mirror of
https://github.com/KusakabeShi/EtherGuard-VPN.git
synced 2024-12-29 00:48:47 +01:00
483 lines
9.9 KiB
Go
483 lines
9.9 KiB
Go
/* SPDX-License-Identifier: GPL-2.0
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*
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* Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*/
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package main
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"golang.org/x/sys/windows"
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"golang.org/x/sys/windows/registry"
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"net"
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"sync"
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"syscall"
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"time"
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"unsafe"
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)
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/* Relies on the OpenVPN TAP-Windows driver (NDIS 6 version)
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*
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* https://github.com/OpenVPN/tap-windows
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*/
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type NativeTUN struct {
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fd windows.Handle
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rl sync.Mutex
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wl sync.Mutex
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ro *windows.Overlapped
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wo *windows.Overlapped
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events chan TUNEvent
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name string
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}
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const (
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METHOD_BUFFERED = 0
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ComponentID = "tap0901" // tap0801
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)
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func ctl_code(device_type, function, method, access uint32) uint32 {
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return (device_type << 16) | (access << 14) | (function << 2) | method
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}
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func TAP_CONTROL_CODE(request, method uint32) uint32 {
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return ctl_code(file_device_unknown, request, method, 0)
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}
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var (
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errIfceNameNotFound = errors.New("Failed to find the name of interface")
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TAP_IOCTL_GET_MAC = TAP_CONTROL_CODE(1, METHOD_BUFFERED)
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TAP_IOCTL_GET_VERSION = TAP_CONTROL_CODE(2, METHOD_BUFFERED)
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TAP_IOCTL_GET_MTU = TAP_CONTROL_CODE(3, METHOD_BUFFERED)
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TAP_IOCTL_GET_INFO = TAP_CONTROL_CODE(4, METHOD_BUFFERED)
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TAP_IOCTL_CONFIG_POINT_TO_POINT = TAP_CONTROL_CODE(5, METHOD_BUFFERED)
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TAP_IOCTL_SET_MEDIA_STATUS = TAP_CONTROL_CODE(6, METHOD_BUFFERED)
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TAP_IOCTL_CONFIG_DHCP_MASQ = TAP_CONTROL_CODE(7, METHOD_BUFFERED)
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TAP_IOCTL_GET_LOG_LINE = TAP_CONTROL_CODE(8, METHOD_BUFFERED)
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TAP_IOCTL_CONFIG_DHCP_SET_OPT = TAP_CONTROL_CODE(9, METHOD_BUFFERED)
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TAP_IOCTL_CONFIG_TUN = TAP_CONTROL_CODE(10, METHOD_BUFFERED)
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file_device_unknown = uint32(0x00000022)
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nCreateEvent,
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nResetEvent,
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nGetOverlappedResult uintptr
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)
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func init() {
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k32, err := windows.LoadLibrary("kernel32.dll")
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if err != nil {
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panic("LoadLibrary " + err.Error())
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}
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defer windows.FreeLibrary(k32)
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nCreateEvent = getProcAddr(k32, "CreateEventW")
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nResetEvent = getProcAddr(k32, "ResetEvent")
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nGetOverlappedResult = getProcAddr(k32, "GetOverlappedResult")
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}
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/* implementation of the read/write/closer interface */
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func getProcAddr(lib windows.Handle, name string) uintptr {
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addr, err := windows.GetProcAddress(lib, name)
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if err != nil {
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panic(name + " " + err.Error())
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}
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return addr
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}
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func resetEvent(h windows.Handle) error {
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r, _, err := syscall.Syscall(nResetEvent, 1, uintptr(h), 0, 0)
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if r == 0 {
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return err
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}
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return nil
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}
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func getOverlappedResult(h windows.Handle, overlapped *windows.Overlapped) (int, error) {
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var n int
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r, _, err := syscall.Syscall6(
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nGetOverlappedResult,
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4,
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uintptr(h),
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uintptr(unsafe.Pointer(overlapped)),
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uintptr(unsafe.Pointer(&n)), 1, 0, 0)
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if r == 0 {
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return n, err
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}
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return n, nil
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}
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func newOverlapped() (*windows.Overlapped, error) {
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var overlapped windows.Overlapped
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r, _, err := syscall.Syscall6(nCreateEvent, 4, 0, 1, 0, 0, 0, 0)
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if r == 0 {
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return nil, err
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}
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overlapped.HEvent = windows.Handle(r)
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return &overlapped, nil
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}
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func (f *NativeTUN) Events() chan TUNEvent {
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return f.events
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}
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func (f *NativeTUN) Close() error {
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close(f.events)
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err := windows.Close(f.fd)
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return err
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}
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func (f *NativeTUN) Write(b []byte) (int, error) {
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f.wl.Lock()
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defer f.wl.Unlock()
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if err := resetEvent(f.wo.HEvent); err != nil {
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return 0, err
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}
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var n uint32
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err := windows.WriteFile(f.fd, b, &n, f.wo)
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if err != nil && err != windows.ERROR_IO_PENDING {
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return int(n), err
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}
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return getOverlappedResult(f.fd, f.wo)
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}
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func (f *NativeTUN) Read(b []byte) (int, error) {
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f.rl.Lock()
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defer f.rl.Unlock()
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if err := resetEvent(f.ro.HEvent); err != nil {
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return 0, err
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}
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var done uint32
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err := windows.ReadFile(f.fd, b, &done, f.ro)
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if err != nil && err != windows.ERROR_IO_PENDING {
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return int(done), err
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}
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return getOverlappedResult(f.fd, f.ro)
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}
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func getdeviceid(
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targetComponentId string,
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targetDeviceName string,
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) (deviceid string, err error) {
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getName := func(instanceId string) (string, error) {
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path := fmt.Sprintf(
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`SYSTEM\CurrentControlSet\Control\Network\{4D36E972-E325-11CE-BFC1-08002BE10318}\%s\Connection`,
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instanceId,
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)
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key, err := registry.OpenKey(
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registry.LOCAL_MACHINE,
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path,
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registry.READ,
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)
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if err != nil {
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return "", err
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}
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defer key.Close()
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val, _, err := key.GetStringValue("Name")
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key.Close()
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return val, err
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}
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getInstanceId := func(keyName string) (string, string, error) {
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path := fmt.Sprintf(
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`SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}\%s`,
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keyName,
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)
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key, err := registry.OpenKey(
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registry.LOCAL_MACHINE,
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path,
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registry.READ,
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)
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if err != nil {
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return "", "", err
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}
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defer key.Close()
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componentId, _, err := key.GetStringValue("ComponentId")
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if err != nil {
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return "", "", err
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}
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instanceId, _, err := key.GetStringValue("NetCfgInstanceId")
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return componentId, instanceId, err
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}
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// find list of all network devices
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k, err := registry.OpenKey(
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registry.LOCAL_MACHINE,
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`SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}`,
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registry.READ,
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)
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if err != nil {
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return "", fmt.Errorf("Failed to open the adapter registry, TAP driver may be not installed, %v", err)
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}
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defer k.Close()
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keys, err := k.ReadSubKeyNames(-1)
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if err != nil {
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return "", err
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}
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// look for matching component id and name
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var componentFound bool
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for _, v := range keys {
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componentId, instanceId, err := getInstanceId(v)
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if err != nil || componentId != targetComponentId {
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continue
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}
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componentFound = true
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deviceName, err := getName(instanceId)
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if err != nil || deviceName != targetDeviceName {
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continue
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}
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return instanceId, nil
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}
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// provide a descriptive error message
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if componentFound {
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return "", fmt.Errorf("Unable to find tun/tap device with name = %s", targetDeviceName)
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}
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return "", fmt.Errorf(
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"Unable to find device in registry with ComponentId = %s, is tap-windows installed?",
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targetComponentId,
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)
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}
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// setStatus is used to bring up or bring down the interface
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func setStatus(fd windows.Handle, status bool) error {
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var code [4]byte
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if status {
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binary.LittleEndian.PutUint32(code[:], 1)
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}
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var bytesReturned uint32
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rdbbuf := make([]byte, windows.MAXIMUM_REPARSE_DATA_BUFFER_SIZE)
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return windows.DeviceIoControl(
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fd,
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TAP_IOCTL_SET_MEDIA_STATUS,
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&code[0],
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uint32(4),
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&rdbbuf[0],
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uint32(len(rdbbuf)),
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&bytesReturned,
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nil,
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)
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}
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/* When operating in TUN mode we must assign an ip address & subnet to the device.
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*
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*/
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func setTUN(fd windows.Handle, network string) error {
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var bytesReturned uint32
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rdbbuf := make([]byte, windows.MAXIMUM_REPARSE_DATA_BUFFER_SIZE)
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localIP, remoteNet, err := net.ParseCIDR(network)
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if err != nil {
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return fmt.Errorf("Failed to parse network CIDR in config, %v", err)
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}
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if localIP.To4() == nil {
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return fmt.Errorf("Provided network(%s) is not a valid IPv4 address", network)
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}
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var param [12]byte
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copy(param[0:4], localIP.To4())
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copy(param[4:8], remoteNet.IP.To4())
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copy(param[8:12], remoteNet.Mask)
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return windows.DeviceIoControl(
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fd,
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TAP_IOCTL_CONFIG_TUN,
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¶m[0],
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uint32(12),
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&rdbbuf[0],
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uint32(len(rdbbuf)),
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&bytesReturned,
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nil,
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)
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}
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func (tun *NativeTUN) MTU() (int, error) {
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var mtu [4]byte
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var bytesReturned uint32
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err := windows.DeviceIoControl(
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tun.fd,
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TAP_IOCTL_GET_MTU,
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&mtu[0],
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uint32(len(mtu)),
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&mtu[0],
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uint32(len(mtu)),
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&bytesReturned,
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nil,
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)
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val := binary.LittleEndian.Uint32(mtu[:])
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return int(val), err
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}
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func (tun *NativeTUN) Name() string {
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return tun.name
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}
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func CreateTUN(name string) (TUNDevice, error) {
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// find the device in registry.
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deviceid, err := getdeviceid(ComponentID, name)
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if err != nil {
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return nil, err
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}
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path := "\\\\.\\Global\\" + deviceid + ".tap"
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pathp, err := windows.UTF16PtrFromString(path)
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if err != nil {
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return nil, err
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}
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// create TUN device
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handle, err := windows.CreateFile(
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pathp,
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windows.GENERIC_READ|windows.GENERIC_WRITE,
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0,
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nil,
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windows.OPEN_EXISTING,
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windows.FILE_ATTRIBUTE_SYSTEM|windows.FILE_FLAG_OVERLAPPED,
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0,
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)
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if err != nil {
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return nil, err
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}
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ro, err := newOverlapped()
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if err != nil {
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windows.Close(handle)
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return nil, err
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}
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wo, err := newOverlapped()
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if err != nil {
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windows.Close(handle)
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return nil, err
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}
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tun := &NativeTUN{
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fd: handle,
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name: name,
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ro: ro,
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wo: wo,
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events: make(chan TUNEvent, 5),
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}
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// find addresses of interface
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// TODO: fix this hack, the question is how
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inter, err := net.InterfaceByName(name)
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if err != nil {
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windows.Close(handle)
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return nil, err
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}
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addrs, err := inter.Addrs()
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if err != nil {
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windows.Close(handle)
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return nil, err
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}
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var ip net.IP
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for _, addr := range addrs {
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ip = func() net.IP {
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switch v := addr.(type) {
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case *net.IPNet:
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return v.IP.To4()
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case *net.IPAddr:
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return v.IP.To4()
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}
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return nil
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}()
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if ip != nil {
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break
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}
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}
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if ip == nil {
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windows.Close(handle)
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return nil, errors.New("No IPv4 address found for interface")
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}
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// bring up device.
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if err := setStatus(handle, true); err != nil {
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windows.Close(handle)
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return nil, err
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}
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// set tun mode
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mask := ip.String() + "/0"
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if err := setTUN(handle, mask); err != nil {
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windows.Close(handle)
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return nil, err
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}
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// start listener
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go func(native *NativeTUN, ifname string) {
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// TODO: Fix this very niave implementation
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var (
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statusUp bool
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statusMTU int
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)
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for ; ; time.Sleep(time.Second) {
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intr, err := net.InterfaceByName(name)
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if err != nil {
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// TODO: handle
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return
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}
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// Up / Down event
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up := (intr.Flags & net.FlagUp) != 0
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if up != statusUp && up {
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native.events <- TUNEventUp
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}
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if up != statusUp && !up {
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native.events <- TUNEventDown
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}
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statusUp = up
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// MTU changes
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if intr.MTU != statusMTU {
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native.events <- TUNEventMTUUpdate
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}
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statusMTU = intr.MTU
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}
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}(tun, name)
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return tun, nil
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}
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