On Thu, Aug 18, 2011 at 09:39:41AM -0700, Stephen Hemminger wrote:

On Thu, 18 Aug 2011 16:52:45 +0100
Nick Carter [off-list ref] wrote:

quoted

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

quoted

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.

I just checked my hardware switches. Neither my Cisco devices nor my HP
ProCurves can reprogram the spanning tree address.

Can you provide an example? Even Linux can't do this, can it?

quoted

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.

Until corrected, I would consider either match a valid option, and I
would say Nick's patch is much cleaner than yours.

Also, you're arguing against yourself, saying that matching the address
is a problem, but the code you're proposing does exactly that - it first
matches the address (is_link_local()), then the protocol. (wtf?)


-David