Commit | Line | Data |
---|---|---|
f3389805 PM |
1 | /* |
2 | * Copyright (c) 2006 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 | * Based on ipt_random and ipt_nth by Fabrice MARIE <fabrice@netfilter.org>. | |
9 | */ | |
10 | ||
11 | #include <linux/init.h> | |
12 | #include <linux/spinlock.h> | |
13 | #include <linux/skbuff.h> | |
14 | #include <linux/net.h> | |
15 | ||
16 | #include <linux/netfilter/xt_statistic.h> | |
17 | #include <linux/netfilter/x_tables.h> | |
18 | ||
19 | MODULE_LICENSE("GPL"); | |
20 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
2ae15b64 | 21 | MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)"); |
f3389805 PM |
22 | MODULE_ALIAS("ipt_statistic"); |
23 | MODULE_ALIAS("ip6t_statistic"); | |
24 | ||
25 | static DEFINE_SPINLOCK(nth_lock); | |
26 | ||
1d93a9cb | 27 | static bool |
d3c5ee6d JE |
28 | statistic_mt(const struct sk_buff *skb, const struct net_device *in, |
29 | const struct net_device *out, const struct xt_match *match, | |
30 | const void *matchinfo, int offset, unsigned int protoff, | |
31 | bool *hotdrop) | |
f3389805 PM |
32 | { |
33 | struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo; | |
1d93a9cb | 34 | bool ret = info->flags & XT_STATISTIC_INVERT; |
f3389805 PM |
35 | |
36 | switch (info->mode) { | |
37 | case XT_STATISTIC_MODE_RANDOM: | |
38 | if ((net_random() & 0x7FFFFFFF) < info->u.random.probability) | |
1d93a9cb | 39 | ret = !ret; |
f3389805 PM |
40 | break; |
41 | case XT_STATISTIC_MODE_NTH: | |
42 | info = info->master; | |
43 | spin_lock_bh(&nth_lock); | |
44 | if (info->u.nth.count++ == info->u.nth.every) { | |
45 | info->u.nth.count = 0; | |
1d93a9cb | 46 | ret = !ret; |
f3389805 PM |
47 | } |
48 | spin_unlock_bh(&nth_lock); | |
49 | break; | |
50 | } | |
51 | ||
52 | return ret; | |
53 | } | |
54 | ||
ccb79bdc | 55 | static bool |
d3c5ee6d JE |
56 | statistic_mt_check(const char *tablename, const void *entry, |
57 | const struct xt_match *match, void *matchinfo, | |
58 | unsigned int hook_mask) | |
f3389805 | 59 | { |
a47362a2 | 60 | struct xt_statistic_info *info = matchinfo; |
f3389805 PM |
61 | |
62 | if (info->mode > XT_STATISTIC_MODE_MAX || | |
63 | info->flags & ~XT_STATISTIC_MASK) | |
ccb79bdc | 64 | return false; |
f3389805 | 65 | info->master = info; |
ccb79bdc | 66 | return true; |
f3389805 PM |
67 | } |
68 | ||
d3c5ee6d | 69 | static struct xt_match statistic_mt_reg[] __read_mostly = { |
4470bbc7 PM |
70 | { |
71 | .name = "statistic", | |
72 | .family = AF_INET, | |
d3c5ee6d JE |
73 | .checkentry = statistic_mt_check, |
74 | .match = statistic_mt, | |
4470bbc7 PM |
75 | .matchsize = sizeof(struct xt_statistic_info), |
76 | .me = THIS_MODULE, | |
77 | }, | |
78 | { | |
79 | .name = "statistic", | |
80 | .family = AF_INET6, | |
d3c5ee6d JE |
81 | .checkentry = statistic_mt_check, |
82 | .match = statistic_mt, | |
4470bbc7 PM |
83 | .matchsize = sizeof(struct xt_statistic_info), |
84 | .me = THIS_MODULE, | |
85 | }, | |
f3389805 PM |
86 | }; |
87 | ||
d3c5ee6d | 88 | static int __init statistic_mt_init(void) |
f3389805 | 89 | { |
d3c5ee6d JE |
90 | return xt_register_matches(statistic_mt_reg, |
91 | ARRAY_SIZE(statistic_mt_reg)); | |
f3389805 PM |
92 | } |
93 | ||
d3c5ee6d | 94 | static void __exit statistic_mt_exit(void) |
f3389805 | 95 | { |
d3c5ee6d JE |
96 | xt_unregister_matches(statistic_mt_reg, |
97 | ARRAY_SIZE(statistic_mt_reg)); | |
f3389805 PM |
98 | } |
99 | ||
d3c5ee6d JE |
100 | module_init(statistic_mt_init); |
101 | module_exit(statistic_mt_exit); |