git.meshlink.io Git - meshlink/blob - src/bsd/device.c

   1 /*
   2     device.c -- Interaction BSD tun/tap device
   3     Copyright (C) 2001-2005 Ivo Timmermans,
   4                   2001-2013 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_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         char *type;
  67
  68         if(!get_config_string(lookup_config(config_tree, "Device"), &device)) {
  69                 if(routing_mode == RMODE_ROUTER)
  70                         device = xstrdup(DEFAULT_TUN_DEVICE);
  71                 else
  72                         device = xstrdup(DEFAULT_TAP_DEVICE);
  73         }
  74
  75         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  76                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  77
  78         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
  79                 if(!strcasecmp(type, "tun"))
  80                         /* use default */;
  81 #ifdef ENABLE_TUNEMU
  82                 else if(!strcasecmp(type, "tunemu"))
  83                         device_type = DEVICE_TYPE_TUNEMU;
  84 #endif
  85                 else if(!strcasecmp(type, "tunnohead"))
  86                         device_type = DEVICE_TYPE_TUN;
  87                 else if(!strcasecmp(type, "tunifhead"))
  88                         device_type = DEVICE_TYPE_TUNIFHEAD;
  89                 else if(!strcasecmp(type, "tap"))
  90                         device_type = DEVICE_TYPE_TAP;
  91                 else {
  92                         logger(DEBUG_ALWAYS, LOG_ERR, "Unknown device type %s!", type);
  93                         return false;
  94                 }
  95         } else {
  96                 if(strstr(device, "tap") || routing_mode != RMODE_ROUTER)
  97                         device_type = DEVICE_TYPE_TAP;
  98         }
  99
 100         switch(device_type) {
 101 #ifdef ENABLE_TUNEMU
 102                 case DEVICE_TYPE_TUNEMU: {
 103                         char dynamic_name[256] = "";
 104                         device_fd = tunemu_open(dynamic_name);
 105                 }
 106                         break;
 107 #endif
 108                 default:
 109                         device_fd = open(device, O_RDWR | O_NONBLOCK);
 110         }
 111
 112         if(device_fd < 0) {
 113                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open %s: %s", device, strerror(errno));
 114                 return false;
 115         }
 116
 117 #ifdef FD_CLOEXEC
 118         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 119 #endif
 120
 121         switch(device_type) {
 122                 default:
 123                         device_type = DEVICE_TYPE_TUN;
 124                 case DEVICE_TYPE_TUN:
 125 #ifdef TUNSIFHEAD
 126                 {
 127                         const int zero = 0;
 128                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
 129                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 130                                 return false;
 131                         }
 132                 }
 133 #endif
 134 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 135                 {
 136                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 137                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 138                 }
 139 #endif
 140
 141                         device_info = "Generic BSD tun device";
 142                         break;
 143                 case DEVICE_TYPE_TUNIFHEAD:
 144 #ifdef TUNSIFHEAD
 145                 {
 146                         const int one = 1;
 147                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 148                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "ioctl", strerror(errno));
 149                                 return false;
 150                         }
 151                 }
 152 #endif
 153 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 154                 {
 155                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 156                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 157                 }
 158 #endif
 159
 160                         device_info = "Generic BSD tun device";
 161                         break;
 162                 case DEVICE_TYPE_TAP:
 163                         if(routing_mode == RMODE_ROUTER)
 164                                 overwrite_mac = true;
 165                         device_info = "Generic BSD tap device";
 166 #ifdef TAPGIFNAME
 167                         {
 168                                 struct ifreq ifr;
 169                                 if(ioctl(device_fd, TAPGIFNAME, (void*)&ifr) == 0) {
 170                                         if(iface)
 171                                                 free(iface);
 172                                         iface = xstrdup(ifr.ifr_name);
 173                                 }
 174                         }
 175
 176 #endif
 177                         break;
 178 #ifdef ENABLE_TUNEMU
 179                 case DEVICE_TYPE_TUNEMU:
 180                         device_info = "BSD tunemu device";
 181                         break;
 182 #endif
 183         }
 184
 185         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 186
 187         return true;
 188 }
 189
 190 static void close_device(void) {
 191         switch(device_type) {
 192 #ifdef ENABLE_TUNEMU
 193                 case DEVICE_TYPE_TUNEMU:
 194                         tunemu_close(device_fd);
 195                         break;
 196 #endif
 197                 default:
 198                         close(device_fd);
 199         }
 200
 201         free(device);
 202         free(iface);
 203 }
 204
 205 static bool read_packet(vpn_packet_t *packet) {
 206         int inlen;
 207
 208         switch(device_type) {
 209                 case DEVICE_TYPE_TUN:
 210 #ifdef ENABLE_TUNEMU
 211                 case DEVICE_TYPE_TUNEMU:
 212                         if(device_type == DEVICE_TYPE_TUNEMU)
 213                                 inlen = tunemu_read(device_fd, packet->data + 14, MTU - 14);
 214                         else
 215 #endif
 216                                 inlen = read(device_fd, packet->data + 14, MTU - 14);
 217
 218                         if(inlen <= 0) {
 219                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 220                                            device, strerror(errno));
 221                                 return false;
 222                         }
 223
 224                         switch(packet->data[14] >> 4) {
 225                                 case 4:
 226                                         packet->data[12] = 0x08;
 227                                         packet->data[13] = 0x00;
 228                                         break;
 229                                 case 6:
 230                                         packet->data[12] = 0x86;
 231                                         packet->data[13] = 0xDD;
 232                                         break;
 233                                 default:
 234                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 235                                                            "Unknown IP version %d while reading packet from %s %s",
 236                                                            packet->data[14] >> 4, device_info, device);
 237                                         return false;
 238                         }
 239
 240                         memset(packet->data, 0, 12);
 241                         packet->len = inlen + 14;
 242                         break;
 243
 244                 case DEVICE_TYPE_TUNIFHEAD: {
 245                         u_int32_t type;
 246                         struct iovec vector[2] = {{&type, sizeof type}, {packet->data + 14, MTU - 14}};
 247
 248                         if((inlen = readv(device_fd, vector, 2)) <= 0) {
 249                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 250                                            device, strerror(errno));
 251                                 return false;
 252                         }
 253
 254                         switch (ntohl(type)) {
 255                                 case AF_INET:
 256                                         packet->data[12] = 0x08;
 257                                         packet->data[13] = 0x00;
 258                                         break;
 259
 260                                 case AF_INET6:
 261                                         packet->data[12] = 0x86;
 262                                         packet->data[13] = 0xDD;
 263                                         break;
 264
 265                                 default:
 266                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 267                                                            "Unknown address family %x while reading packet from %s %s",
 268                                                            ntohl(type), device_info, device);
 269                                         return false;
 270                         }
 271
 272                         memset(packet->data, 0, 12);
 273                         packet->len = inlen + 10;
 274                         break;
 275                 }
 276
 277                 case DEVICE_TYPE_TAP:
 278                         if((inlen = read(device_fd, packet->data, MTU)) <= 0) {
 279                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 280                                            device, strerror(errno));
 281                                 return false;
 282                         }
 283
 284                         packet->len = inlen;
 285                         break;
 286
 287                 default:
 288                         return false;
 289         }
 290
 291         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s",
 292                            packet->len, device_info);
 293
 294         return true;
 295 }
 296
 297 static bool write_packet(vpn_packet_t *packet) {
 298         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 299                            packet->len, device_info);
 300
 301         switch(device_type) {
 302                 case DEVICE_TYPE_TUN:
 303                         if(write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 304                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 305                                            device, strerror(errno));
 306                                 return false;
 307                         }
 308                         break;
 309
 310                 case DEVICE_TYPE_TUNIFHEAD: {
 311                         u_int32_t type;
 312                         struct iovec vector[2] = {{&type, sizeof type}, {packet->data + 14, packet->len - 14}};
 313                         int af;
 314
 315                         af = (packet->data[12] << 8) + packet->data[13];
 316
 317                         switch (af) {
 318                                 case 0x0800:
 319                                         type = htonl(AF_INET);
 320                                         break;
 321                                 case 0x86DD:
 322                                         type = htonl(AF_INET6);
 323                                         break;
 324                                 default:
 325                                         logger(DEBUG_TRAFFIC, LOG_ERR,
 326                                                            "Unknown address family %x while writing packet to %s %s",
 327                                                            af, device_info, device);
 328                                         return false;
 329                         }
 330
 331                         if(writev(device_fd, vector, 2) < 0) {
 332                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 333                                            strerror(errno));
 334                                 return false;
 335                         }
 336                         break;
 337                 }
 338
 339                 case DEVICE_TYPE_TAP:
 340                         if(write(device_fd, packet->data, packet->len) < 0) {
 341                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 342                                            device, strerror(errno));
 343                                 return false;
 344                         }
 345                         break;
 346
 347 #ifdef ENABLE_TUNEMU
 348                 case DEVICE_TYPE_TUNEMU:
 349                         if(tunemu_write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 350                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info,
 351                                            device, strerror(errno));
 352                                 return false;
 353                         }
 354                         break;
 355 #endif
 356
 357                 default:
 358                         return false;
 359         }
 360
 361         return true;
 362 }
 363
 364 const devops_t os_devops = {
 365         .setup = setup_device,
 366         .close = close_device,
 367         .read = read_packet,
 368         .write = write_packet,
 369 };