src/bsd/device.c

   1 /*
   2     device.c -- Interaction BSD tun/tap device
   3     Copyright (C) 2001-2005 Ivo Timmermans,
   4                   2001-2009 Guus Sliepen <guus@tinc-vpn.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id: device.c 1398 2004-11-01 15:18:53Z guus $
  21 */
  22
  23 #include "system.h"
  24
  25 #include "conf.h"
  26 #include "logger.h"
  27 #include "net.h"
  28 #include "route.h"
  29 #include "utils.h"
  30 #include "xalloc.h"
  31
  32 #define DEFAULT_DEVICE "/dev/tun0"
  33
  34 typedef enum device_type {
  35         DEVICE_TYPE_TUN,
  36         DEVICE_TYPE_TUNIFHEAD,
  37         DEVICE_TYPE_TAP,
  38 } device_type_t;
  39
  40 int device_fd = -1;
  41 char *device = NULL;
  42 char *iface = NULL;
  43 static char *device_info = NULL;
  44 static int device_total_in = 0;
  45 static int device_total_out = 0;
  46 #if defined(HAVE_OPENBSD) || defined(HAVE_FREEBSD)
  47 static device_type_t device_type = DEVICE_TYPE_TUNIFHEAD;
  48 #else
  49 static device_type_t device_type = DEVICE_TYPE_TUN;
  50 #endif
  51
  52 bool setup_device(void) {
  53         char *type;
  54
  55         cp();
  56
  57         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  58                 device = xstrdup(DEFAULT_DEVICE);
  59
  60         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  61                 iface = xstrdup(rindex(device, '/') ? rindex(device, '/') + 1 : device);
  62
  63         if((device_fd = open(device, O_RDWR | O_NONBLOCK)) < 0) {
  64                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  65                 return false;
  66         }
  67
  68         if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
  69                 if(!strcasecmp(type, "tun"))
  70                         /* use default */;
  71                 else if(!strcasecmp(type, "tunnohead"))
  72                         device_type = DEVICE_TYPE_TUN;
  73                 else if(!strcasecmp(type, "tunifhead"))
  74                         device_type = DEVICE_TYPE_TUNIFHEAD;
  75                 else if(!strcasecmp(type, "tap"))
  76                         device_type = DEVICE_TYPE_TAP;
  77                 else {
  78                         logger(LOG_ERR, _("Unknown device type %s!"), type);
  79                         return false;
  80                 }
  81         } else {
  82                 if(strstr(device, "tap") || routing_mode != RMODE_ROUTER)
  83                         device_type = DEVICE_TYPE_TAP;
  84         }
  85
  86         switch(device_type) {
  87                 default:
  88                         device_type = DEVICE_TYPE_TUN;
  89                 case DEVICE_TYPE_TUN:
  90 #ifdef TUNSIFHEAD
  91                 {
  92                         const int zero = 0;
  93                         if(ioctl(device_fd, TUNSIFHEAD, &zero, sizeof zero) == -1) {
  94                                 logger(LOG_ERR, _("System call `%s' failed: %s"), "ioctl", strerror(errno));
  95                                 return false;
  96                         }
  97                 }
  98 #endif
  99 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 100                 {
 101                         const int mode = IFF_BROADCAST | IFF_MULTICAST;
 102                         ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 103                 }
 104 #endif
 105
 106                         device_info = _("Generic BSD tun device");
 107                         break;
 108                 case DEVICE_TYPE_TUNIFHEAD:
 109 #ifdef TUNSIFHEAD
 110                 {
 111                         const int one = 1;
 112                         if(ioctl(device_fd, TUNSIFHEAD, &one, sizeof one) == -1) {
 113                                 logger(LOG_ERR, _("System call `%s' failed: %s"), "ioctl", strerror(errno));
 114                                 return false;
 115                         }
 116                 }
 117 #endif
 118 #if defined(TUNSIFMODE) && defined(IFF_BROADCAST) && defined(IFF_MULTICAST)
 119                 {
 120                                 const int mode = IFF_BROADCAST | IFF_MULTICAST;
 121                                 ioctl(device_fd, TUNSIFMODE, &mode, sizeof mode);
 122                 }
 123 #endif
 124
 125                         device_info = _("Generic BSD tun device");
 126                         break;
 127                 case DEVICE_TYPE_TAP:
 128                         if(routing_mode == RMODE_ROUTER)
 129                                 overwrite_mac = true;
 130                         device_info = _("Generic BSD tap device");
 131                         break;
 132         }
 133
 134         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 135
 136         return true;
 137 }
 138
 139 void close_device(void) {
 140         cp();
 141
 142         close(device_fd);
 143
 144         free(device);
 145         free(iface);
 146 }
 147
 148 bool read_packet(vpn_packet_t *packet) {
 149         int lenin;
 150
 151         cp();
 152
 153         switch(device_type) {
 154                 case DEVICE_TYPE_TUN:
 155                         if((lenin = read(device_fd, packet->data + 14, MTU - 14)) <= 0) {
 156                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"), device_info,
 157                                            device, strerror(errno));
 158                                 return false;
 159                         }
 160
 161                         switch(packet->data[14] >> 4) {
 162                                 case 4:
 163                                         packet->data[12] = 0x08;
 164                                         packet->data[13] = 0x00;
 165                                         break;
 166                                 case 6:
 167                                         packet->data[12] = 0x86;
 168                                         packet->data[13] = 0xDD;
 169                                         break;
 170                                 default:
 171                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 172                                                            _ ("Unknown IP version %d while reading packet from %s %s"),
 173                                                            packet->data[14] >> 4, device_info, device);
 174                                         return false;
 175                         }
 176
 177                         packet->len = lenin + 14;
 178                         break;
 179
 180                 case DEVICE_TYPE_TUNIFHEAD: {
 181                         u_int32_t type;
 182                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, MTU - 14}};
 183
 184                         if((lenin = readv(device_fd, vector, 2)) <= 0) {
 185                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"), device_info,
 186                                            device, strerror(errno));
 187                                 return false;
 188                         }
 189
 190                         switch (ntohl(type)) {
 191                                 case AF_INET:
 192                                         packet->data[12] = 0x08;
 193                                         packet->data[13] = 0x00;
 194                                         break;
 195
 196                                 case AF_INET6:
 197                                         packet->data[12] = 0x86;
 198                                         packet->data[13] = 0xDD;
 199                                         break;
 200
 201                                 default:
 202                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 203                                                            _ ("Unknown address family %x while reading packet from %s %s"),
 204                                                            ntohl(type), device_info, device);
 205                                         return false;
 206                         }
 207
 208                         packet->len = lenin + 10;
 209                         break;
 210                 }
 211
 212                 case DEVICE_TYPE_TAP:
 213                         if((lenin = read(device_fd, packet->data, MTU)) <= 0) {
 214                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"), device_info,
 215                                            device, strerror(errno));
 216                                 return false;
 217                         }
 218
 219                         packet->len = lenin;
 220                         break;
 221
 222                 default:
 223                         return false;
 224         }
 225
 226         device_total_in += packet->len;
 227
 228         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"),
 229                            packet->len, device_info);
 230
 231         return true;
 232 }
 233
 234 bool write_packet(vpn_packet_t *packet)
 235 {
 236         cp();
 237
 238         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 239                            packet->len, device_info);
 240
 241         switch(device_type) {
 242                 case DEVICE_TYPE_TUN:
 243                         if(write(device_fd, packet->data + 14, packet->len - 14) < 0) {
 244                                 logger(LOG_ERR, _("Error while writing to %s %s: %s"), device_info,
 245                                            device, strerror(errno));
 246                                 return false;
 247                         }
 248                         break;
 249
 250                 case DEVICE_TYPE_TUNIFHEAD: {
 251                         u_int32_t type;
 252                         struct iovec vector[2] = {{&type, sizeof(type)}, {packet->data + 14, packet->len - 14}};
 253                         int af;
 254
 255                         af = (packet->data[12] << 8) + packet->data[13];
 256
 257                         switch (af) {
 258                                 case 0x0800:
 259                                         type = htonl(AF_INET);
 260                                         break;
 261                                 case 0x86DD:
 262                                         type = htonl(AF_INET6);
 263                                         break;
 264                                 default:
 265                                         ifdebug(TRAFFIC) logger(LOG_ERR,
 266                                                            _("Unknown address family %x while writing packet to %s %s"),
 267                                                            af, device_info, device);
 268                                         return false;
 269                         }
 270
 271                         if(writev(device_fd, vector, 2) < 0) {
 272                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 273                                            strerror(errno));
 274                                 return false;
 275                         }
 276                         break;
 277                 }
 278
 279                 case DEVICE_TYPE_TAP:
 280                         if(write(device_fd, packet->data, packet->len) < 0) {
 281                                 logger(LOG_ERR, _("Error while writing to %s %s: %s"), device_info,
 282                                            device, strerror(errno));
 283                                 return false;
 284                         }
 285                         break;
 286
 287                 default:
 288                         return false;
 289         }
 290
 291         device_total_out += packet->len;
 292
 293         return true;
 294 }
 295
 296 void dump_device_stats(void)
 297 {
 298         cp();
 299
 300         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 301         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 302         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 303 }