summaryrefslogtreecommitdiffstats
path: root/src/libnetfilter_acct.c
blob: 7f539b6f79561f2345db9eec3b7f0e70d07a52ae (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
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
/*
 * (C) 2011 by Pablo Neira Ayuso <pablo@netfilter.org>
 * (C) 2011 by Intra2net AG <http://www.intra2net.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the Lesser GNU General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 */
#include "internal.h"

#include <time.h>
#include <endian.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>

#include <libmnl/libmnl.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_acct.h>

#include <libnetfilter_acct/libnetfilter_acct.h>

/**
 * \mainpage
 *
 * libnetfilter_acct is the userspace library that provides a programming
 * interface (API) to the extended accounting infrastructure. Basically, you
 * can find here a set of helper functions that you can use together with
 * libmnl.
 *
 * libnetfilter_acct homepage is:
 *      http://netfilter.org/projects/libnetfilter_acct/
 *
 * \section Dependencies
 * libnetfilter_acct requires libmnl >= 1.0.0 and the Linux kernel that
 * includes the nfnetlink_acct subsystem (i.e. 3.3.x or any later).
 *
 * \section Main Features
 *  - listing/retrieving existing accounting objects.
 *  - atomically retrieving and reset accounting objects.
 *  - inserting/modifying/deleting accounting objects.
 *
 * \section Git Tree
 * The current development version of libnetfilter_acct can be accessed at
 * https://git.netfilter.org/cgi-bin/gitweb.cgi?p=libnetfilter_acct.git
 *
 * \section using Using libnetfilter_acct
 * To write your own program using libnetfilter_acct, you should start by
 * reading the documentation for libmnl to understand basic operation with
 * Netlink sockets. Moreover, you may want to check the examples available
 * under examples/ in the libnetfilter_acct source code. You can compile
 * these examples by invoking `make check'.
 *
 * \section Authors
 * libnetfilter_acct has been written by Pablo Neira Ayuso.
 */

struct nfacct {
	char		name[NFACCT_NAME_MAX];
	uint64_t	pkts;
	uint64_t	bytes;
	uint32_t	bitset;
	uint32_t	flags;
	uint64_t	quota;
};

/**
 * \defgroup nfacct Accounting object handling
 * @{
 */

/**
 * nfacct_alloc - allocate a new accounting object
 *
 * In case of success, this function returns a valid pointer, otherwise NULL
 * s returned and errno is appropriately set.
 */
struct nfacct *nfacct_alloc(void)
{
	return calloc(1, sizeof(struct nfacct));
}
EXPORT_SYMBOL(nfacct_alloc);

/**
 * nfacct_free - release one accounting object
 * \param nfacct pointer to the accounting object
 */
void nfacct_free(struct nfacct *nfacct)
{
	free(nfacct);
}
EXPORT_SYMBOL(nfacct_free);

/**
 * nfacct_attr_set - set one attribute of the accounting object
 * \param nfacct pointer to the accounting object
 * \param type attribute type you want to set
 * \param data pointer to data that will be used to set this attribute
 */
void
nfacct_attr_set(struct nfacct *nfacct, enum nfacct_attr_type type,
		const void *data)
{
	switch(type) {
	case NFACCT_ATTR_NAME:
		strncpy(nfacct->name, data, NFACCT_NAME_MAX);
		nfacct->name[NFACCT_NAME_MAX-1] = '\0';
		nfacct->bitset |= (1 << NFACCT_ATTR_NAME);
		break;
	case NFACCT_ATTR_PKTS:
		nfacct->pkts = *((uint64_t *) data);
		nfacct->bitset |= (1 << NFACCT_ATTR_PKTS);
		break;
	case NFACCT_ATTR_BYTES:
		nfacct->bytes = *((uint64_t *) data);
		nfacct->bitset |= (1 << NFACCT_ATTR_BYTES);
		break;
	case NFACCT_ATTR_FLAGS:
		nfacct->flags = *((uint32_t *) data);
		nfacct->bitset |= (1 << NFACCT_ATTR_FLAGS);
		break;
	case NFACCT_ATTR_QUOTA:
		nfacct->quota = *((uint64_t *) data);
		nfacct->bitset |= (1 << NFACCT_ATTR_QUOTA);
		break;
	}
}
EXPORT_SYMBOL(nfacct_attr_set);

/**
 * nfacct_attr_set_str - set one attribute the accounting object
 * \param nfacct pointer to the accounting object
 * \param type attribute type you want to set
 * \param name string that will be used to set this attribute
 */
void
nfacct_attr_set_str(struct nfacct *nfacct, enum nfacct_attr_type type,
		    const char *name)
{
	nfacct_attr_set(nfacct, type, name);
}
EXPORT_SYMBOL(nfacct_attr_set_str);

/**
 * nfacct_attr_set_u64 - set one attribute the accounting object
 * \param nfacct pointer to the accounting object
 * \param type attribute type you want to set
 * \param value unsigned 64-bits integer
 */
void
nfacct_attr_set_u64(struct nfacct *nfacct, enum nfacct_attr_type type,
		    uint64_t value)
{
	nfacct_attr_set(nfacct, type, &value);
}
EXPORT_SYMBOL(nfacct_attr_set_u64);

/**
 * nfacct_attr_unset - unset one attribute the accounting object
 * \param nfacct pointer to the accounting object
 * \param type attribute type you want to set
 */
void
nfacct_attr_unset(struct nfacct *nfacct, enum nfacct_attr_type type)
{
	switch(type) {
	case NFACCT_ATTR_NAME:
		nfacct->bitset &= ~(1 << NFACCT_ATTR_NAME);
		break;
	case NFACCT_ATTR_PKTS:
		nfacct->bitset &= ~(1 << NFACCT_ATTR_PKTS);
		break;
	case NFACCT_ATTR_BYTES:
		nfacct->bitset &= ~(1 << NFACCT_ATTR_BYTES);
		break;
	case NFACCT_ATTR_FLAGS:
		nfacct->bitset &= ~(1 << NFACCT_ATTR_FLAGS);
		break;
	case NFACCT_ATTR_QUOTA:
		nfacct->bitset &= ~(1 << NFACCT_ATTR_QUOTA);
		break;
	}
}
EXPORT_SYMBOL(nfacct_attr_unset);

/**
 * nfacct_attr_get - get one attribute the accounting object
 * \param nfacct pointer to the accounting object
 * \param type attribute type you want to set
 *
 * This function returns a valid pointer to the attribute data. If a
 * unsupported attribute is used, this returns NULL.
 */
const void *nfacct_attr_get(struct nfacct *nfacct, enum nfacct_attr_type type)
{
	const void *ret = NULL;

	switch(type) {
	case NFACCT_ATTR_NAME:
		if (nfacct->bitset & (1 << NFACCT_ATTR_NAME))
			ret = nfacct->name;
		break;
	case NFACCT_ATTR_PKTS:
		if (nfacct->bitset & (1 << NFACCT_ATTR_PKTS))
			ret = &nfacct->pkts;
		break;
	case NFACCT_ATTR_BYTES:
		if (nfacct->bitset & (1 << NFACCT_ATTR_BYTES))
			ret = &nfacct->bytes;
		break;
	case NFACCT_ATTR_FLAGS:
		if (nfacct->bitset & (1 << NFACCT_ATTR_FLAGS))
			ret = &nfacct->flags;
		break;
	case NFACCT_ATTR_QUOTA:
		if (nfacct->bitset & (1 << NFACCT_ATTR_QUOTA))
			ret = &nfacct->quota;
		break;
	}
	return ret;
}
EXPORT_SYMBOL(nfacct_attr_get);

/**
 * nfacct_attr_get_str - get one attribute the accounting object
 * \param nfacct pointer to the accounting object
 * \param type attribute type you want to set
 *
 * This function returns a valid pointer to the beginning of the string.
 * If the attribute is unsupported, this returns NULL.
 */
const char *
nfacct_attr_get_str(struct nfacct *nfacct, enum nfacct_attr_type type)
{
	return nfacct_attr_get(nfacct, type);
}
EXPORT_SYMBOL(nfacct_attr_get_str);

/**
 * nfacct_attr_get_u64 - get one attribute the accounting object
 * \param nfacct pointer to the accounting object
 * \param type attribute type you want to set
 *
 * This function returns a unsigned 64-bits integer. If the attribute is
 * unsupported, this returns NULL.
 */
uint64_t nfacct_attr_get_u64(struct nfacct *nfacct, enum nfacct_attr_type type)
{
	const void *ret = nfacct_attr_get(nfacct, type);
	return ret ? *((uint64_t *)ret) : 0;
}
EXPORT_SYMBOL(nfacct_attr_get_u64);

static int
nfacct_snprintf_plain(char *buf, size_t rem, struct nfacct *nfacct,
		      uint16_t flags)
{
	int ret, offset = 0, len = 0;

	if (flags & NFACCT_SNPRINTF_F_FULL) {
		ret = snprintf(buf, rem,
			"{ pkts = %.20"PRIu64", bytes = %.20"PRIu64"",
			nfacct_attr_get_u64(nfacct, NFACCT_ATTR_PKTS),
			nfacct_attr_get_u64(nfacct, NFACCT_ATTR_BYTES));
		SNPRINTF_CHECK(ret, rem, offset, len);

		if (nfacct->flags) {
			uint32_t mode;

			mode = nfacct_attr_get_u64(nfacct, NFACCT_ATTR_FLAGS);

			ret = snprintf(buf + offset, rem,
				", quota = %.20"PRIu64", mode = %s",
				nfacct_attr_get_u64(nfacct, NFACCT_ATTR_QUOTA),
				mode == NFACCT_F_QUOTA_BYTES ?
				"byte" : "packet");
			SNPRINTF_CHECK(ret, rem, offset, len);
		}

		ret = snprintf(buf + offset, rem, " } = %s;",
			nfacct_attr_get_str(nfacct, NFACCT_ATTR_NAME));
	} else {
		ret = snprintf(buf, rem, "%s\n",
			nfacct_attr_get_str(nfacct, NFACCT_ATTR_NAME));
	}
	SNPRINTF_CHECK(ret, rem, offset, len);

	return len;
}

#define BUFFER_SIZE(ret, size, rem, offset)		\
	size += ret;					\
	if (ret > rem)					\
		ret = rem;				\
	offset += ret;					\
	rem -= ret;

static int
nfacct_snprintf_xml_localtime(char *buf, unsigned int rem, const struct tm *tm)
{
        int ret = 0;
        unsigned int size = 0, offset = 0;

        ret = snprintf(buf+offset, rem, "<hour>%d</hour>", tm->tm_hour);
        BUFFER_SIZE(ret, size, rem, offset);

        ret = snprintf(buf+offset, rem, "<min>%02d</min>", tm->tm_min);
        BUFFER_SIZE(ret, size, rem, offset);

        ret = snprintf(buf+offset, rem, "<sec>%02d</sec>", tm->tm_sec);
        BUFFER_SIZE(ret, size, rem, offset);

        ret = snprintf(buf+offset, rem, "<wday>%d</wday>", tm->tm_wday + 1);
        BUFFER_SIZE(ret, size, rem, offset);

        ret = snprintf(buf+offset, rem, "<day>%d</day>", tm->tm_mday);
        BUFFER_SIZE(ret, size, rem, offset);

        ret = snprintf(buf+offset, rem, "<month>%d</month>", tm->tm_mon + 1);
        BUFFER_SIZE(ret, size, rem, offset);

        ret = snprintf(buf+offset, rem, "<year>%d</year>", 1900 + tm->tm_year);
        BUFFER_SIZE(ret, size, rem, offset);

        return size;
}


static int
nfacct_snprintf_xml(char *buf, size_t rem, struct nfacct *nfacct,
		    uint16_t flags)
{
	int ret = 0;
	unsigned int size = 0, offset = 0;

	ret = snprintf(buf, rem,
			"<obj><name>%s</name>"
			"<pkts>%.20"PRIu64"</pkts>"
			"<bytes>%.20"PRIu64"</bytes>",
			nfacct_attr_get_str(nfacct, NFACCT_ATTR_NAME),
			nfacct_attr_get_u64(nfacct, NFACCT_ATTR_PKTS),
			nfacct_attr_get_u64(nfacct, NFACCT_ATTR_BYTES));
	BUFFER_SIZE(ret, size, rem, offset);

	if (flags & NFACCT_SNPRINTF_F_TIME) {
		time_t t;
		struct tm tm;

		t = time(NULL);
		if (localtime_r(&t, &tm) == NULL)
			goto err;

		ret = nfacct_snprintf_xml_localtime(buf+offset, rem, &tm);
	        BUFFER_SIZE(ret, size, rem, offset);
	}

	ret = snprintf(buf+offset, rem, "</obj>");
	BUFFER_SIZE(ret, size, rem, offset);

err:
	return ret;
}

/**
 * nfacct_snprintf - print accounting object into one buffer
 * \param buf: pointer to buffer that is used to print the object
 * \param size: size of the buffer (or remaining room in it).
 * \param nfacct: pointer to a valid accounting object.
 * \param type: format output type, NFACCT_SNPRINTF_T_[PLAIN|XML]
 * \param flags: output flags (NFACCT_SNPRINTF_F_FULL).
 *
 * This function returns -1 in case that some mandatory attributes are
 * missing. On sucess, it returns 0.
 */
int nfacct_snprintf(char *buf, size_t size, struct nfacct *nfacct,
		    uint16_t type, uint16_t flags)
{
	int ret = 0;

	switch(type) {
	case NFACCT_SNPRINTF_T_PLAIN:
		ret = nfacct_snprintf_plain(buf, size, nfacct, flags);
		break;
	case NFACCT_SNPRINTF_T_XML:
		ret = nfacct_snprintf_xml(buf, size, nfacct, flags);
		break;
	default:
		ret = -1;
		break;
	}
	return ret;
}
EXPORT_SYMBOL(nfacct_snprintf);

/**
 * @}
 */

/**
 * \defgroup nlmsg Netlink message helper functions
 * @{
 */

/**
 * nfacct_nlmsg_build_hdr - build netlink message header for nfacct subsystem
 * \param buf: buffer where this function outputs the netlink message.
 * \param cmd: nfacct nfnetlink command.
 * \param flags: netlink flags.
 * \param seq: sequence number for this message.
 *
 * Possible commands:
 * - NFNL_MSG_ACCT_NEW: new accounting object.
 * - NFNL_MSG_ACCT_GET: get accounting object.
 * - NFNL_MSG_ACCT_GET_CTRZERO: get accounting object and atomically reset.
 *
 * Examples:
 * - Command NFNL_MSG_ACCT_NEW + flags NLM_F_CREATE | NLM_F_ACK, to create
 *   one new accounting object (if it does not already exists). You receive
 *   one acknoledgment in any case with the result of the operation.
 *
 * - Command NFNL_MSG_ACCT_GET + flags NLM_F_DUMP, to obtain all the
 *   existing accounting objects.
 *
 * - Command NFNL_MSG_ACCT_GET_CTRZERO + flags NLM_F_DUMP, to atomically
 *   obtain all the existing accounting objects and reset them.
 *
 * - Command NFNL_MSG_ACCT_DEL, to delete all existing unused objects.
 *
 * - Command NFNL_MSG_ACCT_DEL, to delete one specific nfacct object (if
 *   unused, otherwise you hit EBUSY).
 */
struct nlmsghdr *
nfacct_nlmsg_build_hdr(char *buf, uint8_t cmd, uint16_t flags, uint32_t seq)
{
	struct nlmsghdr *nlh;
	struct nfgenmsg *nfh;

	nlh = mnl_nlmsg_put_header(buf);
	nlh->nlmsg_type = (NFNL_SUBSYS_ACCT << 8) | cmd;
	nlh->nlmsg_flags = NLM_F_REQUEST | flags;
	nlh->nlmsg_seq = seq;

	nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
	nfh->nfgen_family = AF_UNSPEC;
	nfh->version = NFNETLINK_V0;
	nfh->res_id = 0;

	return nlh;
}
EXPORT_SYMBOL(nfacct_nlmsg_build_hdr);

/**
 * nfacct_nlmsg_build_payload - build payload from accounting object
 * \param nlh: netlink message that you want to use to add the payload.
 * \param nfacct: pointer to a accounting object
 */
void nfacct_nlmsg_build_payload(struct nlmsghdr *nlh, struct nfacct *nfacct)
{
	if (nfacct->bitset & (1 << NFACCT_ATTR_NAME))
		mnl_attr_put_strz(nlh, NFACCT_NAME, nfacct->name);

	if (nfacct->bitset & (1 << NFACCT_ATTR_PKTS))
		mnl_attr_put_u64(nlh, NFACCT_PKTS, htobe64(nfacct->pkts));

	if (nfacct->bitset & (1 << NFACCT_ATTR_BYTES))
		mnl_attr_put_u64(nlh, NFACCT_BYTES, htobe64(nfacct->bytes));

	if (nfacct->bitset & (1 << NFACCT_ATTR_FLAGS))
		mnl_attr_put_u32(nlh, NFACCT_FLAGS, htobe32(nfacct->flags));

	if (nfacct->bitset & (1 << NFACCT_ATTR_QUOTA))
		mnl_attr_put_u64(nlh, NFACCT_QUOTA, htobe64(nfacct->quota));
}
EXPORT_SYMBOL(nfacct_nlmsg_build_payload);

static int nfacct_nlmsg_parse_attr_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, NFACCT_MAX) < 0)
		return MNL_CB_OK;

	switch(type) {
	case NFACCT_NAME:
		if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	case NFACCT_PKTS:
	case NFACCT_BYTES:
		if (mnl_attr_validate(attr, MNL_TYPE_U64) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	}
	tb[type] = attr;
	return MNL_CB_OK;
}

/**
 * nfacct_nlmsg_parse_payload - set accounting object attributes from message
 * \param nlh: netlink message that you want to use to add the payload.
 * \param nfacct: pointer to a accounting object
 *
 * This function returns -1 in case that some mandatory attributes are
 * missing. On sucess, it returns 0.
 */
int
nfacct_nlmsg_parse_payload(const struct nlmsghdr *nlh, struct nfacct *nfacct)
{
	struct nlattr *tb[NFACCT_MAX+1] = {};
	struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);

	mnl_attr_parse(nlh, sizeof(*nfg), nfacct_nlmsg_parse_attr_cb, tb);
	if (!tb[NFACCT_NAME] && !tb[NFACCT_PKTS] && !tb[NFACCT_BYTES])
		return -1;

	nfacct_attr_set_str(nfacct, NFACCT_ATTR_NAME,
			    mnl_attr_get_str(tb[NFACCT_NAME]));
	nfacct_attr_set_u64(nfacct, NFACCT_ATTR_PKTS,
			    be64toh(mnl_attr_get_u64(tb[NFACCT_PKTS])));
	nfacct_attr_set_u64(nfacct, NFACCT_ATTR_BYTES,
			    be64toh(mnl_attr_get_u64(tb[NFACCT_BYTES])));

	if (tb[NFACCT_FLAGS] && tb[NFACCT_QUOTA]) {
		uint32_t flags = be32toh(mnl_attr_get_u32(tb[NFACCT_FLAGS]));
		nfacct_attr_set(nfacct, NFACCT_ATTR_FLAGS, &flags);
		nfacct_attr_set_u64(nfacct, NFACCT_ATTR_QUOTA,
			    be64toh(mnl_attr_get_u64(tb[NFACCT_QUOTA])));
	}

	return 0;
}
EXPORT_SYMBOL(nfacct_nlmsg_parse_payload);

/**
 * @}
 */