tap.c

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/*
 *  tapctl -- Utility to manipulate TUN/TAP adapters on Windows
 *            https://community.openvpn.net/openvpn/wiki/Tapctl
 *
 *  Copyright (C) 2018-2026 Simon Rozman <simon@rozman.si>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  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; if not, see <https://www.gnu.org/licenses/>.
 */
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
 
#include "tap.h"
#include "error.h"
 
#include <windows.h>
#include <cfgmgr32.h>
#include <objbase.h>
#include <setupapi.h>
#include <stdio.h>
#include <wchar.h>
#include <newdev.h>
 
#ifdef _MSC_VER
#pragma comment(lib, "advapi32.lib")
#pragma comment(lib, "ole32.lib")
#pragma comment(lib, "setupapi.lib")
#pragma comment(lib, "newdev.lib")
#endif
 
 
static const GUID GUID_DEVCLASS_NET = {
    0x4d36e972L, 0xe325, 0x11ce, { 0xbf, 0xc1, 0x08, 0x00, 0x2b, 0xe1, 0x03, 0x18 }
};
 
static const WCHAR szAdapterRegKeyPathTemplate[] =
    L"SYSTEM\\CurrentControlSet\\Control\\Network\\%ls\\%ls\\Connection";
#define ADAPTER_REGKEY_PATH_MAX                                                                \
    (_countof(L"SYSTEM\\CurrentControlSet\\Control\\Network\\") - 1 + 38 + _countof(L"\\") - 1 \
     + 38 + _countof(L"\\Connection"))
 
static void *
find_function(const WCHAR *libname, const char *funcname, HMODULE *m)
{
    WCHAR libpath[MAX_PATH];
    void *fptr = NULL;
 
    /* Make sure the dll is loaded from the system32 folder */
    if (!GetSystemDirectoryW(libpath, _countof(libpath)))
    {
        return NULL;
    }
 
    /* +1 for the path seperator '\' */
    const size_t path_length = wcslen(libpath) + 1 + wcslen(libname);
    if (path_length >= _countof(libpath))
    {
        SetLastError(ERROR_INSUFFICIENT_BUFFER);
        return NULL;
    }
    wcscat_s(libpath, _countof(libpath), L"\\");
    wcscat_s(libpath, _countof(libpath), libname);
 
    *m = LoadLibraryW(libpath);
    if (*m == NULL)
    {
        return NULL;
    }
    fptr = GetProcAddress(*m, funcname);
    if (!fptr)
    {
        FreeLibrary(*m);
        *m = NULL;
        return NULL;
    }
    return fptr;
}
 
static inline size_t
wcszlen(_In_z_ LPCWSTR szz)
{
    LPCWSTR s;
    for (s = szz; s[0]; s += wcslen(s) + 1)
    {
    }
    return s - szz;
}
 
 
static LPCWSTR
wcszistr(_In_z_ LPCWSTR szzHay, _In_z_ LPCWSTR szNeedle)
{
    for (LPCWSTR s = szzHay; s[0]; s += wcslen(s) + 1)
    {
        if (wcsicmp(s, szNeedle) == 0)
        {
            return s;
        }
    }
 
    return NULL;
}
 
 
typedef DWORD (*devop_func_t)(_In_ HDEVINFO hDeviceInfoSet, _In_ PSP_DEVINFO_DATA pDeviceInfoData,
                              _Inout_ LPBOOL pbRebootRequired);
 
 
static DWORD
check_reboot(_In_ HDEVINFO hDeviceInfoSet, _In_ PSP_DEVINFO_DATA pDeviceInfoData,
             _Inout_ LPBOOL pbRebootRequired)
{
    if (pbRebootRequired == NULL)
    {
        return ERROR_BAD_ARGUMENTS;
    }
 
    SP_DEVINSTALL_PARAMS devinstall_params = { .cbSize = sizeof(SP_DEVINSTALL_PARAMS) };
    if (!SetupDiGetDeviceInstallParams(hDeviceInfoSet, pDeviceInfoData, &devinstall_params))
    {
        DWORD dwResult = GetLastError();
        msg(M_NONFATAL | M_ERRNO, "%s: SetupDiGetDeviceInstallParams failed", __FUNCTION__);
        return dwResult;
    }
 
    if ((devinstall_params.Flags & (DI_NEEDREBOOT | DI_NEEDRESTART)) != 0)
    {
        *pbRebootRequired = TRUE;
    }
 
    return ERROR_SUCCESS;
}
 
 
static DWORD
delete_device(_In_ HDEVINFO hDeviceInfoSet, _In_ PSP_DEVINFO_DATA pDeviceInfoData,
              _Inout_ LPBOOL pbRebootRequired)
{
    SP_REMOVEDEVICE_PARAMS params = {
        .ClassInstallHeader = {
            .cbSize = sizeof(SP_CLASSINSTALL_HEADER),
            .InstallFunction = DIF_REMOVE,
        },
        .Scope = DI_REMOVEDEVICE_GLOBAL,
        .HwProfile = 0,
    };
 
    /* Set class installer parameters for DIF_REMOVE. */
    if (!SetupDiSetClassInstallParams(hDeviceInfoSet, pDeviceInfoData, &params.ClassInstallHeader,
                                      sizeof(SP_REMOVEDEVICE_PARAMS)))
    {
        DWORD dwResult = GetLastError();
        msg(M_NONFATAL | M_ERRNO, "%s: SetupDiSetClassInstallParams failed", __FUNCTION__);
        return dwResult;
    }
 
    /* Call appropriate class installer. */
    if (!SetupDiCallClassInstaller(DIF_REMOVE, hDeviceInfoSet, pDeviceInfoData))
    {
        DWORD dwResult = GetLastError();
        msg(M_NONFATAL | M_ERRNO, "%s: SetupDiCallClassInstaller(DIF_REMOVE) failed", __FUNCTION__);
        return dwResult;
    }
 
    /* Check if a system reboot is required. */
    check_reboot(hDeviceInfoSet, pDeviceInfoData, pbRebootRequired);
    return ERROR_SUCCESS;
}
 
 
static DWORD
change_device_state(_In_ HDEVINFO hDeviceInfoSet, _In_ PSP_DEVINFO_DATA pDeviceInfoData,
                    _In_ BOOL bEnable, _Inout_ LPBOOL pbRebootRequired)
{
    SP_PROPCHANGE_PARAMS params = {
        .ClassInstallHeader = {
            .cbSize = sizeof(SP_CLASSINSTALL_HEADER),
            .InstallFunction = DIF_PROPERTYCHANGE,
        },
        .StateChange = bEnable ? DICS_ENABLE : DICS_DISABLE,
        .Scope = DICS_FLAG_GLOBAL,
        .HwProfile = 0,
    };
 
    /* Set class installer parameters for DIF_PROPERTYCHANGE. */
    if (!SetupDiSetClassInstallParams(hDeviceInfoSet, pDeviceInfoData, &params.ClassInstallHeader,
                                      sizeof(SP_PROPCHANGE_PARAMS)))
    {
        DWORD dwResult = GetLastError();
        msg(M_NONFATAL | M_ERRNO, "%s: SetupDiSetClassInstallParams failed", __FUNCTION__);
        return dwResult;
    }
 
    /* Call appropriate class installer. */
    if (!SetupDiCallClassInstaller(DIF_PROPERTYCHANGE, hDeviceInfoSet, pDeviceInfoData))
    {
        DWORD dwResult = GetLastError();
        msg(M_NONFATAL | M_ERRNO, "%s: SetupDiCallClassInstaller(DIF_PROPERTYCHANGE) failed",
            __FUNCTION__);
        return dwResult;
    }
 
    /* Check if a system reboot is required. */
    check_reboot(hDeviceInfoSet, pDeviceInfoData, pbRebootRequired);
    return ERROR_SUCCESS;
}
 
 
static DWORD
enable_device(_In_ HDEVINFO hDeviceInfoSet, _In_ PSP_DEVINFO_DATA pDeviceInfoData,
              _Inout_ LPBOOL pbRebootRequired)
{
    return change_device_state(hDeviceInfoSet, pDeviceInfoData, TRUE, pbRebootRequired);
}
 
 
static DWORD
disable_device(_In_ HDEVINFO hDeviceInfoSet, _In_ PSP_DEVINFO_DATA pDeviceInfoData,
               _Inout_ LPBOOL pbRebootRequired)
{
    return change_device_state(hDeviceInfoSet, pDeviceInfoData, FALSE, pbRebootRequired);
}
 
 
static DWORD
get_reg_string(_In_ HKEY hKey, _In_ LPCWSTR szName, _Out_ LPWSTR *pszValue)
{
    if (pszValue == NULL)
    {
        return ERROR_BAD_ARGUMENTS;
    }
 
    DWORD dwValueType = REG_NONE, dwSize = 0;
    DWORD dwResult = RegQueryValueEx(hKey, szName, NULL, &dwValueType, NULL, &dwSize);
    if (dwResult != ERROR_SUCCESS)
    {
        SetLastError(dwResult); /* MSDN does not mention RegQueryValueEx() to set GetLastError().
                                   But we do have an error code. Set last error manually. */
        msg(M_NONFATAL | M_ERRNO, "%s: enumerating \"%ls\" registry value failed", __FUNCTION__,
            szName);
        return dwResult;
    }
 
    switch (dwValueType)
    {
        case REG_SZ:
        case REG_EXPAND_SZ:
        {
            /* Read value. */
            LPWSTR szValue = (LPWSTR)malloc(dwSize);
            if (szValue == NULL)
            {
                msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwSize);
                return ERROR_OUTOFMEMORY;
            }
 
            dwResult = RegQueryValueEx(hKey, szName, NULL, NULL, (LPBYTE)szValue, &dwSize);
            if (dwResult != ERROR_SUCCESS)
            {
                SetLastError(
                    dwResult); /* MSDN does not mention RegQueryValueEx() to set GetLastError(). But
                                  we do have an error code. Set last error manually. */
                msg(M_NONFATAL | M_ERRNO, "%s: reading \"%ls\" registry value failed", __FUNCTION__,
                    szName);
                free(szValue);
                return dwResult;
            }
 
            if (dwValueType == REG_EXPAND_SZ)
            {
                /* Expand the environment strings. */
                DWORD
                dwSizeExp = dwSize * 2, dwCountExp =
#ifdef UNICODE
                                            dwSizeExp / sizeof(WCHAR);
#else
                                            dwSizeExp / sizeof(WCHAR)
                                            - 1; /* Note: ANSI version requires one extra char. */
#endif
                LPWSTR szValueExp = (LPWSTR)malloc(dwSizeExp);
                if (szValueExp == NULL)
                {
                    free(szValue);
                    msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwSizeExp);
                    return ERROR_OUTOFMEMORY;
                }
 
                DWORD dwCountExpResult = ExpandEnvironmentStrings(szValue, szValueExp, dwCountExp);
                if (dwCountExpResult == 0)
                {
                    msg(M_NONFATAL | M_ERRNO, "%s: expanding \"%ls\" registry value failed",
                        __FUNCTION__, szName);
                    free(szValueExp);
                    free(szValue);
                    return dwResult;
                }
                else if (dwCountExpResult <= dwCountExp)
                {
                    /* The buffer was big enough. */
                    free(szValue);
                    *pszValue = szValueExp;
                    return ERROR_SUCCESS;
                }
                else
                {
                    /* Retry with a bigger buffer. */
                    free(szValueExp);
#ifdef UNICODE
                    dwSizeExp = dwCountExpResult * sizeof(WCHAR);
#else
                    /* Note: ANSI version requires one extra char. */
                    dwSizeExp = (dwCountExpResult + 1) * sizeof(WCHAR);
#endif
                    dwCountExp = dwCountExpResult;
                    szValueExp = (LPWSTR)malloc(dwSizeExp);
                    if (szValueExp == NULL)
                    {
                        free(szValue);
                        msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwSizeExp);
                        return ERROR_OUTOFMEMORY;
                    }
 
                    dwCountExpResult = ExpandEnvironmentStrings(szValue, szValueExp, dwCountExp);
                    free(szValue);
                    *pszValue = szValueExp;
                    return ERROR_SUCCESS;
                }
            }
            else
            {
                *pszValue = szValue;
                return ERROR_SUCCESS;
            }
        }
 
        default:
            msg(M_NONFATAL, "%s: \"%ls\" registry value is not string (type %u)",
                __FUNCTION__, szName, dwValueType);
            return ERROR_UNSUPPORTED_TYPE;
    }
}
 
 
static DWORD
get_net_adapter_guid(_In_ HDEVINFO hDeviceInfoSet, _In_ PSP_DEVINFO_DATA pDeviceInfoData,
                     _In_ int iNumAttempts, _Out_ LPGUID pguidAdapter)
{
    DWORD dwResult = ERROR_BAD_ARGUMENTS;
 
    if (pguidAdapter == NULL || iNumAttempts < 1)
    {
        return ERROR_BAD_ARGUMENTS;
    }
 
    /* Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class<class><id> registry key. */
    HKEY hKey = SetupDiOpenDevRegKey(hDeviceInfoSet, pDeviceInfoData, DICS_FLAG_GLOBAL, 0,
                                     DIREG_DRV, KEY_READ);
    if (hKey == INVALID_HANDLE_VALUE)
    {
        dwResult = GetLastError();
        msg(M_NONFATAL | M_ERRNO, "%s: SetupDiOpenDevRegKey failed", __FUNCTION__);
        return dwResult;
    }
 
    while (iNumAttempts > 0)
    {
        /* Query the NetCfgInstanceId value. Using get_reg_string() right on might clutter the
         * output with error messages while the registry is still being populated. */
        LPWSTR szCfgGuidString = NULL;
        dwResult = RegQueryValueEx(hKey, L"NetCfgInstanceId", NULL, NULL, NULL, NULL);
        if (dwResult != ERROR_SUCCESS)
        {
            if (dwResult == ERROR_FILE_NOT_FOUND && --iNumAttempts > 0)
            {
                /* Wait and retry. */
                Sleep(1000);
                continue;
            }
 
            SetLastError(
                dwResult); /* MSDN does not mention RegQueryValueEx() to set GetLastError(). But we
                              do have an error code. Set last error manually. */
            msg(M_NONFATAL | M_ERRNO, "%s: querying \"NetCfgInstanceId\" registry value failed",
                __FUNCTION__);
            break;
        }
 
        /* Read the NetCfgInstanceId value now. */
        dwResult = get_reg_string(hKey, L"NetCfgInstanceId", &szCfgGuidString);
        if (dwResult != ERROR_SUCCESS)
        {
            break;
        }
 
        dwResult = SUCCEEDED(CLSIDFromString(szCfgGuidString, (LPCLSID)pguidAdapter))
                       ? ERROR_SUCCESS
                       : ERROR_INVALID_DATA;
        free(szCfgGuidString);
        break;
    }
 
    RegCloseKey(hKey);
    return dwResult;
}
 
 
static DWORD
get_device_reg_property(_In_ HDEVINFO hDeviceInfoSet, _In_ PSP_DEVINFO_DATA pDeviceInfoData,
                        _In_ DWORD dwProperty, _Out_opt_ LPDWORD pdwPropertyRegDataType,
                        _Out_ LPVOID *ppData)
{
    DWORD dwResult = ERROR_BAD_ARGUMENTS;
 
    if (ppData == NULL)
    {
        return ERROR_BAD_ARGUMENTS;
    }
 
    /* Try with stack buffer first. */
    BYTE bBufStack[128];
    DWORD dwRequiredSize = 0;
    if (SetupDiGetDeviceRegistryProperty(hDeviceInfoSet, pDeviceInfoData, dwProperty,
                                         pdwPropertyRegDataType, bBufStack, sizeof(bBufStack),
                                         &dwRequiredSize))
    {
        /* Copy from stack. */
        *ppData = malloc(dwRequiredSize);
        if (*ppData == NULL)
        {
            msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwRequiredSize);
            return ERROR_OUTOFMEMORY;
        }
 
        memcpy(*ppData, bBufStack, dwRequiredSize);
        return ERROR_SUCCESS;
    }
    else
    {
        dwResult = GetLastError();
        if (dwResult == ERROR_INSUFFICIENT_BUFFER)
        {
            /* Allocate on heap and retry. */
            *ppData = malloc(dwRequiredSize);
            if (*ppData == NULL)
            {
                msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__, dwRequiredSize);
                return ERROR_OUTOFMEMORY;
            }
 
            if (SetupDiGetDeviceRegistryProperty(hDeviceInfoSet, pDeviceInfoData, dwProperty,
                                                 pdwPropertyRegDataType, *ppData, dwRequiredSize,
                                                 &dwRequiredSize))
            {
                return ERROR_SUCCESS;
            }
            else
            {
                dwResult = GetLastError();
                msg(M_NONFATAL | M_ERRNO, "%s: SetupDiGetDeviceRegistryProperty(%u) failed",
                    __FUNCTION__, dwProperty);
                return dwResult;
            }
        }
        else
        {
            msg(M_NONFATAL | M_ERRNO, "%s: SetupDiGetDeviceRegistryProperty(%u) failed",
                __FUNCTION__, dwProperty);
            return dwResult;
        }
    }
}
 
 
DWORD
tap_create_adapter(_In_opt_ HWND hwndParent, _In_opt_ LPCWSTR szDeviceDescription,
                   _In_ LPCWSTR szHwId, _Inout_ LPBOOL pbRebootRequired, _Out_ LPGUID pguidAdapter)
{
    DWORD dwResult;
    HMODULE libnewdev = NULL;
 
    if (szHwId == NULL || pbRebootRequired == NULL || pguidAdapter == NULL)
    {
        return ERROR_BAD_ARGUMENTS;
    }
 
    /* Create an empty device info set for network adapter device class. */
    HDEVINFO hDevInfoList = SetupDiCreateDeviceInfoList(&GUID_DEVCLASS_NET, hwndParent);
    if (hDevInfoList == INVALID_HANDLE_VALUE)
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiCreateDeviceInfoList failed", __FUNCTION__);
        return dwResult;
    }
 
    /* Get the device class name from GUID. */
    WCHAR szClassName[MAX_CLASS_NAME_LEN];
    if (!SetupDiClassNameFromGuid(&GUID_DEVCLASS_NET, szClassName, _countof(szClassName), NULL))
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiClassNameFromGuid failed", __FUNCTION__);
        goto cleanup_hDevInfoList;
    }
 
    /* Create a new device info element and add it to the device info set. */
    SP_DEVINFO_DATA devinfo_data = { .cbSize = sizeof(SP_DEVINFO_DATA) };
    if (!SetupDiCreateDeviceInfo(hDevInfoList, szClassName, &GUID_DEVCLASS_NET, szDeviceDescription,
                                 hwndParent, DICD_GENERATE_ID, &devinfo_data))
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiCreateDeviceInfo failed", __FUNCTION__);
        goto cleanup_hDevInfoList;
    }
 
    /* Set a device information element as the selected member of a device information set. */
    if (!SetupDiSetSelectedDevice(hDevInfoList, &devinfo_data))
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiSetSelectedDevice failed", __FUNCTION__);
        goto cleanup_hDevInfoList;
    }
 
    /* Set Plug&Play device hardware ID property. */
    if (!SetupDiSetDeviceRegistryProperty(hDevInfoList, &devinfo_data, SPDRP_HARDWAREID,
                                          (const BYTE *)szHwId,
                                          (DWORD)((wcslen(szHwId) + 1) * sizeof(WCHAR))))
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiSetDeviceRegistryProperty failed", __FUNCTION__);
        goto cleanup_hDevInfoList;
    }
 
    /* Register the device instance with the PnP Manager */
    if (!SetupDiCallClassInstaller(DIF_REGISTERDEVICE, hDevInfoList, &devinfo_data))
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiCallClassInstaller(DIF_REGISTERDEVICE) failed", __FUNCTION__);
        goto cleanup_hDevInfoList;
    }
 
    /* Install the device using DiInstallDevice()
     * We instruct the system to use the best driver in the driver store
     * by setting the drvinfo argument of DiInstallDevice as NULL. This
     * assumes a driver is already installed in the driver store.
     */
#ifdef HAVE_DIINSTALLDEVICE
    if (!DiInstallDevice(hwndParent, hDevInfoList, &devinfo_data, NULL, 0, pbRebootRequired))
#else
    /* mingw does not resolve DiInstallDevice, so load it at run time. */
    typedef BOOL(WINAPI * DiInstallDeviceFn)(HWND, HDEVINFO, SP_DEVINFO_DATA *, SP_DRVINFO_DATA *,
                                             DWORD, BOOL *);
    DiInstallDeviceFn installfn = find_function(L"newdev.dll", "DiInstallDevice", &libnewdev);
 
    if (!installfn)
    {
        dwResult = GetLastError();
        msg(M_NONFATAL | M_ERRNO, "%s: Failed to locate DiInstallDevice()", __FUNCTION__);
        goto cleanup_hDevInfoList;
    }
 
    if (!installfn(hwndParent, hDevInfoList, &devinfo_data, NULL, 0, pbRebootRequired))
#endif
    {
        dwResult = GetLastError();
        msg(M_NONFATAL | M_ERRNO, "%s: DiInstallDevice failed", __FUNCTION__);
        goto cleanup_remove_device;
    }
 
    /* Get network adapter ID from registry. Retry for max 30sec. */
    dwResult = get_net_adapter_guid(hDevInfoList, &devinfo_data, 30, pguidAdapter);
 
cleanup_remove_device:
    if (dwResult != ERROR_SUCCESS)
    {
        /* The adapter was installed. But, the adapter ID was unobtainable. Clean-up. */
        SP_REMOVEDEVICE_PARAMS removedevice_params = {
            .ClassInstallHeader = {
                .cbSize = sizeof(SP_CLASSINSTALL_HEADER),
                .InstallFunction = DIF_REMOVE,
            },
            .Scope = DI_REMOVEDEVICE_GLOBAL,
            .HwProfile = 0,
        };
 
        /* Set class installer parameters for DIF_REMOVE. */
        if (SetupDiSetClassInstallParams(hDevInfoList, &devinfo_data,
                                         &removedevice_params.ClassInstallHeader,
                                         sizeof(SP_REMOVEDEVICE_PARAMS)))
        {
            /* Call appropriate class installer. */
            if (SetupDiCallClassInstaller(DIF_REMOVE, hDevInfoList, &devinfo_data))
            {
                /* Check if a system reboot is required. */
                check_reboot(hDevInfoList, &devinfo_data, pbRebootRequired);
            }
            else
            {
                msg(M_NONFATAL | M_ERRNO, "%s: SetupDiCallClassInstaller(DIF_REMOVE) failed",
                    __FUNCTION__);
            }
        }
        else
        {
            msg(M_NONFATAL | M_ERRNO, "%s: SetupDiSetClassInstallParams failed", __FUNCTION__);
        }
    }
 
cleanup_hDevInfoList:
    if (libnewdev)
    {
        FreeLibrary(libnewdev);
    }
    SetupDiDestroyDeviceInfoList(hDevInfoList);
    return dwResult;
}
 
 
static DWORD
execute_on_first_adapter(_In_opt_ HWND hwndParent, _In_ LPCGUID pguidAdapter,
                         _In_ devop_func_t funcOperation, _Inout_ LPBOOL pbRebootRequired)
{
    DWORD dwResult;
 
    if (pguidAdapter == NULL)
    {
        return ERROR_BAD_ARGUMENTS;
    }
 
    /* Create a list of network devices. */
    HDEVINFO hDevInfoList = SetupDiGetClassDevsEx(&GUID_DEVCLASS_NET, NULL, hwndParent,
                                                  DIGCF_PRESENT, NULL, NULL, NULL);
    if (hDevInfoList == INVALID_HANDLE_VALUE)
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiGetClassDevsEx failed", __FUNCTION__);
        return dwResult;
    }
 
    /* Retrieve information associated with a device information set. */
    SP_DEVINFO_LIST_DETAIL_DATA devinfo_list_detail_data = { .cbSize = sizeof(
                                                                 SP_DEVINFO_LIST_DETAIL_DATA) };
    if (!SetupDiGetDeviceInfoListDetail(hDevInfoList, &devinfo_list_detail_data))
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiGetDeviceInfoListDetail failed", __FUNCTION__);
        goto cleanup_hDevInfoList;
    }
 
    /* Iterate. */
    for (DWORD dwIndex = 0;; dwIndex++)
    {
        /* Get the device from the list. */
        SP_DEVINFO_DATA devinfo_data = { .cbSize = sizeof(SP_DEVINFO_DATA) };
        if (!SetupDiEnumDeviceInfo(hDevInfoList, dwIndex, &devinfo_data))
        {
            if (GetLastError() == ERROR_NO_MORE_ITEMS)
            {
                LPOLESTR szAdapterId = NULL;
                StringFromIID((REFIID)pguidAdapter, &szAdapterId);
                msg(M_NONFATAL, "%s: Adapter %ls not found", __FUNCTION__, szAdapterId);
                CoTaskMemFree(szAdapterId);
                dwResult = ERROR_FILE_NOT_FOUND;
                goto cleanup_hDevInfoList;
            }
            else
            {
                /* Something is wrong with this device. Skip it. */
                msg(M_WARN | M_ERRNO, "%s: SetupDiEnumDeviceInfo(%u) failed", __FUNCTION__,
                    dwIndex);
                continue;
            }
        }
 
        /* Get adapter GUID. */
        GUID guidAdapter;
        dwResult = get_net_adapter_guid(hDevInfoList, &devinfo_data, 1, &guidAdapter);
        if (dwResult != ERROR_SUCCESS)
        {
            /* Something is wrong with this device. Skip it. */
            continue;
        }
 
        /* Compare GUIDs. */
        if (memcmp(pguidAdapter, &guidAdapter, sizeof(GUID)) == 0)
        {
            dwResult = funcOperation(hDevInfoList, &devinfo_data, pbRebootRequired);
            break;
        }
    }
 
cleanup_hDevInfoList:
    SetupDiDestroyDeviceInfoList(hDevInfoList);
    return dwResult;
}
 
 
DWORD
tap_delete_adapter(_In_opt_ HWND hwndParent, _In_ LPCGUID pguidAdapter,
                   _Inout_ LPBOOL pbRebootRequired)
{
    return execute_on_first_adapter(hwndParent, pguidAdapter, delete_device, pbRebootRequired);
}
 
 
DWORD
tap_enable_adapter(_In_opt_ HWND hwndParent, _In_ LPCGUID pguidAdapter, _In_ BOOL bEnable,
                   _Inout_ LPBOOL pbRebootRequired)
{
    return execute_on_first_adapter(hwndParent, pguidAdapter,
                                    bEnable ? enable_device : disable_device, pbRebootRequired);
}
 
static DWORD
ExecNetsh(PWSTR cmdline)
{
    DWORD exit_code;
    STARTUPINFOW si;
    PROCESS_INFORMATION pi;
    DWORD proc_flags = CREATE_NO_WINDOW | CREATE_UNICODE_ENVIRONMENT;
 
    ZeroMemory(&si, sizeof(si));
    ZeroMemory(&pi, sizeof(pi));
    si.cb = sizeof(si);
 
    WCHAR appName[MAX_PATH];
    WCHAR netsh_exe[] = L"\\netsh.exe";
    UINT sysdir_len = GetSystemDirectoryW(appName, _countof(appName));
    if (sysdir_len == 0)
    {
        wcscpy_s(appName, _countof(appName), L"C:\\Windows\\system32");
    }
    else if (sysdir_len + _countof(netsh_exe) > _countof(appName))
    {
        return ERROR_INSUFFICIENT_BUFFER;
    }
    wcscat_s(appName, _countof(appName), netsh_exe);
 
    if (CreateProcessW(appName, cmdline, NULL, NULL, FALSE, proc_flags, NULL, NULL, &si, &pi))
    {
        WaitForSingleObject(pi.hProcess, INFINITE);
        if (!GetExitCodeProcess(pi.hProcess, &exit_code))
        {
            exit_code = GetLastError();
        }
        CloseHandle(pi.hProcess);
        CloseHandle(pi.hThread);
    }
    else
    {
        exit_code = GetLastError();
    }
 
    return exit_code;
}
 
DWORD
tap_set_adapter_name(_In_ LPCGUID pguidAdapter, _In_ LPCWSTR szName, _In_ BOOL bSilent)
{
    DWORD dwResult;
    int msg_flag = bSilent ? M_WARN : M_NONFATAL;
    msg_flag |= M_ERRNO;
 
    if (pguidAdapter == NULL || szName == NULL)
    {
        return ERROR_BAD_ARGUMENTS;
    }
 
    /* Get the device class GUID as string. */
    LPOLESTR szDevClassNetId = NULL;
    StringFromIID((REFIID)&GUID_DEVCLASS_NET, &szDevClassNetId);
 
    /* Get the adapter GUID as string. */
    LPOLESTR szAdapterId = NULL;
    StringFromIID((REFIID)pguidAdapter, &szAdapterId);
 
    /* Render registry key path. */
    WCHAR szRegKey[ADAPTER_REGKEY_PATH_MAX];
    swprintf_s(szRegKey, _countof(szRegKey), szAdapterRegKeyPathTemplate, szDevClassNetId,
               szAdapterId);
 
    /* Open network adapter registry key. */
    HKEY hKey = NULL;
    dwResult = RegOpenKeyEx(HKEY_LOCAL_MACHINE, szRegKey, 0, KEY_QUERY_VALUE, &hKey);
    if (dwResult != ERROR_SUCCESS)
    {
        SetLastError(dwResult); /* MSDN does not mention RegOpenKeyEx() to set GetLastError(). But
                                   we do have an error code. Set last error manually. */
        msg(msg_flag, "%s: RegOpenKeyEx(HKLM, \"%ls\") failed", __FUNCTION__, szRegKey);
        goto cleanup_szAdapterId;
    }
 
    LPWSTR szOldName = NULL;
    dwResult = get_reg_string(hKey, L"Name", &szOldName);
    if (dwResult != ERROR_SUCCESS)
    {
        SetLastError(dwResult);
        msg(msg_flag, "%s: Error reading adapter name", __FUNCTION__);
        goto cleanup_hKey;
    }
 
    /* rename adapter via netsh call */
    const WCHAR *szFmt = L"netsh interface set interface name=\"%"
                         L"ls\" newname=\"%ls\"";
    size_t ncmdline = wcslen(szFmt) + wcslen(szOldName) + wcslen(szName) + 1;
    WCHAR *szCmdLine = malloc(ncmdline * sizeof(WCHAR));
    swprintf_s(szCmdLine, ncmdline, szFmt, szOldName, szName);
 
    free(szOldName);
 
    dwResult = ExecNetsh(szCmdLine);
    free(szCmdLine);
 
    if (dwResult != ERROR_SUCCESS)
    {
        SetLastError(dwResult);
        msg(msg_flag, "%s: Error renaming adapter", __FUNCTION__);
        goto cleanup_hKey;
    }
 
cleanup_hKey:
    RegCloseKey(hKey);
cleanup_szAdapterId:
    CoTaskMemFree(szAdapterId);
    CoTaskMemFree(szDevClassNetId);
    return dwResult;
}
 
 
DWORD
tap_list_adapters(_In_opt_ HWND hwndParent, _In_opt_ LPCWSTR szzHwIDs,
                  _Out_ struct tap_adapter_node **ppAdapter)
{
    DWORD dwResult;
 
    if (ppAdapter == NULL)
    {
        return ERROR_BAD_ARGUMENTS;
    }
 
    /* Create a list of network devices. */
    HDEVINFO hDevInfoList = SetupDiGetClassDevsEx(&GUID_DEVCLASS_NET, NULL, hwndParent,
                                                  DIGCF_PRESENT, NULL, NULL, NULL);
    if (hDevInfoList == INVALID_HANDLE_VALUE)
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiGetClassDevsEx failed", __FUNCTION__);
        return dwResult;
    }
 
    /* Retrieve information associated with a device information set. */
    SP_DEVINFO_LIST_DETAIL_DATA devinfo_list_detail_data = { .cbSize = sizeof(
                                                                 SP_DEVINFO_LIST_DETAIL_DATA) };
    if (!SetupDiGetDeviceInfoListDetail(hDevInfoList, &devinfo_list_detail_data))
    {
        dwResult = GetLastError();
        msg(M_NONFATAL, "%s: SetupDiGetDeviceInfoListDetail failed", __FUNCTION__);
        goto cleanup_hDevInfoList;
    }
 
    /* Get the device class GUID as string. */
    LPOLESTR szDevClassNetId = NULL;
    StringFromIID((REFIID)&GUID_DEVCLASS_NET, &szDevClassNetId);
 
    /* Iterate. */
    *ppAdapter = NULL;
    struct tap_adapter_node *pAdapterTail = NULL;
    for (DWORD dwIndex = 0;; dwIndex++)
    {
        /* Get the device from the list. */
        SP_DEVINFO_DATA devinfo_data = { .cbSize = sizeof(SP_DEVINFO_DATA) };
        if (!SetupDiEnumDeviceInfo(hDevInfoList, dwIndex, &devinfo_data))
        {
            if (GetLastError() == ERROR_NO_MORE_ITEMS)
            {
                break;
            }
            else
            {
                /* Something is wrong with this device. Skip it. */
                msg(M_WARN | M_ERRNO, "%s: SetupDiEnumDeviceInfo(%u) failed", __FUNCTION__,
                    dwIndex);
                continue;
            }
        }
 
        /* Get device hardware ID(s). */
        DWORD dwDataType = REG_NONE;
        LPWSTR szzDeviceHardwareIDs = NULL;
        dwResult = get_device_reg_property(hDevInfoList, &devinfo_data, SPDRP_HARDWAREID,
                                           &dwDataType, (LPVOID)&szzDeviceHardwareIDs);
        if (dwResult != ERROR_SUCCESS)
        {
            /* Something is wrong with this device. Skip it. */
            continue;
        }
 
        /* Check that hardware ID is REG_SZ/REG_MULTI_SZ, and optionally if it matches ours. */
        if (dwDataType == REG_SZ)
        {
            if (szzHwIDs && !wcszistr(szzHwIDs, szzDeviceHardwareIDs))
            {
                /* This is not our device. Skip it. */
                goto cleanup_szzDeviceHardwareIDs;
            }
        }
        else if (dwDataType == REG_MULTI_SZ)
        {
            if (szzHwIDs)
            {
                for (LPWSTR s = szzDeviceHardwareIDs;; s += wcslen(s) + 1)
                {
                    if (s[0] == 0)
                    {
                        /* This is not our device. Skip it. */
                        goto cleanup_szzDeviceHardwareIDs;
                    }
                    else if (wcszistr(szzHwIDs, s))
                    {
                        /* This is our device. */
                        break;
                    }
                }
            }
        }
        else
        {
            /* Unexpected hardware ID format. Skip device. */
            goto cleanup_szzDeviceHardwareIDs;
        }
 
        /* Get adapter GUID. */
        GUID guidAdapter;
        dwResult = get_net_adapter_guid(hDevInfoList, &devinfo_data, 1, &guidAdapter);
        if (dwResult != ERROR_SUCCESS)
        {
            /* Something is wrong with this device. Skip it. */
            goto cleanup_szzDeviceHardwareIDs;
        }
 
        /* Get the adapter GUID as string. */
        LPOLESTR szAdapterId = NULL;
        StringFromIID((REFIID)&guidAdapter, &szAdapterId);
 
        /* Render registry key path. */
        WCHAR szRegKey[ADAPTER_REGKEY_PATH_MAX];
        swprintf_s(szRegKey, _countof(szRegKey), szAdapterRegKeyPathTemplate, szDevClassNetId,
                   szAdapterId);
 
        /* Open network adapter registry key. */
        HKEY hKey = NULL;
        dwResult = RegOpenKeyEx(HKEY_LOCAL_MACHINE, szRegKey, 0, KEY_READ, &hKey);
        if (dwResult != ERROR_SUCCESS)
        {
            SetLastError(dwResult); /* MSDN does not mention RegOpenKeyEx() to set GetLastError().
                                       But we do have an error code. Set last error manually. */
            msg(M_WARN | M_ERRNO, "%s: RegOpenKeyEx(HKLM, \"%ls\") failed", __FUNCTION__, szRegKey);
            goto cleanup_szAdapterId;
        }
 
        /* Read adapter name. */
        LPWSTR szName = NULL;
        dwResult = get_reg_string(hKey, L"Name", &szName);
        if (dwResult != ERROR_SUCCESS)
        {
            SetLastError(dwResult);
            msg(M_WARN | M_ERRNO, "%s: Cannot determine %ls adapter name", __FUNCTION__,
                szAdapterId);
            goto cleanup_hKey;
        }
 
        /* Append to the list. */
        size_t hwid_size = (wcszlen(szzDeviceHardwareIDs) + 1) * sizeof(WCHAR);
        size_t name_size = (wcslen(szName) + 1) * sizeof(WCHAR);
        struct tap_adapter_node *node = (struct tap_adapter_node *)malloc(
            sizeof(struct tap_adapter_node) + hwid_size + name_size);
        if (node == NULL)
        {
            msg(M_FATAL, "%s: malloc(%u) failed", __FUNCTION__,
                sizeof(struct tap_adapter_node) + hwid_size + name_size);
            dwResult = ERROR_OUTOFMEMORY;
            goto cleanup_szName;
        }
 
        memcpy(&node->guid, &guidAdapter, sizeof(GUID));
        node->szzHardwareIDs = (LPWSTR)(node + 1);
        memcpy(node->szzHardwareIDs, szzDeviceHardwareIDs, hwid_size);
        node->szName = (LPWSTR)((LPBYTE)node->szzHardwareIDs + hwid_size);
        memcpy(node->szName, szName, name_size);
        node->pNext = NULL;
        if (pAdapterTail)
        {
            pAdapterTail->pNext = node;
            pAdapterTail = node;
        }
        else
        {
            *ppAdapter = pAdapterTail = node;
        }
 
cleanup_szName:
        free(szName);
cleanup_hKey:
        RegCloseKey(hKey);
cleanup_szAdapterId:
        CoTaskMemFree(szAdapterId);
cleanup_szzDeviceHardwareIDs:
        free(szzDeviceHardwareIDs);
    }
 
    dwResult = ERROR_SUCCESS;
 
    CoTaskMemFree(szDevClassNetId);
cleanup_hDevInfoList:
    SetupDiDestroyDeviceInfoList(hDevInfoList);
    return dwResult;
}
 
 
void
tap_free_adapter_list(_In_ struct tap_adapter_node *pAdapterList)
{
    /* Iterate over all nodes of the list. */
    while (pAdapterList)
    {
        struct tap_adapter_node *node = pAdapterList;
        pAdapterList = pAdapterList->pNext;
 
        /* Free the adapter node. */
        free(node);
    }
}