[NETFILTER] bridge: simplify nf_bridge_pad

Do some simple optimization on the nf_bridge_pad() function
and don't use magic constants. Eliminate a double call and
the #ifdef'd code for CONFIG_BRIDGE_NETFILTER.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter_bridge.h

@@ -5,9 +5,8 @@
  */
 
 #include <linux/netfilter.h>
-#if defined(__KERNEL__) && defined(CONFIG_BRIDGE_NETFILTER)
 #include <linux/if_ether.h>
-#endif
+#include <linux/if_vlan.h>
 
 /* Bridge Hooks */
 /* After promisc drops, checksum checks. */
@@ -57,16 +56,10 @@ static inline int nf_bridge_maybe_copy_header(struct sk_buff *skb)
 
 /* This is called by the IP fragmenting code and it ensures there is
  * enough room for the encapsulating header (if there is one). */
-static inline
-int nf_bridge_pad(struct sk_buff *skb)
+static inline int nf_bridge_pad(const struct sk_buff *skb)
 {
-	if (skb->protocol == __constant_htons(ETH_P_IP))
-		return 0;
-	if (skb->nf_bridge) {
-		if (skb->protocol == __constant_htons(ETH_P_8021Q))
-			return 4;
-	}
-	return 0;
+ 	return (skb->nf_bridge && skb->protocol == htons(ETH_P_8021Q))
+		? VLAN_HLEN : 0;
 }
 
 struct bridge_skb_cb {
@@ -78,6 +71,7 @@ struct bridge_skb_cb {
 extern int brnf_deferred_hooks;
 #else
 #define nf_bridge_maybe_copy_header(skb)	(0)
+#define nf_bridge_pad(skb)			(0)
 #endif /* CONFIG_BRIDGE_NETFILTER */
 
 #endif /* __KERNEL__ */

net/ipv4/ip_output.c

@@ -426,7 +426,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
 	int ptr;
 	struct net_device *dev;
 	struct sk_buff *skb2;
-	unsigned int mtu, hlen, left, len, ll_rs;
+	unsigned int mtu, hlen, left, len, ll_rs, pad;
 	int offset;
 	__be16 not_last_frag;
 	struct rtable *rt = (struct rtable*)skb->dst;
@@ -556,14 +556,13 @@ slow_path:
 	left = skb->len - hlen;		/* Space per frame */
 	ptr = raw + hlen;		/* Where to start from */
 
-#ifdef CONFIG_BRIDGE_NETFILTER
 	/* for bridged IP traffic encapsulated inside f.e. a vlan header,
-	 * we need to make room for the encapsulating header */
-	ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, nf_bridge_pad(skb));
-	mtu -= nf_bridge_pad(skb);
-#else
-	ll_rs = LL_RESERVED_SPACE(rt->u.dst.dev);
-#endif
+	 * we need to make room for the encapsulating header
+	 */
+	pad = nf_bridge_pad(skb);
+	ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, pad);
+	mtu -= pad;
+
 	/*
 	 *	Fragment the datagram.
 	 */