makefile文件:
all:ping.c
gcc -o ping ping.c -lpthread
chmod u+s ping

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netdb.h>
#include <setjmp.h>
#include <errno.h>

#include <linux/if.h>

#define PACKET_SIZE     4096
#define MAX_WAIT_TIME   5
#define MAX_NO_PACKETS  100000

char sendpacket[PACKET_SIZE];
char recvpacket[PACKET_SIZE];
static int sockfd,datalen=56;
static int nsend=0,nreceived=0;
static struct sockaddr_in dest_addr;
pid_t pid;
struct sockaddr_in from;
struct timeval tvrecv;

pthread_t send_thread;
void statistics(int signo);
unsigned short cal_chksum(unsigned short *addr,int len);
static int pack(int pack_no);
void send_packet(void);
void recv_packet(void);
int unpack(char *buf,int len);
void tv_sub(struct timeval *out,struct timeval *in);
int stop = 0;
void statistics(int signo){
stop = 1;
printf("/n--------------------PING statistics-------------------/n");
printf("%d packets transmitted, %d received , %%%d lost/n",nsend,nreceived,
(nsend-nreceived)/nsend*100);
pthread_join(send_thread, NULL);
close(sockfd);
exit(1);
}

/*校验和算法*/
unsigned short cal_chksum(unsigned short *addr,int len){
int nleft=len;
int sum=0;
unsigned short *w=addr;
unsigned short answer=0;
       
/*把ICMP报头二进制数据以2字节为单位累加起来*/
while(nleft>1){
sum+=*w++;
nleft-=2;
}
/*若ICMP报头为奇数个字节，会剩下最后一字节。把最后一个字节视为一个2字节数据的高字节，这个2字节数据的低字节为0，继续累加*/
if( nleft==1){
*(unsigned char *)(&answer)=*(unsigned char *)w;
sum+=answer;
}
sum=(sum>>16)+(sum&0xffff);
sum+=(sum>>16);
answer=~sum;
return answer;
}

/*设置ICMP报头*/
static int pack(int pack_no){
int i,packsize;
struct icmp *icmp;
struct timeval *tval;

icmp=(struct icmp*)sendpacket;
icmp->icmp_type=ICMP_ECHO;
icmp->icmp_code=0;
icmp->icmp_cksum=0;
icmp->icmp_seq=pack_no;
icmp->icmp_id=pid;
packsize=8+datalen;
tval= (struct timeval *)icmp->icmp_data;
gettimeofday(tval,NULL);    /*记录发送时间*/
icmp->icmp_cksum=cal_chksum( (unsigned short *)icmp,packsize); /*校验算法*/

return packsize;
}

/*发送三个ICMP报文*/
void send_packet(){
int packetsize;
while((nsend<MAX_NO_PACKETS) &&
(!stop)){
nsend++;
packetsize=pack(nsend); /*设置ICMP报头*/
if( sendto(sockfd,sendpacket,packetsize,0,
(struct sockaddr *)&dest_addr,sizeof(dest_addr) )<0 ){
perror("sendto error");
continue;
}
sleep(1); /*每隔一秒发送一个ICMP报文*/
}
}

/*接收所有ICMP报文*/
void recv_packet(){
int n,fromlen;
extern int errno;
signal(SIGALRM,statistics);
fromlen=sizeof(from);
while((nreceived<MAX_NO_PACKETS) &&
(!stop)){
alarm(MAX_WAIT_TIME);
if( (n=recvfrom(sockfd,recvpacket,sizeof(recvpacket),0,
(struct sockaddr *)&from,&fromlen)) <0){
if(errno==EINTR){
continue;
}
perror("recvfrom error");
continue;
}
gettimeofday(&tvrecv,NULL); /*记录接收时间*/
if(unpack(recvpacket,n)==-1){
continue;
}
nreceived++;
}

}
/*剥去ICMP报头*/
int unpack(char *buf,int len){
int i,iphdrlen;
struct ip *ip;
struct icmp *icmp;
struct timeval *tvsend;
double rtt;

ip=(struct ip *)buf;
iphdrlen=ip->ip_hl<<2;    /*求ip报头长度,即ip报头的长度标志乘4*/
icmp=(struct icmp *)(buf+iphdrlen); /*越过ip报头,指向ICMP报头*/
len-=iphdrlen;            /*ICMP报头及ICMP数据报的总长度*/
if( len<8){                /*小于ICMP报头长度则不合理*/
printf("ICMP packets/'s length is less than 8/n");
return -1;
}
/*确保所接收的是我所发的的ICMP的回应*/
if ((icmp->icmp_type==ICMP_ECHOREPLY) && (icmp->icmp_id==pid) ){
tvsend=(struct timeval *)icmp->icmp_data;
tv_sub(&tvrecv,tvsend); /*接收和发送的时间差*/
rtt=tvrecv.tv_sec*1000+tvrecv.tv_usec/1000; /*以毫秒为单位计算rtt*/
/*显示相关信息*/
printf("%d byte from %s: icmp_seq=%u ttl=%d rtt=%.3f ms/n",
len,
inet_ntoa(from.sin_addr),
icmp->icmp_seq,
ip->ip_ttl,
rtt);
}else{
return -1;
}
}

int main(int argc,char *argv[]){      
struct hostent *host;
struct protoent *protocol;
unsigned long inaddr=0l;
int waittime=MAX_WAIT_TIME;
int size=50*1024;
struct ifreq interface;

if(argc<3){
printf("usage:%s hostname/IP address/n",argv[0]);
exit(1);
}

if( (protocol=getprotobyname("icmp") )==NULL){
perror("getprotobyname");
exit(1);
}
/*生成使用ICMP的原始套接字,这种套接字只有root才能生成*/
if( (sockfd=socket(AF_INET,SOCK_RAW,protocol->p_proto) )<0){
perror("socket error");
exit(1);
}
printf("ifname:%s/n",argv[2]);
strncpy(interface.ifr_ifrn.ifrn_name, argv[2], IFNAMSIZ);
if (setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, (char *)&interface, sizeof(interface)) < 0) {
printf("SO_BINDTODEVICE failed");
exit(1);
}

/* 回收root权限,设置当前用户权限*/
setuid(getuid());
/*扩大套接字接收缓冲区到50K这样做主要为了减小接收缓冲区溢出的
  的可能性,若无意中ping一个广播地址或多播地址,将会引来大量应答*/
setsockopt(sockfd,SOL_SOCKET,SO_RCVBUF,&size,sizeof(size) );
bzero(&dest_addr,sizeof(dest_addr));
dest_addr.sin_family=AF_INET;
/*判断是主机名还是ip地址*/
if( inaddr=inet_addr(argv[1])==INADDR_NONE){
if((host=gethostbyname(argv[1]) )==NULL){ /*是主机名*/
perror("gethostbyname error");
exit(1);
}
memcpy( (char *)&dest_addr.sin_addr,host->h_addr,host->h_length);
}else{    /*是ip地址*/
struct in_addr ip_addr;
ip_addr.s_addr = inet_addr(argv[1]);
dest_addr.sin_addr  = ip_addr;
}
/*获取main的进程id,用于设置ICMP的标志符*/
pid=getpid();
printf("PING %s(%s): %d bytes data in ICMP packets./n",argv[1],
inet_ntoa(dest_addr.sin_addr),datalen);
signal(SIGTERM, statistics);
signal(SIGINT, statistics);
signal(SIGABRT, statistics);
signal(SIGQUIT, statistics);
signal(SIGKILL, statistics);
/*发送所有ICMP报文*/
if (pthread_create(&send_thread, NULL, (void*)send_packet, NULL) != 0) {
printf("Create send thread failed./n");
exit(1);
}
recv_packet();
//statistics(SIGALRM); /*进行统计*/

return 0;

}

/*两个timeval结构相减*/
void tv_sub(struct timeval *out,struct timeval *in){
if( (out->tv_usec-=in->tv_usec)<0){
--out->tv_sec;
out->tv_usec+=1000000;
}
out->tv_sec-=in->tv_sec;
}