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                   2001-2013 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 "names.h"
  30 #include "net.h"
  31 #include "route.h"
  32 #include "utils.h"
  33 #include "xalloc.h"
  34 #include "device.h"
  35
  36 typedef enum device_type_t {
  37         DEVICE_TYPE_TUN,
  38         DEVICE_TYPE_TAP,
  39 } device_type_t;
  40
  41 int device_fd = -1;
  42 static device_type_t device_type;
  43 char *device = NULL;
  44 char *iface = NULL;
  45 static char *type = NULL;
  46 static char ifrname[IFNAMSIZ];
  47 static char *device_info;
  48
  49 uint64_t device_in_packets = 0;
  50 uint64_t device_in_bytes = 0;
  51 uint64_t device_out_packets = 0;
  52 uint64_t device_out_bytes = 0;
  53
  54 static bool setup_device(void) {
  55         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  56                 device = xstrdup(DEFAULT_DEVICE);
  57
  58         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  59                 if(netname)
  60                         iface = xstrdup(netname);
  61
  62         device_fd = open(device, O_RDWR | O_NONBLOCK);
  63
  64         if(device_fd < 0) {
  65                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  66                 return false;
  67         }
  68
  69 #ifdef FD_CLOEXEC
  70         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
  71 #endif
  72
  73         struct ifreq ifr = {{{0}}};
  74
  75         get_config_string(lookup_config(config_tree, "DeviceType"), &type);
  76
  77         if(type && strcasecmp(type, "tun") && strcasecmp(type, "tap")) {
  78                 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown device type %s!", type);
  79                 return false;
  80         }
  81
  82         if((type && !strcasecmp(type, "tun")) || (!type && routing_mode == RMODE_ROUTER)) {
  83                 ifr.ifr_flags = IFF_TUN;
  84                 device_type = DEVICE_TYPE_TUN;
  85                 device_info = "Linux tun/tap device (tun mode)";
  86         } else {
  87                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  88                 device_type = DEVICE_TYPE_TAP;
  89                 device_info = "Linux tun/tap device (tap mode)";
  90         }
  91
  92 #ifdef IFF_ONE_QUEUE
  93         /* Set IFF_ONE_QUEUE flag... */
  94
  95         bool t1q = false;
  96         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  97                 ifr.ifr_flags |= IFF_ONE_QUEUE;
  98 #endif
  99
 100         if(iface)
 101                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
 102
 103         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
 104                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 105                 free(iface);
 106                 iface = xstrdup(ifrname);
 107         }
 108
 109         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 110
 111         return true;
 112 }
 113
 114 static void close_device(void) {
 115         close(device_fd);
 116
 117         free(type);
 118         free(device);
 119         free(iface);
 120 }
 121
 122 static bool read_packet(vpn_packet_t *packet) {
 123         int inlen;
 124
 125         switch(device_type) {
 126                 case DEVICE_TYPE_TUN:
 127                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 128
 129                         if(inlen <= 0) {
 130                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s",
 131                                            device_info, device, strerror(errno));
 132                                 return false;
 133                         }
 134
 135                         memset(packet->data, 0, 12);
 136                         packet->len = inlen + 10;
 137                         break;
 138                 case DEVICE_TYPE_TAP:
 139                         inlen = read(device_fd, packet->data, MTU);
 140
 141                         if(inlen <= 0) {
 142                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s",
 143                                            device_info, device, strerror(errno));
 144                                 return false;
 145                         }
 146
 147                         packet->len = inlen;
 148                         break;
 149                 default:
 150                         abort();
 151         }
 152
 153         device_in_packets++;
 154         device_in_bytes += packet->len;
 155
 156         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 157                            device_info);
 158
 159         return true;
 160 }
 161
 162 static bool write_packet(vpn_packet_t *packet) {
 163         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 164                            packet->len, device_info);
 165
 166         switch(device_type) {
 167                 case DEVICE_TYPE_TUN:
 168                         packet->data[10] = packet->data[11] = 0;
 169                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 170                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 171                                            strerror(errno));
 172                                 return false;
 173                         }
 174                         break;
 175                 case DEVICE_TYPE_TAP:
 176                         if(write(device_fd, packet->data, packet->len) < 0) {
 177                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 178                                            strerror(errno));
 179                                 return false;
 180                         }
 181                         break;
 182                 default:
 183                         abort();
 184         }
 185
 186         device_out_packets++;
 187         device_out_bytes += packet->len;
 188
 189         return true;
 190 }
 191
 192 static void dump_device_stats(void) {
 193         logger(DEBUG_ALWAYS, LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 194         logger(DEBUG_ALWAYS, LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
 195         logger(DEBUG_ALWAYS, LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
 196 }
 197
 198 const devops_t os_devops = {
 199         .setup = setup_device,
 200         .close = close_device,
 201         .read = read_packet,
 202         .write = write_packet,
 203         .dump_stats = dump_device_stats,
 204 };