[PATCH v5 net-next 6/8] net: gre: Implement LCO for GRE over IPv4

[Edward Cree]

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 net/ipv4/ip_gre.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 7c51c4e..9b31532 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -440,6 +440,17 @@ drop:
        return 0;
 }
 
+static __sum16 gre_checksum(struct sk_buff *skb)
+{
+       __wsum csum;
+
+       if (skb->ip_summed == CHECKSUM_PARTIAL)
+               csum = lco_csum(skb);
+       else
+               csum = skb_checksum(skb, 0, skb->len, 0);
+       return csum_fold(csum);
+}
+
 static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags,
                         __be16 proto, __be32 key, __be32 seq)
 {
@@ -467,8 +478,7 @@ static void build_header(struct sk_buff *skb, int hdr_len, 
__be16 flags,
                    !(skb_shinfo(skb)->gso_type &
                      (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
                        *ptr = 0;
-                       *(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
-                                                                skb->len, 0));
+                       *(__sum16 *)ptr = gre_checksum(skb);
                }
        }
 }
@@ -493,7 +503,7 @@ static void __gre_xmit(struct sk_buff *skb, struct 
net_device *dev,
 static struct sk_buff *gre_handle_offloads(struct sk_buff *skb,
                                           bool csum)
 {
-       return iptunnel_handle_offloads(skb, csum,
+       return iptunnel_handle_offloads(skb, false,
                                        csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
 }