Coexistence of multiple babel daemons on the same host

[Daniel Gröber]

Hi Babelers,

I've just come across a reason I'd want to run babel with both bird and
babeld on the same node and have them become neighbours. The details are
tedious -- my usual disclamer applies ;)

This got me to think about something I'd observed in the past and been
meaning to write about though: when I accidentally had both babeld and bird
running on a node it would casuse severe route flapping and consequently
packet loss.

I wonder if we can do better here? Maybe by warning about this situation in
the logs, shutting down both sides or just turning this into a supported
use-case? :)

>From what I gather by a quick skimming of the relevant details in RFC8966
this could work by assigning each daemon a unique LL address so each gets
it's own entry in the neighbour table, right?

Thanks,
--Daniel