Merge pull request #5 from fzu-huang/dev/support-spec-src-ip

support DAD arping

arp_datagram.go

@@ -77,6 +77,11 @@ func (datagram arpDatagram) IsResponseOf(request arpDatagram) bool {
 		bytes.Equal(request.tpa, datagram.spa)
 }
 
+func (datagram arpDatagram) IsDuplicateRequestOf(request arpDatagram) bool {
+	return datagram.oper == requestOper && bytes.Equal(request.spa, datagram.tpa) &&
+		bytes.Equal(request.tpa, datagram.tpa)
+}
+
 func parseArpDatagram(buffer []byte) arpDatagram {
 	var datagram arpDatagram
 

arping.go

@@ -146,6 +146,17 @@ func PingOverIface(dstIP, srcIP net.IP, iface net.Interface) (net.HardwareAddr,
 					return
 				}
 
+				if srcIP.Equal(net.IPv4zero) || srcIP.Equal(net.IPv6zero) {
+					// if arping with src IP as IPv4zero, we expect no response but request from dst IP
+					if response.IsDuplicateRequestOf(request) {
+						duration := receiveTime.Sub(sendTime)
+						verboseLog.Printf("process received arp: srcIP: '%s', srcMac: '%s'\n",
+							response.SenderIP(), response.SenderMac())
+						pingResultChan <- PingResult{response.SenderMac(), duration, err}
+						return
+					}
+				}
+
 				if response.IsResponseOf(request) {
 					duration := receiveTime.Sub(sendTime)
 					verboseLog.Printf("process received arp: srcIP: '%s', srcMac: '%s'\n",