ef1f7df917
Split the expression ops into two parts and support overloading of the runtime expression ops based on the requested function through a ->select_ops() callback. This can be used to provide optimized implementations, for instance for loading small aligned amounts of data from the packet or inlining frequently used operations into the main evaluation loop. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
120 lines
2.9 KiB
C
120 lines
2.9 KiB
C
/*
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* Copyright (c) 2008-2009 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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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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static DEFINE_SPINLOCK(limit_lock);
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struct nft_limit {
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u64 tokens;
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u64 rate;
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u64 unit;
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unsigned long stamp;
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};
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static void nft_limit_eval(const struct nft_expr *expr,
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struct nft_data data[NFT_REG_MAX + 1],
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const struct nft_pktinfo *pkt)
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{
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struct nft_limit *priv = nft_expr_priv(expr);
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spin_lock_bh(&limit_lock);
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if (time_after_eq(jiffies, priv->stamp)) {
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priv->tokens = priv->rate;
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priv->stamp = jiffies + priv->unit * HZ;
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}
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if (priv->tokens >= 1) {
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priv->tokens--;
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spin_unlock_bh(&limit_lock);
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return;
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}
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spin_unlock_bh(&limit_lock);
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data[NFT_REG_VERDICT].verdict = NFT_BREAK;
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}
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static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
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[NFTA_LIMIT_RATE] = { .type = NLA_U64 },
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[NFTA_LIMIT_UNIT] = { .type = NLA_U64 },
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};
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static int nft_limit_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_limit *priv = nft_expr_priv(expr);
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if (tb[NFTA_LIMIT_RATE] == NULL ||
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tb[NFTA_LIMIT_UNIT] == NULL)
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return -EINVAL;
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priv->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
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priv->unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
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priv->stamp = jiffies + priv->unit * HZ;
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priv->tokens = priv->rate;
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return 0;
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}
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static int nft_limit_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_limit *priv = nft_expr_priv(expr);
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if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate)))
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goto nla_put_failure;
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if (nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(priv->unit)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static struct nft_expr_type nft_limit_type;
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static const struct nft_expr_ops nft_limit_ops = {
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.type = &nft_limit_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_limit)),
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.eval = nft_limit_eval,
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.init = nft_limit_init,
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.dump = nft_limit_dump,
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};
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static struct nft_expr_type nft_limit_type __read_mostly = {
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.name = "limit",
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.ops = &nft_limit_ops,
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.policy = nft_limit_policy,
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.maxattr = NFTA_LIMIT_MAX,
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.owner = THIS_MODULE,
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};
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static int __init nft_limit_module_init(void)
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{
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return nft_register_expr(&nft_limit_type);
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}
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static void __exit nft_limit_module_exit(void)
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{
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nft_unregister_expr(&nft_limit_type);
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}
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module_init(nft_limit_module_init);
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module_exit(nft_limit_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_ALIAS_NFT_EXPR("limit");
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