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/log2.h>
 #include <linux/jhash.h>
 #include <linux/netlink.h>
 #include <linux/rhashtable.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables.h>

 /* We target a hash table size of 4, element hint is 75% of final size */
 #define NFT_HASH_ELEMENT_HINT 3

 struct nft_hash_elem {
 	struct rhash_head		node;
 	struct nft_data			key;
 	struct nft_data			data[];
 };

 static bool nft_hash_lookup(const struct nft_set *set,
 			    const struct nft_data *key,
 			    struct nft_data *data)
 {
 	struct rhashtable *priv = nft_set_priv(set);
 	const struct nft_hash_elem *he;

 	he = rhashtable_lookup(priv, key);
 	if (he && set->flags & NFT_SET_MAP)
 		nft_data_copy(data, he->data);

 	return !!he;
 }

 static int nft_hash_insert(const struct nft_set *set,
 			   const struct nft_set_elem *elem)
 {
 	struct rhashtable *priv = nft_set_priv(set);
 	struct nft_hash_elem *he;
 	unsigned int size;

 	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);

 	rhashtable_insert(priv, &he->node);

 	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 rhashtable *priv = nft_set_priv(set);

 	rhashtable_remove(priv, elem->cookie);
 	synchronize_rcu();
 	kfree(elem->cookie);
 }

 struct nft_compare_arg {
 	const struct nft_set *set;
 	struct nft_set_elem *elem;
 };

 static bool nft_hash_compare(void *ptr, void *arg)
 {
 	struct nft_hash_elem *he = ptr;
 	struct nft_compare_arg *x = arg;

 	if (!nft_data_cmp(&he->key, &x->elem->key, x->set->klen)) {
 		x->elem->cookie = he;
 		x->elem->flags = 0;
 		if (x->set->flags & NFT_SET_MAP)
 			nft_data_copy(&x->elem->data, he->data);

 		return true;
 	}

 	return false;
 }

 static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem)
 {
 	struct rhashtable *priv = nft_set_priv(set);
 	struct nft_compare_arg arg = {
 		.set = set,
 		.elem = elem,
 	};

 	if (rhashtable_lookup_compare(priv, &elem->key,
 				      &nft_hash_compare, &arg))
 		return 0;

 	return -ENOENT;
 }

 static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
 			  struct nft_set_iter *iter)
 {
 	struct rhashtable *priv = nft_set_priv(set);
 	const struct nft_hash_elem *he;
 	struct rhashtable_iter hti;
 	struct nft_set_elem elem;
 	int err;

 	err = rhashtable_walk_init(priv, &hti);
 	iter->err = err;
 	if (err)
 		return;

 	err = rhashtable_walk_start(&hti);
 	if (err && err != -EAGAIN) {
 		iter->err = err;
 		goto out;
 	}

 	while ((he = rhashtable_walk_next(&hti))) {
 		if (IS_ERR(he)) {
 			err = PTR_ERR(he);
 			if (err != -EAGAIN) {
 				iter->err = err;
 				goto out;
 			}
 		}

 		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)
 			goto out;

 cont:
 		iter->count++;
 	}

 out:
 	rhashtable_walk_stop(&hti);
 	rhashtable_walk_exit(&hti);
 }

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

 static int nft_hash_init(const struct nft_set *set,
 			 const struct nft_set_desc *desc,
 			 const struct nlattr * const tb[])
 {
 	struct rhashtable *priv = nft_set_priv(set);
 	struct rhashtable_params params = {
 		.nelem_hint = desc->size ? : NFT_HASH_ELEMENT_HINT,
 		.head_offset = offsetof(struct nft_hash_elem, node),
 		.key_offset = offsetof(struct nft_hash_elem, key),
 		.key_len = set->klen,
 		.hashfn = jhash,
 	};

 	return rhashtable_init(priv, &params);
 }

 static void nft_hash_destroy(const struct nft_set *set)
 {
 	struct rhashtable *priv = nft_set_priv(set);
 	const struct bucket_table *tbl;
 	struct nft_hash_elem *he;
 	struct rhash_head *pos, *next;
 	unsigned int i;

 	/* Stop an eventual async resizing */
 	priv->being_destroyed = true;
 	mutex_lock(&priv->mutex);

 	tbl = rht_dereference(priv->tbl, priv);
 	for (i = 0; i < tbl->size; i++) {
 		rht_for_each_entry_safe(he, pos, next, tbl, i, node)
 			nft_hash_elem_destroy(set, he);
 	}
 	mutex_unlock(&priv->mutex);

 	rhashtable_destroy(priv);
 }

 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 rhashtable) +
 			    roundup_pow_of_two(desc->size * 4 / 3) *
 			    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();
	/*
	* 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/rhashtable.h>
	#include <linux/netfilter.h>
	#include <linux/netfilter/nf_tables.h>
	#include <net/netfilter/nf_tables.h>

	/* We target a hash table size of 4, element hint is 75% of final size */
	#define NFT_HASH_ELEMENT_HINT 3

	struct nft_hash_elem {
	struct rhash_head node;
	struct nft_data key;
	struct nft_data data[];
	};

	static bool nft_hash_lookup(const struct nft_set *set,
	const struct nft_data *key,
	struct nft_data *data)
	{
	struct rhashtable *priv = nft_set_priv(set);
	const struct nft_hash_elem *he;

	he = rhashtable_lookup(priv, key);
	if (he && set->flags & NFT_SET_MAP)
	nft_data_copy(data, he->data);

	return !!he;
	}

	static int nft_hash_insert(const struct nft_set *set,
	const struct nft_set_elem *elem)
	{
	struct rhashtable *priv = nft_set_priv(set);
	struct nft_hash_elem *he;
	unsigned int size;

	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);

	rhashtable_insert(priv, &he->node);

	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 rhashtable *priv = nft_set_priv(set);

	rhashtable_remove(priv, elem->cookie);
	synchronize_rcu();
	kfree(elem->cookie);
	}

	struct nft_compare_arg {
	const struct nft_set *set;
	struct nft_set_elem *elem;
	};

	static bool nft_hash_compare(void ptr, void arg)
	{
	struct nft_hash_elem *he = ptr;
	struct nft_compare_arg *x = arg;

	if (!nft_data_cmp(&he->key, &x->elem->key, x->set->klen)) {
	x->elem->cookie = he;
	x->elem->flags = 0;
	if (x->set->flags & NFT_SET_MAP)
	nft_data_copy(&x->elem->data, he->data);

	return true;
	}

	return false;
	}

	static int nft_hash_get(const struct nft_set set, struct nft_set_elem elem)
	{
	struct rhashtable *priv = nft_set_priv(set);
	struct nft_compare_arg arg = {
	.set = set,
	.elem = elem,
	};

	if (rhashtable_lookup_compare(priv, &elem->key,
	&nft_hash_compare, &arg))
	return 0;

	return -ENOENT;
	}

	static void nft_hash_walk(const struct nft_ctx ctx, const struct nft_set set,
	struct nft_set_iter *iter)
	{
	struct rhashtable *priv = nft_set_priv(set);
	const struct nft_hash_elem *he;
	struct rhashtable_iter hti;
	struct nft_set_elem elem;
	int err;

	err = rhashtable_walk_init(priv, &hti);
	iter->err = err;
	if (err)
	return;

	err = rhashtable_walk_start(&hti);
	if (err && err != -EAGAIN) {
	iter->err = err;
	goto out;
	}

	while ((he = rhashtable_walk_next(&hti))) {
	if (IS_ERR(he)) {
	err = PTR_ERR(he);
	if (err != -EAGAIN) {
	iter->err = err;
	goto out;
	}
	}

	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)
	goto out;

	cont:
	iter->count++;
	}

	out:
	rhashtable_walk_stop(&hti);
	rhashtable_walk_exit(&hti);
	}

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

	static int nft_hash_init(const struct nft_set *set,
	const struct nft_set_desc *desc,
	const struct nlattr * const tb[])
	{
	struct rhashtable *priv = nft_set_priv(set);
	struct rhashtable_params params = {
	.nelem_hint = desc->size ? : NFT_HASH_ELEMENT_HINT,
	.head_offset = offsetof(struct nft_hash_elem, node),
	.key_offset = offsetof(struct nft_hash_elem, key),
	.key_len = set->klen,
	.hashfn = jhash,
	};

	return rhashtable_init(priv, &params);
	}

	static void nft_hash_destroy(const struct nft_set *set)
	{
	struct rhashtable *priv = nft_set_priv(set);
	const struct bucket_table *tbl;
	struct nft_hash_elem *he;
	struct rhash_head pos, next;
	unsigned int i;

	/* Stop an eventual async resizing */
	priv->being_destroyed = true;
	mutex_lock(&priv->mutex);

	tbl = rht_dereference(priv->tbl, priv);
	for (i = 0; i < tbl->size; i++) {
	rht_for_each_entry_safe(he, pos, next, tbl, i, node)
	nft_hash_elem_destroy(set, he);
	}
	mutex_unlock(&priv->mutex);

	rhashtable_destroy(priv);
	}

	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 rhashtable) +
	roundup_pow_of_two(desc->size * 4 / 3) *
	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();