[net-next-2.6.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.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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, struct xt_action_param *par,
             u16 state_mask, u16 status_mask)
{
	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) {
		if (nf_ct_is_untracked(ct))
			statebit = XT_CONNTRACK_STATE_UNTRACKED;
		else
			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 (!!(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) &&
	    (!!(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, struct xt_action_param *par)
{
	const struct xt_conntrack_mtinfo1 *info = par->matchinfo;

	return conntrack_mt(skb, par, info->state_mask, info->status_mask);
}

static bool
conntrack_mt_v2(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_conntrack_mtinfo2 *info = par->matchinfo;

	return conntrack_mt(skb, par, info->state_mask, info->status_mask);
}

static int conntrack_mt_check(const struct xt_mtchk_param *par)
{
	int ret;

	ret = nf_ct_l3proto_try_module_get(par->family);
	if (ret < 0)
		pr_info("cannot load conntrack support for proto=%u\n",
			par->family);
	return ret;
}

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

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,
		.destroy    = conntrack_mt_destroy,
		.me         = THIS_MODULE,
	},
	{
		.name       = "conntrack",
		.revision   = 2,
		.family     = NFPROTO_UNSPEC,
		.matchsize  = sizeof(struct xt_conntrack_mtinfo2),
		.match      = conntrack_mt_v2,
		.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	11	*/
8bee4bad	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
1da177e4 LT	13	#include <linux/module.h>
1da177e4 LT	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
62fc8051	116	conntrack_mt(const struct sk_buff skb, struct xt_action_param par,
3a042929	117	u16 state_mask, u16 status_mask)
64eb12f9	118	{
d6d3f08b	119	const struct xt_conntrack_mtinfo2 *info = par->matchinfo;
64eb12f9 JE	120	enum ip_conntrack_info ctinfo;
	121	const struct nf_conn *ct;
	122	unsigned int statebit;
	123
	124	ct = nf_ct_get(skb, &ctinfo);
	125
5bfddbd4 ED	126	if (ct) {
	127	if (nf_ct_is_untracked(ct))
	128	statebit = XT_CONNTRACK_STATE_UNTRACKED;
	129	else
	130	statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
	131	} else
64eb12f9 JE	132	statebit = XT_CONNTRACK_STATE_INVALID;
	133
	134	if (info->match_flags & XT_CONNTRACK_STATE) {
	135	if (ct != NULL) {
	136	if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
	137	statebit \|= XT_CONNTRACK_STATE_SNAT;
	138	if (test_bit(IPS_DST_NAT_BIT, &ct->status))
	139	statebit \|= XT_CONNTRACK_STATE_DNAT;
	140	}
3a042929	141	if (!!(state_mask & statebit) ^
64eb12f9 JE	142	!(info->invert_flags & XT_CONNTRACK_STATE))
	143	return false;
	144	}
	145
	146	if (ct == NULL)
	147	return info->match_flags & XT_CONNTRACK_STATE;
b4164998 JE	148	if ((info->match_flags & XT_CONNTRACK_DIRECTION) &&
	149	(CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^
	150	!!(info->invert_flags & XT_CONNTRACK_DIRECTION))
64eb12f9 JE	151	return false;
	152
	153	if (info->match_flags & XT_CONNTRACK_ORIGSRC)
92f3b2b1	154	if (conntrack_mt_origsrc(ct, info, par->family) ^
64eb12f9 JE	155	!(info->invert_flags & XT_CONNTRACK_ORIGSRC))
	156	return false;
	157
	158	if (info->match_flags & XT_CONNTRACK_ORIGDST)
92f3b2b1	159	if (conntrack_mt_origdst(ct, info, par->family) ^
64eb12f9 JE	160	!(info->invert_flags & XT_CONNTRACK_ORIGDST))
	161	return false;
	162
	163	if (info->match_flags & XT_CONNTRACK_REPLSRC)
92f3b2b1	164	if (conntrack_mt_replsrc(ct, info, par->family) ^
64eb12f9 JE	165	!(info->invert_flags & XT_CONNTRACK_REPLSRC))
	166	return false;
	167
	168	if (info->match_flags & XT_CONNTRACK_REPLDST)
92f3b2b1	169	if (conntrack_mt_repldst(ct, info, par->family) ^
64eb12f9 JE	170	!(info->invert_flags & XT_CONNTRACK_REPLDST))
	171	return false;
	172
b4164998 JE	173	if (!ct_proto_port_check(info, ct))
	174	return false;
	175
64eb12f9	176	if ((info->match_flags & XT_CONNTRACK_STATUS) &&
3a042929	177	(!!(status_mask & ct->status) ^
64eb12f9 JE	178	!(info->invert_flags & XT_CONNTRACK_STATUS)))
	179	return false;
	180
	181	if (info->match_flags & XT_CONNTRACK_EXPIRES) {
	182	unsigned long expires = 0;
	183
	184	if (timer_pending(&ct->timeout))
	185	expires = (ct->timeout.expires - jiffies) / HZ;
	186	if ((expires >= info->expires_min &&
	187	expires <= info->expires_max) ^
	188	!(info->invert_flags & XT_CONNTRACK_EXPIRES))
	189	return false;
	190	}
	191	return true;
	192	}
	193
d6d3f08b	194	static bool
62fc8051	195	conntrack_mt_v1(const struct sk_buff skb, struct xt_action_param par)
d6d3f08b	196	{
3a042929	197	const struct xt_conntrack_mtinfo1 *info = par->matchinfo;
d6d3f08b	198
3a042929 FW	199	return conntrack_mt(skb, par, info->state_mask, info->status_mask);
	200	}
	201
	202	static bool
62fc8051	203	conntrack_mt_v2(const struct sk_buff skb, struct xt_action_param par)
3a042929 FW	204	{
	205	const struct xt_conntrack_mtinfo2 *info = par->matchinfo;
	206
	207	return conntrack_mt(skb, par, info->state_mask, info->status_mask);
d6d3f08b JE	208	}
d6d3f08b JE	209
b0f38452	210	static int conntrack_mt_check(const struct xt_mtchk_param *par)
b9f78f9f	211	{
4a5a5c73 JE	212	int ret;
	213
	214	ret = nf_ct_l3proto_try_module_get(par->family);
f95c74e3	215	if (ret < 0)
8bee4bad JE	216	pr_info("cannot load conntrack support for proto=%u\n",
8bee4bad JE	217	par->family);
f95c74e3	218	return ret;
b9f78f9f PNA	219	}
b9f78f9f PNA	220
6be3d859	221	static void conntrack_mt_destroy(const struct xt_mtdtor_param *par)
b9f78f9f	222	{
92f3b2b1	223	nf_ct_l3proto_module_put(par->family);
b9f78f9f PNA	224	}
b9f78f9f PNA	225
64eb12f9	226	static struct xt_match conntrack_mt_reg[] __read_mostly = {
64eb12f9 JE	227	{
	228	.name = "conntrack",
	229	.revision = 1,
92f3b2b1	230	.family = NFPROTO_UNSPEC,
64eb12f9	231	.matchsize = sizeof(struct xt_conntrack_mtinfo1),
d6d3f08b	232	.match = conntrack_mt_v1,
3a042929 FW	233	.checkentry = conntrack_mt_check,
3a042929 FW	234	.destroy = conntrack_mt_destroy,
d6d3f08b JE	235	.me = THIS_MODULE,
	236	},
	237	{
	238	.name = "conntrack",
	239	.revision = 2,
	240	.family = NFPROTO_UNSPEC,
	241	.matchsize = sizeof(struct xt_conntrack_mtinfo2),
3a042929	242	.match = conntrack_mt_v2,
64eb12f9 JE	243	.checkentry = conntrack_mt_check,
	244	.destroy = conntrack_mt_destroy,
	245	.me = THIS_MODULE,
	246	},
1da177e4 LT	247	};
1da177e4 LT	248
d3c5ee6d	249	static int __init conntrack_mt_init(void)
1da177e4	250	{
64eb12f9 JE	251	return xt_register_matches(conntrack_mt_reg,
64eb12f9 JE	252	ARRAY_SIZE(conntrack_mt_reg));
1da177e4 LT	253	}
1da177e4 LT	254
d3c5ee6d	255	static void __exit conntrack_mt_exit(void)
1da177e4	256	{
64eb12f9	257	xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg));
1da177e4 LT	258	}
1da177e4 LT	259
d3c5ee6d JE	260	module_init(conntrack_mt_init);
d3c5ee6d JE	261	module_exit(conntrack_mt_exit);