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                   2001-2012 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 *type = NULL;
  49 static char ifrname[IFNAMSIZ];
  50 static char *device_info;
  51
  52 static uint64_t device_total_in = 0;
  53 static uint64_t device_total_out = 0;
  54
  55 static bool setup_device(void) {
  56         struct ifreq ifr;
  57         bool t1q = false;
  58
  59         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  60                 device = xstrdup(DEFAULT_DEVICE);
  61
  62         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  63 #ifdef HAVE_LINUX_IF_TUN_H
  64                 if (netname != NULL)
  65                         iface = xstrdup(netname);
  66 #else
  67                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  68 #endif
  69         device_fd = open(device, O_RDWR | O_NONBLOCK);
  70
  71         if(device_fd < 0) {
  72                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  73                 return false;
  74         }
  75
  76 #ifdef HAVE_LINUX_IF_TUN_H
  77         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  78
  79         memset(&ifr, 0, sizeof(ifr));
  80
  81         get_config_string(lookup_config(config_tree, "DeviceType"), &type);
  82
  83         if(type && strcasecmp(type, "tun") && strcasecmp(type, "tap")) {
  84                 logger(LOG_ERR, "Unknown device type %s!", type);
  85                 return false;
  86         }
  87
  88         if((type && !strcasecmp(type, "tun")) || (!type && routing_mode == RMODE_ROUTER)) {
  89                 ifr.ifr_flags = IFF_TUN;
  90                 device_type = DEVICE_TYPE_TUN;
  91                 device_info = "Linux tun/tap device (tun mode)";
  92         } else {
  93                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  94                 device_type = DEVICE_TYPE_TAP;
  95                 device_info = "Linux tun/tap device (tap mode)";
  96         }
  97
  98 #ifdef IFF_ONE_QUEUE
  99         /* Set IFF_ONE_QUEUE flag... */
 100         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
 101                 ifr.ifr_flags |= IFF_ONE_QUEUE;
 102 #endif
 103
 104         if(iface)
 105                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
 106
 107         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
 108                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 109                 if(iface) free(iface);
 110                 iface = xstrdup(ifrname);
 111         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
 112                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
 113                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 114                 if(iface) free(iface);
 115                 iface = xstrdup(ifrname);
 116         } else
 117 #endif
 118         {
 119                 if(routing_mode == RMODE_ROUTER)
 120                         overwrite_mac = true;
 121                 device_info = "Linux ethertap device";
 122                 device_type = DEVICE_TYPE_ETHERTAP;
 123                 if(iface)
 124                         free(iface);
 125                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
 126         }
 127
 128         logger(LOG_INFO, "%s is a %s", device, device_info);
 129
 130         return true;
 131 }
 132
 133 static void close_device(void) {
 134         close(device_fd);
 135
 136         free(type);
 137         free(device);
 138         free(iface);
 139 }
 140
 141 static bool read_packet(vpn_packet_t *packet) {
 142         int lenin;
 143
 144         switch(device_type) {
 145                 case DEVICE_TYPE_TUN:
 146                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 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 + 10;
 155                         break;
 156                 case DEVICE_TYPE_TAP:
 157                         lenin = read(device_fd, packet->data, MTU);
 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;
 166                         break;
 167                 case DEVICE_TYPE_ETHERTAP:
 168                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 169
 170                         if(lenin <= 0) {
 171                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 172                                            device_info, device, strerror(errno));
 173                                 return false;
 174                         }
 175
 176                         packet->len = lenin - 2;
 177                         break;
 178         }
 179
 180         device_total_in += packet->len;
 181
 182         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 183                            device_info);
 184
 185         return true;
 186 }
 187
 188 static bool write_packet(vpn_packet_t *packet) {
 189         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 190                            packet->len, device_info);
 191
 192         switch(device_type) {
 193                 case DEVICE_TYPE_TUN:
 194                         packet->data[10] = packet->data[11] = 0;
 195                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 196                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 197                                            strerror(errno));
 198                                 return false;
 199                         }
 200                         break;
 201                 case DEVICE_TYPE_TAP:
 202                         if(write(device_fd, packet->data, packet->len) < 0) {
 203                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 204                                            strerror(errno));
 205                                 return false;
 206                         }
 207                         break;
 208                 case DEVICE_TYPE_ETHERTAP:
 209                         *(short int *)(packet->data - 2) = packet->len;
 210
 211                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 212                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 213                                            strerror(errno));
 214                                 return false;
 215                         }
 216                         break;
 217         }
 218
 219         device_total_out += packet->len;
 220
 221         return true;
 222 }
 223
 224 static void dump_device_stats(void) {
 225         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 226         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 227         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 228 }
 229
 230 const devops_t os_devops = {
 231         .setup = setup_device,
 232         .close = close_device,
 233         .read = read_packet,
 234         .write = write_packet,
 235         .dump_stats = dump_device_stats,
 236 };