net/netfilter/nft_limit.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
  *
  * Development of this code funded by Astaro AG (http://www.astaro.com/)
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
 #include <linux/netlink.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables.h>

 struct nft_limit {
 	spinlock_t	lock;
 	u64		last;
 	u64		tokens;
 	u64		tokens_max;
 	u64		rate;
 	u64		nsecs;
 	u32		burst;
 	bool		invert;
 };

 static inline bool nft_limit_eval(struct nft_limit *limit, u64 cost)
 {
 	u64 now, tokens;
 	s64 delta;

 	spin_lock_bh(&limit->lock);
 	now = ktime_get_ns();
 	tokens = limit->tokens + now - limit->last;
 	if (tokens > limit->tokens_max)
 		tokens = limit->tokens_max;

 	limit->last = now;
 	delta = tokens - cost;
 	if (delta >= 0) {
 		limit->tokens = delta;
 		spin_unlock_bh(&limit->lock);
 		return limit->invert;
 	}
 	limit->tokens = tokens;
 	spin_unlock_bh(&limit->lock);
 	return !limit->invert;
 }

 /* Use same default as in iptables. */
 #define NFT_LIMIT_PKT_BURST_DEFAULT	5

 static int nft_limit_init(struct nft_limit *limit,
 			  const struct nlattr * const tb[], bool pkts)
 {
 	u64 unit, tokens;

 	if (tb[NFTA_LIMIT_RATE] == NULL ||
 	    tb[NFTA_LIMIT_UNIT] == NULL)
 		return -EINVAL;

 	limit->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
 	unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
 	limit->nsecs = unit * NSEC_PER_SEC;
 	if (limit->rate == 0 || limit->nsecs < unit)
 		return -EOVERFLOW;

 	if (tb[NFTA_LIMIT_BURST])
 		limit->burst = ntohl(nla_get_be32(tb[NFTA_LIMIT_BURST]));

 	if (pkts && limit->burst == 0)
 		limit->burst = NFT_LIMIT_PKT_BURST_DEFAULT;

 	if (limit->rate + limit->burst < limit->rate)
 		return -EOVERFLOW;

 	if (pkts) {
 		tokens = div_u64(limit->nsecs, limit->rate) * limit->burst;
 	} else {
 		/* The token bucket size limits the number of tokens can be
 		 * accumulated. tokens_max specifies the bucket size.
 		 * tokens_max = unit * (rate + burst) / rate.
 		 */
 		tokens = div_u64(limit->nsecs * (limit->rate + limit->burst),
 				 limit->rate);
 	}

 	limit->tokens = tokens;
 	limit->tokens_max = limit->tokens;

 	if (tb[NFTA_LIMIT_FLAGS]) {
 		u32 flags = ntohl(nla_get_be32(tb[NFTA_LIMIT_FLAGS]));

 		if (flags & NFT_LIMIT_F_INV)
 			limit->invert = true;
 	}
 	limit->last = ktime_get_ns();
 	spin_lock_init(&limit->lock);

 	return 0;
 }

 static int nft_limit_dump(struct sk_buff *skb, const struct nft_limit *limit,
 			  enum nft_limit_type type)
 {
 	u32 flags = limit->invert ? NFT_LIMIT_F_INV : 0;
 	u64 secs = div_u64(limit->nsecs, NSEC_PER_SEC);

 	if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(limit->rate),
 			 NFTA_LIMIT_PAD) ||
 	    nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs),
 			 NFTA_LIMIT_PAD) ||
 	    nla_put_be32(skb, NFTA_LIMIT_BURST, htonl(limit->burst)) ||
 	    nla_put_be32(skb, NFTA_LIMIT_TYPE, htonl(type)) ||
 	    nla_put_be32(skb, NFTA_LIMIT_FLAGS, htonl(flags)))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }

 struct nft_limit_pkts {
 	struct nft_limit	limit;
 	u64			cost;
 };

 static void nft_limit_pkts_eval(const struct nft_expr *expr,
 				struct nft_regs *regs,
 				const struct nft_pktinfo *pkt)
 {
 	struct nft_limit_pkts *priv = nft_expr_priv(expr);

 	if (nft_limit_eval(&priv->limit, priv->cost))
 		regs->verdict.code = NFT_BREAK;
 }

 static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
 	[NFTA_LIMIT_RATE]	= { .type = NLA_U64 },
 	[NFTA_LIMIT_UNIT]	= { .type = NLA_U64 },
 	[NFTA_LIMIT_BURST]	= { .type = NLA_U32 },
 	[NFTA_LIMIT_TYPE]	= { .type = NLA_U32 },
 	[NFTA_LIMIT_FLAGS]	= { .type = NLA_U32 },
 };

 static int nft_limit_pkts_init(const struct nft_ctx *ctx,
 			       const struct nft_expr *expr,
 			       const struct nlattr * const tb[])
 {
 	struct nft_limit_pkts *priv = nft_expr_priv(expr);
 	int err;

 	err = nft_limit_init(&priv->limit, tb, true);
 	if (err < 0)
 		return err;

 	priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate);
 	return 0;
 }

 static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
 	const struct nft_limit_pkts *priv = nft_expr_priv(expr);

 	return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
 }

 static struct nft_expr_type nft_limit_type;
 static const struct nft_expr_ops nft_limit_pkts_ops = {
 	.type		= &nft_limit_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_limit_pkts)),
 	.eval		= nft_limit_pkts_eval,
 	.init		= nft_limit_pkts_init,
 	.dump		= nft_limit_pkts_dump,
 };

 static void nft_limit_bytes_eval(const struct nft_expr *expr,
 				 struct nft_regs *regs,
 				 const struct nft_pktinfo *pkt)
 {
 	struct nft_limit *priv = nft_expr_priv(expr);
 	u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate);

 	if (nft_limit_eval(priv, cost))
 		regs->verdict.code = NFT_BREAK;
 }

 static int nft_limit_bytes_init(const struct nft_ctx *ctx,
 				const struct nft_expr *expr,
 				const struct nlattr * const tb[])
 {
 	struct nft_limit *priv = nft_expr_priv(expr);

 	return nft_limit_init(priv, tb, false);
 }

 static int nft_limit_bytes_dump(struct sk_buff *skb,
 				const struct nft_expr *expr)
 {
 	const struct nft_limit *priv = nft_expr_priv(expr);

 	return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
 }

 static const struct nft_expr_ops nft_limit_bytes_ops = {
 	.type		= &nft_limit_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_limit)),
 	.eval		= nft_limit_bytes_eval,
 	.init		= nft_limit_bytes_init,
 	.dump		= nft_limit_bytes_dump,
 };

 static const struct nft_expr_ops *
 nft_limit_select_ops(const struct nft_ctx *ctx,
 		     const struct nlattr * const tb[])
 {
 	if (tb[NFTA_LIMIT_TYPE] == NULL)
 		return &nft_limit_pkts_ops;

 	switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) {
 	case NFT_LIMIT_PKTS:
 		return &nft_limit_pkts_ops;
 	case NFT_LIMIT_PKT_BYTES:
 		return &nft_limit_bytes_ops;
 	}
 	return ERR_PTR(-EOPNOTSUPP);
 }

 static struct nft_expr_type nft_limit_type __read_mostly = {
 	.name		= "limit",
 	.select_ops	= nft_limit_select_ops,
 	.policy		= nft_limit_policy,
 	.maxattr	= NFTA_LIMIT_MAX,
 	.flags		= NFT_EXPR_STATEFUL,
 	.owner		= THIS_MODULE,
 };

 static void nft_limit_obj_pkts_eval(struct nft_object *obj,
 				    struct nft_regs *regs,
 				    const struct nft_pktinfo *pkt)
 {
 	struct nft_limit_pkts *priv = nft_obj_data(obj);

 	if (nft_limit_eval(&priv->limit, priv->cost))
 		regs->verdict.code = NFT_BREAK;
 }

 static int nft_limit_obj_pkts_init(const struct nft_ctx *ctx,
 				   const struct nlattr * const tb[],
 				   struct nft_object *obj)
 {
 	struct nft_limit_pkts *priv = nft_obj_data(obj);
 	int err;

 	err = nft_limit_init(&priv->limit, tb, true);
 	if (err < 0)
 		return err;

 	priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate);
 	return 0;
 }

 static int nft_limit_obj_pkts_dump(struct sk_buff *skb,
 				   struct nft_object *obj,
 				   bool reset)
 {
 	const struct nft_limit_pkts *priv = nft_obj_data(obj);

 	return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
 }

 static struct nft_object_type nft_limit_obj_type;
 static const struct nft_object_ops nft_limit_obj_pkts_ops = {
 	.type		= &nft_limit_obj_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_limit_pkts)),
 	.init		= nft_limit_obj_pkts_init,
 	.eval		= nft_limit_obj_pkts_eval,
 	.dump		= nft_limit_obj_pkts_dump,
 };

 static void nft_limit_obj_bytes_eval(struct nft_object *obj,
 				     struct nft_regs *regs,
 				     const struct nft_pktinfo *pkt)
 {
 	struct nft_limit *priv = nft_obj_data(obj);
 	u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate);

 	if (nft_limit_eval(priv, cost))
 		regs->verdict.code = NFT_BREAK;
 }

 static int nft_limit_obj_bytes_init(const struct nft_ctx *ctx,
 				    const struct nlattr * const tb[],
 				    struct nft_object *obj)
 {
 	struct nft_limit *priv = nft_obj_data(obj);

 	return nft_limit_init(priv, tb, false);
 }

 static int nft_limit_obj_bytes_dump(struct sk_buff *skb,
 				    struct nft_object *obj,
 				    bool reset)
 {
 	const struct nft_limit *priv = nft_obj_data(obj);

 	return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
 }

 static struct nft_object_type nft_limit_obj_type;
 static const struct nft_object_ops nft_limit_obj_bytes_ops = {
 	.type		= &nft_limit_obj_type,
 	.size		= sizeof(struct nft_limit),
 	.init		= nft_limit_obj_bytes_init,
 	.eval		= nft_limit_obj_bytes_eval,
 	.dump		= nft_limit_obj_bytes_dump,
 };

 static const struct nft_object_ops *
 nft_limit_obj_select_ops(const struct nft_ctx *ctx,
 			 const struct nlattr * const tb[])
 {
 	if (!tb[NFTA_LIMIT_TYPE])
 		return &nft_limit_obj_pkts_ops;

 	switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) {
 	case NFT_LIMIT_PKTS:
 		return &nft_limit_obj_pkts_ops;
 	case NFT_LIMIT_PKT_BYTES:
 		return &nft_limit_obj_bytes_ops;
 	}
 	return ERR_PTR(-EOPNOTSUPP);
 }

 static struct nft_object_type nft_limit_obj_type __read_mostly = {
 	.select_ops	= nft_limit_obj_select_ops,
 	.type		= NFT_OBJECT_LIMIT,
 	.maxattr	= NFTA_LIMIT_MAX,
 	.policy		= nft_limit_policy,
 	.owner		= THIS_MODULE,
 };

 static int __init nft_limit_module_init(void)
 {
 	int err;

 	err = nft_register_obj(&nft_limit_obj_type);
 	if (err < 0)
 		return err;

 	err = nft_register_expr(&nft_limit_type);
 	if (err < 0)
 		goto err1;

 	return 0;
 err1:
 	nft_unregister_obj(&nft_limit_obj_type);
 	return err;
 }

 static void __exit nft_limit_module_exit(void)
 {
 	nft_unregister_expr(&nft_limit_type);
 	nft_unregister_obj(&nft_limit_obj_type);
 }

 module_init(nft_limit_module_init);
 module_exit(nft_limit_module_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 MODULE_ALIAS_NFT_EXPR("limit");
 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_LIMIT);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
	*
	* Development of this code funded by Astaro AG (http://www.astaro.com/)
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/spinlock.h>
	#include <linux/netlink.h>
	#include <linux/netfilter.h>
	#include <linux/netfilter/nf_tables.h>
	#include <net/netfilter/nf_tables.h>

	struct nft_limit {
	spinlock_t lock;
	u64 last;
	u64 tokens;
	u64 tokens_max;
	u64 rate;
	u64 nsecs;
	u32 burst;
	bool invert;
	};

	static inline bool nft_limit_eval(struct nft_limit *limit, u64 cost)
	{
	u64 now, tokens;
	s64 delta;

	spin_lock_bh(&limit->lock);
	now = ktime_get_ns();
	tokens = limit->tokens + now - limit->last;
	if (tokens > limit->tokens_max)
	tokens = limit->tokens_max;

	limit->last = now;
	delta = tokens - cost;
	if (delta >= 0) {
	limit->tokens = delta;
	spin_unlock_bh(&limit->lock);
	return limit->invert;
	}
	limit->tokens = tokens;
	spin_unlock_bh(&limit->lock);
	return !limit->invert;
	}

	/* Use same default as in iptables. */
	#define NFT_LIMIT_PKT_BURST_DEFAULT 5

	static int nft_limit_init(struct nft_limit *limit,
	const struct nlattr * const tb[], bool pkts)
	{
	u64 unit, tokens;

	if (tb[NFTA_LIMIT_RATE] == NULL \|\|
	tb[NFTA_LIMIT_UNIT] == NULL)
	return -EINVAL;

	limit->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
	unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
	limit->nsecs = unit * NSEC_PER_SEC;
	if (limit->rate == 0 \|\| limit->nsecs < unit)
	return -EOVERFLOW;

	if (tb[NFTA_LIMIT_BURST])
	limit->burst = ntohl(nla_get_be32(tb[NFTA_LIMIT_BURST]));

	if (pkts && limit->burst == 0)
	limit->burst = NFT_LIMIT_PKT_BURST_DEFAULT;

	if (limit->rate + limit->burst < limit->rate)
	return -EOVERFLOW;

	if (pkts) {
	tokens = div_u64(limit->nsecs, limit->rate) * limit->burst;
	} else {
	/* The token bucket size limits the number of tokens can be
	* accumulated. tokens_max specifies the bucket size.
	* tokens_max = unit * (rate + burst) / rate.
	*/
	tokens = div_u64(limit->nsecs * (limit->rate + limit->burst),
	limit->rate);
	}

	limit->tokens = tokens;
	limit->tokens_max = limit->tokens;

	if (tb[NFTA_LIMIT_FLAGS]) {
	u32 flags = ntohl(nla_get_be32(tb[NFTA_LIMIT_FLAGS]));

	if (flags & NFT_LIMIT_F_INV)
	limit->invert = true;
	}
	limit->last = ktime_get_ns();
	spin_lock_init(&limit->lock);

	return 0;
	}

	static int nft_limit_dump(struct sk_buff skb, const struct nft_limit limit,
	enum nft_limit_type type)
	{
	u32 flags = limit->invert ? NFT_LIMIT_F_INV : 0;
	u64 secs = div_u64(limit->nsecs, NSEC_PER_SEC);

	if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(limit->rate),
	NFTA_LIMIT_PAD) \|\|
	nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs),
	NFTA_LIMIT_PAD) \|\|
	nla_put_be32(skb, NFTA_LIMIT_BURST, htonl(limit->burst)) \|\|
	nla_put_be32(skb, NFTA_LIMIT_TYPE, htonl(type)) \|\|
	nla_put_be32(skb, NFTA_LIMIT_FLAGS, htonl(flags)))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}

	struct nft_limit_pkts {
	struct nft_limit limit;
	u64 cost;
	};

	static void nft_limit_pkts_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	struct nft_limit_pkts *priv = nft_expr_priv(expr);

	if (nft_limit_eval(&priv->limit, priv->cost))
	regs->verdict.code = NFT_BREAK;
	}

	static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
	[NFTA_LIMIT_RATE] = { .type = NLA_U64 },
	[NFTA_LIMIT_UNIT] = { .type = NLA_U64 },
	[NFTA_LIMIT_BURST] = { .type = NLA_U32 },
	[NFTA_LIMIT_TYPE] = { .type = NLA_U32 },
	[NFTA_LIMIT_FLAGS] = { .type = NLA_U32 },
	};

	static int nft_limit_pkts_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_limit_pkts *priv = nft_expr_priv(expr);
	int err;

	err = nft_limit_init(&priv->limit, tb, true);
	if (err < 0)
	return err;

	priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate);
	return 0;
	}

	static int nft_limit_pkts_dump(struct sk_buff skb, const struct nft_expr expr)
	{
	const struct nft_limit_pkts *priv = nft_expr_priv(expr);

	return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
	}

	static struct nft_expr_type nft_limit_type;
	static const struct nft_expr_ops nft_limit_pkts_ops = {
	.type = &nft_limit_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_limit_pkts)),
	.eval = nft_limit_pkts_eval,
	.init = nft_limit_pkts_init,
	.dump = nft_limit_pkts_dump,
	};

	static void nft_limit_bytes_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	struct nft_limit *priv = nft_expr_priv(expr);
	u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate);

	if (nft_limit_eval(priv, cost))
	regs->verdict.code = NFT_BREAK;
	}

	static int nft_limit_bytes_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_limit *priv = nft_expr_priv(expr);

	return nft_limit_init(priv, tb, false);
	}

	static int nft_limit_bytes_dump(struct sk_buff *skb,
	const struct nft_expr *expr)
	{
	const struct nft_limit *priv = nft_expr_priv(expr);

	return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
	}

	static const struct nft_expr_ops nft_limit_bytes_ops = {
	.type = &nft_limit_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_limit)),
	.eval = nft_limit_bytes_eval,
	.init = nft_limit_bytes_init,
	.dump = nft_limit_bytes_dump,
	};

	static const struct nft_expr_ops *
	nft_limit_select_ops(const struct nft_ctx *ctx,
	const struct nlattr * const tb[])
	{
	if (tb[NFTA_LIMIT_TYPE] == NULL)
	return &nft_limit_pkts_ops;

	switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) {
	case NFT_LIMIT_PKTS:
	return &nft_limit_pkts_ops;
	case NFT_LIMIT_PKT_BYTES:
	return &nft_limit_bytes_ops;
	}
	return ERR_PTR(-EOPNOTSUPP);
	}

	static struct nft_expr_type nft_limit_type __read_mostly = {
	.name = "limit",
	.select_ops = nft_limit_select_ops,
	.policy = nft_limit_policy,
	.maxattr = NFTA_LIMIT_MAX,
	.flags = NFT_EXPR_STATEFUL,
	.owner = THIS_MODULE,
	};

	static void nft_limit_obj_pkts_eval(struct nft_object *obj,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	struct nft_limit_pkts *priv = nft_obj_data(obj);

	if (nft_limit_eval(&priv->limit, priv->cost))
	regs->verdict.code = NFT_BREAK;
	}

	static int nft_limit_obj_pkts_init(const struct nft_ctx *ctx,
	const struct nlattr * const tb[],
	struct nft_object *obj)
	{
	struct nft_limit_pkts *priv = nft_obj_data(obj);
	int err;

	err = nft_limit_init(&priv->limit, tb, true);
	if (err < 0)
	return err;

	priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate);
	return 0;
	}

	static int nft_limit_obj_pkts_dump(struct sk_buff *skb,
	struct nft_object *obj,
	bool reset)
	{
	const struct nft_limit_pkts *priv = nft_obj_data(obj);

	return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
	}

	static struct nft_object_type nft_limit_obj_type;
	static const struct nft_object_ops nft_limit_obj_pkts_ops = {
	.type = &nft_limit_obj_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_limit_pkts)),
	.init = nft_limit_obj_pkts_init,
	.eval = nft_limit_obj_pkts_eval,
	.dump = nft_limit_obj_pkts_dump,
	};

	static void nft_limit_obj_bytes_eval(struct nft_object *obj,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	struct nft_limit *priv = nft_obj_data(obj);
	u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate);

	if (nft_limit_eval(priv, cost))
	regs->verdict.code = NFT_BREAK;
	}

	static int nft_limit_obj_bytes_init(const struct nft_ctx *ctx,
	const struct nlattr * const tb[],
	struct nft_object *obj)
	{
	struct nft_limit *priv = nft_obj_data(obj);

	return nft_limit_init(priv, tb, false);
	}

	static int nft_limit_obj_bytes_dump(struct sk_buff *skb,
	struct nft_object *obj,
	bool reset)
	{
	const struct nft_limit *priv = nft_obj_data(obj);

	return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
	}

	static struct nft_object_type nft_limit_obj_type;
	static const struct nft_object_ops nft_limit_obj_bytes_ops = {
	.type = &nft_limit_obj_type,
	.size = sizeof(struct nft_limit),
	.init = nft_limit_obj_bytes_init,
	.eval = nft_limit_obj_bytes_eval,
	.dump = nft_limit_obj_bytes_dump,
	};

	static const struct nft_object_ops *
	nft_limit_obj_select_ops(const struct nft_ctx *ctx,
	const struct nlattr * const tb[])
	{
	if (!tb[NFTA_LIMIT_TYPE])
	return &nft_limit_obj_pkts_ops;

	switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) {
	case NFT_LIMIT_PKTS:
	return &nft_limit_obj_pkts_ops;
	case NFT_LIMIT_PKT_BYTES:
	return &nft_limit_obj_bytes_ops;
	}
	return ERR_PTR(-EOPNOTSUPP);
	}

	static struct nft_object_type nft_limit_obj_type __read_mostly = {
	.select_ops = nft_limit_obj_select_ops,
	.type = NFT_OBJECT_LIMIT,
	.maxattr = NFTA_LIMIT_MAX,
	.policy = nft_limit_policy,
	.owner = THIS_MODULE,
	};

	static int __init nft_limit_module_init(void)
	{
	int err;

	err = nft_register_obj(&nft_limit_obj_type);
	if (err < 0)
	return err;

	err = nft_register_expr(&nft_limit_type);
	if (err < 0)
	goto err1;

	return 0;
	err1:
	nft_unregister_obj(&nft_limit_obj_type);
	return err;
	}

	static void __exit nft_limit_module_exit(void)
	{
	nft_unregister_expr(&nft_limit_type);
	nft_unregister_obj(&nft_limit_obj_type);
	}

	module_init(nft_limit_module_init);
	module_exit(nft_limit_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
	MODULE_ALIAS_NFT_EXPR("limit");
	MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_LIMIT);