This is a fair amount of code, but much is taken from
the old routing.c, with the difference that this uses
common/gossmap instead of our own structures.
The interfaces are fairly clear:
1. gossmap_manage_new - allocator
2. gossmap_manage_channel_announcement
- handle new channel announcement msg
- if too early, keeps it in early map
- queues it, asks lightingd about UTXO.
3. gossmap_manage_handle_get_txout_reply
- handle response from lightningd for above.
4. gossmap_manage_channel_update
- handle channel_update message
- may have to wait on pending channel_announcement
5. gossmap_manage_node_announcement
- handle node_announcement msg
- may have to wait on pending channel_announcement
6. gossmap_manage_new_block
- see if early announces can now be processed.
7. gossmap_manage_channel_spent
- lightningd tells us UTXO is spent
- may prepare channel for closing in 12 blocks.
8. gossmap_manage_channel_dying
- gossip_store load tells us channel was spent earlier.
- like gossmap_manage_channel_spent, but maybe < 12.
9. gossmap_manage_get_gossmap
- gossmap accessor: seeker and queries will need this.
10. gossmap_manage_new_peer
- a new peer has connected, give them all our gossip.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
