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 1.1.2.15 2003/06/11 19:28:37 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 <syslog.h>
  33 #include <string.h>
  34 #include <sys/ioctl.h>
  35
  36 #ifdef HAVE_TUNTAP
  37 #ifdef LINUX_IF_TUN_H
  38 #include LINUX_IF_TUN_H
  39 #else
  40 #include <linux/if_tun.h>
  41 #endif
  42 #define DEFAULT_DEVICE "/dev/net/tun"
  43 #else
  44 #define DEFAULT_DEVICE "/dev/tap0"
  45 #endif
  46
  47 #include <utils.h>
  48 #include "conf.h"
  49 #include "net.h"
  50 #include "subnet.h"
  51 #include "route.h"
  52
  53 #include "system.h"
  54
  55 enum {
  56         DEVICE_TYPE_ETHERTAP,
  57         DEVICE_TYPE_TUN,
  58         DEVICE_TYPE_TAP,
  59 };
  60
  61 int device_fd = -1;
  62 int device_type;
  63 char *device;
  64 char *interface;
  65 char ifrname[IFNAMSIZ];
  66 char *device_info;
  67
  68 int device_total_in = 0;
  69 int device_total_out = 0;
  70
  71 /*
  72   open the local ethertap device
  73 */
  74 int setup_device(void)
  75 {
  76         struct ifreq ifr;
  77
  78         cp();
  79
  80         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  81                 device = DEFAULT_DEVICE;
  82
  83         if(!get_config_string(lookup_config(config_tree, "Interface"), &interface))
  84 #ifdef HAVE_TUNTAP
  85                 interface = netname;
  86 #else
  87                 interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
  88 #endif
  89         device_fd = open(device, O_RDWR | O_NONBLOCK);
  90
  91         if(device_fd < 0) {
  92                 syslog(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
  93                 return -1;
  94         }
  95
  96 #ifdef HAVE_TUNTAP
  97         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
  98
  99         memset(&ifr, 0, sizeof(ifr));
 100         if(routing_mode == RMODE_ROUTER) {
 101                 ifr.ifr_flags = IFF_TUN;
 102                 device_type = DEVICE_TYPE_TUN;
 103                 device_info = _("Linux tun/tap device (tun mode)");
 104         } else {
 105                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 106                 device_type = DEVICE_TYPE_TAP;
 107                 device_info = _("Linux tun/tap device (tap mode)");
 108         }
 109
 110         if(interface)
 111                 strncpy(ifr.ifr_name, interface, IFNAMSIZ);
 112
 113         if(!ioctl(device_fd, TUNSETIFF, (void *) &ifr)) {
 114                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 115                 interface = ifrname;
 116         } else if(!ioctl(device_fd, (('T' << 8) | 202), (void *) &ifr)) {
 117                 syslog(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
 118                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
 119                 interface = ifrname;
 120         } else
 121 #endif
 122         {
 123                 if(routing_mode == RMODE_ROUTER)
 124                         overwrite_mac = 1;
 125                 device_info = _("Linux ethertap device");
 126                 device_type = DEVICE_TYPE_ETHERTAP;
 127                 interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
 128         }
 129
 130         syslog(LOG_INFO, _("%s is a %s"), device, device_info);
 131
 132         return 0;
 133 }
 134
 135 void close_device(void)
 136 {
 137         cp();
 138
 139         close(device_fd);
 140 }
 141
 142 /*
 143   read, encrypt and send data that is
 144   available through the ethertap device
 145 */
 146 int read_packet(vpn_packet_t *packet)
 147 {
 148         int lenin;
 149
 150         cp();
 151
 152         switch(device_type) {
 153                 case DEVICE_TYPE_TUN:
 154                         lenin = read(device_fd, packet->data + 10, MTU - 10);
 155
 156                         if(lenin <= 0) {
 157                                 syslog(LOG_ERR, _("Error while reading from %s %s: %s"),
 158                                            device_info, device, strerror(errno));
 159                                 return -1;
 160                         }
 161
 162                         packet->len = lenin + 10;
 163                         break;
 164                 case DEVICE_TYPE_TAP:
 165                         lenin = read(device_fd, packet->data, MTU);
 166
 167                         if(lenin <= 0) {
 168                                 syslog(LOG_ERR, _("Error while reading from %s %s: %s"),
 169                                            device_info, device, strerror(errno));
 170                                 return -1;
 171                         }
 172
 173                         packet->len = lenin;
 174                         break;
 175                 case DEVICE_TYPE_ETHERTAP:
 176                         lenin = read(device_fd, packet->data - 2, MTU + 2);
 177
 178                         if(lenin <= 0) {
 179                                 syslog(LOG_ERR, _("Error while reading from %s %s: %s"),
 180                                            device_info, device, strerror(errno));
 181                                 return -1;
 182                         }
 183
 184                         packet->len = lenin - 2;
 185                         break;
 186         }
 187
 188         device_total_in += packet->len;
 189
 190         if(debug_lvl >= DEBUG_TRAFFIC) {
 191                 syslog(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
 192                            device_info);
 193         }
 194
 195         return 0;
 196 }
 197
 198 int write_packet(vpn_packet_t *packet)
 199 {
 200         cp();
 201
 202         if(debug_lvl >= DEBUG_TRAFFIC)
 203                 syslog(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
 204                            packet->len, device_info);
 205
 206         switch(device_type) {
 207                 case DEVICE_TYPE_TUN:
 208                         packet->data[10] = packet->data[11] = 0;
 209                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
 210                                 syslog(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 211                                            strerror(errno));
 212                                 return -1;
 213                         }
 214                         break;
 215                 case DEVICE_TYPE_TAP:
 216                         if(write(device_fd, packet->data, packet->len) < 0) {
 217                                 syslog(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 218                                            strerror(errno));
 219                                 return -1;
 220                         }
 221                         break;
 222                 case DEVICE_TYPE_ETHERTAP:
 223                         *(short int *)(packet->data - 2) = packet->len;
 224
 225                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
 226                                 syslog(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
 227                                            strerror(errno));
 228                                 return -1;
 229                         }
 230                         break;
 231         }
 232
 233         device_total_out += packet->len;
 234
 235         return 0;
 236 }
 237
 238 void dump_device_stats(void)
 239 {
 240         cp();
 241
 242         syslog(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
 243         syslog(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
 244         syslog(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
 245 }