summaryrefslogtreecommitdiffstats
path: root/src/expr/cmp.c
blob: b5c694a4dea32eea651dab8dce6d217baaed3914 (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
/*
 * (C) 2012 by 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 as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
 */

#include "internal.h"

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <arpa/inet.h>
#include <errno.h>

#include <libmnl/libmnl.h>
#include <linux/netfilter/nf_tables.h>
#include <libnftables/expr.h>
#include <libnftables/rule.h>
#include "expr_ops.h"
#include "data_reg.h"

struct nft_expr_cmp {
	union nft_data_reg	data;
	enum nft_registers	sreg;
	enum nft_cmp_ops	op;
};

static int
nft_rule_expr_cmp_set(struct nft_rule_expr *e, uint16_t type,
		      const void *data, uint32_t data_len)
{
	struct nft_expr_cmp *cmp = nft_expr_data(e);

	switch(type) {
	case NFT_EXPR_CMP_SREG:
		cmp->sreg = *((uint32_t *)data);
		break;
	case NFT_EXPR_CMP_OP:
		cmp->op = *((uint32_t *)data);
		break;
	case NFT_EXPR_CMP_DATA:
		memcpy(&cmp->data.val, data, data_len);
		cmp->data.len = data_len;
		break;
	default:
		return -1;
	}
	return 0;
}

static const void *
nft_rule_expr_cmp_get(const struct nft_rule_expr *e, uint16_t type,
		      uint32_t *data_len)
{
	struct nft_expr_cmp *cmp = nft_expr_data(e);

	switch(type) {
	case NFT_EXPR_CMP_SREG:
		*data_len = sizeof(cmp->sreg);
		return &cmp->sreg;
	case NFT_EXPR_CMP_OP:
		*data_len = sizeof(cmp->op);
		return &cmp->op;
	case NFT_EXPR_CMP_DATA:
		*data_len = cmp->data.len;
		return &cmp->data.val;
	}
	return NULL;
}

static int nft_rule_expr_cmp_cb(const struct nlattr *attr, void *data)
{
	const struct nlattr **tb = data;
	int type = mnl_attr_get_type(attr);

	if (mnl_attr_type_valid(attr, NFTA_CMP_MAX) < 0)
		return MNL_CB_OK;

	switch(type) {
	case NFTA_CMP_SREG:
	case NFTA_CMP_OP:
		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	case NFTA_CMP_DATA:
		if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	}

	tb[type] = attr;
	return MNL_CB_OK;
}

static void
nft_rule_expr_cmp_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
{
	struct nft_expr_cmp *cmp = nft_expr_data(e);

	if (e->flags & (1 << NFT_EXPR_CMP_SREG))
		mnl_attr_put_u32(nlh, NFTA_CMP_SREG, htonl(cmp->sreg));
	if (e->flags & (1 << NFT_EXPR_CMP_OP))
		mnl_attr_put_u32(nlh, NFTA_CMP_OP, htonl(cmp->op));
	if (e->flags & (1 << NFT_EXPR_CMP_DATA)) {
		struct nlattr *nest;

		nest = mnl_attr_nest_start(nlh, NFTA_CMP_DATA);
		mnl_attr_put(nlh, NFTA_DATA_VALUE, cmp->data.len, cmp->data.val);
		mnl_attr_nest_end(nlh, nest);
	}
}

static int
nft_rule_expr_cmp_parse(struct nft_rule_expr *e, struct nlattr *attr)
{
	struct nft_expr_cmp *cmp = nft_expr_data(e);
	struct nlattr *tb[NFTA_CMP_MAX+1] = {};
	int ret = 0;

	if (mnl_attr_parse_nested(attr, nft_rule_expr_cmp_cb, tb) < 0)
		return -1;

	if (tb[NFTA_CMP_SREG]) {
		cmp->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_CMP_SREG]));
		e->flags |= (1 << NFTA_CMP_SREG);
	}
	if (tb[NFTA_CMP_OP]) {
		cmp->op = ntohl(mnl_attr_get_u32(tb[NFTA_CMP_OP]));
		e->flags |= (1 << NFTA_CMP_OP);
	}
	if (tb[NFTA_CMP_DATA]) {
		ret = nft_parse_data(&cmp->data, tb[NFTA_CMP_DATA], NULL);
		e->flags |= (1 << NFTA_CMP_DATA);
	}

	return ret;
}

static char *expr_cmp_str[] = {
	[NFT_CMP_EQ]	= "eq",
	[NFT_CMP_NEQ]	= "neq",
	[NFT_CMP_LT]	= "lt",
	[NFT_CMP_LTE]	= "lte",
	[NFT_CMP_GT]	= "gt",
	[NFT_CMP_GTE]	= "gte",
};

static inline int nft_str2cmp(const char *op)
{
	if (strcmp(op, "eq") == 0)
		return NFT_CMP_EQ;
	else if (strcmp(op, "neq") == 0)
		return NFT_CMP_NEQ;
	else if (strcmp(op, "lt") == 0)
		return NFT_CMP_LT;
	else if (strcmp(op, "lte") == 0)
		return NFT_CMP_LTE;
	else if (strcmp(op, "gt") == 0)
		return NFT_CMP_GT;
	else if (strcmp(op, "gte") == 0)
		return NFT_CMP_GTE;
	else {
		errno = EINVAL;
		return -1;
	}
}

static int nft_rule_expr_cmp_json_parse(struct nft_rule_expr *e, json_t *root,
					struct nft_parse_err *err)
{
#ifdef JSON_PARSING
	struct nft_expr_cmp *cmp = nft_expr_data(e);
	const char *op;
	uint32_t uval32;
	int base;

	if (nft_jansson_parse_val(root, "sreg", NFT_TYPE_U32, &uval32, err) < 0)
		return -1;

	nft_rule_expr_set_u32(e, NFT_EXPR_CMP_SREG, uval32);

	op = nft_jansson_parse_str(root, "op", err);
	if (op == NULL)
		return -1;

	base = nft_str2cmp(op);
	if (base < 0)
		return -1;

	nft_rule_expr_set_u32(e, NFT_EXPR_CMP_OP, base);

	if (nft_jansson_data_reg_parse(root, "cmpdata",
				       &cmp->data, err) != DATA_VALUE)
		return -1;

	e->flags |= (1 << NFT_EXPR_CMP_DATA);

	return 0;
#else
	errno = EOPNOTSUPP;
	return -1;
#endif
}

static int nft_rule_expr_cmp_xml_parse(struct nft_rule_expr *e, mxml_node_t *tree,
				       struct nft_parse_err *err)
{
#ifdef XML_PARSING
	struct nft_expr_cmp *cmp = nft_expr_data(e);
	const char *op;
	int32_t reg, op_value;

	reg = nft_mxml_reg_parse(tree, "sreg", MXML_DESCEND_FIRST, err);
	if (reg < 0)
		return -1;

	cmp->sreg = reg;
	e->flags |= (1 << NFT_EXPR_CMP_SREG);

	op = nft_mxml_str_parse(tree, "op", MXML_DESCEND_FIRST, NFT_XML_MAND,
				err);
	if (op == NULL)
		return -1;

	op_value = nft_str2cmp(op);
	if (op_value < 0)
		return -1;

	cmp->op = op_value;
	e->flags |= (1 << NFT_EXPR_CMP_OP);

	if (nft_mxml_data_reg_parse(tree, "cmpdata",
				    &cmp->data, NFT_XML_MAND,
				    err) != DATA_VALUE)
		return -1;

	e->flags |= (1 << NFT_EXPR_CMP_DATA);

	return 0;
#else
	errno = EOPNOTSUPP;
	return -1;
#endif
}

static int
nft_rule_expr_cmp_snprintf_json(char *buf, size_t size, struct nft_expr_cmp *cmp)
{
	int len = size, offset = 0, ret;

	ret = snprintf(buf, len, "\"sreg\":%u,\"op\":\"%s\",\"cmpdata\":{",
		       cmp->sreg, expr_cmp_str[cmp->op]);
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	ret = nft_data_reg_snprintf(buf+offset, len, &cmp->data,
				    NFT_OUTPUT_JSON, 0, DATA_VALUE);
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	ret = snprintf(buf+offset, len, "}");
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	return offset;
}

static int
nft_rule_expr_cmp_snprintf_xml(char *buf, size_t size, struct nft_expr_cmp *cmp)
{
	int len = size, offset = 0, ret;

	ret = snprintf(buf, len, "<sreg>%u</sreg><op>%s</op><cmpdata>",
		       cmp->sreg, expr_cmp_str[cmp->op]);
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	ret = nft_data_reg_snprintf(buf+offset, len, &cmp->data,
				    NFT_OUTPUT_XML, 0, DATA_VALUE);
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	ret = snprintf(buf+offset, len, "</cmpdata>");
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	return offset;
}

static int
nft_rule_expr_cmp_snprintf_default(char *buf, size_t size,
				   struct nft_expr_cmp *cmp)
{
	int len = size, offset = 0, ret;

	ret = snprintf(buf, len, "%s reg %u ",
		       expr_cmp_str[cmp->op], cmp->sreg);
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	ret = nft_data_reg_snprintf(buf+offset, len, &cmp->data,
				    NFT_OUTPUT_DEFAULT, 0, DATA_VALUE);
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	return offset;
}

static int
nft_rule_expr_cmp_snprintf(char *buf, size_t size, uint32_t type,
			   uint32_t flags, struct nft_rule_expr *e)
{
	struct nft_expr_cmp *cmp = nft_expr_data(e);

	switch(type) {
	case NFT_OUTPUT_DEFAULT:
		return nft_rule_expr_cmp_snprintf_default(buf, size, cmp);
	case NFT_OUTPUT_XML:
		return nft_rule_expr_cmp_snprintf_xml(buf, size, cmp);
	case NFT_OUTPUT_JSON:
		return nft_rule_expr_cmp_snprintf_json(buf, size, cmp);
	default:
		break;
	}
	return -1;
}

struct expr_ops expr_ops_cmp = {
	.name		= "cmp",
	.alloc_len	= sizeof(struct nft_expr_cmp),
	.max_attr	= NFTA_CMP_MAX,
	.set		= nft_rule_expr_cmp_set,
	.get		= nft_rule_expr_cmp_get,
	.parse		= nft_rule_expr_cmp_parse,
	.build		= nft_rule_expr_cmp_build,
	.snprintf	= nft_rule_expr_cmp_snprintf,
	.xml_parse	= nft_rule_expr_cmp_xml_parse,
	.json_parse	= nft_rule_expr_cmp_json_parse,
};
static void __init expr_cmp_init(void)
{
	nft_expr_ops_register(&expr_ops_cmp);
}