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                   2001-2017 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 "../names.h"
  28 #include "../net.h"
  29 #include "../route.h"
  30 #include "../utils.h"
  31 #include "../xalloc.h"
  32
  33 #ifdef ENABLE_TUNEMU
  34 #include "bsd/tunemu.h"
  35 #endif
  36
  37 #ifdef HAVE_NET_IF_UTUN_H
  38 #include <sys/sys_domain.h>
  39 #include <sys/kern_control.h>
  40 #include <net/if_utun.h>
  41 #endif
  42
  43 #define DEFAULT_TUN_DEVICE "/dev/tun0"
  44 #define DEFAULT_TAP_DEVICE "/dev/tap0"
  45
  46 typedef enum device_type {
  47         DEVICE_TYPE_TUN,
  48         DEVICE_TYPE_TUNIFHEAD,
  49         DEVICE_TYPE_TAP,
  50 #ifdef ENABLE_TUNEMU
  51         DEVICE_TYPE_TUNEMU,
  52 #endif
  53         DEVICE_TYPE_UTUN,
  54 } device_type_t;
  55
  56 int device_fd = -1;
  57 char *device = NULL;
  58 char *iface = NULL;
  59 static char *device_info = NULL;
  60 #if defined(ENABLE_TUNEMU)
  61 static device_type_t device_type = DEVICE_TYPE_TUNEMU;
  62 #elif defined(HAVE_OPENBSD) || defined(HAVE_FREEBSD) || defined(HAVE_DRAGONFLY)
  63 static device_type_t device_type = DEVICE_TYPE_TUNIFHEAD;
  64 #else
  65 static device_type_t device_type = DEVICE_TYPE_TUN;
  66 #endif
  67
  68 #ifdef HAVE_NET_IF_UTUN_H
  69 static bool setup_utun(void) {
  70         device_fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
  71         if(device_fd == -1) {
  72                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open PF_SYSTEM socket: %s\n", strerror(errno));
  73                 return false;
  74         }
  75
  76         struct ctl_info info = {};
  77         strlcpy(info.ctl_name, UTUN_CONTROL_NAME, sizeof info.ctl_name);
  78
  79         if(ioctl(device_fd, CTLIOCGINFO, &info) == -1) {
  80                 logger(DEBUG_ALWAYS, LOG_ERR, "ioctl(CTLIOCGINFO) failed: %s", strerror(errno));
  81                 return false;
  82         }
  83
  84         int unit = -1;
  85         char *p = strstr(device, "utun"), *e = NULL;
  86         if(p) {
  87                 unit = strtol(p + 4, &e, 10);
  88                 if(!e)
  89                         unit = -1;
  90         }
  91
  92         struct sockaddr_ctl sc = {
  93                 .sc_id = info.ctl_id,
  94                 .sc_len = sizeof sc,
  95                 .sc_family = AF_SYSTEM,
  96                 .ss_sysaddr = AF_SYS_CONTROL,
  97                 .sc_unit = unit + 1,
  98         };
  99
 100         if(connect(device_fd, (struct sockaddr *)&sc, sizeof(sc)) == -1) {
 101                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not connect utun socket: %s\n", strerror(errno));
 102                 return false;
 103         }
 104
 105         char name[64] = "";
 106         socklen_t len = sizeof name;
 107         if(getsockopt(device_fd, SYSPROTO_CONTROL, UTUN_OPT_IFNAME, name, &len)) {
 108                 iface = xstrdup(device);
 109         } else {
 110                 iface = xstrdup(name);
 111         }
 112
 113         device_info = "OS X utun device";
 114
 115         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 116
 117         return true;
 118 }
 119 #endif
 120
 121 static bool setup_device(void) {
 122         get_config_string(lookup_config(config_tree, "Device"), &device);
 123
 124         // Find out if it's supposed to be a tun or a tap device
 125
 126         char *type;
 127         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
 128                 if(!strcasecmp(type, "tun"))
 129                         /* use default */;
 130 #ifdef ENABLE_TUNEMU
 131                 else if(!strcasecmp(type, "tunemu"))
 132                         device_type = DEVICE_TYPE_TUNEMU;
 133 #endif
 134 #ifdef HAVE_NET_IF_UTUN_H
 135                 else if(!strcasecmp(type, "utun"))
 136                         device_type = DEVICE_TYPE_UTUN;
 137 #endif
 138                 else if(!strcasecmp(type, "tunnohead"))
 139                         device_type = DEVICE_TYPE_TUN;
 140                 else if(!strcasecmp(type, "tunifhead"))
 141                         device_type = DEVICE_TYPE_TUNIFHEAD;
 142                 else if(!strcasecmp(type, "tap"))
 143                         device_type = DEVICE_TYPE_TAP;
 144                 else {
 145                         logger(DEBUG_ALWAYS, LOG_ERR, "Unknown device type %s!", type);
 146                         return false;
 147                 }
 148         } else {
 149 #ifdef HAVE_NET_IF_UTUN_H
 150                 if(device && (strncmp(device, "utun", 4) == 0 || strncmp(device, "/dev/utun", 9) == 0))
 151                         device_type = DEVICE_TYPE_UTUN;
 152                 else
 153 #endif
 154                 if((device && strstr(device, "tap")) || routing_mode != RMODE_ROUTER)
 155                         device_type = DEVICE_TYPE_TAP;
 156         }
 157
 158         if(routing_mode == RMODE_SWITCH && device_type != DEVICE_TYPE_TAP) {
 159                 logger(DEBUG_ALWAYS, LOG_ERR, "Only tap devices support switch mode!");
 160                 return false;
 161         }
 162
 163         // Find out which device file to open
 164
 165         if(!device) {
 166                 if(device_type == DEVICE_TYPE_TAP)
 167                         device = xstrdup(DEFAULT_TAP_DEVICE);
 168                 else
 169                         device = xstrdup(DEFAULT_TUN_DEVICE);
 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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(DEBUG_ALWAYS, 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         device_fd = -1;
 306
 307         free(device); device = NULL;
 308         free(iface); iface = NULL;
 309         device_info = NULL;
 310 }
 311
 312 static bool read_packet(vpn_packet_t *packet) {
 313         int inlen;
 314
 315         switch(device_type) {
 316                 case DEVICE_TYPE_TUN:
 317 #ifdef ENABLE_TUNEMU
 318                 case DEVICE_TYPE_TUNEMU:
 319                         if(device_type == DEVICE_TYPE_TUNEMU)
 320                                 inlen = tunemu_read(device_fd, DATA(packet) + 14, MTU - 14);
 321                         else
 322 #endif
 323                                 inlen = read(device_fd, DATA(packet) + 14, MTU - 14);
 324
 325                         if(inlen <= 0) {
 326                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 327                                            device, strerror(errno));
 328                                 return false;
 329                         }
 330
 331                         switch(DATA(packet)[14] >> 4) {
 332                                 case 4:
 333                                         DATA(packet)[12] = 0x08;
 334                                         DATA(packet)[13] = 0x00;
 335                                         break;
 336                                 case 6:
 337                                         DATA(packet)[12] = 0x86;
 338                                         DATA(packet)[13] = 0xDD;
 339                                         break;
 340                                 default:
 341                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 342                                                            "Unknown IP version %d while reading packet from %s %s",
 343                                                            DATA(packet)[14] >> 4, device_info, device);
 344                                         return false;
 345                         }
 346
 347                         memset(DATA(packet), 0, 12);
 348                         packet->len = inlen + 14;
 349                         break;
 350
 351                 case DEVICE_TYPE_UTUN:
 352                 case DEVICE_TYPE_TUNIFHEAD: {
 353                         if((inlen = read(device_fd, DATA(packet) + 10, MTU - 10)) <= 0) {
 354                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 355                                            device, strerror(errno));
 356                                 return false;
 357                         }
 358
 359                         switch (DATA(packet)[14] >> 4) {
 360                                 case 4:
 361                                         DATA(packet)[12] = 0x08;
 362                                         DATA(packet)[13] = 0x00;
 363                                         break;
 364
 365                                 case 6:
 366                                         DATA(packet)[12] = 0x86;
 367                                         DATA(packet)[13] = 0xDD;
 368                                         break;
 369
 370                                 default:
 371                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 372                                                            "Unknown IP version %d while reading packet from %s %s",
 373                                                            DATA(packet)[14] >> 4, device_info, device);
 374                                         return false;
 375                         }
 376
 377                         memset(DATA(packet), 0, 12);
 378                         packet->len = inlen + 10;
 379                         break;
 380                 }
 381
 382                 case DEVICE_TYPE_TAP:
 383                         if((inlen = read(device_fd, DATA(packet), MTU)) <= 0) {
 384                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 385                                            device, strerror(errno));
 386                                 return false;
 387                         }
 388
 389                         packet->len = inlen;
 390                         break;
 391
 392                 default:
 393                         return false;
 394         }
 395
 396         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s",
 397                            packet->len, device_info);
 398
 399         return true;
 400 }
 401
 402 static bool write_packet(vpn_packet_t *packet) {
 403         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 404                            packet->len, device_info);
 405
 406         switch(device_type) {
 407                 case DEVICE_TYPE_TUN:
 408                         if(write(device_fd, DATA(packet) + 14, packet->len - 14) < 0) {
 409                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 410                                            device, strerror(errno));
 411                                 return false;
 412                         }
 413                         break;
 414
 415                 case DEVICE_TYPE_UTUN:
 416                 case DEVICE_TYPE_TUNIFHEAD: {
 417                         int af = (DATA(packet)[12] << 8) + DATA(packet)[13];
 418                         uint32_t type;
 419
 420                         switch (af) {
 421                                 case 0x0800:
 422                                         type = htonl(AF_INET);
 423                                         break;
 424                                 case 0x86DD:
 425                                         type = htonl(AF_INET6);
 426                                         break;
 427                                 default:
 428                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 429                                                            "Unknown address family %x while writing packet to %s %s",
 430                                                            af, device_info, device);
 431                                         return false;
 432                         }
 433
 434                         memcpy(DATA(packet) + 10, &type, sizeof type);
 435
 436                         if(write(device_fd, DATA(packet) + 10, packet->len - 10) < 0) {
 437                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 438                                            strerror(errno));
 439                                 return false;
 440                         }
 441                         break;
 442                 }
 443
 444                 case DEVICE_TYPE_TAP:
 445                         if(write(device_fd, DATA(packet), packet->len) < 0) {
 446                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 447                                            device, strerror(errno));
 448                                 return false;
 449                         }
 450                         break;
 451
 452 #ifdef ENABLE_TUNEMU
 453                 case DEVICE_TYPE_TUNEMU:
 454                         if(tunemu_write(device_fd, DATA(packet) + 14, packet->len - 14) < 0) {
 455                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 456                                            device, strerror(errno));
 457                                 return false;
 458                         }
 459                         break;
 460 #endif
 461
 462                 default:
 463                         return false;
 464         }
 465
 466         return true;
 467 }
 468
 469 const devops_t os_devops = {
 470         .setup = setup_device,
 471         .close = close_device,
 472         .read = read_packet,
 473         .write = write_packet,
 474 };