Re: [PATCH RFC net-next 00/10] MC Flood disable and snooping

[Vladimir Oltean]

Hi Nikolai,

On Tue, Apr 02, 2024 at 12:28:38PM +0300, Nikolay Aleksandrov wrote:
> For the bridge patches:
> Nacked-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>
> 
> You cannot break the multicast flood flag to add support for a custom
> use-case. This is unacceptable. The current bridge behaviour is correct
> your patch 02 doesn't fix anything, you should configure the bridge
> properly to avoid all those problems, not break protocols.
> 
> Your special use case can easily be solved by a user-space helper or
> eBPF and nftables. You can set the mcast flood flag and bypass the
> bridge for these packets. I basically said the same in 2021, if this is
> going to be in the bridge it should be hidden behind an option that is
> default off. But in my opinion adding an option to solve such special
> cases is undesirable, they can be easily solved with what's currently
> available.

I appreciate your time is limited, but could you please translate your
suggestion, and detail your proposed alternative a bit, for those of us
who are not very familiar with IP multicast snooping?

Bypass the bridge for which packets? General IGMP/MLD queries? Wouldn't
that break snooping? And then do what with the packets, forward them in
another software layer than the bridge?

I also don't quite understand the suggestion of turning on mcast flooding:
isn't Joseph saying that he wants it off for the unregistered multicast
data traffic?