util/set: add SetOfFunc

Fixes #12901

Signed-off-by: Marwan Sulaiman <marwan@tailscale.com>

Dockerfile

@@ -1,17 +1,6 @@
 # Copyright (c) Tailscale Inc & AUTHORS
 # SPDX-License-Identifier: BSD-3-Clause
 
-############################################################################
-#
-# 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:

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

VERSION.txt

@@ -1 +1 @@
-1.69.0
+1.71.0

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)

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

@@ -49,7 +49,7 @@ 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"`
 }

client/tailscale/localclient.go

@@ -103,7 +103,7 @@ 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.
@@ -933,7 +933,20 @@ 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/derper/depaware.txt

@@ -10,7 +10,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
    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/views
+        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+

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

@@ -77,6 +77,9 @@ spec:
               value: "{{ .Values.apiServerProxyConfig.mode }}"
             - name: PROXY_FIREWALL_MODE
               value: {{ .Values.proxyConfig.firewallMode }}
+            {{- with .Values.operatorConfig.extraEnv }}
+            {{- toYaml . | nindent 12 }}
+            {{- end }}
           volumeMounts:
           - name: oauth
             mountPath: /oauth

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

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 (

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/operator.go

@@ -51,8 +51,7 @@ 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
+// TODO (irbekrm): generate CRD docs from the yamls
 
 func main() {
 	// Required to use our client API. We're fine with the instability since the

cmd/k8s-operator/proxy.go

@@ -11,16 +11,19 @@ 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"
 	tskube "tailscale.com/kube"
+	"tailscale.com/ssh/tailssh"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tsnet"
 	"tailscale.com/util/clientmetric"
@@ -30,10 +33,32 @@ 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")
+
+	// counterSessionRecordingsAttempted counts the number of session recording attempts.
+	counterSessionRecordingsAttempted = clientmetric.NewCounter("k8s_auth_proxy__session_recordings_attempted")
+
+	// counterSessionRecordingsUploaded counts the number of successfully uploaded session recordings.
+	counterSessionRecordingsUploaded = clientmetric.NewCounter("k8s_auth_proxy_session_recordings_uploaded")
+)
 
 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 +122,7 @@ 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 +139,42 @@ 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("/api/v1/namespaces/{namespace}/pods/{pod}/exec", ap.serveExec)
+
 	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 +183,131 @@ 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)))
+}
+
+// serveExec serves 'kubectl exec' requests, optionally configuring the kubectl
+// exec sessions to be recorded.
+func (ap *apiserverProxy) serveExec(w http.ResponseWriter, r *http.Request) {
+	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
+	}
+	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
+	}
+	if r.Method != "POST" || r.Header.Get("Upgrade") != "SPDY/3.1" {
+		msg := "'kubectl exec' session recording is configured, but the request is not over SPDY. Session recording is currently only supported for SPDY based clients"
+		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
+	}
+	spdyH := &spdyHijacker{
+		ts:                ap.ts,
+		req:               r,
+		who:               who,
+		ResponseWriter:    w,
+		log:               ap.log,
+		pod:               r.PathValue("pod"),
+		ns:                r.PathValue("namespace"),
+		addrs:             addrs,
+		failOpen:          failOpen,
+		connectToRecorder: tailssh.ConnectToRecorder,
+	}
+
+	ap.rp.ServeHTTP(spdyH, 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 +367,34 @@ 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
+}

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/recorder.go

@@ -0,0 +1,88 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"sync"
+	"time"
+
+	"github.com/pkg/errors"
+	"tailscale.com/tstime"
+)
+
+// recorder knows how to send the provided bytes to the configured tsrecorder
+// instance in asciinema format.
+type recorder struct {
+	start time.Time
+	clock tstime.Clock
+
+	// failOpen specifies whether the session should be allowed to
+	// continue if writing to the recording fails.
+	failOpen bool
+
+	// backOff is set to true if  we've failed open and should stop
+	// attempting to write to tsrecorder.
+	backOff bool
+
+	mu   sync.Mutex     // guards writes to conn
+	conn io.WriteCloser // connection to a tsrecorder instance
+}
+
+// Write appends timestamp to the provided bytes and sends them to the
+// configured tsrecorder.
+func (rec *recorder) Write(p []byte) (err error) {
+	if len(p) == 0 {
+		return nil
+	}
+	if rec.backOff {
+		return nil
+	}
+	j, err := json.Marshal([]any{
+		rec.clock.Now().Sub(rec.start).Seconds(),
+		"o",
+		string(p),
+	})
+	if err != nil {
+		return fmt.Errorf("error marhalling payload: %w", err)
+	}
+	j = append(j, '\n')
+	if err := rec.writeCastLine(j); err != nil {
+		if !rec.failOpen {
+			return fmt.Errorf("error writing payload to recorder: %w", err)
+		}
+		rec.backOff = true
+	}
+	return nil
+}
+
+func (rec *recorder) Close() error {
+	rec.mu.Lock()
+	defer rec.mu.Unlock()
+	if rec.conn == nil {
+		return nil
+	}
+	err := rec.conn.Close()
+	rec.conn = nil
+	return err
+}
+
+// writeCastLine sends bytes to the tsrecorder. The bytes should be in
+// asciinema format.
+func (rec *recorder) writeCastLine(j []byte) error {
+	rec.mu.Lock()
+	defer rec.mu.Unlock()
+	if rec.conn == nil {
+		return errors.New("recorder closed")
+	}
+	_, err := rec.conn.Write(j)
+	if err != nil {
+		return fmt.Errorf("recorder write error: %w", err)
+	}
+	return nil
+}

cmd/k8s-operator/spdy-frame.go

@@ -0,0 +1,285 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"net/http"
+	"sync"
+
+	"go.uber.org/zap"
+)
+
+const (
+	SYN_STREAM ControlFrameType = 1 // https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt section 2.6.1
+	SYN_REPLY  ControlFrameType = 2 // https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt section 2.6.2
+	SYN_PING   ControlFrameType = 6 // https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt section 2.6.5
+)
+
+// spdyFrame is a parsed SPDY frame as defined in
+// https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt
+// A SPDY frame can be either a control frame or a data frame.
+type spdyFrame struct {
+	Raw []byte // full frame as raw bytes
+
+	// Common frame fields:
+	Ctrl    bool   // true if this is a SPDY control frame
+	Payload []byte // payload as raw bytes
+
+	// Control frame fields:
+	Version uint16 // SPDY protocol version
+	Type    ControlFrameType
+
+	// Data frame fields:
+	// StreamID is the id of the steam to which this data frame belongs.
+	// SPDY allows transmitting multiple data streams concurrently.
+	StreamID uint32
+}
+
+// Type of an SPDY control frame.
+type ControlFrameType uint16
+
+// Parse parses bytes into spdyFrame.
+// If the bytes don't contain a full frame, return false.
+//
+// Control frame structure:
+//
+//	 +----------------------------------+
+//	|C| Version(15bits) | Type(16bits) |
+//	+----------------------------------+
+//	| Flags (8)  |  Length (24 bits)   |
+//	+----------------------------------+
+//	|               Data               |
+//	+----------------------------------+
+//
+// Data frame structure:
+//
+//	+----------------------------------+
+//	|C|       Stream-ID (31bits)       |
+//	+----------------------------------+
+//	| Flags (8)  |  Length (24 bits)   |
+//	+----------------------------------+
+//	|               Data               |
+//	+----------------------------------+
+//
+// https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt
+func (sf *spdyFrame) Parse(b []byte, log *zap.SugaredLogger) (ok bool, _ error) {
+	const (
+		spdyHeaderLength = 8
+	)
+	have := len(b)
+	if have < spdyHeaderLength { // input does not contain full frame
+		return false, nil
+	}
+
+	if !isSPDYFrameHeader(b) {
+		return false, fmt.Errorf("bytes %v do not seem to contain SPDY frames. Ensure that you are using a SPDY based client to 'kubectl exec'.", b)
+	}
+
+	payloadLength := readInt24(b[5:8])
+	frameLength := payloadLength + spdyHeaderLength
+	if have < frameLength { // input does not contain full frame
+		return false, nil
+	}
+
+	frame := b[:frameLength:frameLength] // enforce frameLength capacity
+
+	sf.Raw = frame
+	sf.Payload = frame[spdyHeaderLength:frameLength]
+
+	sf.Ctrl = hasControlBitSet(frame)
+
+	if !sf.Ctrl { // data frame
+		sf.StreamID = dataFrameStreamID(frame)
+		return true, nil
+	}
+
+	sf.Version = controlFrameVersion(frame)
+	sf.Type = controlFrameType(frame)
+	return true, nil
+}
+
+// parseHeaders retrieves any headers from this spdyFrame.
+func (sf *spdyFrame) parseHeaders(z *zlibReader, log *zap.SugaredLogger) (http.Header, error) {
+	if !sf.Ctrl {
+		return nil, fmt.Errorf("[unexpected] parseHeaders called for a frame that is not a control frame")
+	}
+	const (
+		// +------------------------------------+
+		// |X|           Stream-ID (31bits)     |
+		// +------------------------------------+
+		// |X| Associated-To-Stream-ID (31bits) |
+		// +------------------------------------+
+		// | Pri|Unused | Slot |                |
+		// +-------------------+                |
+		synStreamPayloadLengthBeforeHeaders = 10
+
+		// +------------------------------------+
+		// |X|           Stream-ID (31bits)     |
+		//+------------------------------------+
+		synReplyPayloadLengthBeforeHeaders = 4
+
+		// +----------------------------------|
+		// |            32-bit ID             |
+		// +----------------------------------+
+		pingPayloadLength = 4
+	)
+
+	switch sf.Type {
+	case SYN_STREAM:
+		if len(sf.Payload) < synStreamPayloadLengthBeforeHeaders {
+			return nil, fmt.Errorf("SYN_STREAM frame too short: %v", len(sf.Payload))
+		}
+		z.Set(sf.Payload[synStreamPayloadLengthBeforeHeaders:])
+		return parseHeaders(z, log)
+	case SYN_REPLY:
+		if len(sf.Payload) < synReplyPayloadLengthBeforeHeaders {
+			return nil, fmt.Errorf("SYN_REPLY frame too short: %v", len(sf.Payload))
+		}
+		if len(sf.Payload) == synReplyPayloadLengthBeforeHeaders {
+			return nil, nil // no headers
+		}
+		z.Set(sf.Payload[synReplyPayloadLengthBeforeHeaders:])
+		return parseHeaders(z, log)
+	case SYN_PING:
+		if len(sf.Payload) != pingPayloadLength {
+			return nil, fmt.Errorf("PING frame with unexpected length %v", len(sf.Payload))
+		}
+		return nil, nil // ping frame has no headers
+
+	default:
+		log.Infof("[unexpected] unknown control frame type %v", sf.Type)
+	}
+	return nil, nil
+}
+
+// parseHeaders expects to be passed a reader that contains a compressed SPDY control
+// frame Name/Value Header Block with 0 or more headers:
+//
+// | Number of Name/Value pairs (int32) |   <+
+// +------------------------------------+    |
+// |     Length of name (int32)         |    | This section is the "Name/Value
+// +------------------------------------+    | Header Block", and is compressed.
+// |           Name (string)            |    |
+// +------------------------------------+    |
+// |     Length of value  (int32)       |    |
+// +------------------------------------+    |
+// |          Value   (string)          |    |
+// +------------------------------------+    |
+// |           (repeats)                |   <+
+//
+// It extracts the headers and returns them as http.Header. By doing that it
+// also advances the provided reader past the headers block.
+// See also https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt section 2.6.10
+func parseHeaders(decompressor io.Reader, log *zap.SugaredLogger) (http.Header, error) {
+	buf := bufPool.Get().(*bytes.Buffer)
+	defer bufPool.Put(buf)
+	buf.Reset()
+
+	// readUint32 reads the next 4 decompressed bytes from the decompressor
+	// as a uint32.
+	readUint32 := func() (uint32, error) {
+		const uint32Length = 4
+		if _, err := io.CopyN(buf, decompressor, uint32Length); err != nil { // decompress
+			return 0, fmt.Errorf("error decompressing bytes: %w", err)
+		}
+		return binary.BigEndian.Uint32(buf.Next(uint32Length)), nil // return as uint32
+	}
+
+	// readLenBytes decompresses and returns as bytes the next 'Name' or 'Value'
+	// field from SPDY Name/Value header block. decompressor must be at
+	// 'Length of name'/'Length of value' field.
+	readLenBytes := func() ([]byte, error) {
+		xLen, err := readUint32() // length of field to read
+		if err != nil {
+			return nil, err
+		}
+		if _, err := io.CopyN(buf, decompressor, int64(xLen)); err != nil { // decompress
+			return nil, err
+		}
+		return buf.Next(int(xLen)), nil
+	}
+
+	numHeaders, err := readUint32()
+	if err != nil {
+		return nil, fmt.Errorf("error determining num headers: %v", err)
+	}
+	h := make(http.Header, numHeaders)
+	for i := uint32(0); i < numHeaders; i++ {
+		name, err := readLenBytes()
+		if err != nil {
+			return nil, err
+		}
+		ns := string(name)
+		if _, ok := h[ns]; ok {
+			return nil, fmt.Errorf("invalid data: duplicate header %q", ns)
+		}
+		val, err := readLenBytes()
+		if err != nil {
+			return nil, fmt.Errorf("error reading header data: %w", err)
+		}
+		for _, v := range bytes.Split(val, headerSep) {
+			h.Add(ns, string(v))
+		}
+	}
+	return h, nil
+}
+
+// isSPDYFrame validates that the input bytes start with a valid SPDY frame
+// header.
+func isSPDYFrameHeader(f []byte) bool {
+	if hasControlBitSet(f) {
+		// If this is a control frame, version and type must be set.
+		return controlFrameVersion(f) != uint16(0) && uint16(controlFrameType(f)) != uint16(0)
+	}
+	// If this is a data frame, stream ID must be set.
+	return dataFrameStreamID(f) != uint32(0)
+}
+
+// spdyDataFrameStreamID returns stream ID for an SPDY data frame passed as the
+// input data slice. StreaID is contained within bits [0-31) of a data frame
+// header.
+func dataFrameStreamID(frame []byte) uint32 {
+	return binary.BigEndian.Uint32(frame[0:4]) & 0x7f
+}
+
+// controlFrameType returns the type of a SPDY control frame.
+// See https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt section 2.6
+func controlFrameType(f []byte) ControlFrameType {
+	return ControlFrameType(binary.BigEndian.Uint16(f[2:4]))
+}
+
+// spdyControlFrameVersion returns SPDY version extracted from input bytes that
+// must be a SPDY control frame.
+func controlFrameVersion(frame []byte) uint16 {
+	bs := binary.BigEndian.Uint16(frame[0:2]) // first 16 bits
+	return bs & 0x7f                          // discard control bit
+}
+
+// hasControlBitSet returns true if the passsed bytes have SPDY control bit set.
+// SPDY frames can be either control frames or data frames. A control frame has
+// control bit set to 1 and a data frame has it set to 0.
+func hasControlBitSet(frame []byte) bool {
+	return frame[0]&0x80 == 128 // 0x80
+}
+
+var bufPool = sync.Pool{
+	New: func() any {
+		return new(bytes.Buffer)
+	},
+}
+
+// Headers in SPDY header name/value block are separated by a 0 byte.
+// https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt section 2.6.10
+var headerSep = []byte{0}
+
+func readInt24(b []byte) int {
+	_ = b[2] // bounds check hint to compiler; see golang.org/issue/14808
+	return int(b[0])<<16 | int(b[1])<<8 | int(b[2])
+}

cmd/k8s-operator/spdy-frame_test.go

@@ -0,0 +1,293 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"bytes"
+	"compress/zlib"
+	"encoding/binary"
+	"io"
+	"net/http"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"go.uber.org/zap"
+)
+
+func Test_spdyFrame_Parse(t *testing.T) {
+	zl, err := zap.NewDevelopment()
+	if err != nil {
+		t.Fatal(err)
+	}
+	tests := []struct {
+		name      string
+		gotBytes  []byte
+		wantFrame spdyFrame
+		wantOk    bool
+		wantErr   bool
+	}{
+		{
+			name:     "control_frame_syn_stream",
+			gotBytes: []byte{0x80, 0x3, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0},
+			wantFrame: spdyFrame{
+				Version: 3,
+				Type:    SYN_STREAM,
+				Ctrl:    true,
+				Raw:     []byte{0x80, 0x3, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0},
+				Payload: []byte{},
+			},
+			wantOk: true,
+		},
+		{
+			name:     "control_frame_syn_reply",
+			gotBytes: []byte{0x80, 0x3, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0},
+			wantFrame: spdyFrame{
+				Ctrl:    true,
+				Version: 3,
+				Type:    SYN_REPLY,
+				Raw:     []byte{0x80, 0x3, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0},
+				Payload: []byte{},
+			},
+			wantOk: true,
+		},
+		{
+			name:     "control_frame_headers",
+			gotBytes: []byte{0x80, 0x3, 0x0, 0x8, 0x0, 0x0, 0x0, 0x0},
+			wantFrame: spdyFrame{
+				Ctrl:    true,
+				Version: 3,
+				Type:    8,
+				Raw:     []byte{0x80, 0x3, 0x0, 0x8, 0x0, 0x0, 0x0, 0x0},
+				Payload: []byte{},
+			},
+			wantOk: true,
+		},
+		{
+			name:     "data_frame_stream_id_5",
+			gotBytes: []byte{0x0, 0x0, 0x0, 0x5, 0x0, 0x0, 0x0, 0x0},
+			wantFrame: spdyFrame{
+				Payload:  []byte{},
+				StreamID: 5,
+				Raw:      []byte{0x0, 0x0, 0x0, 0x5, 0x0, 0x0, 0x0, 0x0},
+			},
+			wantOk: true,
+		},
+		{
+			name:     "frame_with_incomplete_header",
+			gotBytes: []byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+		},
+		{
+			name:     "frame_with_incomplete_payload",
+			gotBytes: []byte{0x0, 0x0, 0x0, 0x5, 0x0, 0x0, 0x0, 0x2}, // header specifies payload length of 2
+		},
+		{
+			name:     "control_bit_set_not_spdy_frame",
+			gotBytes: []byte{0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, // header specifies payload length of 2
+			wantErr:  true,
+		},
+		{
+			name:     "control_bit_not_set_not_spdy_frame",
+			gotBytes: []byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, // header specifies payload length of 2
+			wantErr:  true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sf := &spdyFrame{}
+			gotOk, err := sf.Parse(tt.gotBytes, zl.Sugar())
+			if (err != nil) != tt.wantErr {
+				t.Errorf("spdyFrame.Parse() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if gotOk != tt.wantOk {
+				t.Errorf("spdyFrame.Parse() = %v, want %v", gotOk, tt.wantOk)
+			}
+			if diff := cmp.Diff(*sf, tt.wantFrame); diff != "" {
+				t.Errorf("Unexpected SPDY frame (-got +want):\n%s", diff)
+			}
+		})
+	}
+}
+
+func Test_spdyFrame_parseHeaders(t *testing.T) {
+	zl, err := zap.NewDevelopment()
+	if err != nil {
+		t.Fatal(err)
+	}
+	tests := []struct {
+		name       string
+		isCtrl     bool
+		payload    []byte
+		typ        ControlFrameType
+		wantHeader http.Header
+		wantErr    bool
+	}{
+		{
+			name:       "syn_stream_with_header",
+			payload:    payload(t, map[string]string{"Streamtype": "stdin"}, SYN_STREAM, 1),
+			typ:        SYN_STREAM,
+			isCtrl:     true,
+			wantHeader: header(map[string]string{"Streamtype": "stdin"}),
+		},
+		{
+			name:    "syn_ping",
+			payload: payload(t, nil, SYN_PING, 0),
+			typ:     SYN_PING,
+			isCtrl:  true,
+		},
+		{
+			name:       "syn_reply_headers",
+			payload:    payload(t, map[string]string{"foo": "bar", "bar": "baz"}, SYN_REPLY, 0),
+			typ:        SYN_REPLY,
+			isCtrl:     true,
+			wantHeader: header(map[string]string{"foo": "bar", "bar": "baz"}),
+		},
+		{
+			name:    "syn_reply_no_headers",
+			payload: payload(t, nil, SYN_REPLY, 0),
+			typ:     SYN_REPLY,
+			isCtrl:  true,
+		},
+		{
+			name:    "syn_stream_too_short_payload",
+			payload: []byte{0, 1, 2, 3, 4},
+			typ:     SYN_STREAM,
+			isCtrl:  true,
+			wantErr: true,
+		},
+		{
+			name:    "syn_reply_too_short_payload",
+			payload: []byte{0, 1, 2},
+			typ:     SYN_REPLY,
+			isCtrl:  true,
+			wantErr: true,
+		},
+		{
+			name:    "syn_ping_too_short_payload",
+			payload: []byte{0, 1, 2},
+			typ:     SYN_PING,
+			isCtrl:  true,
+			wantErr: true,
+		},
+		{
+			name:    "not_a_control_frame",
+			payload: []byte{0, 1, 2, 3},
+			typ:     SYN_PING,
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		var reader zlibReader
+		t.Run(tt.name, func(t *testing.T) {
+			sf := &spdyFrame{
+				Ctrl:    tt.isCtrl,
+				Type:    tt.typ,
+				Payload: tt.payload,
+			}
+			gotHeader, err := sf.parseHeaders(&reader, zl.Sugar())
+			if (err != nil) != tt.wantErr {
+				t.Errorf("spdyFrame.parseHeaders() error = %v, wantErr %v", err, tt.wantErr)
+			}
+			if !reflect.DeepEqual(gotHeader, tt.wantHeader) {
+				t.Errorf("spdyFrame.parseHeaders() = %v, want %v", gotHeader, tt.wantHeader)
+			}
+		})
+	}
+}
+
+// payload takes a control frame type and a map with 0 or more header keys and
+// values and returns a SPDY control frame payload with the header as SPDY zlib
+// compressed header name/value block. The payload is padded with arbitrary
+// bytes to ensure the header name/value block is in the correct position for
+// the frame type.
+func payload(t *testing.T, headerM map[string]string, typ ControlFrameType, streamID int) []byte {
+	t.Helper()
+
+	buf := bytes.NewBuffer([]byte{})
+	writeControlFramePayloadBeforeHeaders(t, buf, typ, streamID)
+	if len(headerM) == 0 {
+		return buf.Bytes()
+	}
+
+	w, err := zlib.NewWriterLevelDict(buf, zlib.BestCompression, spdyTxtDictionary)
+	if err != nil {
+		t.Fatalf("error creating new zlib writer: %v", err)
+	}
+	if len(headerM) != 0 {
+		writeHeaderValueBlock(t, w, headerM)
+	}
+	if err != nil {
+		t.Fatalf("error writing headers: %v", err)
+	}
+	w.Flush()
+	return buf.Bytes()
+}
+
+// writeControlFramePayloadBeforeHeaders writes to w N bytes, N being the number
+// of bytes that control frame payload for that control frame is required to
+// contain before the name/value header block.
+func writeControlFramePayloadBeforeHeaders(t *testing.T, w io.Writer, typ ControlFrameType, streamID int) {
+	t.Helper()
+	switch typ {
+	case SYN_STREAM:
+		// needs 10 bytes in payload before any headers
+		if err := binary.Write(w, binary.BigEndian, uint32(streamID)); err != nil {
+			t.Fatalf("writing streamID: %v", err)
+		}
+		if err := binary.Write(w, binary.BigEndian, [6]byte{0}); err != nil {
+			t.Fatalf("writing payload: %v", err)
+		}
+	case SYN_REPLY:
+		// needs 4 bytes in payload before any headers
+		if err := binary.Write(w, binary.BigEndian, uint32(0)); err != nil {
+			t.Fatalf("writing payload: %v", err)
+		}
+	case SYN_PING:
+		// needs 4 bytes in payload
+		if err := binary.Write(w, binary.BigEndian, uint32(0)); err != nil {
+			t.Fatalf("writing payload: %v", err)
+		}
+	default:
+		t.Fatalf("unexpected frame type: %v", typ)
+	}
+}
+
+// writeHeaderValue block takes http.Header and zlib writer, writes the headers
+// as SPDY zlib compressed bytes to the writer.
+// Adopted from https://github.com/moby/spdystream/blob/v0.2.0/spdy/write.go#L171-L198 (which is also what Kubernetes uses).
+func writeHeaderValueBlock(t *testing.T, w io.Writer, headerM map[string]string) {
+	t.Helper()
+	h := header(headerM)
+	if err := binary.Write(w, binary.BigEndian, uint32(len(h))); err != nil {
+		t.Fatalf("error writing header block length: %v", err)
+	}
+	for name, values := range h {
+		if err := binary.Write(w, binary.BigEndian, uint32(len(name))); err != nil {
+			t.Fatalf("error writing name length for name %q: %v", name, err)
+		}
+		name = strings.ToLower(name)
+		if _, err := io.WriteString(w, name); err != nil {
+			t.Fatalf("error writing name %q: %v", name, err)
+		}
+		v := strings.Join(values, string(headerSep))
+		if err := binary.Write(w, binary.BigEndian, uint32(len(v))); err != nil {
+			t.Fatalf("error writing value length for value %q: %v", v, err)
+		}
+		if _, err := io.WriteString(w, v); err != nil {
+			t.Fatalf("error writing value %q: %v", v, err)
+		}
+	}
+}
+
+func header(hs map[string]string) http.Header {
+	h := make(http.Header, len(hs))
+	for key, val := range hs {
+		h.Add(key, val)
+	}
+	return h
+}

cmd/k8s-operator/spdy-hijacker.go

@@ -0,0 +1,213 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/netip"
+	"strings"
+
+	"github.com/pkg/errors"
+	"go.uber.org/zap"
+	"tailscale.com/client/tailscale/apitype"
+	"tailscale.com/tailcfg"
+	"tailscale.com/tsnet"
+	"tailscale.com/tstime"
+	"tailscale.com/util/multierr"
+)
+
+// spdyHijacker implements [net/http.Hijacker] interface.
+// It must be configured with an http request for a 'kubectl exec' session that
+// needs to be recorded. It knows how to hijack the connection and configure for
+// the session contents to be sent to a tsrecorder instance.
+type spdyHijacker struct {
+	http.ResponseWriter
+	ts                *tsnet.Server
+	req               *http.Request
+	who               *apitype.WhoIsResponse
+	log               *zap.SugaredLogger
+	pod               string           // pod being exec-d
+	ns                string           // namespace of the pod being exec-d
+	addrs             []netip.AddrPort // tsrecorder addresses
+	failOpen          bool             // whether to fail open if recording fails
+	connectToRecorder RecorderDialFn
+}
+
+// RecorderDialFn dials the specified netip.AddrPorts that should be tsrecorder
+// addresses. It tries to connect to recorder endpoints one by one, till one
+// connection succeeds. In case of success, returns a list with a single
+// successful recording attempt and an error channel. If the connection errors
+// after having been established, an error is sent down the channel.
+type RecorderDialFn func(context.Context, []netip.AddrPort, func(context.Context, string, string) (net.Conn, error)) (io.WriteCloser, []*tailcfg.SSHRecordingAttempt, <-chan error, error)
+
+// Hijack hijacks a 'kubectl exec' session and configures for the session
+// contents to be sent to a recorder.
+func (h *spdyHijacker) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	h.log.Infof("recorder addrs: %v, failOpen: %v", h.addrs, h.failOpen)
+	reqConn, brw, err := h.ResponseWriter.(http.Hijacker).Hijack()
+	if err != nil {
+		return nil, nil, fmt.Errorf("error hijacking connection: %w", err)
+	}
+
+	conn, err := h.setUpRecording(context.Background(), reqConn)
+	if err != nil {
+		return nil, nil, fmt.Errorf("error setting up session recording: %w", err)
+	}
+	return conn, brw, nil
+}
+
+// setupRecording attempts to connect to the recorders set via
+// spdyHijacker.addrs. Returns conn from provided opts, wrapped in recording
+// logic. If connecting to the recorder fails or an error is received during the
+// session and spdyHijacker.failOpen is false, connection will be closed.
+func (h *spdyHijacker) setUpRecording(ctx context.Context, conn net.Conn) (net.Conn, error) {
+	const (
+		// https://docs.asciinema.org/manual/asciicast/v2/
+		asciicastv2 = 2
+	)
+	var wc io.WriteCloser
+	h.log.Infof("kubectl exec session will be recorded, recorders: %v, fail open policy: %t", h.addrs, h.failOpen)
+	// TODO (irbekrm): send client a message that session will be recorded.
+	rw, _, errChan, err := h.connectToRecorder(ctx, h.addrs, h.ts.Dial)
+	if err != nil {
+		msg := fmt.Sprintf("error connecting to session recorders: %v", err)
+		if h.failOpen {
+			msg = msg + "; failure mode is 'fail open'; continuing session without recording."
+			h.log.Warnf(msg)
+			return conn, nil
+		}
+		msg = msg + "; failure mode is 'fail closed'; closing connection."
+		if err := closeConnWithWarning(conn, msg); err != nil {
+			return nil, multierr.New(errors.New(msg), err)
+		}
+		return nil, errors.New(msg)
+	}
+
+	// TODO (irbekrm): log which recorder
+	h.log.Info("successfully connected to a session recorder")
+	wc = rw
+	cl := tstime.DefaultClock{}
+	lc := &spdyRemoteConnRecorder{
+		log:  h.log,
+		Conn: conn,
+		rec: &recorder{
+			start:    cl.Now(),
+			clock:    cl,
+			failOpen: h.failOpen,
+			conn:     wc,
+		},
+	}
+
+	qp := h.req.URL.Query()
+	ch := CastHeader{
+		Version:   asciicastv2,
+		Timestamp: lc.rec.start.Unix(),
+		Command:   strings.Join(qp["command"], " "),
+		SrcNode:   strings.TrimSuffix(h.who.Node.Name, "."),
+		SrcNodeID: h.who.Node.StableID,
+		Kubernetes: &Kubernetes{
+			PodName:   h.pod,
+			Namespace: h.ns,
+			Container: strings.Join(qp["container"], " "),
+		},
+	}
+	if !h.who.Node.IsTagged() {
+		ch.SrcNodeUser = h.who.UserProfile.LoginName
+		ch.SrcNodeUserID = h.who.Node.User
+	} else {
+		ch.SrcNodeTags = h.who.Node.Tags
+	}
+	lc.ch = ch
+	go func() {
+		var err error
+		select {
+		case <-ctx.Done():
+			return
+		case err = <-errChan:
+		}
+		if err == nil {
+			counterSessionRecordingsUploaded.Add(1)
+			h.log.Info("finished uploading the recording")
+			return
+		}
+		msg := fmt.Sprintf("connection to the session recorder errorred: %v;", err)
+		if h.failOpen {
+			msg += msg + "; failure mode is 'fail open'; continuing session without recording."
+			h.log.Info(msg)
+			return
+		}
+		msg += "; failure mode set to 'fail closed'; closing connection"
+		h.log.Error(msg)
+		lc.failed = true
+		// TODO (irbekrm): write a message to the client
+		if err := lc.Close(); err != nil {
+			h.log.Infof("error closing recorder connections: %v", err)
+		}
+		return
+	}()
+	return lc, nil
+}
+
+// CastHeader is the asciicast header to be sent to the recorder at the start of
+// the recording of a session.
+// https://docs.asciinema.org/manual/asciicast/v2/#header
+type CastHeader struct {
+	// Version is the asciinema file format version.
+	Version int `json:"version"`
+
+	// Width is the terminal width in characters.
+	Width int `json:"width"`
+
+	// Height is the terminal height in characters.
+	Height int `json:"height"`
+
+	// Timestamp is the unix timestamp of when the recording started.
+	Timestamp int64 `json:"timestamp"`
+
+	// Tailscale-specific fields: SrcNode is the full MagicDNS name of the
+	// tailnet node originating the connection, without the trailing dot.
+	SrcNode string `json:"srcNode"`
+
+	// SrcNodeID is the node ID of the tailnet node originating the connection.
+	SrcNodeID tailcfg.StableNodeID `json:"srcNodeID"`
+
+	// SrcNodeTags is the list of tags on the node originating the connection (if any).
+	SrcNodeTags []string `json:"srcNodeTags,omitempty"`
+
+	// SrcNodeUserID is the user ID of the node originating the connection (if not tagged).
+	SrcNodeUserID tailcfg.UserID `json:"srcNodeUserID,omitempty"` // if not tagged
+
+	// SrcNodeUser is the LoginName of the node originating the connection (if not tagged).
+	SrcNodeUser string `json:"srcNodeUser,omitempty"`
+
+	Command string
+
+	// Kubernetes-specific fields:
+	Kubernetes *Kubernetes `json:"kubernetes,omitempty"`
+}
+
+// Kubernetes contains 'kubectl exec' session specific information for
+// tsrecorder.
+type Kubernetes struct {
+	PodName   string
+	Namespace string
+	Container string
+}
+
+func closeConnWithWarning(conn net.Conn, msg string) error {
+	b := io.NopCloser(bytes.NewBuffer([]byte(msg)))
+	resp := http.Response{Status: http.StatusText(http.StatusForbidden), StatusCode: http.StatusForbidden, Body: b}
+	if err := resp.Write(conn); err != nil {
+		return multierr.New(fmt.Errorf("error writing msg %q to conn: %v", msg, err), conn.Close())
+	}
+	return conn.Close()
+}

cmd/k8s-operator/spdy-hijacker_test.go

@@ -0,0 +1,111 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/netip"
+	"net/url"
+	"testing"
+	"time"
+
+	"go.uber.org/zap"
+	"tailscale.com/client/tailscale/apitype"
+	"tailscale.com/tailcfg"
+	"tailscale.com/tsnet"
+	"tailscale.com/tstest"
+)
+
+func Test_SPDYHijacker(t *testing.T) {
+	zl, err := zap.NewDevelopment()
+	if err != nil {
+		t.Fatal(err)
+	}
+	tests := []struct {
+		name                        string
+		failOpen                    bool
+		failRecorderConnect         bool // fail initial connect to the recorder
+		failRecorderConnPostConnect bool // send error down the error channel
+		wantsConnClosed             bool
+		wantsSetupErr               bool
+	}{
+		{
+			name: "setup succeeds, conn stays open",
+		},
+		{
+			name:                "setup fails, policy is to fail open, conn stays open",
+			failOpen:            true,
+			failRecorderConnect: true,
+		},
+		{
+			name:                "setup fails, policy is to fail closed, conn is closed",
+			failRecorderConnect: true,
+			wantsSetupErr:       true,
+			wantsConnClosed:     true,
+		},
+		{
+			name:                        "connection fails post-initial connect, policy is to fail open, conn stays open",
+			failRecorderConnPostConnect: true,
+			failOpen:                    true,
+		},
+		{
+			name:                        "connection fails post-initial connect, policy is to fail closed, conn is closed",
+			failRecorderConnPostConnect: true,
+			wantsConnClosed:             true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tc := &testConn{}
+			ch := make(chan error)
+			h := &spdyHijacker{
+				connectToRecorder: func(context.Context, []netip.AddrPort, func(context.Context, string, string) (net.Conn, error)) (wc io.WriteCloser, rec []*tailcfg.SSHRecordingAttempt, _ <-chan error, err error) {
+					if tt.failRecorderConnect {
+						err = errors.New("test")
+					}
+					return wc, rec, ch, err
+				},
+				failOpen: tt.failOpen,
+				who:      &apitype.WhoIsResponse{Node: &tailcfg.Node{}, UserProfile: &tailcfg.UserProfile{}},
+				log:      zl.Sugar(),
+				ts:       &tsnet.Server{},
+				req:      &http.Request{URL: &url.URL{}},
+			}
+			ctx := context.Background()
+			_, err := h.setUpRecording(ctx, tc)
+			if (err != nil) != tt.wantsSetupErr {
+				t.Errorf("spdyHijacker.setupRecording() error = %v, wantErr %v", err, tt.wantsSetupErr)
+				return
+			}
+			if tt.failRecorderConnPostConnect {
+				select {
+				case ch <- errors.New("err"):
+				case <-time.After(time.Second * 15):
+					t.Errorf("error from recorder conn was not read within 15 seconds")
+				}
+			}
+			timeout := time.Second * 20
+			// TODO (irbekrm): cover case where an error is received
+			// over channel and the failure policy is to fail open
+			// (test that connection remains open over some period
+			// of time).
+			if err := tstest.WaitFor(timeout, func() (err error) {
+				if tt.wantsConnClosed != tc.isClosed() {
+					return fmt.Errorf("got connection state: %t, wants connection state: %t", tc.isClosed(), tt.wantsConnClosed)
+				}
+				return nil
+			}); err != nil {
+				t.Errorf("connection did not reach the desired state within %s", timeout.String())
+			}
+			ctx.Done()
+		})
+	}
+}

cmd/k8s-operator/spdy-remote-conn-recorder.go

@@ -0,0 +1,194 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+	"sync"
+	"sync/atomic"
+
+	"go.uber.org/zap"
+	corev1 "k8s.io/api/core/v1"
+)
+
+// spdyRemoteConnRecorder is a wrapper around net.Conn. It reads the bytestream
+// for a 'kubectl exec' session, sends session recording data to the configured
+// recorder and forwards the raw bytes to the original destination.
+type spdyRemoteConnRecorder struct {
+	net.Conn
+	// rec knows how to send data written to it to a tsrecorder instance.
+	rec *recorder
+	ch  CastHeader
+
+	stdoutStreamID atomic.Uint32
+	stderrStreamID atomic.Uint32
+	resizeStreamID atomic.Uint32
+
+	wmu    sync.Mutex // sequences writes
+	closed bool
+	failed bool
+
+	rmu                 sync.Mutex // sequences reads
+	writeCastHeaderOnce sync.Once
+
+	zlibReqReader zlibReader
+	// writeBuf is used to store data written to the connection that has not
+	// yet been parsed as SPDY frames.
+	writeBuf bytes.Buffer
+	// readBuf is used to store data read from the connection that has not
+	// yet been parsed as SPDY frames.
+	readBuf bytes.Buffer
+	log     *zap.SugaredLogger
+}
+
+// Read reads bytes from the original connection and parses them as SPDY frames.
+// If the frame is a data frame for resize stream, sends resize message to the
+// recorder. If the frame is a SYN_STREAM control frame that starts stdout,
+// stderr or resize stream, store the stream ID.
+func (c *spdyRemoteConnRecorder) Read(b []byte) (int, error) {
+	c.rmu.Lock()
+	defer c.rmu.Unlock()
+	n, err := c.Conn.Read(b)
+	if err != nil {
+		return n, fmt.Errorf("error reading from connection: %w", err)
+	}
+	c.readBuf.Write(b[:n])
+
+	var sf spdyFrame
+	ok, err := sf.Parse(c.readBuf.Bytes(), c.log)
+	if err != nil {
+		return 0, fmt.Errorf("error parsing data read from connection: %w", err)
+	}
+	if !ok {
+		// The parsed data in the buffer will be processed together with
+		// the new data on the next call to Read.
+		return n, nil
+	}
+	c.readBuf.Next(len(sf.Raw)) // advance buffer past the parsed frame
+
+	if !sf.Ctrl { // data frame
+		switch sf.StreamID {
+		case c.resizeStreamID.Load():
+			var err error
+			var msg spdyResizeMsg
+			if err = json.Unmarshal(sf.Payload, &msg); err != nil {
+				return 0, fmt.Errorf("error umarshalling resize msg: %w", err)
+			}
+			c.ch.Width = msg.Width
+			c.ch.Height = msg.Height
+		}
+		return n, nil
+	}
+	// We always want to parse the headers, even if we don't care about the
+	// frame, as we need to advance the zlib reader otherwise we will get
+	// garbage.
+	header, err := sf.parseHeaders(&c.zlibReqReader, c.log)
+	if err != nil {
+		return 0, fmt.Errorf("error parsing frame headers: %w", err)
+	}
+	if sf.Type == SYN_STREAM {
+		c.storeStreamID(sf, header)
+	}
+	return n, nil
+}
+
+// Write forwards the raw data of the latest parsed SPDY frame to the original
+// destination. If the frame is an SPDY data frame, it also sends the payload to
+// the connected session recorder.
+func (c *spdyRemoteConnRecorder) Write(b []byte) (int, error) {
+	c.wmu.Lock()
+	defer c.wmu.Unlock()
+	c.writeBuf.Write(b)
+
+	var sf spdyFrame
+	ok, err := sf.Parse(c.writeBuf.Bytes(), c.log)
+	if err != nil {
+		return 0, fmt.Errorf("error parsing data: %w", err)
+	}
+	if !ok {
+		// The parsed data in the buffer will be processed together with
+		// the new data on the next call to Write.
+		return len(b), nil
+	}
+	c.writeBuf.Next(len(sf.Raw)) // advance buffer past the parsed frame
+
+	// If this is a stdout or stderr data frame, send its payload to the
+	// session recorder.
+	if !sf.Ctrl {
+		switch sf.StreamID {
+		case c.stdoutStreamID.Load(), c.stderrStreamID.Load():
+			var err error
+			c.writeCastHeaderOnce.Do(func() {
+				var j []byte
+				j, err = json.Marshal(c.ch)
+				if err != nil {
+					return
+				}
+				j = append(j, '\n')
+				err = c.rec.writeCastLine(j)
+				if err != nil {
+					c.log.Errorf("received error from recorder: %v", err)
+				}
+			})
+			if err != nil {
+				return 0, fmt.Errorf("error writing CastHeader: %w", err)
+			}
+			if err := c.rec.Write(sf.Payload); err != nil {
+				return 0, fmt.Errorf("error sending payload to session recorder: %w", err)
+			}
+		}
+	}
+	// Forward the whole frame to the original destination.
+	_, err = c.Conn.Write(sf.Raw) // send to net.Conn
+	return len(b), err
+}
+
+func (c *spdyRemoteConnRecorder) Close() error {
+	c.wmu.Lock()
+	defer c.wmu.Unlock()
+	if c.closed {
+		return nil
+	}
+	if !c.failed && c.writeBuf.Len() > 0 {
+		c.Conn.Write(c.writeBuf.Bytes())
+	}
+	c.writeBuf.Reset()
+	c.closed = true
+	err := c.Conn.Close()
+	c.rec.Close()
+	return err
+}
+
+// parseSynStream parses SYN_STREAM SPDY control frame and updates
+// spdyRemoteConnRecorder to store the newly created stream's ID if it is one of
+// the stream types we care about. Storing stream_id:stream_type mapping allows
+// us to parse received data frames (that have stream IDs) differently depening
+// on which stream they belong to (i.e send data frame payload for stdout stream
+// to session recorder).
+func (c *spdyRemoteConnRecorder) storeStreamID(sf spdyFrame, header http.Header) {
+	const (
+		streamTypeHeaderKey = "Streamtype"
+	)
+	id := binary.BigEndian.Uint32(sf.Payload[0:4])
+	switch header.Get(streamTypeHeaderKey) {
+	case corev1.StreamTypeStdout:
+		c.stdoutStreamID.Store(id)
+	case corev1.StreamTypeStderr:
+		c.stderrStreamID.Store(id)
+	case corev1.StreamTypeResize:
+		c.resizeStreamID.Store(id)
+	}
+}
+
+type spdyResizeMsg struct {
+	Width  int `json:"width"`
+	Height int `json:"height"`
+}

cmd/k8s-operator/spdy-remote-conn-recorder_test.go

@@ -0,0 +1,326 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"net"
+	"reflect"
+	"sync"
+	"testing"
+
+	"go.uber.org/zap"
+	"tailscale.com/tstest"
+	"tailscale.com/tstime"
+)
+
+// Test_Writes tests that 1 or more Write calls to spdyRemoteConnRecorder
+// results in the expected data being forwarded to the original destination and
+// the session recorder.
+func Test_Writes(t *testing.T) {
+	var stdoutStreamID, stderrStreamID uint32 = 1, 2
+	zl, err := zap.NewDevelopment()
+	if err != nil {
+		t.Fatal(err)
+	}
+	cl := tstest.NewClock(tstest.ClockOpts{})
+	tests := []struct {
+		name          string
+		inputs        [][]byte
+		wantForwarded []byte
+		wantRecorded  []byte
+		firstWrite    bool
+		width         int
+		height        int
+	}{
+		{
+			name:          "single_write_control_frame_with_payload",
+			inputs:        [][]byte{{0x80, 0x3, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1, 0x5}},
+			wantForwarded: []byte{0x80, 0x3, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1, 0x5},
+		},
+		{
+			name:          "two_writes_control_frame_with_leftover",
+			inputs:        [][]byte{{0x80, 0x3, 0x0, 0x1}, {0x0, 0x0, 0x0, 0x1, 0x5, 0x80, 0x3}},
+			wantForwarded: []byte{0x80, 0x3, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1, 0x5},
+		},
+		{
+			name:          "single_write_stdout_data_frame",
+			inputs:        [][]byte{{0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0}},
+			wantForwarded: []byte{0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0},
+		},
+		{
+			name:          "single_write_stdout_data_frame_with_payload",
+			inputs:        [][]byte{{0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5}},
+			wantForwarded: []byte{0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5},
+			wantRecorded:  castLine(t, []byte{0x1, 0x2, 0x3, 0x4, 0x5}, cl),
+		},
+		{
+			name:          "single_write_stderr_data_frame_with_payload",
+			inputs:        [][]byte{{0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5}},
+			wantForwarded: []byte{0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5},
+			wantRecorded:  castLine(t, []byte{0x1, 0x2, 0x3, 0x4, 0x5}, cl),
+		},
+		{
+			name:          "single_data_frame_unknow_stream_with_payload",
+			inputs:        [][]byte{{0x0, 0x0, 0x0, 0x7, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5}},
+			wantForwarded: []byte{0x0, 0x0, 0x0, 0x7, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5},
+		},
+		{
+			name:          "control_frame_and_data_frame_split_across_two_writes",
+			inputs:        [][]byte{{0x80, 0x3, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1}, {0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5}},
+			wantForwarded: []byte{0x80, 0x3, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5},
+			wantRecorded:  castLine(t, []byte{0x1, 0x2, 0x3, 0x4, 0x5}, cl),
+		},
+		{
+			name:          "single_first_write_stdout_data_frame_with_payload",
+			inputs:        [][]byte{{0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5}},
+			wantForwarded: []byte{0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x5, 0x1, 0x2, 0x3, 0x4, 0x5},
+			wantRecorded:  append(asciinemaResizeMsg(t, 10, 20), castLine(t, []byte{0x1, 0x2, 0x3, 0x4, 0x5}, cl)...),
+			width:         10,
+			height:        20,
+			firstWrite:    true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tc := &testConn{}
+			sr := &testSessionRecorder{}
+			rec := &recorder{
+				conn:  sr,
+				clock: cl,
+				start: cl.Now(),
+			}
+
+			c := &spdyRemoteConnRecorder{
+				Conn: tc,
+				log:  zl.Sugar(),
+				rec:  rec,
+				ch: CastHeader{
+					Width:  tt.width,
+					Height: tt.height,
+				},
+			}
+			if !tt.firstWrite {
+				// this test case does not intend to test that cast header gets written once
+				c.writeCastHeaderOnce.Do(func() {})
+			}
+
+			c.stdoutStreamID.Store(stdoutStreamID)
+			c.stderrStreamID.Store(stderrStreamID)
+			for i, input := range tt.inputs {
+				if _, err := c.Write(input); err != nil {
+					t.Errorf("[%d] spdyRemoteConnRecorder.Write() unexpected error %v", i, err)
+				}
+			}
+
+			// Assert that the expected bytes have been forwarded to the original destination.
+			gotForwarded := tc.writeBuf.Bytes()
+			if !reflect.DeepEqual(gotForwarded, tt.wantForwarded) {
+				t.Errorf("expected bytes not forwarded, wants\n%v\ngot\n%v", tt.wantForwarded, gotForwarded)
+			}
+
+			// Assert that the expected bytes have been forwarded to the session recorder.
+			gotRecorded := sr.buf.Bytes()
+			if !reflect.DeepEqual(gotRecorded, tt.wantRecorded) {
+				t.Errorf("expected bytes not recorded, wants\n%v\ngot\n%v", tt.wantRecorded, gotRecorded)
+			}
+		})
+	}
+}
+
+// Test_Reads tests that 1 or more Read calls to spdyRemoteConnRecorder results
+// in the expected data being forwarded to the original destination and the
+// session recorder.
+func Test_Reads(t *testing.T) {
+	zl, err := zap.NewDevelopment()
+	if err != nil {
+		t.Fatal(err)
+	}
+	cl := tstest.NewClock(tstest.ClockOpts{})
+	var reader zlibReader
+	resizeMsg := resizeMsgBytes(t, 10, 20)
+	synStreamStdoutPayload := payload(t, map[string]string{"Streamtype": "stdout"}, SYN_STREAM, 1)
+	synStreamStderrPayload := payload(t, map[string]string{"Streamtype": "stderr"}, SYN_STREAM, 2)
+	synStreamResizePayload := payload(t, map[string]string{"Streamtype": "resize"}, SYN_STREAM, 3)
+	syn_stream_ctrl_header := []byte{0x80, 0x3, 0x0, 0x1, 0x0, 0x0, 0x0, uint8(len(synStreamStdoutPayload))}
+
+	tests := []struct {
+		name                     string
+		inputs                   [][]byte
+		wantStdoutStreamID       uint32
+		wantStderrStreamID       uint32
+		wantResizeStreamID       uint32
+		wantWidth                int
+		wantHeight               int
+		resizeStreamIDBeforeRead uint32
+	}{
+		{
+			name:                     "resize_data_frame_single_read",
+			inputs:                   [][]byte{append([]byte{0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, uint8(len(resizeMsg))}, resizeMsg...)},
+			resizeStreamIDBeforeRead: 1,
+			wantWidth:                10,
+			wantHeight:               20,
+		},
+		{
+			name:                     "resize_data_frame_two_reads",
+			inputs:                   [][]byte{{0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, uint8(len(resizeMsg))}, resizeMsg},
+			resizeStreamIDBeforeRead: 1,
+			wantWidth:                10,
+			wantHeight:               20,
+		},
+		{
+			name:               "syn_stream_ctrl_frame_stdout_single_read",
+			inputs:             [][]byte{append(syn_stream_ctrl_header, synStreamStdoutPayload...)},
+			wantStdoutStreamID: 1,
+		},
+		{
+			name:               "syn_stream_ctrl_frame_stderr_single_read",
+			inputs:             [][]byte{append(syn_stream_ctrl_header, synStreamStderrPayload...)},
+			wantStderrStreamID: 2,
+		},
+		{
+			name:               "syn_stream_ctrl_frame_resize_single_read",
+			inputs:             [][]byte{append(syn_stream_ctrl_header, synStreamResizePayload...)},
+			wantResizeStreamID: 3,
+		},
+		{
+			name:               "syn_stream_ctrl_frame_resize_four_reads_with_leftover",
+			inputs:             [][]byte{syn_stream_ctrl_header, append(synStreamResizePayload, syn_stream_ctrl_header...), append(synStreamStderrPayload, syn_stream_ctrl_header...), append(synStreamStdoutPayload, 0x0, 0x3)},
+			wantStdoutStreamID: 1,
+			wantStderrStreamID: 2,
+			wantResizeStreamID: 3,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tc := &testConn{}
+			sr := &testSessionRecorder{}
+			rec := &recorder{
+				conn:  sr,
+				clock: cl,
+				start: cl.Now(),
+			}
+			c := &spdyRemoteConnRecorder{
+				Conn: tc,
+				log:  zl.Sugar(),
+				rec:  rec,
+			}
+			c.resizeStreamID.Store(tt.resizeStreamIDBeforeRead)
+
+			for i, input := range tt.inputs {
+				c.zlibReqReader = reader
+				tc.readBuf.Reset()
+				_, err := tc.readBuf.Write(input)
+				if err != nil {
+					t.Fatalf("writing bytes to test conn: %v", err)
+				}
+				_, err = c.Read(make([]byte, len(input)))
+				if err != nil {
+					t.Errorf("[%d] spdyRemoteConnRecorder.Read() resulted in an unexpected error: %v", i, err)
+				}
+			}
+			if id := c.resizeStreamID.Load(); id != tt.wantResizeStreamID && id != tt.resizeStreamIDBeforeRead {
+				t.Errorf("wants resizeStreamID: %d, got %d", tt.wantResizeStreamID, id)
+			}
+			if id := c.stderrStreamID.Load(); id != tt.wantStderrStreamID {
+				t.Errorf("wants stderrStreamID: %d, got %d", tt.wantStderrStreamID, id)
+			}
+			if id := c.stdoutStreamID.Load(); id != tt.wantStdoutStreamID {
+				t.Errorf("wants stdoutStreamID: %d, got %d", tt.wantStdoutStreamID, id)
+			}
+			if tt.wantHeight != 0 || tt.wantWidth != 0 {
+				if tt.wantWidth != c.ch.Width {
+					t.Errorf("wants width: %v, got %v", tt.wantWidth, c.ch.Width)
+				}
+				if tt.wantHeight != c.ch.Height {
+					t.Errorf("want height: %v, got %v", tt.wantHeight, c.ch.Height)
+				}
+			}
+		})
+	}
+}
+
+func castLine(t *testing.T, p []byte, clock tstime.Clock) []byte {
+	t.Helper()
+	j, err := json.Marshal([]any{
+		clock.Now().Sub(clock.Now()).Seconds(),
+		"o",
+		string(p),
+	})
+	if err != nil {
+		t.Fatalf("error marshalling cast line: %v", err)
+	}
+	return append(j, '\n')
+}
+
+func resizeMsgBytes(t *testing.T, width, height int) []byte {
+	t.Helper()
+	bs, err := json.Marshal(spdyResizeMsg{Width: width, Height: height})
+	if err != nil {
+		t.Fatalf("error marshalling resizeMsg: %v", err)
+	}
+	return bs
+}
+
+func asciinemaResizeMsg(t *testing.T, width, height int) []byte {
+	t.Helper()
+	ch := CastHeader{
+		Width:  width,
+		Height: height,
+	}
+	bs, err := json.Marshal(ch)
+	if err != nil {
+		t.Fatalf("error marshalling CastHeader: %v", err)
+	}
+	return append(bs, '\n')
+}
+
+type testConn struct {
+	net.Conn
+	// writeBuf contains whatever was send to the conn via Write.
+	writeBuf bytes.Buffer
+	// readBuf contains whatever was sent to the conn via Read.
+	readBuf      bytes.Buffer
+	sync.RWMutex // protects the following
+	closed       bool
+}
+
+var _ net.Conn = &testConn{}
+
+func (tc *testConn) Read(b []byte) (int, error) {
+	return tc.readBuf.Read(b)
+}
+
+func (tc *testConn) Write(b []byte) (int, error) {
+	return tc.writeBuf.Write(b)
+}
+
+func (tc *testConn) Close() error {
+	tc.Lock()
+	defer tc.Unlock()
+	tc.closed = true
+	return nil
+}
+func (tc *testConn) isClosed() bool {
+	tc.Lock()
+	defer tc.Unlock()
+	return tc.closed
+}
+
+type testSessionRecorder struct {
+	// buf holds data that was sent to the session recorder.
+	buf bytes.Buffer
+}
+
+func (t *testSessionRecorder) Write(b []byte) (int, error) {
+	return t.buf.Write(b)
+}
+
+func (t *testSessionRecorder) Close() error {
+	t.buf.Reset()
+	return nil
+}

cmd/k8s-operator/zlib-reader.go

@@ -0,0 +1,221 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"bytes"
+	"compress/zlib"
+	"io"
+)
+
+// zlibReader contains functionality to parse zlib compressed SPDY data.
+// See https://www.ietf.org/archive/id/draft-mbelshe-httpbis-spdy-00.txt section 2.6.10.1
+type zlibReader struct {
+	io.ReadCloser
+	underlying io.LimitedReader // zlib compressed SPDY data
+}
+
+// Read decompresses zlibReader's underlying zlib compressed SPDY data and reads
+// it into b.
+func (z *zlibReader) Read(b []byte) (int, error) {
+	if z.ReadCloser == nil {
+		r, err := zlib.NewReaderDict(&z.underlying, spdyTxtDictionary)
+		if err != nil {
+			return 0, err
+		}
+		z.ReadCloser = r
+	}
+	return z.ReadCloser.Read(b)
+}
+
+// Set sets zlibReader's underlying data. b must be zlib compressed SPDY data.
+func (z *zlibReader) Set(b []byte) {
+	z.underlying.R = bytes.NewReader(b)
+	z.underlying.N = int64(len(b))
+}
+
+// spdyTxtDictionary is the dictionary defined in the SPDY spec.
+// https://datatracker.ietf.org/doc/html/draft-mbelshe-httpbis-spdy-00#section-2.6.10.1
+var spdyTxtDictionary = []byte{
+	0x00, 0x00, 0x00, 0x07, 0x6f, 0x70, 0x74, 0x69, // - - - - o p t i
+	0x6f, 0x6e, 0x73, 0x00, 0x00, 0x00, 0x04, 0x68, // o n s - - - - h
+	0x65, 0x61, 0x64, 0x00, 0x00, 0x00, 0x04, 0x70, // e a d - - - - p
+	0x6f, 0x73, 0x74, 0x00, 0x00, 0x00, 0x03, 0x70, // o s t - - - - p
+	0x75, 0x74, 0x00, 0x00, 0x00, 0x06, 0x64, 0x65, // u t - - - - d e
+	0x6c, 0x65, 0x74, 0x65, 0x00, 0x00, 0x00, 0x05, // l e t e - - - -
+	0x74, 0x72, 0x61, 0x63, 0x65, 0x00, 0x00, 0x00, // t r a c e - - -
+	0x06, 0x61, 0x63, 0x63, 0x65, 0x70, 0x74, 0x00, // - a c c e p t -
+	0x00, 0x00, 0x0e, 0x61, 0x63, 0x63, 0x65, 0x70, // - - - a c c e p
+	0x74, 0x2d, 0x63, 0x68, 0x61, 0x72, 0x73, 0x65, // t - c h a r s e
+	0x74, 0x00, 0x00, 0x00, 0x0f, 0x61, 0x63, 0x63, // t - - - - a c c
+	0x65, 0x70, 0x74, 0x2d, 0x65, 0x6e, 0x63, 0x6f, // e p t - e n c o
+	0x64, 0x69, 0x6e, 0x67, 0x00, 0x00, 0x00, 0x0f, // d i n g - - - -
+	0x61, 0x63, 0x63, 0x65, 0x70, 0x74, 0x2d, 0x6c, // a c c e p t - l
+	0x61, 0x6e, 0x67, 0x75, 0x61, 0x67, 0x65, 0x00, // a n g u a g e -
+	0x00, 0x00, 0x0d, 0x61, 0x63, 0x63, 0x65, 0x70, // - - - a c c e p
+	0x74, 0x2d, 0x72, 0x61, 0x6e, 0x67, 0x65, 0x73, // t - r a n g e s
+	0x00, 0x00, 0x00, 0x03, 0x61, 0x67, 0x65, 0x00, // - - - - a g e -
+	0x00, 0x00, 0x05, 0x61, 0x6c, 0x6c, 0x6f, 0x77, // - - - a l l o w
+	0x00, 0x00, 0x00, 0x0d, 0x61, 0x75, 0x74, 0x68, // - - - - a u t h
+	0x6f, 0x72, 0x69, 0x7a, 0x61, 0x74, 0x69, 0x6f, // o r i z a t i o
+	0x6e, 0x00, 0x00, 0x00, 0x0d, 0x63, 0x61, 0x63, // n - - - - c a c
+	0x68, 0x65, 0x2d, 0x63, 0x6f, 0x6e, 0x74, 0x72, // h e - c o n t r
+	0x6f, 0x6c, 0x00, 0x00, 0x00, 0x0a, 0x63, 0x6f, // o l - - - - c o
+	0x6e, 0x6e, 0x65, 0x63, 0x74, 0x69, 0x6f, 0x6e, // n n e c t i o n
+	0x00, 0x00, 0x00, 0x0c, 0x63, 0x6f, 0x6e, 0x74, // - - - - c o n t
+	0x65, 0x6e, 0x74, 0x2d, 0x62, 0x61, 0x73, 0x65, // e n t - b a s e
+	0x00, 0x00, 0x00, 0x10, 0x63, 0x6f, 0x6e, 0x74, // - - - - c o n t
+	0x65, 0x6e, 0x74, 0x2d, 0x65, 0x6e, 0x63, 0x6f, // e n t - e n c o
+	0x64, 0x69, 0x6e, 0x67, 0x00, 0x00, 0x00, 0x10, // d i n g - - - -
+	0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e, 0x74, 0x2d, // c o n t e n t -
+	0x6c, 0x61, 0x6e, 0x67, 0x75, 0x61, 0x67, 0x65, // l a n g u a g e
+	0x00, 0x00, 0x00, 0x0e, 0x63, 0x6f, 0x6e, 0x74, // - - - - c o n t
+	0x65, 0x6e, 0x74, 0x2d, 0x6c, 0x65, 0x6e, 0x67, // e n t - l e n g
+	0x74, 0x68, 0x00, 0x00, 0x00, 0x10, 0x63, 0x6f, // t h - - - - c o
+	0x6e, 0x74, 0x65, 0x6e, 0x74, 0x2d, 0x6c, 0x6f, // n t e n t - l o
+	0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x00, 0x00, // c a t i o n - -
+	0x00, 0x0b, 0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e, // - - c o n t e n
+	0x74, 0x2d, 0x6d, 0x64, 0x35, 0x00, 0x00, 0x00, // t - m d 5 - - -
+	0x0d, 0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e, 0x74, // - c o n t e n t
+	0x2d, 0x72, 0x61, 0x6e, 0x67, 0x65, 0x00, 0x00, // - r a n g e - -
+	0x00, 0x0c, 0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e, // - - c o n t e n
+	0x74, 0x2d, 0x74, 0x79, 0x70, 0x65, 0x00, 0x00, // t - t y p e - -
+	0x00, 0x04, 0x64, 0x61, 0x74, 0x65, 0x00, 0x00, // - - d a t e - -
+	0x00, 0x04, 0x65, 0x74, 0x61, 0x67, 0x00, 0x00, // - - e t a g - -
+	0x00, 0x06, 0x65, 0x78, 0x70, 0x65, 0x63, 0x74, // - - e x p e c t
+	0x00, 0x00, 0x00, 0x07, 0x65, 0x78, 0x70, 0x69, // - - - - e x p i
+	0x72, 0x65, 0x73, 0x00, 0x00, 0x00, 0x04, 0x66, // r e s - - - - f
+	0x72, 0x6f, 0x6d, 0x00, 0x00, 0x00, 0x04, 0x68, // r o m - - - - h
+	0x6f, 0x73, 0x74, 0x00, 0x00, 0x00, 0x08, 0x69, // o s t - - - - i
+	0x66, 0x2d, 0x6d, 0x61, 0x74, 0x63, 0x68, 0x00, // f - m a t c h -
+	0x00, 0x00, 0x11, 0x69, 0x66, 0x2d, 0x6d, 0x6f, // - - - i f - m o
+	0x64, 0x69, 0x66, 0x69, 0x65, 0x64, 0x2d, 0x73, // d i f i e d - s
+	0x69, 0x6e, 0x63, 0x65, 0x00, 0x00, 0x00, 0x0d, // i n c e - - - -
+	0x69, 0x66, 0x2d, 0x6e, 0x6f, 0x6e, 0x65, 0x2d, // i f - n o n e -
+	0x6d, 0x61, 0x74, 0x63, 0x68, 0x00, 0x00, 0x00, // m a t c h - - -
+	0x08, 0x69, 0x66, 0x2d, 0x72, 0x61, 0x6e, 0x67, // - i f - r a n g
+	0x65, 0x00, 0x00, 0x00, 0x13, 0x69, 0x66, 0x2d, // e - - - - i f -
+	0x75, 0x6e, 0x6d, 0x6f, 0x64, 0x69, 0x66, 0x69, // u n m o d i f i
+	0x65, 0x64, 0x2d, 0x73, 0x69, 0x6e, 0x63, 0x65, // e d - s i n c e
+	0x00, 0x00, 0x00, 0x0d, 0x6c, 0x61, 0x73, 0x74, // - - - - l a s t
+	0x2d, 0x6d, 0x6f, 0x64, 0x69, 0x66, 0x69, 0x65, // - m o d i f i e
+	0x64, 0x00, 0x00, 0x00, 0x08, 0x6c, 0x6f, 0x63, // d - - - - l o c
+	0x61, 0x74, 0x69, 0x6f, 0x6e, 0x00, 0x00, 0x00, // a t i o n - - -
+	0x0c, 0x6d, 0x61, 0x78, 0x2d, 0x66, 0x6f, 0x72, // - m a x - f o r
+	0x77, 0x61, 0x72, 0x64, 0x73, 0x00, 0x00, 0x00, // w a r d s - - -
+	0x06, 0x70, 0x72, 0x61, 0x67, 0x6d, 0x61, 0x00, // - p r a g m a -
+	0x00, 0x00, 0x12, 0x70, 0x72, 0x6f, 0x78, 0x79, // - - - p r o x y
+	0x2d, 0x61, 0x75, 0x74, 0x68, 0x65, 0x6e, 0x74, // - a u t h e n t
+	0x69, 0x63, 0x61, 0x74, 0x65, 0x00, 0x00, 0x00, // i c a t e - - -
+	0x13, 0x70, 0x72, 0x6f, 0x78, 0x79, 0x2d, 0x61, // - p r o x y - a
+	0x75, 0x74, 0x68, 0x6f, 0x72, 0x69, 0x7a, 0x61, // u t h o r i z a
+	0x74, 0x69, 0x6f, 0x6e, 0x00, 0x00, 0x00, 0x05, // t i o n - - - -
+	0x72, 0x61, 0x6e, 0x67, 0x65, 0x00, 0x00, 0x00, // r a n g e - - -
+	0x07, 0x72, 0x65, 0x66, 0x65, 0x72, 0x65, 0x72, // - r e f e r e r
+	0x00, 0x00, 0x00, 0x0b, 0x72, 0x65, 0x74, 0x72, // - - - - r e t r
+	0x79, 0x2d, 0x61, 0x66, 0x74, 0x65, 0x72, 0x00, // y - a f t e r -
+	0x00, 0x00, 0x06, 0x73, 0x65, 0x72, 0x76, 0x65, // - - - s e r v e
+	0x72, 0x00, 0x00, 0x00, 0x02, 0x74, 0x65, 0x00, // r - - - - t e -
+	0x00, 0x00, 0x07, 0x74, 0x72, 0x61, 0x69, 0x6c, // - - - t r a i l
+	0x65, 0x72, 0x00, 0x00, 0x00, 0x11, 0x74, 0x72, // e r - - - - t r
+	0x61, 0x6e, 0x73, 0x66, 0x65, 0x72, 0x2d, 0x65, // a n s f e r - e
+	0x6e, 0x63, 0x6f, 0x64, 0x69, 0x6e, 0x67, 0x00, // n c o d i n g -
+	0x00, 0x00, 0x07, 0x75, 0x70, 0x67, 0x72, 0x61, // - - - u p g r a
+	0x64, 0x65, 0x00, 0x00, 0x00, 0x0a, 0x75, 0x73, // d e - - - - u s
+	0x65, 0x72, 0x2d, 0x61, 0x67, 0x65, 0x6e, 0x74, // e r - a g e n t
+	0x00, 0x00, 0x00, 0x04, 0x76, 0x61, 0x72, 0x79, // - - - - v a r y
+	0x00, 0x00, 0x00, 0x03, 0x76, 0x69, 0x61, 0x00, // - - - - v i a -
+	0x00, 0x00, 0x07, 0x77, 0x61, 0x72, 0x6e, 0x69, // - - - w a r n i
+	0x6e, 0x67, 0x00, 0x00, 0x00, 0x10, 0x77, 0x77, // n g - - - - w w
+	0x77, 0x2d, 0x61, 0x75, 0x74, 0x68, 0x65, 0x6e, // w - a u t h e n
+	0x74, 0x69, 0x63, 0x61, 0x74, 0x65, 0x00, 0x00, // t i c a t e - -
+	0x00, 0x06, 0x6d, 0x65, 0x74, 0x68, 0x6f, 0x64, // - - m e t h o d
+	0x00, 0x00, 0x00, 0x03, 0x67, 0x65, 0x74, 0x00, // - - - - g e t -
+	0x00, 0x00, 0x06, 0x73, 0x74, 0x61, 0x74, 0x75, // - - - s t a t u
+	0x73, 0x00, 0x00, 0x00, 0x06, 0x32, 0x30, 0x30, // s - - - - 2 0 0
+	0x20, 0x4f, 0x4b, 0x00, 0x00, 0x00, 0x07, 0x76, // - O K - - - - v
+	0x65, 0x72, 0x73, 0x69, 0x6f, 0x6e, 0x00, 0x00, // e r s i o n - -
+	0x00, 0x08, 0x48, 0x54, 0x54, 0x50, 0x2f, 0x31, // - - H T T P - 1
+	0x2e, 0x31, 0x00, 0x00, 0x00, 0x03, 0x75, 0x72, // - 1 - - - - u r
+	0x6c, 0x00, 0x00, 0x00, 0x06, 0x70, 0x75, 0x62, // l - - - - p u b
+	0x6c, 0x69, 0x63, 0x00, 0x00, 0x00, 0x0a, 0x73, // l i c - - - - s
+	0x65, 0x74, 0x2d, 0x63, 0x6f, 0x6f, 0x6b, 0x69, // e t - c o o k i
+	0x65, 0x00, 0x00, 0x00, 0x0a, 0x6b, 0x65, 0x65, // e - - - - k e e
+	0x70, 0x2d, 0x61, 0x6c, 0x69, 0x76, 0x65, 0x00, // p - a l i v e -
+	0x00, 0x00, 0x06, 0x6f, 0x72, 0x69, 0x67, 0x69, // - - - o r i g i
+	0x6e, 0x31, 0x30, 0x30, 0x31, 0x30, 0x31, 0x32, // n 1 0 0 1 0 1 2
+	0x30, 0x31, 0x32, 0x30, 0x32, 0x32, 0x30, 0x35, // 0 1 2 0 2 2 0 5
+	0x32, 0x30, 0x36, 0x33, 0x30, 0x30, 0x33, 0x30, // 2 0 6 3 0 0 3 0
+	0x32, 0x33, 0x30, 0x33, 0x33, 0x30, 0x34, 0x33, // 2 3 0 3 3 0 4 3
+	0x30, 0x35, 0x33, 0x30, 0x36, 0x33, 0x30, 0x37, // 0 5 3 0 6 3 0 7
+	0x34, 0x30, 0x32, 0x34, 0x30, 0x35, 0x34, 0x30, // 4 0 2 4 0 5 4 0
+	0x36, 0x34, 0x30, 0x37, 0x34, 0x30, 0x38, 0x34, // 6 4 0 7 4 0 8 4
+	0x30, 0x39, 0x34, 0x31, 0x30, 0x34, 0x31, 0x31, // 0 9 4 1 0 4 1 1
+	0x34, 0x31, 0x32, 0x34, 0x31, 0x33, 0x34, 0x31, // 4 1 2 4 1 3 4 1
+	0x34, 0x34, 0x31, 0x35, 0x34, 0x31, 0x36, 0x34, // 4 4 1 5 4 1 6 4
+	0x31, 0x37, 0x35, 0x30, 0x32, 0x35, 0x30, 0x34, // 1 7 5 0 2 5 0 4
+	0x35, 0x30, 0x35, 0x32, 0x30, 0x33, 0x20, 0x4e, // 5 0 5 2 0 3 - N
+	0x6f, 0x6e, 0x2d, 0x41, 0x75, 0x74, 0x68, 0x6f, // o n - A u t h o
+	0x72, 0x69, 0x74, 0x61, 0x74, 0x69, 0x76, 0x65, // r i t a t i v e
+	0x20, 0x49, 0x6e, 0x66, 0x6f, 0x72, 0x6d, 0x61, // - I n f o r m a
+	0x74, 0x69, 0x6f, 0x6e, 0x32, 0x30, 0x34, 0x20, // t i o n 2 0 4 -
+	0x4e, 0x6f, 0x20, 0x43, 0x6f, 0x6e, 0x74, 0x65, // N o - C o n t e
+	0x6e, 0x74, 0x33, 0x30, 0x31, 0x20, 0x4d, 0x6f, // n t 3 0 1 - M o
+	0x76, 0x65, 0x64, 0x20, 0x50, 0x65, 0x72, 0x6d, // v e d - P e r m
+	0x61, 0x6e, 0x65, 0x6e, 0x74, 0x6c, 0x79, 0x34, // a n e n t l y 4
+	0x30, 0x30, 0x20, 0x42, 0x61, 0x64, 0x20, 0x52, // 0 0 - B a d - R
+	0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x34, 0x30, // e q u e s t 4 0
+	0x31, 0x20, 0x55, 0x6e, 0x61, 0x75, 0x74, 0x68, // 1 - U n a u t h
+	0x6f, 0x72, 0x69, 0x7a, 0x65, 0x64, 0x34, 0x30, // o r i z e d 4 0
+	0x33, 0x20, 0x46, 0x6f, 0x72, 0x62, 0x69, 0x64, // 3 - F o r b i d
+	0x64, 0x65, 0x6e, 0x34, 0x30, 0x34, 0x20, 0x4e, // d e n 4 0 4 - N
+	0x6f, 0x74, 0x20, 0x46, 0x6f, 0x75, 0x6e, 0x64, // o t - F o u n d
+	0x35, 0x30, 0x30, 0x20, 0x49, 0x6e, 0x74, 0x65, // 5 0 0 - I n t e
+	0x72, 0x6e, 0x61, 0x6c, 0x20, 0x53, 0x65, 0x72, // r n a l - S e r
+	0x76, 0x65, 0x72, 0x20, 0x45, 0x72, 0x72, 0x6f, // v e r - E r r o
+	0x72, 0x35, 0x30, 0x31, 0x20, 0x4e, 0x6f, 0x74, // r 5 0 1 - N o t
+	0x20, 0x49, 0x6d, 0x70, 0x6c, 0x65, 0x6d, 0x65, // - I m p l e m e
+	0x6e, 0x74, 0x65, 0x64, 0x35, 0x30, 0x33, 0x20, // n t e d 5 0 3 -
+	0x53, 0x65, 0x72, 0x76, 0x69, 0x63, 0x65, 0x20, // S e r v i c e -
+	0x55, 0x6e, 0x61, 0x76, 0x61, 0x69, 0x6c, 0x61, // U n a v a i l a
+	0x62, 0x6c, 0x65, 0x4a, 0x61, 0x6e, 0x20, 0x46, // b l e J a n - F
+	0x65, 0x62, 0x20, 0x4d, 0x61, 0x72, 0x20, 0x41, // e b - M a r - A
+	0x70, 0x72, 0x20, 0x4d, 0x61, 0x79, 0x20, 0x4a, // p r - M a y - J
+	0x75, 0x6e, 0x20, 0x4a, 0x75, 0x6c, 0x20, 0x41, // u n - J u l - A
+	0x75, 0x67, 0x20, 0x53, 0x65, 0x70, 0x74, 0x20, // u g - S e p t -
+	0x4f, 0x63, 0x74, 0x20, 0x4e, 0x6f, 0x76, 0x20, // O c t - N o v -
+	0x44, 0x65, 0x63, 0x20, 0x30, 0x30, 0x3a, 0x30, // D e c - 0 0 - 0
+	0x30, 0x3a, 0x30, 0x30, 0x20, 0x4d, 0x6f, 0x6e, // 0 - 0 0 - M o n
+	0x2c, 0x20, 0x54, 0x75, 0x65, 0x2c, 0x20, 0x57, // - - T u e - - W
+	0x65, 0x64, 0x2c, 0x20, 0x54, 0x68, 0x75, 0x2c, // e d - - T h u -
+	0x20, 0x46, 0x72, 0x69, 0x2c, 0x20, 0x53, 0x61, // - F r i - - S a
+	0x74, 0x2c, 0x20, 0x53, 0x75, 0x6e, 0x2c, 0x20, // t - - S u n - -
+	0x47, 0x4d, 0x54, 0x63, 0x68, 0x75, 0x6e, 0x6b, // G M T c h u n k
+	0x65, 0x64, 0x2c, 0x74, 0x65, 0x78, 0x74, 0x2f, // e d - t e x t -
+	0x68, 0x74, 0x6d, 0x6c, 0x2c, 0x69, 0x6d, 0x61, // h t m l - i m a
+	0x67, 0x65, 0x2f, 0x70, 0x6e, 0x67, 0x2c, 0x69, // g e - p n g - i
+	0x6d, 0x61, 0x67, 0x65, 0x2f, 0x6a, 0x70, 0x67, // m a g e - j p g
+	0x2c, 0x69, 0x6d, 0x61, 0x67, 0x65, 0x2f, 0x67, // - i m a g e - g
+	0x69, 0x66, 0x2c, 0x61, 0x70, 0x70, 0x6c, 0x69, // i f - a p p l i
+	0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x2f, 0x78, // c a t i o n - x
+	0x6d, 0x6c, 0x2c, 0x61, 0x70, 0x70, 0x6c, 0x69, // m l - a p p l i
+	0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x2f, 0x78, // c a t i o n - x
+	0x68, 0x74, 0x6d, 0x6c, 0x2b, 0x78, 0x6d, 0x6c, // h t m l - x m l
+	0x2c, 0x74, 0x65, 0x78, 0x74, 0x2f, 0x70, 0x6c, // - t e x t - p l
+	0x61, 0x69, 0x6e, 0x2c, 0x74, 0x65, 0x78, 0x74, // a i n - t e x t
+	0x2f, 0x6a, 0x61, 0x76, 0x61, 0x73, 0x63, 0x72, // - j a v a s c r
+	0x69, 0x70, 0x74, 0x2c, 0x70, 0x75, 0x62, 0x6c, // i p t - p u b l
+	0x69, 0x63, 0x70, 0x72, 0x69, 0x76, 0x61, 0x74, // i c p r i v a t
+	0x65, 0x6d, 0x61, 0x78, 0x2d, 0x61, 0x67, 0x65, // e m a x - a g e
+	0x3d, 0x67, 0x7a, 0x69, 0x70, 0x2c, 0x64, 0x65, // - g z i p - d e
+	0x66, 0x6c, 0x61, 0x74, 0x65, 0x2c, 0x73, 0x64, // f l a t e - s d
+	0x63, 0x68, 0x63, 0x68, 0x61, 0x72, 0x73, 0x65, // c h c h a r s e
+	0x74, 0x3d, 0x75, 0x74, 0x66, 0x2d, 0x38, 0x63, // t - u t f - 8 c
+	0x68, 0x61, 0x72, 0x73, 0x65, 0x74, 0x3d, 0x69, // h a r s e t - i
+	0x73, 0x6f, 0x2d, 0x38, 0x38, 0x35, 0x39, 0x2d, // s o - 8 8 5 9 -
+	0x31, 0x2c, 0x75, 0x74, 0x66, 0x2d, 0x2c, 0x2a, // 1 - u t f - - -
+	0x2c, 0x65, 0x6e, 0x71, 0x3d, 0x30, 0x2e, // - e n q - 0 -
+}

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

@@ -2,7 +2,7 @@ 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/views
+        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+

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/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

@@ -156,8 +156,7 @@ func runExitNodeSuggest(ctx context.Context, args []string) error {
 		fmt.Println("No exit node suggestion is available.")
 		return nil
 	}
-	hostname := strings.TrimSuffix(res.Name, ".")
-	fmt.Printf("Suggested exit node: %v\nTo accept this suggestion, use `tailscale set --exit-node=%v`.\n", hostname, shellquote.Join(hostname))
+	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
 }
 

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/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

@@ -9,7 +9,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
    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/views
+        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+

cmd/tailscaled/depaware.txt

@@ -90,7 +90,7 @@ 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/views
+        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+
@@ -402,6 +402,7 @@ 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+

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 +72,93 @@ 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}
+}
+
+type GenericBasicStruct[T BasicType] struct {
+	Value T
+}
+
+type StructWithContainers struct {
+	IntContainer             Container[int]
+	CloneableContainer       Container[*StructWithPtrs]
+	BasicGenericContainer    Container[GenericBasicStruct[int]]
+	ClonableGenericContainer Container[*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 +234,206 @@ 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.ClonableGenericContainer = *src.ClonableGenericContainer.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]]
+	ClonableGenericContainer Container[*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 +377,294 @@ 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) ClonableGenericContainer() ContainerView[*GenericNoPtrsStruct[int], GenericNoPtrsStructView[int]] {
+	return ContainerViewOf(&v.ж.ClonableGenericContainer)
+}
+
+// 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]]
+	ClonableGenericContainer Container[*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(0)).(*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/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 (

control/controlknobs/controlknobs.go

@@ -95,6 +95,10 @@ 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
 }
 
 // UpdateFromNodeAttributes updates k (if non-nil) based on the provided self
@@ -122,6 +126,7 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
 		userDialUseRoutes                    = has(tailcfg.NodeAttrUserDialUseRoutes)
 		disableSplitDNSWhenNoCustomResolvers = has(tailcfg.NodeAttrDisableSplitDNSWhenNoCustomResolvers)
 		disableLocalDNSOverrideViaNRPT       = has(tailcfg.NodeAttrDisableLocalDNSOverrideViaNRPT)
+		disableCryptorouting                 = has(tailcfg.NodeAttrDisableMagicSockCryptoRouting)
 	)
 
 	if has(tailcfg.NodeAttrOneCGNATEnable) {
@@ -147,6 +152,7 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
 	k.UserDialUseRoutes.Store(userDialUseRoutes)
 	k.DisableSplitDNSWhenNoCustomResolvers.Store(disableSplitDNSWhenNoCustomResolvers)
 	k.DisableLocalDNSOverrideViaNRPT.Store(disableLocalDNSOverrideViaNRPT)
+	k.DisableCryptorouting.Store(disableCryptorouting)
 }
 
 // AsDebugJSON returns k as something that can be marshalled with json.Marshal
@@ -173,5 +179,6 @@ func (k *Knobs) AsDebugJSON() map[string]any {
 		"UserDialUseRoutes":                    k.UserDialUseRoutes.Load(),
 		"DisableSplitDNSWhenNoCustomResolvers": k.DisableSplitDNSWhenNoCustomResolvers.Load(),
 		"DisableLocalDNSOverrideViaNRPT":       k.DisableLocalDNSOverrideViaNRPT.Load(),
+		"DisableCryptorouting":                 k.DisableCryptorouting.Load(),
 	}
 }

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/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

flake.nix

@@ -120,4 +120,4 @@
   in
     flake-utils.lib.eachDefaultSystem (system: flakeForSystem nixpkgs system);
 }
-# nix-direnv cache busting line: sha256-bQ1RvNNMKw8HA7paIq9XgtSfc4LvqyNhu/rQEh+IOts=
+# nix-direnv cache busting line: sha256-2x9Ns5o6oenCcsHkOFjoCz/R5YjPwJEImK0a1valYBE=

go.mod

@@ -4,7 +4,6 @@ go 1.22.0
 
 require (
 	filippo.io/mkcert v1.4.4
-	fybrik.io/crdoc v0.6.3
 	github.com/akutz/memconn v0.1.0
 	github.com/alexbrainman/sspi v0.0.0-20231016080023-1a75b4708caa
 	github.com/andybalholm/brotli v1.1.0
@@ -20,7 +19,6 @@ require (
 	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
 	github.com/creack/pty v1.1.21
 	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
@@ -30,7 +28,7 @@ require (
 	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
@@ -44,7 +42,6 @@ require (
 	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

go.mod.sri

@@ -1 +1 @@
-sha256-bQ1RvNNMKw8HA7paIq9XgtSfc4LvqyNhu/rQEh+IOts=
+sha256-2x9Ns5o6oenCcsHkOFjoCz/R5YjPwJEImK0a1valYBE=

go.sum

@@ -46,8 +46,6 @@ filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
 filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
 filippo.io/mkcert v1.4.4 h1:8eVbbwfVlaqUM7OwuftKc2nuYOoTDQWqsoXmzoXZdbc=
 filippo.io/mkcert v1.4.4/go.mod h1:VyvOchVuAye3BoUsPUOOofKygVwLV2KQMVFJNRq+1dA=
-fybrik.io/crdoc v0.6.3 h1:jNNAVINu8up5vrLa0jrV7z7HSlyHF/6lNOrAtrXwYlI=
-fybrik.io/crdoc v0.6.3/go.mod h1:kvZRt7VAzOyrmDpIqREtcKAVFSJYEBoAyniYebsJGtQ=
 github.com/Abirdcfly/dupword v0.0.11 h1:z6v8rMETchZXUIuHxYNmlUAuKuB21PeaSymTed16wgU=
 github.com/Abirdcfly/dupword v0.0.11/go.mod h1:wH8mVGuf3CP5fsBTkfWwwwKTjDnVVCxtU8d8rgeVYXA=
 github.com/AlekSi/pointer v1.2.0 h1:glcy/gc4h8HnG2Z3ZECSzZ1IX1x2JxRVuDzaJwQE0+w=
@@ -242,8 +240,6 @@ github.com/dave/brenda v1.1.0 h1:Sl1LlwXnbw7xMhq3y2x11McFu43AjDcwkllxxgZ3EZw=
 github.com/dave/brenda v1.1.0/go.mod h1:4wCUr6gSlu5/1Tk7akE5X7UorwiQ8Rij0SKH3/BGMOM=
 github.com/dave/courtney v0.4.0 h1:Vb8hi+k3O0h5++BR96FIcX0x3NovRbnhGd/dRr8inBk=
 github.com/dave/courtney v0.4.0/go.mod h1:3WSU3yaloZXYAxRuWt8oRyVb9SaRiMBt5Kz/2J227tM=
-github.com/dave/jennifer v1.7.0 h1:uRbSBH9UTS64yXbh4FrMHfgfY762RD+C7bUPKODpSJE=
-github.com/dave/jennifer v1.7.0/go.mod h1:nXbxhEmQfOZhWml3D1cDK5M1FLnMSozpbFN/m3RmGZc=
 github.com/dave/patsy v0.0.0-20210517141501-957256f50cba h1:1o36L4EKbZzazMk8iGC4kXpVnZ6TPxR2mZ9qVKjNNAs=
 github.com/dave/patsy v0.0.0-20210517141501-957256f50cba/go.mod h1:qfR88CgEGLoiqDaE+xxDCi5QA5v4vUoW0UCX2Nd5Tlc=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -312,8 +308,8 @@ github.com/fxamacker/cbor/v2 v2.6.0 h1:sU6J2usfADwWlYDAFhZBQ6TnLFBHxgesMrQfQgk1t
 github.com/fxamacker/cbor/v2 v2.6.0/go.mod h1:pxXPTn3joSm21Gbwsv0w9OSA2y1HFR9qXEeXQVeNoDQ=
 github.com/fzipp/gocyclo v0.6.0 h1:lsblElZG7d3ALtGMx9fmxeTKZaLLpU8mET09yN4BBLo=
 github.com/fzipp/gocyclo v0.6.0/go.mod h1:rXPyn8fnlpa0R2csP/31uerbiVBugk5whMdlyaLkLoA=
-github.com/gaissmai/bart v0.4.1 h1:G1t58voWkNmT47lBDawH5QhtTDsdqRIO+ftq5x4P9Ls=
-github.com/gaissmai/bart v0.4.1/go.mod h1:KHeYECXQiBjTzQz/om2tqn3sZF1J7hw9m6z41ftj3fg=
+github.com/gaissmai/bart v0.11.1 h1:5Uv5XwsaFBRo4E5VBcb9TzY8B7zxFf+U7isDxqOrRfc=
+github.com/gaissmai/bart v0.11.1/go.mod h1:KHeYECXQiBjTzQz/om2tqn3sZF1J7hw9m6z41ftj3fg=
 github.com/github/fakeca v0.1.0 h1:Km/MVOFvclqxPM9dZBC4+QE564nU4gz4iZ0D9pMw28I=
 github.com/github/fakeca v0.1.0/go.mod h1:+bormgoGMMuamOscx7N91aOuUST7wdaJ2rNjeohylyo=
 github.com/gliderlabs/ssh v0.3.5 h1:OcaySEmAQJgyYcArR+gGGTHCyE7nvhEMTlYY+Dp8CpY=
@@ -548,8 +544,6 @@ github.com/huandu/xstrings v1.4.0 h1:D17IlohoQq4UcpqD7fDk80P7l+lwAmlFaBHgOipl2FU
 github.com/huandu/xstrings v1.4.0/go.mod h1:y5/lhBue+AyNmUVz9RLU9xbLR0o4KIIExikq4ovT0aE=
 github.com/hugelgupf/vmtest v0.0.0-20240102225328-693afabdd27f h1:ov45/OzrJG8EKbGjn7jJZQJTN7Z1t73sFYNIRd64YlI=
 github.com/hugelgupf/vmtest v0.0.0-20240102225328-693afabdd27f/go.mod h1:JoDrYMZpDPYo6uH9/f6Peqms3zNNWT2XiGgioMOIGuI=
-github.com/iancoleman/strcase v0.3.0 h1:nTXanmYxhfFAMjZL34Ov6gkzEsSJZ5DbhxWjvSASxEI=
-github.com/iancoleman/strcase v0.3.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/illarion/gonotify v1.0.1 h1:F1d+0Fgbq/sDWjj/r66ekjDG+IDeecQKUFH4wNwsoio=

health/health.go

@@ -69,6 +69,9 @@ type Tracker struct {
 
 	warnables   []*Warnable // keys ever set
 	warnableVal map[*Warnable]*warningState
+	// pendingVisibleTimers contains timers for Warnables that are unhealthy, but are
+	// not visible to the user yet, because they haven't been unhealthy for TimeToVisible
+	pendingVisibleTimers map[*Warnable]*time.Timer
 
 	// sysErr maps subsystems to their current error (or nil if the subsystem is healthy)
 	// Deprecated: using Warnables should be preferred
@@ -162,6 +165,7 @@ func Register(w *Warnable) *Warnable {
 	if registeredWarnables[w.Code] != nil {
 		panic(fmt.Sprintf("health: a Warnable with code %q was already registered", w.Code))
 	}
+
 	mak.Set(&registeredWarnables, w.Code, w)
 	return w
 }
@@ -218,6 +222,11 @@ type Warnable struct {
 	// the client GUI supports a tray icon, the client will display an exclamation mark
 	// on the tray icon when ImpactsConnectivity is set to true and the Warnable is unhealthy.
 	ImpactsConnectivity bool
+
+	// TimeToVisible is the Duration that the Warnable has to be in an unhealthy state before it
+	// should be surfaced as unhealthy to the user. This is used to prevent transient errors from being
+	// displayed to the user.
+	TimeToVisible time.Duration
 }
 
 // StaticMessage returns a function that always returns the input string, to be used in
@@ -291,6 +300,15 @@ func (ws *warningState) Equal(other *warningState) bool {
 	return ws.BrokenSince.Equal(other.BrokenSince) && maps.Equal(ws.Args, other.Args)
 }
 
+// IsVisible returns whether the Warnable should be visible to the user, based on the TimeToVisible
+// field of the Warnable and the BrokenSince time when the Warnable became unhealthy.
+func (w *Warnable) IsVisible(ws *warningState) bool {
+	if ws == nil || w.TimeToVisible == 0 {
+		return true
+	}
+	return time.Since(ws.BrokenSince) >= w.TimeToVisible
+}
+
 // SetUnhealthy sets a warningState for the given Warnable with the provided Args, and should be
 // called when a Warnable becomes unhealthy, or its unhealthy status needs to be updated.
 // SetUnhealthy takes ownership of args. The args can be nil if no additional information is
@@ -327,7 +345,27 @@ func (t *Tracker) setUnhealthyLocked(w *Warnable, args Args) {
 	mak.Set(&t.warnableVal, w, ws)
 	if !ws.Equal(prevWs) {
 		for _, cb := range t.watchers {
-			go cb(w, w.unhealthyState(ws))
+			// If the Warnable has been unhealthy for more than its TimeToVisible, the callback should be
+			// executed immediately. Otherwise, the callback should be enqueued to run once the Warnable
+			// becomes visible.
+			if w.IsVisible(ws) {
+				go cb(w, w.unhealthyState(ws))
+				continue
+			}
+
+			// The time remaining until the Warnable will be visible to the user is the TimeToVisible
+			// minus the time that has already passed since the Warnable became unhealthy.
+			visibleIn := w.TimeToVisible - time.Since(brokenSince)
+			mak.Set(&t.pendingVisibleTimers, w, time.AfterFunc(visibleIn, func() {
+				t.mu.Lock()
+				defer t.mu.Unlock()
+				// Check if the Warnable is still unhealthy, as it could have become healthy between the time
+				// the timer was set for and the time it was executed.
+				if t.warnableVal[w] != nil {
+					go cb(w, w.unhealthyState(ws))
+					delete(t.pendingVisibleTimers, w)
+				}
+			}))
 		}
 	}
 }
@@ -349,6 +387,13 @@ func (t *Tracker) setHealthyLocked(w *Warnable) {
 	}
 
 	delete(t.warnableVal, w)
+
+	// Stop any pending visiblity timers for this Warnable
+	if canc, ok := t.pendingVisibleTimers[w]; ok {
+		canc.Stop()
+		delete(t.pendingVisibleTimers, w)
+	}
+
 	for _, cb := range t.watchers {
 		go cb(w, nil)
 	}
@@ -861,6 +906,10 @@ func (t *Tracker) Strings() []string {
 func (t *Tracker) stringsLocked() []string {
 	result := []string{}
 	for w, ws := range t.warnableVal {
+		if !w.IsVisible(ws) {
+			// Do not append invisible warnings.
+			continue
+		}
 		if ws.Args == nil {
 			result = append(result, w.Text(Args{}))
 		} else {

health/health_test.go

@@ -162,6 +162,51 @@ func TestWatcher(t *testing.T) {
 	}
 }
 
+// TestWatcherWithTimeToVisible tests that a registered watcher function gets called with the correct
+// Warnable and non-nil/nil UnhealthyState upon setting a Warnable to unhealthy/healthy, but the Warnable
+// has a TimeToVisible set, which means that a watcher should only be notified of an unhealthy state after
+// the TimeToVisible duration has passed.
+func TestSetUnhealthyWithTimeToVisible(t *testing.T) {
+	ht := Tracker{}
+	mw := Register(&Warnable{
+		Code:                "test-warnable-3-secs-to-visible",
+		Title:               "Test Warnable with 3 seconds to visible",
+		Text:                StaticMessage("Hello world"),
+		TimeToVisible:       2 * time.Second,
+		ImpactsConnectivity: true,
+	})
+	defer unregister(mw)
+
+	becameUnhealthy := make(chan struct{})
+	becameHealthy := make(chan struct{})
+
+	watchFunc := func(w *Warnable, us *UnhealthyState) {
+		if w != mw {
+			t.Fatalf("watcherFunc was called, but with an unexpected Warnable: %v, want: %v", w, w)
+		}
+
+		if us != nil {
+			becameUnhealthy <- struct{}{}
+		} else {
+			becameHealthy <- struct{}{}
+		}
+	}
+
+	ht.RegisterWatcher(watchFunc)
+	ht.SetUnhealthy(mw, Args{ArgError: "Hello world"})
+
+	select {
+	case <-becameUnhealthy:
+		// Test failed because the watcher got notified of an unhealthy state
+		t.Fatalf("watcherFunc was called with an unhealthy state")
+	case <-becameHealthy:
+		// Test failed because the watcher got of a healthy state
+		t.Fatalf("watcherFunc was called with a healthy state")
+	case <-time.After(1 * time.Second):
+		// As expected, watcherFunc still had not been called after 1 second
+	}
+}
+
 func TestRegisterWarnablePanicsWithDuplicate(t *testing.T) {
 	w := &Warnable{
 		Code: "test-warnable-1",

health/state.go

@@ -20,7 +20,7 @@ type State struct {
 	Warnings map[WarnableCode]UnhealthyState
 }
 
-// Representation contains information to be shown to the user to inform them
+// UnhealthyState contains information to be shown to the user to inform them
 // that a Warnable is currently unhealthy.
 type UnhealthyState struct {
 	WarnableCode        WarnableCode
@@ -86,6 +86,10 @@ func (t *Tracker) CurrentState() *State {
 	wm := map[WarnableCode]UnhealthyState{}
 
 	for w, ws := range t.warnableVal {
+		if !w.IsVisible(ws) {
+			// Skip invisible Warnables.
+			continue
+		}
 		wm[w.Code] = *w.unhealthyState(ws)
 	}
 

health/warnings.go

@@ -59,6 +59,7 @@ var NetworkStatusWarnable = Register(&Warnable{
 	Severity:            SeverityMedium,
 	Text:                StaticMessage("Tailscale cannot connect because the network is down. Check your Internet connection."),
 	ImpactsConnectivity: true,
+	TimeToVisible:       5 * time.Second,
 })
 
 // IPNStateWarnable is a Warnable that warns the user that Tailscale is stopped.
@@ -101,6 +102,8 @@ var notInMapPollWarnable = Register(&Warnable{
 	Severity:  SeverityMedium,
 	DependsOn: []*Warnable{NetworkStatusWarnable},
 	Text:      StaticMessage("Unable to connect to the Tailscale coordination server to synchronize the state of your tailnet. Peer reachability might degrade over time."),
+	// 8 minutes reflects a maximum maintenance window for the coordination server.
+	TimeToVisible: 8 * time.Minute,
 })
 
 // noDERPHomeWarnable is a Warnable that warns the user that Tailscale doesn't have a home DERP.
@@ -111,6 +114,7 @@ var noDERPHomeWarnable = Register(&Warnable{
 	DependsOn:           []*Warnable{NetworkStatusWarnable},
 	Text:                StaticMessage("Tailscale could not connect to any relay server. Check your Internet connection."),
 	ImpactsConnectivity: true,
+	TimeToVisible:       10 * time.Second,
 })
 
 // noDERPConnectionWarnable is a Warnable that warns the user that Tailscale couldn't connect to a specific DERP server.
@@ -127,6 +131,7 @@ var noDERPConnectionWarnable = Register(&Warnable{
 		}
 	},
 	ImpactsConnectivity: true,
+	TimeToVisible:       10 * time.Second,
 })
 
 // derpTimeoutWarnable is a Warnable that warns the user that Tailscale hasn't heard from the home DERP region for a while.

hostinfo/hostinfo_linux.go

@@ -159,7 +159,14 @@ func linuxVersionMeta() (meta versionMeta) {
 	return
 }
 
+// linuxBuildTagPackageType is set by packagetype_*.go
+// build tag guarded files.
+var linuxBuildTagPackageType string
+
 func packageTypeLinux() string {
+	if v := linuxBuildTagPackageType; v != "" {
+		return v
+	}
 	// Report whether this is in a snap.
 	// See https://snapcraft.io/docs/environment-variables
 	// We just look at two somewhat arbitrarily.

hostinfo/packagetype_container.go

@@ -0,0 +1,10 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build linux && ts_package_container
+
+package hostinfo
+
+func init() {
+	linuxBuildTagPackageType = "container"
+}

internal/tooldeps/tooldeps.go

@@ -3,6 +3,8 @@
 
 //go:build for_go_mod_tidy_only
 
+// Package tooldeps contains dependencies for tools used in the Tailscale repository,
+// so they're not removed by "go mod tidy".
 package tooldeps
 
 import (

ipn/conf.go

@@ -42,6 +42,10 @@ type ConfigVAlpha struct {
 	AutoUpdate      *AutoUpdatePrefs `json:",omitempty"`
 	ServeConfigTemp *ServeConfig     `json:",omitempty"` // TODO(bradfitz,maisem): make separate stable type for this
 
+	// StaticEndpoints are additional, user-defined endpoints that this node
+	// should advertise amongst its wireguard endpoints.
+	StaticEndpoints []netip.AddrPort `json:",omitempty"`
+
 	// TODO(bradfitz,maisem): future something like:
 	// Profile map[string]*Config // keyed by alice@gmail.com, corp.com (TailnetSID)
 }

ipn/ipn_clone.go

@@ -14,6 +14,7 @@ import (
 	"tailscale.com/types/opt"
 	"tailscale.com/types/persist"
 	"tailscale.com/types/preftype"
+	"tailscale.com/types/ptr"
 )
 
 // Clone makes a deep copy of Prefs.
@@ -29,7 +30,11 @@ func (src *Prefs) Clone() *Prefs {
 	if src.DriveShares != nil {
 		dst.DriveShares = make([]*drive.Share, len(src.DriveShares))
 		for i := range dst.DriveShares {
-			dst.DriveShares[i] = src.DriveShares[i].Clone()
+			if src.DriveShares[i] == nil {
+				dst.DriveShares[i] = nil
+			} else {
+				dst.DriveShares[i] = src.DriveShares[i].Clone()
+			}
 		}
 	}
 	dst.Persist = src.Persist.Clone()
@@ -81,20 +86,32 @@ func (src *ServeConfig) Clone() *ServeConfig {
 	if dst.TCP != nil {
 		dst.TCP = map[uint16]*TCPPortHandler{}
 		for k, v := range src.TCP {
-			dst.TCP[k] = v.Clone()
+			if v == nil {
+				dst.TCP[k] = nil
+			} else {
+				dst.TCP[k] = ptr.To(*v)
+			}
 		}
 	}
 	if dst.Web != nil {
 		dst.Web = map[HostPort]*WebServerConfig{}
 		for k, v := range src.Web {
-			dst.Web[k] = v.Clone()
+			if v == nil {
+				dst.Web[k] = nil
+			} else {
+				dst.Web[k] = v.Clone()
+			}
 		}
 	}
 	dst.AllowFunnel = maps.Clone(src.AllowFunnel)
 	if dst.Foreground != nil {
 		dst.Foreground = map[string]*ServeConfig{}
 		for k, v := range src.Foreground {
-			dst.Foreground[k] = v.Clone()
+			if v == nil {
+				dst.Foreground[k] = nil
+			} else {
+				dst.Foreground[k] = v.Clone()
+			}
 		}
 	}
 	return dst
@@ -157,7 +174,11 @@ func (src *WebServerConfig) Clone() *WebServerConfig {
 	if dst.Handlers != nil {
 		dst.Handlers = map[string]*HTTPHandler{}
 		for k, v := range src.Handlers {
-			dst.Handlers[k] = v.Clone()
+			if v == nil {
+				dst.Handlers[k] = nil
+			} else {
+				dst.Handlers[k] = ptr.To(*v)
+			}
 		}
 	}
 	return dst

ipn/ipnlocal/autoupdate.go

@@ -11,6 +11,7 @@ import (
 
 	"tailscale.com/clientupdate"
 	"tailscale.com/ipn"
+	"tailscale.com/version"
 )
 
 func (b *LocalBackend) stopOfflineAutoUpdate() {
@@ -30,6 +31,10 @@ func (b *LocalBackend) maybeStartOfflineAutoUpdate(prefs ipn.PrefsView) {
 	if !clientupdate.CanAutoUpdate() {
 		return
 	}
+	// On macsys, auto-updates are managed by Sparkle.
+	if version.IsMacSysExt() {
+		return
+	}
 
 	if b.offlineAutoUpdateCancel != nil {
 		// Already running.

ipn/ipnlocal/c2n.go

@@ -318,7 +318,7 @@ func handleC2NPostureIdentityGet(b *LocalBackend, w http.ResponseWriter, r *http
 
 	res := tailcfg.C2NPostureIdentityResponse{}
 
-	// Only collect serial numbers if enabled on the client,
+	// Only collect posture identity if enabled on the client,
 	// this will first check syspolicy, MDM settings like Registry
 	// on Windows or defaults on macOS. If they are not set, it falls
 	// back to the cli-flag, `--posture-checking`.
@@ -337,8 +337,17 @@ func handleC2NPostureIdentityGet(b *LocalBackend, w http.ResponseWriter, r *http
 			http.Error(w, err.Error(), http.StatusInternalServerError)
 			return
 		}
-
 		res.SerialNumbers = sns
+
+		// TODO(tailscale/corp#21371, 2024-07-10): once this has landed in a stable release
+		// and looks good in client metrics, remove this parameter and always report MAC
+		// addresses.
+		if r.FormValue("hwaddrs") == "true" {
+			res.IfaceHardwareAddrs, err = posture.GetHardwareAddrs()
+			if err != nil {
+				b.logf("c2n: GetHardwareAddrs returned error: %v", err)
+			}
+		}
 	} else {
 		res.PostureDisabled = true
 	}
@@ -355,7 +364,7 @@ func (b *LocalBackend) newC2NUpdateResponse() tailcfg.C2NUpdateResponse {
 	prefs := b.Prefs().AutoUpdate()
 	return tailcfg.C2NUpdateResponse{
 		Enabled:   envknob.AllowsRemoteUpdate() || prefs.Apply.EqualBool(true),
-		Supported: clientupdate.CanAutoUpdate(),
+		Supported: clientupdate.CanAutoUpdate() && !version.IsMacSysExt(),
 	}
 }
 
@@ -441,9 +450,13 @@ func tailscaleUpdateCmd(cmdTS string) *exec.Cmd {
 	// tailscaled is restarted during the update, systemd won't kill this
 	// temporary update unit, which could cause unexpected breakage.
 	//
-	// We want to use the --wait flag for systemd-run, to block the update
-	// command until completion and collect output. But this flag was added in
-	// systemd 232, so we need to check the version first.
+	// We want to use a few optional flags:
+	//  * --wait, to block the update command until completion (added in systemd 232)
+	//  * --pipe, to collect stdout/stderr (added in systemd 235)
+	//  * --collect, to clean up failed runs from memory (added in systemd 236)
+	//
+	// We need to check the version of systemd to figure out if those flags are
+	// available.
 	//
 	// The output will look like:
 	//
@@ -461,10 +474,14 @@ func tailscaleUpdateCmd(cmdTS string) *exec.Cmd {
 	if err != nil {
 		return defaultCmd
 	}
-	if systemdVer < 232 {
-		return exec.Command("systemd-run", "--pipe", "--collect", cmdTS, "update", "--yes")
-	} else {
+	if systemdVer >= 236 {
 		return exec.Command("systemd-run", "--wait", "--pipe", "--collect", cmdTS, "update", "--yes")
+	} else if systemdVer >= 235 {
+		return exec.Command("systemd-run", "--wait", "--pipe", cmdTS, "update", "--yes")
+	} else if systemdVer >= 232 {
+		return exec.Command("systemd-run", "--wait", cmdTS, "update", "--yes")
+	} else {
+		return exec.Command("systemd-run", cmdTS, "update", "--yes")
 	}
 }
 

ipn/ipnlocal/cert.go

@@ -88,6 +88,17 @@ var acmeDebug = envknob.RegisterBool("TS_DEBUG_ACME")
 // If a cert is expired, it will be renewed synchronously otherwise it will be
 // renewed asynchronously.
 func (b *LocalBackend) GetCertPEM(ctx context.Context, domain string) (*TLSCertKeyPair, error) {
+	return b.GetCertPEMWithValidity(ctx, domain, 0)
+}
+
+// GetCertPEMWithValidity gets the TLSCertKeyPair for domain, either from cache
+// or via the ACME process. ACME process is used for new domain certs, existing
+// expired certs or existing certs that should get renewed sooner than
+// minValidity.
+//
+// If a cert is expired, or expires sooner than minValidity, it will be renewed
+// synchronously. Otherwise it will be renewed asynchronously.
+func (b *LocalBackend) GetCertPEMWithValidity(ctx context.Context, domain string, minValidity time.Duration) (*TLSCertKeyPair, error) {
 	if !validLookingCertDomain(domain) {
 		return nil, errors.New("invalid domain")
 	}
@@ -109,17 +120,28 @@ func (b *LocalBackend) GetCertPEM(ctx context.Context, domain string) (*TLSCertK
 	if pair, err := getCertPEMCached(cs, domain, now); err == nil {
 		// If we got here, we have a valid unexpired cert.
 		// Check whether we should start an async renewal.
-		if shouldRenew, err := b.shouldStartDomainRenewal(cs, domain, now, pair); err != nil {
+		shouldRenew, err := b.shouldStartDomainRenewal(cs, domain, now, pair, minValidity)
+		if err != nil {
 			logf("error checking for certificate renewal: %v", err)
-		} else if shouldRenew {
-			logf("starting async renewal")
-			// Start renewal in the background.
-			go b.getCertPEM(context.Background(), cs, logf, traceACME, domain, now)
+			// Renewal check failed, but the current cert is valid and not
+			// expired, so it's safe to return.
+			return pair, nil
 		}
-		return pair, nil
+		if !shouldRenew {
+			return pair, nil
+		}
+		if minValidity == 0 {
+			logf("starting async renewal")
+			// Start renewal in the background, return current valid cert.
+			go b.getCertPEM(context.Background(), cs, logf, traceACME, domain, now, minValidity)
+			return pair, nil
+		}
+		// If the caller requested a specific validity duration, fall through
+		// to synchronous renewal to fulfill that.
+		logf("starting sync renewal")
 	}
 
-	pair, err := b.getCertPEM(ctx, cs, logf, traceACME, domain, now)
+	pair, err := b.getCertPEM(ctx, cs, logf, traceACME, domain, now, minValidity)
 	if err != nil {
 		logf("getCertPEM: %v", err)
 		return nil, err
@@ -129,7 +151,14 @@ func (b *LocalBackend) GetCertPEM(ctx context.Context, domain string) (*TLSCertK
 
 // shouldStartDomainRenewal reports whether the domain's cert should be renewed
 // based on the current time, the cert's expiry, and the ARI check.
-func (b *LocalBackend) shouldStartDomainRenewal(cs certStore, domain string, now time.Time, pair *TLSCertKeyPair) (bool, error) {
+func (b *LocalBackend) shouldStartDomainRenewal(cs certStore, domain string, now time.Time, pair *TLSCertKeyPair, minValidity time.Duration) (bool, error) {
+	if minValidity != 0 {
+		cert, err := pair.parseCertificate()
+		if err != nil {
+			return false, fmt.Errorf("parsing certificate: %w", err)
+		}
+		return cert.NotAfter.Sub(now) < minValidity, nil
+	}
 	renewMu.Lock()
 	defer renewMu.Unlock()
 	if renewAt, ok := renewCertAt[domain]; ok {
@@ -157,11 +186,7 @@ func (b *LocalBackend) domainRenewed(domain string) {
 }
 
 func (b *LocalBackend) domainRenewalTimeByExpiry(pair *TLSCertKeyPair) (time.Time, error) {
-	block, _ := pem.Decode(pair.CertPEM)
-	if block == nil {
-		return time.Time{}, fmt.Errorf("parsing certificate PEM")
-	}
-	cert, err := x509.ParseCertificate(block.Bytes)
+	cert, err := pair.parseCertificate()
 	if err != nil {
 		return time.Time{}, fmt.Errorf("parsing certificate: %w", err)
 	}
@@ -366,6 +391,17 @@ type TLSCertKeyPair struct {
 	Cached  bool   // whether result came from cache
 }
 
+func (kp TLSCertKeyPair) parseCertificate() (*x509.Certificate, error) {
+	block, _ := pem.Decode(kp.CertPEM)
+	if block == nil {
+		return nil, fmt.Errorf("error parsing certificate PEM")
+	}
+	if block.Type != "CERTIFICATE" {
+		return nil, fmt.Errorf("PEM block is %q, not a CERTIFICATE", block.Type)
+	}
+	return x509.ParseCertificate(block.Bytes)
+}
+
 func keyFile(dir, domain string) string  { return filepath.Join(dir, domain+".key") }
 func certFile(dir, domain string) string { return filepath.Join(dir, domain+".crt") }
 
@@ -383,7 +419,7 @@ func getCertPEMCached(cs certStore, domain string, now time.Time) (p *TLSCertKey
 	return cs.Read(domain, now)
 }
 
-func (b *LocalBackend) getCertPEM(ctx context.Context, cs certStore, logf logger.Logf, traceACME func(any), domain string, now time.Time) (*TLSCertKeyPair, error) {
+func (b *LocalBackend) getCertPEM(ctx context.Context, cs certStore, logf logger.Logf, traceACME func(any), domain string, now time.Time, minValidity time.Duration) (*TLSCertKeyPair, error) {
 	acmeMu.Lock()
 	defer acmeMu.Unlock()
 
@@ -393,7 +429,7 @@ func (b *LocalBackend) getCertPEM(ctx context.Context, cs certStore, logf logger
 	if p, err := getCertPEMCached(cs, domain, now); err == nil {
 		// shouldStartDomainRenewal caches its result so it's OK to call this
 		// frequently.
-		shouldRenew, err := b.shouldStartDomainRenewal(cs, domain, now, p)
+		shouldRenew, err := b.shouldStartDomainRenewal(cs, domain, now, p, minValidity)
 		if err != nil {
 			logf("error checking for certificate renewal: %v", err)
 		} else if !shouldRenew {

ipn/ipnlocal/local.go

@@ -1,6 +1,8 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// Package ipnlocal is the heart of the Tailscale node agent that controls
+// all the other misc pieces of the Tailscale node.
 package ipnlocal
 
 import (
@@ -23,6 +25,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"reflect"
 	"runtime"
 	"slices"
 	"sort"
@@ -389,18 +392,6 @@ func NewLocalBackend(logf logger.Logf, logID logid.PublicID, sys *tsd.System, lo
 		sds.SetDialer(dialer.SystemDial)
 	}
 
-	if sys.InitialConfig != nil {
-		p := pm.CurrentPrefs().AsStruct()
-		mp, err := sys.InitialConfig.Parsed.ToPrefs()
-		if err != nil {
-			return nil, err
-		}
-		p.ApplyEdits(&mp)
-		if err := pm.SetPrefs(p.View(), ipn.NetworkProfile{}); err != nil {
-			return nil, err
-		}
-	}
-
 	envknob.LogCurrent(logf)
 	osshare.SetFileSharingEnabled(false, logf)
 
@@ -415,7 +406,6 @@ func NewLocalBackend(logf logger.Logf, logID logid.PublicID, sys *tsd.System, lo
 		statsLogf:           logger.LogOnChange(logf, 5*time.Minute, clock.Now),
 		sys:                 sys,
 		health:              sys.HealthTracker(),
-		conf:                sys.InitialConfig,
 		e:                   e,
 		dialer:              dialer,
 		store:               store,
@@ -432,6 +422,12 @@ func NewLocalBackend(logf logger.Logf, logID logid.PublicID, sys *tsd.System, lo
 	}
 	mConn.SetNetInfoCallback(b.setNetInfo)
 
+	if sys.InitialConfig != nil {
+		if err := b.setConfigLocked(sys.InitialConfig); err != nil {
+			return nil, err
+		}
+	}
+
 	netMon := sys.NetMon.Get()
 	b.sockstatLogger, err = sockstatlog.NewLogger(logpolicy.LogsDir(logf), logf, logID, netMon, sys.HealthTracker())
 	if err != nil {
@@ -614,11 +610,50 @@ func (b *LocalBackend) ReloadConfig() (ok bool, err error) {
 	if err != nil {
 		return false, err
 	}
-	b.conf = conf
-	// TODO(bradfitz): apply things
+	if err := b.setConfigLocked(conf); err != nil {
+		return false, fmt.Errorf("error setting config: %w", err)
+	}
+
 	return true, nil
 }
 
+func (b *LocalBackend) setConfigLocked(conf *conffile.Config) error {
+
+	// TODO(irbekrm): notify the relevant components to consume any prefs
+	// updates. Currently only initial configfile settings are applied
+	// immediately.
+	p := b.pm.CurrentPrefs().AsStruct()
+	mp, err := conf.Parsed.ToPrefs()
+	if err != nil {
+		return fmt.Errorf("error parsing config to prefs: %w", err)
+	}
+	p.ApplyEdits(&mp)
+	if err := b.pm.SetPrefs(p.View(), ipn.NetworkProfile{}); err != nil {
+		return err
+	}
+
+	defer func() {
+		b.conf = conf
+	}()
+
+	if conf.Parsed.StaticEndpoints == nil && (b.conf == nil || b.conf.Parsed.StaticEndpoints == nil) {
+		return nil
+	}
+
+	// Ensure that magicsock conn has the up to date static wireguard
+	// endpoints. Setting the endpoints here triggers an asynchronous update
+	// of the node's advertised endpoints.
+	if b.conf == nil && len(conf.Parsed.StaticEndpoints) != 0 || !reflect.DeepEqual(conf.Parsed.StaticEndpoints, b.conf.Parsed.StaticEndpoints) {
+		ms, ok := b.sys.MagicSock.GetOK()
+		if !ok {
+			b.logf("[unexpected] ReloadConfig: MagicSock not set")
+		} else {
+			ms.SetStaticEndpoints(views.SliceOf(conf.Parsed.StaticEndpoints))
+		}
+	}
+	return nil
+}
+
 var assumeNetworkUpdateForTest = envknob.RegisterBool("TS_ASSUME_NETWORK_UP_FOR_TEST")
 
 // pauseOrResumeControlClientLocked pauses b.cc if there is no network available
@@ -728,7 +763,9 @@ func (b *LocalBackend) Shutdown() {
 	b.webClientShutdown()
 
 	if b.sockstatLogger != nil {
-		b.sockstatLogger.Shutdown()
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		b.sockstatLogger.Shutdown(ctx)
 	}
 	if b.peerAPIServer != nil {
 		b.peerAPIServer.taildrop.Shutdown()
@@ -1189,7 +1226,13 @@ func (b *LocalBackend) SetControlClientStatus(c controlclient.Client, st control
 
 	prefsChanged := false
 	prefs := b.pm.CurrentPrefs().AsStruct()
-	netMap := b.netMap
+	oldNetMap := b.netMap
+	curNetMap := st.NetMap
+	if curNetMap == nil {
+		// The status didn't include a netmap update, so the old one is still
+		// current.
+		curNetMap = oldNetMap
+	}
 
 	if prefs.ControlURL == "" {
 		// Once we get a message from the control plane, set
@@ -1220,7 +1263,14 @@ func (b *LocalBackend) SetControlClientStatus(c controlclient.Client, st control
 		prefs.WantRunning = true
 		prefs.LoggedOut = false
 	}
-	if setExitNodeID(prefs, st.NetMap, b.lastSuggestedExitNode) {
+	if shouldAutoExitNode() {
+		// Re-evaluate exit node suggestion in case circumstances have changed.
+		_, err := b.suggestExitNodeLocked(curNetMap)
+		if err != nil && !errors.Is(err, ErrNoPreferredDERP) {
+			b.logf("SetControlClientStatus failed to select auto exit node: %v", err)
+		}
+	}
+	if setExitNodeID(prefs, curNetMap, b.lastSuggestedExitNode) {
 		prefsChanged = true
 	}
 	if applySysPolicy(prefs) {
@@ -1237,8 +1287,8 @@ func (b *LocalBackend) SetControlClientStatus(c controlclient.Client, st control
 	if prefsChanged {
 		// Prefs will be written out if stale; this is not safe unless locked or cloned.
 		if err := b.pm.SetPrefs(prefs.View(), ipn.NetworkProfile{
-			MagicDNSName: st.NetMap.MagicDNSSuffix(),
-			DomainName:   st.NetMap.DomainName(),
+			MagicDNSName: curNetMap.MagicDNSSuffix(),
+			DomainName:   curNetMap.DomainName(),
 		}); err != nil {
 			b.logf("Failed to save new controlclient state: %v", err)
 		}
@@ -1305,8 +1355,8 @@ func (b *LocalBackend) SetControlClientStatus(c controlclient.Client, st control
 			b.send(ipn.Notify{ErrMessage: &msg, Prefs: &p})
 			return
 		}
-		if netMap != nil {
-			diff := st.NetMap.ConciseDiffFrom(netMap)
+		if oldNetMap != nil {
+			diff := st.NetMap.ConciseDiffFrom(oldNetMap)
 			if strings.TrimSpace(diff) == "" {
 				b.logf("[v1] netmap diff: (none)")
 			} else {
@@ -4865,8 +4915,32 @@ func (b *LocalBackend) Logout(ctx context.Context) error {
 func (b *LocalBackend) setNetInfo(ni *tailcfg.NetInfo) {
 	b.mu.Lock()
 	cc := b.cc
-	refresh := b.refreshAutoExitNode
-	b.refreshAutoExitNode = false
+	var refresh bool
+	if b.MagicConn().DERPs() > 0 || testenv.InTest() {
+		// When b.refreshAutoExitNode is set, we recently observed a link change
+		// that indicates we have switched networks. After switching networks,
+		// the previously selected automatic exit node is no longer as likely
+		// to be a good choice and connectivity will already be broken due to
+		// the network switch. Therefore, it is a good time to switch to a new
+		// exit node because the network is already disrupted.
+		//
+		// Unfortunately, at the time of the link change, no information is
+		// known about the new network's latency or location, so the necessary
+		// details are not available to make a new choice. Instead, it sets
+		// b.refreshAutoExitNode to signal that a new decision should be made
+		// when we have an updated netcheck report. ni is that updated report.
+		//
+		// However, during testing we observed that often the first ni is
+		// inconclusive because it was running during the link change or the
+		// link was otherwise not stable yet. b.MagicConn().updateEndpoints()
+		// can detect when the netcheck failed and trigger a rebind, but the
+		// required information is not available here, and moderate additional
+		// plumbing is required to pass that in. Instead, checking for an active
+		// DERP link offers an easy approximation. We will continue to refine
+		// this over time.
+		refresh = b.refreshAutoExitNode
+		b.refreshAutoExitNode = false
+	}
 	b.mu.Unlock()
 
 	if cc == nil {
@@ -4889,7 +4963,7 @@ func (b *LocalBackend) setAutoExitNodeIDLockedOnEntry(unlock unlockOnce) {
 		return
 	}
 	prefsClone := prefs.AsStruct()
-	newSuggestion, err := b.suggestExitNodeLocked()
+	newSuggestion, err := b.suggestExitNodeLocked(nil)
 	if err != nil {
 		b.logf("setAutoExitNodeID: %v", err)
 		return
@@ -6571,7 +6645,6 @@ func mayDeref[T any](p *T) (v T) {
 }
 
 var ErrNoPreferredDERP = errors.New("no preferred DERP, try again later")
-var ErrCannotSuggestExitNode = errors.New("unable to suggest an exit node, try again later")
 
 // suggestExitNodeLocked computes a suggestion based on the current netmap and last netcheck report. If
 // there are multiple equally good options, one is selected at random, so the result is not stable. To be
@@ -6580,10 +6653,17 @@ var ErrCannotSuggestExitNode = errors.New("unable to suggest an exit node, try a
 // Currently, peers with a DERP home are preferred over those without (typically this means Mullvad).
 // Peers are selected based on having a DERP home that is the lowest latency to this device. For peers
 // without a DERP home, we look for geographic proximity to this device's DERP home.
+//
+// netMap is an optional netmap to use that overrides b.netMap (needed for SetControlClientStatus before b.netMap is updated).
+// If netMap is nil, then b.netMap is used.
+//
 // b.mu.lock() must be held.
-func (b *LocalBackend) suggestExitNodeLocked() (response apitype.ExitNodeSuggestionResponse, err error) {
+func (b *LocalBackend) suggestExitNodeLocked(netMap *netmap.NetworkMap) (response apitype.ExitNodeSuggestionResponse, err error) {
+	// netMap is an optional netmap to use that overrides b.netMap (needed for SetControlClientStatus before b.netMap is updated). If netMap is nil, then b.netMap is used.
+	if netMap == nil {
+		netMap = b.netMap
+	}
 	lastReport := b.MagicConn().GetLastNetcheckReport(b.ctx)
-	netMap := b.netMap
 	prevSuggestion := b.lastSuggestedExitNode
 
 	res, err := suggestExitNode(lastReport, netMap, prevSuggestion, randomRegion, randomNode, getAllowedSuggestions())
@@ -6597,7 +6677,7 @@ func (b *LocalBackend) suggestExitNodeLocked() (response apitype.ExitNodeSuggest
 func (b *LocalBackend) SuggestExitNode() (response apitype.ExitNodeSuggestionResponse, err error) {
 	b.mu.Lock()
 	defer b.mu.Unlock()
-	return b.suggestExitNodeLocked()
+	return b.suggestExitNodeLocked(nil)
 }
 
 // selectRegionFunc returns a DERP region from the slice of candidate regions.

ipn/ipnlocal/local_test.go

@@ -2119,6 +2119,72 @@ func TestAutoExitNodeSetNetInfoCallback(t *testing.T) {
 	}
 }
 
+func TestSetControlClientStatusAutoExitNode(t *testing.T) {
+	peer1 := makePeer(1, withCap(26), withSuggest(), withExitRoutes(), withNodeKey())
+	peer2 := makePeer(2, withCap(26), withSuggest(), withExitRoutes(), withNodeKey())
+	derpMap := &tailcfg.DERPMap{
+		Regions: map[int]*tailcfg.DERPRegion{
+			1: {
+				Nodes: []*tailcfg.DERPNode{
+					{
+						Name:     "t1",
+						RegionID: 1,
+					},
+				},
+			},
+			2: {
+				Nodes: []*tailcfg.DERPNode{
+					{
+						Name:     "t2",
+						RegionID: 2,
+					},
+				},
+			},
+		},
+	}
+	report := &netcheck.Report{
+		RegionLatency: map[int]time.Duration{
+			1: 10 * time.Millisecond,
+			2: 5 * time.Millisecond,
+			3: 30 * time.Millisecond,
+		},
+		PreferredDERP: 1,
+	}
+	nm := &netmap.NetworkMap{
+		Peers: []tailcfg.NodeView{
+			peer1,
+			peer2,
+		},
+		DERPMap: derpMap,
+	}
+	b := newTestLocalBackend(t)
+	msh := &mockSyspolicyHandler{
+		t: t,
+		stringPolicies: map[syspolicy.Key]*string{
+			syspolicy.ExitNodeID: ptr.To("auto:any"),
+		},
+	}
+	syspolicy.SetHandlerForTest(t, msh)
+	b.netMap = nm
+	b.lastSuggestedExitNode = peer1.StableID()
+	b.sys.MagicSock.Get().SetLastNetcheckReportForTest(b.ctx, report)
+	b.SetPrefsForTest(b.pm.CurrentPrefs().AsStruct())
+	firstExitNode := b.Prefs().ExitNodeID()
+	newPeer1 := makePeer(1, withCap(26), withSuggest(), withExitRoutes(), withOnline(false), withNodeKey())
+	updatedNetmap := &netmap.NetworkMap{
+		Peers: []tailcfg.NodeView{
+			newPeer1,
+			peer2,
+		},
+		DERPMap: derpMap,
+	}
+	b.SetControlClientStatus(b.cc, controlclient.Status{NetMap: updatedNetmap})
+	lastExitNode := b.Prefs().ExitNodeID()
+	if firstExitNode == lastExitNode {
+		t.Errorf("did not switch exit nodes despite auto exit node going offline")
+	}
+}
+
 func TestApplySysPolicy(t *testing.T) {
 	tests := []struct {
 		name           string
@@ -3036,6 +3102,18 @@ func withCap(version tailcfg.CapabilityVersion) peerOptFunc {
 	}
 }
 
+func withOnline(isOnline bool) peerOptFunc {
+	return func(n *tailcfg.Node) {
+		n.Online = &isOnline
+	}
+}
+
+func withNodeKey() peerOptFunc {
+	return func(n *tailcfg.Node) {
+		n.Key = key.NewNode().Public()
+	}
+}
+
 func deterministicRegionForTest(t testing.TB, want views.Slice[int], use int) selectRegionFunc {
 	t.Helper()
 

ipn/ipnserver/server.go

@@ -1,6 +1,8 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// Package ipnserver runs the LocalAPI HTTP server that communicates
+// with the LocalBackend.
 package ipnserver
 
 import (

ipn/localapi/cert.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"net/http"
 	"strings"
+	"time"
 
 	"tailscale.com/ipn/ipnlocal"
 )
@@ -23,7 +24,16 @@ func (h *Handler) serveCert(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "internal handler config wired wrong", 500)
 		return
 	}
-	pair, err := h.b.GetCertPEM(r.Context(), domain)
+	var minValidity time.Duration
+	if minValidityStr := r.URL.Query().Get("min_validity"); minValidityStr != "" {
+		var err error
+		minValidity, err = time.ParseDuration(minValidityStr)
+		if err != nil {
+			http.Error(w, fmt.Sprintf("invalid validity parameter: %v", err), http.StatusBadRequest)
+			return
+		}
+	}
+	pair, err := h.b.GetCertPEMWithValidity(r.Context(), domain, minValidity)
 	if err != nil {
 		// TODO(bradfitz): 500 is a little lazy here. The errors returned from
 		// GetCertPEM (and everywhere) should carry info info to get whether

ipn/prefs.go

@@ -810,7 +810,7 @@ func exitNodeIPOfArg(s string, st *ipnstate.Status) (ip netip.Addr, err error) {
 	match := 0
 	for _, ps := range st.Peer {
 		baseName := dnsname.TrimSuffix(ps.DNSName, st.MagicDNSSuffix)
-		if !strings.EqualFold(s, baseName) {
+		if !strings.EqualFold(s, baseName) && !strings.EqualFold(s, ps.DNSName) {
 			continue
 		}
 		match++

ipn/prefs_test.go

@@ -914,6 +914,21 @@ func TestExitNodeIPOfArg(t *testing.T) {
 			},
 			want: mustIP("1.0.0.2"),
 		},
+		{
+			name: "name_fqdn",
+			arg:  "skippy.foo.",
+			st: &ipnstate.Status{
+				MagicDNSSuffix: ".foo",
+				Peer: map[key.NodePublic]*ipnstate.PeerStatus{
+					key.NewNode().Public(): {
+						DNSName:        "skippy.foo.",
+						TailscaleIPs:   []netip.Addr{mustIP("1.0.0.2")},
+						ExitNodeOption: true,
+					},
+				},
+			},
+			want: mustIP("1.0.0.2"),
+		},
 		{
 			name: "name_not_exit",
 			arg:  "skippy",
@@ -928,6 +943,20 @@ func TestExitNodeIPOfArg(t *testing.T) {
 			},
 			wantErr: `node "skippy" is not advertising an exit node`,
 		},
+		{
+			name: "name_wrong_fqdn",
+			arg:  "skippy.bar.",
+			st: &ipnstate.Status{
+				MagicDNSSuffix: ".foo",
+				Peer: map[key.NodePublic]*ipnstate.PeerStatus{
+					key.NewNode().Public(): {
+						DNSName:      "skippy.foo.",
+						TailscaleIPs: []netip.Addr{mustIP("1.0.0.2")},
+					},
+				},
+			},
+			wantErr: `invalid value "skippy.bar." for --exit-node; must be IP or unique node name`,
+		},
 		{
 			name: "ambiguous",
 			arg:  "skippy",

ipn/store/kubestore/store_kube.go

@@ -2,7 +2,6 @@
 // SPDX-License-Identifier: BSD-3-Clause
 
 // Package kubestore contains an ipn.StateStore implementation using Kubernetes Secrets.
-
 package kubestore
 
 import (

k8s-operator/apis/doc.go

@@ -3,6 +3,7 @@
 
 //go:build !plan9
 
+// Package apis contains a constant to name the Tailscale Kubernetes Operator's schema group.
 package apis
 
 const GroupName = "tailscale.com"

k8s-operator/utils.go

@@ -3,6 +3,7 @@
 
 //go:build !plan9
 
+// Package kube contains types and utilities for the Tailscale Kubernetes Operator.
 package kube
 
 import (

kube/fake_client.go

@@ -1,9 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-// Package kube provides a client to interact with Kubernetes.
-// This package is Tailscale-internal and not meant for external consumption.
-// Further, the API should not be considered stable.
 package kube
 
 import (

kube/grants.go

@@ -1,9 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-// Package kube provides a client to interact with Kubernetes.
-// This package is Tailscale-internal and not meant for external consumption.
-// Further, the API should not be considered stable.
 package kube
 
 import "net/netip"

licenses/android.md

@@ -29,7 +29,7 @@ Client][].  See also the dependencies in the [Tailscale CLI][].
  - [github.com/coreos/go-iptables/iptables](https://pkg.go.dev/github.com/coreos/go-iptables/iptables) ([Apache-2.0](https://github.com/coreos/go-iptables/blob/65c67c9f46e6/LICENSE))
  - [github.com/djherbis/times](https://pkg.go.dev/github.com/djherbis/times) ([MIT](https://github.com/djherbis/times/blob/v1.6.0/LICENSE))
  - [github.com/fxamacker/cbor/v2](https://pkg.go.dev/github.com/fxamacker/cbor/v2) ([MIT](https://github.com/fxamacker/cbor/blob/v2.6.0/LICENSE))
- - [github.com/gaissmai/bart](https://pkg.go.dev/github.com/gaissmai/bart) ([MIT](https://github.com/gaissmai/bart/blob/v0.4.1/LICENSE))
+ - [github.com/gaissmai/bart](https://pkg.go.dev/github.com/gaissmai/bart) ([MIT](https://github.com/gaissmai/bart/blob/v0.11.1/LICENSE))
  - [github.com/go-json-experiment/json](https://pkg.go.dev/github.com/go-json-experiment/json) ([BSD-3-Clause](https://github.com/go-json-experiment/json/blob/2e55bd4e08b0/LICENSE))
  - [github.com/godbus/dbus/v5](https://pkg.go.dev/github.com/godbus/dbus/v5) ([BSD-2-Clause](https://github.com/godbus/dbus/blob/76236955d466/LICENSE))
  - [github.com/golang/groupcache/lru](https://pkg.go.dev/github.com/golang/groupcache/lru) ([Apache-2.0](https://github.com/golang/groupcache/blob/41bb18bfe9da/LICENSE))
@@ -60,7 +60,7 @@ Client][].  See also the dependencies in the [Tailscale CLI][].
  - [github.com/tailscale/netlink](https://pkg.go.dev/github.com/tailscale/netlink) ([Apache-2.0](https://github.com/tailscale/netlink/blob/cabfb018fe85/LICENSE))
  - [github.com/tailscale/peercred](https://pkg.go.dev/github.com/tailscale/peercred) ([BSD-3-Clause](https://github.com/tailscale/peercred/blob/b535050b2aa4/LICENSE))
  - [github.com/tailscale/tailscale-android/libtailscale](https://pkg.go.dev/github.com/tailscale/tailscale-android/libtailscale) ([BSD-3-Clause](https://github.com/tailscale/tailscale-android/blob/HEAD/LICENSE))
- - [github.com/tailscale/wireguard-go](https://pkg.go.dev/github.com/tailscale/wireguard-go) ([MIT](https://github.com/tailscale/wireguard-go/blob/03c5a0ccf754/LICENSE))
+ - [github.com/tailscale/wireguard-go](https://pkg.go.dev/github.com/tailscale/wireguard-go) ([MIT](https://github.com/tailscale/wireguard-go/blob/2f5d148bcfe1/LICENSE))
  - [github.com/tailscale/xnet/webdav](https://pkg.go.dev/github.com/tailscale/xnet/webdav) ([BSD-3-Clause](https://github.com/tailscale/xnet/blob/62b9a7c569f9/LICENSE))
  - [github.com/tcnksm/go-httpstat](https://pkg.go.dev/github.com/tcnksm/go-httpstat) ([MIT](https://github.com/tcnksm/go-httpstat/blob/v0.2.0/LICENSE))
  - [github.com/u-root/uio](https://pkg.go.dev/github.com/u-root/uio) ([BSD-3-Clause](https://github.com/u-root/uio/blob/a3c409a6018e/LICENSE))

licenses/apple.md

@@ -33,7 +33,7 @@ See also the dependencies in the [Tailscale CLI][].
  - [github.com/digitalocean/go-smbios/smbios](https://pkg.go.dev/github.com/digitalocean/go-smbios/smbios) ([Apache-2.0](https://github.com/digitalocean/go-smbios/blob/390a4f403a8e/LICENSE.md))
  - [github.com/djherbis/times](https://pkg.go.dev/github.com/djherbis/times) ([MIT](https://github.com/djherbis/times/blob/v1.6.0/LICENSE))
  - [github.com/fxamacker/cbor/v2](https://pkg.go.dev/github.com/fxamacker/cbor/v2) ([MIT](https://github.com/fxamacker/cbor/blob/v2.6.0/LICENSE))
- - [github.com/gaissmai/bart](https://pkg.go.dev/github.com/gaissmai/bart) ([MIT](https://github.com/gaissmai/bart/blob/v0.4.1/LICENSE))
+ - [github.com/gaissmai/bart](https://pkg.go.dev/github.com/gaissmai/bart) ([MIT](https://github.com/gaissmai/bart/blob/v0.11.1/LICENSE))
  - [github.com/go-json-experiment/json](https://pkg.go.dev/github.com/go-json-experiment/json) ([BSD-3-Clause](https://github.com/go-json-experiment/json/blob/2e55bd4e08b0/LICENSE))
  - [github.com/godbus/dbus/v5](https://pkg.go.dev/github.com/godbus/dbus/v5) ([BSD-2-Clause](https://github.com/godbus/dbus/blob/76236955d466/LICENSE))
  - [github.com/golang/groupcache/lru](https://pkg.go.dev/github.com/golang/groupcache/lru) ([Apache-2.0](https://github.com/golang/groupcache/blob/41bb18bfe9da/LICENSE))
@@ -47,9 +47,9 @@ See also the dependencies in the [Tailscale CLI][].
  - [github.com/jmespath/go-jmespath](https://pkg.go.dev/github.com/jmespath/go-jmespath) ([Apache-2.0](https://github.com/jmespath/go-jmespath/blob/v0.4.0/LICENSE))
  - [github.com/josharian/native](https://pkg.go.dev/github.com/josharian/native) ([MIT](https://github.com/josharian/native/blob/5c7d0dd6ab86/license))
  - [github.com/jsimonetti/rtnetlink](https://pkg.go.dev/github.com/jsimonetti/rtnetlink) ([MIT](https://github.com/jsimonetti/rtnetlink/blob/v1.4.1/LICENSE.md))
- - [github.com/klauspost/compress](https://pkg.go.dev/github.com/klauspost/compress) ([Apache-2.0](https://github.com/klauspost/compress/blob/v1.17.7/LICENSE))
- - [github.com/klauspost/compress/internal/snapref](https://pkg.go.dev/github.com/klauspost/compress/internal/snapref) ([BSD-3-Clause](https://github.com/klauspost/compress/blob/v1.17.7/internal/snapref/LICENSE))
- - [github.com/klauspost/compress/zstd/internal/xxhash](https://pkg.go.dev/github.com/klauspost/compress/zstd/internal/xxhash) ([MIT](https://github.com/klauspost/compress/blob/v1.17.7/zstd/internal/xxhash/LICENSE.txt))
+ - [github.com/klauspost/compress](https://pkg.go.dev/github.com/klauspost/compress) ([Apache-2.0](https://github.com/klauspost/compress/blob/v1.17.8/LICENSE))
+ - [github.com/klauspost/compress/internal/snapref](https://pkg.go.dev/github.com/klauspost/compress/internal/snapref) ([BSD-3-Clause](https://github.com/klauspost/compress/blob/v1.17.8/internal/snapref/LICENSE))
+ - [github.com/klauspost/compress/zstd/internal/xxhash](https://pkg.go.dev/github.com/klauspost/compress/zstd/internal/xxhash) ([MIT](https://github.com/klauspost/compress/blob/v1.17.8/zstd/internal/xxhash/LICENSE.txt))
  - [github.com/kortschak/wol](https://pkg.go.dev/github.com/kortschak/wol) ([BSD-3-Clause](https://github.com/kortschak/wol/blob/da482cc4850a/LICENSE))
  - [github.com/mdlayher/genetlink](https://pkg.go.dev/github.com/mdlayher/genetlink) ([MIT](https://github.com/mdlayher/genetlink/blob/v1.3.2/LICENSE.md))
  - [github.com/mdlayher/netlink](https://pkg.go.dev/github.com/mdlayher/netlink) ([MIT](https://github.com/mdlayher/netlink/blob/v1.7.2/LICENSE.md))
@@ -65,7 +65,7 @@ See also the dependencies in the [Tailscale CLI][].
  - [github.com/tailscale/hujson](https://pkg.go.dev/github.com/tailscale/hujson) ([BSD-3-Clause](https://github.com/tailscale/hujson/blob/20486734a56a/LICENSE))
  - [github.com/tailscale/netlink](https://pkg.go.dev/github.com/tailscale/netlink) ([Apache-2.0](https://github.com/tailscale/netlink/blob/cabfb018fe85/LICENSE))
  - [github.com/tailscale/peercred](https://pkg.go.dev/github.com/tailscale/peercred) ([BSD-3-Clause](https://github.com/tailscale/peercred/blob/b535050b2aa4/LICENSE))
- - [github.com/tailscale/wireguard-go](https://pkg.go.dev/github.com/tailscale/wireguard-go) ([MIT](https://github.com/tailscale/wireguard-go/blob/cfa45674af86/LICENSE))
+ - [github.com/tailscale/wireguard-go](https://pkg.go.dev/github.com/tailscale/wireguard-go) ([MIT](https://github.com/tailscale/wireguard-go/blob/2f5d148bcfe1/LICENSE))
  - [github.com/tailscale/xnet/webdav](https://pkg.go.dev/github.com/tailscale/xnet/webdav) ([BSD-3-Clause](https://github.com/tailscale/xnet/blob/62b9a7c569f9/LICENSE))
  - [github.com/tcnksm/go-httpstat](https://pkg.go.dev/github.com/tcnksm/go-httpstat) ([MIT](https://github.com/tcnksm/go-httpstat/blob/v0.2.0/LICENSE))
  - [github.com/u-root/uio](https://pkg.go.dev/github.com/u-root/uio) ([BSD-3-Clause](https://github.com/u-root/uio/blob/a3c409a6018e/LICENSE))
@@ -74,12 +74,12 @@ See also the dependencies in the [Tailscale CLI][].
  - [github.com/x448/float16](https://pkg.go.dev/github.com/x448/float16) ([MIT](https://github.com/x448/float16/blob/v0.8.4/LICENSE))
  - [go4.org/mem](https://pkg.go.dev/go4.org/mem) ([Apache-2.0](https://github.com/go4org/mem/blob/ae6ca9944745/LICENSE))
  - [go4.org/netipx](https://pkg.go.dev/go4.org/netipx) ([BSD-3-Clause](https://github.com/go4org/netipx/blob/fdeea329fbba/LICENSE))
- - [golang.org/x/crypto](https://pkg.go.dev/golang.org/x/crypto) ([BSD-3-Clause](https://cs.opensource.google/go/x/crypto/+/v0.24.0:LICENSE))
+ - [golang.org/x/crypto](https://pkg.go.dev/golang.org/x/crypto) ([BSD-3-Clause](https://cs.opensource.google/go/x/crypto/+/v0.25.0:LICENSE))
  - [golang.org/x/exp](https://pkg.go.dev/golang.org/x/exp) ([BSD-3-Clause](https://cs.opensource.google/go/x/exp/+/fe59bbe5:LICENSE))
- - [golang.org/x/net](https://pkg.go.dev/golang.org/x/net) ([BSD-3-Clause](https://cs.opensource.google/go/x/net/+/v0.26.0:LICENSE))
+ - [golang.org/x/net](https://pkg.go.dev/golang.org/x/net) ([BSD-3-Clause](https://cs.opensource.google/go/x/net/+/v0.27.0:LICENSE))
  - [golang.org/x/sync](https://pkg.go.dev/golang.org/x/sync) ([BSD-3-Clause](https://cs.opensource.google/go/x/sync/+/v0.7.0:LICENSE))
- - [golang.org/x/sys](https://pkg.go.dev/golang.org/x/sys) ([BSD-3-Clause](https://cs.opensource.google/go/x/sys/+/v0.21.0:LICENSE))
- - [golang.org/x/term](https://pkg.go.dev/golang.org/x/term) ([BSD-3-Clause](https://cs.opensource.google/go/x/term/+/v0.21.0:LICENSE))
+ - [golang.org/x/sys](https://pkg.go.dev/golang.org/x/sys) ([BSD-3-Clause](https://cs.opensource.google/go/x/sys/+/v0.22.0:LICENSE))
+ - [golang.org/x/term](https://pkg.go.dev/golang.org/x/term) ([BSD-3-Clause](https://cs.opensource.google/go/x/term/+/v0.22.0:LICENSE))
  - [golang.org/x/text](https://pkg.go.dev/golang.org/x/text) ([BSD-3-Clause](https://cs.opensource.google/go/x/text/+/v0.16.0:LICENSE))
  - [golang.org/x/time/rate](https://pkg.go.dev/golang.org/x/time/rate) ([BSD-3-Clause](https://cs.opensource.google/go/x/time/+/v0.5.0:LICENSE))
  - [gvisor.dev/gvisor/pkg](https://pkg.go.dev/gvisor.dev/gvisor/pkg) ([Apache-2.0](https://github.com/google/gvisor/blob/ee1e1f6070e3/LICENSE))

licenses/tailscale.md

@@ -40,7 +40,7 @@ Some packages may only be included on certain architectures or operating systems
  - [github.com/digitalocean/go-smbios/smbios](https://pkg.go.dev/github.com/digitalocean/go-smbios/smbios) ([Apache-2.0](https://github.com/digitalocean/go-smbios/blob/390a4f403a8e/LICENSE.md))
  - [github.com/djherbis/times](https://pkg.go.dev/github.com/djherbis/times) ([MIT](https://github.com/djherbis/times/blob/v1.6.0/LICENSE))
  - [github.com/fxamacker/cbor/v2](https://pkg.go.dev/github.com/fxamacker/cbor/v2) ([MIT](https://github.com/fxamacker/cbor/blob/v2.6.0/LICENSE))
- - [github.com/gaissmai/bart](https://pkg.go.dev/github.com/gaissmai/bart) ([MIT](https://github.com/gaissmai/bart/blob/v0.4.1/LICENSE))
+ - [github.com/gaissmai/bart](https://pkg.go.dev/github.com/gaissmai/bart) ([MIT](https://github.com/gaissmai/bart/blob/v0.11.1/LICENSE))
  - [github.com/go-json-experiment/json](https://pkg.go.dev/github.com/go-json-experiment/json) ([BSD-3-Clause](https://github.com/go-json-experiment/json/blob/2e55bd4e08b0/LICENSE))
  - [github.com/go-ole/go-ole](https://pkg.go.dev/github.com/go-ole/go-ole) ([MIT](https://github.com/go-ole/go-ole/blob/v1.3.0/LICENSE))
  - [github.com/godbus/dbus/v5](https://pkg.go.dev/github.com/godbus/dbus/v5) ([BSD-2-Clause](https://github.com/godbus/dbus/blob/76236955d466/LICENSE))
@@ -84,7 +84,7 @@ Some packages may only be included on certain architectures or operating systems
  - [github.com/tailscale/peercred](https://pkg.go.dev/github.com/tailscale/peercred) ([BSD-3-Clause](https://github.com/tailscale/peercred/blob/b535050b2aa4/LICENSE))
  - [github.com/tailscale/web-client-prebuilt](https://pkg.go.dev/github.com/tailscale/web-client-prebuilt) ([BSD-3-Clause](https://github.com/tailscale/web-client-prebuilt/blob/5db17b287bf1/LICENSE))
  - [github.com/tailscale/wf](https://pkg.go.dev/github.com/tailscale/wf) ([BSD-3-Clause](https://github.com/tailscale/wf/blob/6fbb0a674ee6/LICENSE))
- - [github.com/tailscale/wireguard-go](https://pkg.go.dev/github.com/tailscale/wireguard-go) ([MIT](https://github.com/tailscale/wireguard-go/blob/cfa45674af86/LICENSE))
+ - [github.com/tailscale/wireguard-go](https://pkg.go.dev/github.com/tailscale/wireguard-go) ([MIT](https://github.com/tailscale/wireguard-go/blob/2f5d148bcfe1/LICENSE))
  - [github.com/tailscale/xnet/webdav](https://pkg.go.dev/github.com/tailscale/xnet/webdav) ([BSD-3-Clause](https://github.com/tailscale/xnet/blob/62b9a7c569f9/LICENSE))
  - [github.com/tcnksm/go-httpstat](https://pkg.go.dev/github.com/tcnksm/go-httpstat) ([MIT](https://github.com/tcnksm/go-httpstat/blob/v0.2.0/LICENSE))
  - [github.com/toqueteos/webbrowser](https://pkg.go.dev/github.com/toqueteos/webbrowser) ([MIT](https://github.com/toqueteos/webbrowser/blob/v1.2.0/LICENSE.md))

licenses/windows.md

@@ -44,9 +44,9 @@ Windows][].  See also the dependencies in the [Tailscale CLI][].
  - [github.com/jmespath/go-jmespath](https://pkg.go.dev/github.com/jmespath/go-jmespath) ([Apache-2.0](https://github.com/jmespath/go-jmespath/blob/v0.4.0/LICENSE))
  - [github.com/josharian/native](https://pkg.go.dev/github.com/josharian/native) ([MIT](https://github.com/josharian/native/blob/5c7d0dd6ab86/license))
  - [github.com/jsimonetti/rtnetlink](https://pkg.go.dev/github.com/jsimonetti/rtnetlink) ([MIT](https://github.com/jsimonetti/rtnetlink/blob/v1.4.1/LICENSE.md))
- - [github.com/klauspost/compress](https://pkg.go.dev/github.com/klauspost/compress) ([Apache-2.0](https://github.com/klauspost/compress/blob/v1.17.7/LICENSE))
- - [github.com/klauspost/compress/internal/snapref](https://pkg.go.dev/github.com/klauspost/compress/internal/snapref) ([BSD-3-Clause](https://github.com/klauspost/compress/blob/v1.17.7/internal/snapref/LICENSE))
- - [github.com/klauspost/compress/zstd/internal/xxhash](https://pkg.go.dev/github.com/klauspost/compress/zstd/internal/xxhash) ([MIT](https://github.com/klauspost/compress/blob/v1.17.7/zstd/internal/xxhash/LICENSE.txt))
+ - [github.com/klauspost/compress](https://pkg.go.dev/github.com/klauspost/compress) ([Apache-2.0](https://github.com/klauspost/compress/blob/v1.17.8/LICENSE))
+ - [github.com/klauspost/compress/internal/snapref](https://pkg.go.dev/github.com/klauspost/compress/internal/snapref) ([BSD-3-Clause](https://github.com/klauspost/compress/blob/v1.17.8/internal/snapref/LICENSE))
+ - [github.com/klauspost/compress/zstd/internal/xxhash](https://pkg.go.dev/github.com/klauspost/compress/zstd/internal/xxhash) ([MIT](https://github.com/klauspost/compress/blob/v1.17.8/zstd/internal/xxhash/LICENSE.txt))
  - [github.com/mdlayher/netlink](https://pkg.go.dev/github.com/mdlayher/netlink) ([MIT](https://github.com/mdlayher/netlink/blob/v1.7.2/LICENSE.md))
  - [github.com/mdlayher/socket](https://pkg.go.dev/github.com/mdlayher/socket) ([MIT](https://github.com/mdlayher/socket/blob/v0.5.0/LICENSE.md))
  - [github.com/miekg/dns](https://pkg.go.dev/github.com/miekg/dns) ([BSD-3-Clause](https://github.com/miekg/dns/blob/v1.1.58/LICENSE))
@@ -66,14 +66,14 @@ Windows][].  See also the dependencies in the [Tailscale CLI][].
  - [github.com/x448/float16](https://pkg.go.dev/github.com/x448/float16) ([MIT](https://github.com/x448/float16/blob/v0.8.4/LICENSE))
  - [go4.org/mem](https://pkg.go.dev/go4.org/mem) ([Apache-2.0](https://github.com/go4org/mem/blob/ae6ca9944745/LICENSE))
  - [go4.org/netipx](https://pkg.go.dev/go4.org/netipx) ([BSD-3-Clause](https://github.com/go4org/netipx/blob/fdeea329fbba/LICENSE))
- - [golang.org/x/crypto](https://pkg.go.dev/golang.org/x/crypto) ([BSD-3-Clause](https://cs.opensource.google/go/x/crypto/+/v0.24.0:LICENSE))
+ - [golang.org/x/crypto](https://pkg.go.dev/golang.org/x/crypto) ([BSD-3-Clause](https://cs.opensource.google/go/x/crypto/+/v0.25.0:LICENSE))
  - [golang.org/x/exp/constraints](https://pkg.go.dev/golang.org/x/exp/constraints) ([BSD-3-Clause](https://cs.opensource.google/go/x/exp/+/fe59bbe5:LICENSE))
  - [golang.org/x/image/bmp](https://pkg.go.dev/golang.org/x/image/bmp) ([BSD-3-Clause](https://cs.opensource.google/go/x/image/+/v0.18.0:LICENSE))
  - [golang.org/x/mod](https://pkg.go.dev/golang.org/x/mod) ([BSD-3-Clause](https://cs.opensource.google/go/x/mod/+/v0.18.0:LICENSE))
- - [golang.org/x/net](https://pkg.go.dev/golang.org/x/net) ([BSD-3-Clause](https://cs.opensource.google/go/x/net/+/v0.26.0:LICENSE))
+ - [golang.org/x/net](https://pkg.go.dev/golang.org/x/net) ([BSD-3-Clause](https://cs.opensource.google/go/x/net/+/v0.27.0:LICENSE))
  - [golang.org/x/sync](https://pkg.go.dev/golang.org/x/sync) ([BSD-3-Clause](https://cs.opensource.google/go/x/sync/+/v0.7.0:LICENSE))
- - [golang.org/x/sys](https://pkg.go.dev/golang.org/x/sys) ([BSD-3-Clause](https://cs.opensource.google/go/x/sys/+/v0.21.0:LICENSE))
- - [golang.org/x/term](https://pkg.go.dev/golang.org/x/term) ([BSD-3-Clause](https://cs.opensource.google/go/x/term/+/v0.21.0:LICENSE))
+ - [golang.org/x/sys](https://pkg.go.dev/golang.org/x/sys) ([BSD-3-Clause](https://cs.opensource.google/go/x/sys/+/v0.22.0:LICENSE))
+ - [golang.org/x/term](https://pkg.go.dev/golang.org/x/term) ([BSD-3-Clause](https://cs.opensource.google/go/x/term/+/v0.22.0:LICENSE))
  - [golang.org/x/text](https://pkg.go.dev/golang.org/x/text) ([BSD-3-Clause](https://cs.opensource.google/go/x/text/+/v0.16.0:LICENSE))
  - [golang.zx2c4.com/wintun](https://pkg.go.dev/golang.zx2c4.com/wintun) ([MIT](https://git.zx2c4.com/wintun-go/tree/LICENSE?id=0fa3db229ce2))
  - [golang.zx2c4.com/wireguard/windows/tunnel/winipcfg](https://pkg.go.dev/golang.zx2c4.com/wireguard/windows/tunnel/winipcfg) ([MIT](https://git.zx2c4.com/wireguard-windows/tree/COPYING?h=v0.5.3))

log/sockstatlog/logger.go

@@ -242,12 +242,12 @@ func (l *Logger) Flush() {
 	l.logger.StartFlush()
 }
 
-func (l *Logger) Shutdown() {
+func (l *Logger) Shutdown(ctx context.Context) {
 	if l.cancelFn != nil {
 		l.cancelFn()
 	}
 	l.filch.Close()
-	l.logger.Shutdown(context.Background())
+	l.logger.Shutdown(ctx)
 
 	type closeIdler interface {
 		CloseIdleConnections()

log/sockstatlog/logger_test.go

@@ -4,6 +4,7 @@
 package sockstatlog
 
 import (
+	"context"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -28,7 +29,7 @@ func TestResourceCleanup(t *testing.T) {
 		t.Fatal(err)
 	}
 	lg.Write([]byte("hello"))
-	lg.Shutdown()
+	lg.Shutdown(context.Background())
 }
 
 func TestDelta(t *testing.T) {

logtail/example/logadopt/logadopt.go

@@ -1,6 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// Command logadopt is a CLI tool to adopt a machine into a logtail collection.
 package main
 
 import (

logtail/logtail.go

@@ -266,6 +266,7 @@ func (l *Logger) Shutdown(ctx context.Context) error {
 		case <-l.shutdownDone:
 		}
 		close(done)
+		l.httpc.CloseIdleConnections()
 	}()
 
 	l.shutdownStartMu.Lock()

net/dns/config.go

@@ -1,6 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+// Package dns contains code to configure and manage DNS settings.
 package dns
 
 import (

net/dns/manager_windows_test.go

@@ -17,6 +17,7 @@ import (
 	"golang.org/x/sys/windows/registry"
 	"tailscale.com/util/dnsname"
 	"tailscale.com/util/winutil"
+	"tailscale.com/util/winutil/gp"
 )
 
 const testGPRuleID = "{7B1B6151-84E6-41A3-8967-62F7F7B45687}"
@@ -51,7 +52,7 @@ func TestManagerWindowsGP(t *testing.T) {
 
 	// Make sure group policy is refreshed before this test exits but after we've
 	// cleaned everything else up.
-	defer procRefreshPolicyEx.Call(uintptr(1), uintptr(_RP_FORCE))
+	defer gp.RefreshMachinePolicy(true)
 
 	err := createFakeGPKey()
 	if err != nil {
@@ -129,7 +130,7 @@ func TestManagerWindowsGPCopy(t *testing.T) {
 		t.Fatalf("regWatcher.watch: %v\n", err)
 	}
 
-	err = testDoRefresh()
+	err = gp.RefreshMachinePolicy(true)
 	if err != nil {
 		t.Fatalf("testDoRefresh: %v\n", err)
 	}
@@ -153,7 +154,7 @@ func TestManagerWindowsGPCopy(t *testing.T) {
 		t.Fatalf("regWatcher.watch: %v\n", err)
 	}
 
-	err = testDoRefresh()
+	err = gp.RefreshMachinePolicy(true)
 	if err != nil {
 		t.Fatalf("testDoRefresh: %v\n", err)
 	}
@@ -186,8 +187,8 @@ func checkGPNotificationsWork(t *testing.T) {
 	}
 	defer trk.Close()
 
-	r, _, err := procRefreshPolicyEx.Call(uintptr(1), uintptr(_RP_FORCE))
-	if r == 0 {
+	err = gp.RefreshMachinePolicy(true)
+	if err != nil {
 		t.Fatalf("RefreshPolicyEx error: %v\n", err)
 	}
 
@@ -516,13 +517,11 @@ func genRandomSubdomains(t *testing.T, n int) []dnsname.FQDN {
 	return domains
 }
 
-func testDoRefresh() (err error) {
-	r, _, e := procRefreshPolicyEx.Call(uintptr(1), uintptr(_RP_FORCE))
-	if r == 0 {
-		err = e
-	}
-	return err
-}
+var (
+	libUserenv                   = windows.NewLazySystemDLL("userenv.dll")
+	procRegisterGPNotification   = libUserenv.NewProc("RegisterGPNotification")
+	procUnregisterGPNotification = libUserenv.NewProc("UnregisterGPNotification")
+)
 
 // gpNotificationTracker registers with the Windows policy engine and receives
 // notifications when policy refreshes occur.

net/dns/nrpt_windows.go

@@ -15,6 +15,7 @@ import (
 	"tailscale.com/util/dnsname"
 	"tailscale.com/util/set"
 	"tailscale.com/util/winutil"
+	"tailscale.com/util/winutil/gp"
 )
 
 const (
@@ -49,20 +50,11 @@ const (
 	nrptRuleFlagsName = `ConfigOptions`
 )
 
-var (
-	libUserenv                   = windows.NewLazySystemDLL("userenv.dll")
-	procRefreshPolicyEx          = libUserenv.NewProc("RefreshPolicyEx")
-	procRegisterGPNotification   = libUserenv.NewProc("RegisterGPNotification")
-	procUnregisterGPNotification = libUserenv.NewProc("UnregisterGPNotification")
-)
-
-const _RP_FORCE = 1 // Flag for RefreshPolicyEx
-
 // nrptRuleDatabase encapsulates access to the Windows Name Resolution Policy
 // Table (NRPT).
 type nrptRuleDatabase struct {
 	logf               logger.Logf
-	watcher            *gpNotificationWatcher
+	watcher            *gp.ChangeWatcher
 	isGPRefreshPending atomic.Bool
 	mu                 sync.Mutex // protects the fields below
 	ruleIDs            []string
@@ -303,12 +295,8 @@ func (db *nrptRuleDatabase) refreshLocked() {
 	// positives.
 	db.isGPRefreshPending.Store(true)
 
-	ok, _, err := procRefreshPolicyEx.Call(
-		uintptr(1), // Win32 TRUE: Refresh computer policy, not user policy.
-		uintptr(_RP_FORCE),
-	)
-	if ok == 0 {
-		db.logf("RefreshPolicyEx failed: %v", err)
+	if err := gp.RefreshMachinePolicy(true); err != nil {
+		db.logf("RefreshMachinePolicy failed: %v", err)
 		return
 	}
 
@@ -376,7 +364,7 @@ func (db *nrptRuleDatabase) watchForGPChanges() {
 		db.detectWriteAsGP()
 	}
 
-	watcher, err := newGPNotificationWatcher(watchHandler)
+	watcher, err := gp.NewChangeWatcher(gp.MachinePolicy, watchHandler)
 	if err != nil {
 		return
 	}
@@ -469,103 +457,3 @@ func (db *nrptRuleDatabase) Close() error {
 	db.watcher = nil
 	return err
 }
-
-type gpNotificationWatcher struct {
-	gpWaitEvents [2]windows.Handle
-	handler      func()
-	done         chan struct{}
-}
-
-// newGPNotificationWatcher creates an instance of gpNotificationWatcher that
-// invokes handler every time Windows notifies it of a group policy change.
-func newGPNotificationWatcher(handler func()) (*gpNotificationWatcher, error) {
-	var err error
-
-	// evtDone is signaled by (*gpNotificationWatcher).Close() to indicate that
-	// the doWatch goroutine should exit.
-	evtDone, err := windows.CreateEvent(nil, 0, 0, nil)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		if err != nil {
-			windows.CloseHandle(evtDone)
-		}
-	}()
-
-	// evtChanged is registered with the Windows policy engine to become
-	// signalled any time group policy has been refreshed.
-	evtChanged, err := windows.CreateEvent(nil, 0, 0, nil)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		if err != nil {
-			windows.CloseHandle(evtChanged)
-		}
-	}()
-
-	// Tell Windows to signal evtChanged whenever group policies are refreshed.
-	ok, _, e := procRegisterGPNotification.Call(
-		uintptr(evtChanged),
-		uintptr(1), // Win32 TRUE: We want to monitor computer policy changes, not user policy changes.
-	)
-	if ok == 0 {
-		err = e
-		return nil, err
-	}
-
-	result := &gpNotificationWatcher{
-		// Ordering of the event handles in gpWaitEvents is important:
-		// When calling windows.WaitForMultipleObjects and multiple objects are
-		// signalled simultaneously, it always returns the wait code for the
-		// lowest-indexed handle in its input array. evtDone is higher priority for
-		// us than evtChanged, so the former must be placed into the array ahead of
-		// the latter.
-		gpWaitEvents: [2]windows.Handle{
-			evtDone,
-			evtChanged,
-		},
-		handler: handler,
-		done:    make(chan struct{}),
-	}
-
-	go result.doWatch()
-
-	return result, nil
-}
-
-func (w *gpNotificationWatcher) doWatch() {
-	// The wait code corresponding to the event that is signalled when a group
-	// policy change occurs.
-	const expectedWaitCode = windows.WAIT_OBJECT_0 + 1
-	for {
-		if waitCode, _ := windows.WaitForMultipleObjects(w.gpWaitEvents[:], false, windows.INFINITE); waitCode != expectedWaitCode {
-			break
-		}
-		w.handler()
-	}
-	close(w.done)
-}
-
-func (w *gpNotificationWatcher) Close() error {
-	// Notify doWatch that we're done and it should exit.
-	if err := windows.SetEvent(w.gpWaitEvents[0]); err != nil {
-		return err
-	}
-
-	procUnregisterGPNotification.Call(uintptr(w.gpWaitEvents[1]))
-
-	// Wait for doWatch to complete.
-	<-w.done
-
-	// Now we may safely clean up all the things.
-	for i, evt := range w.gpWaitEvents {
-		windows.CloseHandle(evt)
-		w.gpWaitEvents[i] = 0
-	}
-
-	w.handler = nil
-
-	return nil
-}

net/dns/publicdns/publicdns.go

@@ -10,6 +10,7 @@ import (
 	"encoding/binary"
 	"encoding/hex"
 	"fmt"
+	"log"
 	"math/big"
 	"net/netip"
 	"sort"
@@ -122,6 +123,9 @@ func DoHIPsOfBase(dohBase string) []netip.Addr {
 		}
 	}
 	if pathStr, ok := strings.CutPrefix(dohBase, controlDBase); ok {
+		if i := strings.IndexFunc(pathStr, isSlashOrQuestionMark); i != -1 {
+			pathStr = pathStr[:i]
+		}
 		return []netip.Addr{
 			controlDv4One,
 			controlDv4Two,
@@ -318,7 +322,10 @@ func nextDNSv6Gen(ip netip.Addr, id []byte) netip.Addr {
 // e.g. https://dns.controld.com/hyq3ipr2ct
 func controlDv6Gen(ip netip.Addr, id string) netip.Addr {
 	b := make([]byte, 8)
-	decoded, _ := strconv.ParseUint(id, 36, 64)
+	decoded, err := strconv.ParseUint(id, 36, 64)
+	if err != nil {
+		log.Printf("controlDv6Gen: failed to parse id %q: %v", id, err)
+	}
 	binary.BigEndian.PutUint64(b, decoded)
 	a := ip.AsSlice()
 	copy(a[6:14], b)

net/dns/publicdns/publicdns_test.go

@@ -134,6 +134,15 @@ func TestDoHIPsOfBase(t *testing.T) {
 				"2606:1a40:1:ffff:ffff:ffff:ffff:0",
 			),
 		},
+		{
+			base: "https://dns.controld.com/hyq3ipr2ct/test-host-name",
+			want: ips(
+				"76.76.2.22",
+				"76.76.10.22",
+				"2606:1a40:0:6:7b5b:5949:35ad:0",
+				"2606:1a40:1:6:7b5b:5949:35ad:0",
+			),
+		},
 	}
 	for _, tt := range tests {
 		got := DoHIPsOfBase(tt.base)

net/ipset/ipset.go

@@ -22,7 +22,7 @@ func emptySet(ip netip.Addr) bool { return false }
 
 func bartLookup(t *bart.Table[struct{}]) func(netip.Addr) bool {
 	return func(ip netip.Addr) bool {
-		_, ok := t.Get(ip)
+		_, ok := t.Lookup(ip)
 		return ok
 	}
 }

net/netmon/state.go

@@ -1,7 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-// Package interfaces contains helpers for looking up system network interfaces.
 package netmon
 
 import (

net/netstat/netstat_windows.go

@@ -1,7 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-// Package netstat returns the local machine's network connection table.
 package netstat
 
 import (

net/netutil/ip_forward.go

@@ -1,7 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-// Package netutil contains misc shared networking code & types.
 package netutil
 
 import (

net/tsdial/tsdial.go

@@ -417,7 +417,7 @@ func (d *Dialer) UserDial(ctx context.Context, network, addr string) (net.Conn,
 	}
 
 	if routes := d.routes.Load(); routes != nil {
-		if isTailscaleRoute, _ := routes.Get(ipp.Addr()); isTailscaleRoute {
+		if isTailscaleRoute, _ := routes.Lookup(ipp.Addr()); isTailscaleRoute {
 			return d.getPeerDialer().DialContext(ctx, network, ipp.String())
 		}
 

net/tstun/wrap.go

@@ -1,8 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-// Package tstun provides a TUN struct implementing the tun.Device interface
-// with additional features as required by wgengine.
 package tstun
 
 import (
@@ -626,7 +624,7 @@ func (pc *peerConfigTable) mapDstIP(src, oldDst netip.Addr) netip.Addr {
 	// The 'dst' of the packet is the address for this local node. It could
 	// be a masquerade address that we told other nodes to use, or one of
 	// our local node's Addresses.
-	c, ok := pc.byIP.Get(src)
+	c, ok := pc.byIP.Lookup(src)
 	if !ok {
 		return oldDst
 	}
@@ -657,7 +655,7 @@ func (pc *peerConfigTable) selectSrcIP(oldSrc, dst netip.Addr) netip.Addr {
 	}
 
 	// Look up the configuration for the destination
-	c, ok := pc.byIP.Get(dst)
+	c, ok := pc.byIP.Lookup(dst)
 	if !ok {
 		return oldSrc
 	}
@@ -767,7 +765,7 @@ func (pc *peerConfigTable) inboundPacketIsJailed(p *packet.Parsed) bool {
 	if pc == nil {
 		return false
 	}
-	c, ok := pc.byIP.Get(p.Src.Addr())
+	c, ok := pc.byIP.Lookup(p.Src.Addr())
 	if !ok {
 		return false
 	}
@@ -778,14 +776,14 @@ func (pc *peerConfigTable) outboundPacketIsJailed(p *packet.Parsed) bool {
 	if pc == nil {
 		return false
 	}
-	c, ok := pc.byIP.Get(p.Dst.Addr())
+	c, ok := pc.byIP.Lookup(p.Dst.Addr())
 	if !ok {
 		return false
 	}
 	return c.jailed
 }
 
-// SetNetMap is called when a new NetworkMap is received.
+// SetWGConfig is called when a new NetworkMap is received.
 func (t *Wrapper) SetWGConfig(wcfg *wgcfg.Config) {
 	cfg := peerConfigTableFromWGConfig(wcfg)
 

pkgdoc_test.go

@@ -0,0 +1,75 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package tailscaleroot
+
+import (
+	"go/parser"
+	"go/token"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestPackageDocs(t *testing.T) {
+	switch runtime.GOOS {
+	case "darwin", "linux":
+		// Enough coverage for CI+devs.
+	default:
+		t.Skipf("skipping on %s", runtime.GOOS)
+	}
+
+	var goFiles []string
+	err := filepath.Walk(".", func(path string, fi os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if fi.Mode().IsRegular() && strings.HasSuffix(path, ".go") {
+			if strings.HasSuffix(path, "_test.go") {
+				return nil
+			}
+			goFiles = append(goFiles, path)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	byDir := map[string][]string{} // dir => files
+	for _, fileName := range goFiles {
+		fset := token.NewFileSet()
+		f, err := parser.ParseFile(fset, fileName, nil, parser.PackageClauseOnly|parser.ParseComments)
+		if err != nil {
+			t.Fatalf("failed to ParseFile %q: %v", fileName, err)
+		}
+		dir := filepath.Dir(fileName)
+		if _, ok := byDir[dir]; !ok {
+			byDir[dir] = nil
+		}
+		if f.Doc != nil {
+			byDir[dir] = append(byDir[dir], fileName)
+			txt := f.Doc.Text()
+			if strings.Contains(txt, "SPDX-License-Identifier") {
+				t.Errorf("the copyright header for %s became its package doc due to missing blank line", fileName)
+			}
+		}
+	}
+	for dir, ff := range byDir {
+		switch dir {
+		case "tstest/integration/vms":
+			// This package has a couple go:build ignore commands and this test doesn't
+			// handle parsing those. Just allowlist that package for now (2024-07-10).
+			continue
+		}
+		if len(ff) > 1 {
+			t.Logf("multiple files with package doc in %s: %q", dir, ff)
+		}
+		if len(ff) == 0 {
+			t.Errorf("no package doc in %s", dir)
+		}
+	}
+	t.Logf("parsed %d files", len(goFiles))
+}

posture/doc.go

@@ -0,0 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package posture contains functions to query the local system
+// state for managed posture checks.
+package posture

posture/hwaddr.go

@@ -0,0 +1,26 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package posture
+
+import (
+	"net/netip"
+	"slices"
+
+	"tailscale.com/net/netmon"
+)
+
+// GetHardwareAddrs returns the hardware addresses of all non-loopback
+// network interfaces.
+func GetHardwareAddrs() (hwaddrs []string, err error) {
+	err = netmon.ForeachInterface(func(i netmon.Interface, _ []netip.Prefix) {
+		if i.IsLoopback() {
+			return
+		}
+		if a := i.HardwareAddr.String(); a != "" {
+			hwaddrs = append(hwaddrs, a)
+		}
+	})
+	slices.Sort(hwaddrs)
+	return
+}