[deliverable/linux.git] / net / netfilter / nft_hash.c

/*
 * 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/log2.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	4UL

struct nft_hash {
	struct nft_hash_table __rcu	*tbl;
};

struct nft_hash_table {
	unsigned int			size;
	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)
{
	kvfree(tbl);
}

static unsigned int nft_hash_tbl_size(unsigned int nelem)
{
	return max(roundup_pow_of_two(nelem * 4 / 3), NFT_HASH_MIN_SIZE);
}

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;
		}
	}

	/* 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]);
	}

	/* 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);

	/* Expand table when exceeding 75% load */
	if (set->nelems + 1 > 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);

	/* Shrink table beneath 30% load */
	if (set->nelems - 1 < 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 nft_set_desc *desc,
			 const struct nlattr * const tb[])
{
	struct nft_hash *priv = nft_set_priv(set);
	struct nft_hash_table *tbl;
	unsigned int size;

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

	size = NFT_HASH_MIN_SIZE;
	if (desc->size)
		size = nft_hash_tbl_size(desc->size);

	tbl = nft_hash_tbl_alloc(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 bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
			      struct nft_set_estimate *est)
{
	unsigned int esize;

	esize = sizeof(struct nft_hash_elem);
	if (features & NFT_SET_MAP)
		esize += FIELD_SIZEOF(struct nft_hash_elem, data[0]);

	if (desc->size) {
		est->size = sizeof(struct nft_hash) +
			    nft_hash_tbl_size(desc->size) *
			    sizeof(struct nft_hash_elem *) +
			    desc->size * esize;
	} else {
		/* Resizing happens when the load drops below 30% or goes
		 * above 75%. The average of 52.5% load (approximated by 50%)
		 * is used for the size estimation of the hash buckets,
		 * meaning we calculate two buckets per element.
		 */
		est->size = esize + 2 * sizeof(struct nft_hash_elem *);
	}

	est->class = NFT_SET_CLASS_O_1;

	return true;
}

static struct nft_set_ops nft_hash_ops __read_mostly = {
	.privsize       = nft_hash_privsize,
	.estimate	= nft_hash_estimate,
	.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();
Commit	Line	Data
96518518	1	/*
ce6eb0d7	2	* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
96518518 PM	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* Development of this code funded by Astaro AG (http://www.astaro.com/)
	9	*/
	10
	11	#include <linux/kernel.h>
	12	#include <linux/init.h>
	13	#include <linux/module.h>
	14	#include <linux/list.h>
c50b960c	15	#include <linux/log2.h>
96518518 PM	16	#include <linux/jhash.h>
96518518 PM	17	#include <linux/netlink.h>
3ab428a4	18	#include <linux/vmalloc.h>
96518518 PM	19	#include <linux/netfilter.h>
	20	#include <linux/netfilter/nf_tables.h>
	21	#include <net/netfilter/nf_tables.h>
	22
c50b960c	23	#define NFT_HASH_MIN_SIZE 4UL
ce6eb0d7	24
96518518	25	struct nft_hash {
ce6eb0d7 PM	26	struct nft_hash_table __rcu *tbl;
	27	};
	28
	29	struct nft_hash_table {
	30	unsigned int size;
ce6eb0d7	31	struct nft_hash_elem __rcu *buckets[];
96518518 PM	32	};
	33
	34	struct nft_hash_elem {
ce6eb0d7 PM	35	struct nft_hash_elem __rcu *next;
	36	struct nft_data key;
	37	struct nft_data data[];
96518518 PM	38	};
96518518 PM	39
ce6eb0d7 PM	40	#define nft_hash_for_each_entry(i, head) \
	41	for (i = nft_dereference(head); i != NULL; i = nft_dereference(i->next))
	42	#define nft_hash_for_each_entry_rcu(i, head) \
	43	for (i = rcu_dereference(head); i != NULL; i = rcu_dereference(i->next))
	44
96518518 PM	45	static u32 nft_hash_rnd __read_mostly;
	46	static bool nft_hash_rnd_initted __read_mostly;
	47
	48	static unsigned int nft_hash_data(const struct nft_data *data,
	49	unsigned int hsize, unsigned int len)
	50	{
	51	unsigned int h;
	52
20a69341	53	h = jhash(data->data, len, nft_hash_rnd);
ce6eb0d7	54	return h & (hsize - 1);
96518518 PM	55	}
96518518 PM	56
20a69341 PM	57	static bool nft_hash_lookup(const struct nft_set *set,
	58	const struct nft_data *key,
	59	struct nft_data *data)
96518518	60	{
20a69341	61	const struct nft_hash *priv = nft_set_priv(set);
ce6eb0d7	62	const struct nft_hash_table *tbl = rcu_dereference(priv->tbl);
20a69341	63	const struct nft_hash_elem *he;
96518518 PM	64	unsigned int h;
96518518 PM	65
ce6eb0d7 PM	66	h = nft_hash_data(key, tbl->size, set->klen);
ce6eb0d7 PM	67	nft_hash_for_each_entry_rcu(he, tbl->buckets[h]) {
20a69341	68	if (nft_data_cmp(&he->key, key, set->klen))
96518518	69	continue;
20a69341 PM	70	if (set->flags & NFT_SET_MAP)
	71	nft_data_copy(data, he->data);
	72	return true;
96518518	73	}
20a69341	74	return false;
96518518 PM	75	}
96518518 PM	76
ce6eb0d7	77	static void nft_hash_tbl_free(const struct nft_hash_table *tbl)
96518518	78	{
4cb28970	79	kvfree(tbl);
ce6eb0d7 PM	80	}
ce6eb0d7 PM	81
c50b960c PM	82	static unsigned int nft_hash_tbl_size(unsigned int nelem)
	83	{
	84	return max(roundup_pow_of_two(nelem * 4 / 3), NFT_HASH_MIN_SIZE);
	85	}
	86
ce6eb0d7 PM	87	static struct nft_hash_table *nft_hash_tbl_alloc(unsigned int nbuckets)
	88	{
	89	struct nft_hash_table *tbl;
	90	size_t size;
	91
	92	size = sizeof(tbl) + nbuckets sizeof(tbl->buckets[0]);
	93	tbl = kzalloc(size, GFP_KERNEL \| __GFP_REPEAT \| __GFP_NOWARN);
	94	if (tbl == NULL)
	95	tbl = vzalloc(size);
	96	if (tbl == NULL)
	97	return NULL;
	98	tbl->size = nbuckets;
	99
	100	return tbl;
	101	}
	102
	103	static void nft_hash_chain_unzip(const struct nft_set *set,
	104	const struct nft_hash_table *ntbl,
	105	struct nft_hash_table *tbl, unsigned int n)
	106	{
	107	struct nft_hash_elem he, last, *next;
	108	unsigned int h;
	109
	110	he = nft_dereference(tbl->buckets[n]);
	111	if (he == NULL)
	112	return;
	113	h = nft_hash_data(&he->key, ntbl->size, set->klen);
	114
	115	/* Find last element of first chain hashing to bucket h */
	116	last = he;
	117	nft_hash_for_each_entry(he, he->next) {
	118	if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
	119	break;
	120	last = he;
	121	}
	122
	123	/* Unlink first chain from the old table */
	124	RCU_INIT_POINTER(tbl->buckets[n], last->next);
	125
	126	/* If end of chain reached, done */
	127	if (he == NULL)
	128	return;
	129
	130	/* Find first element of second chain hashing to bucket h */
	131	next = NULL;
	132	nft_hash_for_each_entry(he, he->next) {
	133	if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
	134	continue;
	135	next = he;
	136	break;
	137	}
	138
	139	/* Link the two chains */
	140	RCU_INIT_POINTER(last->next, next);
	141	}
	142
	143	static int nft_hash_tbl_expand(const struct nft_set set, struct nft_hash priv)
	144	{
	145	struct nft_hash_table tbl = nft_dereference(priv->tbl), ntbl;
	146	struct nft_hash_elem *he;
	147	unsigned int i, h;
	148	bool complete;
	149
	150	ntbl = nft_hash_tbl_alloc(tbl->size * 2);
151	if (ntbl == NULL)
152	return -ENOMEM;
153
154	/* Link new table's buckets to first element in the old table
155	* hashing to the new bucket.
156	*/
157	for (i = 0; i < ntbl->size; i++) {
158	h = i < tbl->size ? i : i - tbl->size;
159	nft_hash_for_each_entry(he, tbl->buckets[h]) {
160	if (nft_hash_data(&he->key, ntbl->size, set->klen) != i)
161	continue;
162	RCU_INIT_POINTER(ntbl->buckets[i], he);
163	break;
164	}
165	}
ce6eb0d7 PM	166
	167	/* Publish new table */
	168	rcu_assign_pointer(priv->tbl, ntbl);
	169
	170	/* Unzip interleaved hash chains */
	171	do {
	172	/* Wait for readers to use new table/unzipped chains */
	173	synchronize_rcu();
	174
	175	complete = true;
	176	for (i = 0; i < tbl->size; i++) {
	177	nft_hash_chain_unzip(set, ntbl, tbl, i);
	178	if (tbl->buckets[i] != NULL)
	179	complete = false;
	180	}
	181	} while (!complete);
	182
	183	nft_hash_tbl_free(tbl);
	184	return 0;
	185	}
	186
	187	static int nft_hash_tbl_shrink(const struct nft_set set, struct nft_hash priv)
	188	{
	189	struct nft_hash_table tbl = nft_dereference(priv->tbl), ntbl;
	190	struct nft_hash_elem __rcu **pprev;
	191	unsigned int i;
	192
	193	ntbl = nft_hash_tbl_alloc(tbl->size / 2);
	194	if (ntbl == NULL)
	195	return -ENOMEM;
	196
	197	for (i = 0; i < ntbl->size; i++) {
	198	ntbl->buckets[i] = tbl->buckets[i];
	199
	200	for (pprev = &ntbl->buckets[i]; *pprev != NULL;
	201	pprev = &nft_dereference(*pprev)->next)
	202	;
	203	RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
	204	}
ce6eb0d7 PM	205
	206	/* Publish new table */
	207	rcu_assign_pointer(priv->tbl, ntbl);
	208	synchronize_rcu();
	209
	210	nft_hash_tbl_free(tbl);
	211	return 0;
96518518 PM	212	}
96518518 PM	213
20a69341 PM	214	static int nft_hash_insert(const struct nft_set *set,
20a69341 PM	215	const struct nft_set_elem *elem)
96518518	216	{
20a69341	217	struct nft_hash *priv = nft_set_priv(set);
ce6eb0d7	218	struct nft_hash_table *tbl = nft_dereference(priv->tbl);
20a69341 PM	219	struct nft_hash_elem *he;
20a69341 PM	220	unsigned int size, h;
96518518	221
20a69341	222	if (elem->flags != 0)
96518518	223	return -EINVAL;
96518518	224
20a69341 PM	225	size = sizeof(*he);
	226	if (set->flags & NFT_SET_MAP)
	227	size += sizeof(he->data[0]);
	228
	229	he = kzalloc(size, GFP_KERNEL);
	230	if (he == NULL)
96518518 PM	231	return -ENOMEM;
96518518 PM	232
20a69341 PM	233	nft_data_copy(&he->key, &elem->key);
	234	if (set->flags & NFT_SET_MAP)
	235	nft_data_copy(he->data, &elem->data);
96518518	236
ce6eb0d7 PM	237	h = nft_hash_data(&he->key, tbl->size, set->klen);
	238	RCU_INIT_POINTER(he->next, tbl->buckets[h]);
	239	rcu_assign_pointer(tbl->buckets[h], he);
ce6eb0d7 PM	240
ce6eb0d7 PM	241	/* Expand table when exceeding 75% load */
2c96c25d	242	if (set->nelems + 1 > tbl->size / 4 * 3)
ce6eb0d7 PM	243	nft_hash_tbl_expand(set, priv);
ce6eb0d7 PM	244
96518518	245	return 0;
96518518 PM	246	}
96518518 PM	247
ce6eb0d7 PM	248	static void nft_hash_elem_destroy(const struct nft_set *set,
	249	struct nft_hash_elem *he)
	250	{
	251	nft_data_uninit(&he->key, NFT_DATA_VALUE);
	252	if (set->flags & NFT_SET_MAP)
	253	nft_data_uninit(he->data, set->dtype);
	254	kfree(he);
	255	}
	256
20a69341 PM	257	static void nft_hash_remove(const struct nft_set *set,
20a69341 PM	258	const struct nft_set_elem *elem)
96518518	259	{
ce6eb0d7 PM	260	struct nft_hash *priv = nft_set_priv(set);
	261	struct nft_hash_table *tbl = nft_dereference(priv->tbl);
	262	struct nft_hash_elem he, __rcu *pprev;
96518518	263
ce6eb0d7 PM	264	pprev = elem->cookie;
	265	he = nft_dereference((*pprev));
	266
	267	RCU_INIT_POINTER(*pprev, he->next);
	268	synchronize_rcu();
20a69341	269	kfree(he);
ce6eb0d7 PM	270
ce6eb0d7 PM	271	/* Shrink table beneath 30% load */
2c96c25d	272	if (set->nelems - 1 < tbl->size * 3 / 10 &&
ce6eb0d7 PM	273	tbl->size > NFT_HASH_MIN_SIZE)
ce6eb0d7 PM	274	nft_hash_tbl_shrink(set, priv);
20a69341	275	}
96518518	276
20a69341 PM	277	static int nft_hash_get(const struct nft_set set, struct nft_set_elem elem)
	278	{
	279	const struct nft_hash *priv = nft_set_priv(set);
ce6eb0d7 PM	280	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
ce6eb0d7 PM	281	struct nft_hash_elem __rcu * const *pprev;
20a69341 PM	282	struct nft_hash_elem *he;
20a69341 PM	283	unsigned int h;
96518518	284
ce6eb0d7 PM	285	h = nft_hash_data(&elem->key, tbl->size, set->klen);
	286	pprev = &tbl->buckets[h];
	287	nft_hash_for_each_entry(he, tbl->buckets[h]) {
	288	if (nft_data_cmp(&he->key, &elem->key, set->klen)) {
	289	pprev = &he->next;
20a69341	290	continue;
ce6eb0d7	291	}
96518518	292
ce6eb0d7 PM	293	elem->cookie = (void *)pprev;
ce6eb0d7 PM	294	elem->flags = 0;
20a69341 PM	295	if (set->flags & NFT_SET_MAP)
	296	nft_data_copy(&elem->data, he->data);
	297	return 0;
	298	}
	299	return -ENOENT;
96518518 PM	300	}
96518518 PM	301
20a69341 PM	302	static void nft_hash_walk(const struct nft_ctx ctx, const struct nft_set set,
20a69341 PM	303	struct nft_set_iter *iter)
96518518	304	{
20a69341	305	const struct nft_hash *priv = nft_set_priv(set);
ce6eb0d7	306	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
20a69341 PM	307	const struct nft_hash_elem *he;
20a69341 PM	308	struct nft_set_elem elem;
96518518 PM	309	unsigned int i;
96518518 PM	310
ce6eb0d7 PM	311	for (i = 0; i < tbl->size; i++) {
ce6eb0d7 PM	312	nft_hash_for_each_entry(he, tbl->buckets[i]) {
20a69341 PM	313	if (iter->count < iter->skip)
	314	goto cont;
	315
	316	memcpy(&elem.key, &he->key, sizeof(elem.key));
	317	if (set->flags & NFT_SET_MAP)
	318	memcpy(&elem.data, he->data, sizeof(elem.data));
	319	elem.flags = 0;
	320
	321	iter->err = iter->fn(ctx, set, iter, &elem);
	322	if (iter->err < 0)
	323	return;
	324	cont:
	325	iter->count++;
96518518 PM	326	}
96518518 PM	327	}
96518518 PM	328	}
96518518 PM	329
20a69341 PM	330	static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
	331	{
	332	return sizeof(struct nft_hash);
	333	}
96518518	334
20a69341	335	static int nft_hash_init(const struct nft_set *set,
c50b960c	336	const struct nft_set_desc *desc,
96518518 PM	337	const struct nlattr * const tb[])
96518518 PM	338	{
20a69341	339	struct nft_hash *priv = nft_set_priv(set);
ce6eb0d7	340	struct nft_hash_table *tbl;
c50b960c	341	unsigned int size;
96518518 PM	342
	343	if (unlikely(!nft_hash_rnd_initted)) {
	344	get_random_bytes(&nft_hash_rnd, 4);
	345	nft_hash_rnd_initted = true;
	346	}
	347
c50b960c PM	348	size = NFT_HASH_MIN_SIZE;
	349	if (desc->size)
	350	size = nft_hash_tbl_size(desc->size);
	351
	352	tbl = nft_hash_tbl_alloc(size);
ce6eb0d7	353	if (tbl == NULL)
96518518	354	return -ENOMEM;
ce6eb0d7	355	RCU_INIT_POINTER(priv->tbl, tbl);
96518518	356	return 0;
96518518 PM	357	}
96518518 PM	358
20a69341	359	static void nft_hash_destroy(const struct nft_set *set)
96518518	360	{
20a69341	361	const struct nft_hash *priv = nft_set_priv(set);
ce6eb0d7 PM	362	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
ce6eb0d7 PM	363	struct nft_hash_elem he, next;
96518518 PM	364	unsigned int i;
96518518 PM	365
ce6eb0d7 PM	366	for (i = 0; i < tbl->size; i++) {
	367	for (he = nft_dereference(tbl->buckets[i]); he != NULL;
	368	he = next) {
	369	next = nft_dereference(he->next);
	370	nft_hash_elem_destroy(set, he);
96518518 PM	371	}
96518518 PM	372	}
ce6eb0d7	373	kfree(tbl);
96518518 PM	374	}
96518518 PM	375
c50b960c PM	376	static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
	377	struct nft_set_estimate *est)
	378	{
	379	unsigned int esize;
	380
	381	esize = sizeof(struct nft_hash_elem);
	382	if (features & NFT_SET_MAP)
	383	esize += FIELD_SIZEOF(struct nft_hash_elem, data[0]);
	384
	385	if (desc->size) {
	386	est->size = sizeof(struct nft_hash) +
	387	nft_hash_tbl_size(desc->size) *
	388	sizeof(struct nft_hash_elem *) +
	389	desc->size * esize;
	390	} else {
	391	/* Resizing happens when the load drops below 30% or goes
	392	* above 75%. The average of 52.5% load (approximated by 50%)
	393	* is used for the size estimation of the hash buckets,
	394	* meaning we calculate two buckets per element.
	395	*/
	396	est->size = esize + 2 * sizeof(struct nft_hash_elem *);
	397	}
	398
	399	est->class = NFT_SET_CLASS_O_1;
	400
	401	return true;
	402	}
	403
20a69341 PM	404	static struct nft_set_ops nft_hash_ops __read_mostly = {
20a69341 PM	405	.privsize = nft_hash_privsize,
c50b960c	406	.estimate = nft_hash_estimate,
96518518 PM	407	.init = nft_hash_init,
96518518 PM	408	.destroy = nft_hash_destroy,
20a69341 PM	409	.get = nft_hash_get,
	410	.insert = nft_hash_insert,
	411	.remove = nft_hash_remove,
	412	.lookup = nft_hash_lookup,
	413	.walk = nft_hash_walk,
	414	.features = NFT_SET_MAP,
	415	.owner = THIS_MODULE,
96518518 PM	416	};
	417
	418	static int __init nft_hash_module_init(void)
	419	{
20a69341	420	return nft_register_set(&nft_hash_ops);
96518518 PM	421	}
	422
	423	static void __exit nft_hash_module_exit(void)
	424	{
20a69341	425	nft_unregister_set(&nft_hash_ops);
96518518 PM	426	}
	427
	428	module_init(nft_hash_module_init);
	429	module_exit(nft_hash_module_exit);
	430
	431	MODULE_LICENSE("GPL");
	432	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
20a69341	433	MODULE_ALIAS_NFT_SET();