OpenAAPD (0.1-beta) is an Anti Arp Poisoning Daemon for OpenBSD operating system which works with or without DHCP protocol support on the LAN networks without compromising the ARP protocol performances.
You can download it from the following link: https://packetstormsecurity.com/files/download/40103/aapd.c
Source: https://packetstormsecurity.com/files/40103/aapd.c.html