[SK_BUFF]: Introduce skb_transport_offset()

For the quite common 'skb->h.raw - skb->data' sequence.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 6 deletions

diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 7aff380e74ef..35905867ded1 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -42,21 +42,18 @@
 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 {
         int err;
-        int hdr_len;
         struct ipv6hdr *top_iph;
         struct ipv6_esp_hdr *esph;
         struct crypto_blkcipher *tfm;
         struct blkcipher_desc desc;
-        struct esp_data *esp;
         struct sk_buff *trailer;
         int blksize;
         int clen;
         int alen;
         int nfrags;
-
-        esp = x->data;
-        hdr_len = skb->h.raw - skb->data +
-                  sizeof(*esph) + esp->conf.ivlen;
+        struct esp_data *esp = x->data;
+        int hdr_len = (skb_transport_offset(skb) +
+                       sizeof(*esph) + esp->conf.ivlen);
 
         /* Strip IP+ESP header. */
         __skb_pull(skb, hdr_len);