- "Record the peer" means
- 1. expire any peers last seen >120s ("mobile-peer-expiry") ago
- 2. add the peer of the just received packet to the applicable list
- (possibly evicting older entries)
- NB that we do not expire peers until an incoming packet arrives.
+ - We can't tell when local network setup changes so we can't cache
+ the unsupported addrs and completely remove the spurious calls to
+ sendto, but we can optimise things a bit by deprioritising addrs
+ which seem to be unsupported.
+
+ - Use only configured addresses. (Except, that if our peer
+ initiated a key exchange we use the incoming packet address until
+ our name resolution completes.)
+
+ - When we send a packet, try each address in turn; if addr
+ supported, put that address to the end of the list for future
+ packets, and go onto the next address.
+
+ - When we complete a key setup, we replace the data transport peers
+ with those from the key setup.