netfilter: xt_hashlimit: Create revision 2 to support higher pps rates

Create a new revision for the hashlimit iptables extension module. Rev 2
will support higher pps of upto 1 million, Version 1 supports only 10k.

To support this we have to increase the size of the variables avg and
burst in hashlimit_cfg to 64-bit. Create two new structs hashlimit_cfg2
and xt_hashlimit_mtinfo2 and also create newer versions of all the
functions for match, checkentry and destroy.

Some of the functions like hashlimit_mt, hashlimit_mt_check etc are very
similar in both rev1 and rev2 with only minor changes, so I have split
those functions and moved all the common code to a *_common function.
Signed-off-by: Vishwanath Pai <vpai@akamai.com>
Signed-off-by: Joshua Hunt <johunt@akamai.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/uapi/linux/netfilter/xt_hashlimit.h

@@ -6,6 +6,7 @@
 
 /* timings are in milliseconds. */
 #define XT_HASHLIMIT_SCALE 10000
+#define XT_HASHLIMIT_SCALE_v2 1000000llu
 /* 1/10,000 sec period => max of 10,000/sec.  Min rate is then 429490
  * seconds, or one packet every 59 hours.
  */
@@ -63,6 +64,20 @@ struct hashlimit_cfg1 {
 	__u8 srcmask, dstmask;
 };
 
+struct hashlimit_cfg2 {
+	__u64 avg;		/* Average secs between packets * scale */
+	__u64 burst;		/* Period multiplier for upper limit. */
+	__u32 mode;		/* bitmask of XT_HASHLIMIT_HASH_* */
+
+	/* user specified */
+	__u32 size;		/* how many buckets */
+	__u32 max;		/* max number of entries */
+	__u32 gc_interval;	/* gc interval */
+	__u32 expire;		/* when do entries expire? */
+
+	__u8 srcmask, dstmask;
+};
+
 struct xt_hashlimit_mtinfo1 {
 	char name[IFNAMSIZ];
 	struct hashlimit_cfg1 cfg;
@@ -71,4 +86,12 @@ struct xt_hashlimit_mtinfo1 {
 	struct xt_hashlimit_htable *hinfo __attribute__((aligned(8)));
 };
 
+struct xt_hashlimit_mtinfo2 {
+	char name[NAME_MAX];
+	struct hashlimit_cfg2 cfg;
+
+	/* Used internally by the kernel */
+	struct xt_hashlimit_htable *hinfo __attribute__((aligned(8)));
+};
+
 #endif /* _UAPI_XT_HASHLIMIT_H */