net/tap-win32.c

   1 /*
   2  *  TAP-Win32 -- A kernel driver to provide virtual tap device functionality
   3  *               on Windows.  Originally derived from the CIPE-Win32
   4  *               project by Damion K. Wilson, with extensive modifications by
   5  *               James Yonan.
   6  *
   7  *  All source code which derives from the CIPE-Win32 project is
   8  *  Copyright (C) Damion K. Wilson, 2003, and is released under the
   9  *  GPL version 2 (see below).
  10  *
  11  *  All other source code is Copyright (C) James Yonan, 2003-2004,
  12  *  and is released under the GPL version 2 (see below).
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2 of the License, or
  17  *  (at your option) any later version.
  18  *
  19  *  This program is distributed in the hope that it will be useful,
  20  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  *  GNU General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License
  25  *  along with this program (see the file COPYING included with this
  26  *  distribution); if not, see <http://www.gnu.org/licenses/>.
  27  */
  28
  29 #include "qemu/osdep.h"
  30 #include "tap_int.h"
  31
  32 #include "qemu-common.h"
  33 #include "clients.h"            /* net_init_tap */
  34 #include "net/net.h"
  35 #include "net/tap.h"            /* tap_has_ufo, ... */
  36 #include "sysemu/sysemu.h"
  37 #include "qemu/error-report.h"
  38 #include <windows.h>
  39 #include <winioctl.h>
  40
  41 //=============
  42 // TAP IOCTLs
  43 //=============
  44
  45 #define TAP_CONTROL_CODE(request,method) \
  46   CTL_CODE (FILE_DEVICE_UNKNOWN, request, method, FILE_ANY_ACCESS)
  47
  48 #define TAP_IOCTL_GET_MAC               TAP_CONTROL_CODE (1, METHOD_BUFFERED)
  49 #define TAP_IOCTL_GET_VERSION           TAP_CONTROL_CODE (2, METHOD_BUFFERED)
  50 #define TAP_IOCTL_GET_MTU               TAP_CONTROL_CODE (3, METHOD_BUFFERED)
  51 #define TAP_IOCTL_GET_INFO              TAP_CONTROL_CODE (4, METHOD_BUFFERED)
  52 #define TAP_IOCTL_CONFIG_POINT_TO_POINT TAP_CONTROL_CODE (5, METHOD_BUFFERED)
  53 #define TAP_IOCTL_SET_MEDIA_STATUS      TAP_CONTROL_CODE (6, METHOD_BUFFERED)
  54 #define TAP_IOCTL_CONFIG_DHCP_MASQ      TAP_CONTROL_CODE (7, METHOD_BUFFERED)
  55 #define TAP_IOCTL_GET_LOG_LINE          TAP_CONTROL_CODE (8, METHOD_BUFFERED)
  56 #define TAP_IOCTL_CONFIG_DHCP_SET_OPT   TAP_CONTROL_CODE (9, METHOD_BUFFERED)
  57
  58 //=================
  59 // Registry keys
  60 //=================
  61
  62 #define ADAPTER_KEY "SYSTEM\\CurrentControlSet\\Control\\Class\\{4D36E972-E325-11CE-BFC1-08002BE10318}"
  63
  64 #define NETWORK_CONNECTIONS_KEY "SYSTEM\\CurrentControlSet\\Control\\Network\\{4D36E972-E325-11CE-BFC1-08002BE10318}"
  65
  66 //======================
  67 // Filesystem prefixes
  68 //======================
  69
  70 #define USERMODEDEVICEDIR "\\\\.\\Global\\"
  71 #define TAPSUFFIX         ".tap"
  72
  73
  74 //======================
  75 // Compile time configuration
  76 //======================
  77
  78 //#define DEBUG_TAP_WIN32
  79
  80 /* FIXME: The asynch write path appears to be broken at
  81  * present. WriteFile() ignores the lpNumberOfBytesWritten parameter
  82  * for overlapped writes, with the result we return zero bytes sent,
  83  * and after handling a single packet, receive is disabled for this
  84  * interface. */
  85 /* #define TUN_ASYNCHRONOUS_WRITES 1 */
  86
  87 #define TUN_BUFFER_SIZE 1560
  88 #define TUN_MAX_BUFFER_COUNT 32
  89
  90 /*
  91  * The data member "buffer" must be the first element in the tun_buffer
  92  * structure. See the function, tap_win32_free_buffer.
  93  */
  94 typedef struct tun_buffer_s {
  95     unsigned char buffer [TUN_BUFFER_SIZE];
  96     unsigned long read_size;
  97     struct tun_buffer_s* next;
  98 } tun_buffer_t;
  99
 100 typedef struct tap_win32_overlapped {
 101     HANDLE handle;
 102     HANDLE read_event;
 103     HANDLE write_event;
 104     HANDLE output_queue_semaphore;
 105     HANDLE free_list_semaphore;
 106     HANDLE tap_semaphore;
 107     CRITICAL_SECTION output_queue_cs;
 108     CRITICAL_SECTION free_list_cs;
 109     OVERLAPPED read_overlapped;
 110     OVERLAPPED write_overlapped;
 111     tun_buffer_t buffers[TUN_MAX_BUFFER_COUNT];
 112     tun_buffer_t* free_list;
 113     tun_buffer_t* output_queue_front;
 114     tun_buffer_t* output_queue_back;
 115 } tap_win32_overlapped_t;
 116
 117 static tap_win32_overlapped_t tap_overlapped;
 118
 119 static tun_buffer_t* get_buffer_from_free_list(tap_win32_overlapped_t* const overlapped)
 120 {
 121     tun_buffer_t* buffer = NULL;
 122     WaitForSingleObject(overlapped->free_list_semaphore, INFINITE);
 123     EnterCriticalSection(&overlapped->free_list_cs);
 124     buffer = overlapped->free_list;
 125 //    assert(buffer != NULL);
 126     overlapped->free_list = buffer->next;
 127     LeaveCriticalSection(&overlapped->free_list_cs);
 128     buffer->next = NULL;
 129     return buffer;
 130 }
 131
 132 static void put_buffer_on_free_list(tap_win32_overlapped_t* const overlapped, tun_buffer_t* const buffer)
 133 {
 134     EnterCriticalSection(&overlapped->free_list_cs);
 135     buffer->next = overlapped->free_list;
 136     overlapped->free_list = buffer;
 137     LeaveCriticalSection(&overlapped->free_list_cs);
 138     ReleaseSemaphore(overlapped->free_list_semaphore, 1, NULL);
 139 }
 140
 141 static tun_buffer_t* get_buffer_from_output_queue(tap_win32_overlapped_t* const overlapped, const int block)
 142 {
 143     tun_buffer_t* buffer = NULL;
 144     DWORD result, timeout = block ? INFINITE : 0L;
 145
 146     // Non-blocking call
 147     result = WaitForSingleObject(overlapped->output_queue_semaphore, timeout);
 148
 149     switch (result)
 150     {
 151         // The semaphore object was signaled.
 152         case WAIT_OBJECT_0:
 153             EnterCriticalSection(&overlapped->output_queue_cs);
 154
 155             buffer = overlapped->output_queue_front;
 156             overlapped->output_queue_front = buffer->next;
 157
 158             if(overlapped->output_queue_front == NULL) {
 159                 overlapped->output_queue_back = NULL;
 160             }
 161
 162             LeaveCriticalSection(&overlapped->output_queue_cs);
 163             break;
 164
 165         // Semaphore was nonsignaled, so a time-out occurred.
 166         case WAIT_TIMEOUT:
 167             // Cannot open another window.
 168             break;
 169     }
 170
 171     return buffer;
 172 }
 173
 174 static tun_buffer_t* get_buffer_from_output_queue_immediate (tap_win32_overlapped_t* const overlapped)
 175 {
 176     return get_buffer_from_output_queue(overlapped, 0);
 177 }
 178
 179 static void put_buffer_on_output_queue(tap_win32_overlapped_t* const overlapped, tun_buffer_t* const buffer)
 180 {
 181     EnterCriticalSection(&overlapped->output_queue_cs);
 182
 183     if(overlapped->output_queue_front == NULL && overlapped->output_queue_back == NULL) {
 184         overlapped->output_queue_front = overlapped->output_queue_back = buffer;
 185     } else {
 186         buffer->next = NULL;
 187         overlapped->output_queue_back->next = buffer;
 188         overlapped->output_queue_back = buffer;
 189     }
 190
 191     LeaveCriticalSection(&overlapped->output_queue_cs);
 192
 193     ReleaseSemaphore(overlapped->output_queue_semaphore, 1, NULL);
 194 }
 195
 196
 197 static int is_tap_win32_dev(const char *guid)
 198 {
 199     HKEY netcard_key;
 200     LONG status;
 201     DWORD len;
 202     int i = 0;
 203
 204     status = RegOpenKeyEx(
 205         HKEY_LOCAL_MACHINE,
 206         ADAPTER_KEY,
 207         0,
 208         KEY_READ,
 209         &netcard_key);
 210
 211     if (status != ERROR_SUCCESS) {
 212         return FALSE;
 213     }
 214
 215     for (;;) {
 216         char enum_name[256];
 217         char unit_string[256];
 218         HKEY unit_key;
 219         char component_id_string[] = "ComponentId";
 220         char component_id[256];
 221         char net_cfg_instance_id_string[] = "NetCfgInstanceId";
 222         char net_cfg_instance_id[256];
 223         DWORD data_type;
 224
 225         len = sizeof (enum_name);
 226         status = RegEnumKeyEx(
 227             netcard_key,
 228             i,
 229             enum_name,
 230             &len,
 231             NULL,
 232             NULL,
 233             NULL,
 234             NULL);
 235
 236         if (status == ERROR_NO_MORE_ITEMS)
 237             break;
 238         else if (status != ERROR_SUCCESS) {
 239             return FALSE;
 240         }
 241
 242         snprintf (unit_string, sizeof(unit_string), "%s\\%s",
 243                   ADAPTER_KEY, enum_name);
 244
 245         status = RegOpenKeyEx(
 246             HKEY_LOCAL_MACHINE,
 247             unit_string,
 248             0,
 249             KEY_READ,
 250             &unit_key);
 251
 252         if (status != ERROR_SUCCESS) {
 253             return FALSE;
 254         } else {
 255             len = sizeof (component_id);
 256             status = RegQueryValueEx(
 257                 unit_key,
 258                 component_id_string,
 259                 NULL,
 260                 &data_type,
 261                 (LPBYTE)component_id,
 262                 &len);
 263
 264             if (!(status != ERROR_SUCCESS || data_type != REG_SZ)) {
 265                 len = sizeof (net_cfg_instance_id);
 266                 status = RegQueryValueEx(
 267                     unit_key,
 268                     net_cfg_instance_id_string,
 269                     NULL,
 270                     &data_type,
 271                     (LPBYTE)net_cfg_instance_id,
 272                     &len);
 273
 274                 if (status == ERROR_SUCCESS && data_type == REG_SZ) {
 275                     if (/* !strcmp (component_id, TAP_COMPONENT_ID) &&*/
 276                         !strcmp (net_cfg_instance_id, guid)) {
 277                         RegCloseKey (unit_key);
 278                         RegCloseKey (netcard_key);
 279                         return TRUE;
 280                     }
 281                 }
 282             }
 283             RegCloseKey (unit_key);
 284         }
 285         ++i;
 286     }
 287
 288     RegCloseKey (netcard_key);
 289     return FALSE;
 290 }
 291
 292 static int get_device_guid(
 293     char *name,
 294     int name_size,
 295     char *actual_name,
 296     int actual_name_size)
 297 {
 298     LONG status;
 299     HKEY control_net_key;
 300     DWORD len;
 301     int i = 0;
 302     int stop = 0;
 303
 304     status = RegOpenKeyEx(
 305         HKEY_LOCAL_MACHINE,
 306         NETWORK_CONNECTIONS_KEY,
 307         0,
 308         KEY_READ,
 309         &control_net_key);
 310
 311     if (status != ERROR_SUCCESS) {
 312         return -1;
 313     }
 314
 315     while (!stop)
 316     {
 317         char enum_name[256];
 318         char connection_string[256];
 319         HKEY connection_key;
 320         char name_data[256];
 321         DWORD name_type;
 322         const char name_string[] = "Name";
 323
 324         len = sizeof (enum_name);
 325         status = RegEnumKeyEx(
 326             control_net_key,
 327             i,
 328             enum_name,
 329             &len,
 330             NULL,
 331             NULL,
 332             NULL,
 333             NULL);
 334
 335         if (status == ERROR_NO_MORE_ITEMS)
 336             break;
 337         else if (status != ERROR_SUCCESS) {
 338             return -1;
 339         }
 340
 341         snprintf(connection_string,
 342              sizeof(connection_string),
 343              "%s\\%s\\Connection",
 344              NETWORK_CONNECTIONS_KEY, enum_name);
 345
 346         status = RegOpenKeyEx(
 347             HKEY_LOCAL_MACHINE,
 348             connection_string,
 349             0,
 350             KEY_READ,
 351             &connection_key);
 352
 353         if (status == ERROR_SUCCESS) {
 354             len = sizeof (name_data);
 355             status = RegQueryValueEx(
 356                 connection_key,
 357                 name_string,
 358                 NULL,
 359                 &name_type,
 360                 (LPBYTE)name_data,
 361                 &len);
 362
 363             if (status != ERROR_SUCCESS || name_type != REG_SZ) {
 364                 ++i;
 365                 continue;
 366             }
 367             else {
 368                 if (is_tap_win32_dev(enum_name)) {
 369                     snprintf(name, name_size, "%s", enum_name);
 370                     if (actual_name) {
 371                         if (strcmp(actual_name, "") != 0) {
 372                             if (strcmp(name_data, actual_name) != 0) {
 373                                 RegCloseKey (connection_key);
 374                                 ++i;
 375                                 continue;
 376                             }
 377                         }
 378                         else {
 379                             snprintf(actual_name, actual_name_size, "%s", name_data);
 380                         }
 381                     }
 382                     stop = 1;
 383                 }
 384             }
 385
 386             RegCloseKey (connection_key);
 387         }
 388         ++i;
 389     }
 390
 391     RegCloseKey (control_net_key);
 392
 393     if (stop == 0)
 394         return -1;
 395
 396     return 0;
 397 }
 398
 399 static int tap_win32_set_status(HANDLE handle, int status)
 400 {
 401     unsigned long len = 0;
 402
 403     return DeviceIoControl(handle, TAP_IOCTL_SET_MEDIA_STATUS,
 404                 &status, sizeof (status),
 405                 &status, sizeof (status), &len, NULL);
 406 }
 407
 408 static void tap_win32_overlapped_init(tap_win32_overlapped_t* const overlapped, const HANDLE handle)
 409 {
 410     overlapped->handle = handle;
 411
 412     overlapped->read_event = CreateEvent(NULL, FALSE, FALSE, NULL);
 413     overlapped->write_event = CreateEvent(NULL, FALSE, FALSE, NULL);
 414
 415     overlapped->read_overlapped.Offset = 0;
 416     overlapped->read_overlapped.OffsetHigh = 0;
 417     overlapped->read_overlapped.hEvent = overlapped->read_event;
 418
 419     overlapped->write_overlapped.Offset = 0;
 420     overlapped->write_overlapped.OffsetHigh = 0;
 421     overlapped->write_overlapped.hEvent = overlapped->write_event;
 422
 423     InitializeCriticalSection(&overlapped->output_queue_cs);
 424     InitializeCriticalSection(&overlapped->free_list_cs);
 425
 426     overlapped->output_queue_semaphore = CreateSemaphore(
 427         NULL,   // default security attributes
 428         0,   // initial count
 429         TUN_MAX_BUFFER_COUNT,   // maximum count
 430         NULL);  // unnamed semaphore
 431
 432     if(!overlapped->output_queue_semaphore)  {
 433         fprintf(stderr, "error creating output queue semaphore!\n");
 434     }
 435
 436     overlapped->free_list_semaphore = CreateSemaphore(
 437         NULL,   // default security attributes
 438         TUN_MAX_BUFFER_COUNT,   // initial count
 439         TUN_MAX_BUFFER_COUNT,   // maximum count
 440         NULL);  // unnamed semaphore
 441
 442     if(!overlapped->free_list_semaphore)  {
 443         fprintf(stderr, "error creating free list semaphore!\n");
 444     }
 445
 446     overlapped->free_list = overlapped->output_queue_front = overlapped->output_queue_back = NULL;
 447
 448     {
 449         unsigned index;
 450         for(index = 0; index < TUN_MAX_BUFFER_COUNT; index++) {
 451             tun_buffer_t* element = &overlapped->buffers[index];
 452             element->next = overlapped->free_list;
 453             overlapped->free_list = element;
 454         }
 455     }
 456     /* To count buffers, initially no-signal. */
 457     overlapped->tap_semaphore = CreateSemaphore(NULL, 0, TUN_MAX_BUFFER_COUNT, NULL);
 458     if(!overlapped->tap_semaphore)
 459         fprintf(stderr, "error creating tap_semaphore.\n");
 460 }
 461
 462 static int tap_win32_write(tap_win32_overlapped_t *overlapped,
 463                            const void *buffer, unsigned long size)
 464 {
 465     unsigned long write_size;
 466     BOOL result;
 467     DWORD error;
 468
 469 #ifdef TUN_ASYNCHRONOUS_WRITES
 470     result = GetOverlappedResult( overlapped->handle, &overlapped->write_overlapped,
 471                                   &write_size, FALSE);
 472
 473     if (!result && GetLastError() == ERROR_IO_INCOMPLETE)
 474         WaitForSingleObject(overlapped->write_event, INFINITE);
 475 #endif
 476
 477     result = WriteFile(overlapped->handle, buffer, size,
 478                        &write_size, &overlapped->write_overlapped);
 479
 480 #ifdef TUN_ASYNCHRONOUS_WRITES
 481     /* FIXME: we can't sensibly set write_size here, without waiting
 482      * for the IO to complete! Moreover, we can't return zero,
 483      * because that will disable receive on this interface, and we
 484      * also can't assume it will succeed and return the full size,
 485      * because that will result in the buffer being reclaimed while
 486      * the IO is in progress. */
 487 #error Async writes are broken. Please disable TUN_ASYNCHRONOUS_WRITES.
 488 #else /* !TUN_ASYNCHRONOUS_WRITES */
 489     if (!result) {
 490         error = GetLastError();
 491         if (error == ERROR_IO_PENDING) {
 492             result = GetOverlappedResult(overlapped->handle,
 493                                          &overlapped->write_overlapped,
 494                                          &write_size, TRUE);
 495         }
 496     }
 497 #endif
 498
 499     if (!result) {
 500 #ifdef DEBUG_TAP_WIN32
 501         LPTSTR msgbuf;
 502         error = GetLastError();
 503         FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM,
 504                       NULL, error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
 505                       &msgbuf, 0, NULL);
 506         fprintf(stderr, "Tap-Win32: Error WriteFile %d - %s\n", error, msgbuf);
 507         LocalFree(msgbuf);
 508 #endif
 509         return 0;
 510     }
 511
 512     return write_size;
 513 }
 514
 515 static DWORD WINAPI tap_win32_thread_entry(LPVOID param)
 516 {
 517     tap_win32_overlapped_t *overlapped = (tap_win32_overlapped_t*)param;
 518     unsigned long read_size;
 519     BOOL result;
 520     DWORD dwError;
 521     tun_buffer_t* buffer = get_buffer_from_free_list(overlapped);
 522
 523
 524     for (;;) {
 525         result = ReadFile(overlapped->handle,
 526                           buffer->buffer,
 527                           sizeof(buffer->buffer),
 528                           &read_size,
 529                           &overlapped->read_overlapped);
 530         if (!result) {
 531             dwError = GetLastError();
 532             if (dwError == ERROR_IO_PENDING) {
 533                 WaitForSingleObject(overlapped->read_event, INFINITE);
 534                 result = GetOverlappedResult( overlapped->handle, &overlapped->read_overlapped,
 535                                               &read_size, FALSE);
 536                 if (!result) {
 537 #ifdef DEBUG_TAP_WIN32
 538                     LPVOID lpBuffer;
 539                     dwError = GetLastError();
 540                     FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
 541                                    NULL, dwError, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
 542                                    (LPTSTR) & lpBuffer, 0, NULL );
 543                     fprintf(stderr, "Tap-Win32: Error GetOverlappedResult %d - %s\n", dwError, lpBuffer);
 544                     LocalFree( lpBuffer );
 545 #endif
 546                 }
 547             } else {
 548 #ifdef DEBUG_TAP_WIN32
 549                 LPVOID lpBuffer;
 550                 FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
 551                                NULL, dwError, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
 552                                (LPTSTR) & lpBuffer, 0, NULL );
 553                 fprintf(stderr, "Tap-Win32: Error ReadFile %d - %s\n", dwError, lpBuffer);
 554                 LocalFree( lpBuffer );
 555 #endif
 556             }
 557         }
 558
 559         if(read_size > 0) {
 560             buffer->read_size = read_size;
 561             put_buffer_on_output_queue(overlapped, buffer);
 562             ReleaseSemaphore(overlapped->tap_semaphore, 1, NULL);
 563             buffer = get_buffer_from_free_list(overlapped);
 564         }
 565     }
 566
 567     return 0;
 568 }
 569
 570 static int tap_win32_read(tap_win32_overlapped_t *overlapped,
 571                           uint8_t **pbuf, int max_size)
 572 {
 573     int size = 0;
 574
 575     tun_buffer_t* buffer = get_buffer_from_output_queue_immediate(overlapped);
 576
 577     if(buffer != NULL) {
 578         *pbuf = buffer->buffer;
 579         size = (int)buffer->read_size;
 580         if(size > max_size) {
 581             size = max_size;
 582         }
 583     }
 584
 585     return size;
 586 }
 587
 588 static void tap_win32_free_buffer(tap_win32_overlapped_t *overlapped,
 589                                   uint8_t *pbuf)
 590 {
 591     tun_buffer_t* buffer = (tun_buffer_t*)pbuf;
 592     put_buffer_on_free_list(overlapped, buffer);
 593 }
 594
 595 static int tap_win32_open(tap_win32_overlapped_t **phandle,
 596                           const char *preferred_name)
 597 {
 598     char device_path[256];
 599     char device_guid[0x100];
 600     int rc;
 601     HANDLE handle;
 602     BOOL bret;
 603     char name_buffer[0x100] = {0, };
 604     struct {
 605         unsigned long major;
 606         unsigned long minor;
 607         unsigned long debug;
 608     } version;
 609     DWORD version_len;
 610     DWORD idThread;
 611
 612     if (preferred_name != NULL) {
 613         snprintf(name_buffer, sizeof(name_buffer), "%s", preferred_name);
 614     }
 615
 616     rc = get_device_guid(device_guid, sizeof(device_guid), name_buffer, sizeof(name_buffer));
 617     if (rc)
 618         return -1;
 619
 620     snprintf (device_path, sizeof(device_path), "%s%s%s",
 621               USERMODEDEVICEDIR,
 622               device_guid,
 623               TAPSUFFIX);
 624
 625     handle = CreateFile (
 626         device_path,
 627         GENERIC_READ | GENERIC_WRITE,
 628         0,
 629         0,
 630         OPEN_EXISTING,
 631         FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED,
 632         0 );
 633
 634     if (handle == INVALID_HANDLE_VALUE) {
 635         return -1;
 636     }
 637
 638     bret = DeviceIoControl(handle, TAP_IOCTL_GET_VERSION,
 639                            &version, sizeof (version),
 640                            &version, sizeof (version), &version_len, NULL);
 641
 642     if (bret == FALSE) {
 643         CloseHandle(handle);
 644         return -1;
 645     }
 646
 647     if (!tap_win32_set_status(handle, TRUE)) {
 648         return -1;
 649     }
 650
 651     tap_win32_overlapped_init(&tap_overlapped, handle);
 652
 653     *phandle = &tap_overlapped;
 654
 655     CreateThread(NULL, 0, tap_win32_thread_entry,
 656                  (LPVOID)&tap_overlapped, 0, &idThread);
 657     return 0;
 658 }
 659
 660 /********************************************/
 661
 662  typedef struct TAPState {
 663      NetClientState nc;
 664      tap_win32_overlapped_t *handle;
 665  } TAPState;
 666
 667 static void tap_cleanup(NetClientState *nc)
 668 {
 669     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 670
 671     qemu_del_wait_object(s->handle->tap_semaphore, NULL, NULL);
 672
 673     /* FIXME: need to kill thread and close file handle:
 674        tap_win32_close(s);
 675     */
 676 }
 677
 678 static ssize_t tap_receive(NetClientState *nc, const uint8_t *buf, size_t size)
 679 {
 680     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 681
 682     return tap_win32_write(s->handle, buf, size);
 683 }
 684
 685 static void tap_win32_send(void *opaque)
 686 {
 687     TAPState *s = opaque;
 688     uint8_t *buf;
 689     int max_size = 4096;
 690     int size;
 691
 692     size = tap_win32_read(s->handle, &buf, max_size);
 693     if (size > 0) {
 694         qemu_send_packet(&s->nc, buf, size);
 695         tap_win32_free_buffer(s->handle, buf);
 696     }
 697 }
 698
 699 static bool tap_has_ufo(NetClientState *nc)
 700 {
 701     return false;
 702 }
 703
 704 static bool tap_has_vnet_hdr(NetClientState *nc)
 705 {
 706     return false;
 707 }
 708
 709 int tap_probe_vnet_hdr_len(int fd, int len)
 710 {
 711     return 0;
 712 }
 713
 714 void tap_fd_set_vnet_hdr_len(int fd, int len)
 715 {
 716 }
 717
 718 int tap_fd_set_vnet_le(int fd, int is_le)
 719 {
 720     return -EINVAL;
 721 }
 722
 723 int tap_fd_set_vnet_be(int fd, int is_be)
 724 {
 725     return -EINVAL;
 726 }
 727
 728 static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 729 {
 730 }
 731
 732 static void tap_set_offload(NetClientState *nc, int csum, int tso4,
 733                      int tso6, int ecn, int ufo)
 734 {
 735 }
 736
 737 struct vhost_net *tap_get_vhost_net(NetClientState *nc)
 738 {
 739     return NULL;
 740 }
 741
 742 static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
 743 {
 744     return false;
 745 }
 746
 747 static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 748 {
 749     abort();
 750 }
 751
 752 static NetClientInfo net_tap_win32_info = {
 753     .type = NET_CLIENT_DRIVER_TAP,
 754     .size = sizeof(TAPState),
 755     .receive = tap_receive,
 756     .cleanup = tap_cleanup,
 757     .has_ufo = tap_has_ufo,
 758     .has_vnet_hdr = tap_has_vnet_hdr,
 759     .has_vnet_hdr_len = tap_has_vnet_hdr_len,
 760     .using_vnet_hdr = tap_using_vnet_hdr,
 761     .set_offload = tap_set_offload,
 762     .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 763 };
 764
 765 static int tap_win32_init(NetClientState *peer, const char *model,
 766                           const char *name, const char *ifname)
 767 {
 768     NetClientState *nc;
 769     TAPState *s;
 770     tap_win32_overlapped_t *handle;
 771
 772     if (tap_win32_open(&handle, ifname) < 0) {
 773         printf("tap: Could not open '%s'\n", ifname);
 774         return -1;
 775     }
 776
 777     nc = qemu_new_net_client(&net_tap_win32_info, peer, model, name);
 778
 779     s = DO_UPCAST(TAPState, nc, nc);
 780
 781     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 782              "tap: ifname=%s", ifname);
 783
 784     s->handle = handle;
 785
 786     qemu_add_wait_object(s->handle->tap_semaphore, tap_win32_send, s);
 787
 788     return 0;
 789 }
 790
 791 int net_init_tap(const Netdev *netdev, const char *name,
 792                  NetClientState *peer, Error **errp)
 793 {
 794     /* FIXME error_setg(errp, ...) on failure */
 795     const NetdevTapOptions *tap;
 796
 797     assert(netdev->type == NET_CLIENT_DRIVER_TAP);
 798     tap = &netdev->u.tap;
 799
 800     if (!tap->has_ifname) {
 801         error_report("tap: no interface name");
 802         return -1;
 803     }
 804
 805     if (tap_win32_init(peer, "tap", name, tap->ifname) == -1) {
 806         return -1;
 807     }
 808
 809     return 0;
 810 }
 811
 812 int tap_enable(NetClientState *nc)
 813 {
 814     abort();
 815 }
 816
 817 int tap_disable(NetClientState *nc)
 818 {
 819     abort();
 820 }