summaryrefslogtreecommitdiffstats
path: root/net/netfilter/nft_dynset.c
blob: e3b83c31da2e56ee9932d4d3d22dc8acfd87a617 (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
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
/*
 * Copyright (c) 2015 Patrick McHardy <kaber@trash.net>
 *
 * 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/module.h>
#include <linux/init.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>

struct nft_dynset {
	struct nft_set			*set;
	struct nft_set_ext_tmpl		tmpl;
	enum nft_dynset_ops		op:8;
	enum nft_registers		sreg_key:8;
	enum nft_registers		sreg_data:8;
	bool				invert;
	u64				timeout;
	struct nft_expr			*expr;
	struct nft_set_binding		binding;
};

static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
			    struct nft_regs *regs)
{
	const struct nft_dynset *priv = nft_expr_priv(expr);
	struct nft_set_ext *ext;
	u64 timeout;
	void *elem;

	if (set->size && !atomic_add_unless(&set->nelems, 1, set->size))
		return NULL;

	timeout = priv->timeout ? : set->timeout;
	elem = nft_set_elem_init(set, &priv->tmpl,
				 &regs->data[priv->sreg_key],
				 &regs->data[priv->sreg_data],
				 timeout, GFP_ATOMIC);
	if (elem == NULL) {
		if (set->size)
			atomic_dec(&set->nelems);
		return NULL;
	}

	ext = nft_set_elem_ext(set, elem);
	if (priv->expr != NULL &&
	    nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0)
		return NULL;

	return elem;
}

static void nft_dynset_eval(const struct nft_expr *expr,
			    struct nft_regs *regs,
			    const struct nft_pktinfo *pkt)
{
	const struct nft_dynset *priv = nft_expr_priv(expr);
	struct nft_set *set = priv->set;
	const struct nft_set_ext *ext;
	const struct nft_expr *sexpr;
	u64 timeout;

	if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
			     expr, regs, &ext)) {
		sexpr = NULL;
		if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
			sexpr = nft_set_ext_expr(ext);

		if (priv->op == NFT_DYNSET_OP_UPDATE &&
		    nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
			timeout = priv->timeout ? : set->timeout;
			*nft_set_ext_expiration(ext) = jiffies + timeout;
		} else if (sexpr == NULL)
			goto out;

		if (sexpr != NULL)
			sexpr->ops->eval(sexpr, regs, pkt);

		if (priv->invert)
			regs->verdict.code = NFT_BREAK;
		return;
	}
out:
	if (!priv->invert)
		regs->verdict.code = NFT_BREAK;
}

static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
	[NFTA_DYNSET_SET_NAME]	= { .type = NLA_STRING },
	[NFTA_DYNSET_SET_ID]	= { .type = NLA_U32 },
	[NFTA_DYNSET_OP]	= { .type = NLA_U32 },
	[NFTA_DYNSET_SREG_KEY]	= { .type = NLA_U32 },
	[NFTA_DYNSET_SREG_DATA]	= { .type = NLA_U32 },
	[NFTA_DYNSET_TIMEOUT]	= { .type = NLA_U64 },
	[NFTA_DYNSET_EXPR]	= { .type = NLA_NESTED },
	[NFTA_DYNSET_FLAGS]	= { .type = NLA_U32 },
};

static int nft_dynset_init(const struct nft_ctx *ctx,
			   const struct nft_expr *expr,
			   const struct nlattr * const tb[])
{
	struct nft_dynset *priv = nft_expr_priv(expr);
	u8 genmask = nft_genmask_next(ctx->net);
	struct nft_set *set;
	u64 timeout;
	int err;

	if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
	    tb[NFTA_DYNSET_OP] == NULL ||
	    tb[NFTA_DYNSET_SREG_KEY] == NULL)
		return -EINVAL;

	if (tb[NFTA_DYNSET_FLAGS]) {
		u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));

		if (flags & ~NFT_DYNSET_F_INV)
			return -EINVAL;
		if (flags & NFT_DYNSET_F_INV)
			priv->invert = true;
	}

	set = nf_tables_set_lookup(ctx->table, tb[NFTA_DYNSET_SET_NAME],
				   genmask);
	if (IS_ERR(set)) {
		if (tb[NFTA_DYNSET_SET_ID])
			set = nf_tables_set_lookup_byid(ctx->net,
							tb[NFTA_DYNSET_SET_ID],
							genmask);
		if (IS_ERR(set))
			return PTR_ERR(set);
	}

	if (set->flags & NFT_SET_CONSTANT)
		return -EBUSY;

	priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
	switch (priv->op) {
	case NFT_DYNSET_OP_ADD:
		break;
	case NFT_DYNSET_OP_UPDATE:
		if (!(set->flags & NFT_SET_TIMEOUT))
			return -EOPNOTSUPP;
		break;
	default:
		return -EOPNOTSUPP;
	}

	timeout = 0;
	if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
		if (!(set->flags & NFT_SET_TIMEOUT))
			return -EINVAL;
		timeout = be64_to_cpu(nla_get_be64(tb[NFTA_DYNSET_TIMEOUT]));
	}

	priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
	err = nft_validate_register_load(priv->sreg_key, set->klen);;
	if (err < 0)
		return err;

	if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
		if (!(set->flags & NFT_SET_MAP))
			return -EINVAL;
		if (set->dtype == NFT_DATA_VERDICT)
			return -EOPNOTSUPP;

		priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
		err = nft_validate_register_load(priv->sreg_data, set->dlen);
		if (err < 0)
			return err;
	} else if (set->flags & NFT_SET_MAP)
		return -EINVAL;

	if (tb[NFTA_DYNSET_EXPR] != NULL) {
		if (!(set->flags & NFT_SET_EVAL))
			return -EINVAL;
		if (!(set->flags & NFT_SET_ANONYMOUS))
			return -EOPNOTSUPP;

		priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]);
		if (IS_ERR(priv->expr))
			return PTR_ERR(priv->expr);

		err = -EOPNOTSUPP;
		if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL))
			goto err1;
	} else if (set->flags & NFT_SET_EVAL)
		return -EINVAL;

	nft_set_ext_prepare(&priv->tmpl);
	nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
	if (set->flags & NFT_SET_MAP)
		nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
	if (priv->expr != NULL)
		nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
				       priv->expr->ops->size);
	if (set->flags & NFT_SET_TIMEOUT) {
		if (timeout || set->timeout)
			nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
	}

	priv->timeout = timeout;

	err = nf_tables_bind_set(ctx, set, &priv->binding);
	if (err < 0)
		goto err1;

	priv->set = set;
	return 0;

err1:
	if (priv->expr != NULL)
		nft_expr_destroy(ctx, priv->expr);
	return err;
}

static void nft_dynset_destroy(const struct nft_ctx *ctx,
			       const struct nft_expr *expr)
{
	struct nft_dynset *priv = nft_expr_priv(expr);

	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
	if (priv->expr != NULL)
		nft_expr_destroy(ctx, priv->expr);
}

static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
	const struct nft_dynset *priv = nft_expr_priv(expr);
	u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;

	if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
		goto nla_put_failure;
	if (priv->set->flags & NFT_SET_MAP &&
	    nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
		goto nla_put_failure;
	if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
		goto nla_put_failure;
	if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, cpu_to_be64(priv->timeout),
			 NFTA_DYNSET_PAD))
		goto nla_put_failure;
	if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -1;
}

static struct nft_expr_type nft_dynset_type;
static const struct nft_expr_ops nft_dynset_ops = {
	.type		= &nft_dynset_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
	.eval		= nft_dynset_eval,
	.init		= nft_dynset_init,
	.destroy	= nft_dynset_destroy,
	.dump		= nft_dynset_dump,
};

static struct nft_expr_type nft_dynset_type __read_mostly = {
	.name		= "dynset",
	.ops		= &nft_dynset_ops,
	.policy		= nft_dynset_policy,
	.maxattr	= NFTA_DYNSET_MAX,
	.owner		= THIS_MODULE,
};

int __init nft_dynset_module_init(void)
{
	return nft_register_expr(&nft_dynset_type);
}

void nft_dynset_module_exit(void)
{
	nft_unregister_expr(&nft_dynset_type);
}