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 #include "xalloc.h"
  38
  39 typedef enum device_type_t {
  40         DEVICE_TYPE_ETHERTAP,
  41         DEVICE_TYPE_TUN,
  42         DEVICE_TYPE_TAP,
  43 } device_type_t;
  44
  45 int device_fd = -1;
  46 static device_type_t device_type;
  47 char *device;
  48 char *iface;
  49 static char ifrname[IFNAMSIZ];
  50 static char *device_info;
  51
  52 static int device_total_in = 0;
  53 static int device_total_out = 0;
  54
  55 bool setup_device(void)
  56 {
  57         struct ifreq ifr;
  58
  59         cp();
  60
  61         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  62                 device = xstrdup(DEFAULT_DEVICE);
  63
  64         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  65 #ifdef HAVE_LINUX_IF_TUN_H
  66                 iface = xstrdup(netname);
  67 #else
  68                 iface = xstrdup(rindex(device, '/') ? rindex(device, '/') + 1 : device);
  69 #endif
  70         device_fd = open(device, O_RDWR | O_NONBLOCK);
  71
  72         if(device_fd < 0) {
  73                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  74                 return false;
  75         }
  76
  77 #ifdef HAVE_LINUX_IF_TUN_H
  78         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  79
  80         memset(&ifr, 0, sizeof(ifr));
  81         if(routing_mode == RMODE_ROUTER) {
  82                 ifr.ifr_flags = IFF_TUN;
  83                 device_type = DEVICE_TYPE_TUN;
  84                 device_info = _("Linux tun/tap device (tun mode)");
  85         } else {
  86                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  87                 device_type = DEVICE_TYPE_TAP;
  88                 device_info = _("Linux tun/tap device (tap mode)");
  89         }
  90
  91         if(iface)
  92                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  93
  94         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
  95                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  96                 iface = ifrname;
  97         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
  98                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
  99                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 100                 iface = ifrname;
 101         } else
 102 #endif
 103         {
 104                 if(routing_mode == RMODE_ROUTER)
 105                         overwrite_mac = true;
 106                 device_info = _("Linux ethertap device");
 107                 device_type = DEVICE_TYPE_ETHERTAP;
 108                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
 109         }
 110
 111         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 112
 113         return true;
 114 }
 115
 116 void close_device(void)
 117 {
 118         cp();
 119
 120         close(device_fd);
 121 }
 122
 123 bool read_packet(vpn_packet_t *packet)
 124 {
 125         int lenin;
 126
 127         cp();
 128
 129         switch(device_type) {
 130                 case DEVICE_TYPE_TUN:
 131                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 132
 133                         if(lenin <= 0) {
 134                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 135                                            device_info, device, strerror(errno));
 136                                 return false;
 137                         }
 138
 139                         packet->len = lenin + 10;
 140                         break;
 141                 case DEVICE_TYPE_TAP:
 142                         lenin = read(device_fd, packet->data, MTU);
 143
 144                         if(lenin <= 0) {
 145                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 146                                            device_info, device, strerror(errno));
 147                                 return false;
 148                         }
 149
 150                         packet->len = lenin;
 151                         break;
 152                 case DEVICE_TYPE_ETHERTAP:
 153                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 154
 155                         if(lenin <= 0) {
 156                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 157                                            device_info, device, strerror(errno));
 158                                 return false;
 159                         }
 160
 161                         packet->len = lenin - 2;
 162                         break;
 163         }
 164
 165         device_total_in += packet->len;
 166
 167         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 168                            device_info);
 169
 170         return true;
 171 }
 172
 173 bool write_packet(vpn_packet_t *packet)
 174 {
 175         cp();
 176
 177         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 178                            packet->len, device_info);
 179
 180         switch(device_type) {
 181                 case DEVICE_TYPE_TUN:
 182                         packet->data[10] = packet->data[11] = 0;
 183                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 184                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 185                                            strerror(errno));
 186                                 return false;
 187                         }
 188                         break;
 189                 case DEVICE_TYPE_TAP:
 190                         if(write(device_fd, packet->data, packet->len) < 0) {
 191                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 192                                            strerror(errno));
 193                                 return false;
 194                         }
 195                         break;
 196                 case DEVICE_TYPE_ETHERTAP:
 197                         *(short int *)(packet->data - 2) = packet->len;
 198
 199                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 200                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 201                                            strerror(errno));
 202                                 return false;
 203                         }
 204                         break;
 205         }
 206
 207         device_total_out += packet->len;
 208
 209         return true;
 210 }
 211
 212 void dump_device_stats(void)
 213 {
 214         cp();
 215
 216         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 217         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 218         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 219 }