[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, 63 insertions, 0 deletions

diff --git a/include/linux/netfilter/xt_conntrack.h b/include/linux/netfilter/xt_conntrack.h
new file mode 100644
index 000000000000..34f63cf2e293
--- /dev/null
+++ b/include/linux/netfilter/xt_conntrack.h
@@ -0,0 +1,63 @@
+/* Header file for kernel module to match connection tracking information.
+ * GPL (C) 2001  Marc Boucher (marc@mbsi.ca).
+ */
+
+#ifndef _XT_CONNTRACK_H
+#define _XT_CONNTRACK_H
+
+#include <linux/netfilter/nf_conntrack_tuple_common.h>
+#include <linux/in.h>
+
+#define XT_CONNTRACK_STATE_BIT(ctinfo) (1 << ((ctinfo)%IP_CT_IS_REPLY+1))
+#define XT_CONNTRACK_STATE_INVALID (1 << 0)
+
+#define XT_CONNTRACK_STATE_SNAT (1 << (IP_CT_NUMBER + 1))
+#define XT_CONNTRACK_STATE_DNAT (1 << (IP_CT_NUMBER + 2))
+#define XT_CONNTRACK_STATE_UNTRACKED (1 << (IP_CT_NUMBER + 3))
+
+/* flags, invflags: */
+#define XT_CONNTRACK_STATE	0x01
+#define XT_CONNTRACK_PROTO	0x02
+#define XT_CONNTRACK_ORIGSRC	0x04
+#define XT_CONNTRACK_ORIGDST	0x08
+#define XT_CONNTRACK_REPLSRC	0x10
+#define XT_CONNTRACK_REPLDST	0x20
+#define XT_CONNTRACK_STATUS	0x40
+#define XT_CONNTRACK_EXPIRES	0x80
+
+/* This is exposed to userspace, so remains frozen in time. */
+struct ip_conntrack_old_tuple
+{
+	struct {
+		__u32 ip;
+		union {
+			__u16 all;
+		} u;
+	} src;
+
+	struct {
+		__u32 ip;
+		union {
+			__u16 all;
+		} u;
+
+		/* The protocol. */
+		u16 protonum;
+	} dst;
+};
+
+struct xt_conntrack_info
+{
+	unsigned int statemask, statusmask;
+
+	struct ip_conntrack_old_tuple tuple[IP_CT_DIR_MAX];
+	struct in_addr sipmsk[IP_CT_DIR_MAX], dipmsk[IP_CT_DIR_MAX];
+
+	unsigned long expires_min, expires_max;
+
+	/* Flags word */
+	u_int8_t flags;
+	/* Inverse flags */
+	u_int8_t invflags;
+};
+#endif /*_XT_CONNTRACK_H*/