net/netmon: add netmon hook for os-derived network change notifications

Update tailscale/corp#20677

While hunting down DNS issues, it was observed that
on apple platforms, w attempt to rebind to interfaces before they're
completely configured by the system.

The AF_ROUTE messages aren't lying, they're just not
taking into account other setup that has to happen,
notably the system setting the interface nameservers.
When we react based on the route updates, it's often
too quickly.  This happens frequently on wakes-from-sleep.

This replumbs netmon so that (optionally) rather than reacting to every
system message by checking for interesting changes, we
use that only to update our state, and recheck for interesting
network changes when we get a poke from the upper layers
indicating that a network change has 'completed'.  Notably on
Apple, NWPathMonitor seems to call us back at the correct
time(s) to check for potentially interesting interface changes
that have been observed via AF_ROUTE and to react to them.

This seems to reduce thrashing during network
transitions, and avoids some of the bad states we were
previously ending up in.

This is entirely opt in during the construction of the netmon
and will have no effect until/unless a specific client chooses
to use it.

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>

.github/workflows/checklocks.yml

@@ -24,5 +24,11 @@ jobs:
         run: ./tool/go build -o /tmp/checklocks gvisor.dev/gvisor/tools/checklocks/cmd/checklocks
 
       - name: Run checklocks vet
-        # TODO: remove || true once we have applied checklocks annotations everywhere.
-        run: ./tool/go vet -vettool=/tmp/checklocks ./... || true
+        # TODO(#12625): add more packages as we add annotations
+        run: |-
+          ./tool/go vet -vettool=/tmp/checklocks \
+            ./envknob           \
+            ./ipn/store/mem     \
+            ./net/stun/stuntest \
+            ./net/wsconn        \
+            ./proxymap

.github/workflows/installer.yml

@@ -67,6 +67,11 @@ jobs:
       image: ${{ matrix.image }}
       options: --user root
     steps:
+    - name: install dependencies (pacman)
+      # Refresh the package databases to ensure that the tailscale package is
+      # defined.
+      run: pacman -Sy
+      if: contains(matrix.image, 'archlinux')
     - name: install dependencies (yum)
       # tar and gzip are needed by the actions/checkout below.
       run: yum install -y --allowerasing tar gzip ${{ matrix.deps }}

.gitignore

@@ -43,3 +43,9 @@ client/web/build/assets
 
 /gocross
 /dist
+
+# Ignore xcode userstate and workspace data
+*.xcuserstate
+*.xcworkspacedata
+/tstest/tailmac/bin
+/tstest/tailmac/build

Dockerfile

@@ -1,17 +1,13 @@
 # Copyright (c) Tailscale Inc & AUTHORS
 # SPDX-License-Identifier: BSD-3-Clause
 
-############################################################################
+# Note that this Dockerfile is currently NOT used to build any of the published
+# Tailscale container images and may have drifted from the image build mechanism
+# we use.
+# Tailscale images are currently built using https://github.com/tailscale/mkctr,
+# and the build script can be found in ./build_docker.sh.
 #
-# WARNING: Tailscale is not yet officially supported in container
-# environments, such as Docker and Kubernetes. Though it should work, we
-# don't regularly test it, and we know there are some feature limitations.
 #
-# See current bugs tagged "containers":
-#    https://github.com/tailscale/tailscale/labels/containers
-#
-############################################################################
-
 # This Dockerfile includes all the tailscale binaries.
 #
 # To build the Dockerfile:
@@ -46,7 +42,7 @@ RUN go install \
     gvisor.dev/gvisor/pkg/tcpip/stack \
     golang.org/x/crypto/ssh \
     golang.org/x/crypto/acme \
-    nhooyr.io/websocket \
+    github.com/coder/websocket \
     github.com/mdlayher/netlink
 
 COPY . .

Makefile

@@ -21,6 +21,7 @@ updatedeps: ## Update depaware deps
 		tailscale.com/cmd/tailscaled \
 		tailscale.com/cmd/tailscale \
 		tailscale.com/cmd/derper \
+		tailscale.com/cmd/k8s-operator \
 		tailscale.com/cmd/stund
 
 depaware: ## Run depaware checks
@@ -30,6 +31,7 @@ depaware: ## Run depaware checks
 		tailscale.com/cmd/tailscaled \
 		tailscale.com/cmd/tailscale \
 		tailscale.com/cmd/derper \
+		tailscale.com/cmd/k8s-operator \
 		tailscale.com/cmd/stund
 
 buildwindows: ## Build tailscale CLI for windows/amd64
@@ -115,7 +117,8 @@ sshintegrationtest: ## Run the SSH integration tests in various Docker container
 	echo "Testing on ubuntu:focal" && docker build --build-arg="BASE=ubuntu:focal" -t ssh-ubuntu-focal ssh/tailssh/testcontainers && \
 	echo "Testing on ubuntu:jammy" && docker build --build-arg="BASE=ubuntu:jammy" -t ssh-ubuntu-jammy ssh/tailssh/testcontainers && \
 	echo "Testing on ubuntu:mantic" && docker build --build-arg="BASE=ubuntu:mantic" -t ssh-ubuntu-mantic ssh/tailssh/testcontainers && \
-	echo "Testing on ubuntu:noble" && docker build --build-arg="BASE=ubuntu:noble" -t ssh-ubuntu-noble ssh/tailssh/testcontainers
+	echo "Testing on ubuntu:noble" && docker build --build-arg="BASE=ubuntu:noble" -t ssh-ubuntu-noble ssh/tailssh/testcontainers && \
+	echo "Testing on alpine:latest" && docker build --build-arg="BASE=alpine:latest" -t ssh-alpine-latest ssh/tailssh/testcontainers
 
 help: ## Show this help
 	@echo "\nSpecify a command. The choices are:\n"

VERSION.txt

@@ -1 +1 @@
-1.69.0
+1.73.0

api.md

@@ -1,3 +1,6 @@
+> [!IMPORTANT]
+> The Tailscale API documentation has moved to https://tailscale.com/api
+
 # Tailscale API
 
 The Tailscale API documentation is located in **[tailscale/publicapi](./publicapi/readme.md#tailscale-api)**.

appc/appconnector.go

@@ -11,6 +11,7 @@ package appc
 
 import (
 	"context"
+	"fmt"
 	"net/netip"
 	"slices"
 	"strings"
@@ -21,6 +22,7 @@ import (
 	"golang.org/x/net/dns/dnsmessage"
 	"tailscale.com/types/logger"
 	"tailscale.com/types/views"
+	"tailscale.com/util/clientmetric"
 	"tailscale.com/util/dnsname"
 	"tailscale.com/util/execqueue"
 	"tailscale.com/util/mak"
@@ -78,6 +80,42 @@ type RouteAdvertiser interface {
 	UnadvertiseRoute(...netip.Prefix) error
 }
 
+var (
+	metricStoreRoutesRateBuckets = []int64{1, 2, 3, 4, 5, 10, 100, 1000}
+	metricStoreRoutesNBuckets    = []int64{1, 2, 3, 4, 5, 10, 100, 1000, 10000}
+	metricStoreRoutesRate        []*clientmetric.Metric
+	metricStoreRoutesN           []*clientmetric.Metric
+)
+
+func initMetricStoreRoutes() {
+	for _, n := range metricStoreRoutesRateBuckets {
+		metricStoreRoutesRate = append(metricStoreRoutesRate, clientmetric.NewCounter(fmt.Sprintf("appc_store_routes_rate_%d", n)))
+	}
+	metricStoreRoutesRate = append(metricStoreRoutesRate, clientmetric.NewCounter("appc_store_routes_rate_over"))
+	for _, n := range metricStoreRoutesNBuckets {
+		metricStoreRoutesN = append(metricStoreRoutesN, clientmetric.NewCounter(fmt.Sprintf("appc_store_routes_n_routes_%d", n)))
+	}
+	metricStoreRoutesN = append(metricStoreRoutesN, clientmetric.NewCounter("appc_store_routes_n_routes_over"))
+}
+
+func recordMetric(val int64, buckets []int64, metrics []*clientmetric.Metric) {
+	if len(buckets) < 1 {
+		return
+	}
+	// finds the first bucket where val <=, or len(buckets) if none match
+	// for bucket values of 1, 10, 100; 0-1 goes to [0], 2-10 goes to [1], 11-100 goes to [2], 101+ goes to [3]
+	bucket, _ := slices.BinarySearch(buckets, val)
+	metrics[bucket].Add(1)
+}
+
+func metricStoreRoutes(rate, nRoutes int64) {
+	if len(metricStoreRoutesRate) == 0 {
+		initMetricStoreRoutes()
+	}
+	recordMetric(rate, metricStoreRoutesRateBuckets, metricStoreRoutesRate)
+	recordMetric(nRoutes, metricStoreRoutesNBuckets, metricStoreRoutesN)
+}
+
 // RouteInfo is a data structure used to persist the in memory state of an AppConnector
 // so that we can know, even after a restart, which routes came from ACLs and which were
 // learned from domains.
@@ -141,6 +179,7 @@ func NewAppConnector(logf logger.Logf, routeAdvertiser RouteAdvertiser, routeInf
 	}
 	ac.writeRateMinute = newRateLogger(time.Now, time.Minute, func(c int64, s time.Time, l int64) {
 		ac.logf("routeInfo write rate: %d in minute starting at %v (%d routes)", c, s, l)
+		metricStoreRoutes(c, l)
 	})
 	ac.writeRateDay = newRateLogger(time.Now, 24*time.Hour, func(c int64, s time.Time, l int64) {
 		ac.logf("routeInfo write rate: %d in 24 hours starting at %v (%d routes)", c, s, l)
@@ -442,8 +481,10 @@ func (e *AppConnector) ObserveDNSResponse(res []byte) {
 			}
 		}
 
-		e.logf("[v2] observed new routes for %s: %s", domain, toAdvertise)
-		e.scheduleAdvertisement(domain, toAdvertise...)
+		if len(toAdvertise) > 0 {
+			e.logf("[v2] observed new routes for %s: %s", domain, toAdvertise)
+			e.scheduleAdvertisement(domain, toAdvertise...)
+		}
 	}
 }
 

appc/appconnector_test.go

@@ -15,6 +15,7 @@ import (
 	"golang.org/x/net/dns/dnsmessage"
 	"tailscale.com/appc/appctest"
 	"tailscale.com/tstest"
+	"tailscale.com/util/clientmetric"
 	"tailscale.com/util/mak"
 	"tailscale.com/util/must"
 )
@@ -569,3 +570,35 @@ func TestRateLogger(t *testing.T) {
 		t.Fatalf("wasCalled: got false, want true")
 	}
 }
+
+func TestRouteStoreMetrics(t *testing.T) {
+	metricStoreRoutes(1, 1)
+	metricStoreRoutes(1, 1)         // the 1 buckets value should be 2
+	metricStoreRoutes(5, 5)         // the 5 buckets value should be 1
+	metricStoreRoutes(6, 6)         // the 10 buckets value should be 1
+	metricStoreRoutes(10001, 10001) // the over buckets value should be 1
+	wanted := map[string]int64{
+		"appc_store_routes_n_routes_1":    2,
+		"appc_store_routes_rate_1":        2,
+		"appc_store_routes_n_routes_5":    1,
+		"appc_store_routes_rate_5":        1,
+		"appc_store_routes_n_routes_10":   1,
+		"appc_store_routes_rate_10":       1,
+		"appc_store_routes_n_routes_over": 1,
+		"appc_store_routes_rate_over":     1,
+	}
+	for _, x := range clientmetric.Metrics() {
+		if x.Value() != wanted[x.Name()] {
+			t.Errorf("%s: want: %d, got: %d", x.Name(), wanted[x.Name()], x.Value())
+		}
+	}
+}
+
+func TestMetricBucketsAreSorted(t *testing.T) {
+	if !slices.IsSorted(metricStoreRoutesRateBuckets) {
+		t.Errorf("metricStoreRoutesRateBuckets must be in order")
+	}
+	if !slices.IsSorted(metricStoreRoutesNBuckets) {
+		t.Errorf("metricStoreRoutesNBuckets must be in order")
+	}
+}

appc/appctest/appctest.go

@@ -1,6 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// Package appctest contains code to help test App Connectors.
 package appctest
 
 import (

build_docker.sh

@@ -1,21 +1,11 @@
 #!/usr/bin/env sh
-
 #
-# Runs `go build` with flags configured for docker distribution. All
-# it does differently from `go build` is burn git commit and version
-# information into the binaries inside docker, so that we can track down user
-# issues.
-#
-############################################################################
-#
-# WARNING: Tailscale is not yet officially supported in container
-# environments, such as Docker and Kubernetes. Though it should work, we
-# don't regularly test it, and we know there are some feature limitations.
-#
-# See current bugs tagged "containers":
-#    https://github.com/tailscale/tailscale/labels/containers
-#
-############################################################################
+# This script builds Tailscale container images using
+# github.com/tailscale/mkctr.
+# By default the images will be tagged with the current version and git
+# hash of this repository as produced by ./cmd/mkversion.
+# This is the image build mechanim used to build the official Tailscale
+# container images.
 
 set -eu
 
@@ -49,7 +39,7 @@ case "$TARGET" in
         -X tailscale.com/version.gitCommitStamp=${VERSION_GIT_HASH}" \
       --base="${BASE}" \
       --tags="${TAGS}" \
-      --gotags="ts_kube" \
+      --gotags="ts_kube,ts_package_container" \
       --repos="${REPOS}" \
       --push="${PUSH}" \
       --target="${PLATFORM}" \

client/tailscale/acl.go

@@ -37,6 +37,16 @@ type ACLTest struct {
 	Allow []string `json:"allow,omitempty"` // old name for accept
 }
 
+// NodeAttrGrant defines additional string attributes that apply to specific devices.
+type NodeAttrGrant struct {
+	// Target specifies which nodes the attributes apply to. The nodes can be a
+	// tag (tag:server), user (alice@example.com), group (group:kids), or *.
+	Target []string `json:"target,omitempty"`
+
+	// Attr are the attributes to set on Target(s).
+	Attr []string `json:"attr,omitempty"`
+}
+
 // ACLDetails contains all the details for an ACL.
 type ACLDetails struct {
 	Tests     []ACLTest           `json:"tests,omitempty"`
@@ -44,6 +54,7 @@ type ACLDetails struct {
 	Groups    map[string][]string `json:"groups,omitempty"`
 	TagOwners map[string][]string `json:"tagowners,omitempty"`
 	Hosts     map[string]string   `json:"hosts,omitempty"`
+	NodeAttrs []NodeAttrGrant     `json:"nodeAttrs,omitempty"`
 }
 
 // ACL contains an ACLDetails and metadata.
@@ -150,7 +161,12 @@ func (c *Client) ACLHuJSON(ctx context.Context) (acl *ACLHuJSON, err error) {
 // ACLTestFailureSummary specifies the JSON format sent to the
 // JavaScript client to be rendered in the HTML.
 type ACLTestFailureSummary struct {
-	User     string   `json:"user,omitempty"`
+	// User is the source ("src") value of the ACL test that failed.
+	// The name "user" is a legacy holdover from the original naming and
+	// is kept for compatibility but it may also contain any value
+	// that's valid in a ACL test "src" field.
+	User string `json:"user,omitempty"`
+
 	Errors   []string `json:"errors,omitempty"`
 	Warnings []string `json:"warnings,omitempty"`
 }
@@ -270,6 +286,9 @@ type UserRuleMatch struct {
 	Users      []string `json:"users"`
 	Ports      []string `json:"ports"`
 	LineNumber int      `json:"lineNumber"`
+	// Via is the list of targets through which Users can access Ports.
+	// See https://tailscale.com/kb/1378/via for more information.
+	Via []string `json:"via,omitempty"`
 
 	// Postures is a list of posture policies that are
 	// associated with this match. The rules can be looked

client/tailscale/localclient.go

@@ -69,6 +69,14 @@ type LocalClient struct {
 	// connecting to the GUI client variants.
 	UseSocketOnly bool
 
+	// OmitAuth, if true, omits sending the local Tailscale daemon any
+	// authentication token that might be required by the platform.
+	//
+	// As of 2024-08-12, only macOS uses an authentication token. OmitAuth is
+	// meant for when Dial is set and the LocalAPI is being proxied to a
+	// different operating system, such as in integration tests.
+	OmitAuth bool
+
 	// tsClient does HTTP requests to the local Tailscale daemon.
 	// It's lazily initialized on first use.
 	tsClient     *http.Client
@@ -103,7 +111,7 @@ func (lc *LocalClient) defaultDialer(ctx context.Context, network, addr string)
 			return d.DialContext(ctx, "tcp", "127.0.0.1:"+strconv.Itoa(port))
 		}
 	}
-	return safesocket.Connect(lc.socket())
+	return safesocket.ConnectContext(ctx, lc.socket())
 }
 
 // DoLocalRequest makes an HTTP request to the local machine's Tailscale daemon.
@@ -124,8 +132,10 @@ func (lc *LocalClient) DoLocalRequest(req *http.Request) (*http.Response, error)
 			},
 		}
 	})
-	if _, token, err := safesocket.LocalTCPPortAndToken(); err == nil {
-		req.SetBasicAuth("", token)
+	if !lc.OmitAuth {
+		if _, token, err := safesocket.LocalTCPPortAndToken(); err == nil {
+			req.SetBasicAuth("", token)
+		}
 	}
 	return lc.tsClient.Do(req)
 }
@@ -933,7 +943,20 @@ func CertPair(ctx context.Context, domain string) (certPEM, keyPEM []byte, err e
 //
 // API maturity: this is considered a stable API.
 func (lc *LocalClient) CertPair(ctx context.Context, domain string) (certPEM, keyPEM []byte, err error) {
-	res, err := lc.send(ctx, "GET", "/localapi/v0/cert/"+domain+"?type=pair", 200, nil)
+	return lc.CertPairWithValidity(ctx, domain, 0)
+}
+
+// CertPairWithValidity returns a cert and private key for the provided DNS
+// domain.
+//
+// It returns a cached certificate from disk if it's still valid.
+// When minValidity is non-zero, the returned certificate will be valid for at
+// least the given duration, if permitted by the CA. If the certificate is
+// valid, but for less than minValidity, it will be synchronously renewed.
+//
+// API maturity: this is considered a stable API.
+func (lc *LocalClient) CertPairWithValidity(ctx context.Context, domain string, minValidity time.Duration) (certPEM, keyPEM []byte, err error) {
+	res, err := lc.send(ctx, "GET", fmt.Sprintf("/localapi/v0/cert/%s?type=pair&min_validity=%s", domain, minValidity), 200, nil)
 	if err != nil {
 		return nil, nil, err
 	}

client/web/package.json

@@ -3,7 +3,7 @@
   "version": "0.0.1",
   "license": "BSD-3-Clause",
   "engines": {
-    "node": "18.16.1",
+    "node": "18.20.4",
     "yarn": "1.22.19"
   },
   "type": "module",

clientupdate/clientupdate.go

@@ -248,6 +248,11 @@ func (up *Updater) getUpdateFunction() (fn updateFunction, canAutoUpdate bool) {
 // CanAutoUpdate reports whether auto-updating via the clientupdate package
 // is supported for the current os/distro.
 func CanAutoUpdate() bool {
+	if version.IsMacSysExt() {
+		// Macsys uses Sparkle for auto-updates, which doesn't have an update
+		// function in this package.
+		return true
+	}
 	_, canAutoUpdate := (&Updater{}).getUpdateFunction()
 	return canAutoUpdate
 }

cmd/cloner/cloner.go

@@ -78,7 +78,11 @@ func main() {
 		w("	return false")
 		w("}")
 	}
-	cloneOutput := pkg.Name + "_clone.go"
+	cloneOutput := pkg.Name + "_clone"
+	if *flagBuildTags == "test" {
+		cloneOutput += "_test"
+	}
+	cloneOutput += ".go"
 	if err := codegen.WritePackageFile("tailscale.com/cmd/cloner", pkg, cloneOutput, it, buf); err != nil {
 		log.Fatal(err)
 	}
@@ -91,16 +95,19 @@ func gen(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named) {
 	}
 
 	name := typ.Obj().Name()
+	typeParams := typ.Origin().TypeParams()
+	_, typeParamNames := codegen.FormatTypeParams(typeParams, it)
+	nameWithParams := name + typeParamNames
 	fmt.Fprintf(buf, "// Clone makes a deep copy of %s.\n", name)
 	fmt.Fprintf(buf, "// The result aliases no memory with the original.\n")
-	fmt.Fprintf(buf, "func (src *%s) Clone() *%s {\n", name, name)
+	fmt.Fprintf(buf, "func (src *%s) Clone() *%s {\n", nameWithParams, nameWithParams)
 	writef := func(format string, args ...any) {
 		fmt.Fprintf(buf, "\t"+format+"\n", args...)
 	}
 	writef("if src == nil {")
 	writef("\treturn nil")
 	writef("}")
-	writef("dst := new(%s)", name)
+	writef("dst := new(%s)", nameWithParams)
 	writef("*dst = *src")
 	for i := range t.NumFields() {
 		fname := t.Field(i).Name()
@@ -126,16 +133,23 @@ func gen(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named) {
 				writef("dst.%s = make([]%s, len(src.%s))", fname, n, fname)
 				writef("for i := range dst.%s {", fname)
 				if ptr, isPtr := ft.Elem().(*types.Pointer); isPtr {
-					if _, isBasic := ptr.Elem().Underlying().(*types.Basic); isBasic {
-						it.Import("tailscale.com/types/ptr")
-						writef("if src.%s[i] == nil { dst.%s[i] = nil } else {", fname, fname)
-						writef("\tdst.%s[i] = ptr.To(*src.%s[i])", fname, fname)
-						writef("}")
+					writef("if src.%s[i] == nil { dst.%s[i] = nil } else {", fname, fname)
+					if codegen.ContainsPointers(ptr.Elem()) {
+						if _, isIface := ptr.Elem().Underlying().(*types.Interface); isIface {
+							it.Import("tailscale.com/types/ptr")
+							writef("\tdst.%s[i] = ptr.To((*src.%s[i]).Clone())", fname, fname)
+						} else {
+							writef("\tdst.%s[i] = src.%s[i].Clone()", fname, fname)
+						}
 					} else {
-						writef("\tdst.%s[i] = src.%s[i].Clone()", fname, fname)
+						it.Import("tailscale.com/types/ptr")
+						writef("\tdst.%s[i] = ptr.To(*src.%s[i])", fname, fname)
 					}
+					writef("}")
 				} else if ft.Elem().String() == "encoding/json.RawMessage" {
 					writef("\tdst.%s[i] = append(src.%s[i][:0:0], src.%s[i]...)", fname, fname, fname)
+				} else if _, isIface := ft.Elem().Underlying().(*types.Interface); isIface {
+					writef("\tdst.%s[i] = src.%s[i].Clone()", fname, fname)
 				} else {
 					writef("\tdst.%s[i] = *src.%s[i].Clone()", fname, fname)
 				}
@@ -145,14 +159,19 @@ func gen(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named) {
 				writef("dst.%s = append(src.%s[:0:0], src.%s...)", fname, fname, fname)
 			}
 		case *types.Pointer:
-			if named, _ := ft.Elem().(*types.Named); named != nil && codegen.ContainsPointers(ft.Elem()) {
+			base := ft.Elem()
+			hasPtrs := codegen.ContainsPointers(base)
+			if named, _ := base.(*types.Named); named != nil && hasPtrs {
 				writef("dst.%s = src.%s.Clone()", fname, fname)
 				continue
 			}
 			it.Import("tailscale.com/types/ptr")
 			writef("if dst.%s != nil {", fname)
-			writef("\tdst.%s = ptr.To(*src.%s)", fname, fname)
-			if codegen.ContainsPointers(ft.Elem()) {
+			if _, isIface := base.Underlying().(*types.Interface); isIface && hasPtrs {
+				writef("\tdst.%s = ptr.To((*src.%s).Clone())", fname, fname)
+			} else if !hasPtrs {
+				writef("\tdst.%s = ptr.To(*src.%s)", fname, fname)
+			} else {
 				writef("\t" + `panic("TODO pointers in pointers")`)
 			}
 			writef("}")
@@ -172,18 +191,50 @@ func gen(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named) {
 				writef("if dst.%s != nil {", fname)
 				writef("\tdst.%s = map[%s]%s{}", fname, it.QualifiedName(ft.Key()), it.QualifiedName(elem))
 				writef("\tfor k, v := range src.%s {", fname)
-				switch elem.(type) {
+
+				switch elem := elem.Underlying().(type) {
 				case *types.Pointer:
-					writef("\t\tdst.%s[k] = v.Clone()", fname)
+					writef("\t\tif v == nil { dst.%s[k] = nil } else {", fname)
+					if base := elem.Elem().Underlying(); codegen.ContainsPointers(base) {
+						if _, isIface := base.(*types.Interface); isIface {
+							it.Import("tailscale.com/types/ptr")
+							writef("\t\t\tdst.%s[k] = ptr.To((*v).Clone())", fname)
+						} else {
+							writef("\t\t\tdst.%s[k] = v.Clone()", fname)
+						}
+					} else {
+						it.Import("tailscale.com/types/ptr")
+						writef("\t\t\tdst.%s[k] = ptr.To(*v)", fname)
+					}
+					writef("}")
+				case *types.Interface:
+					if cloneResultType := methodResultType(elem, "Clone"); cloneResultType != nil {
+						if _, isPtr := cloneResultType.(*types.Pointer); isPtr {
+							writef("\t\tdst.%s[k] = *(v.Clone())", fname)
+						} else {
+							writef("\t\tdst.%s[k] = v.Clone()", fname)
+						}
+					} else {
+						writef(`panic("%s (%v) does not have a Clone method")`, fname, elem)
+					}
 				default:
 					writef("\t\tdst.%s[k] = *(v.Clone())", fname)
 				}
+
 				writef("\t}")
 				writef("}")
 			} else {
 				it.Import("maps")
 				writef("\tdst.%s = maps.Clone(src.%s)", fname, fname)
 			}
+		case *types.Interface:
+			// If ft is an interface with a "Clone() ft" method, it can be used to clone the field.
+			// This includes scenarios where ft is a constrained type parameter.
+			if cloneResultType := methodResultType(ft, "Clone"); cloneResultType.Underlying() == ft {
+				writef("dst.%s = src.%s.Clone()", fname, fname)
+				continue
+			}
+			writef(`panic("%s (%v) does not have a compatible Clone method")`, fname, ft)
 		default:
 			writef(`panic("TODO: %s (%T)")`, fname, ft)
 		}
@@ -191,7 +242,7 @@ func gen(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named) {
 	writef("return dst")
 	fmt.Fprintf(buf, "}\n\n")
 
-	buf.Write(codegen.AssertStructUnchanged(t, name, "Clone", it))
+	buf.Write(codegen.AssertStructUnchanged(t, name, typeParams, "Clone", it))
 }
 
 // hasBasicUnderlying reports true when typ.Underlying() is a slice or a map.
@@ -203,3 +254,15 @@ func hasBasicUnderlying(typ types.Type) bool {
 		return false
 	}
 }
+
+func methodResultType(typ types.Type, method string) types.Type {
+	viewMethod := codegen.LookupMethod(typ, method)
+	if viewMethod == nil {
+		return nil
+	}
+	sig, ok := viewMethod.Type().(*types.Signature)
+	if !ok || sig.Results().Len() != 1 {
+		return nil
+	}
+	return sig.Results().At(0).Type()
+}

cmd/cloner/clonerex/clonerex.go

@@ -3,6 +3,7 @@
 
 //go:generate go run tailscale.com/cmd/cloner  -clonefunc=true -type SliceContainer
 
+// Package clonerex is an example package for the cloner tool.
 package clonerex
 
 type SliceContainer struct {

cmd/containerboot/main.go

@@ -52,6 +52,12 @@
 //     ${TS_CERT_DOMAIN}, it will be replaced with the value of the available FQDN.
 //     It cannot be used in conjunction with TS_DEST_IP. The file is watched for changes,
 //     and will be re-applied when it changes.
+//   - TS_HEALTHCHECK_ADDR_PORT: if specified, an HTTP health endpoint will be
+//     served at /healthz at the provided address, which should be in form [<address>]:<port>.
+//     If not set, no health check will be run. If set to :<port>, addr will default to 0.0.0.0
+//     The health endpoint will return 200 OK if this node has at least one tailnet IP address,
+//     otherwise returns 503.
+//     NB: the health criteria might change in the future.
 //   - TS_EXPERIMENTAL_VERSIONED_CONFIG_DIR: if specified, a path to a
 //     directory that containers tailscaled config in file. The config file needs to be
 //     named cap-<current-tailscaled-cap>.hujson. If this is set, TS_HOSTNAME,
@@ -95,6 +101,7 @@ import (
 	"log"
 	"math"
 	"net"
+	"net/http"
 	"net/netip"
 	"os"
 	"os/exec"
@@ -158,6 +165,7 @@ func main() {
 		AllowProxyingClusterTrafficViaIngress: defaultBool("EXPERIMENTAL_ALLOW_PROXYING_CLUSTER_TRAFFIC_VIA_INGRESS", false),
 		PodIP:                                 defaultEnv("POD_IP", ""),
 		EnableForwardingOptimizations:         defaultBool("TS_EXPERIMENTAL_ENABLE_FORWARDING_OPTIMIZATIONS", false),
+		HealthCheckAddrPort:                   defaultEnv("TS_HEALTHCHECK_ADDR_PORT", ""),
 	}
 
 	if err := cfg.validate(); err != nil {
@@ -349,6 +357,9 @@ authLoop:
 
 		certDomain        = new(atomic.Pointer[string])
 		certDomainChanged = make(chan bool, 1)
+
+		h             = &healthz{} // http server for the healthz endpoint
+		healthzRunner = sync.OnceFunc(func() { runHealthz(cfg.HealthCheckAddrPort, h) })
 	)
 	if cfg.ServeConfigPath != "" {
 		go watchServeConfigChanges(ctx, cfg.ServeConfigPath, certDomainChanged, certDomain, client)
@@ -476,18 +487,20 @@ runLoop:
 					newCurentEgressIPs = deephash.Hash(&egressAddrs)
 					egressIPsHaveChanged = newCurentEgressIPs != currentEgressIPs
 					if egressIPsHaveChanged && len(egressAddrs) != 0 {
+						var rulesInstalled bool
 						for _, egressAddr := range egressAddrs {
 							ea := egressAddr.Addr()
-							// TODO (irbekrm): make it work for IPv6 too.
-							if ea.Is6() {
-								log.Println("Not installing egress forwarding rules for IPv6 as this is currently not supported")
-								continue
-							}
-							log.Printf("Installing forwarding rules for destination %v", ea.String())
-							if err := installEgressForwardingRule(ctx, ea.String(), addrs, nfr); err != nil {
-								log.Fatalf("installing egress proxy rules for destination %s: %v", ea.String(), err)
+							if ea.Is4() || (ea.Is6() && nfr.HasIPV6NAT()) {
+								rulesInstalled = true
+								log.Printf("Installing forwarding rules for destination %v", ea.String())
+								if err := installEgressForwardingRule(ctx, ea.String(), addrs, nfr); err != nil {
+									log.Fatalf("installing egress proxy rules for destination %s: %v", ea.String(), err)
+								}
 							}
 						}
+						if !rulesInstalled {
+							log.Fatalf("no forwarding rules for egress addresses %v, host supports IPv6: %v", egressAddrs, nfr.HasIPV6NAT())
+						}
 					}
 					currentEgressIPs = newCurentEgressIPs
 				}
@@ -563,6 +576,13 @@ runLoop:
 						log.Fatalf("storing device IPs and FQDN in Kubernetes Secret: %v", err)
 					}
 				}
+
+				if cfg.HealthCheckAddrPort != "" {
+					h.Lock()
+					h.hasAddrs = len(addrs) != 0
+					h.Unlock()
+					healthzRunner()
+				}
 			}
 			if !startupTasksDone {
 				// For containerboot instances that act as TCP
@@ -941,7 +961,7 @@ func enableIPForwarding(v4Forwarding, v6Forwarding bool, root string) error {
 	return nil
 }
 
-func installEgressForwardingRule(ctx context.Context, dstStr string, tsIPs []netip.Prefix, nfr linuxfw.NetfilterRunner) error {
+func installEgressForwardingRule(_ context.Context, dstStr string, tsIPs []netip.Prefix, nfr linuxfw.NetfilterRunner) error {
 	dst, err := netip.ParseAddr(dstStr)
 	if err != nil {
 		return err
@@ -1150,7 +1170,8 @@ type settings struct {
 	// PodIP is the IP of the Pod if running in Kubernetes. This is used
 	// when setting up rules to proxy cluster traffic to cluster ingress
 	// target.
-	PodIP string
+	PodIP               string
+	HealthCheckAddrPort string
 }
 
 func (s *settings) validate() error {
@@ -1199,6 +1220,11 @@ func (s *settings) validate() error {
 	if s.EnableForwardingOptimizations && s.UserspaceMode {
 		return errors.New("TS_EXPERIMENTAL_ENABLE_FORWARDING_OPTIMIZATIONS is not supported in userspace mode")
 	}
+	if s.HealthCheckAddrPort != "" {
+		if _, err := netip.ParseAddrPort(s.HealthCheckAddrPort); err != nil {
+			return fmt.Errorf("error parsing TS_HEALTH_CHECK_ADDR_PORT value %q: %w", s.HealthCheckAddrPort, err)
+		}
+	}
 	return nil
 }
 
@@ -1372,3 +1398,41 @@ func tailscaledConfigFilePath() string {
 	log.Printf("Using tailscaled config file %q for capability version %q", maxCompatVer, tailcfg.CurrentCapabilityVersion)
 	return path.Join(dir, kubeutils.TailscaledConfigFileNameForCap(maxCompatVer))
 }
+
+// healthz is a simple health check server, if enabled it returns 200 OK if
+// this tailscale node currently has at least one tailnet IP address else
+// returns 503.
+type healthz struct {
+	sync.Mutex
+	hasAddrs bool
+}
+
+func (h *healthz) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	h.Lock()
+	defer h.Unlock()
+	if h.hasAddrs {
+		w.Write([]byte("ok"))
+	} else {
+		http.Error(w, "node currently has no tailscale IPs", http.StatusInternalServerError)
+	}
+}
+
+// runHealthz runs a simple HTTP health endpoint on /healthz, listening on the
+// provided address. A containerized tailscale instance is considered healthy if
+// it has at least one tailnet IP address.
+func runHealthz(addr string, h *healthz) {
+	lis, err := net.Listen("tcp", addr)
+	if err != nil {
+		log.Fatalf("error listening on the provided health endpoint address %q: %v", addr, err)
+	}
+	mux := http.NewServeMux()
+	mux.Handle("/healthz", h)
+	log.Printf("Running healthcheck endpoint at %s/healthz", addr)
+	hs := &http.Server{Handler: mux}
+
+	go func() {
+		if err := hs.Serve(lis); err != nil {
+			log.Fatalf("failed running health endpoint: %v", err)
+		}
+	}()
+}

cmd/containerboot/main_test.go

@@ -52,7 +52,7 @@ func TestContainerBoot(t *testing.T) {
 	}
 	defer kube.Close()
 
-	tailscaledConf := &ipn.ConfigVAlpha{AuthKey: func(s string) *string { return &s }("foo"), Version: "alpha0"}
+	tailscaledConf := &ipn.ConfigVAlpha{AuthKey: ptr.To("foo"), Version: "alpha0"}
 	tailscaledConfBytes, err := json.Marshal(tailscaledConf)
 	if err != nil {
 		t.Fatalf("error unmarshaling tailscaled config: %v", err)
@@ -116,6 +116,9 @@ func TestContainerBoot(t *testing.T) {
 		// WantFiles files that should exist in the container and their
 		// contents.
 		WantFiles map[string]string
+		// WantFatalLog is the fatal log message we expect from containerboot.
+		// If set for a phase, the test will finish on that phase.
+		WantFatalLog string
 	}
 	runningNotify := &ipn.Notify{
 		State: ptr.To(ipn.Running),
@@ -349,12 +352,57 @@ func TestContainerBoot(t *testing.T) {
 						"/usr/bin/tailscaled --socket=/tmp/tailscaled.sock --state=mem: --statedir=/tmp",
 						"/usr/bin/tailscale --socket=/tmp/tailscaled.sock up --accept-dns=false --authkey=tskey-key",
 					},
+					WantFiles: map[string]string{
+						"proc/sys/net/ipv4/ip_forward":          "1",
+						"proc/sys/net/ipv6/conf/all/forwarding": "0",
+					},
 				},
 				{
 					Notify: runningNotify,
 				},
 			},
 		},
+		{
+			Name: "egress_proxy_fqdn_ipv6_target_on_ipv4_host",
+			Env: map[string]string{
+				"TS_AUTHKEY":               "tskey-key",
+				"TS_TAILNET_TARGET_FQDN":   "ipv6-node.test.ts.net", // resolves to IPv6 address
+				"TS_USERSPACE":             "false",
+				"TS_TEST_FAKE_NETFILTER_6": "false",
+			},
+			Phases: []phase{
+				{
+					WantCmds: []string{
+						"/usr/bin/tailscaled --socket=/tmp/tailscaled.sock --state=mem: --statedir=/tmp",
+						"/usr/bin/tailscale --socket=/tmp/tailscaled.sock up --accept-dns=false --authkey=tskey-key",
+					},
+					WantFiles: map[string]string{
+						"proc/sys/net/ipv4/ip_forward":          "1",
+						"proc/sys/net/ipv6/conf/all/forwarding": "0",
+					},
+				},
+				{
+					Notify: &ipn.Notify{
+						State: ptr.To(ipn.Running),
+						NetMap: &netmap.NetworkMap{
+							SelfNode: (&tailcfg.Node{
+								StableID:  tailcfg.StableNodeID("myID"),
+								Name:      "test-node.test.ts.net",
+								Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
+							}).View(),
+							Peers: []tailcfg.NodeView{
+								(&tailcfg.Node{
+									StableID:  tailcfg.StableNodeID("ipv6ID"),
+									Name:      "ipv6-node.test.ts.net",
+									Addresses: []netip.Prefix{netip.MustParsePrefix("::1/128")},
+								}).View(),
+							},
+						},
+					},
+					WantFatalLog: "no forwarding rules for egress addresses [::1/128], host supports IPv6: false",
+				},
+			},
+		},
 		{
 			Name: "authkey_once",
 			Env: map[string]string{
@@ -697,6 +745,25 @@ func TestContainerBoot(t *testing.T) {
 			var wantCmds []string
 			for i, p := range test.Phases {
 				lapi.Notify(p.Notify)
+				if p.WantFatalLog != "" {
+					err := tstest.WaitFor(2*time.Second, func() error {
+						state, err := cmd.Process.Wait()
+						if err != nil {
+							return err
+						}
+						if state.ExitCode() != 1 {
+							return fmt.Errorf("process exited with code %d but wanted %d", state.ExitCode(), 1)
+						}
+						waitLogLine(t, time.Second, cbOut, p.WantFatalLog)
+						return nil
+					})
+					if err != nil {
+						t.Fatal(err)
+					}
+
+					// Early test return, we don't expect the successful startup log message.
+					return
+				}
 				wantCmds = append(wantCmds, p.WantCmds...)
 				waitArgs(t, 2*time.Second, d, argFile, strings.Join(wantCmds, "\n"))
 				err := tstest.WaitFor(2*time.Second, func() error {

cmd/derper/README.md

@@ -2,7 +2,8 @@
 
 This is the code for the [Tailscale DERP server](https://tailscale.com/kb/1232/derp-servers).
 
-In general, you should not need to nor want to run this code. The overwhelming majority of Tailscale users (both individuals and companies) do not.
+In general, you should not need to or want to run this code. The overwhelming
+majority of Tailscale users (both individuals and companies) do not.
 
 In the happy path, Tailscale establishes direct connections between peers and
 data plane traffic flows directly between them, without using DERP for more than
@@ -11,7 +12,7 @@ find yourself wanting DERP for more bandwidth, the real problem is usually the
 network configuration of your Tailscale node(s), making sure that Tailscale can
 get direction connections via some mechanism.
 
-But if you've decided or been advised to run your own `derper`, then read on.
+If you've decided or been advised to run your own `derper`, then read on.
 
 ## Caveats
 
@@ -28,7 +29,10 @@ But if you've decided or been advised to run your own `derper`, then read on.
 
 * You must build and update the `cmd/derper` binary yourself. There are no
   packages. Use `go install tailscale.com/cmd/derper@latest` with the latest
-  version of Go.
+  version of Go. You should update this binary approximately as regularly as
+  you update Tailscale nodes. If using `--verify-clients`, the `derper` binary
+  and `tailscaled` binary on the machine must be built from the same git revision.
+  (It might work otherwise, but they're developed and only tested together.)
 
 * The DERP protocol does a protocol switch inside TLS from HTTP to a custom
   bidirectional binary protocol. It is thus incompatible with many HTTP proxies.
@@ -55,7 +59,7 @@ rely on its DNS which might be broken and dependent on DERP to get back up.
 * Monitor your DERP servers with [`cmd/derpprobe`](../derpprobe/).
 
 * If using `--verify-clients`, a `tailscaled` must be running alongside the
-  `derper`.
+  `derper`, and all clients must be visible to the derper tailscaled in the ACL.
 
 * If using `--verify-clients`, a `tailscaled` must also be running alongside
   your `derpprobe`, and `derpprobe` needs to use `--derp-map=local`.
@@ -72,3 +76,34 @@ rely on its DNS which might be broken and dependent on DERP to get back up.
 * Don't rate-limit UDP STUN packets.
 
 * Don't rate-limit outbound TCP traffic (only inbound).
+
+## Diagnostics
+
+This is not a complete guide on DERP diagnostics.
+
+Running your own DERP services requires exeprtise in multi-layer network and
+application diagnostics. As the DERP runs multiple protocols at multiple layers
+and is not a regular HTTP(s) server you will need expertise in correlative
+analysis to diagnose the most tricky problems. There is no "plain text" or
+"open" mode of operation for DERP.
+
+* The debug handler is accessible at URL path `/debug/`. It is only accessible
+  over localhost or from a Tailscale IP address.
+
+* Go pprof can be accessed via the debug handler at `/debug/pprof/`
+
+* Prometheus compatible metrics can be gathered from the debug handler at
+  `/debug/varz`.
+
+* `cmd/stunc` in the Tailscale repository provides a basic tool for diagnosing
+  issues with STUN.
+
+* `cmd/derpprobe` provides a service for monitoring DERP cluster health.
+
+* `tailscale debug derp` and `tailscale netcheck` provide additional client
+  driven diagnostic information for DERP communications.
+
+* Tailscale logs may provide insight for certain problems, such as if DERPs are
+  unreachable or peers are regularly not reachable in their DERP home regions.
+  There are many possible misconfiguration causes for these problems, but
+  regular log entries are a good first indicator that there is a problem.

cmd/derper/depaware.txt

@@ -7,9 +7,19 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
    W 💣 github.com/alexbrainman/sspi/negotiate                       from tailscale.com/net/tshttpproxy
         github.com/beorn7/perks/quantile                             from github.com/prometheus/client_golang/prometheus
      💣 github.com/cespare/xxhash/v2                                 from github.com/prometheus/client_golang/prometheus
+        github.com/coder/websocket                                   from tailscale.com/cmd/derper+
+        github.com/coder/websocket/internal/errd                     from github.com/coder/websocket
+        github.com/coder/websocket/internal/util                     from github.com/coder/websocket
+        github.com/coder/websocket/internal/xsync                    from github.com/coder/websocket
    L    github.com/coreos/go-iptables/iptables                       from tailscale.com/util/linuxfw
    W 💣 github.com/dblohm7/wingoes                                   from tailscale.com/util/winutil
         github.com/fxamacker/cbor/v2                                 from tailscale.com/tka
+        github.com/go-json-experiment/json                           from tailscale.com/types/opt+
+        github.com/go-json-experiment/json/internal                  from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonflags        from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonopts         from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonwire         from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/jsontext                  from github.com/go-json-experiment/json+
         github.com/golang/groupcache/lru                             from tailscale.com/net/dnscache
    L    github.com/google/nftables                                   from tailscale.com/util/linuxfw
    L 💣 github.com/google/nftables/alignedbuff                       from github.com/google/nftables/xt
@@ -76,10 +86,6 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         google.golang.org/protobuf/runtime/protoiface                from google.golang.org/protobuf/internal/impl+
         google.golang.org/protobuf/runtime/protoimpl                 from github.com/prometheus/client_model/go+
         google.golang.org/protobuf/types/known/timestamppb           from github.com/prometheus/client_golang/prometheus+
-        nhooyr.io/websocket                                          from tailscale.com/cmd/derper+
-        nhooyr.io/websocket/internal/errd                            from nhooyr.io/websocket
-        nhooyr.io/websocket/internal/util                            from nhooyr.io/websocket
-        nhooyr.io/websocket/internal/xsync                           from nhooyr.io/websocket
         tailscale.com                                                from tailscale.com/version
         tailscale.com/atomicfile                                     from tailscale.com/cmd/derper+
         tailscale.com/client/tailscale                               from tailscale.com/derp
@@ -99,7 +105,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         tailscale.com/net/netaddr                                    from tailscale.com/ipn+
         tailscale.com/net/netknob                                    from tailscale.com/net/netns
      💣 tailscale.com/net/netmon                                     from tailscale.com/derp/derphttp+
-        tailscale.com/net/netns                                      from tailscale.com/derp/derphttp
+     💣 tailscale.com/net/netns                                      from tailscale.com/derp/derphttp
         tailscale.com/net/netutil                                    from tailscale.com/client/tailscale
         tailscale.com/net/sockstats                                  from tailscale.com/derp/derphttp
         tailscale.com/net/stun                                       from tailscale.com/net/stunserver
@@ -114,7 +120,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         tailscale.com/syncs                                          from tailscale.com/cmd/derper+
         tailscale.com/tailcfg                                        from tailscale.com/client/tailscale+
         tailscale.com/tka                                            from tailscale.com/client/tailscale+
-   W    tailscale.com/tsconst                                        from tailscale.com/net/netmon
+   W    tailscale.com/tsconst                                        from tailscale.com/net/netmon+
         tailscale.com/tstime                                         from tailscale.com/derp+
         tailscale.com/tstime/mono                                    from tailscale.com/tstime/rate
         tailscale.com/tstime/rate                                    from tailscale.com/derp
@@ -140,9 +146,11 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         tailscale.com/util/cloudenv                                  from tailscale.com/hostinfo+
    W    tailscale.com/util/cmpver                                    from tailscale.com/net/tshttpproxy
         tailscale.com/util/ctxkey                                    from tailscale.com/tsweb+
+     💣 tailscale.com/util/deephash                                  from tailscale.com/util/syspolicy/setting
    L 💣 tailscale.com/util/dirwalk                                   from tailscale.com/metrics
         tailscale.com/util/dnsname                                   from tailscale.com/hostinfo+
         tailscale.com/util/fastuuid                                  from tailscale.com/tsweb
+     💣 tailscale.com/util/hashx                                     from tailscale.com/util/deephash
         tailscale.com/util/httpm                                     from tailscale.com/client/tailscale
         tailscale.com/util/lineread                                  from tailscale.com/hostinfo+
    L    tailscale.com/util/linuxfw                                   from tailscale.com/net/netns
@@ -153,6 +161,8 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         tailscale.com/util/singleflight                              from tailscale.com/net/dnscache
         tailscale.com/util/slicesx                                   from tailscale.com/cmd/derper+
         tailscale.com/util/syspolicy                                 from tailscale.com/ipn
+        tailscale.com/util/syspolicy/internal                        from tailscale.com/util/syspolicy/setting
+        tailscale.com/util/syspolicy/setting                         from tailscale.com/util/syspolicy
         tailscale.com/util/vizerror                                  from tailscale.com/tailcfg+
    W 💣 tailscale.com/util/winutil                                   from tailscale.com/hostinfo+
    W 💣 tailscale.com/util/winutil/winenv                            from tailscale.com/hostinfo+
@@ -174,6 +184,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
    W    golang.org/x/exp/constraints                                 from tailscale.com/util/winutil
+        golang.org/x/exp/maps                                        from tailscale.com/util/syspolicy/setting
    L    golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
         golang.org/x/net/dns/dnsmessage                              from net+
         golang.org/x/net/http/httpguts                               from net/http

cmd/derper/derper.go

@@ -2,6 +2,12 @@
 // SPDX-License-Identifier: BSD-3-Clause
 
 // The derper binary is a simple DERP server.
+//
+// For more information, see:
+//
+//   - About: https://tailscale.com/kb/1232/derp-servers
+//   - Protocol & Go docs: https://pkg.go.dev/tailscale.com/derp
+//   - Running a DERP server: https://github.com/tailscale/tailscale/tree/main/cmd/derper#derp
 package main // import "tailscale.com/cmd/derper"
 
 import (
@@ -22,6 +28,9 @@ import (
 	"os/signal"
 	"path/filepath"
 	"regexp"
+	"runtime"
+	runtimemetrics "runtime/metrics"
+	"strconv"
 	"strings"
 	"syscall"
 	"time"
@@ -206,11 +215,16 @@ func main() {
 		io.WriteString(w, `<html><body>
 <h1>DERP</h1>
 <p>
-  This is a
-  <a href="https://tailscale.com/">Tailscale</a>
-  <a href="https://pkg.go.dev/tailscale.com/derp">DERP</a>
-  server.
+  This is a <a href="https://tailscale.com/">Tailscale</a> DERP server.
 </p>
+<p>
+  Documentation:
+</p>
+<ul>
+  <li><a href="https://tailscale.com/kb/1232/derp-servers">About DERP</a></li>
+  <li><a href="https://pkg.go.dev/tailscale.com/derp">Protocol & Go docs</a></li>
+  <li><a href="https://github.com/tailscale/tailscale/tree/main/cmd/derper#derp">How to run a DERP server</a></li>
+</ul>
 `)
 		if !*runDERP {
 			io.WriteString(w, `<p>Status: <b>disabled</b></p>`)
@@ -223,7 +237,7 @@ func main() {
 		tsweb.AddBrowserHeaders(w)
 		io.WriteString(w, "User-agent: *\nDisallow: /\n")
 	}))
-	mux.Handle("/generate_204", http.HandlerFunc(serveNoContent))
+	mux.Handle("/generate_204", http.HandlerFunc(derphttp.ServeNoContent))
 	debug := tsweb.Debugger(mux)
 	debug.KV("TLS hostname", *hostname)
 	debug.KV("Mesh key", s.HasMeshKey())
@@ -236,6 +250,20 @@ func main() {
 		}
 	}))
 	debug.Handle("traffic", "Traffic check", http.HandlerFunc(s.ServeDebugTraffic))
+	debug.Handle("set-mutex-profile-fraction", "SetMutexProfileFraction", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		s := r.FormValue("rate")
+		if s == "" || r.Header.Get("Sec-Debug") != "derp" {
+			http.Error(w, "To set, use: curl -HSec-Debug:derp 'http://derp/debug/set-mutex-profile-fraction?rate=100'", http.StatusBadRequest)
+			return
+		}
+		v, err := strconv.Atoi(s)
+		if err != nil {
+			http.Error(w, "bad rate value", http.StatusBadRequest)
+			return
+		}
+		old := runtime.SetMutexProfileFraction(v)
+		fmt.Fprintf(w, "mutex changed from %v to %v\n", old, v)
+	}))
 
 	// Longer lived DERP connections send an application layer keepalive. Note
 	// if the keepalive is hit, the user timeout will take precedence over the
@@ -309,7 +337,7 @@ func main() {
 		if *httpPort > -1 {
 			go func() {
 				port80mux := http.NewServeMux()
-				port80mux.HandleFunc("/generate_204", serveNoContent)
+				port80mux.HandleFunc("/generate_204", derphttp.ServeNoContent)
 				port80mux.Handle("/", certManager.HTTPHandler(tsweb.Port80Handler{Main: mux}))
 				port80srv := &http.Server{
 					Addr:        net.JoinHostPort(listenHost, fmt.Sprintf("%d", *httpPort)),
@@ -350,31 +378,6 @@ func main() {
 	}
 }
 
-const (
-	noContentChallengeHeader = "X-Tailscale-Challenge"
-	noContentResponseHeader  = "X-Tailscale-Response"
-)
-
-// For captive portal detection
-func serveNoContent(w http.ResponseWriter, r *http.Request) {
-	if challenge := r.Header.Get(noContentChallengeHeader); challenge != "" {
-		badChar := strings.IndexFunc(challenge, func(r rune) bool {
-			return !isChallengeChar(r)
-		}) != -1
-		if len(challenge) <= 64 && !badChar {
-			w.Header().Set(noContentResponseHeader, "response "+challenge)
-		}
-	}
-	w.WriteHeader(http.StatusNoContent)
-}
-
-func isChallengeChar(c rune) bool {
-	// Semi-randomly chosen as a limited set of valid characters
-	return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') ||
-		('0' <= c && c <= '9') ||
-		c == '.' || c == '-' || c == '_'
-}
-
 var validProdHostname = regexp.MustCompile(`^derp([^.]*)\.tailscale\.com\.?$`)
 
 func prodAutocertHostPolicy(_ context.Context, host string) error {
@@ -452,3 +455,16 @@ func (l *rateLimitedListener) Accept() (net.Conn, error) {
 	l.numAccepts.Add(1)
 	return cn, nil
 }
+
+func init() {
+	expvar.Publish("go_sync_mutex_wait_seconds", expvar.Func(func() any {
+		const name = "/sync/mutex/wait/total:seconds" // Go 1.20+
+		var s [1]runtimemetrics.Sample
+		s[0].Name = name
+		runtimemetrics.Read(s[:])
+		if v := s[0].Value; v.Kind() == runtimemetrics.KindFloat64 {
+			return v.Float64()
+		}
+		return 0
+	}))
+}

cmd/derper/derper_test.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 	"testing"
 
+	"tailscale.com/derp/derphttp"
 	"tailscale.com/tstest/deptest"
 )
 
@@ -76,20 +77,20 @@ func TestNoContent(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			req, _ := http.NewRequest("GET", "https://localhost/generate_204", nil)
 			if tt.input != "" {
-				req.Header.Set(noContentChallengeHeader, tt.input)
+				req.Header.Set(derphttp.NoContentChallengeHeader, tt.input)
 			}
 			w := httptest.NewRecorder()
-			serveNoContent(w, req)
+			derphttp.ServeNoContent(w, req)
 			resp := w.Result()
 
 			if tt.want == "" {
-				if h, found := resp.Header[noContentResponseHeader]; found {
+				if h, found := resp.Header[derphttp.NoContentResponseHeader]; found {
 					t.Errorf("got %+v; expected no response header", h)
 				}
 				return
 			}
 
-			if got := resp.Header.Get(noContentResponseHeader); got != tt.want {
+			if got := resp.Header.Get(derphttp.NoContentResponseHeader); got != tt.want {
 				t.Errorf("got %q; want %q", got, tt.want)
 			}
 		})

cmd/derper/mesh.go

@@ -9,14 +9,12 @@ import (
 	"fmt"
 	"log"
 	"net"
-	"net/netip"
 	"strings"
 	"time"
 
 	"tailscale.com/derp"
 	"tailscale.com/derp/derphttp"
 	"tailscale.com/net/netmon"
-	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
 )
 
@@ -71,8 +69,8 @@ func startMeshWithHost(s *derp.Server, host string) error {
 		return d.DialContext(ctx, network, addr)
 	})
 
-	add := func(k key.NodePublic, _ netip.AddrPort) { s.AddPacketForwarder(k, c) }
-	remove := func(k key.NodePublic) { s.RemovePacketForwarder(k, c) }
+	add := func(m derp.PeerPresentMessage) { s.AddPacketForwarder(m.Key, c) }
+	remove := func(m derp.PeerGoneMessage) { s.RemovePacketForwarder(m.Peer, c) }
 	go c.RunWatchConnectionLoop(context.Background(), s.PublicKey(), logf, add, remove)
 	return nil
 }

cmd/derper/websocket.go

@@ -10,7 +10,7 @@ import (
 	"net/http"
 	"strings"
 
-	"nhooyr.io/websocket"
+	"github.com/coder/websocket"
 	"tailscale.com/derp"
 	"tailscale.com/net/wsconn"
 )

cmd/derpprobe/derpprobe.go

@@ -7,8 +7,6 @@ package main
 import (
 	"flag"
 	"fmt"
-	"html"
-	"io"
 	"log"
 	"net/http"
 	"sort"
@@ -70,8 +68,13 @@ func main() {
 	}
 
 	mux := http.NewServeMux()
-	tsweb.Debugger(mux)
-	mux.HandleFunc("/", http.HandlerFunc(serveFunc(p)))
+	d := tsweb.Debugger(mux)
+	d.Handle("probe-run", "Run a probe", tsweb.StdHandler(tsweb.ReturnHandlerFunc(p.RunHandler), tsweb.HandlerOptions{Logf: log.Printf}))
+	mux.Handle("/", tsweb.StdHandler(p.StatusHandler(
+		prober.WithTitle("DERP Prober"),
+		prober.WithPageLink("Prober metrics", "/debug/varz"),
+		prober.WithProbeLink("Run Probe", "/debug/probe-run?name={{.Name}}"),
+	), tsweb.HandlerOptions{Logf: log.Printf}))
 	log.Printf("Listening on %s", *listen)
 	log.Fatal(http.ListenAndServe(*listen, mux))
 }
@@ -105,26 +108,3 @@ func getOverallStatus(p *prober.Prober) (o overallStatus) {
 	sort.Strings(o.good)
 	return
 }
-
-func serveFunc(p *prober.Prober) func(w http.ResponseWriter, r *http.Request) {
-	return func(w http.ResponseWriter, r *http.Request) {
-		st := getOverallStatus(p)
-		summary := "All good"
-		if (float64(len(st.bad)) / float64(len(st.bad)+len(st.good))) > 0.25 {
-			// Returning a 500 allows monitoring this server externally and configuring
-			// an alert on HTTP response code.
-			w.WriteHeader(500)
-			summary = fmt.Sprintf("%d problems", len(st.bad))
-		}
-
-		io.WriteString(w, "<html><head><style>.bad { font-weight: bold; color: #700; }</style></head>\n")
-		fmt.Fprintf(w, "<body><h1>derp probe</h1>\n%s:<ul>", summary)
-		for _, s := range st.bad {
-			fmt.Fprintf(w, "<li class=bad>%s</li>\n", html.EscapeString(s))
-		}
-		for _, s := range st.good {
-			fmt.Fprintf(w, "<li>%s</li>\n", html.EscapeString(s))
-		}
-		io.WriteString(w, "</ul></body></html>\n")
-	}
-}

cmd/gitops-pusher/gitops-pusher.go

@@ -28,19 +28,20 @@ import (
 )
 
 var (
-	rootFlagSet  = flag.NewFlagSet("gitops-pusher", flag.ExitOnError)
-	policyFname  = rootFlagSet.String("policy-file", "./policy.hujson", "filename for policy file")
-	cacheFname   = rootFlagSet.String("cache-file", "./version-cache.json", "filename for the previous known version hash")
-	timeout      = rootFlagSet.Duration("timeout", 5*time.Minute, "timeout for the entire CI run")
-	githubSyntax = rootFlagSet.Bool("github-syntax", true, "use GitHub Action error syntax (https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-error-message)")
-	apiServer    = rootFlagSet.String("api-server", "api.tailscale.com", "API server to contact")
+	rootFlagSet       = flag.NewFlagSet("gitops-pusher", flag.ExitOnError)
+	policyFname       = rootFlagSet.String("policy-file", "./policy.hujson", "filename for policy file")
+	cacheFname        = rootFlagSet.String("cache-file", "./version-cache.json", "filename for the previous known version hash")
+	timeout           = rootFlagSet.Duration("timeout", 5*time.Minute, "timeout for the entire CI run")
+	githubSyntax      = rootFlagSet.Bool("github-syntax", true, "use GitHub Action error syntax (https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-error-message)")
+	apiServer         = rootFlagSet.String("api-server", "api.tailscale.com", "API server to contact")
+	failOnManualEdits = rootFlagSet.Bool("fail-on-manual-edits", false, "fail if manual edits to the ACLs in the admin panel are detected; when set to false (the default) only a warning is printed")
 )
 
-func modifiedExternallyError() {
+func modifiedExternallyError() error {
 	if *githubSyntax {
-		fmt.Printf("::warning file=%s,line=1,col=1,title=Policy File Modified Externally::The policy file was modified externally in the admin console.\n", *policyFname)
+		return fmt.Errorf("::warning file=%s,line=1,col=1,title=Policy File Modified Externally::The policy file was modified externally in the admin console.", *policyFname)
 	} else {
-		fmt.Printf("The policy file was modified externally in the admin console.\n")
+		return fmt.Errorf("The policy file was modified externally in the admin console.")
 	}
 }
 
@@ -65,16 +66,22 @@ func apply(cache *Cache, client *http.Client, tailnet, apiKey string) func(conte
 		log.Printf("local:   %s", localEtag)
 		log.Printf("cache:   %s", cache.PrevETag)
 
-		if cache.PrevETag != controlEtag {
-			modifiedExternallyError()
-		}
-
 		if controlEtag == localEtag {
 			cache.PrevETag = localEtag
 			log.Println("no update needed, doing nothing")
 			return nil
 		}
 
+		if cache.PrevETag != controlEtag {
+			if err := modifiedExternallyError(); err != nil {
+				if *failOnManualEdits {
+					return err
+				} else {
+					fmt.Println(err)
+				}
+			}
+		}
+
 		if err := applyNewACL(ctx, client, tailnet, apiKey, *policyFname, controlEtag); err != nil {
 			return err
 		}
@@ -106,15 +113,21 @@ func test(cache *Cache, client *http.Client, tailnet, apiKey string) func(contex
 		log.Printf("local:   %s", localEtag)
 		log.Printf("cache:   %s", cache.PrevETag)
 
-		if cache.PrevETag != controlEtag {
-			modifiedExternallyError()
-		}
-
 		if controlEtag == localEtag {
 			log.Println("no updates found, doing nothing")
 			return nil
 		}
 
+		if cache.PrevETag != controlEtag {
+			if err := modifiedExternallyError(); err != nil {
+				if *failOnManualEdits {
+					return err
+				} else {
+					fmt.Println(err)
+				}
+			}
+		}
+
 		if err := testNewACLs(ctx, client, tailnet, apiKey, *policyFname); err != nil {
 			return err
 		}

cmd/k8s-operator/deploy/chart/templates/deployment.yaml

@@ -77,6 +77,13 @@ spec:
               value: "{{ .Values.apiServerProxyConfig.mode }}"
             - name: PROXY_FIREWALL_MODE
               value: {{ .Values.proxyConfig.firewallMode }}
+            {{- if .Values.proxyConfig.defaultProxyClass }}
+            - name: PROXY_DEFAULT_CLASS
+              value: {{ .Values.proxyConfig.defaultProxyClass }}
+            {{- end }}
+            {{- with .Values.operatorConfig.extraEnv }}
+            {{- toYaml . | nindent 12 }}
+            {{- end }}
           volumeMounts:
           - name: oauth
             mountPath: /oauth

cmd/k8s-operator/deploy/chart/templates/operator-rbac.yaml

@@ -14,10 +14,10 @@ metadata:
 rules:
 - apiGroups: [""]
   resources: ["events", "services", "services/status"]
-  verbs: ["*"]
+  verbs: ["create","delete","deletecollection","get","list","patch","update","watch"]
 - apiGroups: ["networking.k8s.io"]
   resources: ["ingresses", "ingresses/status"]
-  verbs: ["*"]
+  verbs: ["create","delete","deletecollection","get","list","patch","update","watch"]
 - apiGroups: ["networking.k8s.io"]
   resources: ["ingressclasses"]
   verbs: ["get", "list", "watch"]
@@ -49,10 +49,10 @@ metadata:
 rules:
 - apiGroups: [""]
   resources: ["secrets", "serviceaccounts", "configmaps"]
-  verbs: ["*"]
+  verbs: ["create","delete","deletecollection","get","list","patch","update","watch"]
 - apiGroups: ["apps"]
   resources: ["statefulsets", "deployments"]
-  verbs: ["*"]
+  verbs: ["create","delete","deletecollection","get","list","patch","update","watch"]
 - apiGroups: ["discovery.k8s.io"]
   resources: ["endpointslices"]
   verbs: ["get", "list", "watch"]

cmd/k8s-operator/deploy/chart/templates/proxy-rbac.yaml

@@ -15,7 +15,7 @@ metadata:
 rules:
 - apiGroups: [""]
   resources: ["secrets"]
-  verbs: ["*"]
+  verbs: ["create","delete","deletecollection","get","list","patch","update","watch"]
 ---
 apiVersion: rbac.authorization.k8s.io/v1
 kind: RoleBinding

cmd/k8s-operator/deploy/chart/values.yaml

@@ -48,6 +48,13 @@ operatorConfig:
 
   securityContext: {}
 
+  extraEnv: []
+  # - name: EXTRA_VAR1
+  #   value: "value1"
+  # - name: EXTRA_VAR2
+  #   value: "value2"
+
+
 # proxyConfig contains configuraton that will be applied to any ingress/egress
 # proxies created by the operator.
 # https://tailscale.com/kb/1236/kubernetes-operator/#cluster-ingress
@@ -71,6 +78,9 @@ proxyConfig:
   # Note that if you pass multiple tags to this field via `--set` flag to helm upgrade/install commands you must escape the comma (for example, "tag:k8s-proxies\,tag:prod"). See https://github.com/helm/helm/issues/1556
   defaultTags: "tag:k8s"
   firewallMode: auto
+  # If defined, this proxy class will be used as the default proxy class for
+  # service and ingress resources that do not have a proxy class defined.
+  defaultProxyClass: ""
 
 # apiServerProxyConfig allows to configure whether the operator should expose
 # Kubernetes API server.

cmd/k8s-operator/deploy/manifests/operator.yaml

@@ -2428,14 +2428,28 @@ rules:
         - services
         - services/status
       verbs:
-        - '*'
+        - create
+        - delete
+        - deletecollection
+        - get
+        - list
+        - patch
+        - update
+        - watch
     - apiGroups:
         - networking.k8s.io
       resources:
         - ingresses
         - ingresses/status
       verbs:
-        - '*'
+        - create
+        - delete
+        - deletecollection
+        - get
+        - list
+        - patch
+        - update
+        - watch
     - apiGroups:
         - networking.k8s.io
       resources:
@@ -2493,14 +2507,28 @@ rules:
         - serviceaccounts
         - configmaps
       verbs:
-        - '*'
+        - create
+        - delete
+        - deletecollection
+        - get
+        - list
+        - patch
+        - update
+        - watch
     - apiGroups:
         - apps
       resources:
         - statefulsets
         - deployments
       verbs:
-        - '*'
+        - create
+        - delete
+        - deletecollection
+        - get
+        - list
+        - patch
+        - update
+        - watch
     - apiGroups:
         - discovery.k8s.io
       resources:
@@ -2521,7 +2549,14 @@ rules:
       resources:
         - secrets
       verbs:
-        - '*'
+        - create
+        - delete
+        - deletecollection
+        - get
+        - list
+        - patch
+        - update
+        - watch
 ---
 apiVersion: rbac.authorization.k8s.io/v1
 kind: RoleBinding

cmd/k8s-operator/dnsrecords.go

@@ -3,9 +3,6 @@
 
 //go:build !plan9
 
-// tailscale-operator provides a way to expose services running in a Kubernetes
-// cluster to your Tailnet and to make Tailscale nodes available to cluster
-// workloads
 package main
 
 import (
@@ -27,6 +24,7 @@ import (
 	operatorutils "tailscale.com/k8s-operator"
 	tsapi "tailscale.com/k8s-operator/apis/v1alpha1"
 	"tailscale.com/util/mak"
+	"tailscale.com/util/set"
 )
 
 const (
@@ -170,36 +168,49 @@ func (dnsRR *dnsRecordsReconciler) maybeProvision(ctx context.Context, headlessS
 		}
 	}
 
-	// Get the Pod IP addresses for the proxy from the EndpointSlice for the
-	// headless Service.
+	// Get the Pod IP addresses for the proxy from the EndpointSlices for
+	// the headless Service. The Service can have multiple EndpointSlices
+	// associated with it, for example in dual-stack clusters.
 	labels := map[string]string{discoveryv1.LabelServiceName: headlessSvc.Name} // https://kubernetes.io/docs/concepts/services-networking/endpoint-slices/#ownership
-	eps, err := getSingleObject[discoveryv1.EndpointSlice](ctx, dnsRR.Client, dnsRR.tsNamespace, labels)
-	if err != nil {
-		return fmt.Errorf("error getting the EndpointSlice for the proxy's headless Service: %w", err)
+	var eps = new(discoveryv1.EndpointSliceList)
+	if err := dnsRR.List(ctx, eps, client.InNamespace(dnsRR.tsNamespace), client.MatchingLabels(labels)); err != nil {
+		return fmt.Errorf("error listing EndpointSlices for the proxy's headless Service: %w", err)
 	}
-	if eps == nil {
+	if len(eps.Items) == 0 {
 		logger.Debugf("proxy's headless Service EndpointSlice does not yet exist. We will reconcile again once it's created")
 		return nil
 	}
-	// An EndpointSlice for a Service can have a list of endpoints that each
+	// Each EndpointSlice for a Service can have a list of endpoints that each
 	// can have multiple addresses - these are the IP addresses of any Pods
 	// selected by that Service. Pick all the IPv4 addresses.
-	ips := make([]string, 0)
-	for _, ep := range eps.Endpoints {
-		for _, ip := range ep.Addresses {
-			if !net.IsIPv4String(ip) {
-				logger.Infof("EndpointSlice contains IP address %q that is not IPv4, ignoring. Currently only IPv4 is supported", ip)
-			} else {
-				ips = append(ips, ip)
+	// It is also possible that multiple EndpointSlices have overlapping addresses.
+	// https://kubernetes.io/docs/concepts/services-networking/endpoint-slices/#duplicate-endpoints
+	ips := make(set.Set[string], 0)
+	for _, slice := range eps.Items {
+		if slice.AddressType != discoveryv1.AddressTypeIPv4 {
+			logger.Infof("EndpointSlice is for AddressType %s, currently only IPv4 address type is supported", slice.AddressType)
+			continue
+		}
+		for _, ep := range slice.Endpoints {
+			if !epIsReady(&ep) {
+				logger.Debugf("Endpoint with addresses %v appears not ready to receive traffic %v", ep.Addresses, ep.Conditions.String())
+				continue
+			}
+			for _, ip := range ep.Addresses {
+				if !net.IsIPv4String(ip) {
+					logger.Infof("EndpointSlice contains IP address %q that is not IPv4, ignoring. Currently only IPv4 is supported", ip)
+				} else {
+					ips.Add(ip)
+				}
 			}
 		}
 	}
-	if len(ips) == 0 {
+	if ips.Len() == 0 {
 		logger.Debugf("EndpointSlice for the Service contains no IPv4 addresses. We will reconcile again once they are created.")
 		return nil
 	}
 	updateFunc := func(rec *operatorutils.Records) {
-		mak.Set(&rec.IP4, fqdn, ips)
+		mak.Set(&rec.IP4, fqdn, ips.Slice())
 	}
 	if err = dnsRR.updateDNSConfig(ctx, updateFunc); err != nil {
 		return fmt.Errorf("error updating DNS records: %w", err)
@@ -207,6 +218,17 @@ func (dnsRR *dnsRecordsReconciler) maybeProvision(ctx context.Context, headlessS
 	return nil
 }
 
+// epIsReady reports whether the endpoint is currently in a state to receive new
+// traffic. As per kube docs, only explicitly set 'false' for 'Ready' or
+// 'Serving' conditions or explicitly set 'true' for 'Terminating' condition
+// means that the Endpoint is NOT ready.
+// https://github.com/kubernetes/kubernetes/blob/60c4c2b2521fb454ce69dee737e3eb91a25e0535/pkg/apis/discovery/types.go#L109-L131
+func epIsReady(ep *discoveryv1.Endpoint) bool {
+	return (ep.Conditions.Ready == nil || *ep.Conditions.Ready) &&
+		(ep.Conditions.Serving == nil || *ep.Conditions.Serving) &&
+		(ep.Conditions.Terminating == nil || !*ep.Conditions.Terminating)
+}
+
 // maybeCleanup ensures that the DNS record for the proxy has been removed from
 // dnsrecords ConfigMap and the tailscale.com/dns-records-reconciler finalizer
 // has been removed from the Service. If the record is not found in the

cmd/k8s-operator/dnsrecords_test.go

@@ -8,6 +8,7 @@ package main
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -87,13 +88,16 @@ func TestDNSRecordsReconciler(t *testing.T) {
 		},
 	}
 	headlessForEgressSvcFQDN := headlessSvcForParent(egressSvcFQDN, "svc") // create the proxy headless Service
-	ep := endpointSliceForService(headlessForEgressSvcFQDN, "10.9.8.7")
+	ep := endpointSliceForService(headlessForEgressSvcFQDN, "10.9.8.7", discoveryv1.AddressTypeIPv4)
+	epv6 := endpointSliceForService(headlessForEgressSvcFQDN, "2600:1900:4011:161:0:d:0:d", discoveryv1.AddressTypeIPv6)
+
 	mustCreate(t, fc, egressSvcFQDN)
 	mustCreate(t, fc, headlessForEgressSvcFQDN)
 	mustCreate(t, fc, ep)
+	mustCreate(t, fc, epv6)
 	expectReconciled(t, dnsRR, "tailscale", "egress-fqdn") // dns-records-reconciler reconcile the headless Service
 	// ConfigMap should now have a record for foo.bar.ts.net -> 10.8.8.7
-	wantHosts := map[string][]string{"foo.bar.ts.net": {"10.9.8.7"}}
+	wantHosts := map[string][]string{"foo.bar.ts.net": {"10.9.8.7"}} // IPv6 endpoint is currently ignored
 	expectHostsRecords(t, fc, wantHosts)
 
 	// 2. DNS record is updated if tailscale.com/tailnet-fqdn annotation's
@@ -106,7 +110,7 @@ func TestDNSRecordsReconciler(t *testing.T) {
 	expectHostsRecords(t, fc, wantHosts)
 
 	// 3. DNS record is updated if the IP address of the proxy Pod changes.
-	ep = endpointSliceForService(headlessForEgressSvcFQDN, "10.6.5.4")
+	ep = endpointSliceForService(headlessForEgressSvcFQDN, "10.6.5.4", discoveryv1.AddressTypeIPv4)
 	mustUpdate(t, fc, ep.Namespace, ep.Name, func(ep *discoveryv1.EndpointSlice) {
 		ep.Endpoints[0].Addresses = []string{"10.6.5.4"}
 	})
@@ -116,7 +120,7 @@ func TestDNSRecordsReconciler(t *testing.T) {
 
 	// 4. DNS record is created for an ingress proxy configured via Ingress
 	headlessForIngress := headlessSvcForParent(ing, "ingress")
-	ep = endpointSliceForService(headlessForIngress, "10.9.8.7")
+	ep = endpointSliceForService(headlessForIngress, "10.9.8.7", discoveryv1.AddressTypeIPv4)
 	mustCreate(t, fc, headlessForIngress)
 	mustCreate(t, fc, ep)
 	expectReconciled(t, dnsRR, "tailscale", "ts-ingress") // dns-records-reconciler should reconcile the headless Service
@@ -140,6 +144,17 @@ func TestDNSRecordsReconciler(t *testing.T) {
 	expectReconciled(t, dnsRR, "tailscale", "ts-ingress")
 	wantHosts["another.ingress.ts.net"] = []string{"7.8.9.10"}
 	expectHostsRecords(t, fc, wantHosts)
+
+	// 7. A not-ready Endpoint is removed from DNS config.
+	mustUpdate(t, fc, ep.Namespace, ep.Name, func(ep *discoveryv1.EndpointSlice) {
+		ep.Endpoints[0].Conditions.Ready = ptr.To(false)
+		ep.Endpoints = append(ep.Endpoints, discoveryv1.Endpoint{
+			Addresses: []string{"1.2.3.4"},
+		})
+	})
+	expectReconciled(t, dnsRR, "tailscale", "ts-ingress")
+	wantHosts["another.ingress.ts.net"] = []string{"1.2.3.4"}
+	expectHostsRecords(t, fc, wantHosts)
 }
 
 func headlessSvcForParent(o client.Object, typ string) *corev1.Service {
@@ -162,15 +177,21 @@ func headlessSvcForParent(o client.Object, typ string) *corev1.Service {
 	}
 }
 
-func endpointSliceForService(svc *corev1.Service, ip string) *discoveryv1.EndpointSlice {
+func endpointSliceForService(svc *corev1.Service, ip string, fam discoveryv1.AddressType) *discoveryv1.EndpointSlice {
 	return &discoveryv1.EndpointSlice{
 		ObjectMeta: metav1.ObjectMeta{
-			Name:      svc.Name,
+			Name:      fmt.Sprintf("%s-%s", svc.Name, string(fam)),
 			Namespace: svc.Namespace,
 			Labels:    map[string]string{discoveryv1.LabelServiceName: svc.Name},
 		},
+		AddressType: fam,
 		Endpoints: []discoveryv1.Endpoint{{
 			Addresses: []string{ip},
+			Conditions: discoveryv1.EndpointConditions{
+				Ready:       ptr.To(true),
+				Serving:     ptr.To(true),
+				Terminating: ptr.To(false),
+			},
 		}},
 	}
 }

cmd/k8s-operator/generate/main.go

@@ -3,6 +3,7 @@
 
 //go:build !plan9
 
+// The generate command creates tailscale.com CRDs.
 package main
 
 import (

cmd/k8s-operator/ingress.go

@@ -46,6 +46,8 @@ type IngressReconciler struct {
 	// managedIngresses is a set of all ingress resources that we're currently
 	// managing. This is only used for metrics.
 	managedIngresses set.Slice[types.UID]
+
+	proxyDefaultClass string
 }
 
 var (
@@ -133,7 +135,7 @@ func (a *IngressReconciler) maybeProvision(ctx context.Context, logger *zap.Suga
 		}
 	}
 
-	proxyClass := proxyClassForObject(ing)
+	proxyClass := proxyClassForObject(ing, a.proxyDefaultClass)
 	if proxyClass != "" {
 		if ready, err := proxyClassIsReady(ctx, proxyClass, a.Client); err != nil {
 			return fmt.Errorf("error verifying ProxyClass for Ingress: %w", err)

cmd/k8s-operator/operator.go

@@ -51,8 +51,8 @@ import (
 // Generate static manifests for deploying Tailscale operator on Kubernetes from the operator's Helm chart.
 //go:generate go run tailscale.com/cmd/k8s-operator/generate staticmanifests
 
-// Generate CRD docs from the yamls
-//go:generate go run fybrik.io/crdoc --resources=./deploy/crds --output=../../k8s-operator/api.md
+// Generate CRD API docs.
+//go:generate go run github.com/elastic/crd-ref-docs --renderer=markdown --source-path=../../k8s-operator/apis/ --config=../../k8s-operator/api-docs-config.yaml --output-path=../../k8s-operator/api.md
 
 func main() {
 	// Required to use our client API. We're fine with the instability since the
@@ -66,6 +66,7 @@ func main() {
 		priorityClassName     = defaultEnv("PROXY_PRIORITY_CLASS_NAME", "")
 		tags                  = defaultEnv("PROXY_TAGS", "tag:k8s")
 		tsFirewallMode        = defaultEnv("PROXY_FIREWALL_MODE", "")
+		defaultProxyClass     = defaultEnv("PROXY_DEFAULT_CLASS", "")
 		isDefaultLoadBalancer = defaultBool("OPERATOR_DEFAULT_LOAD_BALANCER", false)
 	)
 
@@ -106,6 +107,7 @@ func main() {
 		proxyActAsDefaultLoadBalancer: isDefaultLoadBalancer,
 		proxyTags:                     tags,
 		proxyFirewallMode:             tsFirewallMode,
+		proxyDefaultClass:             defaultProxyClass,
 	}
 	runReconcilers(rOpts)
 }
@@ -279,6 +281,7 @@ func runReconcilers(opts reconcilerOpts) {
 			recorder:              eventRecorder,
 			tsNamespace:           opts.tailscaleNamespace,
 			clock:                 tstime.DefaultClock{},
+			proxyDefaultClass:     opts.proxyDefaultClass,
 		})
 	if err != nil {
 		startlog.Fatalf("could not create service reconciler: %v", err)
@@ -301,6 +304,7 @@ func runReconcilers(opts reconcilerOpts) {
 			recorder: eventRecorder,
 			Client:   mgr.GetClient(),
 			logger:   opts.log.Named("ingress-reconciler"),
+			proxyDefaultClass: opts.proxyDefaultClass,
 		})
 	if err != nil {
 		startlog.Fatalf("could not create ingress reconciler: %v", err)
@@ -424,6 +428,10 @@ type reconcilerOpts struct {
 	// Auto is usually the best choice, unless you want to explicitly set
 	// specific mode for debugging purposes.
 	proxyFirewallMode string
+	// proxyDefaultClass is the name of the ProxyClass to use as the default
+	// class for proxies that do not have a ProxyClass set.
+	// this is defined by an operator env variable.
+	proxyDefaultClass string
 }
 
 // enqueueAllIngressEgressProxySvcsinNS returns a reconcile request for each

cmd/k8s-operator/proxy.go

@@ -11,15 +11,18 @@ import (
 	"log"
 	"net/http"
 	"net/http/httputil"
+	"net/netip"
 	"net/url"
 	"os"
 	"strings"
 
+	"github.com/pkg/errors"
 	"go.uber.org/zap"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/transport"
 	"tailscale.com/client/tailscale"
 	"tailscale.com/client/tailscale/apitype"
+	ksr "tailscale.com/k8s-operator/sessionrecording"
 	tskube "tailscale.com/kube"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tsnet"
@@ -30,10 +33,26 @@ import (
 
 var whoIsKey = ctxkey.New("", (*apitype.WhoIsResponse)(nil))
 
-var counterNumRequestsProxied = clientmetric.NewCounter("k8s_auth_proxy_requests_proxied")
+var (
+	// counterNumRequestsproxies counts the number of API server requests proxied via this proxy.
+	counterNumRequestsProxied = clientmetric.NewCounter("k8s_auth_proxy_requests_proxied")
+)
 
 type apiServerProxyMode int
 
+func (a apiServerProxyMode) String() string {
+	switch a {
+	case apiserverProxyModeDisabled:
+		return "disabled"
+	case apiserverProxyModeEnabled:
+		return "auth"
+	case apiserverProxyModeNoAuth:
+		return "noauth"
+	default:
+		return "unknown"
+	}
+}
+
 const (
 	apiserverProxyModeDisabled apiServerProxyMode = iota
 	apiserverProxyModeEnabled
@@ -97,26 +116,7 @@ func maybeLaunchAPIServerProxy(zlog *zap.SugaredLogger, restConfig *rest.Config,
 	if err != nil {
 		startlog.Fatalf("could not get rest.TransportConfig(): %v", err)
 	}
-	go runAPIServerProxy(s, rt, zlog.Named("apiserver-proxy"), mode)
-}
-
-// apiserverProxy is an http.Handler that authenticates requests using the Tailscale
-// LocalAPI and then proxies them to the Kubernetes API.
-type apiserverProxy struct {
-	log *zap.SugaredLogger
-	lc  *tailscale.LocalClient
-	rp  *httputil.ReverseProxy
-}
-
-func (h *apiserverProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	who, err := h.lc.WhoIs(r.Context(), r.RemoteAddr)
-	if err != nil {
-		h.log.Errorf("failed to authenticate caller: %v", err)
-		http.Error(w, "failed to authenticate caller", http.StatusInternalServerError)
-		return
-	}
-	counterNumRequestsProxied.Add(1)
-	h.rp.ServeHTTP(w, r.WithContext(whoIsKey.WithValue(r.Context(), who)))
+	go runAPIServerProxy(s, rt, zlog.Named("apiserver-proxy"), mode, restConfig.Host)
 }
 
 // runAPIServerProxy runs an HTTP server that authenticates requests using the
@@ -133,64 +133,43 @@ func (h *apiserverProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 //     are passed through to the Kubernetes API.
 //
 // It never returns.
-func runAPIServerProxy(s *tsnet.Server, rt http.RoundTripper, log *zap.SugaredLogger, mode apiServerProxyMode) {
+func runAPIServerProxy(ts *tsnet.Server, rt http.RoundTripper, log *zap.SugaredLogger, mode apiServerProxyMode, host string) {
 	if mode == apiserverProxyModeDisabled {
 		return
 	}
-	ln, err := s.Listen("tcp", ":443")
+	ln, err := ts.Listen("tcp", ":443")
 	if err != nil {
 		log.Fatalf("could not listen on :443: %v", err)
 	}
-	u, err := url.Parse(fmt.Sprintf("https://%s:%s", os.Getenv("KUBERNETES_SERVICE_HOST"), os.Getenv("KUBERNETES_SERVICE_PORT_HTTPS")))
+	u, err := url.Parse(host)
 	if err != nil {
 		log.Fatalf("runAPIServerProxy: failed to parse URL %v", err)
 	}
 
-	lc, err := s.LocalClient()
+	lc, err := ts.LocalClient()
 	if err != nil {
 		log.Fatalf("could not get local client: %v", err)
 	}
+
 	ap := &apiserverProxy{
-		log: log,
-		lc:  lc,
-		rp: &httputil.ReverseProxy{
-			Rewrite: func(r *httputil.ProxyRequest) {
-				// Replace the URL with the Kubernetes APIServer.
-
-				r.Out.URL.Scheme = u.Scheme
-				r.Out.URL.Host = u.Host
-				if mode == apiserverProxyModeNoAuth {
-					// If we are not providing authentication, then we are just
-					// proxying to the Kubernetes API, so we don't need to do
-					// anything else.
-					return
-				}
-
-				// We want to proxy to the Kubernetes API, but we want to use
-				// the caller's identity to do so. We do this by impersonating
-				// the caller using the Kubernetes User Impersonation feature:
-				// https://kubernetes.io/docs/reference/access-authn-authz/authentication/#user-impersonation
-
-				// Out of paranoia, remove all authentication headers that might
-				// have been set by the client.
-				r.Out.Header.Del("Authorization")
-				r.Out.Header.Del("Impersonate-Group")
-				r.Out.Header.Del("Impersonate-User")
-				r.Out.Header.Del("Impersonate-Uid")
-				for k := range r.Out.Header {
-					if strings.HasPrefix(k, "Impersonate-Extra-") {
-						r.Out.Header.Del(k)
-					}
-				}
-
-				// Now add the impersonation headers that we want.
-				if err := addImpersonationHeaders(r.Out, log); err != nil {
-					panic("failed to add impersonation headers: " + err.Error())
-				}
-			},
-			Transport: rt,
-		},
+		log:         log,
+		lc:          lc,
+		mode:        mode,
+		upstreamURL: u,
+		ts:          ts,
 	}
+	ap.rp = &httputil.ReverseProxy{
+		Rewrite: func(pr *httputil.ProxyRequest) {
+			ap.addImpersonationHeadersAsRequired(pr.Out)
+		},
+		Transport: rt,
+	}
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/", ap.serveDefault)
+	mux.HandleFunc("POST /api/v1/namespaces/{namespace}/pods/{pod}/exec", ap.serveExecSPDY)
+	mux.HandleFunc("GET /api/v1/namespaces/{namespace}/pods/{pod}/exec", ap.serveExecWS)
+
 	hs := &http.Server{
 		// Kubernetes uses SPDY for exec and port-forward, however SPDY is
 		// incompatible with HTTP/2; so disable HTTP/2 in the proxy.
@@ -199,14 +178,145 @@ func runAPIServerProxy(s *tsnet.Server, rt http.RoundTripper, log *zap.SugaredLo
 			NextProtos:     []string{"http/1.1"},
 		},
 		TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)),
-		Handler:      ap,
+		Handler:      mux,
 	}
-	log.Infof("listening on %s", ln.Addr())
+	log.Infof("API server proxy in %q mode is listening on %s", mode, ln.Addr())
 	if err := hs.ServeTLS(ln, "", ""); err != nil {
 		log.Fatalf("runAPIServerProxy: failed to serve %v", err)
 	}
 }
 
+// apiserverProxy is an [net/http.Handler] that authenticates requests using the Tailscale
+// LocalAPI and then proxies them to the Kubernetes API.
+type apiserverProxy struct {
+	log *zap.SugaredLogger
+	lc  *tailscale.LocalClient
+	rp  *httputil.ReverseProxy
+
+	mode        apiServerProxyMode
+	ts          *tsnet.Server
+	upstreamURL *url.URL
+}
+
+// serveDefault is the default handler for Kubernetes API server requests.
+func (ap *apiserverProxy) serveDefault(w http.ResponseWriter, r *http.Request) {
+	who, err := ap.whoIs(r)
+	if err != nil {
+		ap.authError(w, err)
+		return
+	}
+	counterNumRequestsProxied.Add(1)
+	ap.rp.ServeHTTP(w, r.WithContext(whoIsKey.WithValue(r.Context(), who)))
+}
+
+// serveExecSPDY serves 'kubectl exec' requests for sessions streamed over SPDY,
+// optionally configuring the kubectl exec sessions to be recorded.
+func (ap *apiserverProxy) serveExecSPDY(w http.ResponseWriter, r *http.Request) {
+	ap.execForProto(w, r, ksr.SPDYProtocol)
+}
+
+// serveExecWS serves 'kubectl exec' requests for sessions streamed over WebSocket,
+// optionally configuring the kubectl exec sessions to be recorded.
+func (ap *apiserverProxy) serveExecWS(w http.ResponseWriter, r *http.Request) {
+	ap.execForProto(w, r, ksr.WSProtocol)
+}
+
+func (ap *apiserverProxy) execForProto(w http.ResponseWriter, r *http.Request, proto ksr.Protocol) {
+	who, err := ap.whoIs(r)
+	if err != nil {
+		ap.authError(w, err)
+		return
+	}
+	counterNumRequestsProxied.Add(1)
+	failOpen, addrs, err := determineRecorderConfig(who)
+	if err != nil {
+		ap.log.Errorf("error trying to determine whether the 'kubectl exec' session needs to be recorded: %v", err)
+		return
+	}
+	if failOpen && len(addrs) == 0 { // will not record
+		ap.rp.ServeHTTP(w, r.WithContext(whoIsKey.WithValue(r.Context(), who)))
+		return
+	}
+	ksr.CounterSessionRecordingsAttempted.Add(1) // at this point we know that users intended for this session to be recorded
+	if !failOpen && len(addrs) == 0 {
+		msg := "forbidden: 'kubectl exec' session must be recorded, but no recorders are available."
+		ap.log.Error(msg)
+		http.Error(w, msg, http.StatusForbidden)
+		return
+	}
+
+	wantsHeader := upgradeHeaderForProto[proto]
+	if h := r.Header.Get("Upgrade"); h != wantsHeader {
+		msg := fmt.Sprintf("[unexpected] unable to verify that streaming protocol is %s, wants Upgrade header %q, got: %q", proto, wantsHeader, h)
+		if failOpen {
+			msg = msg + "; failure mode is 'fail open'; continuing session without recording."
+			ap.log.Warn(msg)
+			ap.rp.ServeHTTP(w, r.WithContext(whoIsKey.WithValue(r.Context(), who)))
+			return
+		}
+		ap.log.Error(msg)
+		msg += "; failure mode is 'fail closed'; closing connection."
+		http.Error(w, msg, http.StatusForbidden)
+		return
+	}
+
+	opts := ksr.HijackerOpts{
+		Req:       r,
+		W:         w,
+		Proto:     proto,
+		TS:        ap.ts,
+		Who:       who,
+		Addrs:     addrs,
+		FailOpen:  failOpen,
+		Pod:       r.PathValue("pod"),
+		Namespace: r.PathValue("namespace"),
+		Log:       ap.log,
+	}
+	h := ksr.New(opts)
+
+	ap.rp.ServeHTTP(h, r.WithContext(whoIsKey.WithValue(r.Context(), who)))
+}
+
+func (h *apiserverProxy) addImpersonationHeadersAsRequired(r *http.Request) {
+	r.URL.Scheme = h.upstreamURL.Scheme
+	r.URL.Host = h.upstreamURL.Host
+	if h.mode == apiserverProxyModeNoAuth {
+		// If we are not providing authentication, then we are just
+		// proxying to the Kubernetes API, so we don't need to do
+		// anything else.
+		return
+	}
+
+	// We want to proxy to the Kubernetes API, but we want to use
+	// the caller's identity to do so. We do this by impersonating
+	// the caller using the Kubernetes User Impersonation feature:
+	// https://kubernetes.io/docs/reference/access-authn-authz/authentication/#user-impersonation
+
+	// Out of paranoia, remove all authentication headers that might
+	// have been set by the client.
+	r.Header.Del("Authorization")
+	r.Header.Del("Impersonate-Group")
+	r.Header.Del("Impersonate-User")
+	r.Header.Del("Impersonate-Uid")
+	for k := range r.Header {
+		if strings.HasPrefix(k, "Impersonate-Extra-") {
+			r.Header.Del(k)
+		}
+	}
+
+	// Now add the impersonation headers that we want.
+	if err := addImpersonationHeaders(r, h.log); err != nil {
+		log.Printf("failed to add impersonation headers: " + err.Error())
+	}
+}
+func (ap *apiserverProxy) whoIs(r *http.Request) (*apitype.WhoIsResponse, error) {
+	return ap.lc.WhoIs(r.Context(), r.RemoteAddr)
+}
+func (ap *apiserverProxy) authError(w http.ResponseWriter, err error) {
+	ap.log.Errorf("failed to authenticate caller: %v", err)
+	http.Error(w, "failed to authenticate caller", http.StatusInternalServerError)
+}
+
 const (
 	// oldCapabilityName is a legacy form of
 	// tailfcg.PeerCapabilityKubernetes capability. The only capability rule
@@ -266,3 +376,39 @@ func addImpersonationHeaders(r *http.Request, log *zap.SugaredLogger) error {
 	}
 	return nil
 }
+
+// determineRecorderConfig determines recorder config from requester's peer
+// capabilities. Determines whether a 'kubectl exec' session from this requester
+// needs to be recorded and what recorders the recording should be sent to.
+func determineRecorderConfig(who *apitype.WhoIsResponse) (failOpen bool, recorderAddresses []netip.AddrPort, _ error) {
+	if who == nil {
+		return false, nil, errors.New("[unexpected] cannot determine caller")
+	}
+	failOpen = true
+	rules, err := tailcfg.UnmarshalCapJSON[tskube.KubernetesCapRule](who.CapMap, tailcfg.PeerCapabilityKubernetes)
+	if err != nil {
+		return failOpen, nil, fmt.Errorf("failed to unmarshal Kubernetes capability: %w", err)
+	}
+	if len(rules) == 0 {
+		return failOpen, nil, nil
+	}
+
+	for _, rule := range rules {
+		if len(rule.RecorderAddrs) != 0 {
+			// TODO (irbekrm): here or later determine if the
+			// recorders behind those addrs are online - else we
+			// spend 30s trying to reach a recorder whose tailscale
+			// status is offline.
+			recorderAddresses = append(recorderAddresses, rule.RecorderAddrs...)
+		}
+		if rule.EnforceRecorder {
+			failOpen = false
+		}
+	}
+	return failOpen, recorderAddresses, nil
+}
+
+var upgradeHeaderForProto = map[ksr.Protocol]string{
+	ksr.SPDYProtocol: "SPDY/3.1",
+	ksr.WSProtocol:   "websocket",
+}

cmd/k8s-operator/proxy_test.go

@@ -7,6 +7,8 @@ package main
 
 import (
 	"net/http"
+	"net/netip"
+	"reflect"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -126,3 +128,72 @@ func TestImpersonationHeaders(t *testing.T) {
 		}
 	}
 }
+
+func Test_determineRecorderConfig(t *testing.T) {
+	addr1, addr2 := netip.MustParseAddrPort("[fd7a:115c:a1e0:ab12:4843:cd96:626b:628b]:80"), netip.MustParseAddrPort("100.99.99.99:80")
+	tests := []struct {
+		name                  string
+		wantFailOpen          bool
+		wantRecorderAddresses []netip.AddrPort
+		who                   *apitype.WhoIsResponse
+	}{
+		{
+			name:                  "two_ips_fail_closed",
+			who:                   whoResp(map[string][]string{string(tailcfg.PeerCapabilityKubernetes): {`{"recorderAddrs":["[fd7a:115c:a1e0:ab12:4843:cd96:626b:628b]:80","100.99.99.99:80"],"enforceRecorder":true}`}}),
+			wantRecorderAddresses: []netip.AddrPort{addr1, addr2},
+		},
+		{
+			name:                  "two_ips_fail_open",
+			who:                   whoResp(map[string][]string{string(tailcfg.PeerCapabilityKubernetes): {`{"recorderAddrs":["[fd7a:115c:a1e0:ab12:4843:cd96:626b:628b]:80","100.99.99.99:80"]}`}}),
+			wantRecorderAddresses: []netip.AddrPort{addr1, addr2},
+			wantFailOpen:          true,
+		},
+		{
+			name:                  "odd_rule_combination_fail_closed",
+			who:                   whoResp(map[string][]string{string(tailcfg.PeerCapabilityKubernetes): {`{"recorderAddrs":["100.99.99.99:80"],"enforceRecorder":false}`, `{"recorderAddrs":["[fd7a:115c:a1e0:ab12:4843:cd96:626b:628b]:80"]}`, `{"enforceRecorder":true,"impersonate":{"groups":["system:masters"]}}`}}),
+			wantRecorderAddresses: []netip.AddrPort{addr2, addr1},
+		},
+		{
+			name:         "no_caps",
+			who:          whoResp(map[string][]string{}),
+			wantFailOpen: true,
+		},
+		{
+			name:         "no_recorder_caps",
+			who:          whoResp(map[string][]string{"foo": {`{"x":"y"}`}, string(tailcfg.PeerCapabilityKubernetes): {`{"impersonate":{"groups":["system:masters"]}}`}}),
+			wantFailOpen: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotFailOpen, gotRecorderAddresses, err := determineRecorderConfig(tt.who)
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if gotFailOpen != tt.wantFailOpen {
+				t.Errorf("determineRecorderConfig() gotFailOpen = %v, want %v", gotFailOpen, tt.wantFailOpen)
+			}
+			if !reflect.DeepEqual(gotRecorderAddresses, tt.wantRecorderAddresses) {
+				t.Errorf("determineRecorderConfig() gotRecorderAddresses = %v, want %v", gotRecorderAddresses, tt.wantRecorderAddresses)
+			}
+		})
+	}
+}
+
+func whoResp(capMap map[string][]string) *apitype.WhoIsResponse {
+	resp := &apitype.WhoIsResponse{
+		CapMap: tailcfg.PeerCapMap{},
+	}
+	for cap, rules := range capMap {
+		resp.CapMap[tailcfg.PeerCapability(cap)] = raw(rules...)
+	}
+	return resp
+}
+
+func raw(in ...string) []tailcfg.RawMessage {
+	var out []tailcfg.RawMessage
+	for _, i := range in {
+		out = append(out, tailcfg.RawMessage(i))
+	}
+	return out
+}

cmd/k8s-operator/proxyclass.go

@@ -8,7 +8,9 @@ package main
 import (
 	"context"
 	"fmt"
+	"slices"
 	"strings"
+	"sync"
 
 	dockerref "github.com/distribution/reference"
 	"go.uber.org/zap"
@@ -18,6 +20,7 @@ import (
 	apivalidation "k8s.io/apimachinery/pkg/api/validation"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	metavalidation "k8s.io/apimachinery/pkg/apis/meta/v1/validation"
+	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	"k8s.io/client-go/tools/record"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -25,6 +28,8 @@ import (
 	tsoperator "tailscale.com/k8s-operator"
 	tsapi "tailscale.com/k8s-operator/apis/v1alpha1"
 	"tailscale.com/tstime"
+	"tailscale.com/util/clientmetric"
+	"tailscale.com/util/set"
 )
 
 const (
@@ -41,8 +46,20 @@ type ProxyClassReconciler struct {
 	recorder record.EventRecorder
 	logger   *zap.SugaredLogger
 	clock    tstime.Clock
+
+	mu sync.Mutex // protects following
+
+	// managedProxyClasses is a set of all ProxyClass resources that we're currently
+	// managing. This is only used for metrics.
+	managedProxyClasses set.Slice[types.UID]
 }
 
+var (
+	// gaugeProxyClassResources tracks the number of ProxyClass resources
+	// that we're currently managing.
+	gaugeProxyClassResources = clientmetric.NewGauge("k8s_proxyclass_resources")
+)
+
 func (pcr *ProxyClassReconciler) Reconcile(ctx context.Context, req reconcile.Request) (res reconcile.Result, err error) {
 	logger := pcr.logger.With("ProxyClass", req.Name)
 	logger.Debugf("starting reconcile")
@@ -57,9 +74,26 @@ func (pcr *ProxyClassReconciler) Reconcile(ctx context.Context, req reconcile.Re
 		return reconcile.Result{}, fmt.Errorf("failed to get tailscale.com ProxyClass: %w", err)
 	}
 	if !pc.DeletionTimestamp.IsZero() {
-		logger.Debugf("ProxyClass is being deleted, do nothing")
-		return reconcile.Result{}, nil
+		logger.Debugf("ProxyClass is being deleted")
+		return reconcile.Result{}, pcr.maybeCleanup(ctx, logger, pc)
 	}
+
+	// Add a finalizer so that we can ensure that metrics get updated when
+	// this ProxyClass is deleted.
+	if !slices.Contains(pc.Finalizers, FinalizerName) {
+		logger.Debugf("updating ProxyClass finalizers")
+		pc.Finalizers = append(pc.Finalizers, FinalizerName)
+		if err := pcr.Update(ctx, pc); err != nil {
+			return res, fmt.Errorf("failed to add finalizer: %w", err)
+		}
+	}
+
+	// Ensure this ProxyClass is tracked in metrics.
+	pcr.mu.Lock()
+	pcr.managedProxyClasses.Add(pc.UID)
+	gaugeProxyClassResources.Set(int64(pcr.managedProxyClasses.Len()))
+	pcr.mu.Unlock()
+
 	oldPCStatus := pc.Status.DeepCopy()
 	if errs := pcr.validate(pc); errs != nil {
 		msg := fmt.Sprintf(messageProxyClassInvalid, errs.ToAggregate().Error())
@@ -77,7 +111,7 @@ func (pcr *ProxyClassReconciler) Reconcile(ctx context.Context, req reconcile.Re
 	return reconcile.Result{}, nil
 }
 
-func (a *ProxyClassReconciler) validate(pc *tsapi.ProxyClass) (violations field.ErrorList) {
+func (pcr *ProxyClassReconciler) validate(pc *tsapi.ProxyClass) (violations field.ErrorList) {
 	if sts := pc.Spec.StatefulSet; sts != nil {
 		if len(sts.Labels) > 0 {
 			if errs := metavalidation.ValidateLabels(sts.Labels, field.NewPath(".spec.statefulSet.labels")); errs != nil {
@@ -103,13 +137,13 @@ func (a *ProxyClassReconciler) validate(pc *tsapi.ProxyClass) (violations field.
 			if tc := pod.TailscaleContainer; tc != nil {
 				for _, e := range tc.Env {
 					if strings.HasPrefix(string(e.Name), "TS_") {
-						a.recorder.Event(pc, corev1.EventTypeWarning, reasonCustomTSEnvVar, fmt.Sprintf(messageCustomTSEnvVar, string(e.Name), "tailscale"))
+						pcr.recorder.Event(pc, corev1.EventTypeWarning, reasonCustomTSEnvVar, fmt.Sprintf(messageCustomTSEnvVar, string(e.Name), "tailscale"))
 					}
 					if strings.EqualFold(string(e.Name), "EXPERIMENTAL_TS_CONFIGFILE_PATH") {
-						a.recorder.Event(pc, corev1.EventTypeWarning, reasonCustomTSEnvVar, fmt.Sprintf(messageCustomTSEnvVar, string(e.Name), "tailscale"))
+						pcr.recorder.Event(pc, corev1.EventTypeWarning, reasonCustomTSEnvVar, fmt.Sprintf(messageCustomTSEnvVar, string(e.Name), "tailscale"))
 					}
 					if strings.EqualFold(string(e.Name), "EXPERIMENTAL_ALLOW_PROXYING_CLUSTER_TRAFFIC_VIA_INGRESS") {
-						a.recorder.Event(pc, corev1.EventTypeWarning, reasonCustomTSEnvVar, fmt.Sprintf(messageCustomTSEnvVar, string(e.Name), "tailscale"))
+						pcr.recorder.Event(pc, corev1.EventTypeWarning, reasonCustomTSEnvVar, fmt.Sprintf(messageCustomTSEnvVar, string(e.Name), "tailscale"))
 					}
 				}
 				if tc.Image != "" {
@@ -135,3 +169,27 @@ func (a *ProxyClassReconciler) validate(pc *tsapi.ProxyClass) (violations field.
 	// time.
 	return violations
 }
+
+// maybeCleanup removes tailscale.com finalizer and ensures that the ProxyClass
+// is no longer counted towards k8s_proxyclass_resources.
+func (pcr *ProxyClassReconciler) maybeCleanup(ctx context.Context, logger *zap.SugaredLogger, pc *tsapi.ProxyClass) error {
+	ix := slices.Index(pc.Finalizers, FinalizerName)
+	if ix < 0 {
+		logger.Debugf("no finalizer, nothing to do")
+		pcr.mu.Lock()
+		defer pcr.mu.Unlock()
+		pcr.managedProxyClasses.Remove(pc.UID)
+		gaugeProxyClassResources.Set(int64(pcr.managedProxyClasses.Len()))
+		return nil
+	}
+	pc.Finalizers = append(pc.Finalizers[:ix], pc.Finalizers[ix+1:]...)
+	if err := pcr.Update(ctx, pc); err != nil {
+		return fmt.Errorf("failed to remove finalizer: %w", err)
+	}
+	pcr.mu.Lock()
+	defer pcr.mu.Unlock()
+	pcr.managedProxyClasses.Remove(pc.UID)
+	gaugeProxyClassResources.Set(int64(pcr.managedProxyClasses.Len()))
+	logger.Infof("ProxyClass resources have been cleaned up")
+	return nil
+}

cmd/k8s-operator/proxyclass_test.go

@@ -29,7 +29,8 @@ func TestProxyClass(t *testing.T) {
 			// The apiserver is supposed to set the UID, but the fake client
 			// doesn't. So, set it explicitly because other code later depends
 			// on it being set.
-			UID: types.UID("1234-UID"),
+			UID:        types.UID("1234-UID"),
+			Finalizers: []string{"tailscale.com/finalizer"},
 		},
 		Spec: tsapi.ProxyClassSpec{
 			StatefulSet: &tsapi.StatefulSet{

cmd/k8s-operator/sts.go

@@ -294,6 +294,7 @@ func (a *tailscaleSTSReconciler) reconcileHeadlessService(ctx context.Context, l
 			Selector: map[string]string{
 				"app": sts.ParentResourceUID,
 			},
+			IPFamilyPolicy: ptr.To(corev1.IPFamilyPolicyPreferDualStack),
 		},
 	}
 	logger.Debugf("reconciling headless service for StatefulSet")

cmd/k8s-operator/svc.go

@@ -62,6 +62,8 @@ type ServiceReconciler struct {
 	tsNamespace string
 
 	clock tstime.Clock
+
+	proxyDefaultClass string
 }
 
 var (
@@ -208,7 +210,7 @@ func (a *ServiceReconciler) maybeProvision(ctx context.Context, logger *zap.Suga
 		return nil
 	}
 
-	proxyClass := proxyClassForObject(svc)
+	proxyClass := proxyClassForObject(svc, a.proxyDefaultClass)
 	if proxyClass != "" {
 		if ready, err := proxyClassIsReady(ctx, proxyClass, a.Client); err != nil {
 			errMsg := fmt.Errorf("error verifying ProxyClass for Service: %w", err)
@@ -404,8 +406,14 @@ func tailnetTargetAnnotation(svc *corev1.Service) string {
 	return svc.Annotations[annotationTailnetTargetIPOld]
 }
 
-func proxyClassForObject(o client.Object) string {
-	return o.GetLabels()[LabelProxyClass]
+// proxyClassForObject returns the proxy class for the given object. If the
+// object does not have a proxy class label, it returns the default proxy class
+func proxyClassForObject(o client.Object, proxyDefaultClass string) string {
+	proxyClass, exists := o.GetLabels()[LabelProxyClass]
+	if !exists {
+		proxyClass = proxyDefaultClass
+	}
+	return proxyClass
 }
 
 func proxyClassIsReady(ctx context.Context, name string, cl client.Client) (bool, error) {

cmd/k8s-operator/testutils_test.go

@@ -319,7 +319,8 @@ func expectedHeadlessService(name string, parentType string) *corev1.Service {
 			Selector: map[string]string{
 				"app": "1234-UID",
 			},
-			ClusterIP: "None",
+			ClusterIP:      "None",
+			IPFamilyPolicy: ptr.To(corev1.IPFamilyPolicyPreferDualStack),
 		},
 	}
 }

cmd/natc/natc.go

@@ -448,7 +448,7 @@ func (c *connector) handleTCPFlow(src, dst netip.AddrPort) (handler func(net.Con
 // in --ignore-destinations
 func (c *connector) ignoreDestination(dstAddrs []netip.Addr) bool {
 	for _, a := range dstAddrs {
-		if _, ok := c.ignoreDsts.Get(a); ok {
+		if _, ok := c.ignoreDsts.Lookup(a); ok {
 			return true
 		}
 	}
@@ -489,7 +489,7 @@ type perPeerState struct {
 func (ps *perPeerState) domainForIP(ip netip.Addr) (_ string, ok bool) {
 	ps.mu.Lock()
 	defer ps.mu.Unlock()
-	return ps.addrToDomain.Get(ip)
+	return ps.addrToDomain.Lookup(ip)
 }
 
 // ipForDomain assigns a pair of unique IP addresses for the given domain and
@@ -515,7 +515,7 @@ func (ps *perPeerState) ipForDomain(domain string) ([]netip.Addr, error) {
 // domain.
 // ps.mu must be held.
 func (ps *perPeerState) isIPUsedLocked(ip netip.Addr) bool {
-	_, ok := ps.addrToDomain.Get(ip)
+	_, ok := ps.addrToDomain.Lookup(ip)
 	return ok
 }
 

cmd/stund/depaware.txt

@@ -2,6 +2,12 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
 
         github.com/beorn7/perks/quantile                             from github.com/prometheus/client_golang/prometheus
      💣 github.com/cespare/xxhash/v2                                 from github.com/prometheus/client_golang/prometheus
+        github.com/go-json-experiment/json                           from tailscale.com/types/opt
+        github.com/go-json-experiment/json/internal                  from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonflags        from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonopts         from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonwire         from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/jsontext                  from github.com/go-json-experiment/json+
         github.com/google/uuid                                       from tailscale.com/util/fastuuid
      💣 github.com/prometheus/client_golang/prometheus               from tailscale.com/tsweb/promvarz
         github.com/prometheus/client_golang/prometheus/internal      from github.com/prometheus/client_golang/prometheus
@@ -59,7 +65,7 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         tailscale.com/types/lazy                                     from tailscale.com/version+
         tailscale.com/types/logger                                   from tailscale.com/tsweb
         tailscale.com/types/opt                                      from tailscale.com/envknob+
-        tailscale.com/types/ptr                                      from tailscale.com/tailcfg
+        tailscale.com/types/ptr                                      from tailscale.com/tailcfg+
         tailscale.com/types/structs                                  from tailscale.com/tailcfg+
         tailscale.com/types/tkatype                                  from tailscale.com/tailcfg+
         tailscale.com/types/views                                    from tailscale.com/net/tsaddr+
@@ -128,6 +134,7 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         embed                                                        from crypto/internal/nistec+
         encoding                                                     from encoding/json+
         encoding/asn1                                                from crypto/x509+
+        encoding/base32                                              from github.com/go-json-experiment/json
         encoding/base64                                              from encoding/json+
         encoding/binary                                              from compress/gzip+
         encoding/hex                                                 from crypto/x509+

cmd/stunstamp/api.go

@@ -1,142 +0,0 @@
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-
-package main
-
-import (
-	"compress/gzip"
-	"encoding/json"
-	"errors"
-	"net/http"
-	"net/url"
-	"strconv"
-	"strings"
-	"time"
-
-	sq "github.com/Masterminds/squirrel"
-)
-
-type api struct {
-	db  *db
-	mux *http.ServeMux
-}
-
-func newAPI(db *db) *api {
-	a := &api{
-		db: db,
-	}
-	mux := http.NewServeMux()
-	mux.HandleFunc("/query", a.query)
-	a.mux = mux
-	return a
-}
-
-type apiResult struct {
-	At         int    `json:"at"` // time.Time.Unix()
-	RegionID   int    `json:"regionID"`
-	Hostname   string `json:"hostname"`
-	Af         int    `json:"af"` // 4 or 6
-	Addr       string `json:"addr"`
-	Source     int    `json:"source"` // timestampSourceUserspace (0) or timestampSourceKernel (1)
-	StableConn bool   `json:"stableConn"`
-	DstPort    int    `json:"dstPort"`
-	RttNS      *int   `json:"rttNS"`
-}
-
-func getTimeBounds(vals url.Values) (from time.Time, to time.Time, err error) {
-	lastForm, ok := vals["last"]
-	if ok && len(lastForm) > 0 {
-		dur, err := time.ParseDuration(lastForm[0])
-		if err != nil {
-			return time.Time{}, time.Time{}, err
-		}
-		now := time.Now()
-		return now.Add(-dur), now, nil
-	}
-
-	fromForm, ok := vals["from"]
-	if ok && len(fromForm) > 0 {
-		fromUnixSec, err := strconv.Atoi(fromForm[0])
-		if err != nil {
-			return time.Time{}, time.Time{}, err
-		}
-		from = time.Unix(int64(fromUnixSec), 0)
-		toForm, ok := vals["to"]
-		if ok && len(toForm) > 0 {
-			toUnixSec, err := strconv.Atoi(toForm[0])
-			if err != nil {
-				return time.Time{}, time.Time{}, err
-			}
-			to = time.Unix(int64(toUnixSec), 0)
-		} else {
-			return time.Time{}, time.Time{}, errors.New("from specified without to")
-		}
-		return from, to, nil
-	}
-
-	// no time bounds specified, default to last 1h
-	now := time.Now()
-	return now.Add(-time.Hour), now, nil
-}
-
-func (a *api) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	a.mux.ServeHTTP(w, r)
-}
-
-func (a *api) query(w http.ResponseWriter, r *http.Request) {
-	err := r.ParseForm()
-	if err != nil {
-		http.Error(w, err.Error(), 500)
-		return
-	}
-	from, to, err := getTimeBounds(r.Form)
-	if err != nil {
-		http.Error(w, err.Error(), 500)
-		return
-	}
-
-	sb := sq.Select("at_unix", "region_id", "hostname", "af", "address", "timestamp_source", "stable_conn", "dst_port", "rtt_ns").From("rtt")
-	sb = sb.Where(sq.And{
-		sq.GtOrEq{"at_unix": from.Unix()},
-		sq.LtOrEq{"at_unix": to.Unix()},
-	})
-	query, args, err := sb.ToSql()
-	if err != nil {
-		return
-	}
-
-	rows, err := a.db.Query(query, args...)
-	if err != nil {
-		http.Error(w, err.Error(), 500)
-		return
-	}
-	results := make([]apiResult, 0)
-	for rows.Next() {
-		rtt := 0
-		result := apiResult{
-			RttNS: &rtt,
-		}
-		err = rows.Scan(&result.At, &result.RegionID, &result.Hostname, &result.Af, &result.Addr, &result.Source, &result.StableConn, &result.DstPort, &result.RttNS)
-		if err != nil {
-			http.Error(w, err.Error(), 500)
-			return
-		}
-		results = append(results, result)
-	}
-	if rows.Err() != nil {
-		http.Error(w, rows.Err().Error(), 500)
-		return
-	}
-	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
-		gz := gzip.NewWriter(w)
-		defer gz.Close()
-		w.Header().Set("Content-Encoding", "gzip")
-		err = json.NewEncoder(gz).Encode(&results)
-	} else {
-		err = json.NewEncoder(w).Encode(&results)
-	}
-	if err != nil {
-		http.Error(w, err.Error(), 500)
-		return
-	}
-}

cmd/stunstamp/stunstamp.go

@@ -1,13 +1,14 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-// The stunstamp binary measures STUN round-trip latency with DERPs.
+// The stunstamp binary measures round-trip latency with DERPs.
 package main
 
 import (
 	"bytes"
 	"cmp"
 	"context"
+	"crypto/tls"
 	"encoding/json"
 	"errors"
 	"flag"
@@ -22,6 +23,7 @@ import (
 	"net/url"
 	"os"
 	"os/signal"
+	"runtime"
 	"slices"
 	"strconv"
 	"strings"
@@ -31,21 +33,23 @@ import (
 
 	"github.com/golang/snappy"
 	"github.com/prometheus/prometheus/prompb"
+	"github.com/tcnksm/go-httpstat"
 	"tailscale.com/logtail/backoff"
 	"tailscale.com/net/stun"
+	"tailscale.com/net/tcpinfo"
 	"tailscale.com/tailcfg"
 )
 
 var (
 	flagDERPMap        = flag.String("derp-map", "https://login.tailscale.com/derpmap/default", "URL to DERP map")
-	flagOut            = flag.String("out", "", "output sqlite filename")
 	flagInterval       = flag.Duration("interval", time.Minute, "interval to probe at in time.ParseDuration() format")
-	flagAPI            = flag.String("api", "", "listen addr for HTTP API")
 	flagIPv6           = flag.Bool("ipv6", false, "probe IPv6 addresses")
-	flagRetention      = flag.Duration("retention", time.Hour*24*7, "sqlite retention period in time.ParseDuration() format")
 	flagRemoteWriteURL = flag.String("rw-url", "", "prometheus remote write URL")
 	flagInstance       = flag.String("instance", "", "instance label value; defaults to hostname if unspecified")
-	flagDstPorts       = flag.String("dst-ports", "", "comma-separated list of destination ports to monitor")
+	flagSTUNDstPorts   = flag.String("stun-dst-ports", "", "comma-separated list of STUN destination ports to monitor")
+	flagHTTPSDstPorts  = flag.String("https-dst-ports", "", "comma-separated list of HTTPS destination ports to monitor")
+	flagTCPDstPorts    = flag.String("tcp-dst-ports", "", "comma-separated list of TCP destination ports to monitor")
+	flagICMP           = flag.Bool("icmp", false, "probe ICMP")
 )
 
 const (
@@ -63,10 +67,13 @@ func getDERPMap(ctx context.Context, url string) (*tailcfg.DERPMap, error) {
 		return nil, err
 	}
 	defer resp.Body.Close()
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("non-200 derp map resp: %d", resp.StatusCode)
+	}
 	dm := tailcfg.DERPMap{}
 	err = json.NewDecoder(resp.Body).Decode(&dm)
 	if err != nil {
-		return nil, nil
+		return nil, fmt.Errorf("failed to decode derp map resp: %v", err)
 	}
 	return &dm, nil
 }
@@ -89,12 +96,22 @@ func (t timestampSource) String() string {
 	}
 }
 
+type protocol string
+
+const (
+	protocolSTUN  protocol = "stun"
+	protocolICMP  protocol = "icmp"
+	protocolHTTPS protocol = "https"
+	protocolTCP   protocol = "tcp"
+)
+
 // resultKey contains the stable dimensions and their values for a given
 // timeseries, i.e. not time and not rtt/timeout.
 type resultKey struct {
 	meta            nodeMeta
 	timestampSource timestampSource
 	connStability   connStability
+	protocol        protocol
 	dstPort         int
 }
 
@@ -104,7 +121,203 @@ type result struct {
 	rtt *time.Duration // nil signifies failure, e.g. timeout
 }
 
-func measureRTT(conn io.ReadWriteCloser, dst *net.UDPAddr) (rtt time.Duration, err error) {
+type lportsPool struct {
+	sync.Mutex
+	ports []int
+}
+
+func (l *lportsPool) get() int {
+	l.Lock()
+	defer l.Unlock()
+	ret := l.ports[0]
+	l.ports = append(l.ports[:0], l.ports[1:]...)
+	return ret
+}
+
+func (l *lportsPool) put(i int) {
+	l.Lock()
+	defer l.Unlock()
+	l.ports = append(l.ports, int(i))
+}
+
+var (
+	lports *lportsPool
+)
+
+const (
+	lportPoolSize = 16000
+	lportBase     = 2048
+)
+
+func init() {
+	lports = &lportsPool{
+		ports: make([]int, 0, lportPoolSize),
+	}
+	for i := lportBase; i < lportBase+lportPoolSize; i++ {
+		lports.ports = append(lports.ports, i)
+	}
+}
+
+// lportForTCPConn satisfies io.ReadWriteCloser, but is really just used to pass
+// around a persistent laddr for stableConn purposes. The underlying TCP
+// connection is not created until measurement time as in some cases we need to
+// measure dial time.
+type lportForTCPConn int
+
+func (l *lportForTCPConn) Close() error {
+	if *l == 0 {
+		return nil
+	}
+	lports.put(int(*l))
+	return nil
+}
+
+func (l *lportForTCPConn) Write([]byte) (int, error) {
+	return 0, errors.New("unimplemented")
+}
+
+func (l *lportForTCPConn) Read([]byte) (int, error) {
+	return 0, errors.New("unimplemented")
+}
+
+func addrInUse(err error, lport *lportForTCPConn) bool {
+	if errors.Is(err, syscall.EADDRINUSE) {
+		old := int(*lport)
+		// abandon port, don't return it to pool
+		*lport = lportForTCPConn(lports.get()) // get a new port
+		log.Printf("EADDRINUSE: %v old: %d new: %d", err, old, *lport)
+		return true
+	}
+	return false
+}
+
+func tcpDial(ctx context.Context, lport *lportForTCPConn, dst netip.AddrPort) (net.Conn, error) {
+	for {
+		var opErr error
+		dialer := &net.Dialer{
+			LocalAddr: &net.TCPAddr{
+				Port: int(*lport),
+			},
+			Control: func(network, address string, c syscall.RawConn) error {
+				return c.Control(func(fd uintptr) {
+					// we may restart faster than TIME_WAIT can clear
+					opErr = setSOReuseAddr(fd)
+				})
+			},
+		}
+		if opErr != nil {
+			panic(opErr)
+		}
+		tcpConn, err := dialer.DialContext(ctx, "tcp", dst.String())
+		if err != nil {
+			if addrInUse(err, lport) {
+				continue
+			}
+			return nil, err
+		}
+		return tcpConn, nil
+	}
+}
+
+type tempError struct {
+	error
+}
+
+func (t tempError) Temporary() bool {
+	return true
+}
+
+func measureTCPRTT(conn io.ReadWriteCloser, _ string, dst netip.AddrPort) (rtt time.Duration, err error) {
+	lport, ok := conn.(*lportForTCPConn)
+	if !ok {
+		return 0, fmt.Errorf("unexpected conn type: %T", conn)
+	}
+	// Set a dial timeout < 1s (TCP_TIMEOUT_INIT on Linux) as a means to avoid
+	// SYN retries, which can contribute to tcpi->rtt below. This simply limits
+	// retries from the initiator, but SYN+ACK on the reverse path can also
+	// time out and be retransmitted.
+	ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*750)
+	defer cancel()
+	tcpConn, err := tcpDial(ctx, lport, dst)
+	if err != nil {
+		return 0, tempError{err}
+	}
+	defer tcpConn.Close()
+	// This is an unreliable method to measure TCP RTT. The Linux kernel
+	// describes it as such in tcp_rtt_estimator(). We take some care in how we
+	// hold tcp_info->rtt here, e.g. clamping dial timeout, but if we are to
+	// actually use this elsewhere as an input to some decision it warrants a
+	// deeper study and consideration for alternative methods. Its usefulness
+	// here is as a point of comparison against the other methods.
+	rtt, err = tcpinfo.RTT(tcpConn)
+	if err != nil {
+		return 0, tempError{err}
+	}
+	return rtt, nil
+}
+
+func measureHTTPSRTT(conn io.ReadWriteCloser, hostname string, dst netip.AddrPort) (rtt time.Duration, err error) {
+	lport, ok := conn.(*lportForTCPConn)
+	if !ok {
+		return 0, fmt.Errorf("unexpected conn type: %T", conn)
+	}
+	var httpResult httpstat.Result
+	// 5s mirrors net/netcheck.overallProbeTimeout used in net/netcheck.Client.measureHTTPSLatency.
+	reqCtx, cancel := context.WithTimeout(httpstat.WithHTTPStat(context.Background(), &httpResult), time.Second*5)
+	defer cancel()
+	reqURL := "https://" + dst.String() + "/derp/latency-check"
+	req, err := http.NewRequestWithContext(reqCtx, "GET", reqURL, nil)
+	if err != nil {
+		return 0, err
+	}
+	client := &http.Client{}
+	// 1.5s mirrors derp/derphttp.dialnodeTimeout used in derp/derphttp.DialNode().
+	dialCtx, dialCancel := context.WithTimeout(reqCtx, time.Millisecond*1500)
+	defer dialCancel()
+	tcpConn, err := tcpDial(dialCtx, lport, dst)
+	if err != nil {
+		return 0, tempError{err}
+	}
+	defer tcpConn.Close()
+	tlsConn := tls.Client(tcpConn, &tls.Config{
+		ServerName: hostname,
+	})
+	// Mirror client/netcheck behavior, which handshakes before handing the
+	// tlsConn over to the http.Client via http.Transport
+	err = tlsConn.Handshake()
+	if err != nil {
+		return 0, tempError{err}
+	}
+	tlsConnCh := make(chan net.Conn, 1)
+	tlsConnCh <- tlsConn
+	tr := &http.Transport{
+		DialTLSContext: func(ctx context.Context, network string, addr string) (net.Conn, error) {
+			select {
+			case tlsConn := <-tlsConnCh:
+				return tlsConn, nil
+			default:
+				return nil, errors.New("unexpected second call of DialTLSContext")
+			}
+		},
+	}
+	client.Transport = tr
+	resp, err := client.Do(req)
+	if err != nil {
+		return 0, tempError{err}
+	}
+	if resp.StatusCode/100 != 2 {
+		return 0, tempError{fmt.Errorf("unexpected status code: %d", resp.StatusCode)}
+	}
+	defer resp.Body.Close()
+	_, err = io.Copy(io.Discard, io.LimitReader(resp.Body, 8<<10))
+	if err != nil {
+		return 0, tempError{err}
+	}
+	httpResult.End(time.Now())
+	return httpResult.ServerProcessing, nil
+}
+
+func measureSTUNRTT(conn io.ReadWriteCloser, _ string, dst netip.AddrPort) (rtt time.Duration, err error) {
 	uconn, ok := conn.(*net.UDPConn)
 	if !ok {
 		return 0, fmt.Errorf("unexpected conn type: %T", conn)
@@ -116,7 +329,10 @@ func measureRTT(conn io.ReadWriteCloser, dst *net.UDPAddr) (rtt time.Duration, e
 	txID := stun.NewTxID()
 	req := stun.Request(txID)
 	txAt := time.Now()
-	_, err = uconn.WriteToUDP(req, dst)
+	_, err = uconn.WriteToUDP(req, &net.UDPAddr{
+		IP:   dst.Addr().AsSlice(),
+		Port: int(dst.Port()),
+	})
 	if err != nil {
 		return 0, fmt.Errorf("error writing to udp socket: %w", err)
 	}
@@ -153,20 +369,19 @@ type nodeMeta struct {
 	addr       netip.Addr
 }
 
-type measureFn func(conn io.ReadWriteCloser, dst *net.UDPAddr) (rtt time.Duration, err error)
+type measureFn func(conn io.ReadWriteCloser, hostname string, dst netip.AddrPort) (rtt time.Duration, err error)
 
-// probe measures STUN round trip time for the node described by meta over
-// conn against dstPort. It may return a nil duration and nil error if the
-// STUN request timed out. A non-nil error indicates an unrecoverable or
-// non-temporary error.
-func probe(meta nodeMeta, conn io.ReadWriteCloser, fn measureFn, dstPort int) (*time.Duration, error) {
+// probe measures round trip time for the node described by meta over cf against
+// dstPort. It may return a nil duration and nil error in the event of a
+// timeout. A non-nil error indicates an unrecoverable or non-temporary error.
+func probe(meta nodeMeta, cf *connAndMeasureFn, dstPort int) (*time.Duration, error) {
 	ua := &net.UDPAddr{
 		IP:   net.IP(meta.addr.AsSlice()),
 		Port: dstPort,
 	}
 
 	time.Sleep(rand.N(200 * time.Millisecond)) // jitter across tx
-	rtt, err := fn(conn, ua)
+	rtt, err := cf.fn(cf.conn, meta.hostname, netip.AddrPortFrom(meta.addr, uint16(dstPort)))
 	if err != nil {
 		if isTemporaryOrTimeoutErr(err) {
 			log.Printf("temp error measuring RTT to %s(%s): %v", meta.hostname, ua.String(), err)
@@ -237,43 +452,138 @@ func nodeMetaFromDERPMap(dm *tailcfg.DERPMap, nodeMetaByAddr map[netip.Addr]node
 	return stale, nil
 }
 
-func getStableConns(stableConns map[netip.Addr]map[int][2]io.ReadWriteCloser, addr netip.Addr, dstPort int) ([2]io.ReadWriteCloser, error) {
-	conns := [2]io.ReadWriteCloser{}
-	byDstPort, ok := stableConns[addr]
-	if ok {
-		conns, ok = byDstPort[dstPort]
-		if ok {
-			return conns, nil
-		}
-	}
-	if supportsKernelTS() {
-		kconn, err := getConnKernelTimestamp()
-		if err != nil {
-			return conns, err
-		}
-		conns[timestampSourceKernel] = kconn
-	}
-	uconn, err := net.ListenUDP("udp", &net.UDPAddr{})
-	if err != nil {
-		if supportsKernelTS() {
-			conns[timestampSourceKernel].Close()
-		}
-		return conns, err
-	}
-	conns[timestampSourceUserspace] = uconn
-	if byDstPort == nil {
-		byDstPort = make(map[int][2]io.ReadWriteCloser)
-	}
-	byDstPort[dstPort] = conns
-	stableConns[addr] = byDstPort
-	return conns, nil
+type connAndMeasureFn struct {
+	conn io.ReadWriteCloser
+	fn   measureFn
 }
 
-// probeNodes measures the round-trip time for STUN binding requests against the
-// DERP nodes described by nodeMetaByAddr while using/updating stableConns for
-// UDP sockets that should be recycled across runs. It returns the results or
-// an error if one occurs.
-func probeNodes(nodeMetaByAddr map[netip.Addr]nodeMeta, stableConns map[netip.Addr]map[int][2]io.ReadWriteCloser, dstPorts []int) ([]result, error) {
+// newConnAndMeasureFn returns a connAndMeasureFn or an error. It may return
+// nil for both if some combination of the supplied timestampSource, protocol,
+// or connStability is unsupported.
+func newConnAndMeasureFn(source timestampSource, protocol protocol, stable connStability) (*connAndMeasureFn, error) {
+	info := getProtocolSupportInfo(protocol)
+	if !info.stableConn && bool(stable) {
+		return nil, nil
+	}
+	if !info.userspaceTS && source == timestampSourceUserspace {
+		return nil, nil
+	}
+	if !info.kernelTS && source == timestampSourceKernel {
+		return nil, nil
+	}
+	switch protocol {
+	case protocolSTUN:
+		if source == timestampSourceKernel {
+			conn, err := getUDPConnKernelTimestamp()
+			if err != nil {
+				return nil, err
+			}
+			return &connAndMeasureFn{
+				conn: conn,
+				fn:   measureSTUNRTTKernel,
+			}, nil
+		} else {
+			conn, err := net.ListenUDP("udp", &net.UDPAddr{})
+			if err != nil {
+				return nil, err
+			}
+			return &connAndMeasureFn{
+				conn: conn,
+				fn:   measureSTUNRTT,
+			}, nil
+		}
+	case protocolICMP:
+		// TODO(jwhited): implement
+		return nil, nil
+	case protocolHTTPS:
+		localPort := 0
+		if stable {
+			localPort = lports.get()
+		}
+		conn := lportForTCPConn(localPort)
+		return &connAndMeasureFn{
+			conn: &conn,
+			fn:   measureHTTPSRTT,
+		}, nil
+	case protocolTCP:
+		localPort := 0
+		if stable {
+			localPort = lports.get()
+		}
+		conn := lportForTCPConn(localPort)
+		return &connAndMeasureFn{
+			conn: &conn,
+			fn:   measureTCPRTT,
+		}, nil
+	}
+	return nil, errors.New("unknown protocol")
+}
+
+type stableConnKey struct {
+	node     netip.Addr
+	protocol protocol
+	port     int
+}
+
+type protocolSupportInfo struct {
+	kernelTS    bool
+	userspaceTS bool
+	stableConn  bool
+}
+
+func getConns(
+	stableConns map[stableConnKey][2]*connAndMeasureFn,
+	addr netip.Addr,
+	protocol protocol,
+	dstPort int,
+) (stable, unstable [2]*connAndMeasureFn, err error) {
+	key := stableConnKey{addr, protocol, dstPort}
+	defer func() {
+		if err != nil {
+			for _, source := range []timestampSource{timestampSourceUserspace, timestampSourceKernel} {
+				c := stable[source]
+				if c != nil {
+					c.conn.Close()
+				}
+				c = unstable[source]
+				if c != nil {
+					c.conn.Close()
+				}
+			}
+		}
+	}()
+
+	var ok bool
+	stable, ok = stableConns[key]
+	if !ok {
+		for _, source := range []timestampSource{timestampSourceUserspace, timestampSourceKernel} {
+			var cf *connAndMeasureFn
+			cf, err = newConnAndMeasureFn(source, protocol, stableConn)
+			if err != nil {
+				return
+			}
+			stable[source] = cf
+		}
+		stableConns[key] = stable
+	}
+
+	for _, source := range []timestampSource{timestampSourceUserspace, timestampSourceKernel} {
+		var cf *connAndMeasureFn
+		cf, err = newConnAndMeasureFn(source, protocol, unstableConn)
+		if err != nil {
+			return
+		}
+		unstable[source] = cf
+	}
+	return stable, unstable, nil
+}
+
+// probeNodes measures the round-trip time for the protocols and ports described
+// by portsByProtocol against the DERP nodes described by nodeMetaByAddr.
+// stableConns are used to recycle connections across calls to probeNodes.
+// probeNodes is also responsible for trimming stableConns based on node
+// lifetime in nodeMetaByAddr. It returns the results or an error if one occurs.
+func probeNodes(nodeMetaByAddr map[netip.Addr]nodeMeta, stableConns map[stableConnKey][2]*connAndMeasureFn, portsByProtocol map[protocol][]int) ([]result, error) {
 	wg := sync.WaitGroup{}
 	results := make([]result, 0)
 	resultsCh := make(chan result)
@@ -283,40 +593,19 @@ func probeNodes(nodeMetaByAddr map[netip.Addr]nodeMeta, stableConns map[netip.Ad
 	at := time.Now()
 	addrsToProbe := make(map[netip.Addr]bool)
 
-	doProbe := func(conn io.ReadWriteCloser, meta nodeMeta, source timestampSource, dstPort int) {
+	doProbe := func(cf *connAndMeasureFn, meta nodeMeta, source timestampSource, stable connStability, protocol protocol, dstPort int) {
 		defer wg.Done()
 		r := result{
 			key: resultKey{
 				meta:            meta,
 				timestampSource: source,
+				connStability:   stable,
 				dstPort:         dstPort,
+				protocol:        protocol,
 			},
 			at: at,
 		}
-		if conn == nil {
-			var err error
-			if source == timestampSourceKernel {
-				conn, err = getConnKernelTimestamp()
-			} else {
-				conn, err = net.ListenUDP("udp", &net.UDPAddr{})
-			}
-			if err != nil {
-				select {
-				case <-doneCh:
-					return
-				case errCh <- err:
-					return
-				}
-			}
-			defer conn.Close()
-		} else {
-			r.key.connStability = stableConn
-		}
-		fn := measureRTT
-		if source == timestampSourceKernel {
-			fn = measureRTTKernel
-		}
-		rtt, err := probe(meta, conn, fn, dstPort)
+		rtt, err := probe(meta, cf, dstPort)
 		if err != nil {
 			select {
 			case <-doneCh:
@@ -334,37 +623,42 @@ func probeNodes(nodeMetaByAddr map[netip.Addr]nodeMeta, stableConns map[netip.Ad
 
 	for _, meta := range nodeMetaByAddr {
 		addrsToProbe[meta.addr] = true
-		for _, port := range dstPorts {
-			stable, err := getStableConns(stableConns, meta.addr, port)
-			if err != nil {
-				close(doneCh)
-				wg.Wait()
-				return nil, err
-			}
+		for p, ports := range portsByProtocol {
+			for _, port := range ports {
+				stable, unstable, err := getConns(stableConns, meta.addr, p, port)
+				if err != nil {
+					close(doneCh)
+					wg.Wait()
+					return nil, err
+				}
 
-			wg.Add(2)
-			numProbes += 2
-			go doProbe(stable[timestampSourceUserspace], meta, timestampSourceUserspace, port)
-			go doProbe(nil, meta, timestampSourceUserspace, port)
-			if supportsKernelTS() {
-				wg.Add(2)
-				numProbes += 2
-				go doProbe(stable[timestampSourceKernel], meta, timestampSourceKernel, port)
-				go doProbe(nil, meta, timestampSourceKernel, port)
+				for i, cf := range stable {
+					if cf != nil {
+						wg.Add(1)
+						numProbes++
+						go doProbe(cf, meta, timestampSource(i), stableConn, p, port)
+					}
+				}
+
+				for i, cf := range unstable {
+					if cf != nil {
+						wg.Add(1)
+						numProbes++
+						go doProbe(cf, meta, timestampSource(i), unstableConn, p, port)
+					}
+				}
 			}
 		}
 	}
 
 	// cleanup conns we no longer need
-	for k, byDstPort := range stableConns {
-		if !addrsToProbe[k] {
-			for _, conns := range byDstPort {
-				if conns[timestampSourceKernel] != nil {
-					conns[timestampSourceKernel].Close()
-				}
-				conns[timestampSourceUserspace].Close()
-				delete(stableConns, k)
+	for k, cf := range stableConns {
+		if !addrsToProbe[k.node] {
+			if cf[timestampSourceKernel] != nil {
+				cf[timestampSourceKernel].conn.Close()
 			}
+			cf[timestampSourceUserspace].conn.Close()
+			delete(stableConns, k)
 		}
 	}
 
@@ -391,11 +685,11 @@ const (
 )
 
 const (
-	rttMetricName      = "stunstamp_derp_stun_rtt_ns"
-	timeoutsMetricName = "stunstamp_derp_stun_timeouts_total"
+	rttMetricName      = "stunstamp_derp_rtt_ns"
+	timeoutsMetricName = "stunstamp_derp_timeouts_total"
 )
 
-func timeSeriesLabels(metricName string, meta nodeMeta, instance string, source timestampSource, stability connStability, dstPort int) []prompb.Label {
+func timeSeriesLabels(metricName string, meta nodeMeta, instance string, source timestampSource, stability connStability, protocol protocol, dstPort int) []prompb.Label {
 	addressFamily := "ipv4"
 	if meta.addr.Is6() {
 		addressFamily = "ipv6"
@@ -425,6 +719,10 @@ func timeSeriesLabels(metricName string, meta nodeMeta, instance string, source
 		Name:  "hostname",
 		Value: meta.hostname,
 	})
+	labels = append(labels, prompb.Label{
+		Name:  "protocol",
+		Value: string(protocol),
+	})
 	labels = append(labels, prompb.Label{
 		Name:  "dst_port",
 		Value: strconv.Itoa(dstPort),
@@ -453,53 +751,35 @@ const (
 	staleNaN uint64 = 0x7ff0000000000002
 )
 
-func staleMarkersFromNodeMeta(stale []nodeMeta, instance string, dstPorts []int) []prompb.TimeSeries {
+func staleMarkersFromNodeMeta(stale []nodeMeta, instance string, portsByProtocol map[protocol][]int) []prompb.TimeSeries {
 	staleMarkers := make([]prompb.TimeSeries, 0)
 	now := time.Now()
-	for _, s := range stale {
-		for _, dstPort := range dstPorts {
-			samples := []prompb.Sample{
-				{
-					Timestamp: now.UnixMilli(),
-					Value:     math.Float64frombits(staleNaN),
-				},
-			}
-			staleMarkers = append(staleMarkers, prompb.TimeSeries{
-				Labels:  timeSeriesLabels(rttMetricName, s, instance, timestampSourceUserspace, unstableConn, dstPort),
-				Samples: samples,
-			})
-			staleMarkers = append(staleMarkers, prompb.TimeSeries{
-				Labels:  timeSeriesLabels(rttMetricName, s, instance, timestampSourceUserspace, stableConn, dstPort),
-				Samples: samples,
-			})
-			staleMarkers = append(staleMarkers, prompb.TimeSeries{
-				Labels:  timeSeriesLabels(timeoutsMetricName, s, instance, timestampSourceUserspace, unstableConn, dstPort),
-				Samples: samples,
-			})
-			staleMarkers = append(staleMarkers, prompb.TimeSeries{
-				Labels:  timeSeriesLabels(timeoutsMetricName, s, instance, timestampSourceUserspace, stableConn, dstPort),
-				Samples: samples,
-			})
-			if supportsKernelTS() {
-				staleMarkers = append(staleMarkers, prompb.TimeSeries{
-					Labels:  timeSeriesLabels(rttMetricName, s, instance, timestampSourceKernel, unstableConn, dstPort),
-					Samples: samples,
-				})
-				staleMarkers = append(staleMarkers, prompb.TimeSeries{
-					Labels:  timeSeriesLabels(rttMetricName, s, instance, timestampSourceKernel, stableConn, dstPort),
-					Samples: samples,
-				})
-				staleMarkers = append(staleMarkers, prompb.TimeSeries{
-					Labels:  timeSeriesLabels(timeoutsMetricName, s, instance, timestampSourceKernel, unstableConn, dstPort),
-					Samples: samples,
-				})
-				staleMarkers = append(staleMarkers, prompb.TimeSeries{
-					Labels:  timeSeriesLabels(timeoutsMetricName, s, instance, timestampSourceKernel, stableConn, dstPort),
-					Samples: samples,
-				})
+
+	for p, ports := range portsByProtocol {
+		for _, port := range ports {
+			for _, s := range stale {
+				samples := []prompb.Sample{
+					{
+						Timestamp: now.UnixMilli(),
+						Value:     math.Float64frombits(staleNaN),
+					},
+				}
+				// We send stale markers for all combinations in the interest
+				// of simplicity.
+				for _, name := range []string{rttMetricName, timeoutsMetricName} {
+					for _, source := range []timestampSource{timestampSourceUserspace, timestampSourceKernel} {
+						for _, stable := range []connStability{unstableConn, stableConn} {
+							staleMarkers = append(staleMarkers, prompb.TimeSeries{
+								Labels:  timeSeriesLabels(name, s, instance, source, stable, p, port),
+								Samples: samples,
+							})
+						}
+					}
+				}
 			}
 		}
 	}
+
 	return staleMarkers
 }
 
@@ -513,7 +793,7 @@ func resultsToPromTimeSeries(results []result, instance string, timeouts map[res
 	for _, r := range results {
 		timeoutsCount := timeouts[r.key] // a non-existent key will return a zero val
 		seenKeys[r.key] = true
-		rttLabels := timeSeriesLabels(rttMetricName, r.key.meta, instance, r.key.timestampSource, r.key.connStability, r.key.dstPort)
+		rttLabels := timeSeriesLabels(rttMetricName, r.key.meta, instance, r.key.timestampSource, r.key.connStability, r.key.protocol, r.key.dstPort)
 		rttSamples := make([]prompb.Sample, 1)
 		rttSamples[0].Timestamp = r.at.UnixMilli()
 		if r.rtt != nil {
@@ -528,7 +808,7 @@ func resultsToPromTimeSeries(results []result, instance string, timeouts map[res
 		}
 		all = append(all, rttTS)
 		timeouts[r.key] = timeoutsCount
-		timeoutsLabels := timeSeriesLabels(timeoutsMetricName, r.key.meta, instance, r.key.timestampSource, r.key.connStability, r.key.dstPort)
+		timeoutsLabels := timeSeriesLabels(timeoutsMetricName, r.key.meta, instance, r.key.timestampSource, r.key.connStability, r.key.protocol, r.key.dstPort)
 		timeoutsSamples := make([]prompb.Sample, 1)
 		timeoutsSamples[0].Timestamp = r.at.UnixMilli()
 		timeoutsSamples[0].Value = float64(timeoutsCount)
@@ -620,38 +900,76 @@ func remoteWriteTimeSeries(client *remoteWriteClient, tsCh chan []prompb.TimeSer
 	}
 }
 
-func main() {
-	flag.Parse()
-	if len(*flagDstPorts) == 0 {
-		log.Fatal("dst-ports flag is unset")
+func getPortsFromFlag(f string) ([]int, error) {
+	if len(f) == 0 {
+		return nil, nil
 	}
-	dstPortsSplit := strings.Split(*flagDstPorts, ",")
-	slices.Sort(dstPortsSplit)
-	dstPortsSplit = slices.Compact(dstPortsSplit)
-	dstPorts := make([]int, 0, len(dstPortsSplit))
-	for _, d := range dstPortsSplit {
-		i, err := strconv.ParseUint(d, 10, 16)
+	split := strings.Split(f, ",")
+	slices.Sort(split)
+	split = slices.Compact(split)
+	ports := make([]int, 0)
+	for _, portStr := range split {
+		port, err := strconv.ParseUint(portStr, 10, 16)
 		if err != nil {
-			log.Fatal("invalid dst-ports")
+			return nil, err
 		}
-		dstPorts = append(dstPorts, int(i))
+		ports = append(ports, int(port))
 	}
+	return ports, nil
+}
+
+func main() {
+	if runtime.GOOS != "linux" && runtime.GOOS != "darwin" {
+		log.Fatal("unsupported platform")
+	}
+	flag.Parse()
+
+	portsByProtocol := make(map[protocol][]int)
+	stunPorts, err := getPortsFromFlag(*flagSTUNDstPorts)
+	if err != nil {
+		log.Fatalf("invalid stun-dst-ports flag value: %v", err)
+	}
+	if len(stunPorts) > 0 {
+		portsByProtocol[protocolSTUN] = stunPorts
+	}
+	httpsPorts, err := getPortsFromFlag(*flagHTTPSDstPorts)
+	if err != nil {
+		log.Fatalf("invalid https-dst-ports flag value: %v", err)
+	}
+	if len(httpsPorts) > 0 {
+		portsByProtocol[protocolHTTPS] = httpsPorts
+	}
+	tcpPorts, err := getPortsFromFlag(*flagTCPDstPorts)
+	if err != nil {
+		log.Fatalf("invalid tcp-dst-ports flag value: %v", err)
+	}
+	if len(tcpPorts) > 0 {
+		portsByProtocol[protocolTCP] = tcpPorts
+	}
+	if *flagICMP {
+		portsByProtocol[protocolICMP] = []int{0}
+	}
+	if len(portsByProtocol) == 0 {
+		log.Fatal("nothing to probe")
+	}
+
+	// TODO(jwhited): remove protocol restriction
+	for k := range portsByProtocol {
+		if k != protocolSTUN && k != protocolHTTPS && k != protocolTCP {
+			log.Fatal("ICMP is not yet supported")
+		}
+	}
+
 	if len(*flagDERPMap) < 1 {
 		log.Fatal("derp-map flag is unset")
 	}
-	if len(*flagOut) < 1 {
-		log.Fatal("out flag is unset")
-	}
 	if *flagInterval < minInterval || *flagInterval > maxBufferDuration {
 		log.Fatalf("interval must be >= %s and <= %s", minInterval, maxBufferDuration)
 	}
-	if *flagRetention < *flagInterval {
-		log.Fatal("retention must be >= interval")
-	}
 	if len(*flagRemoteWriteURL) < 1 {
 		log.Fatal("rw-url flag is unset")
 	}
-	_, err := url.Parse(*flagRemoteWriteURL)
+	_, err = url.Parse(*flagRemoteWriteURL)
 	if err != nil {
 		log.Fatalf("invalid rw-url flag value: %v", err)
 	}
@@ -693,49 +1011,6 @@ func main() {
 		}
 	}
 
-	db, err := newDB(*flagOut)
-	if err != nil {
-		log.Fatalf("error opening output file for writing: %v", err)
-	}
-	defer db.Close()
-
-	_, err = db.Exec("PRAGMA journal_mode=WAL")
-	if err != nil {
-		log.Fatalf("error enabling WAL mode: %v", err)
-	}
-
-	// No indices or primary key. Keep it simple for now. Reads will be full
-	// scans. We can AUTOINCREMENT rowid in the future and hold an in-memory
-	// index to at_unix if needed as reads are almost always going to be
-	// time-bound (e.g. WHERE at_unix >= ?). At the time of authorship we have
-	// ~300 data points per-interval w/o ipv6 w/kernel timestamping resulting
-	// in ~2.6m rows in 24h w/a 10s probe interval.
-	_, err = db.Exec(`
-CREATE TABLE IF NOT EXISTS rtt(at_unix INT, region_id INT, hostname TEXT, af INT, address TEXT, timestamp_source INT, stable_conn INT, dst_port INT, rtt_ns INT)
-`)
-	if err != nil {
-		log.Fatalf("error initializing db: %v", err)
-	}
-
-	wg := sync.WaitGroup{}
-	httpErrCh := make(chan error, 1)
-	var httpServer *http.Server
-	if len(*flagAPI) > 0 {
-		api := newAPI(db)
-		httpServer = &http.Server{
-			Addr:         *flagAPI,
-			Handler:      api,
-			ReadTimeout:  time.Second * 60,
-			WriteTimeout: time.Second * 60,
-		}
-		wg.Add(1)
-		go func() {
-			err := httpServer.ListenAndServe()
-			httpErrCh <- err
-			wg.Done()
-		}()
-	}
-
 	tsCh := make(chan []prompb.TimeSeries, maxBufferDuration / *flagInterval)
 	remoteWriteDoneCh := make(chan struct{})
 	rwc := newRemoteWriteClient(*flagRemoteWriteURL)
@@ -745,9 +1020,6 @@ CREATE TABLE IF NOT EXISTS rtt(at_unix INT, region_id INT, hostname TEXT, af INT
 	}()
 
 	shutdown := func() {
-		if httpServer != nil {
-			httpServer.Close()
-		}
 		close(tsCh)
 		select {
 		case <-time.After(time.Second * 10): // give goroutine some time to flush
@@ -759,14 +1031,13 @@ CREATE TABLE IF NOT EXISTS rtt(at_unix INT, region_id INT, hostname TEXT, af INT
 		for _, v := range nodeMetaByAddr {
 			staleMeta = append(staleMeta, v)
 		}
-		staleMarkers := staleMarkersFromNodeMeta(staleMeta, *flagInstance, dstPorts)
+		staleMarkers := staleMarkersFromNodeMeta(staleMeta, *flagInstance, portsByProtocol)
 		if len(staleMarkers) > 0 {
 			ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 			rwc.write(ctx, staleMarkers)
 			cancel()
 		}
 
-		wg.Wait()
 		return
 	}
 
@@ -776,8 +1047,8 @@ CREATE TABLE IF NOT EXISTS rtt(at_unix INT, region_id INT, hostname TEXT, af INT
 	// in a higher probability of the packets traversing the same underlay path.
 	// Comparison of stable and unstable 5-tuple results can shed light on
 	// differences between paths where hashing (multipathing/load balancing)
-	// comes into play.
-	stableConns := make(map[netip.Addr]map[int][2]io.ReadWriteCloser)
+	// comes into play. The inner 2 element array index is timestampSource.
+	stableConns := make(map[stableConnKey][2]*connAndMeasureFn)
 
 	// timeouts holds counts of timeout events. Values are persisted for the
 	// lifetime of the related node in the DERP map.
@@ -787,22 +1058,11 @@ CREATE TABLE IF NOT EXISTS rtt(at_unix INT, region_id INT, hostname TEXT, af INT
 	defer derpMapTicker.Stop()
 	probeTicker := time.NewTicker(*flagInterval)
 	defer probeTicker.Stop()
-	cleanupTicker := time.NewTicker(time.Hour)
-	defer cleanupTicker.Stop()
 
 	for {
 		select {
-		case <-cleanupTicker.C:
-			older := time.Now().Add(-*flagRetention)
-			log.Printf("cleaning up measurements older than %v", older)
-			_, err := db.Exec("DELETE FROM rtt WHERE at_unix < ?", older.Unix())
-			if err != nil {
-				log.Printf("error cleaning up old data: %v", err)
-				shutdown()
-				return
-			}
 		case <-probeTicker.C:
-			results, err := probeNodes(nodeMetaByAddr, stableConns, dstPorts)
+			results, err := probeNodes(nodeMetaByAddr, stableConns, portsByProtocol)
 			if err != nil {
 				log.Printf("unrecoverable error while probing: %v", err)
 				shutdown()
@@ -819,39 +1079,13 @@ CREATE TABLE IF NOT EXISTS rtt(at_unix INT, region_id INT, hostname TEXT, af INT
 					tsCh <- ts
 				}
 			}
-			tx, err := db.Begin()
-			if err != nil {
-				log.Printf("error beginning sqlite tx: %v", err)
-				shutdown()
-				return
-			}
-			for _, result := range results {
-				af := 4
-				if result.key.meta.addr.Is6() {
-					af = 6
-				}
-				_, err = tx.Exec("INSERT INTO rtt(at_unix, region_id, hostname, af, address, timestamp_source, stable_conn, dst_port, rtt_ns) VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?)",
-					result.at.Unix(), result.key.meta.regionID, result.key.meta.hostname, af, result.key.meta.addr.String(), result.key.timestampSource, result.key.connStability, result.key.dstPort, result.rtt)
-				if err != nil {
-					tx.Rollback()
-					log.Printf("error adding result to tx: %v", err)
-					shutdown()
-					return
-				}
-			}
-			err = tx.Commit()
-			if err != nil {
-				log.Printf("error committing tx: %v", err)
-				shutdown()
-				return
-			}
 		case dm := <-dmCh:
 			staleMeta, err := nodeMetaFromDERPMap(dm, nodeMetaByAddr, *flagIPv6)
 			if err != nil {
 				log.Printf("error parsing DERP map, continuing with stale map: %v", err)
 				continue
 			}
-			staleMarkers := staleMarkersFromNodeMeta(staleMeta, *flagInstance, dstPorts)
+			staleMarkers := staleMarkersFromNodeMeta(staleMeta, *flagInstance, portsByProtocol)
 			if len(staleMarkers) < 1 {
 				continue
 			}
@@ -870,14 +1104,10 @@ CREATE TABLE IF NOT EXISTS rtt(at_unix INT, region_id INT, hostname TEXT, af INT
 				ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
 				defer cancel()
 				updatedDM, err := getDERPMap(ctx, *flagDERPMap)
-				if err != nil {
+				if err == nil {
 					dmCh <- updatedDM
 				}
 			}()
-		case err := <-httpErrCh:
-			log.Printf("http server error: %v", err)
-			shutdown()
-			return
 		case <-sigCh:
 			shutdown()
 			return

cmd/stunstamp/stunstamp_db_default.go

@@ -1,26 +0,0 @@
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-
-//go:build !(windows && 386)
-
-package main
-
-import (
-	"database/sql"
-
-	_ "modernc.org/sqlite"
-)
-
-type db struct {
-	*sql.DB
-}
-
-func newDB(path string) (*db, error) {
-	d, err := sql.Open("sqlite", *flagOut)
-	if err != nil {
-		return nil, err
-	}
-	return &db{
-		DB: d,
-	}, nil
-}

cmd/stunstamp/stunstamp_db_windows_386.go

@@ -1,17 +0,0 @@
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-
-package main
-
-import (
-	"database/sql"
-	"errors"
-)
-
-type db struct {
-	*sql.DB
-}
-
-func newDB(path string) (*db, error) {
-	return nil, errors.New("unsupported platform")
-}

cmd/stunstamp/stunstamp_default.go

@@ -8,18 +8,42 @@ package main
 import (
 	"errors"
 	"io"
-	"net"
+	"net/netip"
 	"time"
 )
 
-func getConnKernelTimestamp() (io.ReadWriteCloser, error) {
+func getUDPConnKernelTimestamp() (io.ReadWriteCloser, error) {
 	return nil, errors.New("unimplemented")
 }
 
-func measureRTTKernel(conn io.ReadWriteCloser, dst *net.UDPAddr) (rtt time.Duration, err error) {
+func measureSTUNRTTKernel(conn io.ReadWriteCloser, hostname string, dst netip.AddrPort) (rtt time.Duration, err error) {
 	return 0, errors.New("unimplemented")
 }
 
-func supportsKernelTS() bool {
-	return false
+func getProtocolSupportInfo(p protocol) protocolSupportInfo {
+	switch p {
+	case protocolSTUN:
+		return protocolSupportInfo{
+			kernelTS:    false,
+			userspaceTS: true,
+			stableConn:  true,
+		}
+	case protocolHTTPS:
+		return protocolSupportInfo{
+			kernelTS:    false,
+			userspaceTS: true,
+			stableConn:  true,
+		}
+	case protocolTCP:
+		return protocolSupportInfo{
+			kernelTS:    true,
+			userspaceTS: false,
+			stableConn:  true,
+		}
+	}
+	return protocolSupportInfo{}
+}
+
+func setSOReuseAddr(fd uintptr) error {
+	return nil
 }

cmd/stunstamp/stunstamp_linux.go

@@ -10,7 +10,8 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"net"
+	"net/netip"
+	"syscall"
 	"time"
 
 	"github.com/mdlayher/socket"
@@ -24,7 +25,7 @@ const (
 		unix.SOF_TIMESTAMPING_SOFTWARE // report software timestamps
 )
 
-func getConnKernelTimestamp() (io.ReadWriteCloser, error) {
+func getUDPConnKernelTimestamp() (io.ReadWriteCloser, error) {
 	sconn, err := socket.Socket(unix.AF_INET6, unix.SOCK_DGRAM, unix.IPPROTO_UDP, "udp", nil)
 	if err != nil {
 		return nil, err
@@ -56,24 +57,23 @@ func parseTimestampFromCmsgs(oob []byte) (time.Time, error) {
 	return time.Time{}, errors.New("failed to parse timestamp from cmsgs")
 }
 
-func measureRTTKernel(conn io.ReadWriteCloser, dst *net.UDPAddr) (rtt time.Duration, err error) {
+func measureSTUNRTTKernel(conn io.ReadWriteCloser, hostname string, dst netip.AddrPort) (rtt time.Duration, err error) {
 	sconn, ok := conn.(*socket.Conn)
 	if !ok {
 		return 0, fmt.Errorf("conn of unexpected type: %T", conn)
 	}
 
 	var to unix.Sockaddr
-	to4 := dst.IP.To4()
-	if to4 != nil {
+	if dst.Addr().Is4() {
 		to = &unix.SockaddrInet4{
-			Port: dst.Port,
+			Port: int(dst.Port()),
 		}
-		copy(to.(*unix.SockaddrInet4).Addr[:], to4)
+		copy(to.(*unix.SockaddrInet4).Addr[:], dst.Addr().AsSlice())
 	} else {
 		to = &unix.SockaddrInet6{
-			Port: dst.Port,
+			Port: int(dst.Port()),
 		}
-		copy(to.(*unix.SockaddrInet6).Addr[:], dst.IP)
+		copy(to.(*unix.SockaddrInet6).Addr[:], dst.Addr().AsSlice())
 	}
 
 	txID := stun.NewTxID()
@@ -138,6 +138,32 @@ func measureRTTKernel(conn io.ReadWriteCloser, dst *net.UDPAddr) (rtt time.Durat
 
 }
 
-func supportsKernelTS() bool {
-	return true
+func getProtocolSupportInfo(p protocol) protocolSupportInfo {
+	switch p {
+	case protocolSTUN:
+		return protocolSupportInfo{
+			kernelTS:    true,
+			userspaceTS: true,
+			stableConn:  true,
+		}
+	case protocolHTTPS:
+		return protocolSupportInfo{
+			kernelTS:    false,
+			userspaceTS: true,
+			stableConn:  true,
+		}
+	case protocolTCP:
+		return protocolSupportInfo{
+			kernelTS:    true,
+			userspaceTS: false,
+			stableConn:  true,
+		}
+		// TODO(jwhited): add ICMP
+	}
+	return protocolSupportInfo{}
+}
+
+func setSOReuseAddr(fd uintptr) error {
+	// we may restart faster than TIME_WAIT can clear
+	return syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
 }

cmd/tailscale/cli/cert.go

@@ -16,6 +16,7 @@ import (
 	"net/http"
 	"os"
 	"strings"
+	"time"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
 	"software.sslmate.com/src/go-pkcs12"
@@ -34,14 +35,16 @@ var certCmd = &ffcli.Command{
 		fs.StringVar(&certArgs.certFile, "cert-file", "", "output cert file or \"-\" for stdout; defaults to DOMAIN.crt if --cert-file and --key-file are both unset")
 		fs.StringVar(&certArgs.keyFile, "key-file", "", "output key file or \"-\" for stdout; defaults to DOMAIN.key if --cert-file and --key-file are both unset")
 		fs.BoolVar(&certArgs.serve, "serve-demo", false, "if true, serve on port :443 using the cert as a demo, instead of writing out the files to disk")
+		fs.DurationVar(&certArgs.minValidity, "min-validity", 0, "ensure the certificate is valid for at least this duration; the output certificate is never expired if this flag is unset or 0, but the lifetime may vary; the maximum allowed min-validity depends on the CA")
 		return fs
 	})(),
 }
 
 var certArgs struct {
-	certFile string
-	keyFile  string
-	serve    bool
+	certFile    string
+	keyFile     string
+	serve       bool
+	minValidity time.Duration
 }
 
 func runCert(ctx context.Context, args []string) error {
@@ -102,7 +105,7 @@ func runCert(ctx context.Context, args []string) error {
 		certArgs.certFile = domain + ".crt"
 		certArgs.keyFile = domain + ".key"
 	}
-	certPEM, keyPEM, err := localClient.CertPair(ctx, domain)
+	certPEM, keyPEM, err := localClient.CertPairWithValidity(ctx, domain, certArgs.minValidity)
 	if err != nil {
 		return err
 	}

cmd/tailscale/cli/cli.go

@@ -84,6 +84,13 @@ var localClient = tailscale.LocalClient{
 
 // Run runs the CLI. The args do not include the binary name.
 func Run(args []string) (err error) {
+	if runtime.GOOS == "linux" && os.Getenv("GOKRAZY_FIRST_START") == "1" && distro.Get() == distro.Gokrazy && os.Getppid() == 1 {
+		// We're running on gokrazy and it's the first start.
+		// Don't run the tailscale CLI as a service; just exit.
+		// See https://gokrazy.org/development/process-interface/
+		os.Exit(0)
+	}
+
 	args = CleanUpArgs(args)
 
 	if len(args) == 1 && (args[0] == "-V" || args[0] == "--version") {

cmd/tailscale/cli/drive.go

@@ -6,6 +6,7 @@ package cli
 import (
 	"context"
 	"fmt"
+	"path/filepath"
 	"strings"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
@@ -66,9 +67,14 @@ func runDriveShare(ctx context.Context, args []string) error {
 
 	name, path := args[0], args[1]
 
-	err := localClient.DriveShareSet(ctx, &drive.Share{
+	absolutePath, err := filepath.Abs(path)
+	if err != nil {
+		return err
+	}
+
+	err = localClient.DriveShareSet(ctx, &drive.Share{
 		Name: name,
-		Path: path,
+		Path: absolutePath,
 	})
 	if err == nil {
 		fmt.Printf("Sharing %q as %q\n", path, name)

cmd/tailscale/cli/exitnode.go

@@ -13,6 +13,7 @@ import (
 	"strings"
 	"text/tabwriter"
 
+	"github.com/kballard/go-shellquote"
 	"github.com/peterbourgon/ff/v3/ffcli"
 	xmaps "golang.org/x/exp/maps"
 	"tailscale.com/envknob"
@@ -136,6 +137,7 @@ func runExitNodeList(ctx context.Context, args []string) error {
 	}
 	fmt.Fprintln(w)
 	fmt.Fprintln(w)
+	fmt.Fprintln(w, "# To view the complete list of exit nodes for a country, use `tailscale exit-node list --filter=` followed by the country name.")
 	fmt.Fprintln(w, "# To use an exit node, use `tailscale set --exit-node=` followed by the hostname or IP.")
 	if hasAnyExitNodeSuggestions(peers) {
 		fmt.Fprintln(w, "# To have Tailscale suggest an exit node, use `tailscale exit-node suggest`.")
@@ -154,7 +156,7 @@ func runExitNodeSuggest(ctx context.Context, args []string) error {
 		fmt.Println("No exit node suggestion is available.")
 		return nil
 	}
-	fmt.Printf("Suggested exit node: %v\nTo accept this suggestion, use `tailscale set --exit-node=%v`.\n", res.Name, res.ID)
+	fmt.Printf("Suggested exit node: %v\nTo accept this suggestion, use `tailscale set --exit-node=%v`.\n", res.Name, shellquote.Join(res.Name))
 	return nil
 }
 
@@ -229,7 +231,7 @@ func filterFormatAndSortExitNodes(peers []*ipnstate.PeerStatus, filterBy string)
 	for _, ps := range peers {
 		loc := cmp.Or(ps.Location, noLocation)
 
-		if filterBy != "" && loc.Country != filterBy {
+		if filterBy != "" && !strings.EqualFold(loc.Country, filterBy) {
 			continue
 		}
 
@@ -269,9 +271,14 @@ func filterFormatAndSortExitNodes(peers []*ipnstate.PeerStatus, filterBy string)
 			countryAnyPeer = append(countryAnyPeer, city.Peers...)
 			var reducedCityPeers []*ipnstate.PeerStatus
 			for i, peer := range city.Peers {
+				if filterBy != "" {
+					// If the peers are being filtered, we return all peers to the user.
+					reducedCityPeers = append(reducedCityPeers, city.Peers...)
+					break
+				}
+				// If the peers are not being filtered, we only return the highest priority peer and any peer that
+				// is currently the active exit node.
 				if i == 0 || peer.ExitNode {
-					// We only return the highest priority peer and any peer that
-					// is currently the active exit node.
 					reducedCityPeers = append(reducedCityPeers, peer)
 				}
 			}

cmd/tailscale/cli/exitnode_test.go

@@ -219,7 +219,7 @@ func TestFilterFormatAndSortExitNodes(t *testing.T) {
 						{
 							Name: "Rainier",
 							Peers: []*ipnstate.PeerStatus{
-								ps[2],
+								ps[2], ps[3],
 							},
 						},
 					},

cmd/tailscale/cli/ffcomplete/internal/complete.go

@@ -1,6 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// Package internal contains internal code for the ffcomplete package.
 package internal
 
 import (

cmd/tailscale/cli/netcheck.go

@@ -52,9 +52,15 @@ func runNetcheck(ctx context.Context, args []string) error {
 	if err != nil {
 		return err
 	}
+
+	// Ensure that we close the portmapper after running a netcheck; this
+	// will release any port mappings created.
+	pm := portmapper.NewClient(logf, netMon, nil, nil, nil)
+	defer pm.Close()
+
 	c := &netcheck.Client{
 		NetMon:      netMon,
-		PortMapper:  portmapper.NewClient(logf, netMon, nil, nil, nil),
+		PortMapper:  pm,
 		UseDNSCache: false, // always resolve, don't cache
 	}
 	if netcheckArgs.verbose {

cmd/tailscale/cli/network-lock.go

@@ -20,6 +20,7 @@ import (
 	"github.com/peterbourgon/ff/v3/ffcli"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tka"
+	"tailscale.com/tsconst"
 	"tailscale.com/types/key"
 	"tailscale.com/types/tkatype"
 )
@@ -443,15 +444,33 @@ func runNetworkLockModify(ctx context.Context, addArgs, removeArgs []string) err
 
 var nlSignCmd = &ffcli.Command{
 	Name:       "sign",
-	ShortUsage: "tailscale lock sign <node-key> [<rotation-key>] or sign <auth-key>",
+	ShortUsage: "tailscale lock sign <node-key> [<rotation-key>]\ntailscale lock sign <auth-key>",
 	ShortHelp:  "Signs a node or pre-approved auth key",
 	LongHelp: `Either:
-  - signs a node key and transmits the signature to the coordination server, or
-  - signs a pre-approved auth key, printing it in a form that can be used to bring up nodes under tailnet lock`,
+  - signs a node key and transmits the signature to the coordination
+    server, or
+  - signs a pre-approved auth key, printing it in a form that can be
+    used to bring up nodes under tailnet lock
+
+If any of the key arguments begin with "file:", the key is retrieved from
+the file at the path specified in the argument suffix.`,
 	Exec: runNetworkLockSign,
 }
 
 func runNetworkLockSign(ctx context.Context, args []string) error {
+	// If any of the arguments start with "file:", replace that argument
+	// with the contents of the file. We do this early, before the check
+	// to see if the first argument is an auth key.
+	for i, arg := range args {
+		if filename, ok := strings.CutPrefix(arg, "file:"); ok {
+			b, err := os.ReadFile(filename)
+			if err != nil {
+				return err
+			}
+			args[i] = strings.TrimSpace(string(b))
+		}
+	}
+
 	if len(args) > 0 && strings.HasPrefix(args[0], "tskey-auth-") {
 		return runTskeyWrapCmd(ctx, args)
 	}
@@ -476,7 +495,7 @@ func runNetworkLockSign(ctx context.Context, args []string) error {
 	err := localClient.NetworkLockSign(ctx, nodeKey, []byte(rotationKey.Verifier()))
 	// Provide a better help message for when someone clicks through the signing flow
 	// on the wrong device.
-	if err != nil && strings.Contains(err.Error(), "this node is not trusted by network lock") {
+	if err != nil && strings.Contains(err.Error(), tsconst.TailnetLockNotTrustedMsg) {
 		fmt.Fprintln(Stderr, "Error: Signing is not available on this device because it does not have a trusted tailnet lock key.")
 		fmt.Fprintln(Stderr)
 		fmt.Fprintln(Stderr, "Try again on a signing device instead. Tailnet admins can see signing devices on the admin panel.")
@@ -789,7 +808,7 @@ func runNetworkLockRevokeKeys(ctx context.Context, args []string) error {
 		}
 
 		fmt.Printf(`Run the following command on another machine with a trusted tailnet lock key:
-	%s lock recover-compromised-key --cosign %X
+	%s lock revoke-keys --cosign %X
 `, os.Args[0], aumBytes)
 		return nil
 	}
@@ -813,10 +832,10 @@ func runNetworkLockRevokeKeys(ctx context.Context, args []string) error {
 		fmt.Printf(`Co-signing completed successfully.
 
 To accumulate an additional signature, run the following command on another machine with a trusted tailnet lock key:
-	%s lock recover-compromised-key --cosign %X
+	%s lock revoke-keys --cosign %X
 
 Alternatively if you are done with co-signing, complete recovery by running the following command:
-	%s lock recover-compromised-key --finish %X
+	%s lock revoke-keys --finish %X
 `, os.Args[0], aumBytes, os.Args[0], aumBytes)
 	}
 

cmd/tailscale/cli/serve_v2_test.go

@@ -74,7 +74,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 					TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 					Web: map[ipn.HostPort]*ipn.WebServerConfig{
 						"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-							"/": {Proxy: "http://127.0.0.1:3000"},
+							"/": {Proxy: "http://localhost:3000"},
 						}},
 					},
 					AllowFunnel: map[ipn.HostPort]bool{"foo.test.ts.net:443": true},
@@ -89,7 +89,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 					TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 					Web: map[ipn.HostPort]*ipn.WebServerConfig{
 						"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-							"/": {Proxy: "http://127.0.0.1:3000"},
+							"/": {Proxy: "http://localhost:3000"},
 						}},
 					},
 				},
@@ -103,7 +103,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 					TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 					Web: map[ipn.HostPort]*ipn.WebServerConfig{
 						"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-							"/": {Proxy: "http://127.0.0.1:3000"},
+							"/": {Proxy: "http://localhost:3000"},
 						}},
 					},
 				},
@@ -117,7 +117,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 					TCP: map[uint16]*ipn.TCPPortHandler{80: {HTTP: true}},
 					Web: map[ipn.HostPort]*ipn.WebServerConfig{
 						"foo.test.ts.net:80": {Handlers: map[string]*ipn.HTTPHandler{
-							"/": {Proxy: "http://127.0.0.1:3000"},
+							"/": {Proxy: "http://localhost:3000"},
 						}},
 					},
 				},
@@ -131,7 +131,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 					TCP: map[uint16]*ipn.TCPPortHandler{8443: {HTTPS: true}},
 					Web: map[ipn.HostPort]*ipn.WebServerConfig{
 						"foo.test.ts.net:8443": {Handlers: map[string]*ipn.HTTPHandler{
-							"/": {Proxy: "http://127.0.0.1:3000"},
+							"/": {Proxy: "http://localhost:3000"},
 						}},
 					},
 				},
@@ -146,7 +146,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{80: {HTTP: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:80": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -157,10 +157,10 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{80: {HTTP: true}, 9999: {HTTP: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:80": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 							"foo.test.ts.net:9999": {Handlers: map[string]*ipn.HTTPHandler{
-								"/abc": {Proxy: "http://127.0.0.1:3001"},
+								"/abc": {Proxy: "http://localhost:3001"},
 							}},
 						},
 					},
@@ -171,7 +171,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{80: {HTTP: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:80": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -182,7 +182,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{80: {HTTP: true}, 8080: {HTTP: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:80": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 							"foo.test.ts.net:8080": {Handlers: map[string]*ipn.HTTPHandler{
 								"/abc": {Proxy: "http://127.0.0.1:3001"},
@@ -236,7 +236,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -247,10 +247,10 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}, 9999: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 							"foo.test.ts.net:9999": {Handlers: map[string]*ipn.HTTPHandler{
-								"/abc": {Proxy: "http://127.0.0.1:3001"},
+								"/abc": {Proxy: "http://localhost:3001"},
 							}},
 						},
 					},
@@ -261,7 +261,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -272,7 +272,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}, 8443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 							"foo.test.ts.net:8443": {Handlers: map[string]*ipn.HTTPHandler{
 								"/abc": {Proxy: "http://127.0.0.1:3001"},
@@ -361,7 +361,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/foo": {Proxy: "http://127.0.0.1:3000"},
+								"/foo": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -372,10 +372,10 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}, 8443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/foo": {Proxy: "http://127.0.0.1:3000"},
+								"/foo": {Proxy: "http://localhost:3000"},
 							}},
 							"foo.test.ts.net:8443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/foo": {Proxy: "http://127.0.0.1:3000"},
+								"/foo": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -439,7 +439,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 					want: &ipn.ServeConfig{
 						TCP: map[uint16]*ipn.TCPPortHandler{
 							443: {
-								TCPForward:   "127.0.0.1:5432",
+								TCPForward:   "localhost:5432",
 								TerminateTLS: "foo.test.ts.net",
 							},
 						},
@@ -466,7 +466,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 					want: &ipn.ServeConfig{
 						TCP: map[uint16]*ipn.TCPPortHandler{
 							443: {
-								TCPForward:   "127.0.0.1:123",
+								TCPForward:   "localhost:123",
 								TerminateTLS: "foo.test.ts.net",
 							},
 						},
@@ -560,7 +560,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -572,7 +572,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP:         map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -584,10 +584,10 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP:         map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}, 8443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 							"foo.test.ts.net:8443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/bar": {Proxy: "http://127.0.0.1:3001"},
+								"/bar": {Proxy: "http://localhost:3001"},
 							}},
 						},
 					},
@@ -599,10 +599,10 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP:         map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}, 8443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 							"foo.test.ts.net:8443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/bar": {Proxy: "http://127.0.0.1:3001"},
+								"/bar": {Proxy: "http://localhost:3001"},
 							}},
 						},
 					},
@@ -614,10 +614,10 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP:         map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}, 8443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 							"foo.test.ts.net:8443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/bar": {Proxy: "http://127.0.0.1:3001"},
+								"/bar": {Proxy: "http://localhost:3001"},
 							}},
 						},
 					},
@@ -628,7 +628,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -636,10 +636,10 @@ func TestServeDevConfigMutations(t *testing.T) {
 				{ // start a tcp forwarder on 8443
 					command: cmd("serve --bg --tcp=8443 tcp://localhost:5432"),
 					want: &ipn.ServeConfig{
-						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}, 8443: {TCPForward: "127.0.0.1:5432"}},
+						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}, 8443: {TCPForward: "localhost:5432"}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -647,7 +647,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 				{ // remove primary port http handler
 					command: cmd("serve off"),
 					want: &ipn.ServeConfig{
-						TCP: map[uint16]*ipn.TCPPortHandler{8443: {TCPForward: "127.0.0.1:5432"}},
+						TCP: map[uint16]*ipn.TCPPortHandler{8443: {TCPForward: "localhost:5432"}},
 					},
 				},
 				{ // remove tcp forwarder
@@ -717,7 +717,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 					want: &ipn.ServeConfig{
 						TCP: map[uint16]*ipn.TCPPortHandler{
 							443: {
-								TCPForward:   "127.0.0.1:5432",
+								TCPForward:   "localhost:5432",
 								TerminateTLS: "foo.test.ts.net",
 							},
 						},
@@ -738,7 +738,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{443: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -758,7 +758,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{4545: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:4545": {Handlers: map[string]*ipn.HTTPHandler{
-								"/foo": {Proxy: "http://127.0.0.1:3000"},
+								"/foo": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -769,8 +769,8 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{4545: {HTTPS: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:4545": {Handlers: map[string]*ipn.HTTPHandler{
-								"/foo": {Proxy: "http://127.0.0.1:3000"},
-								"/bar": {Proxy: "http://127.0.0.1:3000"},
+								"/foo": {Proxy: "http://localhost:3000"},
+								"/bar": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},
@@ -800,7 +800,7 @@ func TestServeDevConfigMutations(t *testing.T) {
 						TCP: map[uint16]*ipn.TCPPortHandler{3000: {HTTP: true}},
 						Web: map[ipn.HostPort]*ipn.WebServerConfig{
 							"foo.test.ts.net:3000": {Handlers: map[string]*ipn.HTTPHandler{
-								"/": {Proxy: "http://127.0.0.1:3000"},
+								"/": {Proxy: "http://localhost:3000"},
 							}},
 						},
 					},

cmd/tailscale/cli/set.go

@@ -210,6 +210,9 @@ func runSet(ctx context.Context, args []string) (retErr error) {
 		}
 	}
 	if maskedPrefs.AutoUpdateSet.ApplySet {
+		if !clientupdate.CanAutoUpdate() {
+			return errors.New("automatic updates are not supported on this platform")
+		}
 		// On macsys, tailscaled will set the Sparkle auto-update setting. It
 		// does not use clientupdate.
 		if version.IsMacSysExt() {
@@ -221,10 +224,6 @@ func runSet(ctx context.Context, args []string) (retErr error) {
 			if err != nil {
 				return fmt.Errorf("failed to enable automatic updates: %v, %q", err, out)
 			}
-		} else {
-			if !clientupdate.CanAutoUpdate() {
-				return errors.New("automatic updates are not supported on this platform")
-			}
 		}
 	}
 	checkPrefs := curPrefs.Clone()

cmd/tailscale/depaware.txt

@@ -5,10 +5,20 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
    W 💣 github.com/alexbrainman/sspi                                 from github.com/alexbrainman/sspi/internal/common+
    W    github.com/alexbrainman/sspi/internal/common                 from github.com/alexbrainman/sspi/negotiate
    W 💣 github.com/alexbrainman/sspi/negotiate                       from tailscale.com/net/tshttpproxy
+        github.com/coder/websocket                                   from tailscale.com/control/controlhttp+
+        github.com/coder/websocket/internal/errd                     from github.com/coder/websocket
+        github.com/coder/websocket/internal/util                     from github.com/coder/websocket
+        github.com/coder/websocket/internal/xsync                    from github.com/coder/websocket
    L    github.com/coreos/go-iptables/iptables                       from tailscale.com/util/linuxfw
    W 💣 github.com/dblohm7/wingoes                                   from github.com/dblohm7/wingoes/pe+
    W 💣 github.com/dblohm7/wingoes/pe                                from tailscale.com/util/winutil/authenticode
         github.com/fxamacker/cbor/v2                                 from tailscale.com/tka
+        github.com/go-json-experiment/json                           from tailscale.com/types/opt+
+        github.com/go-json-experiment/json/internal                  from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonflags        from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonopts         from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/internal/jsonwire         from github.com/go-json-experiment/json+
+        github.com/go-json-experiment/json/jsontext                  from github.com/go-json-experiment/json+
         github.com/golang/groupcache/lru                             from tailscale.com/net/dnscache
    L    github.com/google/nftables                                   from tailscale.com/util/linuxfw
    L 💣 github.com/google/nftables/alignedbuff                       from github.com/google/nftables/xt
@@ -60,10 +70,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         go4.org/netipx                                               from tailscale.com/net/tsaddr
    W 💣 golang.zx2c4.com/wireguard/windows/tunnel/winipcfg           from tailscale.com/net/netmon+
         k8s.io/client-go/util/homedir                                from tailscale.com/cmd/tailscale/cli
-        nhooyr.io/websocket                                          from tailscale.com/control/controlhttp+
-        nhooyr.io/websocket/internal/errd                            from nhooyr.io/websocket
-        nhooyr.io/websocket/internal/util                            from nhooyr.io/websocket
-        nhooyr.io/websocket/internal/xsync                           from nhooyr.io/websocket
         sigs.k8s.io/yaml                                             from tailscale.com/cmd/tailscale/cli
         sigs.k8s.io/yaml/goyaml.v2                                   from sigs.k8s.io/yaml
         software.sslmate.com/src/go-pkcs12                           from tailscale.com/cmd/tailscale/cli
@@ -94,16 +100,17 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/ipn/ipnstate                                   from tailscale.com/client/tailscale+
         tailscale.com/licenses                                       from tailscale.com/client/web+
         tailscale.com/metrics                                        from tailscale.com/derp
+        tailscale.com/net/captivedetection                           from tailscale.com/net/netcheck
         tailscale.com/net/dns/recursive                              from tailscale.com/net/dnsfallback
         tailscale.com/net/dnscache                                   from tailscale.com/control/controlhttp+
-        tailscale.com/net/dnsfallback                                from tailscale.com/control/controlhttp
+        tailscale.com/net/dnsfallback                                from tailscale.com/control/controlhttp+
         tailscale.com/net/flowtrack                                  from tailscale.com/net/packet
         tailscale.com/net/netaddr                                    from tailscale.com/ipn+
         tailscale.com/net/netcheck                                   from tailscale.com/cmd/tailscale/cli
         tailscale.com/net/neterror                                   from tailscale.com/net/netcheck+
         tailscale.com/net/netknob                                    from tailscale.com/net/netns
      💣 tailscale.com/net/netmon                                     from tailscale.com/cmd/tailscale/cli+
-        tailscale.com/net/netns                                      from tailscale.com/derp/derphttp+
+     💣 tailscale.com/net/netns                                      from tailscale.com/derp/derphttp+
         tailscale.com/net/netutil                                    from tailscale.com/client/tailscale+
         tailscale.com/net/packet                                     from tailscale.com/wgengine/capture
         tailscale.com/net/ping                                       from tailscale.com/net/netcheck
@@ -121,7 +128,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/tailcfg                                        from tailscale.com/client/tailscale+
         tailscale.com/tempfork/spf13/cobra                           from tailscale.com/cmd/tailscale/cli/ffcomplete+
         tailscale.com/tka                                            from tailscale.com/client/tailscale+
-   W    tailscale.com/tsconst                                        from tailscale.com/net/netmon
+        tailscale.com/tsconst                                        from tailscale.com/net/netmon+
         tailscale.com/tstime                                         from tailscale.com/control/controlhttp+
         tailscale.com/tstime/mono                                    from tailscale.com/tstime/rate
         tailscale.com/tstime/rate                                    from tailscale.com/cmd/tailscale/cli+
@@ -145,9 +152,11 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/util/cloudenv                                  from tailscale.com/net/dnscache+
         tailscale.com/util/cmpver                                    from tailscale.com/net/tshttpproxy+
         tailscale.com/util/ctxkey                                    from tailscale.com/types/logger
+     💣 tailscale.com/util/deephash                                  from tailscale.com/util/syspolicy/setting
    L 💣 tailscale.com/util/dirwalk                                   from tailscale.com/metrics
         tailscale.com/util/dnsname                                   from tailscale.com/cmd/tailscale/cli+
         tailscale.com/util/groupmember                               from tailscale.com/client/web
+     💣 tailscale.com/util/hashx                                     from tailscale.com/util/deephash
         tailscale.com/util/httpm                                     from tailscale.com/client/tailscale+
         tailscale.com/util/lineread                                  from tailscale.com/hostinfo+
    L    tailscale.com/util/linuxfw                                   from tailscale.com/net/netns
@@ -160,6 +169,8 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/util/singleflight                              from tailscale.com/net/dnscache+
         tailscale.com/util/slicesx                                   from tailscale.com/net/dns/recursive+
         tailscale.com/util/syspolicy                                 from tailscale.com/ipn
+        tailscale.com/util/syspolicy/internal                        from tailscale.com/util/syspolicy/setting
+        tailscale.com/util/syspolicy/setting                         from tailscale.com/util/syspolicy
         tailscale.com/util/testenv                                   from tailscale.com/cmd/tailscale/cli
         tailscale.com/util/truncate                                  from tailscale.com/cmd/tailscale/cli
         tailscale.com/util/vizerror                                  from tailscale.com/tailcfg+
@@ -184,7 +195,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         golang.org/x/crypto/pbkdf2                                   from software.sslmate.com/src/go-pkcs12
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
    W    golang.org/x/exp/constraints                                 from github.com/dblohm7/wingoes/pe+
-        golang.org/x/exp/maps                                        from tailscale.com/cmd/tailscale/cli
+        golang.org/x/exp/maps                                        from tailscale.com/cmd/tailscale/cli+
         golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
         golang.org/x/net/dns/dnsmessage                              from net+
         golang.org/x/net/http/httpguts                               from net/http+
@@ -301,7 +312,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         reflect                                                      from archive/tar+
         regexp                                                       from github.com/coreos/go-iptables/iptables+
         regexp/syntax                                                from regexp
-        runtime/debug                                                from nhooyr.io/websocket/internal/xsync+
+        runtime/debug                                                from github.com/coder/websocket/internal/xsync+
         slices                                                       from tailscale.com/client/web+
         sort                                                         from archive/tar+
         strconv                                                      from archive/tar+

cmd/tailscaled/depaware.txt

@@ -79,6 +79,10 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    L    github.com/aws/smithy-go/transport/http/internal/io          from github.com/aws/smithy-go/transport/http
    L    github.com/aws/smithy-go/waiter                              from github.com/aws/aws-sdk-go-v2/service/ssm
         github.com/bits-and-blooms/bitset                            from github.com/gaissmai/bart
+        github.com/coder/websocket                                   from tailscale.com/control/controlhttp+
+        github.com/coder/websocket/internal/errd                     from github.com/coder/websocket
+        github.com/coder/websocket/internal/util                     from github.com/coder/websocket
+        github.com/coder/websocket/internal/xsync                    from github.com/coder/websocket
    L    github.com/coreos/go-iptables/iptables                       from tailscale.com/util/linuxfw
   LD 💣 github.com/creack/pty                                        from tailscale.com/ssh/tailssh
    W 💣 github.com/dblohm7/wingoes                                   from github.com/dblohm7/wingoes/com+
@@ -90,11 +94,12 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
      💣 github.com/djherbis/times                                    from tailscale.com/drive/driveimpl
         github.com/fxamacker/cbor/v2                                 from tailscale.com/tka
         github.com/gaissmai/bart                                     from tailscale.com/net/tstun+
+        github.com/go-json-experiment/json                           from tailscale.com/types/opt+
         github.com/go-json-experiment/json/internal                  from github.com/go-json-experiment/json/internal/jsonflags+
         github.com/go-json-experiment/json/internal/jsonflags        from github.com/go-json-experiment/json/internal/jsonopts+
-        github.com/go-json-experiment/json/internal/jsonopts         from github.com/go-json-experiment/json/jsontext
-        github.com/go-json-experiment/json/internal/jsonwire         from github.com/go-json-experiment/json/jsontext
-        github.com/go-json-experiment/json/jsontext                  from tailscale.com/logtail
+        github.com/go-json-experiment/json/internal/jsonopts         from github.com/go-json-experiment/json/jsontext+
+        github.com/go-json-experiment/json/internal/jsonwire         from github.com/go-json-experiment/json/jsontext+
+        github.com/go-json-experiment/json/jsontext                  from tailscale.com/logtail+
    W 💣 github.com/go-ole/go-ole                                     from github.com/go-ole/go-ole/oleutil+
    W 💣 github.com/go-ole/go-ole/oleutil                             from tailscale.com/wgengine/winnet
    L 💣 github.com/godbus/dbus/v5                                    from tailscale.com/net/dns+
@@ -211,7 +216,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         gvisor.dev/gvisor/pkg/tcpip/header                           from gvisor.dev/gvisor/pkg/tcpip/header/parse+
         gvisor.dev/gvisor/pkg/tcpip/header/parse                     from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
         gvisor.dev/gvisor/pkg/tcpip/internal/tcp                     from gvisor.dev/gvisor/pkg/tcpip/stack+
-        gvisor.dev/gvisor/pkg/tcpip/link/channel                     from tailscale.com/wgengine/netstack
         gvisor.dev/gvisor/pkg/tcpip/network/hash                     from gvisor.dev/gvisor/pkg/tcpip/network/ipv4
         gvisor.dev/gvisor/pkg/tcpip/network/internal/fragmentation   from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
         gvisor.dev/gvisor/pkg/tcpip/network/internal/ip              from gvisor.dev/gvisor/pkg/tcpip/network/ipv4+
@@ -221,6 +225,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         gvisor.dev/gvisor/pkg/tcpip/ports                            from gvisor.dev/gvisor/pkg/tcpip/stack+
         gvisor.dev/gvisor/pkg/tcpip/seqnum                           from gvisor.dev/gvisor/pkg/tcpip/header+
      💣 gvisor.dev/gvisor/pkg/tcpip/stack                            from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
+        gvisor.dev/gvisor/pkg/tcpip/stack/gro                        from tailscale.com/wgengine/netstack/gro
         gvisor.dev/gvisor/pkg/tcpip/transport                        from gvisor.dev/gvisor/pkg/tcpip/transport/icmp+
         gvisor.dev/gvisor/pkg/tcpip/transport/icmp                   from tailscale.com/wgengine/netstack
         gvisor.dev/gvisor/pkg/tcpip/transport/internal/network       from gvisor.dev/gvisor/pkg/tcpip/transport/icmp+
@@ -231,10 +236,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         gvisor.dev/gvisor/pkg/tcpip/transport/tcpconntrack           from gvisor.dev/gvisor/pkg/tcpip/stack
         gvisor.dev/gvisor/pkg/tcpip/transport/udp                    from gvisor.dev/gvisor/pkg/tcpip/adapters/gonet+
         gvisor.dev/gvisor/pkg/waiter                                 from gvisor.dev/gvisor/pkg/context+
-        nhooyr.io/websocket                                          from tailscale.com/control/controlhttp+
-        nhooyr.io/websocket/internal/errd                            from nhooyr.io/websocket
-        nhooyr.io/websocket/internal/util                            from nhooyr.io/websocket
-        nhooyr.io/websocket/internal/xsync                           from nhooyr.io/websocket
         tailscale.com                                                from tailscale.com/version
         tailscale.com/appc                                           from tailscale.com/ipn/ipnlocal
         tailscale.com/atomicfile                                     from tailscale.com/ipn+
@@ -287,6 +288,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/logtail/backoff                                from tailscale.com/cmd/tailscaled+
         tailscale.com/logtail/filch                                  from tailscale.com/log/sockstatlog+
         tailscale.com/metrics                                        from tailscale.com/derp+
+        tailscale.com/net/captivedetection                           from tailscale.com/ipn/ipnlocal+
         tailscale.com/net/connstats                                  from tailscale.com/net/tstun+
         tailscale.com/net/dns                                        from tailscale.com/cmd/tailscaled+
         tailscale.com/net/dns/publicdns                              from tailscale.com/net/dns+
@@ -303,7 +305,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/net/netkernelconf                              from tailscale.com/ipn/ipnlocal
         tailscale.com/net/netknob                                    from tailscale.com/logpolicy+
      💣 tailscale.com/net/netmon                                     from tailscale.com/cmd/tailscaled+
-        tailscale.com/net/netns                                      from tailscale.com/cmd/tailscaled+
+     💣 tailscale.com/net/netns                                      from tailscale.com/cmd/tailscaled+
    W 💣 tailscale.com/net/netstat                                    from tailscale.com/portlist
         tailscale.com/net/netutil                                    from tailscale.com/client/tailscale+
         tailscale.com/net/packet                                     from tailscale.com/net/connstats+
@@ -328,6 +330,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/posture                                        from tailscale.com/ipn/ipnlocal
         tailscale.com/proxymap                                       from tailscale.com/tsd+
      💣 tailscale.com/safesocket                                     from tailscale.com/client/tailscale+
+  LD    tailscale.com/sessionrecording                               from tailscale.com/ssh/tailssh
   LD 💣 tailscale.com/ssh/tailssh                                    from tailscale.com/cmd/tailscaled
         tailscale.com/syncs                                          from tailscale.com/cmd/tailscaled+
         tailscale.com/tailcfg                                        from tailscale.com/client/tailscale+
@@ -335,7 +338,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
   LD    tailscale.com/tempfork/gliderlabs/ssh                        from tailscale.com/ssh/tailssh
         tailscale.com/tempfork/heap                                  from tailscale.com/wgengine/magicsock
         tailscale.com/tka                                            from tailscale.com/client/tailscale+
-   W    tailscale.com/tsconst                                        from tailscale.com/net/netmon
+        tailscale.com/tsconst                                        from tailscale.com/net/netmon+
         tailscale.com/tsd                                            from tailscale.com/cmd/tailscaled+
         tailscale.com/tstime                                         from tailscale.com/control/controlclient+
         tailscale.com/tstime/mono                                    from tailscale.com/net/tstun+
@@ -393,6 +396,8 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/util/singleflight                              from tailscale.com/control/controlclient+
         tailscale.com/util/slicesx                                   from tailscale.com/net/dns/recursive+
         tailscale.com/util/syspolicy                                 from tailscale.com/cmd/tailscaled+
+        tailscale.com/util/syspolicy/internal                        from tailscale.com/util/syspolicy/setting
+        tailscale.com/util/syspolicy/setting                         from tailscale.com/util/syspolicy
         tailscale.com/util/sysresources                              from tailscale.com/wgengine/magicsock
         tailscale.com/util/systemd                                   from tailscale.com/control/controlclient+
         tailscale.com/util/testenv                                   from tailscale.com/ipn/ipnlocal+
@@ -401,6 +406,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/util/vizerror                                  from tailscale.com/tailcfg+
      💣 tailscale.com/util/winutil                                   from tailscale.com/clientupdate+
    W 💣 tailscale.com/util/winutil/authenticode                      from tailscale.com/clientupdate+
+   W 💣 tailscale.com/util/winutil/gp                                from tailscale.com/net/dns
    W    tailscale.com/util/winutil/policy                            from tailscale.com/ipn/ipnlocal
    W 💣 tailscale.com/util/winutil/winenv                            from tailscale.com/hostinfo+
         tailscale.com/util/zstdframe                                 from tailscale.com/control/controlclient+
@@ -414,6 +420,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
      💣 tailscale.com/wgengine/magicsock                             from tailscale.com/ipn/ipnlocal+
         tailscale.com/wgengine/netlog                                from tailscale.com/wgengine
         tailscale.com/wgengine/netstack                              from tailscale.com/cmd/tailscaled
+        tailscale.com/wgengine/netstack/gro                          from tailscale.com/net/tstun+
         tailscale.com/wgengine/router                                from tailscale.com/cmd/tailscaled+
         tailscale.com/wgengine/wgcfg                                 from tailscale.com/ipn/ipnlocal+
         tailscale.com/wgengine/wgcfg/nmcfg                           from tailscale.com/ipn/ipnlocal
@@ -432,7 +439,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         golang.org/x/crypto/hkdf                                     from crypto/tls+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
-        golang.org/x/crypto/poly1305                                 from github.com/tailscale/wireguard-go/device+
+        golang.org/x/crypto/poly1305                                 from github.com/tailscale/wireguard-go/device
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
   LD    golang.org/x/crypto/ssh                                      from github.com/pkg/sftp+
         golang.org/x/exp/constraints                                 from github.com/dblohm7/wingoes/pe+

cmd/tailscaled/tailscaled.go

@@ -35,6 +35,7 @@ import (
 	"tailscale.com/control/controlclient"
 	"tailscale.com/drive/driveimpl"
 	"tailscale.com/envknob"
+	"tailscale.com/hostinfo"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/conffile"
 	"tailscale.com/ipn/ipnlocal"
@@ -154,9 +155,11 @@ var beCLI func() // non-nil if CLI is linked in
 func main() {
 	envknob.PanicIfAnyEnvCheckedInInit()
 	envknob.ApplyDiskConfig()
+	applyIntegrationTestEnvKnob()
 
+	defaultVerbosity := envknob.RegisterInt("TS_LOG_VERBOSITY")
 	printVersion := false
-	flag.IntVar(&args.verbose, "verbose", 0, "log verbosity level; 0 is default, 1 or higher are increasingly verbose")
+	flag.IntVar(&args.verbose, "verbose", defaultVerbosity(), "log verbosity level; 0 is default, 1 or higher are increasingly verbose")
 	flag.BoolVar(&args.cleanUp, "cleanup", false, "clean up system state and exit")
 	flag.StringVar(&args.debug, "debug", "", "listen address ([ip]:port) of optional debug server")
 	flag.StringVar(&args.socksAddr, "socks5-server", "", `optional [ip]:port to run a SOCK5 server (e.g. "localhost:1080")`)
@@ -394,7 +397,7 @@ func run() (err error) {
 	// Always clean up, even if we're going to run the server. This covers cases
 	// such as when a system was rebooted without shutting down, or tailscaled
 	// crashed, and would for example restore system DNS configuration.
-	dns.CleanUp(logf, netMon, args.tunname)
+	dns.CleanUp(logf, netMon, sys.HealthTracker(), args.tunname)
 	router.CleanUp(logf, netMon, args.tunname)
 	// If the cleanUp flag was passed, then exit.
 	if args.cleanUp {
@@ -895,3 +898,24 @@ func dieOnPipeReadErrorOfFD(fd int) {
 	f.Read(make([]byte, 1))
 	os.Exit(1)
 }
+
+// applyIntegrationTestEnvKnob applies the tailscaled.env=... environment
+// variables specified on the Linux kernel command line, if the VM is being
+// run in NATLab integration tests.
+//
+// They're specified as: tailscaled.env=FOO=bar tailscaled.env=BAR=baz
+func applyIntegrationTestEnvKnob() {
+	if runtime.GOOS != "linux" || !hostinfo.IsNATLabGuestVM() {
+		return
+	}
+	cmdLine, _ := os.ReadFile("/proc/cmdline")
+	for _, s := range strings.Fields(string(cmdLine)) {
+		suf, ok := strings.CutPrefix(s, "tailscaled.env=")
+		if !ok {
+			continue
+		}
+		if k, v, ok := strings.Cut(suf, "="); ok {
+			envknob.Setenv(k, v)
+		}
+	}
+}

cmd/tl-longchain/tl-longchain.go

@@ -0,0 +1,93 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Program tl-longchain prints commands to re-sign Tailscale nodes that have
+// long rotation signature chains.
+//
+// There is an implicit limit on the number of rotation signatures that can
+// be chained before the signature becomes too long. This program helps
+// tailnet admins to identify nodes that have signatures with long chains and
+// prints commands to re-sign those node keys with a fresh direct signature.
+// Commands are printed to stdout, while log messages are printed to stderr.
+//
+// Note that the Tailscale client this command is executed on must have
+// ACL visibility to all other nodes to be able to see their signatures.
+// https://tailscale.com/kb/1087/device-visibility
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"time"
+
+	"tailscale.com/client/tailscale"
+	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/tka"
+	"tailscale.com/types/key"
+)
+
+var (
+	flagSocket   = flag.String("socket", "", "custom path to tailscaled socket")
+	maxRotations = flag.Int("rotations", 10, "number of rotation signatures before re-signing (max 16)")
+	showFiltered = flag.Bool("show-filtered", false, "include nodes with invalid signatures")
+)
+
+func main() {
+	flag.Parse()
+
+	lc := tailscale.LocalClient{Socket: *flagSocket}
+	if lc.Socket != "" {
+		lc.UseSocketOnly = true
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	st, err := lc.NetworkLockStatus(ctx)
+	if err != nil {
+		log.Fatalf("could not get Tailnet Lock status: %v", err)
+	}
+	if !st.Enabled {
+		log.Print("Tailnet Lock is not enabled")
+		return
+	}
+	print("Self", *st.NodeKey, *st.NodeKeySignature)
+	if len(st.VisiblePeers) > 0 {
+		log.Print("Visible peers with valid signatures:")
+		for _, peer := range st.VisiblePeers {
+			print(peerInfo(peer), peer.NodeKey, peer.NodeKeySignature)
+		}
+	}
+	if *showFiltered && len(st.FilteredPeers) > 0 {
+		log.Print("Visible peers with invalid signatures:")
+		for _, peer := range st.FilteredPeers {
+			print(peerInfo(peer), peer.NodeKey, peer.NodeKeySignature)
+		}
+	}
+}
+
+// peerInfo returns a string with information about a peer.
+func peerInfo(peer *ipnstate.TKAPeer) string {
+	return fmt.Sprintf("Peer %s (%s) nodeid=%s, current signature kind=%v", peer.Name, peer.TailscaleIPs[0], peer.StableID, peer.NodeKeySignature.SigKind)
+}
+
+// print prints a message about a node key signature and a re-signing command if needed.
+func print(info string, nodeKey key.NodePublic, sig tka.NodeKeySignature) {
+	if l := chainLength(sig); l > *maxRotations {
+		log.Printf("%s: chain length %d, printing command to re-sign", info, l)
+		wrapping, _ := sig.UnverifiedWrappingPublic()
+		fmt.Printf("tailscale lock sign %s %s\n", nodeKey, key.NLPublicFromEd25519Unsafe(wrapping).CLIString())
+	} else {
+		log.Printf("%s: does not need re-signing", info)
+	}
+}
+
+// chainLength returns the length of the rotation signature chain.
+func chainLength(sig tka.NodeKeySignature) int {
+	if sig.SigKind != tka.SigRotation {
+		return 1
+	}
+	return 1 + chainLength(*sig.Nested)
+}

cmd/tsidp/tsidp.go

@@ -7,6 +7,7 @@
 package main
 
 import (
+	"bytes"
 	"context"
 	crand "crypto/rand"
 	"crypto/rsa"
@@ -16,6 +17,7 @@ import (
 	"encoding/binary"
 	"encoding/json"
 	"encoding/pem"
+	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -25,6 +27,7 @@ import (
 	"net/netip"
 	"net/url"
 	"os"
+	"os/signal"
 	"strconv"
 	"strings"
 	"sync"
@@ -35,6 +38,7 @@ import (
 	"tailscale.com/client/tailscale"
 	"tailscale.com/client/tailscale/apitype"
 	"tailscale.com/envknob"
+	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tsnet"
@@ -44,13 +48,22 @@ import (
 	"tailscale.com/util/mak"
 	"tailscale.com/util/must"
 	"tailscale.com/util/rands"
+	"tailscale.com/version"
 )
 
+// ctxConn is a key to look up a net.Conn stored in an HTTP request's context.
+type ctxConn struct{}
+
+// funnelClientsFile is the file where client IDs and secrets for OIDC clients
+// accessing the IDP over Funnel are persisted.
+const funnelClientsFile = "oidc-funnel-clients.json"
+
 var (
 	flagVerbose            = flag.Bool("verbose", false, "be verbose")
 	flagPort               = flag.Int("port", 443, "port to listen on")
 	flagLocalPort          = flag.Int("local-port", -1, "allow requests from localhost")
 	flagUseLocalTailscaled = flag.Bool("use-local-tailscaled", false, "use local tailscaled instead of tsnet")
+	flagFunnel             = flag.Bool("funnel", false, "use Tailscale Funnel to make tsidp available on the public internet")
 )
 
 func main() {
@@ -61,9 +74,11 @@ func main() {
 	}
 
 	var (
-		lc  *tailscale.LocalClient
-		st  *ipnstate.Status
-		err error
+		lc          *tailscale.LocalClient
+		st          *ipnstate.Status
+		err         error
+		watcherChan chan error
+		cleanup     func()
 
 		lns []net.Listener
 	)
@@ -90,6 +105,18 @@ func main() {
 		if !anySuccess {
 			log.Fatalf("failed to listen on any of %v", st.TailscaleIPs)
 		}
+
+		// tailscaled needs to be setting an HTTP header for funneled requests
+		// that older versions don't provide.
+		// TODO(naman): is this the correct check?
+		if *flagFunnel && !version.AtLeast(st.Version, "1.71.0") {
+			log.Fatalf("Local tailscaled not new enough to support -funnel. Update Tailscale or use tsnet mode.")
+		}
+		cleanup, watcherChan, err = serveOnLocalTailscaled(ctx, lc, st, uint16(*flagPort), *flagFunnel)
+		if err != nil {
+			log.Fatalf("could not serve on local tailscaled: %v", err)
+		}
+		defer cleanup()
 	} else {
 		ts := &tsnet.Server{
 			Hostname: "idp",
@@ -105,7 +132,15 @@ func main() {
 		if err != nil {
 			log.Fatalf("getting local client: %v", err)
 		}
-		ln, err := ts.ListenTLS("tcp", fmt.Sprintf(":%d", *flagPort))
+		var ln net.Listener
+		if *flagFunnel {
+			if err := ipn.CheckFunnelAccess(uint16(*flagPort), st.Self); err != nil {
+				log.Fatalf("%v", err)
+			}
+			ln, err = ts.ListenFunnel("tcp", fmt.Sprintf(":%d", *flagPort))
+		} else {
+			ln, err = ts.ListenTLS("tcp", fmt.Sprintf(":%d", *flagPort))
+		}
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -113,13 +148,26 @@ func main() {
 	}
 
 	srv := &idpServer{
-		lc: lc,
+		lc:          lc,
+		funnel:      *flagFunnel,
+		localTSMode: *flagUseLocalTailscaled,
 	}
 	if *flagPort != 443 {
 		srv.serverURL = fmt.Sprintf("https://%s:%d", strings.TrimSuffix(st.Self.DNSName, "."), *flagPort)
 	} else {
 		srv.serverURL = fmt.Sprintf("https://%s", strings.TrimSuffix(st.Self.DNSName, "."))
 	}
+	if *flagFunnel {
+		f, err := os.Open(funnelClientsFile)
+		if err == nil {
+			srv.funnelClients = make(map[string]*funnelClient)
+			if err := json.NewDecoder(f).Decode(&srv.funnelClients); err != nil {
+				log.Fatalf("could not parse %s: %v", funnelClientsFile, err)
+			}
+		} else if !errors.Is(err, os.ErrNotExist) {
+			log.Fatalf("could not open %s: %v", funnelClientsFile, err)
+		}
+	}
 
 	log.Printf("Running tsidp at %s ...", srv.serverURL)
 
@@ -134,35 +182,129 @@ func main() {
 	}
 
 	for _, ln := range lns {
-		go http.Serve(ln, srv)
+		server := http.Server{
+			Handler: srv,
+			ConnContext: func(ctx context.Context, c net.Conn) context.Context {
+				return context.WithValue(ctx, ctxConn{}, c)
+			},
+		}
+		go server.Serve(ln)
 	}
-	select {}
+	// need to catch os.Interrupt, otherwise deferred cleanup code doesn't run
+	exitChan := make(chan os.Signal, 1)
+	signal.Notify(exitChan, os.Interrupt)
+	select {
+	case <-exitChan:
+		log.Printf("interrupt, exiting")
+		return
+	case <-watcherChan:
+		if errors.Is(err, io.EOF) || errors.Is(err, context.Canceled) {
+			log.Printf("watcher closed, exiting")
+			return
+		}
+		log.Fatalf("watcher error: %v", err)
+		return
+	}
+}
+
+// serveOnLocalTailscaled starts a serve session using an already-running
+// tailscaled instead of starting a fresh tsnet server, making something
+// listening on clientDNSName:dstPort accessible over serve/funnel.
+func serveOnLocalTailscaled(ctx context.Context, lc *tailscale.LocalClient, st *ipnstate.Status, dstPort uint16, shouldFunnel bool) (cleanup func(), watcherChan chan error, err error) {
+	// In order to support funneling out in local tailscaled mode, we need
+	// to add a serve config to forward the listeners we bound above and
+	// allow those forwarders to be funneled out.
+	sc, err := lc.GetServeConfig(ctx)
+	if err != nil {
+		return nil, nil, fmt.Errorf("could not get serve config: %v", err)
+	}
+	if sc == nil {
+		sc = new(ipn.ServeConfig)
+	}
+
+	// We watch the IPN bus just to get a session ID. The session expires
+	// when we stop watching the bus, and that auto-deletes the foreground
+	// serve/funnel configs we are creating below.
+	watcher, err := lc.WatchIPNBus(ctx, ipn.NotifyInitialState|ipn.NotifyNoPrivateKeys)
+	if err != nil {
+		return nil, nil, fmt.Errorf("could not set up ipn bus watcher: %v", err)
+	}
+	defer func() {
+		if err != nil {
+			watcher.Close()
+		}
+	}()
+	n, err := watcher.Next()
+	if err != nil {
+		return nil, nil, fmt.Errorf("could not get initial state from ipn bus watcher: %v", err)
+	}
+	if n.SessionID == "" {
+		err = fmt.Errorf("missing sessionID in ipn.Notify")
+		return nil, nil, err
+	}
+	watcherChan = make(chan error)
+	go func() {
+		for {
+			_, err = watcher.Next()
+			if err != nil {
+				watcherChan <- err
+				return
+			}
+		}
+	}()
+
+	// Create a foreground serve config that gets cleaned up when tsidp
+	// exits and the session ID associated with this config is invalidated.
+	foregroundSc := new(ipn.ServeConfig)
+	mak.Set(&sc.Foreground, n.SessionID, foregroundSc)
+	serverURL := strings.TrimSuffix(st.Self.DNSName, ".")
+	fmt.Printf("setting funnel for %s:%v\n", serverURL, dstPort)
+
+	foregroundSc.SetFunnel(serverURL, dstPort, shouldFunnel)
+	foregroundSc.SetWebHandler(&ipn.HTTPHandler{
+		Proxy: fmt.Sprintf("https://%s", net.JoinHostPort(serverURL, strconv.Itoa(int(dstPort)))),
+	}, serverURL, uint16(*flagPort), "/", true)
+	err = lc.SetServeConfig(ctx, sc)
+	if err != nil {
+		return nil, watcherChan, fmt.Errorf("could not set serve config: %v", err)
+	}
+
+	return func() { watcher.Close() }, watcherChan, nil
 }
 
 type idpServer struct {
 	lc          *tailscale.LocalClient
 	loopbackURL string
 	serverURL   string // "https://foo.bar.ts.net"
+	funnel      bool
+	localTSMode bool
 
 	lazyMux        lazy.SyncValue[*http.ServeMux]
 	lazySigningKey lazy.SyncValue[*signingKey]
 	lazySigner     lazy.SyncValue[jose.Signer]
 
-	mu          sync.Mutex              // guards the fields below
-	code        map[string]*authRequest // keyed by random hex
-	accessToken map[string]*authRequest // keyed by random hex
+	mu            sync.Mutex               // guards the fields below
+	code          map[string]*authRequest  // keyed by random hex
+	accessToken   map[string]*authRequest  // keyed by random hex
+	funnelClients map[string]*funnelClient // keyed by client ID
 }
 
 type authRequest struct {
 	// localRP is true if the request is from a relying party running on the
-	// same machine as the idp server. It is mutually exclusive with rpNodeID.
+	// same machine as the idp server. It is mutually exclusive with rpNodeID
+	// and funnelRP.
 	localRP bool
 
 	// rpNodeID is the NodeID of the relying party (who requested the auth, such
 	// as Proxmox or Synology), not the user node who is being authenticated. It
-	// is mutually exclusive with localRP.
+	// is mutually exclusive with localRP and funnelRP.
 	rpNodeID tailcfg.NodeID
 
+	// funnelRP is non-nil if the request is from a relying party outside the
+	// tailnet, via Tailscale Funnel. It is mutually exclusive with rpNodeID
+	// and localRP.
+	funnelRP *funnelClient
+
 	// clientID is the "client_id" sent in the authorized request.
 	clientID string
 
@@ -181,9 +323,12 @@ type authRequest struct {
 	validTill time.Time
 }
 
-func (ar *authRequest) allowRelyingParty(ctx context.Context, remoteAddr string, lc *tailscale.LocalClient) error {
+// allowRelyingParty validates that a relying party identified either by a
+// known remoteAddr or a valid client ID/secret pair is allowed to proceed
+// with the authorization flow associated with this authRequest.
+func (ar *authRequest) allowRelyingParty(r *http.Request, lc *tailscale.LocalClient) error {
 	if ar.localRP {
-		ra, err := netip.ParseAddrPort(remoteAddr)
+		ra, err := netip.ParseAddrPort(r.RemoteAddr)
 		if err != nil {
 			return err
 		}
@@ -192,7 +337,18 @@ func (ar *authRequest) allowRelyingParty(ctx context.Context, remoteAddr string,
 		}
 		return nil
 	}
-	who, err := lc.WhoIs(ctx, remoteAddr)
+	if ar.funnelRP != nil {
+		clientID, clientSecret, ok := r.BasicAuth()
+		if !ok {
+			clientID = r.FormValue("client_id")
+			clientSecret = r.FormValue("client_secret")
+		}
+		if ar.funnelRP.ID != clientID || ar.funnelRP.Secret != clientSecret {
+			return fmt.Errorf("tsidp: invalid client credentials")
+		}
+		return nil
+	}
+	who, err := lc.WhoIs(r.Context(), r.RemoteAddr)
 	if err != nil {
 		return fmt.Errorf("tsidp: error getting WhoIs: %w", err)
 	}
@@ -203,24 +359,60 @@ func (ar *authRequest) allowRelyingParty(ctx context.Context, remoteAddr string,
 }
 
 func (s *idpServer) authorize(w http.ResponseWriter, r *http.Request) {
-	who, err := s.lc.WhoIs(r.Context(), r.RemoteAddr)
+	// This URL is visited by the user who is being authenticated. If they are
+	// visiting the URL over Funnel, that means they are not part of the
+	// tailnet that they are trying to be authenticated for.
+	if isFunnelRequest(r) {
+		http.Error(w, "tsidp: unauthorized", http.StatusUnauthorized)
+		return
+	}
+
+	uq := r.URL.Query()
+
+	redirectURI := uq.Get("redirect_uri")
+	if redirectURI == "" {
+		http.Error(w, "tsidp: must specify redirect_uri", http.StatusBadRequest)
+		return
+	}
+
+	var remoteAddr string
+	if s.localTSMode {
+		// in local tailscaled mode, the local tailscaled is forwarding us
+		// HTTP requests, so reading r.RemoteAddr will just get us our own
+		// address.
+		remoteAddr = r.Header.Get("X-Forwarded-For")
+	} else {
+		remoteAddr = r.RemoteAddr
+	}
+	who, err := s.lc.WhoIs(r.Context(), remoteAddr)
 	if err != nil {
 		log.Printf("Error getting WhoIs: %v", err)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
-	uq := r.URL.Query()
-
 	code := rands.HexString(32)
 	ar := &authRequest{
 		nonce:       uq.Get("nonce"),
 		remoteUser:  who,
-		redirectURI: uq.Get("redirect_uri"),
+		redirectURI: redirectURI,
 		clientID:    uq.Get("client_id"),
 	}
 
-	if r.URL.Path == "/authorize/localhost" {
+	if r.URL.Path == "/authorize/funnel" {
+		s.mu.Lock()
+		c, ok := s.funnelClients[ar.clientID]
+		s.mu.Unlock()
+		if !ok {
+			http.Error(w, "tsidp: invalid client ID", http.StatusBadRequest)
+			return
+		}
+		if ar.redirectURI != c.RedirectURI {
+			http.Error(w, "tsidp: redirect_uri mismatch", http.StatusBadRequest)
+			return
+		}
+		ar.funnelRP = c
+	} else if r.URL.Path == "/authorize/localhost" {
 		ar.localRP = true
 	} else {
 		var ok bool
@@ -237,8 +429,10 @@ func (s *idpServer) authorize(w http.ResponseWriter, r *http.Request) {
 
 	q := make(url.Values)
 	q.Set("code", code)
-	q.Set("state", uq.Get("state"))
-	u := uq.Get("redirect_uri") + "?" + q.Encode()
+	if state := uq.Get("state"); state != "" {
+		q.Set("state", state)
+	}
+	u := redirectURI + "?" + q.Encode()
 	log.Printf("Redirecting to %q", u)
 
 	http.Redirect(w, r, u, http.StatusFound)
@@ -251,6 +445,7 @@ func (s *idpServer) newMux() *http.ServeMux {
 	mux.HandleFunc("/authorize/", s.authorize)
 	mux.HandleFunc("/userinfo", s.serveUserInfo)
 	mux.HandleFunc("/token", s.serveToken)
+	mux.HandleFunc("/clients/", s.serveClients)
 	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		if r.URL.Path == "/" {
 			io.WriteString(w, "<html><body><h1>Tailscale OIDC IdP</h1>")
@@ -284,11 +479,6 @@ func (s *idpServer) serveUserInfo(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "tsidp: invalid token", http.StatusBadRequest)
 		return
 	}
-	if err := ar.allowRelyingParty(r.Context(), r.RemoteAddr, s.lc); err != nil {
-		log.Printf("Error allowing relying party: %v", err)
-		http.Error(w, err.Error(), http.StatusForbidden)
-		return
-	}
 
 	if ar.validTill.Before(time.Now()) {
 		http.Error(w, "tsidp: token expired", http.StatusBadRequest)
@@ -348,7 +538,7 @@ func (s *idpServer) serveToken(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "tsidp: code not found", http.StatusBadRequest)
 		return
 	}
-	if err := ar.allowRelyingParty(r.Context(), r.RemoteAddr, s.lc); err != nil {
+	if err := ar.allowRelyingParty(r, s.lc); err != nil {
 		log.Printf("Error allowing relying party: %v", err)
 		http.Error(w, err.Error(), http.StatusForbidden)
 		return
@@ -581,7 +771,9 @@ func (s *idpServer) serveOpenIDConfig(w http.ResponseWriter, r *http.Request) {
 	}
 	var authorizeEndpoint string
 	rpEndpoint := s.serverURL
-	if who, err := s.lc.WhoIs(r.Context(), r.RemoteAddr); err == nil {
+	if isFunnelRequest(r) {
+		authorizeEndpoint = fmt.Sprintf("%s/authorize/funnel", s.serverURL)
+	} else if who, err := s.lc.WhoIs(r.Context(), r.RemoteAddr); err == nil {
 		authorizeEndpoint = fmt.Sprintf("%s/authorize/%d", s.serverURL, who.Node.ID)
 	} else if ap.Addr().IsLoopback() {
 		rpEndpoint = s.loopbackURL
@@ -611,6 +803,148 @@ func (s *idpServer) serveOpenIDConfig(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+// funnelClient represents an OIDC client/relying party that is accessing the
+// IDP over Funnel.
+type funnelClient struct {
+	ID          string `json:"client_id"`
+	Secret      string `json:"client_secret,omitempty"`
+	Name        string `json:"name,omitempty"`
+	RedirectURI string `json:"redirect_uri"`
+}
+
+// /clients is a privileged endpoint that allows the visitor to create new
+// Funnel-capable OIDC clients, so it is only accessible over the tailnet.
+func (s *idpServer) serveClients(w http.ResponseWriter, r *http.Request) {
+	if isFunnelRequest(r) {
+		http.Error(w, "tsidp: not found", http.StatusNotFound)
+		return
+	}
+
+	path := strings.TrimPrefix(r.URL.Path, "/clients/")
+
+	if path == "new" {
+		s.serveNewClient(w, r)
+		return
+	}
+
+	if path == "" {
+		s.serveGetClientsList(w, r)
+		return
+	}
+
+	s.mu.Lock()
+	c, ok := s.funnelClients[path]
+	s.mu.Unlock()
+	if !ok {
+		http.Error(w, "tsidp: not found", http.StatusNotFound)
+		return
+	}
+
+	switch r.Method {
+	case "DELETE":
+		s.serveDeleteClient(w, r, path)
+	case "GET":
+		json.NewEncoder(w).Encode(&funnelClient{
+			ID:          c.ID,
+			Name:        c.Name,
+			Secret:      "",
+			RedirectURI: c.RedirectURI,
+		})
+	default:
+		http.Error(w, "tsidp: method not allowed", http.StatusMethodNotAllowed)
+	}
+}
+
+func (s *idpServer) serveNewClient(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "POST" {
+		http.Error(w, "tsidp: method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	redirectURI := r.FormValue("redirect_uri")
+	if redirectURI == "" {
+		http.Error(w, "tsidp: must provide redirect_uri", http.StatusBadRequest)
+		return
+	}
+	clientID := rands.HexString(32)
+	clientSecret := rands.HexString(64)
+	newClient := funnelClient{
+		ID:          clientID,
+		Secret:      clientSecret,
+		Name:        r.FormValue("name"),
+		RedirectURI: redirectURI,
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	mak.Set(&s.funnelClients, clientID, &newClient)
+	if err := s.storeFunnelClientsLocked(); err != nil {
+		log.Printf("could not write funnel clients db: %v", err)
+		http.Error(w, "tsidp: could not write funnel clients to db", http.StatusInternalServerError)
+		// delete the new client to avoid inconsistent state between memory
+		// and disk
+		delete(s.funnelClients, clientID)
+		return
+	}
+	json.NewEncoder(w).Encode(newClient)
+}
+
+func (s *idpServer) serveGetClientsList(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "GET" {
+		http.Error(w, "tsidp: method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	s.mu.Lock()
+	redactedClients := make([]funnelClient, 0, len(s.funnelClients))
+	for _, c := range s.funnelClients {
+		redactedClients = append(redactedClients, funnelClient{
+			ID:          c.ID,
+			Name:        c.Name,
+			Secret:      "",
+			RedirectURI: c.RedirectURI,
+		})
+	}
+	s.mu.Unlock()
+	json.NewEncoder(w).Encode(redactedClients)
+}
+
+func (s *idpServer) serveDeleteClient(w http.ResponseWriter, r *http.Request, clientID string) {
+	if r.Method != "DELETE" {
+		http.Error(w, "tsidp: method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.funnelClients == nil {
+		http.Error(w, "tsidp: client not found", http.StatusNotFound)
+		return
+	}
+	if _, ok := s.funnelClients[clientID]; !ok {
+		http.Error(w, "tsidp: client not found", http.StatusNotFound)
+		return
+	}
+	deleted := s.funnelClients[clientID]
+	delete(s.funnelClients, clientID)
+	if err := s.storeFunnelClientsLocked(); err != nil {
+		log.Printf("could not write funnel clients db: %v", err)
+		http.Error(w, "tsidp: could not write funnel clients to db", http.StatusInternalServerError)
+		// restore the deleted value to avoid inconsistent state between memory
+		// and disk
+		s.funnelClients[clientID] = deleted
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// storeFunnelClientsLocked writes the current mapping of OIDC client ID/secret
+// pairs for RPs that access the IDP over funnel. s.mu must be held while
+// calling this.
+func (s *idpServer) storeFunnelClientsLocked() error {
+	var buf bytes.Buffer
+	if err := json.NewEncoder(&buf).Encode(s.funnelClients); err != nil {
+		return err
+	}
+	return os.WriteFile(funnelClientsFile, buf.Bytes(), 0600)
+}
+
 const (
 	minimumRSAKeySize = 2048
 )
@@ -700,3 +1034,24 @@ func parseID[T ~int64](input string) (_ T, ok bool) {
 	}
 	return T(i), true
 }
+
+// isFunnelRequest checks if an HTTP request is coming over Tailscale Funnel.
+func isFunnelRequest(r *http.Request) bool {
+	// If we're funneling through the local tailscaled, it will set this HTTP
+	// header.
+	if r.Header.Get("Tailscale-Funnel-Request") != "" {
+		return true
+	}
+
+	// If the funneled connection is from tsnet, then the net.Conn will be of
+	// type ipn.FunnelConn.
+	netConn := r.Context().Value(ctxConn{})
+	// if the conn is wrapped inside TLS, unwrap it
+	if tlsConn, ok := netConn.(*tls.Conn); ok {
+		netConn = tlsConn.NetConn()
+	}
+	if _, ok := netConn.(*ipn.FunnelConn); ok {
+		return true
+	}
+	return false
+}

cmd/tta/fw_linux.go

@@ -0,0 +1,128 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package main
+
+import (
+	"encoding/binary"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/expr"
+	"tailscale.com/types/ptr"
+)
+
+func init() {
+	addFirewall = addFirewallLinux
+}
+
+func addFirewallLinux() error {
+	c, err := nftables.New()
+	if err != nil {
+		return err
+	}
+
+	// Create a new table
+	table := &nftables.Table{
+		Family: nftables.TableFamilyIPv4, // TableFamilyINet doesn't work (why?. oh well.)
+		Name:   "filter",
+	}
+	c.AddTable(table)
+
+	// Create a new chain for incoming traffic
+	inputChain := &nftables.Chain{
+		Name:     "input",
+		Table:    table,
+		Type:     nftables.ChainTypeFilter,
+		Hooknum:  nftables.ChainHookInput,
+		Priority: nftables.ChainPriorityFilter,
+		Policy:   ptr.To(nftables.ChainPolicyDrop),
+	}
+	c.AddChain(inputChain)
+
+	// Allow traffic from the loopback interface
+	c.AddRule(&nftables.Rule{
+		Table: table,
+		Chain: inputChain,
+		Exprs: []expr.Any{
+			&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+			&expr.Cmp{
+				Op:       expr.CmpOpEq,
+				Register: 1,
+				Data:     []byte("lo"),
+			},
+			&expr.Verdict{
+				Kind: expr.VerdictAccept,
+			},
+		},
+	})
+
+	// Accept established and related connections
+	c.AddRule(&nftables.Rule{
+		Table: table,
+		Chain: inputChain,
+		Exprs: []expr.Any{
+			&expr.Ct{
+				Register: 1,
+				Key:      expr.CtKeySTATE,
+			},
+			&expr.Bitwise{
+				SourceRegister: 1,
+				DestRegister:   1,
+				Len:            4,
+				Mask:           binary.NativeEndian.AppendUint32(nil, 0x06), // CT_STATE_BIT_ESTABLISHED | CT_STATE_BIT_RELATED
+				Xor:            binary.NativeEndian.AppendUint32(nil, 0),
+			},
+			&expr.Cmp{
+				Op:       expr.CmpOpNeq,
+				Register: 1,
+				Data:     binary.NativeEndian.AppendUint32(nil, 0x00),
+			},
+			&expr.Verdict{
+				Kind: expr.VerdictAccept,
+			},
+		},
+	})
+
+	// Allow TCP packets in that don't have the SYN bit set, even if they're not
+	// ESTABLISHED or RELATED. This is because the test suite gets TCP
+	// connections up & idle (for HTTP) before it conditionally installs these
+	// firewall rules. But because conntrack wasn't previously active, existing
+	// TCP flows aren't ESTABLISHED and get dropped. So this rule allows
+	// previously established TCP connections that predates the firewall rules
+	// to continue working, as they don't have conntrack state.
+	c.AddRule(&nftables.Rule{
+		Table: table,
+		Chain: inputChain,
+		Exprs: []expr.Any{
+			&expr.Meta{Key: expr.MetaKeyL4PROTO, Register: 1},
+			&expr.Cmp{
+				Op:       expr.CmpOpEq,
+				Register: 1,
+				Data:     []byte{0x06}, // TCP
+			},
+			&expr.Payload{ // get TCP flags
+				DestRegister: 1,
+				Base:         2,
+				Offset:       13, // flags
+				Len:          1,
+			},
+			&expr.Bitwise{
+				SourceRegister: 1,
+				DestRegister:   1,
+				Len:            1,
+				Mask:           []byte{2}, // TCP_SYN
+				Xor:            []byte{0},
+			},
+			&expr.Cmp{
+				Op:       expr.CmpOpNeq,
+				Register: 1,
+				Data:     []byte{2}, // TCP_SYN
+			},
+			&expr.Verdict{
+				Kind: expr.VerdictAccept,
+			},
+		},
+	})
+
+	return c.Flush()
+}

cmd/tta/tta.go

@@ -0,0 +1,238 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// The tta server is the Tailscale Test Agent.
+//
+// It runs on each Tailscale node being integration tested and permits the test
+// harness to control the node. It connects out to the test drver (rather than
+// accepting any TCP connections inbound, which might be blocked depending on
+// the scenario being tested) and then the test driver turns the TCP connection
+// around and sends request back.
+package main
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+	"sync"
+	"time"
+
+	"tailscale.com/client/tailscale"
+	"tailscale.com/hostinfo"
+	"tailscale.com/util/must"
+	"tailscale.com/util/set"
+	"tailscale.com/version/distro"
+)
+
+var (
+	driverAddr = flag.String("driver", "test-driver.tailscale:8008", "address of the test driver; by default we use the DNS name test-driver.tailscale which is special cased in the emulated network's DNS server")
+)
+
+func absify(cmd string) string {
+	if distro.Get() == distro.Gokrazy && !strings.Contains(cmd, "/") {
+		return "/user/" + cmd
+	}
+	return cmd
+}
+
+func serveCmd(w http.ResponseWriter, cmd string, args ...string) {
+	log.Printf("Got serveCmd for %q %v", cmd, args)
+	out, err := exec.Command(absify(cmd), args...).CombinedOutput()
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	if err != nil {
+		w.Header().Set("Exec-Err", err.Error())
+		w.WriteHeader(500)
+		log.Printf("Err on serveCmd for %q %v, %d bytes of output: %v", cmd, args, len(out), err)
+	} else {
+		log.Printf("Did serveCmd for %q %v, %d bytes of output", cmd, args, len(out))
+	}
+	w.Write(out)
+}
+
+type localClientRoundTripper struct {
+	lc tailscale.LocalClient
+}
+
+func (rt *localClientRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	req = req.Clone(req.Context())
+	req.RequestURI = ""
+	return rt.lc.DoLocalRequest(req)
+}
+
+func main() {
+	if distro.Get() == distro.Gokrazy {
+		if !hostinfo.IsNATLabGuestVM() {
+			// "Exiting immediately with status code 0 when the
+			// GOKRAZY_FIRST_START=1 environment variable is set means “don’t
+			// start the program on boot”"
+			return
+		}
+	}
+	flag.Parse()
+
+	if distro.Get() == distro.Gokrazy {
+		nsRx := regexp.MustCompile(`(?m)^nameserver (.*)`)
+		for t := time.Now(); time.Since(t) < 10*time.Second; time.Sleep(10 * time.Millisecond) {
+			all, _ := os.ReadFile("/etc/resolv.conf")
+			if nsRx.Match(all) {
+				break
+			}
+		}
+	}
+
+	logc, err := net.Dial("tcp", "9.9.9.9:124")
+	if err == nil {
+		log.SetOutput(logc)
+	}
+
+	log.Printf("Tailscale Test Agent running.")
+
+	gokRP := httputil.NewSingleHostReverseProxy(must.Get(url.Parse("http://gokrazy")))
+	gokRP.Transport = &http.Transport{
+		DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+			if network != "tcp" {
+				return nil, errors.New("unexpected network")
+			}
+			if addr != "gokrazy:80" {
+				return nil, errors.New("unexpected addr")
+			}
+			var d net.Dialer
+			return d.DialContext(ctx, "unix", "/run/gokrazy-http.sock")
+		},
+	}
+
+	var ttaMux http.ServeMux // agent mux
+	var serveMux http.ServeMux
+	serveMux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		if r.Header.Get("X-TTA-GoKrazy") == "1" {
+			gokRP.ServeHTTP(w, r)
+			return
+		}
+		ttaMux.ServeHTTP(w, r)
+	})
+	var hs http.Server
+	hs.Handler = &serveMux
+	var (
+		stMu   sync.Mutex
+		newSet = set.Set[net.Conn]{} // conns in StateNew
+	)
+	needConnCh := make(chan bool, 1)
+	hs.ConnState = func(c net.Conn, s http.ConnState) {
+		stMu.Lock()
+		defer stMu.Unlock()
+		oldLen := len(newSet)
+		switch s {
+		case http.StateNew:
+			newSet.Add(c)
+		default:
+			newSet.Delete(c)
+		}
+		if oldLen != 0 && len(newSet) == 0 {
+			select {
+			case needConnCh <- true:
+			default:
+			}
+		}
+	}
+	conns := make(chan net.Conn, 1)
+
+	lcRP := httputil.NewSingleHostReverseProxy(must.Get(url.Parse("http://local-tailscaled.sock")))
+	lcRP.Transport = new(localClientRoundTripper)
+	ttaMux.HandleFunc("/localapi/", func(w http.ResponseWriter, r *http.Request) {
+		log.Printf("Got localapi request: %v", r.URL)
+		t0 := time.Now()
+		lcRP.ServeHTTP(w, r)
+		log.Printf("Did localapi request in %v: %v", time.Since(t0).Round(time.Millisecond), r.URL)
+	})
+
+	ttaMux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		io.WriteString(w, "TTA\n")
+		return
+	})
+	ttaMux.HandleFunc("/up", func(w http.ResponseWriter, r *http.Request) {
+		serveCmd(w, "tailscale", "up", "--login-server=http://control.tailscale")
+	})
+	ttaMux.HandleFunc("/fw", addFirewallHandler)
+
+	go hs.Serve(chanListener(conns))
+
+	// For doing agent operations locally from gokrazy:
+	// (e.g. with "wget -O - localhost:8123/fw")
+	go func() {
+		err := http.ListenAndServe("127.0.0.1:8123", &ttaMux)
+		if err != nil {
+			log.Fatalf("ListenAndServe: %v", err)
+		}
+	}()
+
+	var lastErr string
+	needConnCh <- true
+	for {
+		<-needConnCh
+		c, err := connect()
+		if err != nil {
+			s := err.Error()
+			if s != lastErr {
+				log.Printf("Connect failure: %v", s)
+			}
+			lastErr = s
+			time.Sleep(time.Second)
+			continue
+		}
+		conns <- c
+	}
+}
+
+func connect() (net.Conn, error) {
+	c, err := net.Dial("tcp", *driverAddr)
+	if err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+type chanListener <-chan net.Conn
+
+func (cl chanListener) Accept() (net.Conn, error) {
+	c, ok := <-cl
+	if !ok {
+		return nil, errors.New("closed")
+	}
+	return c, nil
+}
+
+func (cl chanListener) Close() error {
+	return nil
+}
+
+func (cl chanListener) Addr() net.Addr {
+	return &net.TCPAddr{
+		IP:   net.ParseIP("52.0.0.34"), // TS..DR(iver)
+		Port: 123,
+	}
+}
+
+func addFirewallHandler(w http.ResponseWriter, r *http.Request) {
+	if addFirewall == nil {
+		http.Error(w, "firewall not supported", 500)
+		return
+	}
+	err := addFirewall()
+	if err != nil {
+		http.Error(w, err.Error(), 500)
+		return
+	}
+	io.WriteString(w, "OK\n")
+}
+
+var addFirewall func() error // set by fw_linux.go

cmd/viewer/tests/tests.go

@@ -7,9 +7,13 @@ package tests
 import (
 	"fmt"
 	"net/netip"
+
+	"golang.org/x/exp/constraints"
+	"tailscale.com/types/ptr"
+	"tailscale.com/types/views"
 )
 
-//go:generate go run tailscale.com/cmd/viewer --type=StructWithPtrs,StructWithoutPtrs,Map,StructWithSlices,OnlyGetClone,StructWithEmbedded --clone-only-type=OnlyGetClone
+//go:generate go run tailscale.com/cmd/viewer --type=StructWithPtrs,StructWithoutPtrs,Map,StructWithSlices,OnlyGetClone,StructWithEmbedded,GenericIntStruct,GenericNoPtrsStruct,GenericCloneableStruct,StructWithContainers --clone-only-type=OnlyGetClone
 
 type StructWithoutPtrs struct {
 	Int int
@@ -25,12 +29,12 @@ type Map struct {
 	SlicesWithPtrs      map[string][]*StructWithPtrs
 	SlicesWithoutPtrs   map[string][]*StructWithoutPtrs
 	StructWithoutPtrKey map[StructWithoutPtrs]int `json:"-"`
+	StructWithPtr       map[string]StructWithPtrs
 
 	// Unsupported views.
 	SliceIntPtr      map[string][]*int
 	PointerKey       map[*string]int        `json:"-"`
 	StructWithPtrKey map[StructWithPtrs]int `json:"-"`
-	StructWithPtr    map[string]StructWithPtrs
 }
 
 type StructWithPtrs struct {
@@ -50,12 +54,14 @@ type StructWithSlices struct {
 	Values         []StructWithoutPtrs
 	ValuePointers  []*StructWithoutPtrs
 	StructPointers []*StructWithPtrs
-	Structs        []StructWithPtrs
-	Ints           []*int
 
 	Slice    []string
 	Prefixes []netip.Prefix
 	Data     []byte
+
+	// Unsupported views.
+	Structs []StructWithPtrs
+	Ints    []*int
 }
 
 type OnlyGetClone struct {
@@ -66,3 +72,133 @@ type StructWithEmbedded struct {
 	A *StructWithPtrs
 	StructWithSlices
 }
+
+type GenericIntStruct[T constraints.Integer] struct {
+	Value   T
+	Pointer *T
+	Slice   []T
+	Map     map[string]T
+
+	// Unsupported views.
+	PtrSlice    []*T
+	PtrKeyMap   map[*T]string `json:"-"`
+	PtrValueMap map[string]*T
+	SliceMap    map[string][]T
+}
+
+type BasicType interface {
+	~bool | constraints.Integer | constraints.Float | constraints.Complex | ~string
+}
+
+type GenericNoPtrsStruct[T StructWithoutPtrs | netip.Prefix | BasicType] struct {
+	Value   T
+	Pointer *T
+	Slice   []T
+	Map     map[string]T
+
+	// Unsupported views.
+	PtrSlice    []*T
+	PtrKeyMap   map[*T]string `json:"-"`
+	PtrValueMap map[string]*T
+	SliceMap    map[string][]T
+}
+
+type GenericCloneableStruct[T views.ViewCloner[T, V], V views.StructView[T]] struct {
+	Value T
+	Slice []T
+	Map   map[string]T
+
+	// Unsupported views.
+	Pointer     *T
+	PtrSlice    []*T
+	PtrKeyMap   map[*T]string `json:"-"`
+	PtrValueMap map[string]*T
+	SliceMap    map[string][]T
+}
+
+// Container is a pre-defined container type, such as a collection, an optional
+// value or a generic wrapper.
+type Container[T any] struct {
+	Item T
+}
+
+func (c *Container[T]) Clone() *Container[T] {
+	if c == nil {
+		return nil
+	}
+	if cloner, ok := any(c.Item).(views.Cloner[T]); ok {
+		return &Container[T]{cloner.Clone()}
+	}
+	if !views.ContainsPointers[T]() {
+		return ptr.To(*c)
+	}
+	panic(fmt.Errorf("%T contains pointers, but is not cloneable", c.Item))
+}
+
+// ContainerView is a pre-defined readonly view of a Container[T].
+type ContainerView[T views.ViewCloner[T, V], V views.StructView[T]] struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *Container[T]
+}
+
+func (cv ContainerView[T, V]) Item() V {
+	return cv.ж.Item.View()
+}
+
+func ContainerViewOf[T views.ViewCloner[T, V], V views.StructView[T]](c *Container[T]) ContainerView[T, V] {
+	return ContainerView[T, V]{c}
+}
+
+// MapContainer is a predefined map-like container type.
+// Unlike [Container], it has two type parameters, where the value
+// is the second parameter.
+type MapContainer[K comparable, V views.Cloner[V]] struct {
+	Items map[K]V
+}
+
+func (c *MapContainer[K, V]) Clone() *MapContainer[K, V] {
+	if c == nil {
+		return nil
+	}
+	var m map[K]V
+	if c.Items != nil {
+		m = make(map[K]V, len(c.Items))
+		for i := range m {
+			m[i] = c.Items[i].Clone()
+		}
+	}
+	return &MapContainer[K, V]{m}
+}
+
+// MapContainerView is a pre-defined readonly view of a [MapContainer][K, T].
+type MapContainerView[K comparable, T views.ViewCloner[T, V], V views.StructView[T]] struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *MapContainer[K, T]
+}
+
+func (cv MapContainerView[K, T, V]) Items() views.MapFn[K, T, V] {
+	return views.MapFnOf(cv.ж.Items, func(t T) V { return t.View() })
+}
+
+func MapContainerViewOf[K comparable, T views.ViewCloner[T, V], V views.StructView[T]](c *MapContainer[K, T]) MapContainerView[K, T, V] {
+	return MapContainerView[K, T, V]{c}
+}
+
+type GenericBasicStruct[T BasicType] struct {
+	Value T
+}
+
+type StructWithContainers struct {
+	IntContainer              Container[int]
+	CloneableContainer        Container[*StructWithPtrs]
+	BasicGenericContainer     Container[GenericBasicStruct[int]]
+	CloneableGenericContainer Container[*GenericNoPtrsStruct[int]]
+	CloneableMap              MapContainer[int, *StructWithPtrs]
+	CloneableGenericMap       MapContainer[int, *GenericNoPtrsStruct[int]]
+}

cmd/viewer/tests/tests_clone.go

@@ -9,7 +9,9 @@ import (
 	"maps"
 	"net/netip"
 
+	"golang.org/x/exp/constraints"
 	"tailscale.com/types/ptr"
+	"tailscale.com/types/views"
 )
 
 // Clone makes a deep copy of StructWithPtrs.
@@ -71,13 +73,21 @@ func (src *Map) Clone() *Map {
 	if dst.StructPtrWithPtr != nil {
 		dst.StructPtrWithPtr = map[string]*StructWithPtrs{}
 		for k, v := range src.StructPtrWithPtr {
-			dst.StructPtrWithPtr[k] = v.Clone()
+			if v == nil {
+				dst.StructPtrWithPtr[k] = nil
+			} else {
+				dst.StructPtrWithPtr[k] = v.Clone()
+			}
 		}
 	}
 	if dst.StructPtrWithoutPtr != nil {
 		dst.StructPtrWithoutPtr = map[string]*StructWithoutPtrs{}
 		for k, v := range src.StructPtrWithoutPtr {
-			dst.StructPtrWithoutPtr[k] = v.Clone()
+			if v == nil {
+				dst.StructPtrWithoutPtr[k] = nil
+			} else {
+				dst.StructPtrWithoutPtr[k] = ptr.To(*v)
+			}
 		}
 	}
 	dst.StructWithoutPtr = maps.Clone(src.StructWithoutPtr)
@@ -94,6 +104,12 @@ func (src *Map) Clone() *Map {
 		}
 	}
 	dst.StructWithoutPtrKey = maps.Clone(src.StructWithoutPtrKey)
+	if dst.StructWithPtr != nil {
+		dst.StructWithPtr = map[string]StructWithPtrs{}
+		for k, v := range src.StructWithPtr {
+			dst.StructWithPtr[k] = *(v.Clone())
+		}
+	}
 	if dst.SliceIntPtr != nil {
 		dst.SliceIntPtr = map[string][]*int{}
 		for k := range src.SliceIntPtr {
@@ -102,12 +118,6 @@ func (src *Map) Clone() *Map {
 	}
 	dst.PointerKey = maps.Clone(src.PointerKey)
 	dst.StructWithPtrKey = maps.Clone(src.StructWithPtrKey)
-	if dst.StructWithPtr != nil {
-		dst.StructWithPtr = map[string]StructWithPtrs{}
-		for k, v := range src.StructWithPtr {
-			dst.StructWithPtr[k] = *(v.Clone())
-		}
-	}
 	return dst
 }
 
@@ -121,10 +131,10 @@ var _MapCloneNeedsRegeneration = Map(struct {
 	SlicesWithPtrs      map[string][]*StructWithPtrs
 	SlicesWithoutPtrs   map[string][]*StructWithoutPtrs
 	StructWithoutPtrKey map[StructWithoutPtrs]int
+	StructWithPtr       map[string]StructWithPtrs
 	SliceIntPtr         map[string][]*int
 	PointerKey          map[*string]int
 	StructWithPtrKey    map[StructWithPtrs]int
-	StructWithPtr       map[string]StructWithPtrs
 }{})
 
 // Clone makes a deep copy of StructWithSlices.
@@ -139,15 +149,26 @@ func (src *StructWithSlices) Clone() *StructWithSlices {
 	if src.ValuePointers != nil {
 		dst.ValuePointers = make([]*StructWithoutPtrs, len(src.ValuePointers))
 		for i := range dst.ValuePointers {
-			dst.ValuePointers[i] = src.ValuePointers[i].Clone()
+			if src.ValuePointers[i] == nil {
+				dst.ValuePointers[i] = nil
+			} else {
+				dst.ValuePointers[i] = ptr.To(*src.ValuePointers[i])
+			}
 		}
 	}
 	if src.StructPointers != nil {
 		dst.StructPointers = make([]*StructWithPtrs, len(src.StructPointers))
 		for i := range dst.StructPointers {
-			dst.StructPointers[i] = src.StructPointers[i].Clone()
+			if src.StructPointers[i] == nil {
+				dst.StructPointers[i] = nil
+			} else {
+				dst.StructPointers[i] = src.StructPointers[i].Clone()
+			}
 		}
 	}
+	dst.Slice = append(src.Slice[:0:0], src.Slice...)
+	dst.Prefixes = append(src.Prefixes[:0:0], src.Prefixes...)
+	dst.Data = append(src.Data[:0:0], src.Data...)
 	if src.Structs != nil {
 		dst.Structs = make([]StructWithPtrs, len(src.Structs))
 		for i := range dst.Structs {
@@ -164,9 +185,6 @@ func (src *StructWithSlices) Clone() *StructWithSlices {
 			}
 		}
 	}
-	dst.Slice = append(src.Slice[:0:0], src.Slice...)
-	dst.Prefixes = append(src.Prefixes[:0:0], src.Prefixes...)
-	dst.Data = append(src.Data[:0:0], src.Data...)
 	return dst
 }
 
@@ -175,11 +193,11 @@ var _StructWithSlicesCloneNeedsRegeneration = StructWithSlices(struct {
 	Values         []StructWithoutPtrs
 	ValuePointers  []*StructWithoutPtrs
 	StructPointers []*StructWithPtrs
-	Structs        []StructWithPtrs
-	Ints           []*int
 	Slice          []string
 	Prefixes       []netip.Prefix
 	Data           []byte
+	Structs        []StructWithPtrs
+	Ints           []*int
 }{})
 
 // Clone makes a deep copy of OnlyGetClone.
@@ -216,3 +234,210 @@ var _StructWithEmbeddedCloneNeedsRegeneration = StructWithEmbedded(struct {
 	A *StructWithPtrs
 	StructWithSlices
 }{})
+
+// Clone makes a deep copy of GenericIntStruct.
+// The result aliases no memory with the original.
+func (src *GenericIntStruct[T]) Clone() *GenericIntStruct[T] {
+	if src == nil {
+		return nil
+	}
+	dst := new(GenericIntStruct[T])
+	*dst = *src
+	if dst.Pointer != nil {
+		dst.Pointer = ptr.To(*src.Pointer)
+	}
+	dst.Slice = append(src.Slice[:0:0], src.Slice...)
+	dst.Map = maps.Clone(src.Map)
+	if src.PtrSlice != nil {
+		dst.PtrSlice = make([]*T, len(src.PtrSlice))
+		for i := range dst.PtrSlice {
+			if src.PtrSlice[i] == nil {
+				dst.PtrSlice[i] = nil
+			} else {
+				dst.PtrSlice[i] = ptr.To(*src.PtrSlice[i])
+			}
+		}
+	}
+	dst.PtrKeyMap = maps.Clone(src.PtrKeyMap)
+	if dst.PtrValueMap != nil {
+		dst.PtrValueMap = map[string]*T{}
+		for k, v := range src.PtrValueMap {
+			if v == nil {
+				dst.PtrValueMap[k] = nil
+			} else {
+				dst.PtrValueMap[k] = ptr.To(*v)
+			}
+		}
+	}
+	if dst.SliceMap != nil {
+		dst.SliceMap = map[string][]T{}
+		for k := range src.SliceMap {
+			dst.SliceMap[k] = append([]T{}, src.SliceMap[k]...)
+		}
+	}
+	return dst
+}
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericIntStructCloneNeedsRegeneration[T constraints.Integer](GenericIntStruct[T]) {
+	_GenericIntStructCloneNeedsRegeneration(struct {
+		Value       T
+		Pointer     *T
+		Slice       []T
+		Map         map[string]T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}
+
+// Clone makes a deep copy of GenericNoPtrsStruct.
+// The result aliases no memory with the original.
+func (src *GenericNoPtrsStruct[T]) Clone() *GenericNoPtrsStruct[T] {
+	if src == nil {
+		return nil
+	}
+	dst := new(GenericNoPtrsStruct[T])
+	*dst = *src
+	if dst.Pointer != nil {
+		dst.Pointer = ptr.To(*src.Pointer)
+	}
+	dst.Slice = append(src.Slice[:0:0], src.Slice...)
+	dst.Map = maps.Clone(src.Map)
+	if src.PtrSlice != nil {
+		dst.PtrSlice = make([]*T, len(src.PtrSlice))
+		for i := range dst.PtrSlice {
+			if src.PtrSlice[i] == nil {
+				dst.PtrSlice[i] = nil
+			} else {
+				dst.PtrSlice[i] = ptr.To(*src.PtrSlice[i])
+			}
+		}
+	}
+	dst.PtrKeyMap = maps.Clone(src.PtrKeyMap)
+	if dst.PtrValueMap != nil {
+		dst.PtrValueMap = map[string]*T{}
+		for k, v := range src.PtrValueMap {
+			if v == nil {
+				dst.PtrValueMap[k] = nil
+			} else {
+				dst.PtrValueMap[k] = ptr.To(*v)
+			}
+		}
+	}
+	if dst.SliceMap != nil {
+		dst.SliceMap = map[string][]T{}
+		for k := range src.SliceMap {
+			dst.SliceMap[k] = append([]T{}, src.SliceMap[k]...)
+		}
+	}
+	return dst
+}
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericNoPtrsStructCloneNeedsRegeneration[T StructWithoutPtrs | netip.Prefix | BasicType](GenericNoPtrsStruct[T]) {
+	_GenericNoPtrsStructCloneNeedsRegeneration(struct {
+		Value       T
+		Pointer     *T
+		Slice       []T
+		Map         map[string]T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}
+
+// Clone makes a deep copy of GenericCloneableStruct.
+// The result aliases no memory with the original.
+func (src *GenericCloneableStruct[T, V]) Clone() *GenericCloneableStruct[T, V] {
+	if src == nil {
+		return nil
+	}
+	dst := new(GenericCloneableStruct[T, V])
+	*dst = *src
+	dst.Value = src.Value.Clone()
+	if src.Slice != nil {
+		dst.Slice = make([]T, len(src.Slice))
+		for i := range dst.Slice {
+			dst.Slice[i] = src.Slice[i].Clone()
+		}
+	}
+	if dst.Map != nil {
+		dst.Map = map[string]T{}
+		for k, v := range src.Map {
+			dst.Map[k] = v.Clone()
+		}
+	}
+	if dst.Pointer != nil {
+		dst.Pointer = ptr.To((*src.Pointer).Clone())
+	}
+	if src.PtrSlice != nil {
+		dst.PtrSlice = make([]*T, len(src.PtrSlice))
+		for i := range dst.PtrSlice {
+			if src.PtrSlice[i] == nil {
+				dst.PtrSlice[i] = nil
+			} else {
+				dst.PtrSlice[i] = ptr.To((*src.PtrSlice[i]).Clone())
+			}
+		}
+	}
+	dst.PtrKeyMap = maps.Clone(src.PtrKeyMap)
+	if dst.PtrValueMap != nil {
+		dst.PtrValueMap = map[string]*T{}
+		for k, v := range src.PtrValueMap {
+			if v == nil {
+				dst.PtrValueMap[k] = nil
+			} else {
+				dst.PtrValueMap[k] = ptr.To((*v).Clone())
+			}
+		}
+	}
+	if dst.SliceMap != nil {
+		dst.SliceMap = map[string][]T{}
+		for k := range src.SliceMap {
+			dst.SliceMap[k] = append([]T{}, src.SliceMap[k]...)
+		}
+	}
+	return dst
+}
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericCloneableStructCloneNeedsRegeneration[T views.ViewCloner[T, V], V views.StructView[T]](GenericCloneableStruct[T, V]) {
+	_GenericCloneableStructCloneNeedsRegeneration(struct {
+		Value       T
+		Slice       []T
+		Map         map[string]T
+		Pointer     *T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}
+
+// Clone makes a deep copy of StructWithContainers.
+// The result aliases no memory with the original.
+func (src *StructWithContainers) Clone() *StructWithContainers {
+	if src == nil {
+		return nil
+	}
+	dst := new(StructWithContainers)
+	*dst = *src
+	dst.CloneableContainer = *src.CloneableContainer.Clone()
+	dst.CloneableGenericContainer = *src.CloneableGenericContainer.Clone()
+	dst.CloneableMap = *src.CloneableMap.Clone()
+	dst.CloneableGenericMap = *src.CloneableGenericMap.Clone()
+	return dst
+}
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _StructWithContainersCloneNeedsRegeneration = StructWithContainers(struct {
+	IntContainer              Container[int]
+	CloneableContainer        Container[*StructWithPtrs]
+	BasicGenericContainer     Container[GenericBasicStruct[int]]
+	CloneableGenericContainer Container[*GenericNoPtrsStruct[int]]
+	CloneableMap              MapContainer[int, *StructWithPtrs]
+	CloneableGenericMap       MapContainer[int, *GenericNoPtrsStruct[int]]
+}{})

cmd/viewer/tests/tests_view.go

@@ -10,10 +10,11 @@ import (
 	"errors"
 	"net/netip"
 
+	"golang.org/x/exp/constraints"
 	"tailscale.com/types/views"
 )
 
-//go:generate go run tailscale.com/cmd/cloner  -clonefunc=false -type=StructWithPtrs,StructWithoutPtrs,Map,StructWithSlices,OnlyGetClone,StructWithEmbedded
+//go:generate go run tailscale.com/cmd/cloner  -clonefunc=false -type=StructWithPtrs,StructWithoutPtrs,Map,StructWithSlices,OnlyGetClone,StructWithEmbedded,GenericIntStruct,GenericNoPtrsStruct,GenericCloneableStruct,StructWithContainers
 
 // View returns a readonly view of StructWithPtrs.
 func (p *StructWithPtrs) View() StructWithPtrsView {
@@ -221,15 +222,15 @@ func (v MapView) SlicesWithoutPtrs() views.MapFn[string, []*StructWithoutPtrs, v
 func (v MapView) StructWithoutPtrKey() views.Map[StructWithoutPtrs, int] {
 	return views.MapOf(v.ж.StructWithoutPtrKey)
 }
-func (v MapView) SliceIntPtr() map[string][]*int           { panic("unsupported") }
-func (v MapView) PointerKey() map[*string]int              { panic("unsupported") }
-func (v MapView) StructWithPtrKey() map[StructWithPtrs]int { panic("unsupported") }
 
 func (v MapView) StructWithPtr() views.MapFn[string, StructWithPtrs, StructWithPtrsView] {
 	return views.MapFnOf(v.ж.StructWithPtr, func(t StructWithPtrs) StructWithPtrsView {
 		return t.View()
 	})
 }
+func (v MapView) SliceIntPtr() map[string][]*int           { panic("unsupported") }
+func (v MapView) PointerKey() map[*string]int              { panic("unsupported") }
+func (v MapView) StructWithPtrKey() map[StructWithPtrs]int { panic("unsupported") }
 
 // A compilation failure here means this code must be regenerated, with the command at the top of this file.
 var _MapViewNeedsRegeneration = Map(struct {
@@ -241,10 +242,10 @@ var _MapViewNeedsRegeneration = Map(struct {
 	SlicesWithPtrs      map[string][]*StructWithPtrs
 	SlicesWithoutPtrs   map[string][]*StructWithoutPtrs
 	StructWithoutPtrKey map[StructWithoutPtrs]int
+	StructWithPtr       map[string]StructWithPtrs
 	SliceIntPtr         map[string][]*int
 	PointerKey          map[*string]int
 	StructWithPtrKey    map[StructWithPtrs]int
-	StructWithPtr       map[string]StructWithPtrs
 }{})
 
 // View returns a readonly view of StructWithSlices.
@@ -301,24 +302,24 @@ func (v StructWithSlicesView) ValuePointers() views.SliceView[*StructWithoutPtrs
 func (v StructWithSlicesView) StructPointers() views.SliceView[*StructWithPtrs, StructWithPtrsView] {
 	return views.SliceOfViews[*StructWithPtrs, StructWithPtrsView](v.ж.StructPointers)
 }
-func (v StructWithSlicesView) Structs() StructWithPtrs    { panic("unsupported") }
-func (v StructWithSlicesView) Ints() *int                 { panic("unsupported") }
 func (v StructWithSlicesView) Slice() views.Slice[string] { return views.SliceOf(v.ж.Slice) }
 func (v StructWithSlicesView) Prefixes() views.Slice[netip.Prefix] {
 	return views.SliceOf(v.ж.Prefixes)
 }
 func (v StructWithSlicesView) Data() views.ByteSlice[[]byte] { return views.ByteSliceOf(v.ж.Data) }
+func (v StructWithSlicesView) Structs() StructWithPtrs       { panic("unsupported") }
+func (v StructWithSlicesView) Ints() *int                    { panic("unsupported") }
 
 // A compilation failure here means this code must be regenerated, with the command at the top of this file.
 var _StructWithSlicesViewNeedsRegeneration = StructWithSlices(struct {
 	Values         []StructWithoutPtrs
 	ValuePointers  []*StructWithoutPtrs
 	StructPointers []*StructWithPtrs
-	Structs        []StructWithPtrs
-	Ints           []*int
 	Slice          []string
 	Prefixes       []netip.Prefix
 	Data           []byte
+	Structs        []StructWithPtrs
+	Ints           []*int
 }{})
 
 // View returns a readonly view of StructWithEmbedded.
@@ -376,3 +377,302 @@ var _StructWithEmbeddedViewNeedsRegeneration = StructWithEmbedded(struct {
 	A *StructWithPtrs
 	StructWithSlices
 }{})
+
+// View returns a readonly view of GenericIntStruct.
+func (p *GenericIntStruct[T]) View() GenericIntStructView[T] {
+	return GenericIntStructView[T]{ж: p}
+}
+
+// GenericIntStructView[T] provides a read-only view over GenericIntStruct[T].
+//
+// Its methods should only be called if `Valid()` returns true.
+type GenericIntStructView[T constraints.Integer] struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *GenericIntStruct[T]
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v GenericIntStructView[T]) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v GenericIntStructView[T]) AsStruct() *GenericIntStruct[T] {
+	if v.ж == nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v GenericIntStructView[T]) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *GenericIntStructView[T]) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x GenericIntStruct[T]
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v GenericIntStructView[T]) Value() T { return v.ж.Value }
+func (v GenericIntStructView[T]) Pointer() *T {
+	if v.ж.Pointer == nil {
+		return nil
+	}
+	x := *v.ж.Pointer
+	return &x
+}
+
+func (v GenericIntStructView[T]) Slice() views.Slice[T] { return views.SliceOf(v.ж.Slice) }
+
+func (v GenericIntStructView[T]) Map() views.Map[string, T]  { return views.MapOf(v.ж.Map) }
+func (v GenericIntStructView[T]) PtrSlice() *T               { panic("unsupported") }
+func (v GenericIntStructView[T]) PtrKeyMap() map[*T]string   { panic("unsupported") }
+func (v GenericIntStructView[T]) PtrValueMap() map[string]*T { panic("unsupported") }
+func (v GenericIntStructView[T]) SliceMap() map[string][]T   { panic("unsupported") }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericIntStructViewNeedsRegeneration[T constraints.Integer](GenericIntStruct[T]) {
+	_GenericIntStructViewNeedsRegeneration(struct {
+		Value       T
+		Pointer     *T
+		Slice       []T
+		Map         map[string]T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}
+
+// View returns a readonly view of GenericNoPtrsStruct.
+func (p *GenericNoPtrsStruct[T]) View() GenericNoPtrsStructView[T] {
+	return GenericNoPtrsStructView[T]{ж: p}
+}
+
+// GenericNoPtrsStructView[T] provides a read-only view over GenericNoPtrsStruct[T].
+//
+// Its methods should only be called if `Valid()` returns true.
+type GenericNoPtrsStructView[T StructWithoutPtrs | netip.Prefix | BasicType] struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *GenericNoPtrsStruct[T]
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v GenericNoPtrsStructView[T]) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v GenericNoPtrsStructView[T]) AsStruct() *GenericNoPtrsStruct[T] {
+	if v.ж == nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v GenericNoPtrsStructView[T]) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *GenericNoPtrsStructView[T]) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x GenericNoPtrsStruct[T]
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v GenericNoPtrsStructView[T]) Value() T { return v.ж.Value }
+func (v GenericNoPtrsStructView[T]) Pointer() *T {
+	if v.ж.Pointer == nil {
+		return nil
+	}
+	x := *v.ж.Pointer
+	return &x
+}
+
+func (v GenericNoPtrsStructView[T]) Slice() views.Slice[T] { return views.SliceOf(v.ж.Slice) }
+
+func (v GenericNoPtrsStructView[T]) Map() views.Map[string, T]  { return views.MapOf(v.ж.Map) }
+func (v GenericNoPtrsStructView[T]) PtrSlice() *T               { panic("unsupported") }
+func (v GenericNoPtrsStructView[T]) PtrKeyMap() map[*T]string   { panic("unsupported") }
+func (v GenericNoPtrsStructView[T]) PtrValueMap() map[string]*T { panic("unsupported") }
+func (v GenericNoPtrsStructView[T]) SliceMap() map[string][]T   { panic("unsupported") }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericNoPtrsStructViewNeedsRegeneration[T StructWithoutPtrs | netip.Prefix | BasicType](GenericNoPtrsStruct[T]) {
+	_GenericNoPtrsStructViewNeedsRegeneration(struct {
+		Value       T
+		Pointer     *T
+		Slice       []T
+		Map         map[string]T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}
+
+// View returns a readonly view of GenericCloneableStruct.
+func (p *GenericCloneableStruct[T, V]) View() GenericCloneableStructView[T, V] {
+	return GenericCloneableStructView[T, V]{ж: p}
+}
+
+// GenericCloneableStructView[T, V] provides a read-only view over GenericCloneableStruct[T, V].
+//
+// Its methods should only be called if `Valid()` returns true.
+type GenericCloneableStructView[T views.ViewCloner[T, V], V views.StructView[T]] struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *GenericCloneableStruct[T, V]
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v GenericCloneableStructView[T, V]) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v GenericCloneableStructView[T, V]) AsStruct() *GenericCloneableStruct[T, V] {
+	if v.ж == nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v GenericCloneableStructView[T, V]) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *GenericCloneableStructView[T, V]) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x GenericCloneableStruct[T, V]
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v GenericCloneableStructView[T, V]) Value() V { return v.ж.Value.View() }
+func (v GenericCloneableStructView[T, V]) Slice() views.SliceView[T, V] {
+	return views.SliceOfViews[T, V](v.ж.Slice)
+}
+
+func (v GenericCloneableStructView[T, V]) Map() views.MapFn[string, T, V] {
+	return views.MapFnOf(v.ж.Map, func(t T) V {
+		return t.View()
+	})
+}
+func (v GenericCloneableStructView[T, V]) Pointer() map[string]T      { panic("unsupported") }
+func (v GenericCloneableStructView[T, V]) PtrSlice() *T               { panic("unsupported") }
+func (v GenericCloneableStructView[T, V]) PtrKeyMap() map[*T]string   { panic("unsupported") }
+func (v GenericCloneableStructView[T, V]) PtrValueMap() map[string]*T { panic("unsupported") }
+func (v GenericCloneableStructView[T, V]) SliceMap() map[string][]T   { panic("unsupported") }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+func _GenericCloneableStructViewNeedsRegeneration[T views.ViewCloner[T, V], V views.StructView[T]](GenericCloneableStruct[T, V]) {
+	_GenericCloneableStructViewNeedsRegeneration(struct {
+		Value       T
+		Slice       []T
+		Map         map[string]T
+		Pointer     *T
+		PtrSlice    []*T
+		PtrKeyMap   map[*T]string `json:"-"`
+		PtrValueMap map[string]*T
+		SliceMap    map[string][]T
+	}{})
+}
+
+// View returns a readonly view of StructWithContainers.
+func (p *StructWithContainers) View() StructWithContainersView {
+	return StructWithContainersView{ж: p}
+}
+
+// StructWithContainersView provides a read-only view over StructWithContainers.
+//
+// Its methods should only be called if `Valid()` returns true.
+type StructWithContainersView struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *StructWithContainers
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v StructWithContainersView) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v StructWithContainersView) AsStruct() *StructWithContainers {
+	if v.ж == nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v StructWithContainersView) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *StructWithContainersView) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x StructWithContainers
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v StructWithContainersView) IntContainer() Container[int] { return v.ж.IntContainer }
+func (v StructWithContainersView) CloneableContainer() ContainerView[*StructWithPtrs, StructWithPtrsView] {
+	return ContainerViewOf(&v.ж.CloneableContainer)
+}
+func (v StructWithContainersView) BasicGenericContainer() Container[GenericBasicStruct[int]] {
+	return v.ж.BasicGenericContainer
+}
+func (v StructWithContainersView) CloneableGenericContainer() ContainerView[*GenericNoPtrsStruct[int], GenericNoPtrsStructView[int]] {
+	return ContainerViewOf(&v.ж.CloneableGenericContainer)
+}
+func (v StructWithContainersView) CloneableMap() MapContainerView[int, *StructWithPtrs, StructWithPtrsView] {
+	return MapContainerViewOf(&v.ж.CloneableMap)
+}
+func (v StructWithContainersView) CloneableGenericMap() MapContainerView[int, *GenericNoPtrsStruct[int], GenericNoPtrsStructView[int]] {
+	return MapContainerViewOf(&v.ж.CloneableGenericMap)
+}
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _StructWithContainersViewNeedsRegeneration = StructWithContainers(struct {
+	IntContainer              Container[int]
+	CloneableContainer        Container[*StructWithPtrs]
+	BasicGenericContainer     Container[GenericBasicStruct[int]]
+	CloneableGenericContainer Container[*GenericNoPtrsStruct[int]]
+	CloneableMap              MapContainer[int, *StructWithPtrs]
+	CloneableGenericMap       MapContainer[int, *GenericNoPtrsStruct[int]]
+}{})

cmd/viewer/viewer.go

@@ -13,50 +13,52 @@ import (
 	"html/template"
 	"log"
 	"os"
+	"slices"
 	"strings"
 
 	"tailscale.com/util/codegen"
+	"tailscale.com/util/must"
 )
 
 const viewTemplateStr = `{{define "common"}}
 // View returns a readonly view of {{.StructName}}.
-func (p *{{.StructName}}) View() {{.ViewName}} {
-	return {{.ViewName}}{ж: p}
+func (p *{{.StructName}}{{.TypeParamNames}}) View() {{.ViewName}}{{.TypeParamNames}} {
+	return {{.ViewName}}{{.TypeParamNames}}{ж: p}
 }
 
-// {{.ViewName}} provides a read-only view over {{.StructName}}.
+// {{.ViewName}}{{.TypeParamNames}} provides a read-only view over {{.StructName}}{{.TypeParamNames}}.
 //
 // Its methods should only be called if ` + "`Valid()`" + ` returns true.
-type {{.ViewName}} struct {
+type {{.ViewName}}{{.TypeParams}} struct {
 	// ж is the underlying mutable value, named with a hard-to-type
 	// character that looks pointy like a pointer.
 	// It is named distinctively to make you think of how dangerous it is to escape
 	// to callers. You must not let callers be able to mutate it.
-	ж *{{.StructName}}
+	ж *{{.StructName}}{{.TypeParamNames}}
 }
 
 // Valid reports whether underlying value is non-nil.
-func (v {{.ViewName}}) Valid() bool { return v.ж != nil }
+func (v {{.ViewName}}{{.TypeParamNames}}) Valid() bool { return v.ж != nil }
 
 // AsStruct returns a clone of the underlying value which aliases no memory with
 // the original.
-func (v {{.ViewName}}) AsStruct() *{{.StructName}}{ 
+func (v {{.ViewName}}{{.TypeParamNames}}) AsStruct() *{{.StructName}}{{.TypeParamNames}}{ 
 	if v.ж == nil {
 		return nil
 	}
 	return v.ж.Clone()
 }
 
-func (v {{.ViewName}}) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+func (v {{.ViewName}}{{.TypeParamNames}}) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
 
-func (v *{{.ViewName}}) UnmarshalJSON(b []byte) error {
+func (v *{{.ViewName}}{{.TypeParamNames}}) UnmarshalJSON(b []byte) error {
 	if v.ж != nil {
 		return errors.New("already initialized")
 	}
 	if len(b) == 0 {
 		return nil
 	}
-	var x {{.StructName}}
+	var x {{.StructName}}{{.TypeParamNames}}
 	if err := json.Unmarshal(b, &x); err != nil {
 		return err
 	}
@@ -65,17 +67,19 @@ func (v *{{.ViewName}}) UnmarshalJSON(b []byte) error {
 }
 
 {{end}}
-{{define "valueField"}}func (v {{.ViewName}}) {{.FieldName}}() {{.FieldType}} { return v.ж.{{.FieldName}} }
+{{define "valueField"}}func (v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() {{.FieldType}} { return v.ж.{{.FieldName}} }
 {{end}}
-{{define "byteSliceField"}}func (v {{.ViewName}}) {{.FieldName}}() views.ByteSlice[{{.FieldType}}] { return views.ByteSliceOf(v.ж.{{.FieldName}}) }
+{{define "byteSliceField"}}func (v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() views.ByteSlice[{{.FieldType}}] { return views.ByteSliceOf(v.ж.{{.FieldName}}) }
 {{end}}
-{{define "sliceField"}}func (v {{.ViewName}}) {{.FieldName}}() views.Slice[{{.FieldType}}] { return views.SliceOf(v.ж.{{.FieldName}}) }
+{{define "sliceField"}}func (v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() views.Slice[{{.FieldType}}] { return views.SliceOf(v.ж.{{.FieldName}}) }
 {{end}}
-{{define "viewSliceField"}}func (v {{.ViewName}}) {{.FieldName}}() views.SliceView[{{.FieldType}},{{.FieldViewName}}] { return views.SliceOfViews[{{.FieldType}},{{.FieldViewName}}](v.ж.{{.FieldName}}) }
+{{define "viewSliceField"}}func (v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() views.SliceView[{{.FieldType}},{{.FieldViewName}}] { return views.SliceOfViews[{{.FieldType}},{{.FieldViewName}}](v.ж.{{.FieldName}}) }
 {{end}}
-{{define "viewField"}}func (v {{.ViewName}}) {{.FieldName}}() {{.FieldType}}View { return v.ж.{{.FieldName}}.View() }
+{{define "viewField"}}func (v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() {{.FieldViewName}} { return v.ж.{{.FieldName}}.View() }
 {{end}}
-{{define "valuePointerField"}}func (v {{.ViewName}}) {{.FieldName}}() {{.FieldType}} {
+{{define "makeViewField"}}func (v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() {{.FieldViewName}} { return {{.MakeViewFnName}}(&v.ж.{{.FieldName}}) }
+{{end}}
+{{define "valuePointerField"}}func (v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() {{.FieldType}} {
 	if v.ж.{{.FieldName}} == nil {
 		return nil
 	}
@@ -85,21 +89,21 @@ func (v *{{.ViewName}}) UnmarshalJSON(b []byte) error {
 
 {{end}}
 {{define "mapField"}}
-func(v {{.ViewName}}) {{.FieldName}}() views.Map[{{.MapKeyType}},{{.MapValueType}}] { return views.MapOf(v.ж.{{.FieldName}})}
+func(v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() views.Map[{{.MapKeyType}},{{.MapValueType}}] { return views.MapOf(v.ж.{{.FieldName}})}
 {{end}}
 {{define "mapFnField"}}
-func(v {{.ViewName}}) {{.FieldName}}() views.MapFn[{{.MapKeyType}},{{.MapValueType}},{{.MapValueView}}] { return views.MapFnOf(v.ж.{{.FieldName}}, func (t {{.MapValueType}}) {{.MapValueView}} {
+func(v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() views.MapFn[{{.MapKeyType}},{{.MapValueType}},{{.MapValueView}}] { return views.MapFnOf(v.ж.{{.FieldName}}, func (t {{.MapValueType}}) {{.MapValueView}} {
 	return {{.MapFn}}
 })}
 {{end}}
 {{define "mapSliceField"}}
-func(v {{.ViewName}}) {{.FieldName}}() views.MapSlice[{{.MapKeyType}},{{.MapValueType}}] { return views.MapSliceOf(v.ж.{{.FieldName}}) }
+func(v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() views.MapSlice[{{.MapKeyType}},{{.MapValueType}}] { return views.MapSliceOf(v.ж.{{.FieldName}}) }
 {{end}}
-{{define "unsupportedField"}}func(v {{.ViewName}}) {{.FieldName}}() {{.FieldType}} {panic("unsupported")}
+{{define "unsupportedField"}}func(v {{.ViewName}}{{.TypeParamNames}}) {{.FieldName}}() {{.FieldType}} {panic("unsupported")}
 {{end}}
-{{define "stringFunc"}}func(v {{.ViewName}}) String() string { return v.ж.String() }
+{{define "stringFunc"}}func(v {{.ViewName}}{{.TypeParamNames}}) String() string { return v.ж.String() }
 {{end}}
-{{define "equalFunc"}}func(v {{.ViewName}}) Equal(v2 {{.ViewName}}) bool { return v.ж.Equal(v2.ж) }
+{{define "equalFunc"}}func(v {{.ViewName}}{{.TypeParamNames}}) Equal(v2 {{.ViewName}}{{.TypeParamNames}}) bool { return v.ж.Equal(v2.ж) }
 {{end}}
 `
 
@@ -131,8 +135,11 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 	it.Import("errors")
 
 	args := struct {
-		StructName    string
-		ViewName      string
+		StructName     string
+		ViewName       string
+		TypeParams     string // e.g. [T constraints.Integer]
+		TypeParamNames string // e.g. [T]
+
 		FieldName     string
 		FieldType     string
 		FieldViewName string
@@ -141,11 +148,17 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 		MapValueType string
 		MapValueView string
 		MapFn        string
+
+		// MakeViewFnName is the name of the function that accepts a value and returns a readonly view of it.
+		MakeViewFnName string
 	}{
 		StructName: typ.Obj().Name(),
-		ViewName:   typ.Obj().Name() + "View",
+		ViewName:   typ.Origin().Obj().Name() + "View",
 	}
 
+	typeParams := typ.Origin().TypeParams()
+	args.TypeParams, args.TypeParamNames = codegen.FormatTypeParams(typeParams, it)
+
 	writeTemplate := func(name string) {
 		if err := viewTemplate.ExecuteTemplate(buf, name, args); err != nil {
 			log.Fatal(err)
@@ -182,19 +195,35 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 				it.Import("tailscale.com/types/views")
 				shallow, deep, base := requiresCloning(elem)
 				if deep {
-					if _, isPtr := elem.(*types.Pointer); isPtr {
-						args.FieldViewName = it.QualifiedName(base) + "View"
-						writeTemplate("viewSliceField")
-					} else {
-						writeTemplate("unsupportedField")
+					switch elem.Underlying().(type) {
+					case *types.Pointer:
+						if _, isIface := base.Underlying().(*types.Interface); !isIface {
+							args.FieldViewName = appendNameSuffix(it.QualifiedName(base), "View")
+							writeTemplate("viewSliceField")
+						} else {
+							writeTemplate("unsupportedField")
+						}
+						continue
+					case *types.Interface:
+						if viewType := viewTypeForValueType(elem); viewType != nil {
+							args.FieldViewName = it.QualifiedName(viewType)
+							writeTemplate("viewSliceField")
+							continue
+						}
 					}
+					writeTemplate("unsupportedField")
 					continue
 				} else if shallow {
-					if _, isBasic := base.(*types.Basic); isBasic {
+					switch base.Underlying().(type) {
+					case *types.Basic, *types.Interface:
 						writeTemplate("unsupportedField")
-					} else {
-						args.FieldViewName = it.QualifiedName(base) + "View"
-						writeTemplate("viewSliceField")
+					default:
+						if _, isIface := base.Underlying().(*types.Interface); !isIface {
+							args.FieldViewName = appendNameSuffix(it.QualifiedName(base), "View")
+							writeTemplate("viewSliceField")
+						} else {
+							writeTemplate("unsupportedField")
+						}
 					}
 					continue
 				}
@@ -205,7 +234,18 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 			strucT := underlying
 			args.FieldType = it.QualifiedName(fieldType)
 			if codegen.ContainsPointers(strucT) {
-				writeTemplate("viewField")
+				if viewType := viewTypeForValueType(fieldType); viewType != nil {
+					args.FieldViewName = it.QualifiedName(viewType)
+					writeTemplate("viewField")
+					continue
+				}
+				if viewType, makeViewFn := viewTypeForContainerType(fieldType); viewType != nil {
+					args.FieldViewName = it.QualifiedName(viewType)
+					args.MakeViewFnName = it.PackagePrefix(makeViewFn.Pkg()) + makeViewFn.Name()
+					writeTemplate("makeViewField")
+					continue
+				}
+				writeTemplate("unsupportedField")
 				continue
 			}
 			writeTemplate("valueField")
@@ -229,7 +269,7 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 					args.MapFn = "t.View()"
 					template = "mapFnField"
 					args.MapValueType = it.QualifiedName(mElem)
-					args.MapValueView = args.MapValueType + "View"
+					args.MapValueView = appendNameSuffix(args.MapValueType, "View")
 				} else {
 					template = "mapField"
 					args.MapValueType = it.QualifiedName(mElem)
@@ -249,15 +289,20 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 				case *types.Pointer:
 					ptr := x
 					pElem := ptr.Elem()
-					switch pElem.(type) {
-					case *types.Struct, *types.Named:
-						ptrType := it.QualifiedName(ptr)
-						viewType := it.QualifiedName(pElem) + "View"
-						args.MapFn = fmt.Sprintf("views.SliceOfViews[%v,%v](t)", ptrType, viewType)
-						args.MapValueView = fmt.Sprintf("views.SliceView[%v,%v]", ptrType, viewType)
-						args.MapValueType = "[]" + ptrType
-						template = "mapFnField"
-					default:
+					template = "unsupportedField"
+					if _, isIface := pElem.Underlying().(*types.Interface); !isIface {
+						switch pElem.(type) {
+						case *types.Struct, *types.Named:
+							ptrType := it.QualifiedName(ptr)
+							viewType := appendNameSuffix(it.QualifiedName(pElem), "View")
+							args.MapFn = fmt.Sprintf("views.SliceOfViews[%v,%v](t)", ptrType, viewType)
+							args.MapValueView = fmt.Sprintf("views.SliceView[%v,%v]", ptrType, viewType)
+							args.MapValueType = "[]" + ptrType
+							template = "mapFnField"
+						default:
+							template = "unsupportedField"
+						}
+					} else {
 						template = "unsupportedField"
 					}
 				default:
@@ -266,13 +311,29 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 			case *types.Pointer:
 				ptr := u
 				pElem := ptr.Elem()
-				switch pElem.(type) {
-				case *types.Struct, *types.Named:
-					args.MapValueType = it.QualifiedName(ptr)
-					args.MapValueView = it.QualifiedName(pElem) + "View"
+				if _, isIface := pElem.Underlying().(*types.Interface); !isIface {
+					switch pElem.(type) {
+					case *types.Struct, *types.Named:
+						args.MapValueType = it.QualifiedName(ptr)
+						args.MapValueView = appendNameSuffix(it.QualifiedName(pElem), "View")
+						args.MapFn = "t.View()"
+						template = "mapFnField"
+					default:
+						template = "unsupportedField"
+					}
+				} else {
+					template = "unsupportedField"
+				}
+			case *types.Interface, *types.TypeParam:
+				if viewType := viewTypeForValueType(u); viewType != nil {
+					args.MapValueType = it.QualifiedName(u)
+					args.MapValueView = it.QualifiedName(viewType)
 					args.MapFn = "t.View()"
 					template = "mapFnField"
-				default:
+				} else if !codegen.ContainsPointers(u) {
+					args.MapValueType = it.QualifiedName(mElem)
+					template = "mapField"
+				} else {
 					template = "unsupportedField"
 				}
 			default:
@@ -283,14 +344,28 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 		case *types.Pointer:
 			ptr := underlying
 			_, deep, base := requiresCloning(ptr)
+
 			if deep {
-				args.FieldType = it.QualifiedName(base)
-				writeTemplate("viewField")
+				if _, isIface := base.Underlying().(*types.Interface); !isIface {
+					args.FieldType = it.QualifiedName(base)
+					args.FieldViewName = appendNameSuffix(args.FieldType, "View")
+					writeTemplate("viewField")
+				} else {
+					writeTemplate("unsupportedField")
+				}
 			} else {
 				args.FieldType = it.QualifiedName(ptr)
 				writeTemplate("valuePointerField")
 			}
 			continue
+		case *types.Interface:
+			// If fieldType is an interface with a "View() {ViewType}" method, it can be used to clone the field.
+			// This includes scenarios where fieldType is a constrained type parameter.
+			if viewType := viewTypeForValueType(underlying); viewType != nil {
+				args.FieldViewName = it.QualifiedName(viewType)
+				writeTemplate("viewField")
+				continue
+			}
 		}
 		writeTemplate("unsupportedField")
 	}
@@ -318,7 +393,132 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 		}
 	}
 	fmt.Fprintf(buf, "\n")
-	buf.Write(codegen.AssertStructUnchanged(t, args.StructName, "View", it))
+	buf.Write(codegen.AssertStructUnchanged(t, args.StructName, typeParams, "View", it))
+}
+
+func appendNameSuffix(name, suffix string) string {
+	if idx := strings.IndexRune(name, '['); idx != -1 {
+		// Insert suffix after the type name, but before type parameters.
+		return name[:idx] + suffix + name[idx:]
+	}
+	return name + suffix
+}
+
+func viewTypeForValueType(typ types.Type) types.Type {
+	if ptr, ok := typ.(*types.Pointer); ok {
+		return viewTypeForValueType(ptr.Elem())
+	}
+	viewMethod := codegen.LookupMethod(typ, "View")
+	if viewMethod == nil {
+		return nil
+	}
+	sig, ok := viewMethod.Type().(*types.Signature)
+	if !ok || sig.Results().Len() != 1 {
+		return nil
+	}
+	return sig.Results().At(0).Type()
+}
+
+func viewTypeForContainerType(typ types.Type) (*types.Named, *types.Func) {
+	// The container type should be an instantiated generic type,
+	// with its first type parameter specifying the element type.
+	containerType, ok := typ.(*types.Named)
+	if !ok || containerType.TypeArgs().Len() == 0 {
+		return nil, nil
+	}
+
+	// Look up the view type for the container type.
+	// It must include an additional type parameter specifying the element's view type.
+	// For example, Container[T] => ContainerView[T, V].
+	containerViewTypeName := containerType.Obj().Name() + "View"
+	containerViewTypeObj, ok := containerType.Obj().Pkg().Scope().Lookup(containerViewTypeName).(*types.TypeName)
+	if !ok {
+		return nil, nil
+	}
+	containerViewGenericType, ok := containerViewTypeObj.Type().(*types.Named)
+	if !ok || containerViewGenericType.TypeParams().Len() != containerType.TypeArgs().Len()+1 {
+		return nil, nil
+	}
+
+	// Create a list of type arguments for instantiating the container view type.
+	// Include all type arguments specified for the container type...
+	containerViewTypeArgs := make([]types.Type, containerViewGenericType.TypeParams().Len())
+	for i := range containerType.TypeArgs().Len() {
+		containerViewTypeArgs[i] = containerType.TypeArgs().At(i)
+	}
+	// ...and add the element view type.
+	// For that, we need to first determine the named elem type...
+	elemType, ok := baseType(containerType.TypeArgs().At(containerType.TypeArgs().Len() - 1)).(*types.Named)
+	if !ok {
+		return nil, nil
+	}
+	// ...then infer the view type from it.
+	var elemViewType *types.Named
+	elemTypeName := elemType.Obj().Name()
+	elemViewTypeBaseName := elemType.Obj().Name() + "View"
+	if elemViewTypeName, ok := elemType.Obj().Pkg().Scope().Lookup(elemViewTypeBaseName).(*types.TypeName); ok {
+		// The elem's view type is already defined in the same package as the elem type.
+		elemViewType = elemViewTypeName.Type().(*types.Named)
+	} else if slices.Contains(typeNames, elemTypeName) {
+		// The elem's view type has not been generated yet, but we can define
+		// and use a blank type with the expected view type name.
+		elemViewTypeName = types.NewTypeName(0, elemType.Obj().Pkg(), elemViewTypeBaseName, nil)
+		elemViewType = types.NewNamed(elemViewTypeName, types.NewStruct(nil, nil), nil)
+		if elemTypeParams := elemType.TypeParams(); elemTypeParams != nil {
+			elemViewType.SetTypeParams(collectTypeParams(elemTypeParams))
+		}
+	} else {
+		// The elem view type does not exist and won't be generated.
+		return nil, nil
+	}
+	// If elemType is an instantiated generic type, instantiate the elemViewType as well.
+	if elemTypeArgs := elemType.TypeArgs(); elemTypeArgs != nil {
+		elemViewType = must.Get(types.Instantiate(nil, elemViewType, collectTypes(elemTypeArgs), false)).(*types.Named)
+	}
+	// And finally set the elemViewType as the last type argument.
+	containerViewTypeArgs[len(containerViewTypeArgs)-1] = elemViewType
+
+	// Instantiate the container view type with the specified type arguments.
+	containerViewType := must.Get(types.Instantiate(nil, containerViewGenericType, containerViewTypeArgs, false))
+	// Look up a function to create a view of a container.
+	// It should be in the same package as the container type, named {ViewType}Of,
+	// and have a signature like {ViewType}Of(c *Container[T]) ContainerView[T, V].
+	makeContainerView, ok := containerType.Obj().Pkg().Scope().Lookup(containerViewTypeName + "Of").(*types.Func)
+	if !ok {
+		return nil, nil
+	}
+	return containerViewType.(*types.Named), makeContainerView
+}
+
+func baseType(typ types.Type) types.Type {
+	if ptr, ok := typ.(*types.Pointer); ok {
+		return ptr.Elem()
+	}
+	return typ
+}
+
+func collectTypes(list *types.TypeList) []types.Type {
+	// TODO(nickkhyl): use slices.Collect in Go 1.23?
+	if list.Len() == 0 {
+		return nil
+	}
+	res := make([]types.Type, list.Len())
+	for i := range res {
+		res[i] = list.At(i)
+	}
+	return res
+}
+
+func collectTypeParams(list *types.TypeParamList) []*types.TypeParam {
+	if list.Len() == 0 {
+		return nil
+	}
+	res := make([]*types.TypeParam, list.Len())
+	for i := range res {
+		p := list.At(i)
+		res[i] = types.NewTypeParam(p.Obj(), p.Constraint())
+	}
+	return res
 }
 
 var (
@@ -327,6 +527,8 @@ var (
 	flagCloneFunc = flag.Bool("clonefunc", false, "add a top-level Clone func")
 
 	flagCloneOnlyTypes = flag.String("clone-only-type", "", "comma-separated list of types (a subset of --type) that should only generate a go:generate clone line and not actual views")
+
+	typeNames []string
 )
 
 func main() {
@@ -337,7 +539,7 @@ func main() {
 		flag.Usage()
 		os.Exit(2)
 	}
-	typeNames := strings.Split(*flagTypes, ",")
+	typeNames = strings.Split(*flagTypes, ",")
 
 	var flagArgs []string
 	flagArgs = append(flagArgs, fmt.Sprintf("-clonefunc=%v", *flagCloneFunc))
@@ -381,7 +583,11 @@ func main() {
 		}
 		genView(buf, it, typ, pkg.Types)
 	}
-	out := pkg.Name + "_view.go"
+	out := pkg.Name + "_view"
+	if *flagBuildTags == "test" {
+		out += "_test"
+	}
+	out += ".go"
 	if err := codegen.WritePackageFile("tailscale/cmd/viewer", pkg, out, it, buf); err != nil {
 		log.Fatal(err)
 	}

cmd/vnet/run-krazy.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+echo "Type 'C-a c' to enter monitor; q to quit."
+
+set -eux
+qemu-system-x86_64 -M microvm,isa-serial=off \
+    -m 1G \
+    -nodefaults -no-user-config -nographic \
+    -kernel $HOME/src/github.com/tailscale/gokrazy-kernel/vmlinuz \
+    -append "console=hvc0 root=PARTUUID=60c24cc1-f3f9-427a-8199-76baa2d60001/PARTNROFF=1 ro init=/gokrazy/init panic=10 oops=panic pci=off nousb tsc=unstable clocksource=hpet tailscale-tta=1 tailscaled.env=TS_DEBUG_RAW_DISCO=1" \
+    -drive id=blk0,file=$HOME/src/tailscale.com/gokrazy/natlabapp.img,format=raw \
+    -device virtio-blk-device,drive=blk0 \
+    -device virtio-rng-device \
+    -netdev stream,id=net0,addr.type=unix,addr.path=/tmp/qemu.sock \
+    -device virtio-serial-device \
+    -device virtio-net-device,netdev=net0,mac=52:cc:cc:cc:cc:01 \
+    -chardev stdio,id=virtiocon0,mux=on \
+    -device virtconsole,chardev=virtiocon0 \
+    -mon chardev=virtiocon0,mode=readline \
+    -audio none
+

cmd/vnet/vnet-main.go

@@ -0,0 +1,118 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// The vnet binary runs a virtual network stack in userspace for qemu instances
+// to connect to and simulate various network conditions.
+package main
+
+import (
+	"context"
+	"flag"
+	"log"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"os"
+	"time"
+
+	"tailscale.com/tstest/natlab/vnet"
+	"tailscale.com/types/logger"
+	"tailscale.com/util/must"
+)
+
+var (
+	listen  = flag.String("listen", "/tmp/qemu.sock", "path to listen on")
+	nat     = flag.String("nat", "easy", "type of NAT to use")
+	nat2    = flag.String("nat2", "hard", "type of NAT to use for second network")
+	portmap = flag.Bool("portmap", false, "enable portmapping")
+	dgram   = flag.Bool("dgram", false, "enable datagram mode; for use with macOS Hypervisor.Framework and VZFileHandleNetworkDeviceAttachment")
+)
+
+func main() {
+	flag.Parse()
+
+	if _, err := os.Stat(*listen); err == nil {
+		os.Remove(*listen)
+	}
+
+	var srv net.Listener
+	var err error
+	var conn *net.UnixConn
+	if *dgram {
+		addr, err := net.ResolveUnixAddr("unixgram", *listen)
+		if err != nil {
+			log.Fatalf("ResolveUnixAddr: %v", err)
+		}
+		conn, err = net.ListenUnixgram("unixgram", addr)
+		if err != nil {
+			log.Fatalf("ListenUnixgram: %v", err)
+		}
+		defer conn.Close()
+	} else {
+		srv, err = net.Listen("unix", *listen)
+	}
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var c vnet.Config
+	node1 := c.AddNode(c.AddNetwork("2.1.1.1", "192.168.1.1/24", vnet.NAT(*nat)))
+	c.AddNode(c.AddNetwork("2.2.2.2", "10.2.0.1/16", vnet.NAT(*nat2)))
+	if *portmap {
+		node1.Network().AddService(vnet.NATPMP)
+	}
+
+	s, err := vnet.New(&c)
+	if err != nil {
+		log.Fatalf("newServer: %v", err)
+	}
+
+	if err := s.PopulateDERPMapIPs(); err != nil {
+		log.Printf("warning: ignoring failure to populate DERP map: %v", err)
+	}
+
+	s.WriteStartingBanner(os.Stdout)
+	nc := s.NodeAgentClient(node1)
+	go func() {
+		rp := httputil.NewSingleHostReverseProxy(must.Get(url.Parse("http://gokrazy")))
+		d := rp.Director
+		rp.Director = func(r *http.Request) {
+			d(r)
+			r.Header.Set("X-TTA-GoKrazy", "1")
+		}
+		rp.Transport = nc.HTTPClient.Transport
+		http.ListenAndServe(":8080", rp)
+	}()
+	go func() {
+		getStatus := func() {
+			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+			defer cancel()
+			st, err := nc.Status(ctx)
+			if err != nil {
+				log.Printf("NodeStatus: %v", err)
+				return
+			}
+			log.Printf("NodeStatus: %v", logger.AsJSON(st))
+		}
+		for {
+			time.Sleep(5 * time.Second)
+			//continue
+			getStatus()
+		}
+	}()
+
+	if conn != nil {
+		s.ServeUnixConn(conn, vnet.ProtocolUnixDGRAM)
+		return
+	}
+
+	for {
+		c, err := srv.Accept()
+		if err != nil {
+			log.Printf("Accept: %v", err)
+			continue
+		}
+		go s.ServeUnixConn(c.(*net.UnixConn), vnet.ProtocolQEMU)
+	}
+}

cmd/xdpderper/xdpderper.go

@@ -1,6 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// Command xdpderper runs the XDP STUN server.
 package main
 
 import (
@@ -15,11 +16,12 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"tailscale.com/derp/xdp"
+	"tailscale.com/net/netutil"
 	"tailscale.com/tsweb"
 )
 
 var (
-	flagDevice  = flag.String("device", "", "target device name")
+	flagDevice  = flag.String("device", "", "target device name (default: autodetect)")
 	flagPort    = flag.Int("dst-port", 0, "destination UDP port to serve")
 	flagVerbose = flag.Bool("verbose", false, "verbose output including verifier errors")
 	flagMode    = flag.String("mode", "xdp", "XDP mode; valid modes: [xdp, xdpgeneric, xdpdrv, xdpoffload]")
@@ -41,8 +43,18 @@ func main() {
 	default:
 		log.Fatal("invalid mode")
 	}
+	deviceName := *flagDevice
+	if deviceName == "" {
+		var err error
+		deviceName, _, err = netutil.DefaultInterfacePortable()
+		if err != nil || deviceName == "" {
+			log.Fatalf("failed to detect default route interface: %v", err)
+		}
+	}
+	log.Printf("binding to device: %s", deviceName)
+
 	server, err := xdp.NewSTUNServer(&xdp.STUNServerConfig{
-		DeviceName:      *flagDevice,
+		DeviceName:      deviceName,
 		DstPort:         *flagPort,
 		AttachFlags:     attachFlags,
 		FullVerifierErr: *flagVerbose,

control/controlclient/direct.go

@@ -7,8 +7,6 @@ import (
 	"bufio"
 	"bytes"
 	"context"
-	"crypto/ed25519"
-	"encoding/base64"
 	"encoding/binary"
 	"encoding/json"
 	"errors"
@@ -335,6 +333,9 @@ func (c *Direct) Close() error {
 		}
 	}
 	c.noiseClient = nil
+	if tr, ok := c.httpc.Transport.(*http.Transport); ok {
+		tr.CloseIdleConnections()
+	}
 	return nil
 }
 
@@ -491,7 +492,7 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 	tryingNewKey := c.tryingNewKey
 	serverKey := c.serverLegacyKey
 	serverNoiseKey := c.serverNoiseKey
-	authKey, isWrapped, wrappedSig, wrappedKey := decodeWrappedAuthkey(c.authKey, c.logf)
+	authKey, isWrapped, wrappedSig, wrappedKey := tka.DecodeWrappedAuthkey(c.authKey, c.logf)
 	hi := c.hostInfoLocked()
 	backendLogID := hi.BackendLogID
 	expired := !c.expiry.IsZero() && c.expiry.Before(c.clock.Now())
@@ -588,18 +589,10 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 		// We were given a wrapped pre-auth key, which means that in addition
 		// to being a regular pre-auth key there was a suffix with information to
 		// generate a tailnet-lock signature.
-		nk, err := tryingNewKey.Public().MarshalBinary()
+		nodeKeySignature, err = tka.SignByCredential(wrappedKey, wrappedSig, tryingNewKey.Public())
 		if err != nil {
-			return false, "", nil, fmt.Errorf("marshalling node-key: %w", err)
+			return false, "", nil, err
 		}
-		sig := &tka.NodeKeySignature{
-			SigKind: tka.SigRotation,
-			Pubkey:  nk,
-			Nested:  wrappedSig,
-		}
-		sigHash := sig.SigHash()
-		sig.Signature = ed25519.Sign(wrappedKey, sigHash[:])
-		nodeKeySignature = sig.Serialize()
 	}
 
 	if backendLogID == "" {
@@ -1644,43 +1637,6 @@ func (c *Direct) ReportHealthChange(w *health.Warnable, us *health.UnhealthyStat
 	res.Body.Close()
 }
 
-// decodeWrappedAuthkey separates wrapping information from an authkey, if any.
-// In all cases the authkey is returned, sans wrapping information if any.
-//
-// If the authkey is wrapped, isWrapped returns true, along with the wrapping signature
-// and private key.
-func decodeWrappedAuthkey(key string, logf logger.Logf) (authKey string, isWrapped bool, sig *tka.NodeKeySignature, priv ed25519.PrivateKey) {
-	authKey, suffix, found := strings.Cut(key, "--TL")
-	if !found {
-		return key, false, nil, nil
-	}
-	sigBytes, privBytes, found := strings.Cut(suffix, "-")
-	if !found {
-		logf("decoding wrapped auth-key: did not find delimiter")
-		return key, false, nil, nil
-	}
-
-	rawSig, err := base64.RawStdEncoding.DecodeString(sigBytes)
-	if err != nil {
-		logf("decoding wrapped auth-key: signature decode: %v", err)
-		return key, false, nil, nil
-	}
-	rawPriv, err := base64.RawStdEncoding.DecodeString(privBytes)
-	if err != nil {
-		logf("decoding wrapped auth-key: priv decode: %v", err)
-		return key, false, nil, nil
-	}
-
-	sig = new(tka.NodeKeySignature)
-	if err := sig.Unserialize([]byte(rawSig)); err != nil {
-		logf("decoding wrapped auth-key: signature: %v", err)
-		return key, false, nil, nil
-	}
-	priv = ed25519.PrivateKey(rawPriv)
-
-	return authKey, true, sig, priv
-}
-
 func addLBHeader(req *http.Request, nodeKey key.NodePublic) {
 	if !nodeKey.IsZero() {
 		req.Header.Add(tailcfg.LBHeader, nodeKey.String())

control/controlclient/direct_test.go

@@ -4,7 +4,6 @@
 package controlclient
 
 import (
-	"crypto/ed25519"
 	"encoding/json"
 	"net/http"
 	"net/http/httptest"
@@ -147,42 +146,3 @@ func TestTsmpPing(t *testing.T) {
 		t.Fatal(err)
 	}
 }
-
-func TestDecodeWrappedAuthkey(t *testing.T) {
-	k, isWrapped, sig, priv := decodeWrappedAuthkey("tskey-32mjsdkdsffds9o87dsfkjlh", nil)
-	if want := "tskey-32mjsdkdsffds9o87dsfkjlh"; k != want {
-		t.Errorf("decodeWrappedAuthkey(<unwrapped-key>).key = %q, want %q", k, want)
-	}
-	if isWrapped {
-		t.Error("decodeWrappedAuthkey(<unwrapped-key>).isWrapped = true, want false")
-	}
-	if sig != nil {
-		t.Errorf("decodeWrappedAuthkey(<unwrapped-key>).sig = %v, want nil", sig)
-	}
-	if priv != nil {
-		t.Errorf("decodeWrappedAuthkey(<unwrapped-key>).priv = %v, want nil", priv)
-	}
-
-	k, isWrapped, sig, priv = decodeWrappedAuthkey("tskey-auth-k7UagY1CNTRL-ZZZZZ--TLpAEDA1ggnXuw4/fWnNWUwcoOjLemhOvml1juMl5lhLmY5sBUsj8EWEAfL2gdeD9g8VDw5tgcxCiHGlEb67BgU2DlFzZApi4LheLJraA+pYjTGChVhpZz1iyiBPD+U2qxDQAbM3+WFY0EBlggxmVqG53Hu0Rg+KmHJFMlUhfgzo+AQP6+Kk9GzvJJOs4-k36RdoSFqaoARfQo0UncHAV0t3YTqrkD5r/z2jTrE43GZWobnce7RGD4qYckUyVSF+DOj4BA/r4qT0bO8kk6zg", nil)
-	if want := "tskey-auth-k7UagY1CNTRL-ZZZZZ"; k != want {
-		t.Errorf("decodeWrappedAuthkey(<wrapped-key>).key = %q, want %q", k, want)
-	}
-	if !isWrapped {
-		t.Error("decodeWrappedAuthkey(<wrapped-key>).isWrapped = false, want true")
-	}
-
-	if sig == nil {
-		t.Fatal("decodeWrappedAuthkey(<wrapped-key>).sig = nil, want non-nil signature")
-	}
-	sigHash := sig.SigHash()
-	if !ed25519.Verify(sig.KeyID, sigHash[:], sig.Signature) {
-		t.Error("signature failed to verify")
-	}
-
-	// Make sure the private is correct by using it.
-	someSig := ed25519.Sign(priv, []byte{1, 2, 3, 4})
-	if !ed25519.Verify(sig.WrappingPubkey, []byte{1, 2, 3, 4}, someSig) {
-		t.Error("failed to use priv")
-	}
-
-}

control/controlhttp/client.go

@@ -46,6 +46,7 @@ import (
 	"tailscale.com/net/sockstats"
 	"tailscale.com/net/tlsdial"
 	"tailscale.com/net/tshttpproxy"
+	"tailscale.com/syncs"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tstime"
 	"tailscale.com/util/multierr"
@@ -497,11 +498,9 @@ func (a *Dialer) tryURLUpgrade(ctx context.Context, u *url.URL, addr netip.Addr,
 	tr.DisableCompression = true
 
 	// (mis)use httptrace to extract the underlying net.Conn from the
-	// transport. We make exactly 1 request using this transport, so
-	// there will be exactly 1 GotConn call. Additionally, the
-	// transport handles 101 Switching Protocols correctly, such that
-	// the Conn will not be reused or kept alive by the transport once
-	// the response has been handed back from RoundTrip.
+	// transport. The transport handles 101 Switching Protocols correctly,
+	// such that the Conn will not be reused or kept alive by the transport
+	// once the response has been handed back from RoundTrip.
 	//
 	// In theory, the machinery of net/http should make it such that
 	// the trace callback happens-before we get the response, but
@@ -517,10 +516,16 @@ func (a *Dialer) tryURLUpgrade(ctx context.Context, u *url.URL, addr netip.Addr,
 	// unexpected EOFs...), and we're bound to forget someday and
 	// introduce a protocol optimization at a higher level that starts
 	// eagerly transmitting from the server.
-	connCh := make(chan net.Conn, 1)
+	var lastConn syncs.AtomicValue[net.Conn]
 	trace := httptrace.ClientTrace{
+		// Even though we only make a single HTTP request which should
+		// require a single connection, the context (with the attached
+		// trace configuration) might be used by our custom dialer to
+		// make other HTTP requests (e.g. BootstrapDNS). We only care
+		// about the last connection made, which should be the one to
+		// the control server.
 		GotConn: func(info httptrace.GotConnInfo) {
-			connCh <- info.Conn
+			lastConn.Store(info.Conn)
 		},
 	}
 	ctx = httptrace.WithClientTrace(ctx, &trace)
@@ -548,11 +553,7 @@ func (a *Dialer) tryURLUpgrade(ctx context.Context, u *url.URL, addr netip.Addr,
 	// is still a read buffer attached to it within resp.Body. So, we
 	// must direct I/O through resp.Body, but we can still use the
 	// underlying net.Conn for stuff like deadlines.
-	var switchedConn net.Conn
-	select {
-	case switchedConn = <-connCh:
-	default:
-	}
+	switchedConn := lastConn.Load()
 	if switchedConn == nil {
 		resp.Body.Close()
 		return nil, fmt.Errorf("httptrace didn't provide a connection")

control/controlhttp/client_js.go

@@ -10,7 +10,7 @@ import (
 	"net"
 	"net/url"
 
-	"nhooyr.io/websocket"
+	"github.com/coder/websocket"
 	"tailscale.com/control/controlbase"
 	"tailscale.com/net/wsconn"
 )

control/controlhttp/http_test.go

@@ -11,10 +11,12 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"net/http/httptest"
 	"net/http/httputil"
 	"net/netip"
 	"net/url"
 	"runtime"
+	"slices"
 	"strconv"
 	"sync"
 	"testing"
@@ -41,6 +43,8 @@ type httpTestParam struct {
 	makeHTTPHangAfterUpgrade bool
 
 	doEarlyWrite bool
+
+	httpInDial bool
 }
 
 func TestControlHTTP(t *testing.T) {
@@ -120,6 +124,12 @@ func TestControlHTTP(t *testing.T) {
 			name:         "early_write",
 			doEarlyWrite: true,
 		},
+		// Dialer needed to make another HTTP request along the way (e.g. to
+		// resolve the hostname via BootstrapDNS).
+		{
+			name:       "http_request_in_dial",
+			httpInDial: true,
+		},
 	}
 
 	for _, test := range tests {
@@ -217,6 +227,29 @@ func testControlHTTP(t *testing.T, param httpTestParam) {
 		Clock:                clock,
 	}
 
+	if param.httpInDial {
+		// Spin up a separate server to get a different port on localhost.
+		secondServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { return }))
+		defer secondServer.Close()
+
+		prev := a.Dialer
+		a.Dialer = func(ctx context.Context, network, addr string) (net.Conn, error) {
+			ctx, cancel := context.WithTimeout(ctx, time.Second)
+			defer cancel()
+			req, err := http.NewRequestWithContext(ctx, "GET", secondServer.URL, nil)
+			if err != nil {
+				t.Errorf("http.NewRequest: %v", err)
+			}
+			r, err := http.DefaultClient.Do(req)
+			if err != nil {
+				t.Errorf("http.Get: %v", err)
+			}
+			r.Body.Close()
+
+			return prev(ctx, network, addr)
+		}
+	}
+
 	if proxy != nil {
 		proxyEnv := proxy.Start(t)
 		defer proxy.Close()
@@ -238,6 +271,7 @@ func testControlHTTP(t *testing.T, param httpTestParam) {
 		t.Fatalf("dialing controlhttp: %v", err)
 	}
 	defer conn.Close()
+
 	si := <-sch
 	if si.conn != nil {
 		defer si.conn.Close()
@@ -266,6 +300,19 @@ func testControlHTTP(t *testing.T, param httpTestParam) {
 			t.Errorf("early write = %q; want %q", buf, earlyWriteMsg)
 		}
 	}
+
+	// When no proxy is used, the RemoteAddr of the returned connection should match
+	// one of the listeners of the test server.
+	if proxy == nil {
+		var expectedAddrs []string
+		for _, ln := range []net.Listener{httpLn, httpsLn} {
+			expectedAddrs = append(expectedAddrs, fmt.Sprintf("127.0.0.1:%d", ln.Addr().(*net.TCPAddr).Port))
+			expectedAddrs = append(expectedAddrs, fmt.Sprintf("[::1]:%d", ln.Addr().(*net.TCPAddr).Port))
+		}
+		if !slices.Contains(expectedAddrs, conn.RemoteAddr().String()) {
+			t.Errorf("unexpected remote addr: %s, want %s", conn.RemoteAddr(), expectedAddrs)
+		}
+	}
 }
 
 type serverResult struct {

control/controlhttp/server.go

@@ -14,7 +14,7 @@ import (
 	"strings"
 	"time"
 
-	"nhooyr.io/websocket"
+	"github.com/coder/websocket"
 	"tailscale.com/control/controlbase"
 	"tailscale.com/net/netutil"
 	"tailscale.com/net/wsconn"

control/controlknobs/controlknobs.go

@@ -19,10 +19,6 @@ type Knobs struct {
 	// DisableUPnP indicates whether to attempt UPnP mapping.
 	DisableUPnP atomic.Bool
 
-	// DisableDRPO is whether control says to disable the
-	// DERP route optimization (Issue 150).
-	DisableDRPO atomic.Bool
-
 	// KeepFullWGConfig is whether we should disable the lazy wireguard
 	// programming and instead give WireGuard the full netmap always, even for
 	// idle peers.
@@ -99,6 +95,14 @@ type Knobs struct {
 	// We began creating this rule on 2024-06-14, and this knob
 	// allows us to disable the new behavior remotely if needed.
 	DisableLocalDNSOverrideViaNRPT atomic.Bool
+
+	// DisableCryptorouting indicates that the node should not use the
+	// magicsock crypto routing feature.
+	DisableCryptorouting atomic.Bool
+
+	// DisableCaptivePortalDetection is whether the node should not perform captive portal detection
+	// automatically when the network state changes.
+	DisableCaptivePortalDetection atomic.Bool
 }
 
 // UpdateFromNodeAttributes updates k (if non-nil) based on the provided self
@@ -110,7 +114,6 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
 	has := capMap.Contains
 	var (
 		keepFullWG                           = has(tailcfg.NodeAttrDebugDisableWGTrim)
-		disableDRPO                          = has(tailcfg.NodeAttrDebugDisableDRPO)
 		disableUPnP                          = has(tailcfg.NodeAttrDisableUPnP)
 		randomizeClientPort                  = has(tailcfg.NodeAttrRandomizeClientPort)
 		disableDeltaUpdates                  = has(tailcfg.NodeAttrDisableDeltaUpdates)
@@ -127,6 +130,8 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
 		userDialUseRoutes                    = has(tailcfg.NodeAttrUserDialUseRoutes)
 		disableSplitDNSWhenNoCustomResolvers = has(tailcfg.NodeAttrDisableSplitDNSWhenNoCustomResolvers)
 		disableLocalDNSOverrideViaNRPT       = has(tailcfg.NodeAttrDisableLocalDNSOverrideViaNRPT)
+		disableCryptorouting                 = has(tailcfg.NodeAttrDisableMagicSockCryptoRouting)
+		disableCaptivePortalDetection        = has(tailcfg.NodeAttrDisableCaptivePortalDetection)
 	)
 
 	if has(tailcfg.NodeAttrOneCGNATEnable) {
@@ -136,7 +141,6 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
 	}
 
 	k.KeepFullWGConfig.Store(keepFullWG)
-	k.DisableDRPO.Store(disableDRPO)
 	k.DisableUPnP.Store(disableUPnP)
 	k.RandomizeClientPort.Store(randomizeClientPort)
 	k.OneCGNAT.Store(oneCGNAT)
@@ -153,6 +157,8 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
 	k.UserDialUseRoutes.Store(userDialUseRoutes)
 	k.DisableSplitDNSWhenNoCustomResolvers.Store(disableSplitDNSWhenNoCustomResolvers)
 	k.DisableLocalDNSOverrideViaNRPT.Store(disableLocalDNSOverrideViaNRPT)
+	k.DisableCryptorouting.Store(disableCryptorouting)
+	k.DisableCaptivePortalDetection.Store(disableCaptivePortalDetection)
 }
 
 // AsDebugJSON returns k as something that can be marshalled with json.Marshal
@@ -163,7 +169,6 @@ func (k *Knobs) AsDebugJSON() map[string]any {
 	}
 	return map[string]any{
 		"DisableUPnP":                          k.DisableUPnP.Load(),
-		"DisableDRPO":                          k.DisableDRPO.Load(),
 		"KeepFullWGConfig":                     k.KeepFullWGConfig.Load(),
 		"RandomizeClientPort":                  k.RandomizeClientPort.Load(),
 		"OneCGNAT":                             k.OneCGNAT.Load(),
@@ -180,5 +185,7 @@ func (k *Knobs) AsDebugJSON() map[string]any {
 		"UserDialUseRoutes":                    k.UserDialUseRoutes.Load(),
 		"DisableSplitDNSWhenNoCustomResolvers": k.DisableSplitDNSWhenNoCustomResolvers.Load(),
 		"DisableLocalDNSOverrideViaNRPT":       k.DisableLocalDNSOverrideViaNRPT.Load(),
+		"DisableCryptorouting":                 k.DisableCryptorouting.Load(),
+		"DisableCaptivePortalDetection":        k.DisableCaptivePortalDetection.Load(),
 	}
 }

derp/derp.go

@@ -83,9 +83,16 @@ const (
 	// a bug).
 	framePeerGone = frameType(0x08) // 32B pub key of peer that's gone + 1 byte reason
 
-	// framePeerPresent is like framePeerGone, but for other
-	// members of the DERP region when they're meshed up together.
-	framePeerPresent = frameType(0x09) // 32B pub key of peer that's connected + optional 18B ip:port (16 byte IP + 2 byte BE uint16 port)
+	// framePeerPresent is like framePeerGone, but for other members of the DERP
+	// region when they're meshed up together.
+	//
+	// The message is at least 32 bytes (the public key of the peer that's
+	// connected). If there are at least 18 bytes remaining after that, it's the
+	// 16 byte IP + 2 byte BE uint16 port of the client. If there's another byte
+	// remaining after that, it's a PeerPresentFlags byte.
+	// While current servers send 41 bytes, old servers will send fewer, and newer
+	// servers might send more.
+	framePeerPresent = frameType(0x09)
 
 	// frameWatchConns is how one DERP node in a regional mesh
 	// subscribes to the others in the region.
@@ -124,8 +131,22 @@ const (
 type PeerGoneReasonType byte
 
 const (
-	PeerGoneReasonDisconnected = PeerGoneReasonType(0x00) // peer disconnected from this server
-	PeerGoneReasonNotHere      = PeerGoneReasonType(0x01) // server doesn't know about this peer, unexpected
+	PeerGoneReasonDisconnected  = PeerGoneReasonType(0x00) // peer disconnected from this server
+	PeerGoneReasonNotHere       = PeerGoneReasonType(0x01) // server doesn't know about this peer, unexpected
+	PeerGoneReasonMeshConnBroke = PeerGoneReasonType(0xf0) // invented by Client.RunWatchConnectionLoop on disconnect; not sent on the wire
+)
+
+// PeerPresentFlags is an optional byte of bit flags sent after a framePeerPresent message.
+//
+// For a modern server, the value should always be non-zero. If the value is zero,
+// that means the server doesn't support this field.
+type PeerPresentFlags byte
+
+// PeerPresentFlags bits.
+const (
+	PeerPresentIsRegular  = 1 << 0
+	PeerPresentIsMeshPeer = 1 << 1
+	PeerPresentIsProber   = 1 << 2
 )
 
 var bin = binary.BigEndian

derp/derp_client.go

@@ -368,6 +368,8 @@ type PeerPresentMessage struct {
 	Key key.NodePublic
 	// IPPort is the remote IP and port of the client.
 	IPPort netip.AddrPort
+	// Flags is a bitmask of info about the client.
+	Flags PeerPresentFlags
 }
 
 func (PeerPresentMessage) msg() {}
@@ -547,18 +549,33 @@ func (c *Client) recvTimeout(timeout time.Duration) (m ReceivedMessage, err erro
 			return pg, nil
 
 		case framePeerPresent:
-			if n < keyLen {
+			remain := b
+			chunk, remain, ok := cutLeadingN(remain, keyLen)
+			if !ok {
 				c.logf("[unexpected] dropping short peerPresent frame from DERP server")
 				continue
 			}
 			var msg PeerPresentMessage
-			msg.Key = key.NodePublicFromRaw32(mem.B(b[:keyLen]))
-			if n >= keyLen+16+2 {
-				msg.IPPort = netip.AddrPortFrom(
-					netip.AddrFrom16([16]byte(b[keyLen:keyLen+16])).Unmap(),
-					binary.BigEndian.Uint16(b[keyLen+16:keyLen+16+2]),
-				)
+			msg.Key = key.NodePublicFromRaw32(mem.B(chunk))
+
+			const ipLen = 16
+			const portLen = 2
+			chunk, remain, ok = cutLeadingN(remain, ipLen+portLen)
+			if !ok {
+				// Older server which didn't send the IP.
+				return msg, nil
 			}
+			msg.IPPort = netip.AddrPortFrom(
+				netip.AddrFrom16([16]byte(chunk[:ipLen])).Unmap(),
+				binary.BigEndian.Uint16(chunk[ipLen:]),
+			)
+
+			chunk, _, ok = cutLeadingN(remain, 1)
+			if !ok {
+				// Older server which doesn't send PeerPresentFlags.
+				return msg, nil
+			}
+			msg.Flags = PeerPresentFlags(chunk[0])
 			return msg, nil
 
 		case frameRecvPacket:
@@ -636,3 +653,10 @@ func (c *Client) LocalAddr() (netip.AddrPort, error) {
 	}
 	return netip.ParseAddrPort(a.String())
 }
+
+func cutLeadingN(b []byte, n int) (chunk, remain []byte, ok bool) {
+	if len(b) >= n {
+		return b[:n], b[n:], true
+	}
+	return nil, b, false
+}

derp/derp_server.go

@@ -141,6 +141,8 @@ type Server struct {
 	removePktForwardOther        expvar.Int
 	avgQueueDuration             *uint64          // In milliseconds; accessed atomically
 	tcpRtt                       metrics.LabelMap // histogram
+	meshUpdateBatchSize          *metrics.Histogram
+	meshUpdateLoopCount          *metrics.Histogram
 
 	// verifyClientsLocalTailscaled only accepts client connections to the DERP
 	// server if the clientKey is a known peer in the network, as specified by a
@@ -323,6 +325,8 @@ func NewServer(privateKey key.NodePrivate, logf logger.Logf) *Server {
 		sentTo:               map[key.NodePublic]map[key.NodePublic]int64{},
 		avgQueueDuration:     new(uint64),
 		tcpRtt:               metrics.LabelMap{Label: "le"},
+		meshUpdateBatchSize:  metrics.NewHistogram([]float64{0, 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000}),
+		meshUpdateLoopCount:  metrics.NewHistogram([]float64{0, 1, 2, 5, 10, 20, 50, 100}),
 		keyOfAddr:            map[netip.AddrPort]key.NodePublic{},
 		clock:                tstime.StdClock{},
 	}
@@ -566,7 +570,7 @@ func (s *Server) registerClient(c *sclient) {
 	}
 	s.keyOfAddr[c.remoteIPPort] = c.key
 	s.curClients.Add(1)
-	s.broadcastPeerStateChangeLocked(c.key, c.remoteIPPort, true)
+	s.broadcastPeerStateChangeLocked(c.key, c.remoteIPPort, c.presentFlags(), true)
 }
 
 // broadcastPeerStateChangeLocked enqueues a message to all watchers
@@ -574,12 +578,13 @@ func (s *Server) registerClient(c *sclient) {
 // presence changed.
 //
 // s.mu must be held.
-func (s *Server) broadcastPeerStateChangeLocked(peer key.NodePublic, ipPort netip.AddrPort, present bool) {
+func (s *Server) broadcastPeerStateChangeLocked(peer key.NodePublic, ipPort netip.AddrPort, flags PeerPresentFlags, present bool) {
 	for w := range s.watchers {
 		w.peerStateChange = append(w.peerStateChange, peerConnState{
 			peer:    peer,
 			present: present,
 			ipPort:  ipPort,
+			flags:   flags,
 		})
 		go w.requestMeshUpdate()
 	}
@@ -601,7 +606,7 @@ func (s *Server) unregisterClient(c *sclient) {
 			delete(s.clientsMesh, c.key)
 			s.notePeerGoneFromRegionLocked(c.key)
 		}
-		s.broadcastPeerStateChangeLocked(c.key, netip.AddrPort{}, false)
+		s.broadcastPeerStateChangeLocked(c.key, netip.AddrPort{}, 0, false)
 	case *dupClientSet:
 		c.debugLogf("removed duplicate client")
 		if set.removeClient(c) {
@@ -700,6 +705,7 @@ func (s *Server) addWatcher(c *sclient) {
 			peer:    peer,
 			present: true,
 			ipPort:  ac.remoteIPPort,
+			flags:   ac.presentFlags(),
 		})
 	}
 
@@ -756,7 +762,7 @@ func (s *Server) accept(ctx context.Context, nc Conn, brw *bufio.ReadWriter, rem
 	}
 
 	if c.canMesh {
-		c.meshUpdate = make(chan struct{})
+		c.meshUpdate = make(chan struct{}, 1) // must be buffered; >1 is fine but wasteful
 	}
 	if clientInfo != nil {
 		c.info = *clientInfo
@@ -1141,13 +1147,18 @@ func (c *sclient) requestPeerGoneWrite(peer key.NodePublic, reason PeerGoneReaso
 	}
 }
 
+// requestMeshUpdate notes that a c's peerStateChange has been appended to and
+// should now be written.
+//
+// It does not block. If a meshUpdate is already pending for this client, it
+// does nothing.
 func (c *sclient) requestMeshUpdate() {
 	if !c.canMesh {
 		panic("unexpected requestMeshUpdate")
 	}
 	select {
 	case c.meshUpdate <- struct{}{}:
-	case <-c.done:
+	default:
 	}
 }
 
@@ -1176,6 +1187,10 @@ func (s *Server) verifyClient(ctx context.Context, clientKey key.NodePublic, inf
 			return fmt.Errorf("peer %v not authorized (not found in local tailscaled)", clientKey)
 		}
 		if err != nil {
+			if strings.Contains(err.Error(), "invalid 'addr' parameter") {
+				// Issue 12617
+				return errors.New("tailscaled version is too old (out of sync with derper binary)")
+			}
 			return fmt.Errorf("failed to query local tailscaled status for %v: %w", clientKey, err)
 		}
 	}
@@ -1435,11 +1450,26 @@ type sclient struct {
 	peerGoneLim *rate.Limiter
 }
 
+func (c *sclient) presentFlags() PeerPresentFlags {
+	var f PeerPresentFlags
+	if c.info.IsProber {
+		f |= PeerPresentIsProber
+	}
+	if c.canMesh {
+		f |= PeerPresentIsMeshPeer
+	}
+	if f == 0 {
+		return PeerPresentIsRegular
+	}
+	return f
+}
+
 // peerConnState represents whether a peer is connected to the server
 // or not.
 type peerConnState struct {
 	ipPort  netip.AddrPort // if present, the peer's IP:port
 	peer    key.NodePublic
+	flags   PeerPresentFlags
 	present bool
 }
 
@@ -1613,6 +1643,11 @@ func (c *sclient) sendPong(data [8]byte) error {
 	return err
 }
 
+const (
+	peerGoneFrameLen    = keyLen + 1
+	peerPresentFrameLen = keyLen + 16 + 2 + 1 // 16 byte IP + 2 byte port + 1 byte flags
+)
+
 // sendPeerGone sends a peerGone frame, without flushing.
 func (c *sclient) sendPeerGone(peer key.NodePublic, reason PeerGoneReasonType) error {
 	switch reason {
@@ -1622,7 +1657,7 @@ func (c *sclient) sendPeerGone(peer key.NodePublic, reason PeerGoneReasonType) e
 		c.s.peerGoneNotHereFrames.Add(1)
 	}
 	c.setWriteDeadline()
-	data := make([]byte, 0, keyLen+1)
+	data := make([]byte, 0, peerGoneFrameLen)
 	data = peer.AppendTo(data)
 	data = append(data, byte(reason))
 	if err := writeFrameHeader(c.bw.bw(), framePeerGone, uint32(len(data))); err != nil {
@@ -1634,73 +1669,62 @@ func (c *sclient) sendPeerGone(peer key.NodePublic, reason PeerGoneReasonType) e
 }
 
 // sendPeerPresent sends a peerPresent frame, without flushing.
-func (c *sclient) sendPeerPresent(peer key.NodePublic, ipPort netip.AddrPort) error {
+func (c *sclient) sendPeerPresent(peer key.NodePublic, ipPort netip.AddrPort, flags PeerPresentFlags) error {
 	c.setWriteDeadline()
-	const frameLen = keyLen + 16 + 2
-	if err := writeFrameHeader(c.bw.bw(), framePeerPresent, frameLen); err != nil {
+	if err := writeFrameHeader(c.bw.bw(), framePeerPresent, peerPresentFrameLen); err != nil {
 		return err
 	}
-	payload := make([]byte, frameLen)
+	payload := make([]byte, peerPresentFrameLen)
 	_ = peer.AppendTo(payload[:0])
 	a16 := ipPort.Addr().As16()
 	copy(payload[keyLen:], a16[:])
 	binary.BigEndian.PutUint16(payload[keyLen+16:], ipPort.Port())
+	payload[keyLen+18] = byte(flags)
 	_, err := c.bw.Write(payload)
 	return err
 }
 
-// sendMeshUpdates drains as many mesh peerStateChange entries as
-// possible into the write buffer WITHOUT flushing or otherwise
-// blocking (as it holds c.s.mu while working). If it can't drain them
-// all, it schedules itself to be called again in the future.
+// sendMeshUpdates drains all mesh peerStateChange entries into the write buffer
+// without flushing.
 func (c *sclient) sendMeshUpdates() error {
-	c.s.mu.Lock()
-	defer c.s.mu.Unlock()
+	var lastBatch []peerConnState // memory to best effort reuse
 
-	// allow all happened-before mesh update request goroutines to complete, if
-	// we don't finish the task we'll queue another below.
-drainUpdates:
-	for {
-		select {
-		case <-c.meshUpdate:
-		default:
-			break drainUpdates
+	// takeAll returns c.peerStateChange and empties it.
+	takeAll := func() []peerConnState {
+		c.s.mu.Lock()
+		defer c.s.mu.Unlock()
+		if len(c.peerStateChange) == 0 {
+			return nil
 		}
+		batch := c.peerStateChange
+		if cap(lastBatch) > 16 {
+			lastBatch = nil
+		}
+		c.peerStateChange = lastBatch[:0]
+		return batch
 	}
 
-	writes := 0
-	for _, pcs := range c.peerStateChange {
-		if c.bw.Available() <= frameHeaderLen+keyLen {
-			break
+	for loops := 0; ; loops++ {
+		batch := takeAll()
+		if len(batch) == 0 {
+			c.s.meshUpdateLoopCount.Observe(float64(loops))
+			return nil
 		}
-		var err error
-		if pcs.present {
-			err = c.sendPeerPresent(pcs.peer, pcs.ipPort)
-		} else {
-			err = c.sendPeerGone(pcs.peer, PeerGoneReasonDisconnected)
-		}
-		if err != nil {
-			// Shouldn't happen, though, as we're writing
-			// into available buffer space, not the
-			// network.
-			return err
-		}
-		writes++
-	}
+		c.s.meshUpdateBatchSize.Observe(float64(len(batch)))
 
-	remain := copy(c.peerStateChange, c.peerStateChange[writes:])
-	c.peerStateChange = c.peerStateChange[:remain]
-
-	// Did we manage to write them all into the bufio buffer without flushing?
-	if len(c.peerStateChange) == 0 {
-		if cap(c.peerStateChange) > 16 {
-			c.peerStateChange = nil
+		for _, pcs := range batch {
+			var err error
+			if pcs.present {
+				err = c.sendPeerPresent(pcs.peer, pcs.ipPort, pcs.flags)
+			} else {
+				err = c.sendPeerGone(pcs.peer, PeerGoneReasonDisconnected)
+			}
+			if err != nil {
+				return err
+			}
 		}
-	} else {
-		// Didn't finish in the buffer space provided; schedule a future run.
-		go c.requestMeshUpdate()
+		lastBatch = batch
 	}
-	return nil
 }
 
 // sendPacket writes contents to the client in a RecvPacket frame. If
@@ -1929,6 +1953,8 @@ func (s *Server) ExpVar() expvar.Var {
 		return math.Float64frombits(atomic.LoadUint64(s.avgQueueDuration))
 	}))
 	m.Set("counter_tcp_rtt", &s.tcpRtt)
+	m.Set("counter_mesh_update_batch_size", s.meshUpdateBatchSize)
+	m.Set("counter_mesh_update_loop_count", s.meshUpdateLoopCount)
 	var expvarVersion expvar.String
 	expvarVersion.Set(version.Long())
 	m.Set("version", &expvarVersion)

derp/derp_test.go

@@ -623,7 +623,13 @@ func (tc *testClient) wantPresent(t *testing.T, peers ...key.NodePublic) {
 					}
 				}))
 			}
-			t.Logf("got present with IP %v", m.IPPort)
+			t.Logf("got present with IP %v, flags=%v", m.IPPort, m.Flags)
+			switch m.Flags {
+			case PeerPresentIsMeshPeer, PeerPresentIsRegular:
+				// Okay
+			default:
+				t.Errorf("unexpected PeerPresentIsMeshPeer flags %v", m.Flags)
+			}
 			delete(want, got)
 			if len(want) == 0 {
 				return

derp/derphttp/derphttp_client.go

@@ -381,6 +381,7 @@ func (c *Client) connect(ctx context.Context, caller string) (client *derp.Clien
 	}()
 
 	var node *tailcfg.DERPNode // nil when using c.url to dial
+	var idealNodeInRegion bool
 	switch {
 	case useWebsockets():
 		var urlStr string
@@ -421,6 +422,7 @@ func (c *Client) connect(ctx context.Context, caller string) (client *derp.Clien
 	default:
 		c.logf("%s: connecting to derp-%d (%v)", caller, reg.RegionID, reg.RegionCode)
 		tcpConn, node, err = c.dialRegion(ctx, reg)
+		idealNodeInRegion = err == nil && reg.Nodes[0] == node
 	}
 	if err != nil {
 		return nil, 0, err
@@ -494,6 +496,18 @@ func (c *Client) connect(ctx context.Context, caller string) (client *derp.Clien
 	}
 	req.Header.Set("Upgrade", "DERP")
 	req.Header.Set("Connection", "Upgrade")
+	if !idealNodeInRegion && reg != nil {
+		// This is purely informative for now (2024-07-06) for stats:
+		req.Header.Set("Ideal-Node", reg.Nodes[0].Name)
+		// TODO(bradfitz,raggi): start a time.AfterFunc for 30m-1h or so to
+		// dialNode(reg.Nodes[0]) and see if we can even TCP connect to it. If
+		// so, TLS handshake it as well (which is mixed up in this massive
+		// connect method) and then if it all appears good, grab the mutex, bump
+		// connGen, finish the Upgrade, close the old one, and set a new field
+		// on Client that's like "here's the connect result and connGen for the
+		// next connect that comes in"). Tracking bug for all this is:
+		// https://github.com/tailscale/tailscale/issues/12724
+	}
 
 	if !serverPub.IsZero() && serverProtoVersion != 0 {
 		// parseMetaCert found the server's public key (no TLS

derp/derphttp/derphttp_server.go

@@ -18,6 +18,7 @@ import (
 // following its HTTP request.
 const fastStartHeader = "Derp-Fast-Start"
 
+// Handler returns an http.Handler to be mounted at /derp, serving s.
 func Handler(s *derp.Server) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		// These are installed both here and in cmd/derper. The check here
@@ -79,3 +80,29 @@ func ProbeHandler(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "bogus probe method", http.StatusMethodNotAllowed)
 	}
 }
+
+// ServeNoContent generates the /generate_204 response used by Tailscale's
+// captive portal detection.
+func ServeNoContent(w http.ResponseWriter, r *http.Request) {
+	if challenge := r.Header.Get(NoContentChallengeHeader); challenge != "" {
+		badChar := strings.IndexFunc(challenge, func(r rune) bool {
+			return !isChallengeChar(r)
+		}) != -1
+		if len(challenge) <= 64 && !badChar {
+			w.Header().Set(NoContentResponseHeader, "response "+challenge)
+		}
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func isChallengeChar(c rune) bool {
+	// Semi-randomly chosen as a limited set of valid characters
+	return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') ||
+		('0' <= c && c <= '9') ||
+		c == '.' || c == '-' || c == '_'
+}
+
+const (
+	NoContentChallengeHeader = "X-Tailscale-Challenge"
+	NoContentResponseHeader  = "X-Tailscale-Response"
+)

derp/derphttp/derphttp_test.go

@@ -11,7 +11,6 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptest"
-	"net/netip"
 	"sync"
 	"testing"
 	"time"
@@ -299,13 +298,13 @@ func TestBreakWatcherConnRecv(t *testing.T) {
 	go func() {
 		defer wg.Done()
 		var peers int
-		add := func(k key.NodePublic, _ netip.AddrPort) {
-			t.Logf("add: %v", k.ShortString())
+		add := func(m derp.PeerPresentMessage) {
+			t.Logf("add: %v", m.Key.ShortString())
 			peers++
 			// Signal that the watcher has run
 			watcherChan <- peers
 		}
-		remove := func(k key.NodePublic) { t.Logf("remove: %v", k.ShortString()); peers-- }
+		remove := func(m derp.PeerGoneMessage) { t.Logf("remove: %v", m.Peer.ShortString()); peers-- }
 
 		watcher1.RunWatchConnectionLoop(ctx, serverPrivateKey1.Public(), t.Logf, add, remove)
 	}()
@@ -370,15 +369,15 @@ func TestBreakWatcherConn(t *testing.T) {
 	go func() {
 		defer wg.Done()
 		var peers int
-		add := func(k key.NodePublic, _ netip.AddrPort) {
-			t.Logf("add: %v", k.ShortString())
+		add := func(m derp.PeerPresentMessage) {
+			t.Logf("add: %v", m.Key.ShortString())
 			peers++
 			// Signal that the watcher has run
 			watcherChan <- peers
 			// Wait for breaker to run
 			<-breakerChan
 		}
-		remove := func(k key.NodePublic) { t.Logf("remove: %v", k.ShortString()); peers-- }
+		remove := func(m derp.PeerGoneMessage) { t.Logf("remove: %v", m.Peer.ShortString()); peers-- }
 
 		watcher1.RunWatchConnectionLoop(ctx, serverPrivateKey1.Public(), t.Logf, add, remove)
 	}()
@@ -407,8 +406,8 @@ func TestBreakWatcherConn(t *testing.T) {
 	}
 }
 
-func noopAdd(key.NodePublic, netip.AddrPort) {}
-func noopRemove(key.NodePublic)              {}
+func noopAdd(derp.PeerPresentMessage) {}
+func noopRemove(derp.PeerGoneMessage) {}
 
 func TestRunWatchConnectionLoopServeConnect(t *testing.T) {
 	defer func() { testHookWatchLookConnectResult = nil }()

derp/derphttp/mesh_client.go

@@ -5,7 +5,6 @@ package derphttp
 
 import (
 	"context"
-	"net/netip"
 	"sync"
 	"time"
 
@@ -35,9 +34,14 @@ var testHookWatchLookConnectResult func(connectError error, wasSelfConnect bool)
 // To force RunWatchConnectionLoop to return quickly, its ctx needs to be
 // closed, and c itself needs to be closed.
 //
-// It is a fatal error to call this on an already-started Client withoutq having
+// It is a fatal error to call this on an already-started Client without having
 // initialized Client.WatchConnectionChanges to true.
-func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key.NodePublic, infoLogf logger.Logf, add func(key.NodePublic, netip.AddrPort), remove func(key.NodePublic)) {
+//
+// If the DERP connection breaks and reconnects, remove will be called for all
+// previously seen peers, with Reason type PeerGoneReasonSynthetic. Those
+// clients are likely still connected and their add message will appear after
+// reconnect.
+func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key.NodePublic, infoLogf logger.Logf, add func(derp.PeerPresentMessage), remove func(derp.PeerGoneMessage)) {
 	if !c.WatchConnectionChanges {
 		if c.isStarted() {
 			panic("invalid use of RunWatchConnectionLoop on already-started Client without setting Client.RunWatchConnectionLoop")
@@ -62,7 +66,7 @@ func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key
 		}
 		logf("reconnected; clearing %d forwarding mappings", len(present))
 		for k := range present {
-			remove(k)
+			remove(derp.PeerGoneMessage{Peer: k, Reason: derp.PeerGoneReasonMeshConnBroke})
 		}
 		present = map[key.NodePublic]bool{}
 	}
@@ -84,13 +88,7 @@ func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key
 	})
 	defer timer.Stop()
 
-	updatePeer := func(k key.NodePublic, ipPort netip.AddrPort, isPresent bool) {
-		if isPresent {
-			add(k, ipPort)
-		} else {
-			remove(k)
-		}
-
+	updatePeer := func(k key.NodePublic, isPresent bool) {
 		mu.Lock()
 		defer mu.Unlock()
 		if isPresent {
@@ -148,7 +146,8 @@ func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key
 			}
 			switch m := m.(type) {
 			case derp.PeerPresentMessage:
-				updatePeer(m.Key, m.IPPort, true)
+				add(m)
+				updatePeer(m.Key, true)
 			case derp.PeerGoneMessage:
 				switch m.Reason {
 				case derp.PeerGoneReasonDisconnected:
@@ -160,7 +159,8 @@ func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key
 					logf("Recv: peer %s not at server %s for unknown reason %v",
 						key.NodePublic(m.Peer).ShortString(), c.ServerPublicKey().ShortString(), m.Reason)
 				}
-				updatePeer(key.NodePublic(m.Peer), netip.AddrPort{}, false)
+				remove(m)
+				updatePeer(m.Peer, false)
 			default:
 				continue
 			}

derp/derphttp/websocket.go

@@ -10,7 +10,7 @@ import (
 	"log"
 	"net"
 
-	"nhooyr.io/websocket"
+	"github.com/coder/websocket"
 	"tailscale.com/net/wsconn"
 )
 

derp/xdp/headers/update.go

@@ -1,6 +1,8 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// The update program fetches the libbpf headers from the libbpf GitHub repository
+// and writes them to disk.
 package main
 
 import (

derp/xdp/xdp.go

@@ -1,6 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// Package xdp contains the XDP STUN program.
 package xdp
 
 // XDPAttachFlags represents how XDP program will be attached to interface. This

derp/xdp/xdp_linux.go

@@ -14,6 +14,7 @@ import (
 	"github.com/cilium/ebpf"
 	"github.com/cilium/ebpf/link"
 	"github.com/prometheus/client_golang/prometheus"
+	"tailscale.com/util/multierr"
 )
 
 //go:generate go run github.com/cilium/ebpf/cmd/bpf2go -type config -type counters_key -type counter_key_af -type counter_key_packets_bytes_action -type counter_key_prog_end bpf xdp.c -- -I headers
@@ -27,6 +28,7 @@ type STUNServer struct {
 	metrics  *stunServerMetrics
 	dstPort  int
 	dropSTUN bool
+	link     link.Link
 }
 
 //lint:ignore U1000 used in xdp_linux_test.go, which has a build tag
@@ -87,7 +89,7 @@ func NewSTUNServer(config *STUNServerConfig, opts ...STUNServerOption) (*STUNSer
 	if err != nil {
 		return nil, fmt.Errorf("error finding device: %w", err)
 	}
-	_, err = link.AttachXDP(link.XDPOptions{
+	link, err := link.AttachXDP(link.XDPOptions{
 		Program:   objs.XdpProgFunc,
 		Interface: iface.Index,
 		Flags:     link.XDPAttachFlags(config.AttachFlags),
@@ -95,6 +97,7 @@ func NewSTUNServer(config *STUNServerConfig, opts ...STUNServerOption) (*STUNSer
 	if err != nil {
 		return nil, fmt.Errorf("error attaching XDP program to dev: %w", err)
 	}
+	server.link = link
 	return server, nil
 }
 
@@ -102,7 +105,12 @@ func NewSTUNServer(config *STUNServerConfig, opts ...STUNServerOption) (*STUNSer
 func (s *STUNServer) Close() error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	return s.objs.Close()
+	var errs []error
+	if s.link != nil {
+		errs = append(errs, s.link.Close())
+	}
+	errs = append(errs, s.objs.Close())
+	return multierr.New(errs...)
 }
 
 type stunServerMetrics struct {

envknob/envknob.go

@@ -36,13 +36,19 @@ import (
 )
 
 var (
-	mu          sync.Mutex
-	set         = map[string]string{}
-	regStr      = map[string]*string{}
-	regBool     = map[string]*bool{}
-	regOptBool  = map[string]*opt.Bool{}
+	mu sync.Mutex
+	// +checklocks:mu
+	set = map[string]string{}
+	// +checklocks:mu
+	regStr = map[string]*string{}
+	// +checklocks:mu
+	regBool = map[string]*bool{}
+	// +checklocks:mu
+	regOptBool = map[string]*opt.Bool{}
+	// +checklocks:mu
 	regDuration = map[string]*time.Duration{}
-	regInt      = map[string]*int{}
+	// +checklocks:mu
+	regInt = map[string]*int{}
 )
 
 func noteEnv(k, v string) {
@@ -51,6 +57,7 @@ func noteEnv(k, v string) {
 	noteEnvLocked(k, v)
 }
 
+// +checklocks:mu
 func noteEnvLocked(k, v string) {
 	if v != "" {
 		set[k] = v
@@ -202,6 +209,7 @@ func RegisterInt(envVar string) func() int {
 	return func() int { return *p }
 }
 
+// +checklocks:mu
 func setBoolLocked(p *bool, envVar, val string) {
 	noteEnvLocked(envVar, val)
 	if val == "" {
@@ -215,6 +223,7 @@ func setBoolLocked(p *bool, envVar, val string) {
 	}
 }
 
+// +checklocks:mu
 func setOptBoolLocked(p *opt.Bool, envVar, val string) {
 	noteEnvLocked(envVar, val)
 	if val == "" {
@@ -228,6 +237,7 @@ func setOptBoolLocked(p *opt.Bool, envVar, val string) {
 	p.Set(b)
 }
 
+// +checklocks:mu
 func setDurationLocked(p *time.Duration, envVar, val string) {
 	noteEnvLocked(envVar, val)
 	if val == "" {
@@ -241,6 +251,7 @@ func setDurationLocked(p *time.Duration, envVar, val string) {
 	}
 }
 
+// +checklocks:mu
 func setIntLocked(p *int, envVar, val string) {
 	noteEnvLocked(envVar, val)
 	if val == "" {

flake.nix

@@ -120,4 +120,4 @@
   in
     flake-utils.lib.eachDefaultSystem (system: flakeForSystem nixpkgs system);
 }
-# nix-direnv cache busting line: sha256-ye8puuEDd/CRSy/AHrtLdKVxVASJAdpt6bW3jU2OUvw=
+# nix-direnv cache busting line: sha256-M5e5dE1gGW3ly94r3SxCsBmVwbBmhVtaVDW691vxG/8=

go.mod

@@ -4,8 +4,6 @@ go 1.22.0
 
 require (
 	filippo.io/mkcert v1.4.4
-	fybrik.io/crdoc v0.6.3
-	github.com/Masterminds/squirrel v1.5.4
 	github.com/akutz/memconn v0.1.0
 	github.com/alexbrainman/sspi v0.0.0-20231016080023-1a75b4708caa
 	github.com/andybalholm/brotli v1.1.0
@@ -17,21 +15,22 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/ssm v1.44.7
 	github.com/bramvdbogaerde/go-scp v1.4.0
 	github.com/cilium/ebpf v0.15.0
+	github.com/coder/websocket v1.8.12
 	github.com/coreos/go-iptables v0.7.1-0.20240112124308-65c67c9f46e6
 	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
-	github.com/creack/pty v1.1.21
+	github.com/creack/pty v1.1.23
 	github.com/dave/courtney v0.4.0
-	github.com/dave/jennifer v1.7.0
 	github.com/dave/patsy v0.0.0-20210517141501-957256f50cba
 	github.com/dblohm7/wingoes v0.0.0-20240119213807-a09d6be7affa
 	github.com/digitalocean/go-smbios v0.0.0-20180907143718-390a4f403a8e
 	github.com/distribution/reference v0.6.0
 	github.com/djherbis/times v1.6.0
 	github.com/dsnet/try v0.0.3
+	github.com/elastic/crd-ref-docs v0.0.12
 	github.com/evanw/esbuild v0.19.11
 	github.com/frankban/quicktest v1.14.6
 	github.com/fxamacker/cbor/v2 v2.6.0
-	github.com/gaissmai/bart v0.4.1
+	github.com/gaissmai/bart v0.11.1
 	github.com/go-json-experiment/json v0.0.0-20231102232822-2e55bd4e08b0
 	github.com/go-logr/zapr v1.3.0
 	github.com/go-ole/go-ole v1.3.0
@@ -41,11 +40,11 @@ require (
 	github.com/golangci/golangci-lint v1.52.2
 	github.com/google/go-cmp v0.6.0
 	github.com/google/go-containerregistry v0.18.0
+	github.com/google/gopacket v1.1.19
 	github.com/google/nftables v0.2.1-0.20240414091927-5e242ec57806
 	github.com/google/uuid v1.6.0
 	github.com/goreleaser/nfpm/v2 v2.33.1
 	github.com/hdevalence/ed25519consensus v0.2.0
-	github.com/iancoleman/strcase v0.3.0
 	github.com/illarion/gonotify v1.0.1
 	github.com/inetaf/tcpproxy v0.0.0-20240214030015-3ce58045626c
 	github.com/insomniacslk/dhcp v0.0.0-20231206064809-8c70d406f6d2
@@ -78,43 +77,41 @@ require (
 	github.com/tailscale/golang-x-crypto v0.0.0-20240604161659-3fde5e568aa4
 	github.com/tailscale/goupnp v1.0.1-0.20210804011211-c64d0f06ea05
 	github.com/tailscale/hujson v0.0.0-20221223112325-20486734a56a
-	github.com/tailscale/mkctr v0.0.0-20240102155253-bf50773ba734
+	github.com/tailscale/mkctr v0.0.0-20240628074852-17ca944da6ba
 	github.com/tailscale/netlink v1.1.1-0.20211101221916-cabfb018fe85
 	github.com/tailscale/peercred v0.0.0-20240214030740-b535050b2aa4
 	github.com/tailscale/web-client-prebuilt v0.0.0-20240226180453-5db17b287bf1
 	github.com/tailscale/wf v0.0.0-20240214030419-6fbb0a674ee6
-	github.com/tailscale/wireguard-go v0.0.0-20240429185444-03c5a0ccf754
-	github.com/tailscale/xnet v0.0.0-20240117122442-62b9a7c569f9
+	github.com/tailscale/wireguard-go v0.0.0-20240731203015-71393c576b98
+	github.com/tailscale/xnet v0.0.0-20240729143630-8497ac4dab2e
 	github.com/tc-hib/winres v0.2.1
 	github.com/tcnksm/go-httpstat v0.2.0
 	github.com/toqueteos/webbrowser v1.2.0
 	github.com/u-root/u-root v0.12.0
 	github.com/vishvananda/netlink v1.2.1-beta.2
 	github.com/vishvananda/netns v0.0.4
-	go.uber.org/zap v1.26.0
+	go.uber.org/zap v1.27.0
 	go4.org/mem v0.0.0-20220726221520-4f986261bf13
 	go4.org/netipx v0.0.0-20231129151722-fdeea329fbba
-	golang.org/x/crypto v0.24.0
+	golang.org/x/crypto v0.25.0
 	golang.org/x/exp v0.0.0-20240119083558-1b970713d09a
-	golang.org/x/mod v0.18.0
-	golang.org/x/net v0.26.0
+	golang.org/x/mod v0.19.0
+	golang.org/x/net v0.27.0
 	golang.org/x/oauth2 v0.16.0
 	golang.org/x/sync v0.7.0
-	golang.org/x/sys v0.21.0
-	golang.org/x/term v0.21.0
+	golang.org/x/sys v0.22.0
+	golang.org/x/term v0.22.0
 	golang.org/x/time v0.5.0
-	golang.org/x/tools v0.22.0
+	golang.org/x/tools v0.23.0
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2
 	golang.zx2c4.com/wireguard/windows v0.5.3
 	gopkg.in/square/go-jose.v2 v2.6.0
-	gvisor.dev/gvisor v0.0.0-20240306221502-ee1e1f6070e3
+	gvisor.dev/gvisor v0.0.0-20240722211153-64c016c92987
 	honnef.co/go/tools v0.4.6
-	k8s.io/api v0.30.1
-	k8s.io/apimachinery v0.30.1
-	k8s.io/apiserver v0.30.1
-	k8s.io/client-go v0.30.1
-	modernc.org/sqlite v1.29.10
-	nhooyr.io/websocket v1.8.10
+	k8s.io/api v0.30.3
+	k8s.io/apimachinery v0.30.3
+	k8s.io/apiserver v0.30.3
+	k8s.io/client-go v0.30.3
 	sigs.k8s.io/controller-runtime v0.18.4
 	sigs.k8s.io/controller-tools v0.15.1-0.20240618033008-7824932b0cab
 	sigs.k8s.io/yaml v1.4.0
@@ -122,26 +119,27 @@ require (
 )
 
 require (
+	github.com/Masterminds/sprig v2.22.0+incompatible // indirect
 	github.com/Microsoft/go-winio v0.6.1 // indirect
 	github.com/bits-and-blooms/bitset v1.13.0 // indirect
 	github.com/cyphar/filepath-securejoin v0.2.4 // indirect
 	github.com/dave/astrid v0.0.0-20170323122508-8c2895878b14 // indirect
 	github.com/dave/brenda v1.1.0 // indirect
-	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/docker/go-connections v0.4.0 // indirect
+	github.com/docker/go-units v0.5.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/gobuffalo/flect v1.0.2 // indirect
+	github.com/goccy/go-yaml v1.12.0 // indirect
 	github.com/google/gnostic-models v0.6.9-0.20230804172637-c7be7c783f49 // indirect
+	github.com/google/pprof v0.0.0-20240409012703-83162a5b38cd // indirect
 	github.com/gorilla/securecookie v1.1.2 // indirect
-	github.com/hashicorp/golang-lru/v2 v2.0.7 // indirect
-	github.com/lann/builder v0.0.0-20180802200727-47ae307949d0 // indirect
-	github.com/lann/ps v0.0.0-20150810152359-62de8c46ede0 // indirect
-	github.com/ncruces/go-strftime v0.1.9 // indirect
-	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
-	modernc.org/gc/v3 v3.0.0-20240107210532-573471604cb6 // indirect
-	modernc.org/libc v1.49.3 // indirect
-	modernc.org/mathutil v1.6.0 // indirect
-	modernc.org/memory v1.8.0 // indirect
-	modernc.org/strutil v1.2.0 // indirect
-	modernc.org/token v1.1.0 // indirect
+	github.com/moby/docker-image-spec v1.3.1 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.47.0 // indirect
+	go.opentelemetry.io/otel v1.22.0 // indirect
+	go.opentelemetry.io/otel/metric v1.22.0 // indirect
+	go.opentelemetry.io/otel/trace v1.22.0 // indirect
+	golang.org/x/xerrors v0.0.0-20240716161551-93cc26a95ae9 // indirect
 )
 
 require (
@@ -201,7 +199,7 @@ require (
 	github.com/denis-tingaikin/go-header v0.4.3 // indirect
 	github.com/docker/cli v25.0.0+incompatible // indirect
 	github.com/docker/distribution v2.8.3+incompatible // indirect
-	github.com/docker/docker v25.0.5+incompatible // indirect
+	github.com/docker/docker v26.1.4+incompatible // indirect
 	github.com/docker/docker-credential-helpers v0.8.1 // indirect
 	github.com/emicklei/go-restful/v3 v3.11.2 // indirect
 	github.com/emirpasic/gods v1.18.1 // indirect
@@ -209,7 +207,7 @@ require (
 	github.com/ettle/strcase v0.1.1 // indirect
 	github.com/evanphx/json-patch v5.6.0+incompatible // indirect
 	github.com/evanphx/json-patch/v5 v5.9.0 // indirect
-	github.com/fatih/color v1.16.0 // indirect
+	github.com/fatih/color v1.17.0 // indirect
 	github.com/fatih/structtag v1.2.0 // indirect
 	github.com/firefart/nonamedreturns v1.0.4 // indirect
 	github.com/fsnotify/fsnotify v1.7.0
@@ -218,7 +216,7 @@ require (
 	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
 	github.com/go-git/go-billy/v5 v5.5.0 // indirect
 	github.com/go-git/go-git/v5 v5.11.0 // indirect
-	github.com/go-logr/logr v1.4.1 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
 	github.com/go-openapi/jsonpointer v0.20.2 // indirect
 	github.com/go-openapi/jsonreference v0.20.4 // indirect
 	github.com/go-openapi/swag v0.22.7 // indirect
@@ -260,7 +258,7 @@ require (
 	github.com/hashicorp/go-version v1.6.0 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/hexops/gotextdiff v1.0.3 // indirect
-	github.com/huandu/xstrings v1.4.0 // indirect
+	github.com/huandu/xstrings v1.5.0 // indirect
 	github.com/imdario/mergo v0.3.16 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
@@ -345,14 +343,14 @@ require (
 	github.com/sourcegraph/go-diff v0.7.0 // indirect
 	github.com/spf13/afero v1.9.5 // indirect
 	github.com/spf13/cast v1.6.0 // indirect
-	github.com/spf13/cobra v1.8.0 // indirect
+	github.com/spf13/cobra v1.8.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/spf13/viper v1.16.0 // indirect
 	github.com/ssgreg/nlreturn/v2 v2.2.1 // indirect
 	github.com/stbenjam/no-sprintf-host-port v0.1.1 // indirect
-	github.com/stretchr/objx v0.5.0 // indirect
-	github.com/stretchr/testify v1.8.4
+	github.com/stretchr/objx v0.5.2 // indirect
+	github.com/stretchr/testify v1.9.0
 	github.com/subosito/gotenv v1.4.2 // indirect
 	github.com/t-yuki/gocover-cobertura v0.0.0-20180217150009-aaee18c8195c // indirect
 	github.com/tailscale/go-winio v0.0.0-20231025203758-c4f33415bf55
@@ -376,7 +374,7 @@ require (
 	gitlab.com/digitalxero/go-conventional-commit v1.0.7 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/exp/typeparams v0.0.0-20240119083558-1b970713d09a // indirect
-	golang.org/x/image v0.15.0 // indirect
+	golang.org/x/image v0.18.0 // indirect
 	golang.org/x/text v0.16.0 // indirect
 	gomodules.xyz/jsonpatch/v2 v2.4.0 // indirect
 	google.golang.org/appengine v1.6.8 // indirect
@@ -387,10 +385,10 @@ require (
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1
 	howett.net/plist v1.0.0 // indirect
-	k8s.io/apiextensions-apiserver v0.30.1 // indirect
-	k8s.io/klog/v2 v2.120.1 // indirect
+	k8s.io/apiextensions-apiserver v0.30.3 // indirect
+	k8s.io/klog/v2 v2.130.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20240228011516-70dd3763d340 // indirect
-	k8s.io/utils v0.0.0-20240102154912-e7106e64919e
+	k8s.io/utils v0.0.0-20240711033017-18e509b52bc8
 	mvdan.cc/gofumpt v0.5.0 // indirect
 	mvdan.cc/interfacer v0.0.0-20180901003855-c20040233aed // indirect
 	mvdan.cc/lint v0.0.0-20170908181259-adc824a0674b // indirect

go.mod.sri

@@ -1 +1 @@
-sha256-ye8puuEDd/CRSy/AHrtLdKVxVASJAdpt6bW3jU2OUvw=
+sha256-M5e5dE1gGW3ly94r3SxCsBmVwbBmhVtaVDW691vxG/8=