tinc-vpn.org Git - tinc/blob - src/bsd/device.c

   1 /*
   2     device.c -- Interaction BSD tun/tap device
   3     Copyright (C) 2001-2005 Ivo Timmermans,
   4                   2001-2012 Guus Sliepen <guus@tinc-vpn.org>
   5                   2009      Grzegorz Dymarek <gregd72002@googlemail.com>
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20 */
  21
  22 #include "system.h"
  23
  24 #include "conf.h"
  25 #include "device.h"
  26 #include "logger.h"
  27 #include "net.h"
  28 #include "route.h"
  29 #include "utils.h"
  30 #include "xalloc.h"
  31
  32 #ifdef HAVE_TUNEMU
  33 #include "bsd/tunemu.h"
  34 #endif
  35
  36 #define DEFAULT_DEVICE "/dev/tun0"
  37
  38 typedef enum device_type {
  39         DEVICE_TYPE_TUN,
  40         DEVICE_TYPE_TUNIFHEAD,
  41         DEVICE_TYPE_TAP,
  42 #ifdef HAVE_TUNEMU
  43         DEVICE_TYPE_TUNEMU,
  44 #endif
  45 } device_type_t;
  46
  47 int device_fd = -1;
  48 char *device = NULL;
  49 char *iface = NULL;
  50 static char *device_info = NULL;
  51 static uint64_t device_total_in = 0;
  52 static uint64_t device_total_out = 0;
  53 #if defined(TUNEMU)
  54 static device_type_t device_type = DEVICE_TYPE_TUNEMU;
  55 #elif defined(HAVE_OPENBSD) || defined(HAVE_FREEBSD) || defined(HAVE_DRAGONFLY)
  56 static device_type_t device_type = DEVICE_TYPE_TUNIFHEAD;
  57 #else
  58 static device_type_t device_type = DEVICE_TYPE_TUN;
  59 #endif
  60
  61 static bool setup_device(void) {
  62         char *type;
  63
  64         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  65                 device = xstrdup(DEFAULT_DEVICE);
  66
  67         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  68                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  69
  70         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
  71                 if(!strcasecmp(type, "tun"))
  72                         /* use default */;
  73 #ifdef HAVE_TUNEMU
  74                 else if(!strcasecmp(type, "tunemu"))
  75                         device_type = DEVICE_TYPE_TUNEMU;
  76 #endif
  77                 else if(!strcasecmp(type, "tunnohead"))
  78                         device_type = DEVICE_TYPE_TUN;
  79                 else if(!strcasecmp(type, "tunifhead"))
  80                         device_type = DEVICE_TYPE_TUNIFHEAD;
  81                 else if(!strcasecmp(type, "tap"))
  82                         device_type = DEVICE_TYPE_TAP;
  83                 else {
  84                         logger(LOG_ERR, "Unknown device type %s!", type);
  85                         return false;
  86                 }
  87         } else {
  88                 if(strstr(device, "tap") || routing_mode != RMODE_ROUTER)
  89                         device_type = DEVICE_TYPE_TAP;
  90         }
  91
  92         switch(device_type) {
  93 #ifdef HAVE_TUNEMU
  94                 case DEVICE_TYPE_TUNEMU: {
  95                         char dynamic_name[256] = "";
  96                         device_fd = tunemu_open(dynamic_name);
  97                 }
  98                         break;
  99 #endif
 100                 default:
 101                         device_fd = open(device, O_RDWR | O_NONBLOCK);
 102         }
 103
 104         if(device_fd < 0) {
 105                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
 106                 return false;
 107         }
 108
 109 #ifdef FD_CLOEXEC
 110         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 111 #endif
 112
 113         switch(device_type) {
 114                 default:
 115                         device_type = DEVICE_TYPE_TUN;
 116                 case DEVICE_TYPE_TUN:
 117 #ifdef TUNSIFHEAD
 118                 {
 119                         const int zero = 0;
 120                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 121                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 122                                 return false;
 123                         }
 124                 }
 125 #endif
 126 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 127                 {
 128                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 129                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 130                 }
 131 #endif
 132
 133                         device_info = "Generic BSD tun device";
 134                         break;
 135                 case DEVICE_TYPE_TUNIFHEAD:
 136 #ifdef TUNSIFHEAD
 137                 {
 138                         const int one = 1;
 139                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 140                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 141                                 return false;
 142                         }
 143                 }
 144 #endif
 145 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 146                 {
 147                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 148                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 149                 }
 150 #endif
 151
 152                         device_info = "Generic BSD tun device";
 153                         break;
 154                 case DEVICE_TYPE_TAP:
 155                         if(routing_mode == RMODE_ROUTER)
 156                                 overwrite_mac = true;
 157                         device_info = "Generic BSD tap device";
 158 #ifdef TAPGIFNAME
 159                         {
 160                                 struct ifreq ifr;
 161                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 162                                         if(iface)
 163                                                 free(iface);
 164                                         iface = xstrdup(ifr.ifr_name);
 165                                 }
 166                         }
 167
 168 #endif
 169                         break;
 170 #ifdef HAVE_TUNEMU
 171                 case DEVICE_TYPE_TUNEMU:
 172                         device_info = "BSD tunemu device";
 173                         break;
 174 #endif
 175         }
 176
 177         logger(LOG_INFO, "%s is a %s", device, device_info);
 178
 179         return true;
 180 }
 181
 182 static void close_device(void) {
 183         switch(device_type) {
 184 #ifdef HAVE_TUNEMU
 185                 case DEVICE_TYPE_TUNEMU:
 186                         tunemu_close(device_fd);
 187                         break;
 188 #endif
 189                 default:
 190                         close(device_fd);
 191         }
 192
 193         free(device);
 194         free(iface);
 195 }
 196
 197 static bool read_packet(vpn_packet_t *packet) {
 198         int lenin;
 199
 200         switch(device_type) {
 201                 case DEVICE_TYPE_TUN:
 202 #ifdef HAVE_TUNEMU
 203                 case DEVICE_TYPE_TUNEMU:
 204                         if(device_type == DEVICE_TYPE_TUNEMU)
 205                                 lenin = tunemu_read(device_fd, packet->data + 14, MTU - 14);
 206                         else
 207 #endif
 208                                 lenin = read(device_fd, packet->data + 14, MTU - 14);
 209
 210                         if(lenin <= 0) {
 211                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 212                                            device, strerror(errno));
 213                                 return false;
 214                         }
 215
 216                         switch(packet->data[14] >> 4) {
 217                                 case 4:
 218                                         packet->data[12] = 0x08;
 219                                         packet->data[13] = 0x00;
 220                                         break;
 221                                 case 6:
 222                                         packet->data[12] = 0x86;
 223                                         packet->data[13] = 0xDD;
 224                                         break;
 225                                 default:
 226                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 227                                                            "Unknown IP version %d while reading packet from %s %s",
 228                                                            packet->data[14] >> 4, device_info, device);
 229                                         return false;
 230                         }
 231
 232                         packet->len = lenin + 14;
 233                         break;
 234
 235                 case DEVICE_TYPE_TUNIFHEAD: {
 236                         u_int32_t type;
 237                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, MTU - 14}};
 238
 239                         if((lenin = readv(device_fd, vector, 2)) <= 0) {
 240                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 241                                            device, strerror(errno));
 242                                 return false;
 243                         }
 244
 245                         switch (ntohl(type)) {
 246                                 case AF_INET:
 247                                         packet->data[12] = 0x08;
 248                                         packet->data[13] = 0x00;
 249                                         break;
 250
 251                                 case AF_INET6:
 252                                         packet->data[12] = 0x86;
 253                                         packet->data[13] = 0xDD;
 254                                         break;
 255
 256                                 default:
 257                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 258                                                            "Unknown address family %x while reading packet from %s %s",
 259                                                            ntohl(type), device_info, device);
 260                                         return false;
 261                         }
 262
 263                         packet->len = lenin + 10;
 264                         break;
 265                 }
 266
 267                 case DEVICE_TYPE_TAP:
 268                         if((lenin = read(device_fd, packet->data, MTU)) <= 0) {
 269                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 270                                            device, strerror(errno));
 271                                 return false;
 272                         }
 273
 274                         packet->len = lenin;
 275                         break;
 276
 277                 default:
 278                         return false;
 279         }
 280
 281         device_total_in += packet->len;
 282
 283         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s",
 284                            packet->len, device_info);
 285
 286         return true;
 287 }
 288
 289 static bool write_packet(vpn_packet_t *packet) {
 290         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 291                            packet->len, device_info);
 292
 293         switch(device_type) {
 294                 case DEVICE_TYPE_TUN:
 295                         if(write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 296                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 297                                            device, strerror(errno));
 298                                 return false;
 299                         }
 300                         break;
 301
 302                 case DEVICE_TYPE_TUNIFHEAD: {
 303                         u_int32_t type;
 304                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, packet->len - 14}};
 305                         int af;
 306
 307                         af = (packet->data[12] << 8) + packet->data[13];
 308
 309                         switch (af) {
 310                                 case 0x0800:
 311                                         type = htonl(AF_INET);
 312                                         break;
 313                                 case 0x86DD:
 314                                         type = htonl(AF_INET6);
 315                                         break;
 316                                 default:
 317                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 318                                                            "Unknown address family %x while writing packet to %s %s",
 319                                                            af, device_info, device);
 320                                         return false;
 321                         }
 322
 323                         if(writev(device_fd, vector, 2) < 0) {
 324                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 325                                            strerror(errno));
 326                                 return false;
 327                         }
 328                         break;
 329                 }
 330
 331                 case DEVICE_TYPE_TAP:
 332                         if(write(device_fd, packet->data, packet->len) < 0) {
 333                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 334                                            device, strerror(errno));
 335                                 return false;
 336                         }
 337                         break;
 338
 339 #ifdef HAVE_TUNEMU
 340                 case DEVICE_TYPE_TUNEMU:
 341                         if(tunemu_write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 342                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 343                                            device, strerror(errno));
 344                                 return false;
 345                         }
 346                         break;
 347 #endif
 348
 349                 default:
 350                         return false;
 351         }
 352
 353         device_total_out += packet->len;
 354
 355         return true;
 356 }
 357
 358 static void dump_device_stats(void) {
 359         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 360         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 361         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 362 }
 363
 364 const devops_t os_devops = {
 365         .setup = setup_device,
 366         .close = close_device,
 367         .read = read_packet,
 368         .write = write_packet,
 369         .dump_stats = dump_device_stats,
 370 };