socket

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

    char msg[300];

    int main()
    {

      char adr[] = "127.0.0.1";

      int fd=socket(PF_INET,SOCK_DGRAM,IPPROTO_ICMP);
      if (fd==-1) {
        return -1;
      }

      const size_t req_size=8;
      struct icmphdr req;
      req.type=8;
      req.code=0;
      req.checksum=0;
      req.un.echo.id=htons(12);
      req.un.echo.sequence=htons(1);

      struct sockaddr_in sin;
      sin.sin_family = AF_INET;
      sin.sin_addr.s_addr = inet_addr (adr);

      if (sendto(fd,&req,req_size,0,
        (struct sockaddr *) &sin,sizeof(sin))==-1) {
        return -1;
      }


      int  n = recv(fd, msg, sizeof(msg), 0);
      if(n <= 0) {
        printf("recv fail\n");
        return -1;
      }


      struct icmphdr rcv_hdr;
      memcpy(&rcv_hdr, msg, sizeof rcv_hdr);
      if (rcv_hdr.type == ICMP_ECHOREPLY) {
        printf("ICMP Reply, id=0x%x, sequence =  0x%x\n",
            rcv_hdr.un.echo.id, rcv_hdr.un.echo.sequence);
      } else {
        printf("Got ICMP packet with type 0x%x ?!?\n", rcv_hdr.type);
      }

      return 0;
    }





    Program output:
    $ ./test
    ICMP Reply, id=0x400, sequence =  0x100



    Tcpdump output:
    $ sudo tcpdump -i lo -X -v icmp
    tcpdump: listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes
    15:13:55.398941 IP (tos 0x0, ttl 64, id 37644, offset 0, flags [DF], proto ICMP (1), length 28)
        localhost > localhost: ICMP echo request, id 4, seq 1, length 8
            0x0000:  4500 001c 930c 4000 4001 a9d2 7f00 0001  E.....@.@.......
            0x0010:  7f00 0001 0800 f7fa 0004 0001            ............
    15:13:55.398958 IP (tos 0x0, ttl 64, id 37645, offset 0, flags [none], proto ICMP (1), length 28)
        localhost > localhost: ICMP echo reply, id 4, seq 1, length 8
            0x0000:  4500 001c 930d 0000 4001 e9d1 7f00 0001  E.......@.......
            0x0010:  7f00 0001 0000 fffa 0004 0001            ............