mirror of
https://git.zx2c4.com/wireguard-go
synced 2024-11-15 09:15:14 +01:00
359 lines
8.8 KiB
Go
359 lines
8.8 KiB
Go
/* SPDX-License-Identifier: MIT
|
|
*
|
|
* Copyright (C) 2018-2019 WireGuard LLC. All Rights Reserved.
|
|
*/
|
|
|
|
package tun
|
|
|
|
import (
|
|
"errors"
|
|
"os"
|
|
"sync"
|
|
"syscall"
|
|
"time"
|
|
"unsafe"
|
|
|
|
"golang.org/x/sys/windows"
|
|
"golang.zx2c4.com/wireguard/tun/wintun"
|
|
)
|
|
|
|
const (
|
|
packetExchangeMax uint32 = 256 // Number of packets that may be written at a time
|
|
packetExchangeAlignment uint32 = 16 // Number of bytes packets are aligned to in exchange buffers
|
|
packetSizeMax uint32 = 0xf000 - packetExchangeAlignment // Maximum packet size
|
|
packetExchangeSize uint32 = 0x100000 // Exchange buffer size (defaults to 1MiB)
|
|
retryRate = 4 // Number of retries per second to reopen device pipe
|
|
retryTimeout = 5 // Number of seconds to tolerate adapter unavailable
|
|
)
|
|
|
|
type exchgBufRead struct {
|
|
data [packetExchangeSize]byte
|
|
offset uint32
|
|
avail uint32
|
|
}
|
|
|
|
type exchgBufWrite struct {
|
|
data [packetExchangeSize]byte
|
|
offset uint32
|
|
packetNum uint32
|
|
}
|
|
|
|
type NativeTun struct {
|
|
wt *wintun.Wintun
|
|
tunName *uint16
|
|
tunFile windows.Handle
|
|
tunLock sync.Mutex
|
|
close bool
|
|
rdBuff *exchgBufRead
|
|
wrBuff *exchgBufWrite
|
|
rdEvent windows.Handle
|
|
wrEvent windows.Handle
|
|
events chan TUNEvent
|
|
errors chan error
|
|
forcedMtu int
|
|
}
|
|
|
|
//sys getOverlappedResult(handle windows.Handle, overlapped *windows.Overlapped, done *uint32, wait bool) (err error) = kernel32.GetOverlappedResult
|
|
|
|
func packetAlign(size uint32) uint32 {
|
|
return (size + (packetExchangeAlignment - 1)) &^ (packetExchangeAlignment - 1)
|
|
}
|
|
|
|
//
|
|
// CreateTUN creates a Wintun adapter with the given name. Should a Wintun
|
|
// adapter with the same name exist, it is reused.
|
|
//
|
|
func CreateTUN(ifname string) (TUNDevice, error) {
|
|
// Does an interface with this name already exist?
|
|
wt, err := wintun.GetInterface(ifname, 0)
|
|
if wt == nil {
|
|
// Interface does not exist or an error occured. Create one.
|
|
wt, _, err = wintun.CreateInterface("WireGuard Tunnel Adapter", 0)
|
|
if err != nil {
|
|
return nil, errors.New("Creating Wintun adapter failed: " + err.Error())
|
|
}
|
|
} else if err != nil {
|
|
// Foreign interface with the same name found.
|
|
// We could create a Wintun interface under a temporary name. But, should our
|
|
// proces die without deleting this interface first, the interface would remain
|
|
// orphaned.
|
|
return nil, err
|
|
}
|
|
|
|
err = wt.SetInterfaceName(ifname)
|
|
if err != nil {
|
|
wt.DeleteInterface(0)
|
|
return nil, errors.New("Setting interface name failed: " + err.Error())
|
|
}
|
|
|
|
err = wt.FlushInterface()
|
|
if err != nil {
|
|
wt.DeleteInterface(0)
|
|
return nil, errors.New("Flushing interface failed: " + err.Error())
|
|
}
|
|
|
|
tunNameUTF16, err := windows.UTF16PtrFromString(wt.DataFileName())
|
|
if err != nil {
|
|
wt.DeleteInterface(0)
|
|
return nil, err
|
|
}
|
|
|
|
rde, err := windows.CreateEvent(nil, 1 /*TRUE*/, 0 /*FALSE*/, nil)
|
|
if err != nil {
|
|
wt.DeleteInterface(0)
|
|
return nil, err
|
|
}
|
|
wre, err := windows.CreateEvent(nil, 1 /*TRUE*/, 0 /*FALSE*/, nil)
|
|
if err != nil {
|
|
windows.CloseHandle(rde)
|
|
wt.DeleteInterface(0)
|
|
return nil, err
|
|
}
|
|
|
|
return &NativeTun{
|
|
wt: wt,
|
|
tunName: tunNameUTF16,
|
|
tunFile: windows.InvalidHandle,
|
|
rdBuff: &exchgBufRead{},
|
|
wrBuff: &exchgBufWrite{},
|
|
rdEvent: rde,
|
|
wrEvent: wre,
|
|
events: make(chan TUNEvent, 10),
|
|
errors: make(chan error, 1),
|
|
forcedMtu: 1500,
|
|
}, nil
|
|
}
|
|
|
|
func (tun *NativeTun) openTUN() error {
|
|
retries := retryTimeout * retryRate
|
|
for {
|
|
if tun.close {
|
|
return errors.New("Cancelled")
|
|
}
|
|
|
|
file, err := windows.CreateFile(tun.tunName, windows.GENERIC_READ|windows.GENERIC_WRITE, 0, nil, windows.OPEN_EXISTING, windows.FILE_ATTRIBUTE_NORMAL|windows.FILE_FLAG_OVERLAPPED|windows.FILE_FLAG_NO_BUFFERING, 0)
|
|
if err != nil {
|
|
if retries > 0 {
|
|
time.Sleep(time.Second / retryRate)
|
|
retries--
|
|
continue
|
|
}
|
|
return err
|
|
}
|
|
|
|
tun.tunFile = file
|
|
return nil
|
|
}
|
|
}
|
|
|
|
func (tun *NativeTun) closeTUN() (err error) {
|
|
if tun.tunFile != windows.InvalidHandle {
|
|
tun.tunLock.Lock()
|
|
defer tun.tunLock.Unlock()
|
|
if tun.tunFile == windows.InvalidHandle {
|
|
return
|
|
}
|
|
t := tun.tunFile
|
|
tun.tunFile = windows.InvalidHandle
|
|
err = windows.CloseHandle(t)
|
|
}
|
|
return
|
|
}
|
|
|
|
func (tun *NativeTun) getTUN() (windows.Handle, error) {
|
|
if tun.tunFile == windows.InvalidHandle {
|
|
tun.tunLock.Lock()
|
|
defer tun.tunLock.Unlock()
|
|
if tun.tunFile != windows.InvalidHandle {
|
|
return tun.tunFile, nil
|
|
}
|
|
err := tun.openTUN()
|
|
if err != nil {
|
|
return windows.InvalidHandle, err
|
|
}
|
|
}
|
|
return tun.tunFile, nil
|
|
}
|
|
|
|
func (tun *NativeTun) isIOCancelled(err error) bool {
|
|
// Read&WriteFile() return the same ERROR_OPERATION_ABORTED if we close the handle
|
|
// or the TUN device is put down. We need a "close" flag to distinguish.
|
|
en, ok := err.(syscall.Errno)
|
|
if tun.close && ok && en == windows.ERROR_OPERATION_ABORTED {
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (tun *NativeTun) Name() (string, error) {
|
|
return tun.wt.GetInterfaceName()
|
|
}
|
|
|
|
func (tun *NativeTun) File() *os.File {
|
|
return nil
|
|
}
|
|
|
|
func (tun *NativeTun) Events() chan TUNEvent {
|
|
return tun.events
|
|
}
|
|
|
|
func (tun *NativeTun) Close() error {
|
|
tun.close = true
|
|
err1 := tun.closeTUN()
|
|
|
|
if tun.events != nil {
|
|
close(tun.events)
|
|
}
|
|
|
|
_, _, err2 := tun.wt.DeleteInterface(0)
|
|
if err1 == nil {
|
|
err1 = err2
|
|
}
|
|
|
|
windows.CloseHandle(tun.rdEvent)
|
|
windows.CloseHandle(tun.wrEvent)
|
|
|
|
return err1
|
|
}
|
|
|
|
func (tun *NativeTun) MTU() (int, error) {
|
|
return tun.forcedMtu, nil
|
|
}
|
|
|
|
//TODO: This is a temporary hack. We really need to be monitoring the interface in real time and adapting to MTU changes.
|
|
func (tun *NativeTun) ForceMtu(mtu int) {
|
|
tun.forcedMtu = mtu
|
|
}
|
|
|
|
func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
|
|
select {
|
|
case err := <-tun.errors:
|
|
return 0, err
|
|
default:
|
|
}
|
|
|
|
for {
|
|
if tun.rdBuff.offset+packetExchangeAlignment <= tun.rdBuff.avail {
|
|
// Get packet from the exchange buffer.
|
|
packet := tun.rdBuff.data[tun.rdBuff.offset:]
|
|
size := *(*uint32)(unsafe.Pointer(&packet[0]))
|
|
pSize := packetAlign(packetExchangeAlignment + size)
|
|
if packetSizeMax < size || tun.rdBuff.avail < tun.rdBuff.offset+pSize {
|
|
// Invalid packet size.
|
|
tun.rdBuff.avail = 0
|
|
continue
|
|
}
|
|
packet = packet[packetExchangeAlignment : packetExchangeAlignment+size]
|
|
|
|
// Copy data.
|
|
copy(buff[offset:], packet)
|
|
tun.rdBuff.offset += pSize
|
|
return int(size), nil
|
|
}
|
|
|
|
// Get TUN data pipe.
|
|
file, err := tun.getTUN()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
// Fill queue.
|
|
var n uint32
|
|
overlapped := &windows.Overlapped{HEvent: tun.rdEvent}
|
|
err = windows.ReadFile(file, tun.rdBuff.data[:], &n, overlapped)
|
|
if err != nil {
|
|
if en, ok := err.(syscall.Errno); ok && en == windows.ERROR_IO_PENDING {
|
|
err = getOverlappedResult(file, overlapped, &n, true)
|
|
}
|
|
if err != nil {
|
|
tun.rdBuff.avail = 0
|
|
if tun.isIOCancelled(err) {
|
|
return 0, err
|
|
}
|
|
tun.closeTUN()
|
|
continue
|
|
}
|
|
}
|
|
tun.rdBuff.offset = 0
|
|
tun.rdBuff.avail = uint32(n)
|
|
}
|
|
}
|
|
|
|
// Note: flush() and putTunPacket() assume the caller comes only from a single thread; there's no locking.
|
|
|
|
func (tun *NativeTun) flush() error {
|
|
// Get TUN data pipe.
|
|
file, err := tun.getTUN()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Flush write buffer.
|
|
var n uint32
|
|
overlapped := &windows.Overlapped{HEvent: tun.wrEvent}
|
|
err = windows.WriteFile(file, tun.wrBuff.data[:tun.wrBuff.offset], &n, overlapped)
|
|
tun.wrBuff.packetNum = 0
|
|
tun.wrBuff.offset = 0
|
|
if err != nil {
|
|
if en, ok := err.(syscall.Errno); ok && en == windows.ERROR_IO_PENDING {
|
|
err = getOverlappedResult(file, overlapped, &n, true)
|
|
}
|
|
if err != nil {
|
|
if tun.isIOCancelled(err) {
|
|
return err
|
|
}
|
|
tun.closeTUN()
|
|
return nil
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (tun *NativeTun) putTunPacket(buff []byte) error {
|
|
size := uint32(len(buff))
|
|
if size == 0 {
|
|
return errors.New("Empty packet")
|
|
}
|
|
if size > packetSizeMax {
|
|
return errors.New("Packet too big")
|
|
}
|
|
pSize := packetAlign(packetExchangeAlignment + size)
|
|
|
|
if tun.wrBuff.packetNum >= packetExchangeMax || tun.wrBuff.offset+pSize >= packetExchangeSize {
|
|
// Exchange buffer is full -> flush first.
|
|
err := tun.flush()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
// Write packet to the exchange buffer.
|
|
packet := tun.wrBuff.data[tun.wrBuff.offset : tun.wrBuff.offset+pSize]
|
|
*(*uint32)(unsafe.Pointer(&packet[0])) = size
|
|
packet = packet[packetExchangeAlignment : packetExchangeAlignment+size]
|
|
copy(packet, buff)
|
|
|
|
tun.wrBuff.packetNum++
|
|
tun.wrBuff.offset += pSize
|
|
|
|
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()
|
|
}
|
|
|
|
//
|
|
// GUID returns Windows adapter instance ID.
|
|
//
|
|
func (tun *NativeTun) GUID() windows.GUID {
|
|
return *(*windows.GUID)(tun.wt)
|
|
}
|