netfilter: xtables: "set" match and "SET" target support

The patch adds the combined module of the "SET" target and "set" match
to netfilter. Both the previous and the current revisions are supported.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>

include/linux/netfilter/xt_set.h

@@ -0,0 +1,55 @@
+#ifndef _XT_SET_H
+#define _XT_SET_H
+
+#include <linux/netfilter/ipset/ip_set.h>
+
+/* Revision 0 interface: backward compatible with netfilter/iptables */
+
+/*
+ * Option flags for kernel operations (xt_set_info_v0)
+ */
+#define IPSET_SRC		0x01	/* Source match/add */
+#define IPSET_DST		0x02	/* Destination match/add */
+#define IPSET_MATCH_INV		0x04	/* Inverse matching */
+
+struct xt_set_info_v0 {
+	ip_set_id_t index;
+	union {
+		__u32 flags[IPSET_DIM_MAX + 1];
+		struct {
+			__u32 __flags[IPSET_DIM_MAX];
+			__u8 dim;
+			__u8 flags;
+		} compat;
+	} u;
+};
+
+/* match and target infos */
+struct xt_set_info_match_v0 {
+	struct xt_set_info_v0 match_set;
+};
+
+struct xt_set_info_target_v0 {
+	struct xt_set_info_v0 add_set;
+	struct xt_set_info_v0 del_set;
+};
+
+/* Revision 1: current interface to netfilter/iptables */
+
+struct xt_set_info {
+	ip_set_id_t index;
+	__u8 dim;
+	__u8 flags;
+};
+
+/* match and target infos */
+struct xt_set_info_match {
+	struct xt_set_info match_set;
+};
+
+struct xt_set_info_target {
+	struct xt_set_info add_set;
+	struct xt_set_info del_set;
+};
+
+#endif /*_XT_SET_H*/

net/netfilter/Kconfig

@@ -352,6 +352,18 @@ config NETFILTER_XT_CONNMARK
 	ctmark), similarly to the packet mark (nfmark). Using this
 	target and match, you can set and match on this mark.
 
+config NETFILTER_XT_SET
+	tristate 'set target and match support'
+	depends on IP_SET
+	depends on NETFILTER_ADVANCED
+	help
+	  This option adds the "SET" target and "set" match.
+
+	  Using this target and match, you can add/delete and match
+	  elements in the sets created by ipset(8).
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 # alphabetically ordered list of targets
 
 comment "Xtables targets"

net/netfilter/Makefile

@@ -46,6 +46,7 @@ obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
 # combos
 obj-$(CONFIG_NETFILTER_XT_MARK) += xt_mark.o
 obj-$(CONFIG_NETFILTER_XT_CONNMARK) += xt_connmark.o
+obj-$(CONFIG_NETFILTER_XT_SET) += xt_set.o
 
 # targets
 obj-$(CONFIG_NETFILTER_XT_TARGET_AUDIT) += xt_AUDIT.o