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         if(device && interface)
 117                 logger(LOG_WARNING, "Warning: both Device and Interface specified, results may not be as expected");
 118
 119         /* Open registry and look for network adapters */
 120
 121         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
 122                 logger(LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
 123                 return false;
 124         }
 125
 126         for (i = 0; ; i++) {
 127                 len = sizeof(adapterid);
 128                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL))
 129                         break;
 130
 131                 /* Find out more about this adapter */
 132
 133                 snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
 134
 135                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2))
 136                         continue;
 137
 138                 len = sizeof(adaptername);
 139                 err = RegQueryValueEx(key2, "Name", 0, 0, (LPBYTE)adaptername, &len);
 140
 141                 RegCloseKey(key2);
 142
 143                 if(err)
 144                         continue;
 145
 146                 if(device) {
 147                         if(!strcmp(device, adapterid)) {
 148                                 found = true;
 149                                 break;
 150                         } else
 151                                 continue;
 152                 }
 153
 154                 if(iface) {
 155                         if(!strcmp(iface, adaptername)) {
 156                                 found = true;
 157                                 break;
 158                         } else
 159                                 continue;
 160                 }
 161
 162                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 163                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, 0);
 164                 if(device_handle != INVALID_HANDLE_VALUE) {
 165                         found = true;
 166                         break;
 167                 }
 168         }
 169
 170         RegCloseKey(key);
 171
 172         if(!found) {
 173                 logger(LOG_ERR, "No Windows tap device found!");
 174                 return false;
 175         }
 176
 177         if(!device)
 178                 device = xstrdup(adapterid);
 179
 180         if(!iface)
 181                 iface = xstrdup(adaptername);
 182
 183         /* Try to open the corresponding tap device */
 184
 185         if(device_handle == INVALID_HANDLE_VALUE) {
 186                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 187                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, 0);
 188         }
 189
 190         if(device_handle == INVALID_HANDLE_VALUE) {
 191                 logger(LOG_ERR, "%s (%s) is not a usable Windows tap device: %s", device, iface, winerror(GetLastError()));
 192                 return false;
 193         }
 194
 195         /* Get MAC address from tap device */
 196
 197         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof(mymac.x), &len, 0)) {
 198                 logger(LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 199                 return false;
 200         }
 201
 202         if(routing_mode == RMODE_ROUTER) {
 203                 overwrite_mac = 1;
 204         }
 205
 206         /* Create overlapped events for tap I/O */
 207
 208         r_overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
 209         w_overlapped.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 210
 211         /* Start the tap reader */
 212
 213         thread = CreateThread(NULL, 0, tapreader, NULL, 0, NULL);
 214
 215         if(!thread) {
 216                 logger(LOG_ERR, "System call `%s' failed: %s", "CreateThread", winerror(GetLastError()));
 217                 return false;
 218         }
 219
 220         /* Set media status for newer TAP-Win32 devices */
 221
 222         status = true;
 223         DeviceIoControl(device_handle, TAP_IOCTL_SET_MEDIA_STATUS, &status, sizeof(status), &status, sizeof(status), &len, NULL);
 224
 225         device_info = "Windows tap device";
 226
 227         logger(LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 228
 229         return true;
 230 }
 231
 232 static void close_device(void) {
 233         CloseHandle(device_handle);
 234
 235         free(device);
 236         free(iface);
 237 }
 238
 239 static bool read_packet(vpn_packet_t *packet) {
 240         return false;
 241 }
 242
 243 static bool write_packet(vpn_packet_t *packet) {
 244         DWORD lenout;
 245         static vpn_packet_t queue;
 246
 247         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 248                            packet->len, device_info);
 249
 250         /* Check if there is something in progress */
 251
 252         if(queue.len) {
 253                 DWORD size;
 254                 BOOL success = GetOverlappedResult(device_handle, &w_overlapped, &size, FALSE);
 255                 if(success) {
 256                         ResetEvent(&w_overlapped);
 257                         queue.len = 0;
 258                 } else {
 259                         int err = GetLastError();
 260                         if(err != ERROR_IO_INCOMPLETE) {
 261                                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error completing previously queued write: %s", winerror(err));
 262                                 ResetEvent(&w_overlapped);
 263                                 queue.len = 0;
 264                         } else {
 265                                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Previous overlapped write still in progress");
 266                                 // drop this packet
 267                                 return true;
 268                         }
 269                 }
 270         }
 271
 272         /* Otherwise, try to write. */
 273
 274         memcpy(queue.data, packet->data, packet->len);
 275
 276         if(!WriteFile(device_handle, queue.data, packet->len, &lenout, &w_overlapped)) {
 277                 int err = GetLastError();
 278                 if(err != ERROR_IO_PENDING) {
 279                         logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(err));
 280                         return false;
 281                 }
 282                 // Write is being done asynchronously.
 283                 queue.len = packet->len;
 284         } else {
 285                 // Write was completed immediately.
 286                 ResetEvent(&w_overlapped);
 287         }
 288
 289         device_total_out += packet->len;
 290
 291         return true;
 292 }
 293
 294 static void dump_device_stats(void) {
 295         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 296         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 297         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 298 }
 299
 300 const devops_t os_devops = {
 301         .setup = setup_device,
 302         .close = close_device,
 303         .read = read_packet,
 304         .write = write_packet,
 305         .dump_stats = dump_device_stats,
 306 };