mgcp-client: MGCP response: pass fmtp to caller

When receiving MGCP responses, so far libosmo-mgcp-client completely
ignored a=fmtp: parameters (like 'octet-align'). Add fmtp parsing to
pass the fmtp string to the caller as-is.

Since the responses so far never included the octet_aligned flags, do
not bother to parse fmtp to populate the legacy items. New callers
should use the fmtp string.

Change-Id: If8ca5c3880cad9e41b80e9d1c821439b0d7b7e23

configure.ac

@@ -189,9 +189,11 @@ AC_OUTPUT(
     libosmo-mgcp-client.pc
     include/Makefile
     include/osmocom/Makefile
+    include/osmocom/sdp/Makefile
     include/osmocom/mgcp_client/Makefile
     include/osmocom/mgcp/Makefile
     src/Makefile
+    src/libosmo-sdp/Makefile
     src/libosmo-mgcp-client/Makefile
     src/libosmo-mgcp/Makefile
     src/osmo-mgw/Makefile
@@ -199,6 +201,7 @@ AC_OUTPUT(
     tests/atlocal
     tests/mgcp_client/Makefile
     tests/mgcp/Makefile
+    tests/sdp/Makefile
     doc/Makefile
     doc/examples/Makefile
     doc/manuals/Makefile

include/Makefile.am

@@ -8,6 +8,8 @@ nobase_include_HEADERS = \
 	osmocom/mgcp_client/mgcp_client_endpoint_fsm.h \
 	osmocom/mgcp_client/mgcp_client_fsm.h \
 	osmocom/mgcp_client/mgcp_client_pool.h \
+	osmocom/sdp/fmtp.h \
+	osmocom/sdp/sdp_strings.h \
 	$(NULL)
 
 noinst_HEADERS = \

include/osmocom/Makefile.am

@@ -1,4 +1,5 @@
 SUBDIRS = \
+	sdp \
 	mgcp_client \
 	mgcp \
 	$(NULL)

include/osmocom/mgcp/mgcp_codec.h

@@ -13,6 +13,7 @@ struct mgcp_conn_rtp;
 void mgcp_codec_summary(struct mgcp_conn_rtp *conn);
 void mgcp_codec_reset_all(struct mgcp_conn_rtp *conn);
 int mgcp_codec_add(struct mgcp_conn_rtp *conn, int payload_type, const char *audio_name, const struct mgcp_codec_param *param);
+int mgcp_codec_add2(struct mgcp_conn_rtp *conn, int payload_type, const char *audio_name, const char *fmtp);
 int mgcp_codec_decide(struct mgcp_conn_rtp *conn_src, struct mgcp_conn_rtp *conn_dst);
 const struct mgcp_rtp_codec *mgcp_codec_pt_find_by_subtype_name(struct mgcp_conn_rtp *conn,
 								const char *subtype_name, unsigned int match_nr);

include/osmocom/mgcp/mgcp_common.h

@@ -59,7 +59,7 @@ enum mgcp_x_osmo_ign {
 	MGCP_X_OSMO_IGN_CALLID = 1,
 };
 
-/* Codec parameters (communicated via SDP/fmtp) */
+/* Deprecated. Use the new fmtp string instead. */
 struct mgcp_codec_param {
 	bool amr_octet_aligned_present;
 	bool amr_octet_aligned;

include/osmocom/mgcp/mgcp_network.h

@@ -83,8 +83,11 @@ struct mgcp_rtp_codec {
 	char audio_name[64];
 	char subtype_name[64];
 
+	/* Deprecated. Use the new fmtp string instead. */
 	bool param_present;
 	struct mgcp_codec_param param;
+
+	char fmtp[256];
 };
 
 /* 'mgcp_rtp_end': basically a wrapper around the RTP+RTCP ports */

include/osmocom/mgcp_client/mgcp_client.h

@@ -77,6 +77,9 @@ struct ptmap {
 
 	/*! payload type number (96-127) */
 	unsigned int pt;
+
+	/*! the MGCP 'a=fmtp:N <...>' string, e.g. "mode-set=1,2,3;octet-align=0". */
+	char fmtp[256];
 };
 
 int ptmap_cmp(const struct ptmap *a, const struct ptmap *b);

include/osmocom/mgcp_client/mgcp_client_fsm.h

@@ -57,10 +57,11 @@ struct mgcp_conn_peer {
 	 * address is set. If != MGCP_CONN_NONE, force this conn mode. */
 	enum mgcp_connection_mode conn_mode;
 
-	/*! If the codec requires additional format parameters (fmtp), those cann be set here, see also
-	 * mgcp_common.h */
-	bool param_present;
-	struct mgcp_codec_param param;
+	/*! Deprectated, use ptmap[].fmtp instead.
+	 * Global codec params. In case the codec requires additional format parameters (fmtp), those can be set
+	 * here, see also mgcp_common.h. The format parameters will be applied on all codecs where applicable. */
+	bool param_present OSMO_DEPRECATED_OUTSIDE_LIBOSMOMGCPCLIENT("use ptmap[].fmtp instead");
+	struct mgcp_codec_param param OSMO_DEPRECATED_OUTSIDE_LIBOSMOMGCPCLIENT("use ptmap[].fmtp instead");
 };
 
 struct osmo_fsm_inst *mgcp_conn_create(struct mgcp_client *mgcp, struct osmo_fsm_inst *parent_fi, uint32_t parent_term_evt,

include/osmocom/sdp/fmtp.h

@@ -0,0 +1,33 @@
+/* Public API for codec management in SDP messages: managing SDP fmtp strings. */
+/*
+ * (C) 2024 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved.
+ *
+ * Author: Neels Janosch Hofmeyr <nhofmeyr@sysmocom.de>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#include <stddef.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+bool osmo_sdp_fmtp_get_val(char *val, size_t val_size, const char *fmtp, const char *option_name);
+int64_t osmo_sdp_fmtp_get_int(const char *fmtp, const char *option_name, int64_t default_value);
+
+bool osmo_sdp_fmtp_amr_is_octet_aligned(const char *fmtp);

include/osmocom/sdp/sdp_strings.h

@@ -0,0 +1,36 @@
+/* Central definition of string tokens used for parsing and composing SDP messages */
+#pragma once
+
+#define OSMO_SDP_STR_MEDIA "m"
+#define OSMO_SDP_STR_ATTRIB "a"
+#define OSMO_SDP_STR_TIME_ACTIVE "t"
+
+#define OSMO_SDP_STR_RTPMAP "rtpmap"
+#define OSMO_SDP_STR_FMTP "fmtp"
+#define OSMO_SDP_STR_PTIME "ptime"
+
+/*! "a=foo:" */
+#define OSMO_SDP_A_PREFIX(STR) OSMO_SDP_STR_ATTRIB "=" STR ":"
+
+/* Media Direction Attributes "a=recvonly", "a=sendrecv", "a=sendonly", "a=inactive" RFC-8866 6.7. */
+#define OSMO_SDP_STR_RECVONLY "recvonly"
+#define OSMO_SDP_STR_SENDRECV "sendrecv"
+#define OSMO_SDP_STR_SENDONLY "sendonly"
+#define OSMO_SDP_STR_INACTIVE "inactive"
+
+/* AMR related tokens */
+
+#define OSMO_SDP_STR_AMR_OCTET_ALIGN "octet-align"
+
+/*! "octet-align=1" */
+#define OSMO_SDP_STR_AMR_OCTET_ALIGN_1  OSMO_SDP_STR_AMR_OCTET_ALIGN "=1"
+
+/*! "octet-align=0".
+ * According to spec [1], "octet-align=0" is identical to omitting 'octet-align' entirely. In Osmocom practice, whether
+ * or not "octet-align=0" is present can make a big difference for osmo-mgw versions 1.12 and older, which do not heed
+ * [1].
+ *
+ * spec [1]: RFC4867, see details in description of osmo_sdp_fmtp_amr_is_octet_aligned().
+ */
+#define OSMO_SDP_STR_AMR_OCTET_ALIGN_0  OSMO_SDP_STR_AMR_OCTET_ALIGN "=0"
+

src/Makefile.am

@@ -15,6 +15,7 @@ AM_CFLAGS = \
 
 # Libraries
 SUBDIRS = \
+	libosmo-sdp \
 	libosmo-mgcp-client \
 	libosmo-mgcp \
 	$(NULL)

src/libosmo-mgcp-client/Makefile.am

@@ -40,6 +40,7 @@ libosmo_mgcp_client_la_LDFLAGS = \
 	$(NULL)
 
 libosmo_mgcp_client_la_LIBADD = \
+	$(top_builddir)/src/libosmo-sdp/libosmo-sdp.la \
 	$(LIBOSMOCORE_LIBS) \
 	$(LIBOSMOVTY_LIBS) \
 	$(NULL)

src/libosmo-mgcp-client/mgcp_client.c

@@ -29,6 +29,7 @@
 
 #include <osmocom/mgcp_client/mgcp_client.h>
 #include <osmocom/mgcp_client/mgcp_client_internal.h>
+#include <osmocom/sdp/sdp_strings.h>
 
 #include <osmocom/abis/e1_input.h>
 
@@ -388,11 +389,12 @@ static int mgcp_parse_audio_ptime_rtpmap(struct mgcp_response *r, const char *li
 {
 	unsigned int pt;
 	unsigned int i;
-	char codec_resp[64];
+	char codec_resp[256];
 	int rc;
 
-#define A_PTIME "a=ptime:"
-#define A_RTPMAP "a=rtpmap:"
+#define A_PTIME OSMO_SDP_A_PREFIX(OSMO_SDP_STR_PTIME)
+#define A_RTPMAP OSMO_SDP_A_PREFIX(OSMO_SDP_STR_RTPMAP)
+#define A_FMTP OSMO_SDP_A_PREFIX(OSMO_SDP_STR_FMTP)
 
 	if (osmo_str_startswith(line, A_PTIME)) {
 		if (sscanf(line, A_PTIME "%u", &r->ptime) != 1) {
@@ -401,7 +403,7 @@ static int mgcp_parse_audio_ptime_rtpmap(struct mgcp_response *r, const char *li
 			return -EINVAL;
 		}
 	} else if (osmo_str_startswith(line, A_RTPMAP)) {
-		if (sscanf(line, A_RTPMAP "%d %63s", &pt, codec_resp) != 2) {
+		if (sscanf(line, A_RTPMAP "%d %255s", &pt, codec_resp) != 2) {
 			LOGP(DLMGCP, LOGL_ERROR,
 			     "Failed to parse SDP parameter, invalid rtpmap: %s\n", osmo_quote_str(line, -1));
 			return -EINVAL;
@@ -440,6 +442,42 @@ static int mgcp_parse_audio_ptime_rtpmap(struct mgcp_response *r, const char *li
 			.codec = rc,
 		};
 		r->ptmap_len++;
+
+	} else if (osmo_str_startswith(line, A_FMTP)) {
+		if (sscanf(line, A_FMTP "%d %255s", &pt, codec_resp) != 2) {
+			LOGP(DLMGCP, LOGL_ERROR,
+			     "Failed to parse SDP parameter, invalid fmtp: %s\n", osmo_quote_str(line, -1));
+			return -EINVAL;
+		}
+
+		/* Earlier, a line like "m=audio 16002 RTP/AVP 98 112 3" established the desired order of payloads, now
+		 * enrich it with actual codec information provided by "a=rtpmap:..." entries.
+		 * For each, find the entry with the right pt number and add the info there. */
+
+		for (i = 0; i < r->ptmap_len; i++) {
+			if (r->ptmap[i].pt != pt)
+				continue;
+			OSMO_STRLCPY_ARRAY(r->ptmap[r->ptmap_len].fmtp, codec_resp);
+			return 0;
+		}
+
+		/* No entry was found. This is an error in the MGCP protocol, but let's just add another entry
+		 * anyway, to not make it look like it was never there. */
+		LOGP(DLMGCP, LOGL_ERROR,
+		     "error in MGCP message: 'a=fmtp:%u' has no matching entry in 'm=audio ... %u'\n",
+		     pt, pt);
+		if (r->ptmap_len >= ARRAY_SIZE(r->ptmap)) {
+			LOGP(DLMGCP, LOGL_ERROR,
+			     "cannot parse all codecs: can only store up to %zu rtpmap entries.\n",
+			     ARRAY_SIZE(r->ptmap));
+			return -ENOSPC;
+		}
+		r->ptmap[r->ptmap_len] = (struct ptmap){
+			.pt = pt,
+			.codec = -1,
+		};
+		OSMO_STRLCPY_ARRAY(r->ptmap[r->ptmap_len].fmtp, codec_resp);
+		r->ptmap_len++;
 	}
 
 	return 0;
@@ -1377,13 +1415,20 @@ static int add_sdp(struct msgb *msg, struct mgcp_msg *mgcp_msg, struct mgcp_clie
 	}
 
 	/* Add optional codec parameters (fmtp) */
-	if (mgcp_msg->param_present) {
-		for (i = 0; i < mgcp_msg->ptmap_len; i++) {
-			/* The following is only applicable for AMR */
-			if (mgcp_msg->ptmap[i].codec != CODEC_AMR_8000_1
-			    && mgcp_msg->ptmap[i].codec != CODEC_AMRWB_16000_1)
-				continue;
+	for (i = 0; i < mgcp_msg->ptmap_len; i++) {
+		/* Add fmtp string, if any is set. */
+		if (mgcp_msg->ptmap[i].fmtp[0]) {
+			MSGB_PRINTF_OR_RET("a=fmtp:%u %s\r\n", mgcp_msg->ptmap[i].pt, mgcp_msg->ptmap[i].fmtp);
+			continue;
+		}
+
+		/* LEGACY COMPAT. Fill in fmtp with the legacy mgcp_msg->param, if any, when no individual fmtp is set
+		 * on the codec. We only ever supported AMR fmtp in mgcp_msg->param. */
+		if (mgcp_msg->param_present
+		    && (mgcp_msg->ptmap[i].codec == CODEC_AMR_8000_1
+			|| mgcp_msg->ptmap[i].codec == CODEC_AMRWB_16000_1)) {
 			pt = mgcp_msg->ptmap[i].pt;
+
 			if (mgcp_msg->param.amr_octet_aligned_present && mgcp_msg->param.amr_octet_aligned)
 				MSGB_PRINTF_OR_RET("a=fmtp:%u octet-align=1\r\n", pt);
 			else if (mgcp_msg->param.amr_octet_aligned_present && !mgcp_msg->param.amr_octet_aligned)
@@ -1621,5 +1666,8 @@ int ptmap_cmp(const struct ptmap *a, const struct ptmap *b)
 	rc = OSMO_CMP(a->codec, b->codec);
 	if (rc)
 		return rc;
-	return OSMO_CMP(a->pt, b->pt);
+	rc = OSMO_CMP(a->pt, b->pt);
+	if (rc)
+		return rc;
+	return strcmp(a->fmtp, b->fmtp);
 }

src/libosmo-mgcp/Makefile.am

@@ -19,15 +19,15 @@ AM_LDFLAGS = \
 	$(COVERAGE_LDFLAGS) \
 	$(NULL)
 
-noinst_LIBRARIES = \
-	libosmo-mgcp.a \
+noinst_LTLIBRARIES = \
+	libosmo-mgcp.la \
 	$(NULL)
 
 noinst_HEADERS = \
 	g711common.h \
 	$(NULL)
 
-libosmo_mgcp_a_SOURCES = \
+libosmo_mgcp_la_SOURCES = \
 	mgcp_protocol.c \
 	mgcp_network.c \
 	mgcp_vty.c \
@@ -43,3 +43,13 @@ libosmo_mgcp_a_SOURCES = \
 	mgcp_e1.c \
 	mgcp_iuup.c \
 	$(NULL)
+
+libosmo_mgcp_la_LIBADD = \
+	$(top_builddir)/src/libosmo-sdp/libosmo-sdp.la \
+	$(LIBOSMOCORE_LIBS) \
+	$(LIBOSMOGSM_LIBS) \
+	$(LIBOSMOVTY_LIBS) \
+	$(LIBOSMONETIF_LIBS) \
+	$(LIBOSMOABIS_LIBS) \
+	$(LIBOSMOTRAU_LIBS) \
+	$(NULL)

src/libosmo-mgcp/mgcp_codec.c

@@ -24,6 +24,10 @@
 #include <osmocom/mgcp/mgcp_endp.h>
 #include <osmocom/mgcp/mgcp_trunk.h>
 #include <osmocom/mgcp/mgcp_codec.h>
+
+#include <osmocom/sdp/sdp_strings.h>
+#include <osmocom/sdp/fmtp.h>
+
 #include <errno.h>
 
 /* Helper function to dump codec information of a specified codec to a printable
@@ -116,9 +120,9 @@ void mgcp_codec_reset_all(struct mgcp_conn_rtp *conn)
  *  \param[out] conn related rtp-connection.
  *  \param[in] payload_type codec type id (e.g. 3 for GSM, -1 when undefined).
  *  \param[in] audio_name audio codec name, in uppercase (e.g. "GSM/8000/1").
- *  \param[in] param optional codec parameters (set to NULL when unused).
+ *  \param[in] fmtp optional codec parameters (set to NULL when unused).
  *  \returns 0 on success, -EINVAL on failure. */
-int mgcp_codec_add(struct mgcp_conn_rtp *conn, int payload_type, const char *audio_name, const struct mgcp_codec_param *param)
+int mgcp_codec_add2(struct mgcp_conn_rtp *conn, int payload_type, const char *audio_name, const char *fmtp)
 {
 	int rate;
 	int channels;
@@ -261,12 +265,16 @@ int mgcp_codec_add(struct mgcp_conn_rtp *conn, int payload_type, const char *aud
 		}
 	}
 
-	/* Copy over optional codec parameters */
-	if (param) {
-		codec->param = *param;
-		codec->param_present = true;
-	} else
-		codec->param_present = false;
+	if (fmtp) {
+		OSMO_STRLCPY_ARRAY(codec->fmtp, fmtp);
+		if (strlen(codec->fmtp) != strlen(fmtp)) {
+			LOGP(DLMGCP, LOGL_ERROR, "fmtp too long: %zu > %zu\n", strlen(fmtp), strlen(codec->fmtp));
+			/* let's just hope what is there is still useful, worst case the call's audio doesn't work */
+		}
+	}
+
+	/* legacy */
+	codec->param_present = false;
 
 	conn->end.codecs_assigned++;
 	return 0;
@@ -276,23 +284,33 @@ error:
 	return -EINVAL;
 }
 
-/* Return true if octet-aligned is set in the given codec. Default to octet-aligned=0, i.e. bandwidth-efficient mode.
- * See RFC4867 "RTP Payload Format for AMR and AMR-WB" sections "8.1. AMR Media Type Registration" and "8.2. AMR-WB
- * Media Type Registration":
- *
- *    octet-align: Permissible values are 0 and 1.  If 1, octet-aligned
- *                 operation SHALL be used.  If 0 or if not present,
- *                 bandwidth-efficient operation is employed.
- *
- * https://tools.ietf.org/html/rfc4867
- */
+/*! Legacy compat, use mgcp_codec_add2() instead to be able to pass any fmtp besides AMR octet-align=1.
+ * Add codec configuration depending on payload type and/or codec name. This
+ *  function uses the input parameters to extrapolate the full codec information.
+ *  \param[out] codec configuration (caller provided memory).
+ *  \param[out] conn related rtp-connection.
+ *  \param[in] payload_type codec type id (e.g. 3 for GSM, -1 when undefined).
+ *  \param[in] audio_name audio codec name, in uppercase (e.g. "GSM/8000/1").
+ *  \param[in] param optional codec parameters (set to NULL when unused).
+ *  \returns 0 on success, -EINVAL on failure. */
+int mgcp_codec_add(struct mgcp_conn_rtp *conn, int payload_type, const char *audio_name, const struct mgcp_codec_param *param)
+{
+	const char *fmtp = NULL;
+	if (param && param->amr_octet_aligned_present)
+		fmtp = (param->amr_octet_aligned ? OSMO_SDP_STR_AMR_OCTET_ALIGN_1 : OSMO_SDP_STR_AMR_OCTET_ALIGN_0);
+
+	return mgcp_codec_add2(conn, payload_type, audio_name, fmtp);
+}
+
 bool mgcp_codec_amr_is_octet_aligned(const struct mgcp_rtp_codec *codec)
 {
-	if (!codec->param_present)
-		return false;
-	if (!codec->param.amr_octet_aligned_present)
-		return false;
-	return codec->param.amr_octet_aligned;
+	/* Legacy */
+	if (!codec->fmtp[0]
+	    && codec->param_present
+	    && codec->param.amr_octet_aligned_present)
+		return codec->param.amr_octet_aligned;
+
+	return osmo_sdp_fmtp_amr_is_octet_aligned(codec->fmtp);
 }
 
 /* Compare two codecs, all parameters must match up */
@@ -455,19 +473,29 @@ int mgcp_codec_decide(struct mgcp_conn_rtp *conn_src, struct mgcp_conn_rtp *conn
 		}
 	}
 
-	return -EINVAL;
+	if (conn_dst->end.codecs_assigned)
+		conn_dst->end.codec = &conn_dst->end.codecs[0];
+	else
+		return -EINVAL;
+
+	if (conn_src->end.codecs_assigned)
+		conn_src->end.codec = &conn_src->end.codecs[0];
+	else
+		return -EINVAL;
+
+	return 0;
 }
 
 /* Check if the codec has a specific AMR mode (octet-aligned or bandwith-efficient) set. */
 bool mgcp_codec_amr_align_mode_is_indicated(const struct mgcp_rtp_codec *codec)
 {
-	if (codec->param_present == false)
-		return false;
-	if (!codec->param.amr_octet_aligned_present)
-		return false;
-	if (strcmp(codec->subtype_name, "AMR") != 0)
-		return false;
-	return true;
+	if (!codec->fmtp[0]) {
+		/* Legacy */
+		return codec->param_present && codec->param.amr_octet_aligned_present;
+	}
+
+	/* Just check for presence, not the actual value. */
+	return osmo_sdp_fmtp_get_val(NULL, 0, codec->fmtp, OSMO_SDP_STR_AMR_OCTET_ALIGN);
 }
 
 /* Find the payload type number configured for a specific codec by SDP.

src/libosmo-mgcp/mgcp_network.c

@@ -1189,12 +1189,12 @@ int mgcp_send(struct mgcp_endpoint *endp, int is_rtp, struct osmo_sockaddr *addr
 			if (mgcp_conn_rtp_is_iuup(conn_dst) || mgcp_conn_rtp_is_iuup(conn_src)) {
 				/* the iuup code will correctly transform to the correct AMR mode */
 			} else if (mgcp_codec_amr_align_mode_is_indicated(conn_dst->end.codec)) {
-				rc = amr_oa_bwe_convert(endp, msg,
-							conn_dst->end.codec->param.amr_octet_aligned);
+				bool oa = mgcp_codec_amr_is_octet_aligned(conn_dst->end.codec);
+				rc = amr_oa_bwe_convert(endp, msg, oa);
 				if (rc < 0) {
 					LOGPENDP(endp, DRTP, LOGL_ERROR,
 						 "Error in AMR octet-aligned <-> bandwidth-efficient mode conversion (target=%s)\n",
-						 conn_dst->end.codec->param.amr_octet_aligned ? "octet-aligned" : "bandwidth-efficient");
+						 oa ? "octet-aligned" : "bandwidth-efficient");
 					break;
 				}
 			} else if (rtp_end->rfc5993_hr_convert &&
@@ -1505,16 +1505,18 @@ static int rx_rtp(struct msgb *msg)
 	if (mc->proto == MGCP_PROTO_RTP
 	    && conn_src->end.codec
 	    && mgcp_codec_amr_align_mode_is_indicated(conn_src->end.codec)) {
+		bool src_oa;
 		/* Make sure that the incoming AMR frame format matches the frame format that the call agent has
 		 * communicated via SDP when the connection was created/modfied. */
 		int oa = amr_oa_check((char*)msgb_data(msg), msgb_length(msg));
 		if (oa < 0)
 			return -1;
-		if (((bool)oa) != conn_src->end.codec->param.amr_octet_aligned) {
+		src_oa = mgcp_codec_amr_is_octet_aligned(conn_src->end.codec);
+		if (((bool)oa) != src_oa) {
 			LOG_CONN_RTP(conn_src, LOGL_NOTICE,
 				     "rx_rtp(%u bytes): Expected RTP AMR octet-aligned=%u but got octet-aligned=%u."
 				     " check the config of your call-agent!\n",
-				     msgb_length(msg), conn_src->end.codec->param.amr_octet_aligned, oa);
+				     msgb_length(msg), src_oa, oa);
 			return -1;
 		}
 	}

src/libosmo-mgcp/mgcp_protocol.c

@@ -1131,6 +1131,7 @@ mgcp_header_done:
 
 	LOGPCONN(_conn, DLMGCP, LOGL_NOTICE,
 		 "CRCX: connection successfully created\n");
+
 	rate_ctr_inc(rate_ctr_group_get_ctr(rate_ctrs, MGCP_CRCX_SUCCESS));
 	mgcp_endp_update(endp);
 

src/libosmo-mgcp/mgcp_sdp.c

@@ -35,6 +35,9 @@
 #include <osmocom/mgcp/mgcp_sdp.h>
 #include <osmocom/mgcp/mgcp_protocol.h>
 
+#include <osmocom/sdp/fmtp.h>
+#include <osmocom/sdp/sdp_strings.h>
+
 #include <errno.h>
 #include <stdlib.h>
 #include <limits.h>
@@ -55,7 +58,7 @@ struct sdp_rtp_map {
 };
 struct sdp_fmtp_param {
 	int payload_type;
-	struct mgcp_codec_param param;
+	const char *fmtp;
 };
 
 
@@ -195,11 +198,7 @@ static int fmtp_from_sdp(void *ctx, struct sdp_fmtp_param *fmtp_param, char *sdp
 {
 	char *str;
 	char *str_ptr;
-	char *param_str;
 	unsigned int pt;
-	unsigned int count = 0;
-	char delimiter;
-	unsigned int amr_octet_aligned;
 
 	memset(fmtp_param, 0, sizeof(*fmtp_param));
 
@@ -218,40 +217,13 @@ static int fmtp_from_sdp(void *ctx, struct sdp_fmtp_param *fmtp_param, char *sdp
 		goto error;
 	fmtp_param->payload_type = pt;
 
-	/* Advance pointer to the beginning of the parameter section and
-	 * tokenize string */
+	/* Advance pointer to the beginning of the parameter section */
 	str_ptr = strstr(str_ptr, " ");
 	if (!str_ptr)
 		goto error;
 	str_ptr++;
 
-	param_str = strtok(str_ptr, " ");
-	if (!param_str)
-		goto exit;
-
-	while (1) {
-		/* Make sure that we don't get trapped in an endless loop */
-		if (count > 256)
-			goto error;
-
-		/* Chop off delimiters ';' at the end */
-		delimiter = str_ptr[strlen(str_ptr) - 1];
-		if (delimiter == ';' || delimiter == ',')
-			str_ptr[strlen(str_ptr) - 1] = '\0';
-
-		/* AMR octet aligned parameter (see also RFC 3267, section 8.3) */
-		if (sscanf(param_str, "octet-align=%d", &amr_octet_aligned) == 1) {
-			fmtp_param->param.amr_octet_aligned_present = true;
-			fmtp_param->param.amr_octet_aligned = false;
-			if (amr_octet_aligned == 1)
-				fmtp_param->param.amr_octet_aligned = true;
-		}
-
-		param_str = strtok(NULL, " ");
-		if (!param_str)
-			break;
-		count++;
-	}
+	fmtp_param->fmtp = talloc_strdup(ctx, str_ptr);
 
 exit:
 	talloc_free(str);
@@ -299,13 +271,13 @@ static int audio_ip_from_sdp(struct osmo_sockaddr *dst_addr, char *sdp)
 
 /* Pick optional fmtp parameters by payload type, if there are no fmtp
  * parameters, a nullpointer is returned */
-static struct mgcp_codec_param *param_by_pt(int pt, struct sdp_fmtp_param *fmtp_params, unsigned int fmtp_params_len)
+static const char *param_by_pt(int pt, struct sdp_fmtp_param *fmtp_params, unsigned int fmtp_params_len)
 {
 	unsigned int i;
 
 	for (i = 0; i < fmtp_params_len; i++) {
 		if (fmtp_params[i].payload_type == pt)
-			return &fmtp_params[i].param;
+			return fmtp_params[i].fmtp;
 	}
 
 	return NULL;
@@ -326,7 +298,6 @@ int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 	unsigned int codecs_used = 0;
 	struct sdp_fmtp_param fmtp_params[MGCP_MAX_CODECS];
 	unsigned int fmtp_used = 0;
-	struct mgcp_codec_param *codec_param;
 	char ipbuf[INET6_ADDRSTRLEN];
 	char *line;
 	unsigned int i;
@@ -421,8 +392,8 @@ int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 
 	/* Store parsed codec information */
 	for (i = 0; i < codecs_used; i++) {
-		codec_param = param_by_pt(codecs[i].payload_type, fmtp_params, fmtp_used);
-		rc = mgcp_codec_add(conn, codecs[i].payload_type, codecs[i].map_line, codec_param);
+		const char *fmtp = param_by_pt(codecs[i].payload_type, fmtp_params, fmtp_used);
+		rc = mgcp_codec_add2(conn, codecs[i].payload_type, codecs[i].map_line, fmtp);
 		if (rc < 0)
 			LOGPENDP(endp, DLMGCP, LOGL_NOTICE, "failed to add codec\n");
 	}
@@ -436,10 +407,12 @@ int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp,
 	if (codecs_used == 0)
 		LOGPC(DLMGCP, LOGL_NOTICE, "none");
 	for (i = 0; i < codecs_used; i++) {
-		LOGPC(DLMGCP, LOGL_NOTICE, "%d=%s",
+		LOGPC(DLMGCP, LOGL_NOTICE, " %d=%s%s%s%s",
 		      rtp->codecs[i].payload_type,
-		      strlen(rtp->codecs[i].subtype_name) ? rtp->codecs[i].subtype_name : "unknown");
-		LOGPC(DLMGCP, LOGL_NOTICE, " ");
+		      strlen(rtp->codecs[i].subtype_name) ? rtp->codecs[i].subtype_name : "unknown",
+		      rtp->codecs[i].fmtp[0] ? ",fmtp='" : "",
+		      rtp->codecs[i].fmtp,
+		      rtp->codecs[i].fmtp[0] ? "'" : "");
 	}
 	LOGPC(DLMGCP, LOGL_NOTICE, "\n");
 
@@ -494,18 +467,15 @@ static int add_fmtp(struct msgb *sdp, struct sdp_fmtp_param *fmtp_params, unsign
 	int rc;
 
 	for (i = 0; i < fmtp_params_len; i++) {
+		bool first = true;
 		rc = msgb_printf(sdp, "a=fmtp:%u", fmtp_params[i].payload_type);
 		if (rc < 0)
 			return -EINVAL;
 
 		/* Add amr octet align parameter */
-		if (fmtp_params[i].param.amr_octet_aligned_present) {
-			if (fmtp_params[i].param.amr_octet_aligned)
-				rc = msgb_printf(sdp, " octet-align=1");
-			else
-				rc = msgb_printf(sdp, " octet-align=0");
-			if (rc < 0)
-				return -EINVAL;
+		if (fmtp_params[i].fmtp) {
+			msgb_printf(sdp, "%s%s", first ? " " : ";", fmtp_params[i].fmtp);
+			first = false;
 		}
 
 		rc = msgb_printf(sdp, "\r\n");
@@ -529,7 +499,6 @@ int mgcp_write_response_sdp(const struct mgcp_endpoint *endp,
 	const struct mgcp_rtp_codec *codec;
 	const char *audio_name;
 	int payload_type;
-	struct sdp_fmtp_param fmtp_param;
 	int rc;
 	int payload_types[1];
 	int local_port;
@@ -578,12 +547,22 @@ int mgcp_write_response_sdp(const struct mgcp_endpoint *endp,
 				goto buffer_too_small;
 		}
 
-		if (codec->param_present) {
-			fmtp_param.payload_type = payload_type;
-			fmtp_param.param = codec->param;
-			fmtp_params[0] = fmtp_param;
+		if (codec->fmtp[0]) {
+			fmtp_params[0] = (struct sdp_fmtp_param){
+				.payload_type = payload_type,
+				.fmtp = codec->fmtp,
+			};
 			fmtp_params_len = 1;
+		} else if (codec->param_present) {
+			/* Legacy */
+			fmtp_params[0] = (struct sdp_fmtp_param){
+				.payload_type = payload_type,
+			};
+			fmtp_params_len = 1;
+			fmtp_params[0].fmtp = (codec->param.amr_octet_aligned ?
+					       OSMO_SDP_STR_AMR_OCTET_ALIGN_1 : OSMO_SDP_STR_AMR_OCTET_ALIGN_0);
 		}
+
 		rc = add_fmtp(sdp, fmtp_params, fmtp_params_len);
 		if (rc < 0)
 			goto buffer_too_small;

src/libosmo-sdp/Makefile.am

@@ -0,0 +1,24 @@
+AM_CPPFLAGS = \
+	$(all_includes) \
+	-I$(top_srcdir)/include \
+	-I$(top_builddir) \
+	$(NULL)
+
+AM_CFLAGS = \
+	-Wall \
+	$(LIBOSMOCORE_CFLAGS) \
+	$(TALLOC_CFLAGS) \
+	$(NULL)
+
+noinst_LTLIBRARIES = \
+	libosmo-sdp.la \
+	$(NULL)
+
+libosmo_sdp_la_SOURCES = \
+	fmtp.c \
+	$(NULL)
+
+libosmo_sdp_la_LIBADD = \
+	$(LIBOSMOCORE_LIBS) \
+	$(TALLOC_LIBS) \
+	$(NULL)

src/libosmo-sdp/fmtp.c

@@ -0,0 +1,150 @@
+/*
+ * (C) 2023-2024 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Neels Hofmeyr
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#include <string.h>
+#include <ctype.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/logging.h>
+
+#include <osmocom/sdp/sdp_strings.h>
+#include <osmocom/sdp/fmtp.h>
+
+/* End of current fmtp parameter. Return a pointer to the next ';' character, if present, or the terminating '\0'. */
+static const char *osmo_sdp_fmtp_end(const char *fmtp)
+{
+	if (!fmtp)
+		return NULL;
+	for (; *fmtp && *fmtp != ';'; fmtp++);
+	return fmtp;
+}
+
+/* Start of next fmtp parameter. Return a pointer to the first character of the next fmtp parameter's name, or the
+ * terminating '\0'. */
+static const char *osmo_sdp_fmtp_next(const char *fmtp)
+{
+	if (!fmtp)
+		return NULL;
+	fmtp = osmo_sdp_fmtp_end(fmtp);
+	for (; *fmtp && (*fmtp == ';' || isspace(*fmtp)); fmtp++);
+	return fmtp;
+}
+
+/*! Parse a given SDP fmtp value string, returning the value of a specific option, if present.
+ *
+ * Example:
+ *
+ *   const char *fmtp_vals = "octet-align=1;mode-set=0,2,4,7";
+ *
+ *   char mode_set_str[23];
+ *   if (osmo_sdp_fmtp_get_val(mode_set_str, sizeof(mode_set_str), fmtp_vals, "mode-set")) {
+ *           // option 'mode-set' is present, now mode_set_str == "0,2,4,7"
+ *           use_modeset(mode_set_str);
+ *   } else {
+ *           // if 'mode-set' were not present...
+ *           use_modeset(MY_DEFAULT_MODESET);
+ *   }
+ *
+ * \param[out] val  Buffer to write the option's value to.
+ * \param[in] val_size  Space available in val.
+ * \param[in] fmtp  fmtp value string to parse -- must not contain the "a=fmtp:N " prefix, only the value part.
+ * \param[in] option_name  Which fmtp option to get the value for.
+ * \return true when the option was found, false when it was not present.
+ */
+bool osmo_sdp_fmtp_get_val(char *val, size_t val_size, const char *fmtp, const char *option_name)
+{
+	const char *pos = fmtp;
+	const char *end;
+	int option_name_len = strlen(option_name);
+	for (; pos && *pos; pos = osmo_sdp_fmtp_next(pos)) {
+		if (!osmo_str_startswith(pos, option_name))
+			continue;
+		pos += option_name_len;
+		if (*pos != '=')
+			continue;
+		pos++;
+		break;
+	}
+
+	if (!pos || !*pos)
+		return false;
+
+	end = osmo_sdp_fmtp_end(pos);
+	OSMO_ASSERT(end);
+	if (val && val_size)
+		osmo_strlcpy(val, pos, OSMO_MIN(val_size, end - pos + 1));
+	return true;
+}
+
+/*! Parse a given SDP fmtp value string, returning the value of a specific integer option, if present.
+ *
+ * Example:
+ *
+ *   const char *fmtp_vals = "octet-align=1;mode-set=0,2,4,7";
+ *   bool oa = osmo_sdp_fmtp_get_int(fmtp_vals, OSMO_SDP_AMR_OCTET_ALIGN_NAME, 1);
+ *
+ * \param[in] fmtp  fmtp value string to parse -- must not contain the "a=fmtp:N " prefix, only the value part.
+ * \param[in] option_name  Which fmtp option to get the value for.
+ * \param[in] default_value  If option_name is not present or cannot be parsed as integer, return this instead.
+ * \return the integer value when the option was found and actually an integer, default_value otherwise.
+ */
+int64_t osmo_sdp_fmtp_get_int(const char *fmtp, const char *option_name, int64_t default_value)
+{
+	char val[128];
+	if (!osmo_sdp_fmtp_get_val(val, sizeof(val), fmtp, option_name))
+		return default_value;
+	if (!val[0])
+		return default_value;
+	int64_t i;
+	if (osmo_str_to_int64(&i, val, 10, INT64_MIN, INT64_MAX)) {
+		/* error parsing number */
+		return default_value;
+	}
+	return i;
+}
+
+/*! Return true if octet-align is present and set to 1 in the given AMR related fmtp value.
+ * Default to octet-align=0, i.e. bandwidth-efficient mode.
+ *
+ * See RFC4867 "RTP Payload Format for AMR and AMR-WB" sections "8.1. AMR Media Type Registration" and "8.2. AMR-WB
+ * Media Type Registration":
+ *
+ *    octet-align: Permissible values are 0 and 1.  If 1, octet-align
+ *                 operation SHALL be used.  If 0 or if not present,
+ *                 bandwidth-efficient operation is employed.
+ *
+ * https://tools.ietf.org/html/rfc4867
+ */
+bool osmo_sdp_fmtp_amr_is_octet_aligned(const char *fmtp)
+{
+	return osmo_sdp_fmtp_get_int(fmtp, OSMO_SDP_STR_AMR_OCTET_ALIGN, 0) == 1;
+}
+
+static void strip_whitespace(char *str)
+{
+	char *i = str;
+	char *o = str;
+	for (; *i; i++, o++) {
+		while (isspace(*i))
+			i++;
+		*o = *i;
+		if (!*i)
+			break;
+	}
+}

src/osmo-mgw/Makefile.am

@@ -25,12 +25,6 @@ osmo_mgw_SOURCES = \
 	$(NULL)
 
 osmo_mgw_LDADD = \
-	$(top_builddir)/src/libosmo-mgcp/libosmo-mgcp.a \
-	$(LIBOSMOCORE_LIBS) \
-	$(LIBOSMOVTY_LIBS) \
-	$(LIBOSMOGSM_LIBS) \
+	$(top_builddir)/src/libosmo-mgcp/libosmo-mgcp.la \
 	$(LIBOSMOCTRL_LIBS) \
-	$(LIBOSMONETIF_LIBS) \
-	$(LIBOSMOABIS_LIBS) \
-	$(LIBOSMOTRAU_LIBS) \
 	$(NULL)

tests/Makefile.am

@@ -1,6 +1,7 @@
 SUBDIRS = \
 	mgcp_client \
 	mgcp \
+	sdp \
 	$(NULL)
 
 # The `:;' works around a Bash 3.2 bug when the output is not writeable.

tests/mgcp/Makefile.am

@@ -34,7 +34,7 @@ mgcp_test_SOURCES = \
 	$(NULL)
 
 mgcp_test_LDADD = \
-	$(top_builddir)/src/libosmo-mgcp/libosmo-mgcp.a \
+	$(top_builddir)/src/libosmo-mgcp/libosmo-mgcp.la \
 	$(LIBOSMOCORE_LIBS) \
 	$(LIBOSMOVTY_LIBS) \
 	$(LIBOSMOGSM_LIBS) \

tests/mgcp/mgcp_test.c

@@ -550,7 +550,7 @@ static void test_strline(void)
 	"t=0 0\r\n" \
 	"m=audio 16012 RTP/AVP 111\r\n" \
 	"a=rtpmap:111 AMR/8000/1\r\n" \
-	"a=fmtp:111 octet-align=1\r\n" \
+	"a=fmtp:111 mode-change-capability=2; octet-align=1\r\n" \
 	"a=ptime:20\r\n"
 
 #define CRCX_NO_LCO_NO_SDP_RET \
@@ -838,6 +838,7 @@ static void test_messages(void)
 			}
 		} else if (check_response(msg->data, t->exp_resp) != 0) {
 			printf("%s failed.\n", t->name);
+			fflush(stdout);
 			OSMO_ASSERT(false);
 		}
 

tests/sdp/Makefile.am

@@ -0,0 +1,38 @@
+AM_CPPFLAGS = \
+	$(all_includes) \
+	-I$(top_srcdir)/include \
+	-I$(top_builddir)/include \
+	-I$(top_srcdir) \
+	$(NULL)
+
+AM_CFLAGS = \
+	-Wall \
+	-ggdb3 \
+	$(LIBOSMOCORE_CFLAGS) \
+	$(COVERAGE_CFLAGS) \
+	$(NULL)
+
+AM_LDFLAGS = \
+	$(COVERAGE_LDFLAGS) \
+	-no-install \
+	$(NULL)
+
+EXTRA_DIST = \
+	sdp_fmtp_test.ok \
+	sdp_fmtp_test.err \
+	$(NULL)
+
+check_PROGRAMS = \
+	sdp_fmtp_test \
+	$(NULL)
+
+sdp_fmtp_test_SOURCES = \
+	sdp_fmtp_test.c \
+	$(NULL)
+
+sdp_fmtp_test_LDADD = \
+	$(top_builddir)/src/libosmo-sdp/libosmo-sdp.la \
+	$(NULL)
+
+update_exp:
+	$(builddir)/sdp_fmtp_test >$(srcdir)/sdp_fmtp_test.ok 2>$(srcdir)/sdp_fmtp_test.err

tests/sdp/sdp_fmtp_test.c

@@ -0,0 +1,126 @@
+#include <inttypes.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/application.h>
+#include <osmocom/core/logging.h>
+
+#include <osmocom/sdp/fmtp.h>
+
+struct get_val_test {
+	const char *fmtp_string;
+	const char *val_name;
+	bool expect_rc;
+	const char *expect_val;
+};
+
+const struct get_val_test get_val_tests[] = {
+	{
+		"foo=123;bar=success;baz=456", "foo",
+		true, "123"
+	},
+	{
+		"foo=123;bar=success;baz=456", "bar",
+		true, "success"
+	},
+	{
+		"foo=123;bar=success;baz=456", "baz",
+		true, "456"
+	},
+};
+
+void test_get_val(void)
+{
+	int i;
+	printf("\n--- %s()\n", __func__);
+
+	for (i = 0; i < ARRAY_SIZE(get_val_tests); i++) {
+		const struct get_val_test *t = &get_val_tests[i];
+		char val[128] = {};
+		bool rc = osmo_sdp_fmtp_get_val(val, sizeof(val), t->fmtp_string, t->val_name);
+		bool ok;
+		printf("osmo_sdp_fmtp_get_val('%s', '%s') rc=%s",
+		       t->fmtp_string, t->val_name,
+		       rc ? "true" : "false");
+		if (rc)
+			printf(" val='%s'", val);
+		ok = true;
+		if (rc != t->expect_rc) {
+			printf(" ERROR: expected rc=%s", t->expect_rc ? "true" : "false");
+			ok = false;
+		}
+		if (t->expect_val && strcmp(val, t->expect_val)) {
+			printf(" ERROR: expected val='%s'", t->expect_val);
+			ok = false;
+		}
+		if (ok)
+			printf(" ok");
+		printf("\n");
+	}
+	printf("\n--- %s() DONE\n", __func__);
+}
+
+struct get_int_test {
+	const char *fmtp_string;
+	const char *val_name;
+	int64_t defval;
+	int64_t expect_rc;
+};
+
+const struct get_int_test get_int_tests[] = {
+	{
+		"foo=123;bar=success;baz=456", "foo", -1,
+		123
+	},
+	{
+		"foo=123;bar=success;baz=456", "bar", -1,
+		-1
+	},
+	{
+		"foo=123;bar=success;baz=456", "baz", -1,
+		456
+	},
+};
+
+void test_get_int(void)
+{
+	int i;
+	printf("\n--- %s()\n", __func__);
+
+	for (i = 0; i < ARRAY_SIZE(get_int_tests); i++) {
+		const struct get_int_test *t = &get_int_tests[i];
+		int64_t rc = osmo_sdp_fmtp_get_int(t->fmtp_string, t->val_name, t->defval);
+		printf("osmo_sdp_fmtp_get_int('%s', '%s') rc=%"PRId64,
+		       t->fmtp_string, t->val_name, rc);
+		if (rc != t->expect_rc) {
+			printf(" ERROR: expected rc=%"PRId64, t->expect_rc);
+		}
+		else {
+			printf(" ok");
+		}
+		printf("\n");
+	}
+	printf("\n--- %s() DONE\n", __func__);
+}
+
+static const struct log_info_cat log_categories[] = {
+};
+
+const struct log_info log_info = {
+        .cat = log_categories,
+        .num_cat = ARRAY_SIZE(log_categories),
+};
+
+int main(void)
+{
+	void *ctx = talloc_named_const(NULL, 1, "sdp_fmtp_test");
+
+	osmo_init_logging2(ctx, &log_info);
+	log_set_print_filename2(osmo_stderr_target, LOG_FILENAME_NONE);
+	log_set_print_timestamp(osmo_stderr_target, 0);
+	log_set_use_color(osmo_stderr_target, 0);
+	log_set_print_category_hex(osmo_stderr_target, 0);
+	log_set_print_category(osmo_stderr_target, 1);
+
+	test_get_val();
+	test_get_int();
+	return 0;
+}

tests/sdp/sdp_fmtp_test.ok

@@ -0,0 +1,14 @@
+
+--- test_get_val()
+osmo_sdp_fmtp_get_val('foo=123;bar=success;baz=456', 'foo') rc=true val='123' ok
+osmo_sdp_fmtp_get_val('foo=123;bar=success;baz=456', 'bar') rc=true val='success' ok
+osmo_sdp_fmtp_get_val('foo=123;bar=success;baz=456', 'baz') rc=true val='456' ok
+
+--- test_get_val() DONE
+
+--- test_get_int()
+osmo_sdp_fmtp_get_int('foo=123;bar=success;baz=456', 'foo') rc=123 ok
+osmo_sdp_fmtp_get_int('foo=123;bar=success;baz=456', 'bar') rc=-1 ok
+osmo_sdp_fmtp_get_int('foo=123;bar=success;baz=456', 'baz') rc=456 ok
+
+--- test_get_int() DONE

tests/testsuite.at

@@ -13,3 +13,10 @@ AT_KEYWORDS([mgcp])
 cat $abs_srcdir/mgcp/mgcp_test.ok > expout
 AT_CHECK([$abs_top_builddir/tests/mgcp/mgcp_test], [], [expout], [ignore])
 AT_CLEANUP
+
+AT_SETUP([sdp_fmtp])
+AT_KEYWORDS([sdp_fmtp])
+cat $abs_srcdir/sdp/sdp_fmtp_test.ok > expout
+cat $abs_srcdir/sdp/sdp_fmtp_test.err > experr
+AT_CHECK([$abs_top_builddir/tests/sdp/sdp_fmtp_test], [], [expout], [experr])
+AT_CLEANUP