[net-next-2.6.git] / net / netfilter / nf_conntrack_netbios_ns.c

/*
 *      NetBIOS name service broadcast connection tracking helper
 *
 *      (c) 2005 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
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */
/*
 *      This helper tracks locally originating NetBIOS name service
 *      requests by issuing permanent expectations (valid until
 *      timing out) matching all reply connections from the
 *      destination network. The only NetBIOS specific thing is
 *      actually the port number.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/if_addr.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/netfilter.h>
#include <net/route.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_expect.h>

#define NMBD_PORT	137

MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("NetBIOS name service broadcast connection tracking helper");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ip_conntrack_netbios_ns");
MODULE_ALIAS_NFCT_HELPER("netbios_ns");

static unsigned int timeout __read_mostly = 3;
module_param(timeout, uint, 0400);
MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds");

static int help(struct sk_buff *skb, unsigned int protoff,
		struct nf_conn *ct, enum ip_conntrack_info ctinfo)
{
	struct nf_conntrack_expect *exp;
	struct iphdr *iph = ip_hdr(skb);
	struct rtable *rt = skb_rtable(skb);
	struct in_device *in_dev;
	__be32 mask = 0;

	/* we're only interested in locally generated packets */
	if (skb->sk == NULL)
		goto out;
	if (rt == NULL || !(rt->rt_flags & RTCF_BROADCAST))
		goto out;
	if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
		goto out;

	rcu_read_lock();
	in_dev = __in_dev_get_rcu(rt->dst.dev);
	if (in_dev != NULL) {
		for_primary_ifa(in_dev) {
			if (ifa->ifa_broadcast == iph->daddr) {
				mask = ifa->ifa_mask;
				break;
			}
		} endfor_ifa(in_dev);
	}
	rcu_read_unlock();

	if (mask == 0)
		goto out;

	exp = nf_ct_expect_alloc(ct);
	if (exp == NULL)
		goto out;

	exp->tuple                = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
	exp->tuple.src.u.udp.port = htons(NMBD_PORT);

	exp->mask.src.u3.ip       = mask;
	exp->mask.src.u.udp.port  = htons(0xFFFF);

	exp->expectfn             = NULL;
	exp->flags                = NF_CT_EXPECT_PERMANENT;
	exp->class		  = NF_CT_EXPECT_CLASS_DEFAULT;
	exp->helper               = NULL;

	nf_ct_expect_related(exp);
	nf_ct_expect_put(exp);

	nf_ct_refresh(ct, skb, timeout * HZ);
out:
	return NF_ACCEPT;
}

static struct nf_conntrack_expect_policy exp_policy = {
	.max_expected	= 1,
};

static struct nf_conntrack_helper helper __read_mostly = {
	.name			= "netbios-ns",
	.tuple.src.l3num	= AF_INET,
	.tuple.src.u.udp.port	= cpu_to_be16(NMBD_PORT),
	.tuple.dst.protonum	= IPPROTO_UDP,
	.me			= THIS_MODULE,
	.help			= help,
	.expect_policy		= &exp_policy,
};

static int __init nf_conntrack_netbios_ns_init(void)
{
	exp_policy.timeout = timeout;
	return nf_conntrack_helper_register(&helper);
}

static void __exit nf_conntrack_netbios_ns_fini(void)
{
	nf_conntrack_helper_unregister(&helper);
}

module_init(nf_conntrack_netbios_ns_init);
module_exit(nf_conntrack_netbios_ns_fini);
Commit	Line	Data
	1	/*
	2	* NetBIOS name service broadcast connection tracking helper
	3	*
	4	* (c) 2005 Patrick McHardy <kaber@trash.net>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11	/*
	12	* This helper tracks locally originating NetBIOS name service
	13	* requests by issuing permanent expectations (valid until
	14	* timing out) matching all reply connections from the
	15	* destination network. The only NetBIOS specific thing is
	16	* actually the port number.
	17	*/
	18	#include <linux/kernel.h>
	19	#include <linux/module.h>
	20	#include <linux/init.h>
	21	#include <linux/skbuff.h>
	22	#include <linux/netdevice.h>
	23	#include <linux/inetdevice.h>
	24	#include <linux/if_addr.h>
	25	#include <linux/in.h>
	26	#include <linux/ip.h>
	27	#include <linux/netfilter.h>
	28	#include <net/route.h>
	29
	30	#include <net/netfilter/nf_conntrack.h>
	31	#include <net/netfilter/nf_conntrack_helper.h>
	32	#include <net/netfilter/nf_conntrack_expect.h>
	33
	34	#define NMBD_PORT 137
	35
	36	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
	37	MODULE_DESCRIPTION("NetBIOS name service broadcast connection tracking helper");
	38	MODULE_LICENSE("GPL");
	39	MODULE_ALIAS("ip_conntrack_netbios_ns");
	40	MODULE_ALIAS_NFCT_HELPER("netbios_ns");
	41
	42	static unsigned int timeout __read_mostly = 3;
	43	module_param(timeout, uint, 0400);
	44	MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds");
	45
	46	static int help(struct sk_buff *skb, unsigned int protoff,
	47	struct nf_conn *ct, enum ip_conntrack_info ctinfo)
	48	{
	49	struct nf_conntrack_expect *exp;
	50	struct iphdr *iph = ip_hdr(skb);
	51	struct rtable *rt = skb_rtable(skb);
	52	struct in_device *in_dev;
	53	__be32 mask = 0;
	54
	55	/* we're only interested in locally generated packets */
	56	if (skb->sk == NULL)
	57	goto out;
	58	if (rt == NULL \|\| !(rt->rt_flags & RTCF_BROADCAST))
	59	goto out;
	60	if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
	61	goto out;
	62
	63	rcu_read_lock();
	64	in_dev = __in_dev_get_rcu(rt->dst.dev);
	65	if (in_dev != NULL) {
	66	for_primary_ifa(in_dev) {
	67	if (ifa->ifa_broadcast == iph->daddr) {
	68	mask = ifa->ifa_mask;
	69	break;
	70	}
	71	} endfor_ifa(in_dev);
	72	}
	73	rcu_read_unlock();
	74
	75	if (mask == 0)
	76	goto out;
	77
	78	exp = nf_ct_expect_alloc(ct);
	79	if (exp == NULL)
	80	goto out;
	81
	82	exp->tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
	83	exp->tuple.src.u.udp.port = htons(NMBD_PORT);
	84
	85	exp->mask.src.u3.ip = mask;
	86	exp->mask.src.u.udp.port = htons(0xFFFF);
	87
	88	exp->expectfn = NULL;
	89	exp->flags = NF_CT_EXPECT_PERMANENT;
	90	exp->class = NF_CT_EXPECT_CLASS_DEFAULT;
	91	exp->helper = NULL;
	92
	93	nf_ct_expect_related(exp);
	94	nf_ct_expect_put(exp);
	95
	96	nf_ct_refresh(ct, skb, timeout * HZ);
	97	out:
	98	return NF_ACCEPT;
	99	}
	100
	101	static struct nf_conntrack_expect_policy exp_policy = {
	102	.max_expected = 1,
	103	};
	104
	105	static struct nf_conntrack_helper helper __read_mostly = {
	106	.name = "netbios-ns",
	107	.tuple.src.l3num = AF_INET,
	108	.tuple.src.u.udp.port = cpu_to_be16(NMBD_PORT),
	109	.tuple.dst.protonum = IPPROTO_UDP,
	110	.me = THIS_MODULE,
	111	.help = help,
	112	.expect_policy = &exp_policy,
	113	};
	114
	115	static int __init nf_conntrack_netbios_ns_init(void)
	116	{
	117	exp_policy.timeout = timeout;
	118	return nf_conntrack_helper_register(&helper);
	119	}
	120
	121	static void __exit nf_conntrack_netbios_ns_fini(void)
	122	{
	123	nf_conntrack_helper_unregister(&helper);
	124	}
	125
	126	module_init(nf_conntrack_netbios_ns_init);
	127	module_exit(nf_conntrack_netbios_ns_fini);