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

/*
 * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * 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/atomic.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>

struct nft_quota {
	u64		quota;
	bool		invert;
	atomic64_t	consumed;
};

static inline bool nft_overquota(struct nft_quota *priv,
				 const struct sk_buff *skb)
{
	return atomic64_add_return(skb->len, &priv->consumed) >= priv->quota;
}

static inline void nft_quota_do_eval(struct nft_quota *priv,
				     struct nft_regs *regs,
				     const struct nft_pktinfo *pkt)
{
	if (nft_overquota(priv, pkt->skb) ^ priv->invert)
		regs->verdict.code = NFT_BREAK;
}

static const struct nla_policy nft_quota_policy[NFTA_QUOTA_MAX + 1] = {
	[NFTA_QUOTA_BYTES]	= { .type = NLA_U64 },
	[NFTA_QUOTA_FLAGS]	= { .type = NLA_U32 },
};

static void nft_quota_obj_eval(struct nft_object *obj,
			       struct nft_regs *regs,
			       const struct nft_pktinfo *pkt)
{
	struct nft_quota *priv = nft_obj_data(obj);

	nft_quota_do_eval(priv, regs, pkt);
}

static int nft_quota_do_init(const struct nlattr * const tb[],
			     struct nft_quota *priv)
{
	u32 flags = 0;
	u64 quota;

	if (!tb[NFTA_QUOTA_BYTES])
		return -EINVAL;

	quota = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_BYTES]));
	if (quota > S64_MAX)
		return -EOVERFLOW;

	if (tb[NFTA_QUOTA_FLAGS]) {
		flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS]));
		if (flags & ~NFT_QUOTA_F_INV)
			return -EINVAL;
	}

	priv->quota = quota;
	priv->invert = (flags & NFT_QUOTA_F_INV) ? true : false;
	atomic64_set(&priv->consumed, 0);

	return 0;
}

static int nft_quota_obj_init(const struct nlattr * const tb[],
			      struct nft_object *obj)
{
	struct nft_quota *priv = nft_obj_data(obj);

	return nft_quota_do_init(tb, priv);
}

static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
			     bool reset)
{
	u32 flags = priv->invert ? NFT_QUOTA_F_INV : 0;
	u64 consumed;

	if (reset)
		consumed = atomic64_xchg(&priv->consumed, 0);
	else
		consumed = atomic64_read(&priv->consumed);

	/* Since we inconditionally increment consumed quota for each packet
	 * that we see, don't go over the quota boundary in what we send to
	 * userspace.
	 */
	if (consumed > priv->quota)
		consumed = priv->quota;

	if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(priv->quota),
			 NFTA_QUOTA_PAD) ||
	    nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed),
			 NFTA_QUOTA_PAD) ||
	    nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -1;
}

static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj,
			      bool reset)
{
	struct nft_quota *priv = nft_obj_data(obj);

	return nft_quota_do_dump(skb, priv, reset);
}

static struct nft_object_type nft_quota_obj __read_mostly = {
	.type		= NFT_OBJECT_QUOTA,
	.size		= sizeof(struct nft_quota),
	.maxattr	= NFTA_QUOTA_MAX,
	.policy		= nft_quota_policy,
	.init		= nft_quota_obj_init,
	.eval		= nft_quota_obj_eval,
	.dump		= nft_quota_obj_dump,
	.owner		= THIS_MODULE,
};

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

	nft_quota_do_eval(priv, regs, pkt);
}

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

	return nft_quota_do_init(tb, priv);
}

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

	return nft_quota_do_dump(skb, priv, false);
}

static struct nft_expr_type nft_quota_type;
static const struct nft_expr_ops nft_quota_ops = {
	.type		= &nft_quota_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_quota)),
	.eval		= nft_quota_eval,
	.init		= nft_quota_init,
	.dump		= nft_quota_dump,
};

static struct nft_expr_type nft_quota_type __read_mostly = {
	.name		= "quota",
	.ops		= &nft_quota_ops,
	.policy		= nft_quota_policy,
	.maxattr	= NFTA_QUOTA_MAX,
	.flags		= NFT_EXPR_STATEFUL,
	.owner		= THIS_MODULE,
};

static int __init nft_quota_module_init(void)
{
	int err;

	err = nft_register_obj(&nft_quota_obj);
	if (err < 0)
		return err;

	err = nft_register_expr(&nft_quota_type);
	if (err < 0)
		goto err1;

	return 0;
err1:
	nft_unregister_obj(&nft_quota_obj);
	return err;
}

static void __exit nft_quota_module_exit(void)
{
	nft_unregister_expr(&nft_quota_type);
	nft_unregister_obj(&nft_quota_obj);
}

module_init(nft_quota_module_init);
module_exit(nft_quota_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_EXPR("quota");
MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA);
Commit	Line	Data
3d2f30a1 PNA	1	/*
	2	* Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
	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	#include <linux/kernel.h>
	10	#include <linux/init.h>
	11	#include <linux/module.h>
	12	#include <linux/atomic.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
	18	struct nft_quota {
	19	u64 quota;
	20	bool invert;
795595f6	21	atomic64_t consumed;
3d2f30a1 PNA	22	};
3d2f30a1 PNA	23
22609b43	24	static inline bool nft_overquota(struct nft_quota *priv,
795595f6	25	const struct sk_buff *skb)
3d2f30a1	26	{
795595f6	27	return atomic64_add_return(skb->len, &priv->consumed) >= priv->quota;
3d2f30a1 PNA	28	}
3d2f30a1 PNA	29
173705d9 PNA	30	static inline void nft_quota_do_eval(struct nft_quota *priv,
	31	struct nft_regs *regs,
	32	const struct nft_pktinfo *pkt)
3d2f30a1	33	{
795595f6	34	if (nft_overquota(priv, pkt->skb) ^ priv->invert)
3d2f30a1 PNA	35	regs->verdict.code = NFT_BREAK;
	36	}
	37
	38	static const struct nla_policy nft_quota_policy[NFTA_QUOTA_MAX + 1] = {
	39	[NFTA_QUOTA_BYTES] = { .type = NLA_U64 },
	40	[NFTA_QUOTA_FLAGS] = { .type = NLA_U32 },
	41	};
	42
173705d9 PNA	43	static void nft_quota_obj_eval(struct nft_object *obj,
	44	struct nft_regs *regs,
	45	const struct nft_pktinfo *pkt)
	46	{
	47	struct nft_quota *priv = nft_obj_data(obj);
	48
	49	nft_quota_do_eval(priv, regs, pkt);
	50	}
	51
	52	static int nft_quota_do_init(const struct nlattr * const tb[],
	53	struct nft_quota *priv)
3d2f30a1	54	{
3d2f30a1 PNA	55	u32 flags = 0;
	56	u64 quota;
	57
	58	if (!tb[NFTA_QUOTA_BYTES])
	59	return -EINVAL;
	60
	61	quota = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_BYTES]));
	62	if (quota > S64_MAX)
	63	return -EOVERFLOW;
	64
	65	if (tb[NFTA_QUOTA_FLAGS]) {
	66	flags = ntohl(nla_get_be32(tb[NFTA_QUOTA_FLAGS]));
	67	if (flags & ~NFT_QUOTA_F_INV)
	68	return -EINVAL;
	69	}
	70
	71	priv->quota = quota;
	72	priv->invert = (flags & NFT_QUOTA_F_INV) ? true : false;
795595f6	73	atomic64_set(&priv->consumed, 0);
3d2f30a1 PNA	74
	75	return 0;
	76	}
	77
173705d9 PNA	78	static int nft_quota_obj_init(const struct nlattr * const tb[],
	79	struct nft_object *obj)
	80	{
	81	struct nft_quota *priv = nft_obj_data(obj);
	82
	83	return nft_quota_do_init(tb, priv);
	84	}
	85
43da04a5 PNA	86	static int nft_quota_do_dump(struct sk_buff skb, struct nft_quota priv,
43da04a5 PNA	87	bool reset)
3d2f30a1	88	{
3d2f30a1	89	u32 flags = priv->invert ? NFT_QUOTA_F_INV : 0;
795595f6 PNA	90	u64 consumed;
795595f6 PNA	91
43da04a5 PNA	92	if (reset)
	93	consumed = atomic64_xchg(&priv->consumed, 0);
	94	else
	95	consumed = atomic64_read(&priv->consumed);
	96
795595f6 PNA	97	/* Since we inconditionally increment consumed quota for each packet
	98	* that we see, don't go over the quota boundary in what we send to
	99	* userspace.
	100	*/
	101	if (consumed > priv->quota)
	102	consumed = priv->quota;
3d2f30a1 PNA	103
	104	if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(priv->quota),
	105	NFTA_QUOTA_PAD) \|\|
795595f6 PNA	106	nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed),
795595f6 PNA	107	NFTA_QUOTA_PAD) \|\|
3d2f30a1 PNA	108	nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
	109	goto nla_put_failure;
	110	return 0;
	111
	112	nla_put_failure:
	113	return -1;
	114	}
	115
43da04a5 PNA	116	static int nft_quota_obj_dump(struct sk_buff skb, struct nft_object obj,
43da04a5 PNA	117	bool reset)
173705d9 PNA	118	{
	119	struct nft_quota *priv = nft_obj_data(obj);
	120
43da04a5	121	return nft_quota_do_dump(skb, priv, reset);
173705d9 PNA	122	}
	123
	124	static struct nft_object_type nft_quota_obj __read_mostly = {
	125	.type = NFT_OBJECT_QUOTA,
	126	.size = sizeof(struct nft_quota),
	127	.maxattr = NFTA_QUOTA_MAX,
	128	.policy = nft_quota_policy,
	129	.init = nft_quota_obj_init,
	130	.eval = nft_quota_obj_eval,
	131	.dump = nft_quota_obj_dump,
	132	.owner = THIS_MODULE,
	133	};
	134
	135	static void nft_quota_eval(const struct nft_expr *expr,
	136	struct nft_regs *regs,
	137	const struct nft_pktinfo *pkt)
	138	{
	139	struct nft_quota *priv = nft_expr_priv(expr);
	140
	141	nft_quota_do_eval(priv, regs, pkt);
	142	}
	143
	144	static int nft_quota_init(const struct nft_ctx *ctx,
	145	const struct nft_expr *expr,
	146	const struct nlattr * const tb[])
	147	{
	148	struct nft_quota *priv = nft_expr_priv(expr);
	149
	150	return nft_quota_do_init(tb, priv);
	151	}
	152
	153	static int nft_quota_dump(struct sk_buff skb, const struct nft_expr expr)
	154	{
43da04a5	155	struct nft_quota *priv = nft_expr_priv(expr);
173705d9	156
43da04a5	157	return nft_quota_do_dump(skb, priv, false);
173705d9 PNA	158	}
173705d9 PNA	159
3d2f30a1 PNA	160	static struct nft_expr_type nft_quota_type;
	161	static const struct nft_expr_ops nft_quota_ops = {
	162	.type = &nft_quota_type,
	163	.size = NFT_EXPR_SIZE(sizeof(struct nft_quota)),
	164	.eval = nft_quota_eval,
	165	.init = nft_quota_init,
	166	.dump = nft_quota_dump,
	167	};
	168
	169	static struct nft_expr_type nft_quota_type __read_mostly = {
	170	.name = "quota",
	171	.ops = &nft_quota_ops,
	172	.policy = nft_quota_policy,
	173	.maxattr = NFTA_QUOTA_MAX,
	174	.flags = NFT_EXPR_STATEFUL,
	175	.owner = THIS_MODULE,
	176	};
	177
	178	static int __init nft_quota_module_init(void)
	179	{
173705d9 PNA	180	int err;
	181
	182	err = nft_register_obj(&nft_quota_obj);
	183	if (err < 0)
	184	return err;
	185
	186	err = nft_register_expr(&nft_quota_type);
	187	if (err < 0)
	188	goto err1;
	189
	190	return 0;
	191	err1:
	192	nft_unregister_obj(&nft_quota_obj);
	193	return err;
3d2f30a1 PNA	194	}
	195
	196	static void __exit nft_quota_module_exit(void)
	197	{
173705d9 PNA	198	nft_unregister_expr(&nft_quota_type);
173705d9 PNA	199	nft_unregister_obj(&nft_quota_obj);
3d2f30a1 PNA	200	}
	201
	202	module_init(nft_quota_module_init);
	203	module_exit(nft_quota_module_exit);
	204
	205	MODULE_LICENSE("GPL");
	206	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	207	MODULE_ALIAS_NFT_EXPR("quota");
173705d9	208	MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_QUOTA);