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                   2001-2016 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 ENABLE_TUNEMU
  33 #include "tunemu.h"
  34 #endif
  35
  36 #define DEFAULT_TUN_DEVICE "/dev/tun0"
  37 #define DEFAULT_TAP_DEVICE "/dev/tap0"
  38
  39 typedef enum device_type {
  40         DEVICE_TYPE_TUN,
  41         DEVICE_TYPE_TUNIFHEAD,
  42         DEVICE_TYPE_TAP,
  43 #ifdef ENABLE_TUNEMU
  44         DEVICE_TYPE_TUNEMU,
  45 #endif
  46 } device_type_t;
  47
  48 int device_fd = -1;
  49 char *device = NULL;
  50 char *iface = NULL;
  51 static char *device_info = NULL;
  52 static uint64_t device_total_in = 0;
  53 static uint64_t device_total_out = 0;
  54 #if defined(ENABLE_TUNEMU)
  55 static device_type_t device_type = DEVICE_TYPE_TUNEMU;
  56 #elif defined(HAVE_OPENBSD) || defined(HAVE_FREEBSD) || defined(HAVE_DRAGONFLY)
  57 static device_type_t device_type = DEVICE_TYPE_TUNIFHEAD;
  58 #else
  59 static device_type_t device_type = DEVICE_TYPE_TUN;
  60 #endif
  61
  62 static bool setup_device(void) {
  63         // Find out which device file to open
  64
  65         if(!get_config_string(lookup_config(config_tree, "Device"), &device)) {
  66                 if(routing_mode == RMODE_ROUTER)
  67                         device = xstrdup(DEFAULT_TUN_DEVICE);
  68                 else
  69                         device = xstrdup(DEFAULT_TAP_DEVICE);
  70         }
  71
  72         // Find out if it's supposed to be a tun or a tap device
  73
  74         char *type;
  75
  76         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
  77                 if(!strcasecmp(type, "tun"))
  78                         /* use default */;
  79 #ifdef ENABLE_TUNEMU
  80                 else if(!strcasecmp(type, "tunemu"))
  81                         device_type = DEVICE_TYPE_TUNEMU;
  82 #endif
  83                 else if(!strcasecmp(type, "tunnohead"))
  84                         device_type = DEVICE_TYPE_TUN;
  85                 else if(!strcasecmp(type, "tunifhead"))
  86                         device_type = DEVICE_TYPE_TUNIFHEAD;
  87                 else if(!strcasecmp(type, "tap"))
  88                         device_type = DEVICE_TYPE_TAP;
  89                 else {
  90                         logger(LOG_ERR, "Unknown device type %s!", type);
  91                         return false;
  92                 }
  93         } else {
  94                 if(strstr(device, "tap") || routing_mode != RMODE_ROUTER)
  95                         device_type = DEVICE_TYPE_TAP;
  96         }
  97
  98         // Open the device
  99
 100         switch(device_type) {
 101 #ifdef ENABLE_TUNEMU
 102                 case DEVICE_TYPE_TUNEMU: {
 103                         char dynamic_name[256] = "";
 104                         device_fd = tunemu_open(dynamic_name);
 105                 }
 106                         break;
 107 #endif
 108                 default:
 109                         device_fd = open(device, O_RDWR | O_NONBLOCK);
 110         }
 111
 112         if(device_fd < 0) {
 113                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
 114                 return false;
 115         }
 116
 117 #ifdef FD_CLOEXEC
 118         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 119 #endif
 120
 121         // Guess what the corresponding interface is called
 122
 123         char *realname;
 124
 125 #if defined(HAVE_FDEVNAME)
 126         realname = fdevname(device_fd) ? : device;
 127 #elif defined(HAVE_DEVNAME)
 128         struct stat buf;
 129         if(!fstat(device_fd, &buf))
 130                 realname = devname(buf.st_rdev, S_IFCHR) ? : device;
 131 #else
 132         realname = device;
 133 #endif
 134
 135         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
 136                 iface = xstrdup(strrchr(realname, '/') ? strrchr(realname, '/') + 1 : realname);
 137         else if(strcmp(iface, strrchr(realname, '/') ? strrchr(realname, '/') + 1 : realname))
 138                 logger(LOG_WARNING, "Warning: Interface does not match Device. $INTERFACE might be set incorrectly.");
 139
 140         // Configure the device as best as we can
 141
 142         switch(device_type) {
 143                 default:
 144                         device_type = DEVICE_TYPE_TUN;
 145                 case DEVICE_TYPE_TUN:
 146 #ifdef TUNSIFHEAD
 147                 {
 148                         const int zero = 0;
 149                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 150                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 151                                 return false;
 152                         }
 153                 }
 154 #endif
 155 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 156                 {
 157                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 158                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 159                 }
 160 #endif
 161
 162                         device_info = "Generic BSD tun device";
 163                         break;
 164                 case DEVICE_TYPE_TUNIFHEAD:
 165 #ifdef TUNSIFHEAD
 166                 {
 167                         const int one = 1;
 168                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 169                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 170                                 return false;
 171                         }
 172                 }
 173 #endif
 174 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 175                 {
 176                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 177                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 178                 }
 179 #endif
 180
 181                         device_info = "Generic BSD tun device";
 182                         break;
 183                 case DEVICE_TYPE_TAP:
 184                         if(routing_mode == RMODE_ROUTER)
 185                                 overwrite_mac = true;
 186                         device_info = "Generic BSD tap device";
 187 #ifdef TAPGIFNAME
 188                         {
 189                                 struct ifreq ifr;
 190                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 191                                         if(iface)
 192                                                 free(iface);
 193                                         iface = xstrdup(ifr.ifr_name);
 194                                 }
 195                         }
 196
 197 #endif
 198                         break;
 199 #ifdef ENABLE_TUNEMU
 200                 case DEVICE_TYPE_TUNEMU:
 201                         device_info = "BSD tunemu device";
 202                         break;
 203 #endif
 204         }
 205
 206         logger(LOG_INFO, "%s is a %s", device, device_info);
 207
 208         return true;
 209 }
 210
 211 static void close_device(void) {
 212         switch(device_type) {
 213 #ifdef ENABLE_TUNEMU
 214                 case DEVICE_TYPE_TUNEMU:
 215                         tunemu_close(device_fd);
 216                         break;
 217 #endif
 218                 default:
 219                         close(device_fd);
 220         }
 221
 222         free(device);
 223         free(iface);
 224 }
 225
 226 static bool read_packet(vpn_packet_t *packet) {
 227         int lenin;
 228
 229         switch(device_type) {
 230                 case DEVICE_TYPE_TUN:
 231 #ifdef ENABLE_TUNEMU
 232                 case DEVICE_TYPE_TUNEMU:
 233                         if(device_type == DEVICE_TYPE_TUNEMU)
 234                                 lenin = tunemu_read(device_fd, packet->data + 14, MTU - 14);
 235                         else
 236 #endif
 237                                 lenin = read(device_fd, packet->data + 14, MTU - 14);
 238
 239                         if(lenin <= 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(packet->data[14] >> 4) {
 246                                 case 4:
 247                                         packet->data[12] = 0x08;
 248                                         packet->data[13] = 0x00;
 249                                         break;
 250                                 case 6:
 251                                         packet->data[12] = 0x86;
 252                                         packet->data[13] = 0xDD;
 253                                         break;
 254                                 default:
 255                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 256                                                            "Unknown IP version %d while reading packet from %s %s",
 257                                                            packet->data[14] >> 4, device_info, device);
 258                                         return false;
 259                         }
 260
 261                         memset(packet->data, 0, 12);
 262                         packet->len = lenin + 14;
 263                         break;
 264
 265                 case DEVICE_TYPE_TUNIFHEAD: {
 266                         u_int32_t type;
 267                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, MTU - 14}};
 268
 269                         if((lenin = readv(device_fd, vector, 2)) <= 0) {
 270                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 271                                            device, strerror(errno));
 272                                 return false;
 273                         }
 274
 275                         switch (ntohl(type)) {
 276                                 case AF_INET:
 277                                         packet->data[12] = 0x08;
 278                                         packet->data[13] = 0x00;
 279                                         break;
 280
 281                                 case AF_INET6:
 282                                         packet->data[12] = 0x86;
 283                                         packet->data[13] = 0xDD;
 284                                         break;
 285
 286                                 default:
 287                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 288                                                            "Unknown address family %x while reading packet from %s %s",
 289                                                            ntohl(type), device_info, device);
 290                                         return false;
 291                         }
 292
 293                         memset(packet->data, 0, 12);
 294                         packet->len = lenin + 10;
 295                         break;
 296                 }
 297
 298                 case DEVICE_TYPE_TAP:
 299                         if((lenin = read(device_fd, packet->data, MTU)) <= 0) {
 300                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 301                                            device, strerror(errno));
 302                                 return false;
 303                         }
 304
 305                         packet->len = lenin;
 306                         break;
 307
 308                 default:
 309                         return false;
 310         }
 311
 312         device_total_in += packet->len;
 313
 314         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s",
 315                            packet->len, device_info);
 316
 317         return true;
 318 }
 319
 320 static bool write_packet(vpn_packet_t *packet) {
 321         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 322                            packet->len, device_info);
 323
 324         switch(device_type) {
 325                 case DEVICE_TYPE_TUN:
 326                         if(write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 327                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 328                                            device, strerror(errno));
 329                                 return false;
 330                         }
 331                         break;
 332
 333                 case DEVICE_TYPE_TUNIFHEAD: {
 334                         u_int32_t type;
 335                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, packet->len - 14}};
 336                         int af;
 337
 338                         af = (packet->data[12] << 8) + packet->data[13];
 339
 340                         switch (af) {
 341                                 case 0x0800:
 342                                         type = htonl(AF_INET);
 343                                         break;
 344                                 case 0x86DD:
 345                                         type = htonl(AF_INET6);
 346                                         break;
 347                                 default:
 348                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 349                                                            "Unknown address family %x while writing packet to %s %s",
 350                                                            af, device_info, device);
 351                                         return false;
 352                         }
 353
 354                         if(writev(device_fd, vector, 2) < 0) {
 355                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 356                                            strerror(errno));
 357                                 return false;
 358                         }
 359                         break;
 360                 }
 361
 362                 case DEVICE_TYPE_TAP:
 363                         if(write(device_fd, packet->data, packet->len) < 0) {
 364                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 365                                            device, strerror(errno));
 366                                 return false;
 367                         }
 368                         break;
 369
 370 #ifdef ENABLE_TUNEMU
 371                 case DEVICE_TYPE_TUNEMU:
 372                         if(tunemu_write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 373                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 374                                            device, strerror(errno));
 375                                 return false;
 376                         }
 377                         break;
 378 #endif
 379
 380                 default:
 381                         return false;
 382         }
 383
 384         device_total_out += packet->len;
 385
 386         return true;
 387 }
 388
 389 static void dump_device_stats(void) {
 390         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 391         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 392         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 393 }
 394
 395 const devops_t os_devops = {
 396         .setup = setup_device,
 397         .close = close_device,
 398         .read = read_packet,
 399         .write = write_packet,
 400         .dump_stats = dump_device_stats,
 401 };