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         struct ifreq ifr;
  55
  56         cp();
  57
  58         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  59                 device = xstrdup(DEFAULT_DEVICE);
  60
  61         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  62 #ifdef HAVE_LINUX_IF_TUN_H
  63                 if (netname != NULL)
  64                         iface = xstrdup(netname);
  65 #else
  66                 iface = xstrdup(rindex(device, '/') ? rindex(device, '/') + 1 : device);
  67 #endif
  68         device_fd = open(device, O_RDWR | O_NONBLOCK);
  69
  70         if(device_fd < 0) {
  71                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  72                 return false;
  73         }
  74
  75 #ifdef HAVE_LINUX_IF_TUN_H
  76         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  77
  78         memset(&ifr, 0, sizeof(ifr));
  79         if(routing_mode == RMODE_ROUTER) {
  80                 ifr.ifr_flags = IFF_TUN;
  81                 device_type = DEVICE_TYPE_TUN;
  82                 device_info = _("Linux tun/tap device (tun mode)");
  83         } else {
  84                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  85                 device_type = DEVICE_TYPE_TAP;
  86                 device_info = _("Linux tun/tap device (tap mode)");
  87         }
  88
  89         if(iface)
  90                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  91
  92         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
  93                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  94                 if(iface) free(iface);
  95                 iface = xstrdup(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                 if(iface) free(iface);
 100                 iface = xstrdup(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                 if(iface)
 109                         free(iface);
 110                 iface = xstrdup(rindex(device, '/') ? rindex(device, '/') + 1 : device);
 111         }
 112
 113         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 114
 115         return true;
 116 }
 117
 118 void close_device(void) {
 119         cp();
 120
 121         close(device_fd);
 122
 123         free(device);
 124         free(iface);
 125 }
 126
 127 bool read_packet(vpn_packet_t *packet) {
 128         int lenin;
 129
 130         cp();
 131
 132         switch(device_type) {
 133                 case DEVICE_TYPE_TUN:
 134                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 135
 136                         if(lenin <= 0) {
 137                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 138                                            device_info, device, strerror(errno));
 139                                 return false;
 140                         }
 141
 142                         packet->len = lenin + 10;
 143                         break;
 144                 case DEVICE_TYPE_TAP:
 145                         lenin = read(device_fd, packet->data, MTU);
 146
 147                         if(lenin <= 0) {
 148                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 149                                            device_info, device, strerror(errno));
 150                                 return false;
 151                         }
 152
 153                         packet->len = lenin;
 154                         break;
 155                 case DEVICE_TYPE_ETHERTAP:
 156                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 157
 158                         if(lenin <= 0) {
 159                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 160                                            device_info, device, strerror(errno));
 161                                 return false;
 162                         }
 163
 164                         packet->len = lenin - 2;
 165                         break;
 166         }
 167
 168         device_total_in += packet->len;
 169
 170         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 171                            device_info);
 172
 173         return true;
 174 }
 175
 176 bool write_packet(vpn_packet_t *packet) {
 177         cp();
 178
 179         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 180                            packet->len, device_info);
 181
 182         switch(device_type) {
 183                 case DEVICE_TYPE_TUN:
 184                         packet->data[10] = packet->data[11] = 0;
 185                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 186                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 187                                            strerror(errno));
 188                                 return false;
 189                         }
 190                         break;
 191                 case DEVICE_TYPE_TAP:
 192                         if(write(device_fd, packet->data, packet->len) < 0) {
 193                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 194                                            strerror(errno));
 195                                 return false;
 196                         }
 197                         break;
 198                 case DEVICE_TYPE_ETHERTAP:
 199                         *(short int *)(packet->data - 2) = packet->len;
 200
 201                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 202                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 203                                            strerror(errno));
 204                                 return false;
 205                         }
 206                         break;
 207         }
 208
 209         device_total_out += packet->len;
 210
 211         return true;
 212 }
 213
 214 void dump_device_stats(void) {
 215         cp();
 216
 217         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 218         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 219         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 220 }