1// SPDX-License-Identifier: GPL-2.0-only
 2/* Kernel module to match connection tracking information. */
 3
 4/* (C) 1999-2001 Paul `Rusty' Russell
 5 * (C) 2002-2005 Netfilter Core Team <coreteam@netfilter.org>
 
 
 
 
 6 */
 7
 8#include <linux/module.h>
 9#include <linux/skbuff.h>
10#include <net/netfilter/nf_conntrack.h>
11#include <linux/netfilter/x_tables.h>
12#include <linux/netfilter/xt_state.h>
13
14MODULE_LICENSE("GPL");
15MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
16MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module");
17MODULE_ALIAS("ipt_state");
18MODULE_ALIAS("ip6t_state");
19
20static bool
21state_mt(const struct sk_buff *skb, struct xt_action_param *par)
22{
23	const struct xt_state_info *sinfo = par->matchinfo;
24	enum ip_conntrack_info ctinfo;
25	unsigned int statebit;
26	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
27
28	if (ct)
29		statebit = XT_STATE_BIT(ctinfo);
30	else if (ctinfo == IP_CT_UNTRACKED)
31		statebit = XT_STATE_UNTRACKED;
32	else
33		statebit = XT_STATE_INVALID;
34
 
 
 
 
 
35	return (sinfo->statemask & statebit);
36}
37
38static int state_mt_check(const struct xt_mtchk_param *par)
39{
40	int ret;
41
42	ret = nf_ct_netns_get(par->net, par->family);
43	if (ret < 0)
44		pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
45				    par->family);
46	return ret;
47}
48
49static void state_mt_destroy(const struct xt_mtdtor_param *par)
50{
51	nf_ct_netns_put(par->net, par->family);
52}
53
54static struct xt_match state_mt_reg __read_mostly = {
55	.name       = "state",
56	.family     = NFPROTO_UNSPEC,
57	.checkentry = state_mt_check,
58	.match      = state_mt,
59	.destroy    = state_mt_destroy,
60	.matchsize  = sizeof(struct xt_state_info),
61	.me         = THIS_MODULE,
62};
63
64static int __init state_mt_init(void)
65{
66	return xt_register_match(&state_mt_reg);
67}
68
69static void __exit state_mt_exit(void)
70{
71	xt_unregister_match(&state_mt_reg);
72}
73
74module_init(state_mt_init);
75module_exit(state_mt_exit);

 
 1/* Kernel module to match connection tracking information. */
 2
 3/* (C) 1999-2001 Paul `Rusty' Russell
 4 * (C) 2002-2005 Netfilter Core Team <coreteam@netfilter.org>
 5 *
 6 * This program is free software; you can redistribute it and/or modify
 7 * it under the terms of the GNU General Public License version 2 as
 8 * published by the Free Software Foundation.
 9 */
10
11#include <linux/module.h>
12#include <linux/skbuff.h>
13#include <net/netfilter/nf_conntrack.h>
14#include <linux/netfilter/x_tables.h>
15#include <linux/netfilter/xt_state.h>
16
17MODULE_LICENSE("GPL");
18MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
19MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module");
20MODULE_ALIAS("ipt_state");
21MODULE_ALIAS("ip6t_state");
22
23static bool
24state_mt(const struct sk_buff *skb, struct xt_action_param *par)
25{
26	const struct xt_state_info *sinfo = par->matchinfo;
27	enum ip_conntrack_info ctinfo;
28	unsigned int statebit;
29	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
30
31	if (!ct)
 
 
 
 
32		statebit = XT_STATE_INVALID;
33	else {
34		if (nf_ct_is_untracked(ct))
35			statebit = XT_STATE_UNTRACKED;
36		else
37			statebit = XT_STATE_BIT(ctinfo);
38	}
39	return (sinfo->statemask & statebit);
40}
41
42static int state_mt_check(const struct xt_mtchk_param *par)
43{
44	int ret;
45
46	ret = nf_ct_l3proto_try_module_get(par->family);
47	if (ret < 0)
48		pr_info("cannot load conntrack support for proto=%u\n",
49			par->family);
50	return ret;
51}
52
53static void state_mt_destroy(const struct xt_mtdtor_param *par)
54{
55	nf_ct_l3proto_module_put(par->family);
56}
57
58static struct xt_match state_mt_reg __read_mostly = {
59	.name       = "state",
60	.family     = NFPROTO_UNSPEC,
61	.checkentry = state_mt_check,
62	.match      = state_mt,
63	.destroy    = state_mt_destroy,
64	.matchsize  = sizeof(struct xt_state_info),
65	.me         = THIS_MODULE,
66};
67
68static int __init state_mt_init(void)
69{
70	return xt_register_match(&state_mt_reg);
71}
72
73static void __exit state_mt_exit(void)
74{
75	xt_unregister_match(&state_mt_reg);
76}
77
78module_init(state_mt_init);
79module_exit(state_mt_exit);