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 = 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                 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 {
 122         cp();
 123
 124         close(device_fd);
 125
 126         free(device);
 127         free(iface);
 128 }
 129
 130 bool read_packet(vpn_packet_t *packet)
 131 {
 132         int lenin;
 133
 134         cp();
 135
 136         switch(device_type) {
 137                 case DEVICE_TYPE_TUN:
 138                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 139
 140                         if(lenin <= 0) {
 141                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 142                                            device_info, device, strerror(errno));
 143                                 return false;
 144                         }
 145
 146                         packet->len = lenin + 10;
 147                         break;
 148                 case DEVICE_TYPE_TAP:
 149                         lenin = read(device_fd, packet->data, MTU);
 150
 151                         if(lenin <= 0) {
 152                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 153                                            device_info, device, strerror(errno));
 154                                 return false;
 155                         }
 156
 157                         packet->len = lenin;
 158                         break;
 159                 case DEVICE_TYPE_ETHERTAP:
 160                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 161
 162                         if(lenin <= 0) {
 163                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 164                                            device_info, device, strerror(errno));
 165                                 return false;
 166                         }
 167
 168                         packet->len = lenin - 2;
 169                         break;
 170         }
 171
 172         device_total_in += packet->len;
 173
 174         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 175                            device_info);
 176
 177         return true;
 178 }
 179
 180 bool write_packet(vpn_packet_t *packet)
 181 {
 182         cp();
 183
 184         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 185                            packet->len, device_info);
 186
 187         switch(device_type) {
 188                 case DEVICE_TYPE_TUN:
 189                         packet->data[10] = packet->data[11] = 0;
 190                         if(write(device_fd, packet->data + 10, packet->len - 10) < 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_TAP:
 197                         if(write(device_fd, packet->data, packet->len) < 0) {
 198                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 199                                            strerror(errno));
 200                                 return false;
 201                         }
 202                         break;
 203                 case DEVICE_TYPE_ETHERTAP:
 204                         *(short int *)(packet->data - 2) = packet->len;
 205
 206                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 207                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 208                                            strerror(errno));
 209                                 return false;
 210                         }
 211                         break;
 212         }
 213
 214         device_total_out += packet->len;
 215
 216         return true;
 217 }
 218
 219 void dump_device_stats(void)
 220 {
 221         cp();
 222
 223         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 224         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 225         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 226 }