From the README:

  This program is designed to log smurf attacks and the broadcasts used.
  Essentially it is just an icmp echo reply logger with the following twists:
   - Logging only begins after passing a certain threshold rate of packets/sec
     and kilobytes/sec. This prevents the logging of innocent ping replies.
   - Only the /24 is logged, and it is only logged once per attack.

Jacques Vidrine <nectar@FreeBSD.ORG>