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                   2001-2011 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 "device.h"
  32 #include "logger.h"
  33 #include "net.h"
  34 #include "route.h"
  35 #include "utils.h"
  36 #include "xalloc.h"
  37
  38 typedef enum device_type_t {
  39         DEVICE_TYPE_ETHERTAP,
  40         DEVICE_TYPE_TUN,
  41         DEVICE_TYPE_TAP,
  42 } device_type_t;
  43
  44 int device_fd = -1;
  45 static device_type_t device_type;
  46 char *device = NULL;
  47 char *iface = NULL;
  48 static char ifrname[IFNAMSIZ];
  49 static char *device_info;
  50
  51 static uint64_t device_total_in = 0;
  52 static uint64_t device_total_out = 0;
  53
  54 static bool setup_device(void) {
  55         struct ifreq ifr;
  56         bool t1q = false;
  57
  58         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  59                 device = xstrdup(DEFAULT_DEVICE);
  60
  61         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  62 #ifdef HAVE_LINUX_IF_TUN_H
  63                 if (netname != NULL)
  64                         iface = xstrdup(netname);
  65 #else
  66                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  67 #endif
  68         device_fd = open(device, O_RDWR | O_NONBLOCK);
  69
  70         if(device_fd < 0) {
  71                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  72                 return false;
  73         }
  74
  75 #ifdef HAVE_LINUX_IF_TUN_H
  76         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  77
  78         memset(&ifr, 0, sizeof(ifr));
  79         if(routing_mode == RMODE_ROUTER) {
  80                 ifr.ifr_flags = IFF_TUN;
  81                 device_type = DEVICE_TYPE_TUN;
  82                 device_info = "Linux tun/tap device (tun mode)";
  83         } else {
  84                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  85                 device_type = DEVICE_TYPE_TAP;
  86                 device_info = "Linux tun/tap device (tap mode)";
  87         }
  88
  89 #ifdef IFF_ONE_QUEUE
  90         /* Set IFF_ONE_QUEUE flag... */
  91         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  92                 ifr.ifr_flags |= IFF_ONE_QUEUE;
  93 #endif
  94
  95         if(iface)
  96                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  97
  98         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
  99                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 100                 if(iface) free(iface);
 101                 iface = xstrdup(ifrname);
 102         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
 103                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
 104                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 105                 if(iface) free(iface);
 106                 iface = xstrdup(ifrname);
 107         } else
 108 #endif
 109         {
 110                 if(routing_mode == RMODE_ROUTER)
 111                         overwrite_mac = true;
 112                 device_info = "Linux ethertap device";
 113                 device_type = DEVICE_TYPE_ETHERTAP;
 114                 if(iface)
 115                         free(iface);
 116                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
 117         }
 118
 119         logger(LOG_INFO, "%s is a %s", device, device_info);
 120
 121         return true;
 122 }
 123
 124 static void close_device(void) {
 125         close(device_fd);
 126
 127         free(device);
 128         free(iface);
 129 }
 130
 131 static bool read_packet(vpn_packet_t *packet) {
 132         int lenin;
 133
 134         switch(device_type) {
 135                 case DEVICE_TYPE_TUN:
 136                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 137
 138                         if(lenin <= 0) {
 139                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 140                                            device_info, device, strerror(errno));
 141                                 return false;
 142                         }
 143
 144                         packet->len = lenin + 10;
 145                         break;
 146                 case DEVICE_TYPE_TAP:
 147                         lenin = read(device_fd, packet->data, MTU);
 148
 149                         if(lenin <= 0) {
 150                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 151                                            device_info, device, strerror(errno));
 152                                 return false;
 153                         }
 154
 155                         packet->len = lenin;
 156                         break;
 157                 case DEVICE_TYPE_ETHERTAP:
 158                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 159
 160                         if(lenin <= 0) {
 161                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 162                                            device_info, device, strerror(errno));
 163                                 return false;
 164                         }
 165
 166                         packet->len = lenin - 2;
 167                         break;
 168         }
 169
 170         device_total_in += packet->len;
 171
 172         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 173                            device_info);
 174
 175         return true;
 176 }
 177
 178 static bool write_packet(vpn_packet_t *packet) {
 179         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 180                            packet->len, device_info);
 181
 182         switch(device_type) {
 183                 case DEVICE_TYPE_TUN:
 184                         packet->data[10] = packet->data[11] = 0;
 185                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 186                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 187                                            strerror(errno));
 188                                 return false;
 189                         }
 190                         break;
 191                 case DEVICE_TYPE_TAP:
 192                         if(write(device_fd, packet->data, packet->len) < 0) {
 193                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 194                                            strerror(errno));
 195                                 return false;
 196                         }
 197                         break;
 198                 case DEVICE_TYPE_ETHERTAP:
 199                         *(short int *)(packet->data - 2) = packet->len;
 200
 201                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 202                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 203                                            strerror(errno));
 204                                 return false;
 205                         }
 206                         break;
 207         }
 208
 209         device_total_out += packet->len;
 210
 211         return true;
 212 }
 213
 214 static void dump_device_stats(void) {
 215         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 216         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 217         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 218 }
 219
 220 const devops_t os_devops = {
 221         .setup = setup_device,
 222         .close = close_device,
 223         .read = read_packet,
 224         .write = write_packet,
 225         .dump_stats = dump_device_stats,
 226 };