implement statuscode in packets

tcp-cart-mux-server.go

@@ -69,13 +69,24 @@ func (m *TCPCartServerMux) handleFunction(connection net.Conn, messageType uint3
 	m.mu.RUnlock()
 	if ok {
 		responseType, responseData, err := fn(id, data)
+
 		if err != nil {
+			errData := []byte(err.Error())
+			err = binary.Write(connection, binary.LittleEndian, CartPacket{
+				Version:     CurrentPacketVersion,
+				MessageType: responseType,
+				DataLength:  uint32(len(errData)),
+				StatusCode:  500,
+				Id:          id,
+			})
+			_, err = connection.Write(errData)
 			return true, err
 		}
 		err = binary.Write(connection, binary.LittleEndian, CartPacket{
 			Version:     CurrentPacketVersion,
 			MessageType: responseType,
-			DataLength:  uint64(len(responseData)),
+			DataLength:  uint32(len(responseData)),
+			StatusCode:  200,
 			Id:          id,
 		})
 		if err != nil {
@@ -101,7 +112,10 @@ func (m *TCPCartServerMux) HandleConnection(connection net.Conn) error {
 			log.Printf("Error receiving packet: %v\n", err)
 			return err
 		}
-
+		if packet.Version != CurrentPacketVersion {
+			log.Printf("Incorrect packet version: %d\n", packet.Version)
+			continue
+		}
 		data, err := GetPacketData(connection, packet.DataLength)
 		if err != nil {
 			log.Printf("Error getting packet data: %v\n", err)