On Mon, 2009-05-04 at 11:01 -0700, Joe Eykholt wrote:
> Robert Love wrote:
> > On Fri, 2009-05-01 at 11:27 -0700, Joe Eykholt wrote:
> >> Love, Robert W wrote:
> >
> > <snip>
> >
> >>>> find_skbedit_filter()
> >>>> {
> >>>> ifname=$1
> >>>> + ethertype=$2
> >>>> + filter_id=$3
> >>>>
> >>>> found=`tc filter show dev $ifname | awk '
> >>>> BEGIN {
> >>>> @@ -120,11 +118,11 @@ find_skbedit_filter()
> >>>> x3 = 0
> >>>> queue = 8
> >>>> }
> >>>> - /^filter.*parent.*protocol '$FCOE_ETHERTYPE'.* handle
> >>>> '$FILTER_ID'/
> >>>> { + /^filter.*parent.*protocol \['$ethertype'\].* handle
> >>>> '$filter_id'/ { if (x1 == 0 && x2 == 0 && x3 == 0)
> >>>> x1 = 1
> >>>> }
> >>>> - /cmp.*u16 at 12 layer 1 mask 0xffff eq '$FCOE_ETHERTYPE'.*\)/ {
> >>>> + /cmp.*u16 at 12 layer 1 mask 0xffff eq '$ethertype'.*\)/ {
> >> Now since we're matching on the
> >> protocol, I don't think we need to do the equivalent compare of the
> >> "u16 at 12", which is also the ethertype. That was only necessary before
> >> tc could take arbitrary ethertypes. Of course, this doesn't do any harm
> >> as far as I can tell.
> >>
> > Are you suggesting that we can remove the cmp or that the cmp should be
> > written more elegantly? Can you show me the preferred syntax? I've
> > played around, but I can't get it right.
>
> It seems to me the cmp can be removed, since the filter is already specifying
> the ethertype. tc matches the protocol and then does the cmp
> which matches again. It used to be that we specified the protocol as 802.3
> and then the cmp with the ethertype was needed. But now, it isn't.
>
My understanding is that the protocol field is only used to identify
which header to look into, before running the compare operation, so even
if we specify FCoE we're just getting to the L2 header and we'd still
need to have compare criteria to find the FCoE ethertype. This would
also require tc to be aware of the FCoE ethertype, which I don't think
it is.
Is there a specific kernel patch(s) that has changed this behavior that
you can point me to? If it has changed, I'd like to know, but I'm not
aware that it has. Or, if you can you tell me what the correct syntax
would be to accomplish what you're asking for it would help a lot.
Right now I'm not convinced that we can simplify this.
_______________________________________________
devel mailing list
[email protected]
http://www.open-fcoe.org/mailman/listinfo/devel
