wintun: move ring constants into module

This commit is contained in:
Jason A. Donenfeld 2019-08-29 12:47:16 -06:00
parent fa7763c268
commit 353f0956bc
3 changed files with 133 additions and 96 deletions

View File

@ -19,40 +19,11 @@ import (
)
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)
rateMeasurementGranularity = uint64((time.Second / 2) / time.Nanosecond)
spinloopRateThreshold = 800000000 / 8 // 800mbps
spinloopDuration = uint64(time.Millisecond / 80 / time.Nanosecond) // ~1gbit/s
)
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
}
}
type rateJuggler struct {
current uint64
nextByteCount uint64
@ -64,7 +35,7 @@ type NativeTun struct {
wt *wintun.Interface
handle windows.Handle
close bool
rings ringDescriptor
rings wintun.RingDescriptor
events chan Event
errors chan error
forcedMTU int
@ -79,10 +50,6 @@ func procyield(cycles uint32)
//go:linkname nanotime runtime.nanotime
func nanotime() int64
func packetAlign(size uint32) uint32 {
return (size + (packetAlignment - 1)) &^ (packetAlignment - 1)
}
//
// CreateTUN creates a Wintun interface with the given name. Should a Wintun
// interface with the same name exist, it is reused.
@ -127,30 +94,13 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Dev
forcedMTU: 1500,
}
tun.rings.send.size = uint32(unsafe.Sizeof(ring{}))
tun.rings.send.ring = &ring{}
tun.rings.send.tailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
err = tun.rings.Init()
if err != nil {
tun.Close()
return nil, fmt.Errorf("Error creating event: %v", err)
return nil, fmt.Errorf("Error creating events: %v", err)
}
tun.rings.receive.size = uint32(unsafe.Sizeof(ring{}))
tun.rings.receive.ring = &ring{}
tun.rings.receive.tailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
if err != nil {
tun.Close()
return nil, fmt.Errorf("Error creating event: %v", err)
}
tun.handle, err = tun.wt.Handle()
if err != nil {
tun.Close()
return nil, err
}
var bytesReturned uint32
err = windows.DeviceIoControl(tun.handle, ioctlRegisterRings, (*byte)(unsafe.Pointer(&tun.rings)), uint32(unsafe.Sizeof(tun.rings)), nil, 0, &bytesReturned, nil)
tun.handle, err = tun.wt.Register(&tun.rings)
if err != nil {
tun.Close()
return nil, fmt.Errorf("Error registering rings: %v", err)
@ -172,18 +122,13 @@ func (tun *NativeTun) Events() chan Event {
func (tun *NativeTun) Close() error {
tun.close = true
if tun.rings.send.tailMoved != 0 {
windows.SetEvent(tun.rings.send.tailMoved) // wake the reader if it's sleeping
if tun.rings.Send.TailMoved != 0 {
windows.SetEvent(tun.rings.Send.TailMoved) // wake the reader if it's sleeping
}
if tun.handle != windows.InvalidHandle {
windows.CloseHandle(tun.handle)
}
if tun.rings.send.tailMoved != 0 {
windows.CloseHandle(tun.rings.send.tailMoved)
}
if tun.rings.send.tailMoved != 0 {
windows.CloseHandle(tun.rings.receive.tailMoved)
}
tun.rings.Close()
var err error
if tun.wt != nil {
_, err = tun.wt.DeleteInterface()
@ -214,8 +159,8 @@ retry:
return 0, os.ErrClosed
}
buffHead := atomic.LoadUint32(&tun.rings.send.ring.head)
if buffHead >= packetCapacity {
buffHead := atomic.LoadUint32(&tun.rings.Send.Ring.Head)
if buffHead >= wintun.PacketCapacity {
return 0, os.ErrClosed
}
@ -223,7 +168,7 @@ retry:
shouldSpin := atomic.LoadUint64(&tun.rate.current) >= spinloopRateThreshold && uint64(start-atomic.LoadInt64(&tun.rate.nextStartTime)) <= rateMeasurementGranularity*2
var buffTail uint32
for {
buffTail = atomic.LoadUint32(&tun.rings.send.ring.tail)
buffTail = atomic.LoadUint32(&tun.rings.Send.Ring.Tail)
if buffHead != buffTail {
break
}
@ -231,35 +176,35 @@ retry:
return 0, os.ErrClosed
}
if !shouldSpin || uint64(nanotime()-start) >= spinloopDuration {
windows.WaitForSingleObject(tun.rings.send.tailMoved, windows.INFINITE)
windows.WaitForSingleObject(tun.rings.Send.TailMoved, windows.INFINITE)
goto retry
}
procyield(1)
}
if buffTail >= packetCapacity {
if buffTail >= wintun.PacketCapacity {
return 0, os.ErrClosed
}
buffContent := tun.rings.send.ring.wrap(buffTail - buffHead)
if buffContent < uint32(unsafe.Sizeof(packetHeader{})) {
buffContent := tun.rings.Send.Ring.Wrap(buffTail - buffHead)
if buffContent < uint32(unsafe.Sizeof(wintun.PacketHeader{})) {
return 0, errors.New("incomplete packet header in send ring")
}
packet := (*packet)(unsafe.Pointer(&tun.rings.send.ring.data[buffHead]))
if packet.size > packetSizeMax {
packet := (*wintun.Packet)(unsafe.Pointer(&tun.rings.Send.Ring.Data[buffHead]))
if packet.Size > wintun.PacketSizeMax {
return 0, errors.New("packet too big in send ring")
}
alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packet.size)
alignedPacketSize := wintun.PacketAlign(uint32(unsafe.Sizeof(wintun.PacketHeader{})) + packet.Size)
if alignedPacketSize > buffContent {
return 0, errors.New("incomplete packet in send ring")
}
copy(buff[offset:], packet.data[:packet.size])
buffHead = tun.rings.send.ring.wrap(buffHead + alignedPacketSize)
atomic.StoreUint32(&tun.rings.send.ring.head, buffHead)
tun.rate.update(uint64(packet.size))
return int(packet.size), nil
copy(buff[offset:], packet.Data[:packet.Size])
buffHead = tun.rings.Send.Ring.Wrap(buffHead + alignedPacketSize)
atomic.StoreUint32(&tun.rings.Send.Ring.Head, buffHead)
tun.rate.update(uint64(packet.Size))
return int(packet.Size), nil
}
func (tun *NativeTun) Flush() error {
@ -273,29 +218,29 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
packetSize := uint32(len(buff) - offset)
tun.rate.update(uint64(packetSize))
alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packetSize)
alignedPacketSize := wintun.PacketAlign(uint32(unsafe.Sizeof(wintun.PacketHeader{})) + packetSize)
buffHead := atomic.LoadUint32(&tun.rings.receive.ring.head)
if buffHead >= packetCapacity {
buffHead := atomic.LoadUint32(&tun.rings.Receive.Ring.Head)
if buffHead >= wintun.PacketCapacity {
return 0, os.ErrClosed
}
buffTail := atomic.LoadUint32(&tun.rings.receive.ring.tail)
if buffTail >= packetCapacity {
buffTail := atomic.LoadUint32(&tun.rings.Receive.Ring.Tail)
if buffTail >= wintun.PacketCapacity {
return 0, os.ErrClosed
}
buffSpace := tun.rings.receive.ring.wrap(buffHead - buffTail - packetAlignment)
buffSpace := tun.rings.Receive.Ring.Wrap(buffHead - buffTail - wintun.PacketAlignment)
if alignedPacketSize > buffSpace {
return 0, nil // Dropping when ring is full.
}
packet := (*packet)(unsafe.Pointer(&tun.rings.receive.ring.data[buffTail]))
packet.size = packetSize
copy(packet.data[:packetSize], buff[offset:])
atomic.StoreUint32(&tun.rings.receive.ring.tail, tun.rings.receive.ring.wrap(buffTail+alignedPacketSize))
if atomic.LoadInt32(&tun.rings.receive.ring.alertable) != 0 {
windows.SetEvent(tun.rings.receive.tailMoved)
packet := (*wintun.Packet)(unsafe.Pointer(&tun.rings.Receive.Ring.Data[buffTail]))
packet.Size = packetSize
copy(packet.Data[:packetSize], buff[offset:])
atomic.StoreUint32(&tun.rings.Receive.Ring.Tail, tun.rings.Receive.Ring.Wrap(buffTail+alignedPacketSize))
if atomic.LoadInt32(&tun.rings.Receive.Ring.Alertable) != 0 {
windows.SetEvent(tun.rings.Receive.TailMoved)
}
return int(packetSize), nil
}
@ -305,11 +250,6 @@ func (tun *NativeTun) LUID() uint64 {
return tun.wt.LUID()
}
// wrap returns value modulo ring capacity
func (rb *ring) wrap(value uint32) uint32 {
return value & (packetCapacity - 1)
}
func (rate *rateJuggler) update(packetLen uint64) {
now := nanotime()
total := atomic.AddUint64(&rate.nextByteCount, packetLen)

97
tun/wintun/ring.go Normal file
View File

@ -0,0 +1,97 @@
/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
*/
package wintun
import (
"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 (descriptor *RingDescriptor) Init() (err error) {
descriptor.Send.Size = uint32(unsafe.Sizeof(Ring{}))
descriptor.Send.Ring = &Ring{}
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{}
descriptor.Receive.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
if err != nil {
windows.CloseHandle(descriptor.Send.TailMoved)
return
}
return
}
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
}

View File

@ -698,8 +698,8 @@ func (wintun *Interface) deviceData() (setupapi.DevInfo, *setupapi.DevInfoData,
return 0, nil, windows.ERROR_OBJECT_NOT_FOUND
}
// Handle returns a handle to the interface device object.
func (wintun *Interface) Handle() (windows.Handle, error) {
// handle returns a handle to the interface device object.
func (wintun *Interface) handle() (windows.Handle, error) {
interfaces, err := setupapi.CM_Get_Device_Interface_List(wintun.devInstanceID, &deviceInterfaceNetGUID, setupapi.CM_GET_DEVICE_INTERFACE_LIST_PRESENT)
if err != nil {
return windows.InvalidHandle, fmt.Errorf("Error listing NDIS interfaces: %v", err)