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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 15 | #include <linux/slab.h> |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 16 | |
| 17 | #include <linux/netfilter/xt_statistic.h> |
| 18 | #include <linux/netfilter/x_tables.h> |
Paul Gortmaker | 3a9a231 | 2011-05-27 09:12:25 -0400 | [diff] [blame] | 19 | #include <linux/module.h> |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 20 | |
Jan Engelhardt | acc738f | 2009-03-16 15:35:29 +0100 | [diff] [blame] | 21 | struct xt_statistic_priv { |
Eric Dumazet | fabf3a8 | 2010-06-01 12:00:41 +0200 | [diff] [blame] | 22 | atomic_t count; |
| 23 | } ____cacheline_aligned_in_smp; |
Jan Engelhardt | acc738f | 2009-03-16 15:35:29 +0100 | [diff] [blame] | 24 | |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 25 | MODULE_LICENSE("GPL"); |
| 26 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 27 | MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)"); |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 28 | MODULE_ALIAS("ipt_statistic"); |
| 29 | MODULE_ALIAS("ip6t_statistic"); |
| 30 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 31 | static bool |
Jan Engelhardt | 62fc805 | 2009-07-07 20:42:08 +0200 | [diff] [blame] | 32 | statistic_mt(const struct sk_buff *skb, struct xt_action_param *par) |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 33 | { |
Jan Engelhardt | acc738f | 2009-03-16 15:35:29 +0100 | [diff] [blame] | 34 | const struct xt_statistic_info *info = par->matchinfo; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 35 | bool ret = info->flags & XT_STATISTIC_INVERT; |
Eric Dumazet | fabf3a8 | 2010-06-01 12:00:41 +0200 | [diff] [blame] | 36 | int nval, oval; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 37 | |
| 38 | switch (info->mode) { |
| 39 | case XT_STATISTIC_MODE_RANDOM: |
| 40 | if ((net_random() & 0x7FFFFFFF) < info->u.random.probability) |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 41 | ret = !ret; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 42 | break; |
| 43 | case XT_STATISTIC_MODE_NTH: |
Eric Dumazet | fabf3a8 | 2010-06-01 12:00:41 +0200 | [diff] [blame] | 44 | do { |
| 45 | oval = atomic_read(&info->master->count); |
| 46 | nval = (oval == info->u.nth.every) ? 0 : oval + 1; |
| 47 | } while (atomic_cmpxchg(&info->master->count, oval, nval) != oval); |
| 48 | if (nval == 0) |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 49 | ret = !ret; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 50 | break; |
| 51 | } |
| 52 | |
| 53 | return ret; |
| 54 | } |
| 55 | |
Jan Engelhardt | b0f3845 | 2010-03-19 17:16:42 +0100 | [diff] [blame] | 56 | static int statistic_mt_check(const struct xt_mtchk_param *par) |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 57 | { |
Jan Engelhardt | 9b4fce7 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 58 | struct xt_statistic_info *info = par->matchinfo; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 59 | |
| 60 | if (info->mode > XT_STATISTIC_MODE_MAX || |
| 61 | info->flags & ~XT_STATISTIC_MASK) |
Jan Engelhardt | bd414ee | 2010-03-23 16:35:56 +0100 | [diff] [blame] | 62 | return -EINVAL; |
Jan Engelhardt | acc738f | 2009-03-16 15:35:29 +0100 | [diff] [blame] | 63 | |
| 64 | info->master = kzalloc(sizeof(*info->master), GFP_KERNEL); |
Jan Engelhardt | 85bc3f3 | 2010-03-18 00:27:03 +0100 | [diff] [blame] | 65 | if (info->master == NULL) |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 66 | return -ENOMEM; |
Eric Dumazet | fabf3a8 | 2010-06-01 12:00:41 +0200 | [diff] [blame] | 67 | atomic_set(&info->master->count, info->u.nth.count); |
Jan Engelhardt | acc738f | 2009-03-16 15:35:29 +0100 | [diff] [blame] | 68 | |
Jan Engelhardt | bd414ee | 2010-03-23 16:35:56 +0100 | [diff] [blame] | 69 | return 0; |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 70 | } |
| 71 | |
Jan Engelhardt | acc738f | 2009-03-16 15:35:29 +0100 | [diff] [blame] | 72 | static void statistic_mt_destroy(const struct xt_mtdtor_param *par) |
| 73 | { |
| 74 | const struct xt_statistic_info *info = par->matchinfo; |
| 75 | |
| 76 | kfree(info->master); |
| 77 | } |
| 78 | |
Jan Engelhardt | 55b69e9 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 79 | static struct xt_match xt_statistic_mt_reg __read_mostly = { |
| 80 | .name = "statistic", |
| 81 | .revision = 0, |
| 82 | .family = NFPROTO_UNSPEC, |
| 83 | .match = statistic_mt, |
| 84 | .checkentry = statistic_mt_check, |
Jan Engelhardt | acc738f | 2009-03-16 15:35:29 +0100 | [diff] [blame] | 85 | .destroy = statistic_mt_destroy, |
Jan Engelhardt | 55b69e9 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 86 | .matchsize = sizeof(struct xt_statistic_info), |
| 87 | .me = THIS_MODULE, |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 88 | }; |
| 89 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 90 | static int __init statistic_mt_init(void) |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 91 | { |
Jan Engelhardt | 55b69e9 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 92 | return xt_register_match(&xt_statistic_mt_reg); |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 93 | } |
| 94 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 95 | static void __exit statistic_mt_exit(void) |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 96 | { |
Jan Engelhardt | 55b69e9 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 97 | xt_unregister_match(&xt_statistic_mt_reg); |
Patrick McHardy | f338980 | 2006-05-29 18:21:00 -0700 | [diff] [blame] | 98 | } |
| 99 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 100 | module_init(statistic_mt_init); |
| 101 | module_exit(statistic_mt_exit); |