prevent close of closed

common/signal/timer.go

@@ -15,10 +15,9 @@ type ActivityUpdater interface {
 
 type ActivityTimer struct {
 	sync.RWMutex
-	updated    chan struct{}
-	checkTask  *task.Periodic
-	onTimeout  func()
-	overridden bool
+	updated   chan struct{}
+	checkTask *task.Periodic
+	onTimeout func()
 }
 
 func (t *ActivityTimer) Update() {
@@ -32,16 +31,14 @@ func (t *ActivityTimer) check() error {
 	select {
 	case <-t.updated:
 	default:
-		t.finish(false)
+		t.finish()
 	}
 	return nil
 }
 
-func (t *ActivityTimer) finish(locked bool) {
-	if !locked {
-		t.Lock()
-		defer t.Unlock()
-	}
+func (t *ActivityTimer) finish() {
+	t.Lock()
+	defer t.Unlock()
 
 	if t.onTimeout != nil {
 		t.onTimeout()
@@ -53,12 +50,9 @@ func (t *ActivityTimer) finish(locked bool) {
 	}
 }
 
-func (t *ActivityTimer) setTimeout(timeout time.Duration) {
-	if t.onTimeout == nil {
-		return
-	}
+func (t *ActivityTimer) SetTimeout(timeout time.Duration) {
 	if timeout == 0 {
-		t.finish(true)
+		t.finish()
 		return
 	}
 
@@ -67,26 +61,14 @@ func (t *ActivityTimer) setTimeout(timeout time.Duration) {
 		Execute:  t.check,
 	}
 
+	t.Lock()
+
 	if t.checkTask != nil {
 		t.checkTask.Close()
-		t.overridden = true
 	}
 	t.checkTask = checkTask
 	t.Update()
 	common.Must(checkTask.Start())
-}
-
-func (t *ActivityTimer) SetTimeout(timeout time.Duration) {
-	t.Lock()
-	t.setTimeout(timeout)
-	t.Unlock()
-}
-
-func (t *ActivityTimer) SetTimeoutIfNotOverridden(timeout time.Duration) {
-	t.Lock()
-	if !t.overridden {
-		t.setTimeout(timeout)
-	}
 	t.Unlock()
 }
 

proxy/dns/dns.go

@@ -5,6 +5,7 @@ import (
 	go_errors "errors"
 	"io"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/xtls/xray-core/common"
@@ -369,6 +370,10 @@ type outboundConn struct {
 	access sync.Mutex
 	dialer func() (stat.Connection, error)
 
+	closeOnce sync.Once
+	dialOnce  sync.Once
+	closed    atomic.Bool
+
 	conn      net.Conn
 	connReady chan struct{}
 }
@@ -378,24 +383,28 @@ func (c *outboundConn) dial() error {
 	if err != nil {
 		return err
 	}
+	if c.closed.Load() {
+		return errors.New("connection closed during dial")
+	}
 	c.conn = conn
 	c.connReady <- struct{}{}
 	return nil
 }
 
 func (c *outboundConn) Write(b []byte) (int, error) {
+	c.dialOnce.Do(func() {
+		c.dial()
+	})
 	c.access.Lock()
-
-	if c.conn == nil {
-		if err := c.dial(); err != nil {
-			c.access.Unlock()
-			errors.LogWarningInner(context.Background(), err, "failed to dial outbound connection")
-			return len(b), nil
-		}
-	}
-
+	conn := c.conn
 	c.access.Unlock()
-
+	if conn == nil {
+		_, open := <-c.connReady
+		if !open {
+			return 0, io.EOF
+		}
+		conn = c.conn
+	}
 	return c.conn.Write(b)
 }
 
@@ -417,11 +426,14 @@ func (c *outboundConn) Read(b []byte) (int, error) {
 }
 
 func (c *outboundConn) Close() error {
-	c.access.Lock()
-	close(c.connReady)
-	if c.conn != nil {
-		c.conn.Close()
-	}
-	c.access.Unlock()
+	c.closeOnce.Do(func() {
+		c.access.Lock()
+		c.closed.Store(true)
+		close(c.connReady)
+		if c.conn != nil {
+			c.conn.Close()
+		}
+		c.access.Unlock()
+	})
 	return nil
 }

proxy/proxy.go

@@ -595,10 +595,10 @@ func CopyRawConnIfExist(ctx context.Context, readerConn net.Conn, writerConn net
 			errors.LogInfo(ctx, "CopyRawConn splice")
 			statWriter, _ := writer.(*dispatcher.SizeStatWriter)
 			//runtime.Gosched() // necessary
-			time.Sleep(time.Millisecond)                    // without this, there will be a rare ssl error for freedom splice
-			timer.SetTimeoutIfNotOverridden(24 * time.Hour) // prevent leak, just in case
+			time.Sleep(time.Millisecond)    // without this, there will be a rare ssl error for freedom splice
+			timer.SetTimeout(8 * time.Hour) // prevent leak, just in case
 			if inTimer != nil {
-				inTimer.SetTimeoutIfNotOverridden(24 * time.Hour)
+				inTimer.SetTimeout(8 * time.Hour)
 			}
 			w, err := tc.ReadFrom(readerConn)
 			if readCounter != nil {