tinc-vpn.org Git - tinc/blob - src/linux/device.c

   1 /*
   2     device.c -- Interaction with Linux ethertap and tun/tap device
   3     Copyright (C) 2001-2002 Ivo Timmermans <ivo@o2w.nl>,
   4                   2001-2002 Guus Sliepen <guus@sliepen.eu.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id: device.c,v 1.1.2.14 2003/06/11 19:09:52 guus Exp $
  21 */
  22
  23 #include "config.h"
  24
  25 #include <stdio.h>
  26 #include <errno.h>
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <fcntl.h>
  30 #include <net/if.h>
  31 #include <unistd.h>
  32 #include <syslog.h>
  33 #include <string.h>
  34 #include <sys/ioctl.h>
  35
  36 #ifdef HAVE_TUNTAP
  37 #ifdef LINUX_IF_TUN_H
  38 #include LINUX_IF_TUN_H
  39 #else
  40 #include <linux/if_tun.h>
  41 #endif
  42 #define DEFAULT_DEVICE "/dev/net/tun"
  43 #else
  44 #define DEFAULT_DEVICE "/dev/tap0"
  45 #endif
  46
  47 #include <utils.h>
  48 #include "conf.h"
  49 #include "net.h"
  50 #include "subnet.h"
  51 #include "route.h"
  52
  53 #include "system.h"
  54
  55 enum {
  56         DEVICE_TYPE_ETHERTAP,
  57         DEVICE_TYPE_TUN,
  58         DEVICE_TYPE_TAP,
  59 };
  60
  61 int device_fd = -1;
  62 int device_type;
  63 char *device;
  64 char *interface;
  65 char ifrname[IFNAMSIZ];
  66 char *device_info;
  67
  68 int device_total_in = 0;
  69 int device_total_out = 0;
  70
  71 extern subnet_t mymac;
  72
  73 /*
  74   open the local ethertap device
  75 */
  76 int setup_device(void)
  77 {
  78         struct ifreq ifr;
  79
  80         cp();
  81
  82         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  83                 device = DEFAULT_DEVICE;
  84
  85         if(!get_config_string(lookup_config(config_tree, "Interface"), &interface))
  86 #ifdef HAVE_TUNTAP
  87                 interface = netname;
  88 #else
  89                 interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
  90 #endif
  91         device_fd = open(device, O_RDWR | O_NONBLOCK);
  92
  93         if(device_fd < 0) {
  94                 syslog(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  95                 return -1;
  96         }
  97
  98         /* Set default MAC address for ethertap devices */
  99         mymac.type = SUBNET_MAC;
 100         mymac.net.mac.address.x[0] = 0xfe;
 101         mymac.net.mac.address.x[1] = 0xfd;
 102         mymac.net.mac.address.x[2] = 0x00;
 103         mymac.net.mac.address.x[3] = 0x00;
 104         mymac.net.mac.address.x[4] = 0x00;
 105         mymac.net.mac.address.x[5] = 0x00;
 106
 107 #ifdef HAVE_TUNTAP
 108         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
 109
 110         memset(&ifr, 0, sizeof(ifr));
 111         if(routing_mode == RMODE_ROUTER) {
 112                 ifr.ifr_flags = IFF_TUN;
 113                 device_type = DEVICE_TYPE_TUN;
 114                 device_info = _("Linux tun/tap device (tun mode)");
 115         } else {
 116                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 117                 device_type = DEVICE_TYPE_TAP;
 118                 device_info = _("Linux tun/tap device (tap mode)");
 119         }
 120
 121         if(interface)
 122                 strncpy(ifr.ifr_name, interface, IFNAMSIZ);
 123
 124         if(!ioctl(device_fd, TUNSETIFF, (void *) &ifr)) {
 125                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 126                 interface = ifrname;
 127         } else if(!ioctl(device_fd, (('T' << 8) | 202), (void *) &ifr)) {
 128                 syslog(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
 129                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 130                 interface = ifrname;
 131         } else
 132 #endif
 133         {
 134                 device_info = _("Linux ethertap device");
 135                 device_type = DEVICE_TYPE_ETHERTAP;
 136                 interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
 137         }
 138
 139         syslog(LOG_INFO, _("%s is a %s"), device, device_info);
 140
 141         return 0;
 142 }
 143
 144 void close_device(void)
 145 {
 146         cp();
 147
 148         close(device_fd);
 149 }
 150
 151 /*
 152   read, encrypt and send data that is
 153   available through the ethertap device
 154 */
 155 int read_packet(vpn_packet_t *packet)
 156 {
 157         int lenin;
 158
 159         cp();
 160
 161         switch(device_type) {
 162                 case DEVICE_TYPE_TUN:
 163                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 164
 165                         if(lenin <= 0) {
 166                                 syslog(LOG_ERR, _("Error while reading from %s %s: %s"),
 167                                            device_info, device, strerror(errno));
 168                                 return -1;
 169                         }
 170
 171                         packet->len = lenin + 10;
 172                         break;
 173                 case DEVICE_TYPE_TAP:
 174                         lenin = read(device_fd, packet->data, MTU);
 175
 176                         if(lenin <= 0) {
 177                                 syslog(LOG_ERR, _("Error while reading from %s %s: %s"),
 178                                            device_info, device, strerror(errno));
 179                                 return -1;
 180                         }
 181
 182                         packet->len = lenin;
 183                         break;
 184                 case DEVICE_TYPE_ETHERTAP:
 185                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 186
 187                         if(lenin <= 0) {
 188                                 syslog(LOG_ERR, _("Error while reading from %s %s: %s"),
 189                                            device_info, device, strerror(errno));
 190                                 return -1;
 191                         }
 192
 193                         packet->len = lenin - 2;
 194                         break;
 195         }
 196
 197         device_total_in += packet->len;
 198
 199         if(debug_lvl >= DEBUG_TRAFFIC) {
 200                 syslog(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 201                            device_info);
 202         }
 203
 204         return 0;
 205 }
 206
 207 int write_packet(vpn_packet_t *packet)
 208 {
 209         cp();
 210
 211         if(debug_lvl >= DEBUG_TRAFFIC)
 212                 syslog(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 213                            packet->len, device_info);
 214
 215         switch(device_type) {
 216                 case DEVICE_TYPE_TUN:
 217                         packet->data[10] = packet->data[11] = 0;
 218                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 219                                 syslog(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 220                                            strerror(errno));
 221                                 return -1;
 222                         }
 223                         break;
 224                 case DEVICE_TYPE_TAP:
 225                         if(write(device_fd, packet->data, packet->len) < 0) {
 226                                 syslog(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 227                                            strerror(errno));
 228                                 return -1;
 229                         }
 230                         break;
 231                 case DEVICE_TYPE_ETHERTAP:
 232                         *(short int *)(packet->data - 2) = packet->len;
 233
 234                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 235                                 syslog(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 236                                            strerror(errno));
 237                                 return -1;
 238                         }
 239                         break;
 240         }
 241
 242         device_total_out += packet->len;
 243
 244         return 0;
 245 }
 246
 247 void dump_device_stats(void)
 248 {
 249         cp();
 250
 251         syslog(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 252         syslog(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 253         syslog(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 254 }