gre: call skb_gro_checksum_simple_validate

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

1 files changed, 7 insertions, 36 deletions

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 6556263c8fa5..d1bd16937d93 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -119,28 +119,6 @@ out:
         return segs;
 }
 
-/* Compute the whole skb csum in s/w and store it, then verify GRO csum
- * starting from gro_offset.
- */
-static __sum16 gro_skb_checksum(struct sk_buff *skb)
-{
-        __sum16 sum;
-
-        skb->csum = skb_checksum(skb, 0, skb->len, 0);
-        NAPI_GRO_CB(skb)->csum = csum_sub(skb->csum,
-                csum_partial(skb->data, skb_gro_offset(skb), 0));
-        sum = csum_fold(NAPI_GRO_CB(skb)->csum);
-        if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) {
-                if (unlikely(!sum) && !skb->csum_complete_sw)
-                        netdev_rx_csum_fault(skb->dev);
-        } else {
-                skb->ip_summed = CHECKSUM_COMPLETE;
-                skb->csum_complete_sw = 1;
-        }
-
-        return sum;
-}
-
 static struct sk_buff **gre_gro_receive(struct sk_buff **head,
                                         struct sk_buff *skb)
 {
@@ -192,22 +170,15 @@ static struct sk_buff **gre_gro_receive(struct sk_buff **head,
                 if (unlikely(!greh))
                         goto out_unlock;
         }
-        if (greh->flags & GRE_CSUM) { /* Need to verify GRE csum first */
-                __sum16 csum = 0;
-
-                if (skb->ip_summed == CHECKSUM_COMPLETE)
-                        csum = csum_fold(NAPI_GRO_CB(skb)->csum);
-                /* Don't trust csum error calculated/reported by h/w */
-                if (skb->ip_summed == CHECKSUM_NONE || csum != 0)
-                        csum = gro_skb_checksum(skb);
-
-                /* GRE CSUM is the 1's complement of the 1's complement sum
-                 * of the GRE hdr plus payload so it should add up to 0xffff
-                 * (and 0 after csum_fold()) just like the IPv4 hdr csum.
-                 */
-                if (csum)
+
+        /* Don't bother verifying checksum if we're going to flush anyway. */
+        if (greh->flags & GRE_CSUM) {
+                if (!NAPI_GRO_CB(skb)->flush &&
+                    skb_gro_checksum_simple_validate(skb))
                         goto out_unlock;
+                NAPI_GRO_CB(skb)->encapsulation++;
         }
+
         flush = 0;
 
         for (p = *head; p; p = p->next) {