debian/postinst: add checks, be verbose

Do not attempt to change permissions/ownership if the package gets
upgraded from a version higher than the next release.

Do not fail if the user deleted the config file.

Be verbose when changing permissions.

Related: OS#4107
Change-Id: I2b01a7625cf66fbb7d203f939ddcc1cbab43cf33

.gitignore

@@ -5,6 +5,7 @@ Makefile
 .deps
 *.sw?
 .version
+*~
 
 aclocal.m4
 autom4te.cache
@@ -33,3 +34,5 @@ doc/manuals/generated/
 doc/manuals/osmomsc-usermanual.xml
 doc/manuals/common
 doc/manuals/build
+
+contrib/osmo-sip-connector.spec

Makefile.am

@@ -3,7 +3,13 @@ AUTOMAKE_OPTIONS = foreign dist-bzip2 1.6
 SUBDIRS = src tests contrib doc
 
 BUILT_SOURCES = $(top_srcdir)/.version
-EXTRA_DIST = git-version-gen osmoappdesc.py .version
+EXTRA_DIST = \
+	     .version \
+	     README.md \
+	     debian \
+	     git-version-gen \
+	     osmoappdesc.py \
+	     $(NULL)
 
 AM_DISTCHECK_CONFIGURE_FLAGS = \
 	--with-systemdsystemunitdir=$$dc_install_base/$(systemdsystemunitdir)

README.asciidoc

@@ -1,34 +0,0 @@
-Osmo SIP Connector
-==================
-
-Simple utility to map MNCC to SIP and SIP to MNCC. The VTY interface
-can be used to make configurations. The code doesn't have any RTP or
-transcoding support.
-
-Call identities can be either the MSISDN or the IMSI of the subscriber.
-
-
-Requirements of Equipment
-^^^^^^^^^^^^^^^^^^^^^^^^^
-
-* DTMF need to be sent using SIP INFO messages. DTMF in RTP is not
-supported.
-
-* BTS+PBX and SIP connector+PBX  must be in the same network (UDP must be
-able to flow directly between these elements)
-
-* No handover support.
-
-* IP based BTS (e.g. Sysmocom sysmoBTS but no Siemens BS11)
-
-* No emergency calls
-
-Limitations
-^^^^^^^^^^^
-
-* PT of RTP needs to match the one used by the BTS. E.g. AMR needs to use
-the same PT as the BTS. This is because rtp_payload2 is not yet supported
-by the osmo-bts software.
-
-* AMR SDP file doesn't include the mode-set params and allowed codec modes.
-This needs to be configured in some way.

README.md

@@ -0,0 +1,82 @@
+osmo-sip-connector - Osmocom SIP connector
+==========================================
+
+This implements an interface between the MNCC (Mobile Network Call Control)
+interface of OsmoMSC (and also previously OsmoNITB) and SIP.
+
+Call identities can be either the MSISDN or the IMSI of the subscriber.
+
+Requirements of Equipment
+-------------------------
+
+* DTMF need to be sent using SIP INFO messages. DTMF in RTP is not
+supported.
+* BTS+PBX and SIP connector+PBX  must be in the same network (UDP must be
+able to flow directly between these elements)
+* No handover support.
+* IP based BTS (e.g. Sysmocom sysmoBTS but no Siemens BS11)
+* No emergency calls
+
+Limitations
+-----------
+
+* PT of RTP needs to match the one used by the BTS. E.g. AMR needs to use
+the same PT as the BTS. This is because rtp_payload2 is not yet supported
+by the osmo-bts software.
+
+* AMR SDP file doesn't include the mode-set params and allowed codec modes.
+This needs to be configured in some way.
+
+Homepage
+--------
+
+You can find the osmo-sip-connector issue tracker and wiki online at
+<https://osmocom.org/projects/osmo-sip-conector> and <https://osmocom.org/projects/osmo-sip-conector/wiki>
+
+
+GIT Repository
+--------------
+
+You can clone from the official osmo-msc.git repository using
+
+        git clone https://gitea.osmocom.org/cellular-infrastructure/osmo-sip-connector
+
+There is a web interface at <https://gitea.osmocom.org/cellular-infrastructure/osmo-sip-connector>
+
+
+Documentation
+-------------
+
+User Manuals and VTY reference manuals are [optionally] built in PDF form
+as part of the build process.
+
+Pre-rendered PDF version of the current "master" can be found at
+[User Manual](https://downloads.osmocom.org/docs/latest/osmosipconnector-usermanual.pdf)
+as well as the [VTY Reference Manual](https://downloads.osmocom.org/docs/latest/osmosipconnector-vty-reference.pdf)
+
+
+Mailing List
+------------
+
+Discussions related to osmo-sip-connector are happening on the
+openbsc@lists.osmocom.org mailing list, please see
+<https://lists.osmocom.org/mailman/listinfo/openbsc> for subscription
+options and the list archive.
+
+Please observe the [Osmocom Mailing List
+Rules](https://osmocom.org/projects/cellular-infrastructure/wiki/Mailing_List_Rules)
+when posting.
+
+Contributing
+------------
+
+Our coding standards are described at
+<https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards>
+
+We us a gerrit based patch submission/review process for managing
+contributions.  Please see
+<https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit> for
+more details
+
+The current patch queue for osmo-sip-connector can be seen at
+<https://gerrit.osmocom.org/#/q/project:osmo-sip-connector+status:open>

TODO-RELEASE

@@ -0,0 +1,9 @@
+# When cleaning up this file: bump API version in corresponding Makefile.am and rename corresponding debian/lib*.install
+# according to https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html#Updating-version-info
+# In short:
+# LIBVERSION=c:r:a
+# If the library source code has changed at all since the last update, then increment revision: c:r + 1:a.
+# If any interfaces have been added, removed, or changed since the last update: c + 1:0:0.
+# If any interfaces have been added since the last public release: c:r:a + 1.
+# If any interfaces have been removed or changed since the last public release: c:r:0.
+#library	what	        description / commit summary line

configure.ac

@@ -18,13 +18,15 @@ dnl include release helper
 RELMAKE='-include osmo-release.mk'
 AC_SUBST([RELMAKE])
 
+CFLAGS="$CFLAGS -std=gnu11"
+
 dnl kernel style compile messages
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 AC_PROG_CC
 
-PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore >= 1.0.0)
-PKG_CHECK_MODULES(LIBOSMOGSM, libosmogsm >= 1.0.0)
-PKG_CHECK_MODULES(LIBOSMOVTY, libosmovty >= 1.0.0)
+PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore >= 1.9.0)
+PKG_CHECK_MODULES(LIBOSMOGSM, libosmogsm >= 1.9.0)
+PKG_CHECK_MODULES(LIBOSMOVTY, libosmovty >= 1.9.0)
 PKG_CHECK_MODULES(SOFIASIP, sofia-sip-ua-glib >= 1.12.0)
 
 AC_ARG_ENABLE(sanitize,

contrib/jenkins.sh

@@ -28,7 +28,6 @@ export PATH="$inst/bin:$PATH"
 # Additional configure options and depends
 CONFIG=""
 if [ "$WITH_MANUALS" = "1" ]; then
-	osmo-build-dep.sh osmo-gsm-manuals
 	CONFIG="--enable-manuals"
 fi
 
@@ -45,12 +44,12 @@ autoreconf --install --force
 $MAKE $PARALLEL_MAKE
 $MAKE check \
   || cat-testlogs.sh
-DISTCHECK_CONFIGURE_FLAGS="$CONFIG" $MAKE distcheck \
+DISTCHECK_CONFIGURE_FLAGS="$CONFIG" $MAKE $PARALLEL_MAKE distcheck \
   || cat-testlogs.sh
 
 if [ "$WITH_MANUALS" = "1" ] && [ "$PUBLISH" = "1" ]; then
 	make -C "$base/doc/manuals" publish
 fi
 
-$MAKE maintainer-clean
+$MAKE $PARALLEL_MAKE maintainer-clean
 osmo-clean-workspace.sh

contrib/systemd/osmo-sip-connector.service

@@ -1,9 +1,15 @@
 [Unit]
 Description=Osmo SIP Connector
+After=network-online.target
+Wants=network-online.target
 
 [Service]
 Type=simple
 Restart=always
+StateDirectory=osmocom
+WorkingDirectory=%S/osmocom
+User=osmocom
+Group=osmocom
 ExecStart=/usr/bin/osmo-sip-connector -c /etc/osmocom/osmo-sip-connector.cfg
 RestartSec=2
 

contrib/testpbx/Makefile

@@ -4,9 +4,9 @@ container:
 	docker build -t osmo-freeswitch-pbx:latest .
 
 run:
-	docker run -it --name=osmo-freeswitch-pbx \
+	docker run --rm -it --name=osmo-freeswitch-pbx \
 		-p 5060:5060/udp -p 6000-6020:6000-6020/udp \
-		--rm=true osmo-freeswitch-pbx:latest
+		osmo-freeswitch-pbx:latest
 
 stop:
 	docker rm -f osmo-freeswitch-pbx

contrib/testpbx/README

@@ -24,6 +24,6 @@ Build:
 
 Run:
 
-	docker run yourimagename:tag
+	docker run --rm yourimagename:tag
 
 SIP is exposed on 5060 of your port and audio on 6000-6020

debian/changelog

@@ -1,3 +1,125 @@
+osmo-sip-connector (1.6.3) unstable; urgency=medium
+
+  [ arehbein ]
+  * Transition to use of 'telnet_init_default'
+
+  [ Harald Welte ]
+  * doc: fix typo
+  * doc: Expand the virtually empty user manual with some basics
+
+  [ Oliver Smith ]
+  * sip: tweak log for release caused by status >= 300
+  * debian: set compat level to 10
+
+  [ Vadim Yanitskiy ]
+  * tests: $(BUILT_SOURCES) is not defined, depend on osmo-sip-connector
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 12 Sep 2023 17:24:26 +0200
+
+osmo-sip-connector (1.6.2) unstable; urgency=medium
+
+  [ Max ]
+  * Set working directory in systemd service file
+
+  [ Keith Whyte ]
+  * Set MNCC_F_GCR field when the gcr is present
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 07 Feb 2023 17:47:28 +0100
+
+osmo-sip-connector (1.6.1) unstable; urgency=medium
+
+  [ Pau Espin Pedrol ]
+  * Add TODO-RELEASE
+
+  [ Harald Welte ]
+  * update git URLs (git -> https; gitea)
+  * Convert + Expand README file
+
+  [ Oliver Smith ]
+  * contrib/testpbx: fix docker run --rm linter error
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 28 Jun 2022 18:29:48 +0200
+
+osmo-sip-connector (1.6.0) unstable; urgency=medium
+
+  [ Neels Hofmeyr ]
+  * fix use-after-free in SIP re-INVITE
+  * SIP re-INVITE: fix media connection change detection
+  * SIP re-INVITE: log media connection
+
+  [ Oliver Smith ]
+  * debian/control: remove dh-systemd build-depend
+
+  [ Keith ]
+  * MNCC v8: Implement Basic Support for Global Call Reference.
+
+  [ Vadim Yanitskiy ]
+  * sip: fix memory leak (x_gcr) in send_invite()
+  * sip: use osmo_{enc,dec}_gcr() from libosmocore
+  * mncc: rework passing GCR over the MNCC interface
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 16 Nov 2021 14:52:09 +0100
+
+osmo-sip-connector (1.5.0) unstable; urgency=medium
+
+  [ Vadim Yanitskiy ]
+  * debian/control: change maintainer to the Osmocom team / mailing list
+
+  [ Matt Johnson ]
+  * sip: Specify invite contact tag
+
+  [ Alexander Couzens ]
+  * Revert "sip: Specify invite contact tag"
+  * mncc: remove callref argument from mncc_write()
+  * mncc: add return code for write/send function
+  * mncc: Introduce mncc_rtp_write similiar to mncc_write
+  * mncc: mncc_create_remote_leg: use mncc_write instead of write direct to the fd
+
+  [ Pau Espin Pedrol ]
+  * mncc: Support IPv6 addresses (new version mncc 7)
+  * sdp: Don't select addresses failing to parse
+  * contrib/jenkins: Enable parallel make in make distcheck
+  * mncc: Log write error code
+  * .gitignore: Get rid of new autofoo tmp files
+  * mncc: Fix write len
+
+  [ Oliver Smith ]
+  * contrib/jenkins: don't build osmo-gsm-manuals
+  * configure.ac: set -std=gnu11
+
+ -- Pau Espin Pedrol <pespin@espeweb.net>  Tue, 23 Feb 2021 13:42:08 +0100
+
+osmo-sip-connector (1.4.1) unstable; urgency=medium
+
+  [ Oliver Smith ]
+  * contrib: import RPM spec
+  * contrib: integrate RPM spec
+  * Makefile.am: EXTRA_DIST: debian, contrib/*.spec.in
+
+ -- Harald Welte <laforge@osmocom.org>  Thu, 13 Aug 2020 12:38:16 +0200
+
+osmo-sip-connector (1.4.0) unstable; urgency=medium
+
+  [ Keith ]
+  * coverity: Address issue found by coverity
+
+  [ Philipp Maier ]
+  * mncc: check fd before closing a connection
+
+  [ Alexander Couzens ]
+  * .service: require to ran after network-online.target
+  * exit if the sip agent failed to start
+
+  [ Oliver Smith ]
+  * mncc.c: fix gsm_mncc_rtp size checks
+  * osmoappdesc.py: switch to python 3
+
+  [ Neels Hofmeyr ]
+  * MNCC v6: add optional SDP to the socket protocol
+  * logging from sofia: add missing newline
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Thu, 02 Jan 2020 21:35:01 +0100
+
 osmo-sip-connector (1.3.0) unstable; urgency=medium
 
   [ Keith ]

debian/compat

@@ -1 +1 @@
-7
+10

debian/control

@@ -1,20 +1,19 @@
 Source: osmo-sip-connector
 Section: net
 Priority: optional
-Maintainer: Holger Hans Peter Freyther <holger@moiji-mobile.com>
-Build-Depends: debhelper (>= 7.0.0~),
+Maintainer: Osmocom team <openbsc@lists.osmocom.org>
+Build-Depends: debhelper (>= 10),
                autotools-dev,
                pkg-config,
                libsofia-sip-ua-glib-dev,
                libsofia-sip-ua-dev,
-               dh-systemd (>= 1.5),
                dh-autoreconf,
-               libosmocore-dev (>= 1.0.0),
-               osmo-gsm-manuals-dev
+               libosmocore-dev (>= 1.9.0),
+               osmo-gsm-manuals-dev (>= 1.5.0)
 Standards-Version: 3.8.4
 Homepage: https://osmocom.org/projects/osmo-sip-conector/wiki
-Vcs-Git: git://git.osmocom.org/osmo-sip-connector.git
-Vcs-Browser: http://git.osmocom.org/osmo-sip-connector
+Vcs-Git: https://gitea.osmocom.org/cellular-infrastructure/osmo-sip-connector
+Vcs-Browser: https://gitea.osmocom.org/cellular-infrastructure/osmo-sip-connector
 
 Package: osmo-sip-connector
 Architecture: any

debian/postinst

@@ -0,0 +1,38 @@
+#!/bin/sh -e
+case "$1" in
+	configure)
+		# Create the osmocom group and user (if it doesn't exist yet)
+		if ! getent group osmocom >/dev/null; then
+			groupadd --system osmocom
+		fi
+		if ! getent passwd osmocom >/dev/null; then
+			useradd \
+				--system \
+				--gid osmocom \
+				--home-dir /var/lib/osmocom \
+				--shell /sbin/nologin \
+				--comment "Open Source Mobile Communications" \
+				osmocom
+		fi
+
+		# Fix permissions of previous (root-owned) install (OS#4107)
+		if dpkg --compare-versions "$2" le "1.7.0"; then
+			if [ -e /etc/osmocom/osmo-sip-connector.cfg ]; then
+				chown -v osmocom:osmocom /etc/osmocom/osmo-sip-connector.cfg
+				chmod -v 0660 /etc/osmocom/osmo-sip-connector.cfg
+			fi
+
+			if [ -d /etc/osmocom ]; then
+				chown -v root:osmocom /etc/osmocom
+				chmod -v 2775 /etc/osmocom
+			fi
+
+			mkdir -p /var/lib/osmocom
+			chown -R -v osmocom:osmocom /var/lib/osmocom
+		fi
+		;;
+esac
+
+# dh_installdeb(1) will replace this with shell code automatically
+# generated by other debhelper scripts.
+#DEBHELPER#

doc/examples/osmo-sip-connector.cfg

@@ -1,3 +1,11 @@
+log stderr
+ logging color 1
+ logging print category-hex 0
+ logging print category 1
+ logging timestamp 0
+ logging print file basename last
+ logging print level 1
+
 app
 mncc
  socket-path /tmp/msc_mncc

doc/manuals/chapters/overview.adoc

@@ -8,7 +8,7 @@ cover aspects of configuring and running OsmoSIPConnector.
 === About OsmoSIPConnector
 
 OsmoSIPConnector translates between Mobile Network Call Control (MNCC)
-used in the GSM newtwork and Voice over IP SIP call control messages so that
+used in the GSM network and Voice over IP SIP call control messages so that
 speech calls can traverse through the mobile network to SIP and vice versa. It
 has the following interfaces:
 
@@ -16,6 +16,27 @@ has the following interfaces:
 - SIP towards the PBX
 - The Osmocom typical telnet VTY interface.
 
+The SIP implemented by osmo-sip-connector can be characterized as follows:
+
+Only a SIP trunk is supported; it will appear to the remote SIP server (PBX) like
+another PBX (or a public network) interfaced via a trunk.  Specifically, this means
+there is no SIP REGISTER or any form of authentication supported.  You
+will need to configure the SIP peer to implicitly authorize the trunk by
+its IP address / port.
+
+osmo-sip-connector handles only the signaling translation between GSM CC
+and SIP, but does not handle RTP. The RTP user plane is passed
+transparently from the MSC-colocated osmo-mgw to the SIP side. This also
+means that no transcoding is performed. The RTP streams contain whatever
+cellular specific codec you have configured your network to use for this
+call (FR, EFR, HR, AMR).  Hence, **the SIP peer must support the
+codec[s] you have configured on your MSC/BSC**
+
+As the osmo-sip-connector attaches to the external MNCC socket of
+OsmoMSC, running osmo-sip-connector will disable the internal call
+routing of OsmoMSC, see the related OsmoMSC documentation.  All mobile
+originated calls originating in GSM will be passed to the SIP connector.
+
 Find the OsmoSIPConnector issue tracker and wiki online at
 
 - https://osmocom.org/projects/osmo-sip-connector

osmoappdesc.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # (C) 2016 by Holger Hans Peter Freyther
 

src/call.c

@@ -172,3 +172,20 @@ const char *call_leg_state(struct call_leg *leg)
 		return "Unknown call type";
 	}
 }
+
+void call_leg_rx_sdp(struct call_leg *leg, const char *rx_sdp)
+{
+	/* If no SDP was received, keep whatever SDP was previously seen. */
+	if (!rx_sdp || !*rx_sdp || !strncmp(leg->rx_sdp, rx_sdp, sizeof(leg->rx_sdp))) {
+		LOGP(DAPP, LOGL_DEBUG, "call(%u) leg(0x%p) no new SDP in %s\n", leg->call->id, leg,
+		     osmo_quote_str(rx_sdp, -1));
+		LOGP(DAPP, LOGL_DEBUG, "call(%u) leg(0x%p) keep stored SDP=%s\n", leg->call->id, leg,
+		     osmo_quote_str(leg->rx_sdp, -1));
+		return;
+	}
+	LOGP(DAPP, LOGL_DEBUG, "call(%u) leg(0x%p) received new SDP=%s\n", leg->call->id, leg, osmo_quote_str(rx_sdp, -1));
+	LOGP(DAPP, LOGL_DEBUG, "call(%u) leg(0x%p) replaced old SDP=%s\n", leg->call->id, leg,
+	     osmo_quote_str(leg->rx_sdp, -1));
+	OSMO_STRLCPY_ARRAY(leg->rx_sdp, rx_sdp);
+	leg->rx_sdp_changed = true;
+}

src/call.h

@@ -5,8 +5,10 @@
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/core/timer.h>
 #include <osmocom/core/utils.h>
+#include <osmocom/gsm/gsm29205.h>
 
 #include <stdbool.h>
+#include <netinet/in.h>
 
 struct sip_agent;
 struct mncc_connection;
@@ -30,6 +32,10 @@ struct call {
 
 	const char *source;
 	const char *dest;
+
+	/* Global Call Reference */
+	struct osmo_gcr_parsed gcr;
+	bool gcr_present;
 };
 
 enum {
@@ -49,11 +55,19 @@ struct call_leg {
 	/**
 	 * RTP data
 	 */
-	uint32_t	ip;
-	uint16_t	port;
+	struct sockaddr_storage addr;
 	uint32_t	payload_type;
 	uint32_t	payload_msg_type;
 
+	/* SDP as received for this call leg. If this is an MNCC call leg, contains the SDP most recently received in an
+	 * MNCC message; if this is a SIP call leg, contains the SDP most recently received in a SIP message. If no SDP
+	 * was received yet, this string is empty. Otherwise a nul terminated string. */
+	char rx_sdp[1024];
+	/* If the contents of rx_sdp[] changes, set rx_sdp_changed = true. When the other call leg transmits the next
+	 * message, it can decide whether to include SDP because there is new information, or whether to omit SDP
+	 * because it was already sent identically earlier. */
+	bool rx_sdp_changed;
+
 	/**
 	 * Remote started to ring/alert
 	 */
@@ -157,6 +171,8 @@ void calls_init(void);
 
 struct call_leg *call_leg_other(struct call_leg *leg);
 
+void call_leg_rx_sdp(struct call_leg *cl, const char *rx_sdp);
+
 void call_leg_release(struct call_leg *leg);
 
 

src/main.c

@@ -147,8 +147,7 @@ int main(int argc, char **argv)
 		exit(1);
 	}
 
-	rc = telnet_init_dynif(tall_mncc_ctx, NULL,
-				vty_get_bind_addr(), OSMO_VTY_PORT_MNCC_SIP);
+	rc = telnet_init_default(tall_mncc_ctx, NULL, OSMO_VTY_PORT_MNCC_SIP);
 	if (rc < 0)
 		exit(1);
 
@@ -158,9 +157,11 @@ int main(int argc, char **argv)
 	/* sofia sip */
 	sip_agent_init(&g_app.sip.agent, &g_app);
 	rc = sip_agent_start(&g_app.sip.agent);
-	if (rc < 0)
+	if (rc < 0) {
 		LOGP(DSIP, LOGL_ERROR,
-			"Failed to initialize SIP. Running broken\n");
+			"Failed to initialize SIP\n");
+		exit(1);
+	}
 
 	calls_init();
 	app_setup(&g_app);

src/mncc.c

@@ -130,43 +130,60 @@ static void mncc_fill_header(struct gsm_mncc *mncc, uint32_t msg_type, uint32_t
 	}
 }
 
-static void mncc_write(struct mncc_connection *conn, struct gsm_mncc *mncc, uint32_t callref)
+static int mncc_write(struct mncc_connection *conn, struct gsm_mncc *mncc)
 {
 	int rc;
 
+	LOGP(DMNCC, LOGL_DEBUG, "tx MNCC %s with SDP=%s\n", osmo_mncc_name(mncc->msg_type),
+	     osmo_quote_str(mncc->sdp, -1));
+
 	/*
 	 * TODO: we need to put cause in here for release or such? shall we return a
 	 * static struct?
 	 */
 	rc = write(conn->fd.fd, mncc, sizeof(*mncc));
-	LOGP(DMNCC, LOGL_DEBUG, "MNCC sent message type: %s\n", osmo_mncc_name(mncc->msg_type));
 	if (rc != sizeof(*mncc)) {
-		LOGP(DMNCC, LOGL_ERROR, "Failed to send message for call(%u)\n", callref);
+		LOGP(DMNCC, LOGL_ERROR, "Failed to send message for call(%u)\n", mncc->callref);
 		close_connection(conn);
 	}
+
+	return rc;
 }
 
-static void mncc_send(struct mncc_connection *conn, uint32_t msg_type, uint32_t callref)
+static int mncc_send(struct mncc_connection *conn, uint32_t msg_type, uint32_t callref)
 {
 	struct gsm_mncc mncc = { 0, };
 
 	mncc_fill_header(&mncc, msg_type, callref);
-	mncc_write(conn, &mncc, callref);
+	return mncc_write(conn, &mncc);
 }
 
-static void mncc_rtp_send(struct mncc_connection *conn, uint32_t msg_type, uint32_t callref)
+static int mncc_rtp_write(struct mncc_connection *conn, struct gsm_mncc_rtp *rtp)
 {
 	int rc;
+
+	LOGP(DMNCC, LOGL_DEBUG, "tx MNCC %s with SDP=%s\n", osmo_mncc_name(rtp->msg_type),
+	     osmo_quote_str(rtp->sdp, -1));
+
+	rc = write(conn->fd.fd, rtp, sizeof(*rtp));
+	if (rc != sizeof(*rtp)) {
+		LOGP(DMNCC, LOGL_ERROR, "Failed to send message for call(%u): %d\n", rtp->callref, rc);
+		close_connection(conn);
+	}
+
+	return rc;
+}
+
+static int mncc_rtp_send(struct mncc_connection *conn, uint32_t msg_type, uint32_t callref, const char *sdp)
+{
 	struct gsm_mncc_rtp mncc = { 0, };
 
 	mncc.msg_type = msg_type;
 	mncc.callref = callref;
+	if (sdp)
+		OSMO_STRLCPY_ARRAY(mncc.sdp, sdp);
 
-	rc = write(conn->fd.fd, &mncc, sizeof(mncc));
-	if (rc != sizeof(mncc)) {
-		LOGP(DMNCC, LOGL_ERROR, "Failed to send message for call(%u)\n", callref);
-		close_connection(conn);
-	}
+	return mncc_rtp_write(conn, &mncc);
 }
 
 /* Send a MNCC_RTP_CONNECT to the MSC for the given call legs */
@@ -174,7 +191,7 @@ static bool send_rtp_connect(struct mncc_call_leg *leg, struct call_leg *other)
 {
 	struct gsm_mncc_rtp mncc = { 0, };
 	int rc;
-	char ip_addr[INET_ADDRSTRLEN];
+	char ip_addr[INET6_ADDRSTRLEN];
 
 	/*
 	 * Send RTP CONNECT and we handle the general failure of it by
@@ -182,17 +199,20 @@ static bool send_rtp_connect(struct mncc_call_leg *leg, struct call_leg *other)
 	 */
 	mncc.msg_type = MNCC_RTP_CONNECT;
 	mncc.callref = leg->callref;
-	mncc.ip = ntohl(other->ip);
-	mncc.port = other->port;
+	mncc.addr = other->addr;
 	mncc.payload_type = other->payload_type;
+
+	/* Forward whichever SDP was last received on the other call leg */
+	OSMO_STRLCPY_ARRAY(mncc.sdp, other->rx_sdp);
+
 	/*
 	 * FIXME: mncc.payload_msg_type should already be compatible.. but
 	 * payload_type should be different..
 	 */
-	struct in_addr net = { .s_addr = other->ip };
-	inet_ntop(AF_INET, &net, ip_addr, sizeof(ip_addr));
-	LOGP(DMNCC, LOGL_DEBUG, "SEND rtp_connect: IP=(%s) PORT=(%u)\n", ip_addr, mncc.port);
-	rc = write(leg->conn->fd.fd, &mncc, sizeof(mncc));
+	LOGP(DMNCC, LOGL_DEBUG, "SEND rtp_connect: IP=(%s) PORT=(%u)\n",
+	     osmo_sockaddr_ntop((const struct sockaddr*)&other->addr, ip_addr),
+	     osmo_sockaddr_port((const struct sockaddr*)&other->addr));
+	rc = mncc_rtp_write(leg->conn, &mncc);
 	if (rc != sizeof(mncc)) {
 		LOGP(DMNCC, LOGL_ERROR, "Failed to send message for call(%u)\n",
 			leg->callref);
@@ -211,11 +231,21 @@ static void update_rtp(struct call_leg *_leg) {
 	if (_leg->type == CALL_TYPE_MNCC) {
 		leg = (struct mncc_call_leg *) _leg;
 		struct call_leg *other = call_leg_other(&leg->base);
+		if (!other)
+			goto ret_release;
 		send_rtp_connect(leg, other);
-	} else {
+	} else if (_leg->type == CALL_TYPE_SIP) {
 		leg = (struct mncc_call_leg *) call_leg_other(_leg);
+		if (!leg)
+			goto ret_release;
 		send_rtp_connect(leg, _leg);
+	} else {
+		OSMO_ASSERT(false);
 	}
+	return;
+ret_release:
+	LOGP(DMNCC, LOGL_ERROR, "Failed to find other leg.\n");
+	_leg->release_call(_leg);
 }
 
 
@@ -255,14 +285,15 @@ static void mncc_call_leg_ring(struct call_leg *_leg)
 	out_mncc.progress.location = GSM48_CAUSE_LOC_PRN_S_LU; /* Private network serving the local user */
 	out_mncc.progress.descr = GSM48_PROGR_IN_BAND_AVAIL; /* In-band information or appropriate pattern now available */
 
-	mncc_write(leg->conn, &out_mncc, leg->callref);
+	mncc_write(leg->conn, &out_mncc);
 
 	/*
 	 * If we have remote IP/port let's connect it already.
 	 * FIXME: We would like to keep this as recvonly...
 	 */
 	other_leg = call_leg_other(&leg->base);
-	if (other_leg && other_leg->port != 0 && other_leg->ip != 0)
+	if (other_leg && other_leg->addr.ss_family != AF_UNSPEC &&
+	    osmo_sockaddr_port((const struct sockaddr *)&other_leg->addr) != 0)
 		send_rtp_connect(leg, other_leg);
 }
 
@@ -314,8 +345,12 @@ static void mncc_call_leg_release(struct call_leg *_leg)
 /* Close the MNCC connection/socket */
 static void close_connection(struct mncc_connection *conn)
 {
+	if (conn->fd.fd < 0)
+		return;
+
 	osmo_fd_unregister(&conn->fd);
 	close(conn->fd.fd);
+	conn->fd.fd = -1;
 	osmo_timer_schedule(&conn->reconnect, 5, 0);
 	conn->state = MNCC_DISCONNECTED;
 	if (conn->on_disconnect)
@@ -379,11 +414,16 @@ static void check_rtp_connect(struct mncc_connection *conn, const char *buf, int
 	leg = mncc_find_leg_not_released(rtp->callref);
 	if (!leg) {
 		LOGP(DMNCC, LOGL_ERROR, "leg(%u) can not be found\n", rtp->callref);
-		return mncc_send(conn, MNCC_REJ_REQ, rtp->callref);
+		mncc_send(conn, MNCC_REJ_REQ, rtp->callref);
+		return;
 	}
 
+	call_leg_rx_sdp(&leg->base, rtp->sdp);
+
 	/* extract information about where the RTP is */
-	if (rtp->ip != 0 || rtp->port != 0 || rtp->payload_type != 0)
+	if (rtp->addr.ss_family != AF_UNSPEC ||
+	    osmo_sockaddr_port((const struct sockaddr *)&rtp->addr) != 0 ||
+	    rtp->payload_type != 0)
 		return;
 
 	LOGP(DMNCC, LOGL_ERROR, "leg(%u) rtp connect failed\n", rtp->callref);
@@ -398,7 +438,7 @@ static void check_rtp_create(struct mncc_connection *conn, const char *buf, int
 {
 	const struct gsm_mncc_rtp *rtp;
 	struct mncc_call_leg *leg;
-	char ip_addr[INET_ADDRSTRLEN];
+	char ip_addr[INET6_ADDRSTRLEN];
 
 	if (rc < sizeof(*rtp)) {
 		LOGP(DMNCC, LOGL_ERROR, "gsm_mncc_rtp of wrong size %d < %zu\n",
@@ -410,21 +450,22 @@ static void check_rtp_create(struct mncc_connection *conn, const char *buf, int
 	leg = mncc_find_leg_not_released(rtp->callref);
 	if (!leg) {
 		LOGP(DMNCC, LOGL_ERROR, "call(%u) can not be found\n", rtp->callref);
-		return mncc_send(conn, MNCC_REJ_REQ, rtp->callref);
+		mncc_send(conn, MNCC_REJ_REQ, rtp->callref);
+		return;
 	}
 
 	/* extract information about where the RTP is */
-	leg->base.ip = htonl(rtp->ip);
-	leg->base.port = rtp->port;
+	leg->base.addr = rtp->addr;
 	leg->base.payload_type = rtp->payload_type;
 	leg->base.payload_msg_type = rtp->payload_msg_type;
+	call_leg_rx_sdp(&leg->base, rtp->sdp);
 
 	/* TODO.. now we can continue with the call */
-	struct in_addr net = { .s_addr = leg->base.ip };
-	inet_ntop(AF_INET, &net, ip_addr, sizeof(ip_addr));
 	LOGP(DMNCC, LOGL_INFO,
 		"RTP continue leg(%u) ip(%s), port(%u) pt(%u) ptm(%u)\n",
-		leg->callref, ip_addr, leg->base.port,
+		leg->callref,
+		osmo_sockaddr_ntop((const struct sockaddr*)&leg->base.addr, ip_addr),
+		osmo_sockaddr_port((const struct sockaddr*)&leg->base.addr),
 		leg->base.payload_type, leg->base.payload_msg_type);
 	stop_cmd_timer(leg, MNCC_RTP_CREATE);
 	continue_call(leg);
@@ -457,8 +498,11 @@ static void check_setup(struct mncc_connection *conn, const char *buf, int rc)
 	const struct gsm_mncc_number *called;
 	struct call *call;
 	struct mncc_call_leg *leg;
+	struct call_leg *other_leg;
+	const char *sdp = NULL;
+	struct osmo_gcr_parsed gcr;
 
-	if (rc != sizeof(*data)) {
+	if (rc < sizeof(*data)) {
 		LOGP(DMNCC, LOGL_ERROR, "gsm_mncc of wrong size %d vs. %zu\n",
 			rc, sizeof(*data));
 		return close_connection(conn);
@@ -473,7 +517,8 @@ static void check_setup(struct mncc_connection *conn, const char *buf, int rc)
 			LOGP(DMNCC, LOGL_ERROR,
 				"MNCC leg(%u) without called addr fields(%u)\n",
 				data->callref, data->fields);
-			return mncc_send(conn, MNCC_REJ_REQ, data->callref);
+			mncc_send(conn, MNCC_REJ_REQ, data->callref);
+			return;
 		}
 
 		/* Emergency without a called number present. Use the standard "emergency" number. */
@@ -484,14 +529,26 @@ static void check_setup(struct mncc_connection *conn, const char *buf, int rc)
 		LOGP(DMNCC, LOGL_ERROR,
 			"MNCC leg(%u) without calling addr fields(%u)\n",
 			data->callref, data->fields);
-		return mncc_send(conn, MNCC_REJ_REQ, data->callref);
+		mncc_send(conn, MNCC_REJ_REQ, data->callref);
+		return;
 	}
 
 	/* TODO.. bearer caps and better audio handling */
 	if (!continue_setup(conn, data)) {
 		LOGP(DMNCC, LOGL_ERROR,
 			"MNCC screening parameters failed leg(%u)\n", data->callref);
-		return mncc_send(conn, MNCC_REJ_REQ, data->callref);
+		mncc_send(conn, MNCC_REJ_REQ, data->callref);
+		return;
+	}
+
+	/* Decode the Global Call Reference (if present) */
+	if (data->fields & MNCC_F_GCR) {
+		if (osmo_dec_gcr(&gcr, data->gcr, sizeof(data->gcr)) < 0) {
+			LOGP(DMNCC, LOGL_ERROR,
+				"MNCC leg(%u) failed to parse GCR\n", data->callref);
+			mncc_send(conn, MNCC_REJ_REQ, data->callref);
+			return;
+		}
 	}
 
 	/* Create an RTP port and then allocate a call */
@@ -499,7 +556,8 @@ static void check_setup(struct mncc_connection *conn, const char *buf, int rc)
 	if (!call) {
 		LOGP(DMNCC, LOGL_ERROR,
 			"MNCC leg(%u) failed to allocate call\n", data->callref);
-		return mncc_send(conn, MNCC_REJ_REQ, data->callref);
+		mncc_send(conn, MNCC_REJ_REQ, data->callref);
+		return;
 	}
 
 	leg = (struct mncc_call_leg *) call->initial;
@@ -514,13 +572,25 @@ static void check_setup(struct mncc_connection *conn, const char *buf, int rc)
 	memcpy(&leg->called, called, sizeof(leg->called));
 	memcpy(&leg->calling, &data->calling, sizeof(leg->calling));
 	memcpy(&leg->imsi, data->imsi, sizeof(leg->imsi));
+	call_leg_rx_sdp(&leg->base, data->sdp);
+
+	if (data->fields & MNCC_F_GCR) {
+		leg->base.call->gcr_present = true;
+		leg->base.call->gcr = gcr;
+	}
 
 	LOGP(DMNCC, LOGL_INFO,
 		"Created call(%u) with MNCC leg(%u) IMSI(%.16s)\n",
 		call->id, leg->callref, data->imsi);
 
+	other_leg = call_leg_other(&leg->base);
+	if (other_leg && *other_leg->rx_sdp && other_leg->rx_sdp_changed) {
+		sdp = other_leg->rx_sdp;
+		other_leg->rx_sdp_changed = false;
+	}
+
 	start_cmd_timer(leg, MNCC_RTP_CREATE);
-	mncc_rtp_send(conn, MNCC_RTP_CREATE, data->callref);
+	mncc_rtp_send(conn, MNCC_RTP_CREATE, data->callref, sdp);
 }
 
 /*! Find MNCC Call leg by given MNCC message
@@ -534,7 +604,7 @@ static struct mncc_call_leg *find_leg(struct mncc_connection *conn,
 {
 	struct mncc_call_leg *leg;
 
-	if (rc != sizeof(**mncc)) {
+	if (rc < sizeof(**mncc)) {
 		LOGP(DMNCC, LOGL_ERROR, "gsm_mncc of wrong size %d vs. %zu\n",
 			rc, sizeof(**mncc));
 		close_connection(conn);
@@ -624,6 +694,8 @@ static void check_stp_cmpl_ind(struct mncc_connection *conn, const char *buf, in
 	if (!leg)
 		return;
 
+	call_leg_rx_sdp(&leg->base, data->sdp);
+
 	LOGP(DMNCC, LOGL_INFO, "leg(%u) is now connected.\n", leg->callref);
 	stop_cmd_timer(leg, MNCC_SETUP_COMPL_IND);
 	leg->state = MNCC_CC_CONNECTED;
@@ -653,17 +725,28 @@ static void check_cnf_ind(struct mncc_connection *conn, const char *buf, int rc)
 {
 	const struct gsm_mncc *data;
 	struct mncc_call_leg *leg;
+	struct call_leg *other_leg;
+	const char *sdp = NULL;
 
 	leg = find_leg(conn, buf, rc, &data);
 	if (!leg)
 		return;
 
+	call_leg_rx_sdp(&leg->base, data->sdp);
+
+	/* Forward SDP received from the other side */
+	other_leg = call_leg_other(&leg->base);
+	if (other_leg && *other_leg->rx_sdp && other_leg->rx_sdp_changed) {
+		sdp = other_leg->rx_sdp;
+		other_leg->rx_sdp_changed = false;
+	}
+
 	LOGP(DMNCC, LOGL_DEBUG,
 		"leg(%u) confirmed. creating RTP socket.\n",
 		leg->callref);
 
 	start_cmd_timer(leg, MNCC_RTP_CREATE);
-	mncc_rtp_send(conn, MNCC_RTP_CREATE, data->callref);
+	mncc_rtp_send(conn, MNCC_RTP_CREATE, data->callref, sdp);
 }
 
 static void check_alrt_ind(struct mncc_connection *conn, const char *buf, int rc)
@@ -676,6 +759,8 @@ static void check_alrt_ind(struct mncc_connection *conn, const char *buf, int rc
 	if (!leg)
 		return;
 
+	call_leg_rx_sdp(&leg->base, data->sdp);
+
 	LOGP(DMNCC, LOGL_DEBUG,
 		"leg(%u) is alerting.\n", leg->callref);
 
@@ -754,6 +839,8 @@ static void check_stp_cnf(struct mncc_connection *conn, const char *buf, int rc)
 	if (!leg)
 		return;
 
+	call_leg_rx_sdp(&leg->base, data->sdp);
+
 	LOGP(DMNCC, LOGL_DEBUG, "leg(%u) setup completed\n", leg->callref);
 
 	other_leg = call_leg_other(&leg->base);
@@ -783,6 +870,8 @@ static void check_dtmf_start(struct mncc_connection *conn, const char *buf, int
 	if (!leg)
 		return;
 
+	call_leg_rx_sdp(&leg->base, data->sdp);
+
 	LOGP(DMNCC, LOGL_DEBUG, "leg(%u) DTMF key=%c\n", leg->callref, data->keypad);
 
 	other_leg = call_leg_other(&leg->base);
@@ -792,7 +881,7 @@ static void check_dtmf_start(struct mncc_connection *conn, const char *buf, int
 	mncc_fill_header(&out_mncc, MNCC_START_DTMF_RSP, leg->callref);
 	out_mncc.fields |= MNCC_F_KEYPAD;
 	out_mncc.keypad = data->keypad;
-	mncc_write(conn, &out_mncc, leg->callref);
+	mncc_write(conn, &out_mncc);
 }
 
 static void check_dtmf_stop(struct mncc_connection *conn, const char *buf, int rc)
@@ -805,12 +894,14 @@ static void check_dtmf_stop(struct mncc_connection *conn, const char *buf, int r
 	if (!leg)
 		return;
 
+	call_leg_rx_sdp(&leg->base, data->sdp);
+
 	LOGP(DMNCC, LOGL_DEBUG, "leg(%u) DTMF key=%c\n", leg->callref, data->keypad);
 
 	mncc_fill_header(&out_mncc, MNCC_STOP_DTMF_RSP, leg->callref);
 	out_mncc.fields |= MNCC_F_KEYPAD;
 	out_mncc.keypad = data->keypad;
-	mncc_write(conn, &out_mncc, leg->callref);
+	mncc_write(conn, &out_mncc);
 }
 
 static void check_hello(struct mncc_connection *conn, const char *buf, int rc)
@@ -839,6 +930,7 @@ int mncc_create_remote_leg(struct mncc_connection *conn, struct call *call)
 {
 	struct mncc_call_leg *leg;
 	struct gsm_mncc mncc = { 0, };
+	struct msgb *msg;
 	int rc;
 
 	leg = talloc_zero(call, struct mncc_call_leg);
@@ -884,17 +976,34 @@ int mncc_create_remote_leg(struct mncc_connection *conn, struct call *call)
 		OSMO_STRLCPY_ARRAY(mncc.called.number, call->dest);
 	}
 
+	/* Encode the Global Call Reference (if present) */
+	if (call->gcr_present) {
+		msg = msgb_alloc(sizeof(mncc.gcr), "MNCC GCR");
+		if (msg == NULL || (rc = osmo_enc_gcr(msg, &call->gcr)) == 0) {
+			LOGP(DMNCC, LOGL_ERROR, "MNCC leg(%u) failed to encode GCR\n", call->id);
+		} else {
+			memcpy(&mncc.gcr[0], msg->data, rc);
+			mncc.fields |= MNCC_F_GCR;
+		}
+		msgb_free(msg);
+	}
+
+	/* The call->initial leg is a SIP call leg that starts an MT call. There was SDP received in the SIP INVITE that
+	 * started this call. This here will be the call->remote, always forwarding the SDP that came in on
+	 * call->initial. */
+	if (call->initial && call->initial->rx_sdp_changed) {
+		OSMO_STRLCPY_ARRAY(mncc.sdp, call->initial->rx_sdp);
+		call->initial->rx_sdp_changed = false;
+	}
+
 	/*
 	 * TODO/FIXME:
-	 *  - Determine/request channel based on offered audio codecs
 	 *  - Screening, redirect?
-	 *  - Synth. the bearer caps based on codecs?
 	 */
-	rc = write(conn->fd.fd, &mncc, sizeof(mncc));
+	rc = mncc_write(conn, &mncc);
 	if (rc != sizeof(mncc)) {
 		LOGP(DMNCC, LOGL_ERROR, "Failed to send message leg(%u)\n",
 			leg->callref);
-		close_connection(conn);
 		talloc_free(leg);
 		return -1;
 	}
@@ -914,6 +1023,7 @@ static void mncc_reconnect(void *data)
 		LOGP(DMNCC, LOGL_ERROR, "Failed to connect(%s). Retrying\n",
 			conn->app->mncc.path);
 		conn->state = MNCC_DISCONNECTED;
+		conn->fd.fd = -1;
 		osmo_timer_schedule(&conn->reconnect, 5, 0);
 		return;
 	}
@@ -922,6 +1032,53 @@ static void mncc_reconnect(void *data)
 	conn->state = MNCC_WAIT_VERSION;
 }
 
+static inline void log_mncc(const char *label, const uint8_t *buf, size_t buflen)
+{
+	uint32_t msg_type;
+	const struct gsm_mncc *gsm_mncc;
+	const struct gsm_mncc_rtp *gsm_mncc_rtp;
+	const char *sdp = NULL;
+
+	/* Any size errors will be logged elsewhere already, so just exit here if the buffer is too small. */
+	if (buflen < 4)
+		return;
+	memcpy(&msg_type, buf, 4);
+
+	switch (msg_type) {
+	case MNCC_SETUP_IND:
+	case MNCC_DISC_IND:
+	case MNCC_REL_IND:
+	case MNCC_REJ_IND:
+	case MNCC_REL_CNF:
+	case MNCC_SETUP_COMPL_IND:
+	case MNCC_SETUP_CNF:
+	case MNCC_CALL_CONF_IND:
+	case MNCC_ALERT_IND:
+	case MNCC_HOLD_IND:
+	case MNCC_RETRIEVE_IND:
+		if (buflen < sizeof(gsm_mncc))
+			return;
+		gsm_mncc = (void *)buf;
+		sdp = gsm_mncc->sdp;
+		break;
+	case MNCC_RTP_CREATE:
+	case MNCC_RTP_CONNECT:
+		if (buflen < sizeof(gsm_mncc_rtp))
+			return;
+		gsm_mncc_rtp = (void *)buf;
+		sdp = gsm_mncc_rtp->sdp;
+		break;
+
+	default:
+		break;
+	}
+	if (sdp)
+		LOGP(DMNCC, LOGL_DEBUG, "%sMNCC %s with SDP=%s\n", label, osmo_mncc_name(msg_type),
+		     osmo_quote_str(sdp, -1));
+	else
+		LOGP(DMNCC, LOGL_DEBUG, "%sMNCC %s\n", label, osmo_mncc_name(msg_type));
+}
+
 /* osmo-fd read call-back for MNCC socket: read MNCC message + dispatch it */
 static int mncc_data(struct osmo_fd *fd, unsigned int what)
 {
@@ -941,10 +1098,10 @@ static int mncc_data(struct osmo_fd *fd, unsigned int what)
 		goto bad_data;
 	}
 
+	log_mncc("rx ", (void *)buf, rc);
+
+	/* Handle the received MNCC message */
 	memcpy(&msg_type, buf, 4);
-
-	LOGP(DMNCC, LOGL_DEBUG, "MNCC rcvd message type: %s\n", osmo_mncc_name(msg_type));
-
 	switch (msg_type) {
 	case MNCC_SOCKET_HELLO:
 		check_hello(conn, buf, rc);
@@ -1012,6 +1169,7 @@ void mncc_connection_init(struct mncc_connection *conn, struct app_config *cfg)
 	conn->reconnect.data = conn;
 	conn->fd.cb = mncc_data;
 	conn->fd.data = conn;
+	conn->fd.fd = -1;
 	conn->app = cfg;
 	conn->state = MNCC_DISCONNECTED;
 }

src/mncc_protocol.h

@@ -1,4 +1,4 @@
-/* GSM Mobile Radio Interface Layer 3 messages on the A-bis interface 
+/* GSM Mobile Radio Interface Layer 3 messages on the A-bis interface
  * 3GPP TS 04.08 version 7.21.0 Release 1998 / ETSI TS 100 940 V7.21.0 */
 
 /* (C) 2008-2009 by Harald Welte <laforge@gnumonks.org>
@@ -28,6 +28,7 @@
 #include <osmocom/gsm/mncc.h>
 
 #include <stdint.h>
+#include <netinet/in.h>
 
 struct gsm_network;
 struct msgb;
@@ -122,6 +123,7 @@ struct gsm_call {
 #define MNCC_F_CCCAP		0x0800
 #define MNCC_F_KEYPAD		0x1000
 #define MNCC_F_SIGNAL		0x2000
+#define MNCC_F_GCR		0x4000
 
 struct gsm_mncc {
 	/* context based information */
@@ -158,6 +160,12 @@ struct gsm_mncc {
 
 	unsigned char	lchan_type;
 	unsigned char	lchan_mode;
+
+	/* Global Call Reference (encoded as per 3GPP TS 29.205) */
+	uint8_t		gcr[16];
+
+	/* A buffer to contain SDP ('\0' terminated) */
+	char		sdp[1024];
 };
 
 struct gsm_data_frame {
@@ -166,7 +174,7 @@ struct gsm_data_frame {
 	unsigned char	data[0];
 };
 
-#define MNCC_SOCK_VERSION	5
+#define MNCC_SOCK_VERSION	8
 struct gsm_mncc_hello {
 	uint32_t	msg_type;
 	uint32_t	version;
@@ -185,10 +193,10 @@ struct gsm_mncc_hello {
 struct gsm_mncc_rtp {
 	uint32_t	msg_type;
 	uint32_t	callref;
-	uint32_t	ip;
-	uint16_t	port;
+	struct sockaddr_storage addr;
 	uint32_t	payload_type;
 	uint32_t	payload_msg_type;
+	char		sdp[1024];
 };
 
 struct gsm_mncc_bridge {

src/sdp.c

@@ -32,6 +32,8 @@
 
 #include <string.h>
 
+#include <osmocom/core/socket.h>
+
 /*
  * Check if the media mode attribute exists in SDP, in this
  * case update the passed pointer with the media mode
@@ -63,11 +65,11 @@ bool sdp_get_sdp_mode(const sip_t *sip, sdp_mode_t *mode) {
 
 	if (!sdp->sdp_media || !sdp->sdp_media->m_mode) {
 		sdp_parser_free(parser);
-		return sdp_sendrecv;
+		return false;
 	}
 
-	sdp_parser_free(parser);
 	*mode = sdp->sdp_media->m_mode;
+	sdp_parser_free(parser);
 	return true;
 }
 
@@ -122,6 +124,7 @@ bool sdp_screen_sdp(const sip_t *sip)
 	}
 
 	sdp_parser_free(parser);
+	/* FIXME: osmo-sip-connector should not interfere in codecs at all */
 	return false;
 
 success:
@@ -129,6 +132,9 @@ success:
 	return true;
 }
 
+/* Extract RTP address, port and payload type from SDP received in SIP message, in order to populate the legacy MNCC
+ * fields, for backwards compatibility. osmo-sip-connector now always sends the entire SDP info unchanged via MNCC,
+ * which obsoletes the legacy fields. But for backwards compatibility, still populate the legacy fields. */
 bool sdp_extract_sdp(struct sip_call_leg *leg, const sip_t *sip, bool any_codec)
 {
 	sdp_connection_t *conn;
@@ -136,6 +142,7 @@ bool sdp_extract_sdp(struct sip_call_leg *leg, const sip_t *sip, bool any_codec)
 	sdp_parser_t *parser;
 	sdp_media_t *media;
 	const char *sdp_data;
+	uint16_t port;
 	bool found_conn = false, found_map = false;
 
 	if (!sip->sip_payload || !sip->sip_payload->pl_data) {
@@ -159,12 +166,22 @@ bool sdp_extract_sdp(struct sip_call_leg *leg, const sip_t *sip, bool any_codec)
 	}
 
 	for (conn = sdp->sdp_connection; conn; conn = conn->c_next) {
-		struct in_addr addr;
-
-		if (conn->c_addrtype != sdp_addr_ip4)
+		switch (conn->c_addrtype) {
+		case sdp_addr_ip4:
+			if (inet_pton(AF_INET, conn->c_address,
+				      &((struct sockaddr_in*)&leg->base.addr)->sin_addr) != 1)
+				continue;
+			leg->base.addr.ss_family = AF_INET;
+			break;
+		case sdp_addr_ip6:
+			if (inet_pton(AF_INET6, conn->c_address,
+				      &((struct sockaddr_in6*)&leg->base.addr)->sin6_addr) != 1)
+				continue;
+			leg->base.addr.ss_family = AF_INET6;
+			break;
+		default:
 			continue;
-		inet_aton(conn->c_address, &addr);
-		leg->base.ip = addr.s_addr;
+		}
 		found_conn = true;
 		break;
 	}
@@ -178,10 +195,12 @@ bool sdp_extract_sdp(struct sip_call_leg *leg, const sip_t *sip, bool any_codec)
 			continue;
 
 		for (map = media->m_rtpmaps; map; map = map->rm_next) {
-			if (!any_codec && strcasecmp(map->rm_encoding, leg->wanted_codec) != 0)
+			if (!any_codec
+			    && leg->wanted_codec
+			    && strcasecmp(map->rm_encoding, leg->wanted_codec) != 0)
 				continue;
 
-			leg->base.port = media->m_port;
+			port = media->m_port;
 			leg->base.payload_type = map->rm_pt;
 			found_map = true;
 			break;
@@ -195,27 +214,62 @@ bool sdp_extract_sdp(struct sip_call_leg *leg, const sip_t *sip, bool any_codec)
 		LOGP(DSIP, LOGL_ERROR, "leg(%p) did not find %d/%d\n",
 			leg, found_conn, found_map);
 		sdp_parser_free(parser);
+		/* FIXME: osmo-sip-connector should not interfere in codecs at all */
 		return false;
 	}
 
+	switch (leg->base.addr.ss_family) {
+	case AF_INET:
+		((struct sockaddr_in*)&leg->base.addr)->sin_port = htons(port);
+		break;
+	case AF_INET6:
+		((struct sockaddr_in6*)&leg->base.addr)->sin6_port = htons(port);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+
 	sdp_parser_free(parser);
 	return true;
 }
 
+/* One leg has sent a SIP or MNCC message, which is now translated/forwarded to the counterpart MNCC or SIP.
+ * Take as much from the source's SDP as possible, but make sure the connection mode reflects the 'mode' arg (sendrecv,
+ * recvonly, sendonly, inactive).
+ * For example, if the MSC sent an MNCC_SETUP_IND, the SDP from the MNCC is found in 'other', while 'leg' reflects the
+ * SIP side that should receive this SDP in the SIP Invite that is being composed by the caller of this function.
+ * \param leg  The target for which the returned SDP is intended.
+ * \param other  The source of which we are to reflect the SDP.
+ * \return  SDP string, using 'leg' as talloc ctx.
+ */
 char *sdp_create_file(struct sip_call_leg *leg, struct call_leg *other, sdp_mode_t mode)
 {
-	struct in_addr net = { .s_addr = other->ip };
-	char *fmtp_str = NULL, *sdp;
-	char *mode_attribute;
-	char ip_addr[INET_ADDRSTRLEN];
+	sdp_parser_t *parser;
+	sdp_session_t *sdp;
+	sdp_media_t *media;
+	const char *sdp_data;
+	sdp_printer_t *printer;
+	char buf[1024];
+	const char *sdp_str;
+	char *ret;
 
-	inet_ntop(AF_INET, &net, ip_addr, sizeof(ip_addr));
-	leg->wanted_codec = app_media_name(other->payload_msg_type);
+	sdp_data = other->rx_sdp;
 
-	if (strcmp(leg->wanted_codec, "AMR") == 0)
-		fmtp_str = talloc_asprintf(leg, "a=fmtp:%d octet-align=1\r\n", other->payload_type);
+	if (!*sdp_data) {
+		/* Legacy compat: We have not received any SDP from the other call leg. Compose some original SDP from
+		 * the RTP information we have. */
+		char *fmtp_str = NULL;
+		char *mode_attribute;
+		char ip_addr[INET6_ADDRSTRLEN];
+		char ipv;
 
-	switch (mode) {
+		osmo_sockaddr_ntop((const struct sockaddr *)&other->addr, ip_addr);
+		ipv = other->addr.ss_family == AF_INET6 ? '6' : '4';
+		leg->wanted_codec = app_media_name(other->payload_msg_type);
+		if (strcmp(leg->wanted_codec, "AMR") == 0)
+			fmtp_str = talloc_asprintf(leg, "a=fmtp:%d octet-align=1\r\n", other->payload_type);
+
+		switch (mode) {
 		case sdp_inactive:
 			mode_attribute = "a=inactive\r\n";
 			break;
@@ -231,24 +285,67 @@ char *sdp_create_file(struct sip_call_leg *leg, struct call_leg *other, sdp_mode
 		default:
 			OSMO_ASSERT(false);
 			break;
+		}
+
+		return talloc_asprintf(leg,
+				       "v=0\r\n"
+				       "o=Osmocom 0 0 IN IP%c %s\r\n"
+				       "s=GSM Call\r\n"
+				       "c=IN IP%c %s\r\n"
+				       "t=0 0\r\n"
+				       "m=audio %d RTP/AVP %d\r\n"
+				       "%s"
+				       "a=rtpmap:%d %s/8000\r\n"
+				       "%s",
+				       ipv, ip_addr, ipv, ip_addr,
+				       osmo_sockaddr_port((const struct sockaddr *)&other->addr),
+				       other->payload_type,
+				       fmtp_str ? fmtp_str : "",
+				       other->payload_type,
+				       leg->wanted_codec,
+				       mode_attribute);
 	}
 
-	sdp = talloc_asprintf(leg,
-				"v=0\r\n"
-				"o=Osmocom 0 0 IN IP4 %s\r\n"
-				"s=GSM Call\r\n"
-				"c=IN IP4 %s\r\n"
-				"t=0 0\r\n"
-				"m=audio %d RTP/AVP %d\r\n"
-				"%s"
-				"a=rtpmap:%d %s/8000\r\n"
-				"%s",
-				ip_addr, ip_addr,
-				other->port, other->payload_type,
-				fmtp_str ? fmtp_str : "",
-				other->payload_type,
-				leg->wanted_codec,
-				mode_attribute);
-	talloc_free(fmtp_str);
-	return sdp;
+	/* We have received SDP from the other call leg. Forward this as-is, only apply the mode the caller requests:
+	 * parse SDP, set media mode, recompose. */
+	/* TODO: currently, we often detect the media mode from parsing SDP, and then forward the same SDP, applying the
+	 * same mode to it below. It may make sense to completely skip parsing and composition: the mode is usually
+	 * already in the received SDP.
+	 * However, there are some invocations of this function (sdp_create_file()) with hardcoded modes. Take a look if
+	 * that is really necessary, and if not, just drop below parsing + recomposition and use the sdp_data as is.
+	 */
+	parser = sdp_parse(NULL, sdp_data, strlen(sdp_data), 0);
+	if (!parser) {
+		LOGP(DSIP, LOGL_ERROR, "leg(%p) failed to parse SDP\n", other);
+		return talloc_strdup(leg, sdp_data);
+	}
+
+	sdp = sdp_session(parser);
+	if (!sdp) {
+		LOGP(DSIP, LOGL_INFO, "leg(%p) no SDP session in %s, returning SDP unchanged\n", other, osmo_quote_str(sdp_data, -1));
+		sdp_parser_free(parser);
+		return talloc_strdup(leg, sdp_data);
+	}
+
+	for (media = sdp->sdp_media; media; media = media->m_next)
+		media->m_mode = mode;
+
+	printer = sdp_print(NULL, sdp, buf, sizeof(buf), sdp_f_mode_always);
+	if (!printer) {
+		LOGP(DSIP, LOGL_ERROR, "leg(%p) failed to print SDP\n", other);
+		sdp_parser_free(parser);
+		return talloc_strdup(leg, sdp_data);
+	}
+
+	sdp_str = sdp_message(printer);
+	if (!sdp_str) {
+		LOGP(DSIP, LOGL_ERROR, "leg(%p) failed to print SDP: %s\n", other, sdp_printing_error(printer));
+		sdp_str = sdp_data;
+	}
+
+	ret = talloc_strdup(leg, sdp_str);
+
+	sdp_parser_free(parser);
+	sdp_printer_free(printer);
+	return ret;
 }

src/sdp.h

@@ -11,5 +11,4 @@ struct call_leg;
 bool sdp_get_sdp_mode(const sip_t *sip, sdp_mode_t *mode);
 bool sdp_screen_sdp(const sip_t *sip);
 bool sdp_extract_sdp(struct sip_call_leg *leg, const sip_t *sip, bool any_codec);
-
-char *sdp_create_file(struct sip_call_leg *, struct call_leg *, sdp_mode_t mode);
+char *sdp_create_file(struct sip_call_leg *leg, struct call_leg *other, sdp_mode_t mode);

src/sip.c

@@ -25,6 +25,8 @@
 #include "sdp.h"
 
 #include <osmocom/core/utils.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/gsm/tlv.h>
 
 #include <sofia-sip/sip_status.h>
 #include <sofia-sip/su_log.h>
@@ -33,6 +35,7 @@
 #include <talloc.h>
 
 #include <string.h>
+#include <netinet/in.h>
 
 extern void *tall_mncc_ctx;
 
@@ -43,6 +46,12 @@ static void sip_dtmf_call(struct call_leg *_leg, int keypad);
 static void sip_hold_call(struct call_leg *_leg);
 static void sip_retrieve_call(struct call_leg *_leg);
 
+static const char *sip_get_sdp(const sip_t *sip)
+{
+	if (!sip || !sip->sip_payload)
+		return NULL;
+	return sip->sip_payload->pl_data;
+}
 
 /* Find a SIP Call leg by given nua_handle */
 static struct sip_call_leg *sip_find_leg(nua_handle_t *nh)
@@ -110,10 +119,22 @@ static void new_call(struct sip_agent *agent, nua_handle_t *nh,
 	struct call *call;
 	struct sip_call_leg *leg;
 	const char *from = NULL, *to = NULL;
-	char ip_addr[INET_ADDRSTRLEN];
+	char ip_addr[INET6_ADDRSTRLEN];
+	bool xgcr_hdr_present = false;
+	uint8_t xgcr_hdr[28] = { 0 };
 
 	LOGP(DSIP, LOGL_INFO, "Incoming call(%s) handle(%p)\n", sip->sip_call_id->i_id, nh);
 
+	sip_unknown_t *unknown_header = sip->sip_unknown;
+	while (unknown_header != NULL) {
+		if (!strcmp("X-Global-Call-Ref", unknown_header->un_name)) {
+			osmo_hexparse(unknown_header->un_value, xgcr_hdr, sizeof(xgcr_hdr));
+			xgcr_hdr_present = true;
+			break;
+		}
+		unknown_header = unknown_header->un_next;
+	}
+
 	if (!sdp_screen_sdp(sip)) {
 		LOGP(DSIP, LOGL_ERROR, "No supported codec.\n");
 		nua_respond(nh, SIP_406_NOT_ACCEPTABLE, TAG_END());
@@ -122,11 +143,17 @@ static void new_call(struct sip_agent *agent, nua_handle_t *nh,
 	}
 
 	call = call_sip_create();
-	if (!call) {
-		LOGP(DSIP, LOGL_ERROR, "No supported codec.\n");
-		nua_respond(nh, SIP_500_INTERNAL_SERVER_ERROR, TAG_END());
-		nua_handle_destroy(nh);
-		return;
+	OSMO_ASSERT(call);
+
+	/* Decode Decode the Global Call Reference (if present) */
+	if (xgcr_hdr_present) {
+		if (osmo_dec_gcr(&call->gcr, xgcr_hdr, sizeof(xgcr_hdr)) < 0) {
+			LOGP(DSIP, LOGL_ERROR, "Failed to parse X-Global-Call-Ref.\n");
+			nua_respond(nh, SIP_406_NOT_ACCEPTABLE, TAG_END());
+			nua_handle_destroy(nh);
+			return;
+		}
+		call->gcr_present = true;
 	}
 
 	if (sip->sip_to)
@@ -159,11 +186,9 @@ static void new_call(struct sip_agent *agent, nua_handle_t *nh,
 		call_leg_release(&leg->base);
 		return;
 	}
-	struct in_addr net = { .s_addr = leg->base.ip };
-	inet_ntop(AF_INET, &net, ip_addr, sizeof(ip_addr));
 	LOGP(DSIP, LOGL_INFO, "SDP Extracted: IP=(%s) PORT=(%u) PAYLOAD=(%u).\n",
-		               ip_addr,
-		               leg->base.port,
+		               osmo_sockaddr_ntop((const struct sockaddr *)&leg->base.addr, ip_addr),
+		               osmo_sockaddr_port((const struct sockaddr *)&leg->base.addr),
 		               leg->base.payload_type);
 
 	leg->base.release_call = sip_release_call;
@@ -177,6 +202,8 @@ static void new_call(struct sip_agent *agent, nua_handle_t *nh,
 	nua_handle_bind(nh, leg);
 	leg->sdp_payload = talloc_strdup(leg, sip->sip_payload->pl_data);
 
+	call_leg_rx_sdp(&leg->base, sip_get_sdp(sip));
+
 	app_route_call(call,
 			talloc_strdup(leg, from),
 			talloc_strdup(leg, to));
@@ -186,9 +213,8 @@ static void sip_handle_reinvite(struct sip_call_leg *leg, nua_handle_t *nh, cons
 
 	char *sdp;
 	sdp_mode_t mode = sdp_sendrecv;
-	uint32_t ip = leg->base.ip;
-	uint16_t port = leg->base.port;
-	char ip_addr[INET_ADDRSTRLEN];
+	char ip_addr[INET6_ADDRSTRLEN];
+	struct sockaddr_storage prev_addr = leg->base.addr;
 
 	LOGP(DSIP, LOGL_INFO, "re-INVITE for call %s\n", sip->sip_call_id->i_id);
 
@@ -214,9 +240,11 @@ static void sip_handle_reinvite(struct sip_call_leg *leg, nua_handle_t *nh, cons
 		return;
 	}
 
-	struct in_addr net = { .s_addr = leg->base.ip };
-	inet_ntop(AF_INET, &net, ip_addr, sizeof(ip_addr));
-	LOGP(DSIP, LOGL_DEBUG, "pre re-INVITE have IP:port (%s:%u)\n", ip_addr, leg->base.port);
+	LOGP(DSIP, LOGL_DEBUG, "pre re-INVITE have IP:port (%s:%u)\n",
+	     osmo_sockaddr_ntop((struct sockaddr*)&prev_addr, ip_addr),
+	     osmo_sockaddr_port((struct sockaddr*)&prev_addr));
+
+	call_leg_rx_sdp(&leg->base, sip_get_sdp(sip));
 
 	if (mode == sdp_sendonly) {
 		/* SIP side places call on HOLD */
@@ -231,13 +259,20 @@ static void sip_handle_reinvite(struct sip_call_leg *leg, nua_handle_t *nh, cons
 			call_leg_release(&leg->base);
 			return;
 		}
-		struct in_addr net = { .s_addr = leg->base.ip };
-		inet_ntop(AF_INET, &net, ip_addr, sizeof(ip_addr));
-		LOGP(DSIP, LOGL_DEBUG, "Media IP:port in re-INVITE: (%s:%u)\n", ip_addr, leg->base.port);
-		if (ip != leg->base.ip || port != leg->base.port) {
-			LOGP(DSIP, LOGL_INFO, "re-INVITE changes media connection.\n");
+		LOGP(DSIP, LOGL_DEBUG, "Media IP:port in re-INVITE: (%s:%u)\n",
+		     osmo_sockaddr_ntop((struct sockaddr*)&leg->base.addr, ip_addr),
+		     osmo_sockaddr_port((struct sockaddr*)&leg->base.addr));
+		if (osmo_sockaddr_cmp((struct osmo_sockaddr *)&prev_addr,
+				      (struct osmo_sockaddr *)&leg->base.addr)) {
+			LOGP(DSIP, LOGL_INFO, "re-INVITE changes media connection to %s:%u\n",
+			     osmo_sockaddr_ntop((struct sockaddr*)&leg->base.addr, ip_addr),
+			     osmo_sockaddr_port((struct sockaddr*)&leg->base.addr));
 			if (other->update_rtp)
 				other->update_rtp(leg->base.call->remote);
+		} else {
+			LOGP(DSIP, LOGL_INFO, "re-INVITE does not change media connection (%s:%u)\n",
+			     osmo_sockaddr_ntop((struct sockaddr*)&prev_addr, ip_addr),
+			     osmo_sockaddr_port((struct sockaddr*)&prev_addr));
 		}
 		sdp = sdp_create_file(leg, other, sdp_sendrecv);
 	}
@@ -323,13 +358,15 @@ static int status2cause(int status)
 
 void nua_callback(nua_event_t event, int status, char const *phrase, nua_t *nua, nua_magic_t *magic, nua_handle_t *nh, nua_hmagic_t *hmagic, sip_t const *sip, tagi_t tags[])
 {
-	LOGP(DSIP, LOGL_DEBUG, "SIP event[%s] status(%d) phrase(%s) %p\n",
-		nua_event_name(event), status, phrase, hmagic);
+	LOGP(DSIP, LOGL_DEBUG, "SIP event[%s] status(%d) phrase(%s) SDP(%s) %p\n",
+		nua_event_name(event), status, phrase, sip_get_sdp(sip), hmagic);
 
 	if (event == nua_r_invite) {
 		struct sip_call_leg *leg;
 		leg = (struct sip_call_leg *) hmagic;
 
+		call_leg_rx_sdp(&leg->base, sip_get_sdp(sip));
+
 		/* MT call is moving forward */
 
 		/* The dialogue is now confirmed */
@@ -350,7 +387,12 @@ void nua_callback(nua_event_t event, int status, char const *phrase, nua_t *nua,
 		else if (status >= 300) {
 			struct call_leg *other = call_leg_other(&leg->base);
 
-			LOGP(DSIP, LOGL_INFO, "INVITE got status(%d), releasing leg(%p).\n", status, leg);
+			if (status < 400)
+				LOGP(DSIP, LOGL_NOTICE, "INVITE got status(%d), releasing leg(%p) as redirect is not"
+				     " implemented\n", status, leg);
+			else
+				LOGP(DSIP, LOGL_ERROR, "INVITE got status(%d), releasing leg(%p)\n", status, leg);
+
 			nua_cancel(leg->nua_handle, TAG_END());
 			nua_handle_destroy(leg->nua_handle);
 			call_leg_release(&leg->base);
@@ -366,8 +408,10 @@ void nua_callback(nua_event_t event, int status, char const *phrase, nua_t *nua,
 		 * respond to the re-INVITE query. */
 		if (sip->sip_payload && sip->sip_payload->pl_data) {
 			struct sip_call_leg *leg = sip_find_leg(nh);
-			if (leg)
+			if (leg) {
+				call_leg_rx_sdp(&leg->base, sip_get_sdp(sip));
 				sip_handle_reinvite(leg, nh, sip);
+			}
 		}
 	} else if (event == nua_r_bye || event == nua_r_cancel) {
 		/* our bye or hang up is answered */
@@ -393,10 +437,12 @@ void nua_callback(nua_event_t event, int status, char const *phrase, nua_t *nua,
 
 		if (status == 100) {
 			struct sip_call_leg *leg = sip_find_leg(nh);
-			if (leg)
+			if (leg) {
+				call_leg_rx_sdp(&leg->base, sip_get_sdp(sip));
 				sip_handle_reinvite(leg, nh, sip);
-			else
+			} else {
 				new_call((struct sip_agent *) magic, nh, sip);
+			}
 		}
 	} else if (event == nua_i_cancel) {
 		struct sip_call_leg *leg;
@@ -491,6 +537,7 @@ static void sip_ring_call(struct call_leg *_leg)
 	OSMO_ASSERT(_leg->type == CALL_TYPE_SIP);
 	leg = (struct sip_call_leg *) _leg;
 
+	/* 180 Ringing should not contain any SDP. */
 	nua_respond(leg->nua_handle, SIP_180_RINGING, TAG_END());
 }
 
@@ -599,6 +646,19 @@ static int send_invite(struct sip_agent *agent, struct sip_call_leg *leg,
 				agent->app->sip.remote_port);
 	char *sdp = sdp_create_file(leg, other, sdp_sendrecv);
 
+	/* Encode the Global Call Reference (if present) */
+	char *x_gcr = NULL;
+
+	if (leg->base.call->gcr_present) {
+		struct msgb *msg = msgb_alloc(16, "SIP GCR");
+
+		if (msg != NULL && osmo_enc_gcr(msg, &leg->base.call->gcr) > 0)
+			x_gcr = talloc_asprintf(leg, "X-Global-Call-Ref: %s", msgb_hexdump(msg));
+		else
+			LOGP(DSIP, LOGL_ERROR, "Failed to encode GCR for leg(%p)\n", leg);
+		msgb_free(msg);
+	}
+
 	leg->state = SIP_CC_INITIAL;
 	leg->dir = SIP_DIR_MT;
 	nua_invite(leg->nua_handle,
@@ -606,6 +666,7 @@ static int send_invite(struct sip_agent *agent, struct sip_call_leg *leg,
 			SIPTAG_TO_STR(to),
 			NUTAG_MEDIA_ENABLE(0),
 			SIPTAG_CONTENT_TYPE_STR("application/sdp"),
+			TAG_IF(x_gcr, SIPTAG_HEADER_STR(x_gcr)),
 			SIPTAG_PAYLOAD_STR(sdp),
 			TAG_END());
 
@@ -613,6 +674,7 @@ static int send_invite(struct sip_agent *agent, struct sip_call_leg *leg,
 	talloc_free(from);
 	talloc_free(to);
 	talloc_free(sdp);
+	talloc_free(x_gcr);
 	return 0;
 }
 
@@ -666,7 +728,19 @@ static void sip_logger(void *stream, char const *fmt, va_list ap)
 	 * the log handler call-back function, so we have no clue what log level the
 	 * currently logged message was sent for :(  As a result, we can only use one
 	 * hard-coded LOGL_NOTICE here */
-	osmo_vlogp(DSIP, LOGL_NOTICE, "", 0, 0, fmt, ap);
+	if (!log_check_level(DSIP, LOGL_NOTICE))
+		return;
+	/* The sofia-sip log line *sometimes* lacks a terminating '\n'. Add it. */
+	char log_line[256];
+	int rc = vsnprintf(log_line, sizeof(log_line), fmt, ap);
+	if (rc > 0) {
+		/* since we're explicitly checking for sizeof(log_line), we can use vsnprintf()'s return value (which,
+		 * alone, would possibly cause writing past the buffer's end). */
+		char *end = log_line + OSMO_MIN(rc, sizeof(log_line) - 2);
+		osmo_strlcpy(end, "\n", 2);
+		LOGP(DSIP, LOGL_NOTICE, "%s", log_line);
+	} else
+		LOGP(DSIP, LOGL_NOTICE, "unknown logging from sip\n");
 }
 
 void sip_agent_init(struct sip_agent *agent, struct app_config *app)

tests/Makefile.am

@@ -1,9 +1,9 @@
 if ENABLE_EXT_TESTS
-python-tests: $(BUILT_SOURCES)
+python-tests: $(top_builddir)/src/osmo-sip-connector
 	osmotestvty.py -p $(abs_top_srcdir) -w $(abs_top_builddir) -v
 	osmotestconfig.py -p $(abs_top_srcdir) -w $(abs_top_builddir) -v
 else
-python-tests: $(BUILT_SOURCES)
+python-tests:
 	echo "Not running python-based tests (determined at configure-time)"
 endif