1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * (C) 2013 Astaro GmbH & Co KG
4 */
5
6#include <linux/module.h>
7#include <linux/skbuff.h>
8#include <net/netfilter/nf_conntrack.h>
9#include <net/netfilter/nf_conntrack_ecache.h>
10#include <net/netfilter/nf_conntrack_labels.h>
11#include <linux/netfilter/x_tables.h>
12
13MODULE_LICENSE("GPL");
14MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
15MODULE_DESCRIPTION("Xtables: add/match connection tracking labels");
16MODULE_ALIAS("ipt_connlabel");
17MODULE_ALIAS("ip6t_connlabel");
18
19static bool
20connlabel_mt(const struct sk_buff *skb, struct xt_action_param *par)
21{
22	const struct xt_connlabel_mtinfo *info = par->matchinfo;
23	enum ip_conntrack_info ctinfo;
24	struct nf_conn_labels *labels;
25	struct nf_conn *ct;
26	bool invert = info->options & XT_CONNLABEL_OP_INVERT;
27
28	ct = nf_ct_get(skb, &ctinfo);
29	if (ct == NULL)
30		return invert;
31
32	labels = nf_ct_labels_find(ct);
33	if (!labels)
34		return invert;
35
36	if (test_bit(info->bit, labels->bits))
37		return !invert;
38
39	if (info->options & XT_CONNLABEL_OP_SET) {
40		if (!test_and_set_bit(info->bit, labels->bits))
41			nf_conntrack_event_cache(IPCT_LABEL, ct);
42
43		return !invert;
44	}
45
46	return invert;
47}
48
49static int connlabel_mt_check(const struct xt_mtchk_param *par)
50{
51	const int options = XT_CONNLABEL_OP_INVERT |
52			    XT_CONNLABEL_OP_SET;
53	struct xt_connlabel_mtinfo *info = par->matchinfo;
54	int ret;
55
56	if (info->options & ~options) {
57		pr_info_ratelimited("Unknown options in mask %x\n",
58				    info->options);
59		return -EINVAL;
60	}
61
62	ret = nf_ct_netns_get(par->net, par->family);
63	if (ret < 0) {
64		pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
65				    par->family);
66		return ret;
67	}
68
69	ret = nf_connlabels_get(par->net, info->bit);
70	if (ret < 0)
71		nf_ct_netns_put(par->net, par->family);
72	return ret;
73}
74
75static void connlabel_mt_destroy(const struct xt_mtdtor_param *par)
76{
77	nf_connlabels_put(par->net);
78	nf_ct_netns_put(par->net, par->family);
79}
80
81static struct xt_match connlabels_mt_reg __read_mostly = {
82	.name           = "connlabel",
83	.family         = NFPROTO_UNSPEC,
84	.checkentry     = connlabel_mt_check,
85	.match          = connlabel_mt,
86	.matchsize      = sizeof(struct xt_connlabel_mtinfo),
87	.destroy        = connlabel_mt_destroy,
88	.me             = THIS_MODULE,
89};
90
91static int __init connlabel_mt_init(void)
92{
93	return xt_register_match(&connlabels_mt_reg);
94}
95
96static void __exit connlabel_mt_exit(void)
97{
98	xt_unregister_match(&connlabels_mt_reg);
99}
100
101module_init(connlabel_mt_init);
102module_exit(connlabel_mt_exit);
103