152 lines
3.6 KiB
Go
152 lines
3.6 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package derphttp
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import (
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"context"
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"sync"
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"time"
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"tailscale.com/derp"
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"tailscale.com/types/key"
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"tailscale.com/types/logger"
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)
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// RunWatchConnectionLoop loops until ctx is done, sending WatchConnectionChanges and subscribing to
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// connection changes.
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//
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// If the server's public key is ignoreServerKey, RunWatchConnectionLoop returns.
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//
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// Otherwise, the add and remove funcs are called as clients come & go.
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//
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// infoLogf, if non-nil, is the logger to write periodic status
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// updates about how many peers are on the server. Error log output is
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// set to the c's logger, regardless of infoLogf's value.
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//
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// To force RunWatchConnectionLoop to return quickly, its ctx needs to
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// be closed, and c itself needs to be closed.
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func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key.NodePublic, infoLogf logger.Logf, add, remove func(key.NodePublic)) {
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if infoLogf == nil {
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infoLogf = logger.Discard
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}
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logf := c.logf
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const retryInterval = 5 * time.Second
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const statusInterval = 10 * time.Second
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var (
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mu sync.Mutex
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present = map[key.NodePublic]bool{}
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loggedConnected = false
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)
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clear := func() {
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mu.Lock()
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defer mu.Unlock()
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if len(present) == 0 {
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return
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}
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logf("reconnected; clearing %d forwarding mappings", len(present))
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for k := range present {
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remove(k)
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}
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present = map[key.NodePublic]bool{}
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}
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lastConnGen := 0
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lastStatus := c.clock.Now()
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logConnectedLocked := func() {
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if loggedConnected {
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return
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}
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infoLogf("connected; %d peers", len(present))
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loggedConnected = true
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}
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const logConnectedDelay = 200 * time.Millisecond
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timer := c.clock.AfterFunc(2*time.Second, func() {
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mu.Lock()
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defer mu.Unlock()
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logConnectedLocked()
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})
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defer timer.Stop()
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updatePeer := func(k key.NodePublic, isPresent bool) {
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if isPresent {
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add(k)
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} else {
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remove(k)
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}
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mu.Lock()
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defer mu.Unlock()
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if isPresent {
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present[k] = true
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if !loggedConnected {
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timer.Reset(logConnectedDelay)
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}
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} else {
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// If we got a peerGone message, that means the initial connection's
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// flood of peerPresent messages is done, so we can log already:
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logConnectedLocked()
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delete(present, k)
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}
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}
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sleep := func(d time.Duration) {
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t, tChannel := c.clock.NewTimer(d)
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select {
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case <-ctx.Done():
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t.Stop()
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case <-tChannel:
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}
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}
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for ctx.Err() == nil {
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err := c.WatchConnectionChanges()
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if err != nil {
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clear()
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logf("WatchConnectionChanges: %v", err)
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sleep(retryInterval)
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continue
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}
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if c.ServerPublicKey() == ignoreServerKey {
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logf("detected self-connect; ignoring host")
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return
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}
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for {
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m, connGen, err := c.RecvDetail()
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if err != nil {
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clear()
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logf("Recv: %v", err)
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sleep(retryInterval)
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break
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}
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if connGen != lastConnGen {
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lastConnGen = connGen
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clear()
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}
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switch m := m.(type) {
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case derp.PeerPresentMessage:
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updatePeer(key.NodePublic(m), true)
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case derp.PeerGoneMessage:
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switch m.Reason {
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case derp.PeerGoneReasonDisconnected:
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// Normal case, log nothing
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case derp.PeerGoneReasonNotHere:
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logf("Recv: peer %s not connected to %s",
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key.NodePublic(m.Peer).ShortString(), c.ServerPublicKey().ShortString())
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default:
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logf("Recv: peer %s not at server %s for unknown reason %v",
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key.NodePublic(m.Peer).ShortString(), c.ServerPublicKey().ShortString(), m.Reason)
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}
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updatePeer(key.NodePublic(m.Peer), false)
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default:
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continue
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}
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if now := c.clock.Now(); now.Sub(lastStatus) > statusInterval {
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lastStatus = now
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infoLogf("%d peers", len(present))
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}
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}
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}
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}
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