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Diffstat (limited to 'tun/tun_windows.go')
-rw-r--r--tun/tun_windows.go304
1 files changed, 91 insertions, 213 deletions
diff --git a/tun/tun_windows.go b/tun/tun_windows.go
index 5da5a70..6a84394 100644
--- a/tun/tun_windows.go
+++ b/tun/tun_windows.go
@@ -9,7 +9,6 @@ import (
"errors"
"fmt"
"os"
- "sync"
"sync/atomic"
"time"
"unsafe"
@@ -21,14 +20,10 @@ import (
const (
packetAlignment uint32 = 4 // Number of bytes packets are aligned to in rings
- packetSizeMax uint32 = 0xffff // Maximum packet size
- packetCapacity uint32 = 0x800000 // Ring capacity, 8MiB
- packetTrailingSize uint32 = uint32(unsafe.Sizeof(packetHeader{})) + ((packetSizeMax + (packetAlignment - 1)) &^ (packetAlignment - 1)) - packetAlignment
-
- ioctlRegisterRings uint32 = (51820 << 16) | (0x970 << 2) | 0 /*METHOD_BUFFERED*/ | (0x3 /*FILE_READ_DATA | FILE_WRITE_DATA*/ << 14)
-
- retryRate = 4 // Number of retries per second to reopen device pipe
- retryTimeout = 30 // Number of seconds to tolerate adapter unavailable
+ 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 {
@@ -57,8 +52,7 @@ type ringDescriptor struct {
type NativeTun struct {
wt *wintun.Wintun
- tunDev windows.Handle
- tunLock sync.Mutex
+ handle windows.Handle
close bool
rings ringDescriptor
events chan Event
@@ -70,15 +64,6 @@ func packetAlign(size uint32) uint32 {
return (size + (packetAlignment - 1)) &^ (packetAlignment - 1)
}
-var shouldRetryOpen = windows.RtlGetVersion().MajorVersion < 10
-
-func maybeRetry(x int) int {
- if shouldRetryOpen {
- return x
- }
- return 0
-}
-
//
// CreateTUN creates a Wintun adapter with the given name. Should a Wintun
// adapter with the same name exist, it is reused.
@@ -119,7 +104,7 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Dev
tun := &NativeTun{
wt: wt,
- tunDev: windows.InvalidHandle,
+ handle: windows.InvalidHandle,
events: make(chan Event, 10),
errors: make(chan error, 1),
forcedMTU: 1500,
@@ -129,7 +114,7 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Dev
tun.rings.send.ring = &ring{}
tun.rings.send.tailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
if err != nil {
- wt.DeleteInterface()
+ tun.Close()
return nil, fmt.Errorf("Error creating event: %v", err)
}
@@ -137,98 +122,23 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Dev
tun.rings.receive.ring = &ring{}
tun.rings.receive.tailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
if err != nil {
- windows.CloseHandle(tun.rings.send.tailMoved)
- wt.DeleteInterface()
+ tun.Close()
return nil, fmt.Errorf("Error creating event: %v", err)
}
- _, err = tun.getTUN()
+ tun.handle, err = tun.wt.AdapterHandle()
if err != nil {
- windows.CloseHandle(tun.rings.send.tailMoved)
- windows.CloseHandle(tun.rings.receive.tailMoved)
- tun.closeTUN()
- wt.DeleteInterface()
+ tun.Close()
return nil, err
}
- return tun, nil
-}
-
-func (tun *NativeTun) openTUN() error {
- filename, err := tun.wt.NdisFileName()
- if err != nil {
- return err
- }
-
- retries := maybeRetry(retryTimeout * retryRate)
- if tun.close {
- return os.ErrClosed
- }
-
- name, err := windows.UTF16PtrFromString(filename)
+ var bytesReturned uint32
+ err = windows.DeviceIoControl(tun.handle, ioctlRegisterRings, (*byte)(unsafe.Pointer(&tun.rings)), uint32(unsafe.Sizeof(tun.rings)), nil, 0, &bytesReturned, nil)
if err != nil {
- return err
+ tun.Close()
+ return nil, fmt.Errorf("Error registering rings: %v", err)
}
- for tun.tunDev == windows.InvalidHandle {
- tun.tunDev, err = windows.CreateFile(name, windows.GENERIC_READ|windows.GENERIC_WRITE, 0, nil, windows.OPEN_EXISTING, 0, 0)
- if err != nil {
- if retries > 0 && !tun.close {
- time.Sleep(time.Second / retryRate)
- retries--
- continue
- }
- return err
- }
-
- atomic.StoreUint32(&tun.rings.send.ring.head, 0)
- atomic.StoreUint32(&tun.rings.send.ring.tail, 0)
- atomic.StoreInt32(&tun.rings.send.ring.alertable, 0)
- atomic.StoreUint32(&tun.rings.receive.ring.head, 0)
- atomic.StoreUint32(&tun.rings.receive.ring.tail, 0)
- atomic.StoreInt32(&tun.rings.receive.ring.alertable, 0)
-
- var bytesReturned uint32
- err = windows.DeviceIoControl(tun.tunDev, ioctlRegisterRings, (*byte)(unsafe.Pointer(&tun.rings)), uint32(unsafe.Sizeof(tun.rings)), nil, 0, &bytesReturned, nil)
- if err != nil {
- return fmt.Errorf("Error registering rings: %v", err)
- }
- }
- return nil
-}
-
-func (tun *NativeTun) closeTUN() (err error) {
- for tun.tunDev != windows.InvalidHandle {
- tun.tunLock.Lock()
- if tun.tunDev == windows.InvalidHandle {
- tun.tunLock.Unlock()
- break
- }
- t := tun.tunDev
- tun.tunDev = windows.InvalidHandle
- err = windows.CloseHandle(t)
- tun.tunLock.Unlock()
- break
- }
- return
-}
-
-func (tun *NativeTun) getTUN() (handle windows.Handle, err error) {
- handle = tun.tunDev
- if handle == windows.InvalidHandle {
- tun.tunLock.Lock()
- if tun.tunDev != windows.InvalidHandle {
- handle = tun.tunDev
- tun.tunLock.Unlock()
- return
- }
- err = tun.openTUN()
- if err == nil {
- handle = tun.tunDev
- }
- tun.tunLock.Unlock()
- return
- }
- return
+ return tun, nil
}
func (tun *NativeTun) Name() (string, error) {
@@ -245,29 +155,22 @@ func (tun *NativeTun) Events() chan Event {
func (tun *NativeTun) Close() error {
tun.close = true
- windows.SetEvent(tun.rings.send.tailMoved) // wake the reader if it's sleeping
- var err, err2 error
- err = tun.closeTUN()
-
- if tun.events != nil {
- close(tun.events)
+ if tun.rings.send.tailMoved != 0 {
+ windows.SetEvent(tun.rings.send.tailMoved) // wake the reader if it's sleeping
}
-
- err2 = windows.CloseHandle(tun.rings.receive.tailMoved)
- if err == nil {
- err = err2
+ if tun.handle != windows.InvalidHandle {
+ windows.CloseHandle(tun.handle)
}
-
- err2 = windows.CloseHandle(tun.rings.send.tailMoved)
- if err == nil {
- err = err2
+ if tun.rings.send.tailMoved != 0 {
+ windows.CloseHandle(tun.rings.send.tailMoved)
}
-
- _, err2 = tun.wt.DeleteInterface()
- if err == nil {
- err = err2
+ if tun.rings.send.tailMoved != 0 {
+ windows.CloseHandle(tun.rings.receive.tailMoved)
+ }
+ var err error
+ if tun.wt != nil {
+ _, err = tun.wt.DeleteInterface()
}
-
return err
}
@@ -286,74 +189,60 @@ func procyield(cycles uint32)
// Note: Read() and Write() assume the caller comes only from a single thread; there's no locking.
func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
+retry:
select {
case err := <-tun.errors:
return 0, err
default:
}
+ if tun.close {
+ return 0, os.ErrClosed
+ }
- retries := maybeRetry(1000)
-top:
- for !tun.close {
- _, err := tun.getTUN()
- if err != nil {
- return 0, err
- }
-
- buffHead := atomic.LoadUint32(&tun.rings.send.ring.head)
- if buffHead >= packetCapacity {
- return 0, errors.New("send ring head out of bounds")
- }
+ buffHead := atomic.LoadUint32(&tun.rings.send.ring.head)
+ if buffHead >= packetCapacity {
+ return 0, os.ErrClosed
+ }
- start := time.Now()
- var buffTail uint32
- for {
- buffTail = atomic.LoadUint32(&tun.rings.send.ring.tail)
- if buffHead != buffTail {
- break
- }
- if tun.close {
- return 0, os.ErrClosed
- }
- if time.Since(start) >= time.Millisecond*50 {
- windows.WaitForSingleObject(tun.rings.send.tailMoved, windows.INFINITE)
- continue top
- }
- procyield(1)
+ start := time.Now()
+ var buffTail uint32
+ for {
+ buffTail = atomic.LoadUint32(&tun.rings.send.ring.tail)
+ if buffHead != buffTail {
+ break
}
- if buffTail >= packetCapacity {
- if retries > 0 {
- tun.closeTUN()
- time.Sleep(time.Millisecond * 2)
- retries--
- continue
- }
- return 0, errors.New("send ring tail out of bounds")
+ if tun.close {
+ return 0, os.ErrClosed
}
- retries = maybeRetry(1000)
-
- buffContent := tun.rings.send.ring.wrap(buffTail - buffHead)
- if buffContent < uint32(unsafe.Sizeof(packetHeader{})) {
- return 0, errors.New("incomplete packet header in send ring")
+ if time.Since(start) >= time.Millisecond*50 {
+ windows.WaitForSingleObject(tun.rings.send.tailMoved, windows.INFINITE)
+ goto retry
}
+ procyield(1)
+ }
+ if buffTail >= packetCapacity {
+ return 0, os.ErrClosed
+ }
- packet := (*packet)(unsafe.Pointer(&tun.rings.send.ring.data[buffHead]))
- if packet.size > packetSizeMax {
- return 0, errors.New("packet too big in send ring")
- }
+ buffContent := tun.rings.send.ring.wrap(buffTail - buffHead)
+ if buffContent < uint32(unsafe.Sizeof(packetHeader{})) {
+ return 0, errors.New("incomplete packet header in send ring")
+ }
- alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packet.size)
- if alignedPacketSize > buffContent {
- return 0, errors.New("incomplete packet in send ring")
- }
+ packet := (*packet)(unsafe.Pointer(&tun.rings.send.ring.data[buffHead]))
+ if packet.size > packetSizeMax {
+ return 0, errors.New("packet too big 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)
- return int(packet.size), nil
+ alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packet.size)
+ if alignedPacketSize > buffContent {
+ return 0, errors.New("incomplete packet in send ring")
}
- return 0, os.ErrClosed
+ copy(buff[offset:], packet.data[:packet.size])
+ buffHead = tun.rings.send.ring.wrap(buffHead + alignedPacketSize)
+ atomic.StoreUint32(&tun.rings.send.ring.head, buffHead)
+ return int(packet.size), nil
}
func (tun *NativeTun) Flush() error {
@@ -361,47 +250,36 @@ func (tun *NativeTun) Flush() error {
}
func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
- retries := maybeRetry(1000)
- for {
- _, err := tun.getTUN()
- if err != nil {
- return 0, err
- }
+ if tun.close {
+ return 0, os.ErrClosed
+ }
- packetSize := uint32(len(buff) - offset)
- alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packetSize)
-
- buffHead := atomic.LoadUint32(&tun.rings.receive.ring.head)
- if buffHead >= packetCapacity {
- if retries > 0 {
- tun.closeTUN()
- time.Sleep(time.Millisecond * 2)
- retries--
- continue
- }
- return 0, errors.New("receive ring head out of bounds")
- }
- retries = maybeRetry(1000)
+ packetSize := uint32(len(buff) - offset)
+ alignedPacketSize := packetAlign(uint32(unsafe.Sizeof(packetHeader{})) + packetSize)
- buffTail := atomic.LoadUint32(&tun.rings.receive.ring.tail)
- if buffTail >= packetCapacity {
- return 0, errors.New("receive ring tail out of bounds")
- }
+ buffHead := atomic.LoadUint32(&tun.rings.receive.ring.head)
+ if buffHead >= packetCapacity {
+ return 0, os.ErrClosed
+ }
- buffSpace := tun.rings.receive.ring.wrap(buffHead - buffTail - packetAlignment)
- if alignedPacketSize > buffSpace {
- return 0, nil // Dropping when ring is full.
- }
+ buffTail := atomic.LoadUint32(&tun.rings.receive.ring.tail)
+ if buffTail >= packetCapacity {
+ return 0, os.ErrClosed
+ }
- 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)
- }
- return int(packetSize), nil
+ buffSpace := tun.rings.receive.ring.wrap(buffHead - buffTail - 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)
}
+ return int(packetSize), nil
}
// LUID returns Windows adapter instance ID.
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.