[BRIDGE]: Fix LL_RESERVED_SPACE usage in netfilter code.

include/linux/netdevice.h

@@ -215,6 +215,8 @@ struct hh_cache
  */
 #define LL_RESERVED_SPACE(dev) \
 	(((dev)->hard_header_len&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
+#define LL_RESERVED_SPACE_EXTRA(dev,extra) \
+	((((dev)->hard_header_len+extra)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
 
 /* These flag bits are private to the generic network queueing
  * layer, they may not be explicitly referenced by any other

net/ipv4/ip_output.c

@@ -567,7 +567,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
 #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(rt->u.dst.dev + nf_bridge_pad(skb));
+	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);