diff --git a/common/cond.go b/common/cond.go
index 6cf44cf..b8aa731 100644
--- a/common/cond.go
+++ b/common/cond.go
@@ -147,9 +147,9 @@ func Close(closers ...any) error {
 		}
 		switch c := closer.(type) {
 		case ReaderWithUpstream:
-			err = Close(c.Upstream())
+			err = Close(c.UpstreamReader())
 		case WriterWithUpstream:
-			err = Close(c.Upstream())
+			err = Close(c.UpstreamWriter())
 		}
 		if err != nil {
 			retErr = err
diff --git a/common/flush.go b/common/flush.go
index bdbc381..db004ba 100644
--- a/common/flush.go
+++ b/common/flush.go
@@ -18,16 +18,16 @@ func Flush(writer io.Writer) error {
 			}
 		}
 		if u, ok := writer.(WriterWithUpstream); ok {
-			if u.Replaceable() {
+			if u.WriterReplaceable() {
 				if writerBack == writer {
-				} else if setter, hasSetter := u.Upstream().(UpstreamWriterSetter); hasSetter {
+				} else if setter, hasSetter := u.UpstreamWriter().(UpstreamWriterSetter); hasSetter {
 					setter.SetWriter(writerBack)
-					writer = u.Upstream()
+					writer = u.UpstreamWriter()
 					continue
 				}
 			}
 			writerBack = writer
-			writer = u.Upstream()
+			writer = u.UpstreamWriter()
 		} else {
 			break
 		}
@@ -46,20 +46,20 @@ func FlushVar(writerP *io.Writer) error {
 			}
 		}
 		if u, ok := writer.(WriterWithUpstream); ok {
-			if u.Replaceable() {
+			if u.WriterReplaceable() {
 				if writerBack == writer {
-					writer = u.Upstream()
+					writer = u.UpstreamWriter()
 					writerBack = writer
 					*writerP = writer
 					continue
 				} else if setter, hasSetter := writerBack.(UpstreamWriterSetter); hasSetter {
-					setter.SetWriter(u.Upstream())
-					writer = u.Upstream()
+					setter.SetWriter(u.UpstreamWriter())
+					writer = u.UpstreamWriter()
 					continue
 				}
 			}
 			writerBack = writer
-			writer = u.Upstream()
+			writer = u.UpstreamWriter()
 		} else {
 			break
 		}
@@ -72,11 +72,11 @@ type FlushOnceWriter struct {
 	flushed bool
 }
 
-func (w *FlushOnceWriter) Upstream() io.Writer {
+func (w *FlushOnceWriter) UpstreamWriter() io.Writer {
 	return w.Writer
 }
 
-func (w *FlushOnceWriter) Replaceable() bool {
+func (w *FlushOnceWriter) WriterReplaceable() bool {
 	return w.flushed
 }
 
diff --git a/common/rw/buffer.go b/common/rw/buffer.go
index 0b60ff0..ac22ebe 100644
--- a/common/rw/buffer.go
+++ b/common/rw/buffer.go
@@ -12,11 +12,11 @@ type BufferedWriter struct {
 	Buffer *buf.Buffer
 }
 
-func (w *BufferedWriter) Upstream() io.Writer {
+func (w *BufferedWriter) UpstreamWriter() io.Writer {
 	return w.Writer
 }
 
-func (w *BufferedWriter) Replaceable() bool {
+func (w *BufferedWriter) WriterReplaceable() bool {
 	return w.Buffer == nil
 }
 
@@ -85,11 +85,11 @@ type HeaderWriter struct {
 	Header *buf.Buffer
 }
 
-func (w *HeaderWriter) Upstream() io.Writer {
+func (w *HeaderWriter) UpstreamWriter() io.Writer {
 	return w.Writer
 }
 
-func (w *HeaderWriter) Replaceable() bool {
+func (w *HeaderWriter) WriterReplaceable() bool {
 	return w.Header == nil
 }
 
diff --git a/common/rw/copy.go b/common/rw/copy.go
index bc0827c..0472c82 100644
--- a/common/rw/copy.go
+++ b/common/rw/copy.go
@@ -25,13 +25,13 @@ func ReadFromVar(writerVar *io.Writer, reader io.Reader) (int64, error) {
 			}
 		}
 		if u, ok := writer.(common.WriterWithUpstream); ok {
-			if u.Replaceable() && writerBack == writer {
-				writer = u.Upstream()
+			if u.WriterReplaceable() && writerBack == writer {
+				writer = u.UpstreamWriter()
 				writerBack = writer
 				writerVar = &writer
 				continue
 			}
-			writer = u.Upstream()
+			writer = u.UpstreamWriter()
 			writerBack = writer
 		} else {
 			break
diff --git a/common/rw/duplex.go b/common/rw/duplex.go
index 5c809b5..eaaf77d 100644
--- a/common/rw/duplex.go
+++ b/common/rw/duplex.go
@@ -1,6 +1,8 @@
 package rw
 
-import "io"
+import (
+	"github.com/sagernet/sing/common"
+)
 
 type ReadCloser interface {
 	CloseRead() error
@@ -10,16 +12,32 @@ type WriteCloser interface {
 	CloseWrite() error
 }
 
-func CloseRead(conn io.Closer) error {
-	if closer, ok := conn.(ReadCloser); ok {
-		return closer.CloseRead()
+func CloseRead(reader any) error {
+	r := reader
+	for {
+		if closer, ok := r.(ReadCloser); ok {
+			return closer.CloseRead()
+		}
+		if u, ok := r.(common.ReaderWithUpstream); ok {
+			r = u.UpstreamReader()
+			continue
+		}
+		break
 	}
-	return nil
+	return common.Close(reader)
 }
 
-func CloseWrite(conn io.Closer) error {
-	if closer, ok := conn.(WriteCloser); ok {
-		return closer.CloseWrite()
+func CloseWrite(writer any) error {
+	w := writer
+	for {
+		if closer, ok := w.(WriteCloser); ok {
+			return closer.CloseWrite()
+		}
+		if u, ok := w.(common.WriterWithUpstream); ok {
+			w = u.UpstreamWriter()
+			continue
+		}
+		break
 	}
-	return nil
+	return common.Close(writer)
 }
diff --git a/common/upstream.go b/common/upstream.go
index 7bad06f..e9e2f2e 100644
--- a/common/upstream.go
+++ b/common/upstream.go
@@ -5,17 +5,17 @@ import (
 )
 
 type ReaderWithUpstream interface {
-	Upstream() io.Reader
-	Replaceable() bool
+	UpstreamReader() io.Reader
+	ReaderReplaceable() bool
 }
 
 type UpstreamReaderSetter interface {
-	SetUpstream(reader io.Reader)
+	SetReader(reader io.Reader)
 }
 
 type WriterWithUpstream interface {
-	Upstream() io.Writer
-	Replaceable() bool
+	UpstreamWriter() io.Writer
+	WriterReplaceable() bool
 }
 
 type UpstreamWriterSetter interface {
diff --git a/protocol/shadowsocks/shadowaead/aead.go b/protocol/shadowsocks/shadowaead/aead.go
index de3f08a..40127df 100644
--- a/protocol/shadowsocks/shadowaead/aead.go
+++ b/protocol/shadowsocks/shadowaead/aead.go
@@ -41,15 +41,15 @@ func NewRawReader(upstream io.Reader, cipher cipher.AEAD, buffer []byte, nonce [
 	}
 }
 
-func (r *Reader) Upstream() io.Reader {
+func (r *Reader) UpstreamReader() io.Reader {
 	return r.upstream
 }
 
-func (r *Reader) Replaceable() bool {
+func (r *Reader) ReaderReplaceable() bool {
 	return false
 }
 
-func (r *Reader) SetUpstream(reader io.Reader) {
+func (r *Reader) SetReader(reader io.Reader) {
 	r.upstream = reader
 }
 
@@ -226,11 +226,11 @@ func NewRawWriter(upstream io.Writer, cipher cipher.AEAD, maxPacketSize int, buf
 	}
 }
 
-func (w *Writer) Upstream() io.Writer {
+func (w *Writer) UpstreamWriter() io.Writer {
 	return w.upstream
 }
 
-func (w *Writer) Replaceable() bool {
+func (w *Writer) WriterReplaceable() bool {
 	return false
 }
 
@@ -299,11 +299,11 @@ type BufferedWriter struct {
 	index    int
 }
 
-func (w *BufferedWriter) Upstream() io.Writer {
+func (w *BufferedWriter) UpstreamWriter() io.Writer {
 	return w.upstream
 }
 
-func (w *BufferedWriter) Replaceable() bool {
+func (w *BufferedWriter) WriterReplaceable() bool {
 	return w.index == 0
 }
 
diff --git a/protocol/shadowsocks/shadowaead/protocol.go b/protocol/shadowsocks/shadowaead/protocol.go
index 5867417..340409b 100644
--- a/protocol/shadowsocks/shadowaead/protocol.go
+++ b/protocol/shadowsocks/shadowaead/protocol.go
@@ -298,6 +298,28 @@ func (c *clientConn) ReadFrom(r io.Reader) (n int64, err error) {
 	return c.writer.ReadFrom(r)
 }
 
+func (c *clientConn) UpstreamReader() io.Reader {
+	if c.reader == nil {
+		return c.Conn
+	}
+	return c.reader
+}
+
+func (c *clientConn) ReaderReplaceable() bool {
+	return c.reader != nil
+}
+
+func (c *clientConn) UpstreamWriter() io.Writer {
+	if c.writer == nil {
+		return c.Conn
+	}
+	return c.writer
+}
+
+func (c *clientConn) WriterReplaceable() bool {
+	return c.writer != nil
+}
+
 type clientPacketConn struct {
 	*Method
 	net.Conn
@@ -329,3 +351,19 @@ func (c *clientPacketConn) ReadPacket(buffer *buf.Buffer) (*M.AddrPort, error) {
 	}
 	return socks.AddressSerializer.ReadAddrPort(buffer)
 }
+
+func (c *clientPacketConn) UpstreamReader() io.Reader {
+	return c.Conn
+}
+
+func (c *clientPacketConn) ReaderReplaceable() bool {
+	return false
+}
+
+func (c *clientPacketConn) UpstreamWriter() io.Writer {
+	return c.Conn
+}
+
+func (c *clientPacketConn) WriterReplaceable() bool {
+	return false
+}
diff --git a/protocol/shadowsocks/shadowaead/service.go b/protocol/shadowsocks/shadowaead/service.go
index a6c6eb2..9ac1b7e 100644
--- a/protocol/shadowsocks/shadowaead/service.go
+++ b/protocol/shadowsocks/shadowaead/service.go
@@ -168,22 +168,34 @@ func (c *serverConn) WriteTo(w io.Writer) (n int64, err error) {
 	return c.reader.WriteTo(w)
 }
 
+func (c *serverConn) UpstreamReader() io.Reader {
+	if c.reader == nil {
+		return c.Conn
+	}
+	return c.reader
+}
+
+func (c *serverConn) ReaderReplaceable() bool {
+	return c.reader != nil
+}
+
+func (c *serverConn) UpstreamWriter() io.Writer {
+	if c.writer == nil {
+		return c.Conn
+	}
+	return c.writer
+}
+
+func (c *serverConn) WriterReplaceable() bool {
+	return c.writer != nil
+}
+
 func (s *Service) NewPacket(conn socks.PacketConn, buffer *buf.Buffer, metadata M.Metadata) error {
 	if buffer.Len() < s.keySaltLength {
 		return E.New("bad packet")
 	}
 	key := Kdf(s.key, buffer.To(s.keySaltLength), s.keySaltLength)
 	c := s.constructor(common.Dup(key))
-	/*data := buf.New()
-	packet, err := c.Open(data.Index(0), rw.ZeroBytes[:c.NonceSize()], buffer.From(s.keySaltLength), nil)
-	if err != nil {
-		return err
-	}
-	data.Truncate(len(packet))
-	metadata.Protocol = "shadowsocks"
-	return s.udp.NewPacket(metadata.Source.String(), func() socks.PacketWriter {
-		return &serverPacketWriter{s, conn, metadata.Source}
-	}, data, metadata)*/
 	packet, err := c.Open(buffer.Index(s.keySaltLength), rw.ZeroBytes[:c.NonceSize()], buffer.From(s.keySaltLength), nil)
 	if err != nil {
 		return err
diff --git a/protocol/shadowsocks/shadowaead_2022/protocol.go b/protocol/shadowsocks/shadowaead_2022/protocol.go
index 56b0928..a514e42 100644
--- a/protocol/shadowsocks/shadowaead_2022/protocol.go
+++ b/protocol/shadowsocks/shadowaead_2022/protocol.go
@@ -377,6 +377,28 @@ func (c *clientConn) ReadFrom(r io.Reader) (n int64, err error) {
 	return c.writer.ReadFrom(r)
 }
 
+func (c *clientConn) UpstreamReader() io.Reader {
+	if c.reader == nil {
+		return c.Conn
+	}
+	return c.reader
+}
+
+func (c *clientConn) ReaderReplaceable() bool {
+	return c.reader != nil
+}
+
+func (c *clientConn) UpstreamWriter() io.Writer {
+	if c.writer == nil {
+		return c.Conn
+	}
+	return c.writer
+}
+
+func (c *clientConn) WriterReplaceable() bool {
+	return c.writer != nil
+}
+
 type clientPacketConn struct {
 	net.Conn
 	method  *Method
@@ -582,3 +604,19 @@ func (m *Method) newUDPSession() *udpSession {
 	}
 	return session
 }
+
+func (c *clientPacketConn) UpstreamReader() io.Reader {
+	return c.Conn
+}
+
+func (c *clientPacketConn) ReaderReplaceable() bool {
+	return false
+}
+
+func (c *clientPacketConn) UpstreamWriter() io.Writer {
+	return c.Conn
+}
+
+func (c *clientPacketConn) WriterReplaceable() bool {
+	return false
+}
diff --git a/protocol/shadowsocks/shadowaead_2022/service.go b/protocol/shadowsocks/shadowaead_2022/service.go
index 30e48a9..2e7dac3 100644
--- a/protocol/shadowsocks/shadowaead_2022/service.go
+++ b/protocol/shadowsocks/shadowaead_2022/service.go
@@ -207,6 +207,28 @@ func (c *serverConn) WriteTo(w io.Writer) (n int64, err error) {
 	return c.reader.WriteTo(w)
 }
 
+func (c *serverConn) UpstreamReader() io.Reader {
+	if c.reader == nil {
+		return c.Conn
+	}
+	return c.reader
+}
+
+func (c *serverConn) ReaderReplaceable() bool {
+	return c.reader != nil
+}
+
+func (c *serverConn) UpstreamWriter() io.Writer {
+	if c.writer == nil {
+		return c.Conn
+	}
+	return c.writer
+}
+
+func (c *serverConn) WriterReplaceable() bool {
+	return c.writer != nil
+}
+
 func (s *Service) NewPacket(conn socks.PacketConn, buffer *buf.Buffer, metadata M.Metadata) error {
 	var packetHeader []byte
 	if s.udpCipher != nil {