Finally I added another library
https://github.com/JImmyFrasche/etsn/tree/master/etsnunix that
provides a convenient method for registering protocols with etsnsrv(1)
with an interface somewhat like a pared down version of etsn.
Like I said, I just made sure it compiled so it probably doesn't work
right, if at all—and I know there are a few places where it does
outright obviously the wrong thing—but should serve as a sketch, till
I knock the bugs off it and get a better idea of where to tidy it up.
Perhaps the protocol, or lack of one, is too simplistic, but no reason
not to try the simplest possible solution first.
