summaryrefslogtreecommitdiffstats
path: root/src/expr/bitwise.c
blob: 9ea2f662b3e682c88c1038fca27e7e9ac58d7049 (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
/*
 * (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> /* for memcpy */
#include <arpa/inet.h>
#include <errno.h>
#include <libmnl/libmnl.h>
#include <linux/netfilter/nf_tables.h>
#include <libnftnl/expr.h>
#include <libnftnl/rule.h>

struct nftnl_expr_bitwise {
	enum nft_registers	sreg;
	enum nft_registers	dreg;
	enum nft_bitwise_ops	op;
	unsigned int		len;
	union nftnl_data_reg	mask;
	union nftnl_data_reg	xor;
	union nftnl_data_reg	data;
};

static int
nftnl_expr_bitwise_set(struct nftnl_expr *e, uint16_t type,
		       const void *data, uint32_t data_len)
{
	struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);

	switch(type) {
	case NFTNL_EXPR_BITWISE_SREG:
		memcpy(&bitwise->sreg, data, sizeof(bitwise->sreg));
		break;
	case NFTNL_EXPR_BITWISE_DREG:
		memcpy(&bitwise->dreg, data, sizeof(bitwise->dreg));
		break;
	case NFTNL_EXPR_BITWISE_OP:
		memcpy(&bitwise->op, data, sizeof(bitwise->op));
		break;
	case NFTNL_EXPR_BITWISE_LEN:
		memcpy(&bitwise->len, data, sizeof(bitwise->len));
		break;
	case NFTNL_EXPR_BITWISE_MASK:
		memcpy(&bitwise->mask.val, data, data_len);
		bitwise->mask.len = data_len;
		break;
	case NFTNL_EXPR_BITWISE_XOR:
		memcpy(&bitwise->xor.val, data, data_len);
		bitwise->xor.len = data_len;
		break;
	case NFTNL_EXPR_BITWISE_DATA:
		memcpy(&bitwise->data.val, data, data_len);
		bitwise->data.len = data_len;
		break;
	default:
		return -1;
	}
	return 0;
}

static const void *
nftnl_expr_bitwise_get(const struct nftnl_expr *e, uint16_t type,
		       uint32_t *data_len)
{
	struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);

	switch(type) {
	case NFTNL_EXPR_BITWISE_SREG:
		*data_len = sizeof(bitwise->sreg);
		return &bitwise->sreg;
	case NFTNL_EXPR_BITWISE_DREG:
		*data_len = sizeof(bitwise->dreg);
		return &bitwise->dreg;
	case NFTNL_EXPR_BITWISE_OP:
		*data_len = sizeof(bitwise->op);
		return &bitwise->op;
	case NFTNL_EXPR_BITWISE_LEN:
		*data_len = sizeof(bitwise->len);
		return &bitwise->len;
	case NFTNL_EXPR_BITWISE_MASK:
		*data_len = bitwise->mask.len;
		return &bitwise->mask.val;
	case NFTNL_EXPR_BITWISE_XOR:
		*data_len = bitwise->xor.len;
		return &bitwise->xor.val;
	case NFTNL_EXPR_BITWISE_DATA:
		*data_len = bitwise->data.len;
		return &bitwise->data.val;
	}
	return NULL;
}

static int nftnl_expr_bitwise_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_BITWISE_MAX) < 0)
		return MNL_CB_OK;

	switch(type) {
	case NFTA_BITWISE_SREG:
	case NFTA_BITWISE_DREG:
	case NFTA_BITWISE_OP:
	case NFTA_BITWISE_LEN:
		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
			abi_breakage();
		break;
	case NFTA_BITWISE_MASK:
	case NFTA_BITWISE_XOR:
	case NFTA_BITWISE_DATA:
		if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
			abi_breakage();
		break;
	}

	tb[type] = attr;
	return MNL_CB_OK;
}

static void
nftnl_expr_bitwise_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
	struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);

	if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG))
		mnl_attr_put_u32(nlh, NFTA_BITWISE_SREG, htonl(bitwise->sreg));
	if (e->flags & (1 << NFTNL_EXPR_BITWISE_DREG))
		mnl_attr_put_u32(nlh, NFTA_BITWISE_DREG, htonl(bitwise->dreg));
	if (e->flags & (1 << NFTNL_EXPR_BITWISE_OP))
		mnl_attr_put_u32(nlh, NFTA_BITWISE_OP, htonl(bitwise->op));
	if (e->flags & (1 << NFTNL_EXPR_BITWISE_LEN))
		mnl_attr_put_u32(nlh, NFTA_BITWISE_LEN, htonl(bitwise->len));
	if (e->flags & (1 << NFTNL_EXPR_BITWISE_MASK)) {
		struct nlattr *nest;

		nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_MASK);
		mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->mask.len,
			     bitwise->mask.val);
		mnl_attr_nest_end(nlh, nest);
	}
	if (e->flags & (1 << NFTNL_EXPR_BITWISE_XOR)) {
		struct nlattr *nest;

		nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_XOR);
		mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->xor.len,
			     bitwise->xor.val);
		mnl_attr_nest_end(nlh, nest);
	}
	if (e->flags & (1 << NFTNL_EXPR_BITWISE_DATA)) {
		struct nlattr *nest;

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

static int
nftnl_expr_bitwise_parse(struct nftnl_expr *e, struct nlattr *attr)
{
	struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
	struct nlattr *tb[NFTA_BITWISE_MAX+1] = {};
	int ret = 0;

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

	if (tb[NFTA_BITWISE_SREG]) {
		bitwise->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_SREG]));
		e->flags |= (1 << NFTNL_EXPR_BITWISE_SREG);
	}
	if (tb[NFTA_BITWISE_DREG]) {
		bitwise->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_DREG]));
		e->flags |= (1 << NFTNL_EXPR_BITWISE_DREG);
	}
	if (tb[NFTA_BITWISE_OP]) {
		bitwise->op = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_OP]));
		e->flags |= (1 << NFTNL_EXPR_BITWISE_OP);
	}
	if (tb[NFTA_BITWISE_LEN]) {
		bitwise->len = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_LEN]));
		e->flags |= (1 << NFTNL_EXPR_BITWISE_LEN);
	}
	if (tb[NFTA_BITWISE_MASK]) {
		ret = nftnl_parse_data(&bitwise->mask, tb[NFTA_BITWISE_MASK], NULL);
		e->flags |= (1 << NFTA_BITWISE_MASK);
	}
	if (tb[NFTA_BITWISE_XOR]) {
		ret = nftnl_parse_data(&bitwise->xor, tb[NFTA_BITWISE_XOR], NULL);
		e->flags |= (1 << NFTA_BITWISE_XOR);
	}
	if (tb[NFTA_BITWISE_DATA]) {
		ret = nftnl_parse_data(&bitwise->data, tb[NFTA_BITWISE_DATA], NULL);
		e->flags |= (1 << NFTNL_EXPR_BITWISE_DATA);
	}

	return ret;
}

static int
nftnl_expr_bitwise_snprintf_bool(char *buf, size_t size,
				 const struct nftnl_expr_bitwise *bitwise)
{
	int remain = size, offset = 0, ret;

	ret = snprintf(buf, remain, "reg %u = (reg=%u & ",
		       bitwise->dreg, bitwise->sreg);
	SNPRINTF_BUFFER_SIZE(ret, remain, offset);

	ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->mask,
				      NFTNL_OUTPUT_DEFAULT, 0, DATA_VALUE);
	SNPRINTF_BUFFER_SIZE(ret, remain, offset);

	ret = snprintf(buf + offset, remain, ") ^ ");
	SNPRINTF_BUFFER_SIZE(ret, remain, offset);

	ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->xor,
				      NFTNL_OUTPUT_DEFAULT, 0, DATA_VALUE);
	SNPRINTF_BUFFER_SIZE(ret, remain, offset);

	return offset;
}

static int
nftnl_expr_bitwise_snprintf_shift(char *buf, size_t size, const char *op,
				  const struct nftnl_expr_bitwise *bitwise)
{	int remain = size, offset = 0, ret;

	ret = snprintf(buf, remain, "reg %u = ( reg %u %s ",
		       bitwise->dreg, bitwise->sreg, op);
	SNPRINTF_BUFFER_SIZE(ret, remain, offset);

	ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->data,
				      NFTNL_OUTPUT_DEFAULT, 0, DATA_VALUE);
	SNPRINTF_BUFFER_SIZE(ret, remain, offset);

	ret = snprintf(buf + offset, remain, ") ");
	SNPRINTF_BUFFER_SIZE(ret, remain, offset);

	return offset;
}

static int nftnl_expr_bitwise_snprintf_default(char *buf, size_t size,
					       const struct nftnl_expr *e)
{
	struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
	int err = -1;

	switch (bitwise->op) {
	case NFT_BITWISE_BOOL:
		err = nftnl_expr_bitwise_snprintf_bool(buf, size, bitwise);
		break;
	case NFT_BITWISE_LSHIFT:
		err = nftnl_expr_bitwise_snprintf_shift(buf, size, "<<", bitwise);
		break;
	case NFT_BITWISE_RSHIFT:
		err = nftnl_expr_bitwise_snprintf_shift(buf, size, ">>", bitwise);
		break;
	}

	return err;
}

static int
nftnl_expr_bitwise_snprintf(char *buf, size_t size, uint32_t type,
			    uint32_t flags, const struct nftnl_expr *e)
{
	switch (type) {
	case NFTNL_OUTPUT_DEFAULT:
		return nftnl_expr_bitwise_snprintf_default(buf, size, e);
	default:
		break;
	}
	return -1;
}

struct expr_ops expr_ops_bitwise = {
	.name		= "bitwise",
	.alloc_len	= sizeof(struct nftnl_expr_bitwise),
	.max_attr	= NFTA_BITWISE_MAX,
	.set		= nftnl_expr_bitwise_set,
	.get		= nftnl_expr_bitwise_get,
	.parse		= nftnl_expr_bitwise_parse,
	.build		= nftnl_expr_bitwise_build,
	.snprintf	= nftnl_expr_bitwise_snprintf,
};