www.tinc-vpn.org Git - tinc/blob - src/linux/device.c

   1 /*
   2     device.c -- Interaction with Linux ethertap and 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 along
  17     with this program; if not, write to the Free Software Foundation, Inc.,
  18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21 #include "system.h"
  22
  23 #ifdef HAVE_LINUX_IF_TUN_H
  24 #include <linux/if_tun.h>
  25 #define DEFAULT_DEVICE "/dev/net/tun"
  26 #else
  27 #define DEFAULT_DEVICE "/dev/tap0"
  28 #endif
  29
  30 #include "conf.h"
  31 #include "logger.h"
  32 #include "net.h"
  33 #include "route.h"
  34 #include "utils.h"
  35 #include "xalloc.h"
  36
  37 typedef enum device_type_t {
  38         DEVICE_TYPE_ETHERTAP,
  39         DEVICE_TYPE_TUN,
  40         DEVICE_TYPE_TAP,
  41 } device_type_t;
  42
  43 int device_fd = -1;
  44 static device_type_t device_type;
  45 char *device = NULL;
  46 char *iface = NULL;
  47 static char ifrname[IFNAMSIZ];
  48 static char *device_info;
  49
  50 static uint64_t device_total_in = 0;
  51 static uint64_t device_total_out = 0;
  52
  53 bool setup_device(void) {
  54         struct ifreq ifr;
  55         bool t1q = false;
  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 #ifdef HAVE_LINUX_IF_TUN_H
  62                 if (netname != NULL)
  63                         iface = xstrdup(netname);
  64 #else
  65                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  66 #endif
  67         device_fd = open(device, O_RDWR | O_NONBLOCK);
  68
  69         if(device_fd < 0) {
  70                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  71                 return false;
  72         }
  73
  74 #ifdef HAVE_LINUX_IF_TUN_H
  75         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  76
  77         memset(&ifr, 0, sizeof(ifr));
  78         if(routing_mode == RMODE_ROUTER) {
  79                 ifr.ifr_flags = IFF_TUN;
  80                 device_type = DEVICE_TYPE_TUN;
  81                 device_info = "Linux tun/tap device (tun mode)";
  82         } else {
  83                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  84                 device_type = DEVICE_TYPE_TAP;
  85                 device_info = "Linux tun/tap device (tap mode)";
  86         }
  87
  88 #ifdef IFF_ONE_QUEUE
  89         /* Set IFF_ONE_QUEUE flag... */
  90         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  91                 ifr.ifr_flags |= IFF_ONE_QUEUE;
  92 #endif
  93
  94         if(iface)
  95                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  96
  97         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
  98                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
  99                 if(iface) free(iface);
 100                 iface = xstrdup(ifrname);
 101         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
 102                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
 103                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 104                 if(iface) free(iface);
 105                 iface = xstrdup(ifrname);
 106         } else
 107 #endif
 108         {
 109                 if(routing_mode == RMODE_ROUTER)
 110                         overwrite_mac = true;
 111                 device_info = "Linux ethertap device";
 112                 device_type = DEVICE_TYPE_ETHERTAP;
 113                 if(iface)
 114                         free(iface);
 115                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
 116         }
 117
 118         logger(LOG_INFO, "%s is a %s", device, device_info);
 119
 120         return true;
 121 }
 122
 123 void close_device(void) {
 124         close(device_fd);
 125
 126         free(device);
 127         free(iface);
 128 }
 129
 130 bool read_packet(vpn_packet_t *packet) {
 131         int lenin;
 132
 133         switch(device_type) {
 134                 case DEVICE_TYPE_TUN:
 135                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 136
 137                         if(lenin <= 0) {
 138                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 139                                            device_info, device, strerror(errno));
 140                                 return false;
 141                         }
 142
 143                         packet->len = lenin + 10;
 144                         break;
 145                 case DEVICE_TYPE_TAP:
 146                         lenin = read(device_fd, packet->data, MTU);
 147
 148                         if(lenin <= 0) {
 149                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 150                                            device_info, device, strerror(errno));
 151                                 return false;
 152                         }
 153
 154                         packet->len = lenin;
 155                         break;
 156                 case DEVICE_TYPE_ETHERTAP:
 157                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 158
 159                         if(lenin <= 0) {
 160                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 161                                            device_info, device, strerror(errno));
 162                                 return false;
 163                         }
 164
 165                         packet->len = lenin - 2;
 166                         break;
 167         }
 168
 169         device_total_in += packet->len;
 170
 171         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 172                            device_info);
 173
 174         return true;
 175 }
 176
 177 bool write_packet(vpn_packet_t *packet) {
 178         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 179                            packet->len, device_info);
 180
 181         switch(device_type) {
 182                 case DEVICE_TYPE_TUN:
 183                         packet->data[10] = packet->data[11] = 0;
 184                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 185                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 186                                            strerror(errno));
 187                                 return false;
 188                         }
 189                         break;
 190                 case DEVICE_TYPE_TAP:
 191                         if(write(device_fd, packet->data, packet->len) < 0) {
 192                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 193                                            strerror(errno));
 194                                 return false;
 195                         }
 196                         break;
 197                 case DEVICE_TYPE_ETHERTAP:
 198                         *(short int *)(packet->data - 2) = packet->len;
 199
 200                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 201                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 202                                            strerror(errno));
 203                                 return false;
 204                         }
 205                         break;
 206         }
 207
 208         device_total_out += packet->len;
 209
 210         return true;
 211 }
 212
 213 void dump_device_stats(void) {
 214         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 215         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 216         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 217 }