[PATCH net 2/5] i40e: Implement ndo_gso_check()

[Joe Stringer <joestringer@nicira.com>]

ndo_gso_check() was recently introduced to allow NICs to report the
offloading support that they have on a per-skb basis. Add an
implementation for this driver which checks for tunnel headers over UDP
of up to 64 octets in length.

Implementation shamelessly stolen from Tom Herbert:
http://thread.gmane.org/gmane.linux.network/332428/focus=333111

Signed-off-by: Joe Stringer <joestringer@nicira.com>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index c3a7f4a..21829b5 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -7444,9 +7444,20 @@ static int i40e_ndo_fdb_dump(struct sk_buff *skb,
 
 	return idx;
 }
-
 #endif /* USE_DEFAULT_FDB_DEL_DUMP */
 #endif /* HAVE_FDB_OPS */
+
+static bool i40e_gso_check(struct sk_buff *skb, struct net_device *dev)
+{
+	if ((skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) &&
+	    (skb->inner_protocol_type != ENCAP_TYPE_ETHER ||
+	     skb->inner_protocol != htons(ETH_P_TEB) ||
+	     skb_inner_mac_header(skb) - skb_transport_header(skb) > 64))
+		return false;
+
+	return true;
+}
+
 static const struct net_device_ops i40e_netdev_ops = {
 	.ndo_open		= i40e_open,
 	.ndo_stop		= i40e_close,
@@ -7487,6 +7498,7 @@ static const struct net_device_ops i40e_netdev_ops = {
 	.ndo_fdb_dump		= i40e_ndo_fdb_dump,
 #endif
 #endif
+	.ndo_gso_check		= i40e_gso_check,
 };
 
 /**
-- 
1.7.10.4