[IPV6]: Move nextheader offset to the IP6CB

Move nextheader offset to the IP6CB to make it possible to pass a
packet to ip6_input_finish multiple times and have it skip already
parsed headers. As a nice side effect this gets rid of the manual
hopopts skipping in ip6_input_finish.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index fbef782..da09ff2 100644
--- a/net/ipv6/xfrm6_tunnel.c
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -397,7 +397,7 @@
 
 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
 
-static int xfrm6_tunnel_rcv(struct sk_buff **pskb, unsigned int *nhoffp)
+static int xfrm6_tunnel_rcv(struct sk_buff **pskb)
 {
 	struct sk_buff *skb = *pskb;
 	struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
@@ -405,11 +405,11 @@
 	u32 spi;
 
 	/* device-like_ip6ip6_handler() */
-	if (handler && handler->handler(pskb, nhoffp) == 0)
+	if (handler && handler->handler(pskb) == 0)
 		return 0;
 
 	spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
-	return xfrm6_rcv_spi(pskb, nhoffp, spi);
+	return xfrm6_rcv_spi(pskb, spi);
 }
 
 static void xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,