TT#14008 support media echo and blackhole

Change-Id: I9df4680188709867db2b61d97cc5f1e30c59e0d7

README.md

@@ -1433,6 +1433,34 @@ Optionally included keys are:
 	If specified, then this address will be used as destination address for the XMLRPC timeout
 	callback (see `b2b-url` option).
 
+* `media echo` or `media-echo`
+
+	Contains a string to enable a special media echo mode. Recognised values are:
+
+	- `blackhole` or `sinkhole`
+
+		Media arriving from either side of the call is simply discarded
+		and not forwarded.
+
+	- `forward`
+
+		Enables media echo towards the receiver of this message (e.g.
+		the called party if the message is an `offer` from the caller).
+		Media arriving from that side is echoed back to its sender
+		(with a new SSRC if it's RTP). Media arriving from the opposite
+		side is discarded.
+
+	- `backwards`
+
+		Enables media echo towards the sender of this message (i.e. the
+		opposite of `forward`). Media arriving from the other side is
+		discarded.
+
+	- `both`
+
+		Enables media echo towards both the sender and the receiver of
+		this message.
+
 An example of a complete `offer` request dictionary could be (SDP body abbreviated):
 
 	{ "command": "offer", "call-id": "cfBXzDSZqhYNcXM", "from-tag": "mS9rSAn0Cr",

daemon/call.c

@@ -1179,6 +1179,10 @@ static int __init_streams(struct call_media *A, struct call_media *B, const stru
 
 		/* RTP */
 		a->rtp_sink = b;
+		// reflect media - pretent reflection also for blackhole, as otherwise
+		// we get SSRC flip-flops on the opposite side
+		if (MEDIA_ISSET(A, ECHO) || MEDIA_ISSET(A, BLACKHOLE))
+			a->rtp_sink = a;
 		PS_SET(a, RTP); /* XXX technically not correct, could be udptl too */
 
 		__rtp_stats_update(a->rtp_stats, A->codecs_recv);
@@ -1213,6 +1217,8 @@ static int __init_streams(struct call_media *A, struct call_media *B, const stru
 		}
 		else {
 			a->rtcp_sink = b;
+			if (MEDIA_ISSET(A, ECHO) || MEDIA_ISSET(A, BLACKHOLE))
+				a->rtcp_sink = a->rtcp_sibling;
 			PS_SET(a, RTCP);
 			PS_CLEAR(a, IMPLICIT_RTCP);
 		}
@@ -1227,6 +1233,8 @@ static int __init_streams(struct call_media *A, struct call_media *B, const stru
 
 		a->rtp_sink = NULL;
 		a->rtcp_sink = b;
+		if (MEDIA_ISSET(A, ECHO) || MEDIA_ISSET(A, BLACKHOLE))
+			a->rtcp_sink = a;
 		PS_CLEAR(a, RTP);
 		PS_SET(a, RTCP);
 		a->rtcp_sibling = NULL;
@@ -2197,6 +2205,36 @@ int monologue_offer_answer(struct call_monologue *other_ml, GQueue *streams,
 			MEDIA_CLEAR(other_media, RTCP_GEN);
 		}
 
+		if (flags) {
+			switch (flags->media_echo) {
+				case MEO_FWD:
+					MEDIA_SET(media, ECHO);
+					MEDIA_SET(other_media, BLACKHOLE);
+					MEDIA_CLEAR(media, BLACKHOLE);
+					MEDIA_CLEAR(other_media, ECHO);
+					break;
+				case MEO_BKW:
+					MEDIA_SET(media, BLACKHOLE);
+					MEDIA_SET(other_media, ECHO);
+					MEDIA_CLEAR(media, ECHO);
+					MEDIA_CLEAR(other_media, BLACKHOLE);
+					break;
+				case MEO_BOTH:
+					MEDIA_SET(media, ECHO);
+					MEDIA_SET(other_media, ECHO);
+					MEDIA_CLEAR(media, BLACKHOLE);
+					MEDIA_CLEAR(other_media, BLACKHOLE);
+					break;
+				case MEO_BLACKHOLE:
+					MEDIA_SET(media, BLACKHOLE);
+					MEDIA_SET(other_media, BLACKHOLE);
+					MEDIA_CLEAR(media, ECHO);
+					MEDIA_CLEAR(other_media, ECHO);
+				case MEO_DEFAULT:
+					break;
+			}
+		}
+
 		__update_media_protocol(media, other_media, sp, flags);
 		__update_media_id(media, other_media, sp, flags);
 		__endpoint_loop_protect(sp, other_media);

daemon/call_interfaces.c

@@ -1154,6 +1154,31 @@ static void call_ng_process_flags(struct sdp_ng_flags *out, bencode_item_t *inpu
 		else if (!str_cmp(&s, "off"))
 			out->generate_rtcp_off = 1;
 	}
+
+	if (bencode_get_alt(input, "media-echo", "media echo", &s)) {
+		switch (__csh_lookup(&s)) {
+			case CSH_LOOKUP("blackhole"):
+			case CSH_LOOKUP("sinkhole"):
+				out->media_echo = MEO_BLACKHOLE;
+				break;
+			case CSH_LOOKUP("forward"):
+			case CSH_LOOKUP("fwd"):
+			case CSH_LOOKUP("fw"):
+				out->media_echo = MEO_FWD;
+				break;
+			case CSH_LOOKUP("backward"):
+			case CSH_LOOKUP("backwards"):
+			case CSH_LOOKUP("reverse"):
+			case CSH_LOOKUP("back"):
+			case CSH_LOOKUP("bkw"):
+			case CSH_LOOKUP("bk"):
+				out->media_echo = MEO_BKW;
+				break;
+			case CSH_LOOKUP("both"):
+				out->media_echo = MEO_BOTH;
+				break;
+		}
+	}
 }
 static void call_ng_free_flags(struct sdp_ng_flags *flags) {
 	if (flags->codec_strip)

daemon/codec.c

@@ -407,7 +407,10 @@ static GList *__delete_send_codec(struct call_media *sender, GList *link) {
 
 // only called from codec_handlers_update()
 static void __make_passthrough_gsl(struct codec_handler *handler, GSList **handlers) {
-	__make_passthrough(handler);
+	if (MEDIA_ISSET(handler->media, ECHO))
+		__make_passthrough_ssrc(handler);
+	else
+		__make_passthrough(handler);
 	*handlers = g_slist_prepend(*handlers, handler);
 }
 

daemon/media_socket.c

@@ -1141,6 +1141,8 @@ void kernelize(struct packet_stream *stream) {
 		goto no_kernel;
 	if (!stream->endpoint.address.family)
 		goto no_kernel;
+	if (MEDIA_ISSET(media, BLACKHOLE))
+		non_forwarding = 1;
 
         ilog(LOG_INFO, "Kernelizing media stream: %s%s:%d%s",
 			FMT_M(sockaddr_print_buf(&stream->endpoint.address), stream->endpoint.port));
@@ -1183,13 +1185,14 @@ void kernelize(struct packet_stream *stream) {
 	reti.dtls = MEDIA_ISSET(media, DTLS);
 	reti.stun = media->ice_agent ? 1 : 0;
 	reti.non_forwarding = non_forwarding;
+	reti.blackhole = MEDIA_ISSET(media, BLACKHOLE) ? 1 : 0;
 	reti.rtp_stats = MEDIA_ISSET(media, RTCP_GEN) ? 1 : 0;
 
 	__re_address_translate_ep(&reti.dst_addr, &sink->endpoint);
 	__re_address_translate_ep(&reti.src_addr, &sink->selected_sfd->socket.local);
 	if (stream->ssrc_in) {
 		reti.ssrc = htonl(stream->ssrc_in->parent->h.ssrc);
-		if (MEDIA_ISSET(media, TRANSCODE)) {
+		if (MEDIA_ISSET(media, TRANSCODE) || MEDIA_ISSET(media, ECHO)) {
 			reti.ssrc_out = htonl(stream->ssrc_in->ssrc_map_out);
 			reti.transcoding = 1;
 		}
@@ -1473,7 +1476,7 @@ static void __stream_ssrc(struct packet_stream *in_srtp, struct packet_stream *o
 	}
 
 	// make sure we reset the output SSRC if we're not transcoding
-	if (!MEDIA_ISSET(in_srtp->media, TRANSCODE))
+	if (!MEDIA_ISSET(in_srtp->media, TRANSCODE) && !MEDIA_ISSET(in_srtp->media, ECHO))
 		(*ssrc_in_p)->ssrc_map_out = in_ssrc;
 
 	out_ssrc = (*ssrc_in_p)->ssrc_map_out;
@@ -2118,7 +2121,10 @@ static int stream_packet(struct packet_handler_ctx *phc) {
 		goto drop;
 	}
 
-	ret = media_socket_dequeue(&phc->mp, phc->sink);
+	if (!MEDIA_ISSET(phc->mp.media, BLACKHOLE))
+		ret = media_socket_dequeue(&phc->mp, phc->sink);
+	else
+		ret = media_socket_dequeue(&phc->mp, NULL);
 
 	mutex_unlock(&phc->sink->out_lock);
 

include/call.h

@@ -157,6 +157,8 @@ enum call_stream_state {
 #define MEDIA_FLAG_GENERATOR			0x02000000
 #define MEDIA_FLAG_ICE_LITE_SELF		0x04000000
 #define MEDIA_FLAG_RTCP_GEN			0x08000000
+#define MEDIA_FLAG_ECHO				0x10000000
+#define MEDIA_FLAG_BLACKHOLE			0x20000000
 
 /* access macros */
 #define SP_ISSET(p, f)		bf_isset(&(p)->sp_flags, SP_FLAG_ ## f)

include/call_interfaces.h

@@ -64,6 +64,13 @@ struct sdp_ng_flags {
 		ICE_LITE_BKW,
 		ICE_LITE_BOTH,
 	} ice_lite_option:3;
+	enum {
+		MEO_DEFAULT = 0,
+		MEO_BLACKHOLE,
+		MEO_FWD,
+		MEO_BKW,
+		MEO_BOTH,
+	} media_echo:3;
 	unsigned int asymmetric:1,
 	             protocol_accept:1,
 	             no_redis_update:1,

kernel-module/xt_RTPENGINE.c

@@ -1581,8 +1581,10 @@ static int proc_list_show(struct seq_file *f, void *v) {
 	seq_printf(f, "local ");
 	seq_addr_print(f, &g->target.local);
 	seq_printf(f, "\n");
-	proc_list_addr_print(f, "src", &g->target.src_addr);
-	proc_list_addr_print(f, "dst", &g->target.dst_addr);
+	if (!g->target.non_forwarding) {
+		proc_list_addr_print(f, "src", &g->target.src_addr);
+		proc_list_addr_print(f, "dst", &g->target.dst_addr);
+	}
 	proc_list_addr_print(f, "mirror", &g->target.mirror_addr);
 	proc_list_addr_print(f, "expect", &g->target.expected_src);
 	if (g->target.src_mismatch > 0 && g->target.src_mismatch <= ARRAY_SIZE(re_msm_strings))
@@ -1612,6 +1614,8 @@ static int proc_list_show(struct seq_file *f, void *v) {
 		seq_printf(f, "    option: transcoding\n");
 	if (g->target.non_forwarding)
 		seq_printf(f, "    option: non forwarding\n");
+	if (g->target.blackhole)
+		seq_printf(f, "    option: blackhole\n");
 	if (g->target.rtp_stats)
 		seq_printf(f, "    option: RTP stats\n");
 
@@ -4273,8 +4277,11 @@ not_stun:
 	goto skip_error;
 
 src_check_ok:
-	if (g->target.non_forwarding)
+	if (g->target.non_forwarding) {
+		if (g->target.blackhole)
+			error_nf_action = NF_DROP;
 		goto skip1;
+	}
 	if (g->target.dtls && is_dtls(skb))
 		goto skip1;
 

kernel-module/xt_RTPENGINE.h

@@ -120,6 +120,7 @@ struct rtpengine_target_info {
 					do_intercept:1,
 					transcoding:1, // SSRC subst and RTP PT filtering
 					non_forwarding:1, // empty src/dst addr
+					blackhole:1,
 					rtp_stats:1; // requires SSRC and clock_rates to be set
 };
 

utils/rtpengine-ng-client

@@ -89,13 +89,14 @@ GetOptions(
 	'generate-RTCP'			=> \$options{'generate RTCP'},
 	'single-codec'			=> \$options{'single codec'},
 	'reorder-codecs'		=> \$options{'reorder codecs'},
+	'media-echo=s'			=> \$options{'media echo'},
 ) or die;
 
 my $cmd = shift(@ARGV) or die;
 
 my %packet = (command => $cmd);
 
-for my $x (split(/,/, 'from-tag,to-tag,call-id,transport protocol,media address,ICE,address family,DTLS,via-branch,media address,ptime,xmlrpc-callback,metadata,address,file,db-id,code,DTLS-fingerprint,ICE-lite')) {
+for my $x (split(/,/, 'from-tag,to-tag,call-id,transport protocol,media address,ICE,address family,DTLS,via-branch,media address,ptime,xmlrpc-callback,metadata,address,file,db-id,code,DTLS-fingerprint,ICE-lite,media echo')) {
 	defined($options{$x}) and $packet{$x} = \$options{$x};
 }
 for my $x (split(/,/, 'TOS,delete-delay')) {