LinuxQuestions.org - ICMP Packet capture

I have managed to capture icmp packets using winpcap on windows .
Code:
#include <pcap.h>

void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data);

int main()

{

    pcap_if_t *alldevs;

    pcap_if_t *dev;

    int i=0;

    char errbuf[PCAP_ERRBUF_SIZE];

    bpf_u_int32 mask;

        bpf_u_int32 net;

        pcap_t *handle;

 struct bpf_program filter;

 char filter_app[] = "icmp";

 struct pcap_pkthdr header;

    /* Retrieve the device list */

    if (pcap_findalldevs(&alldevs, errbuf) == -1)

    {

        fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);

        exit(1);

    }

    

    /* Print the list */

    for(dev=alldevs;dev;dev=dev->next)

    {

        printf("%d. %s", ++i, dev->name);

        if (dev->description)

            printf(" \n (%s)\n", dev->description);

        else            printf(" (No description available)\n");

        pcap_lookupnet(dev->name, &net, &mask, errbuf);

        handle = pcap_open_live(dev->name, BUFSIZ, 1, 0, errbuf);

 pcap_compile(handle, &filter, filter_app, 0, net);

  pcap_setfilter(handle, &filter);

  printf("\n Sniffing %s::",dev->name);

 pcap_loop(handle, 0, packet_handler, NULL);

pcap_close(handle);

        }

    if(i==0)

    {

        printf("\nNo interfaces found! Make sure WinPcap is installed.\n");

        return 0;

    }

    /* We don't need any more the device list. Free it */

    pcap_freealldevs(alldevs);

        return 0;

}

void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data)

{

    struct tm *ltime;

    char timestr[16];

    /* convert the timestamp to readable format */

    ltime=localtime(&header->ts.tv_sec);

    strftime( timestr, sizeof timestr, "%H:%M:%S", ltime);

    printf(" \n %s,%.6d len:%d\n", timestr, header->ts.tv_usec, header->len);

}
Now I need to check if the request is for a ping . Can you please me as to how to do that ...