Re: [B.A.T.M.A.N.] [PATCHv5 0/3] batman-adv: Unicasting multicast reports to querier-node only

["Linus Lüssing" <linus.luessing@c0d3.blue>]

PS: If you like the new compat solution better, then please let me
know what copyright header you'd like to have added.

Currently only compat-sources/net/ipv6/mcast_snoop.c has a header,
identical to the one in the upstream kernel. For the other files
I'm a little unsure about what to add. For instance
compat-sources/net/ipv4/igmp.c is a lot based on Herbert Xu's
work (similar to how mcast_snoop.c is based on Yoshifuji's work).


On Wed, May 06, 2015 at 09:29:19PM +0200, Linus Lüssing wrote:
> The last round of multicast patches send to the batman-adv mailinglist
> to add support for the multicast optimizations in bridged scenarios, too,
> unfortunately had one major conceptual flaw: It could lead to packet loss.
> It's not sufficient to have the unicasting of reports implemented on
> bridge-nodes only. Nodes without bridges need to treat reports the same
> way.
> 
> The issue is described in detail here:
> 
> https://www.open-mesh.org/projects/batman-adv/wiki/Multicast-optimizations-listener-reports
> 
> 
> Cheers, Linus
> 
> -----
> 
> Changelog:
> v5:
>  * Removed RFC tag: Needed exports got merged to net-next and are going to
>    be available with Linux 4.2
>  * Redid compat solution - now fully backwards compatible down to 2.6.33
> v4:
>  * excluded bridge part from this patchset, they should
>    hopefully be added to net-next soon
>  * Added a compat solution (PATCH 3/3)
>  * Removed Kconfig-depends as by David's suggestion the needed parsing
>    functions for MLD are going to be forced built-ins even if IPv6 is
>    going to be built as a module
>  * Removed unused variable 'int ret' in batadv_mcast_is_report_ipv6()
>  * Adjusted to new folder structure
> v3:
>  * Adding Kconfig-depends and #if's
>    (so basically adding similar dependancy constraints as the bridge code
>     has, except that there are no depends if batman-adv gets compiled without
>     multicast optimizations)
>    -> the case of IPv6=M and batman-adv=y is still impossible if multicast
>       optimizations are enabled; but I don't see the practical demand for that
>       either - people who use IPv6 as a module will probably also want to
>       use batman-adv as a module
> v2:
>  * various bugfixes (now runtime tested, too - should(tm) work)
>  * added netdev+bridge mailinglists