MT#56465 sdp_create(), set the actual sdp timing

Always ensure to set the actual sdp session timing
if given, when creating SDP using `sdp_create()`.
Otherwise just use default value "0 0".

A new dedicated func `sdp_out_add_timing()` introduced
for that.

Change-Id: Ic02e1a1f55e21b85e50793e1608978ca0951c49d

daemon/call.c

@@ -2657,6 +2657,10 @@ static void __call_monologue_init_from_flags(struct call_monologue *ml, sdp_ng_f
 			ml->sdp_session_name = call_strdup_len(call, flags->session_sdp_name.s,
 						flags->session_sdp_name.len);
 		}
+		/* sdp session timing */
+		if (flags->session_timing.len)
+			ml->sdp_session_timing = call_strdup_len(call, flags->session_timing.s,
+						flags->session_timing.len);
 		/* sdp bandwidth per session level
 		 * 0 value is supported (e.g. b=RR:0 and b=RS:0), to be able to disable rtcp */
 		if (flags->session_rr >= 0)

daemon/sdp.c

@@ -1815,6 +1815,7 @@ int sdp_streams(const sdp_sessions_q *sessions, sdp_streams_q *streams, sdp_ng_f
 		flags->session_sdp_name = session->session_name;
 		flags->session_rr = session->rr;
 		flags->session_rs = session->rs;
+		flags->session_timing = session->session_timing;
 
 		for (__auto_type k = session->media_streams.head; k; k = k->next) {
 			media = k->data;
@@ -3457,6 +3458,18 @@ static void sdp_out_add_session_name(GString *out, struct call_monologue *monolo
 	g_string_append_printf(out, "s=%s\r\n", sdp_session_name);
 }
 
+static void sdp_out_add_timing(GString *out, struct call_monologue *monologue)
+{
+	const char * sdp_session_timing = "0 0"; /* default */
+
+	struct media_subscription *ms = call_get_top_media_subscription(monologue);
+	if (ms && ms->monologue && ms->monologue->sdp_session_timing)
+		sdp_session_timing = ms->monologue->sdp_session_timing;
+
+	/* sdp timing per session level */
+	g_string_append_printf(out, "t=%s\r\n", sdp_session_timing);
+}
+
 static void sdp_out_add_bandwidth(GString *out, struct call_monologue *monologue,
 		struct stream_params *sp, struct call_media *media)
 {
@@ -3552,7 +3565,7 @@ int sdp_create(str *out, struct call_monologue *monologue,
 	sdp_out_add_bandwidth(s, monologue, NULL, NULL);
 
 	/* set timing to always be: 0 0 */
-	g_string_append(s, "t=0 0\r\n");
+	sdp_out_add_timing(s, monologue);
 
 	monologue->sdp_attr_print(s, monologue, flags);
 

include/call.h

@@ -610,6 +610,7 @@ struct call_monologue {
 	GString			*last_out_sdp;
 	char			*sdp_username;
 	char			*sdp_session_name;
+	char			*sdp_session_timing;
 	struct ssrc_hash	*ssrc_hash;
 	str			metadata;
 	struct janus_session	*janus_session;

include/call_interfaces.h

@@ -73,6 +73,7 @@ struct sdp_ng_flags {
 	sdp_attr_q session_attributes;	// top-level (not part of an m= section) SDP session attributes
 	struct sdp_origin session_sdp_orig;
 	str session_sdp_name;
+	str session_timing; /* t= line */
 	int session_rr, session_rs; /* b= bandwidth per session level */
 
 	/* commands to manipulate attr lines in SDP */