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 #include <linux/if_tun.h>
  24 #define DEFAULT_DEVICE "/dev/net/tun"
  25
  26 #include "conf.h"
  27 #include "logger.h"
  28 #include "net.h"
  29 #include "route.h"
  30 #include "utils.h"
  31 #include "xalloc.h"
  32 #include "device.h"
  33
  34 typedef enum device_type_t {
  35         DEVICE_TYPE_TUN,
  36         DEVICE_TYPE_TAP,
  37 } device_type_t;
  38
  39 int device_fd = -1;
  40 static device_type_t device_type;
  41 char *device = NULL;
  42 char *iface = NULL;
  43 static char ifrname[IFNAMSIZ];
  44 static char *device_info;
  45
  46 uint64_t device_in_packets = 0;
  47 uint64_t device_in_bytes = 0;
  48 uint64_t device_out_packets = 0;
  49 uint64_t device_out_bytes = 0;
  50
  51 bool setup_device(void) {
  52         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  53                 device = xstrdup(DEFAULT_DEVICE);
  54
  55         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  56 #ifdef HAVE_LINUX_IF_TUN_H
  57                 if (netname != NULL)
  58                         iface = xstrdup(netname);
  59 #else
  60                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  61 #endif
  62         device_fd = open(device, O_RDWR | O_NONBLOCK);
  63
  64         if(device_fd < 0) {
  65                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  66                 return false;
  67         }
  68
  69         struct ifreq ifr = {{{0}}};
  70
  71         if(routing_mode == RMODE_ROUTER) {
  72                 ifr.ifr_flags = IFF_TUN;
  73                 device_type = DEVICE_TYPE_TUN;
  74                 device_info = "Linux tun/tap device (tun mode)";
  75         } else {
  76                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  77                 device_type = DEVICE_TYPE_TAP;
  78                 device_info = "Linux tun/tap device (tap mode)";
  79         }
  80
  81 #ifdef IFF_ONE_QUEUE
  82         /* Set IFF_ONE_QUEUE flag... */
  83
  84         bool t1q = false;
  85         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  86                 ifr.ifr_flags |= IFF_ONE_QUEUE;
  87 #endif
  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         }
 102
 103         logger(LOG_INFO, "%s is a %s", device, device_info);
 104
 105         return true;
 106 }
 107
 108 void close_device(void) {
 109         close(device_fd);
 110
 111         free(device);
 112         free(iface);
 113 }
 114
 115 bool read_packet(vpn_packet_t *packet) {
 116         int inlen;
 117
 118         switch(device_type) {
 119                 case DEVICE_TYPE_TUN:
 120                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 121
 122                         if(inlen <= 0) {
 123                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 124                                            device_info, device, strerror(errno));
 125                                 return false;
 126                         }
 127
 128                         packet->len = inlen + 10;
 129                         break;
 130                 case DEVICE_TYPE_TAP:
 131                         inlen = read(device_fd, packet->data, MTU);
 132
 133                         if(inlen <= 0) {
 134                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 135                                            device_info, device, strerror(errno));
 136                                 return false;
 137                         }
 138
 139                         packet->len = inlen;
 140                         break;
 141                 default:
 142                         abort();
 143         }
 144
 145         device_in_packets++;
 146         device_in_bytes += packet->len;
 147
 148         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 149                            device_info);
 150
 151         return true;
 152 }
 153
 154 bool write_packet(vpn_packet_t *packet) {
 155         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 156                            packet->len, device_info);
 157
 158         switch(device_type) {
 159                 case DEVICE_TYPE_TUN:
 160                         packet->data[10] = packet->data[11] = 0;
 161                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 162                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 163                                            strerror(errno));
 164                                 return false;
 165                         }
 166                         break;
 167                 case DEVICE_TYPE_TAP:
 168                         if(write(device_fd, packet->data, packet->len) < 0) {
 169                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 170                                            strerror(errno));
 171                                 return false;
 172                         }
 173                         break;
 174                 default:
 175                         abort();
 176         }
 177
 178         device_out_packets++;
 179         device_out_bytes += packet->len;
 180
 181         return true;
 182 }
 183
 184 void dump_device_stats(void) {
 185         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 186         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
 187         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
 188 }