On 18 August 2011 16:10, Stephen Hemminger [off-list ref] wrote:

On Thu, 18 Aug 2011 16:06:19 +0100
Nick Carter [off-list ref] wrote:

quoted

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.

Nick