[net-next-2.6.git] / net / ipv4 / netfilter / ip_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 <net/route.h>

#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv4/ip_conntrack.h>
#include <linux/netfilter_ipv4/ip_conntrack_helper.h>

#define NMBD_PORT	137

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

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

static int help(struct sk_buff **pskb,
                struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
{
	struct ip_conntrack_expect *exp;
	struct iphdr *iph = (*pskb)->nh.iph;
	struct rtable *rt = (struct rtable *)(*pskb)->dst;
	struct in_device *in_dev;
	__be32 mask = 0;

	/* we're only interested in locally generated packets */
	if ((*pskb)->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->u.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 = ip_conntrack_expect_alloc(ct);
	if (exp == NULL)
		goto out;

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

	exp->mask.src.ip          = mask;
	exp->mask.src.u.udp.port  = 0xFFFF;
	exp->mask.dst.ip          = 0xFFFFFFFF;
	exp->mask.dst.u.udp.port  = 0xFFFF;
	exp->mask.dst.protonum    = 0xFF;

	exp->expectfn             = NULL;
	exp->flags                = IP_CT_EXPECT_PERMANENT;

	ip_conntrack_expect_related(exp);
	ip_conntrack_expect_put(exp);

	ip_ct_refresh(ct, *pskb, timeout * HZ);
out:
	return NF_ACCEPT;
}

static struct ip_conntrack_helper helper = {
	.name			= "netbios-ns",
	.tuple = {
		.src = {
			.u = {
				.udp = {
					.port	= __constant_htons(NMBD_PORT),
				}
			}
		},
		.dst = {
			.protonum	= IPPROTO_UDP,
		},
	},
	.mask = {
		.src = {
			.u = {
				.udp = {
					.port	= 0xFFFF,
				}
			}
		},
		.dst = {
			.protonum	= 0xFF,
		},
	},
	.max_expected		= 1,
	.me			= THIS_MODULE,
	.help			= help,
};

static int __init ip_conntrack_netbios_ns_init(void)
{
	helper.timeout = timeout;
	return ip_conntrack_helper_register(&helper);
}

static void __exit ip_conntrack_netbios_ns_fini(void)
{
	ip_conntrack_helper_unregister(&helper);
}

module_init(ip_conntrack_netbios_ns_init);
module_exit(ip_conntrack_netbios_ns_fini);
Commit	Line	Data
a2978aea PM	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>
8584d6df	24	#include <linux/if_addr.h>
a2978aea PM	25	#include <linux/in.h>
a2978aea PM	26	#include <linux/ip.h>
a2978aea PM	27	#include <net/route.h>
	28
	29	#include <linux/netfilter.h>
	30	#include <linux/netfilter_ipv4.h>
	31	#include <linux/netfilter_ipv4/ip_conntrack.h>
	32	#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
	33
e7fa1bd9 PM	34	#define NMBD_PORT 137
e7fa1bd9 PM	35
a2978aea PM	36	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
	37	MODULE_DESCRIPTION("NetBIOS name service broadcast connection tracking helper");
	38	MODULE_LICENSE("GPL");
	39
	40	static unsigned int timeout = 3;
e7be6994	41	module_param(timeout, uint, 0400);
a2978aea PM	42	MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds");
	43
	44	static int help(struct sk_buff **pskb,
	45	struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
	46	{
	47	struct ip_conntrack_expect *exp;
	48	struct iphdr iph = (pskb)->nh.iph;
a2978aea PM	49	struct rtable rt = (struct rtable )(*pskb)->dst;
a2978aea PM	50	struct in_device *in_dev;
a144ea4b	51	__be32 mask = 0;
a2978aea PM	52
	53	/* we're only interested in locally generated packets */
	54	if ((*pskb)->sk == NULL)
	55	goto out;
	56	if (rt == NULL \|\| !(rt->rt_flags & RTCF_BROADCAST))
	57	goto out;
	58	if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
	59	goto out;
	60
	61	rcu_read_lock();
e5ed6399	62	in_dev = __in_dev_get_rcu(rt->u.dst.dev);
a2978aea PM	63	if (in_dev != NULL) {
	64	for_primary_ifa(in_dev) {
	65	if (ifa->ifa_broadcast == iph->daddr) {
	66	mask = ifa->ifa_mask;
	67	break;
	68	}
	69	} endfor_ifa(in_dev);
	70	}
	71	rcu_read_unlock();
	72
	73	if (mask == 0)
	74	goto out;
	75
a2978aea PM	76	exp = ip_conntrack_expect_alloc(ct);
	77	if (exp == NULL)
	78	goto out;
a2978aea	79
e7fa1bd9 PM	80	exp->tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
	81	exp->tuple.src.u.udp.port = ntohs(NMBD_PORT);
	82
a2978aea	83	exp->mask.src.ip = mask;
e7fa1bd9	84	exp->mask.src.u.udp.port = 0xFFFF;
a2978aea PM	85	exp->mask.dst.ip = 0xFFFFFFFF;
	86	exp->mask.dst.u.udp.port = 0xFFFF;
	87	exp->mask.dst.protonum = 0xFF;
	88
	89	exp->expectfn = NULL;
	90	exp->flags = IP_CT_EXPECT_PERMANENT;
	91
	92	ip_conntrack_expect_related(exp);
	93	ip_conntrack_expect_put(exp);
	94
1dfbab59	95	ip_ct_refresh(ct, pskb, timeout HZ);
a2978aea PM	96	out:
	97	return NF_ACCEPT;
	98	}
	99
	100	static struct ip_conntrack_helper helper = {
	101	.name = "netbios-ns",
	102	.tuple = {
3a934815 AM	103	.src = {
	104	.u = {
	105	.udp = {
e7fa1bd9	106	.port = __constant_htons(NMBD_PORT),
3a934815 AM	107	}
	108	}
	109	},
	110	.dst = {
	111	.protonum = IPPROTO_UDP,
	112	},
a2978aea PM	113	},
a2978aea PM	114	.mask = {
3a934815 AM	115	.src = {
	116	.u = {
	117	.udp = {
	118	.port = 0xFFFF,
	119	}
	120	}
	121	},
	122	.dst = {
	123	.protonum = 0xFF,
	124	},
a2978aea PM	125	},
	126	.max_expected = 1,
	127	.me = THIS_MODULE,
	128	.help = help,
	129	};
	130
65b4b4e8	131	static int __init ip_conntrack_netbios_ns_init(void)
a2978aea PM	132	{
	133	helper.timeout = timeout;
	134	return ip_conntrack_helper_register(&helper);
	135	}
	136
65b4b4e8	137	static void __exit ip_conntrack_netbios_ns_fini(void)
a2978aea PM	138	{
	139	ip_conntrack_helper_unregister(&helper);
	140	}
	141
65b4b4e8 AM	142	module_init(ip_conntrack_netbios_ns_init);
65b4b4e8 AM	143	module_exit(ip_conntrack_netbios_ns_fini);