> If an MPLS packet requires segmentation then use mpls_features
> to determine if the software implementation should be used.
>
> As no driver advertises MPLS GSO segmentation this will always be
> the case.
>
> I had not noticed that this was necessary before as software MPLS GSO
> segmentation was already being used in my test environment. I believe that
> the reason for that is the skbs in question always had fragments and the
> driver I used does not advertise NETIF_F_FRAGLIST (which seems to be the
> case for most drivers). Thus software segmentation was activated by
> skb_gso_ok().
>
> Thanks to Jesse Gross for prompting me to investigate this.
>
> Acked-by: Jesse Gross <je...@nicira.com>
> Signed-off-by: Simon Horman <ho...@verge.net.au>
>
> ---
> v3
> * As requested by David Miller
> - Do not mark net_mpls_features as inline
> - Correct alignment of parameters
>
> v2
> * Added Ack from Jesse Gross
> * Removed duplicate 'Thus' from changelog
> ---
> net/core/dev.c | 38 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 38 insertions(+)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 0355ca5..1aa7004 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2540,6 +2540,42 @@ netdev_features_t netif_skb_features(struct sk_buff
> *skb)
> }
> EXPORT_SYMBOL(netif_skb_features);
>
> +/* If MPLS offload request, verify we are testing hardware MPLS features
> + * instead of standard features for the netdev.
> + */
> +#ifdef CONFIG_NET_MPLS_GSO
> +static netdev_features_t net_mpls_features(struct sk_buff *skb,
> + struct net_device *dev,
> + netdev_features_t features)
> +{
> + /* There is no support for MPLS LRO. So the only way that
> + * an MPLS skb could require GSO segmentation is if it
> + * was received as a non-MPLS skb and then became an MPLS skb.
> + * This may be effected by Open vSwitch in which case the
> + * mac_len will non-zero and not equal to skb_network_offset
> + * as the former indicates the end of L2 the latter indicates
s/L2/& and/
> + * the beginning of L3 and there is a gap between them occupied
> + * by the MPLS label stack.
> + *
> + * Thus it is possible to avoid traversing any VLAN tags that are
> + * present to determine if the ethtype is MPLS. Instead the
> + * inequality of mac_llen and skb_network_offset are used to
s/mac_llen/mac_len/
Acked-by: YAMAMOTO Takashi <yamam...@valinux.co.jp>
YAMAMOTO Takashi
> + * determine if a packet is MPLS for the purpose of determining
> + * offload features.
> + */
> + if (skb->mac_len && skb->mac_len != skb_network_offset(skb))
> + features &= dev->mpls_features;
> + return features;
> +}
> +#else
> +static netdev_features_t net_mpls_features(struct sk_buff *skb,
> + struct net_device *dev,
> + netdev_features_t features)
> +{
> + return features;
> +}
> +#endif
> +
> int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
> struct netdev_queue *txq)
> {
> @@ -2576,6 +2612,8 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct
> net_device *dev,
> if (skb->encapsulation)
> features &= dev->hw_enc_features;
>
> + features = net_mpls_features(skb, dev, features);
> +
> if (netif_needs_gso(skb, features)) {
> if (unlikely(dev_gso_segment(skb, features)))
> goto out_kfree_skb;
> --
> 1.8.5.2
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> http://openvswitch.org/mailman/listinfo/dev
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