[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, 7 insertions, 10 deletions

diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c
index 77888f59673..7226c6486c0 100644
--- a/net/ipv4/xfrm4_mode_beet.c
+++ b/net/ipv4/xfrm4_mode_beet.c
@@ -23,17 +23,14 @@
  * The following fields in it shall be filled in by x->type->output:
  *      tot_len
  *      check
- *
- * 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_beet_output(struct xfrm_state *x, struct sk_buff *skb)
 {
+        struct ip_beet_phdr *ph;
         struct iphdr *iph, *top_iph;
         int hdrlen, optlen;
 
         iph = ip_hdr(skb);
-        skb->transport_header = skb->network_header;
 
         hdrlen = 0;
         optlen = iph->ihl * 4 - sizeof(*iph);
@@ -42,17 +39,17 @@ static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *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);
+        skb->mac_header = skb->network_header +
+                          offsetof(struct iphdr, protocol);
+        skb->transport_header = skb->network_header + sizeof(*iph);
+
+        ph = (struct ip_beet_phdr *)__skb_pull(skb, sizeof(*iph) - hdrlen);
 
+        top_iph = ip_hdr(skb);
         memmove(top_iph, iph, sizeof(*iph));
         if (unlikely(optlen)) {
-                struct ip_beet_phdr *ph;
-
                 BUG_ON(optlen < 0);
 
-                ph = (struct ip_beet_phdr *)skb_transport_header(skb);
                 ph->padlen = 4 - (optlen & 4);
                 ph->hdrlen = optlen / 8;
                 ph->nexthdr = top_iph->protocol;