git.meshlink.io Git - meshlink/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 #ifdef HAVE_LINUX_IF_TUN_H
  59                 if (netname != NULL)
  60                         iface = xstrdup(netname);
  61 #else
  62                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
  63 #endif
  64         device_fd = open(device, O_RDWR | O_NONBLOCK);
  65
  66         if(device_fd < 0) {
  67                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
  68                 return false;
  69         }
  70
  71 #ifdef FD_CLOEXEC
  72         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
  73 #endif
  74
  75         struct ifreq ifr = {{{0}}};
  76
  77         get_config_string(lookup_config(config_tree, "DeviceType"), &type);
  78
  79         if(type && strcasecmp(type, "tun") && strcasecmp(type, "tap")) {
  80                 logger(LOG_ERR, "Unknown device type %s!", type);
  81                 return false;
  82         }
  83
  84         if((type && !strcasecmp(type, "tun")) || (!type && routing_mode == RMODE_ROUTER)) {
  85                 ifr.ifr_flags = IFF_TUN;
  86                 device_type = DEVICE_TYPE_TUN;
  87                 device_info = "Linux tun/tap device (tun mode)";
  88         } else {
  89                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  90                 device_type = DEVICE_TYPE_TAP;
  91                 device_info = "Linux tun/tap device (tap mode)";
  92         }
  93
  94 #ifdef IFF_ONE_QUEUE
  95         /* Set IFF_ONE_QUEUE flag... */
  96
  97         bool t1q = false;
  98         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
  99                 ifr.ifr_flags |= IFF_ONE_QUEUE;
 100 #endif
 101
 102         if(iface)
 103                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
 104
 105         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
 106                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 107                 if(iface) free(iface);
 108                 iface = xstrdup(ifrname);
 109         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
 110                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
 111                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 112                 if(iface) free(iface);
 113                 iface = xstrdup(ifrname);
 114         }
 115
 116         logger(LOG_INFO, "%s is a %s", device, device_info);
 117
 118         return true;
 119 }
 120
 121 static void close_device(void) {
 122         close(device_fd);
 123
 124         free(type);
 125         free(device);
 126         free(iface);
 127 }
 128
 129 static bool read_packet(vpn_packet_t *packet) {
 130         int inlen;
 131
 132         switch(device_type) {
 133                 case DEVICE_TYPE_TUN:
 134                         inlen = read(device_fd, packet->data + 10, MTU - 10);
 135
 136                         if(inlen <= 0) {
 137                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 138                                            device_info, device, strerror(errno));
 139                                 return false;
 140                         }
 141
 142                         packet->len = inlen + 10;
 143                         break;
 144                 case DEVICE_TYPE_TAP:
 145                         inlen = read(device_fd, packet->data, MTU);
 146
 147                         if(inlen <= 0) {
 148                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 149                                            device_info, device, strerror(errno));
 150                                 return false;
 151                         }
 152
 153                         packet->len = inlen;
 154                         break;
 155                 default:
 156                         abort();
 157         }
 158
 159         device_in_packets++;
 160         device_in_bytes += packet->len;
 161
 162         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 163                            device_info);
 164
 165         return true;
 166 }
 167
 168 static bool write_packet(vpn_packet_t *packet) {
 169         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 170                            packet->len, device_info);
 171
 172         switch(device_type) {
 173                 case DEVICE_TYPE_TUN:
 174                         packet->data[10] = packet->data[11] = 0;
 175                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 176                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 177                                            strerror(errno));
 178                                 return false;
 179                         }
 180                         break;
 181                 case DEVICE_TYPE_TAP:
 182                         if(write(device_fd, packet->data, packet->len) < 0) {
 183                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 184                                            strerror(errno));
 185                                 return false;
 186                         }
 187                         break;
 188                 default:
 189                         abort();
 190         }
 191
 192         device_out_packets++;
 193         device_out_bytes += packet->len;
 194
 195         return true;
 196 }
 197
 198 static void dump_device_stats(void) {
 199         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 200         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
 201         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
 202 }
 203
 204 const devops_t os_devops = {
 205         .setup = setup_device,
 206         .close = close_device,
 207         .read = read_packet,
 208         .write = write_packet,
 209         .dump_stats = dump_device_stats,
 210 };