Handle RTP Contributing Source Identifiers (CSRC)

RFC 3550 allows for parties to optionally specify a list of Contributing Source Identifiers
in the RTP header. Skip over them when looking for the RTP body.

src/switch_rtp.c

@@ -5322,16 +5322,20 @@ static switch_status_t read_rtp_packet(switch_rtp_t *rtp_session, switch_size_t
 
 
 		if (rtp_session->recv_msg.header.version == 2) {
+			if (rtp_session->recv_msg.header.cc > 0) { /* Contributing Source Identifiers (4 bytes = sizeof CSRC header)*/
+				rtp_session->recv_msg.ebody = RTP_BODY(rtp_session) + (rtp_session->recv_msg.header.cc * 4);
+			}
+
 			/* recalculate body length in case rtp extension used */
 			if (!rtp_session->flags[SWITCH_RTP_FLAG_PROXY_MEDIA] && !rtp_session->flags[SWITCH_RTP_FLAG_UDPTL] &&
 				rtp_session->recv_msg.header.version == 2 && rtp_session->recv_msg.header.x) { /* header extensions */
 				uint16_t length;
 			
-				rtp_session->recv_msg.ext = (switch_rtp_hdr_ext_t *) rtp_session->recv_msg.body;
+				rtp_session->recv_msg.ext = (switch_rtp_hdr_ext_t *) RTP_BODY(rtp_session);
 				length = ntohs((uint16_t)rtp_session->recv_msg.ext->length);
 		
 				if (length < SWITCH_RTP_MAX_BUF_LEN_WORDS) {
-					rtp_session->recv_msg.ebody = rtp_session->recv_msg.body + (length * 4) + 4;
+					rtp_session->recv_msg.ebody = (char *)rtp_session->recv_msg.ext + (length * 4) + 4;
 					if (*bytes > (length * 4 + 4)) {
 						*bytes -= (length * 4 + 4);
 					} else {