src/linux/device.c

   1 /*
   2     device.c -- Interaction with Linux ethertap and tun/tap device
   3     Copyright (C) 2001-2003 Ivo Timmermans <ivo@o2w.nl>,
   4                   2001-2003 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 1.1.2.17 2003/07/12 17:41:48 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 int setup_device(void)
  71 {
  72         struct ifreq ifr;
  73
  74         cp();
  75
  76         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  77                 device = DEFAULT_DEVICE;
  78
  79         if(!get_config_string(lookup_config(config_tree, "Interface"), &interface))
  80 #ifdef HAVE_TUNTAP
  81                 interface = netname;
  82 #else
  83                 interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
  84 #endif
  85         device_fd = open(device, O_RDWR | O_NONBLOCK);
  86
  87         if(device_fd < 0) {
  88                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  89                 return -1;
  90         }
  91
  92 #ifdef HAVE_TUNTAP
  93         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  94
  95         memset(&ifr, 0, sizeof(ifr));
  96         if(routing_mode == RMODE_ROUTER) {
  97                 ifr.ifr_flags = IFF_TUN;
  98                 device_type = DEVICE_TYPE_TUN;
  99                 device_info = _("Linux tun/tap device (tun mode)");
 100         } else {
 101                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 102                 device_type = DEVICE_TYPE_TAP;
 103                 device_info = _("Linux tun/tap device (tap mode)");
 104         }
 105
 106         if(interface)
 107                 strncpy(ifr.ifr_name, interface, IFNAMSIZ);
 108
 109         if(!ioctl(device_fd, TUNSETIFF, (void *) &ifr)) {
 110                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 111                 interface = ifrname;
 112         } else if(!ioctl(device_fd, (('T' << 8) | 202), (void *) &ifr)) {
 113                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
 114                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 115                 interface = ifrname;
 116         } else
 117 #endif
 118         {
 119                 if(routing_mode == RMODE_ROUTER)
 120                         overwrite_mac = 1;
 121                 device_info = _("Linux ethertap device");
 122                 device_type = DEVICE_TYPE_ETHERTAP;
 123                 interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
 124         }
 125
 126         logger(LOG_INFO, _("%s is a %s"), device, device_info);
 127
 128         return 0;
 129 }
 130
 131 void close_device(void)
 132 {
 133         cp();
 134
 135         close(device_fd);
 136 }
 137
 138 int read_packet(vpn_packet_t *packet)
 139 {
 140         int lenin;
 141
 142         cp();
 143
 144         switch(device_type) {
 145                 case DEVICE_TYPE_TUN:
 146                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 147
 148                         if(lenin <= 0) {
 149                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 150                                            device_info, device, strerror(errno));
 151                                 return -1;
 152                         }
 153
 154                         packet->len = lenin + 10;
 155                         break;
 156                 case DEVICE_TYPE_TAP:
 157                         lenin = read(device_fd, packet->data, MTU);
 158
 159                         if(lenin <= 0) {
 160                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 161                                            device_info, device, strerror(errno));
 162                                 return -1;
 163                         }
 164
 165                         packet->len = lenin;
 166                         break;
 167                 case DEVICE_TYPE_ETHERTAP:
 168                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 169
 170                         if(lenin <= 0) {
 171                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
 172                                            device_info, device, strerror(errno));
 173                                 return -1;
 174                         }
 175
 176                         packet->len = lenin - 2;
 177                         break;
 178         }
 179
 180         device_total_in += packet->len;
 181
 182         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 183                            device_info);
 184
 185         return 0;
 186 }
 187
 188 int write_packet(vpn_packet_t *packet)
 189 {
 190         cp();
 191
 192         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 193                            packet->len, device_info);
 194
 195         switch(device_type) {
 196                 case DEVICE_TYPE_TUN:
 197                         packet->data[10] = packet->data[11] = 0;
 198                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 199                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 200                                            strerror(errno));
 201                                 return -1;
 202                         }
 203                         break;
 204                 case DEVICE_TYPE_TAP:
 205                         if(write(device_fd, packet->data, packet->len) < 0) {
 206                                 logger(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_ETHERTAP:
 212                         *(short int *)(packet->data - 2) = packet->len;
 213
 214                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 215                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 216                                            strerror(errno));
 217                                 return -1;
 218                         }
 219                         break;
 220         }
 221
 222         device_total_out += packet->len;
 223
 224         return 0;
 225 }
 226
 227 void dump_device_stats(void)
 228 {
 229         cp();
 230
 231         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 232         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 233         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 234 }