tailscale/wgengine/watchdog.go

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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package wgengine
import (
"log"
"os"
"runtime/pprof"
"strconv"
"strings"
"time"
"inet.af/netaddr"
"tailscale.com/ipn/ipnstate"
"tailscale.com/net/dns"
"tailscale.com/tailcfg"
"tailscale.com/types/netmap"
"tailscale.com/wgengine/filter"
"tailscale.com/wgengine/monitor"
"tailscale.com/wgengine/router"
"tailscale.com/wgengine/wgcfg"
)
// 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 v, _ := strconv.ParseBool(os.Getenv("TS_DEBUG_DISABLE_WATCHDOG")); v {
return e
}
return &watchdogEngine{
wrap: e,
logf: log.Printf,
fatalf: log.Fatalf,
maxWait: 45 * time.Second,
}
}
type watchdogEngine struct {
wrap Engine
logf func(format string, args ...interface{})
fatalf func(format string, args ...interface{})
maxWait time.Duration
}
func (e *watchdogEngine) watchdogErr(name string, fn func() error) error {
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())
e.fatalf("wgengine: watchdog timeout on %s", name)
return nil
}
}
func (e *watchdogEngine) watchdog(name string, fn func()) {
e.watchdogErr(name, func() error {
fn()
return nil
})
}
func (e *watchdogEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config) error {
return e.watchdogErr("Reconfig", func() error { return e.wrap.Reconfig(cfg, routerCfg) })
}
func (e *watchdogEngine) GetLinkMonitor() *monitor.Mon {
return e.wrap.GetLinkMonitor()
}
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) SetDNSMap(dm *dns.Map) {
e.watchdog("SetDNSMap", func() { e.wrap.SetDNSMap(dm) })
}
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) SetNetInfoCallback(cb NetInfoCallback) {
e.watchdog("SetNetInfoCallback", func() { e.wrap.SetNetInfoCallback(cb) })
}
func (e *watchdogEngine) RequestStatus() {
e.watchdog("RequestStatus", func() { e.wrap.RequestStatus() })
}
func (e *watchdogEngine) LinkChange(isExpensive bool) {
e.watchdog("LinkChange", func() { e.wrap.LinkChange(isExpensive) })
}
func (e *watchdogEngine) SetDERPMap(m *tailcfg.DERPMap) {
e.watchdog("SetDERPMap", func() { e.wrap.SetDERPMap(m) })
}
func (e *watchdogEngine) SetNetworkMap(nm *netmap.NetworkMap) {
e.watchdog("SetNetworkMap", func() { e.wrap.SetNetworkMap(nm) })
}
func (e *watchdogEngine) AddNetworkMapCallback(callback NetworkMapCallback) func() {
var fn func()
e.watchdog("AddNetworkMapCallback", func() { fn = e.wrap.AddNetworkMapCallback(callback) })
return func() { e.watchdog("RemoveNetworkMapCallback", fn) }
}
func (e *watchdogEngine) DiscoPublicKey() (k tailcfg.DiscoKey) {
e.watchdog("DiscoPublicKey", func() { k = e.wrap.DiscoPublicKey() })
return k
}
func (e *watchdogEngine) Ping(ip netaddr.IP, useTSMP bool, cb func(*ipnstate.PingResult)) {
e.watchdog("Ping", func() { e.wrap.Ping(ip, useTSMP, cb) })
}
func (e *watchdogEngine) RegisterIPPortIdentity(ipp netaddr.IPPort, tsIP netaddr.IP) {
e.watchdog("RegisterIPPortIdentity", func() { e.wrap.RegisterIPPortIdentity(ipp, tsIP) })
}
func (e *watchdogEngine) UnregisterIPPortIdentity(ipp netaddr.IPPort) {
e.watchdog("UnregisterIPPortIdentity", func() { e.wrap.UnregisterIPPortIdentity(ipp) })
}
func (e *watchdogEngine) WhoIsIPPort(ipp netaddr.IPPort) (tsIP netaddr.IP, ok bool) {
e.watchdog("UnregisterIPPortIdentity", func() { tsIP, ok = e.wrap.WhoIsIPPort(ipp) })
return tsIP, ok
}
func (e *watchdogEngine) Close() {
e.watchdog("Close", e.wrap.Close)
}
func (e *watchdogEngine) Wait() {
e.wrap.Wait()
}