Fix unaligned panic on windows

tun_windows.go

@@ -9,14 +9,14 @@ import (
 	"net/netip"
 	"os"
 	"sync"
-	"sync/atomic"
 	"time"
 	"unsafe"
 
 	"github.com/sagernet/sing-tun/internal/winipcfg"
 	"github.com/sagernet/sing-tun/internal/winsys"
 	"github.com/sagernet/sing-tun/internal/wintun"
 	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/atomic"
 	"github.com/sagernet/sing/common/buf"
 	E "github.com/sagernet/sing/common/exceptions"
 	"github.com/sagernet/sing/common/windnsapi"
@@ -34,7 +34,7 @@ type NativeTun struct {
 	rate        rateJuggler
 	running     sync.WaitGroup
 	closeOnce   sync.Once
-	close       int32
+	close       atomic.Int32
 	fwpmSession uintptr
 }
 
@@ -334,13 +334,13 @@ func (t *NativeTun) ReadPacket() ([]byte, func(), error) {
 	t.running.Add(1)
 	defer t.running.Done()
 retry:
-	if atomic.LoadInt32(&t.close) == 1 {
+	if t.close.Load() == 1 {
 		return nil, nil, os.ErrClosed
 	}
 	start := nanotime()
-	shouldSpin := atomic.LoadUint64(&t.rate.current) >= spinloopRateThreshold && uint64(start-atomic.LoadInt64(&t.rate.nextStartTime)) <= rateMeasurementGranularity*2
+	shouldSpin := t.rate.current.Load() >= spinloopRateThreshold && uint64(start-t.rate.nextStartTime.Load()) <= rateMeasurementGranularity*2
 	for {
-		if atomic.LoadInt32(&t.close) == 1 {
+		if t.close.Load() == 1 {
 			return nil, nil, os.ErrClosed
 		}
 		packet, err := t.session.ReceivePacket()
@@ -369,13 +369,13 @@ func (t *NativeTun) ReadFunc(block func(b []byte)) error {
 	t.running.Add(1)
 	defer t.running.Done()
 retry:
-	if atomic.LoadInt32(&t.close) == 1 {
+	if t.close.Load() == 1 {
 		return os.ErrClosed
 	}
 	start := nanotime()
-	shouldSpin := atomic.LoadUint64(&t.rate.current) >= spinloopRateThreshold && uint64(start-atomic.LoadInt64(&t.rate.nextStartTime)) <= rateMeasurementGranularity*2
+	shouldSpin := t.rate.current.Load() >= spinloopRateThreshold && uint64(start-t.rate.nextStartTime.Load()) <= rateMeasurementGranularity*2
 	for {
-		if atomic.LoadInt32(&t.close) == 1 {
+		if t.close.Load() == 1 {
 			return os.ErrClosed
 		}
 		packet, err := t.session.ReceivePacket()
@@ -405,7 +405,7 @@ retry:
 func (t *NativeTun) Write(p []byte) (n int, err error) {
 	t.running.Add(1)
 	defer t.running.Done()
-	if atomic.LoadInt32(&t.close) == 1 {
+	if t.close.Load() == 1 {
 		return 0, os.ErrClosed
 	}
 	t.rate.update(uint64(len(p)))
@@ -427,7 +427,7 @@ func (t *NativeTun) Write(p []byte) (n int, err error) {
 func (t *NativeTun) write(packetElementList [][]byte) (n int, err error) {
 	t.running.Add(1)
 	defer t.running.Done()
-	if atomic.LoadInt32(&t.close) == 1 {
+	if t.close.Load() == 1 {
 		return 0, os.ErrClosed
 	}
 	var packetSize int
@@ -461,7 +461,7 @@ func (t *NativeTun) WriteVectorised(buffers []*buf.Buffer) error {
 func (t *NativeTun) Close() error {
 	var err error
 	t.closeOnce.Do(func() {
-		atomic.StoreInt32(&t.close, 1)
+		t.close.Store(1)
 		windows.SetEvent(t.readWait)
 		t.running.Wait()
 		t.session.End()
@@ -491,24 +491,24 @@ func procyield(cycles uint32)
 func nanotime() int64
 
 type rateJuggler struct {
-	current       uint64
-	nextByteCount uint64
-	nextStartTime int64
-	changing      int32
+	current       atomic.Uint64
+	nextByteCount atomic.Uint64
+	nextStartTime atomic.Int64
+	changing      atomic.Int32
 }
 
 func (rate *rateJuggler) update(packetLen uint64) {
 	now := nanotime()
-	total := atomic.AddUint64(&rate.nextByteCount, packetLen)
-	period := uint64(now - atomic.LoadInt64(&rate.nextStartTime))
+	total := rate.nextByteCount.Add(packetLen)
+	period := uint64(now - rate.nextStartTime.Load())
 	if period >= rateMeasurementGranularity {
-		if !atomic.CompareAndSwapInt32(&rate.changing, 0, 1) {
+		if !rate.changing.CompareAndSwap(0, 1) {
 			return
 		}
-		atomic.StoreInt64(&rate.nextStartTime, now)
-		atomic.StoreUint64(&rate.current, total*uint64(time.Second/time.Nanosecond)/period)
-		atomic.StoreUint64(&rate.nextByteCount, 0)
-		atomic.StoreInt32(&rate.changing, 0)
+		rate.nextStartTime.Store(now)
+		rate.current.Store(total * uint64(time.Second/time.Nanosecond) / period)
+		rate.nextByteCount.Store(0)
+		rate.changing.Store(0)
 	}
 }