Update dependencies

vendor/tailscale.com/derp/derphttp/mesh_client.go

@@ -0,0 +1,177 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package derphttp
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"tailscale.com/derp"
+	"tailscale.com/types/key"
+	"tailscale.com/types/logger"
+)
+
+var retryInterval = 5 * time.Second
+
+// testHookWatchLookConnectResult, if non-nil for tests, is called by RunWatchConnectionLoop
+// with the connect result. If it returns false, the loop ends.
+var testHookWatchLookConnectResult func(connectError error, wasSelfConnect bool) (keepRunning bool)
+
+// RunWatchConnectionLoop loops until ctx is done, sending
+// WatchConnectionChanges and subscribing to connection changes.
+//
+// If the server's public key is ignoreServerKey, RunWatchConnectionLoop
+// returns.
+//
+// Otherwise, the add and remove funcs are called as clients come & go.
+// Note that add is called for every new connection and remove is only
+// called for the final disconnection. See https://github.com/tailscale/tailscale/issues/13566.
+// This behavior will likely change. Callers should do their own accounting
+// and dup suppression as needed.
+//
+// infoLogf, if non-nil, is the logger to write periodic status updates about
+// how many peers are on the server. Error log output is set to the c's logger,
+// regardless of infoLogf's value.
+//
+// To force RunWatchConnectionLoop to return quickly, its ctx needs to be
+// closed, and c itself needs to be closed.
+//
+// It is a fatal error to call this on an already-started Client without having
+// initialized Client.WatchConnectionChanges to true.
+//
+// If the DERP connection breaks and reconnects, remove will be called for all
+// previously seen peers, with Reason type PeerGoneReasonSynthetic. Those
+// clients are likely still connected and their add message will appear after
+// reconnect.
+func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key.NodePublic, infoLogf logger.Logf, add func(derp.PeerPresentMessage), remove func(derp.PeerGoneMessage)) {
+	if !c.WatchConnectionChanges {
+		if c.isStarted() {
+			panic("invalid use of RunWatchConnectionLoop on already-started Client without setting Client.RunWatchConnectionLoop")
+		}
+		c.WatchConnectionChanges = true
+	}
+	if infoLogf == nil {
+		infoLogf = logger.Discard
+	}
+	logf := c.logf
+	const statusInterval = 10 * time.Second
+	var (
+		mu              sync.Mutex
+		present         = map[key.NodePublic]bool{}
+		loggedConnected = false
+	)
+	clear := func() {
+		mu.Lock()
+		defer mu.Unlock()
+		if len(present) == 0 {
+			return
+		}
+		logf("reconnected; clearing %d forwarding mappings", len(present))
+		for k := range present {
+			remove(derp.PeerGoneMessage{Peer: k, Reason: derp.PeerGoneReasonMeshConnBroke})
+		}
+		present = map[key.NodePublic]bool{}
+	}
+	lastConnGen := 0
+	lastStatus := c.clock.Now()
+	logConnectedLocked := func() {
+		if loggedConnected {
+			return
+		}
+		infoLogf("connected; %d peers", len(present))
+		loggedConnected = true
+	}
+
+	const logConnectedDelay = 200 * time.Millisecond
+	timer := c.clock.AfterFunc(2*time.Second, func() {
+		mu.Lock()
+		defer mu.Unlock()
+		logConnectedLocked()
+	})
+	defer timer.Stop()
+
+	updatePeer := func(k key.NodePublic, isPresent bool) {
+		mu.Lock()
+		defer mu.Unlock()
+		if isPresent {
+			present[k] = true
+			if !loggedConnected {
+				timer.Reset(logConnectedDelay)
+			}
+		} else {
+			// If we got a peerGone message, that means the initial connection's
+			// flood of peerPresent messages is done, so we can log already:
+			logConnectedLocked()
+			delete(present, k)
+		}
+	}
+
+	sleep := func(d time.Duration) {
+		t, tChannel := c.clock.NewTimer(d)
+		select {
+		case <-ctx.Done():
+			t.Stop()
+		case <-tChannel:
+		}
+	}
+
+	for ctx.Err() == nil {
+		// Make sure we're connected before calling s.ServerPublicKey.
+		_, _, err := c.connect(ctx, "RunWatchConnectionLoop")
+		if err != nil {
+			if f := testHookWatchLookConnectResult; f != nil && !f(err, false) {
+				return
+			}
+			logf("mesh connect: %v", err)
+			sleep(retryInterval)
+			continue
+		}
+		selfConnect := c.ServerPublicKey() == ignoreServerKey
+		if f := testHookWatchLookConnectResult; f != nil && !f(err, selfConnect) {
+			return
+		}
+		if selfConnect {
+			logf("detected self-connect; ignoring host")
+			return
+		}
+		for {
+			m, connGen, err := c.RecvDetail()
+			if err != nil {
+				clear()
+				logf("Recv: %v", err)
+				sleep(retryInterval)
+				break
+			}
+			if connGen != lastConnGen {
+				lastConnGen = connGen
+				clear()
+			}
+			switch m := m.(type) {
+			case derp.PeerPresentMessage:
+				add(m)
+				updatePeer(m.Key, true)
+			case derp.PeerGoneMessage:
+				switch m.Reason {
+				case derp.PeerGoneReasonDisconnected:
+					// Normal case, log nothing
+				case derp.PeerGoneReasonNotHere:
+					logf("Recv: peer %s not connected to %s",
+						key.NodePublic(m.Peer).ShortString(), c.ServerPublicKey().ShortString())
+				default:
+					logf("Recv: peer %s not at server %s for unknown reason %v",
+						key.NodePublic(m.Peer).ShortString(), c.ServerPublicKey().ShortString(), m.Reason)
+				}
+				remove(m)
+				updatePeer(m.Peer, false)
+			default:
+				continue
+			}
+			if now := c.clock.Now(); now.Sub(lastStatus) > statusInterval {
+				lastStatus = now
+				infoLogf("%d peers", len(present))
+			}
+		}
+	}
+}