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                   2001-2006 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 #include <linux/if_tun.h>
  26 #define DEFAULT_DEVICE "/dev/net/tun"
  27
  28 #include "conf.h"
  29 #include "logger.h"
  30 #include "net.h"
  31 #include "route.h"
  32 #include "utils.h"
  33
  34 typedef enum device_type_t {
  35         DEVICE_TYPE_ETHERTAP,
  36         DEVICE_TYPE_TUN,
  37         DEVICE_TYPE_TAP,
  38 } device_type_t;
  39
  40 int device_fd = -1;
  41 static device_type_t device_type;
  42 char *device;
  43 char *iface;
  44 char ifrname[IFNAMSIZ];
  45 char *device_info;
  46
  47 static int device_total_in = 0;
  48 static int device_total_out = 0;
  49
  50 bool setup_device(void)
  51 {
  52         struct ifreq ifr;
  53
  54         cp();
  55
  56         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  57                 device = DEFAULT_DEVICE;
  58
  59         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  60 #ifdef HAVE_TUNTAP
  61                 iface = netname;
  62 #else
  63                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
  64 #endif
  65         device_fd = open(device, O_RDWR | O_NONBLOCK);
  66
  67         if(device_fd < 0) {
  68                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  69                 return false;
  70         }
  71
  72 #ifdef HAVE_TUNTAP
  73         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  74
  75         memset(&ifr, 0, sizeof(ifr));
  76         if(routing_mode == RMODE_ROUTER) {
  77                 ifr.ifr_flags = IFF_TUN;
  78                 device_type = DEVICE_TYPE_TUN;
  79                 device_info = _("Linux tun/tap device (tun mode)");
  80         } else {
  81                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  82                 device_type = DEVICE_TYPE_TAP;
  83                 device_info = _("Linux tun/tap device (tap mode)");
  84         }
  85
  86         if(iface)
  87                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  88
  89         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
  90                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  91                 iface = ifrname;
  92         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
  93                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
  94                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  95                 iface = ifrname;
  96         } else
  97 #endif
  98         {
  99                 if(routing_mode == RMODE_ROUTER)
 100                         overwrite_mac = true;
 101                 device_info = _("Linux ethertap device");
 102                 device_type = DEVICE_TYPE_ETHERTAP;
 103                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
 104         }
 105
 106         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 107
 108         return true;
 109 }
 110
 111 void close_device(void)
 112 {
 113         cp();
 114
 115         close(device_fd);
 116 }
 117
 118 bool read_packet(vpn_packet_t *packet)
 119 {
 120         int lenin;
 121
 122         cp();
 123
 124         switch(device_type) {
 125                 case DEVICE_TYPE_TUN:
 126                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 127
 128                         if(lenin <= 0) {
 129                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 130                                            device_info, device, strerror(errno));
 131                                 return false;
 132                         }
 133
 134                         packet->len = lenin + 10;
 135                         break;
 136                 case DEVICE_TYPE_TAP:
 137                         lenin = read(device_fd, packet->data, MTU);
 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;
 146                         break;
 147                 case DEVICE_TYPE_ETHERTAP:
 148                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 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 - 2;
 157                         break;
 158         }
 159
 160         device_total_in += packet->len;
 161
 162         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 163                            device_info);
 164
 165         return true;
 166 }
 167
 168 bool write_packet(vpn_packet_t *packet)
 169 {
 170         cp();
 171
 172         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 173                            packet->len, device_info);
 174
 175         switch(device_type) {
 176                 case DEVICE_TYPE_TUN:
 177                         packet->data[10] = packet->data[11] = 0;
 178                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 179                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 180                                            strerror(errno));
 181                                 return false;
 182                         }
 183                         break;
 184                 case DEVICE_TYPE_TAP:
 185                         if(write(device_fd, packet->data, packet->len) < 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_ETHERTAP:
 192                         *(short int *)(packet->data - 2) = packet->len;
 193
 194                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 195                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 196                                            strerror(errno));
 197                                 return false;
 198                         }
 199                         break;
 200         }
 201
 202         device_total_out += packet->len;
 203
 204         return true;
 205 }
 206
 207 void dump_device_stats(void)
 208 {
 209         cp();
 210
 211         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 212         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 213         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 214 }