i once needed this, but didn't want to release it. now it doesn't
matter. hope some of the code can be useful to the right people.

you will need a lot of large listening routes, and fast scan sources
(e.g. at a major IX) not subject to upstream uRPF. the point was to
reduce the temporal / spatial locality of sources / targets in a scan.

yes, the scans are lossy. this wasn't built for accuracy, but for
large scale results.

-d.