MT#55283 add option `allow no codec media`

Change-Id: I516972d85a26d68b9f9c2a9613294a02448391b6

daemon/call.c

@@ -2456,7 +2456,7 @@ static void codecs_offer(struct call_media *media, struct call_media *other_medi
 	codec_store_offer(&other_media->codecs, &flags->codec_offer, &sp->codecs);
 	if (!other_media->codecs.strip_full)
 		codec_store_offer(&other_media->codecs, &flags->codec_transcode, &sp->codecs);
-	codec_store_check_empty(&other_media->codecs, &sp->codecs);
+	codec_store_check_empty(&other_media->codecs, &sp->codecs, flags);
 	codec_store_accept(&other_media->codecs, &flags->codec_accept, NULL);
 	codec_store_accept(&other_media->codecs, &flags->codec_consume, &sp->codecs);
 	codec_store_track(&other_media->codecs, &flags->codec_mask);
@@ -2489,7 +2489,7 @@ static void codecs_offer(struct call_media *media, struct call_media *other_medi
 	codec_store_strip(&media->codecs, &flags->codec_mask, flags->codec_except);
 	codec_store_offer(&media->codecs, &flags->codec_offer, &sp->codecs);
 	codec_store_transcode(&media->codecs, &flags->codec_transcode, &sp->codecs);
-	codec_store_check_empty(&media->codecs, &sp->codecs);
+	codec_store_check_empty(&media->codecs, &sp->codecs, flags);
 	codec_store_synthesise(&media->codecs, &other_media->codecs);
 
 	// update supp codecs based on actions so far
@@ -2535,7 +2535,7 @@ static void codecs_answer(struct call_media *media, struct call_media *other_med
 				.allow_asymmetric = !!flags->allow_asymmetric_codecs);
 	codec_store_strip(&other_media->codecs, &flags->codec_strip, flags->codec_except);
 	codec_store_offer(&other_media->codecs, &flags->codec_offer, &sp->codecs);
-	codec_store_check_empty(&other_media->codecs, &sp->codecs);
+	codec_store_check_empty(&other_media->codecs, &sp->codecs, flags);
 
 	// update callee side codec handlers again (second pass after the offer) as we
 	// might need to update some handlers, e.g. when supplemental codecs have been

daemon/call_interfaces.c

@@ -976,6 +976,12 @@ void call_ng_flags_flags(str *s, unsigned int idx, helper_arg arg) {
 		case CSH_LOOKUP("allow-asymmetric-codec"):
 			out->allow_asymmetric_codecs = 1;
 			break;
+		case CSH_LOOKUP("allow-no-codec-media"):
+		case CSH_LOOKUP("allow-no-codec-medias"):
+		case CSH_LOOKUP("allow-empty-codec-media"):
+		case CSH_LOOKUP("allow-empty-codec-medias"):
+			out->allow_no_codec_media = 1;
+			break;
 		case CSH_LOOKUP("allow-transcoding"):
 			out->allow_transcoding = 1;
 			break;

daemon/codec.c

@@ -5160,10 +5160,13 @@ void __codec_store_populate_reuse(struct codec_store *dst, struct codec_store *s
 	}
 }
 
-void codec_store_check_empty(struct codec_store *dst, struct codec_store *src) {
+void codec_store_check_empty(struct codec_store *dst, struct codec_store *src, sdp_ng_flags *flags) {
 	if (dst->codec_prefs.length)
 		return;
 
+	if (flags->allow_no_codec_media)
+		return;
+
 	ilog(LOG_WARN, "Usage error: List of codecs empty. Restoring original list of codecs. "
 			"Results may be unexpected.");
 

daemon/sdp.c

@@ -2032,8 +2032,11 @@ static void print_codec_list(GString *s, struct call_media *media) {
 		return;
 	}
 
-	if (media->codecs.codec_prefs.length == 0)
-		return; // legacy protocol or usage error
+	if (media->codecs.codec_prefs.length == 0) {
+		// legacy protocol, usage error, or allow-no-codec-media set. Print something and bail
+		g_string_append(s, "0");
+		return;
+	}
 
 	for (__auto_type l = media->codecs.codec_prefs.head; l; l = l->next) {
 		rtp_payload_type *pt = l->data;
@@ -3052,6 +3055,14 @@ static struct call_media *sdp_out_set_source_media_address(struct call_media *me
 			return source_media;
 	}
 
+	// handle special case: allow-no-codec-media
+	if (flags->allow_no_codec_media && media->codecs.codec_prefs.length == 0
+			&& proto_is_rtp(media->protocol))
+	{
+		// convert to rejected/removed stream
+		*sdp_address = NULL;
+	}
+
 	return NULL;
 }
 

docs/ng_control_protocol.md

@@ -883,6 +883,18 @@ Spaces in each string may be replaced by hyphens.
     Note that payload type number translation will not be performed in this
     situation.
 
+* `allow no codec media`
+
+    Enables special handling for SDP media sections (`m=` lines) that are left
+    without any codecs after codec manipulation operations (in particular codec
+    stripping) have been performed. By default without this option set, a media
+    section without any codecs would be considered a usage error, and the
+    original list of codecs would be restored so that media flow can be
+    established. With this option set, a media section without any codecs would
+    be considered intentionally so, and would be converted to a rejected or
+    removed media section, that is a media section with a zero port, a dummy
+    format list, and further attributes.
+
 * `allow transcoding`
 
 	This flag is only useful in commands that provide an explicit answer SDP to *rtpengine*

include/call_interfaces.h

@@ -190,6 +190,7 @@ struct sdp_ng_flags {
 	             single_codec:1,
 		     reuse_codec:1,
 		     static_codecs:1,
+		     allow_no_codec_media:1,
 		     allow_transcoding:1,
 		     allow_asymmetric_codecs:1,
 		     early_media:1,

include/codec.h

@@ -141,8 +141,8 @@ __attribute__((nonnull(1, 2)))
 void codec_store_strip(struct codec_store *, str_q *strip, str_case_ht except);
 __attribute__((nonnull(1, 2, 3)))
 void codec_store_offer(struct codec_store *, str_q *, struct codec_store *);
-__attribute__((nonnull(1, 2)))
-void codec_store_check_empty(struct codec_store *, struct codec_store *);
+__attribute__((nonnull(1, 2, 3)))
+void codec_store_check_empty(struct codec_store *, struct codec_store *, sdp_ng_flags *);
 __attribute__((nonnull(1, 2)))
 void codec_store_accept(struct codec_store *, str_q *, struct codec_store *);
 __attribute__((nonnull(1, 2)))

t/auto-daemon-tests.pl

@@ -24672,5 +24672,76 @@ $resp = rtpe_req('offer', 'blank line in SDP', { 'from-tag' => ft(), SDP => "v=0
 like($resp->{sdp}, qr/\r\na=foobar\r\na=sendrecv\r\na=rtcp:\d+\r\n$/s, 'SDP matches');
 
 
+new_call;
+
+offer('allow-no-codec-media control', {
+		codec => { strip => ['all'], except => ['PCMA'] },
+	}, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio 2000 RTP/AVP 8
+c=IN IP4 198.51.100.1
+a=rtpmap:8 PCMA/8000
+a=sendrecv
+m=video 3000 RTP/AVP 97
+c=IN IP4 198.51.100.1
+a=rtpmap:97 H264/90000
+a=fmtp:97 profile-level-id=428016;packetization-mode=0;max-mbps=490000;max-fs=8160;max-cpb=200;max-dpb=16320;max-br=5000;max-smbps=490000;max-fps=6000
+a=sendrecv
+----------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 8
+c=IN IP4 203.0.113.1
+a=rtpmap:8 PCMA/8000
+a=sendrecv
+a=rtcp:PORT
+m=video PORT RTP/AVP 97
+c=IN IP4 203.0.113.1
+a=rtpmap:97 H264/90000
+a=fmtp:97 profile-level-id=428016;packetization-mode=0;max-mbps=490000;max-fs=8160;max-cpb=200;max-dpb=16320;max-br=5000;max-smbps=490000;max-fps=6000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+new_call;
+
+offer('allow-no-codec-media control', {
+		codec => { strip => ['all'], except => ['PCMA'] },
+		flags => ['allow no codec media'],
+	}, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio 2000 RTP/AVP 8
+c=IN IP4 198.51.100.1
+a=rtpmap:8 PCMA/8000
+a=sendrecv
+m=video 3000 RTP/AVP 97
+c=IN IP4 198.51.100.1
+a=rtpmap:97 H264/90000
+a=fmtp:97 profile-level-id=428016;packetization-mode=0;max-mbps=490000;max-fs=8160;max-cpb=200;max-dpb=16320;max-br=5000;max-smbps=490000;max-fps=6000
+a=sendrecv
+----------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 8
+c=IN IP4 203.0.113.1
+a=rtpmap:8 PCMA/8000
+a=sendrecv
+a=rtcp:PORT
+m=video 0 RTP/AVP 0
+c=IN IP4 0.0.0.0
+SDP
+
+
+
 #done_testing;NGCP::Rtpengine::AutoTest::terminate('f00');exit;
 done_testing();

utils/rtpengine-ng-client

@@ -54,6 +54,7 @@ my @flags = qw(
 	recording-vsc
 	block-egress
 	directional
+	allow-no-codec-media
 );
 
 my @string_opts = qw(