vlan: Enable software emulation for vlan accleration.

Currently users of hardware vlan accleration need to know whether
the device supports it before generating packets.  However, vlan
acceleration will soon be available in a more flexible manner so
knowing ahead of time becomes much more difficult.  This adds
a software fallback path for vlan packets on devices without the
necessary offloading support, similar to other types of hardware
accleration.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 3 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 880d56565828..2861565a27d9 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2248,9 +2248,17 @@ static inline int skb_gso_ok(struct sk_buff *skb, int features)
 
 static inline int netif_needs_gso(struct net_device *dev, struct sk_buff *skb)
 {
-        return skb_is_gso(skb) &&
-               (!skb_gso_ok(skb, dev->features) ||
-                unlikely(skb->ip_summed != CHECKSUM_PARTIAL));
+        if (skb_is_gso(skb)) {
+                int features = dev->features;
+
+                if (skb->protocol == htons(ETH_P_8021Q) || skb->vlan_tci)
+                        features &= dev->vlan_features;
+
+                return (!skb_gso_ok(skb, features) ||
+                        unlikely(skb->ip_summed != CHECKSUM_PARTIAL));
+        }
+
+        return 0;
 }
 
 static inline void netif_set_gso_max_size(struct net_device *dev,