[NETFILTER]: x_tables: switch xt_match->match to bool
[linux-2.6.git] / net / netfilter / xt_statistic.c
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>");
21 MODULE_DESCRIPTION("xtables statistical match module");
22 MODULE_ALIAS("ipt_statistic");
23 MODULE_ALIAS("ip6t_statistic");
24
25 static DEFINE_SPINLOCK(nth_lock);
26
27 static bool
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, bool *hotdrop)
32 {
33         struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
34         bool ret = info->flags & XT_STATISTIC_INVERT;
35
36         switch (info->mode) {
37         case XT_STATISTIC_MODE_RANDOM:
38                 if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
39                         ret = !ret;
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 = !ret;
47                 }
48                 spin_unlock_bh(&nth_lock);
49                 break;
50         }
51
52         return ret;
53 }
54
55 static int
56 checkentry(const char *tablename, const void *entry,
57            const struct xt_match *match, void *matchinfo,
58            unsigned int hook_mask)
59 {
60         struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
61
62         if (info->mode > XT_STATISTIC_MODE_MAX ||
63             info->flags & ~XT_STATISTIC_MASK)
64                 return 0;
65         info->master = info;
66         return 1;
67 }
68
69 static struct xt_match xt_statistic_match[] = {
70         {
71                 .name           = "statistic",
72                 .family         = AF_INET,
73                 .checkentry     = checkentry,
74                 .match          = match,
75                 .matchsize      = sizeof(struct xt_statistic_info),
76                 .me             = THIS_MODULE,
77         },
78         {
79                 .name           = "statistic",
80                 .family         = AF_INET6,
81                 .checkentry     = checkentry,
82                 .match          = match,
83                 .matchsize      = sizeof(struct xt_statistic_info),
84                 .me             = THIS_MODULE,
85         },
86 };
87
88 static int __init xt_statistic_init(void)
89 {
90         return xt_register_matches(xt_statistic_match,
91                                    ARRAY_SIZE(xt_statistic_match));
92 }
93
94 static void __exit xt_statistic_fini(void)
95 {
96         xt_unregister_matches(xt_statistic_match,
97                               ARRAY_SIZE(xt_statistic_match));
98 }
99
100 module_init(xt_statistic_init);
101 module_exit(xt_statistic_fini);