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 #include <linux/if_tun.h>
  24 #define DEFAULT_DEVICE "/dev/net/tun"
  25
  26 #include "conf.h"
  27 #include "device.h"
  28 #include "logger.h"
  29 #include "net.h"
  30 #include "route.h"
  31 #include "utils.h"
  32 #include "xalloc.h"
  33 #include "device.h"
  34
  35 typedef enum device_type_t {
  36         DEVICE_TYPE_TUN,
  37         DEVICE_TYPE_TAP,
  38 } device_type_t;
  39
  40 int device_fd = -1;
  41 static device_type_t device_type;
  42 char *device = NULL;
  43 char *iface = NULL;
  44 static char *type = NULL;
  45 static char ifrname[IFNAMSIZ];
  46 static char *device_info;
  47
  48 uint64_t device_in_packets = 0;
  49 uint64_t device_in_bytes = 0;
  50 uint64_t device_out_packets = 0;
  51 uint64_t device_out_bytes = 0;
  52
  53 static bool setup_device(void) {
  54         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  55                 device = xstrdup(DEFAULT_DEVICE);
  56
  57         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  58                 if(netname)
  59                         iface = xstrdup(netname);
  60
  61         device_fd = open(device, O_RDWR | O_NONBLOCK);
  62
  63         if(device_fd < 0) {
  64                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  65                 return false;
  66         }
  67
  68 #ifdef FD_CLOEXEC
  69         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
  70 #endif
  71
  72         struct ifreq ifr = {{{0}}};
  73
  74         get_config_string(lookup_config(config_tree, "DeviceType"), &type);
  75
  76         if(type && strcasecmp(type, "tun") && strcasecmp(type, "tap")) {
  77                 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown device type %s!", type);
  78                 return false;
  79         }
  80
  81         if((type && !strcasecmp(type, "tun")) || (!type && routing_mode == RMODE_ROUTER)) {
  82                 ifr.ifr_flags = IFF_TUN;
  83                 device_type = DEVICE_TYPE_TUN;
  84                 device_info = "Linux tun/tap device (tun mode)";
  85         } else {
  86                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  87                 device_type = DEVICE_TYPE_TAP;
  88                 device_info = "Linux tun/tap device (tap mode)";
  89         }
  90
  91 #ifdef IFF_ONE_QUEUE
  92         /* Set IFF_ONE_QUEUE flag... */
  93
  94         bool t1q = false;
  95         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  96                 ifr.ifr_flags |= IFF_ONE_QUEUE;
  97 #endif
  98
  99         if(iface)
 100                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
 101
 102         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
 103                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 104                 free(iface);
 105                 iface = xstrdup(ifrname);
 106         }
 107
 108         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 109
 110         return true;
 111 }
 112
 113 static void close_device(void) {
 114         close(device_fd);
 115
 116         free(type);
 117         free(device);
 118         free(iface);
 119 }
 120
 121 static bool read_packet(vpn_packet_t *packet) {
 122         int inlen;
 123
 124         switch(device_type) {
 125                 case DEVICE_TYPE_TUN:
 126                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 127
 128                         if(inlen <= 0) {
 129                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s",
 130                                            device_info, device, strerror(errno));
 131                                 return false;
 132                         }
 133
 134                         memset(packet->data, 0, 12);
 135                         packet->len = inlen + 10;
 136                         break;
 137                 case DEVICE_TYPE_TAP:
 138                         inlen = read(device_fd, packet->data, MTU);
 139
 140                         if(inlen <= 0) {
 141                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s",
 142                                            device_info, device, strerror(errno));
 143                                 return false;
 144                         }
 145
 146                         packet->len = inlen;
 147                         break;
 148                 default:
 149                         abort();
 150         }
 151
 152         device_in_packets++;
 153         device_in_bytes += packet->len;
 154
 155         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 156                            device_info);
 157
 158         return true;
 159 }
 160
 161 static bool write_packet(vpn_packet_t *packet) {
 162         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 163                            packet->len, device_info);
 164
 165         switch(device_type) {
 166                 case DEVICE_TYPE_TUN:
 167                         packet->data[10] = packet->data[11] = 0;
 168                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 169                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 170                                            strerror(errno));
 171                                 return false;
 172                         }
 173                         break;
 174                 case DEVICE_TYPE_TAP:
 175                         if(write(device_fd, packet->data, packet->len) < 0) {
 176                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 177                                            strerror(errno));
 178                                 return false;
 179                         }
 180                         break;
 181                 default:
 182                         abort();
 183         }
 184
 185         device_out_packets++;
 186         device_out_bytes += packet->len;
 187
 188         return true;
 189 }
 190
 191 static void dump_device_stats(void) {
 192         logger(DEBUG_ALWAYS, LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 193         logger(DEBUG_ALWAYS, LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
 194         logger(DEBUG_ALWAYS, LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
 195 }
 196
 197 const devops_t os_devops = {
 198         .setup = setup_device,
 199         .close = close_device,
 200         .read = read_packet,
 201         .write = write_packet,
 202         .dump_stats = dump_device_stats,
 203 };