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Diffstat (limited to 'tun/tun_windows.go')
-rw-r--r--tun/tun_windows.go128
1 files changed, 34 insertions, 94 deletions
diff --git a/tun/tun_windows.go b/tun/tun_windows.go
index 1891d21..9c635b5 100644
--- a/tun/tun_windows.go
+++ b/tun/tun_windows.go
@@ -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)
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.