(usagi-users 03388) Re: MLDv2 linux implementation questions

Thanks to you, I actually can't do this because I'm joining a dynamic
set of (S,G), (S1,G),(S2,G), ...(Sn,G) channels, so leaving all the G group
would cancel all the trafic coming from others sources, which is not what I
want.

Hoerdt Mickaël

David Stevens wrote:

>Hoerdt,
>        Thanks for the program, I've reproduced the problem, and
>it appears to be a long-standing bug in the multicast code. Using
>source filters just makes it happen sooner.
>        I'll work on a patch to fix this issue; in the meantime, you
>can avoid it by doing a regular "leave group" on the group
>address, rather than the delta-based MCAST_LEAVE_SOURCE_GROUP,
>which will not delete the existing membership.
>
>                                +-DLS
>
>gory details, if you're interested:
>        The "join" code does not check if you have already
>joined the same group on that socket, but allocates a new
>multicast structure (and filter too, in your case) for every join.
>The "leave"'s you're doing delete the source filter entry, but
>do not delete the multicast group membership, only add an
>"INCLUDE,empty" filter.
>        So, each iteration allocates a new multicast group
>structure and source filter associated with the socket, until
>you run out of  space.
>        Fix should be to check if the socket is already a member
>of the group and don't allocate a new multicast address
>structure if it is.
>        Pre-MLDv2, a series of joins would result in the
>same problem, but would've taken longer since there is
>no source filter allocation to go with the multicast structures
>it is allocating.
>
>
>  
>