tinc-vpn.org Git - tinc/blob - src/cygwin/device.c

   1 /*
   2     device.c -- Interaction with Windows tap driver in a Cygwin environment
   3     Copyright (C) 2002-2005 Ivo Timmermans,
   4                   2002-2011 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 <w32api/windows.h>
  24 #include <w32api/winioctl.h>
  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
  34 #include "mingw/common.h"
  35
  36 int device_fd = -1;
  37 static HANDLE device_handle = INVALID_HANDLE_VALUE;
  38 char *device = NULL;
  39 char *iface = NULL;
  40 static char *device_info = NULL;
  41
  42 static uint64_t device_total_in = 0;
  43 static uint64_t device_total_out = 0;
  44
  45 static pid_t reader_pid;
  46 static int sp[2];
  47
  48 static bool setup_device(void) {
  49         HKEY key, key2;
  50         int i, err;
  51
  52         char regpath[1024];
  53         char adapterid[1024];
  54         char adaptername[1024];
  55         char tapname[1024];
  56         char gelukt = 0;
  57         long len;
  58
  59         bool found = false;
  60
  61         get_config_string(lookup_config(config_tree, "Device"), &device);
  62         get_config_string(lookup_config(config_tree, "Interface"), &iface);
  63
  64         /* Open registry and look for network adapters */
  65
  66         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
  67                 logger(LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
  68                 return false;
  69         }
  70
  71         for (i = 0; ; i++) {
  72                 len = sizeof(adapterid);
  73                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL))
  74                         break;
  75
  76                 /* Find out more about this adapter */
  77
  78                 snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
  79
  80                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2))
  81                         continue;
  82
  83                 len = sizeof(adaptername);
  84                 err = RegQueryValueEx(key2, "Name", 0, 0, adaptername, &len);
  85
  86                 RegCloseKey(key2);
  87
  88                 if(err)
  89                         continue;
  90
  91                 if(device) {
  92                         if(!strcmp(device, adapterid)) {
  93                                 found = true;
  94                                 break;
  95                         } else
  96                                 continue;
  97                 }
  98
  99                 if(iface) {
 100                         if(!strcmp(iface, adaptername)) {
 101                                 found = true;
 102                                 break;
 103                         } else
 104                                 continue;
 105                 }
 106
 107                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 108                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 109                 if(device_handle != INVALID_HANDLE_VALUE) {
 110                         CloseHandle(device_handle);
 111                         found = true;
 112                         break;
 113                 }
 114         }
 115
 116         RegCloseKey(key);
 117
 118         if(!found) {
 119                 logger(LOG_ERR, "No Windows tap device found!");
 120                 return false;
 121         }
 122
 123         if(!device)
 124                 device = xstrdup(adapterid);
 125
 126         if(!iface)
 127                 iface = xstrdup(adaptername);
 128
 129         snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 130
 131         /* Now we are going to open this device twice: once for reading and once for writing.
 132            We do this because apparently it isn't possible to check for activity in the select() loop.
 133            Furthermore I don't really know how to do it the "Windows" way. */
 134
 135         if(socketpair(AF_UNIX, SOCK_DGRAM, PF_UNIX, sp)) {
 136                 logger(LOG_DEBUG, "System call `%s' failed: %s", "socketpair", strerror(errno));
 137                 return false;
 138         }
 139
 140         /* The parent opens the tap device for writing. */
 141
 142         device_handle = CreateFile(tapname, GENERIC_WRITE,  FILE_SHARE_READ,  0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM , 0);
 143
 144         if(device_handle == INVALID_HANDLE_VALUE) {
 145                 logger(LOG_ERR, "Could not open Windows tap device %s (%s) for writing: %s", device, iface, winerror(GetLastError()));
 146                 return false;
 147         }
 148
 149         device_fd = sp[0];
 150
 151         /* Get MAC address from tap device */
 152
 153         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof(mymac.x), &len, 0)) {
 154                 logger(LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 155                 return false;
 156         }
 157
 158         if(routing_mode == RMODE_ROUTER) {
 159                 overwrite_mac = 1;
 160         }
 161
 162         /* Now we start the child */
 163
 164         reader_pid = fork();
 165
 166         if(reader_pid == -1) {
 167                 logger(LOG_DEBUG, "System call `%s' failed: %s", "fork", strerror(errno));
 168                 return false;
 169         }
 170
 171         if(!reader_pid) {
 172                 /* The child opens the tap device for reading, blocking.
 173                    It passes everything it reads to the socket. */
 174
 175                 char buf[MTU];
 176                 long lenin;
 177
 178                 CloseHandle(device_handle);
 179
 180                 device_handle = CreateFile(tapname, GENERIC_READ, FILE_SHARE_WRITE, 0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 181
 182                 if(device_handle == INVALID_HANDLE_VALUE) {
 183                         logger(LOG_ERR, "Could not open Windows tap device %s (%s) for reading: %s", device, iface, winerror(GetLastError()));
 184                         buf[0] = 0;
 185                         write(sp[1], buf, 1);
 186                         exit(1);
 187                 }
 188
 189                 logger(LOG_DEBUG, "Tap reader forked and running.");
 190
 191                 /* Notify success */
 192
 193                 buf[0] = 1;
 194                 write(sp[1], buf, 1);
 195
 196                 /* Pass packets */
 197
 198                 for(;;) {
 199                         ReadFile(device_handle, buf, MTU, &lenin, NULL);
 200                         write(sp[1], buf, lenin);
 201                 }
 202         }
 203
 204         read(device_fd, &gelukt, 1);
 205         if(gelukt != 1) {
 206                 logger(LOG_DEBUG, "Tap reader failed!");
 207                 return false;
 208         }
 209
 210         device_info = "Windows tap device";
 211
 212         logger(LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 213
 214         return true;
 215 }
 216
 217 static void close_device(void) {
 218         close(sp[0]);
 219         close(sp[1]);
 220         CloseHandle(device_handle);
 221
 222         kill(reader_pid, SIGKILL);
 223
 224         free(device);
 225         free(iface);
 226 }
 227
 228 static bool read_packet(vpn_packet_t *packet) {
 229         int lenin;
 230
 231         if((lenin = read(sp[0], packet->data, MTU)) <= 0) {
 232                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 233                            device, strerror(errno));
 234                 return false;
 235         }
 236
 237         packet->len = lenin;
 238
 239         device_total_in += packet->len;
 240
 241         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 242                            device_info);
 243
 244         return true;
 245 }
 246
 247 static bool write_packet(vpn_packet_t *packet) {
 248         long lenout;
 249
 250         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 251                            packet->len, device_info);
 252
 253         if(!WriteFile (device_handle, packet->data, packet->len, &lenout, NULL)) {
 254                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
 255                 return false;
 256         }
 257
 258         device_total_out += packet->len;
 259
 260         return true;
 261 }
 262
 263 static void dump_device_stats(void) {
 264         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 265         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 266         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 267 }
 268
 269 const devops_t os_devops = {
 270         .setup = setup_device,
 271         .close = close_device,
 272         .read = read_packet,
 273         .write = write_packet,
 274         .dump_stats = dump_device_stats,
 275 };