git.meshlink.io Git - meshlink/blob - 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 #include "device.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 uint64_t device_in_packets = 0;
  52 uint64_t device_in_bytes = 0;
  53 uint64_t device_out_packets = 0;
  54 uint64_t device_out_bytes = 0;
  55
  56 bool setup_device(void) {
  57         struct ifreq ifr;
  58         bool t1q = false;
  59
  60         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  61                 device = xstrdup(DEFAULT_DEVICE);
  62
  63         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
  64 #ifdef HAVE_LINUX_IF_TUN_H
  65                 if (netname != NULL)
  66                         iface = xstrdup(netname);
  67 #else
  68                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  69 #endif
  70         device_fd = open(device, O_RDWR | O_NONBLOCK);
  71
  72         if(device_fd < 0) {
  73                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  74                 return false;
  75         }
  76
  77 #ifdef HAVE_LINUX_IF_TUN_H
  78         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  79
  80         memset(&ifr, 0, sizeof ifr);
  81         if(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         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  94                 ifr.ifr_flags |= IFF_ONE_QUEUE;
  95 #endif
  96
  97         if(iface)
  98                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  99
 100         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
 101                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 102                 if(iface) free(iface);
 103                 iface = xstrdup(ifrname);
 104         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
 105                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
 106                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 107                 if(iface) free(iface);
 108                 iface = xstrdup(ifrname);
 109         } else
 110 #endif
 111         {
 112                 if(routing_mode == RMODE_ROUTER)
 113                         overwrite_mac = true;
 114                 device_info = "Linux ethertap device";
 115                 device_type = DEVICE_TYPE_ETHERTAP;
 116                 if(iface)
 117                         free(iface);
 118                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
 119         }
 120
 121         logger(LOG_INFO, "%s is a %s", device, device_info);
 122
 123         return true;
 124 }
 125
 126 void close_device(void) {
 127         close(device_fd);
 128
 129         free(device);
 130         free(iface);
 131 }
 132
 133 bool read_packet(vpn_packet_t *packet) {
 134         int inlen;
 135
 136         switch(device_type) {
 137                 case DEVICE_TYPE_TUN:
 138                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 139
 140                         if(inlen <= 0) {
 141                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 142                                            device_info, device, strerror(errno));
 143                                 return false;
 144                         }
 145
 146                         packet->len = inlen + 10;
 147                         break;
 148                 case DEVICE_TYPE_TAP:
 149                         inlen = read(device_fd, packet->data, MTU);
 150
 151                         if(inlen <= 0) {
 152                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 153                                            device_info, device, strerror(errno));
 154                                 return false;
 155                         }
 156
 157                         packet->len = inlen;
 158                         break;
 159                 case DEVICE_TYPE_ETHERTAP:
 160                         inlen = read(device_fd, packet->data - 2, MTU + 2);
 161
 162                         if(inlen <= 0) {
 163                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 164                                            device_info, device, strerror(errno));
 165                                 return false;
 166                         }
 167
 168                         packet->len = inlen - 2;
 169                         break;
 170         }
 171
 172         device_in_packets++;
 173         device_in_bytes += packet->len;
 174
 175         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 176                            device_info);
 177
 178         return true;
 179 }
 180
 181 bool write_packet(vpn_packet_t *packet) {
 182         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 183                            packet->len, device_info);
 184
 185         switch(device_type) {
 186                 case DEVICE_TYPE_TUN:
 187                         packet->data[10] = packet->data[11] = 0;
 188                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 189                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 190                                            strerror(errno));
 191                                 return false;
 192                         }
 193                         break;
 194                 case DEVICE_TYPE_TAP:
 195                         if(write(device_fd, packet->data, packet->len) < 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_ETHERTAP:
 202                         *(short int *)(packet->data - 2) = packet->len;
 203
 204                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 205                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 206                                            strerror(errno));
 207                                 return false;
 208                         }
 209                         break;
 210         }
 211
 212         device_out_packets++;
 213         device_out_bytes += packet->len;
 214
 215         return true;
 216 }
 217
 218 void dump_device_stats(void) {
 219         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 220         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
 221         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
 222 }