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Add error to function return

pull/6/head
Jiangtian Li 2017-05-10 23:36:08 -07:00
parent 33d878bc5a
commit 1760767047
1 changed files with 57 additions and 34 deletions
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91
pkg/proxy/winuserspace/proxysocket.go
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@ -267,10 +267,9 @@ func isDNSService(portName string) bool {
return portName == dnsPortName
}
func appendDNSSuffix(msg *dns.Msg, buffer []byte, length int, dnsSuffix string) int {
func appendDNSSuffix(msg *dns.Msg, buffer []byte, length int, dnsSuffix string) (int, error) {
if msg == nil || len(msg.Question) == 0 {
glog.Warning("DNS message parameter is invalid.")
return length
return length, fmt.Errorf("DNS message parameter is invalid")
}
// Save the original name since it will be reused for next iteration
@ -283,25 +282,23 @@ func appendDNSSuffix(msg *dns.Msg, buffer []byte, length int, dnsSuffix string)
if err != nil {
glog.Warning("Unable to pack DNS packet. Error is: %v", err)
return length
return length, err
}
if &buffer[0] != &mbuf[0] {
glog.Warning("Buffer is too small in packing DNS packet.")
return length
return length, fmt.Errorf("Buffer is too small in packing DNS packet")
}
return len(mbuf)
return len(mbuf), nil
}
func recoverDNSQuestion(origName string, msg *dns.Msg, buffer []byte, length int) int {
func recoverDNSQuestion(origName string, msg *dns.Msg, buffer []byte, length int) (int, error) {
if msg == nil || len(msg.Question) == 0 {
glog.Warning("DNS message parameter is invalid.")
return length
return length, fmt.Errorf("DNS message parameter is invalid")
}
if origName == msg.Question[0].Name {
return length
return length, nil
}
msg.Question[0].Name = origName
@ -312,15 +309,14 @@ func recoverDNSQuestion(origName string, msg *dns.Msg, buffer []byte, length int
if err != nil {
glog.Warning("Unable to pack DNS packet. Error is: %v", err)
return length
return length, err
}
if &buffer[0] != &mbuf[0] {
glog.Warning("Buffer is too small in packing DNS packet.")
return length
return length, fmt.Errorf("Buffer is too small in packing DNS packet")
}
return len(mbuf)
return len(mbuf), nil
}
func processUnpackedDNSQueryPacket(
@ -354,7 +350,11 @@ func processUnpackedDNSQueryPacket(
return length
}
length = appendDNSSuffix(msg, buffer, length, dnsSearch[index])
length, err := appendDNSSuffix(msg, buffer, length, dnsSearch[index])
if err != nil {
glog.Errorf("Append DNS suffix failed: %v", err)
}
return length
}
@ -369,6 +369,7 @@ func processUnpackedDNSResponsePacket(
length int,
dnsSearch []string) (bool, int) {
var drop bool
var err error
if dnsSearch == nil || len(dnsSearch) == 0 {
glog.V(1).Infof("DNS search list is not initialized and is empty.")
return drop, length
@ -384,16 +385,23 @@ func processUnpackedDNSResponsePacket(
// If the reponse has failure and iteration through the search list has not
// reached the end, retry on behalf of the client using the original query message
drop = true
length = appendDNSSuffix(state.msg, buffer, length, dnsSearch[index])
length, err = appendDNSSuffix(state.msg, buffer, length, dnsSearch[index])
if err != nil {
glog.Errorf("Append DNS suffix failed: %v", err)
}
_, err := svrConn.Write(buffer[0:length])
_, err = svrConn.Write(buffer[0:length])
if err != nil {
if !logTimeout(err) {
glog.Errorf("Write failed: %v", err)
}
}
} else {
length = recoverDNSQuestion(state.msg.Question[0].Name, msg, buffer, length)
length, err = recoverDNSQuestion(state.msg.Question[0].Name, msg, buffer, length)
if err != nil {
glog.Errorf("Recover DNS question failed: %v", err)
}
dnsClients.mu.Lock()
delete(dnsClients.clients, dnsClientQuery{host, dnsQType})
dnsClients.mu.Unlock()
@ -403,30 +411,34 @@ func processUnpackedDNSResponsePacket(
return drop, length
}
func processDNSQueryPacket(dnsClients *dnsClientCache, cliAddr net.Addr, buffer []byte, length int, dnsSearch []string) int {
func processDNSQueryPacket(
dnsClients *dnsClientCache,
cliAddr net.Addr,
buffer []byte,
length int,
dnsSearch []string) (int, error) {
msg := &dns.Msg{}
if err := msg.Unpack(buffer[:length]); err != nil {
glog.Warning("Unable to unpack DNS packet. Error is: %v", err)
return length
return length, err
}
// Query - Response bit that specifies whether this message is a query (0) or a response (1).
if msg.MsgHdr.Response == true {
glog.Warning("DNS packet should be a query message.")
return length
return length, fmt.Errorf("DNS packet should be a query message")
}
// QDCOUNT
if len(msg.Question) != 1 {
glog.V(1).Infof("Number of entries in the question section of the DNS packet is: %d", len(msg.Question))
glog.V(1).Infof("DNS suffix appending does not support more than one question.")
return length
return length, nil
}
// ANCOUNT, NSCOUNT, ARCOUNT
if len(msg.Answer) != 0 || len(msg.Ns) != 0 || len(msg.Extra) != 0 {
glog.V(1).Infof("DNS packet contains more than question section.")
return length
return length, nil
}
dnsQType := msg.Question[0].Qtype
@ -441,27 +453,32 @@ func processDNSQueryPacket(dnsClients *dnsClientCache, cliAddr net.Addr, buffer
length = processUnpackedDNSQueryPacket(dnsClients, msg, host, dnsQType, buffer, length, dnsSearch)
}
return length
return length, nil
}
func processDNSResponsePacket(svrConn net.Conn, dnsClients *dnsClientCache, cliAddr net.Addr, buffer []byte, length int, dnsSearch []string) (bool, int) {
func processDNSResponsePacket(
svrConn net.Conn,
dnsClients *dnsClientCache,
cliAddr net.Addr,
buffer []byte,
length int,
dnsSearch []string) (bool, int, error) {
var drop bool
msg := &dns.Msg{}
if err := msg.Unpack(buffer[:length]); err != nil {
glog.Warning("Unable to unpack DNS packet. Error is: %v", err)
return drop, length
return drop, length, err
}
// Query - Response bit that specifies whether this message is a query (0) or a response (1).
if msg.MsgHdr.Response == false {
glog.Warning("DNS packet should be a response message.")
return drop, length
return drop, length, fmt.Errorf("DNS packet should be a response message")
}
// QDCOUNT
if len(msg.Question) != 1 {
glog.V(1).Infof("Number of entries in the reponse section of the DNS packet is: %d", len(msg.Answer))
return drop, length
return drop, length, nil
}
dnsQType := msg.Question[0].Qtype
@ -476,7 +493,7 @@ func processDNSResponsePacket(svrConn net.Conn, dnsClients *dnsClientCache, cliA
drop, length = processUnpackedDNSResponsePacket(svrConn, dnsClients, msg, msg.MsgHdr.Rcode, host, dnsQType, buffer, length, dnsSearch)
}
return drop, length
return drop, length, nil
}
func (udp *udpProxySocket) ProxyLoop(service ServicePortPortalName, myInfo *serviceInfo, proxier *Proxier) {
@ -516,7 +533,10 @@ func (udp *udpProxySocket) ProxyLoop(service ServicePortPortalName, myInfo *serv
// If this is DNS query packet
if isDNSService(service.Port) {
n = processDNSQueryPacket(myInfo.dnsClients, cliAddr, buffer[:], n, dnsSearch)
n, err = processDNSQueryPacket(myInfo.dnsClients, cliAddr, buffer[:], n, dnsSearch)
if err != nil {
glog.Errorf("Process DNS query packet failed: %v", err)
}
}
// If this is a client we know already, reuse the connection and goroutine.
@ -585,7 +605,10 @@ func (udp *udpProxySocket) proxyClient(cliAddr net.Addr, svrConn net.Conn, activ
drop := false
if isDNSService(service.Port) {
drop, n = processDNSResponsePacket(svrConn, dnsClients, cliAddr, buffer[:], n, dnsSearch)
drop, n, err = processDNSResponsePacket(svrConn, dnsClients, cliAddr, buffer[:], n, dnsSearch)
if err != nil {
glog.Errorf("Process DNS response packet failed: %v", err)
}
}
if !drop {