tailscale/wgengine/watchdog.go
Brad Fitzpatrick 9b07517f18 wgengine: add Engine.SetLinkChangeCallback
Start of making the IPN state machine react to link changes and down
its DNS & routes if necessary to unblock proxy resolution (e.g. for
transitioning from public to corp networks where the corp network has
mandatory proxies and WPAD PAC files that can't be resolved while
using the DNS/routes configured previously)

This change should be a no-op. Just some callback plumbing.
2020-08-27 21:25:17 -07:00

126 lines
3.7 KiB
Go

// 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"
"github.com/tailscale/wireguard-go/wgcfg"
"inet.af/netaddr"
"tailscale.com/control/controlclient"
"tailscale.com/ipn/ipnstate"
"tailscale.com/net/interfaces"
"tailscale.com/tailcfg"
"tailscale.com/wgengine/filter"
"tailscale.com/wgengine/router"
"tailscale.com/wgengine/tsdns"
)
// 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) GetFilter() *filter.Filter {
var x *filter.Filter
e.watchdog("GetFilter", func() { x = e.wrap.GetFilter() })
return x
}
func (e *watchdogEngine) SetFilter(filt *filter.Filter) {
e.watchdog("SetFilter", func() { e.wrap.SetFilter(filt) })
}
func (e *watchdogEngine) SetDNSMap(dm *tsdns.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) SetLinkChangeCallback(cb func(major bool, newState *interfaces.State)) {
e.watchdog("SetLinkChangeCallback", func() { e.wrap.SetLinkChangeCallback(cb) })
}
func (e *watchdogEngine) SetDERPMap(m *tailcfg.DERPMap) {
e.watchdog("SetDERPMap", func() { e.wrap.SetDERPMap(m) })
}
func (e *watchdogEngine) SetNetworkMap(nm *controlclient.NetworkMap) {
e.watchdog("SetNetworkMap", func() { e.wrap.SetNetworkMap(nm) })
}
func (e *watchdogEngine) DiscoPublicKey() (k tailcfg.DiscoKey) {
e.watchdog("DiscoPublicKey", func() { k = e.wrap.DiscoPublicKey() })
return k
}
func (e *watchdogEngine) Ping(ip netaddr.IP, cb func(*ipnstate.PingResult)) {
e.watchdog("Ping", func() { e.wrap.Ping(ip, cb) })
}
func (e *watchdogEngine) Close() {
e.watchdog("Close", e.wrap.Close)
}
func (e *watchdogEngine) Wait() {
e.wrap.Wait()
}