Instead of a linear array which is fairly inefficient if it turns out
we know nothing at all.
We remove the gossip_missing() call by changing the api to
remove_unknown_scid() to include a flag as to whether the scid turned
out to be real or not.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Once we've finished streaming gossip from the first peer, we ask a
random peer (maybe the same one) for all short_channel_ids in the last
6 blocks from the latest channel we know about.
If this reveals new channels we didn't know about, we expand the probe
by a factor of 2 each time.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The seeker starts by asking a peer (the first peer!) for all gossip
since a minute before the modified time of the gossip store.
This algorithm is enhanced in successive patches.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
