src/linux/device.c

   1 /*
   2     device.c -- Interaction with Linux ethertap and tun/tap device
   3     Copyright (C) 2001-2002 Ivo Timmermans <ivo@o2w.nl>,
   4                   2001-2002 Guus Sliepen <guus@sliepen.eu.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
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id: device.c,v 1.1.2.16 2003/07/06 22:11:35 guus Exp $
  21 */
  22
  23 #include "config.h"
  24
  25 #include <stdio.h>
  26 #include <errno.h>
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <fcntl.h>
  30 #include <net/if.h>
  31 #include <unistd.h>
  32 #include <string.h>
  33 #include <sys/ioctl.h>
  34
  35 #ifdef HAVE_TUNTAP
  36 #ifdef LINUX_IF_TUN_H
  37 #include LINUX_IF_TUN_H
  38 #else
  39 #include <linux/if_tun.h>
  40 #endif
  41 #define DEFAULT_DEVICE "/dev/net/tun"
  42 #else
  43 #define DEFAULT_DEVICE "/dev/tap0"
  44 #endif
  45
  46 #include <utils.h>
  47 #include "conf.h"
  48 #include "net.h"
  49 #include "route.h"
  50 #include "logger.h"
  51
  52 #include "system.h"
  53
  54 enum {
  55         DEVICE_TYPE_ETHERTAP,
  56         DEVICE_TYPE_TUN,
  57         DEVICE_TYPE_TAP,
  58 };
  59
  60 int device_fd = -1;
  61 int device_type;
  62 char *device;
  63 char *interface;
  64 char ifrname[IFNAMSIZ];
  65 char *device_info;
  66
  67 int device_total_in = 0;
  68 int device_total_out = 0;
  69
  70 /*
  71   open the local ethertap device
  72 */
  73 int setup_device(void)
  74 {
  75         struct ifreq ifr;
  76
  77         cp();
  78
  79         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  80                 device = DEFAULT_DEVICE;
  81
  82         if(!get_config_string(lookup_config(config_tree, "Interface"), &interface))
  83 #ifdef HAVE_TUNTAP
  84                 interface = netname;
  85 #else
  86                 interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
  87 #endif
  88         device_fd = open(device, O_RDWR | O_NONBLOCK);
  89
  90         if(device_fd < 0) {
  91                 logger(DEBUG_ALWAYS, LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  92                 return -1;
  93         }
  94
  95 #ifdef HAVE_TUNTAP
  96         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  97
  98         memset(&ifr, 0, sizeof(ifr));
  99         if(routing_mode == RMODE_ROUTER) {
 100                 ifr.ifr_flags = IFF_TUN;
 101                 device_type = DEVICE_TYPE_TUN;
 102                 device_info = _("Linux tun/tap device (tun mode)");
 103         } else {
 104                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 105                 device_type = DEVICE_TYPE_TAP;
 106                 device_info = _("Linux tun/tap device (tap mode)");
 107         }
 108
 109         if(interface)
 110                 strncpy(ifr.ifr_name, interface, IFNAMSIZ);
 111
 112         if(!ioctl(device_fd, TUNSETIFF, (void *) &ifr)) {
 113                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 114                 interface = ifrname;
 115         } else if(!ioctl(device_fd, (('T' << 8) | 202), (void *) &ifr)) {
 116                 logger(DEBUG_ALWAYS, LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
 117                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 118                 interface = ifrname;
 119         } else
 120 #endif
 121         {
 122                 if(routing_mode == RMODE_ROUTER)
 123                         overwrite_mac = 1;
 124                 device_info = _("Linux ethertap device");
 125                 device_type = DEVICE_TYPE_ETHERTAP;
 126                 interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
 127         }
 128
 129         logger(DEBUG_ALWAYS, LOG_INFO, _("%s is a %s"), device, device_info);
 130
 131         return 0;
 132 }
 133
 134 void close_device(void)
 135 {
 136         cp();
 137
 138         close(device_fd);
 139 }
 140
 141 /*
 142   read, encrypt and send data that is
 143   available through the ethertap device
 144 */
 145 int read_packet(vpn_packet_t *packet)
 146 {
 147         int lenin;
 148
 149         cp();
 150
 151         switch(device_type) {
 152                 case DEVICE_TYPE_TUN:
 153                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 154
 155                         if(lenin <= 0) {
 156                                 logger(DEBUG_ALWAYS, LOG_ERR, _("Error while reading from %s %s: %s"),
 157                                            device_info, device, strerror(errno));
 158                                 return -1;
 159                         }
 160
 161                         packet->len = lenin + 10;
 162                         break;
 163                 case DEVICE_TYPE_TAP:
 164                         lenin = read(device_fd, packet->data, MTU);
 165
 166                         if(lenin <= 0) {
 167                                 logger(DEBUG_ALWAYS, LOG_ERR, _("Error while reading from %s %s: %s"),
 168                                            device_info, device, strerror(errno));
 169                                 return -1;
 170                         }
 171
 172                         packet->len = lenin;
 173                         break;
 174                 case DEVICE_TYPE_ETHERTAP:
 175                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 176
 177                         if(lenin <= 0) {
 178                                 logger(DEBUG_ALWAYS, LOG_ERR, _("Error while reading from %s %s: %s"),
 179                                            device_info, device, strerror(errno));
 180                                 return -1;
 181                         }
 182
 183                         packet->len = lenin - 2;
 184                         break;
 185         }
 186
 187         device_total_in += packet->len;
 188
 189         logger(DEBUG_TRAFFIC, LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 190                            device_info);
 191
 192         return 0;
 193 }
 194
 195 int write_packet(vpn_packet_t *packet)
 196 {
 197         cp();
 198
 199         logger(DEBUG_TRAFFIC, LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 200                            packet->len, device_info);
 201
 202         switch(device_type) {
 203                 case DEVICE_TYPE_TUN:
 204                         packet->data[10] = packet->data[11] = 0;
 205                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 206                                 logger(DEBUG_ALWAYS, LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 207                                            strerror(errno));
 208                                 return -1;
 209                         }
 210                         break;
 211                 case DEVICE_TYPE_TAP:
 212                         if(write(device_fd, packet->data, packet->len) < 0) {
 213                                 logger(DEBUG_ALWAYS, LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 214                                            strerror(errno));
 215                                 return -1;
 216                         }
 217                         break;
 218                 case DEVICE_TYPE_ETHERTAP:
 219                         *(short int *)(packet->data - 2) = packet->len;
 220
 221                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 222                                 logger(DEBUG_ALWAYS, LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 223                                            strerror(errno));
 224                                 return -1;
 225                         }
 226                         break;
 227         }
 228
 229         device_total_out += packet->len;
 230
 231         return 0;
 232 }
 233
 234 void dump_device_stats(void)
 235 {
 236         cp();
 237
 238         logger(DEBUG_ALWAYS, LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 239         logger(DEBUG_ALWAYS, LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 240         logger(DEBUG_ALWAYS, LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 241 }