TS_DEBUG_UP_FLAG_GOOS="+n.upFlagGOOS,
-		"TS_LOGS_DIR="+n.env.t.TempDir(),
-	)
-	if *verboseTailscale {
-		cmd.Stdout = os.Stdout
-		cmd.Stderr = os.Stderr
-	}
 	return cmd
 }
 
 func (n *testNode) Status() (*ipnstate.Status, error) {
-	cmd := n.Tailscale("status", "--json")
-	cmd.Stdout = nil // in case --verbose-tailscale was set
-	cmd.Stderr = nil // in case --verbose-tailscale was set
-	out, err := cmd.CombinedOutput()
+	out, err := n.Tailscale("status", "--json").CombinedOutput()
 	if err != nil {
 		return nil, fmt.Errorf("running tailscale status: %v, %s", err, out)
 	}

tstest/integration/tailscaled_deps_test.go

@@ -39,7 +39,6 @@ import (
 	_ "tailscale.com/logpolicy"
 	_ "tailscale.com/net/dns"
 	_ "tailscale.com/net/interfaces"
-	_ "tailscale.com/net/portmapper"
 	_ "tailscale.com/net/socks5/tssocks"
 	_ "tailscale.com/net/tshttpproxy"
 	_ "tailscale.com/net/tstun"

tstest/integration/tailscaled_deps_test_darwin.go

@@ -1,61 +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.
-
-// Code generated by gen_deps.go; DO NOT EDIT.
-
-package integration
-
-import (
-	// And depend on a bunch of tailscaled innards, for Go's test caching.
-	// Otherwise cmd/go never sees that we depend on these packages'
-	// transitive deps when we run "go install tailscaled" in a child
-	// process and can cache a prior success when a dependency changes.
-	_ "context"
-	_ "crypto/tls"
-	_ "encoding/json"
-	_ "errors"
-	_ "flag"
-	_ "fmt"
-	_ "github.com/go-multierror/multierror"
-	_ "io"
-	_ "io/ioutil"
-	_ "log"
-	_ "net"
-	_ "net/http"
-	_ "net/http/httptrace"
-	_ "net/http/pprof"
-	_ "net/url"
-	_ "os"
-	_ "os/exec"
-	_ "os/signal"
-	_ "path/filepath"
-	_ "runtime"
-	_ "runtime/debug"
-	_ "strconv"
-	_ "strings"
-	_ "syscall"
-	_ "tailscale.com/derp/derphttp"
-	_ "tailscale.com/ipn"
-	_ "tailscale.com/ipn/ipnserver"
-	_ "tailscale.com/logpolicy"
-	_ "tailscale.com/net/dns"
-	_ "tailscale.com/net/interfaces"
-	_ "tailscale.com/net/portmapper"
-	_ "tailscale.com/net/socks5/tssocks"
-	_ "tailscale.com/net/tshttpproxy"
-	_ "tailscale.com/net/tstun"
-	_ "tailscale.com/paths"
-	_ "tailscale.com/tailcfg"
-	_ "tailscale.com/types/flagtype"
-	_ "tailscale.com/types/key"
-	_ "tailscale.com/types/logger"
-	_ "tailscale.com/util/osshare"
-	_ "tailscale.com/version"
-	_ "tailscale.com/version/distro"
-	_ "tailscale.com/wgengine"
-	_ "tailscale.com/wgengine/monitor"
-	_ "tailscale.com/wgengine/netstack"
-	_ "tailscale.com/wgengine/router"
-	_ "time"
-)

tstest/integration/tailscaled_deps_test_freebsd.go

@@ -1,59 +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.
-
-// Code generated by gen_deps.go; DO NOT EDIT.
-
-package integration
-
-import (
-	// And depend on a bunch of tailscaled innards, for Go's test caching.
-	// Otherwise cmd/go never sees that we depend on these packages'
-	// transitive deps when we run "go install tailscaled" in a child
-	// process and can cache a prior success when a dependency changes.
-	_ "context"
-	_ "crypto/tls"
-	_ "encoding/json"
-	_ "errors"
-	_ "flag"
-	_ "fmt"
-	_ "github.com/go-multierror/multierror"
-	_ "io"
-	_ "io/ioutil"
-	_ "log"
-	_ "net"
-	_ "net/http"
-	_ "net/http/httptrace"
-	_ "net/http/pprof"
-	_ "net/url"
-	_ "os"
-	_ "os/signal"
-	_ "runtime"
-	_ "runtime/debug"
-	_ "strconv"
-	_ "strings"
-	_ "syscall"
-	_ "tailscale.com/derp/derphttp"
-	_ "tailscale.com/ipn"
-	_ "tailscale.com/ipn/ipnserver"
-	_ "tailscale.com/logpolicy"
-	_ "tailscale.com/net/dns"
-	_ "tailscale.com/net/interfaces"
-	_ "tailscale.com/net/portmapper"
-	_ "tailscale.com/net/socks5/tssocks"
-	_ "tailscale.com/net/tshttpproxy"
-	_ "tailscale.com/net/tstun"
-	_ "tailscale.com/paths"
-	_ "tailscale.com/tailcfg"
-	_ "tailscale.com/types/flagtype"
-	_ "tailscale.com/types/key"
-	_ "tailscale.com/types/logger"
-	_ "tailscale.com/util/osshare"
-	_ "tailscale.com/version"
-	_ "tailscale.com/version/distro"
-	_ "tailscale.com/wgengine"
-	_ "tailscale.com/wgengine/monitor"
-	_ "tailscale.com/wgengine/netstack"
-	_ "tailscale.com/wgengine/router"
-	_ "time"
-)

tstest/integration/tailscaled_deps_test_openbsd.go

@@ -1,59 +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.
-
-// Code generated by gen_deps.go; DO NOT EDIT.
-
-package integration
-
-import (
-	// And depend on a bunch of tailscaled innards, for Go's test caching.
-	// Otherwise cmd/go never sees that we depend on these packages'
-	// transitive deps when we run "go install tailscaled" in a child
-	// process and can cache a prior success when a dependency changes.
-	_ "context"
-	_ "crypto/tls"
-	_ "encoding/json"
-	_ "errors"
-	_ "flag"
-	_ "fmt"
-	_ "github.com/go-multierror/multierror"
-	_ "io"
-	_ "io/ioutil"
-	_ "log"
-	_ "net"
-	_ "net/http"
-	_ "net/http/httptrace"
-	_ "net/http/pprof"
-	_ "net/url"
-	_ "os"
-	_ "os/signal"
-	_ "runtime"
-	_ "runtime/debug"
-	_ "strconv"
-	_ "strings"
-	_ "syscall"
-	_ "tailscale.com/derp/derphttp"
-	_ "tailscale.com/ipn"
-	_ "tailscale.com/ipn/ipnserver"
-	_ "tailscale.com/logpolicy"
-	_ "tailscale.com/net/dns"
-	_ "tailscale.com/net/interfaces"
-	_ "tailscale.com/net/portmapper"
-	_ "tailscale.com/net/socks5/tssocks"
-	_ "tailscale.com/net/tshttpproxy"
-	_ "tailscale.com/net/tstun"
-	_ "tailscale.com/paths"
-	_ "tailscale.com/tailcfg"
-	_ "tailscale.com/types/flagtype"
-	_ "tailscale.com/types/key"
-	_ "tailscale.com/types/logger"
-	_ "tailscale.com/util/osshare"
-	_ "tailscale.com/version"
-	_ "tailscale.com/version/distro"
-	_ "tailscale.com/wgengine"
-	_ "tailscale.com/wgengine/monitor"
-	_ "tailscale.com/wgengine/netstack"
-	_ "tailscale.com/wgengine/router"
-	_ "time"
-)

tstest/integration/tailscaled_deps_test_windows.go

@@ -1,66 +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.
-
-// Code generated by gen_deps.go; DO NOT EDIT.
-
-package integration
-
-import (
-	// And depend on a bunch of tailscaled innards, for Go's test caching.
-	// Otherwise cmd/go never sees that we depend on these packages'
-	// transitive deps when we run "go install tailscaled" in a child
-	// process and can cache a prior success when a dependency changes.
-	_ "context"
-	_ "crypto/tls"
-	_ "encoding/json"
-	_ "errors"
-	_ "flag"
-	_ "fmt"
-	_ "github.com/go-multierror/multierror"
-	_ "golang.org/x/sys/windows"
-	_ "golang.org/x/sys/windows/svc"
-	_ "golang.org/x/sys/windows/svc/mgr"
-	_ "golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
-	_ "inet.af/netaddr"
-	_ "io"
-	_ "io/ioutil"
-	_ "log"
-	_ "net"
-	_ "net/http"
-	_ "net/http/httptrace"
-	_ "net/http/pprof"
-	_ "net/url"
-	_ "os"
-	_ "os/signal"
-	_ "runtime"
-	_ "runtime/debug"
-	_ "strconv"
-	_ "strings"
-	_ "syscall"
-	_ "tailscale.com/derp/derphttp"
-	_ "tailscale.com/ipn"
-	_ "tailscale.com/ipn/ipnserver"
-	_ "tailscale.com/logpolicy"
-	_ "tailscale.com/logtail/backoff"
-	_ "tailscale.com/net/dns"
-	_ "tailscale.com/net/interfaces"
-	_ "tailscale.com/net/portmapper"
-	_ "tailscale.com/net/socks5/tssocks"
-	_ "tailscale.com/net/tshttpproxy"
-	_ "tailscale.com/net/tstun"
-	_ "tailscale.com/paths"
-	_ "tailscale.com/tailcfg"
-	_ "tailscale.com/types/flagtype"
-	_ "tailscale.com/types/key"
-	_ "tailscale.com/types/logger"
-	_ "tailscale.com/util/osshare"
-	_ "tailscale.com/version"
-	_ "tailscale.com/version/distro"
-	_ "tailscale.com/wf"
-	_ "tailscale.com/wgengine"
-	_ "tailscale.com/wgengine/monitor"
-	_ "tailscale.com/wgengine/netstack"
-	_ "tailscale.com/wgengine/router"
-	_ "time"
-)

tstest/integration/testcontrol/testcontrol.go

@@ -51,7 +51,6 @@ type Server struct {
 	mux         *http.ServeMux
 
 	mu            sync.Mutex
-	inServeMap    int
 	cond          *sync.Cond // lazily initialized by condLocked
 	pubKey        wgkey.Key
 	privKey       wgkey.Private
@@ -510,22 +509,7 @@ func (s *Server) UpdateNode(n *tailcfg.Node) (peersToUpdate []tailcfg.NodeID) {
 	return peersToUpdate
 }
 
-func (s *Server) incrInServeMap(delta int) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	s.inServeMap += delta
-}
-
-// InServeMap returns the number of clients currently in a MapRequest HTTP handler.
-func (s *Server) InServeMap() int {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	return s.inServeMap
-}
-
 func (s *Server) serveMap(w http.ResponseWriter, r *http.Request, mkey tailcfg.MachineKey) {
-	s.incrInServeMap(1)
-	defer s.incrInServeMap(-1)
 	ctx := r.Context()
 
 	req := new(tailcfg.MapRequest)
@@ -652,9 +636,6 @@ func (s *Server) MapResponse(req *tailcfg.MapRequest) (res *tailcfg.MapResponse,
 		Domain:          string(user.Domain),
 		CollectServices: "true",
 		PacketFilter:    tailcfg.FilterAllowAll,
-		Debug: &tailcfg.Debug{
-			DisableUPnP: "true",
-		},
 	}
 	for _, p := range s.AllNodes() {
 		if p.StableID != node.StableID {