Merge "SDP API: Add SSRC-level attributes"

include/asterisk/rtp_engine.h

@@ -599,6 +599,10 @@ struct ast_rtp_engine {
 	void (*available_formats)(struct ast_rtp_instance *instance, struct ast_format_cap *to_endpoint, struct ast_format_cap *to_asterisk, struct ast_format_cap *result);
 	/*! Callback to send CNG */
 	int (*sendcng)(struct ast_rtp_instance *instance, int level);
+	/*! Callback to retrieve local SSRC */
+	unsigned int (*ssrc_get)(struct ast_rtp_instance *instance);
+	/*! Callback to retrieve RTCP SDES CNAME */
+	const char *(*cname_get)(struct ast_rtp_instance *instance);
 	/*! Callback to pointer for optional ICE support */
 	struct ast_rtp_engine_ice *ice;
 	/*! Callback to pointer for optional DTLS SRTP support */
@@ -2389,6 +2393,24 @@ time_t ast_rtp_instance_get_last_rx(const struct ast_rtp_instance *rtp);
  */
 void ast_rtp_instance_set_last_rx(struct ast_rtp_instance *rtp, time_t time);
 
+/*!
+ * \brief Retrieve the local SSRC value that we will be using
+ *
+ * \param rtp The RTP instance
+ * \return The SSRC value
+ */
+unsigned int ast_rtp_instance_get_ssrc(struct ast_rtp_instance *rtp);
+
+/*!
+ * \brief Retrieve the CNAME used in RTCP SDES items
+ *
+ * This is a pointer directly into the RTP struct, not a copy.
+ *
+ * \param rtp The RTP instance
+ * \return the CNAME
+ */
+const char *ast_rtp_instance_get_cname(struct ast_rtp_instance *rtp);
+
 /*! \addtogroup StasisTopicsAndMessages
  * @{
  */

include/asterisk/sdp_options.h

@@ -509,4 +509,23 @@ void ast_sdp_options_set_bind_udptl_to_media_address(struct ast_sdp_options *opt
  */
 unsigned int ast_sdp_options_get_bind_udptl_to_media_address(const struct ast_sdp_options *options);
 
+/*!
+ * \since 15.0.0
+ * \brief Enable setting SSRC level attributes on SDPs
+ *
+ * \param options SDP Options
+ * \param ssrc Boolean indicating if SSRC attributes should be included in generated SDPs
+ */
+void ast_sdp_options_set_ssrc(struct ast_sdp_options *options, unsigned int ssrc);
+
+/*!
+ * \since 15.0.0
+ * \brief Get SDP Options ssrc
+ *
+ * \param options SDP Options
+ *
+ * \returns Whether SSRC-level attributes will be added to our SDP.
+ */
+unsigned int ast_sdp_options_get_ssrc(const struct ast_sdp_options *options);
+
 #endif /* _ASTERISK_SDP_OPTIONS_H */

main/rtp_engine.c

@@ -3340,3 +3340,29 @@ void ast_rtp_instance_set_last_rx(struct ast_rtp_instance *rtp, time_t time)
 {
 	rtp->last_rx = time;
 }
+
+unsigned int ast_rtp_instance_get_ssrc(struct ast_rtp_instance *rtp)
+{
+	unsigned int ssrc = 0;
+
+	ao2_lock(rtp);
+	if (rtp->engine->ssrc_get) {
+		ssrc = rtp->engine->ssrc_get(rtp);
+	}
+	ao2_unlock(rtp);
+
+	return ssrc;
+}
+
+const char *ast_rtp_instance_get_cname(struct ast_rtp_instance *rtp)
+{
+	const char *cname = "";
+
+	ao2_lock(rtp);
+	if (rtp->engine->cname_get) {
+		cname = rtp->engine->cname_get(rtp);
+	}
+	ao2_unlock(rtp);
+
+	return cname;
+}

main/sdp_options.c

@@ -76,6 +76,7 @@ DEFINE_GETTERS_SETTERS_FOR(unsigned int, cos_video);
 DEFINE_GETTERS_SETTERS_FOR(enum ast_sdp_options_ice, ice);
 DEFINE_GETTERS_SETTERS_FOR(enum ast_sdp_options_impl, impl);
 DEFINE_GETTERS_SETTERS_FOR(enum ast_sdp_options_encryption, encryption);
+DEFINE_GETTERS_SETTERS_FOR(unsigned int, ssrc);
 
 static void set_defaults(struct ast_sdp_options *options)
 {

main/sdp_private.h

@@ -43,6 +43,7 @@ struct ast_sdp_options {
 		unsigned int g726_non_standard : 1;
 		unsigned int locally_held : 1;
 		unsigned int rtcp_mux: 1;
+		unsigned int ssrc: 1;
 	};
 	struct {
 		unsigned int tos_audio;

main/sdp_state.c

@@ -1182,6 +1182,37 @@ void ast_sdp_state_set_t38_parameters(struct ast_sdp_state *sdp_state,
 	stream_state->t38_local_params = *params;
 }
 
+/*!
+ * \brief Add SSRC-level attributes if appropriate.
+ *
+ * This function does nothing if the SDP options indicate not to add SSRC-level attributes.
+ *
+ * Currently, the only attribute added is cname, which is retrieved from the RTP instance.
+ *
+ * \param m_line The m_line on which to add the SSRC attributes
+ * \param options Options that indicate what, if any, SSRC attributes to add
+ * \param rtp RTP instance from which we get SSRC-level information
+ */
+static void add_ssrc_attributes(struct ast_sdp_m_line *m_line, const struct ast_sdp_options *options,
+	struct ast_rtp_instance *rtp)
+{
+	struct ast_sdp_a_line *a_line;
+	char attr_buffer[128];
+
+	if (!ast_sdp_options_get_ssrc(options)) {
+		return;
+	}
+
+	snprintf(attr_buffer, sizeof(attr_buffer), "%u cname:%s", ast_rtp_instance_get_ssrc(rtp),
+		ast_rtp_instance_get_cname(rtp));
+
+	a_line = ast_sdp_a_alloc("ssrc", attr_buffer);
+	if (!a_line) {
+		return;
+	}
+	ast_sdp_m_add_a(m_line, a_line);
+}
+
 static int sdp_add_m_from_rtp_stream(struct ast_sdp *sdp, const struct ast_sdp_state *sdp_state,
 	const struct ast_sdp_options *options, const struct sdp_state_capabilities *capabilities, int stream_index)
 {
@@ -1312,6 +1343,8 @@ static int sdp_add_m_from_rtp_stream(struct ast_sdp *sdp, const struct ast_sdp_s
 		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;

res/res_rtp_asterisk.c

@@ -474,6 +474,8 @@ static void ast_rtp_stun_request(struct ast_rtp_instance *instance, struct ast_s
 static void ast_rtp_stop(struct ast_rtp_instance *instance);
 static int ast_rtp_qos_set(struct ast_rtp_instance *instance, int tos, int cos, const char* desc);
 static int ast_rtp_sendcng(struct ast_rtp_instance *instance, int level);
+static unsigned int ast_rtp_get_ssrc(struct ast_rtp_instance *instance);
+static const char *ast_rtp_get_cname(struct ast_rtp_instance *instance);
 
 #ifdef HAVE_OPENSSL_SRTP
 static int ast_rtp_activate(struct ast_rtp_instance *instance);
@@ -1903,6 +1905,8 @@ static struct ast_rtp_engine asterisk_rtp_engine = {
 	.dtls = &ast_rtp_dtls,
 	.activate = ast_rtp_activate,
 #endif
+	.ssrc_get = ast_rtp_get_ssrc,
+	.cname_get = ast_rtp_get_cname,
 };
 
 #ifdef HAVE_OPENSSL_SRTP
@@ -5815,6 +5819,27 @@ static int ast_rtp_sendcng(struct ast_rtp_instance *instance, int level)
 	return res;
 }
 
+/*! \pre instance is locked */
+static unsigned int ast_rtp_get_ssrc(struct ast_rtp_instance *instance)
+{
+	struct ast_rtp *rtp = ast_rtp_instance_get_data(instance);
+
+	return rtp->ssrc;
+}
+
+/*! \pre instance is locked */
+static const char *ast_rtp_get_cname(struct ast_rtp_instance *instance)
+{
+	/* XXX
+	 *
+	 * Asterisk currently puts a zero-length CNAME value in RTCP SDES items,
+	 * meaning our CNAME will always be an empty string. In future, should
+	 * Asterisk actually start using meaningful CNAMEs, this function will
+	 * need to return that instead of an empty string
+	 */
+	return "";
+}
+
 #ifdef HAVE_OPENSSL_SRTP
 static void dtls_perform_setup(struct dtls_details *dtls)
 {

tests/test_sdp.c

@@ -29,6 +29,7 @@
 #include "asterisk/format.h"
 #include "asterisk/format_cache.h"
 #include "asterisk/format_cap.h"
+#include "asterisk/rtp_engine.h"
 
 static int validate_o_line(struct ast_test *test, const struct ast_sdp_o_line *o_line,
 	const char *sdpowner, const char *address_type, const char *address)
@@ -353,26 +354,56 @@ end:
 	return res;
 }
 
+static struct ast_sdp_options *sdp_options_common(void)
+{
+	struct ast_sdp_options *options;
+
+	options = ast_sdp_options_alloc();
+	if (!options) {
+		return NULL;
+	}
+	ast_sdp_options_set_media_address(options, "127.0.0.1");
+	ast_sdp_options_set_sdpowner(options, "me");
+	ast_sdp_options_set_rtp_engine(options, "asterisk");
+	ast_sdp_options_set_impl(options, AST_SDP_IMPL_PJMEDIA);
+
+	return options;
+}
+
 struct sdp_format {
 	enum ast_media_type type;
 	const char *formats;
 };
 
-static struct ast_sdp_state *build_sdp_state(int num_streams, const struct sdp_format *formats)
+/*!
+ * \brief Common method to build an SDP state for a test.
+ *
+ * This uses the passed-in formats to create a stream topology, which is then used to create the SDP
+ * state.
+ *
+ * There is an optional test_options field you can use if your test has specific options you need to
+ * set. If your test does not require anything special, it can just pass NULL for this parameter. If
+ * you do pass in test_options, this function steals ownership of those options.
+ *
+ * \param num_streams The number of elements in the formats array.
+ * \param formats Array of media types and formats that will be in the state.
+ * \param test_options Optional SDP options.
+ */
+static struct ast_sdp_state *build_sdp_state(int num_streams, const struct sdp_format *formats, struct ast_sdp_options *test_options)
 {
 	struct ast_stream_topology *topology = NULL;
 	struct ast_sdp_state *state = NULL;
 	struct ast_sdp_options *options;
 	int i;
 
-	options = ast_sdp_options_alloc();
-	if (!options) {
-		goto end;
+	if (!test_options) {
+		options = sdp_options_common();
+		if (!options) {
+			goto end;
+		}
+	} else {
+		options = test_options;
 	}
-	ast_sdp_options_set_media_address(options, "127.0.0.1");
-	ast_sdp_options_set_sdpowner(options, "me");
-	ast_sdp_options_set_rtp_engine(options, "asterisk");
-	ast_sdp_options_set_impl(options, AST_SDP_IMPL_PJMEDIA);
 
 	topology = ast_stream_topology_alloc();
 	if (!topology) {
@@ -436,7 +467,7 @@ AST_TEST_DEFINE(topology_to_sdp)
 		break;
 	}
 
-	sdp_state = build_sdp_state(ARRAY_LEN(formats), formats);
+	sdp_state = build_sdp_state(ARRAY_LEN(formats), formats, NULL);
 	if (!sdp_state) {
 		goto end;
 	}
@@ -580,7 +611,7 @@ AST_TEST_DEFINE(sdp_to_topology)
 		break;
 	}
 
-	sdp_state = build_sdp_state(ARRAY_LEN(sdp_formats), sdp_formats);
+	sdp_state = build_sdp_state(ARRAY_LEN(sdp_formats), sdp_formats, NULL);
 	if (!sdp_state) {
 		res = AST_TEST_FAIL;
 		goto end;
@@ -704,13 +735,13 @@ AST_TEST_DEFINE(sdp_merge_symmetric)
 		break;
 	}
 
-	sdp_state_offerer = build_sdp_state(ARRAY_LEN(offerer_formats), offerer_formats);
+	sdp_state_offerer = build_sdp_state(ARRAY_LEN(offerer_formats), offerer_formats, NULL);
 	if (!sdp_state_offerer) {
 		res = AST_TEST_FAIL;
 		goto end;
 	}
 
-	sdp_state_answerer = build_sdp_state(ARRAY_LEN(answerer_formats), answerer_formats);
+	sdp_state_answerer = build_sdp_state(ARRAY_LEN(answerer_formats), answerer_formats, NULL);
 	if (!sdp_state_answerer) {
 		res = AST_TEST_FAIL;
 		goto end;
@@ -782,13 +813,13 @@ AST_TEST_DEFINE(sdp_merge_crisscross)
 		break;
 	}
 
-	sdp_state_offerer = build_sdp_state(ARRAY_LEN(offerer_formats), offerer_formats);
+	sdp_state_offerer = build_sdp_state(ARRAY_LEN(offerer_formats), offerer_formats, NULL);
 	if (!sdp_state_offerer) {
 		res = AST_TEST_FAIL;
 		goto end;
 	}
 
-	sdp_state_answerer = build_sdp_state(ARRAY_LEN(answerer_formats), answerer_formats);
+	sdp_state_answerer = build_sdp_state(ARRAY_LEN(answerer_formats), answerer_formats, NULL);
 	if (!sdp_state_answerer) {
 		res = AST_TEST_FAIL;
 		goto end;
@@ -827,6 +858,111 @@ end:
 	return res;
 }
 
+static int validate_ssrc(struct ast_test *test, struct ast_sdp_m_line *m_line,
+	struct ast_rtp_instance *rtp)
+{
+	unsigned int ssrc;
+	const char *cname;
+	struct ast_sdp_a_line *a_line;
+	char attr_value[128];
+
+	ssrc = ast_rtp_instance_get_ssrc(rtp);
+	cname = ast_rtp_instance_get_cname(rtp);
+
+	snprintf(attr_value, sizeof(attr_value), "%u cname:%s", ssrc, cname);
+
+	a_line = ast_sdp_m_find_attribute(m_line, "ssrc", -1);
+	if (!a_line) {
+		ast_test_status_update(test, "Could not find 'ssrc' attribute\n");
+		return -1;
+	}
+
+	if (strcmp(a_line->value, attr_value)) {
+		ast_test_status_update(test, "SDP attribute '%s' did not match expected attribute '%s'\n",
+			a_line->value, attr_value);
+		return -1;
+	}
+
+	return 0;
+}
+
+AST_TEST_DEFINE(sdp_ssrc_attributes)
+{
+	enum ast_test_result_state res;
+	struct ast_sdp_state *test_state = NULL;
+	struct ast_sdp_options *options;
+	struct sdp_format formats[] = {
+		{ AST_MEDIA_TYPE_AUDIO, "ulaw,alaw,g722,opus" },
+	};
+	const struct ast_sdp *sdp;
+	struct ast_sdp_m_line *m_line;
+	struct ast_rtp_instance *rtp;
+
+	switch(cmd) {
+	case TEST_INIT:
+		info->name = "sdp_ssrc_attributes";
+		info->category = "/main/sdp/";
+		info->summary = "Ensure SSRC-level attributes are added to local SDPs";
+		info->description =
+			"An SDP is created and is instructed to include SSRC-level attributes.\n"
+			"This test ensures that the CNAME SSRC-level attribute is present and\n"
+			"that the values match what the RTP instance reports";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	res = AST_TEST_FAIL;
+
+	options = sdp_options_common();
+	if (!options) {
+		ast_test_status_update(test, "Failed to allocate SDP options\n");
+		goto end;
+	}
+	ast_sdp_options_set_ssrc(options, 1);
+
+	test_state = build_sdp_state(ARRAY_LEN(formats), formats, options);
+	if (!test_state) {
+		ast_test_status_update(test, "Failed to create SDP state\n");
+		goto end;
+	}
+
+	sdp = ast_sdp_state_get_local_sdp(test_state);
+	if (!sdp) {
+		ast_test_status_update(test, "Failed to get local SDP\n");
+		goto end;
+	}
+
+	/* Need a couple of sanity checks */
+	if (ast_sdp_get_m_count(sdp) != ARRAY_LEN(formats)) {
+		ast_test_status_update(test, "SDP m count is %d instead of %zu\n",
+			ast_sdp_get_m_count(sdp), ARRAY_LEN(formats));
+		goto end;
+	}
+
+	m_line = ast_sdp_get_m(sdp, 0);
+	if (!m_line) {
+		ast_test_status_update(test, "Failed to get SDP m-line\n");
+		goto end;
+	}
+
+	rtp = ast_sdp_state_get_rtp_instance(test_state, 0);
+	if (!rtp) {
+		ast_test_status_update(test, "Failed to get the RTP instance\n");
+		goto end;
+	}
+
+	if (validate_ssrc(test, m_line, rtp)) {
+		goto end;
+	}
+
+	res = AST_TEST_PASS;
+
+end:
+	ast_sdp_state_free(test_state);
+	return res;
+}
+
 static int unload_module(void)
 {
 	AST_TEST_UNREGISTER(invalid_rtpmap);
@@ -836,6 +972,7 @@ static int unload_module(void)
 	AST_TEST_UNREGISTER(sdp_to_topology);
 	AST_TEST_UNREGISTER(sdp_merge_symmetric);
 	AST_TEST_UNREGISTER(sdp_merge_crisscross);
+	AST_TEST_UNREGISTER(sdp_ssrc_attributes);
 
 	return 0;
 }
@@ -849,6 +986,7 @@ static int load_module(void)
 	AST_TEST_REGISTER(sdp_to_topology);
 	AST_TEST_REGISTER(sdp_merge_symmetric);
 	AST_TEST_REGISTER(sdp_merge_crisscross);
+	AST_TEST_REGISTER(sdp_ssrc_attributes);
 
 	return AST_MODULE_LOAD_SUCCESS;
 }