src/bsd/device.c

   1 /*
   2     device.c -- Interaction BSD tun/tap device
   3     Copyright (C) 2001-2005 Ivo Timmermans,
   4                   2001-2011 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         switch(device_type) {
 110                 default:
 111                         device_type = DEVICE_TYPE_TUN;
 112                 case DEVICE_TYPE_TUN:
 113 #ifdef TUNSIFHEAD
 114                 {
 115                         const int zero = 0;
 116                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 117                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 118                                 return false;
 119                         }
 120                 }
 121 #endif
 122 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 123                 {
 124                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 125                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 126                 }
 127 #endif
 128
 129                         device_info = "Generic BSD tun device";
 130                         break;
 131                 case DEVICE_TYPE_TUNIFHEAD:
 132 #ifdef TUNSIFHEAD
 133                 {
 134                         const int one = 1;
 135                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 136                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 137                                 return false;
 138                         }
 139                 }
 140 #endif
 141 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 142                 {
 143                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 144                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 145                 }
 146 #endif
 147
 148                         device_info = "Generic BSD tun device";
 149                         break;
 150                 case DEVICE_TYPE_TAP:
 151                         if(routing_mode == RMODE_ROUTER)
 152                                 overwrite_mac = true;
 153                         device_info = "Generic BSD tap device";
 154 #ifdef TAPGIFNAME
 155                         {
 156                                 struct ifreq ifr;
 157                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 158                                         if(iface)
 159                                                 free(iface);
 160                                         iface = xstrdup(ifr.ifr_name);
 161                                 }
 162                         }
 163
 164 #endif
 165                         break;
 166 #ifdef HAVE_TUNEMU
 167                 case DEVICE_TYPE_TUNEMU:
 168                         device_info = "BSD tunemu device";
 169                         break;
 170 #endif
 171         }
 172
 173         logger(LOG_INFO, "%s is a %s", device, device_info);
 174
 175         return true;
 176 }
 177
 178 static void close_device(void) {
 179         switch(device_type) {
 180 #ifdef HAVE_TUNEMU
 181                 case DEVICE_TYPE_TUNEMU:
 182                         tunemu_close(device_fd);
 183                         break;
 184 #endif
 185                 default:
 186                         close(device_fd);
 187         }
 188
 189         free(device);
 190         free(iface);
 191 }
 192
 193 static bool read_packet(vpn_packet_t *packet) {
 194         int lenin;
 195
 196         switch(device_type) {
 197                 case DEVICE_TYPE_TUN:
 198 #ifdef HAVE_TUNEMU
 199                 case DEVICE_TYPE_TUNEMU:
 200                         if(device_type == DEVICE_TYPE_TUNEMU)
 201                                 lenin = tunemu_read(device_fd, packet->data + 14, MTU - 14);
 202                         else
 203 #endif
 204                                 lenin = read(device_fd, packet->data + 14, MTU - 14);
 205
 206                         if(lenin <= 0) {
 207                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 208                                            device, strerror(errno));
 209                                 return false;
 210                         }
 211
 212                         switch(packet->data[14] >> 4) {
 213                                 case 4:
 214                                         packet->data[12] = 0x08;
 215                                         packet->data[13] = 0x00;
 216                                         break;
 217                                 case 6:
 218                                         packet->data[12] = 0x86;
 219                                         packet->data[13] = 0xDD;
 220                                         break;
 221                                 default:
 222                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 223                                                            "Unknown IP version %d while reading packet from %s %s",
 224                                                            packet->data[14] >> 4, device_info, device);
 225                                         return false;
 226                         }
 227
 228                         packet->len = lenin + 14;
 229                         break;
 230
 231                 case DEVICE_TYPE_TUNIFHEAD: {
 232                         u_int32_t type;
 233                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, MTU - 14}};
 234
 235                         if((lenin = readv(device_fd, vector, 2)) <= 0) {
 236                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 237                                            device, strerror(errno));
 238                                 return false;
 239                         }
 240
 241                         switch (ntohl(type)) {
 242                                 case AF_INET:
 243                                         packet->data[12] = 0x08;
 244                                         packet->data[13] = 0x00;
 245                                         break;
 246
 247                                 case AF_INET6:
 248                                         packet->data[12] = 0x86;
 249                                         packet->data[13] = 0xDD;
 250                                         break;
 251
 252                                 default:
 253                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 254                                                            "Unknown address family %x while reading packet from %s %s",
 255                                                            ntohl(type), device_info, device);
 256                                         return false;
 257                         }
 258
 259                         packet->len = lenin + 10;
 260                         break;
 261                 }
 262
 263                 case DEVICE_TYPE_TAP:
 264                         if((lenin = read(device_fd, packet->data, MTU)) <= 0) {
 265                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 266                                            device, strerror(errno));
 267                                 return false;
 268                         }
 269
 270                         packet->len = lenin;
 271                         break;
 272
 273                 default:
 274                         return false;
 275         }
 276
 277         device_total_in += packet->len;
 278
 279         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s",
 280                            packet->len, device_info);
 281
 282         return true;
 283 }
 284
 285 static bool write_packet(vpn_packet_t *packet) {
 286         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 287                            packet->len, device_info);
 288
 289         switch(device_type) {
 290                 case DEVICE_TYPE_TUN:
 291                         if(write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 292                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 293                                            device, strerror(errno));
 294                                 return false;
 295                         }
 296                         break;
 297
 298                 case DEVICE_TYPE_TUNIFHEAD: {
 299                         u_int32_t type;
 300                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, packet->len - 14}};
 301                         int af;
 302
 303                         af = (packet->data[12] << 8) + packet->data[13];
 304
 305                         switch (af) {
 306                                 case 0x0800:
 307                                         type = htonl(AF_INET);
 308                                         break;
 309                                 case 0x86DD:
 310                                         type = htonl(AF_INET6);
 311                                         break;
 312                                 default:
 313                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 314                                                            "Unknown address family %x while writing packet to %s %s",
 315                                                            af, device_info, device);
 316                                         return false;
 317                         }
 318
 319                         if(writev(device_fd, vector, 2) < 0) {
 320                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 321                                            strerror(errno));
 322                                 return false;
 323                         }
 324                         break;
 325                 }
 326
 327                 case DEVICE_TYPE_TAP:
 328                         if(write(device_fd, packet->data, packet->len) < 0) {
 329                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 330                                            device, strerror(errno));
 331                                 return false;
 332                         }
 333                         break;
 334
 335 #ifdef HAVE_TUNEMU
 336                 case DEVICE_TYPE_TUNEMU:
 337                         if(tunemu_write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 338                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 339                                            device, strerror(errno));
 340                                 return false;
 341                         }
 342                         break;
 343 #endif
 344
 345                 default:
 346                         return false;
 347         }
 348
 349         device_total_out += packet->len;
 350
 351         return true;
 352 }
 353
 354 static void dump_device_stats(void) {
 355         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 356         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 357         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 358 }
 359
 360 const devops_t os_devops = {
 361         .setup = setup_device,
 362         .close = close_device,
 363         .read = read_packet,
 364         .write = write_packet,
 365         .dump_stats = dump_device_stats,
 366 };