Similar to assign_vips() used by a peer assigning virtual IPs to the other peer,
the handle_vips() hook gets invoked on a peers after receiving attributes. On
release of the same attributes the hook gets invoked again.
This is useful to inspect handled attributes, as the ike_updown() hook is
invoked after authentication, when attributes have not been handled yet.
The new interface does not allow loggers to unregister themselves from
the bus. This allows us to use a rwlock_t for them.
The latter also means that loggers can now be called concurrently by
multiple threads.
This avoids deadlocks caused by extensive listener_t implementations
which might want to acquire a lock which is currently held by another
thread wanting to log messages. Since the latter requires that thread
to acquire the same lock the initial thread currently holds this
previously resulted in a deadlock.
With this change logging messages does not require threads to acquire
the main lock in bus_t and thus avoids the deadlock.
Martin Willi