[linux-2.6-block.git] / net / netfilter / nft_numgen.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 <linux/static_key.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>

static DEFINE_PER_CPU(struct rnd_state, nft_numgen_prandom_state);

struct nft_ng_inc {
	enum nft_registers      dreg:8;
	u32			modulus;
	atomic_t		counter;
	u32			offset;
	struct nft_set		*map;
};

static u32 nft_ng_inc_gen(struct nft_ng_inc *priv)
{
	u32 nval, oval;

	do {
		oval = atomic_read(&priv->counter);
		nval = (oval + 1 < priv->modulus) ? oval + 1 : 0;
	} while (atomic_cmpxchg(&priv->counter, oval, nval) != oval);

	return nval + priv->offset;
}

static void nft_ng_inc_eval(const struct nft_expr *expr,
			    struct nft_regs *regs,
			    const struct nft_pktinfo *pkt)
{
	struct nft_ng_inc *priv = nft_expr_priv(expr);

	regs->data[priv->dreg] = nft_ng_inc_gen(priv);
}

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

	result = nft_ng_inc_gen(priv);
	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_ng_policy[NFTA_NG_MAX + 1] = {
	[NFTA_NG_DREG]		= { .type = NLA_U32 },
	[NFTA_NG_MODULUS]	= { .type = NLA_U32 },
	[NFTA_NG_TYPE]		= { .type = NLA_U32 },
	[NFTA_NG_OFFSET]	= { .type = NLA_U32 },
	[NFTA_NG_SET_NAME]	= { .type = NLA_STRING,
				    .len = NFT_SET_MAXNAMELEN - 1 },
	[NFTA_NG_SET_ID]	= { .type = NLA_U32 },
};

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

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

	priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
	if (priv->modulus == 0)
		return -ERANGE;

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

	priv->dreg = nft_parse_register(tb[NFTA_NG_DREG]);
	atomic_set(&priv->counter, priv->modulus - 1);

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

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

	nft_ng_inc_init(ctx, expr, tb);

	priv->map = nft_set_lookup_global(ctx->net, ctx->table,
					  tb[NFTA_NG_SET_NAME],
					  tb[NFTA_NG_SET_ID], genmask);

	if (IS_ERR(priv->map))
		return PTR_ERR(priv->map);

	return 0;
}

static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,
		       u32 modulus, enum nft_ng_types type, u32 offset)
{
	if (nft_dump_register(skb, NFTA_NG_DREG, dreg))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_NG_MODULUS, htonl(modulus)))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_NG_TYPE, htonl(type)))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_NG_OFFSET, htonl(offset)))
		goto nla_put_failure;

	return 0;

nla_put_failure:
	return -1;
}

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

	return nft_ng_dump(skb, priv->dreg, priv->modulus, NFT_NG_INCREMENTAL,
			   priv->offset);
}

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

	if (nft_ng_dump(skb, priv->dreg, priv->modulus,
			NFT_NG_INCREMENTAL, priv->offset) ||
	    nla_put_string(skb, NFTA_NG_SET_NAME, priv->map->name))
		goto nla_put_failure;

	return 0;

nla_put_failure:
	return -1;
}

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

static void nft_ng_random_eval(const struct nft_expr *expr,
			       struct nft_regs *regs,
			       const struct nft_pktinfo *pkt)
{
	struct nft_ng_random *priv = nft_expr_priv(expr);
	struct rnd_state *state = this_cpu_ptr(&nft_numgen_prandom_state);
	u32 val;

	val = reciprocal_scale(prandom_u32_state(state), priv->modulus);
	regs->data[priv->dreg] = val + priv->offset;
}

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

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

	priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
	if (priv->modulus == 0)
		return -ERANGE;

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

	prandom_init_once(&nft_numgen_prandom_state);

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

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

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

	return nft_ng_dump(skb, priv->dreg, priv->modulus, NFT_NG_RANDOM,
			   priv->offset);
}

static struct nft_expr_type nft_ng_type;
static const struct nft_expr_ops nft_ng_inc_ops = {
	.type		= &nft_ng_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_ng_inc)),
	.eval		= nft_ng_inc_eval,
	.init		= nft_ng_inc_init,
	.dump		= nft_ng_inc_dump,
};

static const struct nft_expr_ops nft_ng_inc_map_ops = {
	.type		= &nft_ng_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_ng_inc)),
	.eval		= nft_ng_inc_map_eval,
	.init		= nft_ng_inc_map_init,
	.dump		= nft_ng_inc_map_dump,
};

static const struct nft_expr_ops nft_ng_random_ops = {
	.type		= &nft_ng_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_ng_random)),
	.eval		= nft_ng_random_eval,
	.init		= nft_ng_random_init,
	.dump		= nft_ng_random_dump,
};

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

	if (!tb[NFTA_NG_DREG]	 ||
	    !tb[NFTA_NG_MODULUS] ||
	    !tb[NFTA_NG_TYPE])
		return ERR_PTR(-EINVAL);

	type = ntohl(nla_get_be32(tb[NFTA_NG_TYPE]));

	switch (type) {
	case NFT_NG_INCREMENTAL:
		if (tb[NFTA_NG_SET_NAME])
			return &nft_ng_inc_map_ops;
		return &nft_ng_inc_ops;
	case NFT_NG_RANDOM:
		return &nft_ng_random_ops;
	}

	return ERR_PTR(-EINVAL);
}

static struct nft_expr_type nft_ng_type __read_mostly = {
	.name		= "numgen",
	.select_ops	= nft_ng_select_ops,
	.policy		= nft_ng_policy,
	.maxattr	= NFTA_NG_MAX,
	.owner		= THIS_MODULE,
};

static int __init nft_ng_module_init(void)
{
	return nft_register_expr(&nft_ng_type);
}

static void __exit nft_ng_module_exit(void)
{
	nft_unregister_expr(&nft_ng_type);
}

module_init(nft_ng_module_init);
module_exit(nft_ng_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
MODULE_ALIAS_NFT_EXPR("numgen");
Commit	Line	Data
91dbc6be 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 <linux/static_key.h>
	17	#include <net/netfilter/nf_tables.h>
	18	#include <net/netfilter/nf_tables_core.h>
	19
	20	static DEFINE_PER_CPU(struct rnd_state, nft_numgen_prandom_state);
	21
	22	struct nft_ng_inc {
	23	enum nft_registers dreg:8;
0d9932b2	24	u32 modulus;
91dbc6be	25	atomic_t counter;
2b03bf73	26	u32 offset;
d734a288	27	struct nft_set *map;
91dbc6be LGL	28	};
91dbc6be LGL	29
d734a288	30	static u32 nft_ng_inc_gen(struct nft_ng_inc *priv)
91dbc6be	31	{
91dbc6be LGL	32	u32 nval, oval;
	33
	34	do {
	35	oval = atomic_read(&priv->counter);
0d9932b2	36	nval = (oval + 1 < priv->modulus) ? oval + 1 : 0;
91dbc6be LGL	37	} while (atomic_cmpxchg(&priv->counter, oval, nval) != oval);
91dbc6be LGL	38
d734a288 LGL	39	return nval + priv->offset;
	40	}
	41
	42	static void nft_ng_inc_eval(const struct nft_expr *expr,
	43	struct nft_regs *regs,
	44	const struct nft_pktinfo *pkt)
	45	{
	46	struct nft_ng_inc *priv = nft_expr_priv(expr);
	47
	48	regs->data[priv->dreg] = nft_ng_inc_gen(priv);
	49	}
	50
	51	static void nft_ng_inc_map_eval(const struct nft_expr *expr,
	52	struct nft_regs *regs,
	53	const struct nft_pktinfo *pkt)
	54	{
	55	struct nft_ng_inc *priv = nft_expr_priv(expr);
	56	const struct nft_set *map = priv->map;
	57	const struct nft_set_ext *ext;
	58	u32 result;
	59	bool found;
	60
	61	result = nft_ng_inc_gen(priv);
	62	found = map->ops->lookup(nft_net(pkt), map, &result, &ext);
	63
	64	if (!found)
	65	return;
	66
	67	nft_data_copy(&regs->data[priv->dreg],
	68	nft_set_ext_data(ext), map->dlen);
91dbc6be LGL	69	}
	70
	71	static const struct nla_policy nft_ng_policy[NFTA_NG_MAX + 1] = {
	72	[NFTA_NG_DREG] = { .type = NLA_U32 },
0d9932b2	73	[NFTA_NG_MODULUS] = { .type = NLA_U32 },
91dbc6be	74	[NFTA_NG_TYPE] = { .type = NLA_U32 },
2b03bf73	75	[NFTA_NG_OFFSET] = { .type = NLA_U32 },
d734a288 LGL	76	[NFTA_NG_SET_NAME] = { .type = NLA_STRING,
	77	.len = NFT_SET_MAXNAMELEN - 1 },
	78	[NFTA_NG_SET_ID] = { .type = NLA_U32 },
91dbc6be LGL	79	};
	80
	81	static int nft_ng_inc_init(const struct nft_ctx *ctx,
	82	const struct nft_expr *expr,
	83	const struct nlattr * const tb[])
	84	{
	85	struct nft_ng_inc *priv = nft_expr_priv(expr);
	86
2b03bf73 LGL	87	if (tb[NFTA_NG_OFFSET])
	88	priv->offset = ntohl(nla_get_be32(tb[NFTA_NG_OFFSET]));
	89
0d9932b2 LGL	90	priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
0d9932b2 LGL	91	if (priv->modulus == 0)
91dbc6be LGL	92	return -ERANGE;
91dbc6be LGL	93
2b03bf73 LGL	94	if (priv->offset + priv->modulus - 1 < priv->offset)
	95	return -EOVERFLOW;
	96
91dbc6be	97	priv->dreg = nft_parse_register(tb[NFTA_NG_DREG]);
0ecba4d9	98	atomic_set(&priv->counter, priv->modulus - 1);
91dbc6be LGL	99
	100	return nft_validate_register_store(ctx, priv->dreg, NULL,
	101	NFT_DATA_VALUE, sizeof(u32));
	102	}
	103
d734a288 LGL	104	static int nft_ng_inc_map_init(const struct nft_ctx *ctx,
	105	const struct nft_expr *expr,
	106	const struct nlattr * const tb[])
	107	{
	108	struct nft_ng_inc *priv = nft_expr_priv(expr);
	109	u8 genmask = nft_genmask_next(ctx->net);
	110
	111	nft_ng_inc_init(ctx, expr, tb);
	112
	113	priv->map = nft_set_lookup_global(ctx->net, ctx->table,
	114	tb[NFTA_NG_SET_NAME],
	115	tb[NFTA_NG_SET_ID], genmask);
	116
	117	if (IS_ERR(priv->map))
	118	return PTR_ERR(priv->map);
	119
	120	return 0;
	121	}
	122
91dbc6be	123	static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,
2b03bf73	124	u32 modulus, enum nft_ng_types type, u32 offset)
91dbc6be LGL	125	{
	126	if (nft_dump_register(skb, NFTA_NG_DREG, dreg))
	127	goto nla_put_failure;
0d9932b2	128	if (nla_put_be32(skb, NFTA_NG_MODULUS, htonl(modulus)))
91dbc6be	129	goto nla_put_failure;
7073b16f	130	if (nla_put_be32(skb, NFTA_NG_TYPE, htonl(type)))
91dbc6be	131	goto nla_put_failure;
2b03bf73 LGL	132	if (nla_put_be32(skb, NFTA_NG_OFFSET, htonl(offset)))
2b03bf73 LGL	133	goto nla_put_failure;
91dbc6be LGL	134
	135	return 0;
	136
	137	nla_put_failure:
	138	return -1;
	139	}
	140
	141	static int nft_ng_inc_dump(struct sk_buff skb, const struct nft_expr expr)
	142	{
	143	const struct nft_ng_inc *priv = nft_expr_priv(expr);
	144
2b03bf73 LGL	145	return nft_ng_dump(skb, priv->dreg, priv->modulus, NFT_NG_INCREMENTAL,
2b03bf73 LGL	146	priv->offset);
91dbc6be LGL	147	}
91dbc6be LGL	148
d734a288 LGL	149	static int nft_ng_inc_map_dump(struct sk_buff *skb,
	150	const struct nft_expr *expr)
	151	{
	152	const struct nft_ng_inc *priv = nft_expr_priv(expr);
	153
	154	if (nft_ng_dump(skb, priv->dreg, priv->modulus,
	155	NFT_NG_INCREMENTAL, priv->offset) \|\|
	156	nla_put_string(skb, NFTA_NG_SET_NAME, priv->map->name))
	157	goto nla_put_failure;
	158
	159	return 0;
	160
	161	nla_put_failure:
	162	return -1;
	163	}
	164
91dbc6be LGL	165	struct nft_ng_random {
91dbc6be LGL	166	enum nft_registers dreg:8;
0d9932b2	167	u32 modulus;
2b03bf73	168	u32 offset;
91dbc6be LGL	169	};
	170
	171	static void nft_ng_random_eval(const struct nft_expr *expr,
	172	struct nft_regs *regs,
	173	const struct nft_pktinfo *pkt)
	174	{
	175	struct nft_ng_random *priv = nft_expr_priv(expr);
	176	struct rnd_state *state = this_cpu_ptr(&nft_numgen_prandom_state);
2b03bf73	177	u32 val;
91dbc6be	178
2b03bf73 LGL	179	val = reciprocal_scale(prandom_u32_state(state), priv->modulus);
2b03bf73 LGL	180	regs->data[priv->dreg] = val + priv->offset;
91dbc6be LGL	181	}
	182
	183	static int nft_ng_random_init(const struct nft_ctx *ctx,
	184	const struct nft_expr *expr,
	185	const struct nlattr * const tb[])
	186	{
	187	struct nft_ng_random *priv = nft_expr_priv(expr);
	188
2b03bf73 LGL	189	if (tb[NFTA_NG_OFFSET])
	190	priv->offset = ntohl(nla_get_be32(tb[NFTA_NG_OFFSET]));
	191
0d9932b2 LGL	192	priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
0d9932b2 LGL	193	if (priv->modulus == 0)
91dbc6be LGL	194	return -ERANGE;
91dbc6be LGL	195
2b03bf73 LGL	196	if (priv->offset + priv->modulus - 1 < priv->offset)
	197	return -EOVERFLOW;
	198
91dbc6be LGL	199	prandom_init_once(&nft_numgen_prandom_state);
	200
	201	priv->dreg = nft_parse_register(tb[NFTA_NG_DREG]);
	202
	203	return nft_validate_register_store(ctx, priv->dreg, NULL,
	204	NFT_DATA_VALUE, sizeof(u32));
	205	}
	206
	207	static int nft_ng_random_dump(struct sk_buff skb, const struct nft_expr expr)
	208	{
	209	const struct nft_ng_random *priv = nft_expr_priv(expr);
	210
2b03bf73 LGL	211	return nft_ng_dump(skb, priv->dreg, priv->modulus, NFT_NG_RANDOM,
2b03bf73 LGL	212	priv->offset);
91dbc6be LGL	213	}
	214
	215	static struct nft_expr_type nft_ng_type;
	216	static const struct nft_expr_ops nft_ng_inc_ops = {
	217	.type = &nft_ng_type,
	218	.size = NFT_EXPR_SIZE(sizeof(struct nft_ng_inc)),
	219	.eval = nft_ng_inc_eval,
	220	.init = nft_ng_inc_init,
	221	.dump = nft_ng_inc_dump,
	222	};
	223
d734a288 LGL	224	static const struct nft_expr_ops nft_ng_inc_map_ops = {
	225	.type = &nft_ng_type,
	226	.size = NFT_EXPR_SIZE(sizeof(struct nft_ng_inc)),
	227	.eval = nft_ng_inc_map_eval,
	228	.init = nft_ng_inc_map_init,
	229	.dump = nft_ng_inc_map_dump,
	230	};
	231
91dbc6be LGL	232	static const struct nft_expr_ops nft_ng_random_ops = {
	233	.type = &nft_ng_type,
	234	.size = NFT_EXPR_SIZE(sizeof(struct nft_ng_random)),
	235	.eval = nft_ng_random_eval,
	236	.init = nft_ng_random_init,
	237	.dump = nft_ng_random_dump,
	238	};
	239
	240	static const struct nft_expr_ops *
	241	nft_ng_select_ops(const struct nft_ctx ctx, const struct nlattr const tb[])
	242	{
	243	u32 type;
	244
0d9932b2 LGL	245	if (!tb[NFTA_NG_DREG] \|\|
0d9932b2 LGL	246	!tb[NFTA_NG_MODULUS] \|\|
91dbc6be LGL	247	!tb[NFTA_NG_TYPE])
	248	return ERR_PTR(-EINVAL);
	249
	250	type = ntohl(nla_get_be32(tb[NFTA_NG_TYPE]));
	251
	252	switch (type) {
	253	case NFT_NG_INCREMENTAL:
d734a288 LGL	254	if (tb[NFTA_NG_SET_NAME])
d734a288 LGL	255	return &nft_ng_inc_map_ops;
91dbc6be LGL	256	return &nft_ng_inc_ops;
	257	case NFT_NG_RANDOM:
	258	return &nft_ng_random_ops;
	259	}
	260
	261	return ERR_PTR(-EINVAL);
	262	}
	263
	264	static struct nft_expr_type nft_ng_type __read_mostly = {
	265	.name = "numgen",
d4ef3835	266	.select_ops = nft_ng_select_ops,
91dbc6be LGL	267	.policy = nft_ng_policy,
	268	.maxattr = NFTA_NG_MAX,
	269	.owner = THIS_MODULE,
	270	};
	271
	272	static int __init nft_ng_module_init(void)
	273	{
	274	return nft_register_expr(&nft_ng_type);
	275	}
	276
	277	static void __exit nft_ng_module_exit(void)
	278	{
	279	nft_unregister_expr(&nft_ng_type);
	280	}
	281
	282	module_init(nft_ng_module_init);
	283	module_exit(nft_ng_module_exit);
	284
	285	MODULE_LICENSE("GPL");
	286	MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
	287	MODULE_ALIAS_NFT_EXPR("numgen");