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MPLS: Use mpls_features to activate software MPLS GSO segmentation

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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().

This introduces the overhead of an extra call to skb_network_protocol()
in the case where where CONFIG_NET_MPLS_GSO is set and
skb->ip_summed == CHECKSUM_NONE.

Thanks to Jesse Gross for prompting me to investigate this.

Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Simon Horman 2014-06-04 08:53:17 +09:00 • committed by David S. Miller
commit 3b392ddba2
1 changed files with 27 additions and 1 deletions
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28
net/core/dev.c
View file

@ -2513,13 +2513,39 @@ static int dev_gso_segment(struct sk_buff *skb, netdev_features_t features)
return 0;
}
/* 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,
netdev_features_t features,
__be16 type)
{
if (type == htons(ETH_P_MPLS_UC) || type == htons(ETH_P_MPLS_MC))
features &= skb->dev->mpls_features;
return features;
}
#else
static netdev_features_t net_mpls_features(struct sk_buff *skb,
netdev_features_t features,
__be16 type)
{
return features;
}
#endif
static netdev_features_t harmonize_features(struct sk_buff *skb,
netdev_features_t features)
{
int tmp;
__be16 type;
type = skb_network_protocol(skb, &tmp);
features = net_mpls_features(skb, features, type);
if (skb->ip_summed != CHECKSUM_NONE &&
!can_checksum_protocol(features, skb_network_protocol(skb, &tmp))) {
!can_checksum_protocol(features, type)) {
features &= ~NETIF_F_ALL_CSUM;
} else if (illegal_highdma(skb->dev, skb)) {
features &= ~NETIF_F_SG;