// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
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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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atomic64_t quota;
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unsigned long flags;
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atomic64_t consumed;
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};
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static inline bool nft_overquota(struct nft_quota *priv,
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const struct sk_buff *skb)
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{
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return atomic64_add_return(skb->len, &priv->consumed) >=
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atomic64_read(&priv->quota);
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}
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static inline bool nft_quota_invert(struct nft_quota *priv)
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{
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return priv->flags & NFT_QUOTA_F_INV;
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}
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static inline void nft_quota_do_eval(struct nft_quota *priv,
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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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if (nft_overquota(priv, pkt->skb) ^ nft_quota_invert(priv))
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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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[NFTA_QUOTA_CONSUMED] = { .type = NLA_U64 },
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};
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#define NFT_QUOTA_DEPLETED_BIT 1 /* From NFT_QUOTA_F_DEPLETED. */
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static void nft_quota_obj_eval(struct nft_object *obj,
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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_obj_data(obj);
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bool overquota;
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overquota = nft_overquota(priv, pkt->skb);
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if (overquota ^ nft_quota_invert(priv))
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regs->verdict.code = NFT_BREAK;
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if (overquota &&
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!test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags))
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nft_obj_notify(nft_net(pkt), obj->key.table, obj, 0, 0,
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NFT_MSG_NEWOBJ, nft_pf(pkt), 0, GFP_ATOMIC);
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}
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static int nft_quota_do_init(const struct nlattr * const tb[],
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struct nft_quota *priv)
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{
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unsigned long flags = 0;
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u64 quota, consumed = 0;
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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_CONSUMED]) {
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consumed = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_CONSUMED]));
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if (consumed > quota)
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return -EINVAL;
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}
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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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if (flags & NFT_QUOTA_F_DEPLETED)
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return -EOPNOTSUPP;
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}
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atomic64_set(&priv->quota, quota);
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priv->flags = flags;
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atomic64_set(&priv->consumed, consumed);
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return 0;
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}
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static int nft_quota_obj_init(const struct nft_ctx *ctx,
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const struct nlattr * const tb[],
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struct nft_object *obj)
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{
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struct nft_quota *priv = nft_obj_data(obj);
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return nft_quota_do_init(tb, priv);
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}
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static void nft_quota_obj_update(struct nft_object *obj,
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struct nft_object *newobj)
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{
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struct nft_quota *newpriv = nft_obj_data(newobj);
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struct nft_quota *priv = nft_obj_data(obj);
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u64 newquota;
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newquota = atomic64_read(&newpriv->quota);
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atomic64_set(&priv->quota, newquota);
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priv->flags = newpriv->flags;
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}
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static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
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bool reset)
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{
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u64 consumed, consumed_cap, quota;
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u32 flags = priv->flags;
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/* Since we inconditionally increment consumed quota for each packet
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* that we see, don't go over the quota boundary in what we send to
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* userspace.
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*/
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consumed = atomic64_read(&priv->consumed);
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quota = atomic64_read(&priv->quota);
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if (consumed >= quota) {
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consumed_cap = quota;
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flags |= NFT_QUOTA_F_DEPLETED;
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} else {
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consumed_cap = consumed;
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}
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if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(quota),
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NFTA_QUOTA_PAD) ||
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nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap),
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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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if (reset) {
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atomic64_sub(consumed, &priv->consumed);
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clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags);
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}
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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 int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj,
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bool reset)
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{
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struct nft_quota *priv = nft_obj_data(obj);
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return nft_quota_do_dump(skb, priv, reset);
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}
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static struct nft_object_type nft_quota_obj_type;
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static const struct nft_object_ops nft_quota_obj_ops = {
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.type = &nft_quota_obj_type,
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.size = sizeof(struct nft_quota),
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.init = nft_quota_obj_init,
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.eval = nft_quota_obj_eval,
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.dump = nft_quota_obj_dump,
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.update = nft_quota_obj_update,
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};
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static struct nft_object_type nft_quota_obj_type __read_mostly = {
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.type = NFT_OBJECT_QUOTA,
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.ops = &nft_quota_obj_ops,
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.maxattr = NFTA_QUOTA_MAX,
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.policy = nft_quota_policy,
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.owner = THIS_MODULE,
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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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nft_quota_do_eval(priv, regs, pkt);
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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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return nft_quota_do_init(tb, priv);
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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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struct nft_quota *priv = nft_expr_priv(expr);
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return nft_quota_do_dump(skb, priv, false);
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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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int err;
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err = nft_register_obj(&nft_quota_obj_type);
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if (err < 0)
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return err;
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err = nft_register_expr(&nft_quota_type);
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if (err < 0)
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goto err1;
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return 0;
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err1:
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nft_unregister_obj(&nft_quota_obj_type);
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return err;
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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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nft_unregister_obj(&nft_quota_obj_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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MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA);
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MODULE_DESCRIPTION("Netfilter nftables quota module");
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