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 #ifdef HAVE_LINUX_IF_TUN_H
  24 #include <linux/if_tun.h>
  25 #define DEFAULT_DEVICE "/dev/net/tun"
  26 #else
  27 #define DEFAULT_DEVICE "/dev/tap0"
  28 #endif
  29
  30 #include "conf.h"
  31 #include "device.h"
  32 #include "logger.h"
  33 #include "net.h"
  34 #include "route.h"
  35 #include "threads.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 int fd = -1;
  47 static device_type_t device_type;
  48 char *device = NULL;
  49 char *iface = NULL;
  50 static char ifrname[IFNAMSIZ];
  51 static char *device_info;
  52
  53 static uint64_t device_total_in = 0;
  54 static uint64_t device_total_out = 0;
  55
  56 thread_t thread;
  57
  58 static void read_thread(void *arg) {
  59         static vpn_packet_t packet;
  60         errno = 0;
  61
  62         while(true) {
  63                 if(read_packet(&packet)) {
  64                         route(myself, &packet);
  65                 } else {
  66                         if(errno == EAGAIN || errno == EINTR) {
  67                                 errno = 0;
  68                                 continue;
  69                         }
  70
  71                         return;
  72                 }
  73         }
  74 }
  75
  76 bool setup_device(void) {
  77         struct ifreq ifr;
  78         bool t1q = false;
  79
  80         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  81                 device = xstrdup(DEFAULT_DEVICE);
  82
  83         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  84 #ifdef HAVE_LINUX_IF_TUN_H
  85                 if (netname != NULL)
  86                         iface = xstrdup(netname);
  87 #else
  88                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  89 #endif
  90         fd = open(device, O_RDWR);
  91
  92         if(fd < 0) {
  93                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  94                 return false;
  95         }
  96
  97 #ifdef HAVE_LINUX_IF_TUN_H
  98         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  99
 100         memset(&ifr, 0, sizeof ifr);
 101         if(routing_mode == RMODE_ROUTER) {
 102                 ifr.ifr_flags = IFF_TUN;
 103                 device_type = DEVICE_TYPE_TUN;
 104                 device_info = "Linux tun/tap device (tun mode)";
 105         } else {
 106                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 107                 device_type = DEVICE_TYPE_TAP;
 108                 device_info = "Linux tun/tap device (tap mode)";
 109         }
 110
 111 #ifdef IFF_ONE_QUEUE
 112         /* Set IFF_ONE_QUEUE flag... */
 113         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
 114                 ifr.ifr_flags |= IFF_ONE_QUEUE;
 115 #endif
 116
 117         if(iface)
 118                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
 119
 120         if(!ioctl(fd, TUNSETIFF, &ifr)) {
 121                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 122                 if(iface) free(iface);
 123                 iface = xstrdup(ifrname);
 124         } else if(!ioctl(fd, (('T' << 8) | 202), &ifr)) {
 125                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
 126                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 127                 if(iface) free(iface);
 128                 iface = xstrdup(ifrname);
 129         } else
 130 #endif
 131         {
 132                 if(routing_mode == RMODE_ROUTER)
 133                         overwrite_mac = true;
 134                 device_info = "Linux ethertap device";
 135                 device_type = DEVICE_TYPE_ETHERTAP;
 136                 if(iface)
 137                         free(iface);
 138                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
 139         }
 140
 141         logger(LOG_INFO, "%s is a %s", device, device_info);
 142
 143         return thread_create(&thread, read_thread, NULL);
 144 }
 145
 146 void close_device(void) {
 147         close(fd);
 148         thread_destroy(&thread);
 149
 150         free(device);
 151         free(iface);
 152 }
 153
 154 bool read_packet(vpn_packet_t *packet) {
 155         int inlen;
 156
 157         switch(device_type) {
 158                 case DEVICE_TYPE_TUN:
 159                         inlen = read(fd, packet->data + 10, MTU - 10);
 160
 161                         if(inlen <= 0) {
 162                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 163                                            device_info, device, strerror(errno));
 164                                 return false;
 165                         }
 166
 167                         packet->len = inlen + 10;
 168                         break;
 169                 case DEVICE_TYPE_TAP:
 170                         inlen = read(fd, packet->data, MTU);
 171
 172                         if(inlen <= 0) {
 173                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 174                                            device_info, device, strerror(errno));
 175                                 return false;
 176                         }
 177
 178                         packet->len = inlen;
 179                         break;
 180                 case DEVICE_TYPE_ETHERTAP:
 181                         inlen = read(fd, packet->data - 2, MTU + 2);
 182
 183                         if(inlen <= 0) {
 184                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 185                                            device_info, device, strerror(errno));
 186                                 return false;
 187                         }
 188
 189                         packet->len = inlen - 2;
 190                         break;
 191         }
 192
 193         device_total_in += packet->len;
 194
 195         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 196                            device_info);
 197
 198         return true;
 199 }
 200
 201 bool write_packet(vpn_packet_t *packet) {
 202         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 203                            packet->len, device_info);
 204
 205         switch(device_type) {
 206                 case DEVICE_TYPE_TUN:
 207                         packet->data[10] = packet->data[11] = 0;
 208                         if(write(fd, packet->data + 10, packet->len - 10) < 0) {
 209                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 210                                            strerror(errno));
 211                                 return false;
 212                         }
 213                         break;
 214                 case DEVICE_TYPE_TAP:
 215                         if(write(fd, packet->data, packet->len) < 0) {
 216                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 217                                            strerror(errno));
 218                                 return false;
 219                         }
 220                         break;
 221                 case DEVICE_TYPE_ETHERTAP:
 222                         *(short int *)(packet->data - 2) = packet->len;
 223
 224                         if(write(fd, packet->data - 2, packet->len + 2) < 0) {
 225                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 226                                            strerror(errno));
 227                                 return false;
 228                         }
 229                         break;
 230         }
 231
 232         device_total_out += packet->len;
 233
 234         return true;
 235 }
 236
 237 void dump_device_stats(void) {
 238         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 239         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 240         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 241 }