chore: better REJECT process

tunnel/tunnel.go

@@ -406,29 +406,36 @@ func handleTCPConn(connCtx C.ConnContext) {
 
 	ctx, cancel := context.WithTimeout(context.Background(), C.DefaultTCPTimeout)
 	defer cancel()
-	remoteConn, err := retry(ctx, func(ctx context.Context) (C.Conn, error) {
-		remoteConn, err := proxy.DialContext(ctx, dialMetadata)
+	remoteConn, err := retry(ctx, func(ctx context.Context) (remoteConn C.Conn, err error) {
+		remoteConn, err = proxy.DialContext(ctx, dialMetadata)
 		if err != nil {
-			return nil, err
-		}
-		for _, chain := range remoteConn.Chains() {
-			if chain == "REJECT" {
-				return remoteConn, nil
-			}
+			return
 		}
+
 		if N.NeedHandshake(remoteConn) {
+			defer func() {
+				for _, chain := range remoteConn.Chains() {
+					if chain == "REJECT" {
+						err = nil
+						return
+					}
+				}
+				if err != nil {
+					remoteConn = nil
+				}
+			}()
 			peekMutex.Lock()
 			defer peekMutex.Unlock()
 			peekBytes, _ = conn.Peek(conn.Buffered())
 			_, err = remoteConn.Write(peekBytes)
 			if err != nil {
-				return nil, err
+				return
 			}
 			if peekLen = len(peekBytes); peekLen > 0 {
 				_, _ = conn.Discard(peekLen)
 			}
 		}
-		return remoteConn, err
+		return
 	}, func(err error) {
 		if rule == nil {
 			log.Warnln(