tomd socket protocol design specification

This documents the intended design of the protocol used by tomd and
its client applications.

Socket type:
We are using PF_LOCAL (protocol family local, IE unix sockets, bound
to files) sockets to facilitate communication. The libc implementation
is used, see the libc texinfo manual for details. This protocol family
was chosen because it offers the best performance locally, and there
is no current intention to allow for the daemon to be used remotely.

Datagram (udp packets) vs socket streams (byte streams):
With byte streams, I would need to delicately encode all of the
transitions between commands - however, it is much easier to keep the
clients individual, with separate accept calls per connection. with
datagrams we would need to encoded the sender, with callback
information to send status information on requests back to the
client. Weighing these pros and cons, I have gone with datagrams so
that the individual packets are easier to work with.