temp timing logs

client/internal/engine.go

@@ -14,6 +14,7 @@ import (
 	"sort"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/hashicorp/go-multierror"
@@ -88,6 +89,13 @@ var ErrResetConnection = fmt.Errorf("reset connection")
 
 var ErrEngineAlreadyStarted = errors.New("engine already started")
 
+// engineRestartCount and engineLastRestart track client-restart cadence across
+// engine recreations so a restart loop is distinguishable from rare restarts.
+var (
+	engineRestartCount atomic.Int64
+	engineLastRestart  atomic.Int64
+)
+
 type EngineConfig struct {
 	WgPort      int
 	WgIfaceName string
@@ -909,14 +917,23 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 	if e.ctx.Err() != nil {
 		return e.ctx.Err()
 	}
+	serial := update.GetNetworkMap().GetSerial()
+	if nm := update.GetNetworkMap(); nm != nil {
+		log.Infof("sync update: serial=%d remotePeers=%d offlinePeers=%d routes=%d firewallRules=%d checks=%d configPresent=%v remotePeersEmpty=%v",
+			nm.GetSerial(), len(nm.GetRemotePeers()), len(nm.GetOfflinePeers()), len(nm.GetRoutes()),
+			len(nm.GetFirewallRules()), len(update.GetChecks()), update.GetNetbirdConfig() != nil, nm.GetRemotePeersIsEmpty())
+	} else {
+		log.Infof("sync update: config-only (no network map), configPresent=%v", update.GetNetbirdConfig() != nil)
+	}
 
 	if update.NetworkMap != nil && update.NetworkMap.PeerConfig != nil {
 		e.handleAutoUpdateVersion(update.NetworkMap.PeerConfig.AutoUpdate)
 	}
-
+	startTime := time.Now()
 	if err := e.updateNetbirdConfig(update.GetNetbirdConfig()); err != nil {
 		return err
 	}
+	log.Infof("netbird config updated in %s, serial=%d", time.Since(startTime), serial)
 
 	// Posture checks are bound to the network map presence:
 	//   NetworkMap != nil, checks present -> apply the received checks
@@ -927,17 +944,21 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 	if nm == nil {
 		return nil
 	}
-
+	startTime = time.Now()
 	if err := e.updateChecksIfNew(update.Checks); err != nil {
 		return err
 	}
+	log.Infof("checks updated in %s, serial=%d", time.Since(startTime), serial)
 
+	startTime = time.Now()
 	e.persistSyncResponse(update)
-
+	log.Infof("sync response persisted in %s, serial=%d", time.Since(startTime), serial)
 	// only apply new changes and ignore old ones
+	startTime = time.Now()
 	if err := e.updateNetworkMap(nm); err != nil {
 		return err
 	}
+	log.Infof("network map updated in %s, serial=%d", time.Since(startTime), serial)
 
 	e.statusRecorder.PublishEvent(cProto.SystemEvent_INFO, cProto.SystemEvent_SYSTEM, "Network map updated", "", nil)
 
@@ -1357,44 +1378,56 @@ func (e *Engine) updateNetworkMap(networkMap *mgmProto.NetworkMap) error {
 
 	dnsConfig := toDNSConfig(protoDNSConfig, e.wgInterface.Address())
 
+	startTime := time.Now()
 	if err := e.dnsServer.UpdateDNSServer(serial, dnsConfig); err != nil {
 		log.Errorf("failed to update dns server, err: %v", err)
 	}
+	log.Infof("updated dns server in %v, serial=%d", time.Since(startTime), serial)
 
 	e.routeManager.SetDNSForwarderPort(dnsConfig.ForwarderPort)
 
 	// apply routes first, route related actions might depend on routing being enabled
+	startTime = time.Now()
 	routes := toRoutes(networkMap.GetRoutes())
 	serverRoutes, clientRoutes := e.routeManager.ClassifyRoutes(routes)
-
+	log.Infof("updated routes in %v, serial=%d", time.Since(startTime), serial)
 	// lazy mgr needs to be aware of which routes are available before they are applied
 	if e.connMgr != nil {
 		e.connMgr.UpdateRouteHAMap(clientRoutes)
 		log.Debugf("updated lazy connection manager with %d HA groups", len(clientRoutes))
 	}
 
+	startTime = time.Now()
 	dnsRouteFeatureFlag := toDNSFeatureFlag(networkMap)
 	if err := e.routeManager.UpdateRoutes(serial, serverRoutes, clientRoutes, dnsRouteFeatureFlag); err != nil {
 		log.Errorf("failed to update routes: %v", err)
 	}
+	log.Infof("updated routes in %v, serial=%d", time.Since(startTime), serial)
 
+	startTime = time.Now()
 	if e.acl != nil {
 		e.acl.ApplyFiltering(networkMap, dnsRouteFeatureFlag)
 	}
+	log.Infof("updated filtering in %v, serial=%d", time.Since(startTime), serial)
 
+	startTime = time.Now()
 	fwdEntries := toRouteDomains(e.config.WgPrivateKey.PublicKey().String(), routes)
 	e.updateDNSForwarder(dnsRouteFeatureFlag, fwdEntries)
+	log.Infof("updated DNS forwarder in %v, serial=%d", time.Since(startTime), serial)
 
+	startTime = time.Now()
 	// Ingress forward rules
 	forwardingRules, err := e.updateForwardRules(networkMap.GetForwardingRules())
 	if err != nil {
 		log.Errorf("failed to update forward rules, err: %v", err)
 	}
+	log.Infof("updated forward rules in %v, serial=%d", time.Since(startTime), serial)
 
 	log.Debugf("got peers update from Management Service, total peers to connect to = %d", len(networkMap.GetRemotePeers()))
 
+	startTime = time.Now()
 	e.updateOfflinePeers(networkMap.GetOfflinePeers())
-
+	log.Infof("updated offline peers in %v, serial=%d", time.Since(startTime), serial)
 	// Filter out own peer from the remote peers list
 	localPubKey := e.config.WgPrivateKey.PublicKey().String()
 	remotePeers := make([]*mgmProto.RemotePeerConfig, 0, len(networkMap.GetRemotePeers()))
@@ -1412,20 +1445,24 @@ func (e *Engine) updateNetworkMap(networkMap *mgmProto.NetworkMap) error {
 			return err
 		}
 	} else {
+		startTime = time.Now()
 		err := e.removePeers(remotePeers)
 		if err != nil {
 			return err
 		}
-
+		log.Infof("removed peers in %v, serial=%d", time.Since(startTime), serial)
+		startTime = time.Now()
 		err = e.modifyPeers(remotePeers)
 		if err != nil {
 			return err
 		}
-
+		log.Infof("modified peers in %v, serial=%d", time.Since(startTime), serial)
+		startTime = time.Now()
 		err = e.addNewPeers(remotePeers)
 		if err != nil {
 			return err
 		}
+		log.Infof("added peers in %v, serial=%d", time.Since(startTime), serial)
 
 		e.statusRecorder.FinishPeerListModifications()
 
@@ -1438,9 +1475,11 @@ func (e *Engine) updateNetworkMap(networkMap *mgmProto.NetworkMap) error {
 		e.updateSSHServerAuth(networkMap.GetSshAuth())
 	}
 
+	startTime = time.Now()
 	// must set the exclude list after the peers are added. Without it the manager can not figure out the peers parameters from the store
 	excludedLazyPeers := e.toExcludedLazyPeers(forwardingRules, remotePeers)
 	e.connMgr.SetExcludeList(e.ctx, excludedLazyPeers)
+	log.Infof("updated lazy connection manager exclude list in %v, serial=%d", time.Since(startTime), serial)
 
 	e.networkSerial = serial
 
@@ -2171,7 +2210,14 @@ func (e *Engine) triggerClientRestart() {
 		return
 	}
 
-	log.Info("restarting engine")
+	// Cadence survives engine recreation (package-level), so a restart loop shows
+	// as a fast-climbing count with a short gap, distinct from rare intentional restarts.
+	n := engineRestartCount.Add(1)
+	var sinceLast time.Duration
+	if prev := engineLastRestart.Swap(time.Now().UnixNano()); prev != 0 {
+		sinceLast = time.Since(time.Unix(0, prev))
+	}
+	log.Infof("restarting engine (restart #%d, %s since previous)", n, sinceLast.Round(time.Second))
 	CtxGetState(e.ctx).Set(StatusConnecting)
 	_ = CtxGetState(e.ctx).Wrap(ErrResetConnection)
 	log.Infof("cancelling client context, engine will be recreated")

client/internal/peer/worker_ice.go

@@ -461,7 +461,7 @@ func (w *WorkerICE) createForwardedCandidate(srflxCandidate ice.Candidate, mappi
 }
 
 func (w *WorkerICE) onICESelectedCandidatePair(agent *icemaker.ThreadSafeAgent, c1, c2 ice.Candidate) {
-	w.log.Debugf("selected candidate pair [local <-> remote] -> [%s <-> %s], peer %s", c1.String(), c2.String(),
+	w.log.Infof("selected candidate pair [local <-> remote] -> [%s <-> %s], peer %s", c1.String(), c2.String(),
 		w.config.Key)
 
 	pairStat, ok := agent.GetSelectedCandidatePairStats()

shared/signal/client/grpc.go

@@ -78,6 +78,23 @@ type GrpcClient struct {
 	// transport-alive but no longer delivering messages. It is the source of
 	// truth IsHealthy reads, and is cleared once any frame is received again.
 	receiveStalled atomic.Bool
+	// receiveHandoffBlocked is set while the receive loop is parked handing a
+	// message to a busy decryption worker. The loop stops calling Recv (and
+	// markReceived) in that window, so the stream looks silent though it is
+	// healthy. The watchdog reads this to avoid misreading self-inflicted
+	// receive backpressure as a dead stream: reconnecting cannot help, since the
+	// new stream feeds the same worker, and only triggers a reconnect storm.
+	receiveHandoffBlocked atomic.Bool
+	// lastDecrypt holds the Unix-nano timestamp of the last message the decryption
+	// worker pulled off its queue. Diagnostic only: it lets a stall log show
+	// whether the worker was draining (busy) or idle when the stream went silent.
+	lastDecrypt atomic.Int64
+	// handoffWaitTotal, handoffWaitMax (nanos) and handoffWaitCount accumulate the
+	// time the receive loop spent blocked handing messages to the worker. This is
+	// time not spent reading the stream, so it quantifies receive backpressure.
+	handoffWaitTotal atomic.Int64
+	handoffWaitMax   atomic.Int64
+	handoffWaitCount atomic.Int64
 }
 
 // NewClient creates a new Signal client
@@ -353,6 +370,8 @@ func (c *GrpcClient) SendToStream(msg *proto.EncryptedMessage) error {
 
 // decryptMessage decrypts the body of the msg using Wireguard private key and Remote peer's public key
 func (c *GrpcClient) decryptMessage(msg *proto.EncryptedMessage) (*proto.Message, error) {
+	c.lastDecrypt.Store(time.Now().UnixNano())
+
 	remoteKey, err := wgtypes.ParseKey(msg.GetKey())
 	if err != nil {
 		return nil, err
@@ -439,6 +458,22 @@ func (c *GrpcClient) idleSinceReceive() time.Duration {
 	return time.Since(time.Unix(0, c.lastReceived.Load()))
 }
 
+// idleSinceDecrypt returns how long since the worker last pulled a message.
+// Diagnostic only: distinguishes a busy/wedged worker from an idle one.
+func (c *GrpcClient) idleSinceDecrypt() time.Duration {
+	return time.Since(time.Unix(0, c.lastDecrypt.Load()))
+}
+
+// receiveAlive reports whether the receive stream shows liveness: it delivered a
+// frame within the inactivity threshold, or the receive loop is currently parked
+// handing a message to a busy decryption worker. In the latter case the loop has
+// stopped calling Recv, so the stream looks silent while being healthy, and
+// reconnecting would not help, so the watchdog must treat it as alive.
+func (c *GrpcClient) receiveAlive() bool {
+	return c.idleSinceReceive() < receiveInactivityThreshold ||
+		c.receiveHandoffBlocked.Load()
+}
+
 // watchReceiveStream guards against a receive stream that is transport-alive but
 // no longer delivering messages. While the stream is idle past
 // receiveInactivityThreshold it sends a self-addressed probe that the Signal
@@ -450,18 +485,55 @@ func (c *GrpcClient) watchReceiveStream(ctx context.Context, cancelStream contex
 	defer ticker.Stop()
 
 	var probeSentAt time.Time
+	var holdLogged bool
+	var statTicks int
+	var lastStatTotal int64
 	for {
 		select {
 		case <-ctx.Done():
 			return
 		case <-ticker.C:
-			if c.idleSinceReceive() < receiveInactivityThreshold {
+			// Periodic backpressure summary so time lost to the worker handoff is
+			// visible even when no stall fires. Emitted ~once a minute and only
+			// when the wait grew, to stay quiet on a healthy stream.
+			if statTicks++; statTicks >= int(time.Minute/receiveWatchdogInterval) {
+				statTicks = 0
+				if total, max, count := c.handoffWaitStats(); int64(total) > lastStatTotal {
+					log.Infof("signal receive backpressure: handoffWaitTotal=%s (+%s last min) handoffWaitMax=%s handoffMsgs=%d",
+						total.Round(time.Second), (total - time.Duration(lastStatTotal)).Round(time.Millisecond),
+						max.Round(time.Millisecond), count)
+					lastStatTotal = int64(total)
+				}
+			}
+
+			if c.receiveAlive() {
+				// Attribute the case that matters in the field: silent past the
+				// threshold but held because the receive loop is parked on the
+				// worker handoff (backpressure), not a dead stream. Log once per
+				// hold episode so a persistent worker stall is visible at info.
+				if c.idleSinceReceive() >= receiveInactivityThreshold && c.receiveHandoffBlocked.Load() {
+					if !holdLogged {
+						total, max, count := c.handoffWaitStats()
+						log.Infof("signal receive idle %s, loop blocked on worker handoff (idleDecrypt=%s queueDepth=%d connState=%s handoffWaitTotal=%s handoffWaitMax=%s handoffMsgs=%d); holding stream",
+							c.idleSinceReceive().Round(time.Second), c.idleSinceDecrypt().Round(time.Second),
+							c.decryptionWorker.QueueLen(), c.signalConn.GetState(),
+							total.Round(time.Second), max.Round(time.Millisecond), count)
+						holdLogged = true
+					}
+				} else {
+					holdLogged = false
+				}
 				probeSentAt = time.Time{}
 				continue
 			}
+			holdLogged = false
 
 			if !probeSentAt.IsZero() && time.Since(probeSentAt) >= receiveProbeTimeout {
-				log.Warnf("signal receive stream stalled: no messages for %s and probe did not return, reconnecting", c.idleSinceReceive().Round(time.Second))
+				total, max, count := c.handoffWaitStats()
+				log.Warnf("signal receive stream stalled, reconnecting: idleRecv=%s idleDecrypt=%s handoffBlocked=%v queueDepth=%d connState=%s handoffWaitTotal=%s handoffWaitMax=%s handoffMsgs=%d probe did not return",
+					c.idleSinceReceive().Round(time.Second), c.idleSinceDecrypt().Round(time.Second),
+					c.receiveHandoffBlocked.Load(), c.decryptionWorker.QueueLen(), c.signalConn.GetState(),
+					total.Round(time.Second), max.Round(time.Millisecond), count)
 				c.receiveStalled.Store(true)
 				c.notifyDisconnected(errReceiveStreamStalled)
 				cancelStream()
@@ -517,12 +589,37 @@ func (c *GrpcClient) receive(stream proto.SignalExchange_ConnectStreamClient) er
 			continue
 		}
 
+		// The handoff blocks while the worker is busy, which parks this loop and
+		// stops Recv. Flag it so the watchdog does not read the resulting silence
+		// as a dead stream, and account the wait as receive backpressure.
+		handoffStart := time.Now()
+		c.receiveHandoffBlocked.Store(true)
 		if err := c.decryptionWorker.AddMsg(c.ctx, msg); err != nil {
 			log.Errorf("failed to add message to decryption worker: %v", err)
 		}
+		c.receiveHandoffBlocked.Store(false)
+		c.recordHandoffWait(time.Since(handoffStart))
 	}
 }
 
+// recordHandoffWait accumulates the time the receive loop was blocked handing a
+// message to the worker.
+func (c *GrpcClient) recordHandoffWait(d time.Duration) {
+	c.handoffWaitTotal.Add(int64(d))
+	c.handoffWaitCount.Add(1)
+	for {
+		cur := c.handoffWaitMax.Load()
+		if int64(d) <= cur || c.handoffWaitMax.CompareAndSwap(cur, int64(d)) {
+			break
+		}
+	}
+}
+
+// handoffWaitStats returns cumulative receive-loop handoff backpressure.
+func (c *GrpcClient) handoffWaitStats() (total, max time.Duration, count int64) {
+	return time.Duration(c.handoffWaitTotal.Load()), time.Duration(c.handoffWaitMax.Load()), c.handoffWaitCount.Load()
+}
+
 func (c *GrpcClient) startEncryptionWorker(handler func(msg *proto.Message) error) {
 	if c.decryptionWorker != nil {
 		return

shared/signal/client/watchdog_test.go

@@ -82,3 +82,27 @@ func TestReceiveProbeRoundTrips(t *testing.T) {
 		t.Fatal("self-addressed heartbeat did not round-trip back through the signal server")
 	}
 }
+
+// TestReceiveAliveTreatsHandoffBlockAsLiveness reproduces the false positive
+// where a busy decryption worker parks the receive loop on the worker handoff,
+// so Recv (and markReceived) stops firing even though the stream is healthy.
+// With the receive stream silent past the inactivity threshold but the loop
+// blocked on handoff, the watchdog must consider the stream alive rather than
+// tear it down (reconnecting feeds the same worker and would not help).
+func TestReceiveAliveTreatsHandoffBlockAsLiveness(t *testing.T) {
+	c := &GrpcClient{}
+
+	// Receive stream silent and the loop not blocked on handoff: genuinely stalled.
+	c.lastReceived.Store(time.Now().Add(-2 * receiveInactivityThreshold).UnixNano())
+	require.False(t, c.receiveAlive(), "silent stream with the receive loop idle must be treated as stalled")
+
+	// Receive stream silent but the loop is parked handing a message to a busy
+	// worker: self-inflicted backpressure, not a dead stream, must not tear down.
+	c.receiveHandoffBlocked.Store(true)
+	require.True(t, c.receiveAlive(), "a receive loop blocked on worker handoff must keep the stream alive")
+
+	// Handoff drained, loop back to reading, a frame just arrived: alive via the receive path.
+	c.receiveHandoffBlocked.Store(false)
+	c.markReceived()
+	require.True(t, c.receiveAlive(), "a freshly received frame must keep the stream alive")
+}

shared/signal/client/worker.go

@@ -32,6 +32,13 @@ func (w *Worker) AddMsg(ctx context.Context, msg *proto.EncryptedMessage) error
 	return nil
 }
 
+// QueueLen returns the number of messages buffered for decryption. Diagnostic
+// only: a non-empty queue while the receive stream is silent indicates the
+// receive loop is parked on the handoff rather than the stream being dead.
+func (w *Worker) QueueLen() int {
+	return len(w.encryptedMsgPool)
+}
+
 func (w *Worker) Work(ctx context.Context) {
 	for {
 		select {