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                   2001-2014 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 #if defined(HAVE_FREEBSD) || defined(HAVE_NETBSD) || defined(HAVE_DARWIN)
  38 #define DEFAULT_TAP_DEVICE "/dev/tap0"
  39 #else
  40 #define DEFAULT_TAP_DEVICE "/dev/tun0"
  41 #endif
  42
  43 typedef enum device_type {
  44         DEVICE_TYPE_TUN,
  45         DEVICE_TYPE_TUNIFHEAD,
  46         DEVICE_TYPE_TAP,
  47 #ifdef ENABLE_TUNEMU
  48         DEVICE_TYPE_TUNEMU,
  49 #endif
  50 } device_type_t;
  51
  52 int device_fd = -1;
  53 char *device = NULL;
  54 char *iface = NULL;
  55 static char *device_info = NULL;
  56 static uint64_t device_total_in = 0;
  57 static uint64_t device_total_out = 0;
  58 #if defined(ENABLE_TUNEMU)
  59 static device_type_t device_type = DEVICE_TYPE_TUNEMU;
  60 #elif defined(HAVE_OPENBSD) || defined(HAVE_FREEBSD) || defined(HAVE_DRAGONFLY)
  61 static device_type_t device_type = DEVICE_TYPE_TUNIFHEAD;
  62 #else
  63 static device_type_t device_type = DEVICE_TYPE_TUN;
  64 #endif
  65
  66 static bool setup_device(void) {
  67         char *type;
  68
  69         if(!get_config_string(lookup_config(config_tree, "Device"), &device)) {
  70                 if(routing_mode == RMODE_ROUTER)
  71                         device = xstrdup(DEFAULT_TUN_DEVICE);
  72                 else
  73                         device = xstrdup(DEFAULT_TAP_DEVICE);
  74         }
  75
  76         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  77                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  78         else if(strcmp(iface, strrchr(device, '/') ? strrchr(device, '/') + 1 : device))
  79                 logger(LOG_WARNING, "Warning: Interface does not match Device. $INTERFACE might be set incorrectly.");
  80
  81         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
  82                 if(!strcasecmp(type, "tun"))
  83                         /* use default */;
  84 #ifdef ENABLE_TUNEMU
  85                 else if(!strcasecmp(type, "tunemu"))
  86                         device_type = DEVICE_TYPE_TUNEMU;
  87 #endif
  88                 else if(!strcasecmp(type, "tunnohead"))
  89                         device_type = DEVICE_TYPE_TUN;
  90                 else if(!strcasecmp(type, "tunifhead"))
  91                         device_type = DEVICE_TYPE_TUNIFHEAD;
  92                 else if(!strcasecmp(type, "tap"))
  93                         device_type = DEVICE_TYPE_TAP;
  94                 else {
  95                         logger(LOG_ERR, "Unknown device type %s!", type);
  96                         return false;
  97                 }
  98         } else {
  99                 if(strstr(device, "tap") || routing_mode != RMODE_ROUTER)
 100                         device_type = DEVICE_TYPE_TAP;
 101         }
 102
 103         switch(device_type) {
 104 #ifdef ENABLE_TUNEMU
 105                 case DEVICE_TYPE_TUNEMU: {
 106                         char dynamic_name[256] = "";
 107                         device_fd = tunemu_open(dynamic_name);
 108                 }
 109                         break;
 110 #endif
 111                 default:
 112                         device_fd = open(device, O_RDWR | O_NONBLOCK);
 113         }
 114
 115         if(device_fd < 0) {
 116                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
 117                 return false;
 118         }
 119
 120 #ifdef FD_CLOEXEC
 121         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 122 #endif
 123
 124         switch(device_type) {
 125                 default:
 126                         device_type = DEVICE_TYPE_TUN;
 127                 case DEVICE_TYPE_TUN:
 128 #ifdef TUNSIFHEAD
 129                 {
 130                         const int zero = 0;
 131                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 132                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 133                                 return false;
 134                         }
 135                 }
 136 #endif
 137 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 138                 {
 139                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 140                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 141                 }
 142 #endif
 143
 144                         device_info = "Generic BSD tun device";
 145                         break;
 146                 case DEVICE_TYPE_TUNIFHEAD:
 147 #ifdef TUNSIFHEAD
 148                 {
 149                         const int one = 1;
 150                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 151                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 152                                 return false;
 153                         }
 154                 }
 155 #endif
 156 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 157                 {
 158                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 159                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 160                 }
 161 #endif
 162
 163                         device_info = "Generic BSD tun device";
 164                         break;
 165                 case DEVICE_TYPE_TAP:
 166                         if(routing_mode == RMODE_ROUTER)
 167                                 overwrite_mac = true;
 168                         device_info = "Generic BSD tap device";
 169 #ifdef TAPGIFNAME
 170                         {
 171                                 struct ifreq ifr;
 172                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 173                                         if(iface)
 174                                                 free(iface);
 175                                         iface = xstrdup(ifr.ifr_name);
 176                                 }
 177                         }
 178
 179 #endif
 180                         break;
 181 #ifdef ENABLE_TUNEMU
 182                 case DEVICE_TYPE_TUNEMU:
 183                         device_info = "BSD tunemu device";
 184                         break;
 185 #endif
 186         }
 187
 188         logger(LOG_INFO, "%s is a %s", device, device_info);
 189
 190         return true;
 191 }
 192
 193 static void close_device(void) {
 194         switch(device_type) {
 195 #ifdef ENABLE_TUNEMU
 196                 case DEVICE_TYPE_TUNEMU:
 197                         tunemu_close(device_fd);
 198                         break;
 199 #endif
 200                 default:
 201                         close(device_fd);
 202         }
 203
 204         free(device);
 205         free(iface);
 206 }
 207
 208 static bool read_packet(vpn_packet_t *packet) {
 209         int lenin;
 210
 211         switch(device_type) {
 212                 case DEVICE_TYPE_TUN:
 213 #ifdef ENABLE_TUNEMU
 214                 case DEVICE_TYPE_TUNEMU:
 215                         if(device_type == DEVICE_TYPE_TUNEMU)
 216                                 lenin = tunemu_read(device_fd, packet->data + 14, MTU - 14);
 217                         else
 218 #endif
 219                                 lenin = read(device_fd, packet->data + 14, MTU - 14);
 220
 221                         if(lenin <= 0) {
 222                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 223                                            device, strerror(errno));
 224                                 return false;
 225                         }
 226
 227                         switch(packet->data[14] >> 4) {
 228                                 case 4:
 229                                         packet->data[12] = 0x08;
 230                                         packet->data[13] = 0x00;
 231                                         break;
 232                                 case 6:
 233                                         packet->data[12] = 0x86;
 234                                         packet->data[13] = 0xDD;
 235                                         break;
 236                                 default:
 237                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 238                                                            "Unknown IP version %d while reading packet from %s %s",
 239                                                            packet->data[14] >> 4, device_info, device);
 240                                         return false;
 241                         }
 242
 243                         memset(packet->data, 0, 12);
 244                         packet->len = lenin + 14;
 245                         break;
 246
 247                 case DEVICE_TYPE_TUNIFHEAD: {
 248                         u_int32_t type;
 249                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, MTU - 14}};
 250
 251                         if((lenin = readv(device_fd, vector, 2)) <= 0) {
 252                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 253                                            device, strerror(errno));
 254                                 return false;
 255                         }
 256
 257                         switch (ntohl(type)) {
 258                                 case AF_INET:
 259                                         packet->data[12] = 0x08;
 260                                         packet->data[13] = 0x00;
 261                                         break;
 262
 263                                 case AF_INET6:
 264                                         packet->data[12] = 0x86;
 265                                         packet->data[13] = 0xDD;
 266                                         break;
 267
 268                                 default:
 269                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 270                                                            "Unknown address family %x while reading packet from %s %s",
 271                                                            ntohl(type), device_info, device);
 272                                         return false;
 273                         }
 274
 275                         memset(packet->data, 0, 12);
 276                         packet->len = lenin + 10;
 277                         break;
 278                 }
 279
 280                 case DEVICE_TYPE_TAP:
 281                         if((lenin = read(device_fd, packet->data, MTU)) <= 0) {
 282                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 283                                            device, strerror(errno));
 284                                 return false;
 285                         }
 286
 287                         packet->len = lenin;
 288                         break;
 289
 290                 default:
 291                         return false;
 292         }
 293
 294         device_total_in += packet->len;
 295
 296         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s",
 297                            packet->len, device_info);
 298
 299         return true;
 300 }
 301
 302 static bool write_packet(vpn_packet_t *packet) {
 303         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 304                            packet->len, device_info);
 305
 306         switch(device_type) {
 307                 case DEVICE_TYPE_TUN:
 308                         if(write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 309                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 310                                            device, strerror(errno));
 311                                 return false;
 312                         }
 313                         break;
 314
 315                 case DEVICE_TYPE_TUNIFHEAD: {
 316                         u_int32_t type;
 317                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, packet->len - 14}};
 318                         int af;
 319
 320                         af = (packet->data[12] << 8) + packet->data[13];
 321
 322                         switch (af) {
 323                                 case 0x0800:
 324                                         type = htonl(AF_INET);
 325                                         break;
 326                                 case 0x86DD:
 327                                         type = htonl(AF_INET6);
 328                                         break;
 329                                 default:
 330                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 331                                                            "Unknown address family %x while writing packet to %s %s",
 332                                                            af, device_info, device);
 333                                         return false;
 334                         }
 335
 336                         if(writev(device_fd, vector, 2) < 0) {
 337                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 338                                            strerror(errno));
 339                                 return false;
 340                         }
 341                         break;
 342                 }
 343
 344                 case DEVICE_TYPE_TAP:
 345                         if(write(device_fd, packet->data, packet->len) < 0) {
 346                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 347                                            device, strerror(errno));
 348                                 return false;
 349                         }
 350                         break;
 351
 352 #ifdef ENABLE_TUNEMU
 353                 case DEVICE_TYPE_TUNEMU:
 354                         if(tunemu_write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 355                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 356                                            device, strerror(errno));
 357                                 return false;
 358                         }
 359                         break;
 360 #endif
 361
 362                 default:
 363                         return false;
 364         }
 365
 366         device_total_out += packet->len;
 367
 368         return true;
 369 }
 370
 371 static void dump_device_stats(void) {
 372         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 373         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 374         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 375 }
 376
 377 const devops_t os_devops = {
 378         .setup = setup_device,
 379         .close = close_device,
 380         .read = read_packet,
 381         .write = write_packet,
 382         .dump_stats = dump_device_stats,
 383 };