honour a=rtcp-fb in SDP even if transport is advertised as RTP/(S)AVP

closes #467

Change-Id: Ib8ea1d6c7b4c9277279399c4319c5efef6834372

daemon/call.c

@@ -1861,7 +1861,8 @@ int monologue_offer_answer(struct call_monologue *other_ml, GQueue *streams,
 			/* copy parameters advertised by the sender of this message */
 			bf_copy_same(&other_media->media_flags, &sp->sp_flags,
 					SHARED_FLAG_RTCP_MUX | SHARED_FLAG_ASYMMETRIC | SHARED_FLAG_UNIDIRECTIONAL |
-					SHARED_FLAG_ICE | SHARED_FLAG_TRICKLE_ICE | SHARED_FLAG_ICE_LITE);
+					SHARED_FLAG_ICE | SHARED_FLAG_TRICKLE_ICE | SHARED_FLAG_ICE_LITE |
+					SHARED_FLAG_RTCP_FB);
 
 			// steal the entire queue of offered crypto params
 			crypto_params_sdes_queue_clear(&other_media->sdes_in);

daemon/media_player.c

@@ -395,7 +395,7 @@ found:
 	}
 	mp->media = media;
 	mp->sink = media->streams.head->data;
-	mp->crypt_handler = determine_handler(&transport_protocols[PROTO_RTP_AVP], media->protocol, 1);
+	mp->crypt_handler = determine_handler(&transport_protocols[PROTO_RTP_AVP], media, 1);
 
 	return 0;
 }

daemon/media_socket.c

@@ -93,6 +93,7 @@ const struct transport_protocol transport_protocols[] = {
 	[PROTO_RTP_AVP] = {
 		.index		= PROTO_RTP_AVP,
 		.name		= "RTP/AVP",
+		.avpf_proto	= PROTO_RTP_AVPF,
 		.rtp		= 1,
 		.srtp		= 0,
 		.avpf		= 0,
@@ -101,6 +102,7 @@ const struct transport_protocol transport_protocols[] = {
 	[PROTO_RTP_SAVP] = {
 		.index		= PROTO_RTP_SAVP,
 		.name		= "RTP/SAVP",
+		.avpf_proto	= PROTO_RTP_SAVPF,
 		.rtp		= 1,
 		.srtp		= 1,
 		.avpf		= 0,
@@ -125,6 +127,7 @@ const struct transport_protocol transport_protocols[] = {
 	[PROTO_UDP_TLS_RTP_SAVP] = {
 		.index		= PROTO_UDP_TLS_RTP_SAVP,
 		.name		= "UDP/TLS/RTP/SAVP",
+		.avpf_proto	= PROTO_UDP_TLS_RTP_SAVPF,
 		.rtp		= 1,
 		.srtp		= 1,
 		.avpf		= 0,
@@ -1177,8 +1180,9 @@ void unkernelize(struct packet_stream *ps) {
 
 
 const struct streamhandler *determine_handler(const struct transport_protocol *in_proto,
-		const struct transport_protocol *out_proto, int must_recrypt)
+		struct call_media *out_media, int must_recrypt)
 {
+	const struct transport_protocol *out_proto = out_media->protocol;
 	const struct streamhandler * const *sh_pp, *sh;
 	const struct streamhandler * const * const *matrix;
 
@@ -1189,7 +1193,15 @@ const struct streamhandler *determine_handler(const struct transport_protocol *i
 	sh_pp = matrix[in_proto->index];
 	if (!sh_pp)
 		goto err;
-	sh = sh_pp[out_proto->index];
+
+	// special handling for RTP/AVP with advertised a=rtcp-fb
+	int out_proto_idx = out_proto->index;
+	if (out_media && MEDIA_ISSET(out_media, RTCP_FB)) {
+		if (!out_proto->avpf && out_proto->avpf_proto)
+			out_proto_idx = out_proto->avpf_proto;
+	}
+	sh = sh_pp[out_proto_idx];
+
 	if (!sh)
 		goto err;
 	return sh;
@@ -1227,7 +1239,7 @@ static void __determine_handler(struct packet_stream *in, const struct packet_st
 				|| crypto_params_cmp(&out->crypto.params, &in->selected_sfd->crypto.params)))
 		must_recrypt = 1;
 
-	in->handler = determine_handler(in_proto, out_proto, must_recrypt);
+	in->handler = determine_handler(in_proto, out->media, must_recrypt);
 	return;
 
 err:

daemon/sdp.c

@@ -203,6 +203,7 @@ struct sdp_attribute {	/* example: a=rtpmap:8 PCMA/8000 */
 		ATTR_IGNORE,
 		ATTR_RTPENGINE,
 		ATTR_PTIME,
+		ATTR_RTCP_FB,
 		ATTR_END_OF_CANDIDATES,
 	} attr;
 
@@ -869,6 +870,9 @@ static int parse_attribute(struct sdp_attribute *a) {
 		case CSH_LOOKUP("end-of-candidates"):
 			a->attr = ATTR_END_OF_CANDIDATES;
 			break;
+		case CSH_LOOKUP("rtcp-fb"):
+			a->attr = ATTR_RTCP_FB;
+			break;
 	}
 
 	return ret;
@@ -1330,6 +1334,10 @@ int sdp_streams(const GQueue *sessions, GQueue *streams, struct sdp_ng_flags *fl
 			if (attr)
 				sp->media_id = attr->value;
 
+			// be ignorant about the contents
+			if (attr_get_by_id(&media->attributes, ATTR_RTCP_FB))
+				SP_SET(sp, RTCP_FB);
+
 			__sdp_ice(sp, media);
 
 			/* determine RTCP endpoint */

include/call.h

@@ -95,6 +95,7 @@ enum call_type {
 #define SHARED_FLAG_TRICKLE_ICE			0x00000400
 #define SHARED_FLAG_ICE_LITE			0x00000800
 #define SHARED_FLAG_UNIDIRECTIONAL		0x00001000
+#define SHARED_FLAG_RTCP_FB			0x00002000
 
 /* struct stream_params */
 #define SP_FLAG_NO_RTCP				0x00010000
@@ -111,6 +112,7 @@ enum call_type {
 #define SP_FLAG_MEDIA_HANDOVER			SHARED_FLAG_MEDIA_HANDOVER
 #define SP_FLAG_TRICKLE_ICE			SHARED_FLAG_TRICKLE_ICE
 #define SP_FLAG_ICE_LITE			SHARED_FLAG_ICE_LITE
+#define SP_FLAG_RTCP_FB				SHARED_FLAG_RTCP_FB
 
 /* struct packet_stream */
 #define PS_FLAG_RTP				0x00010000
@@ -148,6 +150,7 @@ enum call_type {
 #define MEDIA_FLAG_LOOP_CHECK			0x00400000
 #define MEDIA_FLAG_TRANSCODE			0x00800000
 #define MEDIA_FLAG_PTIME_OVERRIDE		0x01000000
+#define MEDIA_FLAG_RTCP_FB			SHARED_FLAG_RTCP_FB
 
 /* access macros */
 #define SP_ISSET(p, f)		bf_isset(&(p)->sp_flags, SP_FLAG_ ## f)

include/media_socket.h

@@ -39,6 +39,7 @@ enum transport_protocol_index {
 struct transport_protocol {
 	enum transport_protocol_index	index;
 	const char			*name;
+	enum transport_protocol_index	avpf_proto;
 	int				rtp:1; /* also set to 1 for SRTP */
 	int				srtp:1;
 	int				avpf:1;
@@ -169,7 +170,7 @@ void __stream_unconfirm(struct packet_stream *);
 
 int media_socket_dequeue(struct media_packet *mp, struct packet_stream *sink);
 const struct streamhandler *determine_handler(const struct transport_protocol *in_proto,
-		const struct transport_protocol *out_proto, int must_recrypt);
+		struct call_media *out_media, int must_recrypt);
 int media_packet_encrypt(rewrite_func encrypt_func, struct packet_stream *out, struct media_packet *mp);
 const struct transport_protocol *transport_protocol(const str *s);