102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
/*
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* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Based on ipt_random and ipt_nth by Fabrice MARIE <fabrice@netfilter.org>.
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*/
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/skbuff.h>
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#include <linux/net.h>
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#include <linux/netfilter/xt_statistic.h>
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#include <linux/netfilter/x_tables.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_DESCRIPTION("xtables statistical match module");
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MODULE_ALIAS("ipt_statistic");
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MODULE_ALIAS("ip6t_statistic");
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static DEFINE_SPINLOCK(nth_lock);
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static int
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match(const struct sk_buff *skb,
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const struct net_device *in, const struct net_device *out,
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const struct xt_match *match, const void *matchinfo,
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int offset, unsigned int protoff, int *hotdrop)
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{
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struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
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int ret = info->flags & XT_STATISTIC_INVERT ? 1 : 0;
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switch (info->mode) {
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case XT_STATISTIC_MODE_RANDOM:
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if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
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ret ^= 1;
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break;
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case XT_STATISTIC_MODE_NTH:
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info = info->master;
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spin_lock_bh(&nth_lock);
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if (info->u.nth.count++ == info->u.nth.every) {
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info->u.nth.count = 0;
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ret ^= 1;
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}
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spin_unlock_bh(&nth_lock);
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break;
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}
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return ret;
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}
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static int
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checkentry(const char *tablename, const void *entry,
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const struct xt_match *match, void *matchinfo,
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unsigned int hook_mask)
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{
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struct xt_statistic_info *info = (struct xt_statistic_info *)matchinfo;
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if (info->mode > XT_STATISTIC_MODE_MAX ||
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info->flags & ~XT_STATISTIC_MASK)
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return 0;
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info->master = info;
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return 1;
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}
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static struct xt_match xt_statistic_match[] = {
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{
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.name = "statistic",
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.family = AF_INET,
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.checkentry = checkentry,
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.match = match,
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.matchsize = sizeof(struct xt_statistic_info),
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.me = THIS_MODULE,
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},
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{
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.name = "statistic",
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.family = AF_INET6,
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.checkentry = checkentry,
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.match = match,
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.matchsize = sizeof(struct xt_statistic_info),
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.me = THIS_MODULE,
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},
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};
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static int __init xt_statistic_init(void)
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{
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return xt_register_matches(xt_statistic_match,
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ARRAY_SIZE(xt_statistic_match));
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}
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static void __exit xt_statistic_fini(void)
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{
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xt_unregister_matches(xt_statistic_match,
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ARRAY_SIZE(xt_statistic_match));
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}
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module_init(xt_statistic_init);
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module_exit(xt_statistic_fini);
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