summaryrefslogtreecommitdiff
path: root/net/netfilter/nft_dynset.c
blob: 6ba3256fa844989461b28af793e7465a40353f17 (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
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015 Patrick McHardy <kaber@trash.net>
 */

#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;
	u8				sreg_key;
	u8				sreg_data;
	bool				invert;
	bool				expr;
	u8				num_exprs;
	u64				timeout;
	struct nft_expr			*expr_array[NFT_SET_EXPR_MAX];
	struct nft_set_binding		binding;
};

static int nft_dynset_expr_setup(const struct nft_dynset *priv,
				 const struct nft_set_ext *ext)
{
	struct nft_set_elem_expr *elem_expr = nft_set_ext_expr(ext);
	struct nft_expr *expr;
	int i;

	for (i = 0; i < priv->num_exprs; i++) {
		expr = nft_setelem_expr_at(elem_expr, elem_expr->size);
		if (nft_expr_clone(expr, priv->expr_array[i]) < 0)
			return -1;

		elem_expr->size += priv->expr_array[i]->ops->size;
	}

	return 0;
}

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 (!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], NULL,
				 &regs->data[priv->sreg_data],
				 timeout, 0, GFP_ATOMIC);
	if (elem == NULL)
		goto err1;

	ext = nft_set_elem_ext(set, elem);
	if (priv->num_exprs && nft_dynset_expr_setup(priv, ext) < 0)
		goto err2;

	return elem;

err2:
	nft_set_elem_destroy(set, elem, false);
err1:
	if (set->size)
		atomic_dec(&set->nelems);
	return NULL;
}

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;
	u64 timeout;

	if (priv->op == NFT_DYNSET_OP_DELETE) {
		set->ops->delete(set, &regs->data[priv->sreg_key]);
		return;
	}

	if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
			     expr, regs, &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) = get_jiffies_64() + timeout;
		}

		nft_set_elem_update_expr(ext, regs, pkt);

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

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

static void nft_dynset_ext_add_expr(struct nft_dynset *priv)
{
	u8 size = 0;
	int i;

	for (i = 0; i < priv->num_exprs; i++)
		size += priv->expr_array[i]->ops->size;

	nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPRESSIONS,
			       sizeof(struct nft_set_elem_expr) + size);
}

static struct nft_expr *
nft_dynset_expr_alloc(const struct nft_ctx *ctx, const struct nft_set *set,
		      const struct nlattr *attr, int pos)
{
	struct nft_expr *expr;
	int err;

	expr = nft_set_elem_expr_alloc(ctx, set, attr);
	if (IS_ERR(expr))
		return expr;

	if (set->exprs[pos] && set->exprs[pos]->ops != expr->ops) {
		err = -EOPNOTSUPP;
		goto err_dynset_expr;
	}

	return expr;

err_dynset_expr:
	nft_expr_destroy(ctx, expr);
	return ERR_PTR(err);
}

static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
	[NFTA_DYNSET_SET_NAME]	= { .type = NLA_STRING,
				    .len = NFT_SET_MAXNAMELEN - 1 },
	[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 },
	[NFTA_DYNSET_EXPRESSIONS] = { .type = NLA_NESTED },
};

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

	lockdep_assert_held(&nft_net->commit_mutex);

	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 | NFT_DYNSET_F_EXPR))
			return -EOPNOTSUPP;
		if (flags & NFT_DYNSET_F_INV)
			priv->invert = true;
		if (flags & NFT_DYNSET_F_EXPR)
			priv->expr = true;
	}

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

	if (set->ops->update == NULL)
		return -EOPNOTSUPP;

	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:
	case NFT_DYNSET_OP_DELETE:
		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 -EOPNOTSUPP;

		err = nf_msecs_to_jiffies64(tb[NFTA_DYNSET_TIMEOUT], &timeout);
		if (err)
			return err;
	}

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

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

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

	if ((tb[NFTA_DYNSET_EXPR] || tb[NFTA_DYNSET_EXPRESSIONS]) &&
	    !(set->flags & NFT_SET_EVAL))
		return -EINVAL;

	if (tb[NFTA_DYNSET_EXPR]) {
		struct nft_expr *dynset_expr;

		dynset_expr = nft_dynset_expr_alloc(ctx, set,
						    tb[NFTA_DYNSET_EXPR], 0);
		if (IS_ERR(dynset_expr))
			return PTR_ERR(dynset_expr);

		priv->num_exprs++;
		priv->expr_array[0] = dynset_expr;

		if (set->num_exprs > 1 ||
		    (set->num_exprs == 1 &&
		     dynset_expr->ops != set->exprs[0]->ops)) {
			err = -EOPNOTSUPP;
			goto err_expr_free;
		}
	} else if (tb[NFTA_DYNSET_EXPRESSIONS]) {
		struct nft_expr *dynset_expr;
		struct nlattr *tmp;
		int left;

		if (!priv->expr)
			return -EINVAL;

		i = 0;
		nla_for_each_nested(tmp, tb[NFTA_DYNSET_EXPRESSIONS], left) {
			if (i == NFT_SET_EXPR_MAX) {
				err = -E2BIG;
				goto err_expr_free;
			}
			if (nla_type(tmp) != NFTA_LIST_ELEM) {
				err = -EINVAL;
				goto err_expr_free;
			}
			dynset_expr = nft_dynset_expr_alloc(ctx, set, tmp, i);
			if (IS_ERR(dynset_expr)) {
				err = PTR_ERR(dynset_expr);
				goto err_expr_free;
			}
			priv->expr_array[i] = dynset_expr;
			priv->num_exprs++;

			if (set->num_exprs &&
			    dynset_expr->ops != set->exprs[i]->ops) {
				err = -EOPNOTSUPP;
				goto err_expr_free;
			}
			i++;
		}
		if (set->num_exprs && set->num_exprs != i) {
			err = -EOPNOTSUPP;
			goto err_expr_free;
		}
	} else if (set->num_exprs > 0) {
		err = nft_set_elem_expr_clone(ctx, set, priv->expr_array);
		if (err < 0)
			return err;

		priv->num_exprs = set->num_exprs;
	}

	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->num_exprs)
		nft_dynset_ext_add_expr(priv);

	if (set->flags & NFT_SET_TIMEOUT) {
		if (timeout || set->timeout) {
			nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_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 err_expr_free;

	if (set->size == 0)
		set->size = 0xffff;

	priv->set = set;
	return 0;

err_expr_free:
	for (i = 0; i < priv->num_exprs; i++)
		nft_expr_destroy(ctx, priv->expr_array[i]);
	return err;
}

static void nft_dynset_deactivate(const struct nft_ctx *ctx,
				  const struct nft_expr *expr,
				  enum nft_trans_phase phase)
{
	struct nft_dynset *priv = nft_expr_priv(expr);

	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
}

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

	priv->set->use++;
}

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

	for (i = 0; i < priv->num_exprs; i++)
		nft_expr_destroy(ctx, priv->expr_array[i]);

	nf_tables_destroy_set(ctx, priv->set);
}

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;
	int i;

	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,
			 nf_jiffies64_to_msecs(priv->timeout),
			 NFTA_DYNSET_PAD))
		goto nla_put_failure;
	if (priv->set->num_exprs == 0) {
		if (priv->num_exprs == 1) {
			if (nft_expr_dump(skb, NFTA_DYNSET_EXPR,
					  priv->expr_array[0]))
				goto nla_put_failure;
		} else if (priv->num_exprs > 1) {
			struct nlattr *nest;

			nest = nla_nest_start_noflag(skb, NFTA_DYNSET_EXPRESSIONS);
			if (!nest)
				goto nla_put_failure;

			for (i = 0; i < priv->num_exprs; i++) {
				if (nft_expr_dump(skb, NFTA_LIST_ELEM,
						  priv->expr_array[i]))
					goto nla_put_failure;
			}
			nla_nest_end(skb, nest);
		}
	}
	if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -1;
}

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,
	.activate	= nft_dynset_activate,
	.deactivate	= nft_dynset_deactivate,
	.dump		= nft_dynset_dump,
};

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,
};