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) 2001-2003 Ivo Timmermans <ivo@o2w.nl>,
   4                   2001-2003 Guus Sliepen <guus@sliepen.eu.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: device.c,v 1.1.2.20 2003/07/22 20:55:21 guus Exp $
  21 */
  22
  23 #include "system.h"
  24
  25 #ifdef HAVE_TUNTAP
  26 #ifdef LINUX_IF_TUN_H
  27 #include LINUX_IF_TUN_H
  28 #else
  29 #include <linux/if_tun.h>
  30 #endif
  31 #define DEFAULT_DEVICE "/dev/net/tun"
  32 #else
  33 #define DEFAULT_DEVICE "/dev/tap0"
  34 #endif
  35
  36 #include "conf.h"
  37 #include "logger.h"
  38 #include "net.h"
  39 #include "route.h"
  40 #include "utils.h"
  41
  42 typedef enum device_type_t {
  43         DEVICE_TYPE_ETHERTAP,
  44         DEVICE_TYPE_TUN,
  45         DEVICE_TYPE_TAP,
  46 } device_type_t;
  47
  48 int device_fd = -1;
  49 device_type_t device_type;
  50 char *device;
  51 char *iface;
  52 char ifrname[IFNAMSIZ];
  53 char *device_info;
  54
  55 int device_total_in = 0;
  56 int device_total_out = 0;
  57
  58 bool setup_device(void)
  59 {
  60         struct ifreq ifr;
  61
  62         cp();
  63
  64         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  65                 device = DEFAULT_DEVICE;
  66
  67         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  68 #ifdef HAVE_TUNTAP
  69                 iface = netname;
  70 #else
  71                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
  72 #endif
  73         device_fd = open(device, O_RDWR | O_NONBLOCK);
  74
  75         if(device_fd < 0) {
  76                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  77                 return false;
  78         }
  79
  80 #ifdef HAVE_TUNTAP
  81         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  82
  83         memset(&ifr, 0, sizeof(ifr));
  84         if(routing_mode == RMODE_ROUTER) {
  85                 ifr.ifr_flags = IFF_TUN;
  86                 device_type = DEVICE_TYPE_TUN;
  87                 device_info = _("Linux tun/tap device (tun mode)");
  88         } else {
  89                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  90                 device_type = DEVICE_TYPE_TAP;
  91                 device_info = _("Linux tun/tap device (tap mode)");
  92         }
  93
  94         if(iface)
  95                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  96
  97         if(!ioctl(device_fd, TUNSETIFF, (void *) &ifr)) {
  98                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  99                 iface = ifrname;
 100         } else if(!ioctl(device_fd, (('T' << 8) | 202), (void *) &ifr)) {
 101                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
 102                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 103                 iface = 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                 iface = 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
 126 bool read_packet(vpn_packet_t *packet)
 127 {
 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 {
 178         cp();
 179
 180         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 181                            packet->len, device_info);
 182
 183         switch(device_type) {
 184                 case DEVICE_TYPE_TUN:
 185                         packet->data[10] = packet->data[11] = 0;
 186                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 187                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 188                                            strerror(errno));
 189                                 return false;
 190                         }
 191                         break;
 192                 case DEVICE_TYPE_TAP:
 193                         if(write(device_fd, packet->data, packet->len) < 0) {
 194                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 195                                            strerror(errno));
 196                                 return false;
 197                         }
 198                         break;
 199                 case DEVICE_TYPE_ETHERTAP:
 200                         *(short int *)(packet->data - 2) = packet->len;
 201
 202                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 203                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 204                                            strerror(errno));
 205                                 return false;
 206                         }
 207                         break;
 208         }
 209
 210         device_total_out += packet->len;
 211
 212         return true;
 213 }
 214
 215 void dump_device_stats(void)
 216 {
 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 }