void my_callback(u_char *args,const struct pcap_pkthdr *hdr, const u_char *packet){
uint16_t type = handle_ethernet(args,hdr,packet);
uint16_t ipproto = -1;
uint16_t pld_l =0;
printf("type eth: %d\n",type);
if(type == ETHERTYPE_IP){
ipproto = handle_IP(args,hdr,packet);
} else if (type == ETHERTYPE_ARP) {
printf("ARP\n");
}
if(ipproto == 17)
pld_l = handle_UDP(args,hdr,packet);
else if(ipproto == 6){
//pld_l = handle_TCP(args,hdr,packet);
}
printf("length pld: %d\n",pld_l);
if(pld_l > 0)
handle_PLD(args,hdr,packet);
}
u_char* handle_IP
(u_char *args,const struct pcap_pkthdr* pkthdr,const u_char*
packet)
{
const struct my_ip* ip;
u_int length = pkthdr->len;
u_int hlen,off,version;
int i;
int len;
/* jump pass the ethernet header */
ip = (struct my_ip*)(packet + sizeof(struct ether_header));
length -= sizeof(struct ether_header);
/* check to see we have a packet of valid length */
if (length < sizeof(struct my_ip))
{
fprintf(stderr, "!");
return NULL;
}
len = ntohs(ip->ip_len);
hlen = IP_HL(ip); /* header length */
version = IP_V(ip);/* ip version */
/* check version */
if(version != 4)
{
fprintf(stdout,"Unknown version %d\n",version);
return NULL;
}
/* check header length */
if(hlen < 5 )
{
fprintf(stdout,"bad-hlen %d \n",hlen);
}
/* see if we have as much packet as we should */
if(length < len)
printf("\ntruncated IP - %d bytes missing\n",len - length);
/* Check to see if we have the first fragment */
off = ntohs(ip->ip_off);
if((off & 0x1fff) == 0 )/* aka no 1's in first 13 bits */
{/* print SOURCE DESTINATION hlen version len offset */
fprintf(stdout, "%5d ", pkt_count);
switch (ip->ip_p) {
case 1:
fprintf(stdout, "ICMP");
break;
case 6:
fprintf(stdout, "TCP");
break;
case 17:
fprintf(stdout, "UDP");
break;
case 41:
fprintf(stdout, "IPv6");
break;
case 47:
fprintf(stdout, "GRE");
break;
case 50:
fprintf(stdout, "ESP");
break;
default:
fprintf(stdout, "UNKNOWN (%d)", ip->ip_p);
break;
}
fprintf(stdout,":\t%s\t%s",
inet_ntoa(ip->ip_src),
inet_ntoa(ip->ip_dst));
// fprintf(stdout,"\tlen= %3d hlen = %3d", len, hlen);
switch (ip->ip_p) {
case 6:
handle_TCP(args, pkthdr, packet + sizeof(struct ether_header) + (hlen * 4), len - (hlen * 4));
break;
case 17:
handle_UDP(args, pkthdr, packet + sizeof(struct ether_header) + (hlen * 4));
break;
default:
fprintf(stdout, "\n");
break;
}
}
return NULL;
}
