说明：  本实验要求充分理解RIP协议，根据RIP协议的流程设计RIP协议的报文处理和超时处理函数，并实现如下功能：RIP报文有效性检查；处理Request报文；处理Response报文；路由表项超时删除；路由表项定时发送。
(In this study, the agreement calls for the full understanding of RIP, the agreement under the RIP process design RIP protocol packet processing and time-out processing functions, and to achieve the following functions: RIP packet validity checks processing Request packet processing Response message routing table entry timeout deleted routing table entry from time to time to send.)