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 {
  56         struct ifreq ifr;
  57
  58         cp();
  59
  60         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  61                 device = DEFAULT_DEVICE;
  62
  63         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  64 #ifdef HAVE_LINUX_IF_TUN_H
  65                 iface = netname;
  66 #else
  67                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
  68 #endif
  69         device_fd = open(device, O_RDWR | O_NONBLOCK);
  70
  71         if(device_fd < 0) {
  72                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  73                 return false;
  74         }
  75
  76 #ifdef HAVE_LINUX_IF_TUN_H
  77         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  78
  79         memset(&ifr, 0, sizeof(ifr));
  80         if(routing_mode == RMODE_ROUTER) {
  81                 ifr.ifr_flags = IFF_TUN;
  82                 device_type = DEVICE_TYPE_TUN;
  83                 device_info = _("Linux tun/tap device (tun mode)");
  84         } else {
  85                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  86                 device_type = DEVICE_TYPE_TAP;
  87                 device_info = _("Linux tun/tap device (tap mode)");
  88         }
  89
  90         if(iface)
  91                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  92
  93         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
  94                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  95                 iface = ifrname;
  96         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
  97                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
  98                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  99                 iface = ifrname;
 100         } else
 101 #endif
 102         {
 103                 if(routing_mode == RMODE_ROUTER)
 104                         overwrite_mac = true;
 105                 device_info = _("Linux ethertap device");
 106                 device_type = DEVICE_TYPE_ETHERTAP;
 107                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
 108         }
 109
 110         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 111
 112         return true;
 113 }
 114
 115 void close_device(void)
 116 {
 117         cp();
 118
 119         close(device_fd);
 120 }
 121
 122 bool read_packet(vpn_packet_t *packet)
 123 {
 124         int lenin;
 125
 126         cp();
 127
 128         switch(device_type) {
 129                 case DEVICE_TYPE_TUN:
 130                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 131
 132                         if(lenin <= 0) {
 133                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 134                                            device_info, device, strerror(errno));
 135                                 return false;
 136                         }
 137
 138                         packet->len = lenin + 10;
 139                         break;
 140                 case DEVICE_TYPE_TAP:
 141                         lenin = read(device_fd, packet->data, MTU);
 142
 143                         if(lenin <= 0) {
 144                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 145                                            device_info, device, strerror(errno));
 146                                 return false;
 147                         }
 148
 149                         packet->len = lenin;
 150                         break;
 151                 case DEVICE_TYPE_ETHERTAP:
 152                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 153
 154                         if(lenin <= 0) {
 155                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 156                                            device_info, device, strerror(errno));
 157                                 return false;
 158                         }
 159
 160                         packet->len = lenin - 2;
 161                         break;
 162         }
 163
 164         device_total_in += packet->len;
 165
 166         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 167                            device_info);
 168
 169         return true;
 170 }
 171
 172 bool write_packet(vpn_packet_t *packet)
 173 {
 174         cp();
 175
 176         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 177                            packet->len, device_info);
 178
 179         switch(device_type) {
 180                 case DEVICE_TYPE_TUN:
 181                         packet->data[10] = packet->data[11] = 0;
 182                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 183                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 184                                            strerror(errno));
 185                                 return false;
 186                         }
 187                         break;
 188                 case DEVICE_TYPE_TAP:
 189                         if(write(device_fd, packet->data, packet->len) < 0) {
 190                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 191                                            strerror(errno));
 192                                 return false;
 193                         }
 194                         break;
 195                 case DEVICE_TYPE_ETHERTAP:
 196                         *(short int *)(packet->data - 2) = packet->len;
 197
 198                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 199                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 200                                            strerror(errno));
 201                                 return false;
 202                         }
 203                         break;
 204         }
 205
 206         device_total_out += packet->len;
 207
 208         return true;
 209 }
 210
 211 void dump_device_stats(void)
 212 {
 213         cp();
 214
 215         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 216         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 217         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 218 }