Message rebroadcast hours later

[gvelez17]

While investigating a Pubsub Flood: https://github.com/libp2p/go-libp2p-pubsub/issues/524 in which the same sequence number appears multiple times, we have seen cases where the same From and Seqno appear as much as 6 hours apart.

This exceeds most reasonable cache sizes. Is there a way to prevent this behavior?

[vyzo]

We recently introduced default validators with an implementation that rejects old sequence numbers.

It can be improved (planned follow up to use a sack bitfield for tracking the last 64 msgs), but it can solve your problem.