      def proxy(client, mongo)
        incoming_message = client.read(16)
        length, op_code = incoming_message.unpack("l<x8l<")
        incoming_message << client.read(length - 16)

        if op_code == OP_QUERY && ismaster_command?(incoming_message)
          # Intercept the ismaster command and send our own reply.
          client.write status_reply
        else
          # This is a normal command, so proxy it to the real mongo instance.
          mongo.write incoming_message

          if op_code == OP_QUERY || op_code == OP_GETMORE
            outgoing_message = mongo.read(4)
            length, = outgoing_message.unpack('l<')
            outgoing_message << mongo.read(length - 4)

            client.write outgoing_message
          end
        end
      end
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.