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>.
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: statistics-based matching (\"Nth\", random)");
22 MODULE_ALIAS("ipt_statistic");
23 MODULE_ALIAS("ip6t_statistic");
25 static DEFINE_SPINLOCK(nth_lock
);
28 statistic_mt(const struct sk_buff
*skb
, const struct xt_match_param
*par
)
30 struct xt_statistic_info
*info
= (void *)par
->matchinfo
;
31 bool ret
= info
->flags
& XT_STATISTIC_INVERT
;
34 case XT_STATISTIC_MODE_RANDOM
:
35 if ((net_random() & 0x7FFFFFFF) < info
->u
.random
.probability
)
38 case XT_STATISTIC_MODE_NTH
:
40 spin_lock_bh(&nth_lock
);
41 if (info
->u
.nth
.count
++ == info
->u
.nth
.every
) {
42 info
->u
.nth
.count
= 0;
45 spin_unlock_bh(&nth_lock
);
53 statistic_mt_check(const char *tablename
, const void *entry
,
54 const struct xt_match
*match
, void *matchinfo
,
55 unsigned int hook_mask
)
57 struct xt_statistic_info
*info
= matchinfo
;
59 if (info
->mode
> XT_STATISTIC_MODE_MAX
||
60 info
->flags
& ~XT_STATISTIC_MASK
)
66 static struct xt_match xt_statistic_mt_reg __read_mostly
= {
69 .family
= NFPROTO_UNSPEC
,
70 .match
= statistic_mt
,
71 .checkentry
= statistic_mt_check
,
72 .matchsize
= sizeof(struct xt_statistic_info
),
76 static int __init
statistic_mt_init(void)
78 return xt_register_match(&xt_statistic_mt_reg
);
81 static void __exit
statistic_mt_exit(void)
83 xt_unregister_match(&xt_statistic_mt_reg
);
86 module_init(statistic_mt_init
);
87 module_exit(statistic_mt_exit
);