client/src/tun/linux.c

   1 /*
   2  *  tunnel6
   3  *  Copyright (C) 2010  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *
   5  *  This program is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 #ifdef __linux__
  21 #include <net/if.h>
  22 #include <linux/if_tun.h>
  23 #include <sys/types.h>
  24 #include <sys/socket.h>
  25 #include <sys/ioctl.h>
  26 #include <sys/stat.h>
  27 #include <fcntl.h>
  28 #include <arpa/inet.h>
  29 #include <fcntl.h>
  30 #include <string.h>
  31 #include <stdlib.h>
  32 #include <unistd.h>
  33 #include <stdio.h>
  34 #include "ipv6.h"
  35 #include "tunnel.h"
  36 #include "packet.h"
  37 #include "defaults.h"
  38
  39 static int fd;                                  /* FD of the TUN/TAP device */
  40 static char data[DEFAULT_MTU+1];
  41 static char dev[IFNAMSIZ+1];
  42
  43 extern int fd_tun;                              /* polling FD of the TUN/TAP device */
  44
  45 extern ipv6_addr_t tunip;                       /* IPv6 address obtained from tunnel server */
  46 extern ipv6_addr_t tungw;                       /* IPv6 gateway obtained from tunnel server */
  47 extern ipv6_prefix_t tunpr;                     /* IPv6 prefix obtained from tunnel server */
  48
  49 static int tundev_arch_alloc (int flags)
  50 {
  51         /* try to load tun module / we dont know when its module or built-in */
  52         int r = system ("modprobe -q tun 2>/dev/null >/dev/null");
  53
  54         r = 0;
  55
  56         struct ifreq ifr;
  57         int err;
  58         char *clonedev = DEFAULT_TUNTAP_DEV;
  59
  60         if( (fd = open (clonedev, O_RDWR)) < 0 ) {
  61                 perror ("Opening " DEFAULT_TUNTAP_DEV);
  62                 return fd;
  63         }
  64
  65         memset (&ifr, 0x0, sizeof (ifr));
  66
  67         ifr.ifr_flags = flags;
  68
  69         if (*dev)
  70                 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
  71
  72         if ((err = ioctl (fd, TUNSETIFF, (void *) &ifr)) < 0) {
  73                 perror ("ioctl (TUNSETIFF)");
  74                 close (fd);
  75                 return err;
  76         }
  77
  78         strcpy (dev, ifr.ifr_name);
  79
  80         return fd;
  81 }
  82
  83 int tundev_arch_recv ()
  84 {
  85         int ret = read (fd, data, DEFAULT_MTU);
  86
  87         if (ret < 1) {
  88                 return 0;
  89         }
  90
  91         data[ret] = '\0';
  92
  93         return ret;
  94 }
  95
  96 int tundev_arch_poll ()
  97 {
  98         int ret = tundev_arch_recv ();
  99
 100         if (!ret)
 101                 return 0;
 102
 103         struct proto_ipv6_t *ip = (struct proto_ipv6_t *) &data;
 104
 105         if (!ipv6_cmp (ip->src, tunip) && !ipv6_cmp_prefix (tunpr, (unsigned char *) ip->src)) {
 106                 printf ("WARNING -> This is not our packet\n");
 107                 return 0;
 108         }
 109
 110         return tunnel_send (data, ret);
 111 }
 112
 113 int tundev_arch_send (char *packet, unsigned len)
 114 {
 115         if (write (fd, packet, len) == -1) {
 116                 printf ("ERROR -> tap_send ()\n");
 117                 return -1;
 118         }
 119
 120         return 0;
 121 }
 122
 123 int tundev_arch_setup ()
 124 {
 125         sprintf (data, "ip link set %s up", dev);
 126         int r = system (data);
 127
 128         sprintf (data, "ip link set mtu %u dev %s", DEFAULT_MTU - 40, dev);
 129         r = system (data);
 130
 131         char ipv6[64];
 132         inet_ntop (AF_INET6, &tunip, ipv6, 64);
 133
 134         sprintf (data, "ip -6 addr add %s/%u dev %s", ipv6, 64, dev);
 135         r = system (data);
 136
 137         inet_ntop (AF_INET6, &tungw, ipv6, 64);
 138
 139         sprintf (data, "ip -6 ro add default via %s dev %s", ipv6, dev);
 140         r = system (data);
 141
 142         return 0;
 143 }
 144
 145 int tundev_arch_init ()
 146 {
 147         strncpy (dev, DEFAULT_TUNNEL6_DEV, IFNAMSIZ);
 148
 149         /* initialize TUN interface, which operates on 3rd network layer (IP) */
 150         fd_tun = tundev_arch_alloc (IFF_TUN | IFF_NO_PI | IFF_POINTOPOINT);
 151
 152         if (fd_tun < 0) {
 153                 printf ("ERROR -> TUN/TAP interface '%s' failed\n", DEFAULT_TUNNEL6_DEV);
 154                 return -1;
 155         }
 156
 157         printf ("> Tunnel device '%s' was created\n", dev);
 158
 159         return 0;
 160 }
 161 #endif