sdp: remove unused alt_codec field from struct mgcp_rtp_end

The alt_codec field is not used anywhere in the code

- remove unused alt_codec field

Change-Id: I5ff2899e3e61f33eb86f284b50ad8a94a949ed16
Related: OS#3114

include/osmocom/mgcp/mgcp_internal.h

@@ -116,7 +116,6 @@ struct mgcp_rtp_end {
 
 	/* audio codec information */
 	struct mgcp_rtp_codec codec;
-	struct mgcp_rtp_codec alt_codec; /* TODO/XXX: make it generic */
 
 	/* per endpoint data */
 	int  frames_per_packet;

src/libosmo-mgcp/mgcp_conn.c

@@ -132,7 +132,6 @@ static void mgcp_rtp_conn_init(struct mgcp_conn_rtp *conn_rtp, struct mgcp_conn
 	end->output_enabled = 0;
 
 	mgcp_rtp_codec_init(&end->codec);
-	mgcp_rtp_codec_init(&end->alt_codec);
 
 	conn_rtp->rate_ctr_group = rate_ctr_group_alloc(conn, &rate_ctr_group_desc, rate_ctr_index);
 	conn_rtp->state.in_stream.err_ts_ctr = &conn_rtp->rate_ctr_group->ctr[IN_STREAM_ERR_TSTMP_CTR];

src/libosmo-mgcp/mgcp_sdp.c

@@ -205,10 +205,10 @@ static int is_codec_compatible(const struct mgcp_endpoint *endp,
  *  \param[in] endp trunk endpoint.
  *  \param[out] conn associated rtp connection.
  *  \param[out] caller provided memory to store the parsing results.
- *  \returns 1 when codecs are assigned, 0 when no codecs are assigned.
+ *  \returns 1 when a codec is assigned, 0 when no codec is assigned
  *
  *  Note: In conn (conn->end) the function returns the packet duration,
- *  rtp port, rtcp port and the assigned codecs (codec and alt_codec). */
+ *  rtp port, rtcp port and the assigned codec. */
 int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 			struct mgcp_conn_rtp *conn,
 			struct mgcp_parse_data *p)
@@ -218,7 +218,7 @@ int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 	char *line;
 	int maxptime = -1;
 	int i;
-	int codecs_assigned = 0;
+	bool codec_assigned = false;
 	void *tmp_ctx = talloc_new(NULL);
 	struct mgcp_rtp_end *rtp;
 
@@ -277,6 +277,10 @@ int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 				rtp->rtp_port = htons(port);
 				rtp->rtcp_port = htons(port + 1);
 				codecs_used = rc - 1;
+
+				/* So far we have only set the payload type in
+				 * the codec struct. Now we fill up the
+				 * remaining fields of the codec description */
 				codecs_initialize(tmp_ctx, codecs, codecs_used);
 			}
 			break;
@@ -300,11 +304,11 @@ int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 		}
 	}
 
-	/* Now select the primary and alt_codec */
+	/* Now select a suitable codec */
-	for (i = 0; i < codecs_used && codecs_assigned < 2; ++i) {
+	for (i = 0; i < codecs_used; i++) {
-		struct mgcp_rtp_codec *codec = codecs_assigned == 0 ?
-		    &rtp->codec : &rtp->alt_codec;
 
+		/* When no transcoding is available, avoid codecs that would
+		 * require transcoding. */
 		if (endp->tcfg->no_audio_transcoding &&
 		    !is_codec_compatible(endp, &codecs[i])) {
 			LOGP(DLMGCP, LOGL_NOTICE, "Skipping codec %s\n",
@@ -312,12 +316,14 @@ int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 			continue;
 		}
 
-		mgcp_set_audio_info(p->cfg, codec,
+		mgcp_set_audio_info(p->cfg, &rtp->codec,
 				    codecs[i].payload_type, codecs[i].map_line);
-		codecs_assigned += 1;
+
+		codec_assigned = true;
+		break;
 	}
 
-	if (codecs_assigned > 0) {
+	if (codec_assigned) {
 		/* TODO/XXX: Store this per codec and derive it on use */
 		if (maxptime >= 0 && maxptime * rtp->codec.frame_duration_den >
 		    rtp->codec.frame_duration_num * 1500) {
@@ -335,7 +341,10 @@ int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 	}
 
 	talloc_free(tmp_ctx);
-	return codecs_assigned > 0;
+
+	if (codec_assigned)
+		return 1;
+	return 0;
 }
 
 /*! Generate SDP response string.

tests/mgcp/mgcp_test.c

@@ -1244,7 +1244,6 @@ static void test_multilple_codec(void)
 	conn = mgcp_conn_get_rtp(endp, conn_id);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->end.codec.payload_type == 18);
-	OSMO_ASSERT(conn->end.alt_codec.payload_type == 97);
 
 	/* Allocate 2@mgw with three codecs, last one ignored */
 	last_endpoint = -1;
@@ -1260,7 +1259,6 @@ static void test_multilple_codec(void)
 	conn = mgcp_conn_get_rtp(endp, conn_id);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->end.codec.payload_type == 18);
-	OSMO_ASSERT(conn->end.alt_codec.payload_type == 97);
 
 	/* Allocate 3@mgw with no codecs, check for PT == -1 */
 	last_endpoint = -1;
@@ -1276,7 +1274,6 @@ static void test_multilple_codec(void)
 	conn = mgcp_conn_get_rtp(endp, conn_id);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->end.codec.payload_type == -1);
-	OSMO_ASSERT(conn->end.alt_codec.payload_type == -1);
 
 	/* Allocate 4@mgw with a single codec */
 	last_endpoint = -1;
@@ -1292,7 +1289,6 @@ static void test_multilple_codec(void)
 	conn = mgcp_conn_get_rtp(endp, conn_id);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->end.codec.payload_type == 18);
-	OSMO_ASSERT(conn->end.alt_codec.payload_type == -1);
 
 	/* Allocate 5@mgw at select GSM.. */
 	last_endpoint = -1;
@@ -1311,7 +1307,6 @@ static void test_multilple_codec(void)
 	conn = mgcp_conn_get_rtp(endp, conn_id);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->end.codec.payload_type == 3);
-	OSMO_ASSERT(conn->end.alt_codec.payload_type == -1);
 
 	inp = create_msg(MDCX_NAT_DUMMY, conn_id);
 	last_endpoint = -1;
@@ -1323,7 +1318,6 @@ static void test_multilple_codec(void)
 	conn = mgcp_conn_get_rtp(endp, conn_id);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->end.codec.payload_type == 3);
-	OSMO_ASSERT(conn->end.alt_codec.payload_type == -1);
 	OSMO_ASSERT(conn->end.rtp_port == htons(16434));
 	memset(&addr, 0, sizeof(addr));
 	inet_aton("8.8.8.8", &addr);
@@ -1354,7 +1348,6 @@ static void test_multilple_codec(void)
 	conn = mgcp_conn_get_rtp(endp, conn_id);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(conn->end.codec.payload_type == 255);
-	OSMO_ASSERT(conn->end.alt_codec.payload_type == 0);
 
 	talloc_free(cfg);
 }