release/src/router/rp-l2tp/network.c

   1 /***********************************************************************
   2 *
   3 * network.c
   4 *
   5 * Code for handling the UDP socket we send/receive on.  All of our
   6 * tunnels use a single UDP socket which stays open for the life of
   7 * the application.
   8 *
   9 * Copyright (C) 2002 by Roaring Penguin Software Inc.
  10 *
  11 * This software may be distributed under the terms of the GNU General
  12 * Public License, Version 2, or (at your option) any later version.
  13 *
  14 * LIC: GPL
  15 *
  16 ***********************************************************************/
  17
  18 static char const RCSID[] =
  19 "$Id: network.c,v 1.1.48.1 2005/08/08 12:05:25 honor Exp $";
  20
  21 #include "l2tp.h"
  22 #include "event.h"
  23 #include <sys/socket.h>
  24 #include <netinet/in.h>
  25 #include <errno.h>
  26 #include <fcntl.h>
  27 #include <string.h>
  28 #include <signal.h>
  29 #include <stdio.h>
  30
  31 /* Our socket */
  32 int Sock = -1;
  33
  34 static EventHandler *NetworkReadHandler = NULL;
  35 static void network_readable(EventSelector *es,
  36                              int fd,
  37                              unsigned int flags,
  38                              void *data);
  39 //char Hostname[MAX_HOSTNAME]; //2005-04-14 by kanki
  40
  41 static void
  42 sigint_handler(int sig)
  43 {
  44     static int count = 0;
  45
  46     count++;
  47     fprintf(stderr, "In sigint handler: %d\n", count);
  48     if (count < 5) {
  49         l2tp_cleanup();
  50     }
  51     exit(1);
  52 }
  53
  54 /**********************************************************************
  55 * %FUNCTION: network_init
  56 * %ARGUMENTS:
  57 *  es -- an event selector
  58 * %RETURNS:
  59 *  >= 0 if all is OK, <0 if not
  60 * %DESCRIPTION:
  61 *  Initializes network; opens socket on UDP port 1701; sets up
  62 *  event handler for incoming packets.
  63 ***********************************************************************/
  64 int
  65 l2tp_network_init(EventSelector *es)
  66 {
  67     struct sockaddr_in me;
  68     int flags;
  69
  70     //gethostname(Hostname, sizeof(Hostname)); //2005-04-14 by kanki
  71     //Hostname[sizeof(Hostname)-1] = 0;
  72
  73     Event_HandleSignal(es, SIGINT, sigint_handler);
  74     if (Sock >= 0) {
  75         if (NetworkReadHandler) {
  76             Event_DelHandler(es, NetworkReadHandler);
  77             NetworkReadHandler = NULL;
  78         }
  79         close(Sock);
  80         Sock = -1;
  81     }
  82     Sock = socket(PF_INET, SOCK_DGRAM, 0);
  83     if (Sock < 0) {
  84         l2tp_set_errmsg("network_init: socket: %s", strerror(errno));
  85         return -1;
  86     }
  87
  88     me.sin_family = AF_INET;
  89     me.sin_addr = Settings.listen_addr;
  90     me.sin_port = htons((uint16_t) Settings.listen_port);
  91     if (bind(Sock, (struct sockaddr *) &me, sizeof(me)) < 0) {
  92         l2tp_set_errmsg("network_init: bind: %s", strerror(errno));
  93         close(Sock);
  94         Sock = -1;
  95         return -1;
  96     }
  97
  98     /* Set socket non-blocking */
  99     flags = fcntl(Sock, F_GETFL);
 100     flags |= O_NONBLOCK;
 101     fcntl(Sock, F_SETFL, flags);
 102
 103     /* Set up the network read handler */
 104     Event_AddHandler(es, Sock, EVENT_FLAG_READABLE,
 105                      network_readable, NULL);
 106     return Sock;
 107 }
 108
 109 /**********************************************************************
 110 * %FUNCTION: network_readable
 111 * %ARGUMENTS:
 112 *  es -- event selector
 113 *  fd -- socket
 114 *  flags -- event-handling flags telling what happened
 115 *  data -- not used
 116 * %RETURNS:
 117 *  Nothing
 118 * %DESCRIPTION:
 119 *  Called when a packet arrives on the UDP socket.
 120 ***********************************************************************/
 121 static void
 122 network_readable(EventSelector *es,
 123                  int fd,
 124                  unsigned int flags,
 125                  void *data)
 126 {
 127     l2tp_dgram *dgram;
 128
 129     struct sockaddr_in from;
 130     dgram = l2tp_dgram_take_from_wire(&from);
 131     if (!dgram) return;
 132
 133     /* It's a control packet if we get here */
 134     l2tp_tunnel_handle_received_control_datagram(dgram, es, &from);
 135     l2tp_dgram_free(dgram);
 136 }