TT#30403 implement codec stripping

Change-Id: I384aa353b43986656145c443e40a2b96f04c489f

README.md

@@ -1180,6 +1180,19 @@ Optionally included keys are:
 
 	See the `--recording-dir` option above.
 
+* `codec`
+
+	Contains a dictionary controlling various aspects of codecs (or RTP payload types).
+	The following keys are understood:
+
+	* `strip`
+
+		Contains a list of strings. Each string is the name of a codec or RTP payload
+		type that should be removed from the SDP. Codec names are case sensitive, and
+		can be either from the list of codecs explicitly defined by the SDP through
+		an `a=rtpmap` attribute, or can be from the list of RFC-defined codecs. Examples
+		are `PCMU`, `opus`, or `telephone-event`.
+
 
 An example of a complete `offer` request dictionary could be (SDP body abbreviated):
 

daemon/call.c

@@ -1419,17 +1419,30 @@ static void __dtls_logic(const struct sdp_ng_flags *flags,
 		MEDIA_SET(other_media, DTLS);
 }
 
-static void __rtp_payload_types(struct call_media *media, GQueue *types) {
+static void __rtp_payload_types(struct call_media *media, GQueue *types, GHashTable *strip) {
 	struct rtp_payload_type *pt;
 	struct call *call = media->call;
+	static const str __all = STR_CONST_INIT("all");
+
+	// start fresh
+	g_queue_clear(&media->rtp_payload_types_prefs);
 
 	/* we steal the entire list to avoid duplicate allocs */
 	while ((pt = g_queue_pop_head(types))) {
-		/* but we must duplicate the contents */
+		// codec stripping
+		if (strip) {
+			if (g_hash_table_lookup(strip, &pt->encoding)
+					|| g_hash_table_lookup(strip, &__all)) {
+				__payload_type_free(pt);
+				continue;
+			}
+		}
+		/* we must duplicate the contents */
 		call_str_cpy(call, &pt->encoding_with_params, &pt->encoding_with_params);
 		call_str_cpy(call, &pt->encoding, &pt->encoding);
 		call_str_cpy(call, &pt->encoding_parameters, &pt->encoding_parameters);
 		g_hash_table_replace(media->rtp_payload_types, &pt->payload_type, pt);
+		g_queue_push_tail(&media->rtp_payload_types_prefs, pt);
 	}
 }
 
@@ -1553,7 +1566,7 @@ int monologue_offer_answer(struct call_monologue *other_ml, GQueue *streams,
 				MEDIA_SET(other_media, SDES);
 		}
 
-		__rtp_payload_types(media, &sp->rtp_payload_types);
+		__rtp_payload_types(media, &sp->rtp_payload_types, flags->codec_strip);
 
 		/* send and recv are from our POV */
 		bf_copy_same(&media->media_flags, &sp->sp_flags,
@@ -1963,6 +1976,7 @@ static void __call_free(void *p) {
 		g_queue_clear(&md->streams);
 		g_queue_clear(&md->endpoint_maps);
 		g_hash_table_destroy(md->rtp_payload_types);
+		g_queue_clear(&md->rtp_payload_types_prefs);
 		g_slice_free1(sizeof(*md), md);
 	}
 

daemon/call.h

@@ -322,7 +322,9 @@ struct call_media {
 
 	GQueue			streams; /* normally RTP + RTCP */
 	GQueue			endpoint_maps;
+
 	GHashTable		*rtp_payload_types;
+	GQueue			rtp_payload_types_prefs;
 
 	volatile unsigned int	media_flags;
 };

daemon/call_interfaces.c

@@ -528,18 +528,18 @@ INLINE void ng_sdes_option(struct sdp_ng_flags *out, bencode_item_t *it, unsigne
 
 
 static void call_ng_flags_list(struct sdp_ng_flags *out, bencode_item_t *input, const char *key,
-		void (*callback)(struct sdp_ng_flags *out, bencode_item_t *input))
+		void (*callback)(struct sdp_ng_flags *, bencode_item_t *, void *), void *parm)
 {
 	bencode_item_t *list, *it;
 	if ((list = bencode_dictionary_get_expect(input, key, BENCODE_LIST))) {
 		for (it = list->child; it; it = it->sibling)
-			callback(out, it);
+			callback(out, it, parm);
 	}
 }
-static void call_ng_flags_sdes(struct sdp_ng_flags *out, bencode_item_t *it) {
+static void call_ng_flags_sdes(struct sdp_ng_flags *out, bencode_item_t *it, void *dummy) {
 	ng_sdes_option(out, it, 0);
 }
-static void call_ng_flags_rtcp_mux(struct sdp_ng_flags *out, bencode_item_t *it) {
+static void call_ng_flags_rtcp_mux(struct sdp_ng_flags *out, bencode_item_t *it, void *dummy) {
 	if (!bencode_strcmp(it, "offer"))
 		out->rtcp_mux_offer = 1;
 	else if (!bencode_strcmp(it, "require"))
@@ -554,7 +554,7 @@ static void call_ng_flags_rtcp_mux(struct sdp_ng_flags *out, bencode_item_t *it)
 		ilog(LOG_WARN, "Unknown 'rtcp-mux' flag encountered: '"BENCODE_FORMAT"'",
 				BENCODE_FMT(it));
 }
-static void call_ng_flags_replace(struct sdp_ng_flags *out, bencode_item_t *it) {
+static void call_ng_flags_replace(struct sdp_ng_flags *out, bencode_item_t *it, void *dummy) {
 	str_hyphenate(it);
 	if (!bencode_strcmp(it, "origin"))
 		out->replace_origin = 1;
@@ -564,7 +564,29 @@ static void call_ng_flags_replace(struct sdp_ng_flags *out, bencode_item_t *it)
 		ilog(LOG_WARN, "Unknown 'replace' flag encountered: '"BENCODE_FORMAT"'",
 				BENCODE_FMT(it));
 }
-static void call_ng_flags_flags(struct sdp_ng_flags *out, bencode_item_t *it) {
+static void call_ng_flags_codec_list(struct sdp_ng_flags *out, bencode_item_t *it, void *qp) {
+	str *s;
+	s = g_slice_alloc(sizeof(*s));
+	if (!bencode_get_str(it, s)) {
+		g_slice_free1(sizeof(*s), s);
+		return;
+	}
+	g_queue_push_tail((GQueue *) qp, s);
+}
+static void call_ng_flags_codec_ht_strip(bencode_item_t *it, GHashTable *ht, unsigned int strip) {
+	str *s;
+	s = g_slice_alloc(sizeof(*s));
+	if (!bencode_get_str(it, s)) {
+		g_slice_free1(sizeof(*s), s);
+		return;
+	}
+	str_shift(s, strip);
+	g_hash_table_replace(ht, s, s);
+}
+static void call_ng_flags_codec_ht(struct sdp_ng_flags *out, bencode_item_t *it, void *htp) {
+	call_ng_flags_codec_ht_strip(it, htp, 0);
+}
+static void call_ng_flags_flags(struct sdp_ng_flags *out, bencode_item_t *it, void *dummy) {
 	if (it->type !=  BENCODE_STRING)
 		return;
 
@@ -586,8 +608,11 @@ static void call_ng_flags_flags(struct sdp_ng_flags *out, bencode_item_t *it) {
 		out->media_handover = 1;
 	else if (!bencode_strcmp(it, "reset"))
 		out->reset = 1;
+	// XXX unify these
 	else if (it->iov[1].iov_len >= 5 && !memcmp(it->iov[1].iov_base, "SDES-", 5))
 		ng_sdes_option(out, it, 5);
+	else if (it->iov[1].iov_len >= 12 && !memcmp(it->iov[1].iov_base, "codec-strip-", 12))
+		call_ng_flags_codec_ht_strip(it, out->codec_strip, 12);
 	else if (!bencode_strcmp(it, "port-latching"))
 		out->port_latching = 1;
 	else if (!bencode_strcmp(it, "record-call"))
@@ -599,17 +624,18 @@ static void call_ng_flags_flags(struct sdp_ng_flags *out, bencode_item_t *it) {
 				BENCODE_FMT(it));
 }
 static void call_ng_process_flags(struct sdp_ng_flags *out, bencode_item_t *input) {
-	bencode_item_t *list, *it;
+	bencode_item_t *list, *it, *dict;
 	int diridx;
 	str s;
 
 	ZERO(*out);
+	out->codec_strip = g_hash_table_new_full(str_hash, str_equal, str_slice_free, NULL);
 
 	out->trust_address = trust_address_def;
 	out->dtls_passive = dtls_passive_def;
 
-	call_ng_flags_list(out, input, "flags", call_ng_flags_flags);
-	call_ng_flags_list(out, input, "replace", call_ng_flags_replace);
+	call_ng_flags_list(out, input, "flags", call_ng_flags_flags, NULL);
+	call_ng_flags_list(out, input, "replace", call_ng_flags_replace, NULL);
 
 	diridx = 0;
 	if ((list = bencode_dictionary_get_expect(input, "direction", BENCODE_LIST))) {
@@ -649,10 +675,10 @@ static void call_ng_process_flags(struct sdp_ng_flags *out, bencode_item_t *inpu
 					STR_FMT(&s));
 	}
 
-	call_ng_flags_list(out, input, "rtcp-mux", call_ng_flags_rtcp_mux);
+	call_ng_flags_list(out, input, "rtcp-mux", call_ng_flags_rtcp_mux, NULL);
 
 	/* XXX module still needs to support this list */
-	call_ng_flags_list(out, input, "SDES", call_ng_flags_sdes);
+	call_ng_flags_list(out, input, "SDES", call_ng_flags_sdes, NULL);
 
 	bencode_get_alt(input, "transport-protocol", "transport protocol", &out->transport_protocol_str);
 	out->transport_protocol = transport_protocol(&out->transport_protocol_str);
@@ -662,6 +688,15 @@ static void call_ng_process_flags(struct sdp_ng_flags *out, bencode_item_t *inpu
 	out->tos = bencode_dictionary_get_integer(input, "TOS", 256);
 	bencode_get_alt(input, "record-call", "record call", &out->record_call_str);
 	bencode_dictionary_get_str(input, "metadata", &out->metadata);
+
+	if ((dict = bencode_dictionary_get_expect(input, "codec", BENCODE_DICTIONARY))) {
+		call_ng_flags_list(out, dict, "strip", call_ng_flags_codec_ht, out->codec_strip);
+		call_ng_flags_list(out, dict, "offer", call_ng_flags_codec_list, &out->codec_offer);
+	}
+}
+static void call_ng_free_flags(struct sdp_ng_flags *flags) {
+	g_hash_table_destroy(flags->codec_strip);
+	g_queue_clear_full(&flags->codec_offer, str_slice_free);
 }
 
 static const char *call_offer_answer_ng(bencode_item_t *input,
@@ -798,6 +833,7 @@ static const char *call_offer_answer_ng(bencode_item_t *input,
 
 	if (ret == ERROR_NO_FREE_PORTS || ret == ERROR_NO_FREE_LOGS) {
 		ilog(LOG_ERR, "Destroying call");
+		errstr = "Ran out of ports";
 		call_destroy(call);
 	}
 
@@ -811,6 +847,7 @@ static const char *call_offer_answer_ng(bencode_item_t *input,
 out:
 	sdp_free(&parsed);
 	streams_free(&streams);
+	call_ng_free_flags(&flags);
 
 	return errstr;
 }

daemon/call_interfaces.h

@@ -31,6 +31,8 @@ struct sdp_ng_flags {
 	int tos;
 	str record_call_str;
 	str metadata;
+	GHashTable *codec_strip;
+	GQueue codec_offer;
 	int asymmetric:1,
 	    no_redis_update:1,
 	    unidirectional:1,

daemon/sdp.c

@@ -162,6 +162,13 @@ struct attribute_rtpmap {
 	struct rtp_payload_type rtp_pt;
 };
 
+struct attribute_fmtp {
+	str payload_type_str;
+	str format_parms_str;
+
+	unsigned int payload_type;
+};
+
 struct sdp_attribute {
 	str full_line,	/* including a= and \r\n */
 	    line_value,	/* without a= and without \r\n */
@@ -192,6 +199,7 @@ struct sdp_attribute {
 		ATTR_FINGERPRINT,
 		ATTR_SETUP,
 		ATTR_RTPMAP,
+		ATTR_FMTP,
 		ATTR_IGNORE,
 		ATTR_END_OF_CANDIDATES,
 	} attr;
@@ -205,6 +213,7 @@ struct sdp_attribute {
 		struct attribute_fingerprint fingerprint;
 		struct attribute_setup setup;
 		struct attribute_rtpmap rtpmap;
+		struct attribute_fmtp fmtp;
 	} u;
 };
 
@@ -742,6 +751,26 @@ static int parse_attribute_rtpmap(struct sdp_attribute *output) {
 	return 0;
 }
 
+static int parse_attribute_fmtp(struct sdp_attribute *output) {
+	PARSE_DECL;
+	char *ep;
+	struct attribute_fmtp *a;
+
+	output->attr = ATTR_FMTP;
+
+	PARSE_INIT;
+	EXTRACT_TOKEN(u.fmtp.payload_type_str);
+	EXTRACT_TOKEN(u.fmtp.format_parms_str);
+
+	a = &output->u.fmtp;
+
+	a->payload_type = strtoul(a->payload_type_str.s, &ep, 10);
+	if (ep == a->payload_type_str.s)
+		return -1;
+
+	return 0;
+}
+
 static int parse_attribute(struct sdp_attribute *a) {
 	int ret;
 
@@ -777,6 +806,8 @@ static int parse_attribute(struct sdp_attribute *a) {
 				ret = parse_attribute_rtcp(a);
 			else if (!str_cmp(&a->name, "ssrc"))
 				ret = parse_attribute_ssrc(a);
+			else if (!str_cmp(&a->name, "fmtp"))
+				ret = parse_attribute_fmtp(a);
 			break;
 		case 5:
 			if (!str_cmp(&a->name, "group"))
@@ -1408,6 +1439,21 @@ static int replace_transport_protocol(struct sdp_chopper *chop,
 	return 0;
 }
 
+static int replace_codec_list(struct sdp_chopper *chop,
+		struct sdp_media *media, struct call_media *cm)
+{
+	if (cm->rtp_payload_types_prefs.length == 0)
+		return 0; // legacy protocol or usage error
+
+	for (GList *l = cm->rtp_payload_types_prefs.head; l; l = l->next) {
+		struct rtp_payload_type *pt = l->data;
+		chopper_append_printf(chop, " %u", pt->payload_type);
+	}
+	if (skip_over(chop, &media->formats))
+		return -1;
+	return 0;
+}
+
 static int replace_media_port(struct sdp_chopper *chop, struct sdp_media *media, struct packet_stream *ps) {
 	str *port = &media->port;
 	unsigned int p;
@@ -1643,6 +1689,22 @@ static int process_media_attributes(struct sdp_chopper *chop, struct sdp_media *
 				goto strip; // hack/workaround: always remove a=mid
 				break;
 
+			case ATTR_RTPMAP:
+				if (media->rtp_payload_types_prefs.length == 0)
+					break; // legacy protocol or usage error
+				if (!g_hash_table_lookup(media->rtp_payload_types,
+							&attr->u.rtpmap.rtp_pt.payload_type))
+					goto strip;
+				break;
+
+			case ATTR_FMTP:
+				if (media->rtp_payload_types_prefs.length == 0)
+					break; // legacy protocol or usage error
+				if (!g_hash_table_lookup(media->rtp_payload_types,
+							&attr->u.fmtp.payload_type))
+					goto strip;
+				break;
+
 			default:
 				break;
 		}
@@ -1951,6 +2013,8 @@ int sdp_replace(struct sdp_chopper *chop, GQueue *sessions, struct call_monologu
 				        goto error;
 				if (replace_transport_protocol(chop, sdp_media, call_media))
 				        goto error;
+				if (replace_codec_list(chop, sdp_media, call_media))
+					goto error;
 
 				if (sdp_media->connection.parsed) {
 				        if (replace_network_address(chop, &sdp_media->connection.address, ps,

utils/rtpengine-ng-client

@@ -44,6 +44,8 @@ GetOptions(
 	'reset'				=> \$options{'reset'},
 	'port-latching'			=> \$options{'port latching'},
 	'media-address=s'		=> \$options{'media address'},
+	'codec-strip=s@'		=> \$options{'codec-strip'},
+	'flags=s@'			=> \$options{'flags'},
 ) or die;
 
 my $cmd = shift(@ARGV) or die;
@@ -70,6 +72,12 @@ if (defined($options{direction})) {
 	$options{direction} =~ /(.*),(.*)/ or die;
 	$packet{direction} = [$1,$2];
 }
+if ($options{'codec-strip'} && @{$options{'codec-strip'}}) {
+	$packet{codec}{strip} = $options{'codec-strip'};
+}
+if ($options{'flags'} && @{$options{'flags'}}) {
+	push(@{$packet{flags}}, @{$options{'flags'}});
+}
 
 if (defined($options{sdp})) {
 	$packet{sdp} = $options{sdp};