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// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
//go:build !js && !ts_omit_debug
package wgengine
import (
"fmt"
"log"
"net/netip"
"runtime/pprof"
"strings"
"sync"
"time"
"tailscale.com/envknob"
"tailscale.com/feature/buildfeatures"
"tailscale.com/ipn/ipnstate"
"tailscale.com/net/dns"
"tailscale.com/net/packet"
"tailscale.com/tailcfg"
"tailscale.com/types/key"
"tailscale.com/types/netmap"
"tailscale.com/util/clientmetric"
"tailscale.com/wgengine/filter"
"tailscale.com/wgengine/router"
"tailscale.com/wgengine/wgcfg"
"tailscale.com/wgengine/wgint"
)
type watchdogEvent string
const (
Any watchdogEvent = "Any"
Reconfig watchdogEvent = "Reconfig"
ResetAndStop watchdogEvent = "ResetAndStop"
SetFilter watchdogEvent = "SetFilter"
SetJailedFilter watchdogEvent = "SetJailedFilter"
SetStatusCallback watchdogEvent = "SetStatusCallback"
UpdateStatus watchdogEvent = "UpdateStatus"
RequestStatus watchdogEvent = "RequestStatus"
SetNetworkMap watchdogEvent = "SetNetworkMap"
Ping watchdogEvent = "Ping"
Close watchdogEvent = "Close"
PeerForIPEvent watchdogEvent = "PeerForIP"
)
var (
watchdogMetrics = map[watchdogEvent]*clientmetric.Metric{
Any: clientmetric.NewCounter("watchdog_timeout_any_total"),
Reconfig: clientmetric.NewCounter("watchdog_timeout_reconfig"),
ResetAndStop: clientmetric.NewCounter("watchdog_timeout_resetandstop"),
SetFilter: clientmetric.NewCounter("watchdog_timeout_setfilter"),
SetJailedFilter: clientmetric.NewCounter("watchdog_timeout_setjailedfilter"),
SetStatusCallback: clientmetric.NewCounter("watchdog_timeout_setstatuscallback"),
UpdateStatus: clientmetric.NewCounter("watchdog_timeout_updatestatus"),
RequestStatus: clientmetric.NewCounter("watchdog_timeout_requeststatus"),
SetNetworkMap: clientmetric.NewCounter("watchdog_timeout_setnetworkmap"),
Ping: clientmetric.NewCounter("watchdog_timeout_ping"),
Close: clientmetric.NewCounter("watchdog_timeout_close"),
PeerForIPEvent: clientmetric.NewCounter("watchdog_timeout_peerforipevent"),
}
)
// NewWatchdog wraps an Engine and makes sure that all methods complete
// within a reasonable amount of time.
//
// If they do not, the watchdog crashes the process.
func NewWatchdog(e Engine) Engine {
if envknob.Bool("TS_DEBUG_DISABLE_WATCHDOG") {
return e
}
return &watchdogEngine{
wrap: e,
logf: log.Printf,
fatalf: log.Fatalf,
maxWait: 45 * time.Second,
inFlight: make(map[inFlightKey]time.Time),
}
}
type inFlightKey struct {
op watchdogEvent
ctr uint64
}
type watchdogEngine struct {
wrap Engine
logf func(format string, args ...any)
fatalf func(format string, args ...any)
maxWait time.Duration
// Track the start time(s) of in-flight operations
inFlightMu sync.Mutex
inFlight map[inFlightKey]time.Time
inFlightCtr uint64
}
func (e *watchdogEngine) watchdogErr(event watchdogEvent, fn func() error) error {
// Track all in-flight operations so we can print more useful error
// messages on watchdog failure
e.inFlightMu.Lock()
key := inFlightKey{
op: event,
ctr: e.inFlightCtr,
}
e.inFlightCtr++
e.inFlight[key] = time.Now()
e.inFlightMu.Unlock()
defer func() {
e.inFlightMu.Lock()
defer e.inFlightMu.Unlock()
delete(e.inFlight, key)
}()
errCh := make(chan error)
go func() {
errCh <- fn()
}()
t := time.NewTimer(e.maxWait)
select {
case err := <-errCh:
t.Stop()
return err
case <-t.C:
buf := new(strings.Builder)
pprof.Lookup("goroutine").WriteTo(buf, 1)
e.logf("wgengine watchdog stacks:\n%s", buf.String())
// Collect the list of in-flight operations for debugging.
var (
b []byte
now = time.Now()
)
e.inFlightMu.Lock()
for k, t := range e.inFlight {
dur := now.Sub(t).Round(time.Millisecond)
b = fmt.Appendf(b, "in-flight[%d]: name=%s duration=%v start=%s\n", k.ctr, k.op, dur, t.Format(time.RFC3339Nano))
}
e.recordEvent(event)
e.inFlightMu.Unlock()
// Print everything as a single string to avoid log
// rate limits.
e.logf("wgengine watchdog in-flight:\n%s", b)
e.fatalf("wgengine: watchdog timeout on %s", event)
return nil
}
}
func (e *watchdogEngine) recordEvent(event watchdogEvent) {
if watchdogMetrics == nil {
return
}
mEvent, ok := watchdogMetrics[event]
if ok {
mEvent.Add(1)
}
mAny, ok := watchdogMetrics[Any]
if ok {
mAny.Add(1)
}
}
func (e *watchdogEngine) watchdog(event watchdogEvent, fn func()) {
e.watchdogErr(event, func() error {
fn()
return nil
})
}
func (e *watchdogEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config, dnsCfg *dns.Config) error {
return e.watchdogErr(Reconfig, func() error { return e.wrap.Reconfig(cfg, routerCfg, dnsCfg) })
}
func (e *watchdogEngine) ResetAndStop() (st *Status, err error) {
e.watchdog(ResetAndStop, func() {
st, err = e.wrap.ResetAndStop()
})
return st, err
}
func (e *watchdogEngine) GetFilter() *filter.Filter {
return e.wrap.GetFilter()
}
func (e *watchdogEngine) SetFilter(filt *filter.Filter) {
e.watchdog(SetFilter, func() { e.wrap.SetFilter(filt) })
}
func (e *watchdogEngine) GetJailedFilter() *filter.Filter {
return e.wrap.GetJailedFilter()
}
func (e *watchdogEngine) SetJailedFilter(filt *filter.Filter) {
e.watchdog(SetJailedFilter, func() { e.wrap.SetJailedFilter(filt) })
}
func (e *watchdogEngine) SetStatusCallback(cb StatusCallback) {
e.watchdog(SetStatusCallback, func() { e.wrap.SetStatusCallback(cb) })
}
func (e *watchdogEngine) UpdateStatus(sb *ipnstate.StatusBuilder) {
e.watchdog(UpdateStatus, func() { e.wrap.UpdateStatus(sb) })
}
func (e *watchdogEngine) RequestStatus() {
e.watchdog(RequestStatus, func() { e.wrap.RequestStatus() })
}
func (e *watchdogEngine) SetNetworkMap(nm *netmap.NetworkMap) {
e.watchdog(SetNetworkMap, func() { e.wrap.SetNetworkMap(nm) })
}
func (e *watchdogEngine) Ping(ip netip.Addr, pingType tailcfg.PingType, size int, cb func(*ipnstate.PingResult)) {
e.watchdog(Ping, func() { e.wrap.Ping(ip, pingType, size, cb) })
}
func (e *watchdogEngine) Close() {
e.watchdog(Close, e.wrap.Close)
}
func (e *watchdogEngine) PeerForIP(ip netip.Addr) (ret PeerForIP, ok bool) {
e.watchdog(PeerForIPEvent, func() { ret, ok = e.wrap.PeerForIP(ip) })
return ret, ok
}
func (e *watchdogEngine) Done() <-chan struct{} {
return e.wrap.Done()
}
func (e *watchdogEngine) InstallCaptureHook(cb packet.CaptureCallback) {
if !buildfeatures.HasCapture {
return
}
e.wrap.InstallCaptureHook(cb)
}
func (e *watchdogEngine) PeerByKey(pubKey key.NodePublic) (_ wgint.Peer, ok bool) {
return e.wrap.PeerByKey(pubKey)
}
func (e *watchdogEngine) PatchDiscoKey(pub key.NodePublic, disco key.DiscoPublic) {
// PatchDiscoKey mirrors the implementation of [controlclient.patchDiscoKeyer ].
// It is implemented here to avoid the dependency edge to controlclient, but must be kept
// in sync with the original implementation.
type patchDiscoKeyer interface {
PatchDiscoKey(key.NodePublic, key.DiscoPublic)
}
if n, ok := e.wrap.(patchDiscoKeyer); ok {
n.PatchDiscoKey(pub, disco)
}
}
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