Gossip Observer: New project to monitor the Lightning P2P network

[rustyrussell]

@jonhbit

IIUC, the sketch decode has multiple steps, and most of the compute is in the final step. Before that final step, a decoder would know if decode is expected to yield a successful reconciliation with very high probability, before executing that final step. So an early exit should make the cost for that much smaller; I think this isn’t yet implemented in the minisketch library though.

That API would be great, but meanwhile I think you just trim untrusted sources to use a small sketch, which bounds the time. If a failure to decode simply (eventually) results in you streaming all gossip, it’s no worse than the current case where a peer explicitly asks you for all gossip?