[NETFILTER]: Core changes required by upcoming nfnetlink_queue code

- split netfiler verdict in 16bit verdict and 16bit queue number
- add 'queuenum' argument to nf_queue_outfn_t and its users ip[6]_queue
- move NFNL_SUBSYS_ definitions from enum to #define
- introduce autoloading for nfnetlink subsystem modules
- add MODULE_ALIAS_NFNL_SUBSYS macro
- add nf_unregister_queue_handlers() to register all handlers for a given
  nf_queue_outfn_t
- add more verbose DEBUGP macro definition to nfnetlink.c
- make nfnetlink_subsys_register fail if subsys already exists
- add some more comments and debug statements to nfnetlink.c

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter.h

@@ -21,6 +21,16 @@
 #define NF_STOP 5
 #define NF_MAX_VERDICT NF_STOP
 
+/* we overload the higher bits for encoding auxiliary data such as the queue
+ * number. Not nice, but better than additional function arguments. */
+#define NF_VERDICT_MASK 0x0000ffff
+#define NF_VERDICT_BITS 16
+
+#define NF_VERDICT_QMASK 0xffff0000
+#define NF_VERDICT_QBITS 16
+
+#define NF_QUEUE_NR(x) ((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK || NF_QUEUE)
+
 /* only for userspace compatibility */
 #ifndef __KERNEL__
 /* Generic cache responses from hook functions.
@@ -179,10 +189,12 @@ int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
 
 /* Packet queuing */
 typedef int (*nf_queue_outfn_t)(struct sk_buff *skb, 
-                                struct nf_info *info, void *data);
+                                struct nf_info *info,
+				unsigned int queuenum, void *data);
 extern int nf_register_queue_handler(int pf, 
                                      nf_queue_outfn_t outfn, void *data);
 extern int nf_unregister_queue_handler(int pf);
+extern void nf_unregister_queue_handlers(nf_queue_outfn_t outfn);
 extern void nf_reinject(struct sk_buff *skb,
 			struct nf_info *info,
 			unsigned int verdict);