1/*
2 * Copyright (c) 2003, 2004 Niels Provos <provos@citi.umich.edu>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 *    derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#ifdef HAVE_SYS_TYPES_H
33#include <sys/types.h>
34#endif
35#ifdef HAVE_SYS_PARAM_H
36#include <sys/param.h>
37#endif
38
39#ifdef WIN32
40#define WIN32_LEAN_AND_MEAN
41#include <winsock2.h>
42#include <windows.h>
43#undef WIN32_LEAN_AND_MEAN
44#else
45#include <sys/ioctl.h>
46#endif
47
48#include <sys/queue.h>
49#ifdef HAVE_SYS_TIME_H
50#include <sys/time.h>
51#endif
52
53#include <errno.h>
54#include <stdio.h>
55#include <stdlib.h>
56#include <string.h>
57#ifndef WIN32
58#include <syslog.h>
59#endif
60#ifdef HAVE_UNISTD_H
61#include <unistd.h>
62#endif
63
64#include "event.h"
65#include "evutil.h"
66#include "log.h"
67
68int evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf);
69int evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag);
70int evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf);
71
72static struct evbuffer *_buf;	/* not thread safe */
73
74void
75evtag_init(void)
76{
77	if (_buf != NULL)
78		return;
79
80	if ((_buf = evbuffer_new()) == NULL)
81		event_err(1, "%s: malloc", __func__);
82}
83
84/*
85 * We encode integer's by nibbles; the first nibble contains the number
86 * of significant nibbles - 1;  this allows us to encode up to 64-bit
87 * integers.  This function is byte-order independent.
88 */
89
90void
91encode_int(struct evbuffer *evbuf, ev_uint32_t number)
92{
93	int off = 1, nibbles = 0;
94	ev_uint8_t data[5];
95
96	memset(data, 0, sizeof(ev_uint32_t)+1);
97	while (number) {
98		if (off & 0x1)
99			data[off/2] = (data[off/2] & 0xf0) | (number & 0x0f);
100		else
101			data[off/2] = (data[off/2] & 0x0f) |
102			    ((number & 0x0f) << 4);
103		number >>= 4;
104		off++;
105	}
106
107	if (off > 2)
108		nibbles = off - 2;
109
110	/* Off - 1 is the number of encoded nibbles */
111	data[0] = (data[0] & 0x0f) | ((nibbles & 0x0f) << 4);
112
113	evbuffer_add(evbuf, data, (off + 1) / 2);
114}
115
116/*
117 * Support variable length encoding of tags; we use the high bit in each
118 * octet as a continuation signal.
119 */
120
121int
122evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag)
123{
124	int bytes = 0;
125	ev_uint8_t data[5];
126
127	memset(data, 0, sizeof(data));
128	do {
129		ev_uint8_t lower = tag & 0x7f;
130		tag >>= 7;
131
132		if (tag)
133			lower |= 0x80;
134
135		data[bytes++] = lower;
136	} while (tag);
137
138	if (evbuf != NULL)
139		evbuffer_add(evbuf, data, bytes);
140
141	return (bytes);
142}
143
144static int
145decode_tag_internal(ev_uint32_t *ptag, struct evbuffer *evbuf, int dodrain)
146{
147	ev_uint32_t number = 0;
148	ev_uint8_t *data = EVBUFFER_DATA(evbuf);
149	int len = EVBUFFER_LENGTH(evbuf);
150	int count = 0, shift = 0, done = 0;
151
152	while (count++ < len) {
153		ev_uint8_t lower = *data++;
154		number |= (lower & 0x7f) << shift;
155		shift += 7;
156
157		if (!(lower & 0x80)) {
158			done = 1;
159			break;
160		}
161	}
162
163	if (!done)
164		return (-1);
165
166	if (dodrain)
167		evbuffer_drain(evbuf, count);
168
169	if (ptag != NULL)
170		*ptag = number;
171
172	return (count);
173}
174
175int
176evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf)
177{
178	return (decode_tag_internal(ptag, evbuf, 1 /* dodrain */));
179}
180
181/*
182 * Marshal a data type, the general format is as follows:
183 *
184 * tag number: one byte; length: var bytes; payload: var bytes
185 */
186
187void
188evtag_marshal(struct evbuffer *evbuf, ev_uint32_t tag,
189    const void *data, ev_uint32_t len)
190{
191	evtag_encode_tag(evbuf, tag);
192	encode_int(evbuf, len);
193	evbuffer_add(evbuf, (void *)data, len);
194}
195
196/* Marshaling for integers */
197void
198evtag_marshal_int(struct evbuffer *evbuf, ev_uint32_t tag, ev_uint32_t integer)
199{
200	evbuffer_drain(_buf, EVBUFFER_LENGTH(_buf));
201	encode_int(_buf, integer);
202
203	evtag_encode_tag(evbuf, tag);
204	encode_int(evbuf, EVBUFFER_LENGTH(_buf));
205	evbuffer_add_buffer(evbuf, _buf);
206}
207
208void
209evtag_marshal_string(struct evbuffer *buf, ev_uint32_t tag, const char *string)
210{
211	evtag_marshal(buf, tag, string, strlen(string));
212}
213
214void
215evtag_marshal_timeval(struct evbuffer *evbuf, ev_uint32_t tag, struct timeval *tv)
216{
217	evbuffer_drain(_buf, EVBUFFER_LENGTH(_buf));
218
219	encode_int(_buf, tv->tv_sec);
220	encode_int(_buf, tv->tv_usec);
221
222	evtag_marshal(evbuf, tag, EVBUFFER_DATA(_buf),
223	    EVBUFFER_LENGTH(_buf));
224}
225
226static int
227decode_int_internal(ev_uint32_t *pnumber, struct evbuffer *evbuf, int dodrain)
228{
229	ev_uint32_t number = 0;
230	ev_uint8_t *data = EVBUFFER_DATA(evbuf);
231	int len = EVBUFFER_LENGTH(evbuf);
232	int nibbles = 0;
233
234	if (!len)
235		return (-1);
236
237	nibbles = ((data[0] & 0xf0) >> 4) + 1;
238	if (nibbles > 8 || (nibbles >> 1) + 1 > len)
239		return (-1);
240	len = (nibbles >> 1) + 1;
241
242	while (nibbles > 0) {
243		number <<= 4;
244		if (nibbles & 0x1)
245			number |= data[nibbles >> 1] & 0x0f;
246		else
247			number |= (data[nibbles >> 1] & 0xf0) >> 4;
248		nibbles--;
249	}
250
251	if (dodrain)
252		evbuffer_drain(evbuf, len);
253
254	*pnumber = number;
255
256	return (len);
257}
258
259int
260evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf)
261{
262	return (decode_int_internal(pnumber, evbuf, 1) == -1 ? -1 : 0);
263}
264
265int
266evtag_peek(struct evbuffer *evbuf, ev_uint32_t *ptag)
267{
268	return (decode_tag_internal(ptag, evbuf, 0 /* dodrain */));
269}
270
271int
272evtag_peek_length(struct evbuffer *evbuf, ev_uint32_t *plength)
273{
274	struct evbuffer tmp;
275	int res, len;
276
277	len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */);
278	if (len == -1)
279		return (-1);
280
281	tmp = *evbuf;
282	tmp.buffer += len;
283	tmp.off -= len;
284
285	res = decode_int_internal(plength, &tmp, 0);
286	if (res == -1)
287		return (-1);
288
289	*plength += res + len;
290
291	return (0);
292}
293
294int
295evtag_payload_length(struct evbuffer *evbuf, ev_uint32_t *plength)
296{
297	struct evbuffer tmp;
298	int res, len;
299
300	len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */);
301	if (len == -1)
302		return (-1);
303
304	tmp = *evbuf;
305	tmp.buffer += len;
306	tmp.off -= len;
307
308	res = decode_int_internal(plength, &tmp, 0);
309	if (res == -1)
310		return (-1);
311
312	return (0);
313}
314
315int
316evtag_consume(struct evbuffer *evbuf)
317{
318	ev_uint32_t len;
319	if (decode_tag_internal(NULL, evbuf, 1 /* dodrain */) == -1)
320		return (-1);
321	if (evtag_decode_int(&len, evbuf) == -1)
322		return (-1);
323	evbuffer_drain(evbuf, len);
324
325	return (0);
326}
327
328/* Reads the data type from an event buffer */
329
330int
331evtag_unmarshal(struct evbuffer *src, ev_uint32_t *ptag, struct evbuffer *dst)
332{
333	ev_uint32_t len;
334	ev_uint32_t integer;
335
336	if (decode_tag_internal(ptag, src, 1 /* dodrain */) == -1)
337		return (-1);
338	if (evtag_decode_int(&integer, src) == -1)
339		return (-1);
340	len = integer;
341
342	if (EVBUFFER_LENGTH(src) < len)
343		return (-1);
344
345	if (evbuffer_add(dst, EVBUFFER_DATA(src), len) == -1)
346		return (-1);
347
348	evbuffer_drain(src, len);
349
350	return (len);
351}
352
353/* Marshaling for integers */
354
355int
356evtag_unmarshal_int(struct evbuffer *evbuf, ev_uint32_t need_tag,
357    ev_uint32_t *pinteger)
358{
359	ev_uint32_t tag;
360	ev_uint32_t len;
361	ev_uint32_t integer;
362
363	if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1)
364		return (-1);
365	if (need_tag != tag)
366		return (-1);
367	if (evtag_decode_int(&integer, evbuf) == -1)
368		return (-1);
369	len = integer;
370
371	if (EVBUFFER_LENGTH(evbuf) < len)
372		return (-1);
373
374	evbuffer_drain(_buf, EVBUFFER_LENGTH(_buf));
375	if (evbuffer_add(_buf, EVBUFFER_DATA(evbuf), len) == -1)
376		return (-1);
377
378	evbuffer_drain(evbuf, len);
379
380	return (evtag_decode_int(pinteger, _buf));
381}
382
383/* Unmarshal a fixed length tag */
384
385int
386evtag_unmarshal_fixed(struct evbuffer *src, ev_uint32_t need_tag, void *data,
387    size_t len)
388{
389	ev_uint32_t tag;
390
391	/* Initialize this event buffer so that we can read into it */
392	evbuffer_drain(_buf, EVBUFFER_LENGTH(_buf));
393
394	/* Now unmarshal a tag and check that it matches the tag we want */
395	if (evtag_unmarshal(src, &tag, _buf) == -1 || tag != need_tag)
396		return (-1);
397
398	if (EVBUFFER_LENGTH(_buf) != len)
399		return (-1);
400
401	memcpy(data, EVBUFFER_DATA(_buf), len);
402	return (0);
403}
404
405int
406evtag_unmarshal_string(struct evbuffer *evbuf, ev_uint32_t need_tag,
407    char **pstring)
408{
409	ev_uint32_t tag;
410
411	evbuffer_drain(_buf, EVBUFFER_LENGTH(_buf));
412
413	if (evtag_unmarshal(evbuf, &tag, _buf) == -1 || tag != need_tag)
414		return (-1);
415
416	*pstring = calloc(EVBUFFER_LENGTH(_buf) + 1, 1);
417	if (*pstring == NULL)
418		event_err(1, "%s: calloc", __func__);
419	evbuffer_remove(_buf, *pstring, EVBUFFER_LENGTH(_buf));
420
421	return (0);
422}
423
424int
425evtag_unmarshal_timeval(struct evbuffer *evbuf, ev_uint32_t need_tag,
426    struct timeval *ptv)
427{
428	ev_uint32_t tag;
429	ev_uint32_t integer;
430
431	evbuffer_drain(_buf, EVBUFFER_LENGTH(_buf));
432	if (evtag_unmarshal(evbuf, &tag, _buf) == -1 || tag != need_tag)
433		return (-1);
434
435	if (evtag_decode_int(&integer, _buf) == -1)
436		return (-1);
437	ptv->tv_sec = integer;
438	if (evtag_decode_int(&integer, _buf) == -1)
439		return (-1);
440	ptv->tv_usec = integer;
441
442	return (0);
443}
444