[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, 11 deletions

diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
index 01bd7d11ea1b..e79c6bdf71c1 100644
--- a/net/ipv6/xfrm6_mode_tunnel.c
+++ b/net/ipv6/xfrm6_mode_tunnel.c
@@ -36,13 +36,6 @@ static inline void ip6ip_ecn_decapsulate(struct sk_buff *skb)
  * The top IP header will be constructed per RFC 2401.  The following fields
  * in it shall be filled in by x->type->output:
  *      payload_len
- *
- * On exit, skb->h will be set to the start of the encapsulation header to be
- * filled in by x->type->output and the mac header will be set to the
- * nextheader field of the extension header directly preceding the
- * encapsulation header, or in its absence, that of the top IP header.
- * The value of the network header will always point to the top IP header
- * while skb->data will point to the payload.
  */
 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 {
@@ -53,11 +46,10 @@ static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 
         iph = ipv6_hdr(skb);
 
-        skb_set_mac_header(skb, offsetof(struct ipv6hdr, nexthdr) -
-                                x->props.header_len);
         skb_set_network_header(skb, -x->props.header_len);
-        skb_set_transport_header(skb, sizeof(struct ipv6hdr) -
-                                      x->props.header_len);
+        skb->mac_header = skb->network_header +
+                          offsetof(struct ipv6hdr, nexthdr);
+        skb->transport_header = skb->network_header + sizeof(*iph);
         top_iph = ipv6_hdr(skb);
 
         top_iph->version = 6;