www.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                   2001-2014 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 "../device.h"
  32 #include "../logger.h"
  33 #include "../net.h"
  34 #include "../route.h"
  35 #include "../utils.h"
  36 #include "../xalloc.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 *type = NULL;
  49 static char ifrname[IFNAMSIZ];
  50 static char *device_info;
  51
  52 static uint64_t device_total_in = 0;
  53 static uint64_t device_total_out = 0;
  54
  55 static 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 FD_CLOEXEC
  77         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
  78 #endif
  79
  80 #ifdef HAVE_LINUX_IF_TUN_H
  81         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  82
  83         memset(&ifr, 0, sizeof(ifr));
  84
  85         get_config_string(lookup_config(config_tree, "DeviceType"), &type);
  86
  87         if(type && strcasecmp(type, "tun") && strcasecmp(type, "tap")) {
  88                 logger(LOG_ERR, "Unknown device type %s!", type);
  89                 return false;
  90         }
  91
  92         if((type && !strcasecmp(type, "tun")) || (!type && routing_mode == RMODE_ROUTER)) {
  93                 ifr.ifr_flags = IFF_TUN;
  94                 device_type = DEVICE_TYPE_TUN;
  95                 device_info = "Linux tun/tap device (tun mode)";
  96         } else {
  97                 if (routing_mode == RMODE_ROUTER)
  98                         overwrite_mac = true;
  99                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 100                 device_type = DEVICE_TYPE_TAP;
 101                 device_info = "Linux tun/tap device (tap mode)";
 102         }
 103
 104 #ifdef IFF_ONE_QUEUE
 105         /* Set IFF_ONE_QUEUE flag... */
 106         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
 107                 ifr.ifr_flags |= IFF_ONE_QUEUE;
 108 #endif
 109
 110         if(iface) {
 111                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
 112                 ifr.ifr_name[IFNAMSIZ - 1] = 0;
 113         }
 114
 115         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
 116                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 117                 ifrname[IFNAMSIZ - 1] = 0;
 118                 free(iface);
 119                 iface = xstrdup(ifrname);
 120         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
 121                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
 122                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 123                 ifrname[IFNAMSIZ - 1] = 0;
 124                 free(iface);
 125                 iface = xstrdup(ifrname);
 126         } else
 127 #endif
 128         {
 129                 if(routing_mode == RMODE_ROUTER)
 130                         overwrite_mac = true;
 131                 device_info = "Linux ethertap device";
 132                 device_type = DEVICE_TYPE_ETHERTAP;
 133                 free(iface);
 134                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
 135         }
 136
 137         if(overwrite_mac && !ioctl(device_fd, SIOCGIFHWADDR, &ifr))
 138                 memcpy(mymac.x, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
 139
 140         logger(LOG_INFO, "%s is a %s", device, device_info);
 141
 142         return true;
 143 }
 144
 145 static void close_device(void) {
 146         close(device_fd);
 147
 148         free(type);
 149         free(device);
 150         free(iface);
 151 }
 152
 153 static bool read_packet(vpn_packet_t *packet) {
 154         int lenin;
 155
 156         switch(device_type) {
 157                 case DEVICE_TYPE_TUN:
 158                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 159
 160                         if(lenin <= 0) {
 161                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 162                                            device_info, device, strerror(errno));
 163                                 return false;
 164                         }
 165
 166                         memset(packet->data, 0, 12);
 167                         packet->len = lenin + 10;
 168                         break;
 169                 case DEVICE_TYPE_TAP:
 170                         lenin = read(device_fd, packet->data, MTU);
 171
 172                         if(lenin <= 0) {
 173                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 174                                            device_info, device, strerror(errno));
 175                                 return false;
 176                         }
 177
 178                         packet->len = lenin;
 179                         break;
 180                 case DEVICE_TYPE_ETHERTAP:
 181                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 182
 183                         if(lenin <= 0) {
 184                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
 185                                            device_info, device, strerror(errno));
 186                                 return false;
 187                         }
 188
 189                         packet->len = lenin - 2;
 190                         break;
 191         }
 192
 193         device_total_in += packet->len;
 194
 195         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 196                            device_info);
 197
 198         return true;
 199 }
 200
 201 static bool write_packet(vpn_packet_t *packet) {
 202         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 203                            packet->len, device_info);
 204
 205         switch(device_type) {
 206                 case DEVICE_TYPE_TUN:
 207                         packet->data[10] = packet->data[11] = 0;
 208                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 209                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 210                                            strerror(errno));
 211                                 return false;
 212                         }
 213                         break;
 214                 case DEVICE_TYPE_TAP:
 215                         if(write(device_fd, packet->data, packet->len) < 0) {
 216                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 217                                            strerror(errno));
 218                                 return false;
 219                         }
 220                         break;
 221                 case DEVICE_TYPE_ETHERTAP:
 222                         memcpy(packet->data - 2, &packet->len, 2);
 223
 224                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 225                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 226                                            strerror(errno));
 227                                 return false;
 228                         }
 229                         break;
 230         }
 231
 232         device_total_out += packet->len;
 233
 234         return true;
 235 }
 236
 237 static void dump_device_stats(void) {
 238         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 239         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 240         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 241 }
 242
 243 const devops_t os_devops = {
 244         .setup = setup_device,
 245         .close = close_device,
 246         .read = read_packet,
 247         .write = write_packet,
 248         .dump_stats = dump_device_stats,
 249 };