[ovs-dev] [PATCH] tc: handle packet mark of zero

Simon Horman simon.horman at netronome.com
Mon Jan 13 10:03:17 UTC 2020


Hi,

On Mon, Jan 13, 2020 at 05:28:04PM +0800, Tonghao Zhang wrote:
> On Fri, Jan 10, 2020 at 7:06 PM Simon Horman <simon.horman at netronome.com> wrote:
> >
> > From: John Hurley <john.hurley at netronome.com>
> >
> > Openstack may set an skb mark of 0 in tunnel rules. This is considered to
> > be an unused/unset value. However, it prevents the rule from being
> > offloaded.
> >
> > Check if the key value of the skb mark is 0 when it is in use (mask is
> > set to all ones). If it is then ignore the field and continue with TC offload.
> >
> > Signed-off-by: John Hurley <john.hurley at netronome.com>
> > [simon; check for exact-match rather than any match]
> > Signed-off-by: Simon Horman <simon.horman at netronome.com>
> > ---
> >  lib/netdev-offload-tc.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/lib/netdev-offload-tc.c b/lib/netdev-offload-tc.c
> > index 7453078d535f..daff8a379e97 100644
> > --- a/lib/netdev-offload-tc.c
> > +++ b/lib/netdev-offload-tc.c
> > @@ -1619,6 +1619,11 @@ netdev_tc_flow_put(struct netdev *netdev, struct match *match,
> >          mask->ct_label = OVS_U128_ZERO;
> >      }
> >
> > +    /* ignore exact match on skb_mark of 0. */
> > +    if (mask->pkt_mark == UINT32_MAX && !key->pkt_mark) {
> > +        mask->pkt_mark = 0;
> > +    }
> Why not: if (!(mask->pkt_mark & key->pkt_mark))

Its not clear to me that only returns true in the case
where there is an exact match on pkt_mark 0. Which is the case
that is considered to be an unused/unset value from a HW offload
perspective.

> 
> >      err = test_key_and_mask(match);
> >      if (err) {
> >          return err;
> > --
> > 2.20.1
> >
> > _______________________________________________
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> > dev at openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev


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