151d799a61
Add a flag to mark stateful expressions. This is used for dynamic expression instanstiation to limit the usable expressions. Strictly speaking only the dynset expression can not be used in order to avoid recursion, but since dynamically instantiating non-stateful expressions will simply create an identical copy, which behaves no differently than the original, this limits to expressions where it actually makes sense to dynamically instantiate them. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
121 lines
2.9 KiB
C
121 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_regs *regs,
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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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regs->verdict.code = 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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.flags = NFT_EXPR_STATEFUL,
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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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