Add API to allow/disallow specific multicast destinations
Submitted by Patricia Muscalu
The current implementation relies on the address pool:
the server checks if the suggested destination/port is present in the pool and reserves the address (doing that, no other clients are allowed to request the same multicast group, which is not correct, see the discussion in https://bugzilla.gnome.org/show_bug.cgi?id=793441).
Probably, the pre-configured address pool should be only involved in choosing the server-selected address/port pairs. Thus we would need an additional security step for checking if the the destination suggested by the client is allowed.