>> 	i ran some experiment with IPv6, and now I think in_pcbpurgeif() is
>> 	incorrect.  it should not leave multicast groups the user application
>> 	have joined.
>It would be arguable, but probably what we should do is either:
>	(1) leave and somehow tell an application so.
>or
>	(2) re-join automatically somehow.
>For (1), how to tell would be a matter.  For (2), how to select an
>interface would be a matter.  Using an address which an application is
>used to specify interface?  If so, we should join using another
>interface if the address is moved to from a interface to another?

	yup.  (2) has another issue in IPv6 case, where all multicast
	address needs to come with scope zone identification, which is
	the interface index at this moment (as we do not reuse interface
	index, we need to update it)

	this is definitely a post-1.5 item, just to be sure.

itojun