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                   2001-2022 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 "../route.h"
  28 #include "../xalloc.h"
  29
  30 #ifdef ENABLE_TUNEMU
  31 #include "tunemu.h"
  32 #endif
  33
  34 #ifdef HAVE_NET_IF_UTUN_H
  35 #include <sys/sys_domain.h>
  36 #include <sys/kern_control.h>
  37 #include <net/if_utun.h>
  38 #endif
  39
  40 #if defined(HAVE_FREEBSD) || defined(HAVE_DRAGONFLY)
  41 #define DEFAULT_TUN_DEVICE "/dev/tun"  // Use the autoclone device
  42 #define DEFAULT_TAP_DEVICE "/dev/tap"
  43 #else
  44 #define DEFAULT_TUN_DEVICE "/dev/tun0"
  45 #define DEFAULT_TAP_DEVICE "/dev/tap0"
  46 #endif
  47
  48 typedef enum device_type {
  49         DEVICE_TYPE_TUN,
  50         DEVICE_TYPE_TUNIFHEAD,
  51         DEVICE_TYPE_TAP,
  52 #ifdef ENABLE_TUNEMU
  53         DEVICE_TYPE_TUNEMU,
  54 #endif
  55         DEVICE_TYPE_UTUN,
  56 } device_type_t;
  57
  58 int device_fd = -1;
  59 char *device = NULL;
  60 char *iface = NULL;
  61 static const char *device_info = "OS X utun device";
  62 #if defined(ENABLE_TUNEMU)
  63 static device_type_t device_type = DEVICE_TYPE_TUNEMU;
  64 #elif defined(HAVE_OPENBSD) || defined(HAVE_FREEBSD) || defined(HAVE_DRAGONFLY)
  65 static device_type_t device_type = DEVICE_TYPE_TUNIFHEAD;
  66 #else
  67 static device_type_t device_type = DEVICE_TYPE_TUN;
  68 #endif
  69
  70 #ifdef HAVE_NET_IF_UTUN_H
  71 static bool setup_utun(void) {
  72         device_fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
  73
  74         if(device_fd == -1) {
  75                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open PF_SYSTEM socket: %s\n", strerror(errno));
  76                 return false;
  77         }
  78
  79         struct ctl_info info;
  80
  81         memset(&info, 0, sizeof(info));
  82
  83         strlcpy(info.ctl_name, UTUN_CONTROL_NAME, sizeof(info.ctl_name));
  84
  85         if(ioctl(device_fd, CTLIOCGINFO, &info) == -1) {
  86                 logger(DEBUG_ALWAYS, LOG_ERR, "ioctl(CTLIOCGINFO) failed: %s", strerror(errno));
  87                 return false;
  88         }
  89
  90         long unit = -1;
  91         char *p = strstr(device, "utun"), *e = NULL;
  92
  93         if(p) {
  94                 unit = strtol(p + 4, &e, 10);
  95
  96                 if(!e) {
  97                         unit = -1;
  98                 }
  99         }
 100
 101         struct sockaddr_ctl sc = {
 102                 .sc_id = info.ctl_id,
 103                 .sc_len = sizeof(sc),
 104                 .sc_family = AF_SYSTEM,
 105                 .ss_sysaddr = AF_SYS_CONTROL,
 106                 .sc_unit = unit + 1,
 107         };
 108
 109         if(connect(device_fd, (struct sockaddr *)&sc, sizeof(sc)) == -1) {
 110                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not connect utun socket: %s\n", strerror(errno));
 111                 return false;
 112         }
 113
 114         char name[64] = "";
 115         socklen_t len = sizeof(name);
 116
 117         if(getsockopt(device_fd, SYSPROTO_CONTROL, UTUN_OPT_IFNAME, name, &len)) {
 118                 iface = xstrdup(device);
 119         } else {
 120                 iface = xstrdup(name);
 121         }
 122
 123         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 124
 125         return true;
 126 }
 127 #endif
 128
 129 static bool setup_device(void) {
 130         get_config_string(lookup_config(&config_tree, "Device"), &device);
 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
 140 #ifdef ENABLE_TUNEMU
 141                 else if(!strcasecmp(type, "tunemu")) {
 142                         device_type = DEVICE_TYPE_TUNEMU;
 143                 }
 144
 145 #endif
 146 #ifdef HAVE_NET_IF_UTUN_H
 147                 else if(!strcasecmp(type, "utun")) {
 148                         device_type = DEVICE_TYPE_UTUN;
 149                 }
 150
 151 #endif
 152                 else if(!strcasecmp(type, "tunnohead")) {
 153                         device_type = DEVICE_TYPE_TUN;
 154                 } else if(!strcasecmp(type, "tunifhead")) {
 155                         device_type = DEVICE_TYPE_TUNIFHEAD;
 156                 } else if(!strcasecmp(type, "tap")) {
 157                         device_type = DEVICE_TYPE_TAP;
 158                 } else {
 159                         logger(DEBUG_ALWAYS, LOG_ERR, "Unknown device type %s!", type);
 160                         return false;
 161                 }
 162         } else {
 163 #ifdef HAVE_NET_IF_UTUN_H
 164
 165                 if(device && (strncmp(device, "utun", 4) == 0 || strncmp(device, "/dev/utun", 9) == 0)) {
 166                         device_type = DEVICE_TYPE_UTUN;
 167                 } else
 168 #endif
 169                         if((device && strstr(device, "tap")) || routing_mode != RMODE_ROUTER) {
 170                                 device_type = DEVICE_TYPE_TAP;
 171                         }
 172         }
 173
 174         if(routing_mode == RMODE_SWITCH && device_type != DEVICE_TYPE_TAP) {
 175                 logger(DEBUG_ALWAYS, LOG_ERR, "Only tap devices support switch mode!");
 176                 return false;
 177         }
 178
 179         // Find out which device file to open
 180
 181         if(!device) {
 182                 if(device_type == DEVICE_TYPE_TAP) {
 183                         device = xstrdup(DEFAULT_TAP_DEVICE);
 184                 } else {
 185                         device = xstrdup(DEFAULT_TUN_DEVICE);
 186                 }
 187         }
 188
 189         // Open the device
 190
 191         switch(device_type) {
 192 #ifdef ENABLE_TUNEMU
 193
 194         case DEVICE_TYPE_TUNEMU: {
 195                 char dynamic_name[256] = "";
 196                 device_fd = tunemu_open(dynamic_name);
 197         }
 198         break;
 199 #endif
 200 #ifdef HAVE_NET_IF_UTUN_H
 201
 202         case DEVICE_TYPE_UTUN:
 203                 return setup_utun();
 204 #endif
 205
 206         default:
 207                 device_fd = open(device, O_RDWR | O_NONBLOCK);
 208         }
 209
 210         if(device_fd < 0) {
 211                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open %s: %s", device, strerror(errno));
 212                 return false;
 213         }
 214
 215 #ifdef FD_CLOEXEC
 216         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 217 #endif
 218
 219         // Guess what the corresponding interface is called
 220
 221         char *realname = NULL;
 222
 223 #if defined(HAVE_FDEVNAME)
 224         realname = fdevname(device_fd);
 225 #elif defined(HAVE_DEVNAME)
 226         struct stat buf;
 227
 228         if(!fstat(device_fd, &buf)) {
 229                 realname = devname(buf.st_rdev, S_IFCHR);
 230         }
 231
 232 #endif
 233
 234         if(!realname) {
 235                 realname = device;
 236         }
 237
 238         if(!get_config_string(lookup_config(&config_tree, "Interface"), &iface)) {
 239                 iface = xstrdup(strrchr(realname, '/') ? strrchr(realname, '/') + 1 : realname);
 240         } else if(strcmp(iface, strrchr(realname, '/') ? strrchr(realname, '/') + 1 : realname)) {
 241                 logger(DEBUG_ALWAYS, LOG_WARNING, "Warning: Interface does not match Device. $INTERFACE might be set incorrectly.");
 242         }
 243
 244         // Configure the device as best as we can
 245
 246         switch(device_type) {
 247         default:
 248                 device_type = DEVICE_TYPE_TUN;
 249
 250         case DEVICE_TYPE_TUN:
 251 #ifdef TUNSIFHEAD
 252                 {
 253                         const int zero = 0;
 254
 255                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof(zero)) == -1) {
 256                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 257                                 return false;
 258                         }
 259                 }
 260
 261 #endif
 262 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 263                 {
 264                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 265                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof(mode));
 266                 }
 267 #endif
 268
 269                 device_info = "Generic BSD tun device";
 270                 break;
 271
 272         case DEVICE_TYPE_TUNIFHEAD:
 273 #ifdef TUNSIFHEAD
 274                 {
 275                         const int one = 1;
 276
 277                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof(one)) == -1) {
 278                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 279                                 return false;
 280                         }
 281                 }
 282
 283 #endif
 284 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 285                 {
 286                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 287                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof(mode));
 288                 }
 289 #endif
 290
 291                 device_info = "Generic BSD tun device";
 292                 break;
 293
 294         case DEVICE_TYPE_TAP:
 295                 if(routing_mode == RMODE_ROUTER) {
 296                         overwrite_mac = true;
 297                 }
 298
 299                 device_info = "Generic BSD tap device";
 300 #ifdef TAPGIFNAME
 301                 {
 302                         struct ifreq ifr;
 303
 304                         if(ioctl(device_fd, TAPGIFNAME, (void *)&ifr) == 0) {
 305                                 free(iface);
 306                                 iface = xstrdup(ifr.ifr_name);
 307                         }
 308                 }
 309
 310 #endif
 311                 break;
 312 #ifdef ENABLE_TUNEMU
 313
 314         case DEVICE_TYPE_TUNEMU:
 315                 device_info = "BSD tunemu device";
 316                 break;
 317 #endif
 318         }
 319
 320 #ifdef SIOCGIFADDR
 321
 322         if(overwrite_mac) {
 323                 ioctl(device_fd, SIOCGIFADDR, mymac.x);
 324         }
 325
 326 #endif
 327
 328         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 329
 330         return true;
 331 }
 332
 333 static void close_device(void) {
 334         switch(device_type) {
 335 #ifdef ENABLE_TUNEMU
 336
 337         case DEVICE_TYPE_TUNEMU:
 338                 tunemu_close(device_fd);
 339                 break;
 340 #endif
 341
 342         default:
 343                 close(device_fd);
 344         }
 345
 346         device_fd = -1;
 347
 348         free(device);
 349         device = NULL;
 350         free(iface);
 351         iface = NULL;
 352         device_info = NULL;
 353 }
 354
 355 static bool read_packet(vpn_packet_t *packet) {
 356         ssize_t inlen;
 357
 358         switch(device_type) {
 359         case DEVICE_TYPE_TUN:
 360 #ifdef ENABLE_TUNEMU
 361         case DEVICE_TYPE_TUNEMU:
 362                 if(device_type == DEVICE_TYPE_TUNEMU) {
 363                         inlen = tunemu_read(device_fd, DATA(packet) + 14, MTU - 14);
 364                 } else
 365 #endif
 366                         inlen = read(device_fd, DATA(packet) + 14, MTU - 14);
 367
 368                 if(inlen <= 0) {
 369                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 370                                device, strerror(errno));
 371                         return false;
 372                 }
 373
 374                 switch(DATA(packet)[14] >> 4) {
 375                 case 4:
 376                         DATA(packet)[12] = 0x08;
 377                         DATA(packet)[13] = 0x00;
 378                         break;
 379
 380                 case 6:
 381                         DATA(packet)[12] = 0x86;
 382                         DATA(packet)[13] = 0xDD;
 383                         break;
 384
 385                 default:
 386                         logger(DEBUG_TRAFFIC, LOG_ERR,
 387                                "Unknown IP version %d while reading packet from %s %s",
 388                                DATA(packet)[14] >> 4, device_info, device);
 389                         return false;
 390                 }
 391
 392                 memset(DATA(packet), 0, 12);
 393                 packet->len = inlen + 14;
 394                 break;
 395
 396         case DEVICE_TYPE_UTUN:
 397         case DEVICE_TYPE_TUNIFHEAD: {
 398                 if((inlen = read(device_fd, DATA(packet) + 10, MTU - 10)) <= 0) {
 399                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 400                                device, strerror(errno));
 401                         return false;
 402                 }
 403
 404                 switch(DATA(packet)[14] >> 4) {
 405                 case 4:
 406                         DATA(packet)[12] = 0x08;
 407                         DATA(packet)[13] = 0x00;
 408                         break;
 409
 410                 case 6:
 411                         DATA(packet)[12] = 0x86;
 412                         DATA(packet)[13] = 0xDD;
 413                         break;
 414
 415                 default:
 416                         logger(DEBUG_TRAFFIC, LOG_ERR,
 417                                "Unknown IP version %d while reading packet from %s %s",
 418                                DATA(packet)[14] >> 4, device_info, device);
 419                         return false;
 420                 }
 421
 422                 memset(DATA(packet), 0, 12);
 423                 packet->len = inlen + 10;
 424                 break;
 425         }
 426
 427         case DEVICE_TYPE_TAP:
 428                 if((inlen = read(device_fd, DATA(packet), MTU)) <= 0) {
 429                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 430                                device, strerror(errno));
 431                         return false;
 432                 }
 433
 434                 packet->len = inlen;
 435                 break;
 436
 437         default:
 438                 return false;
 439         }
 440
 441         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s",
 442                packet->len, device_info);
 443
 444         return true;
 445 }
 446
 447 static bool write_packet(vpn_packet_t *packet) {
 448         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 449                packet->len, device_info);
 450
 451         switch(device_type) {
 452         case DEVICE_TYPE_TUN:
 453                 if(write(device_fd, DATA(packet) + 14, packet->len - 14) < 0) {
 454                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 455                                device, strerror(errno));
 456                         return false;
 457                 }
 458
 459                 break;
 460
 461         case DEVICE_TYPE_UTUN:
 462         case DEVICE_TYPE_TUNIFHEAD: {
 463                 int af = (DATA(packet)[12] << 8) + DATA(packet)[13];
 464                 uint32_t type;
 465
 466                 switch(af) {
 467                 case 0x0800:
 468                         type = htonl(AF_INET);
 469                         break;
 470
 471                 case 0x86DD:
 472                         type = htonl(AF_INET6);
 473                         break;
 474
 475                 default:
 476                         logger(DEBUG_TRAFFIC, LOG_ERR,
 477                                "Unknown address family %x while writing packet to %s %s",
 478                                af, device_info, device);
 479                         return false;
 480                 }
 481
 482                 memcpy(DATA(packet) + 10, &type, sizeof(type));
 483
 484                 if(write(device_fd, DATA(packet) + 10, packet->len - 10) < 0) {
 485                         logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 486                                strerror(errno));
 487                         return false;
 488                 }
 489
 490                 break;
 491         }
 492
 493         case DEVICE_TYPE_TAP:
 494                 if(write(device_fd, DATA(packet), packet->len) < 0) {
 495                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 496                                device, strerror(errno));
 497                         return false;
 498                 }
 499
 500                 break;
 501
 502 #ifdef ENABLE_TUNEMU
 503
 504         case DEVICE_TYPE_TUNEMU:
 505                 if(tunemu_write(DATA(packet) + 14, packet->len - 14) < 0) {
 506                         logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 507                                device, strerror(errno));
 508                         return false;
 509                 }
 510
 511                 break;
 512 #endif
 513
 514         default:
 515                 return false;
 516         }
 517
 518         return true;
 519 }
 520
 521 const devops_t os_devops = {
 522         .setup = setup_device,
 523         .close = close_device,
 524         .read = read_packet,
 525         .write = write_packet,
 526 };