diff --git a/ggsn/ggsn.c b/ggsn/ggsn.c
new file mode 100644
index 0000000..a850de8
--- /dev/null
+++ b/ggsn/ggsn.c
@@ -0,0 +1,424 @@
+/* 
+ *  OpenGGSN - 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.
+ * 
+ *  The initial developer of the original code is
+ *  Jens Jakobsen <jj@openggsn.org>
+ * 
+ *  Contributor(s):
+ * 
+ */
+
+/* ggsn.c
+ *
+ */
+
+#ifdef __linux__
+#define _GNU_SOURCE 1		/* strdup() prototype, broken arpa/inet.h */
+#endif
+
+
+#include <syslog.h>
+#include <ctype.h>
+#include <netdb.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <sys/socket.h>  
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <features.h>
+
+#include <errno.h>
+
+#include <asm/types.h>
+#include <sys/socket.h>
+#include <linux/netlink.h> 
+
+#include <time.h>
+
+#include "tun.h"
+#include "../gtp/pdp.h"
+#include "../gtp/gtp.h"
+#include "cmdline.h"
+
+
+int maxfd = 0;	                /* For select() */
+int tun_fd = -1;		/* Network file descriptor */
+struct tun_t *tun;              /* TUN instance            */
+struct in_addr net, mask;       /* Network interface       */
+int debug;                      /* Print debug output */
+
+
+/* Used to write process ID to file. Assume someone else will delete */
+void log_pid(char *pidfile) {
+  FILE *file;
+  mode_t oldmask;
+  
+  oldmask = umask(022);
+  file = fopen(pidfile, "w");
+  umask(oldmask);
+  if(!file)
+    return;
+  fprintf(file, "%d\n", getpid());
+  fclose(file);
+}
+
+
+int encaps_printf(void *p, void *packet, unsigned len)
+{
+  int i;
+  if (debug) {
+    printf("The packet looks like this:\n");
+    for( i=0; i<len; i++) {
+      printf("%02x ", (unsigned char)*(char *)(packet+i));
+      if (!((i+1)%16)) printf("\n");
+    };
+    printf("\n"); 
+  }
+  return 0;
+}
+
+int getip(struct pdp_t *pdp, void* ipif, struct ul66_t *eua,
+	  struct in_addr *net, struct in_addr *mask) {
+  struct in_addr addr;
+  uint32_t ip_start, ip_end, ip_cur;
+  struct pdp_t *pdp_;
+  struct ul66_t eua_;
+
+  if (debug) {
+  printf("Begin getip %d %d %2x%2x%2x%2x\n", (unsigned)ipif, eua->l, 
+	 eua->v[2],eua->v[3],eua->v[4],eua->v[5]);
+  }
+
+  ip_start = ntoh32(net->s_addr & mask->s_addr);
+  ip_end   = ntoh32(hton32(ip_start) | ~mask->s_addr);
+
+  /* By convention the first address is the network address, and the last */
+  /* address is the broadcast address. This way two IP addresses are "lost" */
+  ip_start++; 
+  
+  if (eua->l == 0) { /* No address supplied. Find one that is available! */
+    /* This routine does linear search. In order to support millions of 
+     * addresses we should instead keep a linked list of available adresses */
+    for (ip_cur = ip_start; ip_cur < ip_end; ip_cur++) {
+      addr.s_addr = hton32(ip_cur);
+      pdp_ntoeua(&addr, &eua_);
+      if (pdp_ipget(&pdp_, ipif, &eua_) == -1) {
+	pdp_ntoeua(&addr, &pdp->eua);
+	pdp->ipif = ipif;
+	return 0;
+      };
+    }
+    return EOF; /* No addresses available */
+  }
+  else { /* Address supplied */
+    if (pdp_ipget(&pdp_, ipif, eua) == -1) {
+      pdp->ipif = ipif;
+      pdp->eua.l = eua->l;
+      memcpy(pdp->eua.v, eua->v, eua->l);
+      return 0;
+    }
+    else return EOF; /* Specified address not available */
+  }
+}
+
+
+int delete_context(struct pdp_t *pdp) {
+  pdp_ipdel(pdp);
+  return 0;
+}
+
+
+
+int create_context(struct pdp_t *pdp) {
+
+  if (debug) printf("Received create PDP context request\n");
+
+  pdp->eua.l=0; /* TODO: Indicates dynamic IP */
+
+  /* ulcpy(&pdp->qos_neg, &pdp->qos_req, sizeof(pdp->qos_req.v)); */
+  memcpy(pdp->qos_neg0, pdp->qos_req0, sizeof(pdp->qos_neg));
+
+  getip(pdp, tun, &pdp->eua, &net, &mask);
+  pdp_ipset(pdp, pdp->ipif, &pdp->eua);
+
+  return 0; /* Success */
+}
+
+
+
+int create_tun() {
+  char buf[1024];
+  char snet[100], smask[100];
+
+  if ((tun_fd = tun_newtun((struct tun_t**) &tun)) > maxfd)
+    maxfd = tun_fd;
+
+  if (tun_fd == -1) {
+    printf("Failed to open tun\n");
+    exit(1);
+  }
+
+  strncpy(snet, inet_ntoa(net), 100);
+  strncpy(smask, inet_ntoa(mask), 100);
+
+  sprintf(buf, "ifconfig %s %s mtu 1450 netmask %s",
+	  tun->devname, snet, smask);
+  if (debug) printf("%s\n", buf);
+  system(buf);
+
+  system("echo 1 > /proc/sys/net/ipv4/ip_forward");
+  
+  return 0;
+}
+
+
+int encaps_gtp(void *gsn, struct tun_t *tun, void *pack, unsigned len) {
+  struct pdp_t *pdp;
+  struct in_addr addr;
+  struct ul66_t eua;
+  /*printf("encaps_gtp. Packet received: forwarding to gtp.\n");*/
+  /* First we need to extract the IP destination address */
+  memcpy(&addr.s_addr, pack+16, 4); /* This ought to be dest addr */
+  pdp_ntoeua(&addr, &eua);
+  if (pdp_ipget(&pdp, tun, &eua) == 0) {
+    return gtp_gpdu((struct gsn_t*) gsn, pdp, pack, len);
+  }
+  else {
+    if (debug) printf("Received packet with no destination!!!\n");
+    return 0;
+  }
+}
+
+
+int encaps_tun(struct pdp_t *pdp, void *pack, unsigned len) {
+  /*  printf("encaps_tun. Packet received: forwarding to tun\n");*/
+  return tun_encaps((struct tun_t*) pdp->ipif, pack, len);
+}
+
+
+int main(int argc, char **argv)
+{
+  /* gengeopt declarations */
+  struct gengetopt_args_info args_info;
+
+  struct hostent *host;
+
+  struct in_addr listen;
+	
+  int gtpfd = -1;		/* Network file descriptor */
+  struct gsn_t *gsn;            /* GSN instance            */
+
+  fd_set fds;			/* For select() */
+  struct timeval idleTime;	/* How long to select() */
+  int i;                          /* for loop */
+
+  struct ul_t qos, apn;
+  unsigned char qosh[3], apnh[256];
+
+  int timelimit; /* Number of seconds to be connected */
+  int starttime; /* Time program was started */
+
+  /* open a connection to the syslog daemon */
+  /*openlog(PACKAGE, LOG_PID, LOG_DAEMON);*/
+  openlog(PACKAGE, (LOG_PID | LOG_PERROR), LOG_DAEMON);
+
+  if (cmdline_parser (argc, argv, &args_info) != 0)
+    exit(1);
+  if (args_info.debug_flag) {
+    printf("listen: %s\n", args_info.listen_arg);
+    printf("conf: %s\n", args_info.conf_arg);
+    printf("fg: %d\n", args_info.fg_flag);
+    printf("debug: %d\n", args_info.debug_flag);
+    printf("qos: %#08x\n", args_info.qos_arg);
+    printf("apn: %s\n", args_info.apn_arg);
+    printf("net: %s\n", args_info.net_arg);
+    printf("mask: %s\n", args_info.mask_arg);
+    printf("pidfile: %s\n", args_info.pidfile_arg);
+    printf("statedir: %s\n", args_info.statedir_arg);
+    printf("timelimit: %d\n", args_info.timelimit_arg);
+  }
+
+  /* Try out our new parser */
+  
+  if (cmdline_parser_configfile (args_info.conf_arg, &args_info, 0) != 0)
+    exit(1);
+  if (args_info.debug_flag) {
+    printf("cmdline_parser_configfile\n");
+    printf("listen: %s\n", args_info.listen_arg);
+    printf("conf: %s\n", args_info.conf_arg);
+    printf("fg: %d\n", args_info.fg_flag);
+    printf("debug: %d\n", args_info.debug_flag);
+    printf("qos: %#08x\n", args_info.qos_arg);
+    printf("apn: %s\n", args_info.apn_arg);
+    printf("net: %s\n", args_info.net_arg);
+    printf("mask: %s\n", args_info.mask_arg);
+    printf("pidfile: %s\n", args_info.pidfile_arg);
+    printf("statedir: %s\n", args_info.statedir_arg);
+    printf("timelimit: %d\n", args_info.timelimit_arg);
+  }
+
+  /* Handle each option */
+
+  /* foreground                                                   */
+  /* If flag not given run as a daemon                            */
+  if (!args_info.fg_flag)
+    {
+      closelog(); 
+      /* Close the standard file descriptors. */
+      /* Is this really needed ? */
+      freopen("/dev/null", "w", stdout);
+      freopen("/dev/null", "w", stderr);
+      freopen("/dev/null", "r", stdin);
+      daemon(0, 0);
+      /* Open log again. This time with new pid */
+      openlog(PACKAGE, LOG_PID, LOG_DAEMON);
+    }
+
+  /* debug                                                        */
+  debug = args_info.debug_flag;
+
+  /* pidfile */
+  /* This has to be done after we have our final pid */
+  if (args_info.pidfile_arg) {
+    log_pid(args_info.pidfile_arg);
+  }
+
+  /* listen                                                       */
+  /* If no listen option is specified listen to any local port    */
+  /* Do hostname lookup to translate hostname to IP address       */
+  if (args_info.listen_arg) {
+    if (!(host = gethostbyname(args_info.listen_arg))) {
+      fprintf(stderr, "%s: Invalid listening address: %s!\n", 
+	      PACKAGE, args_info.listen_arg);
+      syslog(LOG_ERR, "Invalid listening address: %s!", 
+	     args_info.listen_arg);
+      return 1;
+    }
+    else {
+      memcpy(&listen.s_addr, host->h_addr, host->h_length);
+    }
+  }
+  else {
+    listen.s_addr = htonl(INADDR_ANY);
+  }
+  
+  /* net                                                          */
+  /* Store net as in_addr                                         */
+  if (args_info.net_arg) {
+    if (!inet_aton(args_info.net_arg, &net)) {
+      fprintf(stderr, "%s: Invalid network address: %s!\n", 
+	      PACKAGE, args_info.net_arg);
+      syslog(LOG_ERR, "Invalid network address: %s!", 
+	     args_info.net_arg);
+      return 1;
+    }
+  }
+
+  /* mask                                                         */
+  /* Store mask as in_addr                                        */
+  if (args_info.mask_arg) {
+    if (!inet_aton(args_info.mask_arg, &mask)) {
+      fprintf(stderr, "%s: Invalid network mask: %s!\n", 
+	      PACKAGE, args_info.mask_arg);
+      syslog(LOG_ERR, "Invalid network mask: %s!", 
+	     args_info.mask_arg);
+      return 1;
+    }
+  }
+
+  /* Timelimit                                                       */
+  timelimit = args_info.timelimit_arg;
+  starttime = time(NULL);
+  
+  /* qos                                                             */
+  qos.l = 3;
+  qos.v = qosh;
+  qos.v[2] = (args_info.qos_arg) & 0xff;
+  qos.v[1] = ((args_info.qos_arg) >> 8) & 0xff;
+  qos.v[0] = ((args_info.qos_arg) >> 16) & 0xff;
+  
+  /* apn                                                             */
+  if (strlen(args_info.apn_arg)>255) {
+    printf("invalid APN\n");
+    exit(1);
+  }
+  apn.l = strlen(args_info.apn_arg) + 1;
+  apn.v = apnh;
+  apn.v[0] = (char) strlen(args_info.apn_arg);
+  strncpy(&apn.v[1], args_info.apn_arg, 255);
+
+  if (debug) printf("gtpclient: Initialising GTP tunnel\n");
+  
+  if ((gtpfd = gtp_new(&gsn, args_info.statedir_arg, &listen)) > maxfd)
+    maxfd = gtpfd;
+
+  if ((gtpfd = gtp_fd(gsn)) > maxfd)
+    maxfd = gtpfd;
+    
+
+  gtp_set_cb_gpdu(gsn, encaps_tun);
+  gtp_set_cb_delete_context(gsn, delete_context);
+  
+  gtp_set_cb_create_context(gsn, create_context);
+  create_tun();
+
+  /******************************************************************/
+  /* Main select loop                                               */
+  /******************************************************************/
+
+  while (((starttime + timelimit) > time(NULL)) || (0 == timelimit)) {
+	
+    FD_ZERO(&fds);
+    if (tun_fd != -1) FD_SET(tun_fd, &fds);
+    if (gtpfd != -1) FD_SET(gtpfd, &fds);
+    
+    gtp_retranstimeout(gsn, &idleTime);
+    switch (select(maxfd + 1, &fds, NULL, NULL, &idleTime)) {
+    case -1:	/* Error with select() *
+		   if (errno != EINTR)
+		   syslog(LOG_ERR, "CTRL: Error with select(), quitting");
+		   *goto leave_clear_call;*/
+      syslog(LOG_ERR, "GGSN: select = -1");
+      break;  
+    case 0:
+      gtp_retrans(gsn); /* Only retransmit if nothing else */
+      break; 
+    default:
+      break;
+    }
+
+    if (tun_fd != -1 && FD_ISSET(tun_fd, &fds) && 
+	tun_decaps(tun, encaps_gtp, gsn) < 0) {
+      syslog(LOG_ERR, "TUN read failed (fd)=(%d)", tun_fd);
+    }
+
+    if (gtpfd != -1 && FD_ISSET(gtpfd, &fds) && 
+	gtp_decaps(gsn) < 0) {
+      syslog(LOG_ERR, "GTP read failed (gre)=(%d)", gtpfd);
+    }
+    
+    
+    }
+
+  gtp_free(gsn);
+  
+  return 1;
+  
+}
+