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

 /*
  * Copyright (c) 2008 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/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables.h>

 struct nft_hash {
 	struct hlist_head	*hash;
 	unsigned int		hsize;
 	enum nft_registers	sreg:8;
 	enum nft_registers	dreg:8;
 	u8			klen;
 	u8			dlen;
 	u16			flags;
 };

 struct nft_hash_elem {
 	struct hlist_node	hnode;
 	struct nft_data		key;
 	struct nft_data		data[];
 };

 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;

 	// FIXME: can we reasonably guarantee the upper bits are fixed?
 	h = jhash2(data->data, len >> 2, nft_hash_rnd);
 	return ((u64)h * hsize) >> 32;
 }

 static void nft_hash_eval(const struct nft_expr *expr,
 			  struct nft_data data[NFT_REG_MAX + 1],
 			  const struct nft_pktinfo *pkt)
 {
 	const struct nft_hash *priv = nft_expr_priv(expr);
 	const struct nft_hash_elem *elem;
 	const struct nft_data *key = &data[priv->sreg];
 	unsigned int h;

 	h = nft_hash_data(key, priv->hsize, priv->klen);
 	hlist_for_each_entry(elem, &priv->hash[h], hnode) {
 		if (nft_data_cmp(&elem->key, key, priv->klen))
 			continue;
 		if (priv->flags & NFT_HASH_MAP)
 			nft_data_copy(&data[priv->dreg], elem->data);
 		return;
 	}
 	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
 }

 static void nft_hash_elem_destroy(const struct nft_expr *expr,
 				  struct nft_hash_elem *elem)
 {
 	const struct nft_hash *priv = nft_expr_priv(expr);

 	nft_data_uninit(&elem->key, NFT_DATA_VALUE);
 	if (priv->flags & NFT_HASH_MAP)
 		nft_data_uninit(elem->data, nft_dreg_to_type(priv->dreg));
 	kfree(elem);
 }

 static const struct nla_policy nft_he_policy[NFTA_HE_MAX + 1] = {
 	[NFTA_HE_KEY]		= { .type = NLA_NESTED },
 	[NFTA_HE_DATA]		= { .type = NLA_NESTED },
 };

 static int nft_hash_elem_init(const struct nft_ctx *ctx,
 			      const struct nft_expr *expr,
 			      const struct nlattr *nla,
 			      struct nft_hash_elem **new)
 {
 	struct nft_hash *priv = nft_expr_priv(expr);
 	struct nlattr *tb[NFTA_HE_MAX + 1];
 	struct nft_hash_elem *elem;
 	struct nft_data_desc d1, d2;
 	unsigned int size;
 	int err;

 	err = nla_parse_nested(tb, NFTA_HE_MAX, nla, nft_he_policy);
 	if (err < 0)
 		return err;

 	if (tb[NFTA_HE_KEY] == NULL)
 		return -EINVAL;
 	size = sizeof(*elem);

 	if (priv->flags & NFT_HASH_MAP) {
 		if (tb[NFTA_HE_DATA] == NULL)
 			return -EINVAL;
 		size += sizeof(elem->data[0]);
 	} else {
 		if (tb[NFTA_HE_DATA] != NULL)
 			return -EINVAL;
 	}

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

 	err = nft_data_init(ctx, &elem->key, &d1, tb[NFTA_HE_KEY]);
 	if (err < 0)
 		goto err1;
 	err = -EINVAL;
 	if (d1.type != NFT_DATA_VALUE || d1.len != priv->klen)
 		goto err2;

 	if (tb[NFTA_HE_DATA] != NULL) {
 		err = nft_data_init(ctx, elem->data, &d2, tb[NFTA_HE_DATA]);
 		if (err < 0)
 			goto err2;
 		err = nft_validate_data_load(ctx, priv->dreg, elem->data, d2.type);
 		if (err < 0)
 			goto err3;
 	}

 	*new = elem;
 	return 0;

 err3:
 	nft_data_uninit(elem->data, d2.type);
 err2:
 	nft_data_uninit(&elem->key, d1.type);
 err1:
 	kfree(elem);
 	return err;
 }

 static int nft_hash_elem_dump(struct sk_buff *skb, const struct nft_expr *expr,
 			      const struct nft_hash_elem *elem)

 {
 	const struct nft_hash *priv = nft_expr_priv(expr);
 	struct nlattr *nest;

 	nest = nla_nest_start(skb, NFTA_LIST_ELEM);
 	if (nest == NULL)
 		goto nla_put_failure;

 	if (nft_data_dump(skb, NFTA_HE_KEY, &elem->key,
 			  NFT_DATA_VALUE, priv->klen) < 0)
 		goto nla_put_failure;

 	if (priv->flags & NFT_HASH_MAP) {
 		if (nft_data_dump(skb, NFTA_HE_DATA, elem->data,
 				  NFT_DATA_VALUE, priv->dlen) < 0)
 			goto nla_put_failure;
 	}

 	nla_nest_end(skb, nest);
 	return 0;

 nla_put_failure:
 	return -1;
 }

 static void nft_hash_destroy(const struct nft_ctx *ctx,
 			     const struct nft_expr *expr)
 {
 	const struct nft_hash *priv = nft_expr_priv(expr);
 	const struct hlist_node *next;
 	struct nft_hash_elem *elem;
 	unsigned int i;

 	for (i = 0; i < priv->hsize; i++) {
 		hlist_for_each_entry_safe(elem, next, &priv->hash[i], hnode) {
 			hlist_del(&elem->hnode);
 			nft_hash_elem_destroy(expr, elem);
 		}
 	}
 	kfree(priv->hash);
 }

 static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
 	[NFTA_HASH_FLAGS]	= { .type = NLA_U32 },
 	[NFTA_HASH_SREG]	= { .type = NLA_U32 },
 	[NFTA_HASH_DREG]	= { .type = NLA_U32 },
 	[NFTA_HASH_KLEN]	= { .type = NLA_U32 },
 	[NFTA_HASH_ELEMENTS]	= { .type = NLA_NESTED },
 };

 static int nft_hash_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 			 const struct nlattr * const tb[])
 {
 	struct nft_hash *priv = nft_expr_priv(expr);
 	struct nft_hash_elem *elem, *uninitialized_var(new);
 	const struct nlattr *nla;
 	unsigned int cnt, i;
 	unsigned int h;
 	int err, rem;

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

 	if (tb[NFTA_HASH_SREG] == NULL ||
 	    tb[NFTA_HASH_KLEN] == NULL ||
 	    tb[NFTA_HASH_ELEMENTS] == NULL)
 		return -EINVAL;

 	if (tb[NFTA_HASH_FLAGS] != NULL) {
 		priv->flags = ntohl(nla_get_be32(tb[NFTA_HASH_FLAGS]));
 		if (priv->flags & ~NFT_HASH_MAP)
 			return -EINVAL;
 	}

 	priv->sreg = ntohl(nla_get_be32(tb[NFTA_HASH_SREG]));
 	err = nft_validate_input_register(priv->sreg);
 	if (err < 0)
 		return err;

 	if (tb[NFTA_HASH_DREG] != NULL) {
 		if (!(priv->flags & NFT_HASH_MAP))
 			return -EINVAL;
 		priv->dreg = ntohl(nla_get_be32(tb[NFTA_HASH_DREG]));
 		err = nft_validate_output_register(priv->dreg);
 		if (err < 0)
 			return err;
 	}

 	priv->klen = ntohl(nla_get_be32(tb[NFTA_HASH_KLEN]));
 	if (priv->klen == 0)
 		return -EINVAL;

 	cnt = 0;
 	nla_for_each_nested(nla, tb[NFTA_HASH_ELEMENTS], rem) {
 		if (nla_type(nla) != NFTA_LIST_ELEM)
 			return -EINVAL;
 		cnt++;
 	}

 	/* Aim for a load factor of 0.75 */
 	cnt = cnt * 4 / 3;

 	priv->hash = kcalloc(cnt, sizeof(struct hlist_head), GFP_KERNEL);
 	if (priv->hash == NULL)
 		return -ENOMEM;
 	priv->hsize = cnt;

 	for (i = 0; i < cnt; i++)
 		INIT_HLIST_HEAD(&priv->hash[i]);

 	err = -ENOMEM;
 	nla_for_each_nested(nla, tb[NFTA_HASH_ELEMENTS], rem) {
 		err = nft_hash_elem_init(ctx, expr, nla, &new);
 		if (err < 0)
 			goto err1;

 		h = nft_hash_data(&new->key, priv->hsize, priv->klen);
 		hlist_for_each_entry(elem, &priv->hash[h], hnode) {
 			if (nft_data_cmp(&elem->key, &new->key, priv->klen))
 				continue;
 			nft_hash_elem_destroy(expr, new);
 			err = -EEXIST;
 			goto err1;
 		}
 		hlist_add_head(&new->hnode, &priv->hash[h]);
 	}
 	return 0;

 err1:
 	nft_hash_destroy(ctx, expr);
 	return err;
 }

 static int nft_hash_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
 	const struct nft_hash *priv = nft_expr_priv(expr);
 	const struct nft_hash_elem *elem;
 	struct nlattr *list;
 	unsigned int i;

 	if (priv->flags)
 		if (nla_put_be32(skb, NFTA_HASH_FLAGS, htonl(priv->flags)))
 			goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_HASH_SREG, htonl(priv->sreg)))
 		goto nla_put_failure;
 	if (priv->flags & NFT_HASH_MAP)
 		if (nla_put_be32(skb, NFTA_HASH_DREG, htonl(priv->dreg)))
 			goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_HASH_KLEN, htonl(priv->klen)))
 		goto nla_put_failure;

 	list = nla_nest_start(skb, NFTA_HASH_ELEMENTS);
 	if (list == NULL)
 		goto nla_put_failure;

 	for (i = 0; i < priv->hsize; i++) {
 		hlist_for_each_entry(elem, &priv->hash[i], hnode) {
 			if (nft_hash_elem_dump(skb, expr, elem) < 0)
 				goto nla_put_failure;
 		}
 	}

 	nla_nest_end(skb, list);
 	return 0;

 nla_put_failure:
 	return -1;
 }

 static struct nft_expr_ops nft_hash_ops __read_mostly = {
 	.name		= "hash",
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_hash)),
 	.owner		= THIS_MODULE,
 	.eval		= nft_hash_eval,
 	.init		= nft_hash_init,
 	.destroy	= nft_hash_destroy,
 	.dump		= nft_hash_dump,
 	.policy		= nft_hash_policy,
 	.maxattr	= NFTA_HASH_MAX,
 };

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

 static void __exit nft_hash_module_exit(void)
 {
 	nft_unregister_expr(&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_EXPR("hash");
	/*
	* Copyright (c) 2008 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/netfilter.h>
	#include <linux/netfilter/nf_tables.h>
	#include <net/netfilter/nf_tables.h>

	struct nft_hash {
	struct hlist_head *hash;
	unsigned int hsize;
	enum nft_registers sreg:8;
	enum nft_registers dreg:8;
	u8 klen;
	u8 dlen;
	u16 flags;
	};

	struct nft_hash_elem {
	struct hlist_node hnode;
	struct nft_data key;
	struct nft_data data[];
	};

	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;

	// FIXME: can we reasonably guarantee the upper bits are fixed?
	h = jhash2(data->data, len >> 2, nft_hash_rnd);
	return ((u64)h * hsize) >> 32;
	}

	static void nft_hash_eval(const struct nft_expr *expr,
	struct nft_data data[NFT_REG_MAX + 1],
	const struct nft_pktinfo *pkt)
	{
	const struct nft_hash *priv = nft_expr_priv(expr);
	const struct nft_hash_elem *elem;
	const struct nft_data *key = &data[priv->sreg];
	unsigned int h;

	h = nft_hash_data(key, priv->hsize, priv->klen);
	hlist_for_each_entry(elem, &priv->hash[h], hnode) {
	if (nft_data_cmp(&elem->key, key, priv->klen))
	continue;
	if (priv->flags & NFT_HASH_MAP)
	nft_data_copy(&data[priv->dreg], elem->data);
	return;
	}
	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
	}

	static void nft_hash_elem_destroy(const struct nft_expr *expr,
	struct nft_hash_elem *elem)
	{
	const struct nft_hash *priv = nft_expr_priv(expr);

	nft_data_uninit(&elem->key, NFT_DATA_VALUE);
	if (priv->flags & NFT_HASH_MAP)
	nft_data_uninit(elem->data, nft_dreg_to_type(priv->dreg));
	kfree(elem);
	}

	static const struct nla_policy nft_he_policy[NFTA_HE_MAX + 1] = {
	[NFTA_HE_KEY] = { .type = NLA_NESTED },
	[NFTA_HE_DATA] = { .type = NLA_NESTED },
	};

	static int nft_hash_elem_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr *nla,
	struct nft_hash_elem **new)
	{
	struct nft_hash *priv = nft_expr_priv(expr);
	struct nlattr *tb[NFTA_HE_MAX + 1];
	struct nft_hash_elem *elem;
	struct nft_data_desc d1, d2;
	unsigned int size;
	int err;

	err = nla_parse_nested(tb, NFTA_HE_MAX, nla, nft_he_policy);
	if (err < 0)
	return err;

	if (tb[NFTA_HE_KEY] == NULL)
	return -EINVAL;
	size = sizeof(*elem);

	if (priv->flags & NFT_HASH_MAP) {
	if (tb[NFTA_HE_DATA] == NULL)
	return -EINVAL;
	size += sizeof(elem->data[0]);
	} else {
	if (tb[NFTA_HE_DATA] != NULL)
	return -EINVAL;
	}

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

	err = nft_data_init(ctx, &elem->key, &d1, tb[NFTA_HE_KEY]);
	if (err < 0)
	goto err1;
	err = -EINVAL;
	if (d1.type != NFT_DATA_VALUE \|\| d1.len != priv->klen)
	goto err2;

	if (tb[NFTA_HE_DATA] != NULL) {
	err = nft_data_init(ctx, elem->data, &d2, tb[NFTA_HE_DATA]);
	if (err < 0)
	goto err2;
	err = nft_validate_data_load(ctx, priv->dreg, elem->data, d2.type);
	if (err < 0)
	goto err3;
	}

	*new = elem;
	return 0;

	err3:
	nft_data_uninit(elem->data, d2.type);
	err2:
	nft_data_uninit(&elem->key, d1.type);
	err1:
	kfree(elem);
	return err;
	}

	static int nft_hash_elem_dump(struct sk_buff skb, const struct nft_expr expr,
	const struct nft_hash_elem *elem)

	{
	const struct nft_hash *priv = nft_expr_priv(expr);
	struct nlattr *nest;

	nest = nla_nest_start(skb, NFTA_LIST_ELEM);
	if (nest == NULL)
	goto nla_put_failure;

	if (nft_data_dump(skb, NFTA_HE_KEY, &elem->key,
	NFT_DATA_VALUE, priv->klen) < 0)
	goto nla_put_failure;

	if (priv->flags & NFT_HASH_MAP) {
	if (nft_data_dump(skb, NFTA_HE_DATA, elem->data,
	NFT_DATA_VALUE, priv->dlen) < 0)
	goto nla_put_failure;
	}

	nla_nest_end(skb, nest);
	return 0;

	nla_put_failure:
	return -1;
	}

	static void nft_hash_destroy(const struct nft_ctx *ctx,
	const struct nft_expr *expr)
	{
	const struct nft_hash *priv = nft_expr_priv(expr);
	const struct hlist_node *next;
	struct nft_hash_elem *elem;
	unsigned int i;

	for (i = 0; i < priv->hsize; i++) {
	hlist_for_each_entry_safe(elem, next, &priv->hash[i], hnode) {
	hlist_del(&elem->hnode);
	nft_hash_elem_destroy(expr, elem);
	}
	}
	kfree(priv->hash);
	}

	static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
	[NFTA_HASH_FLAGS] = { .type = NLA_U32 },
	[NFTA_HASH_SREG] = { .type = NLA_U32 },
	[NFTA_HASH_DREG] = { .type = NLA_U32 },
	[NFTA_HASH_KLEN] = { .type = NLA_U32 },
	[NFTA_HASH_ELEMENTS] = { .type = NLA_NESTED },
	};

	static int nft_hash_init(const struct nft_ctx ctx, const struct nft_expr expr,
	const struct nlattr * const tb[])
	{
	struct nft_hash *priv = nft_expr_priv(expr);
	struct nft_hash_elem elem, uninitialized_var(new);
	const struct nlattr *nla;
	unsigned int cnt, i;
	unsigned int h;
	int err, rem;

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

	if (tb[NFTA_HASH_SREG] == NULL \|\|
	tb[NFTA_HASH_KLEN] == NULL \|\|
	tb[NFTA_HASH_ELEMENTS] == NULL)
	return -EINVAL;

	if (tb[NFTA_HASH_FLAGS] != NULL) {
	priv->flags = ntohl(nla_get_be32(tb[NFTA_HASH_FLAGS]));
	if (priv->flags & ~NFT_HASH_MAP)
	return -EINVAL;
	}

	priv->sreg = ntohl(nla_get_be32(tb[NFTA_HASH_SREG]));
	err = nft_validate_input_register(priv->sreg);
	if (err < 0)
	return err;

	if (tb[NFTA_HASH_DREG] != NULL) {
	if (!(priv->flags & NFT_HASH_MAP))
	return -EINVAL;
	priv->dreg = ntohl(nla_get_be32(tb[NFTA_HASH_DREG]));
	err = nft_validate_output_register(priv->dreg);
	if (err < 0)
	return err;
	}

	priv->klen = ntohl(nla_get_be32(tb[NFTA_HASH_KLEN]));
	if (priv->klen == 0)
	return -EINVAL;

	cnt = 0;
	nla_for_each_nested(nla, tb[NFTA_HASH_ELEMENTS], rem) {
	if (nla_type(nla) != NFTA_LIST_ELEM)
	return -EINVAL;
	cnt++;
	}

	/* Aim for a load factor of 0.75 */
	cnt = cnt * 4 / 3;

	priv->hash = kcalloc(cnt, sizeof(struct hlist_head), GFP_KERNEL);
	if (priv->hash == NULL)
	return -ENOMEM;
	priv->hsize = cnt;

	for (i = 0; i < cnt; i++)
	INIT_HLIST_HEAD(&priv->hash[i]);

	err = -ENOMEM;
	nla_for_each_nested(nla, tb[NFTA_HASH_ELEMENTS], rem) {
	err = nft_hash_elem_init(ctx, expr, nla, &new);
	if (err < 0)
	goto err1;

	h = nft_hash_data(&new->key, priv->hsize, priv->klen);
	hlist_for_each_entry(elem, &priv->hash[h], hnode) {
	if (nft_data_cmp(&elem->key, &new->key, priv->klen))
	continue;
	nft_hash_elem_destroy(expr, new);
	err = -EEXIST;
	goto err1;
	}
	hlist_add_head(&new->hnode, &priv->hash[h]);
	}
	return 0;

	err1:
	nft_hash_destroy(ctx, expr);
	return err;
	}

	static int nft_hash_dump(struct sk_buff skb, const struct nft_expr expr)
	{
	const struct nft_hash *priv = nft_expr_priv(expr);
	const struct nft_hash_elem *elem;
	struct nlattr *list;
	unsigned int i;

	if (priv->flags)
	if (nla_put_be32(skb, NFTA_HASH_FLAGS, htonl(priv->flags)))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HASH_SREG, htonl(priv->sreg)))
	goto nla_put_failure;
	if (priv->flags & NFT_HASH_MAP)
	if (nla_put_be32(skb, NFTA_HASH_DREG, htonl(priv->dreg)))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HASH_KLEN, htonl(priv->klen)))
	goto nla_put_failure;

	list = nla_nest_start(skb, NFTA_HASH_ELEMENTS);
	if (list == NULL)
	goto nla_put_failure;

	for (i = 0; i < priv->hsize; i++) {
	hlist_for_each_entry(elem, &priv->hash[i], hnode) {
	if (nft_hash_elem_dump(skb, expr, elem) < 0)
	goto nla_put_failure;
	}
	}

	nla_nest_end(skb, list);
	return 0;

	nla_put_failure:
	return -1;
	}

	static struct nft_expr_ops nft_hash_ops __read_mostly = {
	.name = "hash",
	.size = NFT_EXPR_SIZE(sizeof(struct nft_hash)),
	.owner = THIS_MODULE,
	.eval = nft_hash_eval,
	.init = nft_hash_init,
	.destroy = nft_hash_destroy,
	.dump = nft_hash_dump,
	.policy = nft_hash_policy,
	.maxattr = NFTA_HASH_MAX,
	};

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

	static void __exit nft_hash_module_exit(void)
	{
	nft_unregister_expr(&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_EXPR("hash");