/*

 *  TAP-Win32 -- A kernel driver to provide virtual tap device functionality

 *               on Windows.  Originally derived from the CIPE-Win32

 *               project by Damion K. Wilson, with extensive modifications by

 *               James Yonan.

 *

 *  All source code which derives from the CIPE-Win32 project is

 *  Copyright (C) Damion K. Wilson, 2003, and is released under the

 *  GPL version 2 (see below).

 *

 *  All other source code is Copyright (C) James Yonan, 2003-2004,

 *  and is released under the GPL version 2 (see below).

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program (see the file COPYING included with this

 *  distribution); if not, write to the Free Software Foundation, Inc.,

 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include "qemu-common.h"

#include "net.h"

#include "sysemu.h"

#include <stdio.h>

#define WIN32_LEAN_AND_MEAN

#include <windows.h>

/* NOTE: PCIBus is redefined in winddk.h */

#define PCIBus _PCIBus

#include <ddk/ntapi.h>

#include <ddk/winddk.h>

#include <ddk/ntddk.h>

#undef PCIBus

//=============

// TAP IOCTLs

//=============

#define TAP_CONTROL_CODE(request,method) \

  CTL_CODE (FILE_DEVICE_UNKNOWN, request, method, FILE_ANY_ACCESS)

#define TAP_IOCTL_GET_MAC               TAP_CONTROL_CODE (1, METHOD_BUFFERED)

#define TAP_IOCTL_GET_VERSION           TAP_CONTROL_CODE (2, METHOD_BUFFERED)

#define TAP_IOCTL_GET_MTU               TAP_CONTROL_CODE (3, METHOD_BUFFERED)

#define TAP_IOCTL_GET_INFO              TAP_CONTROL_CODE (4, METHOD_BUFFERED)

#define TAP_IOCTL_CONFIG_POINT_TO_POINT TAP_CONTROL_CODE (5, METHOD_BUFFERED)

#define TAP_IOCTL_SET_MEDIA_STATUS      TAP_CONTROL_CODE (6, METHOD_BUFFERED)

#define TAP_IOCTL_CONFIG_DHCP_MASQ      TAP_CONTROL_CODE (7, METHOD_BUFFERED)

#define TAP_IOCTL_GET_LOG_LINE          TAP_CONTROL_CODE (8, METHOD_BUFFERED)

#define TAP_IOCTL_CONFIG_DHCP_SET_OPT   TAP_CONTROL_CODE (9, METHOD_BUFFERED)

//=================

// Registry keys

//=================

#define ADAPTER_KEY "SYSTEM\\CurrentControlSet\\Control\\Class\\{4D36E972-E325-11CE-BFC1-08002BE10318}"

#define NETWORK_CONNECTIONS_KEY "SYSTEM\\CurrentControlSet\\Control\\Network\\{4D36E972-E325-11CE-BFC1-08002BE10318}"

//======================

// Filesystem prefixes

//======================

#define USERMODEDEVICEDIR "\\\\.\\Global\\"

#define TAPSUFFIX         ".tap"

//======================

// Compile time configuration

//======================

//#define DEBUG_TAP_WIN32

#define TUN_ASYNCHRONOUS_WRITES 1

#define TUN_BUFFER_SIZE 1560

#define TUN_MAX_BUFFER_COUNT 32

/*

 * The data member "buffer" must be the first element in the tun_buffer

 * structure. See the function, tap_win32_free_buffer.

 */

typedef struct tun_buffer_s {

    unsigned char buffer [TUN_BUFFER_SIZE];

    unsigned long read_size;

    struct tun_buffer_s* next;

} tun_buffer_t;

typedef struct tap_win32_overlapped {

    HANDLE handle;

    HANDLE read_event;

    HANDLE write_event;

    HANDLE output_queue_semaphore;

    HANDLE free_list_semaphore;

    HANDLE tap_semaphore;

    CRITICAL_SECTION output_queue_cs;

    CRITICAL_SECTION free_list_cs;

    OVERLAPPED read_overlapped;

    OVERLAPPED write_overlapped;

    tun_buffer_t buffers[TUN_MAX_BUFFER_COUNT];

    tun_buffer_t* free_list;

    tun_buffer_t* output_queue_front;

    tun_buffer_t* output_queue_back;

} tap_win32_overlapped_t;

static tap_win32_overlapped_t tap_overlapped;

static tun_buffer_t* get_buffer_from_free_list(tap_win32_overlapped_t* const overlapped)

{

    tun_buffer_t* buffer = NULL;

    WaitForSingleObject(overlapped->free_list_semaphore, INFINITE);

    EnterCriticalSection(&overlapped->free_list_cs);

    buffer = overlapped->free_list;

//    assert(buffer != NULL);

    overlapped->free_list = buffer->next;

    LeaveCriticalSection(&overlapped->free_list_cs);

    buffer->next = NULL;

    return buffer;

}

static void put_buffer_on_free_list(tap_win32_overlapped_t* const overlapped, tun_buffer_t* const buffer)

{

    EnterCriticalSection(&overlapped->free_list_cs);

    buffer->next = overlapped->free_list;

    overlapped->free_list = buffer;

    LeaveCriticalSection(&overlapped->free_list_cs);

    ReleaseSemaphore(overlapped->free_list_semaphore, 1, NULL);

}

static tun_buffer_t* get_buffer_from_output_queue(tap_win32_overlapped_t* const overlapped, const int block)

{

    tun_buffer_t* buffer = NULL;

    DWORD result, timeout = block ? INFINITE : 0L;

    // Non-blocking call

    result = WaitForSingleObject(overlapped->output_queue_semaphore, timeout);

    switch (result)

    {

        // The semaphore object was signaled.

        case WAIT_OBJECT_0:

            EnterCriticalSection(&overlapped->output_queue_cs);

            buffer = overlapped->output_queue_front;

            overlapped->output_queue_front = buffer->next;

            if(overlapped->output_queue_front == NULL) {

                overlapped->output_queue_back = NULL;

            }

            LeaveCriticalSection(&overlapped->output_queue_cs);

            break;

        // Semaphore was nonsignaled, so a time-out occurred.

        case WAIT_TIMEOUT:

            // Cannot open another window.

            break;

    }

    return buffer;

}

static tun_buffer_t* get_buffer_from_output_queue_immediate (tap_win32_overlapped_t* const overlapped)

{

    return get_buffer_from_output_queue(overlapped, 0);

}

static void put_buffer_on_output_queue(tap_win32_overlapped_t* const overlapped, tun_buffer_t* const buffer)

{

    EnterCriticalSection(&overlapped->output_queue_cs);

    if(overlapped->output_queue_front == NULL && overlapped->output_queue_back == NULL) {

        overlapped->output_queue_front = overlapped->output_queue_back = buffer;

    } else {

        buffer->next = NULL;

        overlapped->output_queue_back->next = buffer;

        overlapped->output_queue_back = buffer;

    }

    LeaveCriticalSection(&overlapped->output_queue_cs);

    ReleaseSemaphore(overlapped->output_queue_semaphore, 1, NULL);

}

static int is_tap_win32_dev(const char *guid)

{

    HKEY netcard_key;

    LONG status;

    DWORD len;

    int i = 0;

    status = RegOpenKeyEx(

        HKEY_LOCAL_MACHINE,

        ADAPTER_KEY,

        0,

        KEY_READ,

        &netcard_key);

    if (status != ERROR_SUCCESS) {

        return FALSE;

    }

    for (;;) {

        char enum_name[256];

        char unit_string[256];

        HKEY unit_key;

        char component_id_string[] = "ComponentId";

        char component_id[256];

        char net_cfg_instance_id_string[] = "NetCfgInstanceId";

        char net_cfg_instance_id[256];

        DWORD data_type;

        len = sizeof (enum_name);

        status = RegEnumKeyEx(

            netcard_key,

            i,

            enum_name,

            &len,

            NULL,

            NULL,

            NULL,

            NULL);

        if (status == ERROR_NO_MORE_ITEMS)

            break;

        else if (status != ERROR_SUCCESS) {

            return FALSE;

        }

        snprintf (unit_string, sizeof(unit_string), "%s\\%s",

                  ADAPTER_KEY, enum_name);

        status = RegOpenKeyEx(

            HKEY_LOCAL_MACHINE,

            unit_string,

            0,

            KEY_READ,

            &unit_key);

        if (status != ERROR_SUCCESS) {

            return FALSE;

        } else {

            len = sizeof (component_id);

            status = RegQueryValueEx(

                unit_key,

                component_id_string,

                NULL,

                &data_type,

                component_id,

                &len);

            if (!(status != ERROR_SUCCESS || data_type != REG_SZ)) {

                len = sizeof (net_cfg_instance_id);

                status = RegQueryValueEx(

                    unit_key,

                    net_cfg_instance_id_string,

                    NULL,

                    &data_type,

                    net_cfg_instance_id,

                    &len);

                if (status == ERROR_SUCCESS && data_type == REG_SZ) {

                    if (/* !strcmp (component_id, TAP_COMPONENT_ID) &&*/

                        !strcmp (net_cfg_instance_id, guid)) {

                        RegCloseKey (unit_key);

                        RegCloseKey (netcard_key);

                        return TRUE;

                    }

                }

            }

            RegCloseKey (unit_key);

        }

        ++i;

    }

    RegCloseKey (netcard_key);

    return FALSE;

}

static int get_device_guid(

    char *name,

    int name_size,

    char *actual_name,

    int actual_name_size)

{

    LONG status;

    HKEY control_net_key;

    DWORD len;

    int i = 0;

    int stop = 0;

    status = RegOpenKeyEx(

        HKEY_LOCAL_MACHINE,

        NETWORK_CONNECTIONS_KEY,

        0,

        KEY_READ,

        &control_net_key);

    if (status != ERROR_SUCCESS) {

        return -1;

    }

    while (!stop)

    {

        char enum_name[256];

        char connection_string[256];

        HKEY connection_key;

        char name_data[256];

        DWORD name_type;

        const char name_string[] = "Name";

        len = sizeof (enum_name);

        status = RegEnumKeyEx(

            control_net_key,

            i,

            enum_name,

            &len,

            NULL,

            NULL,

            NULL,

            NULL);

        if (status == ERROR_NO_MORE_ITEMS)

            break;

        else if (status != ERROR_SUCCESS) {

            return -1;

        }

        snprintf(connection_string,

             sizeof(connection_string),

             "%s\\%s\\Connection",

             NETWORK_CONNECTIONS_KEY, enum_name);

        status = RegOpenKeyEx(

            HKEY_LOCAL_MACHINE,

            connection_string,

            0,

            KEY_READ,

            &connection_key);

        if (status == ERROR_SUCCESS) {

            len = sizeof (name_data);

            status = RegQueryValueEx(

                connection_key,

                name_string,

                NULL,

                &name_type,

                name_data,

                &len);

            if (status != ERROR_SUCCESS || name_type != REG_SZ) {

                    return -1;

            }

            else {

                if (is_tap_win32_dev(enum_name)) {

                    snprintf(name, name_size, "%s", enum_name);

                    if (actual_name) {

                        if (strcmp(actual_name, "") != 0) {

                            if (strcmp(name_data, actual_name) != 0) {

                                RegCloseKey (connection_key);

                                ++i;

                                continue;

                            }

                        }

                        else {

                            snprintf(actual_name, actual_name_size, "%s", name_data);

                        }

                    }

                    stop = 1;

                }

            }

            RegCloseKey (connection_key);

        }

        ++i;

    }

    RegCloseKey (control_net_key);

    if (stop == 0)

        return -1;

    return 0;

}

static int tap_win32_set_status(HANDLE handle, int status)

{

    unsigned long len = 0;

    return DeviceIoControl(handle, TAP_IOCTL_SET_MEDIA_STATUS,

                &status, sizeof (status),

                &status, sizeof (status), &len, NULL);

}

static void tap_win32_overlapped_init(tap_win32_overlapped_t* const overlapped, const HANDLE handle)

{

    overlapped->handle = handle;

    overlapped->read_event = CreateEvent(NULL, FALSE, FALSE, NULL);

    overlapped->write_event = CreateEvent(NULL, FALSE, FALSE, NULL);

    overlapped->read_overlapped.Offset = 0;

    overlapped->read_overlapped.OffsetHigh = 0;

    overlapped->read_overlapped.hEvent = overlapped->read_event;

    overlapped->write_overlapped.Offset = 0;

    overlapped->write_overlapped.OffsetHigh = 0;

    overlapped->write_overlapped.hEvent = overlapped->write_event;

    InitializeCriticalSection(&overlapped->output_queue_cs);

    InitializeCriticalSection(&overlapped->free_list_cs);

    overlapped->output_queue_semaphore = CreateSemaphore(

        NULL,   // default security attributes

        0,   // initial count

        TUN_MAX_BUFFER_COUNT,   // maximum count

        NULL);  // unnamed semaphore

    if(!overlapped->output_queue_semaphore)  {

        fprintf(stderr, "error creating output queue semaphore!\n");

    }

    overlapped->free_list_semaphore = CreateSemaphore(

        NULL,   // default security attributes

        TUN_MAX_BUFFER_COUNT,   // initial count

        TUN_MAX_BUFFER_COUNT,   // maximum count

        NULL);  // unnamed semaphore

    if(!overlapped->free_list_semaphore)  {

        fprintf(stderr, "error creating free list semaphore!\n");

    }

    overlapped->free_list = overlapped->output_queue_front = overlapped->output_queue_back = NULL;

    {

        unsigned index;

        for(index = 0; index < TUN_MAX_BUFFER_COUNT; index++) {

            tun_buffer_t* element = &overlapped->buffers[index];

            element->next = overlapped->free_list;

            overlapped->free_list = element;

        }

    }

    /* To count buffers, initially no-signal. */

    overlapped->tap_semaphore = CreateSemaphore(NULL, 0, TUN_MAX_BUFFER_COUNT, NULL);

    if(!overlapped->tap_semaphore)

        fprintf(stderr, "error creating tap_semaphore.\n");

}

static int tap_win32_write(tap_win32_overlapped_t *overlapped,

                           const void *buffer, unsigned long size)

{

    unsigned long write_size;

    BOOL result;

    DWORD error;

    result = GetOverlappedResult( overlapped->handle, &overlapped->write_overlapped,

                                  &write_size, FALSE);

    if (!result && GetLastError() == ERROR_IO_INCOMPLETE)

        WaitForSingleObject(overlapped->write_event, INFINITE);

    result = WriteFile(overlapped->handle, buffer, size,

                       &write_size, &overlapped->write_overlapped);

    if (!result) {

        switch (error = GetLastError())

        {

        case ERROR_IO_PENDING:

#ifndef TUN_ASYNCHRONOUS_WRITES

            WaitForSingleObject(overlapped->write_event, INFINITE);

#endif

            break;

        default:

            return -1;

        }

    }

    return 0;

}

static DWORD WINAPI tap_win32_thread_entry(LPVOID param)

{

    tap_win32_overlapped_t *overlapped = (tap_win32_overlapped_t*)param;

    unsigned long read_size;

    BOOL result;

    DWORD dwError;

    tun_buffer_t* buffer = get_buffer_from_free_list(overlapped);

    for (;;) {

        result = ReadFile(overlapped->handle,

                          buffer->buffer,

                          sizeof(buffer->buffer),

                          &read_size,

                          &overlapped->read_overlapped);

        if (!result) {

            dwError = GetLastError();

            if (dwError == ERROR_IO_PENDING) {

                WaitForSingleObject(overlapped->read_event, INFINITE);

                result = GetOverlappedResult( overlapped->handle, &overlapped->read_overlapped,

                                              &read_size, FALSE);

                if (!result) {

#ifdef DEBUG_TAP_WIN32

                    LPVOID lpBuffer;

                    dwError = GetLastError();

                    FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,

                                   NULL, dwError, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),

                                   (LPTSTR) & lpBuffer, 0, NULL );

                    fprintf(stderr, "Tap-Win32: Error GetOverlappedResult %d - %s\n", dwError, lpBuffer);

                    LocalFree( lpBuffer );

#endif

                }

            } else {

#ifdef DEBUG_TAP_WIN32

                LPVOID lpBuffer;

                FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,

                               NULL, dwError, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),

                               (LPTSTR) & lpBuffer, 0, NULL );

                fprintf(stderr, "Tap-Win32: Error ReadFile %d - %s\n", dwError, lpBuffer);

                LocalFree( lpBuffer );