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 uint64_t device_in_packets = 0;
  51 uint64_t device_in_bytes = 0;
  52 uint64_t device_out_packets = 0;
  53 uint64_t device_out_bytes = 0;
  54
  55 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         if(routing_mode == RMODE_ROUTER) {
  81                 ifr.ifr_flags = IFF_TUN;
  82                 device_type = DEVICE_TYPE_TUN;
  83                 device_info = "Linux tun/tap device (tun mode)";
  84         } else {
  85                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  86                 device_type = DEVICE_TYPE_TAP;
  87                 device_info = "Linux tun/tap device (tap mode)";
  88         }
  89
  90 #ifdef IFF_ONE_QUEUE
  91         /* Set IFF_ONE_QUEUE flag... */
  92         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  93                 ifr.ifr_flags |= IFF_ONE_QUEUE;
  94 #endif
  95
  96         if(iface)
  97                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  98
  99         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
 100                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 101                 if(iface) free(iface);
 102                 iface = xstrdup(ifrname);
 103         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
 104                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
 105                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 106                 if(iface) free(iface);
 107                 iface = xstrdup(ifrname);
 108         } else
 109 #endif
 110         {
 111                 if(routing_mode == RMODE_ROUTER)
 112                         overwrite_mac = true;
 113                 device_info = "Linux ethertap device";
 114                 device_type = DEVICE_TYPE_ETHERTAP;
 115                 if(iface)
 116                         free(iface);
 117                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
 118         }
 119
 120         logger(LOG_INFO, "%s is a %s", device, device_info);
 121
 122         return true;
 123 }
 124
 125 void close_device(void) {
 126         close(device_fd);
 127
 128         free(device);
 129         free(iface);
 130 }
 131
 132 bool read_packet(vpn_packet_t *packet) {
 133         int inlen;
 134
 135         switch(device_type) {
 136                 case DEVICE_TYPE_TUN:
 137                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 138
 139                         if(inlen <= 0) {
 140                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 141                                            device_info, device, strerror(errno));
 142                                 return false;
 143                         }
 144
 145                         packet->len = inlen + 10;
 146                         break;
 147                 case DEVICE_TYPE_TAP:
 148                         inlen = read(device_fd, packet->data, MTU);
 149
 150                         if(inlen <= 0) {
 151                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 152                                            device_info, device, strerror(errno));
 153                                 return false;
 154                         }
 155
 156                         packet->len = inlen;
 157                         break;
 158                 case DEVICE_TYPE_ETHERTAP:
 159                         inlen = read(device_fd, packet->data - 2, MTU + 2);
 160
 161                         if(inlen <= 0) {
 162                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 163                                            device_info, device, strerror(errno));
 164                                 return false;
 165                         }
 166
 167                         packet->len = inlen - 2;
 168                         break;
 169         }
 170
 171         device_in_packets++;
 172         device_in_bytes += packet->len;
 173
 174         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 175                            device_info);
 176
 177         return true;
 178 }
 179
 180 bool write_packet(vpn_packet_t *packet) {
 181         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 182                            packet->len, device_info);
 183
 184         switch(device_type) {
 185                 case DEVICE_TYPE_TUN:
 186                         packet->data[10] = packet->data[11] = 0;
 187                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 188                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 189                                            strerror(errno));
 190                                 return false;
 191                         }
 192                         break;
 193                 case DEVICE_TYPE_TAP:
 194                         if(write(device_fd, packet->data, packet->len) < 0) {
 195                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 196                                            strerror(errno));
 197                                 return false;
 198                         }
 199                         break;
 200                 case DEVICE_TYPE_ETHERTAP:
 201                         *(short int *)(packet->data - 2) = packet->len;
 202
 203                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 204                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 205                                            strerror(errno));
 206                                 return false;
 207                         }
 208                         break;
 209         }
 210
 211         device_out_packets++;
 212         device_out_bytes += packet->len;
 213
 214         return true;
 215 }
 216
 217 void dump_device_stats(void) {
 218         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 219         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
 220         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
 221 }