gre: Call gso_make_checksum

Call gso_make_checksum. This should have the benefit of using a
checksum that may have been previously computed for the packet.

This also adds NETIF_F_GSO_GRE_CSUM to differentiate devices that
offload GRE GSO with and without the GRE checksum offloaed.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/include/net/gre.h b/include/net/gre.h
index 70046a0b0b89..b53182018743 100644
--- a/include/net/gre.h
+++ b/include/net/gre.h
@@ -37,9 +37,10 @@ void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
                       int hdr_len);
 
 static inline struct sk_buff *gre_handle_offloads(struct sk_buff *skb,
-                                                  bool gre_csum)
+                                                  bool csum)
 {
-        return iptunnel_handle_offloads(skb, gre_csum, SKB_GSO_GRE);
+        return iptunnel_handle_offloads(skb, csum,
+                                        csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
 }