[PATCH] w1: Userspace communication protocol over connector.
[linux-2.6/verdex.git] / net / netfilter / xt_statistic.c
blobde1037f58596d3268e9ec4c7387b4787938d6b27
1 /*
2 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
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.
8 * Based on ipt_random and ipt_nth by Fabrice MARIE <fabrice@netfilter.org>.
9 */
11 #include <linux/init.h>
12 #include <linux/spinlock.h>
13 #include <linux/skbuff.h>
14 #include <linux/net.h>
16 #include <linux/netfilter/xt_statistic.h>
17 #include <linux/netfilter/x_tables.h>
19 MODULE_LICENSE("GPL");
20 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
21 MODULE_DESCRIPTION("xtables statistical match module");
22 MODULE_ALIAS("ipt_statistic");
23 MODULE_ALIAS("ip6t_statistic");
25 static DEFINE_SPINLOCK(nth_lock);
27 static int
28 match(const struct sk_buff *skb,
29 const struct net_device *in, const struct net_device *out,
30 const struct xt_match *match, const void *matchinfo,
31 int offset, unsigned int protoff, int *hotdrop)
33 struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
34 int ret = info->flags & XT_STATISTIC_INVERT ? 1 : 0;
36 switch (info->mode) {
37 case XT_STATISTIC_MODE_RANDOM:
38 if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
39 ret ^= 1;
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;
46 ret ^= 1;
48 spin_unlock_bh(&nth_lock);
49 break;
52 return ret;
55 static int
56 checkentry(const char *tablename, const void *entry,
57 const struct xt_match *match, void *matchinfo,
58 unsigned int matchsize, unsigned int hook_mask)
60 struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
62 if (info->mode > XT_STATISTIC_MODE_MAX ||
63 info->flags & ~XT_STATISTIC_MASK)
64 return 0;
65 info->master = info;
66 return 1;
69 static struct xt_match statistic_match = {
70 .name = "statistic",
71 .match = match,
72 .matchsize = sizeof(struct xt_statistic_info),
73 .checkentry = checkentry,
74 .family = AF_INET,
75 .me = THIS_MODULE,
78 static struct xt_match statistic_match6 = {
79 .name = "statistic",
80 .match = match,
81 .matchsize = sizeof(struct xt_statistic_info),
82 .checkentry = checkentry,
83 .family = AF_INET6,
84 .me = THIS_MODULE,
87 static int __init xt_statistic_init(void)
89 int ret;
91 ret = xt_register_match(&statistic_match);
92 if (ret)
93 goto err1;
95 ret = xt_register_match(&statistic_match6);
96 if (ret)
97 goto err2;
98 return ret;
99 err2:
100 xt_unregister_match(&statistic_match);
101 err1:
102 return ret;
105 static void __exit xt_statistic_fini(void)
107 xt_unregister_match(&statistic_match6);
108 xt_unregister_match(&statistic_match);
111 module_init(xt_statistic_init);
112 module_exit(xt_statistic_fini);