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authorVlad Yasevich <vyasevich@gmail.com>2017-05-23 13:38:41 -0400
committerDavid S. Miller <davem@davemloft.net>2017-05-24 16:27:14 -0400
commit35d2f80b07bbe03fb358afb0bdeff7437a7d67ff (patch)
treebc2dc13dc4416dae8b0a57460f5d13aa65e6ffec /include/linux/if_vlan.h
parentf2899788353c13891412b273fdff5f02d49aa40f (diff)
vlan: Fix tcp checksum offloads in Q-in-Q vlans
It appears that TCP checksum offloading has been broken for Q-in-Q vlans. The behavior was execerbated by the series commit afb0bc972b52 ("Merge branch 'stacked_vlan_tso'") that that enabled accleleration features on stacked vlans. However, event without that series, it is possible to trigger this issue. It just requires a lot more specialized configuration. The root cause is the interaction between how netdev_intersect_features() works, the features actually set on the vlan devices and HW having the ability to run checksum with longer headers. The issue starts when netdev_interesect_features() replaces NETIF_F_HW_CSUM with a combination of NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM, if the HW advertises IP|IPV6 specific checksums. This happens for tagged and multi-tagged packets. However, HW that enables IP|IPV6 checksum offloading doesn't gurantee that packets with arbitrarily long headers can be checksummed. This patch disables IP|IPV6 checksums on the packet for multi-tagged packets. CC: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> CC: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com> Acked-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/if_vlan.h')
-rw-r--r--include/linux/if_vlan.h18
1 files changed, 10 insertions, 8 deletions
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index 8d5fcd6284ce..283dc2f5364d 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -614,14 +614,16 @@ static inline bool skb_vlan_tagged_multi(const struct sk_buff *skb)
static inline netdev_features_t vlan_features_check(const struct sk_buff *skb,
netdev_features_t features)
{
- if (skb_vlan_tagged_multi(skb))
- features = netdev_intersect_features(features,
- NETIF_F_SG |
- NETIF_F_HIGHDMA |
- NETIF_F_FRAGLIST |
- NETIF_F_HW_CSUM |
- NETIF_F_HW_VLAN_CTAG_TX |
- NETIF_F_HW_VLAN_STAG_TX);
+ if (skb_vlan_tagged_multi(skb)) {
+ /* In the case of multi-tagged packets, use a direct mask
+ * instead of using netdev_interesect_features(), to make
+ * sure that only devices supporting NETIF_F_HW_CSUM will
+ * have checksum offloading support.
+ */
+ features &= NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_HW_CSUM |
+ NETIF_F_FRAGLIST | NETIF_F_HW_VLAN_CTAG_TX |
+ NETIF_F_HW_VLAN_STAG_TX;
+ }
return features;
}