Merge pull request #1428 from meetecho/fix-rtcp-report

Fix SSRCs and RTP timestamps in incoming RTCP reports

Author: lminiero

ice.c

@@ -2596,11 +2596,12 @@ static void janus_ice_cb_nice_recv(NiceAgent *agent, guint stream_id, guint comp
 							video = 0;
 						} else if(rtcp_ssrc == stream->video_ssrc) {
 							video = 1;
-						} else {
+						} else if(janus_rtcp_has_fir(buf, len) || janus_rtcp_has_pli(buf, len) || janus_rtcp_get_remb(buf, len)) {
 							/* Mh, no SR or RR? Try checking if there's any FIR, PLI or REMB */
-							if(janus_rtcp_has_fir(buf, len) || janus_rtcp_has_pli(buf, len) || janus_rtcp_get_remb(buf, len)) {
-								video = 1;
-							}
+							video = 1;
+						} else {
+							JANUS_LOG(LOG_WARN,"[%"SCNu64"] Dropping RTCP packet with unknown SSRC (%"SCNu32")\n", handle->handle_id, rtcp_ssrc);
+							return;
 						}
 						JANUS_LOG(LOG_HUGE, "[%"SCNu64"] Incoming RTCP, bundling: this is %s (local SSRC: video=%"SCNu32", audio=%"SCNu32", got %"SCNu32")\n",
 							handle->handle_id, video ? "video" : "audio", stream->video_ssrc, stream->audio_ssrc, rtcp_ssrc);
@@ -2618,6 +2619,9 @@ static void janus_ice_cb_nice_recv(NiceAgent *agent, guint stream_id, guint comp
 						} else if(stream->video_ssrc_peer[2] && rtcp_ssrc == stream->video_ssrc_peer[2]) {
 							video = 1;
 							vindex = 2;
+						} else {
+							JANUS_LOG(LOG_WARN,"[%"SCNu64"] Dropping RTCP packet with unknown SSRC (%"SCNu32")\n", handle->handle_id, rtcp_ssrc);
+							return;
 						}
 						JANUS_LOG(LOG_HUGE, "[%"SCNu64"] Incoming RTCP, bundling: this is %s (remote SSRC: video=%"SCNu32" #%d, audio=%"SCNu32", got %"SCNu32")\n",
 							handle->handle_id, video ? "video" : "audio", stream->video_ssrc_peer[vindex], vindex, stream->audio_ssrc_peer, rtcp_ssrc);
@@ -2715,6 +2719,18 @@ static void janus_ice_cb_nice_recv(NiceAgent *agent, guint stream_id, guint comp
 					component->retransmit_log_ts = now;
 				}
 
+				/* Fix packet data for RTCP SR and RTCP RR */
+				janus_rtp_switching_context *rtp_ctx = video ? &stream->rtp_ctx[vindex] : &stream->rtp_ctx[0];
+				uint32_t ssrc_peer = video ? stream->video_ssrc_peer_orig[vindex] : stream->audio_ssrc_peer_orig;
+				uint32_t ssrc_local = video ? stream->video_ssrc : stream->audio_ssrc;
+				uint32_t ssrc_expected = video ? rtp_ctx->v_last_ssrc : rtp_ctx->a_last_ssrc;
+				if (janus_rtcp_fix_report_data(buf, buflen, rtp_ctx, ssrc_peer, ssrc_local, ssrc_expected, video) < 0) {
+					/* Drop packet in case of parsing error or SSRC different from the one expected. */
+					/* This might happen at the very beginning of the communication or early after */
+					/* a re-negotation has been concluded. */
+					return;
+				}
+
 				janus_plugin *plugin = (janus_plugin *)handle->app;
 				if(plugin && plugin->incoming_rtcp && handle->app_handle &&
 						!g_atomic_int_get(&handle->app_handle->stopped) &&

rtcp.c

@@ -692,6 +692,74 @@ gboolean janus_rtcp_parse_lost_info(char *packet, int len, uint32_t *lost, int *
 	return FALSE;
 }
 
+int janus_rtcp_fix_report_data(char *packet, int len, janus_rtp_switching_context *rtp_ctx, uint32_t ssrc_peer, uint32_t ssrc_local, uint32_t ssrc_expected, gboolean video) {
+	if(packet == NULL || len <= 0)
+		return -1;
+	/* Parse RTCP compound packet */
+	janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
+	if(rtcp->version != 2)
+		return -2;
+	int pno = 0, total = len, status = 0;
+	while(rtcp) {
+		pno++;
+		switch(rtcp->type) {
+			case RTCP_RR: {
+				janus_rtcp_rr *rr = (janus_rtcp_rr *)rtcp;
+				uint32_t recv_ssrc = ntohl(rr->ssrc);
+				if (recv_ssrc != ssrc_expected) {
+					JANUS_LOG(LOG_WARN,"Incoming RTCP RR SSRC (%"SCNu32") does not match the expected one (%"SCNu32") video=%d\n", recv_ssrc, ssrc_expected, video);
+					return -3;
+				}
+				rr->ssrc = htonl(ssrc_peer);
+				status++;
+				if (rr->header.rc > 0) {
+					rr->rb[0].ssrc = htonl(ssrc_local);
+					status++;
+					/* FIXME we need to fix the extended highest sequence number received */
+					/* FIXME we need to fix the cumulative number of packets lost */
+					break;
+				}
+				break;
+			}
+			case RTCP_SR: {
+				janus_rtcp_sr *sr = (janus_rtcp_sr *)rtcp;
+				uint32_t recv_ssrc = ntohl(sr->ssrc);
+				if (recv_ssrc != ssrc_expected) {
+					JANUS_LOG(LOG_WARN,"Incoming RTCP SR SSRC (%"SCNu32") does not match the expected one (%"SCNu32") video=%d\n", recv_ssrc, ssrc_expected, video);
+					return -3;
+				}
+				sr->ssrc = htonl(ssrc_peer);
+				/* FIXME we need to fix the sender's packet count */
+				/* FIXME we need to fix the sender's octet count */
+				uint32_t sr_ts = ntohl(sr->si.rtp_ts);
+				uint32_t fix_ts = video ? (sr_ts - rtp_ctx->v_base_ts) + rtp_ctx->v_base_ts_prev :
+						(sr_ts - rtp_ctx->a_base_ts) + rtp_ctx->a_base_ts_prev;
+				sr->si.rtp_ts = htonl(fix_ts);
+				status++;
+				if (sr->header.rc > 0) {
+					sr->rb[0].ssrc = htonl(ssrc_local);
+					status++;
+					/* FIXME we need to fix the extended highest sequence number received */
+					/* FIXME we need to fix the cumulative number of packets lost */
+					break;
+				}
+				break;
+			}
+			default:
+				break;
+		}
+		/* Is this a compound packet? */
+		int length = ntohs(rtcp->length);
+		if(length == 0)
+			break;
+		total -= length*4+4;
+		if(total <= 0)
+			break;
+		rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
+	}
+	return status;
+}
+
 gboolean janus_rtcp_has_bye(char *packet, int len) {
 	/* Parse RTCP compound packet */
 	janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;

rtcp.h

@@ -338,6 +338,17 @@ guint32 janus_rtcp_get_receiver_ssrc(char *packet, int len);
  * @returns 0 in case of success, -1 on errors */
 int janus_rtcp_parse(janus_rtcp_context *ctx, char *packet, int len);
 
+/*! \brief Method to fix incoming RTCP SR and RR data
+ * @param[in] packet The message data
+ * @param[in] len The message data length in bytes
+ * @param[in] rtp_ctx RTP context to get timestamp info from
+ * @param[in] ssrc_peer The remote SSRC in usage for this stream
+ * @param[in] ssrc_local The local SSRC in usage for this stream
+ * @param[in] ssrc_expected The expected SSRC for this RTCP packet
+ * @param[in] video Whether the RTCP packet contains report for video data
+ * @returns The number of fields updated, negative values on errors */
+int janus_rtcp_fix_report_data(char *packet, int len, janus_rtp_switching_context *rtp_ctx, uint32_t ssrc_peer, uint32_t ssrc_local, uint32_t ssrc_expected, gboolean video);
+
 /*! \brief Method to fix an RTCP message (http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00)
  * @param[in] ctx RTCP context to update, if needed (optional)
  * @param[in] packet The message data