diff --git a/tun/tun_windows.go b/tun/tun_windows.go
index 684d6f0..63eb812 100644
--- a/tun/tun_windows.go
+++ b/tun/tun_windows.go
@@ -9,10 +9,9 @@ import (
"errors"
"fmt"
"os"
- "sync"
"sync/atomic"
"time"
- "unsafe"
+ _ "unsafe"
"golang.org/x/sys/windows"
@@ -40,8 +39,8 @@ type NativeTun struct {
errors chan error
forcedMTU int
rate rateJuggler
- rings *wintun.RingDescriptor
- writeLock sync.Mutex
+ session wintun.Session
+ readWait windows.Handle
}
var WintunPool *wintun.Pool
@@ -103,17 +102,13 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu
forcedMTU: forcedMTU,
}
- tun.rings, err = wintun.NewRingDescriptor()
+ tun.session, err = wt.StartSession(0x800000) // Ring capacity, 8 MiB
if err != nil {
- tun.Close()
- return nil, fmt.Errorf("Error creating events: %v", err)
- }
-
- tun.handle, err = tun.wt.Register(tun.rings)
- if err != nil {
- tun.Close()
- return nil, fmt.Errorf("Error registering rings: %v", err)
+ _, err = tun.wt.Delete(false)
+ close(tun.events)
+ return nil, fmt.Errorf("Error starting session: %v", err)
}
+ tun.readWait = tun.session.ReadWaitEvent()
return tun, nil
}
@@ -131,13 +126,7 @@ 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.handle != windows.InvalidHandle {
- windows.CloseHandle(tun.handle)
- }
- tun.rings.Close()
+ tun.session.End()
var err error
if tun.wt != nil {
_, err = tun.wt.Delete(false)
@@ -164,56 +153,34 @@ retry:
return 0, err
default:
}
- if tun.close {
- return 0, os.ErrClosed
- }
-
- buffHead := atomic.LoadUint32(&tun.rings.Send.Ring.Head)
- if buffHead >= wintun.PacketCapacity {
- return 0, os.ErrClosed
- }
-
start := nanotime()
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)
- if buffHead != buffTail {
- break
- }
if tun.close {
return 0, os.ErrClosed
}
- if !shouldSpin || uint64(nanotime()-start) >= spinloopDuration {
- windows.WaitForSingleObject(tun.rings.Send.TailMoved, windows.INFINITE)
- goto retry
+ packet, err := tun.session.ReceivePacket()
+ switch err {
+ case nil:
+ packetSize := len(packet)
+ copy(buff[offset:], packet)
+ tun.session.ReleaseReceivePacket(packet)
+ tun.rate.update(uint64(packetSize))
+ return packetSize, nil
+ case windows.ERROR_NO_MORE_ITEMS:
+ if !shouldSpin || uint64(nanotime()-start) >= spinloopDuration {
+ windows.WaitForSingleObject(tun.readWait, windows.INFINITE)
+ goto retry
+ }
+ procyield(1)
+ continue
+ case windows.ERROR_HANDLE_EOF:
+ return 0, os.ErrClosed
+ case windows.ERROR_INVALID_DATA:
+ return 0, errors.New("Send ring corrupt")
}
- procyield(1)
+ return 0, fmt.Errorf("Read failed: %v", err)
}
- if buffTail >= wintun.PacketCapacity {
- return 0, os.ErrClosed
- }
-
- 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 := (*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 := 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
}
func (tun *NativeTun) Flush() error {
@@ -225,36 +192,22 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
return 0, os.ErrClosed
}
- packetSize := uint32(len(buff) - offset)
+ packetSize := len(buff) - offset
tun.rate.update(uint64(packetSize))
- alignedPacketSize := wintun.PacketAlign(uint32(unsafe.Sizeof(wintun.PacketHeader{})) + packetSize)
- tun.writeLock.Lock()
- defer tun.writeLock.Unlock()
-
- buffHead := atomic.LoadUint32(&tun.rings.Receive.Ring.Head)
- if buffHead >= wintun.PacketCapacity {
- return 0, os.ErrClosed
+ packet, err := tun.session.AllocateSendPacket(packetSize)
+ if err == nil {
+ copy(packet, buff[offset:])
+ tun.session.SendPacket(packet)
+ return packetSize, nil
}
-
- buffTail := atomic.LoadUint32(&tun.rings.Receive.Ring.Tail)
- if buffTail >= wintun.PacketCapacity {
+ switch err {
+ case windows.ERROR_HANDLE_EOF:
return 0, os.ErrClosed
- }
-
- buffSpace := tun.rings.Receive.Ring.Wrap(buffHead - buffTail - wintun.PacketAlignment)
- if alignedPacketSize > buffSpace {
+ case windows.ERROR_BUFFER_OVERFLOW:
return 0, nil // Dropping when ring is full.
}
-
- 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
+ return 0, fmt.Errorf("Write failed: %v", err)
}
// LUID returns Windows interface instance ID.
diff --git a/tun/wintun/ring_windows.go b/tun/wintun/ring_windows.go
deleted file mode 100644
index ed460fb..0000000
--- a/tun/wintun/ring_windows.go
+++ /dev/null
@@ -1,117 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2020 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 *Adapter) Register(descriptor *RingDescriptor) (windows.Handle, error) {
- handle, err := wintun.OpenAdapterDeviceObject()
- 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
-}
diff --git a/tun/wintun/session_windows.go b/tun/wintun/session_windows.go
new file mode 100644
index 0000000..1619e5a
--- /dev/null
+++ b/tun/wintun/session_windows.go
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2020 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+ "syscall"
+ "unsafe"
+
+ "golang.org/x/sys/windows"
+)
+
+type Session struct {
+ handle uintptr
+}
+
+const (
+ PacketSizeMax = 0xffff // Maximum packet size
+ RingCapacityMin = 0x20000 // Minimum ring capacity (128 kiB)
+ RingCapacityMax = 0x4000000 // Maximum ring capacity (64 MiB)
+)
+
+// Packet with data
+type Packet struct {
+ Next *Packet // Pointer to next packet in queue
+ Size uint32 // Size of packet (max WINTUN_MAX_IP_PACKET_SIZE)
+ Data *[PacketSizeMax]byte // Pointer to layer 3 IPv4 or IPv6 packet
+}
+
+var (
+ procWintunAllocateSendPacket = modwintun.NewProc("WintunAllocateSendPacket").Addr()
+ procWintunEndSession = modwintun.NewProc("WintunEndSession")
+ procWintunGetReadWaitEvent = modwintun.NewProc("WintunGetReadWaitEvent")
+ procWintunReceivePacket = modwintun.NewProc("WintunReceivePacket").Addr()
+ procWintunReleaseReceivePacket = modwintun.NewProc("WintunReleaseReceivePacket").Addr()
+ procWintunSendPacket = modwintun.NewProc("WintunSendPacket").Addr()
+ procWintunStartSession = modwintun.NewProc("WintunStartSession")
+)
+
+func (wintun *Adapter) StartSession(capacity uint32) (session Session, err error) {
+ r0, _, e1 := syscall.Syscall(procWintunStartSession.Addr(), 2, uintptr(wintun.handle), uintptr(capacity), 0)
+ if r0 == 0 {
+ err = e1
+ } else {
+ session = Session{r0}
+ }
+ return
+}
+
+func (session Session) End() {
+ syscall.Syscall(procWintunEndSession.Addr(), 1, session.handle, 0, 0)
+ session.handle = 0
+}
+
+func (session Session) ReadWaitEvent() (handle windows.Handle) {
+ r0, _, _ := syscall.Syscall(procWintunGetReadWaitEvent.Addr(), 1, session.handle, 0, 0)
+ handle = windows.Handle(r0)
+ return
+}
+
+func (session Session) ReceivePacket() (packet []byte, err error) {
+ var packetSize uint32
+ r0, _, e1 := syscall.Syscall(procWintunReceivePacket, 2, session.handle, uintptr(unsafe.Pointer(&packetSize)), 0)
+ if r0 == 0 {
+ err = e1
+ return
+ }
+ unsafeSlice(unsafe.Pointer(&packet), unsafe.Pointer(r0), int(packetSize))
+ return
+}
+
+func (session Session) ReleaseReceivePacket(packet []byte) {
+ syscall.Syscall(procWintunReleaseReceivePacket, 2, session.handle, uintptr(unsafe.Pointer(&packet[0])), 0)
+}
+
+func (session Session) AllocateSendPacket(packetSize int) (packet []byte, err error) {
+ r0, _, e1 := syscall.Syscall(procWintunAllocateSendPacket, 2, session.handle, uintptr(packetSize), 0)
+ if r0 == 0 {
+ err = e1
+ return
+ }
+ unsafeSlice(unsafe.Pointer(&packet), unsafe.Pointer(r0), int(packetSize))
+ return
+}
+
+func (session Session) SendPacket(packet []byte) {
+ syscall.Syscall(procWintunSendPacket, 2, session.handle, uintptr(unsafe.Pointer(&packet[0])), 0)
+}
+
+// unsafeSlice updates the slice slicePtr to be a slice
+// referencing the provided data with its length & capacity set to
+// lenCap.
+//
+// TODO: when Go 1.16 or Go 1.17 is the minimum supported version,
+// update callers to use unsafe.Slice instead of this.
+func unsafeSlice(slicePtr, data unsafe.Pointer, lenCap int) {
+ type sliceHeader struct {
+ Data unsafe.Pointer
+ Len int
+ Cap int
+ }
+ h := (*sliceHeader)(slicePtr)
+ h.Data = data
+ h.Len = lenCap
+ h.Cap = lenCap
+}
diff --git a/tun/wintun/wintun_windows.go b/tun/wintun/wintun_windows.go
index ac33579..e7ba8b6 100644
--- a/tun/wintun/wintun_windows.go
+++ b/tun/wintun/wintun_windows.go
@@ -45,7 +45,6 @@ var (
procWintunGetAdapterLUID = modwintun.NewProc("WintunGetAdapterLUID")
procWintunGetAdapterName = modwintun.NewProc("WintunGetAdapterName")
procWintunGetRunningDriverVersion = modwintun.NewProc("WintunGetRunningDriverVersion")
- procWintunOpenAdapterDeviceObject = modwintun.NewProc("WintunOpenAdapterDeviceObject")
procWintunSetAdapterName = modwintun.NewProc("WintunSetAdapterName")
procWintunSetLogger = modwintun.NewProc("WintunSetLogger")
)
@@ -210,16 +209,6 @@ func RunningVersion() (version uint32, err error) {
return
}
-// handle returns a handle to the adapter device object. Release handle with windows.CloseHandle
-func (wintun *Adapter) OpenAdapterDeviceObject() (handle windows.Handle, err error) {
- r0, _, e1 := syscall.Syscall(procWintunOpenAdapterDeviceObject.Addr(), 1, uintptr(wintun.handle), 0, 0)
- handle = windows.Handle(r0)
- if handle == windows.InvalidHandle {
- err = e1
- }
- return
-}
-
// LUID returns the LUID of the adapter.
func (wintun *Adapter) LUID() (luid uint64) {
syscall.Syscall(procWintunGetAdapterLUID.Addr(), 2, uintptr(wintun.handle), uintptr(unsafe.Pointer(&luid)), 0)