gre_offload: simplify GRE header length calculation in gre_gso_segment()

Simplify the GRE header length calculation in gre_gso_segment().
Switch to an approach that is simpler, faster, and more general. The
new approach will continue to be correct even if we add support for
the optional variable-length routing info that may be present in a GRE
header.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: H.K. Jerry Chu <hkchu@google.com>
Cc: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Neal Cardwell 2014-01-09 20:47:17 -05:00 committed by David S. Miller
parent 7eb8896df0
commit b884b1a46f
1 changed files with 6 additions and 10 deletions

View File

@ -26,7 +26,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
netdev_features_t enc_features;
int ghl = GRE_HEADER_SECTION;
int ghl;
struct gre_base_hdr *greh;
u16 mac_offset = skb->mac_header;
int mac_len = skb->mac_len;
@ -49,15 +49,11 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
greh = (struct gre_base_hdr *)skb_transport_header(skb);
if (greh->flags & GRE_KEY)
ghl += GRE_HEADER_SECTION;
if (greh->flags & GRE_SEQ)
ghl += GRE_HEADER_SECTION;
if (greh->flags & GRE_CSUM) {
ghl += GRE_HEADER_SECTION;
csum = true;
} else
csum = false;
ghl = skb_inner_network_header(skb) - skb_transport_header(skb);
if (unlikely(ghl < sizeof(*greh)))
goto out;
csum = !!(greh->flags & GRE_CSUM);
if (unlikely(!pskb_may_pull(skb, ghl)))
goto out;