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                   2001-2014 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 #define DEFAULT_TUN_DEVICE "/dev/tun0"
  38 #if defined(HAVE_DARWIN) || defined(HAVE_FREEBSD) || defined(HAVE_NETBSD)
  39 #define DEFAULT_TAP_DEVICE "/dev/tap0"
  40 #else
  41 #define DEFAULT_TAP_DEVICE "/dev/tun0"
  42 #endif
  43
  44 typedef enum device_type {
  45         DEVICE_TYPE_TUN,
  46         DEVICE_TYPE_TUNIFHEAD,
  47         DEVICE_TYPE_TAP,
  48 #ifdef ENABLE_TUNEMU
  49         DEVICE_TYPE_TUNEMU,
  50 #endif
  51 } device_type_t;
  52
  53 int device_fd = -1;
  54 char *device = NULL;
  55 char *iface = NULL;
  56 static char *device_info = NULL;
  57 #if defined(ENABLE_TUNEMU)
  58 static device_type_t device_type = DEVICE_TYPE_TUNEMU;
  59 #elif defined(HAVE_OPENBSD) || defined(HAVE_FREEBSD) || defined(HAVE_DRAGONFLY)
  60 static device_type_t device_type = DEVICE_TYPE_TUNIFHEAD;
  61 #else
  62 static device_type_t device_type = DEVICE_TYPE_TUN;
  63 #endif
  64
  65 static bool setup_device(void) {
  66         get_config_string(lookup_config(config_tree, "Device"), &device);
  67
  68         char *type;
  69         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
  70                 if(!strcasecmp(type, "tun"))
  71                         /* use default */;
  72 #ifdef ENABLE_TUNEMU
  73                 else if(!strcasecmp(type, "tunemu"))
  74                         device_type = DEVICE_TYPE_TUNEMU;
  75 #endif
  76                 else if(!strcasecmp(type, "tunnohead"))
  77                         device_type = DEVICE_TYPE_TUN;
  78                 else if(!strcasecmp(type, "tunifhead"))
  79                         device_type = DEVICE_TYPE_TUNIFHEAD;
  80                 else if(!strcasecmp(type, "tap"))
  81                         device_type = DEVICE_TYPE_TAP;
  82                 else {
  83                         logger(DEBUG_ALWAYS, LOG_ERR, "Unknown device type %s!", type);
  84                         return false;
  85                 }
  86         } else {
  87                 if((device && strstr(device, "tap")) || routing_mode != RMODE_ROUTER)
  88                         device_type = DEVICE_TYPE_TAP;
  89         }
  90
  91         if(!device) {
  92                 if(device_type == DEVICE_TYPE_TAP)
  93                         device = xstrdup(DEFAULT_TAP_DEVICE);
  94                 else
  95                         device = xstrdup(DEFAULT_TUN_DEVICE);
  96         }
  97
  98         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  99                 iface = NULL;
 100 #ifndef TAPGIFNAME
 101         if (iface) {
 102                 logger(DEBUG_ALWAYS, LOG_WARNING, "Ignoring specified interface name '%s' as device rename is not supported on this platform", iface);
 103                 free(iface);
 104                 iface = NULL;
 105         }
 106 #endif
 107         if (!iface)
 108                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
 109
 110         switch(device_type) {
 111 #ifdef ENABLE_TUNEMU
 112                 case DEVICE_TYPE_TUNEMU: {
 113                         char dynamic_name[256] = "";
 114                         device_fd = tunemu_open(dynamic_name);
 115                 }
 116                         break;
 117 #endif
 118                 default:
 119                         device_fd = open(device, O_RDWR | O_NONBLOCK);
 120         }
 121
 122         if(device_fd < 0) {
 123                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open %s: %s", device, strerror(errno));
 124                 return false;
 125         }
 126
 127 #ifdef FD_CLOEXEC
 128         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 129 #endif
 130
 131         switch(device_type) {
 132                 default:
 133                         device_type = DEVICE_TYPE_TUN;
 134                 case DEVICE_TYPE_TUN:
 135 #ifdef TUNSIFHEAD
 136                 {
 137                         const int zero = 0;
 138                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 139                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 140                                 return false;
 141                         }
 142                 }
 143 #endif
 144 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 145                 {
 146                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 147                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 148                 }
 149 #endif
 150
 151                         device_info = "Generic BSD tun device";
 152                         break;
 153                 case DEVICE_TYPE_TUNIFHEAD:
 154 #ifdef TUNSIFHEAD
 155                 {
 156                         const int one = 1;
 157                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 158                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 159                                 return false;
 160                         }
 161                 }
 162 #endif
 163 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 164                 {
 165                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 166                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 167                 }
 168 #endif
 169
 170                         device_info = "Generic BSD tun device";
 171                         break;
 172                 case DEVICE_TYPE_TAP:
 173                         if(routing_mode == RMODE_ROUTER)
 174                                 overwrite_mac = true;
 175                         device_info = "Generic BSD tap device";
 176 #ifdef TAPGIFNAME
 177                         {
 178                                 struct ifreq ifr;
 179                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 180                                         if(iface)
 181                                                 free(iface);
 182                                         iface = xstrdup(ifr.ifr_name);
 183                                 }
 184                         }
 185
 186 #endif
 187                         break;
 188 #ifdef ENABLE_TUNEMU
 189                 case DEVICE_TYPE_TUNEMU:
 190                         device_info = "BSD tunemu device";
 191                         break;
 192 #endif
 193         }
 194
 195         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 196
 197         return true;
 198 }
 199
 200 static void close_device(void) {
 201         switch(device_type) {
 202 #ifdef ENABLE_TUNEMU
 203                 case DEVICE_TYPE_TUNEMU:
 204                         tunemu_close(device_fd);
 205                         break;
 206 #endif
 207                 default:
 208                         close(device_fd);
 209         }
 210         device_fd = -1;
 211
 212         free(device); device = NULL;
 213         free(iface); iface = NULL;
 214         device_info = NULL;
 215 }
 216
 217 static bool read_packet(vpn_packet_t *packet) {
 218         int inlen;
 219
 220         switch(device_type) {
 221                 case DEVICE_TYPE_TUN:
 222 #ifdef ENABLE_TUNEMU
 223                 case DEVICE_TYPE_TUNEMU:
 224                         if(device_type == DEVICE_TYPE_TUNEMU)
 225                                 inlen = tunemu_read(device_fd, DATA(packet) + 14, MTU - 14);
 226                         else
 227 #endif
 228                                 inlen = read(device_fd, DATA(packet) + 14, MTU - 14);
 229
 230                         if(inlen <= 0) {
 231                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 232                                            device, strerror(errno));
 233                                 return false;
 234                         }
 235
 236                         switch(DATA(packet)[14] >> 4) {
 237                                 case 4:
 238                                         DATA(packet)[12] = 0x08;
 239                                         DATA(packet)[13] = 0x00;
 240                                         break;
 241                                 case 6:
 242                                         DATA(packet)[12] = 0x86;
 243                                         DATA(packet)[13] = 0xDD;
 244                                         break;
 245                                 default:
 246                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 247                                                            "Unknown IP version %d while reading packet from %s %s",
 248                                                            DATA(packet)[14] >> 4, device_info, device);
 249                                         return false;
 250                         }
 251
 252                         memset(DATA(packet), 0, 12);
 253                         packet->len = inlen + 14;
 254                         break;
 255
 256                 case DEVICE_TYPE_TUNIFHEAD: {
 257                         u_int32_t type;
 258                         struct iovec vector[2] = {{&type, sizeof type}, {DATA(packet) + 14, MTU - 14}};
 259
 260                         if((inlen = readv(device_fd, vector, 2)) <= 0) {
 261                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 262                                            device, strerror(errno));
 263                                 return false;
 264                         }
 265
 266                         switch (ntohl(type)) {
 267                                 case AF_INET:
 268                                         DATA(packet)[12] = 0x08;
 269                                         DATA(packet)[13] = 0x00;
 270                                         break;
 271
 272                                 case AF_INET6:
 273                                         DATA(packet)[12] = 0x86;
 274                                         DATA(packet)[13] = 0xDD;
 275                                         break;
 276
 277                                 default:
 278                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 279                                                            "Unknown address family %x while reading packet from %s %s",
 280                                                            ntohl(type), device_info, device);
 281                                         return false;
 282                         }
 283
 284                         memset(DATA(packet), 0, 12);
 285                         packet->len = inlen + 10;
 286                         break;
 287                 }
 288
 289                 case DEVICE_TYPE_TAP:
 290                         if((inlen = read(device_fd, DATA(packet), MTU)) <= 0) {
 291                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 292                                            device, strerror(errno));
 293                                 return false;
 294                         }
 295
 296                         packet->len = inlen;
 297                         break;
 298
 299                 default:
 300                         return false;
 301         }
 302
 303         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s",
 304                            packet->len, device_info);
 305
 306         return true;
 307 }
 308
 309 static bool write_packet(vpn_packet_t *packet) {
 310         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 311                            packet->len, device_info);
 312
 313         switch(device_type) {
 314                 case DEVICE_TYPE_TUN:
 315                         if(write(device_fd, DATA(packet) + 14, packet->len - 14) < 0) {
 316                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 317                                            device, strerror(errno));
 318                                 return false;
 319                         }
 320                         break;
 321
 322                 case DEVICE_TYPE_TUNIFHEAD: {
 323                         u_int32_t type;
 324                         struct iovec vector[2] = {{&type, sizeof type}, {DATA(packet) + 14, packet->len - 14}};
 325                         int af;
 326
 327                         af = (DATA(packet)[12] << 8) + DATA(packet)[13];
 328
 329                         switch (af) {
 330                                 case 0x0800:
 331                                         type = htonl(AF_INET);
 332                                         break;
 333                                 case 0x86DD:
 334                                         type = htonl(AF_INET6);
 335                                         break;
 336                                 default:
 337                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 338                                                            "Unknown address family %x while writing packet to %s %s",
 339                                                            af, device_info, device);
 340                                         return false;
 341                         }
 342
 343                         if(writev(device_fd, vector, 2) < 0) {
 344                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 345                                            strerror(errno));
 346                                 return false;
 347                         }
 348                         break;
 349                 }
 350
 351                 case DEVICE_TYPE_TAP:
 352                         if(write(device_fd, DATA(packet), packet->len) < 0) {
 353                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 354                                            device, strerror(errno));
 355                                 return false;
 356                         }
 357                         break;
 358
 359 #ifdef ENABLE_TUNEMU
 360                 case DEVICE_TYPE_TUNEMU:
 361                         if(tunemu_write(device_fd, DATA(packet) + 14, packet->len - 14) < 0) {
 362                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 363                                            device, strerror(errno));
 364                                 return false;
 365                         }
 366                         break;
 367 #endif
 368
 369                 default:
 370                         return false;
 371         }
 372
 373         return true;
 374 }
 375
 376 const devops_t os_devops = {
 377         .setup = setup_device,
 378         .close = close_device,
 379         .read = read_packet,
 380         .write = write_packet,
 381 };