Parse The Received Packet

struct iphdr* iphdr = NULL;
struct icmphdr* recv_icmphdr = NULL;

// we got an IP packet - verify that it contains an ICMP message.
iphdr = (struct iphdr*)rbuf;
if (iphdr->protocol != IPPROTO_ICMP) {
    fprintf(stderr, "Expected ICMP packet, got %u\n", iphdr->protocol);
    exit(1);
}

Originally written by guy keren