It's become clear that our network options are insufficient, with the coming
addition of Tor and unix domain support.
Currently:
1. We always bind to local IPv4 and IPv6 sockets, unless --port=0, --offline,
or any address is specified explicitly. If they're routable, we announce.
2. --addr is used to announce, but not to control binding.
After this change:
1. --port is deprecated.
2. --addr controls what we bind to and announce.
3. --bind-addr/--announce-addr can be used to control one and not the other.
4. Unless --autolisten=0, we add local IPv4 & IPv6 port 9735 (and announce if they are routable).
5. --offline still overrides listening (though announcing is still the same).
This means we can bind to as many ports/interfaces as we want, and for
special effects we can announce different things (eg. we're sitting
behind a port forward or a proxy).
What remains to implement is semi-automatic binding: we should be able
to say '--addr=0.0.0.0:9999' and have the address resolve at bind
time, or even '--addr=0.0.0.0:0' and have the port autoresolve too
(you could determine what it was from 'lightning-cli getinfo'.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
fe96fe10c7