Linux用ICMP协议达成简单Ping网络监测功能
发布时间:2021-11-23 15:59:06 所属栏目:教程 来源:互联网
导读:ICMP是(Internet Control Message Protocol)Internet控制报文协议。它是TCP/IP协议族的一个子协议,用于在IP主机、路由器之间传递控制消息。控制消息是指网络通不通、主机是否可达、路由是否可用等网络本身的消息。这些控制消息虽然并不传输用户数据,但是
ICMP是(Internet Control Message Protocol)Internet控制报文协议。它是TCP/IP协议族的一个子协议,用于在IP主机、路由器之间传递控制消息。控制消息是指网络通不通、主机是否可达、路由是否可用等网络本身的消息。这些控制消息虽然并不传输用户数据,但是对于用户数据的传递起着重要的作用。 ICMP协议是一种面向无连接的协议,用于传输出错报告控制信息。它是一个非常重要的协议,它对于网络安全具有极其重要的意义。 折腾半天,原来ICMP也是TCP/IP其中一种协议.那么监测网络是否ping的通,就跟TCP协议差不多了。 步骤简单归纳为:1.绑定套接字,2.发送数据包 3.接收数据包 4.解析数据包 #include <stdio.h> #include <sys/socket.h> #include <netinet/in.h> #include <netinet/ip.h> #include <netinet/ip_icmp.h> #include <netdb.h> #define PACKET_SIZE 4096 #define ERROR 0 #define SUCCESS 1 //效验算法(百度下有注释,但是还是看不太明白) unsigned short cal_chksum(unsigned short *addr, int len) { int nleft=len; int sum=0; unsigned short *w=addr; unsigned short answer=0; while(nleft > 1) { sum += *w++; nleft -= 2; } if( nleft == 1) { *(unsigned char *)(&answer) = *(unsigned char *)w; sum += answer; } sum = (sum >> 16) + (sum & 0xffff); sum += (sum >> 16); answer = ~sum; return answer; } // Ping函数 int ping( char *ips, int timeout) { struct timeval *tval; int maxfds = 0; fd_set readfds; struct sockaddr_in addr; struct sockaddr_in from; // 设定Ip信息 bzero(&addr,sizeof(addr)); addr.sin_family = AF_INET; addr.sin_addr.s_addr = inet_addr(ips); int sockfd; // 取得socket sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP); if (sockfd < 0) { printf("ip:%s,socket errorn",ips); return ERROR; } struct timeval timeo; // 设定TimeOut时间 timeo.tv_sec = timeout / 1000; timeo.tv_usec = timeout % 1000; if (setsockopt(sockfd, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo)) == -1) { printf("ip:%s,setsockopt errorn",ips); return ERROR; } char sendpacket[PACKET_SIZE]; char recvpacket[PACKET_SIZE]; // 设定Ping包 memset(sendpacket, 0, sizeof(sendpacket)); pid_t pid; // 取得PID,作为Ping的Sequence ID pid=getpid(); struct ip *iph; struct icmp *icmp; icmp=(struct icmp*)sendpacket; icmp->icmp_type=ICMP_ECHO; //回显请求 icmp->icmp_code=0; icmp->icmp_cksum=0; icmp->icmp_seq=0; icmp->icmp_id=pid; tval= (struct timeval *)icmp->icmp_data; gettimeofday(tval,NULL); icmp->icmp_cksum=cal_chksum((unsigned short *)icmp,sizeof(struct icmp)); //校验 int n; // 发包 n = sendto(sockfd, (char *)&sendpacket, sizeof(struct icmp), 0, (struct sockaddr *)&addr, sizeof(addr)); if (n < 1) { printf("ip:%s,sendto errorn",ips); return ERROR; } // 接受 // 由于可能接受到其他Ping的应答消息,所以这里要用循环 while(1) { // 设定TimeOut时间,这次才是真正起作用的 FD_ZERO(&readfds); FD_SET(sockfd, &readfds); maxfds = sockfd + 1; n = select(maxfds, &readfds, NULL, NULL, &timeo); if (n <= 0) { printf("ip:%s,Time out errorn",ips); close(sockfd); return ERROR; } // 接受 memset(recvpacket, 0, sizeof(recvpacket)); int fromlen = sizeof(from); n = recvfrom(sockfd, recvpacket, sizeof(recvpacket), 0, (struct sockaddr *)&from, (socklen_t *)&fromlen); if (n < 1) { break; } char *from_ip = (char *)inet_ntoa(from.sin_addr); // 判断是否是自己Ping的回复 if (strcmp(from_ip,ips) != 0) { printf("NowPingip:%s Fromip:%snNowPingip is not same to Fromip,so ping wrong!n",ips,from_ip); return ERROR; } iph = (struct ip *)recvpacket; icmp=(struct icmp *)(recvpacket + (iph->ip_hl<<2)); printf("ip:%sn,icmp->icmp_type:%dn,icmp->icmp_id:%dn",ips,icmp->icmp_type,icmp->icmp_id); // 判断Ping回复包的状态 if (icmp->icmp_type == ICMP_ECHOREPLY && icmp->icmp_id == pid) //ICMP_ECHOREPLY回显应答 { // 正常就退出循环 break; } else { // 否则继续等 continue; } } int main() { char cPing[16]; printf("Please input ping IP:"); scanf("%s",cPing); if(ping(cPing,10000)) { printf("Ping succeed!n"); } else { printf("Ping wrong!n"); } } 测试结果: root@an-virtual-machine:~/wyz/test# ./testping Please input ping IP:192.168.1.155 Nowip:192.168.1.155 Fromip:192.168.1.133 Nowip is not same to Fromip,so ping wrong! Ping wrong! root@an-virtual-machine:~/wyz/test# ./testping Please input ping IP:192.168.1.188 ip:192.168.1.188 ,icmp->icmp_type:0 ,icmp->icmp_id:27865 Ping succeed! (编辑:济南站长网) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |