[Bridge] [PATCH net-next 3/4] bridge: Consider the Nearest Customer Bridge group addresses

Stephen Hemminger stephen at networkplumber.org
Tue Jun 10 16:21:27 UTC 2014

On Tue, 10 Jun 2014 16:05:07 +0900
Toshiaki Makita <makita.toshiaki at lab.ntt.co.jp> wrote:

> (2014/06/10 7:33), Vlad Yasevich wrote:
> ...
> >>> Rather than special casing this around vlan filtering, I would prefer
> >>> the code always forward these packets, or manipulate group_fwd_mask
> >>> to allow it that way.
> >>
> >> These addresses must be forwarded only if the bridge is an S-VLAN
> >> bridge. When it is a C-VLAN bridge or a .1D bridge, they may not be
> >> forwarded. So, I don't think we can forward them always.
> >>
> >> Using group_fwd_mask is a bit complicated. If we use it to forward them,
> >> user can optionally turn off forwarding ability of those addresses...
> >> but we maybe need another information (named like group_fwd_mask_set)
> >> that indicates which bit is set by user. (We have to set group_fwd_mask
> >> automatically when we set vlan_proto to 88a8.)
> >> Is this way acceptable?
> > 
> > May be separate it into required mask and user mask.  Set required
> > mask when this is an S-VLAN bridge.
> Sounds like a good idea.
> I'll give it a try, thank you for your suggestion.
> Thanks,
> Toshiaki Makita

Looking again at the code.

1. If doing vlan then it should forward frames as defined in standard
   by default.

2. For compatiability, and for those users doing bump-on-wire, allow
   forwarding via group mask.

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