#226 Update to allow for use of rtcp-mux where RTP is multiplexed with RTCP

Makefile

@@ -15,4 +15,4 @@ test:
 
 .PHONY: clean
 clean:
-	rm -fr $(NAME)
+	rm -fr $(NAME)

decoder/correlator.go

@@ -123,8 +123,10 @@ func extractCID(srcIP net.IP, srcPort uint16, dstIP net.IP, dstPort uint16, payl
 		posLineEnd = 0    // end of line, position of \n or end of content.
 		session    = true // in session or multimedia?
 		sessionIP  []byte // IP found in session connection.
+		rtpPort    []byte // port for RTP.
 		rtcpIP     []byte // IP for RTCP.
 		rtcpPort   []byte // port for RTCP.
+		rtcpMux    = false
 	)
 sdpLoop:
 	for posLine = 0; posLine < len(content); posLine = posLineEnd + 1 {
@@ -207,6 +209,11 @@ sdpLoop:
 			}
 			rtcpPort = []byte(strconv.Itoa(rtpPortNb + 1))
 		case 'a':
+			// If rtcp-mux is indicated, RTCP can appear on the RTP port
+			if bytes.HasPrefix(line, []byte("a=rtcp-mux")) {
+				rtcpMux = true
+				continue sdpLoop
+			}
 			// We are only interested in a=rtcp.
 			if !bytes.HasPrefix(line, []byte("a=rtcp:")) {
 				continue sdpLoop
@@ -245,6 +252,10 @@ sdpLoop:
 	if len(rtcpIP) > 0 && len(rtcpPort) > 0 {
 		cacheCID(srcIPb, rtcpIP, rtcpPort, callID)
 	}
+	// If rtcp-mux is in use add an entry for the rtp port
+	if rtcpMux && len(rtcpIP)>0 && len(rtpPort)>0 && string(rtpPort)!=string(rtcpPort) {
+		cacheCID(srcIPb, rtcpIP, rtpPort, callID)
+	}
 }
 
 // correlateRTCP will try to correlate RTCP data with SIP messages.

decoder/decoder.go

@@ -914,24 +914,17 @@ func (d *Decoder) processTransport(foundLayerTypes *[]gopacket.LayerType, udp *l
 				}
 			}
 			if config.Cfg.Mode != "SIP" {
-				if (udp.Payload[0]&0xc0)>>6 == 2 {
-					if (udp.Payload[1] == 200 || udp.Payload[1] == 201 || udp.Payload[1] == 207) && udp.SrcPort%2 != 0 && udp.DstPort%2 != 0 {
-						pkt.Payload, pkt.CID = correlateRTCP(pkt.SrcIP, pkt.SrcPort, pkt.DstIP, pkt.DstPort, udp.Payload)
-						if pkt.Payload != nil {
-							pkt.ProtoType = 5
-							atomic.AddUint64(&d.rtcpCount, 1)
-							PacketQueue <- pkt
-							return
-						}
-						atomic.AddUint64(&d.rtcpFailCount, 1)
-						return
-					} else if udp.SrcPort%2 == 0 && udp.DstPort%2 == 0 {
-						if config.Cfg.Mode == "SIPRTP" {
-							logp.Debug("rtp", "\n%v", protos.NewRTP(udp.Payload))
-						}
-						pkt.Payload = nil
-						return
-					}
+				if (udp.Payload[0]&0xc0)>>6 == 2 &&
+				    (udp.Payload[1] == 200 || udp.Payload[1] == 201 || udp.Payload[1] == 207) {
+					    pkt.Payload, pkt.CID = correlateRTCP(pkt.SrcIP, pkt.SrcPort, pkt.DstIP, pkt.DstPort, udp.Payload)
+					    if pkt.Payload != nil {
+						    pkt.ProtoType = 5
+						    atomic.AddUint64(&d.rtcpCount, 1)
+						    PacketQueue <- pkt
+						    return
+					    }
+					    atomic.AddUint64(&d.rtcpFailCount, 1)
+					    return
 				}
 				extractCID(pkt.SrcIP, pkt.SrcPort, pkt.DstIP, pkt.DstPort, pkt.Payload)
 			}