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1 | /* | |
2 | * xt_connmark - Netfilter module to operate on connection marks | |
3 | * | |
4 | * Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com> | |
5 | * by Henrik Nordstrom <hno@marasystems.com> | |
6 | * Copyright © CC Computer Consultants GmbH, 2007 - 2008 | |
7 | * Jan Engelhardt <jengelh@medozas.de> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
21 | */ | |
22 | ||
23 | #include <linux/module.h> | |
24 | #include <linux/skbuff.h> | |
25 | #include <net/netfilter/nf_conntrack.h> | |
26 | #include <net/netfilter/nf_conntrack_ecache.h> | |
27 | #include <linux/netfilter/x_tables.h> | |
28 | #include <linux/netfilter/xt_connmark.h> | |
29 | ||
30 | MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>"); | |
31 | MODULE_DESCRIPTION("Xtables: connection mark operations"); | |
32 | MODULE_LICENSE("GPL"); | |
33 | MODULE_ALIAS("ipt_CONNMARK"); | |
34 | MODULE_ALIAS("ip6t_CONNMARK"); | |
35 | MODULE_ALIAS("ipt_connmark"); | |
36 | MODULE_ALIAS("ip6t_connmark"); | |
37 | ||
38 | static unsigned int | |
39 | connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) | |
40 | { | |
41 | const struct xt_connmark_tginfo1 *info = par->targinfo; | |
42 | enum ip_conntrack_info ctinfo; | |
43 | struct nf_conn *ct; | |
44 | u_int32_t newmark; | |
45 | ||
46 | ct = nf_ct_get(skb, &ctinfo); | |
47 | if (ct == NULL) | |
48 | return XT_CONTINUE; | |
49 | ||
50 | switch (info->mode) { | |
51 | case XT_CONNMARK_SET: | |
52 | newmark = (ct->mark & ~info->ctmask) ^ info->ctmark; | |
53 | if (ct->mark != newmark) { | |
54 | ct->mark = newmark; | |
55 | nf_conntrack_event_cache(IPCT_MARK, ct); | |
56 | } | |
57 | break; | |
58 | case XT_CONNMARK_SAVE: | |
59 | newmark = (ct->mark & ~info->ctmask) ^ | |
60 | (skb->mark & info->nfmask); | |
61 | if (ct->mark != newmark) { | |
62 | ct->mark = newmark; | |
63 | nf_conntrack_event_cache(IPCT_MARK, ct); | |
64 | } | |
65 | break; | |
66 | case XT_CONNMARK_RESTORE: | |
67 | newmark = (skb->mark & ~info->nfmask) ^ | |
68 | (ct->mark & info->ctmask); | |
69 | skb->mark = newmark; | |
70 | break; | |
71 | } | |
72 | ||
73 | return XT_CONTINUE; | |
74 | } | |
75 | ||
76 | static int connmark_tg_check(const struct xt_tgchk_param *par) | |
77 | { | |
78 | int ret; | |
79 | ||
80 | ret = nf_ct_l3proto_try_module_get(par->family); | |
81 | if (ret < 0) | |
82 | pr_info("cannot load conntrack support for proto=%u\n", | |
83 | par->family); | |
84 | return ret; | |
85 | } | |
86 | ||
87 | static void connmark_tg_destroy(const struct xt_tgdtor_param *par) | |
88 | { | |
89 | nf_ct_l3proto_module_put(par->family); | |
90 | } | |
91 | ||
92 | static bool | |
93 | connmark_mt(const struct sk_buff *skb, struct xt_action_param *par) | |
94 | { | |
95 | const struct xt_connmark_mtinfo1 *info = par->matchinfo; | |
96 | enum ip_conntrack_info ctinfo; | |
97 | const struct nf_conn *ct; | |
98 | ||
99 | ct = nf_ct_get(skb, &ctinfo); | |
100 | if (ct == NULL) | |
101 | return false; | |
102 | ||
103 | return ((ct->mark & info->mask) == info->mark) ^ info->invert; | |
104 | } | |
105 | ||
106 | static int connmark_mt_check(const struct xt_mtchk_param *par) | |
107 | { | |
108 | int ret; | |
109 | ||
110 | ret = nf_ct_l3proto_try_module_get(par->family); | |
111 | if (ret < 0) | |
112 | pr_info("cannot load conntrack support for proto=%u\n", | |
113 | par->family); | |
114 | return ret; | |
115 | } | |
116 | ||
117 | static void connmark_mt_destroy(const struct xt_mtdtor_param *par) | |
118 | { | |
119 | nf_ct_l3proto_module_put(par->family); | |
120 | } | |
121 | ||
122 | static struct xt_target connmark_tg_reg __read_mostly = { | |
123 | .name = "CONNMARK", | |
124 | .revision = 1, | |
125 | .family = NFPROTO_UNSPEC, | |
126 | .checkentry = connmark_tg_check, | |
127 | .target = connmark_tg, | |
128 | .targetsize = sizeof(struct xt_connmark_tginfo1), | |
129 | .destroy = connmark_tg_destroy, | |
130 | .me = THIS_MODULE, | |
131 | }; | |
132 | ||
133 | static struct xt_match connmark_mt_reg __read_mostly = { | |
134 | .name = "connmark", | |
135 | .revision = 1, | |
136 | .family = NFPROTO_UNSPEC, | |
137 | .checkentry = connmark_mt_check, | |
138 | .match = connmark_mt, | |
139 | .matchsize = sizeof(struct xt_connmark_mtinfo1), | |
140 | .destroy = connmark_mt_destroy, | |
141 | .me = THIS_MODULE, | |
142 | }; | |
143 | ||
144 | static int __init connmark_mt_init(void) | |
145 | { | |
146 | int ret; | |
147 | ||
148 | ret = xt_register_target(&connmark_tg_reg); | |
149 | if (ret < 0) | |
150 | return ret; | |
151 | ret = xt_register_match(&connmark_mt_reg); | |
152 | if (ret < 0) { | |
153 | xt_unregister_target(&connmark_tg_reg); | |
154 | return ret; | |
155 | } | |
156 | return 0; | |
157 | } | |
158 | ||
159 | static void __exit connmark_mt_exit(void) | |
160 | { | |
161 | xt_unregister_match(&connmark_mt_reg); | |
162 | xt_unregister_target(&connmark_tg_reg); | |
163 | } | |
164 | ||
165 | module_init(connmark_mt_init); | |
166 | module_exit(connmark_mt_exit); |