netfilter: bridge: reduce nf_bridge_info to 32 bytes again

We can use union for most of the temporary cruft (original ipv4/ipv6
address, source mac, physoutdev) since they're used during different
stages of br netfilter traversal.

Also get rid of the last two ->mask users.

Shrinks struct from 48 to 32 on 64bit arch.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d6cdd6e..ac732e6 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -173,17 +173,24 @@
 		BRNF_PROTO_8021Q,
 		BRNF_PROTO_PPPOE
 	} orig_proto:8;
-	bool			pkt_otherhost;
+	u8			pkt_otherhost:1;
+	u8			in_prerouting:1;
+	u8			bridged_dnat:1;
 	__u16			frag_max_size;
-	unsigned int		mask;
 	struct net_device	*physindev;
 	union {
-		struct net_device *physoutdev;
-		char neigh_header[8];
-	};
-	union {
+		/* prerouting: detect dnat in orig/reply direction */
 		__be32          ipv4_daddr;
 		struct in6_addr ipv6_daddr;
+
+		/* after prerouting + nat detected: store original source
+		 * mac since neigh resolution overwrites it, only used while
+		 * skb is out in neigh layer.
+		 */
+		char neigh_header[8];
+
+		/* always valid & non-NULL from FORWARD on, for physdev match */
+		struct net_device *physoutdev;
 	};
 };
 #endif