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cmd/cli: ensure goroutines that check DNS terminated

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So changes to DNS after ctrld stopped won't be reverted by the goroutine
itself. The problem happens rarely on darwin, because networksetup
command won't propagate config to /etc/resolv.conf if there is no
changes between multiple running.
This commit is contained in:
Cuong Manh Le
2024-08-07 22:55:31 +07:00
committed by Cuong Manh Le
parent 62a0ba8731
commit a007394f60
3 changed files with 42 additions and 20 deletions
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4
cmd/cli/cli.go
View File

@@ -1333,6 +1333,10 @@ func run(appCallback *AppCallback, stopCh chan struct{}) {
close(waitCh)
<-stopCh
// Wait goroutines which watches/manipulates DNS settings terminated,
// ensuring that changes to DNS since here won't be reverted.
p.dnsWg.Wait()
for _, f := range p.onStopped {
f()
}

53
cmd/cli/prog.go
View File

@@ -78,6 +78,7 @@ type prog struct {
csSetDnsDone chan struct{}
csSetDnsOk bool
dnsWatchDogOnce sync.Once
dnsWg sync.WaitGroup
cfg *ctrld.Config
localUpstreams []string
@@ -596,7 +597,11 @@ func (p *prog) setDNS() {
for i := range nameservers {
servers[i] = netip.MustParseAddr(nameservers[i])
}
go watchResolvConf(netIface, servers, setResolvConf)
p.dnsWg.Add(1)
go func() {
defer p.dnsWg.Done()
p.watchResolvConf(netIface, servers, setResolvConf)
}()
}
if allIfaces {
withEachPhysicalInterfaces(netIface.Name, "set DNS", func(i *net.Interface) error {
@@ -604,7 +609,11 @@ func (p *prog) setDNS() {
})
}
if p.dnsWatchdogEnabled() {
go p.dnsWatchdog(netIface, nameservers, allIfaces)
p.dnsWg.Add(1)
go func() {
defer p.dnsWg.Done()
p.dnsWatchdog(netIface, nameservers, allIfaces)
}()
}
}
@@ -639,24 +648,30 @@ func (p *prog) dnsWatchdog(iface *net.Interface, nameservers []string, allIfaces
slices.Sort(ns)
ticker := time.NewTicker(p.dnsWatchdogDuration())
logger := mainLog.Load().With().Str("iface", iface.Name).Logger()
for range ticker.C {
if dnsChanged(iface, ns) {
logger.Debug().Msg("DNS settings were changed, re-applying settings")
if err := setDNS(iface, ns); err != nil {
mainLog.Load().Error().Err(err).Str("iface", iface.Name).Msgf("could not re-apply DNS settings")
}
}
if allIfaces {
withEachPhysicalInterfaces(iface.Name, "re-applying DNS", func(i *net.Interface) error {
if dnsChanged(i, ns) {
if err := setDnsIgnoreUnusableInterface(i, nameservers); err != nil {
mainLog.Load().Error().Err(err).Str("iface", i.Name).Msgf("could not re-apply DNS settings")
} else {
mainLog.Load().Debug().Msgf("re-applying DNS for interface %q successfully", i.Name)
}
for {
select {
case <-p.stopCh:
mainLog.Load().Debug().Msg("stop dns watchdog")
return
case <-ticker.C:
if dnsChanged(iface, ns) {
logger.Debug().Msg("DNS settings were changed, re-applying settings")
if err := setDNS(iface, ns); err != nil {
mainLog.Load().Error().Err(err).Str("iface", iface.Name).Msgf("could not re-apply DNS settings")
}
return nil
})
}
if allIfaces {
withEachPhysicalInterfaces(iface.Name, "re-applying DNS", func(i *net.Interface) error {
if dnsChanged(i, ns) {
if err := setDnsIgnoreUnusableInterface(i, nameservers); err != nil {
mainLog.Load().Error().Err(err).Str("iface", i.Name).Msgf("could not re-apply DNS settings")
} else {
mainLog.Load().Debug().Msgf("re-applying DNS for interface %q successfully", i.Name)
}
}
return nil
})
}
}
}
})

5
cmd/cli/resolvconf.go
View File

@@ -10,7 +10,7 @@ import (
// watchResolvConf watches any changes to /etc/resolv.conf file,
// and reverting to the original config set by ctrld.
func watchResolvConf(iface *net.Interface, ns []netip.Addr, setDnsFn func(iface *net.Interface, ns []netip.Addr) error) {
func (p *prog) watchResolvConf(iface *net.Interface, ns []netip.Addr, setDnsFn func(iface *net.Interface, ns []netip.Addr) error) {
resolvConfPath := "/etc/resolv.conf"
// Evaluating symbolics link to watch the target file that /etc/resolv.conf point to.
if rp, _ := filepath.EvalSymlinks(resolvConfPath); rp != "" {
@@ -34,6 +34,9 @@ func watchResolvConf(iface *net.Interface, ns []netip.Addr, setDnsFn func(iface
for {
select {
case <-p.stopCh:
mainLog.Load().Debug().Msgf("stopping watcher for %s", resolvConfPath)
return
case event, ok := <-watcher.Events:
if !ok {
return