MT#57977 support short-packet blocking

Change-Id: I132cfc24262b97a29a7887e717d15e0ac38f439b
(cherry picked from commit 81151b3793)

daemon/call.c

@@ -2516,6 +2516,9 @@ static void __update_init_subscribers(struct call_monologue *ml, GQueue *streams
 
 	recording_setup_monologue(ml);
 
+	if (flags && flags->block_short)
+		ml->block_short = 1;
+
 	for (unsigned int j = 0; j < ml->medias->len; j++) {
 		struct call_media *media = ml->medias->pdata[j];
 		if (!media)

daemon/call_interfaces.c

@@ -1151,6 +1151,11 @@ static void call_ng_flags_flags(struct sdp_ng_flags *out, str *s, void *dummy) {
 		case CSH_LOOKUP("mirror-rtcp"):
 			out->rtcp_mirror = 1;
 			break;
+		case CSH_LOOKUP("block-short"):
+		case CSH_LOOKUP("block-shorts"):
+		case CSH_LOOKUP("block-short-packets"):
+			out->block_short = 1;
+			break;
 		default:
 			// handle values aliases from other dictionaries
 			if (call_ng_flags_prefix(out, s, "from-tags-", call_ng_flags_esc_str_list,

daemon/codec.c

@@ -308,6 +308,7 @@ static void __handler_shutdown(struct codec_handler *handler) {
 	handler->cn_payload_type = -1;
 	handler->pcm_dtmf_detect = 0;
 	handler->passthrough = 0;
+	handler->payload_len = 0;
 
 	codec_handler_free(&handler->dtmf_injector);
 
@@ -1655,6 +1656,15 @@ static int handler_func_passthrough(struct codec_handler *h, struct media_packet
 		ts = ntohl(mp->rtp->timestamp);
 		codec_calc_jitter(mp->ssrc_in, ts, h->source_pt.clock_rate, &mp->tv);
 		codec_calc_lost(mp->ssrc_in, ntohs(mp->rtp->seq_num));
+
+		if (mp->media->monologue->block_short && h->source_pt.codec_def
+				&& h->source_pt.codec_def->fixed_sizes)
+		{
+			if (!h->payload_len)
+				h->payload_len = mp->payload.len;
+			else if (mp->payload.len < h->payload_len)
+				return 0;
+		}
 	}
 
 	mp->media->monologue->dtmf_injection_active = 0;

daemon/media_socket.c

@@ -1561,16 +1561,18 @@ output:
 	redi->local = reti->local;
 	redi->output.tos = call->tos;
 
-	// media silencing
+	// PT manipulations
 	bool silenced = call->silence_media || media->monologue->silence_media
 			|| sink_handler->attrs.silence_media;
-	if (silenced) {
+	bool manipulate_pt = silenced || media->monologue->block_short;
+	if (manipulate_pt && payload_types) {
 		int i = 0;
 		for (GList *l = *payload_types; l; l = l->next) {
 			struct rtp_stats *rs = l->data;
 			struct rtpengine_pt_output *rpt = &redi->output.pt_output[i++];
 			struct codec_handler *ch = codec_handler_get(media, rs->payload_type,
 					sink->media, sink_handler);
+
 			str replace_pattern = STR_NULL;
 			if (silenced && ch->source_pt.codec_def)
 				replace_pattern = ch->source_pt.codec_def->silence_pattern;
@@ -1581,6 +1583,9 @@ output:
 				rpt->replace_pattern_len = replace_pattern.len;
 				memcpy(rpt->replace_pattern, replace_pattern.s, replace_pattern.len);
 			}
+
+			if (media->monologue->block_short && ch->payload_len)
+				rpt->min_payload_len = ch->payload_len;
 		}
 
 	}

docs/ng_control_protocol.md

@@ -807,6 +807,14 @@ Spaces in each string may be replaced by hyphens.
 	Corresponds to the *rtpproxy* `a` flag. Advertises an RTP endpoint which uses asymmetric
 	RTP, which disables learning of endpoint addresses (see below).
 
+* `block short` or `block short packets`
+
+    Enables blocking of short RTP packets for the applicable call participant.
+    Short RTP packets are packets shorter than the expected minimum length,
+    which is determined empirically based on what is observed on the wire.
+    Short packets are simply discarded. This is supported only for codecs for
+    which a fixed packet size is expected (e.g. G.711).
+
 * `debug` or `debugging`
 
 	Enabled full debug logging for this call, regardless of global log level settings.

include/call.h

@@ -539,6 +539,7 @@ struct call_monologue {
 	unsigned int		detect_dtmf:1;
 	unsigned int		no_recording:1;
 	unsigned int		transcoding:1;
+	unsigned int		block_short:1;
 };
 
 struct call_iterator_list {

include/call_interfaces.h

@@ -199,6 +199,7 @@ struct sdp_ng_flags {
 	             drop_traffic_stop:1,
 	             passthrough_on:1,
 	             passthrough_off:1,
+		     block_short:1,
 	             disable_jb:1,
 		     nat_wait:1,
 		     pierce_nat:1;

include/codec.h

@@ -47,6 +47,8 @@ struct codec_handler {
 	unsigned int transcoder:1;
 	unsigned int pcm_dtmf_detect:1;
 
+	size_t payload_len; // for short-packet blocking
+
 	struct ssrc_hash *ssrc_hash;
 	struct codec_handler *input_handler; // == main handler for supp codecs
 	struct codec_handler *output_handler; // == self, or other PT handler

kernel-module/xt_RTPENGINE.c

@@ -1789,11 +1789,12 @@ static int proc_list_show(struct seq_file *f, void *v) {
 		seq_printf(f, "\n");
 
 		for (j = 0; j < g->target.num_payload_types; j++) {
-			if (o->output.pt_output[j].replace_pattern_len)
+			if (o->output.pt_output[j].replace_pattern_len || o->output.pt_output[j].min_payload_len)
 				seq_printf(f, "        RTP payload type %3u: "
-						"%u bytes replacement payload\n",
+						"%u bytes replacement payload, min payload len %u\n",
 						g->target.pt_input[j].pt_num,
-						o->output.pt_output[j].replace_pattern_len);
+						o->output.pt_output[j].replace_pattern_len,
+						o->output.pt_output[j].min_payload_len);
 		}
 
 		proc_list_crypto_print(f, &o->encrypt_rtp, &o->output.encrypt, "encryption");
@@ -5134,7 +5135,7 @@ static void proxy_packet_output_rtcp(struct sk_buff *skb, struct rtpengine_outpu
 	skb_put(skb, rtp->payload_len - pllen);
 }
 
-static void proxy_packet_output_rtXp(struct sk_buff *skb, struct rtpengine_output *o,
+static bool proxy_packet_output_rtXp(struct sk_buff *skb, struct rtpengine_output *o,
 		int rtp_pt_idx,
 		struct rtp_parsed *rtp, int ssrc_idx)
 {
@@ -5144,20 +5145,26 @@ static void proxy_packet_output_rtXp(struct sk_buff *skb, struct rtpengine_outpu
 
 	if (!rtp->ok) {
 		proxy_packet_output_rtcp(skb, o, rtp, ssrc_idx);
-		return;
+		return true;
 	}
 
 	// pattern rewriting
-	if (rtp_pt_idx >= 0 && o->output.pt_output[rtp_pt_idx].replace_pattern_len) {
-		if (o->output.pt_output[rtp_pt_idx].replace_pattern_len == 1)
-			memset(rtp->payload, o->output.pt_output[rtp_pt_idx].replace_pattern[0],
-					rtp->payload_len);
-		else {
-			for (i = 0; i < rtp->payload_len;
-					i += o->output.pt_output[rtp_pt_idx].replace_pattern_len)
-				memcpy(&rtp->payload[i],
-						o->output.pt_output[rtp_pt_idx].replace_pattern,
-						o->output.pt_output[rtp_pt_idx].replace_pattern_len);
+	if (rtp_pt_idx >= 0) {
+		if (o->output.pt_output[rtp_pt_idx].min_payload_len
+				&& rtp->payload_len < o->output.pt_output[rtp_pt_idx].min_payload_len)
+			return false;
+
+		if (o->output.pt_output[rtp_pt_idx].replace_pattern_len) {
+			if (o->output.pt_output[rtp_pt_idx].replace_pattern_len == 1)
+				memset(rtp->payload, o->output.pt_output[rtp_pt_idx].replace_pattern[0],
+						rtp->payload_len);
+			else {
+				for (i = 0; i < rtp->payload_len;
+						i += o->output.pt_output[rtp_pt_idx].replace_pattern_len)
+					memcpy(&rtp->payload[i],
+							o->output.pt_output[rtp_pt_idx].replace_pattern,
+							o->output.pt_output[rtp_pt_idx].replace_pattern_len);
+			}
 		}
 	}
 
@@ -5175,6 +5182,8 @@ static void proxy_packet_output_rtXp(struct sk_buff *skb, struct rtpengine_outpu
 	srtp_encrypt(&o->encrypt_rtp, &o->output.encrypt, rtp, pkt_idx);
 	srtp_authenticate(&o->encrypt_rtp, &o->output.encrypt, rtp, pkt_idx);
 	skb_put(skb, rtp->payload_len - pllen);
+
+	return true;
 }
 
 static int send_proxy_packet_output(struct sk_buff *skb, struct rtpengine_target *g,
@@ -5182,7 +5191,9 @@ static int send_proxy_packet_output(struct sk_buff *skb, struct rtpengine_target
 		struct rtpengine_output *o, struct rtp_parsed *rtp, int ssrc_idx,
 		const struct xt_action_param *par)
 {
-	proxy_packet_output_rtXp(skb, o, rtp_pt_idx, rtp, ssrc_idx);
+	bool send_or_not = proxy_packet_output_rtXp(skb, o, rtp_pt_idx, rtp, ssrc_idx);
+	if (!send_or_not)
+		return 0;
 	return send_proxy_packet(skb, &o->output.src_addr, &o->output.dst_addr, o->output.tos, par);
 }
 

kernel-module/xt_RTPENGINE.h

@@ -100,6 +100,7 @@ struct rtpengine_pt_input {
 	uint32_t clock_rate;
 };
 struct rtpengine_pt_output {
+	unsigned int min_payload_len;
 	char replace_pattern[16];
 	unsigned char replace_pattern_len;
 };

lib/codeclib.c

@@ -256,6 +256,7 @@ static struct codec_def_s __codec_defs[] = {
 			[DTX_SILENCE] = &dtx_method_silence,
 			[DTX_CN] = &dtx_method_cn,
 		},
+		.fixed_sizes = 1,
 	},
 	{
 		.rtpname = "PCMU",
@@ -272,6 +273,7 @@ static struct codec_def_s __codec_defs[] = {
 			[DTX_SILENCE] = &dtx_method_silence,
 			[DTX_CN] = &dtx_method_cn,
 		},
+		.fixed_sizes = 1,
 	},
 	{
 		.rtpname = "G723",
@@ -288,6 +290,7 @@ static struct codec_def_s __codec_defs[] = {
 			[DTX_SILENCE] = &dtx_method_silence,
 			[DTX_CN] = &dtx_method_cn,
 		},
+		.fixed_sizes = 1,
 	},
 	{
 		.rtpname = "G722",
@@ -305,6 +308,7 @@ static struct codec_def_s __codec_defs[] = {
 			[DTX_SILENCE] = &dtx_method_silence,
 			[DTX_CN] = &dtx_method_cn,
 		},
+		.fixed_sizes = 1,
 	},
 	{
 		.rtpname = "QCELP",
@@ -334,6 +338,7 @@ static struct codec_def_s __codec_defs[] = {
 			[DTX_SILENCE] = &dtx_method_silence,
 			[DTX_CN] = &dtx_method_cn,
 		},
+		.fixed_sizes = 1,
 	},
 	{
 		.rtpname = "G729a",
@@ -349,6 +354,7 @@ static struct codec_def_s __codec_defs[] = {
 			[DTX_SILENCE] = &dtx_method_silence,
 			[DTX_CN] = &dtx_method_cn,
 		},
+		.fixed_sizes = 1,
 	},
 #else
 	{
@@ -367,6 +373,7 @@ static struct codec_def_s __codec_defs[] = {
 			[DTX_SILENCE] = &dtx_method_silence,
 			[DTX_CN] = &dtx_method_cn,
 		},
+		.fixed_sizes = 1,
 	},
 	{
 		.rtpname = "G729a",
@@ -383,6 +390,7 @@ static struct codec_def_s __codec_defs[] = {
 			[DTX_SILENCE] = &dtx_method_silence,
 			[DTX_CN] = &dtx_method_cn,
 		},
+		.fixed_sizes = 1,
 	},
 #endif
 	{

lib/codeclib.h

@@ -213,6 +213,7 @@ struct codec_def_s {
 	// flags
 	unsigned int supplemental:1,
 	             dtmf:1, // special case
+		     fixed_sizes:1, // hint for `block-short` feature
 		     amr:1;
 
 	const codec_type_t *codec_type;
@@ -465,6 +466,7 @@ INLINE int decoder_event(decoder_t *dec, enum codec_event event, void *ptr) {
 struct codec_def_s {
 	int dtmf;
 	int supplemental;
+	int fixed_sizes;
 	format_cmp_f * const format_cmp;
 	format_print_f * const format_print;
 	const str silence_pattern;

utils/rtpengine-ng-client

@@ -50,6 +50,7 @@ my @flags = qw(
 	no-passthrough
 	pause
 	early-media
+	block-short
 );
 
 my @string_opts = qw(