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Based on 2 normalized pattern(s): 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 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 # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
100 lines
2.4 KiB
C
100 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
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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/slab.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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#include <linux/module.h>
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struct xt_statistic_priv {
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atomic_t count;
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} ____cacheline_aligned_in_smp;
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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: statistics-based matching (\"Nth\", random)");
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MODULE_ALIAS("ipt_statistic");
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MODULE_ALIAS("ip6t_statistic");
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static bool
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statistic_mt(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_statistic_info *info = par->matchinfo;
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bool ret = info->flags & XT_STATISTIC_INVERT;
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int nval, oval;
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switch (info->mode) {
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case XT_STATISTIC_MODE_RANDOM:
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if ((prandom_u32() & 0x7FFFFFFF) < info->u.random.probability)
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ret = !ret;
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break;
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case XT_STATISTIC_MODE_NTH:
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do {
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oval = atomic_read(&info->master->count);
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nval = (oval == info->u.nth.every) ? 0 : oval + 1;
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} while (atomic_cmpxchg(&info->master->count, oval, nval) != oval);
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if (nval == 0)
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ret = !ret;
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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 statistic_mt_check(const struct xt_mtchk_param *par)
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{
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struct xt_statistic_info *info = par->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 -EINVAL;
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info->master = kzalloc(sizeof(*info->master), GFP_KERNEL);
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if (info->master == NULL)
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return -ENOMEM;
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atomic_set(&info->master->count, info->u.nth.count);
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return 0;
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}
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static void statistic_mt_destroy(const struct xt_mtdtor_param *par)
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{
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const struct xt_statistic_info *info = par->matchinfo;
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kfree(info->master);
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}
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static struct xt_match xt_statistic_mt_reg __read_mostly = {
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.name = "statistic",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.match = statistic_mt,
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.checkentry = statistic_mt_check,
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.destroy = statistic_mt_destroy,
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.matchsize = sizeof(struct xt_statistic_info),
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.usersize = offsetof(struct xt_statistic_info, master),
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.me = THIS_MODULE,
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};
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static int __init statistic_mt_init(void)
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{
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return xt_register_match(&xt_statistic_mt_reg);
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}
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static void __exit statistic_mt_exit(void)
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{
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xt_unregister_match(&xt_statistic_mt_reg);
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}
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module_init(statistic_mt_init);
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module_exit(statistic_mt_exit);
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