Fix loopback for non local IP's

buger · Jul 5, 2016 · 1ed8691 · 1ed8691
1 parent f17f513
commit 1ed8691
Showing 1 changed file with 63 additions and 11 deletions.
diff --git a/raw_socket_listener/listener.go b/raw_socket_listener/listener.go
@@ -254,14 +254,36 @@ func (e *DeviceNotFoundError) Error() string {
 	return msg
 }
 
+func isLoopback(device pcap.Interface) bool {
+	if len(device.Addresses) == 0 {
+		return false
+	}
+
+	switch device.Addresses[0].IP.String() {
+	case "127.0.0.1", "::1":
+		return true
+	}
+
+	return false
+}
+
+func listenAllInterfaces(addr string) bool {
+	switch addr {
+	case "", "0.0.0.0", "[::]", "::":
+		return true
+	default:
+		return false
+	}
+}
+
 func findPcapDevices(addr string) (interfaces []pcap.Interface, err error) {
 	devices, err := pcap.FindAllDevs()
 	if err != nil {
 		log.Fatal(err)
 	}
 
 	for _, device := range devices {
-		if (addr == "" || addr == "0.0.0.0" || addr == "[::]" || addr == "::") && len(device.Addresses) > 0 {
+		if listenAllInterfaces(addr) && len(device.Addresses) > 0 || isLoopback(device) {
 			interfaces = append(interfaces, device)
 			continue
 		}
@@ -309,12 +331,26 @@ func (t *Listener) readPcap() {
 			t.pcapHandles = append(t.pcapHandles, handle)
 
 			var bpfDstHost, bpfSrcHost string
-			for i, addr := range device.Addresses {
-				bpfDstHost += "dst host " + addr.IP.String()
-				bpfSrcHost += "src host " + addr.IP.String()
-				if i != len(device.Addresses)-1 {
-					bpfDstHost += " or "
-					bpfSrcHost += " or "
+			var loopback = isLoopback(device)
+
+			if loopback {
+				var allAddr []string
+				for _, dc := range devices {
+					for _, addr := range dc.Addresses {
+						allAddr = append(allAddr, "(dst host " + addr.IP.String() + " and src host " + addr.IP.String() + ")")
+					}
+				}
+
+				bpfDstHost = strings.Join(allAddr, " or ")
+				bpfSrcHost = bpfDstHost
+			} else {
+				for i, addr := range device.Addresses {
+					bpfDstHost += "dst host " + addr.IP.String()
+					bpfSrcHost += "src host " + addr.IP.String()
+					if i != len(device.Addresses)-1 {
+						bpfDstHost += " or "
+						bpfSrcHost += " or "
+					}
 				}
 			}
 
@@ -439,10 +475,26 @@ func (t *Listener) readPcap() {
 						}
 
 						addrMatched := false
-						for _, a := range device.Addresses {
-							if a.IP.Equal(net.IP(addrCheck)) {
-								addrMatched = true
-								break
+
+						if loopback {
+							for _, dc := range devices {
+								if addrMatched {
+									break
+								}
+								for _, a := range dc.Addresses {
+									if a.IP.Equal(net.IP(addrCheck)) {
+										addrMatched = true
+										break
+									}
+								}
+							}
+							addrMatched = true
+						} else {
+							for _, a := range device.Addresses {
+								if a.IP.Equal(net.IP(addrCheck)) {
+									addrMatched = true
+									break
+								}
 							}
 						}