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                   2001-2009 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 = NULL;
  48 char *iface = NULL;
  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         struct ifreq ifr;
  57
  58         cp();
  59
  60         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  61                 device = xstrdup(DEFAULT_DEVICE);
  62
  63         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  64 #ifdef HAVE_LINUX_IF_TUN_H
  65                 if (netname != NULL)
  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                 if(iface) free(iface);
  97                 iface = xstrdup(ifrname);
  98         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
  99                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
 100                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 101                 if(iface) free(iface);
 102                 iface = xstrdup(ifrname);
 103         } else
 104 #endif
 105         {
 106                 if(routing_mode == RMODE_ROUTER)
 107                         overwrite_mac = true;
 108                 device_info = _("Linux ethertap device");
 109                 device_type = DEVICE_TYPE_ETHERTAP;
 110                 if(iface)
 111                         free(iface);
 112                 iface = xstrdup(rindex(device, '/') ? rindex(device, '/') + 1 : device);
 113         }
 114
 115         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 116
 117         return true;
 118 }
 119
 120 void close_device(void) {
 121         cp();
 122
 123         close(device_fd);
 124
 125         free(device);
 126         free(iface);
 127 }
 128
 129 bool read_packet(vpn_packet_t *packet) {
 130         int inlen;
 131
 132         cp();
 133
 134         switch(device_type) {
 135                 case DEVICE_TYPE_TUN:
 136                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 137
 138                         if(inlen <= 0) {
 139                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 140                                            device_info, device, strerror(errno));
 141                                 return false;
 142                         }
 143
 144                         packet->len = inlen + 10;
 145                         break;
 146                 case DEVICE_TYPE_TAP:
 147                         inlen = read(device_fd, packet->data, MTU);
 148
 149                         if(inlen <= 0) {
 150                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 151                                            device_info, device, strerror(errno));
 152                                 return false;
 153                         }
 154
 155                         packet->len = inlen;
 156                         break;
 157                 case DEVICE_TYPE_ETHERTAP:
 158                         inlen = read(device_fd, packet->data - 2, MTU + 2);
 159
 160                         if(inlen <= 0) {
 161                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 162                                            device_info, device, strerror(errno));
 163                                 return false;
 164                         }
 165
 166                         packet->len = inlen - 2;
 167                         break;
 168         }
 169
 170         device_total_in += packet->len;
 171
 172         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 173                            device_info);
 174
 175         return true;
 176 }
 177
 178 bool write_packet(vpn_packet_t *packet) {
 179         cp();
 180
 181         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 182                            packet->len, device_info);
 183
 184         switch(device_type) {
 185                 case DEVICE_TYPE_TUN:
 186                         packet->data[10] = packet->data[11] = 0;
 187                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 188                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 189                                            strerror(errno));
 190                                 return false;
 191                         }
 192                         break;
 193                 case DEVICE_TYPE_TAP:
 194                         if(write(device_fd, packet->data, packet->len) < 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                 case DEVICE_TYPE_ETHERTAP:
 201                         *(short int *)(packet->data - 2) = packet->len;
 202
 203                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 204                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 205                                            strerror(errno));
 206                                 return false;
 207                         }
 208                         break;
 209         }
 210
 211         device_total_out += packet->len;
 212
 213         return true;
 214 }
 215
 216 void dump_device_stats(void) {
 217         cp();
 218
 219         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 220         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 221         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 222 }