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 {
  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                 if (netname != NULL)
  67                         iface = xstrdup(netname);
  68 #else
  69                 iface = xstrdup(rindex(device, '/') ? rindex(device, '/') + 1 : device);
  70 #endif
  71         device_fd = open(device, O_RDWR | O_NONBLOCK);
  72
  73         if(device_fd < 0) {
  74                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  75                 return false;
  76         }
  77
  78 #ifdef HAVE_LINUX_IF_TUN_H
  79         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  80
  81         memset(&ifr, 0, sizeof(ifr));
  82         if(routing_mode == RMODE_ROUTER) {
  83                 ifr.ifr_flags = IFF_TUN;
  84                 device_type = DEVICE_TYPE_TUN;
  85                 device_info = _("Linux tun/tap device (tun mode)");
  86         } else {
  87                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  88                 device_type = DEVICE_TYPE_TAP;
  89                 device_info = _("Linux tun/tap device (tap mode)");
  90         }
  91
  92         if(iface)
  93                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  94
  95         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
  96                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  97                 if(iface) free(iface);
  98                 iface = xstrdup(ifrname);
  99         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
 100                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
 101                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 102                 if(iface) free(iface);
 103                 iface = xstrdup(ifrname);
 104         } else
 105 #endif
 106         {
 107                 if(routing_mode == RMODE_ROUTER)
 108                         overwrite_mac = true;
 109                 device_info = _("Linux ethertap device");
 110                 device_type = DEVICE_TYPE_ETHERTAP;
 111                 if(iface)
 112                         free(iface);
 113                 iface = xstrdup(rindex(device, '/') ? rindex(device, '/') + 1 : device);
 114         }
 115
 116         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 117
 118         return true;
 119 }
 120
 121 void close_device(void)
 122 {
 123         cp();
 124
 125         close(device_fd);
 126
 127         free(device);
 128         free(iface);
 129 }
 130
 131 bool read_packet(vpn_packet_t *packet)
 132 {
 133         int lenin;
 134
 135         cp();
 136
 137         switch(device_type) {
 138                 case DEVICE_TYPE_TUN:
 139                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 140
 141                         if(lenin <= 0) {
 142                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 143                                            device_info, device, strerror(errno));
 144                                 return false;
 145                         }
 146
 147                         packet->len = lenin + 10;
 148                         break;
 149                 case DEVICE_TYPE_TAP:
 150                         lenin = read(device_fd, packet->data, MTU);
 151
 152                         if(lenin <= 0) {
 153                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 154                                            device_info, device, strerror(errno));
 155                                 return false;
 156                         }
 157
 158                         packet->len = lenin;
 159                         break;
 160                 case DEVICE_TYPE_ETHERTAP:
 161                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 162
 163                         if(lenin <= 0) {
 164                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 165                                            device_info, device, strerror(errno));
 166                                 return false;
 167                         }
 168
 169                         packet->len = lenin - 2;
 170                         break;
 171         }
 172
 173         device_total_in += packet->len;
 174
 175         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 176                            device_info);
 177
 178         return true;
 179 }
 180
 181 bool write_packet(vpn_packet_t *packet)
 182 {
 183         cp();
 184
 185         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 186                            packet->len, device_info);
 187
 188         switch(device_type) {
 189                 case DEVICE_TYPE_TUN:
 190                         packet->data[10] = packet->data[11] = 0;
 191                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 192                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 193                                            strerror(errno));
 194                                 return false;
 195                         }
 196                         break;
 197                 case DEVICE_TYPE_TAP:
 198                         if(write(device_fd, packet->data, packet->len) < 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                 case DEVICE_TYPE_ETHERTAP:
 205                         *(short int *)(packet->data - 2) = packet->len;
 206
 207                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 208                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 209                                            strerror(errno));
 210                                 return false;
 211                         }
 212                         break;
 213         }
 214
 215         device_total_out += packet->len;
 216
 217         return true;
 218 }
 219
 220 void dump_device_stats(void)
 221 {
 222         cp();
 223
 224         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 225         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 226         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 227 }