cmd/containerboot/egressservices.go

@@ -27,7 +27,7 @@ import (
 	"tailscale.com/kube/egressservices"
 	"tailscale.com/kube/kubeclient"
 	"tailscale.com/kube/kubetypes"
-	"tailscale.com/types/netmap"
+	"tailscale.com/types/views"
 	"tailscale.com/util/httpm"
 	"tailscale.com/util/linuxfw"
 	"tailscale.com/util/mak"
@@ -55,7 +55,7 @@ type egressProxy struct {
 
 	tsClient *local.Client // never nil
 
-	netmapChan chan *netmap.NetworkMap // chan to receive netmap updates on
+	netmapChan chan netmapState // chan to receive netmap state updates on
 
 	podIPv4 string // never empty string, currently only IPv4 is supported
 
@@ -87,7 +87,7 @@ type httpClient interface {
 // - the mounted egress config has changed
 // - the proxy's tailnet IP addresses have changed
 // - tailnet IPs have changed for any backend targets specified by tailnet FQDN
-func (ep *egressProxy) run(ctx context.Context, nm *netmap.NetworkMap, opts egressProxyRunOpts) error {
+func (ep *egressProxy) run(ctx context.Context, nm netmapState, opts egressProxyRunOpts) error {
 	ep.configure(opts)
 	var tickChan <-chan time.Time
 	var eventChan <-chan fsnotify.Event
@@ -136,7 +136,7 @@ type egressProxyRunOpts struct {
 	kc           kubeclient.Client
 	tsClient     *local.Client
 	stateSecret  string
-	netmapChan   chan *netmap.NetworkMap
+	netmapChan   chan netmapState
 	podIPv4      string
 	tailnetAddrs []netip.Prefix
 }
@@ -165,7 +165,7 @@ func (ep *egressProxy) configure(opts egressProxyRunOpts) {
 // any firewall rules need to be updated. Currently using status in state Secret as a reference for what is the current
 // firewall configuration is good enough because - the status is keyed by the Pod IP - we crash the Pod on errors such
 // as failed firewall update
-func (ep *egressProxy) sync(ctx context.Context, nm *netmap.NetworkMap) error {
+func (ep *egressProxy) sync(ctx context.Context, nm netmapState) error {
 	cfgs, err := ep.getConfigs()
 	if err != nil {
 		return fmt.Errorf("error retrieving egress service configs: %w", err)
@@ -186,16 +186,15 @@ func (ep *egressProxy) sync(ctx context.Context, nm *netmap.NetworkMap) error {
 	return nil
 }
 
-// addrsHaveChanged returns true if the provided netmap update contains tailnet address change for this proxy node.
-// Netmap must not be nil.
-func (ep *egressProxy) addrsHaveChanged(nm *netmap.NetworkMap) bool {
-	return !reflect.DeepEqual(ep.tailnetAddrs, nm.SelfNode.Addresses())
+// addrsHaveChanged returns true if the provided netmap state contains tailnet address change for this proxy node.
+func (ep *egressProxy) addrsHaveChanged(nm netmapState) bool {
+	return !views.SliceEqual(views.SliceOf(ep.tailnetAddrs), nm.self.Addresses())
 }
 
 // syncEgressConfigs adds and deletes firewall rules to match the desired
 // configuration. It uses the provided status to determine what is currently
 // applied and updates the status after a successful sync.
-func (ep *egressProxy) syncEgressConfigs(cfgs egressservices.Configs, status *egressservices.Status, nm *netmap.NetworkMap) (*egressservices.Status, error) {
+func (ep *egressProxy) syncEgressConfigs(cfgs egressservices.Configs, status *egressservices.Status, nm netmapState) (*egressservices.Status, error) {
 	if !(wantsServicesConfigured(cfgs) || hasServicesConfigured(status)) {
 		return nil, nil
 	}
@@ -234,7 +233,7 @@ func (ep *egressProxy) syncEgressConfigs(cfgs egressservices.Configs, status *eg
 			// family.
 			for _, t := range tailnetTargetIPs {
 				var local netip.Addr
-				for _, pfx := range nm.SelfNode.Addresses().All() {
+				for _, pfx := range nm.self.Addresses().All() {
 					if !pfx.IsSingleIP() {
 						continue
 					}
@@ -424,7 +423,7 @@ func (ep *egressProxy) getStatus(ctx context.Context) (*egressservices.Status, e
 
 // setStatus writes egress proxy's currently configured firewall to the state
 // Secret and updates proxy's tailnet addresses.
-func (ep *egressProxy) setStatus(ctx context.Context, status *egressservices.Status, nm *netmap.NetworkMap) error {
+func (ep *egressProxy) setStatus(ctx context.Context, status *egressservices.Status, nm netmapState) error {
 	// Pod IP is used to determine if a stored status applies to THIS proxy Pod.
 	if status == nil {
 		status = &egressservices.Status{}
@@ -447,7 +446,7 @@ func (ep *egressProxy) setStatus(ctx context.Context, status *egressservices.Sta
 	if err := ep.kc.JSONPatchResource(ctx, ep.stateSecret, kubeclient.TypeSecrets, []kubeclient.JSONPatch{patch}); err != nil {
 		return fmt.Errorf("error patching state Secret: %w", err)
 	}
-	ep.tailnetAddrs = nm.SelfNode.Addresses().AsSlice()
+	ep.tailnetAddrs = nm.self.Addresses().AsSlice()
 	return nil
 }
 
@@ -457,7 +456,7 @@ func (ep *egressProxy) setStatus(ctx context.Context, status *egressservices.Sta
 // FQDN, resolve the FQDN and return the resolved IPs. It checks if the
 // netfilter runner supports IPv6 NAT and skips any IPv6 addresses if it
 // doesn't.
-func (ep *egressProxy) tailnetTargetIPsForSvc(svc egressservices.Config, nm *netmap.NetworkMap) (addrs []netip.Addr, err error) {
+func (ep *egressProxy) tailnetTargetIPsForSvc(svc egressservices.Config, nm netmapState) (addrs []netip.Addr, err error) {
 	if svc.TailnetTarget.IP != "" {
 		addr, err := netip.ParseAddr(svc.TailnetTarget.IP)
 		if err != nil {
@@ -473,8 +472,8 @@ func (ep *egressProxy) tailnetTargetIPsForSvc(svc egressservices.Config, nm *net
 	if svc.TailnetTarget.FQDN == "" {
 		return nil, errors.New("unexpected egress service config- neither tailnet target IP nor FQDN is set")
 	}
-	if nm == nil {
-		log.Printf("netmap is not available, unable to determine backend addresses for %s", svc.TailnetTarget.FQDN)
+	if !nm.self.Valid() {
+		log.Printf("netmap state is not available, unable to determine backend addresses for %s", svc.TailnetTarget.FQDN)
 		return addrs, nil
 	}
 	egressAddrs, err := resolveTailnetFQDN(nm, svc.TailnetTarget.FQDN)
@@ -501,26 +500,26 @@ func (ep *egressProxy) tailnetTargetIPsForSvc(svc egressservices.Config, nm *net
 	return addrs, nil
 }
 
-// shouldResync parses netmap update and returns true if the update contains
+// shouldResync parses netmap state update and returns true if the update contains
 // changes for which the egress proxy's firewall should be reconfigured.
-func (ep *egressProxy) shouldResync(nm *netmap.NetworkMap) bool {
-	if nm == nil {
+func (ep *egressProxy) shouldResync(nm netmapState) bool {
+	if !nm.self.Valid() {
 		return false
 	}
 
 	// If proxy's tailnet addresses have changed, resync.
-	if !reflect.DeepEqual(nm.SelfNode.Addresses().AsSlice(), ep.tailnetAddrs) {
+	if !views.SliceEqual(nm.self.Addresses(), views.SliceOf(ep.tailnetAddrs)) {
 		log.Printf("node addresses have changed, trigger egress config resync")
-		ep.tailnetAddrs = nm.SelfNode.Addresses().AsSlice()
+		ep.tailnetAddrs = nm.self.Addresses().AsSlice()
 		return true
 	}
 
 	// If the IPs for any of the egress services configured via FQDN have
 	// changed, resync.
 	for fqdn, ips := range ep.targetFQDNs {
-		for _, nn := range nm.Peers {
+		for nn := range nm.peers() {
 			if equalFQDNs(nn.Name(), fqdn) {
-				if !reflect.DeepEqual(ips, nn.Addresses().AsSlice()) {
+				if !views.SliceEqual(views.SliceOf(ips), nn.Addresses()) {
 					log.Printf("backend addresses for egress target %q have changed old IPs %v, new IPs %v trigger egress config resync", nn.Name(), ips, nn.Addresses().AsSlice())
 					return true
 				}

cmd/containerboot/main.go

@@ -120,6 +120,7 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
+	"iter"
 	"log"
 	"math"
 	"net"
@@ -136,11 +137,12 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/benbjohnson/immutable"
 	"golang.org/x/sys/unix"
 
-	"tailscale.com/client/local"
 	"tailscale.com/health"
 	"tailscale.com/ipn"
+	"tailscale.com/ipn/ipnstate"
 	kubeutils "tailscale.com/k8s-operator"
 	"tailscale.com/kube/authkey"
 	healthz "tailscale.com/kube/health"
@@ -151,7 +153,7 @@ import (
 	"tailscale.com/net/tsaddr"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/logger"
-	"tailscale.com/types/netmap"
+	"tailscale.com/types/views"
 	"tailscale.com/util/deephash"
 	"tailscale.com/util/dnsname"
 	"tailscale.com/util/linuxfw"
@@ -168,6 +170,137 @@ func getAutoAdvertiseBool() bool {
 	return defaultBool("TS_EXPERIMENTAL_SERVICE_AUTO_ADVERTISEMENT", true)
 }
 
+const containerbootWatchMask = ipn.NotifyInitialStatus |
+	ipn.NotifyPeerChanges |
+	ipn.NotifyNoNetMap
+
+func notifyState(n ipn.Notify) (_ ipn.State, ok bool) {
+	if n.State != nil {
+		return *n.State, true
+	}
+	if n.InitialStatus != nil && n.InitialStatus.BackendState != "" {
+		if state, ok := ipn.StateFromString(n.InitialStatus.BackendState); ok {
+			return state, true
+		}
+	}
+	return ipn.NoState, false
+}
+
+var netmapStatePeerIDHasher = immutable.NewHasher(tailcfg.NodeID(0))
+
+type netmapState struct {
+	self            tailcfg.NodeView
+	peersByID       *immutable.Map[tailcfg.NodeID, tailcfg.NodeView]
+	peersByName     *immutable.Map[string, tailcfg.NodeView] // keyed by tailcfg.Node.Name when NodeID is unavailable
+	certDomains     views.Slice[string]
+	dnsExtraRecords views.Slice[tailcfg.DNSRecord]
+}
+
+func (s netmapState) updateFromNotify(n ipn.Notify) netmapState {
+	if n.InitialStatus != nil {
+		s = s.updateFromStatus(n.InitialStatus)
+	}
+	if n.SelfChange != nil {
+		s.self = n.SelfChange.View()
+	}
+	for _, p := range n.PeersChanged {
+		s = s.upsertPeer(p.View())
+	}
+	for _, id := range n.PeersRemoved {
+		if s.peersByID != nil {
+			s.peersByID = s.peersByID.Delete(id)
+		}
+	}
+	return s
+}
+
+func (s netmapState) updateFromStatus(st *ipnstate.Status) netmapState {
+	s.certDomains = views.SliceOf(st.CertDomains)
+	s.dnsExtraRecords = views.SliceOf(st.ExtraRecords)
+	if st.Self != nil {
+		s.self = nodeFromPeerStatus(st.Self).View()
+	}
+	if len(st.Peer) != 0 {
+		s.peersByID = nil
+		s.peersByName = nil
+		for _, ps := range st.Peer {
+			s = s.upsertPeer(nodeFromPeerStatus(ps).View())
+		}
+	}
+	return s
+}
+
+func (s netmapState) upsertPeer(n tailcfg.NodeView) netmapState {
+	if !n.Valid() {
+		return s
+	}
+	if s.peersByID == nil {
+		s.peersByID = immutable.NewMap[tailcfg.NodeID, tailcfg.NodeView](netmapStatePeerIDHasher)
+	}
+	if s.peersByName == nil {
+		s.peersByName = immutable.NewMap[string, tailcfg.NodeView](nil)
+	}
+	if n.ID() != 0 {
+		s.peersByID = s.peersByID.Set(n.ID(), n)
+		if name := n.Name(); name != "" {
+			s.peersByName = s.peersByName.Delete(name)
+		}
+		return s
+	}
+	if n.Name() != "" {
+		s.peersByName = s.peersByName.Set(n.Name(), n)
+	}
+	return s
+}
+
+func nodeFromPeerStatus(ps *ipnstate.PeerStatus) *tailcfg.Node {
+	if ps == nil {
+		return nil
+	}
+	n := &tailcfg.Node{
+		ID:       ps.NodeID,
+		StableID: ps.ID,
+		Name:     ps.DNSName,
+		Key:      ps.PublicKey,
+	}
+	for _, ip := range ps.TailscaleIPs {
+		n.Addresses = append(n.Addresses, netip.PrefixFrom(ip, ip.BitLen()))
+	}
+	if ps.AllowedIPs != nil {
+		n.AllowedIPs = ps.AllowedIPs.AsSlice()
+	}
+	return n
+}
+
+func (s netmapState) peers() iter.Seq[tailcfg.NodeView] {
+	return func(yield func(tailcfg.NodeView) bool) {
+		if s.peersByID != nil {
+			it := s.peersByID.Iterator()
+			for {
+				_, p, ok := it.Next()
+				if !ok {
+					break
+				}
+				if !yield(p) {
+					return
+				}
+			}
+		}
+		if s.peersByName != nil {
+			it := s.peersByName.Iterator()
+			for {
+				_, p, ok := it.Next()
+				if !ok {
+					break
+				}
+				if !yield(p) {
+					return
+				}
+			}
+		}
+	}
+}
+
 func main() {
 	if err := run(); err != nil && !errors.Is(err, context.Canceled) {
 		log.Fatal(err)
@@ -308,7 +441,7 @@ func run() error {
 		}
 	}
 
-	w, err := client.WatchIPNBus(bootCtx, ipn.NotifyInitialNetMap|ipn.NotifyInitialPrefs|ipn.NotifyInitialState|ipn.NotifyInitialHealthState|ipn.NotifyRateLimit)
+	w, err := client.WatchIPNBus(bootCtx, containerbootWatchMask|ipn.NotifyInitialPrefs|ipn.NotifyInitialHealthState)
 	if err != nil {
 		return fmt.Errorf("failed to watch tailscaled for updates: %w", err)
 	}
@@ -348,7 +481,7 @@ func run() error {
 		if err := tailscaleUp(bootCtx, cfg); err != nil {
 			return fmt.Errorf("failed to auth tailscale: %w", err)
 		}
-		w, err = client.WatchIPNBus(bootCtx, ipn.NotifyInitialNetMap|ipn.NotifyInitialState|ipn.NotifyRateLimit)
+		w, err = client.WatchIPNBus(bootCtx, containerbootWatchMask)
 		if err != nil {
 			return fmt.Errorf("rewatching tailscaled for updates after auth: %w", err)
 		}
@@ -368,8 +501,8 @@ authLoop:
 			return fmt.Errorf("failed to read from tailscaled: %w", err)
 		}
 
-		if n.State != nil {
-			switch *n.State {
+		if state, ok := notifyState(n); ok {
+			switch state {
 			case ipn.NeedsLogin:
 				if isOneStepConfig(cfg) {
 					// This could happen if this is the first time tailscaled was run for this
@@ -405,7 +538,7 @@ authLoop:
 				// deadline to continue monitoring for changes.
 				break authLoop
 			default:
-				log.Printf("tailscaled in state %q, waiting", *n.State)
+				log.Printf("tailscaled in state %q, waiting", state)
 			}
 		}
 
@@ -460,7 +593,7 @@ authLoop:
 		}
 	}
 
-	w, err = client.WatchIPNBus(ctx, ipn.NotifyInitialNetMap|ipn.NotifyInitialState|ipn.NotifyRateLimit)
+	w, err = client.WatchIPNBus(ctx, containerbootWatchMask)
 	if err != nil {
 		return fmt.Errorf("rewatching tailscaled for updates after auth: %w", err)
 	}
@@ -539,7 +672,7 @@ authLoop:
 		failedResolveAttempts++
 	}
 
-	var egressSvcsNotify chan *netmap.NetworkMap
+	var egressSvcsNotify chan netmapState
 	notifyChan := make(chan ipn.Notify)
 	errChan := make(chan error)
 	go func() {
@@ -553,12 +686,7 @@ authLoop:
 			}
 		}
 	}()
-	// Peer set changes (Add/Remove) no longer ride on the IPN bus; poll
-	// periodically so egress FQDN resolution and peer-aware work picks
-	// them up. SelfChange covers prompt self changes.
-	const peerPollInterval = 15 * time.Second
-	peerPoll := time.NewTicker(peerPollInterval)
-	defer peerPoll.Stop()
+	var nmState netmapState
 	var wg sync.WaitGroup
 
 runLoop:
@@ -576,19 +704,17 @@ runLoop:
 			return fmt.Errorf("failed to read from tailscaled: %w", err)
 		case err := <-cfgWatchErrChan:
 			return fmt.Errorf("failed to watch tailscaled config: %w", err)
-		case <-peerPoll.C:
-			processNetmap = true
 		case n := <-notifyChan:
-			// TODO: (ChaosInTheCRD) Add node removed check when supported by ipn
-			if n.State != nil && *n.State != ipn.Running {
+			nmState = nmState.updateFromNotify(n)
+			if state, ok := notifyState(n); ok && state != ipn.Running {
 				// Something's gone wrong and we've left the authenticated state.
 				// Our container image never recovered gracefully from this, and the
 				// control flow required to make it work now is hard. So, just crash
 				// the container and rely on the container runtime to restart us,
 				// whereupon we'll go through initial auth again.
-				return fmt.Errorf("tailscaled left running state (now in state %q), exiting", *n.State)
+				return fmt.Errorf("tailscaled left running state (now in state %q), exiting", state)
 			}
-			if n.SelfChange != nil {
+			if n.InitialStatus != nil || n.SelfChange != nil || len(n.PeersChanged) != 0 || len(n.PeersRemoved) != 0 || len(n.PeerChangedPatch) != 0 {
 				processNetmap = true
 			}
 		case <-tc:
@@ -618,13 +744,12 @@ runLoop:
 		if !processNetmap {
 			continue
 		}
-		nm, err := fetchNetMap(ctx, client)
-		if err != nil {
-			log.Printf("error fetching netmap: %v", err)
+		self := nmState.self
+		if !self.Valid() {
 			continue
 		}
-		if nm != nil {
-			addrs = nm.SelfNode.Addresses().AsSlice()
+		{
+			addrs = self.Addresses().AsSlice()
 			newCurrentIPs := deephash.Hash(&addrs)
 			ipsHaveChanged := newCurrentIPs != currentIPs
 
@@ -636,14 +761,14 @@ runLoop:
 			// Kubernetes Secret to clean up tailnet nodes
 			// for proxies whose route setup continuously
 			// fails.
-			deviceID := nm.SelfNode.StableID()
+			deviceID := self.StableID()
 			if hasKubeStateStore(cfg) && deephash.Update(&currentDeviceID, &deviceID) {
-				if err := kc.storeDeviceID(ctx, nm.SelfNode.StableID()); err != nil {
+				if err := kc.storeDeviceID(ctx, deviceID); err != nil {
 					return fmt.Errorf("storing device ID in Kubernetes Secret: %w", err)
 				}
 			}
 			if cfg.TailnetTargetFQDN != "" {
-				egressAddrs, err := resolveTailnetFQDN(nm, cfg.TailnetTargetFQDN)
+				egressAddrs, err := resolveTailnetFQDN(nmState, cfg.TailnetTargetFQDN)
 				if err != nil {
 					log.Print(err.Error())
 					break
@@ -699,7 +824,10 @@ runLoop:
 				backendAddrs = newBackendAddrs
 			}
 			if cfg.ServeConfigPath != "" {
-				cd := certDomainFromNetmap(nm)
+				var cd string
+				if nmState.certDomains.Len() != 0 {
+					cd = nmState.certDomains.At(0)
+				}
 				if cd == "" {
 					cd = kubetypes.ValueNoHTTPS
 				}
@@ -742,9 +870,9 @@ runLoop:
 			// set up ensures that the operator does not
 			// advertize endpoints of broken proxies.
 			// TODO (irbekrm): instead of using the IP and FQDN, have some other mechanism for the proxy signal that it is 'Ready'.
-			deviceEndpoints := []any{nm.SelfNode.Name(), nm.SelfNode.Addresses()}
+			deviceEndpoints := []any{self.Name(), self.Addresses()}
 			if hasKubeStateStore(cfg) && deephash.Update(&currentDeviceEndpoints, &deviceEndpoints) {
-				if err := kc.storeDeviceEndpoints(ctx, nm.SelfNode.Name(), nm.SelfNode.Addresses().AsSlice()); err != nil {
+				if err := kc.storeDeviceEndpoints(ctx, self.Name(), addrs); err != nil {
 					return fmt.Errorf("storing device IPs and FQDN in Kubernetes Secret: %w", err)
 				}
 			}
@@ -773,7 +901,7 @@ runLoop:
 			}
 
 			if egressSvcsNotify != nil {
-				egressSvcsNotify <- nm
+				egressSvcsNotify <- nmState
 			}
 		}
 		if !startupTasksDone {
@@ -795,7 +923,7 @@ runLoop:
 				// will crash this node.
 				if cfg.EgressProxiesCfgPath != "" {
 					log.Printf("configuring egress proxy using configuration file at %s", cfg.EgressProxiesCfgPath)
-					egressSvcsNotify = make(chan *netmap.NetworkMap)
+					egressSvcsNotify = make(chan netmapState)
 					opts := egressProxyRunOpts{
 						cfgPath:      cfg.EgressProxiesCfgPath,
 						nfr:          nfr,
@@ -807,7 +935,7 @@ runLoop:
 						tailnetAddrs: addrs,
 					}
 					go func() {
-						if err := ep.run(ctx, nm, opts); err != nil {
+						if err := ep.run(ctx, nmState, opts); err != nil {
 							egressSvcsErrorChan <- err
 						}
 					}()
@@ -987,30 +1115,26 @@ func runHTTPServer(mux *http.ServeMux, addr string) (close func() error) {
 	}
 }
 
-// fetchNetMap fetches the current netmap from tailscaled via the
-// "current-netmap" localapi debug action. The debug action's payload
-// shape is intentionally not part of any stable API; containerboot
-// reads its own internal-package types out of it. New external consumers
-// should not rely on this — see [local.Client.Status] and friends.
-func fetchNetMap(ctx context.Context, lc *local.Client) (*netmap.NetworkMap, error) {
-	return local.GetDebugResultJSON[*netmap.NetworkMap](ctx, lc, "current-netmap")
-}
-
 // resolveTailnetFQDN resolves a tailnet FQDN to a list of IP prefixes, which
 // can be either a peer device, a Tailscale Service, or a 4via6 synthesized
 // DNS name (e.g. "10-1-0-5-via-7.tailnet.ts.net").
-func resolveTailnetFQDN(nm *netmap.NetworkMap, fqdn string) ([]netip.Prefix, error) {
+func resolveTailnetFQDN(nm netmapState, fqdn string) ([]netip.Prefix, error) {
 	dnsFQDN, err := dnsname.ToFQDN(fqdn)
 	if err != nil {
 		return nil, fmt.Errorf("error parsing %q as FQDN: %w", fqdn, err)
 	}
 
 	// Check all peer devices first.
-	for _, p := range nm.Peers {
+	var ret []netip.Prefix
+	for p := range nm.peers() {
 		if strings.EqualFold(p.Name(), dnsFQDN.WithTrailingDot()) {
-			return p.Addresses().AsSlice(), nil
+			ret = p.Addresses().AsSlice()
+			break
 		}
 	}
+	if ret != nil {
+		return ret, nil
+	}
 
 	// If not found yet, check for a matching Tailscale Service.
 	if svcIPs := serviceIPsFromNetMap(nm, dnsFQDN); len(svcIPs) != 0 {
@@ -1020,7 +1144,7 @@ func resolveTailnetFQDN(nm *netmap.NetworkMap, fqdn string) ([]netip.Prefix, err
 	// If not found yet, check for a matching 4via6 DNS name.
 	if addr, ok := resolveViaDomain(dnsFQDN); ok {
 		prefix := netip.PrefixFrom(addr, addr.BitLen())
-		for _, nn := range nm.Peers {
+		for nn := range nm.peers() {
 			for _, allowedIP := range nn.AllowedIPs().All() {
 				if allowedIP.Contains(addr) {
 					return []netip.Prefix{prefix}, nil
@@ -1036,9 +1160,9 @@ func resolveTailnetFQDN(nm *netmap.NetworkMap, fqdn string) ([]netip.Prefix, err
 // serviceIPsFromNetMap returns all IPs of a Tailscale Service if its FQDN is
 // found in the netmap. Note that Tailscale Services are not a first-class
 // object in the netmap, so we guess based on DNS ExtraRecords and AllowedIPs.
-func serviceIPsFromNetMap(nm *netmap.NetworkMap, fqdn dnsname.FQDN) []netip.Prefix {
+func serviceIPsFromNetMap(nm netmapState, fqdn dnsname.FQDN) []netip.Prefix {
 	var extraRecords []tailcfg.DNSRecord
-	for _, rec := range nm.DNS.ExtraRecords {
+	for _, rec := range nm.dnsExtraRecords.All() {
 		recFQDN, err := dnsname.ToFQDN(rec.Name)
 		if err != nil {
 			continue
@@ -1060,7 +1184,7 @@ func serviceIPsFromNetMap(nm *netmap.NetworkMap, fqdn dnsname.FQDN) []netip.Pref
 			continue
 		}
 		ipPrefix := netip.PrefixFrom(ip, ip.BitLen())
-		for _, ps := range nm.Peers {
+		for ps := range nm.peers() {
 			for _, allowedIP := range ps.AllowedIPs().All() {
 				if allowedIP == ipPrefix {
 					prefixes = append(prefixes, ipPrefix)

cmd/containerboot/main_test.go

@@ -35,12 +35,13 @@ import (
 	"tailscale.com/cmd/testwrapper/flakytest"
 	"tailscale.com/health"
 	"tailscale.com/ipn"
+	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/kube/egressservices"
 	"tailscale.com/kube/kubeclient"
 	"tailscale.com/kube/kubetypes"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tstest"
-	"tailscale.com/types/netmap"
+	"tailscale.com/types/key"
 )
 
 const configFileAuthKey = "some-auth-key"
@@ -52,6 +53,7 @@ func TestContainerBoot(t *testing.T) {
 		t.Fatalf("Building containerboot: %v", err)
 	}
 	egressStatus := egressSvcStatus("foo", "foo.tailnetxyz.ts.net", "100.64.0.2")
+	egressStatusUpdated := egressSvcStatus("foo", "foo.tailnetxyz.ts.net", "100.64.0.3")
 
 	metricsURL := func(port int) string {
 		return fmt.Sprintf("http://127.0.0.1:%d/metrics", port)
@@ -71,12 +73,6 @@ func TestContainerBoot(t *testing.T) {
 		// Waits below to be true before proceeding to the next phase.
 		Notify *ipn.Notify
 
-		// If non-nil, install this NetMap on the fake LocalAPI before
-		// sending Notify. This is the replacement for the old
-		// Notify.NetMap field; reactive consumers fetch the current
-		// netmap via /localapi/v0/netmap on their own.
-		NetMap *netmap.NetworkMap
-
 		// WantCmds is the commands that containerboot should run in this phase.
 		WantCmds []string
 
@@ -392,19 +388,12 @@ func TestContainerBoot(t *testing.T) {
 								Name:      "test-node.test.ts.net.",
 								Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
 							},
-						},
-						NetMap: &netmap.NetworkMap{
-							SelfNode: (&tailcfg.Node{
-								StableID:  tailcfg.StableNodeID("myID"),
-								Name:      "test-node.test.ts.net.",
-								Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
-							}).View(),
-							Peers: []tailcfg.NodeView{
-								(&tailcfg.Node{
+							PeersChanged: []*tailcfg.Node{
+								{
 									StableID:  tailcfg.StableNodeID("ipv6ID"),
 									Name:      "ipv6-node.test.ts.net.",
 									Addresses: []netip.Prefix{netip.MustParsePrefix("::1/128")},
-								}).View(),
+								},
 							},
 						},
 						WantLog:      "no forwarding rules for egress addresses [::1/128], host supports IPv6: false",
@@ -646,13 +635,6 @@ func TestContainerBoot(t *testing.T) {
 								Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
 							},
 						},
-						NetMap: &netmap.NetworkMap{
-							SelfNode: (&tailcfg.Node{
-								StableID:  tailcfg.StableNodeID("newID"),
-								Name:      "new-name.test.ts.net.",
-								Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
-							}).View(),
-						},
 						WantKubeSecret: map[string]string{
 							"authkey":           "tskey-key",
 							"device_fqdn":       "new-name.test.ts.net.",
@@ -1114,19 +1096,12 @@ func TestContainerBoot(t *testing.T) {
 								Name:      "test-node.test.ts.net.",
 								Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
 							},
-						},
-						NetMap: &netmap.NetworkMap{
-							SelfNode: (&tailcfg.Node{
-								StableID:  tailcfg.StableNodeID("myID"),
-								Name:      "test-node.test.ts.net.",
-								Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
-							}).View(),
-							Peers: []tailcfg.NodeView{
-								(&tailcfg.Node{
+							PeersChanged: []*tailcfg.Node{
+								{
 									StableID:  tailcfg.StableNodeID("fooID"),
 									Name:      "foo.tailnetxyz.ts.net.",
 									Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.2/32")},
-								}).View(),
+								},
 							},
 						},
 						WantKubeSecret: map[string]string{
@@ -1141,6 +1116,23 @@ func TestContainerBoot(t *testing.T) {
 							egressSvcTerminateURL(env.localAddrPort): 200,
 						},
 					},
+					{
+						Notify: &ipn.Notify{
+							PeersChanged: []*tailcfg.Node{{
+								StableID:  tailcfg.StableNodeID("fooID"),
+								Name:      "foo.tailnetxyz.ts.net.",
+								Addresses: []netip.Prefix{netip.MustParsePrefix("100.64.0.3/32")},
+							}},
+						},
+						WantKubeSecret: map[string]string{
+							"egress-services":   string(mustJSON(t, egressStatusUpdated)),
+							"authkey":           "tskey-key",
+							"device_fqdn":       "test-node.test.ts.net.",
+							"device_id":         "myID",
+							"device_ips":        `["100.64.0.1"]`,
+							kubetypes.KeyCapVer: capver,
+						},
+					},
 				},
 			}
 		},
@@ -1295,17 +1287,8 @@ func TestContainerBoot(t *testing.T) {
 						t.Fatalf("phase %d: updating mtime for %q: %v", i, path, err)
 					}
 				}
-				nmForFake := p.NetMap
-				if nmForFake == nil && p.Notify != nil && p.Notify.SelfChange != nil {
-					// Synthesize a minimal netmap from SelfChange so
-					// containerboot's NetMap() fetch returns
-					// something usable when the test only set Notify.
-					nmForFake = &netmap.NetworkMap{
-						SelfNode: p.Notify.SelfChange.View(),
-					}
-				}
-				if nmForFake != nil {
-					env.lapi.SetNetMap(nmForFake)
+				if p.Notify != nil && p.Notify.InitialStatus == nil {
+					p.Notify.InitialStatus = statusFromNotify(p.Notify)
 				}
 				env.lapi.Notify(p.Notify)
 				if p.Signal != nil {
@@ -1499,7 +1482,6 @@ type localAPI struct {
 	sync.Mutex
 	cond   *sync.Cond
 	notify *ipn.Notify
-	netmap *netmap.NetworkMap // served by /localapi/v0/netmap
 }
 
 func (lc *localAPI) Start() error {
@@ -1536,44 +1518,45 @@ func (lc *localAPI) Notify(n *ipn.Notify) {
 	lc.cond.Broadcast()
 }
 
-// SetNetMap installs the netmap that the fake /localapi/v0/netmap endpoint
-// will return.
-func (lc *localAPI) SetNetMap(nm *netmap.NetworkMap) {
-	lc.Lock()
-	defer lc.Unlock()
-	lc.netmap = nm
+func statusFromNotify(n *ipn.Notify) *ipnstate.Status {
+	st := new(ipnstate.Status)
+	if n.State != nil {
+		st.BackendState = n.State.String()
+	}
+	if n.SelfChange != nil {
+		st.Self = peerStatusFromNode(n.SelfChange.View())
+	}
+	if len(n.PeersChanged) != 0 {
+		st.Peer = map[key.NodePublic]*ipnstate.PeerStatus{}
+		for _, p := range n.PeersChanged {
+			pv := p.View()
+			st.Peer[pv.Key()] = peerStatusFromNode(pv)
+		}
+	}
+	return st
+}
+
+func peerStatusFromNode(n tailcfg.NodeView) *ipnstate.PeerStatus {
+	ps := &ipnstate.PeerStatus{
+		ID:        n.StableID(),
+		NodeID:    n.ID(),
+		PublicKey: n.Key(),
+		DNSName:   n.Name(),
+	}
+	for _, p := range n.Addresses().All() {
+		if p.IsSingleIP() {
+			ps.TailscaleIPs = append(ps.TailscaleIPs, p.Addr())
+		}
+	}
+	if n.AllowedIPs().Len() != 0 {
+		v := n.AllowedIPs()
+		ps.AllowedIPs = &v
+	}
+	return ps
 }
 
 func (lc *localAPI) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	switch r.URL.Path {
-	case "/localapi/v0/netmap":
-		w.Header().Set("Content-Type", "application/json")
-		lc.Lock()
-		nm := lc.netmap
-		lc.Unlock()
-		if nm == nil {
-			http.Error(w, "no netmap", http.StatusServiceUnavailable)
-			return
-		}
-		json.NewEncoder(w).Encode(nm)
-		return
-	case "/localapi/v0/debug":
-		// containerboot fetches the netmap via the "current-netmap"
-		// debug action; serve it like /localapi/v0/netmap above.
-		if r.URL.Query().Get("action") != "current-netmap" {
-			http.Error(w, "unsupported debug action", http.StatusNotFound)
-			return
-		}
-		w.Header().Set("Content-Type", "application/json")
-		lc.Lock()
-		nm := lc.netmap
-		lc.Unlock()
-		if nm == nil {
-			http.Error(w, "no netmap", http.StatusServiceUnavailable)
-			return
-		}
-		json.NewEncoder(w).Encode(nm)
-		return
 	case "/localapi/v0/serve-config":
 		switch r.Method {
 		case "GET":

cmd/containerboot/serve.go

@@ -24,7 +24,6 @@ import (
 	"tailscale.com/kube/kubetypes"
 	klc "tailscale.com/kube/localclient"
 	"tailscale.com/kube/services"
-	"tailscale.com/types/netmap"
 )
 
 // watchServeConfigChanges watches path for changes, and when it sees one, reads
@@ -142,13 +141,6 @@ func refreshAdvertiseServices(ctx context.Context, sc *ipn.ServeConfig, lc klc.L
 	return nil
 }
 
-func certDomainFromNetmap(nm *netmap.NetworkMap) string {
-	if len(nm.DNS.CertDomains) == 0 {
-		return ""
-	}
-	return nm.DNS.CertDomains[0]
-}
-
 func updateServeConfig(ctx context.Context, sc *ipn.ServeConfig, certDomain string, lc klc.LocalClient) error {
 	if !isValidHTTPSConfig(certDomain, sc) {
 		return nil

control/controlclient/map_test.go

@@ -1317,6 +1317,56 @@ func (nu *countingNetmapUpdater) UpdateFullNetmap(nm *netmap.NetworkMap) {
 	nu.full.Add(1)
 }
 
+type countingDeltaNetmapUpdater struct {
+	countingNetmapUpdater
+	delta atomic.Int64
+}
+
+func (nu *countingDeltaNetmapUpdater) UpdateNetmapDelta([]netmap.NodeMutation) bool {
+	nu.delta.Add(1)
+	return true
+}
+
+func TestExistingPeerReplacementHandledIncrementally(t *testing.T) {
+	nu := &countingDeltaNetmapUpdater{}
+	ms := newTestMapSession(t, nu)
+	ctx := t.Context()
+
+	peer := &tailcfg.Node{
+		ID:         1,
+		StableID:   "peer",
+		Name:       "peer.example.ts.net.",
+		Key:        key.NewNode().Public(),
+		DiscoKey:   key.NewDisco().Public(),
+		Addresses:  []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
+		AllowedIPs: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
+		Hostinfo:   (&tailcfg.Hostinfo{}).View(),
+	}
+	if err := ms.handleNonKeepAliveMapResponse(ctx, &tailcfg.MapResponse{
+		Node:  &tailcfg.Node{Name: "self.example.ts.net."},
+		Peers: []*tailcfg.Node{peer},
+	}, false); err != nil {
+		t.Fatal(err)
+	}
+	if got := nu.full.Load(); got != 1 {
+		t.Fatalf("full updates after initial response = %d; want 1", got)
+	}
+
+	replacement := peer.Clone()
+	replacement.AllowedIPs = append(replacement.AllowedIPs, netip.MustParsePrefix("100.64.0.2/32"))
+	if err := ms.handleNonKeepAliveMapResponse(ctx, &tailcfg.MapResponse{
+		PeersChanged: []*tailcfg.Node{replacement},
+	}, false); err != nil {
+		t.Fatal(err)
+	}
+	if got := nu.full.Load(); got != 1 {
+		t.Errorf("full updates after route-changing peer replacement = %d; want 1", got)
+	}
+	if got := nu.delta.Load(); got != 1 {
+		t.Errorf("delta updates after route-changing peer replacement = %d; want 1", got)
+	}
+}
+
 // tests (*mapSession).patchifyPeersChanged; smaller tests are in TestPeerChangeDiff
 func TestPatchifyPeersChanged(t *testing.T) {
 	hi := (&tailcfg.Hostinfo{}).View()

flake.nix

@@ -164,4 +164,4 @@
     });
   };
 }
-# nix-direnv cache busting line: sha256-rueM6HBKbu8WBw4atwubJD3c0O95zAkUVeOkARDiX18=
+# nix-direnv cache busting line: sha256-pXdOQRF8EpZ+fFYhsEgAT04k3h88gdOZ42e0AMeV4Wc=

flakehashes.json

@@ -4,7 +4,7 @@
     "sri": "sha256-uskKJHUzzIQ74VuzoQKrlz+6tCY/YKnv+BjJduPwt6Q="
   },
   "vendor": {
-    "goModSum": "sha256-MqRZjijiKUKNgFmZmw6bMOfrU6HLh3iJYe+7lCKb0Uw=",
-    "sri": "sha256-rueM6HBKbu8WBw4atwubJD3c0O95zAkUVeOkARDiX18="
+    "goModSum": "sha256-nI9Dzn2PeLKj9mnskoHhwZNix+6H7pA4nlB75sDAn1U=",
+    "sri": "sha256-pXdOQRF8EpZ+fFYhsEgAT04k3h88gdOZ42e0AMeV4Wc="
   }
 }

go.mod

@@ -162,6 +162,7 @@ require (
 	github.com/armon/go-metrics v0.4.1 // indirect
 	github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2 // indirect
 	github.com/beevik/ntp v0.3.0 // indirect
+	github.com/benbjohnson/immutable v0.4.3
 	github.com/blang/semver/v4 v4.0.0 // indirect
 	github.com/boltdb/bolt v1.3.1 // indirect
 	github.com/bombsimon/wsl/v4 v4.2.1 // indirect

go.sum

@@ -187,6 +187,8 @@ github.com/axiomhq/hyperloglog v0.0.0-20240319100328-84253e514e02/go.mod h1:k08r
 github.com/beevik/ntp v0.2.0/go.mod h1:hIHWr+l3+/clUnF44zdK+CWW7fO8dR5cIylAQ76NRpg=
 github.com/beevik/ntp v0.3.0 h1:xzVrPrE4ziasFXgBVBZJDP0Wg/KpMwk2KHJ4Ba8GrDw=
 github.com/beevik/ntp v0.3.0/go.mod h1:hIHWr+l3+/clUnF44zdK+CWW7fO8dR5cIylAQ76NRpg=
+github.com/benbjohnson/immutable v0.4.3 h1:GYHcksoJ9K6HyAUpGxwZURrbTkXA0Dh4otXGqbhdrjA=
+github.com/benbjohnson/immutable v0.4.3/go.mod h1:qJIKKSmdqz1tVzNtst1DZzvaqOU1onk1rc03IeM3Owk=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=

ipn/backend.go

@@ -5,6 +5,7 @@ package ipn
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 	"time"
 
@@ -35,15 +36,27 @@ const (
 // ID tokens used by the Android client.
 const GoogleIDTokenType = "ts_android_google_login"
 
+var stateStrings = [...]string{
+	"NoState",
+	"InUseOtherUser",
+	"NeedsLogin",
+	"NeedsMachineAuth",
+	"Stopped",
+	"Starting",
+	"Running",
+}
+
 func (s State) String() string {
-	return [...]string{
-		"NoState",
-		"InUseOtherUser",
-		"NeedsLogin",
-		"NeedsMachineAuth",
-		"Stopped",
-		"Starting",
-		"Running"}[s]
+	return stateStrings[s]
+}
+
+// StateFromString parses s as a State string value.
+func StateFromString(s string) (_ State, ok bool) {
+	i := slices.Index(stateStrings[:], s)
+	if i == -1 {
+		return NoState, false
+	}
+	return State(i), true
 }
 
 // EngineStatus contains WireGuard engine stats.

ipn/ipnlocal/local.go

@@ -1417,6 +1417,7 @@ func (b *LocalBackend) updateStatusLocked(sb *ipnstate.StatusBuilder) {
 		}
 		if nm != nil {
 			s.CertDomains = append([]string(nil), nm.DNS.CertDomains...)
+			s.ExtraRecords = append([]tailcfg.DNSRecord(nil), nm.DNS.ExtraRecords...)
 			s.MagicDNSSuffix = nm.MagicDNSSuffix()
 			if s.CurrentTailnet == nil {
 				s.CurrentTailnet = &ipnstate.TailnetStatus{}
@@ -2325,6 +2326,7 @@ func (b *LocalBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
 	defer b.mu.Unlock()
 
 	cn := b.currentNode()
+	needsAuthReconfig := netmapDeltaNeedsAuthReconfig(cn, muts)
 	cn.UpdateNetmapDelta(muts)
 
 	// Dispatch Upsert/Remove per-peer to magicsock, and any per-field
@@ -2348,6 +2350,9 @@ func (b *LocalBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
 		}
 	}
 	ms.UpdateNetmapDelta(muts)
+	if needsAuthReconfig {
+		b.authReconfigLocked()
+	}
 
 	// If auto exit nodes are enabled and our exit node went offline,
 	// we need to schedule picking a new one.
@@ -2411,6 +2416,33 @@ func (b *LocalBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
 	return true
 }
 
+func netmapDeltaNeedsAuthReconfig(cn *nodeBackend, muts []netmap.NodeMutation) bool {
+	for _, m := range muts {
+		switch m := m.(type) {
+		case netmap.NodeMutationUpsert:
+			old, ok := cn.NodeByID(m.Node.ID())
+			if !ok {
+				continue
+			}
+			if peerRouteConfigChanged(old, m.Node) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func peerRouteConfigChanged(old, new tailcfg.NodeView) bool {
+	return old.Key() != new.Key() ||
+		old.DiscoKey() != new.DiscoKey() ||
+		!views.SliceEqual(old.AllowedIPs(), new.AllowedIPs()) ||
+		old.Expired() != new.Expired() ||
+		old.IsJailed() != new.IsJailed() ||
+		old.IsWireGuardOnly() != new.IsWireGuardOnly() ||
+		old.SelfNodeV4MasqAddrForThisPeer() != new.SelfNodeV4MasqAddrForThisPeer() ||
+		old.SelfNodeV6MasqAddrForThisPeer() != new.SelfNodeV6MasqAddrForThisPeer()
+}
+
 // UpdatePacketFilter implements [controlclient.PacketFilterUpdater].
 //
 // It is called by the controlclient when a MapResponse carries a new packet
@@ -2506,7 +2538,7 @@ func mutationsAreWorthyOfRecalculatingSuggestedExitNode(muts []netmap.NodeMutati
 // [tailcfg.PeerChange] for use in [ipn.Notify.PeerChangedPatch]. Multiple
 // mutations against the same node are merged into a single PeerChange.
 //
-// Add/Remove mutations are skipped (they ride
+// Upsert/Remove mutations are skipped (they ride
 // [ipn.Notify.PeersChanged]/[ipn.Notify.PeersRemoved]). Any other mutation
 // type that doesn't fit a [tailcfg.PeerChange] causes ok=false; the caller
 // should fall back to a full netmap rebuild.
@@ -5662,7 +5694,7 @@ func (b *LocalBackend) authReconfigLocked() {
 
 	cn := b.currentNode()
 
-	nm := cn.NetMap()
+	nm := cn.netMapWithPeers()
 	if nm == nil {
 		b.logf("[v1] authReconfig: netmap not yet valid. Skipping.")
 		return

ipn/ipnlocal/state_test.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"math/rand/v2"
 	"net/netip"
+	"slices"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -1573,6 +1574,48 @@ func TestEngineReconfigOnStateChange(t *testing.T) {
 	}
 }
 
+func TestEngineReconfigOnPeerRouteDelta(t *testing.T) {
+	connect := &ipn.MaskedPrefs{Prefs: ipn.Prefs{WantRunning: true}, WantRunningSet: true}
+	peerAddr := netip.MustParsePrefix("100.64.1.1/32")
+	vipAddr := netip.MustParsePrefix("100.99.99.99/32")
+
+	peer := makePeer(1, withName("node-1"), withAddresses(peerAddr))
+	peerStruct := peer.AsStruct()
+	peerStruct.AllowedIPs = []netip.Prefix{peerAddr}
+	peer = peerStruct.View()
+
+	nm := buildNetmapWithPeers(
+		makePeer(2, withName("node-2"), withAddresses(netip.MustParsePrefix("100.64.1.2/32"))),
+		peer,
+	)
+
+	lb, engine, cc := newLocalBackendWithMockEngineAndControl(t, false)
+	mustDo(t)(lb.Start(ipn.Options{}))
+	mustDo2(t)(lb.EditPrefs(connect))
+	cc().authenticated(nm)
+
+	replacement := nm.Peers[0].AsStruct()
+	replacement.AllowedIPs = append(replacement.AllowedIPs, vipAddr)
+	if !lb.UpdateNetmapDelta([]netmap.NodeMutation{netmap.NodeMutationUpsert{Node: replacement.View()}}) {
+		t.Fatal("UpdateNetmapDelta = false, want true")
+	}
+
+	cfg := engine.Config()
+	if cfg == nil {
+		t.Fatal("engine config is nil")
+	}
+	for _, peer := range cfg.Peers {
+		if peer.PublicKey != replacement.Key {
+			continue
+		}
+		if !slices.Contains(peer.AllowedIPs, vipAddr) {
+			t.Fatalf("peer AllowedIPs = %v; want %v", peer.AllowedIPs, vipAddr)
+		}
+		return
+	}
+	t.Fatalf("engine config missing peer %v", replacement.Key.ShortString())
+}
+
 // TestSendPreservesAuthURL tests that wgengine updates arriving in the middle of
 // processing an auth URL doesn't result in the auth URL being cleared.
 func TestSendPreservesAuthURL(t *testing.T) {

ipn/ipnstate/ipnstate.go

@@ -73,6 +73,9 @@ type Status struct {
 	// trailing periods, and without any "_acme-challenge." prefix.
 	CertDomains []string
 
+	// ExtraRecords contains extra DNS records to add to the DNS resolver.
+	ExtraRecords []tailcfg.DNSRecord
+
 	// Peer is the state of each peer, keyed by each peer's current public key.
 	Peer map[key.NodePublic]*PeerStatus
 

shell.nix

@@ -16,4 +16,4 @@
 ) {
   src =  ./.;
 }).shellNix
-# nix-direnv cache busting line: sha256-rueM6HBKbu8WBw4atwubJD3c0O95zAkUVeOkARDiX18=
+# nix-direnv cache busting line: sha256-pXdOQRF8EpZ+fFYhsEgAT04k3h88gdOZ42e0AMeV4Wc=

tstest/integration/integration_test.go

@@ -914,6 +914,96 @@ func TestIncrementalMapUpdatePeersRemoved(t *testing.T) {
 	d2.MustCleanShutdown(t)
 }
 
+// TestIncrementalMapUpdatePeerAllowedIPsReachability verifies that an incremental
+// peer upsert changing a peer's AllowedIPs reprograms the local WireGuard config.
+// This covers VIP additions at runtime, where the VIP route is not reachable
+// before the map mutation but is reachable over TSMP afterward.
+func TestIncrementalMapUpdatePeerAllowedIPsReachability(t *testing.T) {
+	tstest.Shard(t)
+	tstest.Parallel(t)
+	env := NewTestEnv(t)
+
+	n1 := NewTestNode(t, env)
+	d1 := n1.StartDaemon()
+	defer d1.MustCleanShutdown(t)
+	n1.AwaitListening()
+	n1.MustUp()
+	n1.AwaitRunning()
+
+	n2 := NewTestNode(t, env)
+	d2 := n2.StartDaemon()
+	defer d2.MustCleanShutdown(t)
+	n2.AwaitListening()
+	n2.MustUp()
+	n2.AwaitRunning()
+
+	n1Status := n1.MustStatus()
+	n2Status := n2.MustStatus()
+	tnode1 := env.Control.Node(n1Status.Self.PublicKey)
+	if tnode1 == nil {
+		t.Fatalf("control has no node for %v", n1Status.Self.PublicKey)
+	}
+	tnode2 := env.Control.Node(n2Status.Self.PublicKey)
+	if tnode2 == nil {
+		t.Fatalf("control has no node for %v", n2Status.Self.PublicKey)
+	}
+
+	vip := netip.MustParseAddr("100.99.99.99")
+	vipPrefix := netip.PrefixFrom(vip, vip.BitLen())
+
+	if err := n1.Tailscale("ping", "--tsmp", "--c=1", "--timeout=5s", n2.AwaitIP4().String()).Run(); err != nil {
+		t.Fatalf("initial ping n1 -> n2: %v", err)
+	}
+	if err := n1.Tailscale("ping", "--tsmp", "--c=1", "--timeout=1s", vip.String()).Run(); err == nil {
+		t.Fatalf("ping n1 -> n2 VIP %v before AllowedIPs delta succeeded unexpectedly", vip)
+	}
+
+	mr, err := env.Control.MapResponse(&tailcfg.MapRequest{NodeKey: tnode1.Key})
+	if err != nil {
+		t.Fatalf("MapResponse: %v", err)
+	}
+	var replacement *tailcfg.Node
+	for _, p := range mr.Peers {
+		if p.ID == tnode2.ID {
+			replacement = p.Clone()
+			break
+		}
+	}
+	if replacement == nil {
+		t.Fatalf("MapResponse for n1 has no peer n2")
+	}
+
+	replacement.AllowedIPs = append(replacement.AllowedIPs, vipPrefix)
+	if !env.Control.AddRawMapResponse(tnode1.Key, &tailcfg.MapResponse{
+		PeersChanged: []*tailcfg.Node{replacement},
+	}) {
+		t.Fatalf("failed to add map response")
+	}
+
+	if err := tstest.WaitFor(5*time.Second, func() error {
+		st := n1.MustStatus()
+		p, ok := st.Peer[tnode2.Key]
+		if !ok {
+			return fmt.Errorf("node 1 doesn't see node 2 as a peer")
+		}
+		if p.AllowedIPs == nil {
+			return fmt.Errorf("node 1 sees node 2 with no AllowedIPs")
+		}
+		for _, allowedIP := range p.AllowedIPs.All() {
+			if allowedIP == vipPrefix {
+				return nil
+			}
+		}
+		return fmt.Errorf("node 1 sees node 2 AllowedIPs %v; want %v", p.AllowedIPs, vipPrefix)
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := n1.Tailscale("ping", "--tsmp", "--c=1", "--timeout=5s", vip.String()).Run(); err != nil {
+		t.Fatalf("ping n1 -> n2 VIP %v after AllowedIPs delta: %v", vip, err)
+	}
+}
+
 func TestNodeAddressIPFields(t *testing.T) {
 	tstest.Shard(t)
 	flakytest.Mark(t, "https://github.com/tailscale/tailscale/issues/7008")