[mirror_ubuntu-jammy-kernel.git] / net / netfilter / nft_numgen.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
 */

#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 {
	u8			dreg;
	u32			modulus;
	atomic_t		counter;
	u32			offset;
};

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 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 },
};

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;

	atomic_set(&priv->counter, priv->modulus - 1);

	return nft_parse_register_store(ctx, tb[NFTA_NG_DREG], &priv->dreg,
					NULL, NFT_DATA_VALUE, sizeof(u32));
}

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);
}

struct nft_ng_random {
	u8			dreg;
	u32			modulus;
	u32			offset;
};

static u32 nft_ng_random_gen(struct nft_ng_random *priv)
{
	struct rnd_state *state = this_cpu_ptr(&nft_numgen_prandom_state);

	return reciprocal_scale(prandom_u32_state(state), priv->modulus) +
	       priv->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);

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

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);

	return nft_parse_register_store(ctx, tb[NFTA_NG_DREG], &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_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:
		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");
MODULE_DESCRIPTION("nftables number generator module");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
91dbc6be LGL	2	/*
91dbc6be LGL	3	* Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
91dbc6be LGL	4	*/
	5
	6	#include <linux/kernel.h>
	7	#include <linux/init.h>
	8	#include <linux/module.h>
	9	#include <linux/netlink.h>
	10	#include <linux/netfilter.h>
	11	#include <linux/netfilter/nf_tables.h>
	12	#include <linux/static_key.h>
	13	#include <net/netfilter/nf_tables.h>
	14	#include <net/netfilter/nf_tables_core.h>
	15
	16	static DEFINE_PER_CPU(struct rnd_state, nft_numgen_prandom_state);
	17
	18	struct nft_ng_inc {
345023b0	19	u8 dreg;
0d9932b2	20	u32 modulus;
91dbc6be	21	atomic_t counter;
2b03bf73	22	u32 offset;
91dbc6be LGL	23	};
91dbc6be LGL	24
d734a288	25	static u32 nft_ng_inc_gen(struct nft_ng_inc *priv)
91dbc6be	26	{
91dbc6be LGL	27	u32 nval, oval;
	28
	29	do {
	30	oval = atomic_read(&priv->counter);
0d9932b2	31	nval = (oval + 1 < priv->modulus) ? oval + 1 : 0;
91dbc6be LGL	32	} while (atomic_cmpxchg(&priv->counter, oval, nval) != oval);
91dbc6be LGL	33
d734a288 LGL	34	return nval + priv->offset;
	35	}
	36
	37	static void nft_ng_inc_eval(const struct nft_expr *expr,
	38	struct nft_regs *regs,
	39	const struct nft_pktinfo *pkt)
	40	{
	41	struct nft_ng_inc *priv = nft_expr_priv(expr);
	42
	43	regs->data[priv->dreg] = nft_ng_inc_gen(priv);
	44	}
	45
91dbc6be LGL	46	static const struct nla_policy nft_ng_policy[NFTA_NG_MAX + 1] = {
91dbc6be LGL	47	[NFTA_NG_DREG] = { .type = NLA_U32 },
0d9932b2	48	[NFTA_NG_MODULUS] = { .type = NLA_U32 },
91dbc6be	49	[NFTA_NG_TYPE] = { .type = NLA_U32 },
2b03bf73	50	[NFTA_NG_OFFSET] = { .type = NLA_U32 },
91dbc6be LGL	51	};
	52
	53	static int nft_ng_inc_init(const struct nft_ctx *ctx,
	54	const struct nft_expr *expr,
	55	const struct nlattr * const tb[])
	56	{
	57	struct nft_ng_inc *priv = nft_expr_priv(expr);
	58
2b03bf73 LGL	59	if (tb[NFTA_NG_OFFSET])
	60	priv->offset = ntohl(nla_get_be32(tb[NFTA_NG_OFFSET]));
	61
0d9932b2 LGL	62	priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
0d9932b2 LGL	63	if (priv->modulus == 0)
91dbc6be LGL	64	return -ERANGE;
91dbc6be LGL	65
2b03bf73 LGL	66	if (priv->offset + priv->modulus - 1 < priv->offset)
	67	return -EOVERFLOW;
	68
0ecba4d9	69	atomic_set(&priv->counter, priv->modulus - 1);
91dbc6be	70
345023b0 PNA	71	return nft_parse_register_store(ctx, tb[NFTA_NG_DREG], &priv->dreg,
345023b0 PNA	72	NULL, NFT_DATA_VALUE, sizeof(u32));
91dbc6be LGL	73	}
	74
	75	static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,
2b03bf73	76	u32 modulus, enum nft_ng_types type, u32 offset)
91dbc6be LGL	77	{
	78	if (nft_dump_register(skb, NFTA_NG_DREG, dreg))
	79	goto nla_put_failure;
0d9932b2	80	if (nla_put_be32(skb, NFTA_NG_MODULUS, htonl(modulus)))
91dbc6be	81	goto nla_put_failure;
7073b16f	82	if (nla_put_be32(skb, NFTA_NG_TYPE, htonl(type)))
91dbc6be	83	goto nla_put_failure;
2b03bf73 LGL	84	if (nla_put_be32(skb, NFTA_NG_OFFSET, htonl(offset)))
2b03bf73 LGL	85	goto nla_put_failure;
91dbc6be LGL	86
	87	return 0;
	88
	89	nla_put_failure:
	90	return -1;
	91	}
	92
	93	static int nft_ng_inc_dump(struct sk_buff skb, const struct nft_expr expr)
	94	{
	95	const struct nft_ng_inc *priv = nft_expr_priv(expr);
	96
2b03bf73 LGL	97	return nft_ng_dump(skb, priv->dreg, priv->modulus, NFT_NG_INCREMENTAL,
2b03bf73 LGL	98	priv->offset);
91dbc6be LGL	99	}
	100
	101	struct nft_ng_random {
345023b0	102	u8 dreg;
0d9932b2	103	u32 modulus;
2b03bf73	104	u32 offset;
91dbc6be LGL	105	};
91dbc6be LGL	106
978d8f90 LGL	107	static u32 nft_ng_random_gen(struct nft_ng_random *priv)
	108	{
	109	struct rnd_state *state = this_cpu_ptr(&nft_numgen_prandom_state);
	110
	111	return reciprocal_scale(prandom_u32_state(state), priv->modulus) +
	112	priv->offset;
	113	}
	114
91dbc6be LGL	115	static void nft_ng_random_eval(const struct nft_expr *expr,
	116	struct nft_regs *regs,
	117	const struct nft_pktinfo *pkt)
	118	{
	119	struct nft_ng_random *priv = nft_expr_priv(expr);
91dbc6be	120
978d8f90 LGL	121	regs->data[priv->dreg] = nft_ng_random_gen(priv);
	122	}
	123
91dbc6be LGL	124	static int nft_ng_random_init(const struct nft_ctx *ctx,
	125	const struct nft_expr *expr,
	126	const struct nlattr * const tb[])
	127	{
	128	struct nft_ng_random *priv = nft_expr_priv(expr);
	129
2b03bf73 LGL	130	if (tb[NFTA_NG_OFFSET])
	131	priv->offset = ntohl(nla_get_be32(tb[NFTA_NG_OFFSET]));
	132
0d9932b2 LGL	133	priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
0d9932b2 LGL	134	if (priv->modulus == 0)
91dbc6be LGL	135	return -ERANGE;
91dbc6be LGL	136
2b03bf73 LGL	137	if (priv->offset + priv->modulus - 1 < priv->offset)
	138	return -EOVERFLOW;
	139
91dbc6be LGL	140	prandom_init_once(&nft_numgen_prandom_state);
91dbc6be LGL	141
345023b0 PNA	142	return nft_parse_register_store(ctx, tb[NFTA_NG_DREG], &priv->dreg,
345023b0 PNA	143	NULL, NFT_DATA_VALUE, sizeof(u32));
91dbc6be LGL	144	}
	145
	146	static int nft_ng_random_dump(struct sk_buff skb, const struct nft_expr expr)
	147	{
	148	const struct nft_ng_random *priv = nft_expr_priv(expr);
	149
2b03bf73 LGL	150	return nft_ng_dump(skb, priv->dreg, priv->modulus, NFT_NG_RANDOM,
2b03bf73 LGL	151	priv->offset);
91dbc6be LGL	152	}
	153
	154	static struct nft_expr_type nft_ng_type;
	155	static const struct nft_expr_ops nft_ng_inc_ops = {
	156	.type = &nft_ng_type,
	157	.size = NFT_EXPR_SIZE(sizeof(struct nft_ng_inc)),
	158	.eval = nft_ng_inc_eval,
	159	.init = nft_ng_inc_init,
	160	.dump = nft_ng_inc_dump,
	161	};
	162
	163	static const struct nft_expr_ops nft_ng_random_ops = {
	164	.type = &nft_ng_type,
	165	.size = NFT_EXPR_SIZE(sizeof(struct nft_ng_random)),
	166	.eval = nft_ng_random_eval,
	167	.init = nft_ng_random_init,
	168	.dump = nft_ng_random_dump,
	169	};
	170
	171	static const struct nft_expr_ops *
	172	nft_ng_select_ops(const struct nft_ctx ctx, const struct nlattr const tb[])
	173	{
	174	u32 type;
	175
0d9932b2 LGL	176	if (!tb[NFTA_NG_DREG] \|\|
0d9932b2 LGL	177	!tb[NFTA_NG_MODULUS] \|\|
91dbc6be LGL	178	!tb[NFTA_NG_TYPE])
	179	return ERR_PTR(-EINVAL);
	180
	181	type = ntohl(nla_get_be32(tb[NFTA_NG_TYPE]));
	182
	183	switch (type) {
	184	case NFT_NG_INCREMENTAL:
	185	return &nft_ng_inc_ops;
	186	case NFT_NG_RANDOM:
	187	return &nft_ng_random_ops;
	188	}
	189
	190	return ERR_PTR(-EINVAL);
	191	}
	192
	193	static struct nft_expr_type nft_ng_type __read_mostly = {
	194	.name = "numgen",
d4ef3835	195	.select_ops = nft_ng_select_ops,
91dbc6be LGL	196	.policy = nft_ng_policy,
	197	.maxattr = NFTA_NG_MAX,
	198	.owner = THIS_MODULE,
	199	};
	200
	201	static int __init nft_ng_module_init(void)
	202	{
	203	return nft_register_expr(&nft_ng_type);
	204	}
	205
	206	static void __exit nft_ng_module_exit(void)
	207	{
	208	nft_unregister_expr(&nft_ng_type);
	209	}
	210
	211	module_init(nft_ng_module_init);
	212	module_exit(nft_ng_module_exit);
	213
	214	MODULE_LICENSE("GPL");
	215	MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
	216	MODULE_ALIAS_NFT_EXPR("numgen");
4cacc395	217	MODULE_DESCRIPTION("nftables number generator module");