[IPSEC]: Set skb->data to payload in x->mode->output

This patch changes the calling convention so that on entry from
x->mode->output and before entry into x->type->output skb->data
will point to the payload instead of the IP header.

This is essentially a redistribution of skb_push/skb_pull calls
with the aim of minimising them on the common path of tunnel +
ESP.

It'll also let us use the same calling convention between IPv4
and IPv6 with the next patch.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c
index a73e710740c2..77888f596737 100644
--- a/net/ipv4/xfrm4_mode_beet.c
+++ b/net/ipv4/xfrm4_mode_beet.c
@@ -40,10 +40,11 @@ static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
         if (unlikely(optlen))
                 hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
 
-        skb_push(skb, x->props.header_len - IPV4_BEET_PHMAXLEN + hdrlen);
-        skb_reset_network_header(skb);
+        skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
+                                    hdrlen);
         top_iph = ip_hdr(skb);
         skb->transport_header += sizeof(*iph) - hdrlen;
+        __skb_pull(skb, sizeof(*iph) - hdrlen);
 
         memmove(top_iph, iph, sizeof(*iph));
         if (unlikely(optlen)) {