Commit | Line | Data |
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c539f017 FW |
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_labels.h> | |
13 | #include <linux/netfilter/x_tables.h> | |
14 | ||
15 | MODULE_LICENSE("GPL"); | |
16 | MODULE_AUTHOR("Florian Westphal <fw@strlen.de>"); | |
17 | MODULE_DESCRIPTION("Xtables: add/match connection trackling labels"); | |
18 | MODULE_ALIAS("ipt_connlabel"); | |
19 | MODULE_ALIAS("ip6t_connlabel"); | |
20 | ||
21 | static bool | |
22 | connlabel_mt(const struct sk_buff *skb, struct xt_action_param *par) | |
23 | { | |
24 | const struct xt_connlabel_mtinfo *info = par->matchinfo; | |
25 | enum ip_conntrack_info ctinfo; | |
26 | struct nf_conn *ct; | |
27 | bool invert = info->options & XT_CONNLABEL_OP_INVERT; | |
28 | ||
29 | ct = nf_ct_get(skb, &ctinfo); | |
30 | if (ct == NULL || nf_ct_is_untracked(ct)) | |
31 | return invert; | |
32 | ||
33 | if (info->options & XT_CONNLABEL_OP_SET) | |
34 | return (nf_connlabel_set(ct, info->bit) == 0) ^ invert; | |
35 | ||
36 | return nf_connlabel_match(ct, info->bit) ^ invert; | |
37 | } | |
38 | ||
39 | static int connlabel_mt_check(const struct xt_mtchk_param *par) | |
40 | { | |
41 | const int options = XT_CONNLABEL_OP_INVERT | | |
42 | XT_CONNLABEL_OP_SET; | |
43 | struct xt_connlabel_mtinfo *info = par->matchinfo; | |
44 | int ret; | |
45 | size_t words; | |
46 | ||
47 | if (info->bit > XT_CONNLABEL_MAXBIT) | |
48 | return -ERANGE; | |
49 | ||
50 | if (info->options & ~options) { | |
51 | pr_err("Unknown options in mask %x\n", info->options); | |
52 | return -EINVAL; | |
53 | } | |
54 | ||
55 | ret = nf_ct_l3proto_try_module_get(par->family); | |
56 | if (ret < 0) { | |
57 | pr_info("cannot load conntrack support for proto=%u\n", | |
58 | par->family); | |
59 | return ret; | |
60 | } | |
61 | ||
62 | par->net->ct.labels_used++; | |
63 | words = BITS_TO_LONGS(info->bit+1); | |
64 | if (words > par->net->ct.label_words) | |
65 | par->net->ct.label_words = words; | |
66 | ||
67 | return ret; | |
68 | } | |
69 | ||
70 | static void connlabel_mt_destroy(const struct xt_mtdtor_param *par) | |
71 | { | |
72 | par->net->ct.labels_used--; | |
73 | if (par->net->ct.labels_used == 0) | |
74 | par->net->ct.label_words = 0; | |
75 | nf_ct_l3proto_module_put(par->family); | |
76 | } | |
77 | ||
78 | static struct xt_match connlabels_mt_reg __read_mostly = { | |
79 | .name = "connlabel", | |
80 | .family = NFPROTO_UNSPEC, | |
81 | .checkentry = connlabel_mt_check, | |
82 | .match = connlabel_mt, | |
83 | .matchsize = sizeof(struct xt_connlabel_mtinfo), | |
84 | .destroy = connlabel_mt_destroy, | |
85 | .me = THIS_MODULE, | |
86 | }; | |
87 | ||
88 | static int __init connlabel_mt_init(void) | |
89 | { | |
90 | return xt_register_match(&connlabels_mt_reg); | |
91 | } | |
92 | ||
93 | static void __exit connlabel_mt_exit(void) | |
94 | { | |
95 | xt_unregister_match(&connlabels_mt_reg); | |
96 | } | |
97 | ||
98 | module_init(connlabel_mt_init); | |
99 | module_exit(connlabel_mt_exit); |