说明：  本程序只对一个IP地址进行，如果要对一段IP进行测试，简单修改程序即可。可将发送放在单独的进程 里(使用fork（）），send_icmp里做成循环，每次重新初始化struct sockaddr_in。那么对接收到的数据 进行分析的proc_icmp（）将多一道对IP报头ip->src字段的判断。
(this procedure only a pair of IP addresses, IP to a test, a simple change procedures. This can be placed on a separate process (the use of fork ()), causing Lane send_icmp cycle, each re-initialization struct sockaddr_in. Then Butt received the data analysis proc_icmp () will more than one pair of IP header ip-gt; Src field judgment.)