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