ping(1)

/*

ping program for learning IP protocol

    author: jeff
    date:    2014/10/25

*/

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>

static int ICMP_create();
static int opt_set(int sockfd);

int
main(int argc, char* argv[])
{
    int sockfd = ICMP_create();
    int optset = 0;
    if(sockfd != -1)
        printf("create socket ICMP success!\n");
    else
        printf("create socket ICMP failed [%d]!\n", errno);

    optset = opt_set(sockfd);
    if(optset != -1)
        printf("sock set success\n");
    else
        printf("sock set failed\n");

    return 0;
}

static int ICMP_create()
{
    return socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
}

static int opt_set(int sockfd)
{
    int on =1;
    return setsockopt(sockfd, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on));
}