netfilter: bridge: start splitting mask into public/private chunks

->mask is a bit info field that mixes various use cases.

In particular, we have flags that are mutually exlusive, and flags that
are only used within br_netfilter while others need to be exposed to
other parts of the kernel.

Remove BRNF_8021Q/PPPoE flags.  They're mutually exclusive and only
needed within br_netfilter context.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 301f12b..ab1e988 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -262,10 +262,16 @@
 
 static void nf_bridge_update_protocol(struct sk_buff *skb)
 {
-	if (skb->nf_bridge->mask & BRNF_8021Q)
+	switch (skb->nf_bridge->orig_proto) {
+	case BRNF_PROTO_8021Q:
 		skb->protocol = htons(ETH_P_8021Q);
-	else if (skb->nf_bridge->mask & BRNF_PPPoE)
+		break;
+	case BRNF_PROTO_PPPOE:
 		skb->protocol = htons(ETH_P_PPP_SES);
+		break;
+	case BRNF_PROTO_UNCHANGED:
+		break;
+	}
 }
 
 /* PF_BRIDGE/PRE_ROUTING *********************************************/
@@ -503,10 +509,11 @@
 	nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
 	nf_bridge->physindev = skb->dev;
 	skb->dev = brnf_get_logical_dev(skb, skb->dev);
+
 	if (skb->protocol == htons(ETH_P_8021Q))
-		nf_bridge->mask |= BRNF_8021Q;
+		nf_bridge->orig_proto = BRNF_PROTO_8021Q;
 	else if (skb->protocol == htons(ETH_P_PPP_SES))
-		nf_bridge->mask |= BRNF_PPPoE;
+		nf_bridge->orig_proto = BRNF_PROTO_PPPOE;
 
 	/* Must drop socket now because of tproxy. */
 	skb_orphan(skb);