[ovs-dev] [PATCH/RFC net-next] openvswitch: allow output of MPLS packets on tunnel vports

[Pravin Shelar]

On Mon, Jun 15, 2015 at 5:39 PM, Simon Horman
<simon.horman at netronome.com> wrote:
> Currently output of MPLS packets on tunnel vports is not allowed by the
> datapath and, moreover, flows that match on MPLS packets and output to
> tunnel vports are rejected by the datapath. The flows are rejected
> regardless of if they also output to non-tunnel vports which is allowed for
> MPLS packets and the following is logged by the kernel.
>
> openvswitch: netlink: Flow actions may not be safe on all matching packets.
>
> This patch addresses the above by allowing output of MPLS packets to tunnel
> vports.
>
> My recollection of adding MPLS support to the datapath was that a rather
> conservative approach was taken in order to minimise the chance of fallout.
> This patch proposes relaxing one restriction which was introduced at that
> time.
>
> My limited testing has not isolated any side effects of this change.
>
> Signed-off-by: Simon Horman <simon.horman at netronome.com>
> ---
>  net/openvswitch/flow_netlink.c | 3 ---
>  1 file changed, 3 deletions(-)
>
> diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
> index 624e41c4267f..a5d3c0ae8ac8 100644
> --- a/net/openvswitch/flow_netlink.c
> +++ b/net/openvswitch/flow_netlink.c
> @@ -1847,9 +1847,6 @@ static int validate_set(const struct nlattr *a,
>                 break;
>
>         case OVS_KEY_ATTR_TUNNEL:
> -               if (eth_p_mpls(eth_type))
> -                       return -EINVAL;
> -
One of the problem is with setting skb->inner_protocol. MPLS and
tunnel both needs to set inner protocol field. So outer encapsulation
would just overwrite earlier inner protocol field on packet transit
path.