wireguard-go/tun/tun_windows.go

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/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2018-2019 WireGuard LLC. All Rights Reserved.
*/
package tun
//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output ztun_windows.go tun_windows.go
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import (
"errors"
"fmt"
"os"
"strings"
"syscall"
"time"
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"unsafe"
"git.zx2c4.com/wireguard-go/setupapi"
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"golang.org/x/sys/windows"
"golang.org/x/sys/windows/registry"
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)
const (
TUN_MAX_PACKET_SIZE = 1600
TUN_MAX_PACKET_EXCHANGE = 256 // Number of packets that can be exchanged at a time
TUN_EXCHANGE_BUFFER_SIZE = 410632
)
const (
TUN_SIGNAL_DATA_AVAIL = 0
TUN_SIGNAL_CLOSE = 1
TUN_SIGNAL_MAX = 2
)
var deviceClassNetGUID = windows.GUID{0x4d36e972, 0xe325, 0x11ce, [8]byte{0xbf, 0xc1, 0x08, 0x00, 0x2b, 0xe1, 0x03, 0x18}}
const TUN_HWID = "Wintun"
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type tunPacket struct {
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size uint32
data [TUN_MAX_PACKET_SIZE]byte
}
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type tunRWQueue struct {
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numPackets uint32
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packets [TUN_MAX_PACKET_EXCHANGE]tunPacket
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left uint32
}
type nativeTun struct {
ifid *windows.GUID
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tunName string
signalName *uint16
tunFile *os.File
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wrBuff tunRWQueue
rdBuff tunRWQueue
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signals [TUN_SIGNAL_MAX]windows.Handle
rdNextPacket uint32
events chan TUNEvent
errors chan error
}
func CreateTUN(ifname string) (TUNDevice, error) {
// Does an interface with this name already exist?
ifid, err := getInterface(ifname, 0)
if ifid == nil || err != nil {
// Interface does not exist or an error occured. Create one.
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ifid, _, err = createInterface("WireGuard Tunnel Adapter", 0)
if err != nil {
return nil, err
}
// Set interface name. (Ignore errors.)
setInterfaceName(ifid, ifname)
}
ifidStr := guidToString(ifid)
signalNameUTF16, err := windows.UTF16PtrFromString(fmt.Sprintf("Global\\WINTUN_EVENT_%s", ifidStr))
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if err != nil {
deleteInterface(ifid, 0)
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return nil, err
}
// Create instance.
tun := &nativeTun{
ifid: ifid,
tunName: fmt.Sprintf("\\\\.\\Global\\WINTUN_DEVICE_%s", ifidStr),
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signalName: signalNameUTF16,
events: make(chan TUNEvent, 10),
errors: make(chan error, 1),
}
// Create close event.
tun.signals[TUN_SIGNAL_CLOSE], err = windows.CreateEvent(nil, 1 /*TRUE*/, 0 /*FALSE*/, nil)
if err != nil {
deleteInterface(ifid, 0)
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return nil, err
}
return tun, nil
}
func (tun *nativeTun) openTUN() error {
for {
// Open interface data pipe.
// Data pipe must be opened first, as the interface data available event is created when somebody actually connects to the data pipe.
file, err := os.OpenFile(tun.tunName, os.O_RDWR|os.O_SYNC, 0600)
if err != nil {
// After examining possible error conditions, many arose that were only temporary: windows.ERROR_FILE_NOT_FOUND, "read <filename> closed", etc.
// To simplify, we will enter a retry-loop on _any_ error until session is closed by user.
switch evt, e := windows.WaitForSingleObject(tun.signals[TUN_SIGNAL_CLOSE], 1000); evt {
case windows.WAIT_OBJECT_0, windows.WAIT_ABANDONED:
return errors.New("TUN closed")
case windows.WAIT_TIMEOUT:
continue
default:
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return errors.New("Unexpected result from WaitForSingleObject: " + e.Error())
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}
}
// Open interface data available event.
event, err := windows.OpenEvent(windows.SYNCHRONIZE, false, tun.signalName)
if err != nil {
file.Close()
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return errors.New("Opening interface data ready event failed: " + err.Error())
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}
tun.tunFile = file
tun.signals[TUN_SIGNAL_DATA_AVAIL] = event
return nil
}
}
func (tun *nativeTun) closeTUN() (err error) {
if tun.signals[TUN_SIGNAL_DATA_AVAIL] != 0 {
// Close interface data ready event.
e := windows.CloseHandle(tun.signals[TUN_SIGNAL_DATA_AVAIL])
if err != nil {
err = e
}
tun.signals[TUN_SIGNAL_DATA_AVAIL] = 0
}
if tun.tunFile != nil {
// Close interface data pipe.
e := tun.tunFile.Close()
if err != nil {
err = e
}
tun.tunFile = nil
}
return
}
func (tun *nativeTun) Name() (string, error) {
return getInterfaceName(tun.ifid)
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}
func (tun *nativeTun) File() *os.File {
return nil
}
func (tun *nativeTun) Events() chan TUNEvent {
return tun.events
}
func (tun *nativeTun) Close() error {
windows.SetEvent(tun.signals[TUN_SIGNAL_CLOSE])
err := windows.CloseHandle(tun.signals[TUN_SIGNAL_CLOSE])
e := tun.closeTUN()
if err == nil {
err = e
}
if tun.events != nil {
close(tun.events)
}
_, _, e = deleteInterface(tun.ifid, 0)
if err == nil {
err = e
}
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return err
}
func (tun *nativeTun) MTU() (int, error) {
return 1500, nil
}
func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
select {
case err := <-tun.errors:
return 0, err
default:
for {
if tun.rdNextPacket < tun.rdBuff.numPackets {
// Get packet from the queue.
tunPacket := &tun.rdBuff.packets[tun.rdNextPacket]
tun.rdNextPacket++
if TUN_MAX_PACKET_SIZE < tunPacket.size {
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// Invalid packet size.
continue
}
// Copy data.
copy(buff[offset:], tunPacket.data[:tunPacket.size])
return int(tunPacket.size), nil
}
if tun.signals[TUN_SIGNAL_DATA_AVAIL] == 0 {
// Data pipe and interface data available event are not open (yet).
err := tun.openTUN()
if err != nil {
return 0, err
}
}
if tun.rdBuff.numPackets < TUN_MAX_PACKET_EXCHANGE || tun.rdBuff.left == 0 {
// Buffer was not full. Wait for the interface data or user close.
r, err := windows.WaitForMultipleObjects(tun.signals[:], false, windows.INFINITE)
if err != nil {
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return 0, errors.New("Waiting for data failed: " + err.Error())
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}
switch r {
case windows.WAIT_OBJECT_0 + TUN_SIGNAL_DATA_AVAIL:
// Data is available.
case windows.WAIT_ABANDONED + TUN_SIGNAL_DATA_AVAIL:
// TUN stopped. Reopen it.
tun.closeTUN()
continue
case windows.WAIT_OBJECT_0 + TUN_SIGNAL_CLOSE, windows.WAIT_ABANDONED + TUN_SIGNAL_CLOSE:
return 0, errors.New("TUN closed")
case windows.WAIT_TIMEOUT:
// Congratulations, we reached infinity. Let's do it again! :)
continue
default:
return 0, errors.New("unexpected result from WaitForMultipleObjects")
}
}
// Fill queue.
data := (*[TUN_EXCHANGE_BUFFER_SIZE]byte)(unsafe.Pointer(&tun.rdBuff))
n, err := tun.tunFile.Read(data[:])
tun.rdNextPacket = 0
if n != TUN_EXCHANGE_BUFFER_SIZE || err != nil {
// TUN interface stopped, returned incomplete data, etc.
// Retry.
tun.rdBuff.numPackets = 0
tun.closeTUN()
continue
}
}
}
}
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// Note: flush() and putTunPacket() assume the caller comes only from a single thread; there's no locking.
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func (tun *nativeTun) flush() error {
// Flush write buffer.
data := (*[TUN_EXCHANGE_BUFFER_SIZE]byte)(unsafe.Pointer(&tun.wrBuff))
n, err := tun.tunFile.Write(data[:])
tun.wrBuff.numPackets = 0
if err != nil {
return err
}
if n != TUN_EXCHANGE_BUFFER_SIZE {
return fmt.Errorf("%d byte(s) written, %d byte(s) expected", n, TUN_EXCHANGE_BUFFER_SIZE)
}
return nil
}
func (tun *nativeTun) putTunPacket(buff []byte) error {
size := len(buff)
if size == 0 {
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return errors.New("Empty packet")
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}
if size > TUN_MAX_PACKET_SIZE {
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return errors.New("Packet too big")
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}
if tun.wrBuff.numPackets >= TUN_MAX_PACKET_EXCHANGE {
// Queue is full -> flush first.
err := tun.flush()
if err != nil {
return err
}
}
// Push packet to the buffer.
tunPacket := &tun.wrBuff.packets[tun.wrBuff.numPackets]
tunPacket.size = uint32(size)
copy(tunPacket.data[:size], buff)
tun.wrBuff.numPackets++
return nil
}
func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {
err := tun.putTunPacket(buff[offset:])
if err != nil {
return 0, err
}
// Flush write buffer.
return len(buff) - offset, tun.flush()
}
//
// getInterface finds interface ID by name.
//
// hwndParent is a handle to the top-level window to use for any user
// interface that is related to non-device-specific actions (such as a select-
// device dialog box that uses the global class driver list). This handle is
// optional and can be 0. If a specific top-level window is not required, set
// hwndParent to 0.
//
// Function returns interface ID when the interface was found, or nil
// otherwise.
//
func getInterface(ifname string, hwndParent uintptr) (*windows.GUID, error) {
// Create a list of network devices.
devInfoList, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", hwndParent, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
if err != nil {
return nil, err
}
defer devInfoList.Close()
// Retrieve information associated with a device information set.
// TODO: Is this really necessary?
_, err = devInfoList.GetDeviceInfoListDetail()
if err != nil {
return nil, err
}
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// TODO: If we're certain we want case-insensitive name comparison, please document the rationale.
ifname = strings.ToLower(ifname)
// Iterate.
for index := 0; ; index++ {
// Get the device from the list.
deviceData, err := devInfoList.EnumDeviceInfo(index)
if err != nil {
if errWin, ok := err.(syscall.Errno); ok && errWin == 259 /*ERROR_NO_MORE_ITEMS*/ {
break
}
// Something is wrong with this device. Skip it.
continue
}
// Get interface ID.
ifid, err := getInterfaceId(devInfoList, deviceData, 1)
if err != nil {
// Something is wrong with this device. Skip it.
continue
}
// Get interface name.
ifname2, err := getInterfaceName(ifid)
if err != nil {
// Something is wrong with this device. Skip it.
continue
}
if ifname == strings.ToLower(ifname2) {
// Interface name found.
return ifid, nil
}
}
return nil, nil
}
//
// createInterface creates a TUN interface.
//
// description is a string that supplies the text description of the device.
// Description is optional and can be "".
//
// hwndParent is a handle to the top-level window to use for any user
// interface that is related to non-device-specific actions (such as a select-
// device dialog box that uses the global class driver list). This handle is
// optional and can be 0. If a specific top-level window is not required, set
// hwndParent to 0.
//
// Function returns the network interface ID and a flag if reboot is required.
//
func createInterface(description string, hwndParent uintptr) (*windows.GUID, bool, error) {
// Create an empty device info set for network adapter device class.
devInfoList, err := setupapi.SetupDiCreateDeviceInfoListEx(&deviceClassNetGUID, hwndParent, "")
if err != nil {
return nil, false, err
}
// Get the device class name from GUID.
className, err := setupapi.SetupDiClassNameFromGuidEx(&deviceClassNetGUID, "")
if err != nil {
return nil, false, err
}
// Create a new device info element and add it to the device info set.
deviceData, err := devInfoList.CreateDeviceInfo(className, &deviceClassNetGUID, description, hwndParent, setupapi.DICD_GENERATE_ID)
if err != nil {
return nil, false, err
}
// Set a device information element as the selected member of a device information set.
err = devInfoList.SetSelectedDevice(deviceData)
if err != nil {
return nil, false, err
}
// Set Plug&Play device hardware ID property.
hwid, err := syscall.UTF16FromString(TUN_HWID)
if err != nil {
return nil, false, err
}
err = devInfoList.SetDeviceRegistryProperty(deviceData, setupapi.SPDRP_HARDWAREID, setupapi.UTF16ToBuf(append(hwid, 0)))
if err != nil {
return nil, false, err
}
// Search for the driver.
const driverType = setupapi.SPDIT_CLASSDRIVER
err = devInfoList.BuildDriverInfoList(deviceData, driverType)
if err != nil {
return nil, false, err
}
defer devInfoList.DestroyDriverInfoList(deviceData, driverType)
driverDate := windows.Filetime{}
driverVersion := uint64(0)
for index := 0; ; index++ {
// Get a driver from the list.
driverData, err := devInfoList.EnumDriverInfo(deviceData, driverType, index)
if err != nil {
if errWin, ok := err.(syscall.Errno); ok && errWin == 259 /*ERROR_NO_MORE_ITEMS*/ {
break
}
// Something is wrong with this driver. Skip it.
continue
}
// Check the driver version first, since the check is trivial and will save us iterating over hardware IDs for any driver versioned prior our best match.
if driverData.IsNewer(driverDate, driverVersion) {
// Get driver info details.
driverDetailData, err := devInfoList.GetDriverInfoDetail(deviceData, driverData)
if err != nil {
// Something is wrong with this driver. Skip it.
continue
}
if driverDetailData.IsCompatible(TUN_HWID) {
// Matching hardware ID found. Select the driver.
err := devInfoList.SetSelectedDriver(deviceData, driverData)
if err != nil {
// Something is wrong with this driver. Skip it.
continue
}
driverDate = driverData.DriverDate
driverVersion = driverData.DriverVersion
}
}
}
if driverVersion == 0 {
return nil, false, fmt.Errorf("No driver for device \"%v\" installed", TUN_HWID)
}
// Call appropriate class installer.
err = devInfoList.CallClassInstaller(setupapi.DIF_REGISTERDEVICE, deviceData)
if err != nil {
return nil, false, err
}
// Register device co-installers if any.
devInfoList.CallClassInstaller(setupapi.DIF_REGISTER_COINSTALLERS, deviceData)
// Install interfaces if any.
devInfoList.CallClassInstaller(setupapi.DIF_INSTALLINTERFACES, deviceData)
var ifid *windows.GUID
var rebootRequired bool
// Install the device.
err = devInfoList.CallClassInstaller(setupapi.DIF_INSTALLDEVICE, deviceData)
if err == nil {
// Check if a system reboot is required. (Ignore errors)
if ret, _ := checkReboot(devInfoList, deviceData); ret {
rebootRequired = true
}
// Get network interface ID from registry. Retry for max 30sec.
ifid, err = getInterfaceId(devInfoList, deviceData, 30)
}
if err == nil {
return ifid, rebootRequired, nil
}
// The interface failed to install, or the interface ID was unobtainable. Clean-up.
removeDeviceParams := setupapi.SP_REMOVEDEVICE_PARAMS{
ClassInstallHeader: setupapi.SP_CLASSINSTALL_HEADER{
InstallFunction: setupapi.DIF_REMOVE,
},
Scope: setupapi.DI_REMOVEDEVICE_GLOBAL,
}
removeDeviceParams.ClassInstallHeader.Size = uint32(unsafe.Sizeof(removeDeviceParams.ClassInstallHeader))
// Set class installer parameters for DIF_REMOVE.
if devInfoList.SetClassInstallParams(deviceData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams))) == nil {
// Call appropriate class installer.
if devInfoList.CallClassInstaller(setupapi.DIF_REMOVE, deviceData) == nil {
// Check if a system reboot is required. (Ignore errors)
if ret, _ := checkReboot(devInfoList, deviceData); ret {
rebootRequired = true
}
}
}
return nil, false, err
}
//
// deleteInterface deletes a TUN interface.
//
// hwndParent is a handle to the top-level window to use for any user
// interface that is related to non-device-specific actions (such as a select-
// device dialog box that uses the global class driver list). This handle is
// optional and can be 0. If a specific top-level window is not required, set
// hwndParent to 0.
//
// Function returns true if the interface was found and deleted and a flag if
// reboot is required.
//
func deleteInterface(ifid *windows.GUID, hwndParent uintptr) (bool, bool, error) {
// Create a list of network devices.
devInfoList, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", hwndParent, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
if err != nil {
return false, false, err
}
defer devInfoList.Close()
// Retrieve information associated with a device information set.
// TODO: Is this really necessary?
_, err = devInfoList.GetDeviceInfoListDetail()
if err != nil {
return false, false, err
}
// Iterate.
for index := 0; ; index++ {
// Get the device from the list.
deviceData, err := devInfoList.EnumDeviceInfo(index)
if err != nil {
if errWin, ok := err.(syscall.Errno); ok && errWin == 259 /*ERROR_NO_MORE_ITEMS*/ {
break
}
// Something is wrong with this device. Skip it.
continue
}
// Get interface ID.
ifid2, err := getInterfaceId(devInfoList, deviceData, 1)
if err != nil {
// Something is wrong with this device. Skip it.
continue
}
if ifid == ifid2 {
// Remove the device.
removeDeviceParams := setupapi.SP_REMOVEDEVICE_PARAMS{
ClassInstallHeader: setupapi.SP_CLASSINSTALL_HEADER{
InstallFunction: setupapi.DIF_REMOVE,
},
Scope: setupapi.DI_REMOVEDEVICE_GLOBAL,
}
removeDeviceParams.ClassInstallHeader.Size = uint32(unsafe.Sizeof(removeDeviceParams.ClassInstallHeader))
// Set class installer parameters for DIF_REMOVE.
err = devInfoList.SetClassInstallParams(deviceData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams)))
if err != nil {
return false, false, err
}
// Call appropriate class installer.
err = devInfoList.CallClassInstaller(setupapi.DIF_REMOVE, deviceData)
if err != nil {
return false, false, err
}
// Check if a system reboot is required. (Ignore errors)
if ret, _ := checkReboot(devInfoList, deviceData); ret {
return true, true, nil
}
return true, false, nil
}
}
return false, false, nil
}
///
/// checkReboot checks device install parameters if a system reboot is required.
///
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func checkReboot(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.SP_DEVINFO_DATA) (bool, error) {
devInstallParams, err := deviceInfoSet.GetDeviceInstallParams(deviceInfoData)
if err != nil {
return false, err
}
if (devInstallParams.Flags & (setupapi.DI_NEEDREBOOT | setupapi.DI_NEEDRESTART)) != 0 {
return true, nil
}
return false, nil
}
// getInterfaceId returns network interface ID.
//
// After the device is created, it might take some time before the registry
// key is populated. numAttempts parameter specifies the number of attempts
// to read NetCfgInstanceId value from registry. A 1sec sleep is inserted
// between retry attempts.
//
// Function returns the network interface ID.
//
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func getInterfaceId(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.SP_DEVINFO_DATA, numAttempts int) (*windows.GUID, error) {
if numAttempts < 1 {
return nil, fmt.Errorf("Invalid numAttempts (expected: >=1, provided: %v)", numAttempts)
}
// Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\<class>\<id> registry key.
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key, err := deviceInfoSet.OpenDevRegKey(deviceInfoData, setupapi.DICS_FLAG_GLOBAL, 0, setupapi.DIREG_DRV, registry.READ)
if err != nil {
return nil, errors.New("Device-specific registry key open failed: " + err.Error())
}
defer key.Close()
for {
// Query the NetCfgInstanceId value. Using get_reg_string() right on might clutter the output with error messages while the registry is still being populated.
_, _, err = key.GetValue("NetCfgInstanceId", nil)
if err != nil {
if errWin, ok := err.(syscall.Errno); ok && errWin == windows.ERROR_FILE_NOT_FOUND {
numAttempts--
if numAttempts > 0 {
// Wait and retry.
// TODO: Wait for a cancellable event instead.
time.Sleep(1000 * time.Millisecond)
continue
}
}
return nil, errors.New("RegQueryValueEx(\"NetCfgInstanceId\") failed: " + err.Error())
}
// Read the NetCfgInstanceId value now.
value, err := getRegStringValue(key, "NetCfgInstanceId")
if err != nil {
return nil, errors.New("RegQueryStringValue(\"NetCfgInstanceId\") failed: " + err.Error())
}
// Convert to windows.GUID.
ifid, err := stringToGUID(value)
if err != nil {
return nil, fmt.Errorf("NetCfgInstanceId registry value is not a GUID (expected: \"{...}\", provided: \"%v\")", value)
}
return ifid, err
}
}
//
// getInterfaceName returns network interface name.
//
func getInterfaceName(ifid *windows.GUID) (string, error) {
// Open network interface registry key.
key, err := registry.OpenKey(registry.LOCAL_MACHINE, fmt.Sprintf("SYSTEM\\CurrentControlSet\\Control\\Network\\%v\\%v\\Connection", guidToString(&deviceClassNetGUID), guidToString(ifid)), registry.QUERY_VALUE)
if err != nil {
return "", errors.New("Network-specific registry key open failed: " + err.Error())
}
defer key.Close()
// Get the interface name.
return getRegStringValue(key, "Name")
}
//
// setInterfaceName sets network interface name.
//
func setInterfaceName(ifid *windows.GUID, ifname string) error {
// Open network interface registry key.
key, err := registry.OpenKey(registry.LOCAL_MACHINE, fmt.Sprintf("SYSTEM\\CurrentControlSet\\Control\\Network\\%v\\%v\\Connection", guidToString(&deviceClassNetGUID), guidToString(ifid)), registry.SET_VALUE)
if err != nil {
return errors.New("Network-specific registry key open failed: " + err.Error())
}
defer key.Close()
// Set the interface name.
return key.SetStringValue("Name", ifname)
}
//sys clsidFromString(lpsz *uint16, pclsid *windows.GUID) (hr int32) = ole32.CLSIDFromString
//
// stringToGUID parses "{XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}" string to GUID.
//
func stringToGUID(str string) (*windows.GUID, error) {
strUTF16, err := syscall.UTF16PtrFromString(str)
if err != nil {
return nil, err
}
guid := &windows.GUID{}
hr := clsidFromString(strUTF16, guid)
if hr < 0 {
return nil, syscall.Errno(hr)
}
return guid, nil
}
//
// guidToString function converts GUID to string
// "{XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}".
//
// The resulting string is uppercase.
//
func guidToString(guid *windows.GUID) string {
return fmt.Sprintf("{%06X-%04X-%04X-%04X-%012X}", guid.Data1, guid.Data2, guid.Data3, guid.Data4[:2], guid.Data4[2:])
}
//
// getRegStringValue function reads a string value from registry.
//
// If the value type is REG_EXPAND_SZ the environment variables are expanded.
// Should expanding fail, original string value and nil error are returned.
//
func getRegStringValue(key registry.Key, name string) (string, error) {
// Read string value.
value, valueType, err := key.GetStringValue(name)
if err != nil {
return "", err
}
if valueType != registry.EXPAND_SZ {
// Value does not require expansion.
return value, nil
}
valueExp, err := registry.ExpandString(value)
if err != nil {
// Expanding failed: return original sting value.
return value, nil
}
// Return expanded value.
return valueExp, nil
}