[linux-2.6-block.git] / net / netfilter / nft_hash.c

/*
 * 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;
	u32			modulus;
	u32			seed;
	u32			offset;
};

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;
}

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

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 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 },
};

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
		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_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_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 (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_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 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_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_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:
		return &nft_symhash_ops;
	case NFT_HASH_JENKINS:
		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");
Commit	Line	Data
cb1b69b0 LGL	1	/*
	2	* Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
	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	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/init.h>
	12	#include <linux/module.h>
	13	#include <linux/netlink.h>
	14	#include <linux/netfilter.h>
	15	#include <linux/netfilter/nf_tables.h>
	16	#include <net/netfilter/nf_tables.h>
	17	#include <net/netfilter/nf_tables_core.h>
	18	#include <linux/jhash.h>
	19
511040ee	20	struct nft_jhash {
cb1b69b0 LGL	21	enum nft_registers sreg:8;
	22	enum nft_registers dreg:8;
	23	u8 len;
	24	u32 modulus;
	25	u32 seed;
70ca767e	26	u32 offset;
cb1b69b0 LGL	27	};
cb1b69b0 LGL	28
511040ee LGL	29	static void nft_jhash_eval(const struct nft_expr *expr,
	30	struct nft_regs *regs,
	31	const struct nft_pktinfo *pkt)
cb1b69b0	32	{
511040ee	33	struct nft_jhash *priv = nft_expr_priv(expr);
cb1b69b0	34	const void *data = &regs->data[priv->sreg];
70ca767e	35	u32 h;
cb1b69b0	36
70ca767e LGL	37	h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus);
70ca767e LGL	38	regs->data[priv->dreg] = h + priv->offset;
cb1b69b0 LGL	39	}
cb1b69b0 LGL	40
3206cade LGL	41	struct nft_symhash {
	42	enum nft_registers dreg:8;
	43	u32 modulus;
	44	u32 offset;
	45	};
	46
	47	static void nft_symhash_eval(const struct nft_expr *expr,
	48	struct nft_regs *regs,
	49	const struct nft_pktinfo *pkt)
	50	{
	51	struct nft_symhash *priv = nft_expr_priv(expr);
	52	struct sk_buff *skb = pkt->skb;
	53	u32 h;
	54
	55	h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus);
	56
	57	regs->data[priv->dreg] = h + priv->offset;
	58	}
	59
a5e57336	60	static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
cb1b69b0 LGL	61	[NFTA_HASH_SREG] = { .type = NLA_U32 },
	62	[NFTA_HASH_DREG] = { .type = NLA_U32 },
	63	[NFTA_HASH_LEN] = { .type = NLA_U32 },
	64	[NFTA_HASH_MODULUS] = { .type = NLA_U32 },
	65	[NFTA_HASH_SEED] = { .type = NLA_U32 },
5751e175	66	[NFTA_HASH_OFFSET] = { .type = NLA_U32 },
3206cade	67	[NFTA_HASH_TYPE] = { .type = NLA_U32 },
cb1b69b0 LGL	68	};
cb1b69b0 LGL	69
511040ee LGL	70	static int nft_jhash_init(const struct nft_ctx *ctx,
	71	const struct nft_expr *expr,
	72	const struct nlattr * const tb[])
cb1b69b0	73	{
511040ee	74	struct nft_jhash *priv = nft_expr_priv(expr);
cb1b69b0	75	u32 len;
abd66e9f	76	int err;
cb1b69b0 LGL	77
	78	if (!tb[NFTA_HASH_SREG] \|\|
	79	!tb[NFTA_HASH_DREG] \|\|
	80	!tb[NFTA_HASH_LEN] \|\|
cb1b69b0 LGL	81	!tb[NFTA_HASH_MODULUS])
	82	return -EINVAL;
	83
70ca767e LGL	84	if (tb[NFTA_HASH_OFFSET])
	85	priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
	86
cb1b69b0 LGL	87	priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]);
	88	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);
	89
abd66e9f LGL	90	err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
	91	if (err < 0)
	92	return err;
	93	if (len == 0)
cb1b69b0 LGL	94	return -ERANGE;
	95
	96	priv->len = len;
	97
	98	priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
	99	if (priv->modulus <= 1)
	100	return -ERANGE;
	101
14e2dee0	102	if (priv->offset + priv->modulus - 1 < priv->offset)
70ca767e LGL	103	return -EOVERFLOW;
70ca767e LGL	104
f86dab3a PNA	105	if (tb[NFTA_HASH_SEED])
	106	priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
	107	else
	108	get_random_bytes(&priv->seed, sizeof(priv->seed));
cb1b69b0 LGL	109
	110	return nft_validate_register_load(priv->sreg, len) &&
	111	nft_validate_register_store(ctx, priv->dreg, NULL,
	112	NFT_DATA_VALUE, sizeof(u32));
	113	}
	114
3206cade LGL	115	static int nft_symhash_init(const struct nft_ctx *ctx,
	116	const struct nft_expr *expr,
	117	const struct nlattr * const tb[])
	118	{
	119	struct nft_symhash *priv = nft_expr_priv(expr);
	120
	121	if (!tb[NFTA_HASH_DREG] \|\|
	122	!tb[NFTA_HASH_MODULUS])
	123	return -EINVAL;
	124
	125	if (tb[NFTA_HASH_OFFSET])
	126	priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
	127
	128	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);
	129
	130	priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
	131	if (priv->modulus <= 1)
	132	return -ERANGE;
	133
	134	if (priv->offset + priv->modulus - 1 < priv->offset)
	135	return -EOVERFLOW;
	136
	137	return nft_validate_register_store(ctx, priv->dreg, NULL,
	138	NFT_DATA_VALUE, sizeof(u32));
	139	}
	140
511040ee LGL	141	static int nft_jhash_dump(struct sk_buff *skb,
511040ee LGL	142	const struct nft_expr *expr)
cb1b69b0	143	{
511040ee	144	const struct nft_jhash *priv = nft_expr_priv(expr);
cb1b69b0 LGL	145
	146	if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg))
	147	goto nla_put_failure;
	148	if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
	149	goto nla_put_failure;
7073b16f	150	if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
cb1b69b0	151	goto nla_put_failure;
7073b16f	152	if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
cb1b69b0	153	goto nla_put_failure;
7073b16f	154	if (nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
cb1b69b0	155	goto nla_put_failure;
70ca767e LGL	156	if (priv->offset != 0)
	157	if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
	158	goto nla_put_failure;
3206cade LGL	159	if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS)))
	160	goto nla_put_failure;
	161	return 0;
	162
	163	nla_put_failure:
	164	return -1;
	165	}
	166
	167	static int nft_symhash_dump(struct sk_buff *skb,
	168	const struct nft_expr *expr)
	169	{
	170	const struct nft_symhash *priv = nft_expr_priv(expr);
	171
	172	if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
	173	goto nla_put_failure;
	174	if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
	175	goto nla_put_failure;
	176	if (priv->offset != 0)
	177	if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
	178	goto nla_put_failure;
	179	if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM)))
	180	goto nla_put_failure;
cb1b69b0 LGL	181	return 0;
	182
	183	nla_put_failure:
	184	return -1;
	185	}
	186
	187	static struct nft_expr_type nft_hash_type;
511040ee	188	static const struct nft_expr_ops nft_jhash_ops = {
cb1b69b0	189	.type = &nft_hash_type,
511040ee LGL	190	.size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
	191	.eval = nft_jhash_eval,
	192	.init = nft_jhash_init,
	193	.dump = nft_jhash_dump,
cb1b69b0 LGL	194	};
cb1b69b0 LGL	195
3206cade LGL	196	static const struct nft_expr_ops nft_symhash_ops = {
	197	.type = &nft_hash_type,
	198	.size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
	199	.eval = nft_symhash_eval,
	200	.init = nft_symhash_init,
	201	.dump = nft_symhash_dump,
	202	};
	203
	204	static const struct nft_expr_ops *
	205	nft_hash_select_ops(const struct nft_ctx *ctx,
	206	const struct nlattr * const tb[])
	207	{
	208	u32 type;
	209
	210	if (!tb[NFTA_HASH_TYPE])
	211	return &nft_jhash_ops;
	212
	213	type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
	214	switch (type) {
	215	case NFT_HASH_SYM:
	216	return &nft_symhash_ops;
	217	case NFT_HASH_JENKINS:
	218	return &nft_jhash_ops;
	219	default:
	220	break;
	221	}
	222	return ERR_PTR(-EOPNOTSUPP);
	223	}
	224
cb1b69b0 LGL	225	static struct nft_expr_type nft_hash_type __read_mostly = {
cb1b69b0 LGL	226	.name = "hash",
3206cade	227	.select_ops = &nft_hash_select_ops,
cb1b69b0 LGL	228	.policy = nft_hash_policy,
	229	.maxattr = NFTA_HASH_MAX,
	230	.owner = THIS_MODULE,
	231	};
	232
	233	static int __init nft_hash_module_init(void)
	234	{
	235	return nft_register_expr(&nft_hash_type);
	236	}
	237
	238	static void __exit nft_hash_module_exit(void)
	239	{
	240	nft_unregister_expr(&nft_hash_type);
	241	}
	242
	243	module_init(nft_hash_module_init);
	244	module_exit(nft_hash_module_exit);
	245
	246	MODULE_LICENSE("GPL");
	247	MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
	248	MODULE_ALIAS_NFT_EXPR("hash");