SDP: Explicitly stop a RTP instance before destoying it.

* Made sdp_add_m_from_rtp_stream() and sdp_add_m_from_udptl_stream()
handle generating disabled/declined streams.

* Added /main/sdp/sdp_merge_asymmetric unit test.  It currently does not
check the offerer side negotiated SDP because that isn't the purpose of
this patch and there is much to be done to handle declined/dummy streams.

* Added T.38 image streams to the /main/sdp/sdp_merge_symmetric and
/main/sdp/sdp_merge_crisscross unit tests.

Change-Id: Ib4dcb3ca4f9a9133b376f4e3302f9a1f963f2b31

1 files changed, 269 insertions, 170 deletions

diff --git a/main/sdp_state.c b/main/sdp_state.c
index 598a6102c..9b116ca54 100644
--- a/main/sdp_state.c
+++ b/main/sdp_state.c
@@ -64,6 +64,11 @@ enum ast_sdp_role {
 
 typedef int (*state_fn)(struct ast_sdp_state *state);
 
+struct sdp_state_rtp {
+	/*! The underlying RTP instance */
+	struct ast_rtp_instance *instance;
+};
+
 struct sdp_state_udptl {
 	/*! The underlying UDPTL instance */
 	struct ast_udptl *instance;
@@ -74,7 +79,7 @@ struct sdp_state_stream {
 	enum ast_media_type type;
 	union {
 		/*! The underlying RTP instance */
-		struct ast_rtp_instance *instance;
+		struct sdp_state_rtp *rtp;
 		/*! The underlying UDPTL instance */
 		struct sdp_state_udptl *udptl;
 	};
@@ -86,6 +91,16 @@ struct sdp_state_stream {
 	struct ast_control_t38_parameters t38_local_params;
 };
 
+static void sdp_state_rtp_destroy(void *obj)
+{
+	struct sdp_state_rtp *rtp = obj;
+
+	if (rtp->instance) {
+		ast_rtp_instance_stop(rtp->instance);
+		ast_rtp_instance_destroy(rtp->instance);
+	}
+}
+
 static void sdp_state_udptl_destroy(void *obj)
 {
 	struct sdp_state_udptl *udptl = obj;
@@ -100,9 +115,7 @@ static void sdp_state_stream_free(struct sdp_state_stream *state_stream)
 	switch (state_stream->type) {
 	case AST_MEDIA_TYPE_AUDIO:
 	case AST_MEDIA_TYPE_VIDEO:
-		if (state_stream->instance) {
-			ast_rtp_instance_destroy(state_stream->instance);
-		}
+		ao2_cleanup(state_stream->rtp);
 		break;
 	case AST_MEDIA_TYPE_IMAGE:
 		ao2_cleanup(state_stream->udptl);
@@ -145,10 +158,10 @@ static void sdp_state_capabilities_free(struct sdp_state_capabilities *capabilit
 static struct ast_sched_context *sched;
 
 /*! \brief Internal function which creates an RTP instance */
-static struct ast_rtp_instance *create_rtp(const struct ast_sdp_options *options,
+static struct sdp_state_rtp *create_rtp(const struct ast_sdp_options *options,
 	enum ast_media_type media_type)
 {
-	struct ast_rtp_instance *rtp;
+	struct sdp_state_rtp *rtp;
 	struct ast_rtp_engine_ice *ice;
 	static struct ast_sockaddr address_rtp;
 	struct ast_sockaddr *media_address = &address_rtp;
@@ -167,38 +180,57 @@ static struct ast_rtp_instance *create_rtp(const struct ast_sdp_options *options
 		}
 	}
 
-	rtp = ast_rtp_instance_new(options->rtp_engine, sched, media_address, NULL);
+	rtp = ao2_alloc_options(sizeof(*rtp), sdp_state_rtp_destroy, AO2_ALLOC_OPT_LOCK_NOLOCK);
 	if (!rtp) {
+		return NULL;
+	}
+
+	rtp->instance = ast_rtp_instance_new(options->rtp_engine, sched, media_address, NULL);
+	if (!rtp->instance) {
 		ast_log(LOG_ERROR, "Unable to create RTP instance using RTP engine '%s'\n",
 			options->rtp_engine);
+		ao2_ref(rtp, -1);
 		return NULL;
 	}
 
-	ast_rtp_instance_set_prop(rtp, AST_RTP_PROPERTY_RTCP, AST_RTP_INSTANCE_RTCP_STANDARD);
-	ast_rtp_instance_set_prop(rtp, AST_RTP_PROPERTY_NAT, options->rtp_symmetric);
+	ast_rtp_instance_set_prop(rtp->instance, AST_RTP_PROPERTY_RTCP,
+		AST_RTP_INSTANCE_RTCP_STANDARD);
+	ast_rtp_instance_set_prop(rtp->instance, AST_RTP_PROPERTY_NAT,
+		options->rtp_symmetric);
 
-	if (options->ice == AST_SDP_ICE_DISABLED && (ice = ast_rtp_instance_get_ice(rtp))) {
-		ice->stop(rtp);
+	if (options->ice == AST_SDP_ICE_DISABLED
+		&& (ice = ast_rtp_instance_get_ice(rtp->instance))) {
+		ice->stop(rtp->instance);
 	}
 
 	if (options->dtmf == AST_SDP_DTMF_RFC_4733 || options->dtmf == AST_SDP_DTMF_AUTO) {
-		ast_rtp_instance_dtmf_mode_set(rtp, AST_RTP_DTMF_MODE_RFC2833);
-		ast_rtp_instance_set_prop(rtp, AST_RTP_PROPERTY_DTMF, 1);
+		ast_rtp_instance_dtmf_mode_set(rtp->instance, AST_RTP_DTMF_MODE_RFC2833);
+		ast_rtp_instance_set_prop(rtp->instance, AST_RTP_PROPERTY_DTMF, 1);
 	} else if (options->dtmf == AST_SDP_DTMF_INBAND) {
-		ast_rtp_instance_dtmf_mode_set(rtp, AST_RTP_DTMF_MODE_INBAND);
+		ast_rtp_instance_dtmf_mode_set(rtp->instance, AST_RTP_DTMF_MODE_INBAND);
 	}
 
-	if (media_type == AST_MEDIA_TYPE_AUDIO &&
-			(options->tos_audio || options->cos_audio)) {
-		ast_rtp_instance_set_qos(rtp, options->tos_audio,
-			options->cos_audio, "SIP RTP Audio");
-	} else if (media_type == AST_MEDIA_TYPE_VIDEO &&
-			(options->tos_video || options->cos_video)) {
-		ast_rtp_instance_set_qos(rtp, options->tos_video,
-			options->cos_video, "SIP RTP Video");
+	switch (media_type) {
+	case AST_MEDIA_TYPE_AUDIO:
+		if (options->tos_audio || options->cos_audio) {
+			ast_rtp_instance_set_qos(rtp->instance, options->tos_audio,
+				options->cos_audio, "SIP RTP Audio");
+		}
+		break;
+	case AST_MEDIA_TYPE_VIDEO:
+		if (options->tos_video || options->cos_video) {
+			ast_rtp_instance_set_qos(rtp->instance, options->tos_video,
+				options->cos_video, "SIP RTP Video");
+		}
+		break;
+	case AST_MEDIA_TYPE_IMAGE:
+	case AST_MEDIA_TYPE_TEXT:
+	case AST_MEDIA_TYPE_UNKNOWN:
+	case AST_MEDIA_TYPE_END:
+		break;
 	}
 
-	ast_rtp_instance_set_last_rx(rtp, time(NULL));
+	ast_rtp_instance_set_last_rx(rtp->instance, time(NULL));
 
 	return rtp;
 }
@@ -278,8 +310,8 @@ static struct sdp_state_capabilities *sdp_initialize_state_capabilities(const st
 		switch (state_stream->type) {
 		case AST_MEDIA_TYPE_AUDIO:
 		case AST_MEDIA_TYPE_VIDEO:
-			state_stream->instance = create_rtp(options, state_stream->type);
-			if (!state_stream->instance) {
+			state_stream->rtp = create_rtp(options, state_stream->type);
+			if (!state_stream->rtp) {
 				sdp_state_stream_free(state_stream);
 				sdp_state_capabilities_free(capabilities);
 				return NULL;
@@ -413,11 +445,11 @@ struct ast_rtp_instance *ast_sdp_state_get_rtp_instance(
 			sdp_state->proposed_capabilities->topology, stream_index)) == AST_MEDIA_TYPE_VIDEO);
 
 	stream_state = sdp_state_get_stream(sdp_state, stream_index);
-	if (!stream_state) {
+	if (!stream_state || !stream_state->rtp) {
 		return NULL;
 	}
 
-	return stream_state->instance;
+	return stream_state->rtp->instance;
 }
 
 struct ast_udptl *ast_sdp_state_get_udptl_instance(
@@ -467,7 +499,7 @@ int ast_sdp_state_get_stream_connection_address(const struct ast_sdp_state *sdp_
 		stream_index))) {
 	case AST_MEDIA_TYPE_AUDIO:
 	case AST_MEDIA_TYPE_VIDEO:
-		ast_rtp_instance_get_local_address(stream_state->instance, address);
+		ast_rtp_instance_get_local_address(stream_state->rtp->instance, address);
 		break;
 	case AST_MEDIA_TYPE_IMAGE:
 		ast_udptl_get_us(stream_state->udptl->instance, address);
@@ -730,7 +762,7 @@ static struct sdp_state_capabilities *merge_capabilities(const struct ast_sdp_st
 			switch (joint_state_stream->type) {
 			case AST_MEDIA_TYPE_AUDIO:
 			case AST_MEDIA_TYPE_VIDEO:
-				joint_state_stream->instance = ao2_bump(local_state_stream->instance);
+				joint_state_stream->rtp = ao2_bump(local_state_stream->rtp);
 				if (is_local) {
 					break;
 				}
@@ -744,8 +776,8 @@ static struct sdp_state_capabilities *merge_capabilities(const struct ast_sdp_st
 					ast_rtp_codecs_payloads_xover(codecs, codecs, NULL);
 				}
 				ast_rtp_codecs_payloads_copy(codecs,
-					ast_rtp_instance_get_codecs(joint_state_stream->instance),
-					joint_state_stream->instance);
+					ast_rtp_instance_get_codecs(joint_state_stream->rtp->instance),
+					joint_state_stream->rtp->instance);
 				break;
 			case AST_MEDIA_TYPE_IMAGE:
 				joint_state_stream->udptl = ao2_bump(local_state_stream->udptl);
@@ -777,9 +809,9 @@ static struct sdp_state_capabilities *merge_capabilities(const struct ast_sdp_st
 			switch (new_stream_type) {
 			case AST_MEDIA_TYPE_AUDIO:
 			case AST_MEDIA_TYPE_VIDEO:
-				joint_state_stream->instance = create_rtp(sdp_state->options,
+				joint_state_stream->rtp = create_rtp(sdp_state->options,
 					new_stream_type);
-				if (!joint_state_stream->instance) {
+				if (!joint_state_stream->rtp) {
 					ast_stream_free(joint_stream);
 					sdp_state_stream_free(joint_state_stream);
 					goto fail;
@@ -954,24 +986,33 @@ static void update_ice(const struct ast_sdp_state *state, struct ast_rtp_instanc
  * sides.
  *
  * \param state The SDP state in which SDPs have been negotiated
- * \param rtp The RTP instance that is being updated
+ * \param rtp The RTP wrapper that is being updated
  * \param options Our locally-supported SDP options
  * \param remote_sdp The SDP we most recently received
  * \param remote_m_line The remote SDP stream that corresponds to the RTP instance we are modifying
  */
-static void update_rtp_after_merge(const struct ast_sdp_state *state, struct ast_rtp_instance *rtp,
+static void update_rtp_after_merge(const struct ast_sdp_state *state,
+	struct sdp_state_rtp *rtp,
     const struct ast_sdp_options *options,
 	const struct ast_sdp *remote_sdp,
 	const struct ast_sdp_m_line *remote_m_line)
 {
-	if (ast_sdp_options_get_rtcp_mux(options) && ast_sdp_m_find_attribute(remote_m_line, "rtcp-mux", -1)) {
-		ast_rtp_instance_set_prop(rtp, AST_RTP_PROPERTY_RTCP, AST_RTP_INSTANCE_RTCP_MUX);
+	if (!rtp) {
+		/* This is a dummy stream */
+		return;
+	}
+
+	if (ast_sdp_options_get_rtcp_mux(options)
+		&& ast_sdp_m_find_attribute(remote_m_line, "rtcp-mux", -1)) {
+		ast_rtp_instance_set_prop(rtp->instance, AST_RTP_PROPERTY_RTCP,
+			AST_RTP_INSTANCE_RTCP_MUX);
 	} else {
-		ast_rtp_instance_set_prop(rtp, AST_RTP_PROPERTY_RTCP, AST_RTP_INSTANCE_RTCP_STANDARD);
+		ast_rtp_instance_set_prop(rtp->instance, AST_RTP_PROPERTY_RTCP,
+			AST_RTP_INSTANCE_RTCP_STANDARD);
 	}
 
 	if (ast_sdp_options_get_ice(options) == AST_SDP_ICE_ENABLED_STANDARD) {
-		update_ice(state, rtp, options, remote_sdp, remote_m_line);
+		update_ice(state, rtp->instance, options, remote_sdp, remote_m_line);
 	}
 }
 
@@ -1000,6 +1041,11 @@ static void update_udptl_after_merge(const struct ast_sdp_state *state, struct s
 	unsigned int fax_max_datagram;
 	struct ast_sockaddr *addrs;
 
+	if (!udptl) {
+		/* This is a dummy stream */
+		return;
+	}
+
 	a_line = ast_sdp_m_find_attribute(remote_m_line, "t38faxmaxdatagram", -1);
 	if (!a_line) {
 		a_line = ast_sdp_m_find_attribute(remote_m_line, "t38maxdatagram", -1);
@@ -1103,7 +1149,7 @@ static int merge_sdps(struct ast_sdp_state *sdp_state, const struct ast_sdp *rem
 		switch (ast_stream_get_type(ast_stream_topology_get_stream(joint_capabilities->topology, i))) {
 		case AST_MEDIA_TYPE_AUDIO:
 		case AST_MEDIA_TYPE_VIDEO:
-			update_rtp_after_merge(sdp_state, state_stream->instance, sdp_state->options,
+			update_rtp_after_merge(sdp_state, state_stream->rtp, sdp_state->options,
 				remote_sdp, ast_sdp_get_m(remote_sdp, i));
 			break;
 		case AST_MEDIA_TYPE_IMAGE:
@@ -1312,123 +1358,163 @@ static int sdp_add_m_from_rtp_stream(struct ast_sdp *sdp, const struct ast_sdp_s
 	struct ast_format_cap *caps;
 	int i;
 	int rtp_code;
+	int rtp_port;
 	int min_packet_size = 0;
 	int max_packet_size = 0;
 	enum ast_media_type media_type;
 	char tmp[64];
-	struct ast_sockaddr address_rtp;
+	struct sdp_state_stream *stream_state;
 	struct ast_rtp_instance *rtp;
 	struct ast_sdp_a_line *a_line;
 
 	stream = ast_stream_topology_get_stream(capabilities->topology, stream_index);
-	rtp = AST_VECTOR_GET(&capabilities->streams, stream_index)->instance;
 
 	ast_assert(sdp && options && stream);
 
+	caps = ast_stream_get_formats(stream);
+
+	stream_state = AST_VECTOR_GET(&capabilities->streams, stream_index);
+	if (stream_state->rtp && caps && ast_format_cap_count(caps)) {
+		rtp = stream_state->rtp->instance;
+	} else {
+		/* This is a disabled stream */
+		rtp = NULL;
+	}
+
 	if (rtp) {
+		struct ast_sockaddr address_rtp;
+
 		if (ast_sdp_state_get_stream_connection_address(sdp_state, 0, &address_rtp)) {
 			return -1;
 		}
+		rtp_port = ast_sockaddr_port(&address_rtp);
 	} else {
-		ast_sockaddr_setnull(&address_rtp);
+		rtp_port = 0;
 	}
 
 	m_line = ast_sdp_m_alloc(
 		ast_codec_media_type2str(ast_stream_get_type(stream)),
-		ast_sockaddr_port(&address_rtp), 1,
+		rtp_port, 1,
 		options->encryption != AST_SDP_ENCRYPTION_DISABLED ? "RTP/SAVP" : "RTP/AVP",
 		NULL);
 	if (!m_line) {
 		return -1;
 	}
 
-	caps = ast_stream_get_formats(stream);
+	if (rtp_port) {
+		/* Stream is not declined/disabled */
+		for (i = 0; i < ast_format_cap_count(caps); i++) {
+			struct ast_format *format = ast_format_cap_get_format(caps, i);
 
-	for (i = 0; i < ast_format_cap_count(caps); i++) {
-		struct ast_format *format = ast_format_cap_get_format(caps, i);
+			rtp_code = ast_rtp_codecs_payload_code(ast_rtp_instance_get_codecs(rtp), 1,
+				format, 0);
+			if (rtp_code == -1) {
+				ast_log(LOG_WARNING,"Unable to get rtp codec payload code for %s\n",
+					ast_format_get_name(format));
+				ao2_ref(format, -1);
+				continue;
+			}
 
-		if ((rtp_code = ast_rtp_codecs_payload_code(ast_rtp_instance_get_codecs(rtp), 1, format, 0)) == -1) {
-			ast_log(LOG_WARNING,"Unable to get rtp codec payload code for %s\n", ast_format_get_name(format));
-			ao2_ref(format, -1);
-			continue;
-		}
+			if (ast_sdp_m_add_format(m_line, options, rtp_code, 1, format, 0)) {
+				ast_sdp_m_free(m_line);
+				ao2_ref(format, -1);
+				return -1;
+			}
+
+			if (ast_format_get_maximum_ms(format)
+				&& ((ast_format_get_maximum_ms(format) < max_packet_size)
+					|| !max_packet_size)) {
+				max_packet_size = ast_format_get_maximum_ms(format);
+			}
 
-		if (ast_sdp_m_add_format(m_line, options, rtp_code, 1, format, 0)) {
-			ast_sdp_m_free(m_line);
 			ao2_ref(format, -1);
-			return -1;
 		}
 
-		if (ast_format_get_maximum_ms(format) &&
-			((ast_format_get_maximum_ms(format) < max_packet_size) || !max_packet_size)) {
-			max_packet_size = ast_format_get_maximum_ms(format);
+		media_type = ast_stream_get_type(stream);
+		if (media_type != AST_MEDIA_TYPE_VIDEO
+			&& (options->dtmf == AST_SDP_DTMF_RFC_4733 || options->dtmf == AST_SDP_DTMF_AUTO)) {
+			i = AST_RTP_DTMF;
+			rtp_code = ast_rtp_codecs_payload_code(
+				ast_rtp_instance_get_codecs(rtp), 0, NULL, i);
+			if (-1 < rtp_code) {
+				if (ast_sdp_m_add_format(m_line, options, rtp_code, 0, NULL, i)) {
+					ast_sdp_m_free(m_line);
+					return -1;
+				}
+
+				snprintf(tmp, sizeof(tmp), "%d 0-16", rtp_code);
+				a_line = ast_sdp_a_alloc("fmtp", tmp);
+				if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+					ast_sdp_a_free(a_line);
+					ast_sdp_m_free(m_line);
+					return -1;
+				}
+			}
 		}
 
-		ao2_ref(format, -1);
-	}
+		/* If ptime is set add it as an attribute */
+		min_packet_size = ast_rtp_codecs_get_framing(ast_rtp_instance_get_codecs(rtp));
+		if (!min_packet_size) {
+			min_packet_size = ast_format_cap_get_framing(caps);
+		}
+		if (min_packet_size) {
+			snprintf(tmp, sizeof(tmp), "%d", min_packet_size);
 
-	media_type = ast_stream_get_type(stream);
-	if (rtp && media_type != AST_MEDIA_TYPE_VIDEO
-		&& (options->dtmf == AST_SDP_DTMF_RFC_4733 || options->dtmf == AST_SDP_DTMF_AUTO)) {
-		i = AST_RTP_DTMF;
-		rtp_code = ast_rtp_codecs_payload_code(
-			ast_rtp_instance_get_codecs(rtp), 0, NULL, i);
-		if (-1 < rtp_code) {
-			if (ast_sdp_m_add_format(m_line, options, rtp_code, 0, NULL, i)) {
+			a_line = ast_sdp_a_alloc("ptime", tmp);
+			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+				ast_sdp_a_free(a_line);
 				ast_sdp_m_free(m_line);
 				return -1;
 			}
+		}
 
-			snprintf(tmp, sizeof(tmp), "%d 0-16", rtp_code);
-			a_line = ast_sdp_a_alloc("fmtp", tmp);
+		if (max_packet_size) {
+			snprintf(tmp, sizeof(tmp), "%d", max_packet_size);
+			a_line = ast_sdp_a_alloc("maxptime", tmp);
 			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
 				ast_sdp_a_free(a_line);
 				ast_sdp_m_free(m_line);
 				return -1;
 			}
 		}
-	}
 
-	if (ast_sdp_m_get_a_count(m_line) == 0) {
-		ast_sdp_m_free(m_line);
-		return 0;
-	}
-
-	/* If ptime is set add it as an attribute */
-	min_packet_size = ast_rtp_codecs_get_framing(ast_rtp_instance_get_codecs(rtp));
-	if (!min_packet_size) {
-		min_packet_size = ast_format_cap_get_framing(caps);
-	}
-	if (min_packet_size) {
-		snprintf(tmp, sizeof(tmp), "%d", min_packet_size);
-
-		a_line = ast_sdp_a_alloc("ptime", tmp);
+		a_line = ast_sdp_a_alloc(ast_sdp_state_get_locally_held(sdp_state, stream_index)
+			? "sendonly" : "sendrecv", "");
 		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
 			ast_sdp_a_free(a_line);
 			ast_sdp_m_free(m_line);
 			return -1;
 		}
-	}
 
-	if (max_packet_size) {
-		snprintf(tmp, sizeof(tmp), "%d", max_packet_size);
-		a_line = ast_sdp_a_alloc("maxptime", tmp);
-		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-			ast_sdp_a_free(a_line);
+		add_ssrc_attributes(m_line, options, rtp);
+	} else {
+		/* Declined/disabled stream */
+		struct ast_sdp_payload *payload;
+		const char *fmt;
+
+		/*
+		 * Add a static payload type placeholder to the declined/disabled stream.
+		 *
+		 * XXX We should use the default payload type in the received offer but
+		 * we don't have that available.
+		 */
+		switch (ast_stream_get_type(stream)) {
+		default:
+		case AST_MEDIA_TYPE_AUDIO:
+			fmt = "0"; /* ulaw */
+			break;
+		case AST_MEDIA_TYPE_VIDEO:
+			fmt = "31"; /* H.261 */
+			break;
+		}
+		payload = ast_sdp_payload_alloc(fmt);
+		if (!payload || ast_sdp_m_add_payload(m_line, payload)) {
+			ast_sdp_payload_free(payload);
 			ast_sdp_m_free(m_line);
 			return -1;
 		}
 	}
 
-	a_line = ast_sdp_a_alloc(ast_sdp_state_get_locally_held(sdp_state, stream_index) ? "sendonly" : "sendrecv", "");
-	if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-		ast_sdp_a_free(a_line);
-		ast_sdp_m_free(m_line);
-		return -1;
-	}
-
-	add_ssrc_attributes(m_line, options, rtp);
-
 	if (ast_sdp_add_m(sdp, m_line)) {
 		ast_sdp_m_free(m_line);
 		return -1;
@@ -1465,27 +1551,37 @@ static int sdp_add_m_from_udptl_stream(struct ast_sdp *sdp, const struct ast_sdp
 	struct ast_sdp_m_line *m_line;
 	struct ast_sdp_payload *payload;
 	char tmp[64];
-	struct ast_sockaddr address_udptl;
 	struct sdp_state_udptl *udptl;
 	struct ast_sdp_a_line *a_line;
 	struct sdp_state_stream *stream_state;
+	int udptl_port;
 
 	stream = ast_stream_topology_get_stream(capabilities->topology, stream_index);
-	udptl = AST_VECTOR_GET(&capabilities->streams, stream_index)->udptl;
 
 	ast_assert(sdp && options && stream);
 
+	stream_state = AST_VECTOR_GET(&capabilities->streams, stream_index);
+	if (stream_state->udptl) {
+		udptl = stream_state->udptl;
+	} else {
+		/* This is a disabled stream */
+		udptl = NULL;
+	}
+
 	if (udptl) {
+		struct ast_sockaddr address_udptl;
+
 		if (ast_sdp_state_get_stream_connection_address(sdp_state, 0, &address_udptl)) {
 			return -1;
 		}
+		udptl_port = ast_sockaddr_port(&address_udptl);
 	} else {
-		ast_sockaddr_setnull(&address_udptl);
+		udptl_port = 0;
 	}
 
 	m_line = ast_sdp_m_alloc(
 		ast_codec_media_type2str(ast_stream_get_type(stream)),
-		ast_sockaddr_port(&address_udptl), 1, "udptl", NULL);
+		udptl_port, 1, "udptl", NULL);
 	if (!m_line) {
 		return -1;
 	}
@@ -1497,97 +1593,100 @@ static int sdp_add_m_from_udptl_stream(struct ast_sdp *sdp, const struct ast_sdp
 		return -1;
 	}
 
-	stream_state = sdp_state_get_stream(sdp_state, stream_index);
-
-	snprintf(tmp, sizeof(tmp), "%u", stream_state->t38_local_params.version);
-	a_line = ast_sdp_a_alloc("T38FaxVersion", tmp);
-	if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-		ast_sdp_a_free(a_line);
-		ast_sdp_m_free(m_line);
-		return -1;
-	}
-
-	snprintf(tmp, sizeof(tmp), "%u", t38_get_rate(stream_state->t38_local_params.rate));
-	a_line = ast_sdp_a_alloc("T38FaxMaxBitRate", tmp);
-	if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-		ast_sdp_a_free(a_line);
-		ast_sdp_m_free(m_line);
-		return -1;
-	}
+	if (udptl_port) {
+		/* Stream is not declined/disabled */
+		stream_state = sdp_state_get_stream(sdp_state, stream_index);
 
-	if (stream_state->t38_local_params.fill_bit_removal) {
-		a_line = ast_sdp_a_alloc("T38FaxFillBitRemoval", "");
+		snprintf(tmp, sizeof(tmp), "%u", stream_state->t38_local_params.version);
+		a_line = ast_sdp_a_alloc("T38FaxVersion", tmp);
 		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
 			ast_sdp_a_free(a_line);
 			ast_sdp_m_free(m_line);
 			return -1;
 		}
-	}
 
-	if (stream_state->t38_local_params.transcoding_mmr) {
-		a_line = ast_sdp_a_alloc("T38FaxTranscodingMMR", "");
+		snprintf(tmp, sizeof(tmp), "%u", t38_get_rate(stream_state->t38_local_params.rate));
+		a_line = ast_sdp_a_alloc("T38FaxMaxBitRate", tmp);
 		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
 			ast_sdp_a_free(a_line);
 			ast_sdp_m_free(m_line);
 			return -1;
 		}
-	}
 
-	if (stream_state->t38_local_params.transcoding_jbig) {
-		a_line = ast_sdp_a_alloc("T38FaxTranscodingJBIG", "");
-		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-			ast_sdp_a_free(a_line);
-			ast_sdp_m_free(m_line);
-			return -1;
+		if (stream_state->t38_local_params.fill_bit_removal) {
+			a_line = ast_sdp_a_alloc("T38FaxFillBitRemoval", "");
+			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+				ast_sdp_a_free(a_line);
+				ast_sdp_m_free(m_line);
+				return -1;
+			}
 		}
-	}
 
-	switch (stream_state->t38_local_params.rate_management) {
-	case AST_T38_RATE_MANAGEMENT_TRANSFERRED_TCF:
-		a_line = ast_sdp_a_alloc("T38FaxRateManagement", "transferredTCF");
-		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-			ast_sdp_a_free(a_line);
-			ast_sdp_m_free(m_line);
-			return -1;
+		if (stream_state->t38_local_params.transcoding_mmr) {
+			a_line = ast_sdp_a_alloc("T38FaxTranscodingMMR", "");
+			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+				ast_sdp_a_free(a_line);
+				ast_sdp_m_free(m_line);
+				return -1;
+			}
 		}
-		break;
-	case AST_T38_RATE_MANAGEMENT_LOCAL_TCF:
-		a_line = ast_sdp_a_alloc("T38FaxRateManagement", "localTCF");
-		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-			ast_sdp_a_free(a_line);
-			ast_sdp_m_free(m_line);
-			return -1;
+
+		if (stream_state->t38_local_params.transcoding_jbig) {
+			a_line = ast_sdp_a_alloc("T38FaxTranscodingJBIG", "");
+			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+				ast_sdp_a_free(a_line);
+				ast_sdp_m_free(m_line);
+				return -1;
+			}
 		}
-		break;
-	}
 
-	snprintf(tmp, sizeof(tmp), "%u", ast_udptl_get_local_max_datagram(udptl->instance));
-	a_line = ast_sdp_a_alloc("T38FaxMaxDatagram", tmp);
-	if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-		ast_sdp_a_free(a_line);
-		ast_sdp_m_free(m_line);
-		return -1;
-	}
+		switch (stream_state->t38_local_params.rate_management) {
+		case AST_T38_RATE_MANAGEMENT_TRANSFERRED_TCF:
+			a_line = ast_sdp_a_alloc("T38FaxRateManagement", "transferredTCF");
+			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+				ast_sdp_a_free(a_line);
+				ast_sdp_m_free(m_line);
+				return -1;
+			}
+			break;
+		case AST_T38_RATE_MANAGEMENT_LOCAL_TCF:
+			a_line = ast_sdp_a_alloc("T38FaxRateManagement", "localTCF");
+			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+				ast_sdp_a_free(a_line);
+				ast_sdp_m_free(m_line);
+				return -1;
+			}
+			break;
+		}
 
-	switch (ast_udptl_get_error_correction_scheme(udptl->instance)) {
-	case UDPTL_ERROR_CORRECTION_NONE:
-		break;
-	case UDPTL_ERROR_CORRECTION_FEC:
-		a_line = ast_sdp_a_alloc("T38FaxUdpEC", "t38UDPFEC");
+		snprintf(tmp, sizeof(tmp), "%u", ast_udptl_get_local_max_datagram(udptl->instance));
+		a_line = ast_sdp_a_alloc("T38FaxMaxDatagram", tmp);
 		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
 			ast_sdp_a_free(a_line);
 			ast_sdp_m_free(m_line);
 			return -1;
 		}
-		break;
-	case UDPTL_ERROR_CORRECTION_REDUNDANCY:
-		a_line = ast_sdp_a_alloc("T38FaxUdpEC", "t38UDPRedundancy");
-		if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
-			ast_sdp_a_free(a_line);
-			ast_sdp_m_free(m_line);
-			return -1;
+
+		switch (ast_udptl_get_error_correction_scheme(udptl->instance)) {
+		case UDPTL_ERROR_CORRECTION_NONE:
+			break;
+		case UDPTL_ERROR_CORRECTION_FEC:
+			a_line = ast_sdp_a_alloc("T38FaxUdpEC", "t38UDPFEC");
+			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+				ast_sdp_a_free(a_line);
+				ast_sdp_m_free(m_line);
+				return -1;
+			}
+			break;
+		case UDPTL_ERROR_CORRECTION_REDUNDANCY:
+			a_line = ast_sdp_a_alloc("T38FaxUdpEC", "t38UDPRedundancy");
+			if (!a_line || ast_sdp_m_add_a(m_line, a_line)) {
+				ast_sdp_a_free(a_line);
+				ast_sdp_m_free(m_line);
+				return -1;
+			}
+			break;
 		}
-		break;
 	}
 
 	if (ast_sdp_add_m(sdp, m_line)) {