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/*
* Copyright (c) 2008-2009 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.
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
static DEFINE_SPINLOCK(limit_lock);
struct nft_limit {
u64 tokens;
u64 rate;
u64 unit;
unsigned long stamp;
};
static void nft_limit_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_limit *priv = nft_expr_priv(expr);
spin_lock_bh(&limit_lock);
if (time_after_eq(jiffies, priv->stamp)) {
priv->tokens = priv->rate;
priv->stamp = jiffies + priv->unit * HZ;
}
if (priv->tokens >= 1) {
priv->tokens--;
spin_unlock_bh(&limit_lock);
return;
}
spin_unlock_bh(&limit_lock);
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
[NFTA_LIMIT_RATE] = { .type = NLA_U64 },
[NFTA_LIMIT_UNIT] = { .type = NLA_U64 },
};
static int nft_limit_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_limit *priv = nft_expr_priv(expr);
if (tb[NFTA_LIMIT_RATE] == NULL ||
tb[NFTA_LIMIT_UNIT] == NULL)
return -EINVAL;
priv->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
priv->unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
priv->stamp = jiffies + priv->unit * HZ;
priv->tokens = priv->rate;
return 0;
}
static int nft_limit_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_limit *priv = nft_expr_priv(expr);
if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate)))
goto nla_put_failure;
if (nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(priv->unit)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_limit_type;
static const struct nft_expr_ops nft_limit_ops = {
.type = &nft_limit_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_limit)),
.eval = nft_limit_eval,
.init = nft_limit_init,
.dump = nft_limit_dump,
};
static struct nft_expr_type nft_limit_type __read_mostly = {
.name = "limit",
.ops = &nft_limit_ops,
.policy = nft_limit_policy,
.maxattr = NFTA_LIMIT_MAX,
.flags = NFT_EXPR_STATEFUL,
.owner = THIS_MODULE,
};
static int __init nft_limit_module_init(void)
{
return nft_register_expr(&nft_limit_type);
}
static void __exit nft_limit_module_exit(void)
{
nft_unregister_expr(&nft_limit_type);
}
module_init(nft_limit_module_init);
module_exit(nft_limit_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_EXPR("limit");
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