[NETFILTER]: x_tables: add statistic match (f3389805) · Commits · e / devices / android_kernel_oneplus_sm7250

include/linux/netfilter/xt_statistic.h

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		#ifndef _XT_STATISTIC_H
		#define _XT_STATISTIC_H

		enum xt_statistic_mode {
		XT_STATISTIC_MODE_RANDOM,
		XT_STATISTIC_MODE_NTH,
		__XT_STATISTIC_MODE_MAX
		};
		#define XT_STATISTIC_MODE_MAX (__XT_STATISTIC_MODE_MAX - 1)

		enum xt_statistic_flags {
		XT_STATISTIC_INVERT = 0x1,
		};
		#define XT_STATISTIC_MASK 0x1

		struct xt_statistic_info {
		u_int16_t mode;
		u_int16_t flags;
		union {
		struct {
		u_int32_t probability;
		} random;
		struct {
		u_int32_t every;
		u_int32_t packet;
		u_int32_t count;
		} nth;
		} u;
		struct xt_statistic_info *master __attribute__((aligned(8)));
		};

		#endif /* _XT_STATISTIC_H */

net/netfilter/Kconfig

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Original line number	Diff line number	Diff line
		@@ -375,6 +375,12 @@ config NETFILTER_XT_MATCH_STATE

		To compile it as a module, choose M here. If unsure, say N.

		config NETFILTER_XT_MATCH_STATISTIC
		tristate '"statistic" match support'
		depends on NETFILTER_XTABLES
		help
		statistic module

		config NETFILTER_XT_MATCH_STRING
		tristate '"string" match support'
		depends on NETFILTER_XTABLES

net/netfilter/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -48,6 +48,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_QUOTA) += xt_quota.o
		obj-$(CONFIG_NETFILTER_XT_MATCH_REALM) += xt_realm.o
		obj-$(CONFIG_NETFILTER_XT_MATCH_SCTP) += xt_sctp.o
		obj-$(CONFIG_NETFILTER_XT_MATCH_STATE) += xt_state.o
		obj-$(CONFIG_NETFILTER_XT_MATCH_STATISTIC) += xt_statistic.o
		obj-$(CONFIG_NETFILTER_XT_MATCH_STRING) += xt_string.o
		obj-$(CONFIG_NETFILTER_XT_MATCH_TCPMSS) += xt_tcpmss.o
		obj-$(CONFIG_NETFILTER_XT_MATCH_PHYSDEV) += xt_physdev.o

net/netfilter/xt_statistic.c

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		/*
		* 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 statistical match module");
		MODULE_ALIAS("ipt_statistic");
		MODULE_ALIAS("ip6t_statistic");

		static DEFINE_SPINLOCK(nth_lock);

		static int
		match(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, int *hotdrop)
		{
		struct xt_statistic_info info = (struct xt_statistic_info )matchinfo;
		int ret = info->flags & XT_STATISTIC_INVERT ? 1 : 0;

		switch (info->mode) {
		case XT_STATISTIC_MODE_RANDOM:
		if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
		ret ^= 1;
		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 ^= 1;
		}
		spin_unlock_bh(&nth_lock);
		break;
		}

		return ret;
		}

		static int
		checkentry(const char tablename, const void entry,
		const struct xt_match match, void matchinfo,
		unsigned int matchsize, unsigned int hook_mask)
		{
		struct xt_statistic_info info = (struct xt_statistic_info )matchinfo;

		if (info->mode > XT_STATISTIC_MODE_MAX \|\|
		info->flags & ~XT_STATISTIC_MASK)
		return 0;
		info->master = info;
		return 1;
		}

		static struct xt_match statistic_match = {
		.name = "statistic",
		.match = match,
		.matchsize = sizeof(struct xt_statistic_info),
		.checkentry = checkentry,
		.family = AF_INET,
		.me = THIS_MODULE,
		};

		static struct xt_match statistic_match6 = {
		.name = "statistic",
		.match = match,
		.matchsize = sizeof(struct xt_statistic_info),
		.checkentry = checkentry,
		.family = AF_INET6,
		.me = THIS_MODULE,
		};

		static int __init xt_statistic_init(void)
		{
		int ret;

		ret = xt_register_match(&statistic_match);
		if (ret)
		goto err1;

		ret = xt_register_match(&statistic_match6);
		if (ret)
		goto err2;
		return ret;
		err2:
		xt_unregister_match(&statistic_match);
		err1:
		return ret;
		}

		static void __exit xt_statistic_fini(void)
		{
		xt_unregister_match(&statistic_match6);
		xt_unregister_match(&statistic_match);
		}

		module_init(xt_statistic_init);
		module_exit(xt_statistic_fini);