int test_sketch(char* sketch_type, unsigned buckets, unsigned rows,
char* random_generator, char* hash_function,
char* pcap_file){
unsigned int pkt_counter=0; // packet counter
clock_t t1, t2, t3;
//temporary packet buffers
struct pcap_pkthdr header; // The header that pcap gives us
const u_char *packet; // The actual packet
// Create the sketch as the type passed as parameter
Sketch<KeyType>* sketch = get_sketch<KeyType>(sketch_type, buckets, rows,
random_generator, hash_function);
if (sketch == NULL) {
return -1;
}
//-----------------
//open the pcap file
pcap_t *handle;
char errbuf[PCAP_ERRBUF_SIZE];
handle = pcap_open_offline(pcap_file, errbuf); //call pcap library function
if (handle == NULL) {
fprintf(stderr,"Couldn't open pcap file %s: %s\n", pcap_file, errbuf);
return -1;
}
//-----------------
//Process one packet at a time
while (packet = pcap_next(handle,&header)) {
t1 = clock();
// header contains information about the packet (e.g. timestamp)
u_char *pkt_ptr = (u_char *)packet; //cast a pointer to the packet data
//parse the first (ethernet) header, grabbing the type field
int ether_type = ((int)(pkt_ptr[12]) << 8) | (int)pkt_ptr[13];
int ether_offset = 0;
if (ether_type == ETHER_TYPE_IP or ether_type == ETHER_TYPE_IPv6) //most common
ether_offset = 14;
else {
fprintf(stderr, "Unknown ethernet type, %04X, skipping...\n", ether_type);
continue;
}
// Only from IP header:
pkt_ptr += ether_offset; //skip past the Ethernet II header
int packet_length = header.len-ether_offset;
// Compute MD5
unsigned char * tmp_hash;
tmp_hash = MD5(pkt_ptr, packet_length, NULL);
// Strip to the size of the sketch:
uint64_t low_hash = low_md5(tmp_hash);
// Update sketch
t2 = clock();
sketch->update(low_hash,1);
t3 = clock();
printf("%s,%u,%u,%u,%s,%s,%f,%f,%f,%f\n",
sketch_type,
sizeof(KeyType),
buckets,
rows,
random_generator,
hash_function,
((float)t1)/CLOCKS_PER_SEC,
((float)t2)/CLOCKS_PER_SEC,
((float)t3)/CLOCKS_PER_SEC,
((float)t3-t1)/CLOCKS_PER_SEC);
pkt_counter++; //increment number of packets seen
if (pkt_counter >= 1000)
break;
} //end internal loop for reading packets (all in one file)
pcap_close(handle); //close the pcap file
return 0; //done
}
