controlclient: add timing metrics for control requests

Updates #26869

.github/workflows/golangci-lint.yml

@@ -33,7 +33,7 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@2e788936b09dd82dc280e845628a40d2ba6b204c # v6.3.1
         with:
-          version: v1.60
+          version: v1.64
 
           # Show only new issues if it's a pull request.
           only-new-issues: true

Dockerfile

@@ -27,7 +27,7 @@
 #     $ docker exec tailscaled tailscale status
 
 
-FROM golang:1.23-alpine AS build-env
+FROM golang:1.24-alpine AS build-env
 
 WORKDIR /go/src/tailscale
 

appc/appconnector.go

@@ -289,9 +289,11 @@ func (e *AppConnector) updateDomains(domains []string) {
 				toRemove = append(toRemove, netip.PrefixFrom(a, a.BitLen()))
 			}
 		}
-		if err := e.routeAdvertiser.UnadvertiseRoute(toRemove...); err != nil {
-			e.logf("failed to unadvertise routes on domain removal: %v: %v: %v", slicesx.MapKeys(oldDomains), toRemove, err)
-		}
+		e.queue.Add(func() {
+			if err := e.routeAdvertiser.UnadvertiseRoute(toRemove...); err != nil {
+				e.logf("failed to unadvertise routes on domain removal: %v: %v: %v", slicesx.MapKeys(oldDomains), toRemove, err)
+			}
+		})
 	}
 
 	e.logf("handling domains: %v and wildcards: %v", slicesx.MapKeys(e.domains), e.wildcards)
@@ -310,11 +312,6 @@ func (e *AppConnector) updateRoutes(routes []netip.Prefix) {
 		return
 	}
 
-	if err := e.routeAdvertiser.AdvertiseRoute(routes...); err != nil {
-		e.logf("failed to advertise routes: %v: %v", routes, err)
-		return
-	}
-
 	var toRemove []netip.Prefix
 
 	// If we're storing routes and know e.controlRoutes is a good
@@ -338,9 +335,14 @@ nextRoute:
 		}
 	}
 
-	if err := e.routeAdvertiser.UnadvertiseRoute(toRemove...); err != nil {
-		e.logf("failed to unadvertise routes: %v: %v", toRemove, err)
-	}
+	e.queue.Add(func() {
+		if err := e.routeAdvertiser.AdvertiseRoute(routes...); err != nil {
+			e.logf("failed to advertise routes: %v: %v", routes, err)
+		}
+		if err := e.routeAdvertiser.UnadvertiseRoute(toRemove...); err != nil {
+			e.logf("failed to unadvertise routes: %v: %v", toRemove, err)
+		}
+	})
 
 	e.controlRoutes = routes
 	if err := e.storeRoutesLocked(); err != nil {

appc/appconnector_test.go

@@ -8,6 +8,7 @@ import (
 	"net/netip"
 	"reflect"
 	"slices"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -86,6 +87,7 @@ func TestUpdateRoutes(t *testing.T) {
 
 		routes := []netip.Prefix{netip.MustParsePrefix("192.0.2.0/24"), netip.MustParsePrefix("192.0.0.1/32")}
 		a.updateRoutes(routes)
+		a.Wait(ctx)
 
 		slices.SortFunc(rc.Routes(), prefixCompare)
 		rc.SetRoutes(slices.Compact(rc.Routes()))
@@ -105,6 +107,7 @@ func TestUpdateRoutes(t *testing.T) {
 }
 
 func TestUpdateRoutesUnadvertisesContainedRoutes(t *testing.T) {
+	ctx := context.Background()
 	for _, shouldStore := range []bool{false, true} {
 		rc := &appctest.RouteCollector{}
 		var a *AppConnector
@@ -117,6 +120,7 @@ func TestUpdateRoutesUnadvertisesContainedRoutes(t *testing.T) {
 		rc.SetRoutes([]netip.Prefix{netip.MustParsePrefix("192.0.2.1/32")})
 		routes := []netip.Prefix{netip.MustParsePrefix("192.0.2.0/24")}
 		a.updateRoutes(routes)
+		a.Wait(ctx)
 
 		if !slices.EqualFunc(routes, rc.Routes(), prefixEqual) {
 			t.Fatalf("got %v, want %v", rc.Routes(), routes)
@@ -636,3 +640,57 @@ func TestMetricBucketsAreSorted(t *testing.T) {
 		t.Errorf("metricStoreRoutesNBuckets must be in order")
 	}
 }
+
+// TestUpdateRoutesDeadlock is a regression test for a deadlock in
+// LocalBackend<->AppConnector interaction. When using real LocalBackend as the
+// routeAdvertiser, calls to Advertise/UnadvertiseRoutes can end up calling
+// back into AppConnector via authReconfig. If everything is called
+// synchronously, this results in a deadlock on AppConnector.mu.
+func TestUpdateRoutesDeadlock(t *testing.T) {
+	ctx := context.Background()
+	rc := &appctest.RouteCollector{}
+	a := NewAppConnector(t.Logf, rc, &RouteInfo{}, fakeStoreRoutes)
+
+	advertiseCalled := new(atomic.Bool)
+	unadvertiseCalled := new(atomic.Bool)
+	rc.AdvertiseCallback = func() {
+		// Call something that requires a.mu to be held.
+		a.DomainRoutes()
+		advertiseCalled.Store(true)
+	}
+	rc.UnadvertiseCallback = func() {
+		// Call something that requires a.mu to be held.
+		a.DomainRoutes()
+		unadvertiseCalled.Store(true)
+	}
+
+	a.updateDomains([]string{"example.com"})
+	a.Wait(ctx)
+
+	// Trigger rc.AdveriseRoute.
+	a.updateRoutes(
+		[]netip.Prefix{
+			netip.MustParsePrefix("127.0.0.1/32"),
+			netip.MustParsePrefix("127.0.0.2/32"),
+		},
+	)
+	a.Wait(ctx)
+	// Trigger rc.UnadveriseRoute.
+	a.updateRoutes(
+		[]netip.Prefix{
+			netip.MustParsePrefix("127.0.0.1/32"),
+		},
+	)
+	a.Wait(ctx)
+
+	if !advertiseCalled.Load() {
+		t.Error("AdvertiseRoute was not called")
+	}
+	if !unadvertiseCalled.Load() {
+		t.Error("UnadvertiseRoute was not called")
+	}
+
+	if want := []netip.Prefix{netip.MustParsePrefix("127.0.0.1/32")}; !slices.Equal(slices.Compact(rc.Routes()), want) {
+		t.Fatalf("got %v, want %v", rc.Routes(), want)
+	}
+}

appc/appctest/appctest.go

@@ -11,12 +11,22 @@ import (
 
 // RouteCollector is a test helper that collects the list of routes advertised
 type RouteCollector struct {
+	// AdvertiseCallback (optional) is called synchronously from
+	// AdvertiseRoute.
+	AdvertiseCallback func()
+	// UnadvertiseCallback (optional) is called synchronously from
+	// UnadvertiseRoute.
+	UnadvertiseCallback func()
+
 	routes        []netip.Prefix
 	removedRoutes []netip.Prefix
 }
 
 func (rc *RouteCollector) AdvertiseRoute(pfx ...netip.Prefix) error {
 	rc.routes = append(rc.routes, pfx...)
+	if rc.AdvertiseCallback != nil {
+		rc.AdvertiseCallback()
+	}
 	return nil
 }
 
@@ -30,6 +40,9 @@ func (rc *RouteCollector) UnadvertiseRoute(toRemove ...netip.Prefix) error {
 			rc.removedRoutes = append(rc.removedRoutes, r)
 		}
 	}
+	if rc.UnadvertiseCallback != nil {
+		rc.UnadvertiseCallback()
+	}
 	return nil
 }
 

client/systray/systray.go

@@ -72,6 +72,11 @@ type Menu struct {
 	curProfile  ipn.LoginProfile
 	allProfiles []ipn.LoginProfile
 
+	// readonly is whether the systray app is running in read-only mode.
+	// This is set if LocalAPI returns a permission error,
+	// typically because the user needs to run `tailscale set --operator=$USER`.
+	readonly bool
+
 	bgCtx    context.Context // ctx for background tasks not involving menu item clicks
 	bgCancel context.CancelFunc
 
@@ -153,6 +158,8 @@ func (menu *Menu) updateState() {
 	defer menu.mu.Unlock()
 	menu.init()
 
+	menu.readonly = false
+
 	var err error
 	menu.status, err = menu.lc.Status(menu.bgCtx)
 	if err != nil {
@@ -160,6 +167,9 @@ func (menu *Menu) updateState() {
 	}
 	menu.curProfile, menu.allProfiles, err = menu.lc.ProfileStatus(menu.bgCtx)
 	if err != nil {
+		if local.IsAccessDeniedError(err) {
+			menu.readonly = true
+		}
 		log.Print(err)
 	}
 }
@@ -182,6 +192,15 @@ func (menu *Menu) rebuild() {
 
 	systray.ResetMenu()
 
+	if menu.readonly {
+		const readonlyMsg = "No permission to manage Tailscale.\nSee tailscale.com/s/cli-operator"
+		m := systray.AddMenuItem(readonlyMsg, "")
+		onClick(ctx, m, func(_ context.Context) {
+			webbrowser.Open("https://tailscale.com/s/cli-operator")
+		})
+		systray.AddSeparator()
+	}
+
 	menu.connect = systray.AddMenuItem("Connect", "")
 	menu.disconnect = systray.AddMenuItem("Disconnect", "")
 	menu.disconnect.Hide()
@@ -222,28 +241,35 @@ func (menu *Menu) rebuild() {
 		setAppIcon(disconnected)
 	}
 
+	if menu.readonly {
+		menu.connect.Disable()
+		menu.disconnect.Disable()
+	}
+
 	account := "Account"
 	if pt := profileTitle(menu.curProfile); pt != "" {
 		account = pt
 	}
-	accounts := systray.AddMenuItem(account, "")
-	setRemoteIcon(accounts, menu.curProfile.UserProfile.ProfilePicURL)
-	time.Sleep(newMenuDelay)
-	for _, profile := range menu.allProfiles {
-		title := profileTitle(profile)
-		var item *systray.MenuItem
-		if profile.ID == menu.curProfile.ID {
-			item = accounts.AddSubMenuItemCheckbox(title, "", true)
-		} else {
-			item = accounts.AddSubMenuItem(title, "")
-		}
-		setRemoteIcon(item, profile.UserProfile.ProfilePicURL)
-		onClick(ctx, item, func(ctx context.Context) {
-			select {
-			case <-ctx.Done():
-			case menu.accountsCh <- profile.ID:
+	if !menu.readonly {
+		accounts := systray.AddMenuItem(account, "")
+		setRemoteIcon(accounts, menu.curProfile.UserProfile.ProfilePicURL)
+		time.Sleep(newMenuDelay)
+		for _, profile := range menu.allProfiles {
+			title := profileTitle(profile)
+			var item *systray.MenuItem
+			if profile.ID == menu.curProfile.ID {
+				item = accounts.AddSubMenuItemCheckbox(title, "", true)
+			} else {
+				item = accounts.AddSubMenuItem(title, "")
 			}
-		})
+			setRemoteIcon(item, profile.UserProfile.ProfilePicURL)
+			onClick(ctx, item, func(ctx context.Context) {
+				select {
+				case <-ctx.Done():
+				case menu.accountsCh <- profile.ID:
+				}
+			})
+		}
 	}
 
 	if menu.status != nil && menu.status.Self != nil && len(menu.status.Self.TailscaleIPs) > 0 {
@@ -255,7 +281,9 @@ func (menu *Menu) rebuild() {
 	}
 	systray.AddSeparator()
 
-	menu.rebuildExitNodeMenu(ctx)
+	if !menu.readonly {
+		menu.rebuildExitNodeMenu(ctx)
+	}
 
 	if menu.status != nil {
 		menu.more = systray.AddMenuItem("More settings", "")

client/tailscale/acl.go

@@ -12,6 +12,7 @@ import (
 	"fmt"
 	"net/http"
 	"net/netip"
+	"net/url"
 )
 
 // ACLRow defines a rule that grants access by a set of users or groups to a set
@@ -83,7 +84,7 @@ func (c *Client) ACL(ctx context.Context) (acl *ACL, err error) {
 		}
 	}()
 
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl", c.baseURL(), c.tailnet)
+	path := c.BuildTailnetURL("acl")
 	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
 	if err != nil {
 		return nil, err
@@ -97,7 +98,7 @@ func (c *Client) ACL(ctx context.Context) (acl *ACL, err error) {
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	// Otherwise, try to decode the response.
@@ -126,7 +127,7 @@ func (c *Client) ACLHuJSON(ctx context.Context) (acl *ACLHuJSON, err error) {
 		}
 	}()
 
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl?details=1", c.baseURL(), c.tailnet)
+	path := c.BuildTailnetURL("acl", url.Values{"details": {"1"}})
 	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
 	if err != nil {
 		return nil, err
@@ -138,7 +139,7 @@ func (c *Client) ACLHuJSON(ctx context.Context) (acl *ACLHuJSON, err error) {
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	data := struct {
@@ -146,7 +147,7 @@ func (c *Client) ACLHuJSON(ctx context.Context) (acl *ACLHuJSON, err error) {
 		Warnings []string `json:"warnings"`
 	}{}
 	if err := json.Unmarshal(b, &data); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("json.Unmarshal %q: %w", b, err)
 	}
 
 	acl = &ACLHuJSON{
@@ -184,7 +185,7 @@ func (e ACLTestError) Error() string {
 }
 
 func (c *Client) aclPOSTRequest(ctx context.Context, body []byte, avoidCollisions bool, etag, acceptHeader string) ([]byte, string, error) {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl", c.baseURL(), c.tailnet)
+	path := c.BuildTailnetURL("acl")
 	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(body))
 	if err != nil {
 		return nil, "", err
@@ -328,7 +329,7 @@ type ACLPreview struct {
 }
 
 func (c *Client) previewACLPostRequest(ctx context.Context, body []byte, previewType string, previewFor string) (res *ACLPreviewResponse, err error) {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl/preview", c.baseURL(), c.tailnet)
+	path := c.BuildTailnetURL("acl", "preview")
 	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(body))
 	if err != nil {
 		return nil, err
@@ -350,7 +351,7 @@ func (c *Client) previewACLPostRequest(ctx context.Context, body []byte, preview
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 	if err = json.Unmarshal(b, &res); err != nil {
 		return nil, err
@@ -488,7 +489,7 @@ func (c *Client) ValidateACLJSON(ctx context.Context, source, dest string) (test
 		return nil, err
 	}
 
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/acl/validate", c.baseURL(), c.tailnet)
+	path := c.BuildTailnetURL("acl", "validate")
 	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewBuffer(postData))
 	if err != nil {
 		return nil, err

client/tailscale/devices.go

@@ -131,7 +131,7 @@ func (c *Client) Devices(ctx context.Context, fields *DeviceFieldsOpts) (deviceL
 		}
 	}()
 
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/devices", c.baseURL(), c.tailnet)
+	path := c.BuildTailnetURL("devices")
 	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
 	if err != nil {
 		return nil, err
@@ -149,7 +149,7 @@ func (c *Client) Devices(ctx context.Context, fields *DeviceFieldsOpts) (deviceL
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	var devices GetDevicesResponse
@@ -188,7 +188,7 @@ func (c *Client) Device(ctx context.Context, deviceID string, fields *DeviceFiel
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	err = json.Unmarshal(b, &device)
@@ -221,7 +221,7 @@ func (c *Client) DeleteDevice(ctx context.Context, deviceID string) (err error)
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return handleErrorResponse(b, resp)
+		return HandleErrorResponse(b, resp)
 	}
 	return nil
 }
@@ -253,7 +253,7 @@ func (c *Client) SetAuthorized(ctx context.Context, deviceID string, authorized
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return handleErrorResponse(b, resp)
+		return HandleErrorResponse(b, resp)
 	}
 
 	return nil
@@ -281,7 +281,7 @@ func (c *Client) SetTags(ctx context.Context, deviceID string, tags []string) er
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return handleErrorResponse(b, resp)
+		return HandleErrorResponse(b, resp)
 	}
 
 	return nil

client/tailscale/dns.go

@@ -44,7 +44,7 @@ type DNSPreferences struct {
 }
 
 func (c *Client) dnsGETRequest(ctx context.Context, endpoint string) ([]byte, error) {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/dns/%s", c.baseURL(), c.tailnet, endpoint)
+	path := c.BuildTailnetURL("dns", endpoint)
 	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
 	if err != nil {
 		return nil, err
@@ -57,14 +57,14 @@ func (c *Client) dnsGETRequest(ctx context.Context, endpoint string) ([]byte, er
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	return b, nil
 }
 
 func (c *Client) dnsPOSTRequest(ctx context.Context, endpoint string, postData any) ([]byte, error) {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/dns/%s", c.baseURL(), c.tailnet, endpoint)
+	path := c.BuildTailnetURL("dns", endpoint)
 	data, err := json.Marshal(&postData)
 	if err != nil {
 		return nil, err
@@ -84,7 +84,7 @@ func (c *Client) dnsPOSTRequest(ctx context.Context, endpoint string, postData a
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	return b, nil

client/tailscale/keys.go

@@ -40,7 +40,7 @@ type KeyDeviceCreateCapabilities struct {
 
 // Keys returns the list of keys for the current user.
 func (c *Client) Keys(ctx context.Context) ([]string, error) {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/keys", c.baseURL(), c.tailnet)
+	path := c.BuildTailnetURL("keys")
 	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
 	if err != nil {
 		return nil, err
@@ -51,7 +51,7 @@ func (c *Client) Keys(ctx context.Context) ([]string, error) {
 		return nil, err
 	}
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	var keys struct {
@@ -99,7 +99,7 @@ func (c *Client) CreateKeyWithExpiry(ctx context.Context, caps KeyCapabilities,
 		return "", nil, err
 	}
 
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/keys", c.baseURL(), c.tailnet)
+	path := c.BuildTailnetURL("keys")
 	req, err := http.NewRequestWithContext(ctx, "POST", path, bytes.NewReader(bs))
 	if err != nil {
 		return "", nil, err
@@ -110,7 +110,7 @@ func (c *Client) CreateKeyWithExpiry(ctx context.Context, caps KeyCapabilities,
 		return "", nil, err
 	}
 	if resp.StatusCode != http.StatusOK {
-		return "", nil, handleErrorResponse(b, resp)
+		return "", nil, HandleErrorResponse(b, resp)
 	}
 
 	var key struct {
@@ -126,7 +126,7 @@ func (c *Client) CreateKeyWithExpiry(ctx context.Context, caps KeyCapabilities,
 // Key returns the metadata for the given key ID. Currently, capabilities are
 // only returned for auth keys, API keys only return general metadata.
 func (c *Client) Key(ctx context.Context, id string) (*Key, error) {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/keys/%s", c.baseURL(), c.tailnet, id)
+	path := c.BuildTailnetURL("keys", id)
 	req, err := http.NewRequestWithContext(ctx, "GET", path, nil)
 	if err != nil {
 		return nil, err
@@ -137,7 +137,7 @@ func (c *Client) Key(ctx context.Context, id string) (*Key, error) {
 		return nil, err
 	}
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	var key Key
@@ -149,7 +149,7 @@ func (c *Client) Key(ctx context.Context, id string) (*Key, error) {
 
 // DeleteKey deletes the key with the given ID.
 func (c *Client) DeleteKey(ctx context.Context, id string) error {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/keys/%s", c.baseURL(), c.tailnet, id)
+	path := c.BuildTailnetURL("keys", id)
 	req, err := http.NewRequestWithContext(ctx, "DELETE", path, nil)
 	if err != nil {
 		return err
@@ -160,7 +160,7 @@ func (c *Client) DeleteKey(ctx context.Context, id string) error {
 		return err
 	}
 	if resp.StatusCode != http.StatusOK {
-		return handleErrorResponse(b, resp)
+		return HandleErrorResponse(b, resp)
 	}
 	return nil
 }

client/tailscale/routes.go

@@ -44,7 +44,7 @@ func (c *Client) Routes(ctx context.Context, deviceID string) (routes *Routes, e
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	var sr Routes
@@ -84,7 +84,7 @@ func (c *Client) SetRoutes(ctx context.Context, deviceID string, subnets []netip
 	// If status code was not successful, return the error.
 	// TODO: Change the check for the StatusCode to include other 2XX success codes.
 	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
+		return nil, HandleErrorResponse(b, resp)
 	}
 
 	var srr *Routes

client/tailscale/tailnet.go

@@ -9,7 +9,6 @@ import (
 	"context"
 	"fmt"
 	"net/http"
-	"net/url"
 
 	"tailscale.com/util/httpm"
 )
@@ -22,7 +21,7 @@ func (c *Client) TailnetDeleteRequest(ctx context.Context, tailnetID string) (er
 		}
 	}()
 
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s", c.baseURL(), url.PathEscape(string(tailnetID)))
+	path := c.BuildTailnetURL("tailnet")
 	req, err := http.NewRequestWithContext(ctx, httpm.DELETE, path, nil)
 	if err != nil {
 		return err
@@ -35,7 +34,7 @@ func (c *Client) TailnetDeleteRequest(ctx context.Context, tailnetID string) (er
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		return handleErrorResponse(b, resp)
+		return HandleErrorResponse(b, resp)
 	}
 
 	return nil

client/tailscale/tailscale.go

@@ -17,6 +17,8 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
+	"path"
 )
 
 // I_Acknowledge_This_API_Is_Unstable must be set true to use this package
@@ -63,6 +65,46 @@ func (c *Client) httpClient() *http.Client {
 	return http.DefaultClient
 }
 
+// BuildURL builds a url to http(s)://<apiserver>/api/v2/<slash-separated-pathElements>
+// using the given pathElements. It url escapes each path element, so the
+// caller doesn't need to worry about that. The last item of pathElements can
+// be of type url.Values to add a query string to the URL.
+//
+// For example, BuildURL(devices, 5) with the default server URL would result in
+// https://api.tailscale.com/api/v2/devices/5.
+func (c *Client) BuildURL(pathElements ...any) string {
+	elem := make([]string, 1, len(pathElements)+1)
+	elem[0] = "/api/v2"
+	var query string
+	for i, pathElement := range pathElements {
+		if uv, ok := pathElement.(url.Values); ok && i == len(pathElements)-1 {
+			query = uv.Encode()
+		} else {
+			elem = append(elem, url.PathEscape(fmt.Sprint(pathElement)))
+		}
+	}
+	url := c.baseURL() + path.Join(elem...)
+	if query != "" {
+		url += "?" + query
+	}
+	return url
+}
+
+// BuildTailnetURL builds a url to http(s)://<apiserver>/api/v2/tailnet/<tailnet>/<slash-separated-pathElements>
+// using the given pathElements. It url escapes each path element, so the
+// caller doesn't need to worry about that. The last item of pathElements can
+// be of type url.Values to add a query string to the URL.
+//
+// For example, BuildTailnetURL(policy, validate) with the default server URL and a tailnet of "example.com"
+// would result in https://api.tailscale.com/api/v2/tailnet/example.com/policy/validate.
+func (c *Client) BuildTailnetURL(pathElements ...any) string {
+	allElements := make([]any, 2, len(pathElements)+2)
+	allElements[0] = "tailnet"
+	allElements[1] = c.tailnet
+	allElements = append(allElements, pathElements...)
+	return c.BuildURL(allElements...)
+}
+
 func (c *Client) baseURL() string {
 	if c.BaseURL != "" {
 		return c.BaseURL
@@ -150,12 +192,14 @@ func (e ErrResponse) Error() string {
 	return fmt.Sprintf("Status: %d, Message: %q", e.Status, e.Message)
 }
 
-// handleErrorResponse decodes the error message from the server and returns
+// HandleErrorResponse decodes the error message from the server and returns
 // an ErrResponse from it.
-func handleErrorResponse(b []byte, resp *http.Response) error {
+//
+// Deprecated: use tailscale.com/client/tailscale/v2 instead.
+func HandleErrorResponse(b []byte, resp *http.Response) error {
 	var errResp ErrResponse
 	if err := json.Unmarshal(b, &errResp); err != nil {
-		return err
+		return fmt.Errorf("json.Unmarshal %q: %w", b, err)
 	}
 	errResp.Status = resp.StatusCode
 	return errResp

client/tailscale/tailscale_test.go

@@ -0,0 +1,86 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package tailscale
+
+import (
+	"net/url"
+	"testing"
+)
+
+func TestClientBuildURL(t *testing.T) {
+	c := Client{BaseURL: "http://127.0.0.1:1234"}
+	for _, tt := range []struct {
+		desc     string
+		elements []any
+		want     string
+	}{
+		{
+			desc:     "single-element",
+			elements: []any{"devices"},
+			want:     "http://127.0.0.1:1234/api/v2/devices",
+		},
+		{
+			desc:     "multiple-elements",
+			elements: []any{"tailnet", "example.com"},
+			want:     "http://127.0.0.1:1234/api/v2/tailnet/example.com",
+		},
+		{
+			desc:     "escape-element",
+			elements: []any{"tailnet", "example dot com?foo=bar"},
+			want:     `http://127.0.0.1:1234/api/v2/tailnet/example%20dot%20com%3Ffoo=bar`,
+		},
+		{
+			desc:     "url.Values",
+			elements: []any{"tailnet", "example.com", "acl", url.Values{"details": {"1"}}},
+			want:     `http://127.0.0.1:1234/api/v2/tailnet/example.com/acl?details=1`,
+		},
+	} {
+		t.Run(tt.desc, func(t *testing.T) {
+			got := c.BuildURL(tt.elements...)
+			if got != tt.want {
+				t.Errorf("got %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestClientBuildTailnetURL(t *testing.T) {
+	c := Client{
+		BaseURL: "http://127.0.0.1:1234",
+		tailnet: "example.com",
+	}
+	for _, tt := range []struct {
+		desc     string
+		elements []any
+		want     string
+	}{
+		{
+			desc:     "single-element",
+			elements: []any{"devices"},
+			want:     "http://127.0.0.1:1234/api/v2/tailnet/example.com/devices",
+		},
+		{
+			desc:     "multiple-elements",
+			elements: []any{"devices", 123},
+			want:     "http://127.0.0.1:1234/api/v2/tailnet/example.com/devices/123",
+		},
+		{
+			desc:     "escape-element",
+			elements: []any{"foo bar?baz=qux"},
+			want:     `http://127.0.0.1:1234/api/v2/tailnet/example.com/foo%20bar%3Fbaz=qux`,
+		},
+		{
+			desc:     "url.Values",
+			elements: []any{"acl", url.Values{"details": {"1"}}},
+			want:     `http://127.0.0.1:1234/api/v2/tailnet/example.com/acl?details=1`,
+		},
+	} {
+		t.Run(tt.desc, func(t *testing.T) {
+			got := c.BuildTailnetURL(tt.elements...)
+			if got != tt.want {
+				t.Errorf("got %q, want %q", got, tt.want)
+			}
+		})
+	}
+}

client/web/web.go

@@ -203,35 +203,9 @@ func NewServer(opts ServerOpts) (s *Server, err error) {
 	}
 	s.assetsHandler, s.assetsCleanup = assetsHandler(s.devMode)
 
-	var metric string // clientmetric to report on startup
-
-	// Create handler for "/api" requests with CSRF protection.
-	// We don't require secure cookies, since the web client is regularly used
-	// on network appliances that are served on local non-https URLs.
-	// The client is secured by limiting the interface it listens on,
-	// or by authenticating requests before they reach the web client.
-	csrfProtect := csrf.Protect(s.csrfKey(), csrf.Secure(false))
-
-	// signal to the CSRF middleware that the request is being served over
-	// plaintext HTTP to skip TLS-only header checks.
-	withSetPlaintext := func(h http.Handler) http.Handler {
-		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			r = csrf.PlaintextHTTPRequest(r)
-			h.ServeHTTP(w, r)
-		})
-	}
-
-	switch s.mode {
-	case LoginServerMode:
-		s.apiHandler = csrfProtect(withSetPlaintext(http.HandlerFunc(s.serveLoginAPI)))
-		metric = "web_login_client_initialization"
-	case ReadOnlyServerMode:
-		s.apiHandler = csrfProtect(withSetPlaintext(http.HandlerFunc(s.serveLoginAPI)))
-		metric = "web_readonly_client_initialization"
-	case ManageServerMode:
-		s.apiHandler = csrfProtect(withSetPlaintext(http.HandlerFunc(s.serveAPI)))
-		metric = "web_client_initialization"
-	}
+	var metric string
+	s.apiHandler, metric = s.modeAPIHandler(s.mode)
+	s.apiHandler = s.withCSRF(s.apiHandler)
 
 	// Don't block startup on reporting metric.
 	// Report in separate go routine with 5 second timeout.
@@ -244,6 +218,39 @@ func NewServer(opts ServerOpts) (s *Server, err error) {
 	return s, nil
 }
 
+func (s *Server) withCSRF(h http.Handler) http.Handler {
+	csrfProtect := csrf.Protect(s.csrfKey(), csrf.Secure(false))
+
+	// ref https://github.com/tailscale/tailscale/pull/14822
+	// signal to the CSRF middleware that the request is being served over
+	// plaintext HTTP to skip TLS-only header checks.
+	withSetPlaintext := func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			r = csrf.PlaintextHTTPRequest(r)
+			h.ServeHTTP(w, r)
+		})
+	}
+
+	// NB: the order of the withSetPlaintext and csrfProtect calls is important
+	// to ensure that we signal to the CSRF middleware that the request is being
+	// served over plaintext HTTP and not over TLS as it presumes by default.
+	return withSetPlaintext(csrfProtect(h))
+}
+
+func (s *Server) modeAPIHandler(mode ServerMode) (http.Handler, string) {
+	switch mode {
+	case LoginServerMode:
+		return http.HandlerFunc(s.serveLoginAPI), "web_login_client_initialization"
+	case ReadOnlyServerMode:
+		return http.HandlerFunc(s.serveLoginAPI), "web_readonly_client_initialization"
+	case ManageServerMode:
+		return http.HandlerFunc(s.serveAPI), "web_client_initialization"
+	default: // invalid mode
+		log.Fatalf("invalid mode: %v", mode)
+	}
+	return nil, ""
+}
+
 func (s *Server) Shutdown() {
 	s.logf("web.Server: shutting down")
 	if s.assetsCleanup != nil {

client/web/web_test.go

@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/http/cookiejar"
 	"net/http/httptest"
 	"net/netip"
 	"net/url"
@@ -20,6 +21,7 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/gorilla/csrf"
 	"tailscale.com/client/local"
 	"tailscale.com/client/tailscale/apitype"
 	"tailscale.com/ipn"
@@ -1477,3 +1479,83 @@ func mockWaitAuthURL(_ context.Context, id string, src tailcfg.NodeID) (*tailcfg
 		return nil, errors.New("unknown id")
 	}
 }
+
+func TestCSRFProtect(t *testing.T) {
+	s := &Server{}
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("GET /test/csrf-token", func(w http.ResponseWriter, r *http.Request) {
+		token := csrf.Token(r)
+		_, err := io.WriteString(w, token)
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+	mux.HandleFunc("POST /test/csrf-protected", func(w http.ResponseWriter, r *http.Request) {
+		_, err := io.WriteString(w, "ok")
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+	h := s.withCSRF(mux)
+	ser := httptest.NewServer(h)
+	defer ser.Close()
+
+	jar, err := cookiejar.New(nil)
+	if err != nil {
+		t.Fatalf("unable to construct cookie jar: %v", err)
+	}
+
+	client := ser.Client()
+	client.Jar = jar
+
+	// make GET request to populate cookie jar
+	resp, err := client.Get(ser.URL + "/test/csrf-token")
+	if err != nil {
+		t.Fatalf("unable to make request: %v", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("unexpected status: %v", resp.Status)
+	}
+	tokenBytes, err := io.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatalf("unable to read body: %v", err)
+	}
+
+	csrfToken := strings.TrimSpace(string(tokenBytes))
+	if csrfToken == "" {
+		t.Fatal("empty csrf token")
+	}
+
+	// make a POST request without the CSRF header; ensure it fails
+	resp, err = client.Post(ser.URL+"/test/csrf-protected", "text/plain", nil)
+	if err != nil {
+		t.Fatalf("unable to make request: %v", err)
+	}
+	if resp.StatusCode != http.StatusForbidden {
+		t.Fatalf("unexpected status: %v", resp.Status)
+	}
+
+	// make a POST request with the CSRF header; ensure it succeeds
+	req, err := http.NewRequest("POST", ser.URL+"/test/csrf-protected", nil)
+	if err != nil {
+		t.Fatalf("error building request: %v", err)
+	}
+	req.Header.Set("X-CSRF-Token", csrfToken)
+	resp, err = client.Do(req)
+	if err != nil {
+		t.Fatalf("unable to make request: %v", err)
+	}
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("unexpected status: %v", resp.Status)
+	}
+	defer resp.Body.Close()
+	out, err := io.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatalf("unable to read body: %v", err)
+	}
+	if string(out) != "ok" {
+		t.Fatalf("unexpected body: %q", out)
+	}
+}

cmd/containerboot/serve.go

@@ -35,6 +35,8 @@ func watchServeConfigChanges(ctx context.Context, path string, cdChanged <-chan
 	var tickChan <-chan time.Time
 	var eventChan <-chan fsnotify.Event
 	if w, err := fsnotify.NewWatcher(); err != nil {
+		// Creating a new fsnotify watcher would fail for example if inotify was not able to create a new file descriptor.
+		// See https://github.com/tailscale/tailscale/issues/15081
 		log.Printf("serve proxy: failed to create fsnotify watcher, timer-only mode: %v", err)
 		ticker := time.NewTicker(5 * time.Second)
 		defer ticker.Stop()

cmd/containerboot/tailscaled.go

@@ -173,11 +173,14 @@ func tailscaleSet(ctx context.Context, cfg *settings) error {
 func watchTailscaledConfigChanges(ctx context.Context, path string, lc *local.Client, errCh chan<- error) {
 	var (
 		tickChan          <-chan time.Time
+		eventChan         <-chan fsnotify.Event
+		errChan           <-chan error
 		tailscaledCfgDir  = filepath.Dir(path)
 		prevTailscaledCfg []byte
 	)
-	w, err := fsnotify.NewWatcher()
-	if err != nil {
+	if w, err := fsnotify.NewWatcher(); err != nil {
+		// Creating a new fsnotify watcher would fail for example if inotify was not able to create a new file descriptor.
+		// See https://github.com/tailscale/tailscale/issues/15081
 		log.Printf("tailscaled config watch: failed to create fsnotify watcher, timer-only mode: %v", err)
 		ticker := time.NewTicker(5 * time.Second)
 		defer ticker.Stop()
@@ -188,6 +191,8 @@ func watchTailscaledConfigChanges(ctx context.Context, path string, lc *local.Cl
 			errCh <- fmt.Errorf("failed to add fsnotify watch: %w", err)
 			return
 		}
+		eventChan = w.Events
+		errChan = w.Errors
 	}
 	b, err := os.ReadFile(path)
 	if err != nil {
@@ -205,11 +210,11 @@ func watchTailscaledConfigChanges(ctx context.Context, path string, lc *local.Cl
 		select {
 		case <-ctx.Done():
 			return
-		case err := <-w.Errors:
+		case err := <-errChan:
 			errCh <- fmt.Errorf("watcher error: %w", err)
 			return
 		case <-tickChan:
-		case event := <-w.Events:
+		case event := <-eventChan:
 			if event.Name != toWatch {
 				continue
 			}

cmd/derper/depaware.txt

@@ -191,13 +191,11 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         golang.org/x/crypto/cryptobyte                               from crypto/ecdsa+
         golang.org/x/crypto/cryptobyte/asn1                          from crypto/ecdsa+
         golang.org/x/crypto/curve25519                               from golang.org/x/crypto/nacl/box+
-        golang.org/x/crypto/hkdf                                     from crypto/tls+
         golang.org/x/crypto/internal/alias                           from golang.org/x/crypto/chacha20+
         golang.org/x/crypto/internal/poly1305                        from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
-        golang.org/x/crypto/sha3                                     from crypto/internal/mlkem768+
    W    golang.org/x/exp/constraints                                 from tailscale.com/util/winutil
         golang.org/x/exp/maps                                        from tailscale.com/util/syspolicy/setting+
    L    golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
@@ -230,7 +228,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         container/list                                               from crypto/tls+
         context                                                      from crypto/tls+
         crypto                                                       from crypto/ecdh+
-        crypto/aes                                                   from crypto/ecdsa+
+        crypto/aes                                                   from crypto/internal/hpke+
         crypto/cipher                                                from crypto/aes+
         crypto/des                                                   from crypto/tls+
         crypto/dsa                                                   from crypto/x509
@@ -239,31 +237,58 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         crypto/ed25519                                               from crypto/tls+
         crypto/elliptic                                              from crypto/ecdsa+
         crypto/hmac                                                  from crypto/tls+
-        crypto/internal/alias                                        from crypto/aes+
-        crypto/internal/bigmod                                       from crypto/ecdsa+
         crypto/internal/boring                                       from crypto/aes+
         crypto/internal/boring/bbig                                  from crypto/ecdsa+
         crypto/internal/boring/sig                                   from crypto/internal/boring
-        crypto/internal/edwards25519                                 from crypto/ed25519
-        crypto/internal/edwards25519/field                           from crypto/ecdh+
+        crypto/internal/entropy                                      from crypto/internal/fips140/drbg
+        crypto/internal/fips140                                      from crypto/internal/fips140/aes+
+        crypto/internal/fips140/aes                                  from crypto/aes+
+        crypto/internal/fips140/aes/gcm                              from crypto/cipher+
+        crypto/internal/fips140/alias                                from crypto/cipher+
+        crypto/internal/fips140/bigmod                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/check                                from crypto/internal/fips140/aes+
+        crypto/internal/fips140/drbg                                 from crypto/internal/fips140/aes/gcm+
+        crypto/internal/fips140/ecdh                                 from crypto/ecdh
+        crypto/internal/fips140/ecdsa                                from crypto/ecdsa
+        crypto/internal/fips140/ed25519                              from crypto/ed25519
+        crypto/internal/fips140/edwards25519                         from crypto/internal/fips140/ed25519
+        crypto/internal/fips140/edwards25519/field                   from crypto/ecdh+
+        crypto/internal/fips140/hkdf                                 from crypto/internal/fips140/tls13+
+        crypto/internal/fips140/hmac                                 from crypto/hmac+
+        crypto/internal/fips140/mlkem                                from crypto/tls
+        crypto/internal/fips140/nistec                               from crypto/elliptic+
+        crypto/internal/fips140/nistec/fiat                          from crypto/internal/fips140/nistec
+        crypto/internal/fips140/rsa                                  from crypto/rsa
+        crypto/internal/fips140/sha256                               from crypto/internal/fips140/check+
+        crypto/internal/fips140/sha3                                 from crypto/internal/fips140/hmac+
+        crypto/internal/fips140/sha512                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/subtle                               from crypto/internal/fips140/aes+
+        crypto/internal/fips140/tls12                                from crypto/tls
+        crypto/internal/fips140/tls13                                from crypto/tls
+        crypto/internal/fips140deps/byteorder                        from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/cpu                              from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/godebug                          from crypto/internal/fips140+
+        crypto/internal/fips140hash                                  from crypto/ecdsa+
+        crypto/internal/fips140only                                  from crypto/cipher+
         crypto/internal/hpke                                         from crypto/tls
-        crypto/internal/mlkem768                                     from crypto/tls
-        crypto/internal/nistec                                       from crypto/ecdh+
-        crypto/internal/nistec/fiat                                  from crypto/internal/nistec
+        crypto/internal/impl                                         from crypto/internal/fips140/aes+
         crypto/internal/randutil                                     from crypto/dsa+
+        crypto/internal/sysrand                                      from crypto/internal/entropy+
         crypto/md5                                                   from crypto/tls+
         crypto/rand                                                  from crypto/ed25519+
         crypto/rc4                                                   from crypto/tls
         crypto/rsa                                                   from crypto/tls+
         crypto/sha1                                                  from crypto/tls+
         crypto/sha256                                                from crypto/tls+
+        crypto/sha3                                                  from crypto/internal/fips140hash
         crypto/sha512                                                from crypto/ecdsa+
-        crypto/subtle                                                from crypto/aes+
+        crypto/subtle                                                from crypto/cipher+
         crypto/tls                                                   from golang.org/x/crypto/acme+
+        crypto/tls/internal/fips140tls                               from crypto/tls
         crypto/x509                                                  from crypto/tls+
    D    crypto/x509/internal/macos                                   from crypto/x509
         crypto/x509/pkix                                             from crypto/x509+
-        embed                                                        from crypto/internal/nistec+
+        embed                                                        from google.golang.org/protobuf/internal/editiondefaults+
         encoding                                                     from encoding/json+
         encoding/asn1                                                from crypto/x509+
         encoding/base32                                              from github.com/fxamacker/cbor/v2+
@@ -284,23 +309,22 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         html                                                         from net/http/pprof+
         html/template                                                from tailscale.com/cmd/derper
         internal/abi                                                 from crypto/x509/internal/macos+
-        internal/asan                                                from syscall
+        internal/asan                                                from syscall+
         internal/bisect                                              from internal/godebug
         internal/bytealg                                             from bytes+
-        internal/byteorder                                           from crypto/aes+
+        internal/byteorder                                           from crypto/cipher+
         internal/chacha8rand                                         from math/rand/v2+
-        internal/concurrent                                          from unique
         internal/coverage/rtcov                                      from runtime
-        internal/cpu                                                 from crypto/aes+
+        internal/cpu                                                 from crypto/internal/fips140deps/cpu+
         internal/filepathlite                                        from os+
         internal/fmtsort                                             from fmt+
-        internal/goarch                                              from crypto/aes+
+        internal/goarch                                              from crypto/internal/fips140deps/cpu+
         internal/godebug                                             from crypto/tls+
         internal/godebugs                                            from internal/godebug+
-        internal/goexperiment                                        from runtime
+        internal/goexperiment                                        from runtime+
         internal/goos                                                from crypto/x509+
         internal/itoa                                                from internal/poll+
-        internal/msan                                                from syscall
+        internal/msan                                                from syscall+
         internal/nettrace                                            from net+
         internal/oserror                                             from io/fs+
         internal/poll                                                from net+
@@ -310,17 +334,20 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         internal/reflectlite                                         from context+
         internal/runtime/atomic                                      from internal/runtime/exithook+
         internal/runtime/exithook                                    from runtime
+        internal/runtime/maps                                        from reflect+
+        internal/runtime/math                                        from internal/runtime/maps+
+        internal/runtime/sys                                         from crypto/subtle+
    L    internal/runtime/syscall                                     from runtime+
         internal/singleflight                                        from net
         internal/stringslite                                         from embed+
+        internal/sync                                                from sync+
         internal/syscall/execenv                                     from os+
-  LD    internal/syscall/unix                                        from crypto/rand+
-   W    internal/syscall/windows                                     from crypto/rand+
+  LD    internal/syscall/unix                                        from crypto/internal/sysrand+
+   W    internal/syscall/windows                                     from crypto/internal/sysrand+
    W    internal/syscall/windows/registry                            from mime+
    W    internal/syscall/windows/sysdll                              from internal/syscall/windows+
         internal/testlog                                             from os
         internal/unsafeheader                                        from internal/reflectlite+
-        internal/weak                                                from unique
         io                                                           from bufio+
         io/fs                                                        from crypto/x509+
    L    io/ioutil                                                    from github.com/mitchellh/go-ps+
@@ -332,7 +359,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+
         math/rand                                                    from github.com/mdlayher/netlink+
-        math/rand/v2                                                 from internal/concurrent+
+        math/rand/v2                                                 from crypto/ecdsa+
         mime                                                         from github.com/prometheus/common/expfmt+
         mime/multipart                                               from net/http
         mime/quotedprintable                                         from mime/multipart
@@ -345,7 +372,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         net/netip                                                    from go4.org/netipx+
         net/textproto                                                from golang.org/x/net/http/httpguts+
         net/url                                                      from crypto/x509+
-        os                                                           from crypto/rand+
+        os                                                           from crypto/internal/sysrand+
         os/exec                                                      from github.com/coreos/go-iptables/iptables+
         os/signal                                                    from tailscale.com/cmd/derper
    W    os/user                                                      from tailscale.com/util/winutil+
@@ -354,10 +381,8 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         reflect                                                      from crypto/x509+
         regexp                                                       from github.com/coreos/go-iptables/iptables+
         regexp/syntax                                                from regexp
-        runtime                                                      from crypto/internal/nistec+
+        runtime                                                      from crypto/internal/fips140+
         runtime/debug                                                from github.com/prometheus/client_golang/prometheus+
-        runtime/internal/math                                        from runtime
-        runtime/internal/sys                                         from runtime
         runtime/metrics                                              from github.com/prometheus/client_golang/prometheus+
         runtime/pprof                                                from net/http/pprof
         runtime/trace                                                from net/http/pprof
@@ -367,7 +392,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         strings                                                      from bufio+
         sync                                                         from compress/flate+
         sync/atomic                                                  from context+
-        syscall                                                      from crypto/rand+
+        syscall                                                      from crypto/internal/sysrand+
         text/tabwriter                                               from runtime/pprof
         text/template                                                from html/template
         text/template/parse                                          from html/template+
@@ -377,3 +402,4 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         unicode/utf8                                                 from bufio+
         unique                                                       from net/netip
         unsafe                                                       from bytes+
+        weak                                                         from unique

cmd/derper/derper.go

@@ -71,10 +71,13 @@ var (
 	secretsCacheDir = flag.String("secrets-cache-dir", defaultSetecCacheDir(), "directory to cache setec secrets in (required if --secrets-url is set)")
 	bootstrapDNS    = flag.String("bootstrap-dns-names", "", "optional comma-separated list of hostnames to make available at /bootstrap-dns")
 	unpublishedDNS  = flag.String("unpublished-bootstrap-dns-names", "", "optional comma-separated list of hostnames to make available at /bootstrap-dns and not publish in the list. If an entry contains a slash, the second part names a DNS record to poll for its TXT record with a `0` to `100` value for rollout percentage.")
+
 	verifyClients   = flag.Bool("verify-clients", false, "verify clients to this DERP server through a local tailscaled instance.")
 	verifyClientURL = flag.String("verify-client-url", "", "if non-empty, an admission controller URL for permitting client connections; see tailcfg.DERPAdmitClientRequest")
 	verifyFailOpen  = flag.Bool("verify-client-url-fail-open", true, "whether we fail open if --verify-client-url is unreachable")
 
+	socket = flag.String("socket", "", "optional alternate path to tailscaled socket (only relevant when using --verify-clients)")
+
 	acceptConnLimit = flag.Float64("accept-connection-limit", math.Inf(+1), "rate limit for accepting new connection")
 	acceptConnBurst = flag.Int("accept-connection-burst", math.MaxInt, "burst limit for accepting new connection")
 
@@ -192,6 +195,7 @@ func main() {
 
 	s := derp.NewServer(cfg.PrivateKey, log.Printf)
 	s.SetVerifyClient(*verifyClients)
+	s.SetTailscaledSocketPath(*socket)
 	s.SetVerifyClientURL(*verifyClientURL)
 	s.SetVerifyClientURLFailOpen(*verifyFailOpen)
 	s.SetTCPWriteTimeout(*tcpWriteTimeout)
@@ -324,6 +328,9 @@ func main() {
 		Control:   ktimeout.UserTimeout(*tcpUserTimeout),
 		KeepAlive: *tcpKeepAlive,
 	}
+	// As of 2025-02-19, MPTCP does not support TCP_USER_TIMEOUT socket option
+	// set in ktimeout.UserTimeout above.
+	lc.SetMultipathTCP(false)
 
 	quietLogger := log.New(logger.HTTPServerLogFilter{Inner: log.Printf}, "", 0)
 	httpsrv := &http.Server{

cmd/gitops-pusher/gitops-pusher.go

@@ -13,6 +13,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
+	"io"
 	"log"
 	"net/http"
 	"os"
@@ -405,7 +406,8 @@ func getACLETag(ctx context.Context, client *http.Client, tailnet, apiKey string
 	got := resp.StatusCode
 	want := http.StatusOK
 	if got != want {
-		return "", fmt.Errorf("wanted HTTP status code %d but got %d", want, got)
+		errorDetails, _ := io.ReadAll(resp.Body)
+		return "", fmt.Errorf("wanted HTTP status code %d but got %d: %#q", want, got, string(errorDetails))
 	}
 
 	return Shuck(resp.Header.Get("ETag")), nil

cmd/k8s-operator/depaware.txt

@@ -997,14 +997,13 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         golang.org/x/crypto/cryptobyte                               from crypto/ecdsa+
         golang.org/x/crypto/cryptobyte/asn1                          from crypto/ecdsa+
         golang.org/x/crypto/curve25519                               from golang.org/x/crypto/ssh+
-        golang.org/x/crypto/hkdf                                     from crypto/tls+
+        golang.org/x/crypto/hkdf                                     from tailscale.com/control/controlbase
         golang.org/x/crypto/internal/alias                           from golang.org/x/crypto/chacha20+
         golang.org/x/crypto/internal/poly1305                        from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/poly1305                                 from github.com/tailscale/wireguard-go/device
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
-        golang.org/x/crypto/sha3                                     from crypto/internal/mlkem768+
   LD    golang.org/x/crypto/ssh                                      from tailscale.com/ipn/ipnlocal
   LD    golang.org/x/crypto/ssh/internal/bcrypt_pbkdf                from golang.org/x/crypto/ssh
         golang.org/x/exp/constraints                                 from github.com/dblohm7/wingoes/pe+
@@ -1055,7 +1054,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         container/list                                               from crypto/tls+
         context                                                      from crypto/tls+
         crypto                                                       from crypto/ecdh+
-        crypto/aes                                                   from crypto/ecdsa+
+        crypto/aes                                                   from crypto/internal/hpke+
         crypto/cipher                                                from crypto/aes+
         crypto/des                                                   from crypto/tls+
         crypto/dsa                                                   from crypto/x509+
@@ -1064,27 +1063,54 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         crypto/ed25519                                               from crypto/tls+
         crypto/elliptic                                              from crypto/ecdsa+
         crypto/hmac                                                  from crypto/tls+
-        crypto/internal/alias                                        from crypto/aes+
-        crypto/internal/bigmod                                       from crypto/ecdsa+
         crypto/internal/boring                                       from crypto/aes+
         crypto/internal/boring/bbig                                  from crypto/ecdsa+
         crypto/internal/boring/sig                                   from crypto/internal/boring
-        crypto/internal/edwards25519                                 from crypto/ed25519
-        crypto/internal/edwards25519/field                           from crypto/ecdh+
+        crypto/internal/entropy                                      from crypto/internal/fips140/drbg
+        crypto/internal/fips140                                      from crypto/internal/fips140/aes+
+        crypto/internal/fips140/aes                                  from crypto/aes+
+        crypto/internal/fips140/aes/gcm                              from crypto/cipher+
+        crypto/internal/fips140/alias                                from crypto/cipher+
+        crypto/internal/fips140/bigmod                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/check                                from crypto/internal/fips140/aes+
+        crypto/internal/fips140/drbg                                 from crypto/internal/fips140/aes/gcm+
+        crypto/internal/fips140/ecdh                                 from crypto/ecdh
+        crypto/internal/fips140/ecdsa                                from crypto/ecdsa
+        crypto/internal/fips140/ed25519                              from crypto/ed25519
+        crypto/internal/fips140/edwards25519                         from crypto/internal/fips140/ed25519
+        crypto/internal/fips140/edwards25519/field                   from crypto/ecdh+
+        crypto/internal/fips140/hkdf                                 from crypto/internal/fips140/tls13+
+        crypto/internal/fips140/hmac                                 from crypto/hmac+
+        crypto/internal/fips140/mlkem                                from crypto/tls
+        crypto/internal/fips140/nistec                               from crypto/elliptic+
+        crypto/internal/fips140/nistec/fiat                          from crypto/internal/fips140/nistec
+        crypto/internal/fips140/rsa                                  from crypto/rsa
+        crypto/internal/fips140/sha256                               from crypto/internal/fips140/check+
+        crypto/internal/fips140/sha3                                 from crypto/internal/fips140/hmac+
+        crypto/internal/fips140/sha512                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/subtle                               from crypto/internal/fips140/aes+
+        crypto/internal/fips140/tls12                                from crypto/tls
+        crypto/internal/fips140/tls13                                from crypto/tls
+        crypto/internal/fips140deps/byteorder                        from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/cpu                              from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/godebug                          from crypto/internal/fips140+
+        crypto/internal/fips140hash                                  from crypto/ecdsa+
+        crypto/internal/fips140only                                  from crypto/cipher+
         crypto/internal/hpke                                         from crypto/tls
-        crypto/internal/mlkem768                                     from crypto/tls
-        crypto/internal/nistec                                       from crypto/ecdh+
-        crypto/internal/nistec/fiat                                  from crypto/internal/nistec
+        crypto/internal/impl                                         from crypto/internal/fips140/aes+
         crypto/internal/randutil                                     from crypto/dsa+
+        crypto/internal/sysrand                                      from crypto/internal/entropy+
         crypto/md5                                                   from crypto/tls+
         crypto/rand                                                  from crypto/ed25519+
         crypto/rc4                                                   from crypto/tls+
         crypto/rsa                                                   from crypto/tls+
         crypto/sha1                                                  from crypto/tls+
         crypto/sha256                                                from crypto/tls+
+        crypto/sha3                                                  from crypto/internal/fips140hash
         crypto/sha512                                                from crypto/ecdsa+
-        crypto/subtle                                                from crypto/aes+
+        crypto/subtle                                                from crypto/cipher+
         crypto/tls                                                   from github.com/aws/aws-sdk-go-v2/aws/transport/http+
+        crypto/tls/internal/fips140tls                               from crypto/tls
         crypto/x509                                                  from crypto/tls+
    D    crypto/x509/internal/macos                                   from crypto/x509
         crypto/x509/pkix                                             from crypto/x509+
@@ -1092,7 +1118,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         database/sql/driver                                          from database/sql+
    W    debug/dwarf                                                  from debug/pe
    W    debug/pe                                                     from github.com/dblohm7/wingoes/pe
-        embed                                                        from crypto/internal/nistec+
+        embed                                                        from github.com/tailscale/web-client-prebuilt+
         encoding                                                     from encoding/gob+
         encoding/asn1                                                from crypto/x509+
         encoding/base32                                              from github.com/fxamacker/cbor/v2+
@@ -1112,7 +1138,6 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         go/build/constraint                                          from go/parser
         go/doc                                                       from k8s.io/apimachinery/pkg/runtime
         go/doc/comment                                               from go/doc
-        go/internal/typeparams                                       from go/parser
         go/parser                                                    from k8s.io/apimachinery/pkg/runtime
         go/scanner                                                   from go/ast+
         go/token                                                     from go/ast+
@@ -1124,24 +1149,23 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         html                                                         from html/template+
         html/template                                                from github.com/gorilla/csrf
         internal/abi                                                 from crypto/x509/internal/macos+
-        internal/asan                                                from syscall
+        internal/asan                                                from syscall+
         internal/bisect                                              from internal/godebug
         internal/bytealg                                             from bytes+
-        internal/byteorder                                           from crypto/aes+
+        internal/byteorder                                           from crypto/cipher+
         internal/chacha8rand                                         from math/rand/v2+
-        internal/concurrent                                          from unique
         internal/coverage/rtcov                                      from runtime
-        internal/cpu                                                 from crypto/aes+
+        internal/cpu                                                 from crypto/internal/fips140deps/cpu+
         internal/filepathlite                                        from os+
         internal/fmtsort                                             from fmt+
-        internal/goarch                                              from crypto/aes+
+        internal/goarch                                              from crypto/internal/fips140deps/cpu+
         internal/godebug                                             from archive/tar+
         internal/godebugs                                            from internal/godebug+
-        internal/goexperiment                                        from runtime
+        internal/goexperiment                                        from runtime+
         internal/goos                                                from crypto/x509+
         internal/itoa                                                from internal/poll+
         internal/lazyregexp                                          from go/doc
-        internal/msan                                                from syscall
+        internal/msan                                                from syscall+
         internal/nettrace                                            from net+
         internal/oserror                                             from io/fs+
         internal/poll                                                from net+
@@ -1151,18 +1175,21 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         internal/reflectlite                                         from context+
         internal/runtime/atomic                                      from internal/runtime/exithook+
         internal/runtime/exithook                                    from runtime
+        internal/runtime/maps                                        from reflect+
+        internal/runtime/math                                        from internal/runtime/maps+
+        internal/runtime/sys                                         from crypto/subtle+
    L    internal/runtime/syscall                                     from runtime+
         internal/saferio                                             from debug/pe+
         internal/singleflight                                        from net
         internal/stringslite                                         from embed+
+        internal/sync                                                from sync+
         internal/syscall/execenv                                     from os+
-  LD    internal/syscall/unix                                        from crypto/rand+
-   W    internal/syscall/windows                                     from crypto/rand+
+  LD    internal/syscall/unix                                        from crypto/internal/sysrand+
+   W    internal/syscall/windows                                     from crypto/internal/sysrand+
    W    internal/syscall/windows/registry                            from mime+
    W    internal/syscall/windows/sysdll                              from internal/syscall/windows+
         internal/testlog                                             from os
         internal/unsafeheader                                        from internal/reflectlite+
-        internal/weak                                                from unique
         io                                                           from archive/tar+
         io/fs                                                        from archive/tar+
         io/ioutil                                                    from github.com/aws/aws-sdk-go-v2/aws/protocol/query+
@@ -1191,7 +1218,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         net/netip                                                    from github.com/gaissmai/bart+
         net/textproto                                                from github.com/aws/aws-sdk-go-v2/aws/signer/v4+
         net/url                                                      from crypto/x509+
-        os                                                           from crypto/rand+
+        os                                                           from crypto/internal/sysrand+
         os/exec                                                      from github.com/aws/aws-sdk-go-v2/credentials/processcreds+
         os/signal                                                    from sigs.k8s.io/controller-runtime/pkg/manager/signals
         os/user                                                      from archive/tar+
@@ -1202,8 +1229,6 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         regexp/syntax                                                from regexp
         runtime                                                      from archive/tar+
         runtime/debug                                                from github.com/aws/aws-sdk-go-v2/internal/sync/singleflight+
-        runtime/internal/math                                        from runtime
-        runtime/internal/sys                                         from runtime
         runtime/metrics                                              from github.com/prometheus/client_golang/prometheus+
         runtime/pprof                                                from net/http/pprof+
         runtime/trace                                                from net/http/pprof
@@ -1223,3 +1248,4 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         unicode/utf8                                                 from bufio+
         unique                                                       from net/netip
         unsafe                                                       from bytes+
+        weak                                                         from unique

cmd/k8s-operator/ingress-for-pg.go

@@ -26,7 +26,7 @@ import (
 	"k8s.io/client-go/tools/record"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
-	"tailscale.com/client/tailscale"
+	"tailscale.com/internal/client/tailscale"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	tsoperator "tailscale.com/k8s-operator"
@@ -186,7 +186,7 @@ func (a *IngressPGReconciler) maybeProvision(ctx context.Context, hostname strin
 	}
 	dnsName := hostname + "." + tcd
 	serviceName := tailcfg.ServiceName("svc:" + hostname)
-	existingVIPSvc, err := a.tsClient.getVIPService(ctx, serviceName)
+	existingVIPSvc, err := a.tsClient.GetVIPService(ctx, serviceName)
 	// TODO(irbekrm): here and when creating the VIPService, verify if the error is not terminal (and therefore
 	// should not be reconciled). For example, if the hostname is already a hostname of a Tailscale node, the GET
 	// here will fail.
@@ -269,7 +269,7 @@ func (a *IngressPGReconciler) maybeProvision(ctx context.Context, hostname strin
 		vipPorts = append(vipPorts, "80")
 	}
 
-	vipSvc := &VIPService{
+	vipSvc := &tailscale.VIPService{
 		Name:    serviceName,
 		Tags:    tags,
 		Ports:   vipPorts,
@@ -282,7 +282,7 @@ func (a *IngressPGReconciler) maybeProvision(ctx context.Context, hostname strin
 		!reflect.DeepEqual(vipSvc.Tags, existingVIPSvc.Tags) ||
 		!reflect.DeepEqual(vipSvc.Ports, existingVIPSvc.Ports) {
 		logger.Infof("Ensuring VIPService %q exists and is up to date", hostname)
-		if err := a.tsClient.createOrUpdateVIPService(ctx, vipSvc); err != nil {
+		if err := a.tsClient.CreateOrUpdateVIPService(ctx, vipSvc); err != nil {
 			logger.Infof("error creating VIPService: %v", err)
 			return fmt.Errorf("error creating VIPService: %w", err)
 		}
@@ -361,7 +361,7 @@ func (a *IngressPGReconciler) maybeCleanupProxyGroup(ctx context.Context, proxyG
 			}
 			if isVIPServiceForAnyIngress(svc) {
 				logger.Infof("cleaning up orphaned VIPService %q", vipServiceName)
-				if err := a.tsClient.deleteVIPService(ctx, vipServiceName); err != nil {
+				if err := a.tsClient.DeleteVIPService(ctx, vipServiceName); err != nil {
 					errResp := &tailscale.ErrResponse{}
 					if !errors.As(err, &errResp) || errResp.Status != http.StatusNotFound {
 						return fmt.Errorf("deleting VIPService %q: %w", vipServiceName, err)
@@ -509,8 +509,8 @@ func (a *IngressPGReconciler) shouldExpose(ing *networkingv1.Ingress) bool {
 	return isTSIngress && pgAnnot != ""
 }
 
-func (a *IngressPGReconciler) getVIPService(ctx context.Context, name tailcfg.ServiceName, logger *zap.SugaredLogger) (*VIPService, error) {
-	svc, err := a.tsClient.getVIPService(ctx, name)
+func (a *IngressPGReconciler) getVIPService(ctx context.Context, name tailcfg.ServiceName, logger *zap.SugaredLogger) (*tailscale.VIPService, error) {
+	svc, err := a.tsClient.GetVIPService(ctx, name)
 	if err != nil {
 		errResp := &tailscale.ErrResponse{}
 		if ok := errors.As(err, errResp); ok && errResp.Status != http.StatusNotFound {
@@ -521,14 +521,14 @@ func (a *IngressPGReconciler) getVIPService(ctx context.Context, name tailcfg.Se
 	return svc, nil
 }
 
-func isVIPServiceForIngress(svc *VIPService, ing *networkingv1.Ingress) bool {
+func isVIPServiceForIngress(svc *tailscale.VIPService, ing *networkingv1.Ingress) bool {
 	if svc == nil || ing == nil {
 		return false
 	}
 	return strings.EqualFold(svc.Comment, fmt.Sprintf(VIPSvcOwnerRef, ing.UID))
 }
 
-func isVIPServiceForAnyIngress(svc *VIPService) bool {
+func isVIPServiceForAnyIngress(svc *tailscale.VIPService) bool {
 	if svc == nil {
 		return false
 	}
@@ -593,7 +593,7 @@ func (a *IngressPGReconciler) deleteVIPServiceIfExists(ctx context.Context, name
 	}
 
 	logger.Infof("Deleting VIPService %q", name)
-	if err = a.tsClient.deleteVIPService(ctx, name); err != nil {
+	if err = a.tsClient.DeleteVIPService(ctx, name); err != nil {
 		return fmt.Errorf("error deleting VIPService: %w", err)
 	}
 	return nil

cmd/k8s-operator/ingress-for-pg_test.go

@@ -70,7 +70,7 @@ func TestIngressPGReconciler(t *testing.T) {
 	expectReconciled(t, ingPGR, "default", "test-ingress")
 
 	// Verify VIPService uses custom tags
-	vipSvc, err := ft.getVIPService(context.Background(), "svc:my-svc")
+	vipSvc, err := ft.GetVIPService(context.Background(), "svc:my-svc")
 	if err != nil {
 		t.Fatalf("getting VIPService: %v", err)
 	}
@@ -398,7 +398,7 @@ func TestIngressPGReconciler_HTTPEndpoint(t *testing.T) {
 
 func verifyVIPService(t *testing.T, ft *fakeTSClient, serviceName string, wantPorts []string) {
 	t.Helper()
-	vipSvc, err := ft.getVIPService(context.Background(), tailcfg.ServiceName(serviceName))
+	vipSvc, err := ft.GetVIPService(context.Background(), tailcfg.ServiceName(serviceName))
 	if err != nil {
 		t.Fatalf("getting VIPService %q: %v", serviceName, err)
 	}

cmd/k8s-operator/testutils_test.go

@@ -28,7 +28,7 @@ import (
 	"k8s.io/client-go/tools/record"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
-	"tailscale.com/client/tailscale"
+	"tailscale.com/internal/client/tailscale"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	tsapi "tailscale.com/k8s-operator/apis/v1alpha1"
@@ -768,7 +768,7 @@ type fakeTSClient struct {
 	sync.Mutex
 	keyRequests []tailscale.KeyCapabilities
 	deleted     []string
-	vipServices map[tailcfg.ServiceName]*VIPService
+	vipServices map[tailcfg.ServiceName]*tailscale.VIPService
 }
 type fakeTSNetServer struct {
 	certDomains []string
@@ -875,7 +875,7 @@ func removeAuthKeyIfExistsModifier(t *testing.T) func(s *corev1.Secret) {
 	}
 }
 
-func (c *fakeTSClient) getVIPService(ctx context.Context, name tailcfg.ServiceName) (*VIPService, error) {
+func (c *fakeTSClient) GetVIPService(ctx context.Context, name tailcfg.ServiceName) (*tailscale.VIPService, error) {
 	c.Lock()
 	defer c.Unlock()
 	if c.vipServices == nil {
@@ -888,17 +888,17 @@ func (c *fakeTSClient) getVIPService(ctx context.Context, name tailcfg.ServiceNa
 	return svc, nil
 }
 
-func (c *fakeTSClient) createOrUpdateVIPService(ctx context.Context, svc *VIPService) error {
+func (c *fakeTSClient) CreateOrUpdateVIPService(ctx context.Context, svc *tailscale.VIPService) error {
 	c.Lock()
 	defer c.Unlock()
 	if c.vipServices == nil {
-		c.vipServices = make(map[tailcfg.ServiceName]*VIPService)
+		c.vipServices = make(map[tailcfg.ServiceName]*tailscale.VIPService)
 	}
 	c.vipServices[svc.Name] = svc
 	return nil
 }
 
-func (c *fakeTSClient) deleteVIPService(ctx context.Context, name tailcfg.ServiceName) error {
+func (c *fakeTSClient) DeleteVIPService(ctx context.Context, name tailcfg.ServiceName) error {
 	c.Lock()
 	defer c.Unlock()
 	if c.vipServices != nil {

cmd/k8s-operator/tsclient.go

@@ -6,19 +6,13 @@
 package main
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
-	"net/http"
-	"net/url"
 	"os"
 
 	"golang.org/x/oauth2/clientcredentials"
 	"tailscale.com/internal/client/tailscale"
 	"tailscale.com/tailcfg"
-	"tailscale.com/util/httpm"
 )
 
 // defaultTailnet is a value that can be used in Tailscale API calls instead of tailnet name to indicate that the API
@@ -45,141 +39,14 @@ func newTSClient(ctx context.Context, clientIDPath, clientSecretPath string) (ts
 	c := tailscale.NewClient(defaultTailnet, nil)
 	c.UserAgent = "tailscale-k8s-operator"
 	c.HTTPClient = credentials.Client(ctx)
-	tsc := &tsClientImpl{
-		Client:  c,
-		baseURL: defaultBaseURL,
-		tailnet: defaultTailnet,
-	}
-	return tsc, nil
+	return c, nil
 }
 
 type tsClient interface {
 	CreateKey(ctx context.Context, caps tailscale.KeyCapabilities) (string, *tailscale.Key, error)
 	Device(ctx context.Context, deviceID string, fields *tailscale.DeviceFieldsOpts) (*tailscale.Device, error)
 	DeleteDevice(ctx context.Context, nodeStableID string) error
-	getVIPService(ctx context.Context, name tailcfg.ServiceName) (*VIPService, error)
-	createOrUpdateVIPService(ctx context.Context, svc *VIPService) error
-	deleteVIPService(ctx context.Context, name tailcfg.ServiceName) error
-}
-
-type tsClientImpl struct {
-	*tailscale.Client
-	baseURL string
-	tailnet string
-}
-
-// VIPService is a Tailscale VIPService with Tailscale API JSON representation.
-type VIPService struct {
-	// Name is a VIPService name in form svc:<leftmost-label-of-service-DNS-name>.
-	Name tailcfg.ServiceName `json:"name,omitempty"`
-	// Addrs are the IP addresses of the VIP Service. There are two addresses:
-	// the first is IPv4 and the second is IPv6.
-	// When creating a new VIP Service, the IP addresses are optional: if no
-	// addresses are specified then they will be selected. If an IPv4 address is
-	// specified at index 0, then that address will attempt to be used. An IPv6
-	// address can not be specified upon creation.
-	Addrs []string `json:"addrs,omitempty"`
-	// Comment is an optional text string for display in the admin panel.
-	Comment string `json:"comment,omitempty"`
-	// Ports are the ports of a VIPService that will be configured via Tailscale serve config.
-	// If set, any node wishing to advertise this VIPService must have this port configured via Tailscale serve.
-	Ports []string `json:"ports,omitempty"`
-	// Tags are optional ACL tags that will be applied to the VIPService.
-	Tags []string `json:"tags,omitempty"`
-}
-
-// GetVIPServiceByName retrieves a VIPService by its name. It returns 404 if the VIPService is not found.
-func (c *tsClientImpl) getVIPService(ctx context.Context, name tailcfg.ServiceName) (*VIPService, error) {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/vip-services/%s", c.baseURL, c.tailnet, url.PathEscape(name.String()))
-	req, err := http.NewRequestWithContext(ctx, httpm.GET, path, nil)
-	if err != nil {
-		return nil, fmt.Errorf("error creating new HTTP request: %w", err)
-	}
-	b, resp, err := c.sendRequest(req)
-	if err != nil {
-		return nil, fmt.Errorf("error making Tailsale API request: %w", err)
-	}
-	// If status code was not successful, return the error.
-	// TODO: Change the check for the StatusCode to include other 2XX success codes.
-	if resp.StatusCode != http.StatusOK {
-		return nil, handleErrorResponse(b, resp)
-	}
-	svc := &VIPService{}
-	if err := json.Unmarshal(b, svc); err != nil {
-		return nil, err
-	}
-	return svc, nil
-}
-
-// createOrUpdateVIPService creates or updates a VIPService by its name. Caller must ensure that, if the
-// VIPService already exists, the VIPService is fetched first to ensure that any auto-allocated IP addresses are not
-// lost during the update. If the VIPService was created without any IP addresses explicitly set (so that they were
-// auto-allocated by Tailscale) any subsequent request to this function that does not set any IP addresses will error.
-func (c *tsClientImpl) createOrUpdateVIPService(ctx context.Context, svc *VIPService) error {
-	data, err := json.Marshal(svc)
-	if err != nil {
-		return err
-	}
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/vip-services/%s", c.baseURL, c.tailnet, url.PathEscape(svc.Name.String()))
-	req, err := http.NewRequestWithContext(ctx, httpm.PUT, path, bytes.NewBuffer(data))
-	if err != nil {
-		return fmt.Errorf("error creating new HTTP request: %w", err)
-	}
-	b, resp, err := c.sendRequest(req)
-	if err != nil {
-		return fmt.Errorf("error making Tailscale API request: %w", err)
-	}
-	// If status code was not successful, return the error.
-	// TODO: Change the check for the StatusCode to include other 2XX success codes.
-	if resp.StatusCode != http.StatusOK {
-		return handleErrorResponse(b, resp)
-	}
-	return nil
-}
-
-// DeleteVIPServiceByName deletes a VIPService by its name. It returns an error if the VIPService
-// does not exist or if the deletion fails.
-func (c *tsClientImpl) deleteVIPService(ctx context.Context, name tailcfg.ServiceName) error {
-	path := fmt.Sprintf("%s/api/v2/tailnet/%s/vip-services/%s", c.baseURL, c.tailnet, url.PathEscape(name.String()))
-	req, err := http.NewRequestWithContext(ctx, httpm.DELETE, path, nil)
-	if err != nil {
-		return fmt.Errorf("error creating new HTTP request: %w", err)
-	}
-	b, resp, err := c.sendRequest(req)
-	if err != nil {
-		return fmt.Errorf("error making Tailscale API request: %w", err)
-	}
-	// If status code was not successful, return the error.
-	if resp.StatusCode != http.StatusOK {
-		return handleErrorResponse(b, resp)
-	}
-	return nil
-}
-
-// sendRequest add the authentication key to the request and sends it. It
-// receives the response and reads up to 10MB of it.
-func (c *tsClientImpl) sendRequest(req *http.Request) ([]byte, *http.Response, error) {
-	resp, err := c.Do(req)
-	if err != nil {
-		return nil, resp, fmt.Errorf("error actually doing request: %w", err)
-	}
-	defer resp.Body.Close()
-
-	// Read response
-	b, err := io.ReadAll(resp.Body)
-	if err != nil {
-		err = fmt.Errorf("error reading response body: %v", err)
-	}
-	return b, resp, err
-}
-
-// handleErrorResponse decodes the error message from the server and returns
-// an ErrResponse from it.
-func handleErrorResponse(b []byte, resp *http.Response) error {
-	var errResp tailscale.ErrResponse
-	if err := json.Unmarshal(b, &errResp); err != nil {
-		return err
-	}
-	errResp.Status = resp.StatusCode
-	return errResp
+	GetVIPService(ctx context.Context, name tailcfg.ServiceName) (*tailscale.VIPService, error)
+	CreateOrUpdateVIPService(ctx context.Context, svc *tailscale.VIPService) error
+	DeleteVIPService(ctx context.Context, name tailcfg.ServiceName) error
 }

cmd/stund/depaware.txt

@@ -88,13 +88,11 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         golang.org/x/crypto/cryptobyte                               from crypto/ecdsa+
         golang.org/x/crypto/cryptobyte/asn1                          from crypto/ecdsa+
         golang.org/x/crypto/curve25519                               from golang.org/x/crypto/nacl/box+
-        golang.org/x/crypto/hkdf                                     from crypto/tls+
         golang.org/x/crypto/internal/alias                           from golang.org/x/crypto/chacha20+
         golang.org/x/crypto/internal/poly1305                        from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
-        golang.org/x/crypto/sha3                                     from crypto/internal/mlkem768+
         golang.org/x/net/dns/dnsmessage                              from net+
         golang.org/x/net/http/httpguts                               from net/http
         golang.org/x/net/http/httpproxy                              from net/http
@@ -116,7 +114,7 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         container/list                                               from crypto/tls+
         context                                                      from crypto/tls+
         crypto                                                       from crypto/ecdh+
-        crypto/aes                                                   from crypto/ecdsa+
+        crypto/aes                                                   from crypto/internal/hpke+
         crypto/cipher                                                from crypto/aes+
         crypto/des                                                   from crypto/tls+
         crypto/dsa                                                   from crypto/x509
@@ -124,32 +122,59 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         crypto/ecdsa                                                 from crypto/tls+
         crypto/ed25519                                               from crypto/tls+
         crypto/elliptic                                              from crypto/ecdsa+
-        crypto/hmac                                                  from crypto/tls+
-        crypto/internal/alias                                        from crypto/aes+
-        crypto/internal/bigmod                                       from crypto/ecdsa+
+        crypto/hmac                                                  from crypto/tls
         crypto/internal/boring                                       from crypto/aes+
         crypto/internal/boring/bbig                                  from crypto/ecdsa+
         crypto/internal/boring/sig                                   from crypto/internal/boring
-        crypto/internal/edwards25519                                 from crypto/ed25519
-        crypto/internal/edwards25519/field                           from crypto/ecdh+
+        crypto/internal/entropy                                      from crypto/internal/fips140/drbg
+        crypto/internal/fips140                                      from crypto/internal/fips140/aes+
+        crypto/internal/fips140/aes                                  from crypto/aes+
+        crypto/internal/fips140/aes/gcm                              from crypto/cipher+
+        crypto/internal/fips140/alias                                from crypto/cipher+
+        crypto/internal/fips140/bigmod                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/check                                from crypto/internal/fips140/aes+
+        crypto/internal/fips140/drbg                                 from crypto/internal/fips140/aes/gcm+
+        crypto/internal/fips140/ecdh                                 from crypto/ecdh
+        crypto/internal/fips140/ecdsa                                from crypto/ecdsa
+        crypto/internal/fips140/ed25519                              from crypto/ed25519
+        crypto/internal/fips140/edwards25519                         from crypto/internal/fips140/ed25519
+        crypto/internal/fips140/edwards25519/field                   from crypto/ecdh+
+        crypto/internal/fips140/hkdf                                 from crypto/internal/fips140/tls13+
+        crypto/internal/fips140/hmac                                 from crypto/hmac+
+        crypto/internal/fips140/mlkem                                from crypto/tls
+        crypto/internal/fips140/nistec                               from crypto/elliptic+
+        crypto/internal/fips140/nistec/fiat                          from crypto/internal/fips140/nistec
+        crypto/internal/fips140/rsa                                  from crypto/rsa
+        crypto/internal/fips140/sha256                               from crypto/internal/fips140/check+
+        crypto/internal/fips140/sha3                                 from crypto/internal/fips140/hmac+
+        crypto/internal/fips140/sha512                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/subtle                               from crypto/internal/fips140/aes+
+        crypto/internal/fips140/tls12                                from crypto/tls
+        crypto/internal/fips140/tls13                                from crypto/tls
+        crypto/internal/fips140deps/byteorder                        from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/cpu                              from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/godebug                          from crypto/internal/fips140+
+        crypto/internal/fips140hash                                  from crypto/ecdsa+
+        crypto/internal/fips140only                                  from crypto/cipher+
         crypto/internal/hpke                                         from crypto/tls
-        crypto/internal/mlkem768                                     from crypto/tls
-        crypto/internal/nistec                                       from crypto/ecdh+
-        crypto/internal/nistec/fiat                                  from crypto/internal/nistec
+        crypto/internal/impl                                         from crypto/internal/fips140/aes+
         crypto/internal/randutil                                     from crypto/dsa+
+        crypto/internal/sysrand                                      from crypto/internal/entropy+
         crypto/md5                                                   from crypto/tls+
         crypto/rand                                                  from crypto/ed25519+
         crypto/rc4                                                   from crypto/tls
         crypto/rsa                                                   from crypto/tls+
         crypto/sha1                                                  from crypto/tls+
         crypto/sha256                                                from crypto/tls+
+        crypto/sha3                                                  from crypto/internal/fips140hash
         crypto/sha512                                                from crypto/ecdsa+
-        crypto/subtle                                                from crypto/aes+
+        crypto/subtle                                                from crypto/cipher+
         crypto/tls                                                   from net/http+
+        crypto/tls/internal/fips140tls                               from crypto/tls
         crypto/x509                                                  from crypto/tls
    D    crypto/x509/internal/macos                                   from crypto/x509
         crypto/x509/pkix                                             from crypto/x509
-        embed                                                        from crypto/internal/nistec+
+        embed                                                        from google.golang.org/protobuf/internal/editiondefaults+
         encoding                                                     from encoding/json+
         encoding/asn1                                                from crypto/x509+
         encoding/base32                                              from github.com/go-json-experiment/json
@@ -169,23 +194,22 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         hash/maphash                                                 from go4.org/mem
         html                                                         from net/http/pprof+
         internal/abi                                                 from crypto/x509/internal/macos+
-        internal/asan                                                from syscall
+        internal/asan                                                from syscall+
         internal/bisect                                              from internal/godebug
         internal/bytealg                                             from bytes+
-        internal/byteorder                                           from crypto/aes+
+        internal/byteorder                                           from crypto/cipher+
         internal/chacha8rand                                         from math/rand/v2+
-        internal/concurrent                                          from unique
         internal/coverage/rtcov                                      from runtime
-        internal/cpu                                                 from crypto/aes+
+        internal/cpu                                                 from crypto/internal/fips140deps/cpu+
         internal/filepathlite                                        from os+
         internal/fmtsort                                             from fmt
-        internal/goarch                                              from crypto/aes+
+        internal/goarch                                              from crypto/internal/fips140deps/cpu+
         internal/godebug                                             from crypto/tls+
         internal/godebugs                                            from internal/godebug+
-        internal/goexperiment                                        from runtime
+        internal/goexperiment                                        from runtime+
         internal/goos                                                from crypto/x509+
         internal/itoa                                                from internal/poll+
-        internal/msan                                                from syscall
+        internal/msan                                                from syscall+
         internal/nettrace                                            from net+
         internal/oserror                                             from io/fs+
         internal/poll                                                from net+
@@ -195,17 +219,20 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         internal/reflectlite                                         from context+
         internal/runtime/atomic                                      from internal/runtime/exithook+
         internal/runtime/exithook                                    from runtime
+        internal/runtime/maps                                        from reflect+
+        internal/runtime/math                                        from internal/runtime/maps+
+        internal/runtime/sys                                         from crypto/subtle+
    L    internal/runtime/syscall                                     from runtime+
         internal/singleflight                                        from net
         internal/stringslite                                         from embed+
+        internal/sync                                                from sync+
         internal/syscall/execenv                                     from os
-  LD    internal/syscall/unix                                        from crypto/rand+
-   W    internal/syscall/windows                                     from crypto/rand+
+  LD    internal/syscall/unix                                        from crypto/internal/sysrand+
+   W    internal/syscall/windows                                     from crypto/internal/sysrand+
    W    internal/syscall/windows/registry                            from mime+
    W    internal/syscall/windows/sysdll                              from internal/syscall/windows+
         internal/testlog                                             from os
         internal/unsafeheader                                        from internal/reflectlite+
-        internal/weak                                                from unique
         io                                                           from bufio+
         io/fs                                                        from crypto/x509+
         iter                                                         from maps+
@@ -216,7 +243,7 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+
         math/rand                                                    from math/big+
-        math/rand/v2                                                 from internal/concurrent+
+        math/rand/v2                                                 from crypto/ecdsa+
         mime                                                         from github.com/prometheus/common/expfmt+
         mime/multipart                                               from net/http
         mime/quotedprintable                                         from mime/multipart
@@ -229,17 +256,15 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         net/netip                                                    from go4.org/netipx+
         net/textproto                                                from golang.org/x/net/http/httpguts+
         net/url                                                      from crypto/x509+
-        os                                                           from crypto/rand+
+        os                                                           from crypto/internal/sysrand+
         os/signal                                                    from tailscale.com/cmd/stund
         path                                                         from github.com/prometheus/client_golang/prometheus/internal+
         path/filepath                                                from crypto/x509+
         reflect                                                      from crypto/x509+
         regexp                                                       from github.com/prometheus/client_golang/prometheus/internal+
         regexp/syntax                                                from regexp
-        runtime                                                      from crypto/internal/nistec+
+        runtime                                                      from crypto/internal/fips140+
         runtime/debug                                                from github.com/prometheus/client_golang/prometheus+
-        runtime/internal/math                                        from runtime
-        runtime/internal/sys                                         from runtime
         runtime/metrics                                              from github.com/prometheus/client_golang/prometheus+
         runtime/pprof                                                from net/http/pprof
         runtime/trace                                                from net/http/pprof
@@ -249,7 +274,7 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         strings                                                      from bufio+
         sync                                                         from compress/flate+
         sync/atomic                                                  from context+
-        syscall                                                      from crypto/rand+
+        syscall                                                      from crypto/internal/sysrand+
         text/tabwriter                                               from runtime/pprof
         time                                                         from compress/gzip+
         unicode                                                      from bytes+
@@ -257,3 +282,4 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         unicode/utf8                                                 from bufio+
         unique                                                       from net/netip
         unsafe                                                       from bytes+
+        weak                                                         from unique

cmd/tailscale/depaware.txt

@@ -195,14 +195,13 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         golang.org/x/crypto/cryptobyte                               from crypto/ecdsa+
         golang.org/x/crypto/cryptobyte/asn1                          from crypto/ecdsa+
         golang.org/x/crypto/curve25519                               from golang.org/x/crypto/nacl/box+
-        golang.org/x/crypto/hkdf                                     from crypto/tls+
+        golang.org/x/crypto/hkdf                                     from tailscale.com/control/controlbase
         golang.org/x/crypto/internal/alias                           from golang.org/x/crypto/chacha20+
         golang.org/x/crypto/internal/poly1305                        from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/pbkdf2                                   from software.sslmate.com/src/go-pkcs12
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
-        golang.org/x/crypto/sha3                                     from crypto/internal/mlkem768+
    W    golang.org/x/exp/constraints                                 from github.com/dblohm7/wingoes/pe+
         golang.org/x/exp/maps                                        from tailscale.com/util/syspolicy/internal/metrics+
         golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
@@ -246,7 +245,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         container/list                                               from crypto/tls+
         context                                                      from crypto/tls+
         crypto                                                       from crypto/ecdh+
-        crypto/aes                                                   from crypto/ecdsa+
+        crypto/aes                                                   from crypto/internal/hpke+
         crypto/cipher                                                from crypto/aes+
         crypto/des                                                   from crypto/tls+
         crypto/dsa                                                   from crypto/x509
@@ -255,34 +254,61 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         crypto/ed25519                                               from crypto/tls+
         crypto/elliptic                                              from crypto/ecdsa+
         crypto/hmac                                                  from crypto/tls+
-        crypto/internal/alias                                        from crypto/aes+
-        crypto/internal/bigmod                                       from crypto/ecdsa+
         crypto/internal/boring                                       from crypto/aes+
         crypto/internal/boring/bbig                                  from crypto/ecdsa+
         crypto/internal/boring/sig                                   from crypto/internal/boring
-        crypto/internal/edwards25519                                 from crypto/ed25519
-        crypto/internal/edwards25519/field                           from crypto/ecdh+
+        crypto/internal/entropy                                      from crypto/internal/fips140/drbg
+        crypto/internal/fips140                                      from crypto/internal/fips140/aes+
+        crypto/internal/fips140/aes                                  from crypto/aes+
+        crypto/internal/fips140/aes/gcm                              from crypto/cipher+
+        crypto/internal/fips140/alias                                from crypto/cipher+
+        crypto/internal/fips140/bigmod                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/check                                from crypto/internal/fips140/aes+
+        crypto/internal/fips140/drbg                                 from crypto/internal/fips140/aes/gcm+
+        crypto/internal/fips140/ecdh                                 from crypto/ecdh
+        crypto/internal/fips140/ecdsa                                from crypto/ecdsa
+        crypto/internal/fips140/ed25519                              from crypto/ed25519
+        crypto/internal/fips140/edwards25519                         from crypto/internal/fips140/ed25519
+        crypto/internal/fips140/edwards25519/field                   from crypto/ecdh+
+        crypto/internal/fips140/hkdf                                 from crypto/internal/fips140/tls13+
+        crypto/internal/fips140/hmac                                 from crypto/hmac+
+        crypto/internal/fips140/mlkem                                from crypto/tls
+        crypto/internal/fips140/nistec                               from crypto/elliptic+
+        crypto/internal/fips140/nistec/fiat                          from crypto/internal/fips140/nistec
+        crypto/internal/fips140/rsa                                  from crypto/rsa
+        crypto/internal/fips140/sha256                               from crypto/internal/fips140/check+
+        crypto/internal/fips140/sha3                                 from crypto/internal/fips140/hmac+
+        crypto/internal/fips140/sha512                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/subtle                               from crypto/internal/fips140/aes+
+        crypto/internal/fips140/tls12                                from crypto/tls
+        crypto/internal/fips140/tls13                                from crypto/tls
+        crypto/internal/fips140deps/byteorder                        from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/cpu                              from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/godebug                          from crypto/internal/fips140+
+        crypto/internal/fips140hash                                  from crypto/ecdsa+
+        crypto/internal/fips140only                                  from crypto/cipher+
         crypto/internal/hpke                                         from crypto/tls
-        crypto/internal/mlkem768                                     from crypto/tls
-        crypto/internal/nistec                                       from crypto/ecdh+
-        crypto/internal/nistec/fiat                                  from crypto/internal/nistec
+        crypto/internal/impl                                         from crypto/internal/fips140/aes+
         crypto/internal/randutil                                     from crypto/dsa+
+        crypto/internal/sysrand                                      from crypto/internal/entropy+
         crypto/md5                                                   from crypto/tls+
         crypto/rand                                                  from crypto/ed25519+
         crypto/rc4                                                   from crypto/tls
         crypto/rsa                                                   from crypto/tls+
         crypto/sha1                                                  from crypto/tls+
         crypto/sha256                                                from crypto/tls+
+        crypto/sha3                                                  from crypto/internal/fips140hash
         crypto/sha512                                                from crypto/ecdsa+
-        crypto/subtle                                                from crypto/aes+
+        crypto/subtle                                                from crypto/cipher+
         crypto/tls                                                   from github.com/miekg/dns+
+        crypto/tls/internal/fips140tls                               from crypto/tls
         crypto/x509                                                  from crypto/tls+
    D    crypto/x509/internal/macos                                   from crypto/x509
         crypto/x509/pkix                                             from crypto/x509+
   DW    database/sql/driver                                          from github.com/google/uuid
    W    debug/dwarf                                                  from debug/pe
    W    debug/pe                                                     from github.com/dblohm7/wingoes/pe
-        embed                                                        from crypto/internal/nistec+
+        embed                                                        from github.com/peterbourgon/ff/v3+
         encoding                                                     from encoding/gob+
         encoding/asn1                                                from crypto/x509+
         encoding/base32                                              from github.com/fxamacker/cbor/v2+
@@ -307,23 +333,22 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         image/color                                                  from github.com/skip2/go-qrcode+
         image/png                                                    from github.com/skip2/go-qrcode
         internal/abi                                                 from crypto/x509/internal/macos+
-        internal/asan                                                from syscall
+        internal/asan                                                from syscall+
         internal/bisect                                              from internal/godebug
         internal/bytealg                                             from bytes+
-        internal/byteorder                                           from crypto/aes+
+        internal/byteorder                                           from crypto/cipher+
         internal/chacha8rand                                         from math/rand/v2+
-        internal/concurrent                                          from unique
         internal/coverage/rtcov                                      from runtime
-        internal/cpu                                                 from crypto/aes+
+        internal/cpu                                                 from crypto/internal/fips140deps/cpu+
         internal/filepathlite                                        from os+
         internal/fmtsort                                             from fmt+
-        internal/goarch                                              from crypto/aes+
+        internal/goarch                                              from crypto/internal/fips140deps/cpu+
         internal/godebug                                             from archive/tar+
         internal/godebugs                                            from internal/godebug+
-        internal/goexperiment                                        from runtime
+        internal/goexperiment                                        from runtime+
         internal/goos                                                from crypto/x509+
         internal/itoa                                                from internal/poll+
-        internal/msan                                                from syscall
+        internal/msan                                                from syscall+
         internal/nettrace                                            from net+
         internal/oserror                                             from io/fs+
         internal/poll                                                from net+
@@ -332,18 +357,21 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         internal/reflectlite                                         from context+
         internal/runtime/atomic                                      from internal/runtime/exithook+
         internal/runtime/exithook                                    from runtime
+        internal/runtime/maps                                        from reflect+
+        internal/runtime/math                                        from internal/runtime/maps+
+        internal/runtime/sys                                         from crypto/subtle+
    L    internal/runtime/syscall                                     from runtime+
         internal/saferio                                             from debug/pe+
         internal/singleflight                                        from net
         internal/stringslite                                         from embed+
+        internal/sync                                                from sync+
         internal/syscall/execenv                                     from os+
-  LD    internal/syscall/unix                                        from crypto/rand+
-   W    internal/syscall/windows                                     from crypto/rand+
+  LD    internal/syscall/unix                                        from crypto/internal/sysrand+
+   W    internal/syscall/windows                                     from crypto/internal/sysrand+
    W    internal/syscall/windows/registry                            from mime+
    W    internal/syscall/windows/sysdll                              from internal/syscall/windows+
         internal/testlog                                             from os
         internal/unsafeheader                                        from internal/reflectlite+
-        internal/weak                                                from unique
         io                                                           from archive/tar+
         io/fs                                                        from archive/tar+
         io/ioutil                                                    from github.com/mitchellh/go-ps+
@@ -369,7 +397,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         net/netip                                                    from go4.org/netipx+
         net/textproto                                                from golang.org/x/net/http/httpguts+
         net/url                                                      from crypto/x509+
-        os                                                           from crypto/rand+
+        os                                                           from crypto/internal/sysrand+
         os/exec                                                      from github.com/coreos/go-iptables/iptables+
         os/signal                                                    from tailscale.com/cmd/tailscale/cli
         os/user                                                      from archive/tar+
@@ -380,8 +408,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         regexp/syntax                                                from regexp
         runtime                                                      from archive/tar+
         runtime/debug                                                from tailscale.com+
-        runtime/internal/math                                        from runtime
-        runtime/internal/sys                                         from runtime
         slices                                                       from tailscale.com/client/web+
         sort                                                         from compress/flate+
         strconv                                                      from archive/tar+
@@ -398,3 +424,4 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         unicode/utf8                                                 from bufio+
         unique                                                       from net/netip
         unsafe                                                       from bytes+
+        weak                                                         from unique

cmd/tailscaled/depaware.txt

@@ -449,14 +449,13 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         golang.org/x/crypto/cryptobyte                               from crypto/ecdsa+
         golang.org/x/crypto/cryptobyte/asn1                          from crypto/ecdsa+
         golang.org/x/crypto/curve25519                               from golang.org/x/crypto/ssh+
-        golang.org/x/crypto/hkdf                                     from crypto/tls+
+        golang.org/x/crypto/hkdf                                     from tailscale.com/control/controlbase
         golang.org/x/crypto/internal/alias                           from golang.org/x/crypto/chacha20+
         golang.org/x/crypto/internal/poly1305                        from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/poly1305                                 from github.com/tailscale/wireguard-go/device
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
-        golang.org/x/crypto/sha3                                     from crypto/internal/mlkem768+
   LD    golang.org/x/crypto/ssh                                      from github.com/pkg/sftp+
   LD    golang.org/x/crypto/ssh/internal/bcrypt_pbkdf                from golang.org/x/crypto/ssh
         golang.org/x/exp/constraints                                 from github.com/dblohm7/wingoes/pe+
@@ -504,7 +503,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         container/list                                               from crypto/tls+
         context                                                      from crypto/tls+
         crypto                                                       from crypto/ecdh+
-        crypto/aes                                                   from crypto/ecdsa+
+        crypto/aes                                                   from crypto/internal/hpke+
         crypto/cipher                                                from crypto/aes+
         crypto/des                                                   from crypto/tls+
         crypto/dsa                                                   from crypto/x509+
@@ -513,34 +512,61 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         crypto/ed25519                                               from crypto/tls+
         crypto/elliptic                                              from crypto/ecdsa+
         crypto/hmac                                                  from crypto/tls+
-        crypto/internal/alias                                        from crypto/aes+
-        crypto/internal/bigmod                                       from crypto/ecdsa+
         crypto/internal/boring                                       from crypto/aes+
         crypto/internal/boring/bbig                                  from crypto/ecdsa+
         crypto/internal/boring/sig                                   from crypto/internal/boring
-        crypto/internal/edwards25519                                 from crypto/ed25519
-        crypto/internal/edwards25519/field                           from crypto/ecdh+
+        crypto/internal/entropy                                      from crypto/internal/fips140/drbg
+        crypto/internal/fips140                                      from crypto/internal/fips140/aes+
+        crypto/internal/fips140/aes                                  from crypto/aes+
+        crypto/internal/fips140/aes/gcm                              from crypto/cipher+
+        crypto/internal/fips140/alias                                from crypto/cipher+
+        crypto/internal/fips140/bigmod                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/check                                from crypto/internal/fips140/aes+
+        crypto/internal/fips140/drbg                                 from crypto/internal/fips140/aes/gcm+
+        crypto/internal/fips140/ecdh                                 from crypto/ecdh
+        crypto/internal/fips140/ecdsa                                from crypto/ecdsa
+        crypto/internal/fips140/ed25519                              from crypto/ed25519
+        crypto/internal/fips140/edwards25519                         from crypto/internal/fips140/ed25519
+        crypto/internal/fips140/edwards25519/field                   from crypto/ecdh+
+        crypto/internal/fips140/hkdf                                 from crypto/internal/fips140/tls13+
+        crypto/internal/fips140/hmac                                 from crypto/hmac+
+        crypto/internal/fips140/mlkem                                from crypto/tls
+        crypto/internal/fips140/nistec                               from crypto/elliptic+
+        crypto/internal/fips140/nistec/fiat                          from crypto/internal/fips140/nistec
+        crypto/internal/fips140/rsa                                  from crypto/rsa
+        crypto/internal/fips140/sha256                               from crypto/internal/fips140/check+
+        crypto/internal/fips140/sha3                                 from crypto/internal/fips140/hmac+
+        crypto/internal/fips140/sha512                               from crypto/internal/fips140/ecdsa+
+        crypto/internal/fips140/subtle                               from crypto/internal/fips140/aes+
+        crypto/internal/fips140/tls12                                from crypto/tls
+        crypto/internal/fips140/tls13                                from crypto/tls
+        crypto/internal/fips140deps/byteorder                        from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/cpu                              from crypto/internal/fips140/aes+
+        crypto/internal/fips140deps/godebug                          from crypto/internal/fips140+
+        crypto/internal/fips140hash                                  from crypto/ecdsa+
+        crypto/internal/fips140only                                  from crypto/cipher+
         crypto/internal/hpke                                         from crypto/tls
-        crypto/internal/mlkem768                                     from crypto/tls
-        crypto/internal/nistec                                       from crypto/ecdh+
-        crypto/internal/nistec/fiat                                  from crypto/internal/nistec
+        crypto/internal/impl                                         from crypto/internal/fips140/aes+
         crypto/internal/randutil                                     from crypto/dsa+
+        crypto/internal/sysrand                                      from crypto/internal/entropy+
         crypto/md5                                                   from crypto/tls+
         crypto/rand                                                  from crypto/ed25519+
         crypto/rc4                                                   from crypto/tls+
         crypto/rsa                                                   from crypto/tls+
         crypto/sha1                                                  from crypto/tls+
         crypto/sha256                                                from crypto/tls+
+        crypto/sha3                                                  from crypto/internal/fips140hash
         crypto/sha512                                                from crypto/ecdsa+
-        crypto/subtle                                                from crypto/aes+
+        crypto/subtle                                                from crypto/cipher+
         crypto/tls                                                   from github.com/aws/aws-sdk-go-v2/aws/transport/http+
+        crypto/tls/internal/fips140tls                               from crypto/tls
         crypto/x509                                                  from crypto/tls+
    D    crypto/x509/internal/macos                                   from crypto/x509
         crypto/x509/pkix                                             from crypto/x509+
   DW    database/sql/driver                                          from github.com/google/uuid
    W    debug/dwarf                                                  from debug/pe
    W    debug/pe                                                     from github.com/dblohm7/wingoes/pe
-        embed                                                        from crypto/internal/nistec+
+        embed                                                        from github.com/tailscale/web-client-prebuilt+
         encoding                                                     from encoding/gob+
         encoding/asn1                                                from crypto/x509+
         encoding/base32                                              from github.com/fxamacker/cbor/v2+
@@ -562,23 +588,22 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         html                                                         from html/template+
         html/template                                                from github.com/gorilla/csrf
         internal/abi                                                 from crypto/x509/internal/macos+
-        internal/asan                                                from syscall
+        internal/asan                                                from syscall+
         internal/bisect                                              from internal/godebug
         internal/bytealg                                             from bytes+
-        internal/byteorder                                           from crypto/aes+
+        internal/byteorder                                           from crypto/cipher+
         internal/chacha8rand                                         from math/rand/v2+
-        internal/concurrent                                          from unique
         internal/coverage/rtcov                                      from runtime
-        internal/cpu                                                 from crypto/aes+
+        internal/cpu                                                 from crypto/internal/fips140deps/cpu+
         internal/filepathlite                                        from os+
         internal/fmtsort                                             from fmt+
-        internal/goarch                                              from crypto/aes+
+        internal/goarch                                              from crypto/internal/fips140deps/cpu+
         internal/godebug                                             from archive/tar+
         internal/godebugs                                            from internal/godebug+
-        internal/goexperiment                                        from runtime
+        internal/goexperiment                                        from runtime+
         internal/goos                                                from crypto/x509+
         internal/itoa                                                from internal/poll+
-        internal/msan                                                from syscall
+        internal/msan                                                from syscall+
         internal/nettrace                                            from net+
         internal/oserror                                             from io/fs+
         internal/poll                                                from net+
@@ -588,18 +613,21 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         internal/reflectlite                                         from context+
         internal/runtime/atomic                                      from internal/runtime/exithook+
         internal/runtime/exithook                                    from runtime
+        internal/runtime/maps                                        from reflect+
+        internal/runtime/math                                        from internal/runtime/maps+
+        internal/runtime/sys                                         from crypto/subtle+
    L    internal/runtime/syscall                                     from runtime+
         internal/saferio                                             from debug/pe+
         internal/singleflight                                        from net
         internal/stringslite                                         from embed+
+        internal/sync                                                from sync+
         internal/syscall/execenv                                     from os+
-  LD    internal/syscall/unix                                        from crypto/rand+
-   W    internal/syscall/windows                                     from crypto/rand+
+  LD    internal/syscall/unix                                        from crypto/internal/sysrand+
+   W    internal/syscall/windows                                     from crypto/internal/sysrand+
    W    internal/syscall/windows/registry                            from mime+
    W    internal/syscall/windows/sysdll                              from internal/syscall/windows+
         internal/testlog                                             from os
         internal/unsafeheader                                        from internal/reflectlite+
-        internal/weak                                                from unique
         io                                                           from archive/tar+
         io/fs                                                        from archive/tar+
         io/ioutil                                                    from github.com/aws/aws-sdk-go-v2/aws/protocol/query+
@@ -626,7 +654,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         net/netip                                                    from github.com/tailscale/wireguard-go/conn+
         net/textproto                                                from github.com/aws/aws-sdk-go-v2/aws/signer/v4+
         net/url                                                      from crypto/x509+
-        os                                                           from crypto/rand+
+        os                                                           from crypto/internal/sysrand+
         os/exec                                                      from github.com/aws/aws-sdk-go-v2/credentials/processcreds+
         os/signal                                                    from tailscale.com/cmd/tailscaled
         os/user                                                      from archive/tar+
@@ -637,8 +665,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         regexp/syntax                                                from regexp
         runtime                                                      from archive/tar+
         runtime/debug                                                from github.com/aws/aws-sdk-go-v2/internal/sync/singleflight+
-        runtime/internal/math                                        from runtime
-        runtime/internal/sys                                         from runtime
         runtime/pprof                                                from net/http/pprof+
         runtime/trace                                                from net/http/pprof
         slices                                                       from tailscale.com/appc+
@@ -657,3 +683,4 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         unicode/utf8                                                 from bufio+
         unique                                                       from net/netip
         unsafe                                                       from bytes+
+        weak                                                         from unique

cmd/testwrapper/flakytest/flakytest.go

@@ -9,8 +9,12 @@ package flakytest
 import (
 	"fmt"
 	"os"
+	"path"
 	"regexp"
+	"sync"
 	"testing"
+
+	"tailscale.com/util/mak"
 )
 
 // FlakyTestLogMessage is a sentinel value that is printed to stderr when a
@@ -25,6 +29,11 @@ const FlakeAttemptEnv = "TS_TESTWRAPPER_ATTEMPT"
 
 var issueRegexp = regexp.MustCompile(`\Ahttps://github\.com/tailscale/[a-zA-Z0-9_.-]+/issues/\d+\z`)
 
+var (
+	rootFlakesMu sync.Mutex
+	rootFlakes   map[string]bool
+)
+
 // Mark sets the current test as a flaky test, such that if it fails, it will
 // be retried a few times on failure. issue must be a GitHub issue that tracks
 // the status of the flaky test being marked, of the format:
@@ -41,4 +50,24 @@ func Mark(t testing.TB, issue string) {
 		fmt.Fprintf(os.Stderr, "%s: %s\n", FlakyTestLogMessage, issue)
 	}
 	t.Logf("flakytest: issue tracking this flaky test: %s", issue)
+
+	// Record the root test name as flakey.
+	rootFlakesMu.Lock()
+	defer rootFlakesMu.Unlock()
+	mak.Set(&rootFlakes, t.Name(), true)
+}
+
+// Marked reports whether the current test or one of its parents was marked flaky.
+func Marked(t testing.TB) bool {
+	n := t.Name()
+	for {
+		if rootFlakes[n] {
+			return true
+		}
+		n = path.Dir(n)
+		if n == "." || n == "/" {
+			break
+		}
+	}
+	return false
 }

cmd/testwrapper/flakytest/flakytest_test.go

@@ -41,3 +41,49 @@ func TestFlakeRun(t *testing.T) {
 		t.Fatal("First run in testwrapper, failing so that test is retried. This is expected.")
 	}
 }
+
+func TestMarked_Root(t *testing.T) {
+	Mark(t, "https://github.com/tailscale/tailscale/issues/0")
+
+	t.Run("child", func(t *testing.T) {
+		t.Run("grandchild", func(t *testing.T) {
+			if got, want := Marked(t), true; got != want {
+				t.Fatalf("Marked(t) = %t, want %t", got, want)
+			}
+		})
+
+		if got, want := Marked(t), true; got != want {
+			t.Fatalf("Marked(t) = %t, want %t", got, want)
+		}
+	})
+
+	if got, want := Marked(t), true; got != want {
+		t.Fatalf("Marked(t) = %t, want %t", got, want)
+	}
+}
+
+func TestMarked_Subtest(t *testing.T) {
+	t.Run("flaky", func(t *testing.T) {
+		Mark(t, "https://github.com/tailscale/tailscale/issues/0")
+
+		t.Run("child", func(t *testing.T) {
+			t.Run("grandchild", func(t *testing.T) {
+				if got, want := Marked(t), true; got != want {
+					t.Fatalf("Marked(t) = %t, want %t", got, want)
+				}
+			})
+
+			if got, want := Marked(t), true; got != want {
+				t.Fatalf("Marked(t) = %t, want %t", got, want)
+			}
+		})
+
+		if got, want := Marked(t), true; got != want {
+			t.Fatalf("Marked(t) = %t, want %t", got, want)
+		}
+	})
+
+	if got, want := Marked(t), false; got != want {
+		t.Fatalf("Marked(t) = %t, want %t", got, want)
+	}
+}

cmd/testwrapper/testwrapper.go

@@ -10,6 +10,7 @@ package main
 import (
 	"bufio"
 	"bytes"
+	"cmp"
 	"context"
 	"encoding/json"
 	"errors"
@@ -59,11 +60,12 @@ type packageTests struct {
 }
 
 type goTestOutput struct {
-	Time    time.Time
-	Action  string
-	Package string
-	Test    string
-	Output  string
+	Time       time.Time
+	Action     string
+	ImportPath string
+	Package    string
+	Test       string
+	Output     string
 }
 
 var debug = os.Getenv("TS_TESTWRAPPER_DEBUG") != ""
@@ -111,42 +113,43 @@ func runTests(ctx context.Context, attempt int, pt *packageTests, goTestArgs, te
 	for s.Scan() {
 		var goOutput goTestOutput
 		if err := json.Unmarshal(s.Bytes(), &goOutput); err != nil {
-			if errors.Is(err, io.EOF) || errors.Is(err, os.ErrClosed) {
-				break
-			}
-
-			// `go test -json` outputs invalid JSON when a build fails.
-			// In that case, discard the the output and start reading again.
-			// The build error will be printed to stderr.
-			// See: https://github.com/golang/go/issues/35169
-			if _, ok := err.(*json.SyntaxError); ok {
-				fmt.Println(s.Text())
-				continue
-			}
-			panic(err)
+			return fmt.Errorf("failed to parse go test output %q: %w", s.Bytes(), err)
 		}
-		pkg := goOutput.Package
+		pkg := cmp.Or(
+			goOutput.Package,
+			"build:"+goOutput.ImportPath, // can be "./cmd" while Package is "tailscale.com/cmd" so use separate namespace
+		)
 		pkgTests := resultMap[pkg]
 		if pkgTests == nil {
-			pkgTests = make(map[string]*testAttempt)
+			pkgTests = map[string]*testAttempt{
+				"": {}, // Used for start time and build logs.
+			}
 			resultMap[pkg] = pkgTests
 		}
 		if goOutput.Test == "" {
 			switch goOutput.Action {
 			case "start":
-				pkgTests[""] = &testAttempt{start: goOutput.Time}
-			case "fail", "pass", "skip":
+				pkgTests[""].start = goOutput.Time
+			case "build-output":
+				pkgTests[""].logs.WriteString(goOutput.Output)
+			case "build-fail", "fail", "pass", "skip":
 				for _, test := range pkgTests {
 					if test.testName != "" && test.outcome == "" {
 						test.outcome = "fail"
 						ch <- test
 					}
 				}
+				outcome := goOutput.Action
+				if outcome == "build-fail" {
+					outcome = "FAIL"
+				}
+				pkgTests[""].logs.WriteString(goOutput.Output)
 				ch <- &testAttempt{
 					pkg:         goOutput.Package,
-					outcome:     goOutput.Action,
+					outcome:     outcome,
 					start:       pkgTests[""].start,
 					end:         goOutput.Time,
+					logs:        pkgTests[""].logs,
 					pkgFinished: true,
 				}
 			}
@@ -215,6 +218,9 @@ func main() {
 	}
 	toRun := []*nextRun{firstRun}
 	printPkgOutcome := func(pkg, outcome string, attempt int, runtime time.Duration) {
+		if pkg == "" {
+			return // We reach this path on a build error.
+		}
 		if outcome == "skip" {
 			fmt.Printf("?\t%s [skipped/no tests] \n", pkg)
 			return
@@ -270,6 +276,7 @@ func main() {
 						// when a package times out.
 						failed = true
 					}
+					os.Stdout.ReadFrom(&tr.logs)
 					printPkgOutcome(tr.pkg, tr.outcome, thisRun.attempt, tr.end.Sub(tr.start))
 					continue
 				}

cmd/testwrapper/testwrapper_test.go

@@ -11,6 +11,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
+	"strings"
 	"sync"
 	"testing"
 )
@@ -154,24 +155,24 @@ func TestBuildError(t *testing.T) {
 		t.Fatalf("writing package: %s", err)
 	}
 
-	buildErr := []byte("builderror_test.go:3:1: expected declaration, found derp\nFAIL	command-line-arguments [setup failed]")
+	wantErr := "builderror_test.go:3:1: expected declaration, found derp\nFAIL"
 
 	// Confirm `go test` exits with code 1.
 	goOut, err := exec.Command("go", "test", testfile).CombinedOutput()
 	if code, ok := errExitCode(err); !ok || code != 1 {
-		t.Fatalf("go test %s: expected error with exit code 0 but got: %v", testfile, err)
+		t.Fatalf("go test %s: got exit code %d, want 1 (err: %v)", testfile, code, err)
 	}
-	if !bytes.Contains(goOut, buildErr) {
-		t.Fatalf("go test %s: expected build error containing %q but got:\n%s", testfile, buildErr, goOut)
+	if !strings.Contains(string(goOut), wantErr) {
+		t.Fatalf("go test %s: got output %q, want output containing %q", testfile, goOut, wantErr)
 	}
 
 	// Confirm `testwrapper` exits with code 1.
 	twOut, err := cmdTestwrapper(t, testfile).CombinedOutput()
 	if code, ok := errExitCode(err); !ok || code != 1 {
-		t.Fatalf("testwrapper %s: expected error with exit code 0 but got: %v", testfile, err)
+		t.Fatalf("testwrapper %s: got exit code %d, want 1 (err: %v)", testfile, code, err)
 	}
-	if !bytes.Contains(twOut, buildErr) {
-		t.Fatalf("testwrapper %s: expected build error containing %q but got:\n%s", testfile, buildErr, twOut)
+	if !strings.Contains(string(twOut), wantErr) {
+		t.Fatalf("testwrapper %s: got output %q, want output containing %q", testfile, twOut, wantErr)
 	}
 
 	if testing.Verbose() {

cmd/tsconnect/common.go

@@ -176,6 +176,10 @@ func runEsbuild(buildOptions esbuild.BuildOptions) esbuild.BuildResult {
 // wasm_exec.js runtime helper library from the Go toolchain.
 func setupEsbuildWasmExecJS(build esbuild.PluginBuild) {
 	wasmExecSrcPath := filepath.Join(runtime.GOROOT(), "misc", "wasm", "wasm_exec.js")
+	if _, err := os.Stat(wasmExecSrcPath); os.IsNotExist(err) {
+		// Go 1.24+ location:
+		wasmExecSrcPath = filepath.Join(runtime.GOROOT(), "lib", "wasm", "wasm_exec.js")
+	}
 	build.OnResolve(esbuild.OnResolveOptions{
 		Filter: "./wasm_exec$",
 	}, func(args esbuild.OnResolveArgs) (esbuild.OnResolveResult, error) {

control/controlclient/direct.go

@@ -676,7 +676,9 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 	addLBHeader(req, request.OldNodeKey)
 	addLBHeader(req, request.NodeKey)
 
+	start := time.Now()
 	res, err := httpc.Do(req)
+	loginLatencies.Observe(time.Since(start).Seconds())
 	if err != nil {
 		return regen, opt.URL, nil, fmt.Errorf("register request: %w", err)
 	}
@@ -964,7 +966,9 @@ func (c *Direct) sendMapRequest(ctx context.Context, isStreaming bool, nu Netmap
 	}
 	addLBHeader(req, nodeKey)
 
+	start := time.Now()
 	res, err := httpc.Do(req)
+	initialMapRequestLatencies.Observe(time.Since(start).Seconds())
 	if err != nil {
 		vlogf("netmap: Do: %v", err)
 		return err
@@ -1322,6 +1326,7 @@ func (c *Direct) answerPing(pr *tailcfg.PingRequest) {
 		c.logf("invalid PingRequest with no URL")
 		return
 	}
+	start := time.Now()
 	switch pr.Types {
 	case "":
 		answerHeadPing(c.logf, httpc, pr)
@@ -1334,6 +1339,7 @@ func (c *Direct) answerPing(pr *tailcfg.PingRequest) {
 		answerC2NPing(c.logf, c.c2nHandler, httpc, pr)
 		return
 	}
+	answerPingLatencies.Observe(time.Since(start).Seconds())
 	for _, t := range strings.Split(pr.Types, ",") {
 		switch pt := tailcfg.PingType(t); pt {
 		case tailcfg.PingTSMP, tailcfg.PingDisco, tailcfg.PingICMP, tailcfg.PingPeerAPI:
@@ -1638,7 +1644,9 @@ func (c *Direct) ReportHealthChange(w *health.Warnable, us *health.UnhealthyStat
 	// Best effort, no logging:
 	ctx, cancel := context.WithTimeout(c.closedCtx, 5*time.Second)
 	defer cancel()
+	start := time.Now()
 	res, err := np.post(ctx, "/machine/update-health", nodeKey, req)
+	updateHealthLatencies.Observe(time.Since(start).Seconds())
 	if err != nil {
 		return
 	}

control/controlclient/metrics.go

@@ -0,0 +1,39 @@
+package controlclient
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	loginLatencies = promauto.NewHistogram(prometheus.HistogramOpts{
+		Name: "controlclient_login_latency_seconds",
+		Help: "Control login time",
+		// 15 buckets from 10ms to 1m.
+		Buckets: prometheus.ExponentialBucketsRange(0.01, 60, 15)},
+	)
+	dialLatencies = promauto.NewHistogram(prometheus.HistogramOpts{
+		Name: "controlclient_dial_latency_seconds",
+		Help: "Control dial time",
+		// 15 buckets from 10ms to 1m.
+		Buckets: prometheus.ExponentialBucketsRange(0.01, 60, 15)},
+	)
+	initialMapRequestLatencies = promauto.NewHistogram(prometheus.HistogramOpts{
+		Name: "controlclient_initial_map_request_latency_seconds",
+		Help: "Initial map request/response time",
+		// 15 buckets from 10ms to 1m.
+		Buckets: prometheus.ExponentialBucketsRange(0.01, 60, 15)},
+	)
+	updateHealthLatencies = promauto.NewHistogram(prometheus.HistogramOpts{
+		Name: "controlclient_update_health_latency_seconds",
+		Help: "Update health request/response time",
+		// 15 buckets from 10ms to 1m.
+		Buckets: prometheus.ExponentialBucketsRange(0.01, 60, 15)},
+	)
+	answerPingLatencies = promauto.NewHistogram(prometheus.HistogramOpts{
+		Name: "controlclient_answer_ping_latency_seconds",
+		Help: "Answer ping request/response time",
+		// 15 buckets from 10ms to 1m.
+		Buckets: prometheus.ExponentialBucketsRange(0.01, 60, 15)},
+	)
+)

control/controlclient/noise.go

@@ -239,7 +239,9 @@ func (nc *NoiseClient) getConn(ctx context.Context) (*noiseconn.Conn, error) {
 		// which was canceled is our context and retry if our context is still
 		// valid.
 		conn, err, _ := nc.sfDial.Do(struct{}{}, func() (*noiseconn.Conn, error) {
+			start := time.Now()
 			c, err := nc.dial(ctx)
+			dialLatencies.Observe(time.Since(start).Seconds())
 			if err != nil {
 				if ctx.Err() != nil {
 					return nil, contextErr{ctx.Err()}

derp/derp_server.go

@@ -137,6 +137,7 @@ type Server struct {
 	metaCert    []byte // the encoded x509 cert to send after LetsEncrypt cert+intermediate
 	dupPolicy   dupPolicy
 	debug       bool
+	localClient local.Client
 
 	// Counters:
 	packetsSent, bytesSent     expvar.Int
@@ -485,6 +486,16 @@ func (s *Server) SetVerifyClientURLFailOpen(v bool) {
 	s.verifyClientsURLFailOpen = v
 }
 
+// SetTailscaledSocketPath sets the unix socket path to use to talk to
+// tailscaled if client verification is enabled.
+//
+// If unset or set to the empty string, the default path for the operating
+// system is used.
+func (s *Server) SetTailscaledSocketPath(path string) {
+	s.localClient.Socket = path
+	s.localClient.UseSocketOnly = path != ""
+}
+
 // SetTCPWriteTimeout sets the timeout for writing to connected clients.
 // This timeout does not apply to mesh connections.
 // Defaults to 2 seconds.
@@ -1320,8 +1331,6 @@ func (c *sclient) requestMeshUpdate() {
 	}
 }
 
-var localClient local.Client
-
 // isMeshPeer reports whether the client is a trusted mesh peer
 // node in the DERP region.
 func (s *Server) isMeshPeer(info *clientInfo) bool {
@@ -1340,7 +1349,7 @@ func (s *Server) verifyClient(ctx context.Context, clientKey key.NodePublic, inf
 
 	// tailscaled-based verification:
 	if s.verifyClientsLocalTailscaled {
-		_, err := localClient.WhoIsNodeKey(ctx, clientKey)
+		_, err := s.localClient.WhoIsNodeKey(ctx, clientKey)
 		if err == tailscale.ErrPeerNotFound {
 			return fmt.Errorf("peer %v not authorized (not found in local tailscaled)", clientKey)
 		}
@@ -2240,7 +2249,7 @@ func (s *Server) ConsistencyCheck() error {
 func (s *Server) checkVerifyClientsLocalTailscaled() error {
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
-	status, err := localClient.StatusWithoutPeers(ctx)
+	status, err := s.localClient.StatusWithoutPeers(ctx)
 	if err != nil {
 		return fmt.Errorf("localClient.Status: %w", err)
 	}

docs/windows/policy/en-US/tailscale.adml

@@ -109,6 +109,14 @@ If you enable this policy setting, users will not be allowed to disconnect Tails
 If necessary, it can be used along with Unattended Mode to keep Tailscale connected regardless of whether a user is logged in. This can be used to facilitate remote access to a device or ensure connectivity to a Domain Controller before a user logs in.
 
 If you disable or don't configure this policy setting, users will be allowed to disconnect Tailscale at their will.]]></string>
+            <string id="ReconnectAfter">Configure automatic reconnect delay</string>
+            <string id="ReconnectAfter_Help"><![CDATA[This policy setting controls when Tailscale will attempt to reconnect automatically after a user disconnects it. It helps users remain connected most of the time and retain access to corporate resources without preventing them from temporarily disconnecting Tailscale. To configure whether and when Tailscale can be disconnected, see the "Restrict users from disconnecting Tailscale (always-on mode)" policy setting.
+
+If you enable this policy setting, you can specify how long Tailscale will wait before attempting to reconnect after a user disconnects. The value should be specified as a Go duration: for example, 30s, 5m, or 1h30m. If the value is left blank, or if the specified duration is zero, Tailscale will not attempt to reconnect automatically.
+
+If you disable or don't configure this policy setting, Tailscale will only reconnect if a user chooses to or if required by a different policy setting.
+
+Refer to https://pkg.go.dev/time#ParseDuration for information about the supported duration strings.]]></string>
             <string id="ExitNodeAllowLANAccess">Allow Local Network Access when an Exit Node is in use</string>
             <string id="ExitNodeAllowLANAccess_Help"><![CDATA[This policy can be used to require that the Allow Local Network Access setting is configured a certain way.
 
@@ -280,6 +288,12 @@ See https://tailscale.com/kb/1315/mdm-keys#set-your-organization-name for more d
                 <text>The options below allow configuring exceptions where disconnecting Tailscale is permitted.</text>
                 <dropdownList refId="AlwaysOn_OverrideWithReason" noSort="true" defaultItem="0">Disconnects with reason:</dropdownList>
             </presentation>
+            <presentation id="ReconnectAfter">
+                <text>The delay must be a valid Go duration string, such as 30s, 5m, or 1h30m, all without spaces or any other symbols.</text>
+                <textBox refId="ReconnectAfterDelay">
+                    <label>Reconnect after:</label>
+                </textBox>
+            </presentation>
             <presentation id="ExitNodeID">
                 <textBox refId="ExitNodeIDPrompt">
                     <label>Exit Node:</label>

docs/windows/policy/tailscale.admx

@@ -156,6 +156,13 @@
         </enum>
       </elements>
     </policy>
+    <policy name="ReconnectAfter" class="Machine" displayName="$(string.ReconnectAfter)" explainText="$(string.ReconnectAfter_Help)" presentation="$(presentation.ReconnectAfter)" key="Software\Policies\Tailscale">
+      <parentCategory ref="Settings_Category" />
+      <supportedOn ref="SINCE_V1_82" />
+      <elements>
+        <text id="ReconnectAfterDelay" valueName="ReconnectAfter" required="true" />
+      </elements>
+    </policy>
     <policy name="ExitNodeAllowLANAccess" class="Machine" displayName="$(string.ExitNodeAllowLANAccess)" explainText="$(string.ExitNodeAllowLANAccess_Help)" key="Software\Policies\Tailscale" valueName="ExitNodeAllowLANAccess">
       <parentCategory ref="Settings_Category" />
       <supportedOn ref="PARTIAL_FULL_SINCE_V1_56" />

go.mod

@@ -1,6 +1,6 @@
 module tailscale.com
 
-go 1.23.6
+go 1.24.0
 
 require (
 	filippo.io/mkcert v1.4.4
@@ -20,6 +20,7 @@ require (
 	github.com/coder/websocket v1.8.12
 	github.com/coreos/go-iptables v0.7.1-0.20240112124308-65c67c9f46e6
 	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
+	github.com/creachadair/taskgroup v0.13.2
 	github.com/creack/pty v1.1.23
 	github.com/dblohm7/wingoes v0.0.0-20240119213807-a09d6be7affa
 	github.com/digitalocean/go-smbios v0.0.0-20180907143718-390a4f403a8e
@@ -32,7 +33,7 @@ require (
 	github.com/frankban/quicktest v1.14.6
 	github.com/fxamacker/cbor/v2 v2.7.0
 	github.com/gaissmai/bart v0.18.0
-	github.com/go-json-experiment/json v0.0.0-20250103232110-6a9a0fde9288
+	github.com/go-json-experiment/json v0.0.0-20250223041408-d3c622f1b874
 	github.com/go-logr/zapr v1.3.0
 	github.com/go-ole/go-ole v1.3.0
 	github.com/godbus/dbus/v5 v5.1.1-0.20230522191255-76236955d466
@@ -74,10 +75,10 @@ require (
 	github.com/tailscale/certstore v0.1.1-0.20231202035212-d3fa0460f47e
 	github.com/tailscale/depaware v0.0.0-20250112153213-b748de04d81b
 	github.com/tailscale/goexpect v0.0.0-20210902213824-6e8c725cea41
-	github.com/tailscale/golang-x-crypto v0.0.0-20240604161659-3fde5e568aa4
+	github.com/tailscale/golang-x-crypto v0.0.0-20250218230618-9a281fd8faca
 	github.com/tailscale/goupnp v1.0.1-0.20210804011211-c64d0f06ea05
 	github.com/tailscale/hujson v0.0.0-20221223112325-20486734a56a
-	github.com/tailscale/mkctr v0.0.0-20250110151924-54977352e4a6
+	github.com/tailscale/mkctr v0.0.0-20250228050937-c75ea1476830
 	github.com/tailscale/netlink v1.1.1-0.20240822203006-4d49adab4de7
 	github.com/tailscale/peercred v0.0.0-20250107143737-35a0c7bd7edc
 	github.com/tailscale/setec v0.0.0-20250205144240-8898a29c3fbb
@@ -93,7 +94,7 @@ require (
 	go.uber.org/zap v1.27.0
 	go4.org/mem v0.0.0-20240501181205-ae6ca9944745
 	go4.org/netipx v0.0.0-20231129151722-fdeea329fbba
-	golang.org/x/crypto v0.33.0
+	golang.org/x/crypto v0.35.0
 	golang.org/x/exp v0.0.0-20250210185358-939b2ce775ac
 	golang.org/x/mod v0.23.0
 	golang.org/x/net v0.35.0

go.sum

@@ -231,6 +231,8 @@ github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf/go.mod h1:F5haX7
 github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/creachadair/mds v0.17.1 h1:lXQbTGKmb3nE3aK6OEp29L1gCx6B5ynzlQ6c1KOBurc=
 github.com/creachadair/mds v0.17.1/go.mod h1:4b//mUiL8YldH6TImXjmW45myzTLNS1LLjOmrk888eg=
+github.com/creachadair/taskgroup v0.13.2 h1:3KyqakBuFsm3KkXi/9XIb0QcA8tEzLHLgaoidf0MdVc=
+github.com/creachadair/taskgroup v0.13.2/go.mod h1:i3V1Zx7H8RjwljUEeUWYT30Lmb9poewSb2XI1yTwD0g=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/creack/pty v1.1.23 h1:4M6+isWdcStXEf15G/RbrMPOQj1dZ7HPZCGwE4kOeP0=
 github.com/creack/pty v1.1.23/go.mod h1:08sCNb52WyoAwi2QDyzUCTgcvVFhUzewun7wtTfvcwE=
@@ -298,6 +300,8 @@ github.com/firefart/nonamedreturns v1.0.4 h1:abzI1p7mAEPYuR4A+VLKn4eNDOycjYo2phm
 github.com/firefart/nonamedreturns v1.0.4/go.mod h1:TDhe/tjI1BXo48CmYbUduTV7BdIga8MAO/xbKdcVsGI=
 github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8=
 github.com/fogleman/gg v1.3.0/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
+github.com/fortytw2/leaktest v1.3.0 h1:u8491cBMTQ8ft8aeV+adlcytMZylmA5nnwwkRZjI8vw=
+github.com/fortytw2/leaktest v1.3.0/go.mod h1:jDsjWgpAGjm2CA7WthBh/CdZYEPF31XHquHwclZch5g=
 github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
 github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
@@ -327,8 +331,8 @@ github.com/go-git/go-git/v5 v5.13.1/go.mod h1:qryJB4cSBoq3FRoBRf5A77joojuBcmPJ0q
 github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20191125211704-12ad95a8df72/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20200222043503-6f7a984d4dc4/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
-github.com/go-json-experiment/json v0.0.0-20250103232110-6a9a0fde9288 h1:KbX3Z3CgiYlbaavUq3Cj9/MjpO+88S7/AGXzynVDv84=
-github.com/go-json-experiment/json v0.0.0-20250103232110-6a9a0fde9288/go.mod h1:BWmvoE1Xia34f3l/ibJweyhrT+aROb/FQ6d+37F0e2s=
+github.com/go-json-experiment/json v0.0.0-20250223041408-d3c622f1b874 h1:F8d1AJ6M9UQCavhwmO6ZsrYLfG8zVFWfEfMS2MXPkSY=
+github.com/go-json-experiment/json v0.0.0-20250223041408-d3c622f1b874/go.mod h1:TiCD2a1pcmjd7YnhGH0f/zKNcCD06B029pHhzV23c2M=
 github.com/go-kit/kit v0.8.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-kit/kit v0.9.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-kit/log v0.1.0/go.mod h1:zbhenjAZHb184qTLMA9ZjW7ThYL0H2mk7Q6pNt4vbaY=
@@ -900,14 +904,14 @@ github.com/tailscale/go-winio v0.0.0-20231025203758-c4f33415bf55 h1:Gzfnfk2TWrk8
 github.com/tailscale/go-winio v0.0.0-20231025203758-c4f33415bf55/go.mod h1:4k4QO+dQ3R5FofL+SanAUZe+/QfeK0+OIuwDIRu2vSg=
 github.com/tailscale/goexpect v0.0.0-20210902213824-6e8c725cea41 h1:/V2rCMMWcsjYaYO2MeovLw+ClP63OtXgCF2Y1eb8+Ns=
 github.com/tailscale/goexpect v0.0.0-20210902213824-6e8c725cea41/go.mod h1:/roCdA6gg6lQyw/Oz6gIIGu3ggJKYhF+WC/AQReE5XQ=
-github.com/tailscale/golang-x-crypto v0.0.0-20240604161659-3fde5e568aa4 h1:rXZGgEa+k2vJM8xT0PoSKfVXwFGPQ3z3CJfmnHJkZZw=
-github.com/tailscale/golang-x-crypto v0.0.0-20240604161659-3fde5e568aa4/go.mod h1:ikbF+YT089eInTp9f2vmvy4+ZVnW5hzX1q2WknxSprQ=
+github.com/tailscale/golang-x-crypto v0.0.0-20250218230618-9a281fd8faca h1:ecjHwH73Yvqf/oIdQ2vxAX+zc6caQsYdPzsxNW1J3G8=
+github.com/tailscale/golang-x-crypto v0.0.0-20250218230618-9a281fd8faca/go.mod h1:ikbF+YT089eInTp9f2vmvy4+ZVnW5hzX1q2WknxSprQ=
 github.com/tailscale/goupnp v1.0.1-0.20210804011211-c64d0f06ea05 h1:4chzWmimtJPxRs2O36yuGRW3f9SYV+bMTTvMBI0EKio=
 github.com/tailscale/goupnp v1.0.1-0.20210804011211-c64d0f06ea05/go.mod h1:PdCqy9JzfWMJf1H5UJW2ip33/d4YkoKN0r67yKH1mG8=
 github.com/tailscale/hujson v0.0.0-20221223112325-20486734a56a h1:SJy1Pu0eH1C29XwJucQo73FrleVK6t4kYz4NVhp34Yw=
 github.com/tailscale/hujson v0.0.0-20221223112325-20486734a56a/go.mod h1:DFSS3NAGHthKo1gTlmEcSBiZrRJXi28rLNd/1udP1c8=
-github.com/tailscale/mkctr v0.0.0-20250110151924-54977352e4a6 h1:9SuADtKJAGQkIpnpg5znEJ86QaxacN25pHkiEXTDjzg=
-github.com/tailscale/mkctr v0.0.0-20250110151924-54977352e4a6/go.mod h1:qTslktI+Qh9hXo7ZP8xLkl5V8AxUMfxG0xLtkCFLxnw=
+github.com/tailscale/mkctr v0.0.0-20250228050937-c75ea1476830 h1:SwZ72kr1oRzzSPA5PYB4hzPh22UI0nm0dapn3bHaUPs=
+github.com/tailscale/mkctr v0.0.0-20250228050937-c75ea1476830/go.mod h1:qTslktI+Qh9hXo7ZP8xLkl5V8AxUMfxG0xLtkCFLxnw=
 github.com/tailscale/netlink v1.1.1-0.20240822203006-4d49adab4de7 h1:uFsXVBE9Qr4ZoF094vE6iYTLDl0qCiKzYXlL6UeWObU=
 github.com/tailscale/netlink v1.1.1-0.20240822203006-4d49adab4de7/go.mod h1:NzVQi3Mleb+qzq8VmcWpSkcSYxXIg0DkI6XDzpVkhJ0=
 github.com/tailscale/peercred v0.0.0-20250107143737-35a0c7bd7edc h1:24heQPtnFR+yfntqhI3oAu9i27nEojcQ4NuBQOo5ZFA=
@@ -1041,8 +1045,8 @@ golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5y
 golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/crypto v0.1.0/go.mod h1:RecgLatLF4+eUMCP1PoPZQb+cVrJcOPbHkTkbkB9sbw=
 golang.org/x/crypto v0.3.0/go.mod h1:hebNnKkNXi2UzZN1eVRvBB7co0a+JxK6XbPiWVs/3J4=
-golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
-golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/crypto v0.35.0 h1:b15kiHdrGCHrP6LvwaQ3c03kgNhhiMgvlhxHQhmg2Xs=
+golang.org/x/crypto v0.35.0/go.mod h1:dy7dXNW32cAb/6/PRuTNsix8T+vJAqvuIy5Bli/x0YQ=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=

go.toolchain.branch

@@ -1 +1 @@
-tailscale.go1.23
+tailscale.go1.24

go.toolchain.rev

@@ -1 +1 @@
-65c3f5f3fc9d96f56a37a79cad4ebbd7ff985801
+2b494987ff3c1a6a26e10570c490394ff0a77aa4

internal/client/tailscale/tailscale.go

@@ -8,9 +8,16 @@
 package tailscale
 
 import (
+	"errors"
+	"io"
+	"net/http"
+
 	tsclient "tailscale.com/client/tailscale"
 )
 
+// maxSize is the maximum read size (10MB) of responses from the server.
+const maxReadSize = 10 << 20
+
 func init() {
 	tsclient.I_Acknowledge_This_API_Is_Unstable = true
 }
@@ -50,3 +57,27 @@ func NewClient(tailnet string, auth AuthMethod) *Client {
 type Client struct {
 	*tsclient.Client
 }
+
+// HandleErrorResponse is an alias to tailscale.com/client/tailscale.
+func HandleErrorResponse(b []byte, resp *http.Response) error {
+	return tsclient.HandleErrorResponse(b, resp)
+}
+
+// SendRequest add the authentication key to the request and sends it. It
+// receives the response and reads up to 10MB of it.
+func SendRequest(c *Client, req *http.Request) ([]byte, *http.Response, error) {
+	resp, err := c.Do(req)
+	if err != nil {
+		return nil, resp, err
+	}
+	defer resp.Body.Close()
+
+	// Read response. Limit the response to 10MB.
+	// This limit is carried over from client/tailscale/tailscale.go.
+	body := io.LimitReader(resp.Body, maxReadSize+1)
+	b, err := io.ReadAll(body)
+	if len(b) > maxReadSize {
+		err = errors.New("API response too large")
+	}
+	return b, resp, err
+}

internal/client/tailscale/vip_service.go

@@ -0,0 +1,103 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package tailscale
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"tailscale.com/tailcfg"
+	"tailscale.com/util/httpm"
+)
+
+// VIPService is a Tailscale VIPService with Tailscale API JSON representation.
+type VIPService struct {
+	// Name is a VIPService name in form svc:<leftmost-label-of-service-DNS-name>.
+	Name tailcfg.ServiceName `json:"name,omitempty"`
+	// Addrs are the IP addresses of the VIP Service. There are two addresses:
+	// the first is IPv4 and the second is IPv6.
+	// When creating a new VIP Service, the IP addresses are optional: if no
+	// addresses are specified then they will be selected. If an IPv4 address is
+	// specified at index 0, then that address will attempt to be used. An IPv6
+	// address can not be specified upon creation.
+	Addrs []string `json:"addrs,omitempty"`
+	// Comment is an optional text string for display in the admin panel.
+	Comment string `json:"comment,omitempty"`
+	// Ports are the ports of a VIPService that will be configured via Tailscale serve config.
+	// If set, any node wishing to advertise this VIPService must have this port configured via Tailscale serve.
+	Ports []string `json:"ports,omitempty"`
+	// Tags are optional ACL tags that will be applied to the VIPService.
+	Tags []string `json:"tags,omitempty"`
+}
+
+// GetVIPService retrieves a VIPService by its name. It returns 404 if the VIPService is not found.
+func (client *Client) GetVIPService(ctx context.Context, name tailcfg.ServiceName) (*VIPService, error) {
+	path := client.BuildTailnetURL("vip-services", name.String())
+	req, err := http.NewRequestWithContext(ctx, httpm.GET, path, nil)
+	if err != nil {
+		return nil, fmt.Errorf("error creating new HTTP request: %w", err)
+	}
+	b, resp, err := SendRequest(client, req)
+	if err != nil {
+		return nil, fmt.Errorf("error making Tailsale API request: %w", err)
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, HandleErrorResponse(b, resp)
+	}
+	svc := &VIPService{}
+	if err := json.Unmarshal(b, svc); err != nil {
+		return nil, err
+	}
+	return svc, nil
+}
+
+// CreateOrUpdateVIPService creates or updates a VIPService by its name. Caller must ensure that, if the
+// VIPService already exists, the VIPService is fetched first to ensure that any auto-allocated IP addresses are not
+// lost during the update. If the VIPService was created without any IP addresses explicitly set (so that they were
+// auto-allocated by Tailscale) any subsequent request to this function that does not set any IP addresses will error.
+func (client *Client) CreateOrUpdateVIPService(ctx context.Context, svc *VIPService) error {
+	data, err := json.Marshal(svc)
+	if err != nil {
+		return err
+	}
+	path := client.BuildTailnetURL("vip-services", svc.Name.String())
+	req, err := http.NewRequestWithContext(ctx, httpm.PUT, path, bytes.NewBuffer(data))
+	if err != nil {
+		return fmt.Errorf("error creating new HTTP request: %w", err)
+	}
+	b, resp, err := SendRequest(client, req)
+	if err != nil {
+		return fmt.Errorf("error making Tailscale API request: %w", err)
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return HandleErrorResponse(b, resp)
+	}
+	return nil
+}
+
+// DeleteVIPService deletes a VIPService by its name. It returns an error if the VIPService
+// does not exist or if the deletion fails.
+func (client *Client) DeleteVIPService(ctx context.Context, name tailcfg.ServiceName) error {
+	path := client.BuildTailnetURL("vip-services", name.String())
+	req, err := http.NewRequestWithContext(ctx, httpm.DELETE, path, nil)
+	if err != nil {
+		return fmt.Errorf("error creating new HTTP request: %w", err)
+	}
+	b, resp, err := SendRequest(client, req)
+	if err != nil {
+		return fmt.Errorf("error making Tailscale API request: %w", err)
+	}
+	// If status code was not successful, return the error.
+	if resp.StatusCode != http.StatusOK {
+		return HandleErrorResponse(b, resp)
+	}
+	return nil
+}

ipn/ipnlocal/cert.go

@@ -250,15 +250,13 @@ type certStore interface {
 	// for now. If they're expired, it returns errCertExpired.
 	// If they don't exist, it returns ipn.ErrStateNotExist.
 	Read(domain string, now time.Time) (*TLSCertKeyPair, error)
-	// WriteCert writes the cert for domain.
-	WriteCert(domain string, cert []byte) error
-	// WriteKey writes the key for domain.
-	WriteKey(domain string, key []byte) error
 	// ACMEKey returns the value previously stored via WriteACMEKey.
 	// It is a PEM encoded ECDSA key.
 	ACMEKey() ([]byte, error)
 	// WriteACMEKey stores the provided PEM encoded ECDSA key.
 	WriteACMEKey([]byte) error
+	// WriteTLSCertAndKey writes the cert and key for domain.
+	WriteTLSCertAndKey(domain string, cert, key []byte) error
 }
 
 var errCertExpired = errors.New("cert expired")
@@ -344,6 +342,13 @@ func (f certFileStore) WriteKey(domain string, key []byte) error {
 	return atomicfile.WriteFile(keyFile(f.dir, domain), key, 0600)
 }
 
+func (f certFileStore) WriteTLSCertAndKey(domain string, cert, key []byte) error {
+	if err := f.WriteKey(domain, key); err != nil {
+		return err
+	}
+	return f.WriteCert(domain, cert)
+}
+
 // certStateStore implements certStore by storing the cert & key files in an ipn.StateStore.
 type certStateStore struct {
 	ipn.StateStore
@@ -384,6 +389,27 @@ func (s certStateStore) WriteACMEKey(key []byte) error {
 	return ipn.WriteState(s.StateStore, ipn.StateKey(acmePEMName), key)
 }
 
+// TLSCertKeyWriter is an interface implemented by state stores that can write the TLS
+// cert and key in a single atomic operation. Currently this is only implemented
+// by the kubestore.StoreKube.
+type TLSCertKeyWriter interface {
+	WriteTLSCertAndKey(domain string, cert, key []byte) error
+}
+
+// WriteTLSCertAndKey writes the TLS cert and key for domain to the current
+// LocalBackend's StateStore.
+func (s certStateStore) WriteTLSCertAndKey(domain string, cert, key []byte) error {
+	// If we're using a store that supports atomic writes, use that.
+	if aw, ok := s.StateStore.(TLSCertKeyWriter); ok {
+		return aw.WriteTLSCertAndKey(domain, cert, key)
+	}
+	// Otherwise fall back to separate writes for cert and key.
+	if err := s.WriteKey(domain, key); err != nil {
+		return err
+	}
+	return s.WriteCert(domain, cert)
+}
+
 // TLSCertKeyPair is a TLS public and private key, and whether they were obtained
 // from cache or freshly obtained.
 type TLSCertKeyPair struct {
@@ -546,9 +572,6 @@ func (b *LocalBackend) getCertPEM(ctx context.Context, cs certStore, logf logger
 	if err := encodeECDSAKey(&privPEM, certPrivKey); err != nil {
 		return nil, err
 	}
-	if err := cs.WriteKey(domain, privPEM.Bytes()); err != nil {
-		return nil, err
-	}
 
 	csr, err := certRequest(certPrivKey, domain, nil)
 	if err != nil {
@@ -570,7 +593,7 @@ func (b *LocalBackend) getCertPEM(ctx context.Context, cs certStore, logf logger
 			return nil, err
 		}
 	}
-	if err := cs.WriteCert(domain, certPEM.Bytes()); err != nil {
+	if err := cs.WriteTLSCertAndKey(domain, certPEM.Bytes(), privPEM.Bytes()); err != nil {
 		return nil, err
 	}
 	b.domainRenewed(domain)

ipn/ipnlocal/cert_test.go

@@ -86,13 +86,9 @@ func TestCertStoreRoundTrip(t *testing.T) {
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			if err := test.store.WriteCert(testDomain, testCert); err != nil {
-				t.Fatalf("WriteCert: unexpected error: %v", err)
+			if err := test.store.WriteTLSCertAndKey(testDomain, testCert, testKey); err != nil {
+				t.Fatalf("WriteTLSCertAndKey: unexpected error: %v", err)
 			}
-			if err := test.store.WriteKey(testDomain, testKey); err != nil {
-				t.Fatalf("WriteKey: unexpected error: %v", err)
-			}
-
 			kp, err := test.store.Read(testDomain, testNow)
 			if err != nil {
 				t.Fatalf("Read: unexpected error: %v", err)

ipn/ipnlocal/local.go

@@ -442,6 +442,10 @@ type LocalBackend struct {
 	// See tailscale/corp#26146.
 	overrideAlwaysOn bool
 
+	// reconnectTimer is used to schedule a reconnect by setting [ipn.Prefs.WantRunning]
+	// to true after a delay, or nil if no reconnect is scheduled.
+	reconnectTimer tstime.TimerController
+
 	// shutdownCbs are the callbacks to be called when the backend is shutting down.
 	// Each callback is called exactly once in unspecified order and without b.mu held.
 	// Returned errors are logged but otherwise ignored and do not affect the shutdown process.
@@ -614,19 +618,6 @@ func NewLocalBackend(logf logger.Logf, logID logid.PublicID, sys *tsd.System, lo
 		}
 	}
 
-	// initialize Taildrive shares from saved state
-	fs, ok := b.sys.DriveForRemote.GetOK()
-	if ok {
-		currentShares := b.pm.prefs.DriveShares()
-		if currentShares.Len() > 0 {
-			var shares []*drive.Share
-			for _, share := range currentShares.All() {
-				shares = append(shares, share.AsStruct())
-			}
-			fs.SetShares(shares)
-		}
-	}
-
 	for name, newFn := range registeredExtensions {
 		ext, err := newFn(logf, sys)
 		if err != nil {
@@ -1070,6 +1061,8 @@ func (b *LocalBackend) Shutdown() {
 		b.captiveCancel()
 	}
 
+	b.stopReconnectTimerLocked()
+
 	if b.loginFlags&controlclient.LoginEphemeral != 0 {
 		b.mu.Unlock()
 		ctx, cancel := context.WithTimeout(b.ctx, 5*time.Second)
@@ -2341,12 +2334,20 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 		}); err != nil {
 			b.logf("failed to save UpdatePrefs state: %v", err)
 		}
-		b.setAtomicValuesFromPrefsLocked(pv)
-	} else {
-		b.setAtomicValuesFromPrefsLocked(b.pm.CurrentPrefs())
 	}
 
+	// Reset the always-on override whenever Start is called.
+	b.resetAlwaysOnOverrideLocked()
+	// And also apply syspolicy settings to the current profile.
+	// This is important in two cases: when opts.UpdatePrefs is not nil,
+	// and when Always Mode is enabled and we need to set WantRunning to true.
+	if newp := b.pm.CurrentPrefs().AsStruct(); applySysPolicy(newp, b.lastSuggestedExitNode, b.overrideAlwaysOn) {
+		setExitNodeID(newp, b.netMap)
+		b.pm.setPrefsNoPermCheck(newp.View())
+	}
 	prefs := b.pm.CurrentPrefs()
+	b.setAtomicValuesFromPrefsLocked(prefs)
+
 	wantRunning := prefs.WantRunning()
 	if wantRunning {
 		if err := b.initMachineKeyLocked(); err != nil {
@@ -2444,6 +2445,16 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 	b.logf("Backend: logs: be:%v fe:%v", blid, opts.FrontendLogID)
 	b.sendToLocked(ipn.Notify{Prefs: &prefs}, allClients)
 
+	// initialize Taildrive shares from saved state
+	if fs, ok := b.sys.DriveForRemote.GetOK(); ok {
+		currentShares := b.pm.CurrentPrefs().DriveShares()
+		var shares []*drive.Share
+		for _, share := range currentShares.All() {
+			shares = append(shares, share.AsStruct())
+		}
+		fs.SetShares(shares)
+	}
+
 	if !loggedOut && (b.hasNodeKeyLocked() || confWantRunning) {
 		// If we know that we're either logged in or meant to be
 		// running, tell the controlclient that it should also assume
@@ -4289,15 +4300,75 @@ func (b *LocalBackend) EditPrefsAs(mp *ipn.MaskedPrefs, actor ipnauth.Actor) (ip
 		// mode on them until the policy changes, they switch to a different profile, etc.
 		b.overrideAlwaysOn = true
 
-		// TODO(nickkhyl): check the ReconnectAfter policy here. If configured,
-		// start a timer to automatically reconnect after the specified duration.
+		if reconnectAfter, _ := syspolicy.GetDuration(syspolicy.ReconnectAfter, 0); reconnectAfter > 0 {
+			b.startReconnectTimerLocked(reconnectAfter)
+		}
 	}
 
 	return b.editPrefsLockedOnEntry(mp, unlock)
 }
 
+// startReconnectTimerLocked sets a timer to automatically set WantRunning to true
+// after the specified duration.
+func (b *LocalBackend) startReconnectTimerLocked(d time.Duration) {
+	if b.reconnectTimer != nil {
+		// Stop may return false if the timer has already fired,
+		// and the function has been called in its own goroutine,
+		// but lost the race to acquire b.mu. In this case, it'll
+		// end up as a no-op due to a reconnectTimer mismatch
+		// once it manages to acquire the lock. This is fine, and we
+		// don't need to check the return value.
+		b.reconnectTimer.Stop()
+	}
+	profileID := b.pm.CurrentProfile().ID()
+	var reconnectTimer tstime.TimerController
+	reconnectTimer = b.clock.AfterFunc(d, func() {
+		unlock := b.lockAndGetUnlock()
+		defer unlock()
+
+		if b.reconnectTimer != reconnectTimer {
+			// We're either not the most recent timer, or we lost the race when
+			// the timer was stopped. No need to reconnect.
+			return
+		}
+		b.reconnectTimer = nil
+
+		cp := b.pm.CurrentProfile()
+		if cp.ID() != profileID {
+			// The timer fired before the profile changed but we lost the race
+			// and acquired the lock shortly after.
+			// No need to reconnect.
+			return
+		}
+
+		mp := &ipn.MaskedPrefs{WantRunningSet: true, Prefs: ipn.Prefs{WantRunning: true}}
+		if _, err := b.editPrefsLockedOnEntry(mp, unlock); err != nil {
+			b.logf("failed to automatically reconnect as %q after %v: %v", cp.Name(), d, err)
+		} else {
+			b.logf("automatically reconnected as %q after %v", cp.Name(), d)
+		}
+	})
+	b.reconnectTimer = reconnectTimer
+	b.logf("reconnect for %q has been scheduled and will be performed in %v", b.pm.CurrentProfile().Name(), d)
+}
+
 func (b *LocalBackend) resetAlwaysOnOverrideLocked() {
 	b.overrideAlwaysOn = false
+	b.stopReconnectTimerLocked()
+}
+
+func (b *LocalBackend) stopReconnectTimerLocked() {
+	if b.reconnectTimer != nil {
+		// Stop may return false if the timer has already fired,
+		// and the function has been called in its own goroutine,
+		// but lost the race to acquire b.mu.
+		// In this case, it'll end up as a no-op due to a reconnectTimer
+		// mismatch (see [LocalBackend.startReconnectTimerLocked])
+		// once it manages to acquire the lock. This is fine, and we
+		// don't need to check the return value.
+		b.reconnectTimer.Stop()
+		b.reconnectTimer = nil
+	}
 }
 
 // Warning: b.mu must be held on entry, but it unlocks it on the way out.
@@ -4391,7 +4462,7 @@ func (b *LocalBackend) setPrefsLockedOnEntry(newp *ipn.Prefs, unlock unlockOnce)
 	if oldp.Valid() {
 		newp.Persist = oldp.Persist().AsStruct() // caller isn't allowed to override this
 	}
-	// applySysPolicyToPrefsLocked returns whether it updated newp,
+	// applySysPolicy returns whether it updated newp,
 	// but everything in this function treats b.prefs as completely new
 	// anyway, so its return value can be ignored here.
 	applySysPolicy(newp, b.lastSuggestedExitNode, b.overrideAlwaysOn)
@@ -6635,7 +6706,7 @@ func (b *LocalBackend) FileTargets() ([]*apitype.FileTarget, error) {
 }
 
 func (b *LocalBackend) taildropTargetStatus(p tailcfg.NodeView) ipnstate.TaildropTargetStatus {
-	if b.netMap == nil || b.state != ipn.Running {
+	if b.state != ipn.Running {
 		return ipnstate.TaildropTargetIpnStateNotRunning
 	}
 	if b.netMap == nil {
@@ -8148,15 +8219,13 @@ func (b *LocalBackend) vipServiceHash(services []*tailcfg.VIPService) string {
 func (b *LocalBackend) vipServicesFromPrefsLocked(prefs ipn.PrefsView) []*tailcfg.VIPService {
 	// keyed by service name
 	var services map[tailcfg.ServiceName]*tailcfg.VIPService
-	if !b.serveConfig.Valid() {
-		return nil
-	}
-
-	for svc, config := range b.serveConfig.Services().All() {
-		mak.Set(&services, svc, &tailcfg.VIPService{
-			Name:  svc,
-			Ports: config.ServicePortRange(),
-		})
+	if b.serveConfig.Valid() {
+		for svc, config := range b.serveConfig.Services().All() {
+			mak.Set(&services, svc, &tailcfg.VIPService{
+				Name:  svc,
+				Ports: config.ServicePortRange(),
+			})
+		}
 	}
 
 	for _, s := range prefs.AdvertiseServices().All() {

ipn/ipnstate/ipnstate.go

@@ -216,6 +216,11 @@ type PeerStatusLite struct {
 }
 
 // PeerStatus describes a peer node and its current state.
+// WARNING: The fields in PeerStatus are merged by the AddPeer method in the StatusBuilder.
+// When adding a new field to PeerStatus, you must update AddPeer to handle merging
+// the new field. The AddPeer function is responsible for combining multiple updates
+// to the same peer, and any new field that is not merged properly may lead to
+// inconsistencies or lost data in the peer status.
 type PeerStatus struct {
 	ID        tailcfg.StableNodeID
 	PublicKey key.NodePublic
@@ -533,6 +538,9 @@ func (sb *StatusBuilder) AddPeer(peer key.NodePublic, st *PeerStatus) {
 	if v := st.Capabilities; v != nil {
 		e.Capabilities = v
 	}
+	if v := st.TaildropTarget; v != TaildropTargetUnknown {
+		e.TaildropTarget = v
+	}
 	e.Location = st.Location
 }
 

ipn/store/awsstore/store_aws.go

@@ -10,7 +10,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net/url"
 	"regexp"
+	"strings"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/aws/aws-sdk-go-v2/aws/arn"
@@ -28,6 +30,14 @@ const (
 
 var parameterNameRx = regexp.MustCompile(parameterNameRxStr)
 
+// Option defines a functional option type for configuring awsStore.
+type Option func(*storeOptions)
+
+// storeOptions holds optional settings for creating a new awsStore.
+type storeOptions struct {
+	kmsKey string
+}
+
 // awsSSMClient is an interface allowing us to mock the couple of
 // API calls we are leveraging with the AWSStore provider
 type awsSSMClient interface {
@@ -46,6 +56,10 @@ type awsStore struct {
 	ssmClient awsSSMClient
 	ssmARN    arn.ARN
 
+	// kmsKey is optional. If empty, the parameter is stored in plaintext.
+	// If non-empty, the parameter is encrypted with this KMS key.
+	kmsKey string
+
 	memory mem.Store
 }
 
@@ -57,30 +71,80 @@ type awsStore struct {
 // Tailscaled to only only store new state in-memory and
 // restarting Tailscaled can fail until you delete your state
 // from the AWS Parameter Store.
-func New(_ logger.Logf, ssmARN string) (ipn.StateStore, error) {
-	return newStore(ssmARN, nil)
+//
+// If you want to specify an optional KMS key,
+// pass one or more Option objects, e.g. awsstore.WithKeyID("alias/my-key").
+func New(_ logger.Logf, ssmARN string, opts ...Option) (ipn.StateStore, error) {
+	// Apply all options to an empty storeOptions
+	var so storeOptions
+	for _, opt := range opts {
+		opt(&so)
+	}
+
+	return newStore(ssmARN, so, nil)
+}
+
+// WithKeyID sets the KMS key to be used for encryption. It can be
+// a KeyID, an alias ("alias/my-key"), or a full ARN.
+//
+// If kmsKey is empty, the Option is a no-op.
+func WithKeyID(kmsKey string) Option {
+	return func(o *storeOptions) {
+		o.kmsKey = kmsKey
+	}
+}
+
+// ParseARNAndOpts parses an ARN and optional URL-encoded parameters
+// from arg.
+func ParseARNAndOpts(arg string) (ssmARN string, opts []Option, err error) {
+	ssmARN = arg
+
+	// Support optional ?url-encoded-parameters.
+	if s, q, ok := strings.Cut(arg, "?"); ok {
+		ssmARN = s
+		q, err := url.ParseQuery(q)
+		if err != nil {
+			return "", nil, err
+		}
+
+		for k := range q {
+			switch k {
+			default:
+				return "", nil, fmt.Errorf("unknown arn option parameter %q", k)
+			case "kmsKey":
+				// We allow an ARN, a key ID, or an alias name for kmsKeyID.
+				// If it doesn't look like an ARN and doesn't have a '/',
+				// prepend "alias/" for KMS alias references.
+				kmsKey := q.Get(k)
+				if kmsKey != "" &&
+					!strings.Contains(kmsKey, "/") &&
+					!strings.HasPrefix(kmsKey, "arn:") {
+					kmsKey = "alias/" + kmsKey
+				}
+				if kmsKey != "" {
+					opts = append(opts, WithKeyID(kmsKey))
+				}
+			}
+		}
+	}
+	return ssmARN, opts, nil
 }
 
 // newStore is NewStore, but for tests. If client is non-nil, it's
 // used instead of making one.
-func newStore(ssmARN string, client awsSSMClient) (ipn.StateStore, error) {
+func newStore(ssmARN string, so storeOptions, client awsSSMClient) (ipn.StateStore, error) {
 	s := &awsStore{
 		ssmClient: client,
+		kmsKey:    so.kmsKey,
 	}
 
 	var err error
-
-	// Parse the ARN
 	if s.ssmARN, err = arn.Parse(ssmARN); err != nil {
 		return nil, fmt.Errorf("unable to parse the ARN correctly: %v", err)
 	}
-
-	// Validate the ARN corresponds to the SSM service
 	if s.ssmARN.Service != "ssm" {
 		return nil, fmt.Errorf("invalid service %q, expected 'ssm'", s.ssmARN.Service)
 	}
-
-	// Validate the ARN corresponds to a parameter store resource
 	if !parameterNameRx.MatchString(s.ssmARN.Resource) {
 		return nil, fmt.Errorf("invalid resource %q, expected to match %v", s.ssmARN.Resource, parameterNameRxStr)
 	}
@@ -96,12 +160,11 @@ func newStore(ssmARN string, client awsSSMClient) (ipn.StateStore, error) {
 		s.ssmClient = ssm.NewFromConfig(cfg)
 	}
 
-	// Hydrate cache with the potentially current state
+	// Preload existing state, if any
 	if err := s.LoadState(); err != nil {
 		return nil, err
 	}
 	return s, nil
-
 }
 
 // LoadState attempts to read the state from AWS SSM parameter store key.
@@ -172,15 +235,21 @@ func (s *awsStore) persistState() error {
 	// which is free. However, if it exceeds 4kb it switches the parameter to advanced tiering
 	// doubling the capacity to 8kb per the following docs:
 	// https://aws.amazon.com/about-aws/whats-new/2019/08/aws-systems-manager-parameter-store-announces-intelligent-tiering-to-enable-automatic-parameter-tier-selection/
-	_, err = s.ssmClient.PutParameter(
-		context.TODO(),
-		&ssm.PutParameterInput{
-			Name:      aws.String(s.ParameterName()),
-			Value:     aws.String(string(bs)),
-			Overwrite: aws.Bool(true),
-			Tier:      ssmTypes.ParameterTierIntelligentTiering,
-			Type:      ssmTypes.ParameterTypeSecureString,
-		},
-	)
+	in := &ssm.PutParameterInput{
+		Name:      aws.String(s.ParameterName()),
+		Value:     aws.String(string(bs)),
+		Overwrite: aws.Bool(true),
+		Tier:      ssmTypes.ParameterTierIntelligentTiering,
+		Type:      ssmTypes.ParameterTypeSecureString,
+	}
+
+	// If kmsKey is specified, encrypt with that key
+	// NOTE: this input allows any alias, keyID or ARN
+	// If this isn't specified, AWS will use the default KMS key
+	if s.kmsKey != "" {
+		in.KeyId = aws.String(s.kmsKey)
+	}
+
+	_, err = s.ssmClient.PutParameter(context.TODO(), in)
 	return err
 }

ipn/store/awsstore/store_aws_stub.go

@@ -1,18 +0,0 @@
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-
-//go:build !linux || ts_omit_aws
-
-package awsstore
-
-import (
-	"fmt"
-	"runtime"
-
-	"tailscale.com/ipn"
-	"tailscale.com/types/logger"
-)
-
-func New(logger.Logf, string) (ipn.StateStore, error) {
-	return nil, fmt.Errorf("AWS store is not supported on %v", runtime.GOOS)
-}

ipn/store/awsstore/store_aws_test.go

@@ -1,7 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build linux
+//go:build linux && !ts_omit_aws
 
 package awsstore
 
@@ -65,7 +65,11 @@ func TestNewAWSStore(t *testing.T) {
 		Resource:  "parameter/foo",
 	}
 
-	s, err := newStore(storeParameterARN.String(), mc)
+	opts := storeOptions{
+		kmsKey: "arn:aws:kms:eu-west-1:123456789:key/MyCustomKey",
+	}
+
+	s, err := newStore(storeParameterARN.String(), opts, mc)
 	if err != nil {
 		t.Fatalf("creating aws store failed: %v", err)
 	}
@@ -73,7 +77,7 @@ func TestNewAWSStore(t *testing.T) {
 
 	// Build a brand new file store and check that both IDs written
 	// above are still there.
-	s2, err := newStore(storeParameterARN.String(), mc)
+	s2, err := newStore(storeParameterARN.String(), opts, mc)
 	if err != nil {
 		t.Fatalf("creating second aws store failed: %v", err)
 	}
@@ -162,3 +166,54 @@ func testStoreSemantics(t *testing.T, store ipn.StateStore) {
 		}
 	}
 }
+
+func TestParseARNAndOpts(t *testing.T) {
+	tests := []struct {
+		name    string
+		arg     string
+		wantARN string
+		wantKey string
+	}{
+		{
+			name:    "no-key",
+			arg:     "arn:aws:ssm:us-east-1:123456789012:parameter/myTailscaleParam",
+			wantARN: "arn:aws:ssm:us-east-1:123456789012:parameter/myTailscaleParam",
+		},
+		{
+			name:    "custom-key",
+			arg:     "arn:aws:ssm:us-east-1:123456789012:parameter/myTailscaleParam?kmsKey=alias/MyCustomKey",
+			wantARN: "arn:aws:ssm:us-east-1:123456789012:parameter/myTailscaleParam",
+			wantKey: "alias/MyCustomKey",
+		},
+		{
+			name:    "bare-name",
+			arg:     "arn:aws:ssm:us-east-1:123456789012:parameter/myTailscaleParam?kmsKey=Bare",
+			wantARN: "arn:aws:ssm:us-east-1:123456789012:parameter/myTailscaleParam",
+			wantKey: "alias/Bare",
+		},
+		{
+			name:    "arn-arg",
+			arg:     "arn:aws:ssm:us-east-1:123456789012:parameter/myTailscaleParam?kmsKey=arn:foo",
+			wantARN: "arn:aws:ssm:us-east-1:123456789012:parameter/myTailscaleParam",
+			wantKey: "arn:foo",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			arn, opts, err := ParseARNAndOpts(tt.arg)
+			if err != nil {
+				t.Fatalf("New: %v", err)
+			}
+			if arn != tt.wantARN {
+				t.Errorf("ARN = %q; want %q", arn, tt.wantARN)
+			}
+			var got storeOptions
+			for _, opt := range opts {
+				opt(&got)
+			}
+			if got.kmsKey != tt.wantKey {
+				t.Errorf("kmsKey = %q; want %q", got.kmsKey, tt.wantKey)
+			}
+		})
+	}
+}

ipn/store/kubestore/store_kube.go

@@ -18,6 +18,7 @@ import (
 	"tailscale.com/kube/kubeapi"
 	"tailscale.com/kube/kubeclient"
 	"tailscale.com/types/logger"
+	"tailscale.com/util/mak"
 )
 
 const (
@@ -83,10 +84,26 @@ func (s *Store) ReadState(id ipn.StateKey) ([]byte, error) {
 
 // WriteState implements the StateStore interface.
 func (s *Store) WriteState(id ipn.StateKey, bs []byte) (err error) {
+	return s.updateStateSecret(map[string][]byte{string(id): bs})
+}
+
+// WriteTLSCertAndKey writes a TLS cert and key to domain.crt, domain.key fields of a Tailscale Kubernetes node's state
+// Secret.
+func (s *Store) WriteTLSCertAndKey(domain string, cert, key []byte) error {
+	return s.updateStateSecret(map[string][]byte{domain + ".crt": cert, domain + ".key": key})
+}
+
+func (s *Store) updateStateSecret(data map[string][]byte) (err error) {
 	ctx, cancel := context.WithTimeout(context.Background(), timeout)
 	defer func() {
 		if err == nil {
-			s.memory.WriteState(ipn.StateKey(sanitizeKey(id)), bs)
+			for id, bs := range data {
+				// The in-memory store does not distinguish between values read from state Secret on
+				// init and values written to afterwards. Values read from the state
+				// Secret will always be sanitized, so we also need to sanitize values written to store
+				// later, so that the Read logic can just lookup keys in sanitized form.
+				s.memory.WriteState(ipn.StateKey(sanitizeKey(id)), bs)
+			}
 		}
 		if err != nil {
 			if err := s.client.Event(ctx, eventTypeWarning, reasonTailscaleStateUpdateFailed, err.Error()); err != nil {
@@ -99,9 +116,9 @@ func (s *Store) WriteState(id ipn.StateKey, bs []byte) (err error) {
 		}
 		cancel()
 	}()
-
 	secret, err := s.client.GetSecret(ctx, s.secretName)
 	if err != nil {
+		// If the Secret does not exist, create it with the required data.
 		if kubeclient.IsNotFoundErr(err) {
 			return s.client.CreateSecret(ctx, &kubeapi.Secret{
 				TypeMeta: kubeapi.TypeMeta{
@@ -111,40 +128,53 @@ func (s *Store) WriteState(id ipn.StateKey, bs []byte) (err error) {
 				ObjectMeta: kubeapi.ObjectMeta{
 					Name: s.secretName,
 				},
-				Data: map[string][]byte{
-					sanitizeKey(id): bs,
-				},
+				Data: func(m map[string][]byte) map[string][]byte {
+					d := make(map[string][]byte, len(m))
+					for key, val := range m {
+						d[sanitizeKey(key)] = val
+					}
+					return d
+				}(data),
 			})
 		}
 		return err
 	}
 	if s.canPatch {
-		if len(secret.Data) == 0 { // if user has pre-created a blank Secret
-			m := []kubeclient.JSONPatch{
+		var m []kubeclient.JSONPatch
+		// If the user has pre-created a Secret with no data, we need to ensure the top level /data field.
+		if len(secret.Data) == 0 {
+			m = []kubeclient.JSONPatch{
 				{
-					Op:    "add",
-					Path:  "/data",
-					Value: map[string][]byte{sanitizeKey(id): bs},
+					Op:   "add",
+					Path: "/data",
+					Value: func(m map[string][]byte) map[string][]byte {
+						d := make(map[string][]byte, len(m))
+						for key, val := range m {
+							d[sanitizeKey(key)] = val
+						}
+						return d
+					}(data),
 				},
 			}
-			if err := s.client.JSONPatchResource(ctx, s.secretName, kubeclient.TypeSecrets, m); err != nil {
-				return fmt.Errorf("error patching Secret %s with a /data field: %v", s.secretName, err)
+			// If the Secret has data, patch it with the new data.
+		} else {
+			for key, val := range data {
+				m = append(m, kubeclient.JSONPatch{
+					Op:    "add",
+					Path:  "/data/" + sanitizeKey(key),
+					Value: val,
+				})
 			}
-			return nil
-		}
-		m := []kubeclient.JSONPatch{
-			{
-				Op:    "add",
-				Path:  "/data/" + sanitizeKey(id),
-				Value: bs,
-			},
 		}
 		if err := s.client.JSONPatchResource(ctx, s.secretName, kubeclient.TypeSecrets, m); err != nil {
-			return fmt.Errorf("error patching Secret %s with /data/%s field: %v", s.secretName, sanitizeKey(id), err)
+			return fmt.Errorf("error patching Secret %s: %w", s.secretName, err)
 		}
 		return nil
 	}
-	secret.Data[sanitizeKey(id)] = bs
+	// No patch permissions, use UPDATE instead.
+	for key, val := range data {
+		mak.Set(&secret.Data, sanitizeKey(key), val)
+	}
 	if err := s.client.UpdateSecret(ctx, secret); err != nil {
 		return err
 	}
@@ -172,9 +202,10 @@ func (s *Store) loadState() (err error) {
 	return nil
 }
 
-func sanitizeKey(k ipn.StateKey) string {
-	// The only valid characters in a Kubernetes secret key are alphanumeric, -,
-	// _, and .
+// sanitizeKey converts any value that can be converted to a string into a valid Kubernetes Secret key.
+// Valid characters are alphanumeric, -, _, and .
+// https://kubernetes.io/docs/concepts/configuration/secret/#restriction-names-data.
+func sanitizeKey[T ~string](k T) string {
 	return strings.Map(func(r rune) rune {
 		if r >= 'a' && r <= 'z' || r >= 'A' && r <= 'Z' || r >= '0' && r <= '9' || r == '-' || r == '_' || r == '.' {
 			return r

ipn/store/kubestore/store_kube_test.go

@@ -0,0 +1,183 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package kubestore
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"tailscale.com/ipn"
+	"tailscale.com/ipn/store/mem"
+	"tailscale.com/kube/kubeapi"
+	"tailscale.com/kube/kubeclient"
+)
+
+func TestUpdateStateSecret(t *testing.T) {
+	tests := []struct {
+		name       string
+		initial    map[string][]byte
+		updates    map[string][]byte
+		wantData   map[string][]byte
+		allowPatch bool
+	}{
+		{
+			name: "basic_update",
+			initial: map[string][]byte{
+				"existing": []byte("old"),
+			},
+			updates: map[string][]byte{
+				"foo": []byte("bar"),
+			},
+			wantData: map[string][]byte{
+				"existing": []byte("old"),
+				"foo":      []byte("bar"),
+			},
+			allowPatch: true,
+		},
+		{
+			name: "update_existing",
+			initial: map[string][]byte{
+				"foo": []byte("old"),
+			},
+			updates: map[string][]byte{
+				"foo": []byte("new"),
+			},
+			wantData: map[string][]byte{
+				"foo": []byte("new"),
+			},
+			allowPatch: true,
+		},
+		{
+			name: "multiple_updates",
+			initial: map[string][]byte{
+				"keep": []byte("keep"),
+			},
+			updates: map[string][]byte{
+				"foo": []byte("bar"),
+				"baz": []byte("qux"),
+			},
+			wantData: map[string][]byte{
+				"keep": []byte("keep"),
+				"foo":  []byte("bar"),
+				"baz":  []byte("qux"),
+			},
+			allowPatch: true,
+		},
+		{
+			name: "create_new_secret",
+			updates: map[string][]byte{
+				"foo": []byte("bar"),
+			},
+			wantData: map[string][]byte{
+				"foo": []byte("bar"),
+			},
+			allowPatch: true,
+		},
+		{
+			name: "patch_denied",
+			initial: map[string][]byte{
+				"foo": []byte("old"),
+			},
+			updates: map[string][]byte{
+				"foo": []byte("new"),
+			},
+			wantData: map[string][]byte{
+				"foo": []byte("new"),
+			},
+			allowPatch: false,
+		},
+		{
+			name: "sanitize_keys",
+			initial: map[string][]byte{
+				"clean-key": []byte("old"),
+			},
+			updates: map[string][]byte{
+				"dirty@key": []byte("new"),
+				"also/bad":  []byte("value"),
+				"good.key":  []byte("keep"),
+			},
+			wantData: map[string][]byte{
+				"clean-key": []byte("old"),
+				"dirty_key": []byte("new"),
+				"also_bad":  []byte("value"),
+				"good.key":  []byte("keep"),
+			},
+			allowPatch: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			secret := tt.initial // track current state
+			client := &kubeclient.FakeClient{
+				GetSecretImpl: func(ctx context.Context, name string) (*kubeapi.Secret, error) {
+					if secret == nil {
+						return nil, &kubeapi.Status{Code: 404}
+					}
+					return &kubeapi.Secret{Data: secret}, nil
+				},
+				CheckSecretPermissionsImpl: func(ctx context.Context, name string) (bool, bool, error) {
+					return tt.allowPatch, true, nil
+				},
+				CreateSecretImpl: func(ctx context.Context, s *kubeapi.Secret) error {
+					secret = s.Data
+					return nil
+				},
+				UpdateSecretImpl: func(ctx context.Context, s *kubeapi.Secret) error {
+					secret = s.Data
+					return nil
+				},
+				JSONPatchResourceImpl: func(ctx context.Context, name, resourceType string, patches []kubeclient.JSONPatch) error {
+					if !tt.allowPatch {
+						return &kubeapi.Status{Reason: "Forbidden"}
+					}
+					if secret == nil {
+						secret = make(map[string][]byte)
+					}
+					for _, p := range patches {
+						if p.Op == "add" && p.Path == "/data" {
+							secret = p.Value.(map[string][]byte)
+						} else if p.Op == "add" && strings.HasPrefix(p.Path, "/data/") {
+							key := strings.TrimPrefix(p.Path, "/data/")
+							secret[key] = p.Value.([]byte)
+						}
+					}
+					return nil
+				},
+			}
+
+			s := &Store{
+				client:     client,
+				canPatch:   tt.allowPatch,
+				secretName: "test-secret",
+				memory:     mem.Store{},
+			}
+
+			err := s.updateStateSecret(tt.updates)
+			if err != nil {
+				t.Errorf("updateStateSecret() error = %v", err)
+				return
+			}
+
+			// Verify secret data
+			if diff := cmp.Diff(secret, tt.wantData); diff != "" {
+				t.Errorf("secret data mismatch (-got +want):\n%s", diff)
+			}
+
+			// Verify memory store was updated
+			for k, v := range tt.updates {
+				got, err := s.memory.ReadState(ipn.StateKey(sanitizeKey(k)))
+				if err != nil {
+					t.Errorf("reading from memory store: %v", err)
+					continue
+				}
+				if !cmp.Equal(got, v) {
+					t.Errorf("memory store key %q = %v, want %v", k, got, v)
+				}
+			}
+		})
+	}
+}

ipn/store/store_aws.go

@@ -6,7 +6,9 @@
 package store
 
 import (
+	"tailscale.com/ipn"
 	"tailscale.com/ipn/store/awsstore"
+	"tailscale.com/types/logger"
 )
 
 func init() {
@@ -14,5 +16,11 @@ func init() {
 }
 
 func registerAWSStore() {
-	Register("arn:", awsstore.New)
+	Register("arn:", func(logf logger.Logf, arg string) (ipn.StateStore, error) {
+		ssmARN, opts, err := awsstore.ParseARNAndOpts(arg)
+		if err != nil {
+			return nil, err
+		}
+		return awsstore.New(logf, ssmARN, opts...)
+	})
 }

kube/kubeclient/fake_client.go

@@ -15,6 +15,9 @@ var _ Client = &FakeClient{}
 type FakeClient struct {
 	GetSecretImpl              func(context.Context, string) (*kubeapi.Secret, error)
 	CheckSecretPermissionsImpl func(ctx context.Context, name string) (bool, bool, error)
+	CreateSecretImpl           func(context.Context, *kubeapi.Secret) error
+	UpdateSecretImpl           func(context.Context, *kubeapi.Secret) error
+	JSONPatchResourceImpl      func(context.Context, string, string, []JSONPatch) error
 }
 
 func (fc *FakeClient) CheckSecretPermissions(ctx context.Context, name string) (bool, bool, error) {
@@ -33,8 +36,12 @@ func (fc *FakeClient) Event(context.Context, string, string, string) error {
 	return nil
 }
 
-func (fc *FakeClient) JSONPatchResource(context.Context, string, string, []JSONPatch) error {
-	return nil
+func (fc *FakeClient) JSONPatchResource(ctx context.Context, resource, name string, patches []JSONPatch) error {
+	return fc.JSONPatchResourceImpl(ctx, resource, name, patches)
+}
+func (fc *FakeClient) UpdateSecret(ctx context.Context, secret *kubeapi.Secret) error {
+	return fc.UpdateSecretImpl(ctx, secret)
+}
+func (fc *FakeClient) CreateSecret(ctx context.Context, secret *kubeapi.Secret) error {
+	return fc.CreateSecretImpl(ctx, secret)
 }
-func (fc *FakeClient) UpdateSecret(context.Context, *kubeapi.Secret) error { return nil }
-func (fc *FakeClient) CreateSecret(context.Context, *kubeapi.Secret) error { return nil }

licenses/README.md

@@ -0,0 +1,35 @@
+# Licenses
+
+This directory contains a list of dependencies, and their licenses, that are included in the Tailscale clients.
+These lists are generated using the [go-licenses] tool to analyze all Go packages in the Tailscale binaries,
+as well as a set of custom output templates that includes any additional non-Go dependencies.
+For example, the clients for macOS and iOS include some additional Swift libraries.
+
+These lists are updated roughly every week, so it is possible to see the dependencies in a given release by looking at the release tag.
+For example, the dependences for the 1.80.0 release of the macOS client can be seen at
+<https://github.com/tailscale/tailscale/blob/v1.80.0/licenses/apple.md>.
+
+[go-licenses]: https://github.com/google/go-licenses
+
+## Other formats
+
+The go-licenses tool can output other formats like CSV, but that wouldn't include the non-Go dependencies.
+We can generate a CSV file if that's really needed by running a regex over the markdown files:
+
+```sh
+cat apple.md | grep "^ -" | sed -E "s/- \[(.*)\]\(.*?\) \(\[(.*)\]\((.*)\)\)/\1,\2,\3/"
+```
+
+## Reviewer instructions
+
+The majority of changes in this directory are from updating dependency versions.
+In that case, only the URL for the license file will change to reflect the new version.
+Occasionally, a dependency is added or removed, or the import path is changed.
+
+New dependencies require the closest review to ensure the license is acceptable.
+Because we generate the license reports **after** dependencies are changed,
+the new dependency would have already gone through one review when it was initially added.
+This is just a secondary review to double-check the license. If in doubt, ask legal.
+
+Always do a normal GitHub code review on the license PR with a brief summary of what changed.
+For example, see #13936 or #14064. Then approve and merge the PR.

maths/ewma.go

@@ -0,0 +1,72 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package maths contains additional mathematical functions or structures not
+// found in the standard library.
+package maths
+
+import (
+	"math"
+	"time"
+)
+
+// EWMA is an exponentially weighted moving average supporting updates at
+// irregular intervals with at most nanosecond resolution.
+// The zero value will compute a half-life of 1 second.
+// It is not safe for concurrent use.
+// TODO(raggi): de-duplicate with tstime/rate.Value, which has a more complex
+// and synchronized interface and does not provide direct access to the stable
+// value.
+type EWMA struct {
+	value    float64 // current value of the average
+	lastTime int64   // time of last update in unix nanos
+	halfLife float64 // half-life in seconds
+}
+
+// NewEWMA creates a new EWMA with the specified half-life. If halfLifeSeconds
+// is 0, it defaults to 1.
+func NewEWMA(halfLifeSeconds float64) *EWMA {
+	return &EWMA{
+		halfLife: halfLifeSeconds,
+	}
+}
+
+// Update adds a new sample to the average. If t is zero or precedes the last
+// update, the update is ignored.
+func (e *EWMA) Update(value float64, t time.Time) {
+	if t.IsZero() {
+		return
+	}
+	hl := e.halfLife
+	if hl == 0 {
+		hl = 1
+	}
+	tn := t.UnixNano()
+	if e.lastTime == 0 {
+		e.value = value
+		e.lastTime = tn
+		return
+	}
+
+	dt := (time.Duration(tn-e.lastTime) * time.Nanosecond).Seconds()
+	if dt < 0 {
+		// drop out of order updates
+		return
+	}
+
+	// decay = 2^(-dt/halfLife)
+	decay := math.Exp2(-dt / hl)
+	e.value = e.value*decay + value*(1-decay)
+	e.lastTime = tn
+}
+
+// Get returns the current value of the average
+func (e *EWMA) Get() float64 {
+	return e.value
+}
+
+// Reset clears the EWMA to its initial state
+func (e *EWMA) Reset() {
+	e.value = 0
+	e.lastTime = 0
+}

maths/ewma_test.go

@@ -0,0 +1,178 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package maths
+
+import (
+	"slices"
+	"testing"
+	"time"
+)
+
+// some real world latency samples.
+var (
+	latencyHistory1 = []int{
+		14, 12, 15, 6, 19, 12, 13, 13, 13, 16, 17, 11, 17, 11, 14, 15, 14, 15,
+		16, 16, 17, 14, 12, 16, 18, 14, 14, 11, 15, 15, 25, 11, 15, 14, 12, 15,
+		13, 12, 13, 15, 11, 13, 15, 14, 14, 15, 12, 15, 18, 12, 15, 22, 12, 13,
+		10, 14, 16, 15, 16, 11, 14, 17, 18, 20, 16, 11, 16, 14, 5, 15, 17, 12,
+		15, 11, 15, 20, 12, 17, 12, 17, 15, 12, 12, 11, 14, 15, 11, 20, 14, 13,
+		11, 12, 13, 13, 11, 13, 11, 15, 13, 13, 14, 12, 11, 12, 12, 14, 11, 13,
+		12, 12, 12, 19, 14, 13, 13, 14, 11, 12, 10, 11, 15, 12, 14, 11, 11, 14,
+		14, 12, 12, 11, 14, 12, 11, 12, 14, 11, 12, 15, 12, 14, 12, 12, 21, 16,
+		21, 12, 16, 9, 11, 16, 14, 13, 14, 12, 13, 16,
+	}
+	latencyHistory2 = []int{
+		18, 20, 21, 21, 20, 23, 18, 18, 20, 21, 20, 19, 22, 18, 20, 20, 19, 21,
+		21, 22, 22, 19, 18, 22, 22, 19, 20, 17, 16, 11, 25, 16, 18, 21, 17, 22,
+		19, 18, 22, 21, 20, 18, 22, 17, 17, 20, 19, 10, 19, 16, 19, 25, 17, 18,
+		15, 20, 21, 20, 23, 22, 22, 22, 19, 22, 22, 17, 22, 20, 20, 19, 21, 22,
+		20, 19, 17, 22, 16, 16, 20, 22, 17, 19, 21, 16, 20, 22, 19, 21, 20, 19,
+		13, 14, 23, 19, 16, 10, 19, 15, 15, 17, 16, 18, 14, 16, 18, 22, 20, 18,
+		18, 21, 15, 19, 18, 19, 18, 20, 17, 19, 21, 19, 20, 19, 20, 20, 17, 14,
+		17, 17, 18, 21, 20, 18, 18, 17, 16, 17, 17, 20, 22, 19, 20, 21, 21, 20,
+		21, 24, 20, 18, 12, 17, 18, 17, 19, 19, 19,
+	}
+)
+
+func TestEWMALatencyHistory(t *testing.T) {
+	type result struct {
+		t time.Time
+		v float64
+		s int
+	}
+
+	for _, latencyHistory := range [][]int{latencyHistory1, latencyHistory2} {
+		startTime := time.Date(2025, 1, 1, 12, 0, 0, 0, time.UTC)
+		halfLife := 30.0
+
+		ewma := NewEWMA(halfLife)
+
+		var results []result
+		sum := 0.0
+		for i, latency := range latencyHistory {
+			t := startTime.Add(time.Duration(i) * time.Second)
+			ewma.Update(float64(latency), t)
+			sum += float64(latency)
+
+			results = append(results, result{t, ewma.Get(), latency})
+		}
+		mean := sum / float64(len(latencyHistory))
+		min := float64(slices.Min(latencyHistory))
+		max := float64(slices.Max(latencyHistory))
+
+		t.Logf("EWMA Latency History (half-life: %.1f seconds):", halfLife)
+		t.Logf("Mean latency: %.2f ms", mean)
+		t.Logf("Range: [%.1f, %.1f]", min, max)
+
+		t.Log("Samples: ")
+		sparkline := []rune("▁▂▃▄▅▆▇█")
+		var sampleLine []rune
+		for _, r := range results {
+			idx := int(((float64(r.s) - min) / (max - min)) * float64(len(sparkline)-1))
+			if idx >= len(sparkline) {
+				idx = len(sparkline) - 1
+			}
+			sampleLine = append(sampleLine, sparkline[idx])
+		}
+		t.Log(string(sampleLine))
+
+		t.Log("EWMA:    ")
+		var ewmaLine []rune
+		for _, r := range results {
+			idx := int(((r.v - min) / (max - min)) * float64(len(sparkline)-1))
+			if idx >= len(sparkline) {
+				idx = len(sparkline) - 1
+			}
+			ewmaLine = append(ewmaLine, sparkline[idx])
+		}
+		t.Log(string(ewmaLine))
+		t.Log("")
+
+		t.Logf("Time       | Sample | Value  | Value - Sample")
+		t.Logf("")
+
+		for _, result := range results {
+			t.Logf("%10s | % 6d | % 5.2f | % 5.2f", result.t.Format("15:04:05"), result.s, result.v, result.v-float64(result.s))
+		}
+
+		// check that all results are greater than the min, and less than the max of the input,
+		// and they're all close to the mean.
+		for _, result := range results {
+			if result.v < float64(min) || result.v > float64(max) {
+				t.Errorf("result %f out of range [%f, %f]", result.v, min, max)
+			}
+
+			if result.v < mean*0.9 || result.v > mean*1.1 {
+				t.Errorf("result %f not close to mean %f", result.v, mean)
+			}
+		}
+	}
+}
+
+func TestHalfLife(t *testing.T) {
+	start := time.Date(2025, 1, 1, 12, 0, 0, 0, time.UTC)
+
+	ewma := NewEWMA(30.0)
+	ewma.Update(10, start)
+	ewma.Update(0, start.Add(30*time.Second))
+
+	if ewma.Get() != 5 {
+		t.Errorf("expected 5, got %f", ewma.Get())
+	}
+
+	ewma.Update(10, start.Add(60*time.Second))
+	if ewma.Get() != 7.5 {
+		t.Errorf("expected 7.5, got %f", ewma.Get())
+	}
+
+	ewma.Update(10, start.Add(90*time.Second))
+	if ewma.Get() != 8.75 {
+		t.Errorf("expected 8.75, got %f", ewma.Get())
+	}
+}
+
+func TestZeroValue(t *testing.T) {
+	start := time.Date(2025, 1, 1, 12, 0, 0, 0, time.UTC)
+
+	var ewma EWMA
+	ewma.Update(10, start)
+	ewma.Update(0, start.Add(time.Second))
+
+	if ewma.Get() != 5 {
+		t.Errorf("expected 5, got %f", ewma.Get())
+	}
+
+	ewma.Update(10, start.Add(2*time.Second))
+	if ewma.Get() != 7.5 {
+		t.Errorf("expected 7.5, got %f", ewma.Get())
+	}
+
+	ewma.Update(10, start.Add(3*time.Second))
+	if ewma.Get() != 8.75 {
+		t.Errorf("expected 8.75, got %f", ewma.Get())
+	}
+}
+
+func TestReset(t *testing.T) {
+	start := time.Date(2025, 1, 1, 12, 0, 0, 0, time.UTC)
+
+	ewma := NewEWMA(30.0)
+	ewma.Update(10, start)
+	ewma.Update(0, start.Add(30*time.Second))
+
+	if ewma.Get() != 5 {
+		t.Errorf("expected 5, got %f", ewma.Get())
+	}
+
+	ewma.Reset()
+
+	if ewma.Get() != 0 {
+		t.Errorf("expected 0, got %f", ewma.Get())
+	}
+
+	ewma.Update(10, start.Add(90*time.Second))
+	if ewma.Get() != 10 {
+		t.Errorf("expected 10, got %f", ewma.Get())
+	}
+}

net/ktimeout/ktimeout_linux_test.go

@@ -4,17 +4,22 @@
 package ktimeout
 
 import (
+	"context"
 	"net"
 	"testing"
 	"time"
 
-	"golang.org/x/net/nettest"
 	"golang.org/x/sys/unix"
 	"tailscale.com/util/must"
 )
 
 func TestSetUserTimeout(t *testing.T) {
-	l := must.Get(nettest.NewLocalListener("tcp"))
+	lc := net.ListenConfig{}
+	// As of 2025-02-19, MPTCP does not support TCP_USER_TIMEOUT socket option
+	// set in ktimeout.UserTimeout above.
+	lc.SetMultipathTCP(false)
+
+	l := must.Get(lc.Listen(context.Background(), "tcp", "localhost:0"))
 	defer l.Close()
 
 	var err error

safesocket/safesocket_darwin.go

@@ -37,14 +37,16 @@ type safesocketDarwin struct {
 	sameuserproofFD *os.File // file descriptor for macos app store sameuserproof file
 	sharedDir       string   // shared directory for location of sameuserproof file
 
-	checkConn   bool        // Check macsys safesocket port before returning it
-	isMacSysExt func() bool // For testing only to force macsys
+	checkConn        bool        // Check macsys safesocket port before returning it
+	isMacSysExt      func() bool // For testing only to force macsys
+	isSandboxedMacos func() bool // For testing only to force macOS sandbox
 }
 
 var ssd = safesocketDarwin{
-	isMacSysExt: version.IsMacSysExt,
-	checkConn:   true,
-	sharedDir:   "/Library/Tailscale",
+	isMacSysExt:      version.IsMacSysExt,
+	isSandboxedMacos: version.IsSandboxedMacOS,
+	checkConn:        true,
+	sharedDir:        "/Library/Tailscale",
 }
 
 // There are three ways a Darwin binary can be run: as the Mac App Store (macOS)
@@ -66,6 +68,10 @@ func localTCPPortAndTokenDarwin() (port int, token string, err error) {
 	ssd.mu.Lock()
 	defer ssd.mu.Unlock()
 
+	if !ssd.isSandboxedMacos() {
+		return 0, "", ErrNoTokenOnOS
+	}
+
 	if ssd.port != 0 && ssd.token != "" {
 		return ssd.port, ssd.token, nil
 	}

safesocket/safesocket_darwin_test.go

@@ -17,6 +17,7 @@ import (
 func TestSetCredentials(t *testing.T) {
 	wantPort := 123
 	wantToken := "token"
+	tstest.Replace(t, &ssd.isSandboxedMacos, func() bool { return true })
 	SetCredentials(wantToken, wantPort)
 
 	gotPort, gotToken, err := LocalTCPPortAndToken()
@@ -37,6 +38,8 @@ func TestSetCredentials(t *testing.T) {
 // returns a listener and a non-zero port and non-empty token.
 func TestInitListenerDarwin(t *testing.T) {
 	temp := t.TempDir()
+	tstest.Replace(t, &ssd.isSandboxedMacos, func() bool { return true })
+
 	ln, err := InitListenerDarwin(temp)
 	if err != nil || ln == nil {
 		t.Fatalf("InitListenerDarwin failed: %v", err)

scripts/installer.sh

@@ -186,6 +186,12 @@ main() {
 					VERSION="$DEBIAN_CODENAME"
 				fi
 				;;
+			sparky)
+				OS="debian"
+				PACKAGETYPE="apt"
+				VERSION="$DEBIAN_CODENAME"
+				APT_KEY_TYPE="keyring"
+				;;
 			centos)
 				OS="$ID"
 				VERSION="$VERSION_ID"
@@ -487,10 +493,13 @@ main() {
 				legacy)
 					$CURL "https://pkgs.tailscale.com/$TRACK/$OS/$VERSION.asc" | $SUDO apt-key add -
 					$CURL "https://pkgs.tailscale.com/$TRACK/$OS/$VERSION.list" | $SUDO tee /etc/apt/sources.list.d/tailscale.list
+					$SUDO chmod 0644 /etc/apt/sources.list.d/tailscale.list
 				;;
 				keyring)
 					$CURL "https://pkgs.tailscale.com/$TRACK/$OS/$VERSION.noarmor.gpg" | $SUDO tee /usr/share/keyrings/tailscale-archive-keyring.gpg >/dev/null
+					$SUDO chmod 0644 /usr/share/keyrings/tailscale-archive-keyring.gpg
 					$CURL "https://pkgs.tailscale.com/$TRACK/$OS/$VERSION.tailscale-keyring.list" | $SUDO tee /etc/apt/sources.list.d/tailscale.list
+					$SUDO chmod 0644 /etc/apt/sources.list.d/tailscale.list
 				;;
 			esac
 			$SUDO apt-get update

tempfork/acme/acme.go

@@ -557,7 +557,11 @@ func (c *Client) Accept(ctx context.Context, chal *Challenge) (*Challenge, error
 		return nil, err
 	}
 
-	res, err := c.post(ctx, nil, chal.URI, json.RawMessage("{}"), wantStatus(
+	payload := json.RawMessage("{}")
+	if len(chal.Payload) != 0 {
+		payload = chal.Payload
+	}
+	res, err := c.post(ctx, nil, chal.URI, payload, wantStatus(
 		http.StatusOK,       // according to the spec
 		http.StatusAccepted, // Let's Encrypt: see https://goo.gl/WsJ7VT (acme-divergences.md)
 	))

tempfork/acme/acme_test.go

@@ -875,7 +875,7 @@ func TestTLSALPN01ChallengeCert(t *testing.T) {
 }
 
 func TestTLSChallengeCertOpt(t *testing.T) {
-	key, err := rsa.GenerateKey(rand.Reader, 512)
+	key, err := rsa.GenerateKey(rand.Reader, 1024)
 	if err != nil {
 		t.Fatal(err)
 	}

tempfork/acme/http.go

@@ -15,6 +15,7 @@ import (
 	"io"
 	"math/big"
 	"net/http"
+	"runtime/debug"
 	"strconv"
 	"strings"
 	"time"
@@ -271,9 +272,27 @@ func (c *Client) httpClient() *http.Client {
 }
 
 // packageVersion is the version of the module that contains this package, for
-// sending as part of the User-Agent header. It's set in version_go112.go.
+// sending as part of the User-Agent header.
 var packageVersion string
 
+func init() {
+	// Set packageVersion if the binary was built in modules mode and x/crypto
+	// was not replaced with a different module.
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return
+	}
+	for _, m := range info.Deps {
+		if m.Path != "golang.org/x/crypto" {
+			continue
+		}
+		if m.Replace == nil {
+			packageVersion = m.Version
+		}
+		break
+	}
+}
+
 // userAgent returns the User-Agent header value. It includes the package name,
 // the module version (if available), and the c.UserAgent value (if set).
 func (c *Client) userAgent() string {

tempfork/acme/types.go

@@ -7,6 +7,7 @@ package acme
 import (
 	"crypto"
 	"crypto/x509"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"net/http"
@@ -292,7 +293,7 @@ type Directory struct {
 	// Renewal Information (ARI) Extension.
 	RenewalInfoURL string
 
-	// Term is a URI identifying the current terms of service.
+	// Terms is a URI identifying the current terms of service.
 	Terms string
 
 	// Website is an HTTP or HTTPS URL locating a website
@@ -531,6 +532,16 @@ type Challenge struct {
 	// when this challenge was used.
 	// The type of a non-nil value is *Error.
 	Error error
+
+	// Payload is the JSON-formatted payload that the client sends
+	// to the server to indicate it is ready to respond to the challenge.
+	// When unset, it defaults to an empty JSON object: {}.
+	// For most challenges, the client must not set Payload,
+	// see https://tools.ietf.org/html/rfc8555#section-7.5.1.
+	// Payload is used only for newer challenges (such as "device-attest-01")
+	// where the client must send additional data for the server to validate
+	// the challenge.
+	Payload json.RawMessage
 }
 
 // wireChallenge is ACME JSON challenge representation.

tstest/deptest/deptest.go

@@ -27,6 +27,7 @@ type DepChecker struct {
 	BadDeps  map[string]string // package => why
 	WantDeps set.Set[string]   // packages expected
 	Tags     string            // comma-separated
+	ExtraEnv []string          // extra environment for "go list" (e.g. CGO_ENABLED=1)
 }
 
 func (c DepChecker) Check(t *testing.T) {
@@ -43,6 +44,7 @@ func (c DepChecker) Check(t *testing.T) {
 	if c.GOARCH != "" {
 		extraEnv = append(extraEnv, "GOARCH="+c.GOARCH)
 	}
+	extraEnv = append(extraEnv, c.ExtraEnv...)
 	cmd.Env = append(os.Environ(), extraEnv...)
 	out, err := cmd.Output()
 	if err != nil {

types/opt/value.go

@@ -100,31 +100,31 @@ func (o Value[T]) Equal(v Value[T]) bool {
 	return false
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (o Value[T]) MarshalJSONV2(enc *jsontext.Encoder, opts jsonv2.Options) error {
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (o Value[T]) MarshalJSONTo(enc *jsontext.Encoder) error {
 	if !o.set {
 		return enc.WriteToken(jsontext.Null)
 	}
-	return jsonv2.MarshalEncode(enc, &o.value, opts)
+	return jsonv2.MarshalEncode(enc, &o.value)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (o *Value[T]) UnmarshalJSONV2(dec *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (o *Value[T]) UnmarshalJSONFrom(dec *jsontext.Decoder) error {
 	if dec.PeekKind() == 'n' {
 		*o = Value[T]{}
 		_, err := dec.ReadToken() // read null
 		return err
 	}
 	o.set = true
-	return jsonv2.UnmarshalDecode(dec, &o.value, opts)
+	return jsonv2.UnmarshalDecode(dec, &o.value)
 }
 
 // MarshalJSON implements [json.Marshaler].
 func (o Value[T]) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(o) // uses MarshalJSONV2
+	return jsonv2.Marshal(o) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (o *Value[T]) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, o) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, o) // uses UnmarshalJSONFrom
 }

types/opt/value_test.go

@@ -13,6 +13,11 @@ import (
 	"tailscale.com/util/must"
 )
 
+var (
+	_ jsonv2.MarshalerTo     = (*Value[bool])(nil)
+	_ jsonv2.UnmarshalerFrom = (*Value[bool])(nil)
+)
+
 type testStruct struct {
 	Int int    `json:",omitempty,omitzero"`
 	Str string `json:",omitempty"`

types/prefs/item.go

@@ -152,15 +152,15 @@ func (iv ItemView[T, V]) Equal(iv2 ItemView[T, V]) bool {
 	return iv.ж.Equal(*iv2.ж)
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (iv ItemView[T, V]) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return iv.ж.MarshalJSONV2(out, opts)
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (iv ItemView[T, V]) MarshalJSONTo(out *jsontext.Encoder) error {
+	return iv.ж.MarshalJSONTo(out)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (iv *ItemView[T, V]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (iv *ItemView[T, V]) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	var x Item[T]
-	if err := x.UnmarshalJSONV2(in, opts); err != nil {
+	if err := x.UnmarshalJSONFrom(in); err != nil {
 		return err
 	}
 	iv.ж = &x
@@ -169,10 +169,10 @@ func (iv *ItemView[T, V]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Opti
 
 // MarshalJSON implements [json.Marshaler].
 func (iv ItemView[T, V]) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(iv) // uses MarshalJSONV2
+	return jsonv2.Marshal(iv) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (iv *ItemView[T, V]) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, iv) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, iv) // uses UnmarshalJSONFrom
 }

types/prefs/list.go

@@ -157,15 +157,20 @@ func (lv ListView[T]) Equal(lv2 ListView[T]) bool {
 	return lv.ж.Equal(*lv2.ж)
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (lv ListView[T]) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return lv.ж.MarshalJSONV2(out, opts)
+var (
+	_ jsonv2.MarshalerTo     = (*ListView[bool])(nil)
+	_ jsonv2.UnmarshalerFrom = (*ListView[bool])(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (lv ListView[T]) MarshalJSONTo(out *jsontext.Encoder) error {
+	return lv.ж.MarshalJSONTo(out)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (lv *ListView[T]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (lv *ListView[T]) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	var x List[T]
-	if err := x.UnmarshalJSONV2(in, opts); err != nil {
+	if err := x.UnmarshalJSONFrom(in); err != nil {
 		return err
 	}
 	lv.ж = &x
@@ -174,10 +179,10 @@ func (lv *ListView[T]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options
 
 // MarshalJSON implements [json.Marshaler].
 func (lv ListView[T]) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(lv) // uses MarshalJSONV2
+	return jsonv2.Marshal(lv) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (lv *ListView[T]) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, lv) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, lv) // uses UnmarshalJSONFrom
 }

types/prefs/map.go

@@ -133,15 +133,15 @@ func (mv MapView[K, V]) Equal(mv2 MapView[K, V]) bool {
 	return mv.ж.Equal(*mv2.ж)
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (mv MapView[K, V]) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return mv.ж.MarshalJSONV2(out, opts)
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (mv MapView[K, V]) MarshalJSONTo(out *jsontext.Encoder) error {
+	return mv.ж.MarshalJSONTo(out)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (mv *MapView[K, V]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (mv *MapView[K, V]) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	var x Map[K, V]
-	if err := x.UnmarshalJSONV2(in, opts); err != nil {
+	if err := x.UnmarshalJSONFrom(in); err != nil {
 		return err
 	}
 	mv.ж = &x
@@ -150,10 +150,10 @@ func (mv *MapView[K, V]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Optio
 
 // MarshalJSON implements [json.Marshaler].
 func (mv MapView[K, V]) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(mv) // uses MarshalJSONV2
+	return jsonv2.Marshal(mv) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (mv *MapView[K, V]) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, mv) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, mv) // uses UnmarshalJSONFrom
 }

types/prefs/prefs.go

@@ -158,22 +158,27 @@ func (p *preference[T]) SetReadOnly(readonly bool) {
 	p.s.Metadata.ReadOnly = readonly
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (p preference[T]) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return jsonv2.MarshalEncode(out, &p.s, opts)
+var (
+	_ jsonv2.MarshalerTo     = (*preference[struct{}])(nil)
+	_ jsonv2.UnmarshalerFrom = (*preference[struct{}])(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (p preference[T]) MarshalJSONTo(out *jsontext.Encoder) error {
+	return jsonv2.MarshalEncode(out, &p.s)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (p *preference[T]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
-	return jsonv2.UnmarshalDecode(in, &p.s, opts)
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (p *preference[T]) UnmarshalJSONFrom(in *jsontext.Decoder) error {
+	return jsonv2.UnmarshalDecode(in, &p.s)
 }
 
 // MarshalJSON implements [json.Marshaler].
 func (p preference[T]) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(p) // uses MarshalJSONV2
+	return jsonv2.Marshal(p) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (p *preference[T]) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, p) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, p) // uses UnmarshalJSONFrom
 }

types/prefs/prefs_example/prefs_types.go

@@ -48,10 +48,10 @@ import (
 // the `omitzero` JSON tag option. This option is not supported by the
 // [encoding/json] package as of 2024-08-21; see golang/go#45669.
 // It is recommended that a prefs type implements both
-// [jsonv2.MarshalerV2]/[jsonv2.UnmarshalerV2] and [json.Marshaler]/[json.Unmarshaler]
+// [jsonv2.MarshalerTo]/[jsonv2.UnmarshalerFrom] and [json.Marshaler]/[json.Unmarshaler]
 // to ensure consistent and more performant marshaling, regardless of the JSON package
 // used at the call sites; the standard marshalers can be implemented via [jsonv2].
-// See [Prefs.MarshalJSONV2], [Prefs.UnmarshalJSONV2], [Prefs.MarshalJSON],
+// See [Prefs.MarshalJSONTo], [Prefs.UnmarshalJSONFrom], [Prefs.MarshalJSON],
 // and [Prefs.UnmarshalJSON] for an example implementation.
 type Prefs struct {
 	ControlURL prefs.Item[string]               `json:",omitzero"`
@@ -128,34 +128,39 @@ type AppConnectorPrefs struct {
 	Advertise prefs.Item[bool] `json:",omitzero"`
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
+var (
+	_ jsonv2.MarshalerTo     = (*Prefs)(nil)
+	_ jsonv2.UnmarshalerFrom = (*Prefs)(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
 // It is implemented as a performance improvement and to enable omission of
 // unconfigured preferences from the JSON output. See the [Prefs] doc for details.
-func (p Prefs) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
+func (p Prefs) MarshalJSONTo(out *jsontext.Encoder) error {
 	// The prefs type shadows the Prefs's method set,
 	// causing [jsonv2] to use the default marshaler and avoiding
 	// infinite recursion.
 	type prefs Prefs
-	return jsonv2.MarshalEncode(out, (*prefs)(&p), opts)
+	return jsonv2.MarshalEncode(out, (*prefs)(&p))
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (p *Prefs) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (p *Prefs) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	// The prefs type shadows the Prefs's method set,
 	// causing [jsonv2] to use the default unmarshaler and avoiding
 	// infinite recursion.
 	type prefs Prefs
-	return jsonv2.UnmarshalDecode(in, (*prefs)(p), opts)
+	return jsonv2.UnmarshalDecode(in, (*prefs)(p))
 }
 
 // MarshalJSON implements [json.Marshaler].
 func (p Prefs) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(p) // uses MarshalJSONV2
+	return jsonv2.Marshal(p) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (p *Prefs) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, p) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, p) // uses UnmarshalJSONFrom
 }
 
 type marshalAsTrueInJSON struct{}

types/prefs/prefs_test.go

@@ -19,6 +19,20 @@ import (
 
 //go:generate go run tailscale.com/cmd/viewer --tags=test --type=TestPrefs,TestBundle,TestValueStruct,TestGenericStruct,TestPrefsGroup
 
+var (
+	_ jsonv2.MarshalerTo     = (*ItemView[*TestBundle, TestBundleView])(nil)
+	_ jsonv2.UnmarshalerFrom = (*ItemView[*TestBundle, TestBundleView])(nil)
+
+	_ jsonv2.MarshalerTo     = (*MapView[string, string])(nil)
+	_ jsonv2.UnmarshalerFrom = (*MapView[string, string])(nil)
+
+	_ jsonv2.MarshalerTo     = (*StructListView[*TestBundle, TestBundleView])(nil)
+	_ jsonv2.UnmarshalerFrom = (*StructListView[*TestBundle, TestBundleView])(nil)
+
+	_ jsonv2.MarshalerTo     = (*StructMapView[string, *TestBundle, TestBundleView])(nil)
+	_ jsonv2.UnmarshalerFrom = (*StructMapView[string, *TestBundle, TestBundleView])(nil)
+)
+
 type TestPrefs struct {
 	Int32Item   Item[int32]  `json:",omitzero"`
 	UInt64Item  Item[uint64] `json:",omitzero"`
@@ -53,32 +67,37 @@ type TestPrefs struct {
 	Group TestPrefsGroup `json:",omitzero"`
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (p TestPrefs) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
+var (
+	_ jsonv2.MarshalerTo     = (*TestPrefs)(nil)
+	_ jsonv2.UnmarshalerFrom = (*TestPrefs)(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (p TestPrefs) MarshalJSONTo(out *jsontext.Encoder) error {
 	// The testPrefs type shadows the TestPrefs's method set,
 	// causing jsonv2 to use the default marshaler and avoiding
 	// infinite recursion.
 	type testPrefs TestPrefs
-	return jsonv2.MarshalEncode(out, (*testPrefs)(&p), opts)
+	return jsonv2.MarshalEncode(out, (*testPrefs)(&p))
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (p *TestPrefs) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (p *TestPrefs) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	// The testPrefs type shadows the TestPrefs's method set,
 	// causing jsonv2 to use the default unmarshaler and avoiding
 	// infinite recursion.
 	type testPrefs TestPrefs
-	return jsonv2.UnmarshalDecode(in, (*testPrefs)(p), opts)
+	return jsonv2.UnmarshalDecode(in, (*testPrefs)(p))
 }
 
 // MarshalJSON implements [json.Marshaler].
 func (p TestPrefs) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(p) // uses MarshalJSONV2
+	return jsonv2.Marshal(p) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (p *TestPrefs) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, p) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, p) // uses UnmarshalJSONFrom
 }
 
 // TestBundle is an example structure type that,

types/prefs/struct_list.go

@@ -169,15 +169,15 @@ func (lv StructListView[T, V]) Equal(lv2 StructListView[T, V]) bool {
 	return lv.ж.Equal(*lv2.ж)
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (lv StructListView[T, V]) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return lv.ж.MarshalJSONV2(out, opts)
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (lv StructListView[T, V]) MarshalJSONTo(out *jsontext.Encoder) error {
+	return lv.ж.MarshalJSONTo(out)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (lv *StructListView[T, V]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (lv *StructListView[T, V]) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	var x StructList[T]
-	if err := x.UnmarshalJSONV2(in, opts); err != nil {
+	if err := x.UnmarshalJSONFrom(in); err != nil {
 		return err
 	}
 	lv.ж = &x
@@ -186,10 +186,10 @@ func (lv *StructListView[T, V]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv
 
 // MarshalJSON implements [json.Marshaler].
 func (lv StructListView[T, V]) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(lv) // uses MarshalJSONV2
+	return jsonv2.Marshal(lv) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (lv *StructListView[T, V]) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, lv) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, lv) // uses UnmarshalJSONFrom
 }

types/prefs/struct_map.go

@@ -149,15 +149,15 @@ func (mv StructMapView[K, T, V]) Equal(mv2 StructMapView[K, T, V]) bool {
 	return mv.ж.Equal(*mv2.ж)
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (mv StructMapView[K, T, V]) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return mv.ж.MarshalJSONV2(out, opts)
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (mv StructMapView[K, T, V]) MarshalJSONTo(out *jsontext.Encoder) error {
+	return mv.ж.MarshalJSONTo(out)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (mv *StructMapView[K, T, V]) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (mv *StructMapView[K, T, V]) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	var x StructMap[K, T]
-	if err := x.UnmarshalJSONV2(in, opts); err != nil {
+	if err := x.UnmarshalJSONFrom(in); err != nil {
 		return err
 	}
 	mv.ж = &x
@@ -166,10 +166,10 @@ func (mv *StructMapView[K, T, V]) UnmarshalJSONV2(in *jsontext.Decoder, opts jso
 
 // MarshalJSON implements [json.Marshaler].
 func (mv StructMapView[K, T, V]) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(mv) // uses MarshalJSONV2
+	return jsonv2.Marshal(mv) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (mv *StructMapView[K, T, V]) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, mv) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, mv) // uses UnmarshalJSONFrom
 }

util/eventbus/bus.go

@@ -0,0 +1,223 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package eventbus
+
+import (
+	"context"
+	"reflect"
+	"slices"
+	"sync"
+
+	"tailscale.com/util/set"
+)
+
+// Bus is an event bus that distributes published events to interested
+// subscribers.
+type Bus struct {
+	write    chan any
+	stop     goroutineShutdownControl
+	snapshot chan chan []any
+
+	topicsMu sync.Mutex // guards everything below.
+	topics   map[reflect.Type][]*Queue
+
+	// Used for introspection/debugging only, not in the normal event
+	// publishing path.
+	publishers set.Set[publisher]
+	queues     set.Set[*Queue]
+}
+
+// New returns a new bus. Use [PublisherOf] to make event publishers,
+// and [Bus.Queue] and [Subscribe] to make event subscribers.
+func New() *Bus {
+	stopCtl, stopWorker := newGoroutineShutdown()
+	ret := &Bus{
+		write:      make(chan any),
+		stop:       stopCtl,
+		snapshot:   make(chan chan []any),
+		topics:     map[reflect.Type][]*Queue{},
+		publishers: set.Set[publisher]{},
+		queues:     set.Set[*Queue]{},
+	}
+	go ret.pump(stopWorker)
+	return ret
+}
+
+func (b *Bus) pump(stop goroutineShutdownWorker) {
+	defer stop.Done()
+	var vals queue
+	acceptCh := func() chan any {
+		if vals.Full() {
+			return nil
+		}
+		return b.write
+	}
+	for {
+		// Drain all pending events. Note that while we're draining
+		// events into subscriber queues, we continue to
+		// opportunistically accept more incoming events, if we have
+		// queue space for it.
+		for !vals.Empty() {
+			val := vals.Peek()
+			dests := b.dest(reflect.ValueOf(val).Type())
+			for _, d := range dests {
+			deliverOne:
+				for {
+					select {
+					case d.write <- val:
+						break deliverOne
+					case <-d.stop.WaitChan():
+						// Queue closed, don't block but continue
+						// delivering to others.
+						break deliverOne
+					case in := <-acceptCh():
+						vals.Add(in)
+					case <-stop.Stop():
+						return
+					case ch := <-b.snapshot:
+						ch <- vals.Snapshot()
+					}
+				}
+			}
+			vals.Drop()
+		}
+
+		// Inbound queue empty, wait for at least 1 work item before
+		// resuming.
+		for vals.Empty() {
+			select {
+			case <-stop.Stop():
+				return
+			case val := <-b.write:
+				vals.Add(val)
+			case ch := <-b.snapshot:
+				ch <- nil
+			}
+		}
+	}
+}
+
+func (b *Bus) dest(t reflect.Type) []*Queue {
+	b.topicsMu.Lock()
+	defer b.topicsMu.Unlock()
+	return b.topics[t]
+}
+
+func (b *Bus) subscribe(t reflect.Type, q *Queue) (cancel func()) {
+	b.topicsMu.Lock()
+	defer b.topicsMu.Unlock()
+	b.topics[t] = append(b.topics[t], q)
+	return func() {
+		b.unsubscribe(t, q)
+	}
+}
+
+func (b *Bus) unsubscribe(t reflect.Type, q *Queue) {
+	b.topicsMu.Lock()
+	defer b.topicsMu.Unlock()
+	// Topic slices are accessed by pump without holding a lock, so we
+	// have to replace the entire slice when unsubscribing.
+	// Unsubscribing should be infrequent enough that this won't
+	// matter.
+	i := slices.Index(b.topics[t], q)
+	if i < 0 {
+		return
+	}
+	b.topics[t] = slices.Delete(slices.Clone(b.topics[t]), i, i+1)
+}
+
+func (b *Bus) Close() {
+	b.stop.StopAndWait()
+}
+
+// Queue returns a new queue with no subscriptions. Use [Subscribe] to
+// atach subscriptions to it.
+//
+// The queue's name should be a short, human-readable string that
+// identifies this queue. The name is only visible through debugging
+// APIs.
+func (b *Bus) Queue(name string) *Queue {
+	return newQueue(b, name)
+}
+
+func (b *Bus) addQueue(q *Queue) {
+	b.topicsMu.Lock()
+	defer b.topicsMu.Unlock()
+	b.queues.Add(q)
+}
+
+func (b *Bus) deleteQueue(q *Queue) {
+	b.topicsMu.Lock()
+	defer b.topicsMu.Unlock()
+	b.queues.Delete(q)
+}
+
+func (b *Bus) addPublisher(p publisher) {
+	b.topicsMu.Lock()
+	defer b.topicsMu.Unlock()
+	b.publishers.Add(p)
+}
+
+func (b *Bus) deletePublisher(p publisher) {
+	b.topicsMu.Lock()
+	defer b.topicsMu.Unlock()
+	b.publishers.Delete(p)
+}
+
+func newGoroutineShutdown() (goroutineShutdownControl, goroutineShutdownWorker) {
+	ctx, cancel := context.WithCancel(context.Background())
+
+	ctl := goroutineShutdownControl{
+		startShutdown:    cancel,
+		shutdownFinished: make(chan struct{}),
+	}
+	work := goroutineShutdownWorker{
+		startShutdown:    ctx.Done(),
+		shutdownFinished: ctl.shutdownFinished,
+	}
+
+	return ctl, work
+}
+
+// goroutineShutdownControl is a helper type to manage the shutdown of
+// a worker goroutine. The worker goroutine should use the
+// goroutineShutdownWorker related to this controller.
+type goroutineShutdownControl struct {
+	startShutdown    context.CancelFunc
+	shutdownFinished chan struct{}
+}
+
+func (ctl *goroutineShutdownControl) Stop() {
+	ctl.startShutdown()
+}
+
+func (ctl *goroutineShutdownControl) Wait() {
+	<-ctl.shutdownFinished
+}
+
+func (ctl *goroutineShutdownControl) WaitChan() <-chan struct{} {
+	return ctl.shutdownFinished
+}
+
+func (ctl *goroutineShutdownControl) StopAndWait() {
+	ctl.Stop()
+	ctl.Wait()
+}
+
+// goroutineShutdownWorker is a helper type for a worker goroutine to
+// be notified that it should shut down, and to report that shutdown
+// has completed. The notification is triggered by the related
+// goroutineShutdownControl.
+type goroutineShutdownWorker struct {
+	startShutdown    <-chan struct{}
+	shutdownFinished chan struct{}
+}
+
+func (work *goroutineShutdownWorker) Stop() <-chan struct{} {
+	return work.startShutdown
+}
+
+func (work *goroutineShutdownWorker) Done() {
+	close(work.shutdownFinished)
+}

util/eventbus/bus_test.go

@@ -0,0 +1,196 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package eventbus_test
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/creachadair/taskgroup"
+	"github.com/google/go-cmp/cmp"
+	"tailscale.com/util/eventbus"
+)
+
+type EventA struct {
+	Counter int
+}
+
+type EventB struct {
+	Counter int
+}
+
+func TestBus(t *testing.T) {
+	b := eventbus.New()
+	defer b.Close()
+
+	q := b.Queue("TestBus")
+	defer q.Close()
+	s := eventbus.Subscribe[EventA](q)
+
+	go func() {
+		pa := eventbus.PublisherOf[EventA](b, "TestBusA")
+		defer pa.Close()
+		pb := eventbus.PublisherOf[EventB](b, "TestBusB")
+		defer pb.Close()
+		pa.Publish(EventA{1})
+		pb.Publish(EventB{2})
+		pa.Publish(EventA{3})
+	}()
+
+	want := expectEvents(t, EventA{1}, EventA{3})
+	for !want.Empty() {
+		select {
+		case got := <-s.Events():
+			want.Got(got)
+		case <-q.Done():
+			t.Fatalf("queue closed unexpectedly")
+		case <-time.After(time.Second):
+			t.Fatalf("timed out waiting for event")
+		}
+	}
+}
+
+func TestBusMultipleConsumers(t *testing.T) {
+	b := eventbus.New()
+	defer b.Close()
+
+	q1 := b.Queue("TestBusA")
+	defer q1.Close()
+	s1 := eventbus.Subscribe[EventA](q1)
+
+	q2 := b.Queue("TestBusAB")
+	defer q2.Close()
+	s2A := eventbus.Subscribe[EventA](q2)
+	s2B := eventbus.Subscribe[EventB](q2)
+
+	go func() {
+		pa := eventbus.PublisherOf[EventA](b, "TestBusA")
+		defer pa.Close()
+		pb := eventbus.PublisherOf[EventB](b, "TestBusB")
+		defer pb.Close()
+		pa.Publish(EventA{1})
+		pb.Publish(EventB{2})
+		pa.Publish(EventA{3})
+	}()
+
+	wantA := expectEvents(t, EventA{1}, EventA{3})
+	wantB := expectEvents(t, EventA{1}, EventB{2}, EventA{3})
+	for !wantA.Empty() || !wantB.Empty() {
+		select {
+		case got := <-s1.Events():
+			wantA.Got(got)
+		case got := <-s2A.Events():
+			wantB.Got(got)
+		case got := <-s2B.Events():
+			wantB.Got(got)
+		case <-q1.Done():
+			t.Fatalf("queue closed unexpectedly")
+		case <-q2.Done():
+			t.Fatalf("queue closed unexpectedly")
+		case <-time.After(time.Second):
+			t.Fatalf("timed out waiting for event")
+		}
+	}
+}
+
+func TestSpam(t *testing.T) {
+	b := eventbus.New()
+	defer b.Close()
+
+	const (
+		publishers         = 100
+		eventsPerPublisher = 20
+		wantEvents         = publishers * eventsPerPublisher
+		subscribers        = 100
+	)
+
+	var g taskgroup.Group
+
+	received := make([][]EventA, subscribers)
+	for i := range subscribers {
+		q := b.Queue(fmt.Sprintf("Subscriber%d", i))
+		defer q.Close()
+		s := eventbus.Subscribe[EventA](q)
+		g.Go(func() error {
+			for range wantEvents {
+				select {
+				case evt := <-s.Events():
+					received[i] = append(received[i], evt)
+				case <-q.Done():
+					t.Errorf("queue done before expected number of events received")
+					return errors.New("queue prematurely closed")
+				case <-time.After(5 * time.Second):
+					t.Errorf("timed out waiting for expected bus event after %d events", len(received[i]))
+					return errors.New("timeout")
+				}
+			}
+			return nil
+		})
+	}
+
+	published := make([][]EventA, publishers)
+	for i := range publishers {
+		g.Run(func() {
+			p := eventbus.PublisherOf[EventA](b, fmt.Sprintf("Publisher%d", i))
+			for j := range eventsPerPublisher {
+				evt := EventA{i*eventsPerPublisher + j}
+				p.Publish(evt)
+				published[i] = append(published[i], evt)
+			}
+		})
+	}
+
+	if err := g.Wait(); err != nil {
+		t.Fatal(err)
+	}
+	var last []EventA
+	for i, got := range received {
+		if len(got) != wantEvents {
+			// Receiving goroutine already reported an error, we just need
+			// to fail early within the main test goroutine.
+			t.FailNow()
+		}
+		if last == nil {
+			continue
+		}
+		if diff := cmp.Diff(got, last); diff != "" {
+			t.Errorf("Subscriber %d did not see the same events as %d (-got+want):\n%s", i, i-1, diff)
+		}
+		last = got
+	}
+	for i, sent := range published {
+		if got := len(sent); got != eventsPerPublisher {
+			t.Fatalf("Publisher %d sent %d events, want %d", i, got, eventsPerPublisher)
+		}
+	}
+
+	// TODO: check that the published sequences are proper
+	// subsequences of the received slices.
+}
+
+type queueChecker struct {
+	t    *testing.T
+	want []any
+}
+
+func expectEvents(t *testing.T, want ...any) *queueChecker {
+	return &queueChecker{t, want}
+}
+
+func (q *queueChecker) Got(v any) {
+	q.t.Helper()
+	if q.Empty() {
+		q.t.Fatalf("queue got unexpected %v", v)
+	}
+	if v != q.want[0] {
+		q.t.Fatalf("queue got %#v, want %#v", v, q.want[0])
+	}
+	q.want = q.want[1:]
+}
+
+func (q *queueChecker) Empty() bool {
+	return len(q.want) == 0
+}

util/eventbus/doc.go

@@ -0,0 +1,100 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package eventbus provides an in-process event bus.
+//
+// The event bus connects publishers of typed events with subscribers
+// interested in those events.
+//
+// # Usage
+//
+// To publish events, use [PublisherOf] to get a typed publisher for
+// your event type, then call [Publisher.Publish] as needed. If your
+// event is expensive to construct, you can optionally use
+// [Publisher.ShouldPublish] to skip the work if nobody is listening
+// for the event.
+//
+// To receive events, first use [Bus.Queue] to create an event
+// delivery queue, then use [Subscribe] to get a [Subscriber] for each
+// event type you're interested in. Receive the events themselves by
+// selecting over all your [Subscriber.Chan] channels, as well as
+// [Queue.Done] for shutdown notifications.
+//
+// # Concurrency properties
+//
+// The bus serializes all published events, and preserves that
+// ordering when delivering to subscribers that are attached to the
+// same Queue. In more detail:
+//
+//   - An event is published to the bus at some instant between the
+//     start and end of the call to [Publisher.Publish].
+//   - Events cannot be published at the same instant, and so are
+//     totally ordered by their publication time. Given two events E1
+//     and E2, either E1 happens before E2, or E2 happens before E1.
+//   - Queues dispatch events to their Subscribers in publication
+//     order: if E1 happens before E2, the queue always delivers E1
+//     before E2.
+//   - Queues do not synchronize with each other: given queues Q1 and
+//     Q2, both subscribed to events E1 and E2, Q1 may deliver both E1
+//     and E2 before Q2 delivers E1.
+//
+// Less formally: there is one true timeline of all published events.
+// If you make a Queue and subscribe to events on it, you will receive
+// those events one at a time, in the same order as the one true
+// timeline. You will "skip over" events you didn't subscribe to, but
+// your view of the world always moves forward in time, never
+// backwards, and you will observe events in the same order as
+// everyone else.
+//
+// However, you cannot assume that what your subscribers on your queue
+// see as "now" is the same as what other subscribers on other
+// queues. Their queue may be further behind you in the timeline, or
+// running ahead of you. This means you should be careful about
+// reaching out to another component directly after receiving an
+// event, as its view of the world may not yet (or ever) be exactly
+// consistent with yours.
+//
+// To make your code more testable and understandable, you should try
+// to structure it following the actor model: you have some local
+// state over which you have authority, but your only way to interact
+// with state elsewhere in the program is to receive and process
+// events coming from elsewhere, or to emit events of your own.
+//
+// # Expected subscriber behavior
+//
+// Subscribers are expected to promptly receive their events on
+// [Subscriber.Chan]. The bus has a small, fixed amount of internal
+// buffering, meaning that a slow subscriber will eventually cause
+// backpressure and block publication of all further events.
+//
+// In general, you should receive from your subscriber(s) in a loop,
+// and only do fast state updates within that loop. Any heavier work
+// should be offloaded to another goroutine.
+//
+// Causing publishers to block from backpressure is considered a bug
+// in the slow subscriber causing the backpressure, and should be
+// addressed there. Publishers should assume that Publish will not
+// block for extended periods of time, and should not make exceptional
+// effort to behave gracefully if they do get blocked.
+//
+// These blocking semantics are provisional and subject to
+// change. Please speak up if this causes development pain, so that we
+// can adapt the semantics to better suit our needs.
+//
+// # Debugging facilities
+//
+// (TODO, not implemented yet, sorry, I promise we're working on it next!)
+//
+// The bus comes with introspection facilities to help reason about
+// the state of the client, and diagnose issues such as slow
+// subscribers.
+//
+// The bus provide a tsweb debugging page that shows the current state
+// of the bus, including all publishers, subscribers, and queued
+// events.
+//
+// The bus also has a snooping and tracing facility, which lets you
+// observe all events flowing through the bus, along with their
+// source, destination(s) and timing information such as the time of
+// delivery to each subscriber and end-to-end bus delays.
+package eventbus

util/eventbus/publish.go

@@ -0,0 +1,79 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package eventbus
+
+import (
+	"context"
+	"reflect"
+)
+
+// publisher is a uniformly typed wrapper around Publisher[T], so that
+// debugging facilities can look at active publishers.
+type publisher interface {
+	publisherName() string
+}
+
+// A Publisher publishes events on the bus.
+type Publisher[T any] struct {
+	bus     *Bus
+	name    string
+	stopCtx context.Context
+	stop    context.CancelFunc
+}
+
+// PublisherOf returns a publisher for event type T on the given bus.
+//
+// The publisher's name should be a short, human-readable string that
+// identifies this event publisher. The name is only visible through
+// debugging APIs.
+func PublisherOf[T any](b *Bus, name string) *Publisher[T] {
+	ctx, cancel := context.WithCancel(context.Background())
+	ret := &Publisher[T]{
+		bus:     b,
+		name:    name,
+		stopCtx: ctx,
+		stop:    cancel,
+	}
+	b.addPublisher(ret)
+	return ret
+}
+
+func (p *Publisher[T]) publisherName() string { return p.name }
+
+// Publish publishes event v on the bus.
+func (p *Publisher[T]) Publish(v T) {
+	// Check for just a stopped publisher or bus before trying to
+	// write, so that once closed Publish consistently does nothing.
+	select {
+	case <-p.stopCtx.Done():
+		return
+	case <-p.bus.stop.WaitChan():
+		return
+	default:
+	}
+
+	select {
+	case p.bus.write <- v:
+	case <-p.stopCtx.Done():
+	case <-p.bus.stop.WaitChan():
+	}
+}
+
+// ShouldPublish reports whether anyone is subscribed to events of
+// type T.
+//
+// ShouldPublish can be used to skip expensive event construction if
+// nobody seems to care. Publishers must not assume that someone will
+// definitely receive an event if ShouldPublish returns true.
+func (p *Publisher[T]) ShouldPublish() bool {
+	dests := p.bus.dest(reflect.TypeFor[T]())
+	return len(dests) > 0
+}
+
+// Close closes the publisher, indicating that no further events will
+// be published with it.
+func (p *Publisher[T]) Close() {
+	p.stop()
+	p.bus.deletePublisher(p)
+}

util/eventbus/queue.go

@@ -0,0 +1,83 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package eventbus
+
+import (
+	"slices"
+)
+
+const maxQueuedItems = 16
+
+// queue is an ordered queue of length up to maxQueuedItems.
+type queue struct {
+	vals  []any
+	start int
+}
+
+// canAppend reports whether a value can be appended to q.vals without
+// shifting values around.
+func (q *queue) canAppend() bool {
+	return cap(q.vals) < maxQueuedItems || len(q.vals) < cap(q.vals)
+}
+
+func (q *queue) Full() bool {
+	return q.start == 0 && !q.canAppend()
+}
+
+func (q *queue) Empty() bool {
+	return q.start == len(q.vals)
+}
+
+func (q *queue) Len() int {
+	return len(q.vals) - q.start
+}
+
+// Add adds v to the end of the queue. Blocks until append can be
+// done.
+func (q *queue) Add(v any) {
+	if !q.canAppend() {
+		if q.start == 0 {
+			panic("Add on a full queue")
+		}
+
+		// Slide remaining values back to the start of the array.
+		n := copy(q.vals, q.vals[q.start:])
+		toClear := len(q.vals) - n
+		clear(q.vals[len(q.vals)-toClear:])
+		q.vals = q.vals[:n]
+		q.start = 0
+	}
+
+	q.vals = append(q.vals, v)
+}
+
+// Peek returns the first value in the queue, without removing it from
+// the queue, or nil if the queue is empty.
+func (q *queue) Peek() any {
+	if q.Empty() {
+		return nil
+	}
+
+	return q.vals[q.start]
+}
+
+// Drop discards the first value in the queue, if any.
+func (q *queue) Drop() {
+	if q.Empty() {
+		return
+	}
+
+	q.vals[q.start] = nil
+	q.start++
+	if q.Empty() {
+		// Reset cursor to start of array, it's free to do.
+		q.start = 0
+		q.vals = q.vals[:0]
+	}
+}
+
+// Snapshot returns a copy of the queue's contents.
+func (q *queue) Snapshot() []any {
+	return slices.Clone(q.vals[q.start:])
+}

util/eventbus/subscribe.go

@@ -0,0 +1,170 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package eventbus
+
+import (
+	"fmt"
+	"reflect"
+	"sync"
+)
+
+type dispatchFn func(vals *queue, stop goroutineShutdownWorker, acceptCh func() chan any) bool
+
+// A Queue receives events from a Bus.
+//
+// To receive events through the queue, see [Subscribe]. Subscribers
+// that share the same Queue receive events one at time, in the order
+// they were published.
+type Queue struct {
+	bus  *Bus
+	name string
+
+	write    chan any
+	stop     goroutineShutdownControl
+	snapshot chan chan []any
+
+	outputsMu sync.Mutex
+	outputs   map[reflect.Type]dispatchFn
+}
+
+func newQueue(b *Bus, name string) *Queue {
+	stopCtl, stopWorker := newGoroutineShutdown()
+	ret := &Queue{
+		bus:      b,
+		name:     name,
+		write:    make(chan any),
+		stop:     stopCtl,
+		snapshot: make(chan chan []any),
+		outputs:  map[reflect.Type]dispatchFn{},
+	}
+	b.addQueue(ret)
+	go ret.pump(stopWorker)
+	return ret
+}
+
+func (q *Queue) pump(stop goroutineShutdownWorker) {
+	defer stop.Done()
+	var vals queue
+	acceptCh := func() chan any {
+		if vals.Full() {
+			return nil
+		}
+		return q.write
+	}
+	for {
+		if !vals.Empty() {
+			val := vals.Peek()
+			fn := q.dispatchFn(val)
+			if fn == nil {
+				// Raced with unsubscribe.
+				vals.Drop()
+				continue
+			}
+			if !fn(&vals, stop, acceptCh) {
+				return
+			}
+		} else {
+			// Keep the cases in this select in sync with
+			// Subscriber.dispatch below. The only different should be
+			// that this select doesn't deliver queued values to
+			// anyone, and unconditionally accepts new values.
+			select {
+			case val := <-q.write:
+				vals.Add(val)
+			case <-stop.Stop():
+				return
+			case ch := <-q.snapshot:
+				ch <- vals.Snapshot()
+			}
+		}
+	}
+}
+
+// A Subscriber delivers one type of event from a [Queue].
+type Subscriber[T any] struct {
+	recv *Queue
+	read chan T
+}
+
+func (s *Subscriber[T]) dispatch(vals *queue, stop goroutineShutdownWorker, acceptCh func() chan any) bool {
+	t := vals.Peek().(T)
+	for {
+		// Keep the cases in this select in sync with Queue.pump
+		// above. The only different should be that this select
+		// delivers a value on s.read.
+		select {
+		case s.read <- t:
+			vals.Drop()
+			return true
+		case val := <-acceptCh():
+			vals.Add(val)
+		case <-stop.Stop():
+			return false
+		case ch := <-s.recv.snapshot:
+			ch <- vals.Snapshot()
+		}
+	}
+}
+
+// Events returns a channel on which the subscriber's events are
+// delivered.
+func (s *Subscriber[T]) Events() <-chan T {
+	return s.read
+}
+
+// Close shuts down the Subscriber, indicating the caller no longer
+// wishes to receive these events. After Close, receives on
+// [Subscriber.Chan] block for ever.
+func (s *Subscriber[T]) Close() {
+	t := reflect.TypeFor[T]()
+	s.recv.bus.unsubscribe(t, s.recv)
+	s.recv.deleteDispatchFn(t)
+}
+
+func (q *Queue) dispatchFn(val any) dispatchFn {
+	q.outputsMu.Lock()
+	defer q.outputsMu.Unlock()
+	return q.outputs[reflect.ValueOf(val).Type()]
+}
+
+func (q *Queue) addDispatchFn(t reflect.Type, fn dispatchFn) {
+	q.outputsMu.Lock()
+	defer q.outputsMu.Unlock()
+	if q.outputs[t] != nil {
+		panic(fmt.Errorf("double subscription for event %s", t))
+	}
+	q.outputs[t] = fn
+}
+
+func (q *Queue) deleteDispatchFn(t reflect.Type) {
+	q.outputsMu.Lock()
+	defer q.outputsMu.Unlock()
+	delete(q.outputs, t)
+}
+
+// Done returns a channel that is closed when the Queue is closed.
+func (q *Queue) Done() <-chan struct{} {
+	return q.stop.WaitChan()
+}
+
+// Close closes the queue. All Subscribers attached to the queue are
+// implicitly closed, and any pending events are discarded.
+func (q *Queue) Close() {
+	q.stop.StopAndWait()
+	q.bus.deleteQueue(q)
+}
+
+// Subscribe requests delivery of events of type T through the given
+// Queue. Panics if the queue already has a subscriber for T.
+func Subscribe[T any](r *Queue) Subscriber[T] {
+	t := reflect.TypeFor[T]()
+	ret := Subscriber[T]{
+		recv: r,
+		read: make(chan T),
+	}
+	r.addDispatchFn(t, ret.dispatch)
+	r.bus.subscribe(t, r)
+
+	return ret
+}

util/syspolicy/internal/internal.go

@@ -56,10 +56,10 @@ func EqualJSONForTest(tb TB, j1, j2 jsontext.Value) (s1, s2 string, equal bool)
 		return "", "", true
 	}
 	// Otherwise, format the values for display and return false.
-	if err := j1.Indent("", "\t"); err != nil {
+	if err := j1.Indent(); err != nil {
 		tb.Fatal(err)
 	}
-	if err := j2.Indent("", "\t"); err != nil {
+	if err := j2.Indent(); err != nil {
 		tb.Fatal(err)
 	}
 	return j1.String(), j2.String(), false

util/syspolicy/policy_keys.go

@@ -42,6 +42,12 @@ const (
 	// for auditing purposes. It has no effect when [AlwaysOn] is false.
 	AlwaysOnOverrideWithReason Key = "AlwaysOn.OverrideWithReason"
 
+	// ReconnectAfter is a string value formatted for use with time.ParseDuration()
+	// that defines the duration after which the client should automatically reconnect
+	// to the Tailscale network following a user-initiated disconnect.
+	// An empty string or a zero duration disables automatic reconnection.
+	ReconnectAfter Key = "ReconnectAfter"
+
 	// ExitNodeID is the exit node's node id. default ""; if blank, no exit node is forced.
 	// Exit node ID takes precedence over exit node IP.
 	// To find the node ID, go to /api.md#device.
@@ -176,6 +182,7 @@ var implicitDefinitions = []*setting.Definition{
 	setting.NewDefinition(LogTarget, setting.DeviceSetting, setting.StringValue),
 	setting.NewDefinition(MachineCertificateSubject, setting.DeviceSetting, setting.StringValue),
 	setting.NewDefinition(PostureChecking, setting.DeviceSetting, setting.PreferenceOptionValue),
+	setting.NewDefinition(ReconnectAfter, setting.DeviceSetting, setting.DurationValue),
 	setting.NewDefinition(Tailnet, setting.DeviceSetting, setting.StringValue),
 
 	// User policy settings (can be configured on a user- or device-basis):

util/syspolicy/setting/origin.go

@@ -50,22 +50,27 @@ func (s Origin) String() string {
 	return s.Scope().String()
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (s Origin) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return jsonv2.MarshalEncode(out, &s.data, opts)
+var (
+	_ jsonv2.MarshalerTo     = (*Origin)(nil)
+	_ jsonv2.UnmarshalerFrom = (*Origin)(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (s Origin) MarshalJSONTo(out *jsontext.Encoder) error {
+	return jsonv2.MarshalEncode(out, &s.data)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (s *Origin) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
-	return jsonv2.UnmarshalDecode(in, &s.data, opts)
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (s *Origin) UnmarshalJSONFrom(in *jsontext.Decoder) error {
+	return jsonv2.UnmarshalDecode(in, &s.data)
 }
 
 // MarshalJSON implements [json.Marshaler].
 func (s Origin) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(s) // uses MarshalJSONV2
+	return jsonv2.Marshal(s) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (s *Origin) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, s) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, s) // uses UnmarshalJSONFrom
 }

util/syspolicy/setting/raw_item.go

@@ -75,31 +75,36 @@ func (i RawItem) String() string {
 	return fmt.Sprintf("%v%s", i.data.Value.Value, suffix)
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (i RawItem) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return jsonv2.MarshalEncode(out, &i.data, opts)
+var (
+	_ jsonv2.MarshalerTo     = (*RawItem)(nil)
+	_ jsonv2.UnmarshalerFrom = (*RawItem)(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (i RawItem) MarshalJSONTo(out *jsontext.Encoder) error {
+	return jsonv2.MarshalEncode(out, &i.data)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (i *RawItem) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
-	return jsonv2.UnmarshalDecode(in, &i.data, opts)
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (i *RawItem) UnmarshalJSONFrom(in *jsontext.Decoder) error {
+	return jsonv2.UnmarshalDecode(in, &i.data)
 }
 
 // MarshalJSON implements [json.Marshaler].
 func (i RawItem) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(i) // uses MarshalJSONV2
+	return jsonv2.Marshal(i) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (i *RawItem) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, i) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, i) // uses UnmarshalJSONFrom
 }
 
 // RawValue represents a raw policy setting value read from a policy store.
 // It is JSON-marshallable and facilitates unmarshalling of JSON values
 // into corresponding policy setting types, with special handling for JSON numbers
 // (unmarshalled as float64) and JSON string arrays (unmarshalled as []string).
-// See also [RawValue.UnmarshalJSONV2].
+// See also [RawValue.UnmarshalJSONFrom].
 type RawValue struct {
 	opt.Value[any]
 }
@@ -114,16 +119,21 @@ func RawValueOf[T RawValueType](v T) RawValue {
 	return RawValue{opt.ValueOf[any](v)}
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (v RawValue) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return jsonv2.MarshalEncode(out, v.Value, opts)
+var (
+	_ jsonv2.MarshalerTo     = (*RawValue)(nil)
+	_ jsonv2.UnmarshalerFrom = (*RawValue)(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (v RawValue) MarshalJSONTo(out *jsontext.Encoder) error {
+	return jsonv2.MarshalEncode(out, v.Value)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2] by attempting to unmarshal
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom] by attempting to unmarshal
 // a JSON value as one of the supported policy setting value types (bool, string, uint64, or []string),
 // based on the JSON value type. It fails if the JSON value is an object, if it's a JSON number that
 // cannot be represented as a uint64, or if a JSON array contains anything other than strings.
-func (v *RawValue) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+func (v *RawValue) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	var valPtr any
 	switch k := in.PeekKind(); k {
 	case 't', 'f':
@@ -139,7 +149,7 @@ func (v *RawValue) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) er
 	default:
 		panic("unreachable")
 	}
-	if err := jsonv2.UnmarshalDecode(in, valPtr, opts); err != nil {
+	if err := jsonv2.UnmarshalDecode(in, valPtr); err != nil {
 		v.Value.Clear()
 		return err
 	}
@@ -150,12 +160,12 @@ func (v *RawValue) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) er
 
 // MarshalJSON implements [json.Marshaler].
 func (v RawValue) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(v) // uses MarshalJSONV2
+	return jsonv2.Marshal(v) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (v *RawValue) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, v) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, v) // uses UnmarshalJSONFrom
 }
 
 // RawValues is a map of keyed setting values that can be read from a JSON.

util/syspolicy/setting/snapshot.go

@@ -147,23 +147,28 @@ type snapshotJSON struct {
 	Settings map[Key]RawItem `json:",omitempty"`
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (s *Snapshot) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
+var (
+	_ jsonv2.MarshalerTo     = (*Snapshot)(nil)
+	_ jsonv2.UnmarshalerFrom = (*Snapshot)(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (s *Snapshot) MarshalJSONTo(out *jsontext.Encoder) error {
 	data := &snapshotJSON{}
 	if s != nil {
 		data.Summary = s.summary
 		data.Settings = s.m
 	}
-	return jsonv2.MarshalEncode(out, data, opts)
+	return jsonv2.MarshalEncode(out, data)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (s *Snapshot) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (s *Snapshot) UnmarshalJSONFrom(in *jsontext.Decoder) error {
 	if s == nil {
 		return errors.New("s must not be nil")
 	}
 	data := &snapshotJSON{}
-	if err := jsonv2.UnmarshalDecode(in, data, opts); err != nil {
+	if err := jsonv2.UnmarshalDecode(in, data); err != nil {
 		return err
 	}
 	*s = Snapshot{m: data.Settings, sig: deephash.Hash(&data.Settings), summary: data.Summary}
@@ -172,12 +177,12 @@ func (s *Snapshot) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) er
 
 // MarshalJSON implements [json.Marshaler].
 func (s *Snapshot) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(s) // uses MarshalJSONV2
+	return jsonv2.Marshal(s) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (s *Snapshot) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, s) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, s) // uses UnmarshalJSONFrom
 }
 
 // MergeSnapshots returns a [Snapshot] that contains all [RawItem]s

util/syspolicy/setting/summary.go

@@ -54,24 +54,29 @@ func (s Summary) String() string {
 	return s.data.Scope.String()
 }
 
-// MarshalJSONV2 implements [jsonv2.MarshalerV2].
-func (s Summary) MarshalJSONV2(out *jsontext.Encoder, opts jsonv2.Options) error {
-	return jsonv2.MarshalEncode(out, &s.data, opts)
+var (
+	_ jsonv2.MarshalerTo     = (*Summary)(nil)
+	_ jsonv2.UnmarshalerFrom = (*Summary)(nil)
+)
+
+// MarshalJSONTo implements [jsonv2.MarshalerTo].
+func (s Summary) MarshalJSONTo(out *jsontext.Encoder) error {
+	return jsonv2.MarshalEncode(out, &s.data)
 }
 
-// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
-func (s *Summary) UnmarshalJSONV2(in *jsontext.Decoder, opts jsonv2.Options) error {
-	return jsonv2.UnmarshalDecode(in, &s.data, opts)
+// UnmarshalJSONFrom implements [jsonv2.UnmarshalerFrom].
+func (s *Summary) UnmarshalJSONFrom(in *jsontext.Decoder) error {
+	return jsonv2.UnmarshalDecode(in, &s.data)
 }
 
 // MarshalJSON implements [json.Marshaler].
 func (s Summary) MarshalJSON() ([]byte, error) {
-	return jsonv2.Marshal(s) // uses MarshalJSONV2
+	return jsonv2.Marshal(s) // uses MarshalJSONTo
 }
 
 // UnmarshalJSON implements [json.Unmarshaler].
 func (s *Summary) UnmarshalJSON(b []byte) error {
-	return jsonv2.Unmarshal(b, s) // uses UnmarshalJSONV2
+	return jsonv2.Unmarshal(b, s) // uses UnmarshalJSONFrom
 }
 
 // SummaryOption is an option that configures [Summary]