www.tinc-vpn.org Git - tinc/blob - src/mingw/device.c

   1 /*
   2     device.c -- Interaction with Windows tap driver in a MinGW environment
   3     Copyright (C) 2002-2005 Ivo Timmermans,
   4                   2002-2016 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 <windows.h>
  24 #include <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 "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 const char *device_info = "Windows tap device";
  41
  42 static uint64_t device_total_in = 0;
  43 static uint64_t device_total_out = 0;
  44
  45 extern char *myport;
  46 OVERLAPPED r_overlapped;
  47 OVERLAPPED w_overlapped;
  48
  49 static DWORD WINAPI tapreader(void *bla) {
  50         int status;
  51         DWORD len;
  52         vpn_packet_t packet;
  53         int errors = 0;
  54
  55         logger(LOG_DEBUG, "Tap reader running");
  56
  57         /* Read from tap device and send to parent */
  58
  59         r_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
  60
  61         for(;;) {
  62                 ResetEvent(r_overlapped.hEvent);
  63
  64                 status = ReadFile(device_handle, packet.data, MTU, &len, &r_overlapped);
  65
  66                 if(!status) {
  67                         if(GetLastError() == ERROR_IO_PENDING) {
  68                                 WaitForSingleObject(r_overlapped.hEvent, INFINITE);
  69
  70                                 if(!GetOverlappedResult(device_handle, &r_overlapped, &len, FALSE)) {
  71                                         continue;
  72                                 }
  73                         } else {
  74                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
  75                                        device, strerror(errno));
  76                                 errors++;
  77
  78                                 if(errors >= 10) {
  79                                         EnterCriticalSection(&mutex);
  80                                         running = false;
  81                                         LeaveCriticalSection(&mutex);
  82                                 }
  83
  84                                 usleep(1000000);
  85                                 continue;
  86                         }
  87                 }
  88
  89                 errors = 0;
  90                 packet.len = len;
  91                 packet.priority = 0;
  92
  93                 EnterCriticalSection(&mutex);
  94                 route(myself, &packet);
  95                 LeaveCriticalSection(&mutex);
  96         }
  97
  98         return 0;
  99 }
 100
 101 static bool setup_device(void) {
 102         HKEY key, key2;
 103         int i;
 104
 105         char regpath[1024];
 106         char adapterid[1024];
 107         char adaptername[1024];
 108         char tapname[1024];
 109         DWORD len;
 110         unsigned long status;
 111
 112         bool found = false;
 113
 114         int err;
 115         HANDLE thread;
 116
 117         get_config_string(lookup_config(config_tree, "Device"), &device);
 118         get_config_string(lookup_config(config_tree, "Interface"), &iface);
 119
 120         if(device && iface) {
 121                 logger(LOG_WARNING, "Warning: both Device and Interface specified, results may not be as expected");
 122         }
 123
 124         /* Open registry and look for network adapters */
 125
 126         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
 127                 logger(LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
 128                 return false;
 129         }
 130
 131         for(i = 0; ; i++) {
 132                 len = sizeof(adapterid);
 133
 134                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL)) {
 135                         break;
 136                 }
 137
 138                 /* Find out more about this adapter */
 139
 140                 snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
 141
 142                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2)) {
 143                         continue;
 144                 }
 145
 146                 len = sizeof(adaptername);
 147                 err = RegQueryValueEx(key2, "Name", 0, 0, (LPBYTE)adaptername, &len);
 148
 149                 RegCloseKey(key2);
 150
 151                 if(err) {
 152                         continue;
 153                 }
 154
 155                 if(device) {
 156                         if(!strcmp(device, adapterid)) {
 157                                 found = true;
 158                                 break;
 159                         } else {
 160                                 continue;
 161                         }
 162                 }
 163
 164                 if(iface) {
 165                         if(!strcmp(iface, adaptername)) {
 166                                 found = true;
 167                                 break;
 168                         } else {
 169                                 continue;
 170                         }
 171                 }
 172
 173                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 174                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, 0);
 175
 176                 if(device_handle != INVALID_HANDLE_VALUE) {
 177                         found = true;
 178                         break;
 179                 }
 180         }
 181
 182         RegCloseKey(key);
 183
 184         if(!found) {
 185                 logger(LOG_ERR, "No Windows tap device found!");
 186                 return false;
 187         }
 188
 189         if(!device) {
 190                 device = xstrdup(adapterid);
 191         }
 192
 193         if(!iface) {
 194                 iface = xstrdup(adaptername);
 195         }
 196
 197         /* Try to open the corresponding tap device */
 198
 199         if(device_handle == INVALID_HANDLE_VALUE) {
 200                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 201                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, 0);
 202         }
 203
 204         if(device_handle == INVALID_HANDLE_VALUE) {
 205                 logger(LOG_ERR, "%s (%s) is not a usable Windows tap device: %s", device, iface, winerror(GetLastError()));
 206                 return false;
 207         }
 208
 209         /* Get MAC address from tap device */
 210
 211         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof(mymac.x), &len, 0)) {
 212                 logger(LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 213                 return false;
 214         }
 215
 216         if(routing_mode == RMODE_ROUTER) {
 217                 overwrite_mac = 1;
 218         }
 219
 220         /* Create overlapped events for tap I/O */
 221
 222         r_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
 223         w_overlapped.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 224
 225         /* Start the tap reader */
 226
 227         thread = CreateThread(NULL, 0, tapreader, NULL, 0, NULL);
 228
 229         if(!thread) {
 230                 logger(LOG_ERR, "System call `%s' failed: %s", "CreateThread", winerror(GetLastError()));
 231                 return false;
 232         }
 233
 234         /* Set media status for newer TAP-Win32 devices */
 235
 236         status = true;
 237         DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof(status), &status, sizeof(status), &len, NULL);
 238
 239         logger(LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 240
 241         return true;
 242 }
 243
 244 static void close_device(void) {
 245         CloseHandle(device_handle);
 246
 247         free(device);
 248         free(iface);
 249 }
 250
 251 static bool read_packet(vpn_packet_t *packet) {
 252         return false;
 253 }
 254
 255 static bool write_packet(vpn_packet_t *packet) {
 256         DWORD lenout;
 257         static vpn_packet_t queue;
 258
 259         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 260                                 packet->len, device_info);
 261
 262         /* Check if there is something in progress */
 263
 264         if(queue.len) {
 265                 DWORD size;
 266                 BOOL success = GetOverlappedResult(device_handle, &w_overlapped, &size, FALSE);
 267
 268                 if(success) {
 269                         ResetEvent(&w_overlapped);
 270                         queue.len = 0;
 271                 } else {
 272                         int err = GetLastError();
 273
 274                         if(err != ERROR_IO_INCOMPLETE) {
 275                                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error completing previously queued write: %s", winerror(err));
 276                                 ResetEvent(&w_overlapped);
 277                                 queue.len = 0;
 278                         } else {
 279                                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Previous overlapped write still in progress");
 280                                 // drop this packet
 281                                 return true;
 282                         }
 283                 }
 284         }
 285
 286         /* Otherwise, try to write. */
 287
 288         memcpy(queue.data, packet->data, packet->len);
 289
 290         if(!WriteFile(device_handle, queue.data, packet->len, &lenout, &w_overlapped)) {
 291                 int err = GetLastError();
 292
 293                 if(err != ERROR_IO_PENDING) {
 294                         logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(err));
 295                         return false;
 296                 }
 297
 298                 // Write is being done asynchronously.
 299                 queue.len = packet->len;
 300         } else {
 301                 // Write was completed immediately.
 302                 ResetEvent(&w_overlapped);
 303         }
 304
 305         device_total_out += packet->len;
 306
 307         return true;
 308 }
 309
 310 static void dump_device_stats(void) {
 311         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 312         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 313         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 314 }
 315
 316 const devops_t os_devops = {
 317         .setup = setup_device,
 318         .close = close_device,
 319         .read = read_packet,
 320         .write = write_packet,
 321         .dump_stats = dump_device_stats,
 322 };