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tun: windows: get rid of retry logic

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Things work fine on Windows 8.
This commit is contained in:
Jason A. Donenfeld 2019-07-19 13:51:56 +02:00
parent 1b550f6583
commit 3341e2d444
2 changed files with 113 additions and 231 deletions
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192
tun/tun_windows.go
View file

@ -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)
if err != nil {
return 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)
err = windows.DeviceIoControl(tun.handle, 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)
tun.Close()
return nil, 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
if tun.rings.send.tailMoved != 0 {
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)
}
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
}
@ -286,23 +189,19 @@ 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:
}
retries := maybeRetry(1000)
top:
for !tun.close {
_, err := tun.getTUN()
if err != nil {
return 0, err
if tun.close {
return 0, os.ErrClosed
}
buffHead := atomic.LoadUint32(&tun.rings.send.ring.head)
if buffHead >= packetCapacity {
return 0, errors.New("send ring head out of bounds")
return 0, os.ErrClosed
}
start := time.Now()
@ -317,20 +216,13 @@ top:
}
if time.Since(start) >= time.Millisecond*50 {
windows.WaitForSingleObject(tun.rings.send.tailMoved, windows.INFINITE)
continue top
goto retry
}
procyield(1)
}
if buffTail >= packetCapacity {
if retries > 0 {
tun.closeTUN()
time.Sleep(time.Millisecond * 2)
retries--
continue
return 0, os.ErrClosed
}
return 0, errors.New("send ring tail out of bounds")
}
retries = maybeRetry(1000)
buffContent := tun.rings.send.ring.wrap(buffTail - buffHead)
if buffContent < uint32(unsafe.Sizeof(packetHeader{})) {
@ -353,19 +245,13 @@ top:
return int(packet.size), nil
}
return 0, os.ErrClosed
}
func (tun *NativeTun) Flush() error {
return nil
}
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)
@ -373,19 +259,12 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
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, os.ErrClosed
}
return 0, errors.New("receive ring head out of bounds")
}
retries = maybeRetry(1000)
buffTail := atomic.LoadUint32(&tun.rings.receive.ring.tail)
if buffTail >= packetCapacity {
return 0, errors.New("receive ring tail out of bounds")
return 0, os.ErrClosed
}
buffSpace := tun.rings.receive.ring.wrap(buffHead - buffTail - packetAlignment)
@ -402,7 +281,6 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
}
return int(packetSize), nil
}
}
// LUID returns Windows adapter instance ID.
func (tun *NativeTun) LUID() uint64 {

14
tun/wintun/wintun_windows.go
View file

@ -612,21 +612,25 @@ func (wintun *Wintun) deviceData() (setupapi.DevInfo, *setupapi.DevInfoData, err
return 0, nil, windows.ERROR_OBJECT_NOT_FOUND
}
// NdisFileName returns the Wintun NDIS device object name.
func (wintun *Wintun) NdisFileName() (string, error) {
// AdapterHandle returns a handle to the adapter device object.
func (wintun *Wintun) AdapterHandle() (windows.Handle, error) {
key, err := registry.OpenKey(registry.LOCAL_MACHINE, wintun.netRegKeyName(), registry.QUERY_VALUE)
if err != nil {
return "", fmt.Errorf("Network-specific registry key open failed: %v", err)
return windows.InvalidHandle, fmt.Errorf("Network-specific registry key open failed: %v", err)
}
defer key.Close()
// Get the interface name.
pnpInstanceID, err := registryEx.GetStringValue(key, "PnPInstanceId")
if err != nil {
return "", fmt.Errorf("PnpInstanceId registry key read failed: %v", err)
return windows.InvalidHandle, fmt.Errorf("PnPInstanceId registry key read failed: %v", err)
}
mangledPnpNode := strings.ReplaceAll(fmt.Sprintf("%s\\{cac88484-7515-4c03-82e6-71a87abac361}", pnpInstanceID), "\\", "#")
return fmt.Sprintf("\\\\.\\Global\\%s", mangledPnpNode), nil
handle, err := windows.CreateFile(windows.StringToUTF16Ptr(fmt.Sprintf("\\\\.\\Global\\%s", mangledPnpNode)), windows.GENERIC_READ|windows.GENERIC_WRITE, 0, nil, windows.OPEN_EXISTING, 0, 0)
if err != nil {
return windows.InvalidHandle, fmt.Errorf("CreateFile on mangled PnPInstanceId path failed: %v", err)
}
return handle, nil
}
// GUID returns the GUID of the interface.