说明：  这是我课程设计的一个程序,程序实现echo request icmp 的发送和echo reply icmp 的接收,以发现网络中在线主机以及测量与其他主机的平均往返时间
(This is my curriculum design a procedure, Program icmp echo request and send the reply icmp echo reception, to detect network and host online measurement and other hosts of the average journey time)