MT#56129 Add a flag to force increasing the SDP version

Add a flag to force increasing the SDP version,
even if the SDP hasn't been changed.

And cover it with tests.

Flag name: 'force-increment-sdp-ver'

Additionally fix the name of the 'sdp-version' flag
in the 'rtpengine-ng-client' tool.

Change-Id: I466792668b0cd313b5e21b248dd14cd599333cbd

README.md

@@ -970,6 +970,10 @@ Optionally included keys are:
 		Take control of the version field in the SDP and make sure it's increased every
 		time the SDP changes, and left unchanged if the SDP is the same.
 
+	- `force-increment-sdp-ver`
+
+		Force increasing the SDP version, even if the SDP hasn't been changed.
+
 	- `username`
 
 		Take control of the origin username field in the SDP. With this

daemon/call_interfaces.c

@@ -693,6 +693,10 @@ static void call_ng_flags_replace(struct sdp_ng_flags *out, str *s, void *dummy)
 		case CSH_LOOKUP("session-name"):
 			out->replace_sess_name = 1;
 			break;
+		case CSH_LOOKUP("force-increment-sdp-ver"):
+			out->force_inc_sdp_ver = 1;
+			out->replace_sdp_version = 1;
+			break;
 		case CSH_LOOKUP("sdp-version"):
 		case CSH_LOOKUP("SDP-version"):
 			out->replace_sdp_version = 1;

daemon/sdp.c

@@ -2516,19 +2516,27 @@ static void sdp_version_replace(struct sdp_chopper *chop, GQueue *sessions, stru
 	}
 }
 
-static void sdp_version_check(struct sdp_chopper *chop, GQueue *sessions, struct call_monologue *monologue) {
-	// we really expect only a single session here, but we treat all the same regardless,
-	// and use the same version number on all of them
+static void sdp_version_check(struct sdp_chopper *chop, GQueue *sessions, struct call_monologue *monologue,
+		unsigned int force_increase) {
+	/* We really expect only a single session here, but we treat all the same regardless,
+	 * and use the same version number on all of them */
 
-	// first update all versions to match our single version
+	/* First update all versions to match our single version */
 	sdp_version_replace(chop, sessions, monologue);
-	// then check if we need to change
-	if (!monologue->last_out_sdp)
-		goto dup;
-	if (g_string_equal(monologue->last_out_sdp, chop->output))
-		return;
 
-	// mismatch detected. increment version, update again, and store copy
+	/* Now check if we need to change the version actually.
+	 * The version change will be forced with the 'force_increase',
+	 * and it gets incremented, regardless whether:
+	 * - we have no previously stored SDP,
+	 * - we have previous SDP and it's equal to the current one */
+	if (!force_increase) {
+		if (!monologue->last_out_sdp)
+			goto dup;
+		if (g_string_equal(monologue->last_out_sdp, chop->output))
+			return;
+	}
+
+	/* mismatch detected. increment version, update again, and store copy */
 	monologue->sdp_version++;
 	sdp_version_replace(chop, sessions, monologue);
 	g_string_free(monologue->last_out_sdp, TRUE);
@@ -2835,8 +2843,13 @@ next:
 
 	copy_remainder(chop);
 
+	/* The SDP version gets increased in case:
+	 * - if replace_sdp_version (sdp-version) flag is set and SDP information has been updated, or
+	 * - if the force_inc_sdp_ver (force-increment-sdp-ver) flag is set additionally to replace_sdp_version,
+	 *    which forces version increase regardless changes in the SDP information.
+	 */
 	if (flags->replace_sdp_version)
-		sdp_version_check(chop, sessions, monologue);
+		sdp_version_check(chop, sessions, monologue, flags->force_inc_sdp_ver);
 
 
 	return 0;

include/call_interfaces.h

@@ -113,6 +113,7 @@ struct sdp_ng_flags {
 	             replace_origin:1,
 	             replace_sess_conn:1,
 	             replace_sdp_version:1,
+	             force_inc_sdp_ver:1,
 	             replace_username:1,
 	             replace_sess_name:1,
 	             replace_zero_address:1,

t/auto-daemon-tests.pl

@@ -17192,7 +17192,69 @@ a=sendrecv
 a=rtcp:PORT
 SDP
 
+new_call;
+
+# there is no 'monologue->last_out_sdp', but the version still gets increased
+offer('SDP version force increase', { replace => ['force-increment-sdp-ver'] }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio 2000 RTP/AVP 0
+c=IN IP4 198.51.100.1
+----------------------------
+v=0
+o=- 1545997027 2 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+# there is 'monologue->last_out_sdp' and it's equal to the newly given SDP,
+# but the version still gets increased
+offer('SDP version force increase', { replace => ['force-increment-sdp-ver'] }, <<SDP);
+v=0
+o=- 1545997027 2 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio 2000 RTP/AVP 0
+c=IN IP4 198.51.100.1
+----------------------------
+v=0
+o=- 1545997027 3 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
 
+# there is 'monologue->last_out_sdp' and it's not equal to the newly given SDP,
+# and the version gets increased, as if that would be increased with 'sdp-version'.
+offer('SDP version force increase', { replace => ['force-increment-sdp-ver'] }, <<SDP);
+v=0
+o=- 1545997027 3 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio 2002 RTP/AVP 0
+c=IN IP4 198.51.100.1
+----------------------------
+v=0
+o=- 1545997027 4 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
 
 new_call;
 

utils/rtpengine-ng-client

@@ -29,7 +29,8 @@ GetOptions(
 	'unidirectional'		=> \$options{'unidirectional'},
 	'replace-origin'		=> \$options{'replace-origin'},
 	'replace-session-connection'	=> \$options{'replace-session connection'},
-	'replace-sdp-version'		=> \$options{'replace-sdp version'},
+	'sdp-version'			=> \$options{'replace-sdp version'},
+	'force-increment-sdp-ver'	=> \$options{'force increment sdp version'},
 	'replace-username'		=> \$options{'replace-username'},
 	'replace-session-name'		=> \$options{'replace-session-name'},
 	'replace-zero-address'		=> \$options{'replace-zero-address'},