[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>

2 files changed, 24 insertions, 10 deletions

diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index d163e20ca8d9..711e05f33d68 100644
--- a/include/linux/netfilter.h
+++ b/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);
diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h
index ace7a7be0742..561f9df28808 100644
--- a/include/linux/netfilter/nfnetlink.h
+++ b/include/linux/netfilter/nfnetlink.h
@@ -69,15 +69,14 @@ struct nfgenmsg {
 #define NFNL_SUBSYS_ID(x)       ((x & 0xff00) >> 8)
 #define NFNL_MSG_TYPE(x)        (x & 0x00ff)
 
-enum nfnl_subsys_id {
-        NFNL_SUBSYS_NONE = 0,
-        NFNL_SUBSYS_CTNETLINK,
-        NFNL_SUBSYS_CTNETLINK_EXP,
-        NFNL_SUBSYS_IPTNETLINK,
-        NFNL_SUBSYS_QUEUE,
-        NFNL_SUBSYS_ULOG,
-        NFNL_SUBSYS_COUNT,
-};
+/* No enum here, otherwise __stringify() trick of MODULE_ALIAS_NFNL_SUBSYS()
+ * won't work anymore */
+#define NFNL_SUBSYS_NONE                0
+#define NFNL_SUBSYS_CTNETLINK           1
+#define NFNL_SUBSYS_CTNETLINK_EXP       2
+#define NFNL_SUBSYS_QUEUE               3
+#define NFNL_SUBSYS_ULOG                4
+#define NFNL_SUBSYS_COUNT               5
 
 #ifdef __KERNEL__
 
@@ -142,5 +141,8 @@ extern int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group,
                           int echo);
 extern int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags);
 
+#define MODULE_ALIAS_NFNL_SUBSYS(subsys) \
+        MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys))
+
 #endif  /* __KERNEL__ */
 #endif  /* _NFNETLINK_H */