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Code Issues Releases Wiki Activity

Avoid unnecessary dhcp message

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This commit is contained in:
wweir
2019-03-20 08:45:37 +08:00
parent 45ca063a7e
commit eb8080df18
2 changed files with 32 additions and 17 deletions
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dns/dhcp.go
+2 -2
View File
@@ -29,11 +29,11 @@ func GetDefaultDNSServer() (string, error) {
var conn net.PacketConn
if runtime.GOOS == "windows" {
if conn, err = reuseport.ListenPacket("udp", iface.IP.String()+":68"); err != nil {
if conn, err = reuseport.ListenPacket("udp4", iface.IP.String()+":68"); err != nil {
return "", errors.Wrap(err, "listen dhcp")
}
} else {
if conn, err = reuseport.ListenPacket("udp", "0.0.0.0:68"); err != nil {
if conn, err = reuseport.ListenPacket("udp4", "0.0.0.0:68"); err != nil {
return "", errors.Wrap(err, "listen dhcp")
}
}
dns/dns.go
+30 -15
View File
@@ -24,19 +24,7 @@ func StartDNS(dnsServer, listenIP string, suggestCh chan<- string, suggestLevel
if dnsServer != "" {
dnsServer = net.JoinHostPort(dnsServer, "53")
} else {
go func() {
for {
<-dhcpCh
host, err := GetDefaultDNSServer()
if err != nil {
glog.Errorln(err)
continue
}
// atomic action
dnsServer = net.JoinHostPort(host, "53")
glog.Infoln("set dns server to", host)
}
}()
go dynamicSetUpstreamDNS(listenIP, &dnsServer, dhcpCh)
dhcpCh <- struct{}{}
}
@@ -64,6 +52,33 @@ func StartDNS(dnsServer, listenIP string, suggestCh chan<- string, suggestLevel
glog.Fatalln(server.ListenAndServe())
}
func dynamicSetUpstreamDNS(listenIP string, dnsServer *string, dhcpCh <-chan struct{}) {
addr, _ := dns.ReverseAddr(listenIP)
msg := &dns.Msg{
MsgHdr: dns.MsgHdr{
Id: dns.Id(),
RecursionDesired: false,
},
Question: []dns.Question{{addr, dns.TypeA, dns.ClassINET}},
}
for {
<-dhcpCh
if _, err := dns.Exchange(msg, *dnsServer); err == nil {
continue
}
host, err := GetDefaultDNSServer()
if err != nil {
glog.Errorln(err)
continue
}
// atomic action
*dnsServer = net.JoinHostPort(host, "53")
glog.Infoln("set dns server to", host)
}
}
func matchAndServe(w dns.ResponseWriter, r *dns.Msg, domain, listenIP, dnsServer string,
dhcpCh chan struct{}, ipNet net.IP, suggest *intelliSuggest) {
@@ -85,10 +100,10 @@ func matchAndServe(w dns.ResponseWriter, r *dns.Msg, domain, listenIP, dnsServer
default:
}
}
glog.V(1).Infof("get dns of %s fail: %s", domain, err)
glog.V(1).Infof("get dns of %s from %s fail: %s", domain, dnsServer, err)
return
} else if msg == nil { // expose any response except nil
glog.V(1).Infof("get dns of %s return empty", domain)
glog.V(1).Infof("get dns of %s from %s return empty", domain, dnsServer)
return
}