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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;
unsigned long flags;
atomic64_t consumed;
};
static inline bool nft_overquota(struct nft_quota *priv,
const struct sk_buff *skb)
{
return atomic64_add_return(skb->len, &priv->consumed) >= priv->quota;
}
static inline bool nft_quota_invert(struct nft_quota *priv)
{
return priv->flags & NFT_QUOTA_F_INV;
}
static inline void nft_quota_do_eval(struct nft_quota *priv,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
if (nft_overquota(priv, pkt->skb) ^ nft_quota_invert(priv))
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 },
[NFTA_QUOTA_CONSUMED] = { .type = NLA_U64 },
};
#define NFT_QUOTA_DEPLETED_BIT 1 /* From NFT_QUOTA_F_DEPLETED. */
static void nft_quota_obj_eval(struct nft_object *obj,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_quota *priv = nft_obj_data(obj);
bool overquota;
overquota = nft_overquota(priv, pkt->skb);
if (overquota ^ nft_quota_invert(priv))
regs->verdict.code = NFT_BREAK;
if (overquota &&
!test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags))
nft_obj_notify(nft_net(pkt), obj->key.table, obj, 0, 0,
NFT_MSG_NEWOBJ, nft_pf(pkt), 0, GFP_ATOMIC);
}
static int nft_quota_do_init(const struct nlattr * const tb[],
struct nft_quota *priv)
{
unsigned long flags = 0;
u64 quota, consumed = 0;
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_CONSUMED]) {
consumed = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_CONSUMED]));
if (consumed > quota)
return -EINVAL;
}
if (tb[NFTA_QUOTA_FLAGS]) {
flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS]));
if (flags & ~NFT_QUOTA_F_INV)
return -EINVAL;
if (flags & NFT_QUOTA_F_DEPLETED)
return -EOPNOTSUPP;
}
priv->quota = quota;
priv->flags = flags;
atomic64_set(&priv->consumed, consumed);
return 0;
}
static int nft_quota_obj_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[],
struct nft_object *obj)
{
struct nft_quota *priv = nft_obj_data(obj);
return nft_quota_do_init(tb, priv);
}
static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
bool reset)
{
u64 consumed, consumed_cap;
u32 flags = priv->flags;
/* Since we inconditionally increment consumed quota for each packet
* that we see, don't go over the quota boundary in what we send to
* userspace.
*/
consumed = atomic64_read(&priv->consumed);
if (consumed >= priv->quota) {
consumed_cap = priv->quota;
flags |= NFT_QUOTA_F_DEPLETED;
} else {
consumed_cap = consumed;
}
if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(priv->quota),
NFTA_QUOTA_PAD) ||
nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap),
NFTA_QUOTA_PAD) ||
nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
goto nla_put_failure;
if (reset) {
atomic64_sub(consumed, &priv->consumed);
clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags);
}
return 0;
nla_put_failure:
return -1;
}
static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj,
bool reset)
{
struct nft_quota *priv = nft_obj_data(obj);
return nft_quota_do_dump(skb, priv, reset);
}
static struct nft_object_type nft_quota_obj_type;
static const struct nft_object_ops nft_quota_obj_ops = {
.type = &nft_quota_obj_type,
.size = sizeof(struct nft_quota),
.init = nft_quota_obj_init,
.eval = nft_quota_obj_eval,
.dump = nft_quota_obj_dump,
};
static struct nft_object_type nft_quota_obj_type __read_mostly = {
.type = NFT_OBJECT_QUOTA,
.ops = &nft_quota_obj_ops,
.maxattr = NFTA_QUOTA_MAX,
.policy = nft_quota_policy,
.owner = THIS_MODULE,
};
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);
nft_quota_do_eval(priv, regs, pkt);
}
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);
return nft_quota_do_init(tb, priv);
}
static int nft_quota_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
struct nft_quota *priv = nft_expr_priv(expr);
return nft_quota_do_dump(skb, priv, false);
}
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)
{
int err;
err = nft_register_obj(&nft_quota_obj_type);
if (err < 0)
return err;
err = nft_register_expr(&nft_quota_type);
if (err < 0)
goto err1;
return 0;
err1:
nft_unregister_obj(&nft_quota_obj_type);
return err;
}
static void __exit nft_quota_module_exit(void)
{
nft_unregister_expr(&nft_quota_type);
nft_unregister_obj(&nft_quota_obj_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");
MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA);
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