[deliverable/linux.git] / net / netfilter / xt_conntrack.c

/*
 *	xt_conntrack - Netfilter module to match connection tracking
 *	information. (Superset of Rusty's minimalistic state match.)
 *
 *	(C) 2001  Marc Boucher (marc@mbsi.ca).
 *	Copyright © CC Computer Consultants GmbH, 2007 - 2008
 *
 *	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 <net/ipv6.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_conntrack.h>
#include <net/netfilter/nf_conntrack.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
MODULE_DESCRIPTION("Xtables: connection tracking state match");
MODULE_ALIAS("ipt_conntrack");
MODULE_ALIAS("ip6t_conntrack");

static bool
conntrack_addrcmp(const union nf_inet_addr *kaddr,
                  const union nf_inet_addr *uaddr,
                  const union nf_inet_addr *umask, unsigned int l3proto)
{
	if (l3proto == NFPROTO_IPV4)
		return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
	else if (l3proto == NFPROTO_IPV6)
		return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
		       &uaddr->in6) == 0;
	else
		return false;
}

static inline bool
conntrack_mt_origsrc(const struct nf_conn *ct,
                     const struct xt_conntrack_mtinfo2 *info,
		     u_int8_t family)
{
	return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
	       &info->origsrc_addr, &info->origsrc_mask, family);
}

static inline bool
conntrack_mt_origdst(const struct nf_conn *ct,
                     const struct xt_conntrack_mtinfo2 *info,
		     u_int8_t family)
{
	return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3,
	       &info->origdst_addr, &info->origdst_mask, family);
}

static inline bool
conntrack_mt_replsrc(const struct nf_conn *ct,
                     const struct xt_conntrack_mtinfo2 *info,
		     u_int8_t family)
{
	return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3,
	       &info->replsrc_addr, &info->replsrc_mask, family);
}

static inline bool
conntrack_mt_repldst(const struct nf_conn *ct,
                     const struct xt_conntrack_mtinfo2 *info,
		     u_int8_t family)
{
	return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3,
	       &info->repldst_addr, &info->repldst_mask, family);
}

static inline bool
ct_proto_port_check(const struct xt_conntrack_mtinfo2 *info,
                    const struct nf_conn *ct)
{
	const struct nf_conntrack_tuple *tuple;

	tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
	if ((info->match_flags & XT_CONNTRACK_PROTO) &&
	    (nf_ct_protonum(ct) == info->l4proto) ^
	    !(info->invert_flags & XT_CONNTRACK_PROTO))
		return false;

	/* Shortcut to match all recognized protocols by using ->src.all. */
	if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) &&
	    (tuple->src.u.all == info->origsrc_port) ^
	    !(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT))
		return false;

	if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) &&
	    (tuple->dst.u.all == info->origdst_port) ^
	    !(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT))
		return false;

	tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;

	if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) &&
	    (tuple->src.u.all == info->replsrc_port) ^
	    !(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT))
		return false;

	if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) &&
	    (tuple->dst.u.all == info->repldst_port) ^
	    !(info->invert_flags & XT_CONNTRACK_REPLDST_PORT))
		return false;

	return true;
}

static bool
conntrack_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
	const struct xt_conntrack_mtinfo2 *info = par->matchinfo;
	enum ip_conntrack_info ctinfo;
	const struct nf_conn *ct;
	unsigned int statebit;

	ct = nf_ct_get(skb, &ctinfo);

	if (ct == &nf_conntrack_untracked)
		statebit = XT_CONNTRACK_STATE_UNTRACKED;
	else if (ct != NULL)
		statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
	else
		statebit = XT_CONNTRACK_STATE_INVALID;

	if (info->match_flags & XT_CONNTRACK_STATE) {
		if (ct != NULL) {
			if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
				statebit |= XT_CONNTRACK_STATE_SNAT;
			if (test_bit(IPS_DST_NAT_BIT, &ct->status))
				statebit |= XT_CONNTRACK_STATE_DNAT;
		}
		if (!!(info->state_mask & statebit) ^
		    !(info->invert_flags & XT_CONNTRACK_STATE))
			return false;
	}

	if (ct == NULL)
		return info->match_flags & XT_CONNTRACK_STATE;
	if ((info->match_flags & XT_CONNTRACK_DIRECTION) &&
	    (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^
	    !!(info->invert_flags & XT_CONNTRACK_DIRECTION))
		return false;

	if (info->match_flags & XT_CONNTRACK_ORIGSRC)
		if (conntrack_mt_origsrc(ct, info, par->family) ^
		    !(info->invert_flags & XT_CONNTRACK_ORIGSRC))
			return false;

	if (info->match_flags & XT_CONNTRACK_ORIGDST)
		if (conntrack_mt_origdst(ct, info, par->family) ^
		    !(info->invert_flags & XT_CONNTRACK_ORIGDST))
			return false;

	if (info->match_flags & XT_CONNTRACK_REPLSRC)
		if (conntrack_mt_replsrc(ct, info, par->family) ^
		    !(info->invert_flags & XT_CONNTRACK_REPLSRC))
			return false;

	if (info->match_flags & XT_CONNTRACK_REPLDST)
		if (conntrack_mt_repldst(ct, info, par->family) ^
		    !(info->invert_flags & XT_CONNTRACK_REPLDST))
			return false;

	if (!ct_proto_port_check(info, ct))
		return false;

	if ((info->match_flags & XT_CONNTRACK_STATUS) &&
	    (!!(info->status_mask & ct->status) ^
	    !(info->invert_flags & XT_CONNTRACK_STATUS)))
		return false;

	if (info->match_flags & XT_CONNTRACK_EXPIRES) {
		unsigned long expires = 0;

		if (timer_pending(&ct->timeout))
			expires = (ct->timeout.expires - jiffies) / HZ;
		if ((expires >= info->expires_min &&
		    expires <= info->expires_max) ^
		    !(info->invert_flags & XT_CONNTRACK_EXPIRES))
			return false;
	}
	return true;
}

static bool
conntrack_mt_v1(const struct sk_buff *skb, const struct xt_match_param *par)
{
	const struct xt_conntrack_mtinfo2 *const *info = par->matchinfo;
	struct xt_match_param newpar = *par;

	newpar.matchinfo = *info;
	return conntrack_mt(skb, &newpar);
}

static bool conntrack_mt_check(const struct xt_mtchk_param *par)
{
	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
		printk(KERN_WARNING "can't load conntrack support for "
				    "proto=%u\n", par->family);
		return false;
	}
	return true;
}

static bool conntrack_mt_check_v1(const struct xt_mtchk_param *par)
{
	struct xt_conntrack_mtinfo1 *info = par->matchinfo;
	struct xt_conntrack_mtinfo2 *up;
	int ret = conntrack_mt_check(par);

	if (ret < 0)
		return ret;

	up = kmalloc(sizeof(*up), GFP_KERNEL);
	if (up == NULL) {
		nf_ct_l3proto_module_put(par->family);
		return -ENOMEM;
	}

	/*
	 * The strategy here is to minimize the overhead of v1 matching,
	 * by prebuilding a v2 struct and putting the pointer into the
	 * v1 dataspace.
	 */
	memcpy(up, info, offsetof(typeof(*info), state_mask));
	up->state_mask  = info->state_mask;
	up->status_mask = info->status_mask;
	*(void **)info  = up;
	return true;
}

static void conntrack_mt_destroy(const struct xt_mtdtor_param *par)
{
	nf_ct_l3proto_module_put(par->family);
}

static void conntrack_mt_destroy_v1(const struct xt_mtdtor_param *par)
{
	struct xt_conntrack_mtinfo2 **info = par->matchinfo;
	kfree(*info);
	conntrack_mt_destroy(par);
}

static struct xt_match conntrack_mt_reg[] __read_mostly = {
	{
		.name       = "conntrack",
		.revision   = 1,
		.family     = NFPROTO_UNSPEC,
		.matchsize  = sizeof(struct xt_conntrack_mtinfo1),
		.match      = conntrack_mt_v1,
		.checkentry = conntrack_mt_check_v1,
		.destroy    = conntrack_mt_destroy_v1,
		.me         = THIS_MODULE,
	},
	{
		.name       = "conntrack",
		.revision   = 2,
		.family     = NFPROTO_UNSPEC,
		.matchsize  = sizeof(struct xt_conntrack_mtinfo2),
		.match      = conntrack_mt,
		.checkentry = conntrack_mt_check,
		.destroy    = conntrack_mt_destroy,
		.me         = THIS_MODULE,
	},
};

static int __init conntrack_mt_init(void)
{
	return xt_register_matches(conntrack_mt_reg,
	       ARRAY_SIZE(conntrack_mt_reg));
}

static void __exit conntrack_mt_exit(void)
{
	xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg));
}

module_init(conntrack_mt_init);
module_exit(conntrack_mt_exit);
Commit	Line	Data
64eb12f9 JE	1	/*
	2	* xt_conntrack - Netfilter module to match connection tracking
	3	* information. (Superset of Rusty's minimalistic state match.)
1da177e4	4	*
64eb12f9 JE	5	* (C) 2001 Marc Boucher (marc@mbsi.ca).
64eb12f9 JE	6	* Copyright © CC Computer Consultants GmbH, 2007 - 2008
1da177e4	7	*
64eb12f9 JE	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
1da177e4 LT	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/skbuff.h>
64eb12f9	15	#include <net/ipv6.h>
2e4e6a17 HW	16	#include <linux/netfilter/x_tables.h>
2e4e6a17 HW	17	#include <linux/netfilter/xt_conntrack.h>
587aa641	18	#include <net/netfilter/nf_conntrack.h>
1da177e4 LT	19
	20	MODULE_LICENSE("GPL");
	21	MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
9e05ec4b	22	MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
2ae15b64	23	MODULE_DESCRIPTION("Xtables: connection tracking state match");
2e4e6a17	24	MODULE_ALIAS("ipt_conntrack");
64eb12f9	25	MODULE_ALIAS("ip6t_conntrack");
1da177e4	26
64eb12f9 JE	27	static bool
	28	conntrack_addrcmp(const union nf_inet_addr *kaddr,
	29	const union nf_inet_addr *uaddr,
	30	const union nf_inet_addr *umask, unsigned int l3proto)
	31	{
ee999d8b	32	if (l3proto == NFPROTO_IPV4)
6556874d	33	return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
ee999d8b	34	else if (l3proto == NFPROTO_IPV6)
64eb12f9 JE	35	return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
	36	&uaddr->in6) == 0;
	37	else
	38	return false;
	39	}
	40
	41	static inline bool
	42	conntrack_mt_origsrc(const struct nf_conn *ct,
d6d3f08b	43	const struct xt_conntrack_mtinfo2 *info,
76108cea	44	u_int8_t family)
64eb12f9 JE	45	{
	46	return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
	47	&info->origsrc_addr, &info->origsrc_mask, family);
	48	}
	49
	50	static inline bool
	51	conntrack_mt_origdst(const struct nf_conn *ct,
d6d3f08b	52	const struct xt_conntrack_mtinfo2 *info,
76108cea	53	u_int8_t family)
64eb12f9 JE	54	{
	55	return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3,
	56	&info->origdst_addr, &info->origdst_mask, family);
	57	}
	58
	59	static inline bool
	60	conntrack_mt_replsrc(const struct nf_conn *ct,
d6d3f08b	61	const struct xt_conntrack_mtinfo2 *info,
76108cea	62	u_int8_t family)
64eb12f9 JE	63	{
	64	return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3,
	65	&info->replsrc_addr, &info->replsrc_mask, family);
	66	}
	67
	68	static inline bool
	69	conntrack_mt_repldst(const struct nf_conn *ct,
d6d3f08b	70	const struct xt_conntrack_mtinfo2 *info,
76108cea	71	u_int8_t family)
64eb12f9 JE	72	{
	73	return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3,
	74	&info->repldst_addr, &info->repldst_mask, family);
	75	}
	76
b4164998	77	static inline bool
d6d3f08b	78	ct_proto_port_check(const struct xt_conntrack_mtinfo2 *info,
b4164998 JE	79	const struct nf_conn *ct)
	80	{
	81	const struct nf_conntrack_tuple *tuple;
	82
	83	tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
	84	if ((info->match_flags & XT_CONNTRACK_PROTO) &&
5e8fbe2a	85	(nf_ct_protonum(ct) == info->l4proto) ^
b4164998 JE	86	!(info->invert_flags & XT_CONNTRACK_PROTO))
	87	return false;
	88
	89	/* Shortcut to match all recognized protocols by using ->src.all. */
	90	if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) &&
	91	(tuple->src.u.all == info->origsrc_port) ^
	92	!(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT))
	93	return false;
	94
	95	if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) &&
	96	(tuple->dst.u.all == info->origdst_port) ^
	97	!(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT))
	98	return false;
	99
	100	tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
	101
	102	if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) &&
	103	(tuple->src.u.all == info->replsrc_port) ^
	104	!(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT))
	105	return false;
	106
	107	if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) &&
	108	(tuple->dst.u.all == info->repldst_port) ^
	109	!(info->invert_flags & XT_CONNTRACK_REPLDST_PORT))
	110	return false;
	111
	112	return true;
	113	}
	114
64eb12f9	115	static bool
f7108a20	116	conntrack_mt(const struct sk_buff skb, const struct xt_match_param par)
64eb12f9	117	{
d6d3f08b	118	const struct xt_conntrack_mtinfo2 *info = par->matchinfo;
64eb12f9 JE	119	enum ip_conntrack_info ctinfo;
	120	const struct nf_conn *ct;
	121	unsigned int statebit;
	122
	123	ct = nf_ct_get(skb, &ctinfo);
	124
	125	if (ct == &nf_conntrack_untracked)
	126	statebit = XT_CONNTRACK_STATE_UNTRACKED;
	127	else if (ct != NULL)
	128	statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
	129	else
	130	statebit = XT_CONNTRACK_STATE_INVALID;
	131
	132	if (info->match_flags & XT_CONNTRACK_STATE) {
	133	if (ct != NULL) {
	134	if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
	135	statebit \|= XT_CONNTRACK_STATE_SNAT;
	136	if (test_bit(IPS_DST_NAT_BIT, &ct->status))
	137	statebit \|= XT_CONNTRACK_STATE_DNAT;
	138	}
d61f89e9	139	if (!!(info->state_mask & statebit) ^
64eb12f9 JE	140	!(info->invert_flags & XT_CONNTRACK_STATE))
	141	return false;
	142	}
	143
	144	if (ct == NULL)
	145	return info->match_flags & XT_CONNTRACK_STATE;
b4164998 JE	146	if ((info->match_flags & XT_CONNTRACK_DIRECTION) &&
	147	(CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^
	148	!!(info->invert_flags & XT_CONNTRACK_DIRECTION))
64eb12f9 JE	149	return false;
	150
	151	if (info->match_flags & XT_CONNTRACK_ORIGSRC)
92f3b2b1	152	if (conntrack_mt_origsrc(ct, info, par->family) ^
64eb12f9 JE	153	!(info->invert_flags & XT_CONNTRACK_ORIGSRC))
	154	return false;
	155
	156	if (info->match_flags & XT_CONNTRACK_ORIGDST)
92f3b2b1	157	if (conntrack_mt_origdst(ct, info, par->family) ^
64eb12f9 JE	158	!(info->invert_flags & XT_CONNTRACK_ORIGDST))
	159	return false;
	160
	161	if (info->match_flags & XT_CONNTRACK_REPLSRC)
92f3b2b1	162	if (conntrack_mt_replsrc(ct, info, par->family) ^
64eb12f9 JE	163	!(info->invert_flags & XT_CONNTRACK_REPLSRC))
	164	return false;
	165
	166	if (info->match_flags & XT_CONNTRACK_REPLDST)
92f3b2b1	167	if (conntrack_mt_repldst(ct, info, par->family) ^
64eb12f9 JE	168	!(info->invert_flags & XT_CONNTRACK_REPLDST))
	169	return false;
	170
b4164998 JE	171	if (!ct_proto_port_check(info, ct))
	172	return false;
	173
64eb12f9 JE	174	if ((info->match_flags & XT_CONNTRACK_STATUS) &&
	175	(!!(info->status_mask & ct->status) ^
	176	!(info->invert_flags & XT_CONNTRACK_STATUS)))
	177	return false;
	178
	179	if (info->match_flags & XT_CONNTRACK_EXPIRES) {
	180	unsigned long expires = 0;
	181
	182	if (timer_pending(&ct->timeout))
	183	expires = (ct->timeout.expires - jiffies) / HZ;
	184	if ((expires >= info->expires_min &&
	185	expires <= info->expires_max) ^
	186	!(info->invert_flags & XT_CONNTRACK_EXPIRES))
	187	return false;
	188	}
	189	return true;
	190	}
	191
d6d3f08b JE	192	static bool
	193	conntrack_mt_v1(const struct sk_buff skb, const struct xt_match_param par)
	194	{
	195	const struct xt_conntrack_mtinfo2 const info = par->matchinfo;
	196	struct xt_match_param newpar = *par;
	197
	198	newpar.matchinfo = *info;
	199	return conntrack_mt(skb, &newpar);
	200	}
	201
9b4fce7a	202	static bool conntrack_mt_check(const struct xt_mtchk_param *par)
b9f78f9f	203	{
92f3b2b1	204	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
fe0b9294	205	printk(KERN_WARNING "can't load conntrack support for "
92f3b2b1	206	"proto=%u\n", par->family);
ccb79bdc	207	return false;
b9f78f9f	208	}
ccb79bdc	209	return true;
b9f78f9f PNA	210	}
b9f78f9f PNA	211
d6d3f08b JE	212	static bool conntrack_mt_check_v1(const struct xt_mtchk_param *par)
	213	{
	214	struct xt_conntrack_mtinfo1 *info = par->matchinfo;
	215	struct xt_conntrack_mtinfo2 *up;
	216	int ret = conntrack_mt_check(par);
	217
	218	if (ret < 0)
	219	return ret;
	220
	221	up = kmalloc(sizeof(*up), GFP_KERNEL);
	222	if (up == NULL) {
	223	nf_ct_l3proto_module_put(par->family);
	224	return -ENOMEM;
	225	}
	226
	227	/*
	228	* The strategy here is to minimize the overhead of v1 matching,
	229	* by prebuilding a v2 struct and putting the pointer into the
	230	* v1 dataspace.
	231	*/
	232	memcpy(up, info, offsetof(typeof(*info), state_mask));
	233	up->state_mask = info->state_mask;
	234	up->status_mask = info->status_mask;
	235	(void *)info = up;
	236	return true;
	237	}
	238
6be3d859	239	static void conntrack_mt_destroy(const struct xt_mtdtor_param *par)
b9f78f9f	240	{
92f3b2b1	241	nf_ct_l3proto_module_put(par->family);
b9f78f9f PNA	242	}
b9f78f9f PNA	243
d6d3f08b JE	244	static void conntrack_mt_destroy_v1(const struct xt_mtdtor_param *par)
	245	{
	246	struct xt_conntrack_mtinfo2 **info = par->matchinfo;
	247	kfree(*info);
	248	conntrack_mt_destroy(par);
	249	}
	250
64eb12f9	251	static struct xt_match conntrack_mt_reg[] __read_mostly = {
64eb12f9 JE	252	{
	253	.name = "conntrack",
	254	.revision = 1,
92f3b2b1	255	.family = NFPROTO_UNSPEC,
64eb12f9	256	.matchsize = sizeof(struct xt_conntrack_mtinfo1),
d6d3f08b JE	257	.match = conntrack_mt_v1,
	258	.checkentry = conntrack_mt_check_v1,
	259	.destroy = conntrack_mt_destroy_v1,
	260	.me = THIS_MODULE,
	261	},
	262	{
	263	.name = "conntrack",
	264	.revision = 2,
	265	.family = NFPROTO_UNSPEC,
	266	.matchsize = sizeof(struct xt_conntrack_mtinfo2),
64eb12f9 JE	267	.match = conntrack_mt,
	268	.checkentry = conntrack_mt_check,
	269	.destroy = conntrack_mt_destroy,
	270	.me = THIS_MODULE,
	271	},
1da177e4 LT	272	};
1da177e4 LT	273
d3c5ee6d	274	static int __init conntrack_mt_init(void)
1da177e4	275	{
64eb12f9 JE	276	return xt_register_matches(conntrack_mt_reg,
64eb12f9 JE	277	ARRAY_SIZE(conntrack_mt_reg));
1da177e4 LT	278	}
1da177e4 LT	279
d3c5ee6d	280	static void __exit conntrack_mt_exit(void)
1da177e4	281	{
64eb12f9	282	xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg));
1da177e4 LT	283	}
1da177e4 LT	284
d3c5ee6d JE	285	module_init(conntrack_mt_init);
d3c5ee6d JE	286	module_exit(conntrack_mt_exit);