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