[ovs-dev] [PATCH v2] tc: handle packet mark of zero

[Aaron Conole]

Simon Horman <simon.horman at netronome.com> writes:

> 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.
>
> Only the exact-match case is covered by this patch as it addresses the
> Openstack use-case and seems most robust against feature evolution: f.e. in
> future there may exist hardware offload scenarios where an operation, such
> as a BPF offload, sets the SKB mark before proceeding tho the in-HW OVS.
> datapath.
>
> Signed-off-by: John Hurley <john.hurley at netronome.com>
> Co-Authored: Simon Horman <simon.horman at netronome.com>
> Signed-off-by: Simon Horman <simon.horman at netronome.com>
>
> ---

With the change to the Co-Authored tag:

Acked-by: Aaron Conole <aconole at redhat.com>

> v0 [John Hurley]
>
> v1 [Simon Horman]
> * Check for exact rather than masked match on skb 0
>
> v2 [Simon Horman]
> * Add co-authored tag
>   Add explanation of check against exact-match to changelog
> ---
>  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 4988dadc3f50..5781d163e276 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;
> +    }
> +
>      err = test_key_and_mask(match);
>      if (err) {
>          return err;