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) 2001-2005 Ivo Timmermans,
   4                   2001-2006 Guus Sliepen <guus@tinc-vpn.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     $Id$
  21 */
  22
  23 #include "system.h"
  24
  25 #ifdef HAVE_LINUX_IF_TUN_H
  26 #include <linux/if_tun.h>
  27 #define DEFAULT_DEVICE "/dev/net/tun"
  28 #else
  29 #define DEFAULT_DEVICE "/dev/tap0"
  30 #endif
  31
  32 #include "conf.h"
  33 #include "logger.h"
  34 #include "net.h"
  35 #include "route.h"
  36 #include "utils.h"
  37
  38 typedef enum device_type_t {
  39         DEVICE_TYPE_ETHERTAP,
  40         DEVICE_TYPE_TUN,
  41         DEVICE_TYPE_TAP,
  42 } device_type_t;
  43
  44 int device_fd = -1;
  45 static device_type_t device_type;
  46 char *device;
  47 char *iface;
  48 char ifrname[IFNAMSIZ];
  49 char *device_info;
  50
  51 static int device_total_in = 0;
  52 static int device_total_out = 0;
  53
  54 bool setup_device(void) {
  55         struct ifreq ifr;
  56
  57         cp();
  58
  59         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  60                 device = DEFAULT_DEVICE;
  61
  62         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  63 #ifdef HAVE_LINUX_IF_TUN_H
  64                 iface = netname;
  65 #else
  66                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
  67 #endif
  68         device_fd = open(device, O_RDWR | O_NONBLOCK);
  69
  70         if(device_fd < 0) {
  71                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  72                 return false;
  73         }
  74
  75 #ifdef HAVE_LINUX_IF_TUN_H
  76         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  77
  78         memset(&ifr, 0, sizeof(ifr));
  79         if(routing_mode == RMODE_ROUTER) {
  80                 ifr.ifr_flags = IFF_TUN;
  81                 device_type = DEVICE_TYPE_TUN;
  82                 device_info = _("Linux tun/tap device (tun mode)");
  83         } else {
  84                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  85                 device_type = DEVICE_TYPE_TAP;
  86                 device_info = _("Linux tun/tap device (tap mode)");
  87         }
  88
  89         if(iface)
  90                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  91
  92         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
  93                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  94                 iface = ifrname;
  95         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
  96                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
  97                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  98                 iface = ifrname;
  99         } else
 100 #endif
 101         {
 102                 if(routing_mode == RMODE_ROUTER)
 103                         overwrite_mac = true;
 104                 device_info = _("Linux ethertap device");
 105                 device_type = DEVICE_TYPE_ETHERTAP;
 106                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
 107         }
 108
 109         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 110
 111         return true;
 112 }
 113
 114 void close_device(void) {
 115         cp();
 116
 117         close(device_fd);
 118 }
 119
 120 bool read_packet(vpn_packet_t *packet) {
 121         int lenin;
 122
 123         cp();
 124
 125         switch(device_type) {
 126                 case DEVICE_TYPE_TUN:
 127                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 128
 129                         if(lenin <= 0) {
 130                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 131                                            device_info, device, strerror(errno));
 132                                 return false;
 133                         }
 134
 135                         packet->len = lenin + 10;
 136                         break;
 137                 case DEVICE_TYPE_TAP:
 138                         lenin = read(device_fd, packet->data, MTU);
 139
 140                         if(lenin <= 0) {
 141                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 142                                            device_info, device, strerror(errno));
 143                                 return false;
 144                         }
 145
 146                         packet->len = lenin;
 147                         break;
 148                 case DEVICE_TYPE_ETHERTAP:
 149                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 150
 151                         if(lenin <= 0) {
 152                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 153                                            device_info, device, strerror(errno));
 154                                 return false;
 155                         }
 156
 157                         packet->len = lenin - 2;
 158                         break;
 159         }
 160
 161         device_total_in += packet->len;
 162
 163         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 164                            device_info);
 165
 166         return true;
 167 }
 168
 169 bool write_packet(vpn_packet_t *packet) {
 170         cp();
 171
 172         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 173                            packet->len, device_info);
 174
 175         switch(device_type) {
 176                 case DEVICE_TYPE_TUN:
 177                         packet->data[10] = packet->data[11] = 0;
 178                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 179                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 180                                            strerror(errno));
 181                                 return false;
 182                         }
 183                         break;
 184                 case DEVICE_TYPE_TAP:
 185                         if(write(device_fd, packet->data, packet->len) < 0) {
 186                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 187                                            strerror(errno));
 188                                 return false;
 189                         }
 190                         break;
 191                 case DEVICE_TYPE_ETHERTAP:
 192                         *(short int *)(packet->data - 2) = packet->len;
 193
 194                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 195                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 196                                            strerror(errno));
 197                                 return false;
 198                         }
 199                         break;
 200         }
 201
 202         device_total_out += packet->len;
 203
 204         return true;
 205 }
 206
 207 void dump_device_stats(void) {
 208         cp();
 209
 210         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 211         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 212         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 213 }