![Jan Engelhardt](/assets/img/avatar_default.png)
When a match or target is looked up using xt_find_{match,target}, Xtables will also search the NFPROTO_UNSPEC module list. This allows for protocol-independent extensions (like xt_time) to be reused from other components (e.g. arptables, ebtables). Extensions that take different codepaths depending on match->family or target->family of course cannot use NFPROTO_UNSPEC within the registration structure (e.g. xt_pkttype). Signed-off-by: Jan Engelhardt <jengelh@medozas.de> Signed-off-by: Patrick McHardy <kaber@trash.net>
91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/*
|
|
* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* Based on ipt_random and ipt_nth by Fabrice MARIE <fabrice@netfilter.org>.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/net.h>
|
|
|
|
#include <linux/netfilter/xt_statistic.h>
|
|
#include <linux/netfilter/x_tables.h>
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
|
|
MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)");
|
|
MODULE_ALIAS("ipt_statistic");
|
|
MODULE_ALIAS("ip6t_statistic");
|
|
|
|
static DEFINE_SPINLOCK(nth_lock);
|
|
|
|
static bool
|
|
statistic_mt(const struct sk_buff *skb, const struct net_device *in,
|
|
const struct net_device *out, const struct xt_match *match,
|
|
const void *matchinfo, int offset, unsigned int protoff,
|
|
bool *hotdrop)
|
|
{
|
|
struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
|
|
bool ret = info->flags & XT_STATISTIC_INVERT;
|
|
|
|
switch (info->mode) {
|
|
case XT_STATISTIC_MODE_RANDOM:
|
|
if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
|
|
ret = !ret;
|
|
break;
|
|
case XT_STATISTIC_MODE_NTH:
|
|
info = info->master;
|
|
spin_lock_bh(&nth_lock);
|
|
if (info->u.nth.count++ == info->u.nth.every) {
|
|
info->u.nth.count = 0;
|
|
ret = !ret;
|
|
}
|
|
spin_unlock_bh(&nth_lock);
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool
|
|
statistic_mt_check(const char *tablename, const void *entry,
|
|
const struct xt_match *match, void *matchinfo,
|
|
unsigned int hook_mask)
|
|
{
|
|
struct xt_statistic_info *info = matchinfo;
|
|
|
|
if (info->mode > XT_STATISTIC_MODE_MAX ||
|
|
info->flags & ~XT_STATISTIC_MASK)
|
|
return false;
|
|
info->master = info;
|
|
return true;
|
|
}
|
|
|
|
static struct xt_match xt_statistic_mt_reg __read_mostly = {
|
|
.name = "statistic",
|
|
.revision = 0,
|
|
.family = NFPROTO_UNSPEC,
|
|
.match = statistic_mt,
|
|
.checkentry = statistic_mt_check,
|
|
.matchsize = sizeof(struct xt_statistic_info),
|
|
.me = THIS_MODULE,
|
|
};
|
|
|
|
static int __init statistic_mt_init(void)
|
|
{
|
|
return xt_register_match(&xt_statistic_mt_reg);
|
|
}
|
|
|
|
static void __exit statistic_mt_exit(void)
|
|
{
|
|
xt_unregister_match(&xt_statistic_mt_reg);
|
|
}
|
|
|
|
module_init(statistic_mt_init);
|
|
module_exit(statistic_mt_exit);
|