109 lines
3.2 KiB
Go
109 lines
3.2 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
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*/
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package wintun
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import (
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"syscall"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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type Session struct {
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handle uintptr
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}
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const (
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PacketSizeMax = 0xffff // Maximum packet size
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RingCapacityMin = 0x20000 // Minimum ring capacity (128 kiB)
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RingCapacityMax = 0x4000000 // Maximum ring capacity (64 MiB)
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)
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// Packet with data
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type Packet struct {
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Next *Packet // Pointer to next packet in queue
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Size uint32 // Size of packet (max WINTUN_MAX_IP_PACKET_SIZE)
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Data *[PacketSizeMax]byte // Pointer to layer 3 IPv4 or IPv6 packet
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}
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var (
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procWintunAllocateSendPacket = modwintun.NewProc("WintunAllocateSendPacket")
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procWintunEndSession = modwintun.NewProc("WintunEndSession")
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procWintunGetReadWaitEvent = modwintun.NewProc("WintunGetReadWaitEvent")
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procWintunReceivePacket = modwintun.NewProc("WintunReceivePacket")
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procWintunReleaseReceivePacket = modwintun.NewProc("WintunReleaseReceivePacket")
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procWintunSendPacket = modwintun.NewProc("WintunSendPacket")
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procWintunStartSession = modwintun.NewProc("WintunStartSession")
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)
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func (wintun *Adapter) StartSession(capacity uint32) (session Session, err error) {
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r0, _, e1 := syscall.Syscall(procWintunStartSession.Addr(), 2, uintptr(wintun.handle), uintptr(capacity), 0)
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if r0 == 0 {
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err = e1
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} else {
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session = Session{r0}
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}
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return
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}
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func (session Session) End() {
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syscall.Syscall(procWintunEndSession.Addr(), 1, session.handle, 0, 0)
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session.handle = 0
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}
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func (session Session) ReadWaitEvent() (handle windows.Handle) {
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r0, _, _ := syscall.Syscall(procWintunGetReadWaitEvent.Addr(), 1, session.handle, 0, 0)
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handle = windows.Handle(r0)
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return
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}
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func (session Session) ReceivePacket() (packet []byte, err error) {
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var packetSize uint32
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r0, _, e1 := syscall.Syscall(procWintunReceivePacket.Addr(), 2, session.handle, uintptr(unsafe.Pointer(&packetSize)), 0)
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if r0 == 0 {
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err = e1
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return
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}
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unsafeSlice(unsafe.Pointer(&packet), unsafe.Pointer(r0), int(packetSize))
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return
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}
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func (session Session) ReleaseReceivePacket(packet []byte) {
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syscall.Syscall(procWintunReleaseReceivePacket.Addr(), 2, session.handle, uintptr(unsafe.Pointer(&packet[0])), 0)
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}
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func (session Session) AllocateSendPacket(packetSize int) (packet []byte, err error) {
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r0, _, e1 := syscall.Syscall(procWintunAllocateSendPacket.Addr(), 2, session.handle, uintptr(packetSize), 0)
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if r0 == 0 {
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err = e1
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return
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}
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unsafeSlice(unsafe.Pointer(&packet), unsafe.Pointer(r0), int(packetSize))
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return
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}
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func (session Session) SendPacket(packet []byte) {
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syscall.Syscall(procWintunSendPacket.Addr(), 2, session.handle, uintptr(unsafe.Pointer(&packet[0])), 0)
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}
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// unsafeSlice updates the slice slicePtr to be a slice
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// referencing the provided data with its length & capacity set to
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// lenCap.
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//
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// TODO: when Go 1.16 or Go 1.17 is the minimum supported version,
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// update callers to use unsafe.Slice instead of this.
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func unsafeSlice(slicePtr, data unsafe.Pointer, lenCap int) {
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type sliceHeader struct {
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Data unsafe.Pointer
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Len int
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Cap int
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}
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h := (*sliceHeader)(slicePtr)
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h.Data = data
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h.Len = lenCap
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h.Cap = lenCap
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}
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