Network under ARP flood

my network is under discreet attacks with ARP packets. bcoz of this my switch mac address table is flooding, i tried increasing table size but of no use. Bcoz of this my network has gone slow, there are many packet drops, data transfer are less than half wat it used to be earlier. How can i prevent ARP attack? How do they burst so much ARP? can anybody gimme a source code of ARP flooder so that i can study it and prevent it from happening.