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 "../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;
 202
 203 #if defined(HAVE_FDEVNAME)
 204         realname = fdevname(device_fd) ? : device;
 205 #elif defined(HAVE_DEVNAME)
 206         struct stat buf;
 207         if(!fstat(device_fd, &buf))
 208                 realname = devname(buf.st_rdev, S_IFCHR) ? : device;
 209 #else
 210         realname = device;
 211 #endif
 212
 213         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
 214                 iface = xstrdup(strrchr(realname, '/') ? strrchr(realname, '/') + 1 : realname);
 215         else if(strcmp(iface, strrchr(realname, '/') ? strrchr(realname, '/') + 1 : realname))
 216                 logger(DEBUG_ALWAYS, LOG_WARNING, "Warning: Interface does not match Device. $INTERFACE might be set incorrectly.");
 217
 218         // Configure the device as best as we can
 219
 220         switch(device_type) {
 221                 default:
 222                         device_type = DEVICE_TYPE_TUN;
 223                 case DEVICE_TYPE_TUN:
 224 #ifdef TUNSIFHEAD
 225                 {
 226                         const int zero = 0;
 227                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 228                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 229                                 return false;
 230                         }
 231                 }
 232 #endif
 233 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 234                 {
 235                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 236                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 237                 }
 238 #endif
 239
 240                         device_info = "Generic BSD tun device";
 241                         break;
 242                 case DEVICE_TYPE_TUNIFHEAD:
 243 #ifdef TUNSIFHEAD
 244                 {
 245                         const int one = 1;
 246                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 247                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 248                                 return false;
 249                         }
 250                 }
 251 #endif
 252 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 253                 {
 254                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 255                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 256                 }
 257 #endif
 258
 259                         device_info = "Generic BSD tun device";
 260                         break;
 261                 case DEVICE_TYPE_TAP:
 262                         if(routing_mode == RMODE_ROUTER)
 263                                 overwrite_mac = true;
 264                         device_info = "Generic BSD tap device";
 265 #ifdef TAPGIFNAME
 266                         {
 267                                 struct ifreq ifr;
 268                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 269                                         if(iface)
 270                                                 free(iface);
 271                                         iface = xstrdup(ifr.ifr_name);
 272                                 }
 273                         }
 274
 275 #endif
 276                         break;
 277 #ifdef ENABLE_TUNEMU
 278                 case DEVICE_TYPE_TUNEMU:
 279                         device_info = "BSD tunemu device";
 280                         break;
 281 #endif
 282         }
 283
 284 #ifdef SIOCGIFADDR
 285         if(overwrite_mac)
 286                 ioctl(device_fd, SIOCGIFADDR, mymac.x);
 287 #endif
 288
 289         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 290
 291         return true;
 292 }
 293
 294 static void close_device(void) {
 295         switch(device_type) {
 296 #ifdef ENABLE_TUNEMU
 297                 case DEVICE_TYPE_TUNEMU:
 298                         tunemu_close(device_fd);
 299                         break;
 300 #endif
 301                 default:
 302                         close(device_fd);
 303         }
 304         device_fd = -1;
 305
 306         free(device); device = NULL;
 307         free(iface); iface = NULL;
 308         device_info = NULL;
 309 }
 310
 311 static bool read_packet(vpn_packet_t *packet) {
 312         int inlen;
 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                                 inlen = tunemu_read(device_fd, DATA(packet) + 14, MTU - 14);
 320                         else
 321 #endif
 322                                 inlen = read(device_fd, DATA(packet) + 14, MTU - 14);
 323
 324                         if(inlen <= 0) {
 325                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 326                                            device, strerror(errno));
 327                                 return false;
 328                         }
 329
 330                         switch(DATA(packet)[14] >> 4) {
 331                                 case 4:
 332                                         DATA(packet)[12] = 0x08;
 333                                         DATA(packet)[13] = 0x00;
 334                                         break;
 335                                 case 6:
 336                                         DATA(packet)[12] = 0x86;
 337                                         DATA(packet)[13] = 0xDD;
 338                                         break;
 339                                 default:
 340                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 341                                                            "Unknown IP version %d while reading packet from %s %s",
 342                                                            DATA(packet)[14] >> 4, device_info, device);
 343                                         return false;
 344                         }
 345
 346                         memset(DATA(packet), 0, 12);
 347                         packet->len = inlen + 14;
 348                         break;
 349
 350                 case DEVICE_TYPE_UTUN:
 351                 case DEVICE_TYPE_TUNIFHEAD: {
 352                         if((inlen = read(device_fd, DATA(packet) + 10, MTU - 10)) <= 0) {
 353                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 354                                            device, strerror(errno));
 355                                 return false;
 356                         }
 357
 358                         switch (DATA(packet)[14] >> 4) {
 359                                 case 4:
 360                                         DATA(packet)[12] = 0x08;
 361                                         DATA(packet)[13] = 0x00;
 362                                         break;
 363
 364                                 case 6:
 365                                         DATA(packet)[12] = 0x86;
 366                                         DATA(packet)[13] = 0xDD;
 367                                         break;
 368
 369                                 default:
 370                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 371                                                            "Unknown IP version %d while reading packet from %s %s",
 372                                                            DATA(packet)[14] >> 4, device_info, device);
 373                                         return false;
 374                         }
 375
 376                         memset(DATA(packet), 0, 12);
 377                         packet->len = inlen + 10;
 378                         break;
 379                 }
 380
 381                 case DEVICE_TYPE_TAP:
 382                         if((inlen = read(device_fd, DATA(packet), MTU)) <= 0) {
 383                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 384                                            device, strerror(errno));
 385                                 return false;
 386                         }
 387
 388                         packet->len = inlen;
 389                         break;
 390
 391                 default:
 392                         return false;
 393         }
 394
 395         logger(DEBUG_TRAFFIC, 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         logger(DEBUG_TRAFFIC, 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, DATA(packet) + 14, packet->len - 14) < 0) {
 408                                 logger(DEBUG_ALWAYS, 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 = (DATA(packet)[12] << 8) + DATA(packet)[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                                         logger(DEBUG_TRAFFIC, 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(DATA(packet) + 10, &type, sizeof type);
 434
 435                         if(write(device_fd, DATA(packet) + 10, packet->len - 10) < 0) {
 436                                 logger(DEBUG_ALWAYS, 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, DATA(packet), packet->len) < 0) {
 445                                 logger(DEBUG_ALWAYS, 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, 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                         break;
 459 #endif
 460
 461                 default:
 462                         return false;
 463         }
 464
 465         return true;
 466 }
 467
 468 const devops_t os_devops = {
 469         .setup = setup_device,
 470         .close = close_device,
 471         .read = read_packet,
 472         .write = write_packet,
 473 };