[NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables

This monster-patch tries to do the best job for unifying the data
structures and backend interfaces for the three evil clones ip_tables,
ip6_tables and arp_tables.  In an ideal world we would never have
allowed this kind of copy+paste programming... but well, our world
isn't (yet?) ideal.

o introduce a new x_tables module
o {ip,arp,ip6}_tables depend on this x_tables module
o registration functions for tables, matches and targets are only
  wrappers around x_tables provided functions
o all matches/targets that are used from ip_tables and ip6_tables
  are now implemented as xt_FOOBAR.c files and provide module aliases
  to ipt_FOOBAR and ip6t_FOOBAR
o header files for xt_matches are in include/linux/netfilter/,
  include/linux/netfilter_{ipv4,ipv6} contains compatibility wrappers
  around the xt_FOOBAR.h headers

Based on this patchset we're going to further unify the code,
gradually getting rid of all the layer 3 specific assumptions.

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

1 files changed, 21 insertions, 0 deletions

diff --git a/include/linux/netfilter/xt_limit.h b/include/linux/netfilter/xt_limit.h
new file mode 100644
index 0000000000000..b3ce65375ecb7
--- /dev/null
+++ b/include/linux/netfilter/xt_limit.h
@@ -0,0 +1,21 @@
+#ifndef _XT_RATE_H
+#define _XT_RATE_H
+
+/* timings are in milliseconds. */
+#define XT_LIMIT_SCALE 10000
+
+/* 1/10,000 sec period => max of 10,000/sec.  Min rate is then 429490
+   seconds, or one every 59 hours. */
+struct xt_rateinfo {
+	u_int32_t avg;    /* Average secs between packets * scale */
+	u_int32_t burst;  /* Period multiplier for upper limit. */
+
+	/* Used internally by the kernel */
+	unsigned long prev;
+	u_int32_t credit;
+	u_int32_t credit_cap, cost;
+
+	/* Ugly, ugly fucker. */
+	struct xt_rateinfo *master;
+};
+#endif /*_XT_RATE_H*/