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

 /*
  * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
  *
  * 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.
  *
  * 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/list.h>
 #include <linux/jhash.h>
 #include <linux/netlink.h>
 #include <linux/vmalloc.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables.h>

 #define NFT_HASH_MIN_SIZE	4

 struct nft_hash {
 	struct nft_hash_table __rcu	*tbl;
 };

 struct nft_hash_table {
 	unsigned int			size;
 	unsigned int			elements;
 	struct nft_hash_elem __rcu	*buckets[];
 };

 struct nft_hash_elem {
 	struct nft_hash_elem __rcu	*next;
 	struct nft_data			key;
 	struct nft_data			data[];
 };

 #define nft_hash_for_each_entry(i, head) \
 	for (i = nft_dereference(head); i != NULL; i = nft_dereference(i->next))
 #define nft_hash_for_each_entry_rcu(i, head) \
 	for (i = rcu_dereference(head); i != NULL; i = rcu_dereference(i->next))

 static u32 nft_hash_rnd __read_mostly;
 static bool nft_hash_rnd_initted __read_mostly;

 static unsigned int nft_hash_data(const struct nft_data *data,
 				  unsigned int hsize, unsigned int len)
 {
 	unsigned int h;

 	h = jhash(data->data, len, nft_hash_rnd);
 	return h & (hsize - 1);
 }

 static bool nft_hash_lookup(const struct nft_set *set,
 			    const struct nft_data *key,
 			    struct nft_data *data)
 {
 	const struct nft_hash *priv = nft_set_priv(set);
 	const struct nft_hash_table *tbl = rcu_dereference(priv->tbl);
 	const struct nft_hash_elem *he;
 	unsigned int h;

 	h = nft_hash_data(key, tbl->size, set->klen);
 	nft_hash_for_each_entry_rcu(he, tbl->buckets[h]) {
 		if (nft_data_cmp(&he->key, key, set->klen))
 			continue;
 		if (set->flags & NFT_SET_MAP)
 			nft_data_copy(data, he->data);
 		return true;
 	}
 	return false;
 }

 static void nft_hash_tbl_free(const struct nft_hash_table *tbl)
 {
 	if (is_vmalloc_addr(tbl))
 		vfree(tbl);
 	else
 		kfree(tbl);
 }

 static struct nft_hash_table *nft_hash_tbl_alloc(unsigned int nbuckets)
 {
 	struct nft_hash_table *tbl;
 	size_t size;

 	size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
 	tbl = kzalloc(size, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN);
 	if (tbl == NULL)
 		tbl = vzalloc(size);
 	if (tbl == NULL)
 		return NULL;
 	tbl->size = nbuckets;

 	return tbl;
 }

 static void nft_hash_chain_unzip(const struct nft_set *set,
 				 const struct nft_hash_table *ntbl,
 				 struct nft_hash_table *tbl, unsigned int n)
 {
 	struct nft_hash_elem *he, *last, *next;
 	unsigned int h;

 	he = nft_dereference(tbl->buckets[n]);
 	if (he == NULL)
 		return;
 	h = nft_hash_data(&he->key, ntbl->size, set->klen);

 	/* Find last element of first chain hashing to bucket h */
 	last = he;
 	nft_hash_for_each_entry(he, he->next) {
 		if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
 			break;
 		last = he;
 	}

 	/* Unlink first chain from the old table */
 	RCU_INIT_POINTER(tbl->buckets[n], last->next);

 	/* If end of chain reached, done */
 	if (he == NULL)
 		return;

 	/* Find first element of second chain hashing to bucket h */
 	next = NULL;
 	nft_hash_for_each_entry(he, he->next) {
 		if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
 			continue;
 		next = he;
 		break;
 	}

 	/* Link the two chains */
 	RCU_INIT_POINTER(last->next, next);
 }

 static int nft_hash_tbl_expand(const struct nft_set *set, struct nft_hash *priv)
 {
 	struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
 	struct nft_hash_elem *he;
 	unsigned int i, h;
 	bool complete;

 	ntbl = nft_hash_tbl_alloc(tbl->size * 2);
 	if (ntbl == NULL)
 		return -ENOMEM;

 	/* Link new table's buckets to first element in the old table
 	 * hashing to the new bucket.
 	 */
 	for (i = 0; i < ntbl->size; i++) {
 		h = i < tbl->size ? i : i - tbl->size;
 		nft_hash_for_each_entry(he, tbl->buckets[h]) {
 			if (nft_hash_data(&he->key, ntbl->size, set->klen) != i)
 				continue;
 			RCU_INIT_POINTER(ntbl->buckets[i], he);
 			break;
 		}
 	}
 	ntbl->elements = tbl->elements;

 	/* Publish new table */
 	rcu_assign_pointer(priv->tbl, ntbl);

 	/* Unzip interleaved hash chains */
 	do {
 		/* Wait for readers to use new table/unzipped chains */
 		synchronize_rcu();

 		complete = true;
 		for (i = 0; i < tbl->size; i++) {
 			nft_hash_chain_unzip(set, ntbl, tbl, i);
 			if (tbl->buckets[i] != NULL)
 				complete = false;
 		}
 	} while (!complete);

 	nft_hash_tbl_free(tbl);
 	return 0;
 }

 static int nft_hash_tbl_shrink(const struct nft_set *set, struct nft_hash *priv)
 {
 	struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
 	struct nft_hash_elem __rcu **pprev;
 	unsigned int i;

 	ntbl = nft_hash_tbl_alloc(tbl->size / 2);
 	if (ntbl == NULL)
 		return -ENOMEM;

 	for (i = 0; i < ntbl->size; i++) {
 		ntbl->buckets[i] = tbl->buckets[i];

 		for (pprev = &ntbl->buckets[i]; *pprev != NULL;
 		     pprev = &nft_dereference(*pprev)->next)
 			;
 		RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
 	}
 	ntbl->elements = tbl->elements;

 	/* Publish new table */
 	rcu_assign_pointer(priv->tbl, ntbl);
 	synchronize_rcu();

 	nft_hash_tbl_free(tbl);
 	return 0;
 }

 static int nft_hash_insert(const struct nft_set *set,
 			   const struct nft_set_elem *elem)
 {
 	struct nft_hash *priv = nft_set_priv(set);
 	struct nft_hash_table *tbl = nft_dereference(priv->tbl);
 	struct nft_hash_elem *he;
 	unsigned int size, h;

 	if (elem->flags != 0)
 		return -EINVAL;

 	size = sizeof(*he);
 	if (set->flags & NFT_SET_MAP)
 		size += sizeof(he->data[0]);

 	he = kzalloc(size, GFP_KERNEL);
 	if (he == NULL)
 		return -ENOMEM;

 	nft_data_copy(&he->key, &elem->key);
 	if (set->flags & NFT_SET_MAP)
 		nft_data_copy(he->data, &elem->data);

 	h = nft_hash_data(&he->key, tbl->size, set->klen);
 	RCU_INIT_POINTER(he->next, tbl->buckets[h]);
 	rcu_assign_pointer(tbl->buckets[h], he);
 	tbl->elements++;

 	/* Expand table when exceeding 75% load */
 	if (tbl->elements > tbl->size / 4 * 3)
 		nft_hash_tbl_expand(set, priv);

 	return 0;
 }

 static void nft_hash_elem_destroy(const struct nft_set *set,
 				  struct nft_hash_elem *he)
 {
 	nft_data_uninit(&he->key, NFT_DATA_VALUE);
 	if (set->flags & NFT_SET_MAP)
 		nft_data_uninit(he->data, set->dtype);
 	kfree(he);
 }

 static void nft_hash_remove(const struct nft_set *set,
 			    const struct nft_set_elem *elem)
 {
 	struct nft_hash *priv = nft_set_priv(set);
 	struct nft_hash_table *tbl = nft_dereference(priv->tbl);
 	struct nft_hash_elem *he, __rcu **pprev;

 	pprev = elem->cookie;
 	he = nft_dereference((*pprev));

 	RCU_INIT_POINTER(*pprev, he->next);
 	synchronize_rcu();
 	kfree(he);
 	tbl->elements--;

 	/* Shrink table beneath 30% load */
 	if (tbl->elements < tbl->size * 3 / 10 &&
 	    tbl->size > NFT_HASH_MIN_SIZE)
 		nft_hash_tbl_shrink(set, priv);
 }

 static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem)
 {
 	const struct nft_hash *priv = nft_set_priv(set);
 	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
 	struct nft_hash_elem __rcu * const *pprev;
 	struct nft_hash_elem *he;
 	unsigned int h;

 	h = nft_hash_data(&elem->key, tbl->size, set->klen);
 	pprev = &tbl->buckets[h];
 	nft_hash_for_each_entry(he, tbl->buckets[h]) {
 		if (nft_data_cmp(&he->key, &elem->key, set->klen)) {
 			pprev = &he->next;
 			continue;
 		}

 		elem->cookie = (void *)pprev;
 		elem->flags = 0;
 		if (set->flags & NFT_SET_MAP)
 			nft_data_copy(&elem->data, he->data);
 		return 0;
 	}
 	return -ENOENT;
 }

 static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
 			  struct nft_set_iter *iter)
 {
 	const struct nft_hash *priv = nft_set_priv(set);
 	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
 	const struct nft_hash_elem *he;
 	struct nft_set_elem elem;
 	unsigned int i;

 	for (i = 0; i < tbl->size; i++) {
 		nft_hash_for_each_entry(he, tbl->buckets[i]) {
 			if (iter->count < iter->skip)
 				goto cont;

 			memcpy(&elem.key, &he->key, sizeof(elem.key));
 			if (set->flags & NFT_SET_MAP)
 				memcpy(&elem.data, he->data, sizeof(elem.data));
 			elem.flags = 0;

 			iter->err = iter->fn(ctx, set, iter, &elem);
 			if (iter->err < 0)
 				return;
 cont:
 			iter->count++;
 		}
 	}
 }

 static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
 {
 	return sizeof(struct nft_hash);
 }

 static int nft_hash_init(const struct nft_set *set,
 			 const struct nlattr * const tb[])
 {
 	struct nft_hash *priv = nft_set_priv(set);
 	struct nft_hash_table *tbl;

 	if (unlikely(!nft_hash_rnd_initted)) {
 		get_random_bytes(&nft_hash_rnd, 4);
 		nft_hash_rnd_initted = true;
 	}

 	tbl = nft_hash_tbl_alloc(NFT_HASH_MIN_SIZE);
 	if (tbl == NULL)
 		return -ENOMEM;
 	RCU_INIT_POINTER(priv->tbl, tbl);
 	return 0;
 }

 static void nft_hash_destroy(const struct nft_set *set)
 {
 	const struct nft_hash *priv = nft_set_priv(set);
 	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
 	struct nft_hash_elem *he, *next;
 	unsigned int i;

 	for (i = 0; i < tbl->size; i++) {
 		for (he = nft_dereference(tbl->buckets[i]); he != NULL;
 		     he = next) {
 			next = nft_dereference(he->next);
 			nft_hash_elem_destroy(set, he);
 		}
 	}
 	kfree(tbl);
 }

 static struct nft_set_ops nft_hash_ops __read_mostly = {
 	.privsize       = nft_hash_privsize,
 	.init		= nft_hash_init,
 	.destroy	= nft_hash_destroy,
 	.get		= nft_hash_get,
 	.insert		= nft_hash_insert,
 	.remove		= nft_hash_remove,
 	.lookup		= nft_hash_lookup,
 	.walk		= nft_hash_walk,
 	.features	= NFT_SET_MAP,
 	.owner		= THIS_MODULE,
 };

 static int __init nft_hash_module_init(void)
 {
 	return nft_register_set(&nft_hash_ops);
 }

 static void __exit nft_hash_module_exit(void)
 {
 	nft_unregister_set(&nft_hash_ops);
 }

 module_init(nft_hash_module_init);
 module_exit(nft_hash_module_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 MODULE_ALIAS_NFT_SET();
	/*
	* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
	*
	* 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.
	*
	* 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/list.h>
	#include <linux/jhash.h>
	#include <linux/netlink.h>
	#include <linux/vmalloc.h>
	#include <linux/netfilter.h>
	#include <linux/netfilter/nf_tables.h>
	#include <net/netfilter/nf_tables.h>

	#define NFT_HASH_MIN_SIZE 4

	struct nft_hash {
	struct nft_hash_table __rcu *tbl;
	};

	struct nft_hash_table {
	unsigned int size;
	unsigned int elements;
	struct nft_hash_elem __rcu *buckets[];
	};

	struct nft_hash_elem {
	struct nft_hash_elem __rcu *next;
	struct nft_data key;
	struct nft_data data[];
	};

	#define nft_hash_for_each_entry(i, head) \
	for (i = nft_dereference(head); i != NULL; i = nft_dereference(i->next))
	#define nft_hash_for_each_entry_rcu(i, head) \
	for (i = rcu_dereference(head); i != NULL; i = rcu_dereference(i->next))

	static u32 nft_hash_rnd __read_mostly;
	static bool nft_hash_rnd_initted __read_mostly;

	static unsigned int nft_hash_data(const struct nft_data *data,
	unsigned int hsize, unsigned int len)
	{
	unsigned int h;

	h = jhash(data->data, len, nft_hash_rnd);
	return h & (hsize - 1);
	}

	static bool nft_hash_lookup(const struct nft_set *set,
	const struct nft_data *key,
	struct nft_data *data)
	{
	const struct nft_hash *priv = nft_set_priv(set);
	const struct nft_hash_table *tbl = rcu_dereference(priv->tbl);
	const struct nft_hash_elem *he;
	unsigned int h;

	h = nft_hash_data(key, tbl->size, set->klen);
	nft_hash_for_each_entry_rcu(he, tbl->buckets[h]) {
	if (nft_data_cmp(&he->key, key, set->klen))
	continue;
	if (set->flags & NFT_SET_MAP)
	nft_data_copy(data, he->data);
	return true;
	}
	return false;
	}

	static void nft_hash_tbl_free(const struct nft_hash_table *tbl)
	{
	if (is_vmalloc_addr(tbl))
	vfree(tbl);
	else
	kfree(tbl);
	}

	static struct nft_hash_table *nft_hash_tbl_alloc(unsigned int nbuckets)
	{
	struct nft_hash_table *tbl;
	size_t size;

	size = sizeof(tbl) + nbuckets sizeof(tbl->buckets[0]);
	tbl = kzalloc(size, GFP_KERNEL \| __GFP_REPEAT \| __GFP_NOWARN);
	if (tbl == NULL)
	tbl = vzalloc(size);
	if (tbl == NULL)
	return NULL;
	tbl->size = nbuckets;

	return tbl;
	}

	static void nft_hash_chain_unzip(const struct nft_set *set,
	const struct nft_hash_table *ntbl,
	struct nft_hash_table *tbl, unsigned int n)
	{
	struct nft_hash_elem he, last, *next;
	unsigned int h;

	he = nft_dereference(tbl->buckets[n]);
	if (he == NULL)
	return;
	h = nft_hash_data(&he->key, ntbl->size, set->klen);

	/* Find last element of first chain hashing to bucket h */
	last = he;
	nft_hash_for_each_entry(he, he->next) {
	if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
	break;
	last = he;
	}

	/* Unlink first chain from the old table */
	RCU_INIT_POINTER(tbl->buckets[n], last->next);

	/* If end of chain reached, done */
	if (he == NULL)
	return;

	/* Find first element of second chain hashing to bucket h */
	next = NULL;
	nft_hash_for_each_entry(he, he->next) {
	if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
	continue;
	next = he;
	break;
	}

	/* Link the two chains */
	RCU_INIT_POINTER(last->next, next);
	}

	static int nft_hash_tbl_expand(const struct nft_set set, struct nft_hash priv)
	{
	struct nft_hash_table tbl = nft_dereference(priv->tbl), ntbl;
	struct nft_hash_elem *he;
	unsigned int i, h;
	bool complete;

	ntbl = nft_hash_tbl_alloc(tbl->size * 2);
	if (ntbl == NULL)
	return -ENOMEM;

	/* Link new table's buckets to first element in the old table
	* hashing to the new bucket.
	*/
	for (i = 0; i < ntbl->size; i++) {
	h = i < tbl->size ? i : i - tbl->size;
	nft_hash_for_each_entry(he, tbl->buckets[h]) {
	if (nft_hash_data(&he->key, ntbl->size, set->klen) != i)
	continue;
	RCU_INIT_POINTER(ntbl->buckets[i], he);
	break;
	}
	}
	ntbl->elements = tbl->elements;

	/* Publish new table */
	rcu_assign_pointer(priv->tbl, ntbl);

	/* Unzip interleaved hash chains */
	do {
	/* Wait for readers to use new table/unzipped chains */
	synchronize_rcu();

	complete = true;
	for (i = 0; i < tbl->size; i++) {
	nft_hash_chain_unzip(set, ntbl, tbl, i);
	if (tbl->buckets[i] != NULL)
	complete = false;
	}
	} while (!complete);

	nft_hash_tbl_free(tbl);
	return 0;
	}

	static int nft_hash_tbl_shrink(const struct nft_set set, struct nft_hash priv)
	{
	struct nft_hash_table tbl = nft_dereference(priv->tbl), ntbl;
	struct nft_hash_elem __rcu **pprev;
	unsigned int i;

	ntbl = nft_hash_tbl_alloc(tbl->size / 2);
	if (ntbl == NULL)
	return -ENOMEM;

	for (i = 0; i < ntbl->size; i++) {
	ntbl->buckets[i] = tbl->buckets[i];

	for (pprev = &ntbl->buckets[i]; *pprev != NULL;
	pprev = &nft_dereference(*pprev)->next)
	;
	RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
	}
	ntbl->elements = tbl->elements;

	/* Publish new table */
	rcu_assign_pointer(priv->tbl, ntbl);
	synchronize_rcu();

	nft_hash_tbl_free(tbl);
	return 0;
	}

	static int nft_hash_insert(const struct nft_set *set,
	const struct nft_set_elem *elem)
	{
	struct nft_hash *priv = nft_set_priv(set);
	struct nft_hash_table *tbl = nft_dereference(priv->tbl);
	struct nft_hash_elem *he;
	unsigned int size, h;

	if (elem->flags != 0)
	return -EINVAL;

	size = sizeof(*he);
	if (set->flags & NFT_SET_MAP)
	size += sizeof(he->data[0]);

	he = kzalloc(size, GFP_KERNEL);
	if (he == NULL)
	return -ENOMEM;

	nft_data_copy(&he->key, &elem->key);
	if (set->flags & NFT_SET_MAP)
	nft_data_copy(he->data, &elem->data);

	h = nft_hash_data(&he->key, tbl->size, set->klen);
	RCU_INIT_POINTER(he->next, tbl->buckets[h]);
	rcu_assign_pointer(tbl->buckets[h], he);
	tbl->elements++;

	/* Expand table when exceeding 75% load */
	if (tbl->elements > tbl->size / 4 * 3)
	nft_hash_tbl_expand(set, priv);

	return 0;
	}

	static void nft_hash_elem_destroy(const struct nft_set *set,
	struct nft_hash_elem *he)
	{
	nft_data_uninit(&he->key, NFT_DATA_VALUE);
	if (set->flags & NFT_SET_MAP)
	nft_data_uninit(he->data, set->dtype);
	kfree(he);
	}

	static void nft_hash_remove(const struct nft_set *set,
	const struct nft_set_elem *elem)
	{
	struct nft_hash *priv = nft_set_priv(set);
	struct nft_hash_table *tbl = nft_dereference(priv->tbl);
	struct nft_hash_elem he, __rcu *pprev;

	pprev = elem->cookie;
	he = nft_dereference((*pprev));

	RCU_INIT_POINTER(*pprev, he->next);
	synchronize_rcu();
	kfree(he);
	tbl->elements--;

	/* Shrink table beneath 30% load */
	if (tbl->elements < tbl->size * 3 / 10 &&
	tbl->size > NFT_HASH_MIN_SIZE)
	nft_hash_tbl_shrink(set, priv);
	}

	static int nft_hash_get(const struct nft_set set, struct nft_set_elem elem)
	{
	const struct nft_hash *priv = nft_set_priv(set);
	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
	struct nft_hash_elem __rcu * const *pprev;
	struct nft_hash_elem *he;
	unsigned int h;

	h = nft_hash_data(&elem->key, tbl->size, set->klen);
	pprev = &tbl->buckets[h];
	nft_hash_for_each_entry(he, tbl->buckets[h]) {
	if (nft_data_cmp(&he->key, &elem->key, set->klen)) {
	pprev = &he->next;
	continue;
	}

	elem->cookie = (void *)pprev;
	elem->flags = 0;
	if (set->flags & NFT_SET_MAP)
	nft_data_copy(&elem->data, he->data);
	return 0;
	}
	return -ENOENT;
	}

	static void nft_hash_walk(const struct nft_ctx ctx, const struct nft_set set,
	struct nft_set_iter *iter)
	{
	const struct nft_hash *priv = nft_set_priv(set);
	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
	const struct nft_hash_elem *he;
	struct nft_set_elem elem;
	unsigned int i;

	for (i = 0; i < tbl->size; i++) {
	nft_hash_for_each_entry(he, tbl->buckets[i]) {
	if (iter->count < iter->skip)
	goto cont;

	memcpy(&elem.key, &he->key, sizeof(elem.key));
	if (set->flags & NFT_SET_MAP)
	memcpy(&elem.data, he->data, sizeof(elem.data));
	elem.flags = 0;

	iter->err = iter->fn(ctx, set, iter, &elem);
	if (iter->err < 0)
	return;
	cont:
	iter->count++;
	}
	}
	}

	static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
	{
	return sizeof(struct nft_hash);
	}

	static int nft_hash_init(const struct nft_set *set,
	const struct nlattr * const tb[])
	{
	struct nft_hash *priv = nft_set_priv(set);
	struct nft_hash_table *tbl;

	if (unlikely(!nft_hash_rnd_initted)) {
	get_random_bytes(&nft_hash_rnd, 4);
	nft_hash_rnd_initted = true;
	}

	tbl = nft_hash_tbl_alloc(NFT_HASH_MIN_SIZE);
	if (tbl == NULL)
	return -ENOMEM;
	RCU_INIT_POINTER(priv->tbl, tbl);
	return 0;
	}

	static void nft_hash_destroy(const struct nft_set *set)
	{
	const struct nft_hash *priv = nft_set_priv(set);
	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
	struct nft_hash_elem he, next;
	unsigned int i;

	for (i = 0; i < tbl->size; i++) {
	for (he = nft_dereference(tbl->buckets[i]); he != NULL;
	he = next) {
	next = nft_dereference(he->next);
	nft_hash_elem_destroy(set, he);
	}
	}
	kfree(tbl);
	}

	static struct nft_set_ops nft_hash_ops __read_mostly = {
	.privsize = nft_hash_privsize,
	.init = nft_hash_init,
	.destroy = nft_hash_destroy,
	.get = nft_hash_get,
	.insert = nft_hash_insert,
	.remove = nft_hash_remove,
	.lookup = nft_hash_lookup,
	.walk = nft_hash_walk,
	.features = NFT_SET_MAP,
	.owner = THIS_MODULE,
	};

	static int __init nft_hash_module_init(void)
	{
	return nft_register_set(&nft_hash_ops);
	}

	static void __exit nft_hash_module_exit(void)
	{
	nft_unregister_set(&nft_hash_ops);
	}

	module_init(nft_hash_module_init);
	module_exit(nft_hash_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
	MODULE_ALIAS_NFT_SET();