Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 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>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 21 | MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)"); |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 22 | MODULE_ALIAS("ipt_statistic"); |
| 23 | MODULE_ALIAS("ip6t_statistic"); |
| 24 | |
| 25 | static DEFINE_SPINLOCK(nth_lock); |
| 26 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 27 | static bool |
Jan Engelhardt | f7108a2 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 28 | statistic_mt(const struct sk_buff *skb, const struct xt_match_param *par) |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 29 | { |
Jan Engelhardt | f7108a2 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 30 | struct xt_statistic_info *info = (void *)par->matchinfo; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 31 | bool ret = info->flags & XT_STATISTIC_INVERT; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 32 | |
| 33 | switch (info->mode) { |
| 34 | case XT_STATISTIC_MODE_RANDOM: |
| 35 | if ((net_random() & 0x7FFFFFFF) < info->u.random.probability) |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 36 | ret = !ret; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 37 | break; |
| 38 | case XT_STATISTIC_MODE_NTH: |
| 39 | info = info->master; |
| 40 | spin_lock_bh(&nth_lock); |
| 41 | if (info->u.nth.count++ == info->u.nth.every) { |
| 42 | info->u.nth.count = 0; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 43 | ret = !ret; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 44 | } |
| 45 | spin_unlock_bh(&nth_lock); |
| 46 | break; |
| 47 | } |
| 48 | |
| 49 | return ret; |
| 50 | } |
| 51 | |
Jan Engelhardt | 9b4fce7 | 2008-10-08 11:35:18 +0200 | [diff] [blame^] | 52 | static bool statistic_mt_check(const struct xt_mtchk_param *par) |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 53 | { |
Jan Engelhardt | 9b4fce7 | 2008-10-08 11:35:18 +0200 | [diff] [blame^] | 54 | struct xt_statistic_info *info = par->matchinfo; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 55 | |
| 56 | if (info->mode > XT_STATISTIC_MODE_MAX || |
| 57 | info->flags & ~XT_STATISTIC_MASK) |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 58 | return false; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 59 | info->master = info; |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 60 | return true; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 61 | } |
| 62 | |
Jan Engelhardt | 55b69e9 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 63 | static struct xt_match xt_statistic_mt_reg __read_mostly = { |
| 64 | .name = "statistic", |
| 65 | .revision = 0, |
| 66 | .family = NFPROTO_UNSPEC, |
| 67 | .match = statistic_mt, |
| 68 | .checkentry = statistic_mt_check, |
| 69 | .matchsize = sizeof(struct xt_statistic_info), |
| 70 | .me = THIS_MODULE, |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 71 | }; |
| 72 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 73 | static int __init statistic_mt_init(void) |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 74 | { |
Jan Engelhardt | 55b69e9 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 75 | return xt_register_match(&xt_statistic_mt_reg); |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 76 | } |
| 77 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 78 | static void __exit statistic_mt_exit(void) |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 79 | { |
Jan Engelhardt | 55b69e9 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 80 | xt_unregister_match(&xt_statistic_mt_reg); |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 81 | } |
| 82 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 83 | module_init(statistic_mt_init); |
| 84 | module_exit(statistic_mt_exit); |