fix: avoid tls panic

transport/vmess/websocket.go

@@ -324,19 +324,34 @@ func streamWebsocketConn(ctx context.Context, conn net.Conn, c *WebsocketConfig,
 		return nil, fmt.Errorf("parse url %s error: %w", c.Path, err)
 	}
 
-	scheme := "ws"
+	uri := url.URL{
+		Scheme:   "ws",
+		Host:     net.JoinHostPort(c.Host, c.Port),
+		Path:     u.Path,
+		RawQuery: u.RawQuery,
+	}
+
 	if c.TLS {
-		scheme = "wss"
+		uri.Scheme = "wss"
+		config := c.TLSConfig
+		if config == nil { // The config cannot be nil
+			config = &tls.Config{NextProtos: []string{"http/1.1"}}
+		}
+		if config.ServerName == "" && !config.InsecureSkipVerify { // users must set either ServerName or InsecureSkipVerify in the config.
+			config = config.Clone()
+			config.ServerName = uri.Host
+		}
+
 		if len(c.ClientFingerprint) != 0 {
 			if fingerprint, exists := tlsC.GetFingerprint(c.ClientFingerprint); exists {
-				utlsConn := tlsC.UClient(conn, c.TLSConfig, fingerprint)
+				utlsConn := tlsC.UClient(conn, config, fingerprint)
 				if err = utlsConn.BuildWebsocketHandshakeState(); err != nil {
 					return nil, fmt.Errorf("parse url %s error: %w", c.Path, err)
 				}
 				conn = utlsConn
 			}
 		} else {
-			conn = tls.Client(conn, c.TLSConfig)
+			conn = tls.Client(conn, config)
 		}
 
 		if tlsConn, ok := conn.(interface {
@@ -348,13 +363,6 @@ func streamWebsocketConn(ctx context.Context, conn net.Conn, c *WebsocketConfig,
 		}
 	}
 
-	uri := url.URL{
-		Scheme:   scheme,
-		Host:     net.JoinHostPort(c.Host, c.Port),
-		Path:     u.Path,
-		RawQuery: u.RawQuery,
-	}
-
 	request := &http.Request{
 		Method: http.MethodGet,
 		URL:    &uri,