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

 /*
  * Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
  *
  * 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.
  *
  */

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

 struct nft_jhash {
 	enum nft_registers      sreg:8;
 	enum nft_registers      dreg:8;
 	u8			len;
 	bool			autogen_seed:1;
 	u32			modulus;
 	u32			seed;
 	u32			offset;
 	struct nft_set		*map;
 };

 static void nft_jhash_eval(const struct nft_expr *expr,
 			   struct nft_regs *regs,
 			   const struct nft_pktinfo *pkt)
 {
 	struct nft_jhash *priv = nft_expr_priv(expr);
 	const void *data = &regs->data[priv->sreg];
 	u32 h;

 	h = reciprocal_scale(jhash(data, priv->len, priv->seed),
 			     priv->modulus);

 	regs->data[priv->dreg] = h + priv->offset;
 }

 static void nft_jhash_map_eval(const struct nft_expr *expr,
 			       struct nft_regs *regs,
 			       const struct nft_pktinfo *pkt)
 {
 	struct nft_jhash *priv = nft_expr_priv(expr);
 	const void *data = &regs->data[priv->sreg];
 	const struct nft_set *map = priv->map;
 	const struct nft_set_ext *ext;
 	u32 result;
 	bool found;

 	result = reciprocal_scale(jhash(data, priv->len, priv->seed),
 					priv->modulus) + priv->offset;

 	found = map->ops->lookup(nft_net(pkt), map, &result, &ext);
 	if (!found)
 		return;

 	nft_data_copy(&regs->data[priv->dreg],
 		      nft_set_ext_data(ext), map->dlen);
 }

 struct nft_symhash {
 	enum nft_registers      dreg:8;
 	u32			modulus;
 	u32			offset;
 	struct nft_set		*map;
 };

 static void nft_symhash_eval(const struct nft_expr *expr,
 			     struct nft_regs *regs,
 			     const struct nft_pktinfo *pkt)
 {
 	struct nft_symhash *priv = nft_expr_priv(expr);
 	struct sk_buff *skb = pkt->skb;
 	u32 h;

 	h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus);

 	regs->data[priv->dreg] = h + priv->offset;
 }

 static void nft_symhash_map_eval(const struct nft_expr *expr,
 				 struct nft_regs *regs,
 				 const struct nft_pktinfo *pkt)
 {
 	struct nft_symhash *priv = nft_expr_priv(expr);
 	struct sk_buff *skb = pkt->skb;
 	const struct nft_set *map = priv->map;
 	const struct nft_set_ext *ext;
 	u32 result;
 	bool found;

 	result = reciprocal_scale(__skb_get_hash_symmetric(skb),
 				  priv->modulus) + priv->offset;

 	found = map->ops->lookup(nft_net(pkt), map, &result, &ext);
 	if (!found)
 		return;

 	nft_data_copy(&regs->data[priv->dreg],
 		      nft_set_ext_data(ext), map->dlen);
 }

 static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
 	[NFTA_HASH_SREG]	= { .type = NLA_U32 },
 	[NFTA_HASH_DREG]	= { .type = NLA_U32 },
 	[NFTA_HASH_LEN]		= { .type = NLA_U32 },
 	[NFTA_HASH_MODULUS]	= { .type = NLA_U32 },
 	[NFTA_HASH_SEED]	= { .type = NLA_U32 },
 	[NFTA_HASH_OFFSET]	= { .type = NLA_U32 },
 	[NFTA_HASH_TYPE]	= { .type = NLA_U32 },
 	[NFTA_HASH_SET_NAME]	= { .type = NLA_STRING,
 				    .len = NFT_SET_MAXNAMELEN - 1 },
 	[NFTA_HASH_SET_ID]	= { .type = NLA_U32 },
 };

 static int nft_jhash_init(const struct nft_ctx *ctx,
 			  const struct nft_expr *expr,
 			  const struct nlattr * const tb[])
 {
 	struct nft_jhash *priv = nft_expr_priv(expr);
 	u32 len;
 	int err;

 	if (!tb[NFTA_HASH_SREG] ||
 	    !tb[NFTA_HASH_DREG] ||
 	    !tb[NFTA_HASH_LEN]  ||
 	    !tb[NFTA_HASH_MODULUS])
 		return -EINVAL;

 	if (tb[NFTA_HASH_OFFSET])
 		priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));

 	priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]);
 	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);

 	err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
 	if (err < 0)
 		return err;
 	if (len == 0)
 		return -ERANGE;

 	priv->len = len;

 	priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
 	if (priv->modulus < 1)
 		return -ERANGE;

 	if (priv->offset + priv->modulus - 1 < priv->offset)
 		return -EOVERFLOW;

 	if (tb[NFTA_HASH_SEED]) {
 		priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
 	} else {
 		priv->autogen_seed = true;
 		get_random_bytes(&priv->seed, sizeof(priv->seed));
 	}

 	return nft_validate_register_load(priv->sreg, len) &&
 	       nft_validate_register_store(ctx, priv->dreg, NULL,
 					   NFT_DATA_VALUE, sizeof(u32));
 }

 static int nft_jhash_map_init(const struct nft_ctx *ctx,
 			      const struct nft_expr *expr,
 			      const struct nlattr * const tb[])
 {
 	struct nft_jhash *priv = nft_expr_priv(expr);
 	u8 genmask = nft_genmask_next(ctx->net);

 	nft_jhash_init(ctx, expr, tb);
 	priv->map = nft_set_lookup_global(ctx->net, ctx->table,
 					  tb[NFTA_HASH_SET_NAME],
 					  tb[NFTA_HASH_SET_ID], genmask);
 	return PTR_ERR_OR_ZERO(priv->map);
 }

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

 	if (!tb[NFTA_HASH_DREG]    ||
 	    !tb[NFTA_HASH_MODULUS])
 		return -EINVAL;

 	if (tb[NFTA_HASH_OFFSET])
 		priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));

 	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);

 	priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
 	if (priv->modulus <= 1)
 		return -ERANGE;

 	if (priv->offset + priv->modulus - 1 < priv->offset)
 		return -EOVERFLOW;

 	return nft_validate_register_store(ctx, priv->dreg, NULL,
 					   NFT_DATA_VALUE, sizeof(u32));
 }

 static int nft_symhash_map_init(const struct nft_ctx *ctx,
 				const struct nft_expr *expr,
 				const struct nlattr * const tb[])
 {
 	struct nft_jhash *priv = nft_expr_priv(expr);
 	u8 genmask = nft_genmask_next(ctx->net);

 	nft_symhash_init(ctx, expr, tb);
 	priv->map = nft_set_lookup_global(ctx->net, ctx->table,
 					  tb[NFTA_HASH_SET_NAME],
 					  tb[NFTA_HASH_SET_ID], genmask);
 	return PTR_ERR_OR_ZERO(priv->map);
 }

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

 	if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg))
 		goto nla_put_failure;
 	if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
 		goto nla_put_failure;
 	if (!priv->autogen_seed &&
 	    nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
 		goto nla_put_failure;
 	if (priv->offset != 0)
 		if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
 			goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS)))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }

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

 	if (nft_jhash_dump(skb, expr) ||
 	    nla_put_string(skb, NFTA_HASH_SET_NAME, priv->map->name))
 		return -1;

 	return 0;
 }

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

 	if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
 		goto nla_put_failure;
 	if (priv->offset != 0)
 		if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
 			goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM)))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }

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

 	if (nft_symhash_dump(skb, expr) ||
 	    nla_put_string(skb, NFTA_HASH_SET_NAME, priv->map->name))
 		return -1;

 	return 0;
 }

 static struct nft_expr_type nft_hash_type;
 static const struct nft_expr_ops nft_jhash_ops = {
 	.type		= &nft_hash_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
 	.eval		= nft_jhash_eval,
 	.init		= nft_jhash_init,
 	.dump		= nft_jhash_dump,
 };

 static const struct nft_expr_ops nft_jhash_map_ops = {
 	.type		= &nft_hash_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
 	.eval		= nft_jhash_map_eval,
 	.init		= nft_jhash_map_init,
 	.dump		= nft_jhash_map_dump,
 };

 static const struct nft_expr_ops nft_symhash_ops = {
 	.type		= &nft_hash_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
 	.eval		= nft_symhash_eval,
 	.init		= nft_symhash_init,
 	.dump		= nft_symhash_dump,
 };

 static const struct nft_expr_ops nft_symhash_map_ops = {
 	.type		= &nft_hash_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
 	.eval		= nft_symhash_map_eval,
 	.init		= nft_symhash_map_init,
 	.dump		= nft_symhash_map_dump,
 };

 static const struct nft_expr_ops *
 nft_hash_select_ops(const struct nft_ctx *ctx,
 		    const struct nlattr * const tb[])
 {
 	u32 type;

 	if (!tb[NFTA_HASH_TYPE])
 		return &nft_jhash_ops;

 	type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
 	switch (type) {
 	case NFT_HASH_SYM:
 		if (tb[NFTA_HASH_SET_NAME])
 			return &nft_symhash_map_ops;
 		return &nft_symhash_ops;
 	case NFT_HASH_JENKINS:
 		if (tb[NFTA_HASH_SET_NAME])
 			return &nft_jhash_map_ops;
 		return &nft_jhash_ops;
 	default:
 		break;
 	}
 	return ERR_PTR(-EOPNOTSUPP);
 }

 static struct nft_expr_type nft_hash_type __read_mostly = {
 	.name		= "hash",
 	.select_ops	= nft_hash_select_ops,
 	.policy		= nft_hash_policy,
 	.maxattr	= NFTA_HASH_MAX,
 	.owner		= THIS_MODULE,
 };

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

 static void __exit nft_hash_module_exit(void)
 {
 	nft_unregister_expr(&nft_hash_type);
 }

 module_init(nft_hash_module_init);
 module_exit(nft_hash_module_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
 MODULE_ALIAS_NFT_EXPR("hash");
	/*
	* Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
	*
	* 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.
	*
	*/

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

	struct nft_jhash {
	enum nft_registers sreg:8;
	enum nft_registers dreg:8;
	u8 len;
	bool autogen_seed:1;
	u32 modulus;
	u32 seed;
	u32 offset;
	struct nft_set *map;
	};

	static void nft_jhash_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	struct nft_jhash *priv = nft_expr_priv(expr);
	const void *data = &regs->data[priv->sreg];
	u32 h;

	h = reciprocal_scale(jhash(data, priv->len, priv->seed),
	priv->modulus);

	regs->data[priv->dreg] = h + priv->offset;
	}

	static void nft_jhash_map_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	struct nft_jhash *priv = nft_expr_priv(expr);
	const void *data = &regs->data[priv->sreg];
	const struct nft_set *map = priv->map;
	const struct nft_set_ext *ext;
	u32 result;
	bool found;

	result = reciprocal_scale(jhash(data, priv->len, priv->seed),
	priv->modulus) + priv->offset;

	found = map->ops->lookup(nft_net(pkt), map, &result, &ext);
	if (!found)
	return;

	nft_data_copy(&regs->data[priv->dreg],
	nft_set_ext_data(ext), map->dlen);
	}

	struct nft_symhash {
	enum nft_registers dreg:8;
	u32 modulus;
	u32 offset;
	struct nft_set *map;
	};

	static void nft_symhash_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	struct nft_symhash *priv = nft_expr_priv(expr);
	struct sk_buff *skb = pkt->skb;
	u32 h;

	h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus);

	regs->data[priv->dreg] = h + priv->offset;
	}

	static void nft_symhash_map_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	struct nft_symhash *priv = nft_expr_priv(expr);
	struct sk_buff *skb = pkt->skb;
	const struct nft_set *map = priv->map;
	const struct nft_set_ext *ext;
	u32 result;
	bool found;

	result = reciprocal_scale(__skb_get_hash_symmetric(skb),
	priv->modulus) + priv->offset;

	found = map->ops->lookup(nft_net(pkt), map, &result, &ext);
	if (!found)
	return;

	nft_data_copy(&regs->data[priv->dreg],
	nft_set_ext_data(ext), map->dlen);
	}

	static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
	[NFTA_HASH_SREG] = { .type = NLA_U32 },
	[NFTA_HASH_DREG] = { .type = NLA_U32 },
	[NFTA_HASH_LEN] = { .type = NLA_U32 },
	[NFTA_HASH_MODULUS] = { .type = NLA_U32 },
	[NFTA_HASH_SEED] = { .type = NLA_U32 },
	[NFTA_HASH_OFFSET] = { .type = NLA_U32 },
	[NFTA_HASH_TYPE] = { .type = NLA_U32 },
	[NFTA_HASH_SET_NAME] = { .type = NLA_STRING,
	.len = NFT_SET_MAXNAMELEN - 1 },
	[NFTA_HASH_SET_ID] = { .type = NLA_U32 },
	};

	static int nft_jhash_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_jhash *priv = nft_expr_priv(expr);
	u32 len;
	int err;

	if (!tb[NFTA_HASH_SREG] \|\|
	!tb[NFTA_HASH_DREG] \|\|
	!tb[NFTA_HASH_LEN] \|\|
	!tb[NFTA_HASH_MODULUS])
	return -EINVAL;

	if (tb[NFTA_HASH_OFFSET])
	priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));

	priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]);
	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);

	err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
	if (err < 0)
	return err;
	if (len == 0)
	return -ERANGE;

	priv->len = len;

	priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
	if (priv->modulus < 1)
	return -ERANGE;

	if (priv->offset + priv->modulus - 1 < priv->offset)
	return -EOVERFLOW;

	if (tb[NFTA_HASH_SEED]) {
	priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
	} else {
	priv->autogen_seed = true;
	get_random_bytes(&priv->seed, sizeof(priv->seed));
	}

	return nft_validate_register_load(priv->sreg, len) &&
	nft_validate_register_store(ctx, priv->dreg, NULL,
	NFT_DATA_VALUE, sizeof(u32));
	}

	static int nft_jhash_map_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_jhash *priv = nft_expr_priv(expr);
	u8 genmask = nft_genmask_next(ctx->net);

	nft_jhash_init(ctx, expr, tb);
	priv->map = nft_set_lookup_global(ctx->net, ctx->table,
	tb[NFTA_HASH_SET_NAME],
	tb[NFTA_HASH_SET_ID], genmask);
	return PTR_ERR_OR_ZERO(priv->map);
	}

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

	if (!tb[NFTA_HASH_DREG] \|\|
	!tb[NFTA_HASH_MODULUS])
	return -EINVAL;

	if (tb[NFTA_HASH_OFFSET])
	priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));

	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);

	priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
	if (priv->modulus <= 1)
	return -ERANGE;

	if (priv->offset + priv->modulus - 1 < priv->offset)
	return -EOVERFLOW;

	return nft_validate_register_store(ctx, priv->dreg, NULL,
	NFT_DATA_VALUE, sizeof(u32));
	}

	static int nft_symhash_map_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_jhash *priv = nft_expr_priv(expr);
	u8 genmask = nft_genmask_next(ctx->net);

	nft_symhash_init(ctx, expr, tb);
	priv->map = nft_set_lookup_global(ctx->net, ctx->table,
	tb[NFTA_HASH_SET_NAME],
	tb[NFTA_HASH_SET_ID], genmask);
	return PTR_ERR_OR_ZERO(priv->map);
	}

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

	if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg))
	goto nla_put_failure;
	if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
	goto nla_put_failure;
	if (!priv->autogen_seed &&
	nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
	goto nla_put_failure;
	if (priv->offset != 0)
	if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS)))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}

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

	if (nft_jhash_dump(skb, expr) \|\|
	nla_put_string(skb, NFTA_HASH_SET_NAME, priv->map->name))
	return -1;

	return 0;
	}

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

	if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
	goto nla_put_failure;
	if (priv->offset != 0)
	if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM)))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}

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

	if (nft_symhash_dump(skb, expr) \|\|
	nla_put_string(skb, NFTA_HASH_SET_NAME, priv->map->name))
	return -1;

	return 0;
	}

	static struct nft_expr_type nft_hash_type;
	static const struct nft_expr_ops nft_jhash_ops = {
	.type = &nft_hash_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
	.eval = nft_jhash_eval,
	.init = nft_jhash_init,
	.dump = nft_jhash_dump,
	};

	static const struct nft_expr_ops nft_jhash_map_ops = {
	.type = &nft_hash_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
	.eval = nft_jhash_map_eval,
	.init = nft_jhash_map_init,
	.dump = nft_jhash_map_dump,
	};

	static const struct nft_expr_ops nft_symhash_ops = {
	.type = &nft_hash_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
	.eval = nft_symhash_eval,
	.init = nft_symhash_init,
	.dump = nft_symhash_dump,
	};

	static const struct nft_expr_ops nft_symhash_map_ops = {
	.type = &nft_hash_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
	.eval = nft_symhash_map_eval,
	.init = nft_symhash_map_init,
	.dump = nft_symhash_map_dump,
	};

	static const struct nft_expr_ops *
	nft_hash_select_ops(const struct nft_ctx *ctx,
	const struct nlattr * const tb[])
	{
	u32 type;

	if (!tb[NFTA_HASH_TYPE])
	return &nft_jhash_ops;

	type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
	switch (type) {
	case NFT_HASH_SYM:
	if (tb[NFTA_HASH_SET_NAME])
	return &nft_symhash_map_ops;
	return &nft_symhash_ops;
	case NFT_HASH_JENKINS:
	if (tb[NFTA_HASH_SET_NAME])
	return &nft_jhash_map_ops;
	return &nft_jhash_ops;
	default:
	break;
	}
	return ERR_PTR(-EOPNOTSUPP);
	}

	static struct nft_expr_type nft_hash_type __read_mostly = {
	.name = "hash",
	.select_ops = nft_hash_select_ops,
	.policy = nft_hash_policy,
	.maxattr = NFTA_HASH_MAX,
	.owner = THIS_MODULE,
	};

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

	static void __exit nft_hash_module_exit(void)
	{
	nft_unregister_expr(&nft_hash_type);
	}

	module_init(nft_hash_module_init);
	module_exit(nft_hash_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
	MODULE_ALIAS_NFT_EXPR("hash");