[NETFILTER]: bridge netfilter: add deferred output hooks to feature-removal-schedule

Add bridge netfilter deferred output hooks to feature-removal-schedule
and disable them by default. Until their removal they will be
activated by the physdev match when needed.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/feature-removal-schedule.txt

@@ -258,3 +258,19 @@ Why:	These drivers never compiled since they were added to the kernel
 Who:	Jean Delvare <khali@linux-fr.org>
 
 ---------------------------
+
+What:	Bridge netfilter deferred IPv4/IPv6 output hook calling
+When:	January 2007
+Why:	The deferred output hooks are a layering violation causing unusual
+	and broken behaviour on bridge devices. Examples of things they
+	break include QoS classifation using the MARK or CLASSIFY targets,
+	the IPsec policy match and connection tracking with VLANs on a
+	bridge. Their only use is to enable bridge output port filtering
+	within iptables with the physdev match, which can also be done by
+	combining iptables and ebtables using netfilter marks. Until it
+	will get removed the hook deferral is disabled by default and is
+	only enabled when needed.
+
+Who:	Patrick McHardy <kaber@trash.net>
+
+---------------------------

include/linux/netfilter_bridge.h

@@ -79,6 +79,8 @@ struct bridge_skb_cb {
 		__u32 ipv4;
 	} daddr;
 };
+
+extern int brnf_deferred_hooks;
 #endif /* CONFIG_BRIDGE_NETFILTER */
 
 #endif /* __KERNEL__ */

net/bridge/br_netfilter.c

@@ -61,6 +61,9 @@ static int brnf_filter_vlan_tagged = 1;
 #define brnf_filter_vlan_tagged 1
 #endif
 
+int brnf_deferred_hooks;
+EXPORT_SYMBOL_GPL(brnf_deferred_hooks);
+
 static __be16 inline vlan_proto(const struct sk_buff *skb)
 {
 	return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
@@ -890,6 +893,8 @@ static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb,
 				return NF_ACCEPT;
 			else if (ip->version == 6 && !brnf_call_ip6tables)
 				return NF_ACCEPT;
+			else if (!brnf_deferred_hooks)
+				return NF_ACCEPT;
 #endif
 			if (hook == NF_IP_POST_ROUTING)
 				return NF_ACCEPT;

net/netfilter/xt_physdev.c

@@ -113,6 +113,21 @@ checkentry(const char *tablename,
 	if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
 	    info->bitmask & ~XT_PHYSDEV_OP_MASK)
 		return 0;
+	if (brnf_deferred_hooks == 0 &&
+	    info->bitmask & XT_PHYSDEV_OP_OUT &&
+	    (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
+	     info->invert & XT_PHYSDEV_OP_BRIDGED) &&
+	    hook_mask & ((1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_FORWARD) |
+	                 (1 << NF_IP_POST_ROUTING))) {
+		printk(KERN_WARNING "physdev match: using --physdev-out in the "
+		       "OUTPUT, FORWARD and POSTROUTING chains for non-bridged "
+		       "traffic is deprecated and breaks other things, it will "
+		       "be removed in January 2007. See Documentation/"
+		       "feature-removal-schedule.txt for details. This doesn't "
+		       "affect you in case you're using it for purely bridged "
+		       "traffic.\n");
+		brnf_deferred_hooks = 1;
+	}
 	return 1;
 }