[NETFILTER]: Add addrtype match

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@redhat.com>

include/linux/netfilter_ipv4/ipt_addrtype.h

+#ifndef _IPT_ADDRTYPE_H
+#define _IPT_ADDRTYPE_H
+
+struct ipt_addrtype_info {
+	u_int16_t	source;		/* source-type mask */
+	u_int16_t	dest;		/* dest-type mask */
+	u_int32_t	invert_source;
+	u_int32_t	invert_dest;
+};
+
+#endif

net/ipv4/netfilter/Kconfig

@@ -603,5 +603,15 @@ config IP_NF_RAW
 	  <file:Documentation/modules.txt>.  If unsure, say `N'.
 	  help
 
+config IP_NF_MATCH_ADDRTYPE
+	tristate  'address type match support'
+	depends on IP_NF_IPTABLES
+	help
+	  This option allows you to match what routing thinks of an address,
+	  eg. UNICAST, LOCAL, BROADCAST, ...
+	
+	  If you want to compile it as a module, say M here and read
+	  Documentation/modules.txt.  If unsure, say `N'.
+
 endmenu
 

net/ipv4/netfilter/Makefile

@@ -64,6 +64,7 @@ obj-$(CONFIG_IP_NF_MATCH_TTL) += ipt_ttl.o
 obj-$(CONFIG_IP_NF_MATCH_STATE) += ipt_state.o
 obj-$(CONFIG_IP_NF_MATCH_CONNTRACK) += ipt_conntrack.o
 obj-$(CONFIG_IP_NF_MATCH_TCPMSS) += ipt_tcpmss.o
+obj-$(CONFIG_IP_NF_MATCH_ADDRTYPE) += ipt_addrtype.o
 
 obj-$(CONFIG_IP_NF_MATCH_PHYSDEV) += ipt_physdev.o
 

net/ipv4/netfilter/ipt_addrtype.c

+/*
+ *  iptables module to match inet_addr_type() of an ip.
+ *
+ *  Copyright (c) 2004 Patrick McHardy <kaber@trash.net>
+ *
+ *  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/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/ip.h>
+#include <net/route.h>
+
+#include <linux/netfilter_ipv4/ipt_addrtype.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("iptables addrtype match");
+
+static inline int match_type(u_int32_t addr, u_int16_t mask)
+{
+	return !!(mask & (1 << inet_addr_type(addr)));
+}
+
+static int match(const struct sk_buff *skb, const struct net_device *in,
+		 const struct net_device *out, const void *matchinfo,
+		 int offset, int *hotdrop)
+{
+	const struct ipt_addrtype_info *info = matchinfo;
+	const struct iphdr *iph = skb->nh.iph;
+	int ret = 1;
+
+	if (info->source)
+		ret &= match_type(iph->saddr, info->source)^info->invert_source;
+	if (info->dest)
+		ret &= match_type(iph->daddr, info->dest)^info->invert_dest;
+	
+	return ret;
+}
+
+static int checkentry(const char *tablename, const struct ipt_ip *ip,
+		      void *matchinfo, unsigned int matchsize,
+		      unsigned int hook_mask)
+{
+	if (matchsize != IPT_ALIGN(sizeof(struct ipt_addrtype_info))) {
+		printk(KERN_ERR "ipt_addrtype: invalid size (%u != %u)\n.",
+		       matchsize, IPT_ALIGN(sizeof(struct ipt_addrtype_info)));
+		return 0;
+	}
+
+	return 1;
+}
+
+static struct ipt_match addrtype_match = {
+	.name		= "addrtype",
+	.match		= match,
+	.checkentry	= checkentry,
+	.me		= THIS_MODULE
+};
+
+static int __init init(void)
+{
+	return ipt_register_match(&addrtype_match);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_match(&addrtype_match);
+}
+
+module_init(init);
+module_exit(fini);