wintun: move ring constants into module
This commit is contained in:
Jason A. Donenfeld
parent
fa7763c268
commit
353f0956bc
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@ -19,40 +19,11 @@ import (
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)
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const (
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packetAlignment = 4 // Number of bytes packets are aligned to in rings
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packetSizeMax = 0xffff // Maximum packet size
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packetCapacity = 0x800000 // Ring capacity, 8MiB
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packetTrailingSize = uint32(unsafe.Sizeof(packetHeader{})) + ((packetSizeMax + (packetAlignment - 1)) &^ (packetAlignment - 1)) - packetAlignment
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ioctlRegisterRings = (51820 << 16) | (0x970 << 2) | 0 /*METHOD_BUFFERED*/ | (0x3 /*FILE_READ_DATA | FILE_WRITE_DATA*/ << 14)
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rateMeasurementGranularity = uint64((time.Second / 2) / time.Nanosecond)
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spinloopRateThreshold = 800000000 / 8 // 800mbps
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spinloopDuration = uint64(time.Millisecond / 80 / time.Nanosecond) // ~1gbit/s
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)
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type packetHeader struct {
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size uint32
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}
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type packet struct {
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packetHeader
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data [packetSizeMax]byte
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}
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type ring struct {
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head uint32
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tail uint32
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alertable int32
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data [packetCapacity + packetTrailingSize]byte
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}
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type ringDescriptor struct {
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send, receive struct {
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size uint32
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ring *ring
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tailMoved windows.Handle
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}
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}
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type rateJuggler struct {
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current uint64
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nextByteCount uint64
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@ -64,7 +35,7 @@ type NativeTun struct {
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wt *wintun.Interface
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handle windows.Handle
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close bool
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rings ringDescriptor
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rings wintun.RingDescriptor
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events chan Event
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errors chan error
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forcedMTU int
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@ -79,10 +50,6 @@ func procyield(cycles uint32)
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//go:linkname nanotime runtime.nanotime
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func nanotime() int64
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func packetAlign(size uint32) uint32 {
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return (size + (packetAlignment - 1)) &^ (packetAlignment - 1)
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}
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//
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// CreateTUN creates a Wintun interface with the given name. Should a Wintun
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// interface with the same name exist, it is reused.
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@ -127,30 +94,13 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Dev
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forcedMTU: 1500,
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}
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tun.rings.send.size = uint32(unsafe.Sizeof(ring{}))
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tun.rings.send.ring = &ring{}
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tun.rings.send.tailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
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err = tun.rings.Init()
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if err != nil {
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tun.Close()
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return nil, fmt.Errorf("Error creating event: %v", err)
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return nil, fmt.Errorf("Error creating events: %v", err)
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}
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tun.rings.receive.size = uint32(unsafe.Sizeof(ring{}))
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tun.rings.receive.ring = &ring{}
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tun.rings.receive.tailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
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if err != nil {
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tun.Close()
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return nil, fmt.Errorf("Error creating event: %v", err)
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}
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tun.handle, err = tun.wt.Handle()
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if err != nil {
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tun.Close()
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return nil, err
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}
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var bytesReturned uint32
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err = windows.DeviceIoControl(tun.handle, ioctlRegisterRings, (*byte)(unsafe.Pointer(&tun.rings)), uint32(unsafe.Sizeof(tun.rings)), nil, 0, &bytesReturned, nil)
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tun.handle, err = tun.wt.Register(&tun.rings)
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if err != nil {
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tun.Close()
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return nil, fmt.Errorf("Error registering rings: %v", err)
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@ -172,18 +122,13 @@ func (tun *NativeTun) Events() chan Event {
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func (tun *NativeTun) Close() error {
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tun.close = true
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if tun.rings.send.tailMoved != 0 {
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windows.SetEvent(tun.rings.send.tailMoved) // wake the reader if it's sleeping
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if tun.rings.Send.TailMoved != 0 {
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windows.SetEvent(tun.rings.Send.TailMoved) // wake the reader if it's sleeping
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}
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if tun.handle != windows.InvalidHandle {
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windows.CloseHandle(tun.handle)
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}
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if tun.rings.send.tailMoved != 0 {
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windows.CloseHandle(tun.rings.send.tailMoved)
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}
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if tun.rings.send.tailMoved != 0 {
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windows.CloseHandle(tun.rings.receive.tailMoved)
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}
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tun.rings.Close()
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var err error
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if tun.wt != nil {
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_, err = tun.wt.DeleteInterface()
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@ -214,8 +159,8 @@ retry:
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return 0, os.ErrClosed
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}
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buffHead := atomic.LoadUint32(&tun.rings.send.ring.head)
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if buffHead >= packetCapacity {
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buffHead := atomic.LoadUint32(&tun.rings.Send.Ring.Head)
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if buffHead >= wintun.PacketCapacity {
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return 0, os.ErrClosed
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}
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@ -223,7 +168,7 @@ retry:
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shouldSpin := atomic.LoadUint64(&tun.rate.current) >= spinloopRateThreshold && uint64(start-atomic.LoadInt64(&tun.rate.nextStartTime)) <= rateMeasurementGranularity*2
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var buffTail uint32
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for {
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buffTail = atomic.LoadUint32(&tun.rings.send.ring.tail)
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buffTail = atomic.LoadUint32(&tun.rings.Send.Ring.Tail)
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if buffHead != buffTail {
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break
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}
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@ -231,35 +176,35 @@ retry:
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return 0, os.ErrClosed
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}
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if !shouldSpin || uint64(nanotime()-start) >= spinloopDuration {
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windows.WaitForSingleObject(tun.rings.send.tailMoved, windows.INFINITE)
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windows.WaitForSingleObject(tun.rings.Send.TailMoved, windows.INFINITE)
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goto retry
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}
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procyield(1)
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}
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if buffTail >= packetCapacity {
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if buffTail >= wintun.PacketCapacity {
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return 0, os.ErrClosed
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}
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buffContent := tun.rings.send.ring.wrap(buffTail - buffHead)
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if buffContent < uint32(unsafe.Sizeof(packetHeader{})) {
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buffContent := tun.rings.Send.Ring.Wrap(buffTail - buffHead)
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if buffContent < uint32(unsafe.Sizeof(wintun.PacketHeader{})) {
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return 0, errors.New("incomplete packet header in send ring")
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}
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packet := (*packet)(unsafe.Pointer(&tun.rings.send.ring.data[buffHead]))
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if packet.size > packetSizeMax {
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packet := (*wintun.Packet)(unsafe.Pointer(&tun.rings.Send.Ring.Data[buffHead]))
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if packet.Size > wintun.PacketSizeMax {
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return 0, errors.New("packet too big in send ring")
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}
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alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packet.size)
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alignedPacketSize := wintun.PacketAlign(uint32(unsafe.Sizeof(wintun.PacketHeader{})) + packet.Size)
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if alignedPacketSize > buffContent {
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return 0, errors.New("incomplete packet in send ring")
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}
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copy(buff[offset:], packet.data[:packet.size])
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buffHead = tun.rings.send.ring.wrap(buffHead + alignedPacketSize)
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atomic.StoreUint32(&tun.rings.send.ring.head, buffHead)
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tun.rate.update(uint64(packet.size))
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return int(packet.size), nil
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copy(buff[offset:], packet.Data[:packet.Size])
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buffHead = tun.rings.Send.Ring.Wrap(buffHead + alignedPacketSize)
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atomic.StoreUint32(&tun.rings.Send.Ring.Head, buffHead)
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tun.rate.update(uint64(packet.Size))
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return int(packet.Size), nil
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}
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func (tun *NativeTun) Flush() error {
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@ -273,29 +218,29 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
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packetSize := uint32(len(buff) - offset)
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tun.rate.update(uint64(packetSize))
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alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packetSize)
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alignedPacketSize := wintun.PacketAlign(uint32(unsafe.Sizeof(wintun.PacketHeader{})) + packetSize)
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buffHead := atomic.LoadUint32(&tun.rings.receive.ring.head)
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if buffHead >= packetCapacity {
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buffHead := atomic.LoadUint32(&tun.rings.Receive.Ring.Head)
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if buffHead >= wintun.PacketCapacity {
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return 0, os.ErrClosed
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}
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buffTail := atomic.LoadUint32(&tun.rings.receive.ring.tail)
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if buffTail >= packetCapacity {
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buffTail := atomic.LoadUint32(&tun.rings.Receive.Ring.Tail)
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if buffTail >= wintun.PacketCapacity {
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return 0, os.ErrClosed
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}
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buffSpace := tun.rings.receive.ring.wrap(buffHead - buffTail - packetAlignment)
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buffSpace := tun.rings.Receive.Ring.Wrap(buffHead - buffTail - wintun.PacketAlignment)
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if alignedPacketSize > buffSpace {
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return 0, nil // Dropping when ring is full.
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}
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packet := (*packet)(unsafe.Pointer(&tun.rings.receive.ring.data[buffTail]))
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packet.size = packetSize
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copy(packet.data[:packetSize], buff[offset:])
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atomic.StoreUint32(&tun.rings.receive.ring.tail, tun.rings.receive.ring.wrap(buffTail+alignedPacketSize))
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if atomic.LoadInt32(&tun.rings.receive.ring.alertable) != 0 {
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windows.SetEvent(tun.rings.receive.tailMoved)
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packet := (*wintun.Packet)(unsafe.Pointer(&tun.rings.Receive.Ring.Data[buffTail]))
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packet.Size = packetSize
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copy(packet.Data[:packetSize], buff[offset:])
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atomic.StoreUint32(&tun.rings.Receive.Ring.Tail, tun.rings.Receive.Ring.Wrap(buffTail+alignedPacketSize))
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if atomic.LoadInt32(&tun.rings.Receive.Ring.Alertable) != 0 {
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windows.SetEvent(tun.rings.Receive.TailMoved)
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}
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return int(packetSize), nil
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}
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@ -305,11 +250,6 @@ func (tun *NativeTun) LUID() uint64 {
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return tun.wt.LUID()
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}
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// wrap returns value modulo ring capacity
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func (rb *ring) wrap(value uint32) uint32 {
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return value & (packetCapacity - 1)
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}
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func (rate *rateJuggler) update(packetLen uint64) {
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now := nanotime()
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total := atomic.AddUint64(&rate.nextByteCount, packetLen)
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97
tun/wintun/ring.go
Normal file
97
tun/wintun/ring.go
Normal file
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@ -0,0 +1,97 @@
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/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
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*/
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package wintun
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import (
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"unsafe"
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"golang.org/x/sys/windows"
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)
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const (
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PacketAlignment = 4 // Number of bytes packets are aligned to in rings
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PacketSizeMax = 0xffff // Maximum packet size
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PacketCapacity = 0x800000 // Ring capacity, 8MiB
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PacketTrailingSize = uint32(unsafe.Sizeof(PacketHeader{})) + ((PacketSizeMax + (PacketAlignment - 1)) &^ (PacketAlignment - 1)) - PacketAlignment
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ioctlRegisterRings = (51820 << 16) | (0x970 << 2) | 0 /*METHOD_BUFFERED*/ | (0x3 /*FILE_READ_DATA | FILE_WRITE_DATA*/ << 14)
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)
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type PacketHeader struct {
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Size uint32
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}
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type Packet struct {
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PacketHeader
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Data [PacketSizeMax]byte
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}
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type Ring struct {
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Head uint32
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Tail uint32
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Alertable int32
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Data [PacketCapacity + PacketTrailingSize]byte
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}
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type RingDescriptor struct {
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Send, Receive struct {
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Size uint32
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Ring *Ring
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TailMoved windows.Handle
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}
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}
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// Wrap returns value modulo ring capacity
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func (rb *Ring) Wrap(value uint32) uint32 {
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return value & (PacketCapacity - 1)
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}
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// Aligns a packet size to PacketAlignment
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func PacketAlign(size uint32) uint32 {
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return (size + (PacketAlignment - 1)) &^ (PacketAlignment - 1)
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}
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func (descriptor *RingDescriptor) Init() (err error) {
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descriptor.Send.Size = uint32(unsafe.Sizeof(Ring{}))
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descriptor.Send.Ring = &Ring{}
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descriptor.Send.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
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if err != nil {
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return
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}
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descriptor.Receive.Size = uint32(unsafe.Sizeof(Ring{}))
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descriptor.Receive.Ring = &Ring{}
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descriptor.Receive.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
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if err != nil {
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windows.CloseHandle(descriptor.Send.TailMoved)
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return
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}
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return
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}
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func (descriptor *RingDescriptor) Close() {
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if descriptor.Send.TailMoved != 0 {
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windows.CloseHandle(descriptor.Send.TailMoved)
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descriptor.Send.TailMoved = 0
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}
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if descriptor.Send.TailMoved != 0 {
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windows.CloseHandle(descriptor.Receive.TailMoved)
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descriptor.Receive.TailMoved = 0
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}
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}
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func (wintun *Interface) Register(descriptor *RingDescriptor) (windows.Handle, error) {
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handle, err := wintun.handle()
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if err != nil {
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return 0, err
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}
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var bytesReturned uint32
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err = windows.DeviceIoControl(handle, ioctlRegisterRings, (*byte)(unsafe.Pointer(descriptor)), uint32(unsafe.Sizeof(*descriptor)), nil, 0, &bytesReturned, nil)
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if err != nil {
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return 0, err
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}
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return handle, nil
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}
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@ -698,8 +698,8 @@ func (wintun *Interface) deviceData() (setupapi.DevInfo, *setupapi.DevInfoData,
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return 0, nil, windows.ERROR_OBJECT_NOT_FOUND
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}
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// Handle returns a handle to the interface device object.
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func (wintun *Interface) Handle() (windows.Handle, error) {
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// handle returns a handle to the interface device object.
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func (wintun *Interface) handle() (windows.Handle, error) {
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interfaces, err := setupapi.CM_Get_Device_Interface_List(wintun.devInstanceID, &deviceInterfaceNetGUID, setupapi.CM_GET_DEVICE_INTERFACE_LIST_PRESENT)
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if err != nil {
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return windows.InvalidHandle, fmt.Errorf("Error listing NDIS interfaces: %v", err)
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