/*
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* Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
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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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#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/atomic.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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struct nft_quota {
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u64 quota;
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bool invert;
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atomic64_t remain;
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};
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static inline bool nft_overquota(struct nft_quota *priv,
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const struct nft_pktinfo *pkt)
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{
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return atomic64_sub_return(pkt->skb->len, &priv->remain) < 0;
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}
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static void nft_quota_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_quota *priv = nft_expr_priv(expr);
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if (nft_overquota(priv, pkt) ^ priv->invert)
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regs->verdict.code = NFT_BREAK;
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}
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static const struct nla_policy nft_quota_policy[NFTA_QUOTA_MAX + 1] = {
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[NFTA_QUOTA_BYTES] = { .type = NLA_U64 },
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[NFTA_QUOTA_FLAGS] = { .type = NLA_U32 },
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};
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static int nft_quota_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_quota *priv = nft_expr_priv(expr);
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u32 flags = 0;
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u64 quota;
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if (!tb[NFTA_QUOTA_BYTES])
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return -EINVAL;
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quota = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_BYTES]));
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if (quota > S64_MAX)
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return -EOVERFLOW;
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if (tb[NFTA_QUOTA_FLAGS]) {
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flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS]));
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if (flags & ~NFT_QUOTA_F_INV)
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return -EINVAL;
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}
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priv->quota = quota;
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priv->invert = (flags & NFT_QUOTA_F_INV) ? true : false;
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atomic64_set(&priv->remain, quota);
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return 0;
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}
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static int nft_quota_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_quota *priv = nft_expr_priv(expr);
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u32 flags = priv->invert ? NFT_QUOTA_F_INV : 0;
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if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(priv->quota),
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NFTA_QUOTA_PAD) ||
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nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
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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_quota_type;
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static const struct nft_expr_ops nft_quota_ops = {
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.type = &nft_quota_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_quota)),
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.eval = nft_quota_eval,
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.init = nft_quota_init,
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.dump = nft_quota_dump,
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};
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static struct nft_expr_type nft_quota_type __read_mostly = {
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.name = "quota",
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.ops = &nft_quota_ops,
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.policy = nft_quota_policy,
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.maxattr = NFTA_QUOTA_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_quota_module_init(void)
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{
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return nft_register_expr(&nft_quota_type);
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}
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static void __exit nft_quota_module_exit(void)
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{
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nft_unregister_expr(&nft_quota_type);
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}
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module_init(nft_quota_module_init);
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module_exit(nft_quota_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
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MODULE_ALIAS_NFT_EXPR("quota");
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