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                   2002-2014 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 char *device_info = NULL;
  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                                 if(!GetOverlappedResult(device_handle, &r_overlapped, &len, FALSE))
  70                                         continue;
  71                         } else {
  72                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
  73                                            device, strerror(errno));
  74                                 errors++;
  75                                 if(errors >= 10) {
  76                                         EnterCriticalSection(&mutex);
  77                                         running = false;
  78                                         LeaveCriticalSection(&mutex);
  79                                 }
  80                                 usleep(1000000);
  81                                 continue;
  82                         }
  83                 }
  84
  85                 errors = 0;
  86                 packet.len = len;
  87                 packet.priority = 0;
  88
  89                 EnterCriticalSection(&mutex);
  90                 route(myself, &packet);
  91                 LeaveCriticalSection(&mutex);
  92         }
  93
  94         return 0;
  95 }
  96
  97 static bool setup_device(void) {
  98         HKEY key, key2;
  99         int i;
 100
 101         char regpath[1024];
 102         char adapterid[1024];
 103         char adaptername[1024];
 104         char tapname[1024];
 105         DWORD len;
 106         unsigned long status;
 107
 108         bool found = false;
 109
 110         int err;
 111         HANDLE thread;
 112
 113         get_config_string(lookup_config(config_tree, "Device"), &device);
 114         get_config_string(lookup_config(config_tree, "Interface"), &iface);
 115
 116         /* Open registry and look for network adapters */
 117
 118         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
 119                 logger(LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
 120                 return false;
 121         }
 122
 123         for (i = 0; ; i++) {
 124                 len = sizeof(adapterid);
 125                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL))
 126                         break;
 127
 128                 /* Find out more about this adapter */
 129
 130                 snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
 131
 132                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2))
 133                         continue;
 134
 135                 len = sizeof(adaptername);
 136                 err = RegQueryValueEx(key2, "Name", 0, 0, (LPBYTE)adaptername, &len);
 137
 138                 RegCloseKey(key2);
 139
 140                 if(err)
 141                         continue;
 142
 143                 if(device) {
 144                         if(!strcmp(device, adapterid)) {
 145                                 found = true;
 146                                 break;
 147                         } else
 148                                 continue;
 149                 }
 150
 151                 if(iface) {
 152                         if(!strcmp(iface, adaptername)) {
 153                                 found = true;
 154                                 break;
 155                         } else
 156                                 continue;
 157                 }
 158
 159                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 160                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, 0);
 161                 if(device_handle != INVALID_HANDLE_VALUE) {
 162                         found = true;
 163                         break;
 164                 }
 165         }
 166
 167         RegCloseKey(key);
 168
 169         if(!found) {
 170                 logger(LOG_ERR, "No Windows tap device found!");
 171                 return false;
 172         }
 173
 174         if(!device)
 175                 device = xstrdup(adapterid);
 176
 177         if(!iface)
 178                 iface = xstrdup(adaptername);
 179
 180         /* Try to open the corresponding tap device */
 181
 182         if(device_handle == INVALID_HANDLE_VALUE) {
 183                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 184                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, 0);
 185         }
 186
 187         if(device_handle == INVALID_HANDLE_VALUE) {
 188                 logger(LOG_ERR, "%s (%s) is not a usable Windows tap device: %s", device, iface, winerror(GetLastError()));
 189                 return false;
 190         }
 191
 192         /* Get MAC address from tap device */
 193
 194         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof(mymac.x), &len, 0)) {
 195                 logger(LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 196                 return false;
 197         }
 198
 199         if(routing_mode == RMODE_ROUTER) {
 200                 overwrite_mac = 1;
 201         }
 202
 203         /* Create overlapped events for tap I/O */
 204
 205         r_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
 206         w_overlapped.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 207
 208         /* Start the tap reader */
 209
 210         thread = CreateThread(NULL, 0, tapreader, NULL, 0, NULL);
 211
 212         if(!thread) {
 213                 logger(LOG_ERR, "System call `%s' failed: %s", "CreateThread", winerror(GetLastError()));
 214                 return false;
 215         }
 216
 217         /* Set media status for newer TAP-Win32 devices */
 218
 219         status = true;
 220         DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof(status), &status, sizeof(status), &len, NULL);
 221
 222         device_info = "Windows tap device";
 223
 224         logger(LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 225
 226         return true;
 227 }
 228
 229 static void close_device(void) {
 230         CloseHandle(device_handle);
 231
 232         free(device);
 233         free(iface);
 234 }
 235
 236 static bool read_packet(vpn_packet_t *packet) {
 237         return false;
 238 }
 239
 240 static bool write_packet(vpn_packet_t *packet) {
 241         DWORD lenout;
 242         static vpn_packet_t queue;
 243
 244         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 245                            packet->len, device_info);
 246
 247         /* Check if there is something in progress */
 248
 249         if(queue.len) {
 250                 DWORD size;
 251                 BOOL success = GetOverlappedResult(device_handle, &w_overlapped, &size, FALSE);
 252                 if(success) {
 253                         ResetEvent(&w_overlapped);
 254                         queue.len = 0;
 255                 } else {
 256                         int err = GetLastError();
 257                         if(err != ERROR_IO_INCOMPLETE) {
 258                                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error completing previously queued write: %s", winerror(err));
 259                                 ResetEvent(&w_overlapped);
 260                                 queue.len = 0;
 261                         } else {
 262                                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Previous overlapped write still in progress");
 263                                 // drop this packet
 264                                 return true;
 265                         }
 266                 }
 267         }
 268
 269         /* Otherwise, try to write. */
 270
 271         memcpy(queue.data, packet->data, packet->len);
 272
 273         if(!WriteFile(device_handle, queue.data, packet->len, &lenout, &w_overlapped)) {
 274                 int err = GetLastError();
 275                 if(err != ERROR_IO_PENDING) {
 276                         logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(err));
 277                         return false;
 278                 }
 279                 // Write is being done asynchronously.
 280                 queue.len = packet->len;
 281         } else {
 282                 // Write was completed immediately.
 283                 ResetEvent(&w_overlapped);
 284         }
 285
 286         device_total_out += packet->len;
 287
 288         return true;
 289 }
 290
 291 static void dump_device_stats(void) {
 292         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 293         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 294         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 295 }
 296
 297 const devops_t os_devops = {
 298         .setup = setup_device,
 299         .close = close_device,
 300         .read = read_packet,
 301         .write = write_packet,
 302         .dump_stats = dump_device_stats,
 303 };