www.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 along
  17     with this program; if not, write to the Free Software Foundation, Inc.,
  18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21 #include "system.h"
  22
  23 #ifdef HAVE_LINUX_IF_TUN_H
  24 #include <linux/if_tun.h>
  25 #define DEFAULT_DEVICE "/dev/net/tun"
  26 #else
  27 #define DEFAULT_DEVICE "/dev/tap0"
  28 #endif
  29
  30 #include "conf.h"
  31 #include "logger.h"
  32 #include "net.h"
  33 #include "route.h"
  34 #include "utils.h"
  35 #include "xalloc.h"
  36
  37 typedef enum device_type_t {
  38         DEVICE_TYPE_ETHERTAP,
  39         DEVICE_TYPE_TUN,
  40         DEVICE_TYPE_TAP,
  41 } device_type_t;
  42
  43 int device_fd = -1;
  44 static device_type_t device_type;
  45 char *device = NULL;
  46 char *iface = NULL;
  47 static char ifrname[IFNAMSIZ];
  48 static char *device_info;
  49
  50 static int device_total_in = 0;
  51 static int device_total_out = 0;
  52
  53 bool setup_device(void)
  54 {
  55         struct ifreq ifr;
  56
  57         cp();
  58
  59         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  60                 device = xstrdup(DEFAULT_DEVICE);
  61
  62         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  63 #ifdef HAVE_LINUX_IF_TUN_H
  64                 if (netname != NULL)
  65                         iface = xstrdup(netname);
  66 #else
  67                 iface = xstrdup(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                 if(iface) free(iface);
  96                 iface = xstrdup(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                 if(iface) free(iface);
 101                 iface = xstrdup(ifrname);
 102         } else
 103 #endif
 104         {
 105                 if(routing_mode == RMODE_ROUTER)
 106                         overwrite_mac = true;
 107                 device_info = _("Linux ethertap device");
 108                 device_type = DEVICE_TYPE_ETHERTAP;
 109                 if(iface)
 110                         free(iface);
 111                 iface = xstrdup(rindex(device, '/') ? rindex(device, '/') + 1 : device);
 112         }
 113
 114         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 115
 116         return true;
 117 }
 118
 119 void close_device(void)
 120 {
 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 {
 131         int lenin;
 132
 133         cp();
 134
 135         switch(device_type) {
 136                 case DEVICE_TYPE_TUN:
 137                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 138
 139                         if(lenin <= 0) {
 140                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 141                                            device_info, device, strerror(errno));
 142                                 return false;
 143                         }
 144
 145                         packet->len = lenin + 10;
 146                         break;
 147                 case DEVICE_TYPE_TAP:
 148                         lenin = read(device_fd, packet->data, MTU);
 149
 150                         if(lenin <= 0) {
 151                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 152                                            device_info, device, strerror(errno));
 153                                 return false;
 154                         }
 155
 156                         packet->len = lenin;
 157                         break;
 158                 case DEVICE_TYPE_ETHERTAP:
 159                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 160
 161                         if(lenin <= 0) {
 162                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 163                                            device_info, device, strerror(errno));
 164                                 return false;
 165                         }
 166
 167                         packet->len = lenin - 2;
 168                         break;
 169         }
 170
 171         device_total_in += packet->len;
 172
 173         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 174                            device_info);
 175
 176         return true;
 177 }
 178
 179 bool write_packet(vpn_packet_t *packet)
 180 {
 181         cp();
 182
 183         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 184                            packet->len, device_info);
 185
 186         switch(device_type) {
 187                 case DEVICE_TYPE_TUN:
 188                         packet->data[10] = packet->data[11] = 0;
 189                         if(write(device_fd, packet->data + 10, packet->len - 10) < 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_TAP:
 196                         if(write(device_fd, packet->data, packet->len) < 0) {
 197                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 198                                            strerror(errno));
 199                                 return false;
 200                         }
 201                         break;
 202                 case DEVICE_TYPE_ETHERTAP:
 203                         *(short int *)(packet->data - 2) = packet->len;
 204
 205                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 206                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 207                                            strerror(errno));
 208                                 return false;
 209                         }
 210                         break;
 211         }
 212
 213         device_total_out += packet->len;
 214
 215         return true;
 216 }
 217
 218 void dump_device_stats(void)
 219 {
 220         cp();
 221
 222         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 223         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 224         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 225 }