#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

#include <netinet/ip.h>
#include <netinet/ip_icmp.h>

int main(){
     int sockfd,retval,n;
     socklen_t clilen;
     struct sockaddr_in cliaddr, servaddr;
     char buf[10000]; 
     int i;
     
     sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
     if (sockfd < 0){
          perror("sock:");
          exit(1);
     }
     clilen = sizeof(struct sockaddr_in);    
     while(1){
          printf(" before recvfrom\n");   
          n=recvfrom(sockfd, buf, 10000, 0, (struct sockaddr *)&cliaddr, &clilen);
          printf(" rec'd %d bytes\n",n);
          
          struct iphdr *ip_hdr = (struct iphdr *)buf;
          
          printf("IP header is %d bytes.\n", ip_hdr->ihl*4);
          
          for (i = 0; i < n; i++) {
               printf("%02X%s", (uint8_t)buf[i], (i + 1)%16 ? " " : "\n");
          }
          printf("\n");
          
          struct icmphdr *icmp_hdr = (struct icmphdr *)((char *)ip_hdr + (4 * ip_hdr->ihl));
          
          printf("ICMP msgtype=%d, code=%d", icmp_hdr->type, icmp_hdr->code);
     }
}