summaryrefslogtreecommitdiff
path: root/event_tagging.c
blob: b021e8c8dea22073fb67caec6af7768397160e20 (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
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
/*
 * Copyright (c) 2003-2009 Niels Provos <provos@citi.umich.edu>
 * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "event2/event-config.h"
#include "evconfig-private.h"

#ifdef EVENT__HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef EVENT__HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <windows.h>
#undef WIN32_LEAN_AND_MEAN
#endif

#ifdef EVENT__HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#include <sys/queue.h>
#ifdef EVENT__HAVE_SYS_TIME_H
#include <sys/time.h>
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef _WIN32
#include <syslog.h>
#endif
#ifdef EVENT__HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <limits.h>

#include "event2/event.h"
#include "event2/tag.h"
#include "event2/buffer.h"
#include "log-internal.h"
#include "mm-internal.h"
#include "util-internal.h"

/*
  Here's our wire format:

  Stream = TaggedData*

  TaggedData = Tag Length Data
       where the integer value of 'Length' is the length of 'data'.

  Tag = HByte* LByte
       where HByte is a byte with the high bit set, and LByte is a byte
       with the high bit clear. The integer value of the tag is taken
       by concatenating the lower 7 bits from all the tags.  So for example,
       the tag 0x66 is encoded as [66], whereas the tag 0x166 is encoded as
       [82 66]

  Length = Integer

  Integer = NNibbles Nibble* Padding?
       where NNibbles is a 4-bit value encoding the number of nibbles-1,
       and each Nibble is 4 bits worth of encoded integer, in big-endian
       order.  If the total encoded integer size is an odd number of nibbles,
       a final padding nibble with value 0 is appended.
*/

EVENT2_EXPORT_SYMBOL
int evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf);
EVENT2_EXPORT_SYMBOL
int evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf);
EVENT2_EXPORT_SYMBOL
int evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag);
EVENT2_EXPORT_SYMBOL
int evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf);

void
evtag_init(void)
{
}

/*
 * We encode integers by nibbles; the first nibble contains the number
 * of significant nibbles - 1;  this allows us to encode up to 64-bit
 * integers.  This function is byte-order independent.
 *
 * @param number a 32-bit unsigned integer to encode
 * @param data a pointer to where the data should be written.  Must
 *    have at least 5 bytes free.
 * @return the number of bytes written into data.
 */

#define ENCODE_INT_INTERNAL(data, number) do {				\
	int off = 1, nibbles = 0;					\
									\
	memset(data, 0, sizeof(number)+1);				\
	while (number) {						\
		if (off & 0x1)						\
			data[off/2] = (data[off/2] & 0xf0) | (number & 0x0f); \
		else							\
			data[off/2] = (data[off/2] & 0x0f) |		\
			    ((number & 0x0f) << 4);			\
		number >>= 4;						\
		off++;							\
	}								\
									\
	if (off > 2)							\
		nibbles = off - 2;					\
									\
	/* Off - 1 is the number of encoded nibbles */			\
	data[0] = (data[0] & 0x0f) | ((nibbles & 0x0f) << 4);		\
									\
	return ((off + 1) / 2);						\
} while (0)

static inline int
encode_int_internal(ev_uint8_t *data, ev_uint32_t number)
{
	ENCODE_INT_INTERNAL(data, number);
}

static inline int
encode_int64_internal(ev_uint8_t *data, ev_uint64_t number)
{
	ENCODE_INT_INTERNAL(data, number);
}

void
evtag_encode_int(struct evbuffer *evbuf, ev_uint32_t number)
{
	ev_uint8_t data[5];
	int len = encode_int_internal(data, number);
	evbuffer_add(evbuf, data, len);
}

void
evtag_encode_int64(struct evbuffer *evbuf, ev_uint64_t number)
{
	ev_uint8_t data[9];
	int len = encode_int64_internal(data, number);
	evbuffer_add(evbuf, data, len);
}

/*
 * Support variable length encoding of tags; we use the high bit in each
 * octet as a continuation signal.
 */

int
evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag)
{
	int bytes = 0;
	ev_uint8_t data[5];

	memset(data, 0, sizeof(data));
	do {
		ev_uint8_t lower = tag & 0x7f;
		tag >>= 7;

		if (tag)
			lower |= 0x80;

		data[bytes++] = lower;
	} while (tag);

	if (evbuf != NULL)
		evbuffer_add(evbuf, data, bytes);

	return (bytes);
}

static int
decode_tag_internal(ev_uint32_t *ptag, struct evbuffer *evbuf, int dodrain)
{
	ev_uint32_t number = 0;
	size_t len = evbuffer_get_length(evbuf);
	ev_uint8_t *data;
	size_t count = 0;
	int  shift = 0, done = 0;

	/*
	 * the encoding of a number is at most one byte more than its
	 * storage size.  however, it may also be much smaller.
	 */
	data = evbuffer_pullup(
		evbuf, len < sizeof(number) + 1 ? len : sizeof(number) + 1);
	if (!data)
		return (-1);

	while (count++ < len) {
		ev_uint8_t lower = *data++;
		if (shift >= 28) {
			/* Make sure it fits into 32 bits */
			if (shift > 28)
				return (-1);
			if ((lower & 0x7f) > 15)
				return (-1);
		}
		number |= (lower & (unsigned)0x7f) << shift;
		shift += 7;

		if (!(lower & 0x80)) {
			done = 1;
			break;
		}
	}

	if (!done)
		return (-1);

	if (dodrain)
		evbuffer_drain(evbuf, count);

	if (ptag != NULL)
		*ptag = number;

	return count > INT_MAX ? INT_MAX : (int)(count);
}

int
evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf)
{
	return (decode_tag_internal(ptag, evbuf, 1 /* dodrain */));
}

/*
 * Marshal a data type, the general format is as follows:
 *
 * tag number: one byte; length: var bytes; payload: var bytes
 */

void
evtag_marshal(struct evbuffer *evbuf, ev_uint32_t tag,
    const void *data, ev_uint32_t len)
{
	evtag_encode_tag(evbuf, tag);
	evtag_encode_int(evbuf, len);
	evbuffer_add(evbuf, (void *)data, len);
}

void
evtag_marshal_buffer(struct evbuffer *evbuf, ev_uint32_t tag,
    struct evbuffer *data)
{
	evtag_encode_tag(evbuf, tag);
	/* XXX support more than UINT32_MAX data */
	evtag_encode_int(evbuf, (ev_uint32_t)evbuffer_get_length(data));
	evbuffer_add_buffer(evbuf, data);
}

/* Marshaling for integers */
void
evtag_marshal_int(struct evbuffer *evbuf, ev_uint32_t tag, ev_uint32_t integer)
{
	ev_uint8_t data[5];
	int len = encode_int_internal(data, integer);

	evtag_encode_tag(evbuf, tag);
	evtag_encode_int(evbuf, len);
	evbuffer_add(evbuf, data, len);
}

void
evtag_marshal_int64(struct evbuffer *evbuf, ev_uint32_t tag,
    ev_uint64_t integer)
{
	ev_uint8_t data[9];
	int len = encode_int64_internal(data, integer);

	evtag_encode_tag(evbuf, tag);
	evtag_encode_int(evbuf, len);
	evbuffer_add(evbuf, data, len);
}

void
evtag_marshal_string(struct evbuffer *buf, ev_uint32_t tag, const char *string)
{
	/* TODO support strings longer than UINT32_MAX ? */
	evtag_marshal(buf, tag, string, (ev_uint32_t)strlen(string));
}

void
evtag_marshal_timeval(struct evbuffer *evbuf, ev_uint32_t tag, struct timeval *tv)
{
	ev_uint8_t data[10];
	int len = encode_int_internal(data, tv->tv_sec);
	len += encode_int_internal(data + len, tv->tv_usec);
	evtag_marshal(evbuf, tag, data, len);
}

#define DECODE_INT_INTERNAL(number, maxnibbles, pnumber, evbuf, offset) \
do {									\
	ev_uint8_t *data;						\
	ev_ssize_t len = evbuffer_get_length(evbuf) - offset;		\
	int nibbles = 0;						\
									\
	if (len <= 0)							\
		return (-1);						\
									\
	/* XXX(niels): faster? */					\
	data = evbuffer_pullup(evbuf, offset + 1) + offset;		\
	if (!data)							\
		return (-1);						\
									\
	nibbles = ((data[0] & 0xf0) >> 4) + 1;				\
	if (nibbles > maxnibbles || (nibbles >> 1) + 1 > len)		\
		return (-1);						\
	len = (nibbles >> 1) + 1;					\
									\
	data = evbuffer_pullup(evbuf, offset + len) + offset;		\
	if (!data)							\
		return (-1);						\
									\
	while (nibbles > 0) {						\
		number <<= 4;						\
		if (nibbles & 0x1)					\
			number |= data[nibbles >> 1] & 0x0f;		\
		else							\
			number |= (data[nibbles >> 1] & 0xf0) >> 4;	\
		nibbles--;						\
	}								\
									\
	*pnumber = number;						\
									\
	return (int)(len);						\
} while (0)

/* Internal: decode an integer from an evbuffer, without draining it.
 *  Only integers up to 32-bits are supported.
 *
 * @param evbuf the buffer to read from
 * @param offset an index into the buffer at which we should start reading.
 * @param pnumber a pointer to receive the integer.
 * @return The length of the number as encoded, or -1 on error.
 */

static int
decode_int_internal(ev_uint32_t *pnumber, struct evbuffer *evbuf, int offset)
{
	ev_uint32_t number = 0;
	DECODE_INT_INTERNAL(number, 8, pnumber, evbuf, offset);
}

static int
decode_int64_internal(ev_uint64_t *pnumber, struct evbuffer *evbuf, int offset)
{
	ev_uint64_t number = 0;
	DECODE_INT_INTERNAL(number, 16, pnumber, evbuf, offset);
}

int
evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf)
{
	int res = decode_int_internal(pnumber, evbuf, 0);
	if (res != -1)
		evbuffer_drain(evbuf, res);

	return (res == -1 ? -1 : 0);
}

int
evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf)
{
	int res = decode_int64_internal(pnumber, evbuf, 0);
	if (res != -1)
		evbuffer_drain(evbuf, res);

	return (res == -1 ? -1 : 0);
}

int
evtag_peek(struct evbuffer *evbuf, ev_uint32_t *ptag)
{
	return (decode_tag_internal(ptag, evbuf, 0 /* dodrain */));
}

int
evtag_peek_length(struct evbuffer *evbuf, ev_uint32_t *plength)
{
	int res, len;

	len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */);
	if (len == -1)
		return (-1);

	res = decode_int_internal(plength, evbuf, len);
	if (res == -1)
		return (-1);

	*plength += res + len;

	return (0);
}

int
evtag_payload_length(struct evbuffer *evbuf, ev_uint32_t *plength)
{
	int res, len;

	len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */);
	if (len == -1)
		return (-1);

	res = decode_int_internal(plength, evbuf, len);
	if (res == -1)
		return (-1);

	return (0);
}

/* just unmarshals the header and returns the length of the remaining data */

int
evtag_unmarshal_header(struct evbuffer *evbuf, ev_uint32_t *ptag)
{
	ev_uint32_t len;

	if (decode_tag_internal(ptag, evbuf, 1 /* dodrain */) == -1)
		return (-1);
	if (evtag_decode_int(&len, evbuf) == -1)
		return (-1);

	if (evbuffer_get_length(evbuf) < len)
		return (-1);

	return (len);
}

int
evtag_consume(struct evbuffer *evbuf)
{
	int len;
	if ((len = evtag_unmarshal_header(evbuf, NULL)) == -1)
		return (-1);
	evbuffer_drain(evbuf, len);

	return (0);
}

/* Reads the data type from an event buffer */

int
evtag_unmarshal(struct evbuffer *src, ev_uint32_t *ptag, struct evbuffer *dst)
{
	int len;

	if ((len = evtag_unmarshal_header(src, ptag)) == -1)
		return (-1);

	if (evbuffer_add(dst, evbuffer_pullup(src, len), len) == -1)
		return (-1);

	evbuffer_drain(src, len);

	return (len);
}

/* Marshaling for integers */

int
evtag_unmarshal_int(struct evbuffer *evbuf, ev_uint32_t need_tag,
    ev_uint32_t *pinteger)
{
	ev_uint32_t tag;
	ev_uint32_t len;
	int result;

	if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1)
		return (-1);
	if (need_tag != tag)
		return (-1);
	if (evtag_decode_int(&len, evbuf) == -1)
		return (-1);

	if (evbuffer_get_length(evbuf) < len)
		return (-1);

	result = decode_int_internal(pinteger, evbuf, 0);
	evbuffer_drain(evbuf, len);
	if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/
		return (-1);
	else
		return result;
}

int
evtag_unmarshal_int64(struct evbuffer *evbuf, ev_uint32_t need_tag,
    ev_uint64_t *pinteger)
{
	ev_uint32_t tag;
	ev_uint32_t len;
	int result;

	if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1)
		return (-1);
	if (need_tag != tag)
		return (-1);
	if (evtag_decode_int(&len, evbuf) == -1)
		return (-1);

	if (evbuffer_get_length(evbuf) < len)
		return (-1);

	result = decode_int64_internal(pinteger, evbuf, 0);
	evbuffer_drain(evbuf, len);
	if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/
		return (-1);
	else
		return result;
}

/* Unmarshal a fixed length tag */

int
evtag_unmarshal_fixed(struct evbuffer *src, ev_uint32_t need_tag, void *data,
    size_t len)
{
	ev_uint32_t tag;
	int tag_len;

	/* Now unmarshal a tag and check that it matches the tag we want */
	if ((tag_len = evtag_unmarshal_header(src, &tag)) < 0 ||
	    tag != need_tag)
		return (-1);

	if ((size_t)tag_len != len)
		return (-1);

	evbuffer_remove(src, data, len);
	return (0);
}

int
evtag_unmarshal_string(struct evbuffer *evbuf, ev_uint32_t need_tag,
    char **pstring)
{
	ev_uint32_t tag;
	int tag_len;

	if ((tag_len = evtag_unmarshal_header(evbuf, &tag)) == -1 ||
	    tag != need_tag)
		return (-1);

	*pstring = mm_malloc(tag_len + 1);
	if (*pstring == NULL) {
		event_warn("%s: malloc", __func__);
		return -1;
	}
	evbuffer_remove(evbuf, *pstring, tag_len);
	(*pstring)[tag_len] = '\0';

	return (0);
}

int
evtag_unmarshal_timeval(struct evbuffer *evbuf, ev_uint32_t need_tag,
    struct timeval *ptv)
{
	ev_uint32_t tag;
	ev_uint32_t integer;
	int len, offset, offset2;
	int result = -1;

	if ((len = evtag_unmarshal_header(evbuf, &tag)) == -1)
		return (-1);
	if (tag != need_tag)
		goto done;
	if ((offset = decode_int_internal(&integer, evbuf, 0)) == -1)
		goto done;
	ptv->tv_sec = integer;
	if ((offset2 = decode_int_internal(&integer, evbuf, offset)) == -1)
		goto done;
	ptv->tv_usec = integer;
	if (offset + offset2 > len) /* XXX Should this be != instead of > ? */
		goto done;

	result = 0;
 done:
	evbuffer_drain(evbuf, len);
	return result;
}