Fix default network strategy

common/dialer/tfo.go

@@ -10,6 +10,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/bufio"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
@@ -24,9 +25,7 @@ type slowOpenConn struct {
 	destination M.Socksaddr
 	conn        net.Conn
 	create      chan struct{}
-	done        chan struct{}
 	access      sync.Mutex
-	closeOnce   sync.Once
 	err         error
 }
 
@@ -45,7 +44,6 @@ func DialSlowContext(dialer *tcpDialer, ctx context.Context, network string, des
 		network:     network,
 		destination: destination,
 		create:      make(chan struct{}),
-		done:        make(chan struct{}),
 	}, nil
 }
 
@@ -56,8 +54,8 @@ func (c *slowOpenConn) Read(b []byte) (n int, err error) {
 			if c.err != nil {
 				return 0, c.err
 			}
-		case <-c.done:
-			return 0, os.ErrClosed
+		case <-c.ctx.Done():
+			return 0, c.ctx.Err()
 		}
 	}
 	return c.conn.Read(b)
@@ -75,8 +73,6 @@ func (c *slowOpenConn) Write(b []byte) (n int, err error) {
 			return 0, c.err
 		}
 		return c.conn.Write(b)
-	case <-c.done:
-		return 0, os.ErrClosed
 	default:
 	}
 	conn, err := c.dialer.DialContext(c.ctx, c.network, c.destination.String(), b)
@@ -91,13 +87,7 @@ func (c *slowOpenConn) Write(b []byte) (n int, err error) {
 }
 
 func (c *slowOpenConn) Close() error {
-	c.closeOnce.Do(func() {
-		close(c.done)
-		if c.conn != nil {
-			c.conn.Close()
-		}
-	})
-	return nil
+	return common.Close(c.conn)
 }
 
 func (c *slowOpenConn) LocalAddr() net.Addr {
@@ -162,8 +152,8 @@ func (c *slowOpenConn) WriteTo(w io.Writer) (n int64, err error) {
 			if c.err != nil {
 				return 0, c.err
 			}
-		case <-c.done:
-			return 0, c.err
+		case <-c.ctx.Done():
+			return 0, c.ctx.Err()
 		}
 	}
 	return bufio.Copy(w, c.conn)