Joinmarket bots run their own onion services allowing inbound connections.
Both takers and makers connect to other makers at the mentioned
onion services, over Tor.
Directory nodes run persistent onion services allowing peers to
find other (maker) peers to connect to, and also forwarding
messages where necessary.
This is implemented as an alternative to IRC, i.e. a new
implementation of the abstract class MessageChannel, in onionmc.py.
Note that using both this *and* IRC servers is supported; Joinmarket
supports multiple, redundant different communication methods,
simultaneously.
Messaging is done with a derived class of twisted's LineReceiver,
and there is an additional layer of syntax, similar to but not the
same as the IRC syntax for ensuring that messages are passed with
the same J5.. nick as is used on IRC. This allows us to keep the
message signing logic the same as before. As well as Joinmarket line
messages, we use additional control messages to communicate peer lists,
and to manage connections.
Peers which send messages not conforming to the syntax are dropped.
See https://github.com/JoinMarket-Org/JoinMarket-Docs/pull/12 for
documentation of the syntax.
Connections to directory nodes are robust as for IRC servers, in
that we use a ReconnectingClientFactory to keep trying to re-establish
broken connections with exponential backoff. Connections to maker
peers do not require this feature, as they will often disconnect
in normal operation.
Multiple directory nodes can and should be configured by bots.