1 /*
2 * (C) 2013 Astaro GmbH & Co KG
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9 #include <linux/module.h>
10 #include <linux/skbuff.h>
11 #include <net/netfilter/nf_conntrack.h>
12 #include <net/netfilter/nf_conntrack_ecache.h>
13 #include <net/netfilter/nf_conntrack_labels.h>
14 #include <linux/netfilter/x_tables.h>
15
16 MODULE_LICENSE("GPL");
17 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
18 MODULE_DESCRIPTION("Xtables: add/match connection trackling labels");
19 MODULE_ALIAS("ipt_connlabel");
20 MODULE_ALIAS("ip6t_connlabel");
21
22 static bool
connlabel_mt(const struct sk_buff * skb,struct xt_action_param * par)23 connlabel_mt(const struct sk_buff *skb, struct xt_action_param *par)
24 {
25 const struct xt_connlabel_mtinfo *info = par->matchinfo;
26 enum ip_conntrack_info ctinfo;
27 struct nf_conn_labels *labels;
28 struct nf_conn *ct;
29 bool invert = info->options & XT_CONNLABEL_OP_INVERT;
30
31 ct = nf_ct_get(skb, &ctinfo);
32 if (ct == NULL || nf_ct_is_untracked(ct))
33 return invert;
34
35 labels = nf_ct_labels_find(ct);
36 if (!labels)
37 return invert;
38
39 if (test_bit(info->bit, labels->bits))
40 return !invert;
41
42 if (info->options & XT_CONNLABEL_OP_SET) {
43 if (!test_and_set_bit(info->bit, labels->bits))
44 nf_conntrack_event_cache(IPCT_LABEL, ct);
45
46 return !invert;
47 }
48
49 return invert;
50 }
51
connlabel_mt_check(const struct xt_mtchk_param * par)52 static int connlabel_mt_check(const struct xt_mtchk_param *par)
53 {
54 const int options = XT_CONNLABEL_OP_INVERT |
55 XT_CONNLABEL_OP_SET;
56 struct xt_connlabel_mtinfo *info = par->matchinfo;
57 int ret;
58
59 if (info->options & ~options) {
60 pr_err("Unknown options in mask %x\n", info->options);
61 return -EINVAL;
62 }
63
64 ret = nf_ct_l3proto_try_module_get(par->family);
65 if (ret < 0) {
66 pr_info("cannot load conntrack support for proto=%u\n",
67 par->family);
68 return ret;
69 }
70
71 ret = nf_connlabels_get(par->net, info->bit);
72 if (ret < 0)
73 nf_ct_l3proto_module_put(par->family);
74 return ret;
75 }
76
connlabel_mt_destroy(const struct xt_mtdtor_param * par)77 static void connlabel_mt_destroy(const struct xt_mtdtor_param *par)
78 {
79 nf_connlabels_put(par->net);
80 nf_ct_l3proto_module_put(par->family);
81 }
82
83 static struct xt_match connlabels_mt_reg __read_mostly = {
84 .name = "connlabel",
85 .family = NFPROTO_UNSPEC,
86 .checkentry = connlabel_mt_check,
87 .match = connlabel_mt,
88 .matchsize = sizeof(struct xt_connlabel_mtinfo),
89 .destroy = connlabel_mt_destroy,
90 .me = THIS_MODULE,
91 };
92
connlabel_mt_init(void)93 static int __init connlabel_mt_init(void)
94 {
95 return xt_register_match(&connlabels_mt_reg);
96 }
97
connlabel_mt_exit(void)98 static void __exit connlabel_mt_exit(void)
99 {
100 xt_unregister_match(&connlabels_mt_reg);
101 }
102
103 module_init(connlabel_mt_init);
104 module_exit(connlabel_mt_exit);
105