xref: /openbmc/linux/net/netfilter/xt_devgroup.c (revision e5c86679)
1 /*
2  * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
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 <linux/netdevice.h>
12 
13 #include <linux/netfilter/xt_devgroup.h>
14 #include <linux/netfilter/x_tables.h>
15 
16 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
17 MODULE_LICENSE("GPL");
18 MODULE_DESCRIPTION("Xtables: Device group match");
19 MODULE_ALIAS("ipt_devgroup");
20 MODULE_ALIAS("ip6t_devgroup");
21 
22 static bool devgroup_mt(const struct sk_buff *skb, struct xt_action_param *par)
23 {
24 	const struct xt_devgroup_info *info = par->matchinfo;
25 
26 	if (info->flags & XT_DEVGROUP_MATCH_SRC &&
27 	    (((info->src_group ^ xt_in(par)->group) & info->src_mask ? 1 : 0) ^
28 	     ((info->flags & XT_DEVGROUP_INVERT_SRC) ? 1 : 0)))
29 		return false;
30 
31 	if (info->flags & XT_DEVGROUP_MATCH_DST &&
32 	    (((info->dst_group ^ xt_out(par)->group) & info->dst_mask ? 1 : 0) ^
33 	     ((info->flags & XT_DEVGROUP_INVERT_DST) ? 1 : 0)))
34 		return false;
35 
36 	return true;
37 }
38 
39 static int devgroup_mt_checkentry(const struct xt_mtchk_param *par)
40 {
41 	const struct xt_devgroup_info *info = par->matchinfo;
42 
43 	if (info->flags & ~(XT_DEVGROUP_MATCH_SRC | XT_DEVGROUP_INVERT_SRC |
44 			    XT_DEVGROUP_MATCH_DST | XT_DEVGROUP_INVERT_DST))
45 		return -EINVAL;
46 
47 	if (info->flags & XT_DEVGROUP_MATCH_SRC &&
48 	    par->hook_mask & ~((1 << NF_INET_PRE_ROUTING) |
49 			       (1 << NF_INET_LOCAL_IN) |
50 			       (1 << NF_INET_FORWARD)))
51 		return -EINVAL;
52 
53 	if (info->flags & XT_DEVGROUP_MATCH_DST &&
54 	    par->hook_mask & ~((1 << NF_INET_FORWARD) |
55 			       (1 << NF_INET_LOCAL_OUT) |
56 			       (1 << NF_INET_POST_ROUTING)))
57 		return -EINVAL;
58 
59 	return 0;
60 }
61 
62 static struct xt_match devgroup_mt_reg __read_mostly = {
63 	.name		= "devgroup",
64 	.match		= devgroup_mt,
65 	.checkentry	= devgroup_mt_checkentry,
66 	.matchsize	= sizeof(struct xt_devgroup_info),
67 	.family		= NFPROTO_UNSPEC,
68 	.me		= THIS_MODULE
69 };
70 
71 static int __init devgroup_mt_init(void)
72 {
73 	return xt_register_match(&devgroup_mt_reg);
74 }
75 
76 static void __exit devgroup_mt_exit(void)
77 {
78 	xt_unregister_match(&devgroup_mt_reg);
79 }
80 
81 module_init(devgroup_mt_init);
82 module_exit(devgroup_mt_exit);
83