summaryrefslogtreecommitdiff
path: root/net/netfilter/nft_quota.c
blob: 4413690591f27303bfa1dade52ece6eeeb60444a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
 */

#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 {
	atomic64_t	quota;
	unsigned long	flags;
	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) >=
	       atomic64_read(&priv->quota);
}

static inline bool nft_quota_invert(struct nft_quota *priv)
{
	return priv->flags & NFT_QUOTA_F_INV;
}

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) ^ nft_quota_invert(priv))
		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 },
	[NFTA_QUOTA_CONSUMED]	= { .type = NLA_U64 },
};

#define NFT_QUOTA_DEPLETED_BIT	1	/* From NFT_QUOTA_F_DEPLETED. */

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);
	bool overquota;

	overquota = nft_overquota(priv, pkt->skb);
	if (overquota ^ nft_quota_invert(priv))
		regs->verdict.code = NFT_BREAK;

	if (overquota &&
	    !test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags))
		nft_obj_notify(nft_net(pkt), obj->key.table, obj, 0, 0,
			       NFT_MSG_NEWOBJ, nft_pf(pkt), 0, GFP_ATOMIC);
}

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

	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_CONSUMED]) {
		consumed = be64_to_cpu(nla_get_be64(tb[NFTA_QUOTA_CONSUMED]));
		if (consumed > quota)
			return -EINVAL;
	}

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

	atomic64_set(&priv->quota, quota);
	priv->flags = flags;
	atomic64_set(&priv->consumed, consumed);

	return 0;
}

static int nft_quota_obj_init(const struct nft_ctx *ctx,
			      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 void nft_quota_obj_update(struct nft_object *obj,
				 struct nft_object *newobj)
{
	struct nft_quota *newpriv = nft_obj_data(newobj);
	struct nft_quota *priv = nft_obj_data(obj);
	u64 newquota;

	newquota = atomic64_read(&newpriv->quota);
	atomic64_set(&priv->quota, newquota);
	priv->flags = newpriv->flags;
}

static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
			     bool reset)
{
	u64 consumed, consumed_cap, quota;
	u32 flags = priv->flags;

	/* 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.
	 */
	consumed = atomic64_read(&priv->consumed);
	quota = atomic64_read(&priv->quota);
	if (consumed >= quota) {
		consumed_cap = quota;
		flags |= NFT_QUOTA_F_DEPLETED;
	} else {
		consumed_cap = consumed;
	}

	if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(quota),
			 NFTA_QUOTA_PAD) ||
	    nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap),
			 NFTA_QUOTA_PAD) ||
	    nla_put_be32(skb, NFTA_QUOTA_FLAGS, htonl(flags)))
		goto nla_put_failure;

	if (reset) {
		atomic64_sub(consumed, &priv->consumed);
		clear_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags);
	}
	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_type;
static const struct nft_object_ops nft_quota_obj_ops = {
	.type		= &nft_quota_obj_type,
	.size		= sizeof(struct nft_quota),
	.init		= nft_quota_obj_init,
	.eval		= nft_quota_obj_eval,
	.dump		= nft_quota_obj_dump,
	.update		= nft_quota_obj_update,
};

static struct nft_object_type nft_quota_obj_type __read_mostly = {
	.type		= NFT_OBJECT_QUOTA,
	.ops		= &nft_quota_obj_ops,
	.maxattr	= NFTA_QUOTA_MAX,
	.policy		= nft_quota_policy,
	.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_type);
	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_type);
	return err;
}

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

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);