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

/*
 * Copyright (c) 2016 Laura Garcia <[email protected]>
 *
 * 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;
};

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 {
		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_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 (!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_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 <[email protected]>");
MODULE_ALIAS_NFT_EXPR("hash");
Commit	Line	Data
cb1b69b0 LGL	1	/*
	2	* Copyright (c) 2016 Laura Garcia <[email protected]>
	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;
79e09ef9	24	bool autogen_seed:1;
cb1b69b0 LGL	25	u32 modulus;
cb1b69b0 LGL	26	u32 seed;
70ca767e	27	u32 offset;
cb1b69b0 LGL	28	};
cb1b69b0 LGL	29
511040ee LGL	30	static void nft_jhash_eval(const struct nft_expr *expr,
	31	struct nft_regs *regs,
	32	const struct nft_pktinfo *pkt)
cb1b69b0	33	{
511040ee	34	struct nft_jhash *priv = nft_expr_priv(expr);
cb1b69b0	35	const void *data = &regs->data[priv->sreg];
70ca767e	36	u32 h;
cb1b69b0	37
70ca767e LGL	38	h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus);
70ca767e LGL	39	regs->data[priv->dreg] = h + priv->offset;
cb1b69b0 LGL	40	}
cb1b69b0 LGL	41
3206cade LGL	42	struct nft_symhash {
	43	enum nft_registers dreg:8;
	44	u32 modulus;
	45	u32 offset;
	46	};
	47
	48	static void nft_symhash_eval(const struct nft_expr *expr,
	49	struct nft_regs *regs,
	50	const struct nft_pktinfo *pkt)
	51	{
	52	struct nft_symhash *priv = nft_expr_priv(expr);
	53	struct sk_buff *skb = pkt->skb;
	54	u32 h;
	55
	56	h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus);
	57
	58	regs->data[priv->dreg] = h + priv->offset;
	59	}
	60
a5e57336	61	static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
cb1b69b0 LGL	62	[NFTA_HASH_SREG] = { .type = NLA_U32 },
	63	[NFTA_HASH_DREG] = { .type = NLA_U32 },
	64	[NFTA_HASH_LEN] = { .type = NLA_U32 },
	65	[NFTA_HASH_MODULUS] = { .type = NLA_U32 },
	66	[NFTA_HASH_SEED] = { .type = NLA_U32 },
5751e175	67	[NFTA_HASH_OFFSET] = { .type = NLA_U32 },
3206cade	68	[NFTA_HASH_TYPE] = { .type = NLA_U32 },
cb1b69b0 LGL	69	};
cb1b69b0 LGL	70
511040ee LGL	71	static int nft_jhash_init(const struct nft_ctx *ctx,
	72	const struct nft_expr *expr,
	73	const struct nlattr * const tb[])
cb1b69b0	74	{
511040ee	75	struct nft_jhash *priv = nft_expr_priv(expr);
cb1b69b0	76	u32 len;
abd66e9f	77	int err;
cb1b69b0 LGL	78
	79	if (!tb[NFTA_HASH_SREG] \|\|
	80	!tb[NFTA_HASH_DREG] \|\|
	81	!tb[NFTA_HASH_LEN] \|\|
cb1b69b0 LGL	82	!tb[NFTA_HASH_MODULUS])
	83	return -EINVAL;
	84
70ca767e LGL	85	if (tb[NFTA_HASH_OFFSET])
	86	priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
	87
cb1b69b0 LGL	88	priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]);
	89	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);
	90
abd66e9f LGL	91	err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
	92	if (err < 0)
	93	return err;
	94	if (len == 0)
cb1b69b0 LGL	95	return -ERANGE;
	96
	97	priv->len = len;
	98
	99	priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
	100	if (priv->modulus <= 1)
	101	return -ERANGE;
	102
14e2dee0	103	if (priv->offset + priv->modulus - 1 < priv->offset)
70ca767e LGL	104	return -EOVERFLOW;
70ca767e LGL	105
79e09ef9	106	if (tb[NFTA_HASH_SEED]) {
f86dab3a	107	priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
79e09ef9 LZ	108	} else {
79e09ef9 LZ	109	priv->autogen_seed = true;
f86dab3a	110	get_random_bytes(&priv->seed, sizeof(priv->seed));
79e09ef9	111	}
cb1b69b0 LGL	112
	113	return nft_validate_register_load(priv->sreg, len) &&
	114	nft_validate_register_store(ctx, priv->dreg, NULL,
	115	NFT_DATA_VALUE, sizeof(u32));
	116	}
	117
3206cade LGL	118	static int nft_symhash_init(const struct nft_ctx *ctx,
	119	const struct nft_expr *expr,
	120	const struct nlattr * const tb[])
	121	{
	122	struct nft_symhash *priv = nft_expr_priv(expr);
	123
	124	if (!tb[NFTA_HASH_DREG] \|\|
	125	!tb[NFTA_HASH_MODULUS])
	126	return -EINVAL;
	127
	128	if (tb[NFTA_HASH_OFFSET])
	129	priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
	130
	131	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);
	132
	133	priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
	134	if (priv->modulus <= 1)
	135	return -ERANGE;
	136
	137	if (priv->offset + priv->modulus - 1 < priv->offset)
	138	return -EOVERFLOW;
	139
	140	return nft_validate_register_store(ctx, priv->dreg, NULL,
	141	NFT_DATA_VALUE, sizeof(u32));
	142	}
	143
511040ee LGL	144	static int nft_jhash_dump(struct sk_buff *skb,
511040ee LGL	145	const struct nft_expr *expr)
cb1b69b0	146	{
511040ee	147	const struct nft_jhash *priv = nft_expr_priv(expr);
cb1b69b0 LGL	148
	149	if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg))
	150	goto nla_put_failure;
	151	if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
	152	goto nla_put_failure;
7073b16f	153	if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
cb1b69b0	154	goto nla_put_failure;
7073b16f	155	if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
cb1b69b0	156	goto nla_put_failure;
79e09ef9 LZ	157	if (!priv->autogen_seed &&
79e09ef9 LZ	158	nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
cb1b69b0	159	goto nla_put_failure;
70ca767e LGL	160	if (priv->offset != 0)
	161	if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
	162	goto nla_put_failure;
3206cade LGL	163	if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS)))
	164	goto nla_put_failure;
	165	return 0;
	166
	167	nla_put_failure:
	168	return -1;
	169	}
	170
	171	static int nft_symhash_dump(struct sk_buff *skb,
	172	const struct nft_expr *expr)
	173	{
	174	const struct nft_symhash *priv = nft_expr_priv(expr);
	175
	176	if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
	177	goto nla_put_failure;
	178	if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
	179	goto nla_put_failure;
	180	if (priv->offset != 0)
	181	if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
	182	goto nla_put_failure;
	183	if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM)))
	184	goto nla_put_failure;
cb1b69b0 LGL	185	return 0;
	186
	187	nla_put_failure:
	188	return -1;
	189	}
	190
	191	static struct nft_expr_type nft_hash_type;
511040ee	192	static const struct nft_expr_ops nft_jhash_ops = {
cb1b69b0	193	.type = &nft_hash_type,
511040ee LGL	194	.size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
	195	.eval = nft_jhash_eval,
	196	.init = nft_jhash_init,
	197	.dump = nft_jhash_dump,
cb1b69b0 LGL	198	};
cb1b69b0 LGL	199
3206cade LGL	200	static const struct nft_expr_ops nft_symhash_ops = {
	201	.type = &nft_hash_type,
	202	.size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
	203	.eval = nft_symhash_eval,
	204	.init = nft_symhash_init,
	205	.dump = nft_symhash_dump,
	206	};
	207
	208	static const struct nft_expr_ops *
	209	nft_hash_select_ops(const struct nft_ctx *ctx,
	210	const struct nlattr * const tb[])
	211	{
	212	u32 type;
	213
	214	if (!tb[NFTA_HASH_TYPE])
	215	return &nft_jhash_ops;
	216
	217	type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
	218	switch (type) {
	219	case NFT_HASH_SYM:
	220	return &nft_symhash_ops;
	221	case NFT_HASH_JENKINS:
	222	return &nft_jhash_ops;
	223	default:
	224	break;
	225	}
	226	return ERR_PTR(-EOPNOTSUPP);
	227	}
	228
cb1b69b0 LGL	229	static struct nft_expr_type nft_hash_type __read_mostly = {
cb1b69b0 LGL	230	.name = "hash",
d4ef3835	231	.select_ops = nft_hash_select_ops,
cb1b69b0 LGL	232	.policy = nft_hash_policy,
	233	.maxattr = NFTA_HASH_MAX,
	234	.owner = THIS_MODULE,
	235	};
	236
	237	static int __init nft_hash_module_init(void)
	238	{
	239	return nft_register_expr(&nft_hash_type);
	240	}
	241
	242	static void __exit nft_hash_module_exit(void)
	243	{
	244	nft_unregister_expr(&nft_hash_type);
	245	}
	246
	247	module_init(nft_hash_module_init);
	248	module_exit(nft_hash_module_exit);
	249
	250	MODULE_LICENSE("GPL");
	251	MODULE_AUTHOR("Laura Garcia <[email protected]>");
	252	MODULE_ALIAS_NFT_EXPR("hash");