Re: [Bridge] [RFC] bridge: allow passing link-local multicast

[Stephen Hemminger <shemminger@vyatta.com>]

On Thu, 18 Aug 2011 16:52:45 +0100
Nick Carter <ncarter100@gmail.com> wrote:

> On 18 August 2011 16:10, Stephen Hemminger <shemminger@vyatta.com> wrote:
> > On Thu, 18 Aug 2011 16:06:19 +0100
> > Nick Carter <ncarter100@gmail.com> wrote:
> >
> >> Why can't we use the 802.1D specified STP group address to identify ?
> >> The existing code uses that address.
> >> I know you said on another thread that there are people using other addresses.
> >> Who are these people ?
> >> Are they following any standard ?
> >> What address / address range are they using ?
> >
> > The group address can be reprogrammed, and it is settable on other
> > routing equipment. People do it to create spanning tree domains.
> >
> But before the new
> +               if (!is_stp_bpdu(skb) && br_forward_link_local)
> check, we have already checked
> 	if (unlikely(is_link_local(dest))) {
> So the frame must have a link local destination.  If the reprogrammed
> group address is outside of the link local range then the new code in
> this patch will never be hit.  If the reprogrammed group address is in
> the link local range then i'd suggest my previous group_fwd_mask patch
> is cleaner and more flexible.

The problem is that the group_fwd_mask is specific to the address
not the protocol.