*** QuickStart *** REQUIREMENTS Linux OpenGGSN was developed and tested using Redhat 7.1 and Redhat 7.2. It should run also on other Linux distributions as well as FreeBSD and Solaris, but this is untested. Please tell me of any testing results. Tun Both ggsn and sgsnemu uses the tun package. You need at least tun version 1.1. See http://vtun.sourceforge.net/tun/ for instructions on installation. Tun is included in the kernel from early version 2.4, so you will not normally need to install it. For Redhat 7.1, 7.2 and 8.0 you do however need to do the following: mkdir /dev/net mknod /dev/net/tun c 10 200 Add this line to /etc/modules.conf: alias char-major-10-200 tun depmod -a COMPILATION and INSTALLATION 1 ./configure 2 cd gtp 3 make 4 make install 5 cd .. 6 make 7 make install 8 Add /usr/local/lib to /etc/ld.so.conf 9 Run ldconfig You need to be root in order to install the package, but not in order to compile. Steps 2 to 5 are only needed the first time you install the package. Most likely steps 8 and 9 can be omitted as the path to libgtp is now included in Makefile.am for sgsnemu and ggsn. RUNNING sgsnemu Edit the configuration file sgsnemu.conf found under openggsn/examples. Use sgsnemu -h for a list of available options. Start the emulator as root using the command: sgsnemu -c examples/sgsnemu.conf -l 10.20.30.50 -r 10.20.30.40 This will cause the sgsn emulator to bind to local address 10.20.30.50 and connect to the ggsn found at 10.20.30.40. 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. ggsn Edit the configuration file ggsn.conf found under openggsn/examples. Use sgsnemu -h for a list of available options. Start the ggsn as root using the command: ggsn --fg -c examples/ggsn.conf -l 10.20.30.40 --statedir . This will run the ggsn in foreground using the local interface 10.20.30.40. Of cause you can use sgsnemu to test the GGSN. SUPPORT If you have any questions drop me a line at jj@openggsn.org. *** Features *** OpenGGSN is an open source implementation of GPRS Support Nodes (GSNs). It implements the GPRS tunneling protocol (GTP) version 0. OpenGGSN provides 3 components: * gtplib * ggsn * sgsnemu gtplib This library contains all functionality relating to the GTP protocol. Use this libraty if you want to implement your own GSN. Currently gtplib supports GTPv0. At the moment no interface documentation is available for download. ggsn The ggsn implements a Gateway GPRS Support Node. The GGSN is a small application which is provided in order to test and demonstrate the use of gtplib. It is fully compliant to the 3GPP standards, but lacks important functionality such as charging and management. Use this application as a starting point if you want to build your own GGSN with your own fancy VPN, management and charging functionality. sgsnemu This application emulates a Serving GPRS Support Node (SGSN). sgsnemu enables you to test your 3GPP core network without the need to invest in a 3G radio access network. An important application of sgsnemu is the testing of roaming connectivity through a GPRS roaming exchange. *** Required software *** TUN (http://vtun.sourceforge.net/tun/) Both ggsn and sgsnemu uses the tun package. You need at least tun version 1.1. See the above web page for instructions on installation. Tun is included in the kernel from early version 2.4, so you will not normally need to install it. For Redhat 7.1, 7.2 and 8.0 you do however need to do the following: mkdir /dev/net mknod /dev/net/tun c 10 200 Add the following line to /etc/modules.conf: alias char-major-10-200 tun depmod -a GENGETOPT (http://www.gnu.org/software/gengetopt/gengetopt.html) Gengetopt is required if you want to change the options defined in the 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 ggsn do the following: cd ggsn gengetopt < cmdline.ggo --conf-parser To use gengetopt for the sgsnemu do the following: cd sgsnemu gengetopt < cmdline.ggo --conf-parser *** Compilation and Installation *** SETTING UP AUTOTOOLS You do not need to perform this step if you are only going to compile the package: 0 Get version from somewhere: Script to extract version from configure.ac 1 Copy the latest config.guess and config.sub from ftp://ftp.gnu.org/gnu/config 2 Run autoscan and copy configure.scan to configure.ac 3 Add/edit the following lines in configure.ac: AC_INIT(openggsn, 0.52, jj@openggsn.org) AC_CONFIG_SRCDIR([gtp/gtp.c]) AM_CONFIG_HEADER([config.h]) AC_PROG_LIBTOOL AM_PROG_LIBTOOL AM_INIT_AUTOMAKE() 4 libtoolize --automake --copy (ads copy of ltmain.sh) 5 aclocal 6 autoheader 7 automake --add-missing (Ads link to missing, install-sh, depcomp) 8 automake 9 autoconf The above will initialise the project to the current version of autotools (As installed in RedHat 8.0). See http://sources.redhat.com/autobook/autobook/autobook_25.html#SEC25 for details on autotools. COMPILATION AND INSTALLATION 1 ./configure 2 make clean 3 cd gtp 4 make 5 make install (as root) 6 cd .. (Step 3 to 6 you only need to run the first time to install libgtp) 7 make 8 make install (as root) 9 Add /usr/local/lib to /etc/ld.so.conf 10 run ldconfig (Step 9 and 10 are not required as path to libgtp is included in Makefile) *** Running ggsn *** Use 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/ggsn.conf for the format of this file. *** Running sgsnemu *** 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. If you want to test a GRX roaming connection you will need to do the following: 1) Install sgsnemu on a Linux Box. See under installation above. 2) Connect your Linux box with sgsnemu installed to the GPRS core network. Use the same LAN switch as the one your SGSN is connected to. You also need a free IP address that can be used by sgsnemu. 3) You need to configure networking in terms of interface address, subnet mask and default route. See the Linux Networking HOWTO for details. 4) Launch sgsnemu with something like: sgsnemu --fg --listen 10.20.30.50 --remote 10.20.30.40 --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: 10.20.30.50 (10.20.30.50) Remote IP address is: 10.20.30.40 (10.20.30.40) IMSI is: 240011234567890 (0x98765432110042) Using APN: internet Using MSISDN: 46702123456 Initialising GTP library OpenGGSN[1823]: GTP: gtp_newgsn() started Done initialising GTP library Sending off echo request 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 you did not get an echo response it means that something is wrong either with your setup OR with the GRX connection OR with your roaming partners connection. If the above went well you might want to try to establish a PDP context to the remote GGSN. Note that you should be carefull when establishing PDP contexts using sgsnemu as each established PDP context will result in a Charge Detail Record (CDR) being generated by the GGSN. You should use real IMSI and MSISDN from a valid test SIM card. Otherwise some poor customer might get charged for your testing. Also note that you are establishing a connection to the Gi netowrk, so please be carefull not to route internet traffic onto the GPRS core network! Assuming you know what you are doing: sgsnemu --fg --listen 10.20.30.50 --remote 10.20.30.40 --dns 10.20.38.51 --timelimit 10 --contexts 1 --apn internet --imsi 240011234567890 --msisdn 46702123456 --net 192.168.0.0 --mask 255.255.255.0 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: 10.20.30.50 (10.20.30.50) Remote IP address is: 10.20.30.40 (10.20.30.40) IMSI is: 240011234567890 (0x98765432110042) Using APN: internet Using MSISDN: 46702123456 Initialising GTP library OpenGGSN[1838]: GTP: gtp_newgsn() started Done initialising GTP library Sending off echo request Setting up PDP context #0 Waiting for response from ggsn........ Received echo response. Cause value: 0 Received create PDP context response. Cause value: 128 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. If you specified the correct --net and --mask you should be able to ping a known address on the Gi network of the roaming partner. You should even be able to do web browsing through the PDP context. Note however that you probably need to adjust your routing tables, so that you make sure that all GRX traffic is routed to the GPRS core network and everything else through the PDP context. The proper way to 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. 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