diff --git a/proxy/http/server.go b/proxy/http/server.go
index dccd7c7..1316da9 100644
--- a/proxy/http/server.go
+++ b/proxy/http/server.go
@@ -46,12 +46,14 @@ func (s *HTTP) Serve(cc net.Conn) {
 	defer cc.Close()
 
 	var c *conn.Conn
-	switch ccc := cc.(type) {
-	case *net.TCPConn:
-		ccc.SetKeepAlive(true)
-		c = conn.NewConn(ccc)
+	switch cc := cc.(type) {
 	case *conn.Conn:
-		c = ccc
+		c = cc
+	case *net.TCPConn:
+		cc.SetKeepAlive(true)
+		c = conn.NewConn(cc)
+	default:
+		c = conn.NewConn(cc)
 	}
 
 	req, err := parseRequest(c.Reader())
diff --git a/proxy/mixed/mixed.go b/proxy/mixed/mixed.go
index e59e554..54f7a04 100644
--- a/proxy/mixed/mixed.go
+++ b/proxy/mixed/mixed.go
@@ -88,7 +88,6 @@ func (m *Mixed) Serve(c net.Conn) {
 	}
 
 	cc := conn.NewConn(c)
-
 	head, err := cc.Peek(1)
 	if err != nil {
 		// log.F("[mixed] socks5 peek error: %s", err)
diff --git a/proxy/socks5/socks5.go b/proxy/socks5/socks5.go
index c6f0165..5e754e0 100644
--- a/proxy/socks5/socks5.go
+++ b/proxy/socks5/socks5.go
@@ -103,16 +103,11 @@ func (s *Socks5) ListenAndServeTCP() {
 }
 
 // Serve serves a connection.
-func (s *Socks5) Serve(cc net.Conn) {
-	defer cc.Close()
+func (s *Socks5) Serve(c net.Conn) {
+	defer c.Close()
 
-	var c *conn.Conn
-	switch ccc := cc.(type) {
-	case *net.TCPConn:
-		ccc.SetKeepAlive(true)
-		c = conn.NewConn(ccc)
-	case *conn.Conn:
-		c = ccc
+	if c, ok := c.(*net.TCPConn); ok {
+		c.SetKeepAlive(true)
 	}
 
 	tgt, err := s.handshake(c)