gtp/gtp_internal.h: new file

While at it, move internal functions of gtp.h to a separate file too. The following APIs are unexpectedly public: * imsi_gtp2str gets used by pdp.h * gsna2in_addr, gtp_echo_req gets used by osmo-sgsn Change-Id: I72c40cbdec33449ca8104fb3cad8df1a9e07dfd7
gtp/gsn_internal.h: new file
2025-11-03 13:43:25 +00:00 · 2024-05-13 14:30:10 +02:00 · 2024-05-13 14:30:04 +02:00 · 2024-05-13 14:19:36 +02:00 · 2024-03-23 16:32:45 +01:00 · 2024-03-23 16:15:42 +01:00
72 changed files with 9791 additions and 3263 deletions
--- a/.github/FUNDING.yml
+++ b/.github/FUNDING.yml
@@ -0,0 +1 @@
+open_collective: osmocom
--- a/.gitignore
+++ b/.gitignore
@@ -27,7 +27,7 @@ osmo-ggsn-*.tar*
 # debian
 debian/osmo-ggsn/
 debian/*.debhelper
-debian/libgtp1
+debian/libgtp*/
 debian/osmo-ggsn-dbg
 debian/*.log
 debian/autoreconf.*
@@ -79,5 +79,10 @@ doc/manuals/generated/
 doc/manuals/osmomsc-usermanual.xml
 doc/manuals/common
 doc/manuals/build
+doc/manuals/vty/ggsn_vty_reference.xml

 contrib/osmo-ggsn.spec
+/debian/gtp-echo-responder-dbg/
+/debian/gtp-echo-responder/
+/debian/osmo-ggsn-doc/
+/utils/gtp-echo-responder
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,5 +1,15 @@
 ## Process this file with automake to produce Makefile.in
-SUBDIRS = lib gtp ggsn sgsnemu doc contrib tests
+SUBDIRS = \
+	  include \
+	  lib \
+	  gtp \
+	  ggsn \
+	  sgsnemu \
+	  doc \
+	  contrib \
+	  utils \
+	  tests \
+	  $(NULL)

 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = libgtp.pc
--- a/README.md
+++ b/README.md
@@ -5,57 +5,71 @@ This repository contains a C-language implementation of a GGSN (Gateway
 GPRS Support Node), a core network element of ETSI/3GPP cellular
 networks such as GPRS, EDGE, UMTS or HSPA.

-OsmoGGSN is part of the [Osmocom](https://osmocom.org/) Open Source
-Mobile Communications projects and the successor to OpenGGSN.
-OpenGGSN was developed until 2004 by Mondru AB.
+**OsmoGGSN** is part of the [Osmocom](https://osmocom.org/) Open Source
+Mobile Communications projects and the successor to OpenGGSN (which was
+developed until 2004 by Mondru AB).

 Homepage
 --------

-The official homepage of the project is
-https://osmocom.org/projects/openggsn/wiki
+The official homepage of the project is <https://osmocom.org/projects/openggsn/wiki>.

 GIT Repository
 --------------

 You can clone from the official osmo-ggsn.git repository using

-	git clone git://git.osmocom.org/osmo-ggsn.git
+	git clone https://gitea.osmocom.org/cellular-infrastructure/osmo-ggsn

-There is a cgit interface at http://git.osmocom.org/osmo-ggsn/
+There is a web interface at <https://gitea.osmocom.org/cellular-infrastructure/osmo-ggsn>

 Documentation
 -------------

-There currently is no other documentation other than the wiki on the
-homepage.  It would be great if somebody would work towards a user
-manual that can become part of the osmo-gsm-manuals project.
+The user manual and VTY reference are optionally built in PDF form
+as part of the build process. Pre-rendered versions are available here:
+
+* [osmo-ggsn user manual](https://ftp.osmocom.org/docs/osmo-ggsn/master/osmoggsn-usermanual.pdf)
+* [osmo-ggsn VTY reference](https://ftp.osmocom.org/docs/osmo-ggsn/master/osmoggsn-vty-reference.pdf)
+
+Forum
+-----
+
+We welcome any pySim related discussions in the
+[Cellular Network Infrastructure -> 2G/3G Core Network](https://discourse.osmocom.org/c/cni/2g-3g-cn/)
+section of the osmocom discourse (web based Forum).

 Mailing List
 ------------

 Discussions related to OsmoGGSN are happening on the
 osmocom-net-gprs@lists.osmocom.org mailing list, please see
-https://lists.osmocom.org/mailman/listinfo/osmocom-net-gprs for
+<https://lists.osmocom.org/mailman/listinfo/osmocom-net-gprs> for
 subscription options and the list archive.

-Please observe the [Osmocom Mailing List
-Rules](https://osmocom.org/projects/cellular-infrastructure/wiki/Mailing_List_Rules)
+Please observe the [Osmocom Mailing List Rules](https://osmocom.org/projects/cellular-infrastructure/wiki/Mailing_List_Rules)
 when posting.

+Issue Tracker
+-------------
+
+We use the [issue tracker of the osmo-ggsn project on osmocom.org](https://osmocom.org/projects/openggsn/issues) for
+tracking the state of bug reports and feature requests.  Feel free to submit any issues you may find, or help
+us out by resolving existing issues.
+
 Contributing
 ------------

 Our coding standards are described at
-https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards
+<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
+<https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit> for
 more details

 The current patch queue for OsmoGGSN can be seen at
-https://gerrit.osmocom.org/#/q/project:osmo-ggsn+status:open
+<https://gerrit.osmocom.org/#/q/project:osmo-ggsn+status:open>


 QuickStart
@@ -75,61 +89,33 @@ The tun driver is required for proper operation of openggsn. For Linux
 kernels later than 2.4.7 the driver is typically included, but might
 need to be configured for automatic loading:

-1. Add the following line to /etc/modules.conf: alias char-major-10-200 tun 
-2. depmod -a
+1. Add the following line to `/etc/modules.conf`: `alias char-major-10-200 tun`
+2. `depmod -a`


 Installation from binary
 ------------------------

-OsmoGGSN is built for common versions of Debian and Ubuntu as part of
+OsmoGGSN is built for common versions of Debian, Ubuntu and other distributions part of
 the [Osmocom Nightly Builds](https://osmocom.org/projects/cellular-infrastructure/wiki/Nightly_Builds)
-project.  If you don't want to do development, it is suggested to simply
-use those binary packages, rather than building yourself from source.
+and [Osmocom Latest Builds](https://osmocom.org/projects/cellular-infrastructure/wiki/Latest_Builds).
+If you don't want to do development, it is suggested to simply use those binary packages, rather than building
+yourself from source.


 Installation from source
 ------------------------

-1. ./configure
-2. make
-3. make install
+```
+./configure
+make
+make install
+```

 You need to be root in order to install the package, but not in order
 to compile.


-Running
-------
-
-*sgsnemu*
-Start the emulator as root using the command:
-
-  sgsnemu -l 10.0.0.50 -r 10.0.0.40 --createif --defaultroute
-
-This will cause the sgsn emulator to bind to local address 10.0.0.50
-and connect to the ggsn found at 10.0.0.40. It will first send off an
-ECHO_REQUEST message. After this it will attempt to establish a pdp
-context. If successful it will create a local interface and set up
-routing. Now you should be able to ping through the connection. Use a
-network analysator such as ethereal to monitor the traffic.
-
-sgsnemu -h will show a list of available options. 
-
-sgsnemu -c sgsnemu.conf will use sgsnemu.conf as a configuration
-file. A sample file is provided in examples/sgsnemu.conf.
-
-*ggsn*
-Edit the configuration file ggsn.conf found under openggsn/examples.
-Start the ggsn as root using the command:
-
-ggsn --fg -c examples/ggsn.conf -l 10.0.0.40 --statedir ./
-
-This will run the ggsn in foreground using the local interface
-10.0.0.40. If you don't have a GSM network available for testing you
-can use sgsnemu to test the GGSN.
-
-
 Support
 -------

@@ -144,9 +130,10 @@ OsmoGGSN is an open source implementation of GPRS Support Nodes
 version 1.

 OsmoGGSN provides 3 components:
- * gtplib
- * osmo-ggsn
- * sgsnemu
+
+ * *libgtp*, a shared library for the GTPv1C protocol
+ * *osmo-ggsn*, the GGSN itself
+ * *sgsnemu*, a SGSN emulator

 *gtplib*
 This library contains all functionality relating to the GTP
@@ -182,10 +169,10 @@ Both osmo-ggsn and sgsnemu uses the tun package. You need at least tun
 version 1.1. With Linux tun is normally included from kernel version
 2.4.7. To configure automatic loading:

-1. Add the following line to /etc/modules.conf: alias char-major-10-200 tun 
-2. depmod -a
+1. Add the following line to `/etc/modules.conf`: `alias char-major-10-200 tun`
+2. `depmod -a`

-Alternatively you can execute "modprobe tun" on the commandline.
+Alternatively you can execute `modprobe tun` on the commandline.

 Gengetopt
 ---------
@@ -195,11 +182,13 @@ cmdline.ggo source file. You need at least gengetopt version 2.8. If
 you are just going to compile the programs you don't need gengetopt.

 To use gengetopt for the sgsnemu do the following:
+```
 cd sgsnemu
 gengetopt < cmdline.ggo --conf-parser
+```

 For more information about gengetopt see
-http://www.gnu.org/software/gengetopt/gengetopt.html
+<http://www.gnu.org/software/gengetopt/gengetopt.html>


 Compilation and Installation
@@ -213,27 +202,21 @@ Running osmo-ggsn

 Use osmo-ggsn -h for a list of available options. All options available on
 the command line can also be given in a configuration file. See
-examples/osmo-ggsn.cfg for the format of this file.
+`doc/examples/osmo-ggsn.cfg` for the format of this file.

 Start osmo-ggsn as root using the command:

-osmo-ggsn -c examples/osmo-ggsn.cfg
+`osmo-ggsn -c doc/examples/osmo-ggsn.cfg`

-First a tun network interface will be created. In the above example
-the network interface address is 192.168.0.0 and the mask is
-255.255.255.0. You can check that this interface is up by using
-ifconfig.
+First, a tun network interface will be created for each configured apn.

 After tun has been successfully established the ggsn will wait for GTP
-create PDP context requests on the local interface
-10.0.0.40. Currently all requests are accepted, and no password,
-username or APN validation is performed.
+create PDP context requests on the configured `gtp bind-ip` address.
+Currently all requests are accepted, and no password, username validation is performed.

-When receiving a create PDP context request a dynamic IP address will
-be allocated from the address pool determined by --dynip. In the above
-example the first allocated address will be 192.168.0.1, followed by
-192.168.0.2 and so on. The request is confirmed by sending a create
-PDP context response message to the peer (SGSN).
+When receiving a create PDP context request for a given APN, a dynamic IP address will
+be allocated from the address pool defined in the config file section for that apn.
+The request is confirmed by sending a create PDP context response message to the peer (SGSN).

 Now IP packets will be forwarded between the tun network interface and
 the established GTP tunnel. In order to allow users to access the
@@ -241,22 +224,22 @@ external network routing needs to be set up. If private addresses are
 used you need to configure network address translation. See the Linux
 Networking HOWTO for details.

-Remember to enable routing: 
+Remember to enable routing:

-echo 1 > /proc/sys/net/ipv4/ip_forward
+`echo 1 > /proc/sys/net/ipv4/ip_forward`

-If you installed using a binary RPM package it is possible to start
-osmo-ggsn by using the Sys 5 script:
+If you're using systemd and did `make install` or installed from a bianry package,
+you can start osmo-ggsn by using the included systemd service/unit file:

-/etc/init.d/osmo-ggsn start
+`systemctl start osmo-ggsn`


 Running sgsnemu
 ===============

-Use sgsnemu -h for a list of available options. All options available
+Use `sgsnemu -h` for a list of available options. All options available
 on the command line can also be given in a configuration file. See
-examples/sgsnemu.conf for the format of this file.
+`doc/examples/sgsnemu.conf` for the format of this file.

 If you want to test a GRX roaming connection you will need to do the
 following:
@@ -269,11 +252,11 @@ subnet mask and default route. See the Linux Networking HOWTO for
 details.
 4. Launch sgsnemu with something like:

-sgsnemu --listen 10.0.0.50 --remote 10.0.0.40 --dns 10.20.38.51 --timelimit 10 --contexts 0 
+`sgsnemu --listen 10.0.0.50 --remote 10.0.0.40 --dns 10.20.38.51 --timelimit 10 --contexts 0`

 sgsnemu will print something like the following on the screen:

-
+```
  Using DNS server:      10.20.38.51 (10.20.38.51)
  Local IP address is:   10.0.0.50 (10.0.0.50)
  Remote IP address is:  10.0.0.40 (10.0.0.40)
@@ -289,6 +272,7 @@ sgsnemu will print something like the following on the screen:
  Waiting for response from ggsn........

  Received echo response. Cause value: 0
+```

 This is quite good. It means that you managed to send off an echo
 request to a remote GGSN, and it was friendly enough to answer you. If
@@ -306,10 +290,11 @@ testing. Also note that you are establishing a connection to the Gi
 network, so please be carefull not to route internet traffic onto the
 GPRS core network! Assuming you know what you are doing:

-sgsnemu --listen 10.0.0.50 --remote 10.0.0.40 --dns 10.20.38.51 --timelimit 10 --contexts 1 --apn internet --imsi 240011234567890 --msisdn 46702123456 --createif --defaultroute
+`sgsnemu --listen 10.0.0.50 --remote 10.0.0.40 --dns 10.20.38.51 --timelimit 10 --contexts 1 --apn internet --imsi 240011234567890 --msisdn 46702123456 --createif --defaultroute`

 sgsnemu will print something like the following on the screen:

+```
  Using DNS server:      10.20.38.51 (10.20.38.51)
  Local IP address is:   10.0.0.50 (10.0.0.50)
  Remote IP address is:  10.0.0.40 (10.0.0.40)
@@ -330,7 +315,7 @@ sgsnemu will print something like the following on the screen:
  Setting up interface and routing
  /sbin/ifconfig tun0 192.168.0.1
  /sbin/route add -net 192.168.0.0 netmask 255.255.255.0 gw 192.168.0.1
-
+```

 Now a context is established to the remote GGSN. The IP address of the
 context is 192.168.0.1. You should be able to ping a known address on
@@ -344,13 +329,13 @@ do this is to use policy routing. Also note that you are effectively
 connecting the same computer to both the Gn and Gi network, so please
 be carefull not to route internet traffic onto the GPRS core network
 and please protect yourself against hackers! For this reason it is
-advised to always use --contexts 0 when testing a live network.
+advised to always use `--contexts 0` when testing a live network.

-After --timelimit seconds the PDP context is disconnected with the
+After `--timelimit seconds` the PDP context is disconnected with the
 following messages from sgsnemu:

-
+```
  Disconnecting PDP context #0
  Received delete PDP context response. Cause value: 128
  Deleting tun interface
-
+```
--- a/2
+++ b/2
@@ -7,3 +7,5 @@
 # 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
+libgtp		REMOVE		remove GTP cause defines of reserved values
+libgtpnl > 1.2.5		gtp_tunnel_set_family()
--- a/configure.ac
+++ b/configure.ac
@@ -9,6 +9,8 @@ AC_CONFIG_AUX_DIR([.])
 AC_CONFIG_TESTDIR(tests)
 AC_CANONICAL_HOST

+CFLAGS="$CFLAGS -std=gnu11"
+
 dnl kernel style compile messages
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])

@@ -19,7 +21,7 @@ AC_PROG_AWK
 AC_PROG_CPP
 LT_INIT

-dnl patching ${archive_cmds} to affect generation of file "libtool" to fix linking with clang 
+dnl patching ${archive_cmds} to affect generation of file "libtool" to fix linking with clang
 AS_CASE(["$LD"],[*clang*],
  [AS_CASE(["${host_os}"],
     [*linux*],[archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'])])
@@ -152,9 +154,9 @@ adl_FUNC_GETOPT_LONG

 AM_INIT_AUTOMAKE([foreign])

-PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore >= 1.1.0)
-PKG_CHECK_MODULES(LIBOSMOVTY, libosmovty >= 1.1.0)
-PKG_CHECK_MODULES(LIBOSMOCTRL, libosmoctrl >= 1.1.0)
+PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore >= 1.9.0)
+PKG_CHECK_MODULES(LIBOSMOVTY, libosmovty >= 1.9.0)
+PKG_CHECK_MODULES(LIBOSMOCTRL, libosmoctrl >= 1.9.0)

 AC_ARG_ENABLE(sanitize,
 	[AS_HELP_STRING(
@@ -255,14 +257,18 @@ AC_CONFIG_FILES([Makefile
                 lib/Makefile
                 intl/Makefile
                 po/Makefile
+                 utils/Makefile
                 sgsnemu/Makefile
-    doc/manuals/Makefile
+                 doc/manuals/Makefile
                 contrib/Makefile
                 contrib/systemd/Makefile
                 contrib/osmo-ggsn.spec
                 tests/Makefile
                 tests/lib/Makefile
                 tests/gtp/Makefile
+                 include/Makefile
+                 include/osmocom/Makefile
+                 include/osmocom/gtp/Makefile
                 libgtp.pc])
 AC_OUTPUT

--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -38,7 +38,6 @@ 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

@@ -54,11 +53,11 @@ cd "$base"
 autoreconf --install --force
 ./configure --enable-sanitize --enable-werror $GTP $CONFIG
 $MAKE $PARALLEL_MAKE
-DISTCHECK_CONFIGURE_FLAGS="$CONFIG" $MAKE distcheck
+DISTCHECK_CONFIGURE_FLAGS="$CONFIG" $MAKE $PARALLEL_MAKE distcheck

 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
--- a/contrib/osmo-ggsn.spec.in
+++ b/contrib/osmo-ggsn.spec.in
@@ -29,11 +29,10 @@ BuildRequires:  pkgconfig >= 0.20
 %if 0%{?suse_version}
 BuildRequires:  systemd-rpm-macros
 %endif
-BuildRequires:  pkgconfig(libgtpnl) >= 1.0.0
-BuildRequires:  pkgconfig(libmnl) >= 1.0.3
-BuildRequires:  pkgconfig(libosmocore) >= 1.1.0
-BuildRequires:  pkgconfig(libosmoctrl) >= 1.1.0
-BuildRequires:  pkgconfig(libosmovty) >= 1.1.0
+BuildRequires:  pkgconfig(libgtpnl) >= 1.2.0
+BuildRequires:  pkgconfig(libosmocore) >= 1.9.0
+BuildRequires:  pkgconfig(libosmoctrl) >= 1.9.0
+BuildRequires:  pkgconfig(libosmovty) >= 1.9.0
 Obsoletes:      openggsn
 %{?systemd_requires}

@@ -62,6 +61,15 @@ libgtp implements the GPRS Tunneling Protocol between SGSN and GGSN.
 This subpackage contains libraries and header files for developing
 applications that want to make use of libgtp.

+%package -n gtp-echo-responder
+Summary:        Small program answering GTP ECHO Request with GTP ECHO Response
+License:        MIT
+Group:          System/Libraries
+
+%description -n gtp-echo-responder
+Small program answering GTP ECHO Request with GTP ECHO Response for both GTPCv1
+and GTPCv2.
+
 %prep
 %setup -q

@@ -69,6 +77,7 @@ applications that want to make use of libgtp.
 echo "%{version}" >.tarball-version
 autoreconf -fi
 %configure \
+  --enable-gtp-linux \
  --disable-static \
  --docdir="%{_docdir}/%{name}" \
  --with-systemdsystemunitdir=%{_unitdir} \
@@ -108,7 +117,9 @@ make %{?_smp_mflags} check || (find . -name testsuite.log -exec cat {} +)
 %{_mandir}/man8/sgsnemu.8%{?ext_man}
 %{_unitdir}/%{name}.service
 %dir %{_docdir}/%{name}/examples
+%{_docdir}/%{name}/examples/osmo-ggsn-kernel-gtp.cfg
 %{_docdir}/%{name}/examples/osmo-ggsn.cfg
+%{_docdir}/%{name}/examples/sgsnemu.conf
 %dir %{_sysconfdir}/osmocom
 %config(noreplace) %{_sysconfdir}/osmocom/osmo-ggsn.cfg

@@ -120,4 +131,7 @@ make %{?_smp_mflags} check || (find . -name testsuite.log -exec cat {} +)
 %{_libdir}/libgtp.so
 %{_libdir}/pkgconfig/libgtp.pc

+%files -n gtp-echo-responder
+%{_bindir}/gtp-echo-responder
+
 %changelog
--- a/contrib/systemd/osmo-ggsn.service
+++ b/contrib/systemd/osmo-ggsn.service
@@ -1,10 +1,13 @@
 [Unit]
 Description=OsmoGGSN
-After=networking.service
+After=network-online.target
+Wants=network-online.target

 [Service]
 Type=simple
 Restart=always
+StateDirectory=osmocom
+WorkingDirectory=%S/osmocom
 ExecStart=/usr/bin/osmo-ggsn -c /etc/osmocom/osmo-ggsn.cfg
 RestartSec=2
 RestartPreventExitStatus=1
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,155 @@
+osmo-ggsn (1.11.0) unstable; urgency=medium
+
+  [ Daniel Willmann ]
+  * gtp: Add net GTP cause values and a function to check for success
+
+ -- Oliver Smith <osmith@sysmocom.de>  Tue, 28 Nov 2023 13:38:29 +0100
+
+osmo-ggsn (1.10.2) unstable; urgency=medium
+
+  [ Vadim Yanitskiy ]
+  * Do not hard-code -g and -O2 in CFLAGS
+  * tests: use -no-install libtool flag to avoid ./lt-* scripts
+
+  [ Oliver Smith ]
+  * doc/manuals/chapters/configuration: fix typo
+  * debian: set compat level to 10
+  * systemd: depend on networking-online.target
+  * README: update documentation section
+  * doc: running: update kernel-gtp limitations
+  * lib/in46_addr: add in46a_from_gsna
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 12 Sep 2023 14:36:10 +0200
+
+osmo-ggsn (1.10.1) unstable; urgency=medium
+
+  [ Oliver Smith ]
+  * debian/libgtp6.shlibs: new file
+
+  [ Vadim Yanitskiy ]
+  * lib/icmpv6.h: fix struct icmpv6_{radv_hdr,opt_prefix}
+  * gtp/gsn.c: fix 'No newline at end of file'
+  * gtp: use OSMO_ASSERT() in gtp_new()
+
+ -- Vadim Yanitskiy <vyanitskiy@sysmocom.de>  Mon, 27 Feb 2023 22:35:47 +0700
+
+osmo-ggsn (1.10.0) unstable; urgency=medium
+
+  [ Max ]
+  * Set working directory in systemd service file
+  * Ignore .deb build byproducts
+  * ctrl: take both address and port from vty config
+
+  [ Pau Espin Pedrol ]
+  * cosmetic: gtp: Fix typo in comment
+  * Split gsn_t related APIs out of gtp.{c,h}
+  * Use rate_ctr for gsn_t available_counters
+  * ggsn: Introduce tdef and make it configurable over VTY
+  * gtp: Introduce VTY configurable GTP timer X3
+  * Fix typos in comments and VTY descriptions
+
+  [ arehbein ]
+  * osmo-ggsn: Transition to use of 'telnet_init_default'
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 07 Feb 2023 14:29:48 +0100
+
+osmo-ggsn (1.9.0) unstable; urgency=medium
+
+  [ Pau Espin Pedrol ]
+  * tests: in46a_test: Make coverity happy when calling in46a_from_eua
+  * vty: Fix cmd 'no echo-interval' doing nothing
+  * libgtp: Fix ggsn crash if pdp alloc array is full (PDP_MAX)
+  * libgtp: Define retransmit QUEUE_SIZE relative to PDP_MAX (increase)
+  * gtp: Use switch statement in gtp_create_pdp_ind()
+  * gtp: Log detection of rx duplicate
+  * gtp: Small log improvements in gtp_create_pdp_ind()
+  * gtp: Specify retrans queue name & seqnum in log lines
+  * gtp: Log retrans queue register&free entries
+  * gtp: Fix typo in comment
+  * pco.h: Fix typo in reference to spec
+
+  [ Vadim Yanitskiy ]
+  * tests: use 'check_PROGRAMS' instead of 'noinst_PROGRAMS'
+
+  [ Harald Welte ]
+  * update git URLs (git -> https; gitea)
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 28 Jun 2022 17:48:22 +0200
+
+osmo-ggsn (1.8.0) unstable; urgency=medium
+
+  [ Oliver Smith ]
+  * doc/examples/Makefile.am: add sgsnemu.conf
+  * doc/examples/osmo-ggsn-kernel-gtp.cfg: new file
+  * doc/manuals: describe GTP-U kernel module
+  * gitignore: add ggsn_vty_reference.xml
+
+  [ Harald Welte ]
+  * Don't install osmo-ggsn-kernel-gtp.cfg to /etc/osmocom/
+  * Don't install sgsnemu.conf to /etc/osmocom/
+  * ggsn: Reject PDP CTX ACT for static IP addresses
+  * vty: Inform user that static IP addresses are not supported
+
+  [ Pau Espin Pedrol ]
+  * gtp: Update teic_confirmed only on resp success
+  * gtp: Rework parsing logic of UpdatePdpCtxResponse
+  * ggsn: Improve logging on incoming DL data packets
+  * gtp: Improve logging of failing pdp ctx resolution from TEI/TID
+  * cosmetic: gtpie.c: Fix trailing whitespace
+  * gtp: constify pointer arg
+  * gtp: Support tx/rx RAN Information Relay message
+  * ggsn: Log tun fd write errors
+  * ggsn: Fix heap-use-after-free during Recovery without associated PDP
+  * cosmetic: configure.ac: Fix tabulation in line
+  * Introduce program gtp-echo-responder
+  * gtp_echo_responder: report invalid chars present in node-feautres cmdline arg as error
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 16 Nov 2021 13:49:16 +0100
+
+osmo-ggsn (1.7.1) unstable; urgency=medium
+
+  [ Harald Welte ]
+  * main: add --vty-ref-mode, use vty_dump_xml_ref_mode()
+  * manuals: generate vty reference xml at build time
+
+ -- Pau Espin Pedrol <pespin@sysmocom.de>  Tue, 23 Feb 2021 17:31:24 +0100
+
+osmo-ggsn (1.7.0) unstable; urgency=medium
+
+  [ Vadim Yanitskiy ]
+  * debian/control: change maintainer to the Osmocom team / mailing list
+
+  [ Pau Espin Pedrol ]
+  * configure.ac: Fix trailing whitespace
+  * doc: Update VTY reference xml file
+  * Support setting rt-prio and cpu-affinity mask through VTY
+  * contrib/jenkins: Enable parallel make in make distcheck
+  * ggsn: generate coredump and exit upon SIGABRT received
+  * tests: Explicitly drop category from log
+  * tests: Replace deprecated API log_set_print_filename
+
+  [ Keith ]
+  * Fix vty PDP lookups by IMSI
+  * Prevent Crash in show pdp-context from vty
+  * Minor: remove code duplication
+  * Use imsi_str2gtp() in sgsnemu
+  * sgsnemu: relax check on length of IMSI cmdline arg.
+  * GTP: Replace recently introduced imsi_str2gtp()
+
+  [ Harald Welte ]
+  * Use OSMO_FD_* instead of deprecated BSC_FD_*
+  * gtp-kernel: Remove duplicate #include section
+  * gtp-kernel: don't #include libmnl headers
+
+  [ Oliver Smith ]
+  * contrib/jenkins: don't build osmo-gsm-manuals
+  * configure.ac: set -std=gnu11
+  * apn_start: avoid segfault if missing tun-device
+  * .gitignore: ignore debian/libgtp*
+  * deb/rpm: build with --enable-gtp-linux
+
+ -- Pau Espin Pedrol <pespin@espeweb.net>  Tue, 23 Feb 2021 13:34:39 +0100
+
 osmo-ggsn (1.6.0) unstable; urgency=medium

  [ Pau Espin Pedrol ]
--- a/debian/compat
+++ b/debian/compat
@@ -1 +1 @@
-9
+10
--- a/debian/control
+++ b/debian/control
@@ -1,17 +1,18 @@
 Source: osmo-ggsn
-Maintainer: Harald Welte <laforge@gnumonks.org>
+Maintainer: Osmocom team <openbsc@lists.osmocom.org>
 Section: net
 Priority: optional
-Build-Depends: debhelper (>= 9),
+Build-Depends: debhelper (>= 10),
               autotools-dev,
               pkg-config,
               libdpkg-perl, git,
               dh-autoreconf,
-               libosmocore-dev (>= 1.1.0),
-               osmo-gsm-manuals-dev
+               libosmocore-dev (>= 1.9.0),
+               osmo-gsm-manuals-dev,
+               libgtpnl-dev (>= 1.2.0)
 Standards-Version: 3.9.6
-Vcs-Browser: http://git.osmocom.org/osmo-ggsn/
-Vcs-Git: git://git.osmocom.org/osmo-ggsn
+Vcs-Browser: https://gitea.osmocom.org/cellular-infrastructure/osmo-ggsn
+Vcs-Git: https://gitea.osmocom.org/cellular-infrastructure/osmo-ggsn
 Homepage: https://projects.osmocom.org/projects/openggsn

 Package: osmo-ggsn
@@ -37,6 +38,12 @@ Description: library implementing the GTP protocol between SGSN and GGSN
 This library is part of OsmoGGSN and implements the GTP protocol between
 SGSN (Serving GPRS support node) and GGSN.

+Package: gtp-echo-responder
+Architecture: any
+Depends: ${shlibs:Depends},
+         ${misc:Depends}
+Description: Small program answering GTP ECHO Request with GTP ECHO Response
+
 Package: libgtp-dev
 Architecture: any
 Multi-Arch: same
@@ -62,6 +69,15 @@ Description: Debug symbols for OsmoGGSN
 operators as the interface between the Internet and the rest of the
 mobile network infrastructure.

+Package: gtp-echo-responder-dbg
+Section: debug
+Architecture: any
+Priority: extra
+Depends: ${shlibs:Depends}, ${misc:Depends}, gtp-echo-responder (= ${binary:Version})
+Multi-Arch: same
+Description: Debug symbols for gtp-echo-responder
+ Small program answering GTP ECHO Request with GTP ECHO Response.
+
 Package: libgtp-dbg
 Section: debug
 Architecture: any
--- a/debian/copyright
+++ b/debian/copyright
@@ -16,6 +16,11 @@ Files: lib/getopt.c
 Copyright: 1987-2001 Free Software Foundation, Inc.
 License: LGPL-2.1+

+Files: utils/gtp_echo_responder.c
+       utils/gtp_echo_responder_test.py
+Copyright: 2021 sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+License: MIT
+
 Files: debian/*
 Copyright: 2010-2017  Harald Welte <laforge@gnumonks.org>
           2016       Ruben Undheim <ruben.undheim@gmail.com>
--- a/debian/gtp-echo-responder.install
+++ b/debian/gtp-echo-responder.install
@@ -0,0 +1 @@
+/usr/bin/gtp-echo-responder
--- a/debian/libgtp6.shlibs
+++ b/debian/libgtp6.shlibs
@@ -0,0 +1,2 @@
+# Most recent version of the package that added new symbols (OS#5318)
+libgtp 6 libgtp6 (>= 1.8.0)
--- a/debian/osmo-ggsn.examples
+++ b/debian/osmo-ggsn.examples
@@ -1,2 +1,3 @@
 doc/examples/osmo-ggsn.cfg
+doc/examples/osmo-ggsn-kernel-gtp.cfg
 doc/examples/sgsnemu.conf
--- a/debian/rules
+++ b/debian/rules
@@ -19,7 +19,10 @@ override_dh_strip:
 	dh_strip -plibgtp6 --dbg-package=libgtp-dbg

 override_dh_auto_configure:
-	dh_auto_configure -- --with-systemdsystemunitdir=/lib/systemd/system --enable-manuals
+	dh_auto_configure -- \
+		--enable-gtp-linux \
+		--with-systemdsystemunitdir=/lib/systemd/system \
+		--enable-manuals

 # Don't create .pdf.gz files (barely saves space and they can't be opened directly by most pdf readers)
 override_dh_compress:
--- a/doc/examples/Makefile.am
+++ b/doc/examples/Makefile.am
@@ -1,9 +1,13 @@
+OSMOCONF_FILES = \
+	osmo-ggsn.cfg \
+	$(NULL)
+
 osmoconfdir = $(sysconfdir)/osmocom
-osmoconf_DATA = osmo-ggsn.cfg
+osmoconf_DATA = $(OSMOCONF_FILES)

-EXTRA_DIST = osmo-ggsn.cfg
+EXTRA_DIST = $(OSMOCONF_FILES)

-CFG_FILES = find $(srcdir) -name '*.cfg*' | sed -e 's,^$(srcdir),,'
+CFG_FILES = find $(srcdir) -name '*.cfg' -o -name '*.conf' | sed -e 's,^$(srcdir),,'

 dist-hook:
 	for f in $$($(CFG_FILES)); do \
--- a/doc/examples/osmo-ggsn-kernel-gtp.cfg
+++ b/doc/examples/osmo-ggsn-kernel-gtp.cfg
@@ -0,0 +1,51 @@
+!
+! OpenGGSN (0.94.1-adac) configuration saved from vty
+!!
+!
+log stderr
+ logging filter all 1
+ logging color 1
+ logging print category 0
+ logging timestamp 0
+ logging level ip info
+ logging level tun info
+ logging level ggsn info
+ logging level sgsn notice
+ logging level icmp6 notice
+ logging level lglobal notice
+ logging level llapd notice
+ logging level linp notice
+ logging level lmux notice
+ logging level lmi notice
+ logging level lmib notice
+ logging level lsms notice
+ logging level lctrl notice
+ logging level lgtp info
+ logging level lstats notice
+ logging level lgsup notice
+ logging level loap notice
+ logging level lss7 notice
+ logging level lsccp notice
+ logging level lsua notice
+ logging level lm3ua notice
+ logging level lmgcp notice
+!
+stats interval 5
+!
+line vty
+ no login
+!
+ggsn ggsn0
+ gtp state-dir /tmp
+ gtp bind-ip 127.0.0.2
+ apn internet
+  gtpu-mode kernel-gtp
+  tun-device tun4
+  type-support v4
+  ip prefix dynamic 172.16.222.0/24
+  ip dns 0 8.8.8.8
+  ip dns 1 8.8.4.4
+  ip ifconfig 172.16.222.0/24
+  no shutdown
+ default-apn internet
+ no shutdown ggsn
--- a/doc/manuals/Makefile.am
+++ b/doc/manuals/Makefile.am
@@ -11,6 +11,12 @@ if BUILD_MANUALS
  include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.asciidoc.inc

  VTY_REFERENCE = osmoggsn-vty-reference.xml
+
+  BUILT_REFERENCE_XML = $(builddir)/vty/ggsn_vty_reference.xml
+  $(builddir)/vty/ggsn_vty_reference.xml: $(top_builddir)/ggsn/osmo-ggsn
+	mkdir -p $(builddir)/vty
+	$(top_builddir)/ggsn/osmo-ggsn --vty-ref-xml > $@
+
  include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.vty-reference.inc

  OSMO_REPOSITORY=osmo-ggsn
--- a/doc/manuals/chapters/configuration.adoc
+++ b/doc/manuals/chapters/configuration.adoc
@@ -101,7 +101,7 @@ OsmoGGSN(config-ggsn)# no shutdown ggsn <4>
 ----
 <1> Change into privileged mode
 <2> Enter the interactive configuration mode
-<3> Enter the config ndoe of the GGSN instance `ggsn0`
+<3> Enter the config node of the GGSN instance `ggsn0`
 <4> Take the GGSN instance out of shutdown


@@ -121,7 +121,7 @@ OsmoGGSN(config-ggsn)# shutdown ggsn <4>
 ----
 <1> Change into privileged mode
 <2> Enter the interactive configuration mode
-<3> Enter the config ndoe of the GGSN instance `ggsn0`
+<3> Enter the config node of the GGSN instance `ggsn0`
 <4> Shut down the GGSN instance


@@ -215,8 +215,8 @@ OsmoGGSN(config-ggsn-apn)# no shutdown <5>
 ----
 <1> Change into privileged mode
 <2> Enter the interactive configuration mode
-<3> Enter the config ndoe of the GGSN instance `ggsn0`
-<4> Enter the config ndoe of the APN `internet`
+<3> Enter the config node of the GGSN instance `ggsn0`
+<4> Enter the config node of the APN `internet`
 <5> Take the APN out of shutdown


@@ -237,8 +237,8 @@ OsmoGGSN(config-ggsn-apn)# shutdown <5>
 ----
 <1> Change into privileged mode
 <2> Enter the interactive configuration mode
-<3> Enter the config ndoe of the GGSN instance `ggsn0`
-<4> Enter the config ndoe of the APN `internet`
+<3> Enter the config node of the GGSN instance `ggsn0`
+<4> Enter the config node of the APN `internet`
 <5> Shut down the APN

 [[ggsn_no_root]]
@@ -302,7 +302,7 @@ Name=apn0 <1>
 Address=192.168.7.1/24 <2>
 IPMasquerade=yes <3>
 ----
-<1> The netowrk device name, which must match the one in the apn0.netdev unit file above
+<1> The network device name, which must match the one in the apn0.netdev unit file above
 <2> The local IP address configured on the device
 <3> Requesting systemd to configure IP masquerading for this interface.  Depending on your needs,
    You may not want this if you have proper end-to-end routing set up, and want to have transparent
--- a/doc/manuals/chapters/running.adoc
+++ b/doc/manuals/chapters/running.adoc
@@ -80,3 +80,52 @@ possible to pick differing ports on the same IP address), like:
 ggsn ggsn0
 gtp bind-ip 127.0.0.2
 ----
+
+=== GTP-U kernel module
+
+WARNING: As of writing, IPv6 support for the kernel module has not been
+         upstreamed yet (OS#1952).
+
+WARNING: As of writing, it is not possible to configure multiple APNs with
+         gtpu-mode kernel-gpt. This is a limitation in OsmoGGSN, not in the
+         kernel module (OS#6106).
+
+OsmoGGSN has support to use the Linux kernel GTP-U tunnel driver to accelerate
+the data/user plane while still implementing the control plane (GTP-C) in
+userspace in OsmoGGSN. The kernel module is included in Linux 4.7.0 and higher.
+Notably the Debian GNU/Linux distribution has it enabled by default.
+
+In order to use this feature, make sure that your Linux kernel was configured
+to support it (`CONFIG_GTP=m` or `=y`). Furthermore, `osmo-ggsn` must have been
+built with `./configure` argument `--enable-gtp-linux` (which requires libgtpnl
+to be installed).
+
+Load the kernel module with:
+
+----
+$ sudo modprobe gtp
+----
+
+Then start OsmoGGSN with a configuration file that uses `gtpu-mode kernel-gtp`.
+
+A full example configuration is in `osmo-ggsn-kernel-gtp.cfg`.
+
+----
+$ sudo osmo-ggsn -c /usr/share/doc/osmo-ggsn/examples/osmo-ggsn-kernel-gtp.cfg
+----
+
+.Example: APN with kernel-gtp
+----
+ggsn ggsn0
+ gtp state-dir /tmp
+ gtp bind-ip 127.0.0.2
+ apn internet
+  gtpu-mode kernel-gtp
+  tun-device tun4
+  type-support v4
+  ip prefix dynamic 172.16.222.0/24
+  ip dns 0 8.8.8.8
+  ip dns 1 8.8.4.4
+  ip ifconfig 172.16.222.0/24
+  no shutdown
+----
--- a/doc/manuals/osmoggsn-usermanual.adoc
+++ b/doc/manuals/osmoggsn-usermanual.adoc
@@ -20,6 +20,8 @@ include::{srcdir}/chapters/configuration.adoc[]

 include::./common/chapters/control_if.adoc[]

+include::./common/chapters/vty_cpu_sched.adoc[]
+
 include::./common/chapters/port_numbers.adoc[]

 include::./common/chapters/bibliography.adoc[]
--- a/doc/manuals/vty/ggsn_vty_reference.xml
+++ b/doc/manuals/vty/ggsn_vty_reference.xml
--- a/ggsn/Makefile.am
+++ b/ggsn/Makefile.am
@@ -2,7 +2,16 @@ bin_PROGRAMS = osmo-ggsn

 AM_LDFLAGS = @EXEC_LDFLAGS@

-AM_CFLAGS = -O2 -D_GNU_SOURCE -fno-builtin -Wall -DSBINDIR='"$(sbindir)"' -ggdb $(LIBOSMOCORE_CFLAGS) $(LIBOSMOCTRL_CFLAGS) $(LIBOSMOVTY_CFLAGS)
+AM_CFLAGS = \
+	    -D_GNU_SOURCE \
+	    -fno-builtin \
+	    -Wall \
+	    -DSBINDIR='"$(sbindir)"' \
+	    -I$(top_srcdir)/include \
+	    $(LIBOSMOCORE_CFLAGS) \
+	    $(LIBOSMOCTRL_CFLAGS) \
+	    $(LIBOSMOVTY_CFLAGS) \
+	    $(NULL)

 osmo_ggsn_LDADD = @EXEC_LDADD@ -lgtp -L../gtp ../lib/libmisc.a $(LIBOSMOCORE_LIBS) $(LIBOSMOCTRL_LIBS) $(LIBOSMOVTY_LIBS)

--- a/ggsn/ggsn.c
+++ b/ggsn/ggsn.c
@@ -46,17 +46,19 @@
 #include <osmocom/ctrl/control_if.h>
 #include <osmocom/gsm/apn.h>

+#include <osmocom/gtp/pdp.h>
+#include <osmocom/gtp/gtp.h>
+
 #include "../lib/tun.h"
 #include "../lib/ippool.h"
 #include "../lib/syserr.h"
 #include "../lib/in46_addr.h"
 #include "../lib/gtp-kernel.h"
 #include "../lib/util.h"
-#include "../gtp/pdp.h"
-#include "../gtp/gtp.h"
 #include "../lib/icmpv6.h"
 #include "pco.h"
 #include "ggsn.h"
+#include "../gtp/gtp_internal.h"

 static int ggsn_tun_fd_cb(struct osmo_fd *fd, unsigned int what);
 static int cb_tun_ind(struct tun_t *tun, void *pack, unsigned len);
@@ -193,8 +195,8 @@ int apn_start(struct apn_ctx *apn)
 		}
 		LOGPAPN(LOGL_INFO, apn, "Opened TUN device %s\n", apn->tun.tun->devname);

-		/* Register with libosmcoore */
-		osmo_fd_setup(&apn->tun.fd, apn->tun.tun->fd, BSC_FD_READ, ggsn_tun_fd_cb, apn, 0);
+		/* Register with libosmocore */
+		osmo_fd_setup(&apn->tun.fd, apn->tun.tun->fd, OSMO_FD_READ, ggsn_tun_fd_cb, apn, 0);
 		osmo_fd_register(&apn->tun.fd);

 		/* Set TUN library callback */
@@ -202,11 +204,6 @@ int apn_start(struct apn_ctx *apn)
 		break;
 	case APN_GTPU_MODE_KERNEL_GTP:
 		LOGPAPN(LOGL_INFO, apn, "Opening Kernel GTP device %s\n", apn->tun.cfg.dev_name);
-		if (apn->cfg.apn_type_mask & (APN_TYPE_IPv6|APN_TYPE_IPv4v6)) {
-			LOGPAPN(LOGL_ERROR, apn, "Kernel GTP currently supports only IPv4\n");
-			apn_stop(apn);
-			return -1;
-		}
 		if (gsn == NULL) {
 			/* skip bringing up the APN now if the GSN is not initialized yet.
 			 * This happens during initial load of the config file, as the
@@ -467,9 +464,13 @@ int create_context_ind(struct pdp_t *pdp)
 		return 0;
 	}

-	/* FIXME: we manually force all context requests to dynamic here! */
-	if (pdp->eua.l > 2)
-		pdp->eua.l = 2;
+	/* FIXME: implement context request for static IP addresses! */
+	if (pdp->eua.l > 2) {
+		LOGPPDP(LOGL_ERROR, pdp, "Static IP addresses not supported: %s\n",
+			osmo_hexdump(pdp->eua.v, pdp->eua.l));
+		gtp_create_context_resp(gsn, pdp, GTPCAUSE_NOT_SUPPORTED);
+		return 0;
+	}

 	memcpy(pdp->qos_neg0, pdp->qos_req0, sizeof(pdp->qos_req0));

@@ -532,10 +533,11 @@ int create_context_ind(struct pdp_t *pdp)

 	in46a_to_eua(addr, num_addr, &pdp->eua);

-	if (apn->cfg.gtpu_mode == APN_GTPU_MODE_KERNEL_GTP && apn_supports_ipv4(apn)) {
-		/* TODO: In IPv6, EUA doesn't contain the actual IP addr/prefix! */
+	if (apn->cfg.gtpu_mode == APN_GTPU_MODE_KERNEL_GTP) {
 		if (gtp_kernel_tunnel_add(pdp, apn->tun.cfg.dev_name) < 0) {
 			LOGPPDP(LOGL_ERROR, pdp, "Cannot add tunnel to kernel: %s\n", strerror(errno));
+			if (addrv6 && errno == EINVAL)
+				LOGPPDP(LOGL_ERROR, pdp, "Maybe your kernel does not support GTP-U with IPv6 yet?\n");
 			gtp_create_context_resp(gsn, pdp, GTPCAUSE_SYS_FAIL);
 			return 0;
 		}
@@ -589,7 +591,7 @@ static int cb_tun_ind(struct tun_t *tun, void *pack, unsigned len)
 	struct iphdr *iph = (struct iphdr *)pack;
 	struct ip6_hdr *ip6h = (struct ip6_hdr *)pack;
 	struct ippool_t *pool;
-	char straddr[INET6_ADDRSTRLEN];
+	char straddr[2][INET6_ADDRSTRLEN];
 	uint8_t pref_offset;

 	switch (iph->version) {
@@ -622,17 +624,41 @@ static int cb_tun_ind(struct tun_t *tun, void *pack, unsigned len)
 		return 0;

 	if (ippool_getip(pool, &ipm, &dst)) {
-		LOGTUN(LOGL_DEBUG, tun, "Received packet for APN(%s) with no PDP contex! (%s)\n",
-			apn->cfg.name,
-			iph->version == 4 ?
-			inet_ntop(AF_INET, &iph->saddr, straddr, sizeof(straddr)) :
-			inet_ntop(AF_INET6, &ip6h->ip6_src, straddr, sizeof(straddr)));
+		LOGTUN(LOGL_DEBUG, tun, "APN(%s) Rx DL data packet for IP address outside "
+		       "pool of managed addresses: %s <- %s\n",
+		       apn->cfg.name,
+		       iph->version == 4 ?
+		         inet_ntop(AF_INET, &iph->daddr, straddr[0], sizeof(straddr[0])) :
+		         inet_ntop(AF_INET6, &ip6h->ip6_dst, straddr[0], sizeof(straddr[0])),
+		       iph->version == 4 ?
+		         inet_ntop(AF_INET, &iph->saddr, straddr[1], sizeof(straddr[1])) :
+		         inet_ntop(AF_INET6, &ip6h->ip6_src, straddr[1], sizeof(straddr[1])));
 		return 0;
 	}
-	LOGTUN(LOGL_DEBUG, tun, "Received packet for APN(%s)\n", apn->cfg.name);

-	if (ipm->peer)		/* Check if a peer protocol is defined */
-		gtp_data_req(apn->ggsn->gsn, (struct pdp_t *)ipm->peer, pack, len);
+	if (ipm->peer)	{	/* Check if a peer protocol is defined */
+		struct pdp_t *pdp = (struct pdp_t *)ipm->peer;
+		LOGTUN(LOGL_DEBUG, tun, "APN(%s) Rx DL data packet for PDP(%s:%u): %s <- %s\n",
+		       apn->cfg.name,
+		       imsi_gtp2str(&(pdp)->imsi), (pdp)->nsapi,
+		       iph->version == 4 ?
+		         inet_ntop(AF_INET, &iph->daddr, straddr[0], sizeof(straddr[0])) :
+		         inet_ntop(AF_INET6, &ip6h->ip6_dst, straddr[0], sizeof(straddr[0])),
+		       iph->version == 4 ?
+		         inet_ntop(AF_INET, &iph->saddr, straddr[1], sizeof(straddr[1])) :
+		         inet_ntop(AF_INET6, &ip6h->ip6_src, straddr[1], sizeof(straddr[1])));
+		gtp_data_req(apn->ggsn->gsn, pdp, pack, len);
+	} else {
+		LOGTUN(LOGL_DEBUG, tun, "APN(%s) Rx DL data packet for IP address with no "
+		       "associated PDP Ctx: %s <- %s\n",
+		       apn->cfg.name,
+		       iph->version == 4 ?
+ 		         inet_ntop(AF_INET, &iph->daddr, straddr[0], sizeof(straddr[0])) :
+ 		         inet_ntop(AF_INET6, &ip6h->ip6_dst, straddr[0], sizeof(straddr[0])),
+ 		       iph->version == 4 ?
+ 		         inet_ntop(AF_INET, &iph->saddr, straddr[1], sizeof(straddr[1])) :
+ 		         inet_ntop(AF_INET6, &ip6h->ip6_src, straddr[1], sizeof(straddr[1])));
+	}
 	return 0;
 }

@@ -704,7 +730,7 @@ static int ggsn_tun_fd_cb(struct osmo_fd *fd, unsigned int what)
 {
 	struct apn_ctx *apn = fd->data;

-	OSMO_ASSERT(what & BSC_FD_READ);
+	OSMO_ASSERT(what & OSMO_FD_READ);

 	return tun_decaps(apn->tun.tun);
 }
@@ -715,7 +741,7 @@ static int ggsn_gtp_fd_cb(struct osmo_fd *fd, unsigned int what)
 	struct ggsn_ctx *ggsn = fd->data;
 	int rc;

-	OSMO_ASSERT(what & BSC_FD_READ);
+	OSMO_ASSERT(what & OSMO_FD_READ);

 	switch (fd->priv_nr) {
 	case 0:
@@ -809,15 +835,15 @@ int ggsn_start(struct ggsn_ctx *ggsn)
 		ggsn->gsn->gsnu = ggsn->cfg.gtpu_addr.v4;

 	/* Register File Descriptors */
-	osmo_fd_setup(&ggsn->gtp_fd0, ggsn->gsn->fd0, BSC_FD_READ, ggsn_gtp_fd_cb, ggsn, 0);
+	osmo_fd_setup(&ggsn->gtp_fd0, ggsn->gsn->fd0, OSMO_FD_READ, ggsn_gtp_fd_cb, ggsn, 0);
 	rc = osmo_fd_register(&ggsn->gtp_fd0);
 	OSMO_ASSERT(rc == 0);

-	osmo_fd_setup(&ggsn->gtp_fd1c, ggsn->gsn->fd1c, BSC_FD_READ, ggsn_gtp_fd_cb, ggsn, 1);
+	osmo_fd_setup(&ggsn->gtp_fd1c, ggsn->gsn->fd1c, OSMO_FD_READ, ggsn_gtp_fd_cb, ggsn, 1);
 	rc = osmo_fd_register(&ggsn->gtp_fd1c);
 	OSMO_ASSERT(rc == 0);

-	osmo_fd_setup(&ggsn->gtp_fd1u, ggsn->gsn->fd1u, BSC_FD_READ, ggsn_gtp_fd_cb, ggsn, 2);
+	osmo_fd_setup(&ggsn->gtp_fd1u, ggsn->gsn->fd1u, OSMO_FD_READ, ggsn_gtp_fd_cb, ggsn, 2);
 	rc = osmo_fd_register(&ggsn->gtp_fd1u);
 	OSMO_ASSERT(rc == 0);

--- a/ggsn/ggsn.h
+++ b/ggsn/ggsn.h
@@ -6,13 +6,14 @@
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/core/select.h>
 #include <osmocom/core/timer.h>
+#include <osmocom/core/tdef.h>
 #include <osmocom/ctrl/control_if.h>
+#include <osmocom/gtp/gtp.h>

 #include "../lib/tun.h"
 #include "../lib/ippool.h"
 #include "../lib/syserr.h"
 #include "../lib/in46_addr.h"
-#include "../gtp/gtp.h"

 #include "sgsn.h"

@@ -65,9 +66,9 @@ struct apn_ctx {
 		uint32_t apn_type_mask;
 		/* GTP-U via TUN device or in Linux kernel */
 		enum apn_gtpu_mode gtpu_mode;
-		/* administratively shut-down (true) or not (false) */
+		/* administratively shut down (true) or not (false) */
 		bool shutdown;
-		/* transmit G-PDU sequeence numbers (true) or not (false) */
+		/* transmit G-PDU sequence numbers (true) or not (false) */
 		bool tx_gpdu_seq;
 	} cfg;

@@ -127,7 +128,7 @@ struct ggsn_ctx {
 		char *state_dir;
 		/* Time between Echo requests on each SGSN */
 		unsigned int echo_interval;
-		/* administratively shut-down (true) or not (false) */
+		/* administratively shut down (true) or not (false) */
 		bool shutdown;
 	} cfg;

@@ -152,6 +153,7 @@ struct apn_ctx *ggsn_find_or_create_apn(struct ggsn_ctx *ggsn, const char *name)
 /* ggsn_main.c */
 extern struct ctrl_handle *g_ctrlh;
 extern void *tall_ggsn_ctx;
+extern struct osmo_tdef_group ggsn_tdef_group[];

 /* ggsn.c */
 extern int ggsn_start(struct ggsn_ctx *ggsn);
@@ -167,6 +169,3 @@ void ggsn_close_one_pdp(struct pdp_t *pdp);
 	LOGP(DGGSN, level, "GGSN(%s): " fmt, (ggsn)->cfg.name, ## args)

 #define LOGPPDP(level, pdp, fmt, args...) LOGPDPX(DGGSN, level, pdp, fmt, ## args)
-
-#define LOGTUN(level, tun, fmt, args...) \
-	LOGP(DTUN, level, "TUN(%s): " fmt, (tun)->devname, ## args)
--- a/ggsn/ggsn_main.c
+++ b/ggsn/ggsn_main.c
@@ -34,6 +34,7 @@
 #include <osmocom/core/stats.h>
 #include <osmocom/core/rate_ctr.h>
 #include <osmocom/core/timer.h>
+#include <osmocom/core/tdef.h>
 #include <osmocom/core/utils.h>
 #include <osmocom/ctrl/control_if.h>
 #include <osmocom/ctrl/control_cmd.h>
@@ -45,6 +46,7 @@
 #include <osmocom/vty/ports.h>
 #include <osmocom/vty/command.h>
 #include <osmocom/vty/misc.h>
+#include <osmocom/vty/cpu_sched_vty.h>

 #include "ggsn.h"

@@ -59,6 +61,11 @@ struct ul255_t apn;

 static char *config_file = "osmo-ggsn.cfg";

+struct osmo_tdef_group ggsn_tdef_group[] = {
+	{.name = "gtp", .tdefs = gtp_T_defs, .desc = "GTP (libgtp) timers" },
+	{ }
+};
+
 /* To exit gracefully. Used with GCC compilation flag -pg and gprof */
 static void signal_handler(int s)
 {
@@ -70,6 +77,17 @@ static void signal_handler(int s)
 		end = 1;
 		break;
 	case SIGABRT:
+		/* in case of abort, we want to obtain a talloc report and
+		 * then run default SIGABRT handler, who will generate coredump
+		 * and abort the process. abort() should do this for us after we
+		 * return, but program wouldn't exit if an external SIGABRT is
+		 * received.
+		 */
+		talloc_report(tall_vty_ctx, stderr);
+		talloc_report_full(tall_ggsn_ctx, stderr);
+		signal(SIGABRT, SIG_DFL);
+		raise(SIGABRT);
+		break;
 	case SIGUSR1:
 		talloc_report(tall_vty_ctx, stderr);
 		talloc_report_full(tall_ggsn_ctx, stderr);
@@ -95,17 +113,49 @@ static void print_help()
 		"  -c --config-file	filename The config file to use\n"
 		"  -V --version		Print the version of OsmoGGSN\n"
 		);
+
+	printf("\nVTY reference generation:\n");
+	printf("     --vty-ref-mode MODE        VTY reference generation mode (e.g. 'expert').\n");
+	printf("     --vty-ref-xml              Generate the VTY reference XML output and exit.\n");
+}
+
+static void handle_long_options(const char *prog_name, const int long_option)
+{
+	static int vty_ref_mode = VTY_REF_GEN_MODE_DEFAULT;
+
+	switch (long_option) {
+	case 1:
+		vty_ref_mode = get_string_value(vty_ref_gen_mode_names, optarg);
+		if (vty_ref_mode < 0) {
+			fprintf(stderr, "%s: Unknown VTY reference generation "
+				"mode '%s'\n", prog_name, optarg);
+			exit(2);
+		}
+		break;
+	case 2:
+		fprintf(stderr, "Generating the VTY reference in mode '%s' (%s)\n",
+			get_value_string(vty_ref_gen_mode_names, vty_ref_mode),
+			get_value_string(vty_ref_gen_mode_desc, vty_ref_mode));
+		vty_dump_xml_ref_mode(stdout, (enum vty_ref_gen_mode) vty_ref_mode);
+		exit(0);
+	default:
+		fprintf(stderr, "%s: error parsing cmdline options\n", prog_name);
+		exit(2);
+	}
 }

 static void handle_options(int argc, char **argv)
 {
 	while (1) {
 		int option_index = 0, c;
+		static int long_option = 0;
 		static struct option long_options[] = {
 			{ "help", 0, 0, 'h' },
 			{ "daemonize", 0, 0, 'D' },
 			{ "config-file", 1, 0, 'c' },
 			{ "version", 0, 0, 'V' },
+			{ "vty-ref-mode", 1, &long_option, 1 },
+			{ "vty-ref-xml", 0, &long_option, 2 },
 			{ 0, 0, 0, 0 }
 		};

@@ -114,6 +164,9 @@ static void handle_options(int argc, char **argv)
 			break;

 		switch (c) {
+		case 0:
+			handle_long_options(argv[0], long_option);
+			break;
 		case 'h':
 			print_usage();
 			print_help();
@@ -158,6 +211,7 @@ int main(int argc, char **argv)
 	osmo_stats_vty_add_cmds();
 	ggsn_vty_init();
 	ctrl_vty_init(tall_ggsn_ctx);
+	osmo_cpu_sched_vty_init(tall_ggsn_ctx);

 	handle_options(argc, argv);

@@ -169,12 +223,11 @@ int main(int argc, char **argv)
 		exit(2);
 	}

-	rc = telnet_init_dynif(tall_ggsn_ctx, NULL, vty_get_bind_addr(), OSMO_VTY_PORT_GGSN);
+	rc = telnet_init_default(tall_ggsn_ctx, NULL, OSMO_VTY_PORT_GGSN);
 	if (rc < 0)
 		exit(1);

-	g_ctrlh = ctrl_interface_setup_dynip(NULL, ctrl_vty_get_bind_addr(),
-					     OSMO_CTRL_PORT_GGSN, NULL);
+	g_ctrlh = ctrl_interface_setup(NULL, OSMO_CTRL_PORT_GGSN, NULL);
 	if (!g_ctrlh) {
 		LOGP(DGGSN, LOGL_ERROR, "Failed to create CTRL interface.\n");
 		exit(1);
--- a/ggsn/ggsn_vty.c
+++ b/ggsn/ggsn_vty.c
@@ -33,14 +33,16 @@
 #include <osmocom/vty/command.h>
 #include <osmocom/vty/vty.h>
 #include <osmocom/vty/misc.h>
+#include <osmocom/vty/tdef_vty.h>

-#include "../gtp/gtp.h"
-#include "../gtp/pdp.h"
+#include <osmocom/gtp/gtp.h>
+#include <osmocom/gtp/pdp.h>

 #include "../lib/util.h"

 #include "ggsn.h"
 #include "sgsn.h"
+#include "../gtp/gtp_internal.h"

 #define PREFIX_STR	"Prefix (Network/Netmask)\n"
 #define IFCONFIG_STR	"GGSN-based interface configuration\n"
@@ -298,7 +300,7 @@ DEFUN(cfg_ggsn_no_default_apn, cfg_ggsn_no_default_apn_cmd,

 DEFUN(cfg_ggsn_shutdown, cfg_ggsn_shutdown_cmd,
 	"shutdown ggsn",
-	"Put the GGSN in administrative shut-down\n" GGSN_STR)
+	"Put the GGSN in administrative shutdown\n" GGSN_STR)
 {
 	struct ggsn_ctx *ggsn = (struct ggsn_ctx *) vty->index;

@@ -315,7 +317,7 @@ DEFUN(cfg_ggsn_shutdown, cfg_ggsn_shutdown_cmd,

 DEFUN(cfg_ggsn_no_shutdown, cfg_ggsn_no_shutdown_cmd,
 	"no shutdown ggsn",
-	NO_STR GGSN_STR "Remove the GGSN from administrative shut-down\n")
+	NO_STR GGSN_STR "Remove the GGSN from administrative shutdown\n")
 {
 	struct ggsn_ctx *ggsn = (struct ggsn_ctx *) vty->index;

@@ -343,7 +345,7 @@ static void show_one_sgsn(struct vty *vty, const struct sgsn_peer *sgsn, const c

 DEFUN(cfg_ggsn_show_sgsn, cfg_ggsn_show_sgsn_cmd,
 	"show sgsn",
-	NO_STR GGSN_STR "Remove the GGSN from administrative shut-down\n")
+	NO_STR GGSN_STR "Remove the GGSN from administrative shutdown\n")
 {
 	struct ggsn_ctx *ggsn = (struct ggsn_ctx *) vty->index;
 	struct sgsn_peer *sgsn;
@@ -389,10 +391,9 @@ DEFUN(cfg_ggsn_no_echo_interval, cfg_ggsn_no_echo_interval_cmd,
 	NO_STR "Send an echo request to this static GGSN every interval.\n")
 {
 	struct ggsn_ctx *ggsn = (struct ggsn_ctx *) vty->index;
-	int prev_interval = ggsn->cfg.echo_interval;
 	struct sgsn_peer *sgsn;

-	if (prev_interval == ggsn->cfg.echo_interval)
+	if (ggsn->cfg.echo_interval == 0)
 		return CMD_SUCCESS;

 	ggsn->cfg.echo_interval = 0;
@@ -533,9 +534,11 @@ DEFUN(cfg_apn_ip_prefix, cfg_apn_ip_prefix_cmd,
 	struct in46_prefix *pfx;

 	/* first update our parsed prefix */
-	if (!strcmp(argv[0], "static"))
+	if (!strcmp(argv[0], "static")) {
 		pfx = &apn->v4.cfg.static_prefix;
-	else
+		vty_out(vty, "%% static IP addresses currently not yet supported%s", VTY_NEWLINE);
+		return CMD_WARNING;
+	} else
 		pfx = &apn->v4.cfg.dynamic_prefix;
 	str2prefix(pfx, argv[1]);

@@ -567,9 +570,11 @@ DEFUN(cfg_apn_ipv6_prefix, cfg_apn_ipv6_prefix_cmd,
 	struct apn_ctx *apn = (struct apn_ctx *) vty->index;
 	struct in46_prefix *pfx;

-	if (!strcmp(argv[0], "static"))
+	if (!strcmp(argv[0], "static")) {
 		pfx = &apn->v6.cfg.static_prefix;
-	else
+		vty_out(vty, "%% static IP addresses currently not yet supported%s", VTY_NEWLINE);
+		return CMD_WARNING;
+	} else
 		pfx = &apn->v6.cfg.dynamic_prefix;
 	str2prefix(pfx, argv[1]);
 	return CMD_SUCCESS;
@@ -677,7 +682,7 @@ DEFUN(cfg_apn_no_gpdu_seq, cfg_apn_no_gpdu_seq_cmd,

 DEFUN(cfg_apn_shutdown, cfg_apn_shutdown_cmd,
 	"shutdown",
-	"Put the APN in administrative shut-down\n")
+	"Put the APN in administrative shutdown\n")
 {
 	struct apn_ctx *apn = (struct apn_ctx *) vty->index;

@@ -694,11 +699,15 @@ DEFUN(cfg_apn_shutdown, cfg_apn_shutdown_cmd,

 DEFUN(cfg_apn_no_shutdown, cfg_apn_no_shutdown_cmd,
 	"no shutdown",
-	NO_STR "Remove the APN from administrative shut-down\n")
+	NO_STR "Remove the APN from administrative shutdown\n")
 {
 	struct apn_ctx *apn = (struct apn_ctx *) vty->index;

 	if (apn->cfg.shutdown) {
+		if (!apn->tun.cfg.dev_name) {
+			vty_out(vty, "%% Failed to start APN, tun-device is not configured%s", VTY_NEWLINE);
+			return CMD_WARNING;
+		}
 		if (apn_start(apn) < 0) {
 			vty_out(vty, "%% Failed to start APN, check log for details%s", VTY_NEWLINE);
 			return CMD_WARNING;
@@ -788,6 +797,7 @@ static int config_write_ggsn(struct vty *vty)
 			vty_out(vty, " gtp control-ip %s%s", in46a_ntoa(&ggsn->cfg.gtpc_addr), VTY_NEWLINE);
 		if (ggsn->cfg.gtpu_addr.v4.s_addr)
 			vty_out(vty, " gtp user-ip %s%s", in46a_ntoa(&ggsn->cfg.gtpu_addr), VTY_NEWLINE);
+		osmo_tdef_vty_groups_write(vty, " ");
 		llist_for_each_entry(apn, &ggsn->apn_list, list)
 			config_write_apn(vty, apn);
 		if (ggsn->cfg.default_apn)
@@ -805,10 +815,7 @@ static const char *print_gsnaddr(const struct ul16_t *in)
 {
 	struct in46_addr in46;

-	in46.len = in->l;
-	OSMO_ASSERT(in->l <= sizeof(in46.v6));
-	memcpy(&in46.v6, in->v, in->l);
-
+	in46a_from_gsna(in, &in46);
 	return in46a_ntoa(&in46);
 }

@@ -894,11 +901,16 @@ DEFUN(show_pdpctx_imsi, show_pdpctx_imsi_cmd,
 		return CMD_WARNING;
 	}

-	imsi = strtoull(argv[1], NULL, 10);
+	if (strlen(argv[1]) < 6 || strlen(argv[1]) > 15) {
+		vty_out(vty, "%% Invalid IMSI '%s'%s", argv[1], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	imsi = gtp_imsi_str2gtp(argv[1]);

 	if (argc > 2) {
 		nsapi = atoi(argv[2]);
-		if (gtp_pdp_getimsi(ggsn->gsn, &pdp, imsi, nsapi)) {
+		if (!gtp_pdp_getimsi(ggsn->gsn, &pdp, imsi, nsapi)) {
 			show_one_pdp(vty, pdp);
 			num_found++;
 		}
@@ -1101,6 +1113,8 @@ int ggsn_vty_init(void)
 	install_element(GGSN_NODE, &cfg_ggsn_echo_interval_cmd);
 	install_element(GGSN_NODE, &cfg_ggsn_no_echo_interval_cmd);

+	osmo_tdef_vty_groups_init(GGSN_NODE, ggsn_tdef_group);
+
 	install_node(&apn_node, NULL);
 	install_element(APN_NODE, &cfg_description_cmd);
 	install_element(APN_NODE, &cfg_no_description_cmd);
--- a/ggsn/pco.c
+++ b/ggsn/pco.c
@@ -110,6 +110,7 @@ ret_broken:
 		osmo_hexdump_nospc((const uint8_t *)pco_in, pco_in->length));
 }

+/* Handle IP Control Protocol, RFC 1332, extensions in RFC 1877 */
 static void process_pco_element_ipcp(const struct pco_element *pco_elem, struct msgb *resp,
 				     const struct apn_ctx *apn, struct pdp_t *pdp)
 {
--- a/ggsn/pco.h
+++ b/ggsn/pco.h
@@ -2,9 +2,9 @@

 #include <stdint.h>

-#include "../gtp/pdp.h"
+#include <osmocom/gtp/pdp.h>

-/* 3GPP TS 24.008 10.6.5.3 */
+/* 3GPP TS 24.008 10.5.6.3 */
 enum pco_protocols {
 	PCO_P_LCP		= 0xC021,
 	PCO_P_PAP		= 0xC023,
@@ -42,12 +42,11 @@ struct pco_element {
 	uint8_t data[0];
 } __attribute__((packed));

-
-/* RFC 1332 */
+/* RFC 1332 IP Control Protocol options, extensions in RFC 1877 */
 enum ipcp_options {
-	IPCP_OPT_IPADDR = 3,
-	IPCP_OPT_PRIMARY_DNS = 129,
-	IPCP_OPT_SECONDARY_DNS = 131,
+	IPCP_OPT_IPADDR = 3, /* RFC 1332 3.3 */
+	IPCP_OPT_PRIMARY_DNS = 129, /* RFC 1877 1.1 */
+	IPCP_OPT_SECONDARY_DNS = 131,  /* RFC 1877 1.2 */
 };

 struct ipcp_option_hdr {
--- a/ggsn/sgsn.c
+++ b/ggsn/sgsn.c
@@ -1,6 +1,6 @@
 #include "sgsn.h"
 #include "ggsn.h"
-
+#include "../gtp/gtp_internal.h"

 static bool sgsn_peer_attempt_free(struct sgsn_peer *sgsn)
 {
@@ -116,6 +116,7 @@ static unsigned int sgsn_peer_drop_all_pdp_except(struct sgsn_peer *sgsn, struct
 {
 	unsigned int num = 0;
 	char buf[INET_ADDRSTRLEN];
+	unsigned int count = llist_count(&sgsn->pdp_list);

 	inet_ntop(AF_INET, &sgsn->addr, buf, sizeof(buf));

@@ -125,10 +126,17 @@ static unsigned int sgsn_peer_drop_all_pdp_except(struct sgsn_peer *sgsn, struct
 			continue;
 		ggsn_close_one_pdp(pdp->lib);
 		num++;
+		if (num == count) {
+			/* Note: if except is NULL, all pdp contexts are freed and sgsn
+			 * is most probably already freed at this point.
+			 * As a result, last access to sgsn->pdp_list before exiting
+			 * loop would access already freed memory. Avoid it by exiting
+			 * the loop without the last check, and make sure sgsn is not
+			 * accessed after this loop. */
+			 break;
+		}
 	}

-	/* Note: if except is NULL, all pdp contexts are freed and sgsn is
-	   already freed at this point */
 	LOGP(DGGSN, LOGL_INFO, "SGSN(%s) Dropped %u PDP contexts\n", buf, num);

 	return num;
--- a/ggsn/sgsn.h
+++ b/ggsn/sgsn.h
@@ -8,7 +8,7 @@
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/core/timer.h>

-#include "../gtp/pdp.h"
+#include <osmocom/gtp/pdp.h>

 struct ggsn_ctx;
 struct pdp_priv_t;
--- a/gtp/Makefile.am
+++ b/gtp/Makefile.am
@@ -2,14 +2,30 @@
 # Please read chapter "Library interface versions" of the libtool documentation
 # before making any modifications: https://www.gnu.org/software/libtool/manual/html_node/Versioning.html
 # If major=current-age is increased, remember to update the dh_strip line in debian/rules!
-LIBVERSION=6:0:0
+LIBVERSION=9:1:3

 lib_LTLIBRARIES = libgtp.la

-include_HEADERS = gtp.h pdp.h gtpie.h
+AM_CFLAGS = \
+	    -fno-builtin \
+	    -Wall \
+	    -DSBINDIR='"$(sbindir)"' \
+	    -I$(top_srcdir)/include \
+	    $(LIBOSMOCORE_CFLAGS) \
+	    $(NULL)

-AM_CFLAGS = -O2 -fno-builtin -Wall -DSBINDIR='"$(sbindir)"' -ggdb $(LIBOSMOCORE_CFLAGS)
+libgtp_la_SOURCES = \
+		    gsn.c \
+		    gsn_internal.h \
+		    gtp.c \
+		    gtp_internal.h \
+		    gtpie.c \
+		    lookupa.c \
+		    lookupa.h \
+		    pdp.c \
+		    queue.c \
+		    queue.h \
+		    $(NULL)

-libgtp_la_SOURCES = gtp.c gtp.h gtpie.c gtpie.h pdp.c pdp.h lookupa.c lookupa.h queue.c queue.h
 libgtp_la_LDFLAGS = -version-info $(LIBVERSION) -no-undefined
 libgtp_la_LIBADD = $(LIBOSMOCORE_LIBS)
--- a/gtp/gsn.c
+++ b/gtp/gsn.c
@@ -0,0 +1,578 @@
+/*
+ *  OsmoGGSN - Gateway GPRS Support Node
+ *  Copyright (C) 2002, 2003, 2004 Mondru AB.
+ *  Copyright (C) 2010-2011, 2016-2017 Harald Welte <laforge@gnumonks.org>
+ *  Copyright (C) 2015-2017 sysmocom - s.f.m.c. GmbH
+ *
+ *  The contents of this file may be used under the terms of the GNU
+ *  General Public License Version 2, provided that the above copyright
+ *  notice and this permission notice is included in all copies or
+ *  substantial portions of the software.
+ *
+ */
+
+/*
+ * gtp.c: Contains all GTP functionality. Should be able to handle multiple
+ * tunnels in the same program.
+ *
+ * TODO:
+ *  - Do we need to handle fragmentation?
+ */
+
+#ifdef __linux__
+#define _GNU_SOURCE 1
+#endif
+
+#include <osmocom/core/logging.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/stats.h>
+#include <osmocom/core/rate_ctr.h>
+
+#if defined(__FreeBSD__)
+#include <sys/endian.h>
+#endif
+
+#include "../config.h"
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+
+#include <arpa/inet.h>
+
+/* #include <stdint.h>  ISO C99 types */
+
+#include <osmocom/gtp/pdp.h>
+#include <osmocom/gtp/gtp.h>
+#include <osmocom/gtp/gtpie.h>
+
+#include "queue.h"
+#include "gsn_internal.h"
+
+/* Error reporting functions */
+
+#define LOGP_WITH_ADDR(ss, level, addr, fmt, args...)                    \
+		LOGP(ss, level, "addr(%s:%d) " fmt,                      \
+		     inet_ntoa((addr).sin_addr), htons((addr).sin_port), \
+		     ##args)
+
+static const struct rate_ctr_desc gsn_ctr_description[] = {
+	[GSN_CTR_ERR_SOCKET] = { "err:socket", "Socket error" },
+	[GSN_CTR_ERR_READFROM] = { "err:readfrom", "readfrom() errors" },
+	[GSN_CTR_ERR_SENDTO] = { "err:sendto", "sendto() errors" },
+	[GSN_CTR_ERR_QUEUEFULL] = { "err:queuefull", "Failed to queue message because queue is full" },
+	[GSN_CTR_ERR_SEQ] = { "err:seq", "Sequence number out of range" },
+	[GSN_CTR_ERR_ADDRESS] = { "err:address", "GSN address conversion failed" },
+	[GSN_CTR_ERR_UNKNOWN_PDP] = { "err:unknown_pdp", "Failed looking up PDP context" },
+	[GSN_CTR_ERR_UNEXPECTED_CAUSE] = { "err:unexpected_cause", "Unexpected cause value received" },
+	[GSN_CTR_ERR_OUT_OF_PDP] = { "err:out_of_pdp", "Out of storage for PDP contexts" },
+	[GSN_CTR_PKT_EMPTY] = { "pkt:empty", "Empty packet received" },
+	[GSN_CTR_PKT_UNSUP] = { "pkt:unsupported", "Unsupported GTP version received" },
+	[GSN_CTR_PKT_TOOSHORT] = { "pkt:too_short", "Packet too short received" },
+	[GSN_CTR_PKT_UNKNOWN] = { "pkt:unknown", "Unknown packet type received" },
+	[GSN_CTR_PKT_UNEXPECT] = { "pkt:unexpected", "Unexpected packet type received" },
+	[GSN_CTR_PKT_DUPLICATE] = { "pkt:duplicate", "Duplicate or unsolicited packet received" },
+	[GSN_CTR_PKT_MISSING] = { "pkt:missing", "Missing IE in packet received" },
+	[GSN_CTR_PKT_INCORRECT] = { "pkt:incorrect", "Incorrect IE in packet received" },
+	[GSN_CTR_PKT_INVALID] = { "pkt:invalid", "Invalid format in packet received" },
+};
+
+static const struct rate_ctr_group_desc gsn_ctrg_desc = {
+	"gsn",
+	"GSN Statistics",
+	OSMO_STATS_CLASS_PEER,
+	ARRAY_SIZE(gsn_ctr_description),
+	gsn_ctr_description,
+};
+static unsigned int gsn_ctr_next_idx = 0;
+
+/* Global timer definitions for GTP operation, provided for convenience. To make these user configurable, it is convenient to add
+ * gtp_gsn_tdefs as one of your program's osmo_tdef_group entries and call osmo_tdef_vty_init(). */
+struct osmo_tdef gtp_T_defs[] = {
+	{ .T = GTP_GSN_TIMER_T3_RESPONSE, .default_val = 5, .unit = OSMO_TDEF_S,
+	  .desc = "Timer T3-RESPONSE holds the maximum wait time for a response of a request message"
+	},
+	{ .T = GTP_GSN_TIMER_N3_REQUESTS, .default_val = 3, .unit = OSMO_TDEF_CUSTOM,
+	  .desc = "Counter N3-REQUESTS holds the maximum number of attempts made by GTP to send a request message"
+	},
+	{ .T = GTP_GSN_TIMER_T3_HOLD_RESPONSE, .default_val = 5 * 3 /* (GTP_GSN_TIMER_T3_RESPONSE * GTP_GSN_TIMER_N3_REQUESTS) */, .unit = OSMO_TDEF_S,
+	  .desc = "Time a GTP respoonse message is kept cached to re-transmit it when a duplicate request is received. Value is generally equal to (T3-RESPONSE * N3-REQUESTS) set at the peer"
+	},
+	{}
+};
+
+
+/* API Functions */
+
+/* Deprecated, use gtp_pdp_newpdp() instead */
+int gtp_newpdp(struct gsn_t *gsn, struct pdp_t **pdp,
+	       uint64_t imsi, uint8_t nsapi)
+{
+	int rc;
+	rc = gtp_pdp_newpdp(gsn, pdp, imsi, nsapi, NULL);
+	return rc;
+}
+
+int gtp_freepdp(struct gsn_t *gsn, struct pdp_t *pdp)
+{
+	if (gsn->cb_delete_context)
+		gsn->cb_delete_context(pdp);
+	return pdp_freepdp(pdp);
+}
+
+/* Free pdp and all its secondary PDP contexts. Must be called on the primary PDP context. */
+int gtp_freepdp_teardown(struct gsn_t *gsn, struct pdp_t *pdp)
+{
+	int n;
+	struct pdp_t *secondary_pdp;
+	OSMO_ASSERT(!pdp->secondary);
+
+	for (n = 0; n < PDP_MAXNSAPI; n++) {
+		if (pdp->secondary_tei[n]) {
+			if (gtp_pdp_getgtp1(gsn, &secondary_pdp,
+					     pdp->secondary_tei[n])) {
+				LOGP(DLGTP, LOGL_ERROR,
+					"Unknown secondary PDP context\n");
+				continue;
+			}
+			if (pdp != secondary_pdp) {
+				gtp_freepdp(gsn, secondary_pdp);
+			}
+		}
+	}
+
+	return gtp_freepdp(gsn, pdp);
+}
+
+/* gtp_gpdu */
+
+extern int gtp_fd(struct gsn_t *gsn)
+{
+	return gsn->fd0;
+}
+
+int gtp_set_cb_unsup_ind(struct gsn_t *gsn,
+			 int (*cb) (struct sockaddr_in * peer))
+{
+	gsn->cb_unsup_ind = cb;
+	return 0;
+}
+
+int gtp_set_cb_extheader_ind(struct gsn_t *gsn,
+			     int (*cb) (struct sockaddr_in * peer))
+{
+	gsn->cb_extheader_ind = cb;
+	return 0;
+}
+
+int gtp_set_cb_ran_info_relay_ind(struct gsn_t *gsn,
+			     int (*cb) (struct sockaddr_in * peer, union gtpie_member **ie))
+{
+	gsn->cb_ran_info_relay_ind = cb;
+	return 0;
+}
+
+/* API: Initialise delete context callback */
+/* Called whenever a pdp context is deleted for any reason */
+int gtp_set_cb_delete_context(struct gsn_t *gsn, int (*cb) (struct pdp_t * pdp))
+{
+	gsn->cb_delete_context = cb;
+	return 0;
+}
+
+int gtp_set_cb_conf(struct gsn_t *gsn,
+		    int (*cb) (int type, int cause,
+			       struct pdp_t * pdp, void *cbp))
+{
+	gsn->cb_conf = cb;
+	return 0;
+}
+
+int gtp_set_cb_recovery(struct gsn_t *gsn,
+			int (*cb) (struct sockaddr_in * peer, uint8_t recovery))
+{
+	gsn->cb_recovery = cb;
+	return 0;
+}
+
+/* cb_recovery()
+ * pdp may be NULL if Recovery IE was received from a message independent
+ * of any PDP ctx (such as Echo Response), or because pdp ctx is unknown to the
+ * local setup. In case pdp is known, caller may want to keep that pdp alive to
+ * handle subsequent msg cb as this specific pdp ctx is still valid according to
+ * specs.
+ */
+int gtp_set_cb_recovery2(struct gsn_t *gsn,
+			int (*cb_recovery2) (struct sockaddr_in * peer, struct pdp_t * pdp, uint8_t recovery))
+{
+	gsn->cb_recovery2 = cb_recovery2;
+	return 0;
+}
+
+/* cb_recovery()
+ * pdp may be NULL if Recovery IE was received from a message independent
+ * of any PDP ctx (such as Echo Response), or because pdp ctx is unknown to the
+ * local setup. In case pdp is known, caller may want to keep that pdp alive to
+ * handle subsequent msg cb as this specific pdp ctx is still valid according to
+ * specs.
+ */
+int gtp_set_cb_recovery3(struct gsn_t *gsn,
+			 int (*cb_recovery3) (struct gsn_t *gsn, struct sockaddr_in *peer,
+					      struct pdp_t *pdp, uint8_t recovery))
+{
+	gsn->cb_recovery3 = cb_recovery3;
+	return 0;
+}
+
+int gtp_set_cb_data_ind(struct gsn_t *gsn,
+			       int (*cb_data_ind) (struct pdp_t * pdp,
+						   void *pack, unsigned len))
+{
+	gsn->cb_data_ind = cb_data_ind;
+	return 0;
+}
+
+static int queue_timer_retrans(struct gsn_t *gsn)
+{
+	/* Retransmit any outstanding packets */
+	/* Remove from queue if maxretrans exceeded */
+	time_t now;
+	struct qmsg_t *qmsg;
+	unsigned int t3_response, n3_requests;
+
+	now = time(NULL);
+	t3_response = osmo_tdef_get(gsn->tdef, GTP_GSN_TIMER_T3_RESPONSE, OSMO_TDEF_S, -1);
+	n3_requests = osmo_tdef_get(gsn->tdef, GTP_GSN_TIMER_N3_REQUESTS, OSMO_TDEF_CUSTOM, -1);
+
+	/* get first element in queue, as long as the timeout of that
+	 * element has expired */
+	while ((!queue_getfirst(gsn->queue_req, &qmsg)) &&
+	       (qmsg->timeout <= now)) {
+		if (qmsg->retrans > n3_requests) {	/* Too many retrans */
+			LOGP(DLGTP, LOGL_NOTICE, "Retransmit req queue timeout of seq %" PRIu16 "\n",
+			     qmsg->seq);
+			if (gsn->cb_conf)
+				gsn->cb_conf(qmsg->type, EOF, NULL, qmsg->cbp);
+			queue_freemsg(gsn->queue_req, qmsg);
+		} else {
+			LOGP(DLGTP, LOGL_INFO, "Retransmit (%d) of seq %" PRIu16 "\n",
+			     qmsg->retrans, qmsg->seq);
+			if (sendto(qmsg->fd, &qmsg->p, qmsg->l, 0,
+				   (struct sockaddr *)&qmsg->peer,
+				   sizeof(struct sockaddr_in)) < 0) {
+				rate_ctr_inc2(gsn->ctrg, GSN_CTR_ERR_SENDTO);
+				LOGP(DLGTP, LOGL_ERROR,
+					"Sendto(fd0=%d, msg=%lx, len=%d) failed: Error = %s\n",
+					gsn->fd0, (unsigned long)&qmsg->p,
+					qmsg->l, strerror(errno));
+			}
+			queue_back(gsn->queue_req, qmsg);
+			qmsg->timeout = now + t3_response;
+			qmsg->retrans++;
+		}
+	}
+
+	/* Also clean up reply timeouts */
+	while ((!queue_getfirst(gsn->queue_resp, &qmsg)) &&
+	       (qmsg->timeout < now)) {
+		LOGP(DLGTP, LOGL_DEBUG, "Retransmit resp queue seq %"
+		     PRIu16 " expired, removing from queue\n", qmsg->seq);
+		queue_freemsg(gsn->queue_resp, qmsg);
+	}
+
+	return 0;
+}
+
+static int queue_timer_retranstimeout(struct gsn_t *gsn, struct timeval *timeout)
+{
+	time_t now, later, diff;
+	struct qmsg_t *qmsg;
+	timeout->tv_usec = 0;
+
+	if (queue_getfirst(gsn->queue_req, &qmsg)) {
+		timeout->tv_sec = 10;
+	} else {
+		now = time(NULL);
+		later = qmsg->timeout;
+		timeout->tv_sec = later - now;
+		if (timeout->tv_sec < 0)
+			timeout->tv_sec = 0;	/* No negative allowed */
+		if (timeout->tv_sec > 10)
+			timeout->tv_sec = 10;	/* Max sleep for 10 sec */
+	}
+
+	if (queue_getfirst(gsn->queue_resp, &qmsg)) {
+		/* already set by queue_req, do nothing */
+	} else { /* trigger faster if earlier timeout exists in queue_resp */
+		now = time(NULL);
+		later = qmsg->timeout;
+		diff = later - now;
+		if (diff < 0)
+			diff = 0;
+		if (diff < timeout->tv_sec)
+			timeout->tv_sec = diff;
+	}
+
+	return 0;
+}
+
+void gtp_queue_timer_start(struct gsn_t *gsn)
+{
+	struct timeval next;
+
+	/* Retrieve next retransmission as timeval */
+	queue_timer_retranstimeout(gsn, &next);
+
+	/* re-schedule the timer */
+	osmo_timer_schedule(&gsn->queue_timer, next.tv_sec, next.tv_usec/1000);
+}
+
+/* timer callback for libgtp retransmission and ping */
+static void queue_timer_cb(void *data)
+{
+	struct gsn_t *gsn = data;
+
+	/* do all the retransmissions as needed */
+	queue_timer_retrans(gsn);
+
+	gtp_queue_timer_start(gsn);
+}
+
+
+/**
+ * @brief clear the request and response queue. Useful for debugging to reset "some" state.
+ * @param gsn The GGSN instance
+ */
+void gtp_clear_queues(struct gsn_t *gsn)
+{
+	struct qmsg_t *qmsg;
+
+	LOGP(DLGTP, LOGL_INFO, "Clearing req & resp retransmit queues\n");
+	while (!queue_getfirst(gsn->queue_req, &qmsg)) {
+		queue_freemsg(gsn->queue_req, qmsg);
+	}
+
+	while (!queue_getfirst(gsn->queue_resp, &qmsg)) {
+		queue_freemsg(gsn->queue_resp, qmsg);
+	}
+}
+
+/* Perform restoration and recovery error handling as described in 29.060 */
+static void log_restart(struct gsn_t *gsn)
+{
+	FILE *f;
+	int i, rc;
+	int counter = 0;
+	char *filename;
+
+	filename = talloc_asprintf(NULL, "%s/%s", gsn->statedir, RESTART_FILE);
+	OSMO_ASSERT(filename);
+
+	/* We try to open file. On failure we will later try to create file */
+	if (!(f = fopen(filename, "r"))) {
+		LOGP(DLGTP, LOGL_NOTICE,
+			"State information file (%s) not found. Creating new file.\n",
+			filename);
+	} else {
+		rc = fscanf(f, "%d", &counter);
+		if (rc != 1) {
+			LOGP(DLGTP, LOGL_ERROR,
+				"fscanf failed to read counter value\n");
+			goto close_file;
+		}
+		if (fclose(f)) {
+			LOGP(DLGTP, LOGL_ERROR,
+				"fclose failed: Error = %s\n", strerror(errno));
+		}
+	}
+
+	gsn->restart_counter = (unsigned char)counter;
+	gsn->restart_counter++;
+
+	/* Keep the umask closely wrapped around our fopen() call in case the
+	 * log outputs cause file creation. */
+	i = umask(022);
+	f = fopen(filename, "w");
+	umask(i);
+	if (!f) {
+		LOGP(DLGTP, LOGL_ERROR,
+			"fopen(path=%s, mode=%s) failed: Error = %s\n", filename,
+			"w", strerror(errno));
+		goto free_filename;
+	}
+
+	fprintf(f, "%d\n", gsn->restart_counter);
+close_file:
+	if (fclose(f))
+		LOGP(DLGTP, LOGL_ERROR,
+			"fclose failed: Error = %s\n", strerror(errno));
+free_filename:
+	talloc_free(filename);
+}
+
+static int create_and_bind_socket(const char *name, struct gsn_t *gsn, int *fd, int domain,
+				  const struct in_addr *listen, int port)
+{
+	struct sockaddr_in addr;
+	int type = SOCK_DGRAM;
+	int protocol = 0;
+
+	*fd = socket(domain, type, protocol);
+
+	if (*fd < 0) {
+		rate_ctr_inc2(gsn->ctrg, GSN_CTR_ERR_SOCKET);
+		LOGP(DLGTP, LOGL_ERROR,
+		     "%s socket(domain=%d, type=%d, protocol=%d) failed: Error = %s\n",
+		     name, domain, type, protocol, strerror(errno));
+		return -errno;
+	}
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sin_family = domain;
+	addr.sin_addr = *listen;
+	addr.sin_port = htons(port);
+#if defined(__FreeBSD__) || defined(__APPLE__)
+	addr.sin_len = sizeof(addr);
+#endif
+
+	if (bind(*fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+		rate_ctr_inc2(gsn->ctrg, GSN_CTR_ERR_SOCKET);
+		LOGP_WITH_ADDR(DLGTP, LOGL_ERROR, addr,
+			       "%s bind(fd=%d) failed: Error = %s\n",
+			       name, *fd, strerror(errno));
+		return -errno;
+	}
+
+	return 0;
+}
+
+int gtp_new(struct gsn_t **gsn, char *statedir, struct in_addr *listen,
+	    int mode)
+{
+	LOGP(DLGTP, LOGL_NOTICE, "GTP: gtp_newgsn() started at %s\n", inet_ntoa(*listen));
+
+	*gsn = calloc(sizeof(struct gsn_t), 1);	/* TODO */
+
+	(*gsn)->statedir = statedir;
+	log_restart(*gsn);
+
+	/* Initialise sequence number */
+	(*gsn)->seq_next = (*gsn)->restart_counter * 1024;
+
+	/* Initialize timers: */
+	(*gsn)->tdef = gtp_T_defs;
+	/* Small hack to properly reset tdef for old clients not using the tdef_group: */
+	OSMO_ASSERT(gtp_T_defs[0].default_val != 0);
+	if (gtp_T_defs[0].val == 0)
+		osmo_tdefs_reset((*gsn)->tdef);
+
+
+	/* Initialise request retransmit queue */
+	queue_new(&(*gsn)->queue_req);
+	queue_new(&(*gsn)->queue_resp);
+
+	/* Initialise pdp table */
+	pdp_init(*gsn);
+
+	/* Initialize internal queue timer */
+	osmo_timer_setup(&(*gsn)->queue_timer, queue_timer_cb, *gsn);
+
+	/* Initialize counter group: */
+	(*gsn)->ctrg = rate_ctr_group_alloc(NULL, &gsn_ctrg_desc, gsn_ctr_next_idx++);
+
+	/* Initialise call back functions */
+	(*gsn)->cb_create_context_ind = 0;
+	(*gsn)->cb_delete_context = 0;
+	(*gsn)->cb_unsup_ind = 0;
+	(*gsn)->cb_conf = 0;
+	(*gsn)->cb_data_ind = 0;
+
+	/* Store function parameters */
+	/* Same IP for user traffic and signalling */
+	(*gsn)->gsnc = *listen;
+	(*gsn)->gsnu = *listen;
+	(*gsn)->mode = mode;
+
+	(*gsn)->fd0 = -1;
+	(*gsn)->fd1c = -1;
+	(*gsn)->fd1u = -1;
+
+	/* Create GTP version 0 socket */
+	if (create_and_bind_socket("GTPv0", *gsn, &(*gsn)->fd0, AF_INET, listen, GTP0_PORT) < 0)
+		goto error;
+
+	/* Create GTP version 1 control plane socket */
+	if (create_and_bind_socket("GTPv1 control plane", *gsn, &(*gsn)->fd1c, AF_INET, listen, GTP1C_PORT) < 0)
+		goto error;
+
+	/* Create GTP version 1 user plane socket */
+	if (create_and_bind_socket("GTPv1 user plane", *gsn, &(*gsn)->fd1u, AF_INET, listen, GTP1U_PORT) < 0)
+		goto error;
+
+	/* Start internal queue timer */
+	gtp_queue_timer_start(*gsn);
+
+	return 0;
+error:
+	gtp_free(*gsn);
+	*gsn = NULL;
+	return -1;
+}
+
+int gtp_free(struct gsn_t *gsn)
+{
+
+	/* Cleanup internal queue timer */
+	osmo_timer_del(&gsn->queue_timer);
+
+	/* Clean up retransmit queues */
+	queue_free(gsn->queue_req);
+	queue_free(gsn->queue_resp);
+
+	close(gsn->fd0);
+	close(gsn->fd1c);
+	close(gsn->fd1u);
+
+	rate_ctr_group_free(gsn->ctrg);
+
+	free(gsn);
+	return 0;
+}
+
+/* API: Register create context indication callback */
+int gtp_set_cb_create_context_ind(struct gsn_t *gsn,
+				  int (*cb_create_context_ind) (struct pdp_t *
+								pdp))
+{
+	gsn->cb_create_context_ind = cb_create_context_ind;
+	return 0;
+}
+
+int gtp_retrans(struct gsn_t *gsn)
+{
+	/* dummy API, deprecated. */
+	return 0;
+}
+
+int gtp_retranstimeout(struct gsn_t *gsn, struct timeval *timeout)
+{
+	timeout->tv_sec = 24*60*60;
+	timeout->tv_usec = 0;
+	/* dummy API, deprecated. Return a huge timer to do nothing */
+	return 0;
+}
--- a/gtp/gsn_internal.h
+++ b/gtp/gsn_internal.h
@@ -0,0 +1,4 @@
+#pragma once
+#include <osmocom/core/in46_addr.h>
+
+void gtp_queue_timer_start(struct gsn_t *gsn);
--- a/gtp/gtp.c
+++ b/gtp/gtp.c
--- a/gtp/gtp_internal.h
+++ b/gtp/gtp_internal.h
@@ -0,0 +1,52 @@
+#pragma once
+
+int gtp_echo_resp(struct gsn_t *gsn, int version,
+		  struct sockaddr_in *peer, int fd,
+		  void *pack, unsigned len);
+int gtp_echo_ind(struct gsn_t *gsn, int version,
+		 struct sockaddr_in *peer, int fd,
+		 void *pack, unsigned len);
+int gtp_echo_conf(struct gsn_t *gsn, int version,
+		  struct sockaddr_in *peer, void *pack, unsigned len);
+
+int gtp_unsup_req(struct gsn_t *gsn, int version,
+		  struct sockaddr_in *peer,
+		  int fd, void *pack, unsigned len);
+int gtp_unsup_ind(struct gsn_t *gsn, struct sockaddr_in *peer,
+		  void *pack, unsigned len);
+
+int gtp_create_pdp_resp(struct gsn_t *gsn, int version,
+			struct pdp_t *pdp, uint8_t cause);
+
+int gtp_create_pdp_ind(struct gsn_t *gsn, int version,
+		       struct sockaddr_in *peer, int fd,
+		       void *pack, unsigned len);
+
+int gtp_create_pdp_conf(struct gsn_t *gsn, int version,
+			struct sockaddr_in *peer,
+			void *pack, unsigned len);
+
+int gtp_update_pdp_req(struct gsn_t *gsn, int version, void *cbp,
+		       struct in_addr *inetaddr, struct pdp_t *pdp);
+
+int gtp_delete_pdp_req(struct gsn_t *gsn, int version, void *cbp,
+		       struct pdp_t *pdp);
+
+int gtp_delete_pdp_resp(struct gsn_t *gsn, int version,
+			struct sockaddr_in *peer, int fd,
+			void *pack, unsigned len,
+			struct pdp_t *pdp, struct pdp_t *linked_pdp,
+			uint8_t cause, int teardown);
+
+int gtp_delete_pdp_ind(struct gsn_t *gsn, int version,
+		       struct sockaddr_in *peer, int fd,
+		       void *pack, unsigned len);
+
+int gtp_delete_pdp_conf(struct gsn_t *gsn, int version,
+			struct sockaddr_in *peer,
+			void *pack, unsigned len);
+
+int ipv42eua(struct ul66_t *eua, struct in_addr *src);
+int eua2ipv4(struct in_addr *dst, struct ul66_t *eua);
+int in_addr2gsna(struct ul16_t *gsna, struct in_addr *src);
+uint64_t gtp_imsi_str2gtp(const char *str);
--- a/gtp/gtpie.c
+++ b/gtp/gtpie.c
@@ -1,17 +1,17 @@
-/* 
+/*
 *  OsmoGGSN - Gateway GPRS Support Node
 *  Copyright (C) 2002 Mondru AB.
- * 
+ *
 *  The contents of this file may be used under the terms of the GNU
 *  General Public License Version 2, provided that the above copyright
 *  notice and this permission notice is included in all copies or
 *  substantial portions of the software.
- * 
+ *
 */

 /*
- * gtpie.c: Contains functions to encapsulate and decapsulate GTP 
- * information elements 
+ * gtpie.c: Contains functions to encapsulate and decapsulate GTP
+ * information elements
 *
 *
 * Encapsulation
@@ -37,7 +37,7 @@
 #include <netinet/in.h>
 #include <string.h>

-#include "gtpie.h"
+#include <osmocom/gtp/gtpie.h>

 /*! Encode a TLV type Information Element.
 *  \param[inout] p Pointer to output packet to which IE is appended
--- a/gtp/pdp.c
+++ b/gtp/pdp.c
@@ -28,8 +28,10 @@
 #include <netinet/in.h>
 #include <string.h>
 #include <inttypes.h>
-#include "pdp.h"
-#include "gtp.h"
+
+#include <osmocom/gtp/pdp.h>
+#include <osmocom/gtp/gtp.h>
+
 #include "lookupa.h"
 #include "queue.h"

@@ -338,9 +340,7 @@ int pdp_getimsi(struct pdp_t **pdp, uint64_t imsi, uint8_t nsapi)

 int gtp_pdp_getimsi(struct gsn_t *gsn, struct pdp_t **pdp, uint64_t imsi, uint8_t nsapi)
 {
-	return gtp_pdp_tidget(gsn, pdp,
-			  (imsi & 0x0fffffffffffffffull) +
-			  ((uint64_t) nsapi << 60));
+	return gtp_pdp_tidget(gsn, pdp, pdp_gettid(imsi, nsapi));
 }


--- a/gtp/queue.c
+++ b/gtp/queue.c
@@ -27,8 +27,10 @@
 #include <sys/time.h>
 #include <netinet/in.h>
 #include <string.h>
-#include "pdp.h"
-#include "gtp.h"
+
+#include <osmocom/gtp/pdp.h>
+#include <osmocom/gtp/gtp.h>
+
 #include "queue.h"

 /*! \brief dump a queue_t to stdout */
--- a/gtp/queue.h
+++ b/gtp/queue.h
@@ -19,11 +19,11 @@

 #include <osmocom/core/linuxlist.h>

-#include "gtp.h"
+#include <osmocom/gtp/gtp.h>

 #define QUEUE_DEBUG 0		/* Print debug information */

-#define QUEUE_SIZE 1024		/* Size of retransmission queue */
+#define QUEUE_SIZE (PDP_MAX*2)	/* Size of retransmission queue */
 #define QUEUE_HASH_SIZE 65536	/* Size of hash table (2^16) */

 struct qmsg_t {			/* Holder for queued packets */
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -0,0 +1,3 @@
+SUBDIRS = \
+	osmocom \
+	$(NULL)
--- a/include/osmocom/Makefile.am
+++ b/include/osmocom/Makefile.am
@@ -0,0 +1,3 @@
+SUBDIRS = \
+	gtp \
+	$(NULL)
--- a/include/osmocom/gtp/Makefile.am
+++ b/include/osmocom/gtp/Makefile.am
@@ -0,0 +1,8 @@
+libgtp_HEADERS = \
+	gsn.h \
+	gtp.h \
+	gtpie.h \
+	pdp.h \
+	$(NULL)
+
+libgtpdir = $(includedir)/osmocom/gtp
--- a/include/osmocom/gtp/gsn.h
+++ b/include/osmocom/gtp/gsn.h
@@ -0,0 +1,178 @@
+/*
+ *  OsmoGGSN - Gateway GPRS Support Node
+ *  Copyright (C) 2002, 2003, 2004 Mondru AB.
+ *
+ *  The contents of this file may be used under the terms of the GNU
+ *  General Public License Version 2, provided that the above copyright
+ *  notice and this permission notice is included in all copies or
+ *  substantial portions of the software.
+ *
+ */
+
+#ifndef _GSN_H
+#define _GSN_H
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/defs.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/core/tdef.h>
+#include <osmocom/core/rate_ctr.h>
+
+#include "pdp.h"
+
+#define GTP_MODE_GGSN 1
+#define GTP_MODE_SGSN 2
+
+#define RESTART_FILE "gsn_restart"
+
+extern struct osmo_tdef gtp_T_defs[];
+
+/* ***********************************************************
+ * Information storage for each gsn instance
+ *
+ * Normally each instance of the application corresponds to
+ * one instance of a gsn.
+ *
+ * In order to avoid global variables in the application, and
+ * also in order to allow several instances of a gsn in the same
+ * application this struct is provided in order to store all
+ * relevant information related to the gsn.
+ *
+ * Note that this does not include information storage for '
+ * each pdp context. This is stored in another struct.
+ *************************************************************/
+
+enum gsn_rate_ctr_keys {
+	GSN_CTR_ERR_SOCKET,
+	GSN_CTR_ERR_READFROM,	/* Number of readfrom errors */
+	GSN_CTR_ERR_SENDTO,	/* Number of sendto errors */
+	GSN_CTR_ERR_QUEUEFULL,	/* Number of times queue was full */
+	GSN_CTR_ERR_SEQ,	/* Number of seq out of range */
+	GSN_CTR_ERR_ADDRESS,	/* GSN address conversion failed */
+	GSN_CTR_ERR_UNKNOWN_PDP,	/* GSN address conversion failed */
+	GSN_CTR_ERR_UNEXPECTED_CAUSE,	/* Unexpected cause value received */
+	GSN_CTR_ERR_OUT_OF_PDP,	/* Out of storage for PDP contexts */
+	GSN_CTR_PKT_EMPTY,		/* Number of empty packets */
+	GSN_CTR_PKT_UNSUP,		/* Number of unsupported version 29.60 11.1.1 */
+	GSN_CTR_PKT_TOOSHORT,	/* Number of too short headers 29.60 11.1.2 */
+	GSN_CTR_PKT_UNKNOWN,	/* Number of unknown messages 29.60 11.1.3 */
+	GSN_CTR_PKT_UNEXPECT,	/* Number of unexpected messages 29.60 11.1.4 */
+	GSN_CTR_PKT_DUPLICATE,	/* Number of duplicate or unsolicited replies */
+	GSN_CTR_PKT_MISSING,	/* Number of missing information field messages */
+	GSN_CTR_PKT_INCORRECT,	/* Number of incorrect information field messages */
+	GSN_CTR_PKT_INVALID,	/* Number of invalid message format messages */
+};
+
+/* 3GPP TS 29.006 14.1, 14,2 */
+enum gtp_gsn_timers {
+	GTP_GSN_TIMER_T3_RESPONSE = 3,
+	GTP_GSN_TIMER_N3_REQUESTS = 1003,
+	GTP_GSN_TIMER_T3_HOLD_RESPONSE = -3,
+};
+
+struct gsn_t {
+	/* Parameters related to the network interface */
+
+	int fd0;		/* GTP0 file descriptor */
+	int fd1c;		/* GTP1 control plane file descriptor */
+	int fd1u;		/* GTP0 user plane file descriptor */
+	int mode;		/* Mode of operation: GGSN or SGSN */
+	struct in_addr gsnc;	/* IP address of this gsn for signalling */
+	struct in_addr gsnu;	/* IP address of this gsn for user traffic */
+
+	/* Parameters related to signalling messages */
+	uint16_t seq_next;	/* Next sequence number to use */
+	int seq_first;		/* First packet in queue (oldest timeout) */
+	int seq_last;		/* Last packet in queue (youngest timeout) */
+
+	unsigned char restart_counter;	/* Increment on restart. Stored on disk */
+	char *statedir;		/* Disk location for permanent storage */
+	void *priv;		/* used by libgtp users to attach their own state) */
+	struct queue_t *queue_req;	/* Request queue */
+	struct queue_t *queue_resp;	/* Response queue */
+
+	struct pdp_t pdpa[PDP_MAX];	/* PDP storage */
+	struct pdp_t *hashtid[PDP_MAX];	/* Hash table for IMSI + NSAPI */
+
+	struct osmo_timer_list queue_timer; /* internal queue_{req,resp} timer */
+
+	/* Call back functions */
+	int (*cb_delete_context) (struct pdp_t *);
+	int (*cb_create_context_ind) (struct pdp_t *);
+	int (*cb_unsup_ind) (struct sockaddr_in * peer);
+	int (*cb_extheader_ind) (struct sockaddr_in * peer);
+	int (*cb_ran_info_relay_ind) (struct sockaddr_in *peer, union gtpie_member **ie);
+	int (*cb_conf) (int type, int cause, struct pdp_t * pdp, void *cbp);
+	int (*cb_data_ind) (struct pdp_t * pdp, void *pack, unsigned len);
+	int (*cb_recovery) (struct sockaddr_in * peer, uint8_t recovery);
+	int (*cb_recovery2) (struct sockaddr_in * peer, struct pdp_t * pdp, uint8_t recovery);
+	int (*cb_recovery3) (struct gsn_t *gsn, struct sockaddr_in *peer, struct pdp_t *pdp, uint8_t recovery);
+
+	/* Counters */
+	struct rate_ctr_group *ctrg;
+
+	/* Timers: */
+	struct osmo_tdef *tdef;
+};
+
+/* External API functions */
+
+extern int gtp_new(struct gsn_t **gsn, char *statedir, struct in_addr *listen,
+		   int mode);
+
+extern int gtp_free(struct gsn_t *gsn);
+
+extern int gtp_newpdp(struct gsn_t *gsn, struct pdp_t **pdp,
+		      uint64_t imsi, uint8_t nsapi) OSMO_DEPRECATED("Use gtp_pdp_newpdp() instead");
+extern int gtp_freepdp(struct gsn_t *gsn, struct pdp_t *pdp);
+extern int gtp_freepdp_teardown(struct gsn_t *gsn, struct pdp_t *pdp);
+
+extern int gtp_create_context_req(struct gsn_t *gsn, struct pdp_t *pdp,
+				  void *cbp);
+
+extern int gtp_set_cb_create_context_ind(struct gsn_t *gsn,
+					 int (*cb_create_context_ind) (struct
+								       pdp_t *
+								       pdp));
+extern int gtp_set_cb_data_ind(struct gsn_t *gsn,
+			       int (*cb_data_ind) (struct pdp_t * pdp,
+						   void *pack, unsigned len));
+extern int gtp_set_cb_delete_context(struct gsn_t *gsn,
+				     int (*cb_delete_context) (struct pdp_t *
+							       pdp));
+/*extern int gtp_set_cb_create_context(struct gsn_t *gsn,
+  int (*cb_create_context) (struct pdp_t* pdp)); */
+
+extern int gtp_set_cb_unsup_ind(struct gsn_t *gsn,
+				int (*cb) (struct sockaddr_in * peer));
+
+extern int gtp_set_cb_extheader_ind(struct gsn_t *gsn,
+				    int (*cb) (struct sockaddr_in * peer));
+
+extern int gtp_set_cb_ran_info_relay_ind(struct gsn_t *gsn,
+				    int (*cb) (struct sockaddr_in * peer, union gtpie_member **ie));
+
+extern int gtp_set_cb_conf(struct gsn_t *gsn,
+			   int (*cb) (int type, int cause, struct pdp_t * pdp,
+				      void *cbp));
+
+int gtp_set_cb_recovery(struct gsn_t *gsn,
+			int (*cb) (struct sockaddr_in * peer,
+				   uint8_t recovery))
+	OSMO_DEPRECATED("Use gtp_set_cb_recovery2() instead, to obtain pdp ctx originating the recovery");
+int gtp_set_cb_recovery2(struct gsn_t *gsn,
+			int (*cb) (struct sockaddr_in * peer,
+				   struct pdp_t * pdp,
+				   uint8_t recovery))
+	OSMO_DEPRECATED("Use gtp_set_cb_recovery3() instead, to obtain gsn handling the recovery");
+int gtp_set_cb_recovery3(struct gsn_t *gsn,
+			int (*cb) (struct gsn_t * gsn, struct sockaddr_in * peer,
+				   struct pdp_t * pdp,
+				   uint8_t recovery));
+void gtp_clear_queues(struct gsn_t *gsn);
+extern int gtp_fd(struct gsn_t *gsn);
+
+extern int gtp_retrans(struct gsn_t *gsn) OSMO_DEPRECATED("This API is a no-op, libgtp already does the job internally");
+extern int gtp_retranstimeout(struct gsn_t *gsn, struct timeval *timeout) OSMO_DEPRECATED("This API is a no-op and will return a 1 day timeout");
+
+#endif /* !_GSN_H */
--- a/include/osmocom/gtp/gtp.h
+++ b/include/osmocom/gtp/gtp.h
@@ -13,13 +13,10 @@
 #define _GTP_H

 #include <osmocom/core/utils.h>
-#include <osmocom/core/defs.h>
-#include <osmocom/core/timer.h>

+#include "gtpie.h"
 #include "pdp.h"
-
-#define GTP_MODE_GGSN 1
-#define GTP_MODE_SGSN 2
+#include "gsn.h"

 #define GTP0_PORT	3386
 #define GTP1C_PORT	2123
@@ -31,12 +28,10 @@
 #define GTP1_HEADER_SIZE_SHORT  8
 #define GTP1_HEADER_SIZE_LONG  12

+#define NAMESIZE 1024
 #define SYSLOG_PRINTSIZE 255
 #define ERRMSG_SIZE 255

-#define RESTART_FILE "gsn_restart"
-#define NAMESIZE 1024
-
 /* GTP version 1 extension header type definitions. */
 #define GTP_EXT_PDCP_PDU    0xC0	/* PDCP PDU Number */

@@ -58,7 +53,7 @@
 #define GTP_UPDATE_PDP_RSP   19	/* Update PDP Context Response */
 #define GTP_DELETE_PDP_REQ   20	/* Delete PDP Context Request */
 #define GTP_DELETE_PDP_RSP   21	/* Delete PDP Context Response */
-						       /* 22-25 For future use. *//* In version GTP 1 anonomous PDP context */
+/* 22-25 For future use. *//* In version GTP 1 anonomous PDP context */
 #define GTP_ERROR            26	/* Error Indication */
 #define GTP_PDU_NOT_REQ      27	/* PDU Notification Request */
 #define GTP_PDU_NOT_RSP      28	/* PDU Notification Response */
@@ -85,6 +80,7 @@
 #define GTP_FWD_SRNS         58	/* Forward SRNS Context */
 #define GTP_FWD_RELOC_ACK    59	/* Forward Relocation Complete Acknowledge */
 #define GTP_FWD_SRNS_ACK     60	/* Forward SRNS Context Acknowledge */
+#define GTP_RAN_INFO_RELAY   70	/* RAN Information Relay */
 /* 61-239 For future use. */
 #define GTP_DATA_TRAN_REQ   240	/* Data Record Transfer Request */
 #define GTP_DATA_TRAN_RSP   241	/* Data Record Transfer Response */
@@ -103,19 +99,21 @@ static inline const char *gtp_type_name(uint8_t val)
 #define GTPCAUSE_NO_ID_NEEDED               3	/* No identity needed */
 #define GTPCAUSE_MS_REFUSES_X               4	/* MS refuses */
 #define GTPCAUSE_MS_NOT_RESP_X              5	/* MS is not GPRS responding */
-#define GTPCAUSE_006                        6	/* For future use 6-48 */
-#define GTPCAUSE_049                       49	/* Cause values reserved for GPRS charging protocol use (See GTP' in GSM 12.15) 49-63 */
-#define GTPCAUSE_064                       64	/* For future use 64-127 */
+/* 6-48 For future use */
+/* 49-63 Cause values reserved for GPRS charging protocol use (See GTP' in GSM 12.15) */
+/* 64-127 For future use */
 #define GTPCAUSE_ACC_REQ                  128	/* Request accepted */
-#define GTPCAUSE_129                      129	/* For future use 129-176 */
-#define GTPCAUSE_177                      177	/* Cause values reserved for GPRS charging protocol use (See GTP' In GSM 12.15) 177-191 */
+#define GTPCAUSE_NEW_PDP_NET_PREF         129	/* New PDP type due to network preference */
+#define GTPCAUSE_NEW_PDP_ADDR_BEAR        130	/* New PDP type due to single address bearer only */
+/* 131-176 For future use */
+/* 177-191 Cause values reserved for GPRS charging protocol use (See GTP' In GSM 12.15) */
 #define GTPCAUSE_NON_EXIST                192	/* Non-existent */
 #define GTPCAUSE_INVALID_MESSAGE          193	/* Invalid message format */
 #define GTPCAUSE_IMSI_NOT_KNOWN           194	/* IMSI not known */
 #define GTPCAUSE_MS_DETACHED              195	/* MS is GPRS detached */
 #define GTPCAUSE_MS_NOT_RESP              196	/* MS is not GPRS responding */
 #define GTPCAUSE_MS_REFUSES               197	/* MS refuses */
-#define GTPCAUSE_198                      198	/* For future use */
+/* 198 For future use */
 #define GTPCAUSE_NO_RESOURCES             199	/* No resources available */
 #define GTPCAUSE_NOT_SUPPORTED            200	/* Service not supported */
 #define GTPCAUSE_MAN_IE_INCORRECT         201	/* Mandatory IE incorrect */
@@ -138,8 +136,15 @@ static inline const char *gtp_type_name(uint8_t val)
 #define GTPCAUSE_SYN_ERR_FILTER           218	/* Syntactic errors in packet filter(s) */
 #define GTPCAUSE_MISSING_APN              219	/* Missing or unknown APN */
 #define GTPCAUSE_UNKNOWN_PDP              220	/* Unknown PDP address or PDP type */
-#define GTPCAUSE_221                      221	/* For Future Use 221-240 */
-#define GTPCAUSE_241                      241	/* Cause Values Reserved For Gprs Charging Protocol Use (See Gtp' In Gsm 12.15) 241-255 */
+/* 221-240 For future use */
+/* 241-255 Cause Values Reserved For Gprs Charging Protocol Use (See Gtp' In Gsm 12.15) */
+
+static inline bool gtp_cause_successful(uint8_t cause)
+{
+	return cause == GTPCAUSE_ACC_REQ ||
+		cause == GTPCAUSE_NEW_PDP_NET_PREF ||
+		cause == GTPCAUSE_NEW_PDP_ADDR_BEAR;
+}

 struct ul66_t;
 struct ul16_t;
@@ -230,104 +235,13 @@ union gtp_packet {
 	struct gtp1_packet_long gtp1l;
 } __attribute__ ((packed));

-/* ***********************************************************
- * Information storage for each gsn instance
- *
- * Normally each instance of the application corresponds to
- * one instance of a gsn.
- *
- * In order to avoid global variables in the application, and
- * also in order to allow several instances of a gsn in the same
- * application this struct is provided in order to store all
- * relevant information related to the gsn.
- *
- * Note that this does not include information storage for '
- * each pdp context. This is stored in another struct.
- *************************************************************/
-
-struct gsn_t {
-	/* Parameters related to the network interface */
-
-	int fd0;		/* GTP0 file descriptor */
-	int fd1c;		/* GTP1 control plane file descriptor */
-	int fd1u;		/* GTP0 user plane file descriptor */
-	int mode;		/* Mode of operation: GGSN or SGSN */
-	struct in_addr gsnc;	/* IP address of this gsn for signalling */
-	struct in_addr gsnu;	/* IP address of this gsn for user traffic */
-
-	/* Parameters related to signalling messages */
-	uint16_t seq_next;	/* Next sequence number to use */
-	int seq_first;		/* First packet in queue (oldest timeout) */
-	int seq_last;		/* Last packet in queue (youngest timeout) */
-
-	unsigned char restart_counter;	/* Increment on restart. Stored on disk */
-	char *statedir;		/* Disk location for permanent storage */
-	void *priv;		/* used by libgtp users to attach their own state) */
-	struct queue_t *queue_req;	/* Request queue */
-	struct queue_t *queue_resp;	/* Response queue */
-
-	struct pdp_t pdpa[PDP_MAX];	/* PDP storage */
-	struct pdp_t *hashtid[PDP_MAX];	/* Hash table for IMSI + NSAPI */
-
-	struct osmo_timer_list queue_timer; /* internal queue_{req,resp} timer */
-
-	/* Call back functions */
-	int (*cb_delete_context) (struct pdp_t *);
-	int (*cb_create_context_ind) (struct pdp_t *);
-	int (*cb_unsup_ind) (struct sockaddr_in * peer);
-	int (*cb_extheader_ind) (struct sockaddr_in * peer);
-	int (*cb_conf) (int type, int cause, struct pdp_t * pdp, void *cbp);
-	int (*cb_data_ind) (struct pdp_t * pdp, void *pack, unsigned len);
-	int (*cb_recovery) (struct sockaddr_in * peer, uint8_t recovery);
-	int (*cb_recovery2) (struct sockaddr_in * peer, struct pdp_t * pdp, uint8_t recovery);
-	int (*cb_recovery3) (struct gsn_t *gsn, struct sockaddr_in *peer, struct pdp_t *pdp, uint8_t recovery);
-
-	/* Counters */
-
-	uint64_t err_socket;	/* Number of socket errors */
-	uint64_t err_readfrom;	/* Number of readfrom errors */
-	uint64_t err_sendto;	/* Number of sendto errors */
-	uint64_t err_memcpy;	/* Number of memcpy */
-	uint64_t err_queuefull;	/* Number of times queue was full */
-	uint64_t err_seq;	/* Number of seq out of range */
-	uint64_t err_address;	/* GSN address conversion failed */
-	uint64_t err_unknownpdp;	/* GSN address conversion failed */
-	uint64_t err_unknowntid;	/* Application supplied unknown imsi+nsapi */
-	uint64_t err_cause;	/* Unexpected cause value received */
-	uint64_t err_outofpdp;	/* Out of storage for PDP contexts */
-
-	uint64_t empty;		/* Number of empty packets */
-	uint64_t unsup;		/* Number of unsupported version 29.60 11.1.1 */
-	uint64_t tooshort;	/* Number of too short headers 29.60 11.1.2 */
-	uint64_t unknown;	/* Number of unknown messages 29.60 11.1.3 */
-	uint64_t unexpect;	/* Number of unexpected messages 29.60 11.1.4 */
-	uint64_t duplicate;	/* Number of duplicate or unsolicited replies */
-	uint64_t missing;	/* Number of missing information field messages */
-	uint64_t incorrect;	/* Number of incorrect information field messages */
-	uint64_t invalid;	/* Number of invalid message format messages */
-};
-
 /* External API functions */

 extern const char *gtp_version();
-extern int gtp_new(struct gsn_t **gsn, char *statedir, struct in_addr *listen,
-		   int mode);
-
-extern int gtp_free(struct gsn_t *gsn);
-
-extern int gtp_newpdp(struct gsn_t *gsn, struct pdp_t **pdp,
-		      uint64_t imsi, uint8_t nsapi) OSMO_DEPRECATED("Use gtp_pdp_newpdp() instead");
-extern int gtp_freepdp(struct gsn_t *gsn, struct pdp_t *pdp);
-extern int gtp_freepdp_teardown(struct gsn_t *gsn, struct pdp_t *pdp);

 extern int gtp_create_context_req(struct gsn_t *gsn, struct pdp_t *pdp,
 				  void *cbp);

-extern int gtp_set_cb_create_context_ind(struct gsn_t *gsn,
-					 int (*cb_create_context_ind) (struct
-								       pdp_t *
-								       pdp));
-
 extern int gtp_create_context_resp(struct gsn_t *gsn, struct pdp_t *pdp,
 				   int cause);

@@ -343,103 +257,20 @@ extern int gtp_delete_context_req2(struct gsn_t *gsn, struct pdp_t *pdp,
 extern int gtp_data_req(struct gsn_t *gsn, struct pdp_t *pdp,
 			void *pack, unsigned len);

-extern int gtp_set_cb_data_ind(struct gsn_t *gsn,
-			       int (*cb_data_ind) (struct pdp_t * pdp,
-						   void *pack, unsigned len));
+extern int gtp_ran_info_relay_req(struct gsn_t *gsn, const struct sockaddr_in *peer,
+				  const uint8_t *ran_container, size_t ran_container_len,
+				  const uint8_t *rim_route_addr, size_t rim_route_addr_len,
+				  uint8_t rim_route_addr_discr);

-extern int gtp_fd(struct gsn_t *gsn);
 extern int gtp_decaps0(struct gsn_t *gsn);
 extern int gtp_decaps1c(struct gsn_t *gsn);
 extern int gtp_decaps1u(struct gsn_t *gsn);
-extern int gtp_retrans(struct gsn_t *gsn) OSMO_DEPRECATED("This API is a no-op, libgtp already does the job internally");
-extern int gtp_retranstimeout(struct gsn_t *gsn, struct timeval *timeout) OSMO_DEPRECATED("This API is a no-op and will return a 1 day timeout");
-
-extern int gtp_set_cb_delete_context(struct gsn_t *gsn,
-				     int (*cb_delete_context) (struct pdp_t *
-							       pdp));
-/*extern int gtp_set_cb_create_context(struct gsn_t *gsn,
-  int (*cb_create_context) (struct pdp_t* pdp)); */
-
-extern int gtp_set_cb_unsup_ind(struct gsn_t *gsn,
-				int (*cb) (struct sockaddr_in * peer));
-
-extern int gtp_set_cb_extheader_ind(struct gsn_t *gsn,
-				    int (*cb) (struct sockaddr_in * peer));
-
-extern int gtp_set_cb_conf(struct gsn_t *gsn,
-			   int (*cb) (int type, int cause, struct pdp_t * pdp,
-				      void *cbp));
-
-int gtp_set_cb_recovery(struct gsn_t *gsn,
-			int (*cb) (struct sockaddr_in * peer,
-				   uint8_t recovery))
-	OSMO_DEPRECATED("Use gtp_set_cb_recovery2() instead, to obtain pdp ctx originating the recovery");
-int gtp_set_cb_recovery2(struct gsn_t *gsn,
-			int (*cb) (struct sockaddr_in * peer,
-				   struct pdp_t * pdp,
-				   uint8_t recovery))
-	OSMO_DEPRECATED("Use gtp_set_cb_recovery3() instead, to obtain gsn handling the recovery");;
-int gtp_set_cb_recovery3(struct gsn_t *gsn,
-			int (*cb) (struct gsn_t * gsn, struct sockaddr_in * peer,
-				   struct pdp_t * pdp,
-				   uint8_t recovery));
-
-void gtp_clear_queues(struct gsn_t *gsn);
-
-/* Internal functions (not part of the API */

 extern int gtp_echo_req(struct gsn_t *gsn, int version, void *cbp,
 			struct in_addr *inetaddrs);
-extern int gtp_echo_resp(struct gsn_t *gsn, int version,
-			 struct sockaddr_in *peer, int fd,
-			 void *pack, unsigned len);
-extern int gtp_echo_ind(struct gsn_t *gsn, int version,
-			struct sockaddr_in *peer, int fd,
-			void *pack, unsigned len);
-extern int gtp_echo_conf(struct gsn_t *gsn, int version,
-			 struct sockaddr_in *peer, void *pack, unsigned len);

-extern int gtp_unsup_req(struct gsn_t *gsn, int version,
-			 struct sockaddr_in *peer,
-			 int fd, void *pack, unsigned len);
-extern int gtp_unsup_ind(struct gsn_t *gsn, struct sockaddr_in *peer,
-			 void *pack, unsigned len);
-
-extern int gtp_create_pdp_resp(struct gsn_t *gsn, int version,
-			       struct pdp_t *pdp, uint8_t cause);
-
-extern int gtp_create_pdp_ind(struct gsn_t *gsn, int version,
-			      struct sockaddr_in *peer, int fd,
-			      void *pack, unsigned len);
-
-extern int gtp_create_pdp_conf(struct gsn_t *gsn, int version,
-			       struct sockaddr_in *peer,
-			       void *pack, unsigned len);
-
-extern int gtp_update_pdp_req(struct gsn_t *gsn, int version, void *cbp,
-			      struct in_addr *inetaddr, struct pdp_t *pdp);
-
-extern int gtp_delete_pdp_req(struct gsn_t *gsn, int version, void *cbp,
-			      struct pdp_t *pdp);
-
-extern int gtp_delete_pdp_resp(struct gsn_t *gsn, int version,
-			       struct sockaddr_in *peer, int fd,
-			       void *pack, unsigned len,
-			       struct pdp_t *pdp, struct pdp_t *linked_pdp,
-			       uint8_t cause, int teardown);
-
-extern int gtp_delete_pdp_ind(struct gsn_t *gsn, int version,
-			      struct sockaddr_in *peer, int fd,
-			      void *pack, unsigned len);
-
-extern int gtp_delete_pdp_conf(struct gsn_t *gsn, int version,
-			       struct sockaddr_in *peer,
-			       void *pack, unsigned len);
-
-extern int ipv42eua(struct ul66_t *eua, struct in_addr *src);
-extern int eua2ipv4(struct in_addr *dst, struct ul66_t *eua);
 extern int gsna2in_addr(struct in_addr *dst, struct ul16_t *gsna);
-extern int in_addr2gsna(struct ul16_t *gsna, struct in_addr *src);
+
 extern const char *imsi_gtp2str(const uint64_t *imsi);

 #endif /* !_GTP_H */
--- a/include/osmocom/gtp/gtpie.h
+++ b/include/osmocom/gtp/gtpie.h
--- a/include/osmocom/gtp/pdp.h
+++ b/include/osmocom/gtp/pdp.h
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,10 +1,42 @@
 noinst_LIBRARIES = libmisc.a

-noinst_HEADERS = gnugetopt.h ippool.h lookup.h syserr.h tun.h in46_addr.h netdev.h gtp-kernel.h netns.h util.h icmpv6.h checksum.h
+noinst_HEADERS = \
+		 checksum.h \
+		 gnugetopt.h \
+		 gtp-kernel.h \
+		 icmpv6.h \
+		 in46_addr.h \
+		 ippool.h \
+		 lookup.h \
+		 netdev.h \
+		 netns.h \
+		 syserr.h \
+		 tun.h \
+		 util.h \
+		 $(NULL)

-AM_CFLAGS = -O2 -fno-builtin -Wall -DSBINDIR='"$(sbindir)"' -ggdb $(LIBOSMOCORE_CFLAGS)
+AM_CFLAGS = \
+	    -fno-builtin \
+	    -Wall \
+	    -DSBINDIR='"$(sbindir)"' \
+	    -I$(top_srcdir)/include \
+	    $(LIBOSMOCORE_CFLAGS) \
+	    $(NULL)

-libmisc_a_SOURCES = getopt1.c getopt.c ippool.c lookup.c tun.c debug.c in46_addr.c netdev.c netns.c util.c icmpv6.c checksum.c
+libmisc_a_SOURCES = \
+		    checksum.c \
+		    debug.c \
+		    getopt.c \
+		    getopt1.c \
+		    icmpv6.c \
+		    in46_addr.c \
+		    ippool.c \
+		    lookup.c \
+		    netdev.c \
+		    netns.c \
+		    tun.c \
+		    util.c \
+		    $(NULL)

 if ENABLE_GTP_KERNEL
 AM_CFLAGS += -DGTP_KERNEL $(LIBGTPNL_CFLAGS)
--- a/lib/gtp-kernel.c
+++ b/lib/gtp-kernel.c
@@ -18,22 +18,18 @@

 #include <libgtpnl/gtp.h>
 #include <libgtpnl/gtpnl.h>
-#include <libmnl/libmnl.h>

 #include <errno.h>

 #include <time.h>

+#include <osmocom/gtp/pdp.h>
+#include <osmocom/gtp/gtp.h>
+
 #include "../lib/tun.h"
 #include "../lib/syserr.h"
 #include "../lib/util.h"
 #include "../lib/ippool.h"
-#include "../gtp/pdp.h"
-#include "../gtp/gtp.h"
-
-#include <libgtpnl/gtp.h>
-#include <libgtpnl/gtpnl.h>
-#include <libmnl/libmnl.h>

 #include "gtp-kernel.h"

@@ -109,61 +105,97 @@ void gtp_kernel_stop(const char *devname)

 int gtp_kernel_tunnel_add(struct pdp_t *pdp, const char *devname)
 {
-	struct in_addr ms, sgsn;
+	int ms_addr_count;
+	struct in46_addr ms[2];
+	struct in46_addr sgsn;
 	struct gtp_tunnel *t;
-	int ret;
+	int ret = 0;

 	pdp_debug(__func__, devname, pdp);

-	t = gtp_tunnel_alloc();
-	if (t == NULL)
+	in46a_from_gsna(&pdp->gsnrc, &sgsn);
+
+	ms_addr_count = in46a_from_eua(&pdp->eua, ms);
+	if (ms_addr_count < 0)
 		return -1;

-	memcpy(&ms, &pdp->eua.v[2], sizeof(struct in_addr));
-	memcpy(&sgsn, &pdp->gsnrc.v[0], sizeof(struct in_addr));
+	for (int i = 0; i < ms_addr_count; i++) {
+		t = gtp_tunnel_alloc();
+		if (t == NULL)
+			return -1;

-	gtp_tunnel_set_ifidx(t, if_nametoindex(devname));
-	gtp_tunnel_set_version(t, pdp->version);
-	gtp_tunnel_set_ms_ip4(t, &ms);
-	gtp_tunnel_set_sgsn_ip4(t, &sgsn);
-	if (pdp->version == 0) {
-		gtp_tunnel_set_tid(t, pdp_gettid(pdp->imsi, pdp->nsapi));
-		gtp_tunnel_set_flowid(t, pdp->flru);
-	} else {
-		gtp_tunnel_set_i_tei(t, pdp->teid_own);
-		/* use the TEI advertised by SGSN when sending packets
-		 * towards the SGSN */
-		gtp_tunnel_set_o_tei(t, pdp->teid_gn);
+		gtp_tunnel_set_ifidx(t, if_nametoindex(devname));
+		gtp_tunnel_set_version(t, pdp->version);
+
+		if (in46a_to_af(&ms[i]) == AF_INET)
+			gtp_tunnel_set_ms_ip4(t, &ms[i].v4);
+		else {
+			/* In IPv6, EUA doesn't contain the actual IP
+			 * addr/prefix. Set higher bits to 0 to get the 64 bit
+			 * netmask. */
+			memset(((void *)&ms[i].v6) + 8, 0, 8);
+			gtp_tunnel_set_ms_ip6(t, &ms[i].v6);
+		}
+
+		if (in46a_to_af(&sgsn) == AF_INET)
+			gtp_tunnel_set_sgsn_ip4(t, &sgsn.v4);
+		else
+			gtp_tunnel_set_sgsn_ip6(t, &sgsn.v6);
+
+		if (pdp->version == 0) {
+			gtp_tunnel_set_tid(t, pdp_gettid(pdp->imsi, pdp->nsapi));
+			gtp_tunnel_set_flowid(t, pdp->flru);
+		} else {
+			gtp_tunnel_set_i_tei(t, pdp->teid_own);
+			/* use the TEI advertised by SGSN when sending packets
+			 * towards the SGSN */
+			gtp_tunnel_set_o_tei(t, pdp->teid_gn);
+		}
+
+		ret = gtp_add_tunnel(gtp_nl.genl_id, gtp_nl.nl, t);
+		gtp_tunnel_free(t);
+
+		if (ret != 0)
+			break;
 	}

-	ret = gtp_add_tunnel(gtp_nl.genl_id, gtp_nl.nl, t);
-	gtp_tunnel_free(t);
-
 	return ret;
 }

 int gtp_kernel_tunnel_del(struct pdp_t *pdp, const char *devname)
 {
+	int ms_addr_count;
+	struct in46_addr ms[2];
 	struct gtp_tunnel *t;
-	int ret;
+	int ret = 0;

 	pdp_debug(__func__, devname, pdp);

-	t = gtp_tunnel_alloc();
-	if (t == NULL)
+	ms_addr_count = in46a_from_eua(&pdp->eua, ms);
+	if (ms_addr_count < 0)
 		return -1;

-	gtp_tunnel_set_ifidx(t, if_nametoindex(devname));
-	gtp_tunnel_set_version(t, pdp->version);
-	if (pdp->version == 0) {
-		gtp_tunnel_set_tid(t, pdp_gettid(pdp->imsi, pdp->nsapi));
-		gtp_tunnel_set_flowid(t, pdp->flru);
-	} else {
-		gtp_tunnel_set_i_tei(t, pdp->teid_own);
-	}
+	for (int i = 0; i < ms_addr_count; i++) {
+		t = gtp_tunnel_alloc();
+		if (t == NULL)
+			return -1;

-	ret = gtp_del_tunnel(gtp_nl.genl_id, gtp_nl.nl, t);
-	gtp_tunnel_free(t);
+		gtp_tunnel_set_ifidx(t, if_nametoindex(devname));
+		gtp_tunnel_set_family(t, in46a_to_af(&ms[i]));
+		gtp_tunnel_set_version(t, pdp->version);
+		if (pdp->version == 0) {
+			gtp_tunnel_set_tid(t, pdp_gettid(pdp->imsi, pdp->nsapi));
+			gtp_tunnel_set_flowid(t, pdp->flru);
+		} else {
+			gtp_tunnel_set_i_tei(t, pdp->teid_own);
+		}
+
+		ret = gtp_del_tunnel(gtp_nl.genl_id, gtp_nl.nl, t);
+		gtp_tunnel_free(t);
+
+		if (ret != 0)
+			break;
+	}

 	return ret;
 }
--- a/lib/icmpv6.c
+++ b/lib/icmpv6.c
@@ -21,10 +21,11 @@

 #include <osmocom/core/msgb.h>
 #include <osmocom/core/utils.h>
-#include "checksum.h"

-#include "../gtp/gtp.h"
-#include "../gtp/pdp.h"
+#include <osmocom/gtp/gtp.h>
+#include <osmocom/gtp/pdp.h>
+
+#include "checksum.h"
 #include "ippool.h"
 #include "syserr.h"
 #include "icmpv6.h"
--- a/lib/icmpv6.h
+++ b/lib/icmpv6.h
@@ -5,8 +5,8 @@
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/endian.h>

-#include "../gtp/gtp.h"
-#include "../gtp/pdp.h"
+#include <osmocom/gtp/gtp.h>
+#include <osmocom/gtp/pdp.h>

 #define ICMPv6_OPT_TYPE_PREFIX_INFO 0x03

@@ -44,10 +44,9 @@ struct icmpv6_radv_hdr {
 	uint8_t res:6,
 		m:1,
 		o:1;
-#else
-	uint8_t m:1,
-		o:1,
-		res:6;
+#elif OSMO_IS_BIG_ENDIAN
+/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */
+	uint8_t o:1, m:1, res:6;
 #endif
 	uint16_t router_lifetime;
 	uint32_t reachable_time;
@@ -72,10 +71,9 @@ struct icmpv6_opt_prefix {
 	uint8_t res:6,
 		a:1,
 		l:1;
-#else
-	uint8_t l:1,
-		a:1,
-		res:6;
+#elif OSMO_IS_BIG_ENDIAN
+/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */
+	uint8_t l:1, a:1, res:6;
 #endif
 	uint32_t valid_lifetime;
 	uint32_t preferred_lifetime;
--- a/lib/in46_addr.c
+++ b/lib/in46_addr.c
@@ -10,7 +10,7 @@
 */

 #include "../lib/in46_addr.h"
-#include "../gtp/pdp.h"
+#include <osmocom/gtp/pdp.h>

 #include <osmocom/core/utils.h>

@@ -375,3 +375,10 @@ default_to_dyn_v4:
 	dst->v4.s_addr = 0;
 	return 1;
 }
+
+void in46a_from_gsna(const struct ul16_t *in, struct in46_addr *dst)
+{
+	dst->len = in->l;
+	OSMO_ASSERT(in->l <= sizeof(dst->v6));
+	memcpy(&dst->v6, in->v, in->l);
+}
--- a/lib/in46_addr.h
+++ b/lib/in46_addr.h
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include <netinet/in.h>

-#include "../gtp/pdp.h"
+#include <osmocom/gtp/pdp.h>

 /* a simple wrapper around an in6_addr to also contain the length of the address,
 * thereby implicitly indicating the address family of the address */
@@ -39,3 +39,5 @@ static inline bool in46a_is_v6(const struct in46_addr *addr) {
 static inline bool in46a_is_v4(const struct in46_addr *addr) {
 	return addr->len == sizeof(struct in_addr);
 }
+
+void in46a_from_gsna(const struct ul16_t *in, struct in46_addr *dst);
--- a/lib/ippool.h
+++ b/lib/ippool.h
@@ -13,7 +13,7 @@
 #define _IPPOOL_H

 #include "../lib/in46_addr.h"
-#include "../gtp/gtp.h"
+#include <osmocom/gtp/gtp.h>

 /* Assuming that the address space is fragmented we need a hash table
   in order to return the addresses.
--- a/lib/tun.c
+++ b/lib/tun.c
@@ -318,7 +318,14 @@ int tun_decaps(struct tun_t *this)

 int tun_encaps(struct tun_t *tun, void *pack, unsigned len)
 {
-	return write(tun->fd, pack, len);
+	int rc;
+	rc = write(tun->fd, pack, len);
+	if (rc < 0) {
+		SYS_ERR(DTUN, LOGL_ERROR, errno, "TUN(%s): write() failed", tun->devname);
+	} else if (rc < len) {
+		LOGTUN(LOGL_ERROR, tun, "short write() %d < %u\n", rc, len);
+	}
+	return rc;
 }

 int tun_runscript(struct tun_t *tun, char *script)
--- a/lib/tun.h
+++ b/lib/tun.h
@@ -59,4 +59,7 @@ extern int tun_runscript(struct tun_t *tun, char *script);
 int tun_ip_local_get(const struct tun_t *tun, struct in46_prefix *prefix_list,
 		     size_t prefix_size, int flags);

+#define LOGTUN(level, tun, fmt, args...) \
+	LOGP(DTUN, level, "TUN(%s): " fmt, (tun)->devname, ## args)
+
 #endif /* !_TUN_H */
--- a/lib/util.c
+++ b/lib/util.c
@@ -9,7 +9,7 @@
 *
 */

-#include "../gtp/pdp.h"
+#include <osmocom/gtp/pdp.h>

 #include "ippool.h"
 #include "in46_addr.h"
--- a/libgtp.pc.in
+++ b/libgtp.pc.in
@@ -7,5 +7,8 @@ Name: OsmoGGSN GTP Library
 Description: C Utility Library
 Version: @VERSION@
 Libs: -L${libdir} -lgtp
-Cflags: -I${includedir}/

+# Add two include paths to support:
+# * #include <osmocom/gtp/gtp.h> (like other Osmocom headers)
+# * #include <gtp.h> (legacy compat)
+Cflags: -I${includedir}/osmocom/gtp/ -I${includedir}/
--- a/sgsnemu/Makefile.am
+++ b/sgsnemu/Makefile.am
@@ -2,12 +2,22 @@ bin_PROGRAMS = sgsnemu

 AM_LDFLAGS = @EXEC_LDFLAGS@

-AM_CFLAGS = -O2 -D_GNU_SOURCE -fno-builtin -Wall -DSBINDIR='"$(sbindir)"' -ggdb $(LIBOSMOCORE_CFLAGS)
+AM_CFLAGS = \
+	    -D_GNU_SOURCE \
+	    -fno-builtin \
+	    -Wall \
+	    -DSBINDIR='"$(sbindir)"' \
+	    -I$(top_srcdir)/include \
+	    $(LIBOSMOCORE_CFLAGS) \
+	    $(NULL)

 sgsnemu_LDADD = @EXEC_LDADD@ -lgtp -L../gtp ../lib/libmisc.a $(LIBOSMOCORE_LIBS)

 if ENABLE_GTP_KERNEL
-AM_CFLAGS += -DGTP_KERNEL $(LIBGTPNL_CFLAGS)
+AM_CFLAGS += \
+	     -DGTP_KERNEL \
+	     $(LIBGTPNL_CFLAGS) \
+	     $(NULL)
 sgsnemu_LDADD += $(LIBGTPNL_LIBS)
 endif

--- a/sgsnemu/sgsnemu.c
+++ b/sgsnemu/sgsnemu.c
@@ -54,13 +54,15 @@
 #endif // HAVE_IN6_ADDR_GEN_MODE_NONE
 #endif

+#include <osmocom/gtp/pdp.h>
+#include <osmocom/gtp/gtp.h>
+
 #include "../lib/tun.h"
 #include "../lib/ippool.h"
 #include "../lib/syserr.h"
 #include "../lib/netns.h"
 #include "../lib/icmpv6.h"
-#include "../gtp/pdp.h"
-#include "../gtp/gtp.h"
+#include "../gtp/gtp_internal.h"
 #include "cmdline.h"

 #define IPADDRLEN 256		/* Character length of addresses */
@@ -492,27 +494,12 @@ static int process_options(int argc, char **argv)
 	}

 	/* imsi                                                            */
-	if (strlen(args_info.imsi_arg) != 15) {
+	if (strlen(args_info.imsi_arg) < 6 || strlen(args_info.imsi_arg) > 15) {
 		printf("Invalid IMSI\n");
 		return -1;
 	}

-	options.imsi = 0xf000000000000000ull;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[0] - 48));
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[1] - 48)) << 4;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[2] - 48)) << 8;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[3] - 48)) << 12;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[4] - 48)) << 16;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[5] - 48)) << 20;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[6] - 48)) << 24;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[7] - 48)) << 28;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[8] - 48)) << 32;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[9] - 48)) << 36;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[10] - 48)) << 40;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[11] - 48)) << 44;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[12] - 48)) << 48;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[13] - 48)) << 52;
-	options.imsi |= ((uint64_t) (args_info.imsi_arg[14] - 48)) << 56;
+	options.imsi = gtp_imsi_str2gtp(args_info.imsi_arg);

 	printf("IMSI is:               %s (%#08llx)\n",
 	       args_info.imsi_arg, options.imsi);
--- a/tests/gtp/Makefile.am
+++ b/tests/gtp/Makefile.am
@@ -1,11 +1,16 @@
-AM_CFLAGS = -Wall -I$(top_srcdir)/include $(LIBOSMOCORE_CFLAGS) -g
+AM_CFLAGS = \
+	    -Wall \
+	    -I$(top_srcdir)/include \
+	    $(LIBOSMOCORE_CFLAGS) \
+	    $(NULL)
+AM_LDFLAGS = -no-install

 EXTRA_DIST = \
 	gtpie_test.ok \
 	queue_test.ok \
 	$(NULL)

-noinst_PROGRAMS = \
+check_PROGRAMS = \
 	gtpie_test \
 	queue_test \
 	$(NULL)
--- a/tests/gtp/gtpie_test.c
+++ b/tests/gtp/gtpie_test.c
@@ -10,8 +10,9 @@
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/bits.h>

+#include <osmocom/gtp/gtpie.h>
+
 #include "../../lib/syserr.h"
-#include "../../gtp/gtpie.h"

 static const uint8_t in[] = { 1,2,3,4,5,6 };
 static uint8_t buf[256];
@@ -113,7 +114,7 @@ int main(int argc, char **argv)
 	msgb_talloc_ctx_init(tall_ctx, 0);
 	osmo_init_logging2(tall_ctx, &log_info);
 	log_set_use_color(osmo_stderr_target, 0);
-	log_set_print_filename(osmo_stderr_target, 0);
+	log_set_print_filename2(osmo_stderr_target, LOG_FILENAME_NONE);

 	srand(time(NULL));

--- a/tests/gtp/queue_test.c
+++ b/tests/gtp/queue_test.c
@@ -223,7 +223,7 @@ int main(int argc, char **argv)
 	msgb_talloc_ctx_init(tall_ctx, 0);
 	osmo_init_logging2(tall_ctx, &log_info);
 	log_set_use_color(osmo_stderr_target, 0);
-	log_set_print_filename(osmo_stderr_target, 0);
+	log_set_print_filename2(osmo_stderr_target, LOG_FILENAME_NONE);

 	test_queue_empty();
 	test_queue_one();
--- a/tests/gtp/queue_test.ok
+++ b/tests/gtp/queue_test.ok
--- a/tests/lib/Makefile.am
+++ b/tests/lib/Makefile.am
@@ -1,4 +1,9 @@
-AM_CFLAGS = -Wall -I$(top_srcdir)/include $(LIBOSMOCORE_CFLAGS) -g
+AM_CFLAGS = \
+	    -Wall \
+	    -I$(top_srcdir)/include \
+	    $(LIBOSMOCORE_CFLAGS) \
+	    $(NULL)
+AM_LDFLAGS = -no-install

 EXTRA_DIST = ippool_test.ok \
 	     ippool_test.err \
@@ -7,7 +12,7 @@ EXTRA_DIST = ippool_test.ok \
 	     in46a_test.ok \
 	     in46a_v6_test.ok

-noinst_PROGRAMS = ippool_test in46a_test
+check_PROGRAMS = ippool_test in46a_test

 ippool_test_SOURCES = \
 	ippool_test.c \
--- a/tests/lib/in46a_test.c
+++ b/tests/lib/in46a_test.c
@@ -146,7 +146,7 @@ static void test_in46a_to_eua(void)

 static void test_in46a_from_eua(void)
 {
-	struct in46_addr ia;
+	struct in46_addr ia[2];
 	struct ul66_t eua;
 	const uint8_t v4_unspec[] = { PDP_EUA_ORG_IETF, PDP_EUA_TYPE_v4 };
 	const uint8_t v4_spec[] = { PDP_EUA_ORG_IETF, PDP_EUA_TYPE_v4, 1,2,3,4 };
@@ -155,35 +155,35 @@ static void test_in46a_from_eua(void)
 	printf("Testing in46a_from_eua() with IPv4 addresses\n");

 	/* default: v4 unspec */
-	OSMO_ASSERT(in46a_from_eua(&eua, &ia) == 1);
-	OSMO_ASSERT(ia.len == 4);
-	OSMO_ASSERT(ia.v4.s_addr == 0);
+	OSMO_ASSERT(in46a_from_eua(&eua, ia) == 1);
+	OSMO_ASSERT(ia[0].len == 4);
+	OSMO_ASSERT(ia[0].v4.s_addr == 0);

 	/* invalid */
 	eua.v[0] = 0x23;
 	eua.v[1] = PDP_EUA_TYPE_v4;
 	eua.l = 6;
-	OSMO_ASSERT(in46a_from_eua(&eua, &ia) < 0);
+	OSMO_ASSERT(in46a_from_eua(&eua, ia) < 0);

 	/* invalid */
 	eua.v[0] = PDP_EUA_ORG_IETF;
 	eua.v[1] = 0x23;
 	eua.l = 6;
-	OSMO_ASSERT(in46a_from_eua(&eua, &ia) < 0);
+	OSMO_ASSERT(in46a_from_eua(&eua, ia) < 0);

 	/* unspecified V4 */
 	memcpy(eua.v, v4_unspec, sizeof(v4_unspec));
 	eua.l = sizeof(v4_unspec);
-	OSMO_ASSERT(in46a_from_eua(&eua, &ia) == 1);
-	OSMO_ASSERT(ia.len == 4);
-	OSMO_ASSERT(ia.v4.s_addr == 0);
+	OSMO_ASSERT(in46a_from_eua(&eua, ia) == 1);
+	OSMO_ASSERT(ia[0].len == 4);
+	OSMO_ASSERT(ia[0].v4.s_addr == 0);

 	/* specified V4 */
 	memcpy(eua.v, v4_spec, sizeof(v4_spec));
 	eua.l = sizeof(v4_spec);
-	OSMO_ASSERT(in46a_from_eua(&eua, &ia) == 1);
-	OSMO_ASSERT(ia.len == 4);
-	OSMO_ASSERT(ia.v4.s_addr == htonl(0x01020304));
+	OSMO_ASSERT(in46a_from_eua(&eua, ia) == 1);
+	OSMO_ASSERT(ia[0].len == 4);
+	OSMO_ASSERT(ia[0].v4.s_addr == htonl(0x01020304));
 }

 static void test_in46a_netmasklen(void)
@@ -318,7 +318,7 @@ static void test_in46a_to_eua_v4v6() {

 static void test_in46a_from_eua_v6(void)
 {
-	struct in46_addr ia;
+	struct in46_addr ia[2];
 	struct ul66_t eua;
 	const uint8_t v6_unspec[] = { PDP_EUA_ORG_IETF, PDP_EUA_TYPE_v6 };
 	const uint8_t v6_spec[] = { PDP_EUA_ORG_IETF, PDP_EUA_TYPE_v6,
@@ -331,16 +331,16 @@ static void test_in46a_from_eua_v6(void)
 	/* unspecified V6 */
 	memcpy(eua.v, v6_unspec, sizeof(v6_unspec));
 	eua.l = sizeof(v6_unspec);
-	OSMO_ASSERT(in46a_from_eua(&eua, &ia) == 1);
-	OSMO_ASSERT(ia.len == 16);
-	OSMO_ASSERT(IN6_IS_ADDR_UNSPECIFIED(&ia.v6));
+	OSMO_ASSERT(in46a_from_eua(&eua, ia) == 1);
+	OSMO_ASSERT(ia[0].len == 16);
+	OSMO_ASSERT(IN6_IS_ADDR_UNSPECIFIED(&ia[0].v6));

 	/* specified V6 */
 	memcpy(eua.v, v6_spec, sizeof(v6_spec));
 	eua.l = sizeof(v6_spec);
-	OSMO_ASSERT(in46a_from_eua(&eua, &ia) == 1);
-	OSMO_ASSERT(ia.len == 16);
-	OSMO_ASSERT(!memcmp(&ia.v6, v6_spec+2, ia.len));
+	OSMO_ASSERT(in46a_from_eua(&eua, ia) == 1);
+	OSMO_ASSERT(ia[0].len == 16);
+	OSMO_ASSERT(!memcmp(&ia[0].v6, v6_spec+2, ia[0].len));
 }

 static void test_in46a_from_eua_v4v6(void) {
@@ -431,7 +431,7 @@ int main(int argc, char **argv)
 	msgb_talloc_ctx_init(tall_ctx, 0);
 	osmo_init_logging2(tall_ctx, &log_info);
 	log_set_use_color(osmo_stderr_target, 0);
-	log_set_print_filename(osmo_stderr_target, 0);
+	log_set_print_filename2(osmo_stderr_target, LOG_FILENAME_NONE);

 	srand(time(NULL));

--- a/tests/lib/ippool_test.c
+++ b/tests/lib/ippool_test.c
@@ -131,7 +131,9 @@ int main(int argc, char **argv)
 	msgb_talloc_ctx_init(tall_ctx, 0);
 	osmo_init_logging2(tall_ctx, &log_info);
 	log_set_use_color(osmo_stderr_target, 0);
-	log_set_print_filename(osmo_stderr_target, 0);
+	log_set_print_filename2(osmo_stderr_target, LOG_FILENAME_NONE);
+	log_set_print_category(osmo_stderr_target, 0);
+	log_set_print_category_hex(osmo_stderr_target, 0);

 	srand(time(NULL));

--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -0,0 +1,3 @@
+bin_PROGRAMS = gtp-echo-responder
+
+gtp_echo_responder_SOURCES = gtp_echo_responder.c
--- a/utils/gtp_echo_responder.c
+++ b/utils/gtp_echo_responder.c
@@ -0,0 +1,470 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Pau Espin Pedrol <pespin@sysmocom.de>
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/* For more info see:
+ * 3GPP TS 29.060 (GTPv1 and GTPv0)
+ * 3GPP TS 29.274 (GTPv2C)
+ */
+
+#include "../config.h"
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <unistd.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <getopt.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/select.h>
+#include <sys/socket.h>
+
+#define GTP1C_PORT	2123
+#define GTP_MSGTYPE_ECHO_REQ	1
+#define GTP_MSGTYPE_ECHO_RSP	2
+#define GTP1C_IE_RECOVERY 14
+#define GTP2C_IE_RECOVERY 3
+#define GTP2C_IE_NODE_FEATURES 152
+
+struct gtp1_hdr {
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	uint8_t pn:1, s:1, e:1, spare:1, pt:1, version:3;
+#else
+	uint8_t version:3, pt:1, spare:1, e:1, s:1, pn:1;
+#endif
+	uint8_t type;
+	uint16_t length;
+	uint32_t tei;
+	uint16_t seq;
+	uint8_t npdu;
+	uint8_t next;
+} __attribute__((packed));
+
+struct gtp2_hdr {
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	uint8_t reserved:3, t:1, p:1, version:3;
+#else
+	uint8_t version:3, p:1, t:1, reserved:1;
+#endif
+	uint8_t type;
+	uint16_t length;
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	uint32_t reserved2:8, seq:24;
+#else
+	uint8_t seq:24, reserved2:1;
+#endif
+} __attribute__((packed));
+
+struct gtp_echo_resp_state {
+	struct {
+		char laddr[INET6_ADDRSTRLEN];
+		uint8_t recovery_ctr;
+		uint8_t node_features;
+	} cfg;
+	struct sockaddr_storage laddr_gtpc;
+	int fd_gtpc;
+};
+
+struct gtp_echo_resp_state *g_st;
+
+static void print_usage(void)
+{
+	printf("Usage: gtp-echo-responder [-h] [-V] [-l listen_addr]\n");
+}
+
+static void print_help(void)
+{
+	printf("  Some useful help...\n"
+	       "  -h --help		This help text\n"
+	       "  -V --version		Print the version of gtp-echo-responder\n"
+	       "  -l --listen-addr	Listend address for GTPCv1 and GTPCv2\n"
+	       "  -R --recovery-counter GTP Recovery Counter to transmit in GTP Echo Response message\n"
+	       "  -n --node-features	GTPCv2 Node Features bitmask to transmit in GTP Echo Response message\n"
+	       );
+}
+
+static void print_version(void)
+{
+	printf("gtp-echo-responder version %s\n", PACKAGE_VERSION);
+}
+
+static uint8_t parse_node_features_mask(const char *arg)
+{
+	unsigned long res;
+	char *end;
+	errno = 0;
+
+	res = strtoul(arg, &end, 0);
+	if ((errno == ERANGE && res == ULONG_MAX) || (errno && !res) ||
+	    arg == end || *end != '\0') {
+		fprintf(stderr, "Failed parsing Node Features bitmask: '%s'\n", arg);
+		exit(1);
+	}
+	if (res > 0xff) {
+		fprintf(stderr, "Failed parsing Node Features bitmask: '%s' > 0xFF\n", arg);
+		exit(1);
+	}
+	return (uint8_t)res;
+}
+static void handle_options(int argc, char **argv)
+{
+	while (1) {
+		int option_index = 0, c;
+		static struct option long_options[] = {
+			{ "help", 0, 0, 'h' },
+			{ "version", 0, 0, 'V' },
+			{ "listen-addr", 1, 0, 'l'},
+			{ "recovery-counter", 1, 0, 'R'},
+			{ "node-features", 1, 0, 'N'},
+			{ 0, 0, 0, 0 }
+		};
+
+		c = getopt_long(argc, argv, "hVl:R:N:", long_options, &option_index);
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'h':
+			print_usage();
+			print_help();
+			exit(0);
+		case 'V':
+			print_version();
+			exit(0);
+			break;
+		case 'l':
+			strncpy(&g_st->cfg.laddr[0], optarg, sizeof(g_st->cfg.laddr));
+			g_st->cfg.laddr[sizeof(g_st->cfg.laddr) - 1] = '\0';
+			break;
+		case 'R':
+			g_st->cfg.recovery_ctr = (uint8_t)atoi(optarg);
+			break;
+		case 'N':
+			g_st->cfg.node_features = parse_node_features_mask(optarg);
+			break;
+		}
+	}
+}
+
+static int init_socket(void)
+{
+	struct in_addr addr;
+	struct in6_addr addr6;
+	struct sockaddr_in *saddr;
+	struct sockaddr_in6 *saddr6;
+	int family;
+
+	if (inet_pton(AF_INET6, g_st->cfg.laddr, &addr6) == 1) {
+		family = AF_INET6;
+		saddr6 = (struct sockaddr_in6 *)&g_st->laddr_gtpc;
+		saddr6->sin6_family = family;
+		saddr6->sin6_port = htons(GTP1C_PORT);
+		memcpy(&saddr6->sin6_addr, &addr6, sizeof(addr6));
+	} else if (inet_pton(AF_INET, g_st->cfg.laddr, &addr) == 1) {
+		family = AF_INET;
+		saddr = (struct sockaddr_in *)&g_st->laddr_gtpc;
+		saddr->sin_family = family;
+		saddr->sin_port = htons(GTP1C_PORT);
+		memcpy(&saddr->sin_addr, &addr, sizeof(addr));
+	} else {
+		fprintf(stderr, "Failed parsing address %s\n", g_st->cfg.laddr);
+		return -1;
+	}
+
+	if ((g_st->fd_gtpc = socket(family, SOCK_DGRAM, 0)) < 0) {
+		fprintf(stderr, "socket() failed: %s\n", strerror(errno));
+		return -2;
+	}
+
+	if (bind(g_st->fd_gtpc, (struct sockaddr *)&g_st->laddr_gtpc, sizeof(g_st->laddr_gtpc)) < 0) {
+		fprintf(stderr, "bind() failed: %s\n", strerror(errno));
+		return -3;
+	}
+
+	return 0;
+}
+
+static const char *sockaddr2str(const struct sockaddr *saddr)
+{
+	static char _rem_addr_str[INET6_ADDRSTRLEN];
+	struct sockaddr_in *saddr4;
+	struct sockaddr_in6 *saddr6;
+
+	switch (saddr->sa_family) {
+	case AF_INET6:
+		saddr6 = (struct sockaddr_in6 *)saddr;
+		if (!inet_ntop(saddr6->sin6_family, &saddr6->sin6_addr, _rem_addr_str, sizeof(_rem_addr_str)))
+			strcpy(_rem_addr_str, "unknown");
+		return _rem_addr_str;
+	case AF_INET:
+		saddr4 = (struct sockaddr_in *)saddr;
+		if (!inet_ntop(saddr4->sin_family, &saddr4->sin_addr, _rem_addr_str, sizeof(_rem_addr_str)))
+			strcpy(_rem_addr_str, "unknown");
+		return _rem_addr_str;
+	default:
+		strcpy(_rem_addr_str, "unknown-family");
+		return _rem_addr_str;
+	}
+}
+
+static int write_cb(int fd, const uint8_t *buf, size_t buf_len, const struct sockaddr *rem_saddr)
+{
+	ssize_t rc;
+
+	rc = sendto(fd, buf, buf_len, 0, rem_saddr, sizeof(struct sockaddr_storage));
+	if (rc < 0) {
+		fprintf(stderr, "sendto() failed: %s\n", strerror(errno));
+		return -1;
+	}
+	if (rc != buf_len) {
+		fprintf(stderr, "sendto() short write: %zd vs exp %zu\n", rc, buf_len);
+		return -1;
+	}
+	return 0;
+}
+
+static int gen_gtpc1_echo_rsp(uint8_t *buf, struct gtp1_hdr *echo_req)
+{
+	int offset = 0;
+	struct gtp1_hdr *echo_rsp = (struct gtp1_hdr *)buf;
+	unsigned exp_hdr_len = (echo_req->s || echo_req->pn || echo_req->e) ? 12 : 8;
+
+	memcpy(echo_rsp, echo_req, exp_hdr_len);
+	echo_rsp->type = GTP_MSGTYPE_ECHO_RSP;
+	offset = exp_hdr_len;
+	buf[offset++] = GTP1C_IE_RECOVERY;
+	buf[offset++] = g_st->cfg.recovery_ctr;
+
+	/* Update Length */
+	echo_rsp->length = htons(offset - 8);
+	return offset;
+}
+
+static int gen_gtpc2_echo_rsp(uint8_t *buf, struct gtp2_hdr *echo_req)
+{
+	int offset = 0;
+	struct gtp1_hdr *echo_rsp = (struct gtp1_hdr *)buf;
+	unsigned exp_hdr_len = 8;
+
+	memcpy(echo_rsp, echo_req, exp_hdr_len);
+	echo_rsp->type = GTP_MSGTYPE_ECHO_RSP;
+	offset = exp_hdr_len;
+
+	/* 3GPP TS 29.274 sec 8.5 Recovery (Restart Counter) */
+	buf[offset++] = GTP2C_IE_RECOVERY;
+	buf[offset++] = 0; /* IE Length (high) */
+	buf[offset++] = 1; /* IE Length (low) */
+	buf[offset++] = 0; /* Spare=0 | Instance=0 (Table 7.1.1-1) */
+	buf[offset++] = g_st->cfg.recovery_ctr;
+
+	/* 3GPP TS 29.274 sec 8.83 Node Features */
+	if (g_st->cfg.node_features > 0) {
+		buf[offset++] = GTP2C_IE_NODE_FEATURES;
+		buf[offset++] = 0; /* IE Length (high) */
+		buf[offset++] = 1; /* IE Length (low) */
+		buf[offset++] = 0; /* Spare=0 | Instance=0 (Table 7.1.1-1) */
+		buf[offset++] = g_st->cfg.node_features;
+	}
+
+	/* Update Length */
+	echo_rsp->length = htons(offset - 4);
+	return offset;
+}
+
+static int rx_gtpc1_echo_req(struct gtp1_hdr *echo_req, unsigned buf_len, const struct sockaddr *rem_saddr)
+{
+	int rc;
+	const size_t tx_buf_len = buf_len + 128; /* Leave some extra room */
+	uint8_t *tx_buf = alloca(tx_buf_len);
+
+	printf("Rx GTPCv1_ECHO_REQ from %s, Tx GTPCv1_ECHO_RSP\n", sockaddr2str(rem_saddr));
+
+	memset(tx_buf, 0, tx_buf_len);
+	rc = gen_gtpc1_echo_rsp(tx_buf, echo_req);
+	return write_cb(g_st->fd_gtpc, tx_buf, rc, rem_saddr);
+}
+
+static int rx_gtpc1(struct gtp1_hdr *hdr, unsigned buf_len, const struct sockaddr *rem_saddr)
+{
+	unsigned exp_hdr_len = (hdr->s || hdr->pn || hdr->e) ? 12 : 8;
+	unsigned pdu_len;
+
+	if (buf_len < exp_hdr_len) {
+		fprintf(stderr, "GTPCv1 packet size smaller than header! %u < exp %u\n", buf_len, exp_hdr_len);
+		return -1;
+	}
+
+	pdu_len = ntohs(hdr->length);
+	if (buf_len < 8 + pdu_len) {
+		fprintf(stderr, "GTPCv1 packet size smaller than announced! %u < exp %u\n", buf_len, 8 + pdu_len);
+		return -1;
+	}
+
+	if (hdr->pt != 1) {
+		fprintf(stderr, "GTPCv1 Protocol Type GTP' not supported!\n");
+		return -1;
+	}
+
+	switch (hdr->type) {
+	case GTP_MSGTYPE_ECHO_REQ:
+		return rx_gtpc1_echo_req(hdr, buf_len, rem_saddr);
+	default:
+		fprintf(stderr, "Silently ignoring unexpected packet of type %u\n", hdr->type);
+		return 0;
+	}
+}
+
+static int rx_gtpc2_echo_req(struct gtp2_hdr *echo_req, unsigned buf_len, const struct sockaddr *rem_saddr)
+{
+	int rc;
+	const size_t tx_buf_len = buf_len + 128; /* Leave some extra room */
+	uint8_t *tx_buf = alloca(tx_buf_len);
+
+	if (echo_req->t) {
+		fprintf(stderr, "GTPCv2 ECHO message should contain T=0!\n");
+		return -1;
+	}
+
+	printf("Rx GTPCv2_ECHO_REQ from %s, Tx GTPCv2_ECHO_RSP\n", sockaddr2str(rem_saddr));
+
+	memset(tx_buf, 0, tx_buf_len);
+	rc = gen_gtpc2_echo_rsp(tx_buf, echo_req);
+	return write_cb(g_st->fd_gtpc, tx_buf, rc, rem_saddr);
+}
+
+static int rx_gtpc2(struct gtp2_hdr *hdr, unsigned buf_len, const struct sockaddr *rem_saddr)
+{
+	unsigned exp_hdr_len = hdr->t ? 12 : 8;
+	unsigned pdu_len;
+
+	if (hdr->p) {
+		fprintf(stderr, "GTPCv2 piggybacked message not supported!\n");
+		return -1;
+	}
+
+	if (buf_len < exp_hdr_len) {
+		fprintf(stderr, "GTPCv2 packet size smaller than header! %u < exp %u\n", buf_len, exp_hdr_len);
+		return -1;
+	}
+
+	pdu_len = ntohs(hdr->length);
+	/* 3GPP TS 29.274 sec 5.5.1: "Octets 3 to 4 represent the Message Length
+	 * field. This field shall indicate the length of the message in octets
+	 * excluding the mandatory part of the GTP-C header (the first 4
+	 * octets). The TEID (if present) and the Sequence  Number shall be
+	 * included in the length count" */
+	if (buf_len < 4 + pdu_len) {
+		fprintf(stderr, "GTPCv2 packet size smaller than announced! %u < exp %u\n", buf_len, 4 + pdu_len);
+		return -1;
+	}
+
+	switch (hdr->type) {
+	case GTP_MSGTYPE_ECHO_REQ:
+		return rx_gtpc2_echo_req(hdr, buf_len, rem_saddr);
+	default:
+		fprintf(stderr, "Silently ignoring unexpected packet of type %u\n", hdr->type);
+		return 0;
+	}
+}
+
+static int read_cb(int fd)
+{
+	ssize_t sz;
+	uint8_t buf[4096];
+	struct sockaddr_storage rem_saddr;
+	socklen_t rem_saddr_len = sizeof(rem_saddr);
+	struct gtp1_hdr *hdr1;
+
+	if ((sz = recvfrom(fd, buf, sizeof(buf), 0, (struct sockaddr *)&rem_saddr, &rem_saddr_len)) < 0) {
+		fprintf(stderr, "recvfrom() failed: %s\n", strerror(errno));
+		return -1;
+	}
+	if (sz == 0) {
+		fprintf(stderr, "recvfrom() read zero bytes!\n");
+		return -1;
+	}
+
+	hdr1 = (struct gtp1_hdr *)&buf[0];
+	switch (hdr1->version) {
+	case 1:
+		return rx_gtpc1(hdr1, sz, (const struct sockaddr *)&rem_saddr);
+	case 2:
+		return rx_gtpc2((struct gtp2_hdr *)&buf[0], sz, (const struct sockaddr *)&rem_saddr);
+	default:
+		fprintf(stderr, "Rx GTPv%u: not supported (flags=0x%x)\n", hdr1->version, buf[0]);
+		return -1;
+	}
+}
+
+static int loop(void)
+{
+	int rc;
+	fd_set rfds;
+	int nfds;
+
+	while (true) {
+		FD_ZERO(&rfds);
+		FD_SET(g_st->fd_gtpc, &rfds);
+		nfds = g_st->fd_gtpc + 1;
+		rc = select(nfds, &rfds, NULL, NULL, NULL);
+		if (rc == 0)
+			continue;
+		if (rc < 0) {
+			fprintf(stderr, "select() failed: %s\n", strerror(errno));
+			return -1;
+		}
+
+		if (FD_ISSET(g_st->fd_gtpc, &rfds))
+			read_cb(g_st->fd_gtpc);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	g_st = calloc(1, sizeof(struct gtp_echo_resp_state));
+
+	strcpy(g_st->cfg.laddr, "::");
+
+	handle_options(argc, argv);
+
+	printf("Listening on: %s\n", g_st->cfg.laddr);
+
+	if (init_socket() < 0)
+		exit(1);
+
+	printf("Socket bound successfully, listening for requests...\n");
+
+	if (loop() < 0)
+		exit(1);
+
+	return 0;
+}
--- a/utils/gtp_echo_responder_test.py
+++ b/utils/gtp_echo_responder_test.py
@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+# MIT License
+#
+# Copyright (c) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+# Author: Pau Espin Pedrol <pespin@sysmocom.de>
+#
+# SPDX-License-Identifier: MIT
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice (including the next
+# paragraph) shall be included in all copies or substantial portions of the
+# Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+
+import socket
+import argparse
+import struct
+from ipaddress import ip_address, IPv4Address
+
+GTP1C_PORT = 2123
+BUF_SIZE = 4096
+
+GTP_HDRv1_FLAG_PN = (1<<0)
+GTP_HDRv1_FLAG_S = (1<<1)
+GTP_HDRv1_FLAG_E = (1<<2)
+GTP_HDRv1_PT_GTP = (1<<4)
+GTP_HDRv1_VER_GTP1 = (1<<5)
+
+GTP_HDRv2_FLAG_T = (1<<3)
+GTP_HDRv2_FLAG_P = (1<<4)
+GTP_HDRv2_VER_GTP2 = (2<<5)
+
+def gen_gtpc_v1_hdr(flags, type, length, tei, seq=0, npdu=0, next=0):
+    spare = 0
+    if (flags & (GTP_HDRv1_FLAG_PN|GTP_HDRv1_FLAG_S|GTP_HDRv1_FLAG_E)):
+        #long format
+        length += 4
+        d = struct.pack('!BBHIHBB', flags, type, length, tei, seq, npdu, next)
+    else:
+        #short format
+        d = struct.pack('!BBHI', flags, type, length, tei)
+    return d
+
+def gen_gtpc_v2_hdr(flags, type, length, tei=0, seq=0):
+    spare = 0
+    if (flags & (GTP_HDRv2_FLAG_T)):
+        #long format, with TEI
+        length += 4 + 4
+        d = struct.pack('!BBHIHBB', flags, type, length, tei, seq >> 8, seq & 0xff, spare)
+    else:
+        #short format
+        length += 4
+        d = struct.pack('!BBHHBB', flags, type, length, seq >> 8, seq & 0xff, spare)
+    return d
+
+def gen_gtpc_v1_echo_req(tei=0, append_flags=0, seq=0, npdu=0, next=0):
+    return gen_gtpc_v1_hdr(GTP_HDRv1_VER_GTP1 | GTP_HDRv1_PT_GTP | append_flags, 1, 0, tei, seq, npdu, next)
+
+def gen_gtpc_v2_echo_req(append_flags=0, seq=0, recovery=0, node_features=-1):
+    length = 0
+    payload = b''
+    if (recovery > 0):
+        recovery_ie = struct.pack('!BHBB', 3, 1, 0, recovery)
+        payload += recovery_ie
+        length += len(recovery_ie)
+    if (node_features > 0):
+        node_features_ie = struct.pack('!BHBB', 152, 1, 0, node_features)
+        payload += node_features_ie
+        length += len(node_features_ie)
+    return gen_gtpc_v2_hdr(GTP_HDRv2_VER_GTP2 | append_flags, 1, length, 0, seq) + payload
+
+def tx_rx(sk, rem_addr, tx_buf, exp_rx = True):
+    print('Tx ECHO_REQ to %r: %r' % (repr(rem_addr), repr(tx_buf)))
+    sk.sendto(tx_buf, rem_addr)
+    if exp_rx:
+        rx_buf = sk.recvfrom(BUF_SIZE)
+        msg = "Message from Server {}".format(rx_buf)
+        print(msg)
+
+if __name__ == '__main__':
+    p = argparse.ArgumentParser(description='Tester for gtp-echo-recorder.')
+    p.add_argument('-l', '--local-address', default='127.0.0.2', help="Local GTP address")
+    p.add_argument('-r', '--remote-address', default='127.0.0.1', help="Remote GTP address")
+    args = p.parse_args()
+
+    print('Binding socket on %r...' % repr((args.local_address, GTP1C_PORT)))
+    family = socket.AF_INET if type(ip_address(args.local_address)) is IPv4Address else socket.AF_INET6
+    sk = socket.socket(family=family, type=socket.SOCK_DGRAM)
+    sk.bind((args.local_address, GTP1C_PORT));
+
+    rem_addr = (args.remote_address, GTP1C_PORT)
+
+    tx_rx(sk, rem_addr, gen_gtpc_v1_echo_req())
+    tx_rx(sk, rem_addr, gen_gtpc_v1_echo_req(1, GTP_HDRv1_FLAG_S, seq=67))
+    tx_rx(sk, rem_addr, gen_gtpc_v2_echo_req(0, seq=300, recovery=-1, node_features=-1))
+    tx_rx(sk, rem_addr, gen_gtpc_v2_echo_req(0, seq=20, recovery=99, node_features=-1))
+    tx_rx(sk, rem_addr, gen_gtpc_v2_echo_req(0, seq=20, recovery=100, node_features=0xbb))