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 #ifdef HAVE_NET_IF_UTUN_H
  37 #include <sys/sys_domain.h>
  38 #include <sys/kern_control.h>
  39 #include <net/if_utun.h>
  40 #endif
  41
  42 #define DEFAULT_TUN_DEVICE "/dev/tun0"
  43 #define DEFAULT_TAP_DEVICE "/dev/tap0"
  44
  45 typedef enum device_type {
  46         DEVICE_TYPE_TUN,
  47         DEVICE_TYPE_TUNIFHEAD,
  48         DEVICE_TYPE_TAP,
  49 #ifdef ENABLE_TUNEMU
  50         DEVICE_TYPE_TUNEMU,
  51 #endif
  52 #ifdef HAVE_NET_IF_UTUN_H
  53         DEVICE_TYPE_UTUN,
  54 #endif
  55 } device_type_t;
  56
  57 int device_fd = -1;
  58 char *device = NULL;
  59 char *iface = NULL;
  60 static char *device_info = NULL;
  61 static uint64_t device_total_in = 0;
  62 static uint64_t device_total_out = 0;
  63 #if defined(ENABLE_TUNEMU)
  64 static device_type_t device_type = DEVICE_TYPE_TUNEMU;
  65 #elif defined(HAVE_OPENBSD) || defined(HAVE_FREEBSD) || defined(HAVE_DRAGONFLY)
  66 static device_type_t device_type = DEVICE_TYPE_TUNIFHEAD;
  67 #else
  68 static device_type_t device_type = DEVICE_TYPE_TUN;
  69 #endif
  70
  71 #ifdef HAVE_NET_IF_UTUN_H
  72 static bool setup_utun(void) {
  73         device_fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
  74         if(device_fd == -1) {
  75                 logger(LOG_ERR, "Could not open PF_SYSTEM socket: %s\n", strerror(errno));
  76                 return false;
  77         }
  78
  79         struct ctl_info info = {};
  80         strlcpy(info.ctl_name, UTUN_CONTROL_NAME, sizeof info.ctl_name);
  81
  82         if(ioctl(device_fd, CTLIOCGINFO, &info) == -1) {
  83                 logger(LOG_ERR, "ioctl(CTLIOCGINFO) failed: %s", strerror(errno));
  84                 return false;
  85         }
  86
  87         int unit = -1;
  88         char *p = strstr(device, "utun"), *e = NULL;
  89         if(p) {
  90                 unit = strtol(p + 4, &e, 10);
  91                 if(!e)
  92                         unit = -1;
  93         }
  94
  95         struct sockaddr_ctl sc = {
  96                 .sc_id = info.ctl_id,
  97                 .sc_len = sizeof sc,
  98                 .sc_family = AF_SYSTEM,
  99                 .ss_sysaddr = AF_SYS_CONTROL,
 100                 .sc_unit = unit + 1,
 101         };
 102
 103         if(connect(device_fd, (struct sockaddr *)&sc, sizeof(sc)) == -1) {
 104                 logger(LOG_ERR, "Could not connect utun socket: %s\n", strerror(errno));
 105                 return false;
 106         }
 107
 108         char name[64] = "";
 109         socklen_t len = sizeof name;
 110         if(getsockopt(device_fd, SYSPROTO_CONTROL, UTUN_OPT_IFNAME, name, &len)) {
 111                 iface = xstrdup(device);
 112         } else {
 113                 iface = xstrdup(name);
 114         }
 115
 116         device_info = "OS X utun device";
 117
 118         logger(LOG_INFO, "%s is a %s", device, device_info);
 119
 120         return true;
 121 }
 122 #endif
 123
 124 static bool setup_device(void) {
 125         // Find out which device file to open
 126
 127         if(!get_config_string(lookup_config(config_tree, "Device"), &device)) {
 128                 if(routing_mode == RMODE_ROUTER)
 129                         device = xstrdup(DEFAULT_TUN_DEVICE);
 130                 else
 131                         device = xstrdup(DEFAULT_TAP_DEVICE);
 132         }
 133
 134         // Find out if it's supposed to be a tun or a tap device
 135
 136         char *type;
 137
 138         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
 139                 if(!strcasecmp(type, "tun"))
 140                         /* use default */;
 141 #ifdef ENABLE_TUNEMU
 142                 else if(!strcasecmp(type, "tunemu"))
 143                         device_type = DEVICE_TYPE_TUNEMU;
 144 #endif
 145 #ifdef HAVE_NET_IF_UTUN_H
 146                 else if(!strcasecmp(type, "utun"))
 147                         device_type = DEVICE_TYPE_UTUN;
 148 #endif
 149                 else if(!strcasecmp(type, "tunnohead"))
 150                         device_type = DEVICE_TYPE_TUN;
 151                 else if(!strcasecmp(type, "tunifhead"))
 152                         device_type = DEVICE_TYPE_TUNIFHEAD;
 153                 else if(!strcasecmp(type, "tap"))
 154                         device_type = DEVICE_TYPE_TAP;
 155                 else {
 156                         logger(LOG_ERR, "Unknown device type %s!", type);
 157                         return false;
 158                 }
 159         } else {
 160 #ifdef HAVE_NET_IF_UTUN_H
 161                 if(strncmp(device, "utun", 4) == 0 || strncmp(device, "/dev/utun", 9) == 0)
 162                         device_type = DEVICE_TYPE_UTUN;
 163                 else
 164 #endif
 165                 if(strstr(device, "tap") || routing_mode != RMODE_ROUTER)
 166                         device_type = DEVICE_TYPE_TAP;
 167         }
 168
 169         if(routing_mode == RMODE_SWITCH && device_type != DEVICE_TYPE_TAP) {
 170                 logger(LOG_ERR, "Only tap devices support switch mode!");
 171                 return false;
 172         }
 173
 174         // Open the device
 175
 176         switch(device_type) {
 177 #ifdef ENABLE_TUNEMU
 178                 case DEVICE_TYPE_TUNEMU: {
 179                         char dynamic_name[256] = "";
 180                         device_fd = tunemu_open(dynamic_name);
 181                 }
 182                         break;
 183 #endif
 184 #ifdef HAVE_NET_IF_UTUN_H
 185                 case DEVICE_TYPE_UTUN:
 186                         return setup_utun();
 187 #endif
 188                 default:
 189                         device_fd = open(device, O_RDWR | O_NONBLOCK);
 190         }
 191
 192         if(device_fd < 0) {
 193                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
 194                 return false;
 195         }
 196
 197 #ifdef FD_CLOEXEC
 198         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 199 #endif
 200
 201         // Guess what the corresponding interface is called
 202
 203         char *realname;
 204
 205 #if defined(HAVE_FDEVNAME)
 206         realname = fdevname(device_fd) ? : device;
 207 #elif defined(HAVE_DEVNAME)
 208         struct stat buf;
 209         if(!fstat(device_fd, &buf))
 210                 realname = devname(buf.st_rdev, S_IFCHR) ? : device;
 211 #else
 212         realname = device;
 213 #endif
 214
 215         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
 216                 iface = xstrdup(strrchr(realname, '/') ? strrchr(realname, '/') + 1 : realname);
 217         else if(strcmp(iface, strrchr(realname, '/') ? strrchr(realname, '/') + 1 : realname))
 218                 logger(LOG_WARNING, "Warning: Interface does not match Device. $INTERFACE might be set incorrectly.");
 219
 220         // Configure the device as best as we can
 221
 222         switch(device_type) {
 223                 default:
 224                         device_type = DEVICE_TYPE_TUN;
 225                 case DEVICE_TYPE_TUN:
 226 #ifdef TUNSIFHEAD
 227                 {
 228                         const int zero = 0;
 229                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 230                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 231                                 return false;
 232                         }
 233                 }
 234 #endif
 235 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 236                 {
 237                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 238                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 239                 }
 240 #endif
 241
 242                         device_info = "Generic BSD tun device";
 243                         break;
 244                 case DEVICE_TYPE_TUNIFHEAD:
 245 #ifdef TUNSIFHEAD
 246                 {
 247                         const int one = 1;
 248                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 249                                 logger(LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 250                                 return false;
 251                         }
 252                 }
 253 #endif
 254 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 255                 {
 256                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 257                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 258                 }
 259 #endif
 260
 261                         device_info = "Generic BSD tun device";
 262                         break;
 263                 case DEVICE_TYPE_TAP:
 264                         if(routing_mode == RMODE_ROUTER)
 265                                 overwrite_mac = true;
 266                         device_info = "Generic BSD tap device";
 267 #ifdef TAPGIFNAME
 268                         {
 269                                 struct ifreq ifr;
 270                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 271                                         if(iface)
 272                                                 free(iface);
 273                                         iface = xstrdup(ifr.ifr_name);
 274                                 }
 275                         }
 276
 277 #endif
 278                         break;
 279 #ifdef ENABLE_TUNEMU
 280                 case DEVICE_TYPE_TUNEMU:
 281                         device_info = "BSD tunemu device";
 282                         break;
 283 #endif
 284         }
 285
 286 #ifdef SIOCGIFADDR
 287         if(overwrite_mac)
 288                 ioctl(device_fd, SIOCGIFADDR, mymac.x);
 289 #endif
 290
 291         logger(LOG_INFO, "%s is a %s", device, device_info);
 292
 293         return true;
 294 }
 295
 296 static void close_device(void) {
 297         switch(device_type) {
 298 #ifdef ENABLE_TUNEMU
 299                 case DEVICE_TYPE_TUNEMU:
 300                         tunemu_close(device_fd);
 301                         break;
 302 #endif
 303                 default:
 304                         close(device_fd);
 305         }
 306
 307         free(device);
 308         free(iface);
 309 }
 310
 311 static bool read_packet(vpn_packet_t *packet) {
 312         int lenin;
 313
 314         switch(device_type) {
 315                 case DEVICE_TYPE_TUN:
 316 #ifdef ENABLE_TUNEMU
 317                 case DEVICE_TYPE_TUNEMU:
 318                         if(device_type == DEVICE_TYPE_TUNEMU)
 319                                 lenin = tunemu_read(device_fd, packet->data + 14, MTU - 14);
 320                         else
 321 #endif
 322                                 lenin = read(device_fd, packet->data + 14, MTU - 14);
 323
 324                         if(lenin <= 0) {
 325                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 326                                            device, strerror(errno));
 327                                 return false;
 328                         }
 329
 330                         switch(packet->data[14] >> 4) {
 331                                 case 4:
 332                                         packet->data[12] = 0x08;
 333                                         packet->data[13] = 0x00;
 334                                         break;
 335                                 case 6:
 336                                         packet->data[12] = 0x86;
 337                                         packet->data[13] = 0xDD;
 338                                         break;
 339                                 default:
 340                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 341                                                            "Unknown IP version %d while reading packet from %s %s",
 342                                                            packet->data[14] >> 4, device_info, device);
 343                                         return false;
 344                         }
 345
 346                         memset(packet->data, 0, 12);
 347                         packet->len = lenin + 14;
 348                         break;
 349
 350                 case DEVICE_TYPE_UTUN:
 351                 case DEVICE_TYPE_TUNIFHEAD: {
 352                         if((lenin = read(device_fd, packet->data + 10, MTU - 10)) <= 0) {
 353                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 354                                            device, strerror(errno));
 355                                 return false;
 356                         }
 357
 358                         switch(packet->data[14] >> 4) {
 359                                 case 4:
 360                                         packet->data[12] = 0x08;
 361                                         packet->data[13] = 0x00;
 362                                         break;
 363                                 case 6:
 364                                         packet->data[12] = 0x86;
 365                                         packet->data[13] = 0xDD;
 366                                         break;
 367                                 default:
 368                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 369                                                            "Unknown IP version %d while reading packet from %s %s",
 370                                                            packet->data[14] >> 4, device_info, device);
 371                                         return false;
 372                         }
 373
 374                         memset(packet->data, 0, 12);
 375                         packet->len = lenin + 10;
 376                         break;
 377                 }
 378
 379                 case DEVICE_TYPE_TAP:
 380                         if((lenin = read(device_fd, packet->data, MTU)) <= 0) {
 381                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 382                                            device, strerror(errno));
 383                                 return false;
 384                         }
 385
 386                         packet->len = lenin;
 387                         break;
 388
 389                 default:
 390                         return false;
 391         }
 392
 393         device_total_in += packet->len;
 394
 395         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s",
 396                            packet->len, device_info);
 397
 398         return true;
 399 }
 400
 401 static bool write_packet(vpn_packet_t *packet) {
 402         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 403                            packet->len, device_info);
 404
 405         switch(device_type) {
 406                 case DEVICE_TYPE_TUN:
 407                         if(write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 408                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 409                                            device, strerror(errno));
 410                                 return false;
 411                         }
 412                         break;
 413
 414                 case DEVICE_TYPE_UTUN:
 415                 case DEVICE_TYPE_TUNIFHEAD: {
 416                         int af = (packet->data[12] << 8) + packet->data[13];
 417                         uint32_t type;
 418
 419                         switch (af) {
 420                                 case 0x0800:
 421                                         type = htonl(AF_INET);
 422                                         break;
 423                                 case 0x86DD:
 424                                         type = htonl(AF_INET6);
 425                                         break;
 426                                 default:
 427                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 428                                                            "Unknown address family %x while writing packet to %s %s",
 429                                                            af, device_info, device);
 430                                         return false;
 431                         }
 432
 433                         memcpy(packet->data + 10, &type, sizeof type);
 434
 435                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 436                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 437                                            strerror(errno));
 438                                 return false;
 439                         }
 440                         break;
 441                 }
 442
 443                 case DEVICE_TYPE_TAP:
 444                         if(write(device_fd, packet->data, packet->len) < 0) {
 445                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 446                                            device, strerror(errno));
 447                                 return false;
 448                         }
 449                         break;
 450
 451 #ifdef ENABLE_TUNEMU
 452                 case DEVICE_TYPE_TUNEMU:
 453                         if(tunemu_write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 454                                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info,
 455                                            device, strerror(errno));
 456                                 return false;
 457                         }
 458                         break;
 459 #endif
 460
 461                 default:
 462                         return false;
 463         }
 464
 465         device_total_out += packet->len;
 466
 467         return true;
 468 }
 469
 470 static void dump_device_stats(void) {
 471         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 472         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 473         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 474 }
 475
 476 const devops_t os_devops = {
 477         .setup = setup_device,
 478         .close = close_device,
 479         .read = read_packet,
 480         .write = write_packet,
 481         .dump_stats = dump_device_stats,
 482 };