git.meshlink.io Git - meshlink/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
  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         struct ifreq ifr;
  57
  58         cp();
  59
  60         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  61                 device = xstrdup(DEFAULT_DEVICE);
  62
  63         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  64 #ifdef HAVE_LINUX_IF_TUN_H
  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         cp();
 121
 122         close(device_fd);
 123
 124         free(device);
 125         free(iface);
 126 }
 127
 128 bool read_packet(vpn_packet_t *packet) {
 129         int inlen;
 130
 131         cp();
 132
 133         switch(device_type) {
 134                 case DEVICE_TYPE_TUN:
 135                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 136
 137                         if(inlen <= 0) {
 138                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 139                                            device_info, device, strerror(errno));
 140                                 return false;
 141                         }
 142
 143                         packet->len = inlen + 10;
 144                         break;
 145                 case DEVICE_TYPE_TAP:
 146                         inlen = read(device_fd, packet->data, MTU);
 147
 148                         if(inlen <= 0) {
 149                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 150                                            device_info, device, strerror(errno));
 151                                 return false;
 152                         }
 153
 154                         packet->len = inlen;
 155                         break;
 156                 case DEVICE_TYPE_ETHERTAP:
 157                         inlen = read(device_fd, packet->data - 2, MTU + 2);
 158
 159                         if(inlen <= 0) {
 160                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 161                                            device_info, device, strerror(errno));
 162                                 return false;
 163                         }
 164
 165                         packet->len = inlen - 2;
 166                         break;
 167         }
 168
 169         device_total_in += packet->len;
 170
 171         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 172                            device_info);
 173
 174         return true;
 175 }
 176
 177 bool write_packet(vpn_packet_t *packet) {
 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         cp();
 217
 218         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 219         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 220         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 221 }