mirror of
https://github.com/KusakabeShi/EtherGuard-VPN.git
synced 2024-12-11 16:40:40 +01:00
118 lines
3.1 KiB
Go
118 lines
3.1 KiB
Go
/* SPDX-License-Identifier: MIT
|
|
*
|
|
* Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
|
|
*/
|
|
|
|
package wintun
|
|
|
|
import (
|
|
"runtime"
|
|
"unsafe"
|
|
|
|
"golang.org/x/sys/windows"
|
|
)
|
|
|
|
const (
|
|
PacketAlignment = 4 // Number of bytes packets are aligned to in rings
|
|
PacketSizeMax = 0xffff // Maximum packet size
|
|
PacketCapacity = 0x800000 // Ring capacity, 8MiB
|
|
PacketTrailingSize = uint32(unsafe.Sizeof(PacketHeader{})) + ((PacketSizeMax + (PacketAlignment - 1)) &^ (PacketAlignment - 1)) - PacketAlignment
|
|
ioctlRegisterRings = (51820 << 16) | (0x970 << 2) | 0 /*METHOD_BUFFERED*/ | (0x3 /*FILE_READ_DATA | FILE_WRITE_DATA*/ << 14)
|
|
)
|
|
|
|
type PacketHeader struct {
|
|
Size uint32
|
|
}
|
|
|
|
type Packet struct {
|
|
PacketHeader
|
|
Data [PacketSizeMax]byte
|
|
}
|
|
|
|
type Ring struct {
|
|
Head uint32
|
|
Tail uint32
|
|
Alertable int32
|
|
Data [PacketCapacity + PacketTrailingSize]byte
|
|
}
|
|
|
|
type RingDescriptor struct {
|
|
Send, Receive struct {
|
|
Size uint32
|
|
Ring *Ring
|
|
TailMoved windows.Handle
|
|
}
|
|
}
|
|
|
|
// Wrap returns value modulo ring capacity
|
|
func (rb *Ring) Wrap(value uint32) uint32 {
|
|
return value & (PacketCapacity - 1)
|
|
}
|
|
|
|
// Aligns a packet size to PacketAlignment
|
|
func PacketAlign(size uint32) uint32 {
|
|
return (size + (PacketAlignment - 1)) &^ (PacketAlignment - 1)
|
|
}
|
|
|
|
func NewRingDescriptor() (descriptor *RingDescriptor, err error) {
|
|
descriptor = new(RingDescriptor)
|
|
allocatedRegion, err := windows.VirtualAlloc(0, unsafe.Sizeof(Ring{})*2, windows.MEM_COMMIT|windows.MEM_RESERVE, windows.PAGE_READWRITE)
|
|
if err != nil {
|
|
return
|
|
}
|
|
defer func() {
|
|
if err != nil {
|
|
descriptor.free()
|
|
descriptor = nil
|
|
}
|
|
}()
|
|
descriptor.Send.Size = uint32(unsafe.Sizeof(Ring{}))
|
|
descriptor.Send.Ring = (*Ring)(unsafe.Pointer(allocatedRegion))
|
|
descriptor.Send.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
descriptor.Receive.Size = uint32(unsafe.Sizeof(Ring{}))
|
|
descriptor.Receive.Ring = (*Ring)(unsafe.Pointer(allocatedRegion + unsafe.Sizeof(Ring{})))
|
|
descriptor.Receive.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
|
|
if err != nil {
|
|
windows.CloseHandle(descriptor.Send.TailMoved)
|
|
return
|
|
}
|
|
runtime.SetFinalizer(descriptor, func(d *RingDescriptor) { d.free() })
|
|
return
|
|
}
|
|
|
|
func (descriptor *RingDescriptor) free() {
|
|
if descriptor.Send.Ring != nil {
|
|
windows.VirtualFree(uintptr(unsafe.Pointer(descriptor.Send.Ring)), 0, windows.MEM_RELEASE)
|
|
descriptor.Send.Ring = nil
|
|
descriptor.Receive.Ring = nil
|
|
}
|
|
}
|
|
|
|
func (descriptor *RingDescriptor) Close() {
|
|
if descriptor.Send.TailMoved != 0 {
|
|
windows.CloseHandle(descriptor.Send.TailMoved)
|
|
descriptor.Send.TailMoved = 0
|
|
}
|
|
if descriptor.Send.TailMoved != 0 {
|
|
windows.CloseHandle(descriptor.Receive.TailMoved)
|
|
descriptor.Receive.TailMoved = 0
|
|
}
|
|
}
|
|
|
|
func (wintun *Interface) Register(descriptor *RingDescriptor) (windows.Handle, error) {
|
|
handle, err := wintun.handle()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
var bytesReturned uint32
|
|
err = windows.DeviceIoControl(handle, ioctlRegisterRings, (*byte)(unsafe.Pointer(descriptor)), uint32(unsafe.Sizeof(*descriptor)), nil, 0, &bytesReturned, nil)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
return handle, nil
|
|
}
|