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