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
13 MODULE_LICENSE("GPL");
14 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
15 MODULE_DESCRIPTION("Xtables: add/match connection tracking labels");
16 MODULE_ALIAS("ipt_connlabel");
17 MODULE_ALIAS("ip6t_connlabel");
18
19 static bool
20 connlabel_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
49 static 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
75 static 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
81 static 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
91 static int __init connlabel_mt_init(void)
92 {
93 return xt_register_match(&connlabels_mt_reg);
94 }
95
96 static void __exit connlabel_mt_exit(void)
97 {
98 xt_unregister_match(&connlabels_mt_reg);
99 }
100
101 module_init(connlabel_mt_init);
102 module_exit(connlabel_mt_exit);
103
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