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_TUN_DEVICE "/dev/tun0"
  37 #if defined(HAVE_FREEBSD) || defined(HAVE_NETBSD)
  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 HAVE_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(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
  79         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
  80                 if(!strcasecmp(type, "tun"))
  81                         /* use default */;
  82 #ifdef HAVE_TUNEMU
  83                 else if(!strcasecmp(type, "tunemu"))
  84                         device_type = DEVICE_TYPE_TUNEMU;
  85 #endif
  86                 else if(!strcasecmp(type, "tunnohead"))
  87                         device_type = DEVICE_TYPE_TUN;
  88                 else if(!strcasecmp(type, "tunifhead"))
  89                         device_type = DEVICE_TYPE_TUNIFHEAD;
  90                 else if(!strcasecmp(type, "tap"))
  91                         device_type = DEVICE_TYPE_TAP;
  92                 else {
  93                         logger(LOG_ERR, "Unknown device type %s!", type);
  94                         return false;
  95                 }
  96         } else {
  97                 if(strstr(device, "tap") || routing_mode != RMODE_ROUTER)
  98                         device_type = DEVICE_TYPE_TAP;
  99         }
 100
 101         switch(device_type) {
 102 #ifdef HAVE_TUNEMU
 103                 case DEVICE_TYPE_TUNEMU: {
 104                         char dynamic_name[256] = "";
 105                         device_fd = tunemu_open(dynamic_name);
 106                 }
 107                         break;
 108 #endif
 109                 default:
 110                         device_fd = open(device, O_RDWR | O_NONBLOCK);
 111         }
 112
 113         if(device_fd < 0) {
 114                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
 115                 return false;
 116         }
 117
 118 #ifdef FD_CLOEXEC
 119         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 120 #endif
 121
 122         switch(device_type) {
 123                 default:
 124                         device_type = DEVICE_TYPE_TUN;
 125                 case DEVICE_TYPE_TUN:
 126 #ifdef TUNSIFHEAD
 127                 {
 128                         const int zero = 0;
 129                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 130                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 131                                 return false;
 132                         }
 133                 }
 134 #endif
 135 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 136                 {
 137                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 138                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 139                 }
 140 #endif
 141
 142                         device_info = "Generic BSD tun device";
 143                         break;
 144                 case DEVICE_TYPE_TUNIFHEAD:
 145 #ifdef TUNSIFHEAD
 146                 {
 147                         const int one = 1;
 148                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 149                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 150                                 return false;
 151                         }
 152                 }
 153 #endif
 154 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 155                 {
 156                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 157                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 158                 }
 159 #endif
 160
 161                         device_info = "Generic BSD tun device";
 162                         break;
 163                 case DEVICE_TYPE_TAP:
 164                         if(routing_mode == RMODE_ROUTER)
 165                                 overwrite_mac = true;
 166                         device_info = "Generic BSD tap device";
 167 #ifdef TAPGIFNAME
 168                         {
 169                                 struct ifreq ifr;
 170                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 171                                         if(iface)
 172                                                 free(iface);
 173                                         iface = xstrdup(ifr.ifr_name);
 174                                 }
 175                         }
 176
 177 #endif
 178                         break;
 179 #ifdef HAVE_TUNEMU
 180                 case DEVICE_TYPE_TUNEMU:
 181                         device_info = "BSD tunemu device";
 182                         break;
 183 #endif
 184         }
 185
 186         logger(LOG_INFO, "%s is a %s", device, device_info);
 187
 188         return true;
 189 }
 190
 191 static void close_device(void) {
 192         switch(device_type) {
 193 #ifdef HAVE_TUNEMU
 194                 case DEVICE_TYPE_TUNEMU:
 195                         tunemu_close(device_fd);
 196                         break;
 197 #endif
 198                 default:
 199                         close(device_fd);
 200         }
 201
 202         free(device);
 203         free(iface);
 204 }
 205
 206 static bool read_packet(vpn_packet_t *packet) {
 207         int lenin;
 208
 209         switch(device_type) {
 210                 case DEVICE_TYPE_TUN:
 211 #ifdef HAVE_TUNEMU
 212                 case DEVICE_TYPE_TUNEMU:
 213                         if(device_type == DEVICE_TYPE_TUNEMU)
 214                                 lenin = tunemu_read(device_fd, packet->data + 14, MTU - 14);
 215                         else
 216 #endif
 217                                 lenin = read(device_fd, packet->data + 14, MTU - 14);
 218
 219                         if(lenin <= 0) {
 220                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 221                                            device, strerror(errno));
 222                                 return false;
 223                         }
 224
 225                         switch(packet->data[14] >> 4) {
 226                                 case 4:
 227                                         packet->data[12] = 0x08;
 228                                         packet->data[13] = 0x00;
 229                                         break;
 230                                 case 6:
 231                                         packet->data[12] = 0x86;
 232                                         packet->data[13] = 0xDD;
 233                                         break;
 234                                 default:
 235                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 236                                                            "Unknown IP version %d while reading packet from %s %s",
 237                                                            packet->data[14] >> 4, device_info, device);
 238                                         return false;
 239                         }
 240
 241                         packet->len = lenin + 14;
 242                         break;
 243
 244                 case DEVICE_TYPE_TUNIFHEAD: {
 245                         u_int32_t type;
 246                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, MTU - 14}};
 247
 248                         if((lenin = readv(device_fd, vector, 2)) <= 0) {
 249                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 250                                            device, strerror(errno));
 251                                 return false;
 252                         }
 253
 254                         switch (ntohl(type)) {
 255                                 case AF_INET:
 256                                         packet->data[12] = 0x08;
 257                                         packet->data[13] = 0x00;
 258                                         break;
 259
 260                                 case AF_INET6:
 261                                         packet->data[12] = 0x86;
 262                                         packet->data[13] = 0xDD;
 263                                         break;
 264
 265                                 default:
 266                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 267                                                            "Unknown address family %x while reading packet from %s %s",
 268                                                            ntohl(type), device_info, device);
 269                                         return false;
 270                         }
 271
 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 HAVE_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 };