[IPSEC]: Use IPv6 calling convention as the convention for x->mode->output

The IPv6 calling convention for x->mode->output is more general and could
help an eventual protocol-generic x->type->output implementation.  This
patch adopts it for IPv4 as well and modifies the IPv4 type output functions
accordingly.

It also rewrites the IPv6 mac/transport header calculation to be based off
the network header where practical.

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

1 files changed, 3 insertions, 4 deletions

diff --git a/net/ipv4/xfrm4_mode_transport.c b/net/ipv4/xfrm4_mode_transport.c
index 10499d2ec65e..fd840c7d75ea 100644
--- a/net/ipv4/xfrm4_mode_transport.c
+++ b/net/ipv4/xfrm4_mode_transport.c
@@ -17,17 +17,16 @@
  *
  * The IP header will be moved forward to make space for the encapsulation
  * header.
- *
- * On exit, skb->h will be set to the start of the payload to be processed
- * by x->type->output and skb->nh will be set to the top IP header.
  */
 static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
 {
         struct iphdr *iph = ip_hdr(skb);
         int ihl = iph->ihl * 4;
 
-        skb->transport_header = skb->network_header + ihl;
         skb_set_network_header(skb, -x->props.header_len);
+        skb->mac_header = skb->network_header +
+                          offsetof(struct iphdr, protocol);
+        skb->transport_header = skb->network_header + ihl;
         __skb_pull(skb, ihl);
         memmove(skb_network_header(skb), iph, ihl);
         return 0;