inline u_int32_t hash_function(const u_char *packet, int pkt_len) 
{
  u_int32_t hash=0;
  u_int8_t next_protocol;
  u_int32_t src_ip,dst_ip;  
  u_short  src_p,dst_p;       
  
  
  unsigned short ip_hdr_len;
  
      // Checking if it is a IPv4 or IPv6 packet
    struct ether_header *eptr;  /* net/ethernet.h */
    eptr = (struct ether_header *) packet;

    if (ntohs (eptr->ether_type) == ETHERTYPE_IP) // means it is IPv4 pkt
        {
            struct iphdr *ip4h = (struct iphdr *)(packet  + sizeof(struct ethhdr) );
        ip_hdr_len =ip4h->ihl*4;
        next_protocol=ip4h->protocol;
        pktFeatures.src_ip=ntohl(ip4h->saddr);
        pktFeatures.dst_ip=ntohl(ip4h->daddr);
        pktFeatures.pkt_len=pkt_len;
        switch (next_protocol) //Check the Protocol and do accordingly...
        {
        case 6:  //TCP Protocol
               {
                struct tcphdr *tcph=(struct tcphdr*)(packet + ip_hdr_len + sizeof(struct ethhdr));
                pktFeatures.src_p=ntohs(tcph->th_sport);
                pktFeatures.dst_p=ntohs(tcph->th_dport);
                pktFeatures.protocol=next_protocol;
                writeBytes((char *)&pktFeatures,sizeof(struct packet_features),WRITE_TO_FILE);
            }
            break;
        case 17: //UDP Protocol
            {
                struct udphdr *udph = (struct udphdr*)(packet + ip_hdr_len  + sizeof(struct ethhdr));
                pktFeatures.src_p=ntohs(udph->uh_sport);
                pktFeatures.dst_p=ntohs(udph->uh_sport);
                pktFeatures.protocol=next_protocol;
                writeBytes((char *)&pktFeatures,sizeof(struct packet_features),WRITE_TO_FILE);                 
            }
            break;
        default: //Some Other Protocol like ARP FTP etc.
            {
                printf(" * Some Other Protocol \n");
                            
            }
        }
        int rm=0;
        }/*else  if (ntohs (eptr->ether_type) == ETHERTYPE_IPV6) // means it is IPv6 pkt
            {
                
            u_int32_t *s, *d;
            struct ip6_hdr *ip6h = (struct ip6_hdr *)(packet  + sizeof(struct ethhdr) );
            ip_hdr_len=320;
            next_protocol=ip6h->ip6_un1_nxt; // is the next protocol type
            s = (u_int32_t *) &ip6h->ip6_src, d = (u_int32_t *) &ip6h->ip6_dst;
            hash=(s[0] + s[1] + s[2] + s[3] + d[0] + d[1] + d[2] + d[3]+ip6h->ip6_un1_nxt); // ip6_un1_nxt is the next protocol                                         type TCP/UDP can be extention header ? need to be catered for
             
            }else hash=0;
         */
         
 return hash;

}