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 "device.h"
  28 #include "logger.h"
  29 #include "net.h"
  30 #include "route.h"
  31 #include "utils.h"
  32 #include "xalloc.h"
  33 #include "device.h"
  34
  35 typedef enum device_type_t {
  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 = NULL;
  43 char *iface = NULL;
  44 static char ifrname[IFNAMSIZ];
  45 static char *device_info;
  46
  47 uint64_t device_in_packets = 0;
  48 uint64_t device_in_bytes = 0;
  49 uint64_t device_out_packets = 0;
  50 uint64_t device_out_bytes = 0;
  51
  52 bool setup_device(void) {
  53         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  54                 device = xstrdup(DEFAULT_DEVICE);
  55
  56         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  57 #ifdef HAVE_LINUX_IF_TUN_H
  58                 if (netname != NULL)
  59                         iface = xstrdup(netname);
  60 #else
  61                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  62 #endif
  63         device_fd = open(device, O_RDWR | O_NONBLOCK);
  64
  65         if(device_fd < 0) {
  66                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  67                 return false;
  68         }
  69
  70         struct ifreq ifr = {{{0}}};
  71
  72         if(routing_mode == RMODE_ROUTER) {
  73                 ifr.ifr_flags = IFF_TUN;
  74                 device_type = DEVICE_TYPE_TUN;
  75                 device_info = "Linux tun/tap device (tun mode)";
  76         } else {
  77                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  78                 device_type = DEVICE_TYPE_TAP;
  79                 device_info = "Linux tun/tap device (tap mode)";
  80         }
  81
  82 #ifdef IFF_ONE_QUEUE
  83         /* Set IFF_ONE_QUEUE flag... */
  84
  85         bool t1q = false;
  86         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  87                 ifr.ifr_flags |= IFF_ONE_QUEUE;
  88 #endif
  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         }
 103
 104         logger(LOG_INFO, "%s is a %s", device, device_info);
 105
 106         return true;
 107 }
 108
 109 void close_device(void) {
 110         close(device_fd);
 111
 112         free(device);
 113         free(iface);
 114 }
 115
 116 bool read_packet(vpn_packet_t *packet) {
 117         int inlen;
 118
 119         switch(device_type) {
 120                 case DEVICE_TYPE_TUN:
 121                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 122
 123                         if(inlen <= 0) {
 124                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 125                                            device_info, device, strerror(errno));
 126                                 return false;
 127                         }
 128
 129                         packet->len = inlen + 10;
 130                         break;
 131                 case DEVICE_TYPE_TAP:
 132                         inlen = read(device_fd, packet->data, MTU);
 133
 134                         if(inlen <= 0) {
 135                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 136                                            device_info, device, strerror(errno));
 137                                 return false;
 138                         }
 139
 140                         packet->len = inlen;
 141                         break;
 142                 default:
 143                         abort();
 144         }
 145
 146         device_in_packets++;
 147         device_in_bytes += packet->len;
 148
 149         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 150                            device_info);
 151
 152         return true;
 153 }
 154
 155 bool write_packet(vpn_packet_t *packet) {
 156         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 157                            packet->len, device_info);
 158
 159         switch(device_type) {
 160                 case DEVICE_TYPE_TUN:
 161                         packet->data[10] = packet->data[11] = 0;
 162                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 163                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 164                                            strerror(errno));
 165                                 return false;
 166                         }
 167                         break;
 168                 case DEVICE_TYPE_TAP:
 169                         if(write(device_fd, packet->data, packet->len) < 0) {
 170                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 171                                            strerror(errno));
 172                                 return false;
 173                         }
 174                         break;
 175                 default:
 176                         abort();
 177         }
 178
 179         device_out_packets++;
 180         device_out_bytes += packet->len;
 181
 182         return true;
 183 }
 184
 185 void dump_device_stats(void) {
 186         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 187         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
 188         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
 189 }