[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, 107 insertions, 0 deletions

diff --git a/net/netfilter/xt_NFQUEUE.c b/net/netfilter/xt_NFQUEUE.c
new file mode 100644
index 00000000000..8b76b6f8d1e
--- /dev/null
+++ b/net/netfilter/xt_NFQUEUE.c
@@ -0,0 +1,107 @@
+/* iptables module for using new netfilter netlink queue
+ *
+ * (C) 2005 by Harald Welte <laforge@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as 
+ * published by the Free Software Foundation.
+ * 
+ */
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter_arp.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_NFQUEUE.h>
+
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_DESCRIPTION("[ip,ip6,arp]_tables NFQUEUE target");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_NFQUEUE");
+MODULE_ALIAS("ip6t_NFQUEUE");
+MODULE_ALIAS("arpt_NFQUEUE");
+
+static unsigned int
+target(struct sk_buff **pskb,
+       const struct net_device *in,
+       const struct net_device *out,
+       unsigned int hooknum,
+       const void *targinfo,
+       void *userinfo)
+{
+	const struct xt_NFQ_info *tinfo = targinfo;
+
+	return NF_QUEUE_NR(tinfo->queuenum);
+}
+
+static int
+checkentry(const char *tablename,
+	   const void *entry,
+           void *targinfo,
+           unsigned int targinfosize,
+           unsigned int hook_mask)
+{
+	if (targinfosize != XT_ALIGN(sizeof(struct xt_NFQ_info))) {
+		printk(KERN_WARNING "NFQUEUE: targinfosize %u != %Zu\n",
+		       targinfosize,
+		       XT_ALIGN(sizeof(struct xt_NFQ_info)));
+		return 0;
+	}
+
+	return 1;
+}
+
+static struct xt_target ipt_NFQ_reg = {
+	.name		= "NFQUEUE",
+	.target		= target,
+	.checkentry	= checkentry,
+	.me		= THIS_MODULE,
+};
+
+static struct xt_target ip6t_NFQ_reg = {
+	.name		= "NFQUEUE",
+	.target		= target,
+	.checkentry	= checkentry,
+	.me		= THIS_MODULE,
+};
+
+static struct xt_target arpt_NFQ_reg = {
+	.name		= "NFQUEUE",
+	.target		= target,
+	.checkentry	= checkentry,
+	.me		= THIS_MODULE,
+};
+
+static int __init init(void)
+{
+	int ret;
+	ret = xt_register_target(AF_INET, &ipt_NFQ_reg);
+	if (ret)
+		return ret;
+	ret = xt_register_target(AF_INET6, &ip6t_NFQ_reg);
+	if (ret)
+		goto out_ip;
+	ret = xt_register_target(NF_ARP, &arpt_NFQ_reg);
+	if (ret)
+		goto out_ip6;
+
+	return ret;
+out_ip6:
+	xt_unregister_target(AF_INET6, &ip6t_NFQ_reg);
+out_ip:
+	xt_unregister_target(AF_INET, &ipt_NFQ_reg);
+
+	return ret;
+}
+
+static void __exit fini(void)
+{
+	xt_unregister_target(NF_ARP, &arpt_NFQ_reg);
+	xt_unregister_target(AF_INET6, &ip6t_NFQ_reg);
+	xt_unregister_target(AF_INET, &ipt_NFQ_reg);
+}
+
+module_init(init);
+module_exit(fini);