event_tagging.c revision 1.3
1/* $NetBSD: event_tagging.c,v 1.3 2015/01/29 07:26:02 spz Exp $ */ 2/* 3 * Copyright (c) 2003-2009 Niels Provos <provos@citi.umich.edu> 4 * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29#include "event2/event-config.h" 30#include <sys/cdefs.h> 31__RCSID("$NetBSD: event_tagging.c,v 1.3 2015/01/29 07:26:02 spz Exp $"); 32 33#ifdef _EVENT_HAVE_SYS_TYPES_H 34#include <sys/types.h> 35#endif 36#ifdef _EVENT_HAVE_SYS_PARAM_H 37#include <sys/param.h> 38#endif 39 40#ifdef WIN32 41#define WIN32_LEAN_AND_MEAN 42#include <winsock2.h> 43#include <windows.h> 44#undef WIN32_LEAN_AND_MEAN 45#else 46#include <sys/ioctl.h> 47#endif 48 49#include <sys/queue.h> 50#ifdef _EVENT_HAVE_SYS_TIME_H 51#include <sys/time.h> 52#endif 53 54#include <errno.h> 55#include <stdio.h> 56#include <stdlib.h> 57#include <string.h> 58#ifndef WIN32 59#include <syslog.h> 60#endif 61#ifdef _EVENT_HAVE_UNISTD_H 62#include <unistd.h> 63#endif 64#include <limits.h> 65 66#include "event2/event.h" 67#include "event2/tag.h" 68#include "event2/buffer.h" 69#include "log-internal.h" 70#include "mm-internal.h" 71#include "util-internal.h" 72 73/* 74 Here's our wire format: 75 76 Stream = TaggedData* 77 78 TaggedData = Tag Length Data 79 where the integer value of 'Length' is the length of 'data'. 80 81 Tag = HByte* LByte 82 where HByte is a byte with the high bit set, and LByte is a byte 83 with the high bit clear. The integer value of the tag is taken 84 by concatenating the lower 7 bits from all the tags. So for example, 85 the tag 0x66 is encoded as [66], whereas the tag 0x166 is encoded as 86 [82 66] 87 88 Length = Integer 89 90 Integer = NNibbles Nibble* Padding? 91 where NNibbles is a 4-bit value encoding the number of nibbles-1, 92 and each Nibble is 4 bits worth of encoded integer, in big-endian 93 order. If the total encoded integer size is an odd number of nibbles, 94 a final padding nibble with value 0 is appended. 95*/ 96 97int evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf); 98int evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf); 99int evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag); 100int evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf); 101 102void 103evtag_init(void) 104{ 105} 106 107/* 108 * We encode integers by nibbles; the first nibble contains the number 109 * of significant nibbles - 1; this allows us to encode up to 64-bit 110 * integers. This function is byte-order independent. 111 * 112 * @param number a 32-bit unsigned integer to encode 113 * @param data a pointer to where the data should be written. Must 114 * have at least 5 bytes free. 115 * @return the number of bytes written into data. 116 */ 117 118#define ENCODE_INT_INTERNAL(data, number) do { \ 119 int off = 1, nibbles = 0; \ 120 \ 121 memset(data, 0, sizeof(number)+1); \ 122 while (number) { \ 123 if (off & 0x1) \ 124 data[off/2] = (data[off/2] & 0xf0) | (number & 0x0f); \ 125 else \ 126 data[off/2] = (data[off/2] & 0x0f) | \ 127 ((number & 0x0f) << 4); \ 128 number >>= 4; \ 129 off++; \ 130 } \ 131 \ 132 if (off > 2) \ 133 nibbles = off - 2; \ 134 \ 135 /* Off - 1 is the number of encoded nibbles */ \ 136 data[0] = (data[0] & 0x0f) | ((nibbles & 0x0f) << 4); \ 137 \ 138 return ((off + 1) / 2); \ 139} while (/*CONSTCOND*/0) 140 141static inline int 142encode_int_internal(ev_uint8_t *data, ev_uint32_t number) 143{ 144 ENCODE_INT_INTERNAL(data, number); 145} 146 147static inline int 148encode_int64_internal(ev_uint8_t *data, ev_uint64_t number) 149{ 150 ENCODE_INT_INTERNAL(data, number); 151} 152 153void 154evtag_encode_int(struct evbuffer *evbuf, ev_uint32_t number) 155{ 156 ev_uint8_t data[5]; 157 int len = encode_int_internal(data, number); 158 evbuffer_add(evbuf, data, len); 159} 160 161void 162evtag_encode_int64(struct evbuffer *evbuf, ev_uint64_t number) 163{ 164 ev_uint8_t data[9]; 165 int len = encode_int64_internal(data, number); 166 evbuffer_add(evbuf, data, len); 167} 168 169/* 170 * Support variable length encoding of tags; we use the high bit in each 171 * octet as a continuation signal. 172 */ 173 174int 175evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag) 176{ 177 int bytes = 0; 178 ev_uint8_t data[5]; 179 180 memset(data, 0, sizeof(data)); 181 do { 182 ev_uint8_t lower = tag & 0x7f; 183 tag >>= 7; 184 185 if (tag) 186 lower |= 0x80; 187 188 data[bytes++] = lower; 189 } while (tag); 190 191 if (evbuf != NULL) 192 evbuffer_add(evbuf, data, bytes); 193 194 return (bytes); 195} 196 197static int 198decode_tag_internal(ev_uint32_t *ptag, struct evbuffer *evbuf, int dodrain) 199{ 200 ev_uint32_t number = 0; 201 size_t len = evbuffer_get_length(evbuf); 202 ev_uint8_t *data; 203 size_t count = 0; 204 int shift = 0, done = 0; 205 206 /* 207 * the encoding of a number is at most one byte more than its 208 * storage size. however, it may also be much smaller. 209 */ 210 data = evbuffer_pullup( 211 evbuf, len < sizeof(number) + 1 ? len : sizeof(number) + 1); 212 if (!data) 213 return (-1); 214 215 while (count++ < len) { 216 ev_uint8_t lower = *data++; 217 number |= (lower & 0x7f) << shift; 218 shift += 7; 219 220 if (!(lower & 0x80)) { 221 done = 1; 222 break; 223 } 224 } 225 226 if (!done) 227 return (-1); 228 229 if (dodrain) 230 evbuffer_drain(evbuf, count); 231 232 if (ptag != NULL) 233 *ptag = number; 234 235 return count > INT_MAX ? INT_MAX : (int)(count); 236} 237 238int 239evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf) 240{ 241 return (decode_tag_internal(ptag, evbuf, 1 /* dodrain */)); 242} 243 244/* 245 * Marshal a data type, the general format is as follows: 246 * 247 * tag number: one byte; length: var bytes; payload: var bytes 248 */ 249 250void 251evtag_marshal(struct evbuffer *evbuf, ev_uint32_t tag, 252 const void *data, ev_uint32_t len) 253{ 254 evtag_encode_tag(evbuf, tag); 255 evtag_encode_int(evbuf, len); 256 evbuffer_add(evbuf, __UNCONST(data), len); 257} 258 259void 260evtag_marshal_buffer(struct evbuffer *evbuf, ev_uint32_t tag, 261 struct evbuffer *data) 262{ 263 evtag_encode_tag(evbuf, tag); 264 /* XXX support more than UINT32_MAX data */ 265 evtag_encode_int(evbuf, (ev_uint32_t)evbuffer_get_length(data)); 266 evbuffer_add_buffer(evbuf, data); 267} 268 269/* Marshaling for integers */ 270void 271evtag_marshal_int(struct evbuffer *evbuf, ev_uint32_t tag, ev_uint32_t integer) 272{ 273 ev_uint8_t data[5]; 274 int len = encode_int_internal(data, integer); 275 276 evtag_encode_tag(evbuf, tag); 277 evtag_encode_int(evbuf, len); 278 evbuffer_add(evbuf, data, len); 279} 280 281void 282evtag_marshal_int64(struct evbuffer *evbuf, ev_uint32_t tag, 283 ev_uint64_t integer) 284{ 285 ev_uint8_t data[9]; 286 int len = encode_int64_internal(data, integer); 287 288 evtag_encode_tag(evbuf, tag); 289 evtag_encode_int(evbuf, len); 290 evbuffer_add(evbuf, data, len); 291} 292 293void 294evtag_marshal_string(struct evbuffer *buf, ev_uint32_t tag, const char *string) 295{ 296 /* TODO support strings longer than UINT32_MAX ? */ 297 evtag_marshal(buf, tag, string, (ev_uint32_t)strlen(string)); 298} 299 300void 301evtag_marshal_timeval(struct evbuffer *evbuf, ev_uint32_t tag, struct timeval *tv) 302{ 303 ev_uint8_t data[10]; 304 int len = encode_int_internal(data, tv->tv_sec); 305 len += encode_int_internal(data + len, tv->tv_usec); 306 evtag_marshal(evbuf, tag, data, len); 307} 308 309#define DECODE_INT_INTERNAL(number, maxnibbles, pnumber, evbuf, offset) \ 310do { \ 311 ev_uint8_t *data; \ 312 ev_ssize_t len = evbuffer_get_length(evbuf) - offset; \ 313 int nibbles = 0; \ 314 \ 315 if (len <= 0) \ 316 return (-1); \ 317 \ 318 /* XXX(niels): faster? */ \ 319 data = evbuffer_pullup(evbuf, offset + 1) + offset; \ 320 if (!data) \ 321 return (-1); \ 322 \ 323 nibbles = ((data[0] & 0xf0) >> 4) + 1; \ 324 if (nibbles > maxnibbles || (nibbles >> 1) + 1 > len) \ 325 return (-1); \ 326 len = (nibbles >> 1) + 1; \ 327 \ 328 data = evbuffer_pullup(evbuf, offset + len) + offset; \ 329 if (!data) \ 330 return (-1); \ 331 \ 332 while (nibbles > 0) { \ 333 number <<= 4; \ 334 if (nibbles & 0x1) \ 335 number |= data[nibbles >> 1] & 0x0f; \ 336 else \ 337 number |= (data[nibbles >> 1] & 0xf0) >> 4; \ 338 nibbles--; \ 339 } \ 340 \ 341 *pnumber = number; \ 342 \ 343 return (int)(len); \ 344} while (/*CONSTCOND*/0) 345 346/* Internal: decode an integer from an evbuffer, without draining it. 347 * Only integers up to 32-bits are supported. 348 * 349 * @param evbuf the buffer to read from 350 * @param offset an index into the buffer at which we should start reading. 351 * @param pnumber a pointer to receive the integer. 352 * @return The length of the number as encoded, or -1 on error. 353 */ 354 355static int 356decode_int_internal(ev_uint32_t *pnumber, struct evbuffer *evbuf, int offset) 357{ 358 ev_uint32_t number = 0; 359 DECODE_INT_INTERNAL(number, 8, pnumber, evbuf, offset); 360} 361 362static int 363decode_int64_internal(ev_uint64_t *pnumber, struct evbuffer *evbuf, int offset) 364{ 365 ev_uint64_t number = 0; 366 DECODE_INT_INTERNAL(number, 16, pnumber, evbuf, offset); 367} 368 369int 370evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf) 371{ 372 int res = decode_int_internal(pnumber, evbuf, 0); 373 if (res != -1) 374 evbuffer_drain(evbuf, res); 375 376 return (res == -1 ? -1 : 0); 377} 378 379int 380evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf) 381{ 382 int res = decode_int64_internal(pnumber, evbuf, 0); 383 if (res != -1) 384 evbuffer_drain(evbuf, res); 385 386 return (res == -1 ? -1 : 0); 387} 388 389int 390evtag_peek(struct evbuffer *evbuf, ev_uint32_t *ptag) 391{ 392 return (decode_tag_internal(ptag, evbuf, 0 /* dodrain */)); 393} 394 395int 396evtag_peek_length(struct evbuffer *evbuf, ev_uint32_t *plength) 397{ 398 int res, len; 399 400 len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */); 401 if (len == -1) 402 return (-1); 403 404 res = decode_int_internal(plength, evbuf, len); 405 if (res == -1) 406 return (-1); 407 408 *plength += res + len; 409 410 return (0); 411} 412 413int 414evtag_payload_length(struct evbuffer *evbuf, ev_uint32_t *plength) 415{ 416 int res, len; 417 418 len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */); 419 if (len == -1) 420 return (-1); 421 422 res = decode_int_internal(plength, evbuf, len); 423 if (res == -1) 424 return (-1); 425 426 return (0); 427} 428 429/* just unmarshals the header and returns the length of the remaining data */ 430 431int 432evtag_unmarshal_header(struct evbuffer *evbuf, ev_uint32_t *ptag) 433{ 434 ev_uint32_t len; 435 436 if (decode_tag_internal(ptag, evbuf, 1 /* dodrain */) == -1) 437 return (-1); 438 if (evtag_decode_int(&len, evbuf) == -1) 439 return (-1); 440 441 if (evbuffer_get_length(evbuf) < len) 442 return (-1); 443 444 return (len); 445} 446 447int 448evtag_consume(struct evbuffer *evbuf) 449{ 450 int len; 451 if ((len = evtag_unmarshal_header(evbuf, NULL)) == -1) 452 return (-1); 453 evbuffer_drain(evbuf, len); 454 455 return (0); 456} 457 458/* Reads the data type from an event buffer */ 459 460int 461evtag_unmarshal(struct evbuffer *src, ev_uint32_t *ptag, struct evbuffer *dst) 462{ 463 int len; 464 465 if ((len = evtag_unmarshal_header(src, ptag)) == -1) 466 return (-1); 467 468 if (evbuffer_add(dst, evbuffer_pullup(src, len), len) == -1) 469 return (-1); 470 471 evbuffer_drain(src, len); 472 473 return (len); 474} 475 476/* Marshaling for integers */ 477 478int 479evtag_unmarshal_int(struct evbuffer *evbuf, ev_uint32_t need_tag, 480 ev_uint32_t *pinteger) 481{ 482 ev_uint32_t tag; 483 ev_uint32_t len; 484 int result; 485 486 if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1) 487 return (-1); 488 if (need_tag != tag) 489 return (-1); 490 if (evtag_decode_int(&len, evbuf) == -1) 491 return (-1); 492 493 if (evbuffer_get_length(evbuf) < len) 494 return (-1); 495 496 result = decode_int_internal(pinteger, evbuf, 0); 497 evbuffer_drain(evbuf, len); 498 if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/ 499 return (-1); 500 else 501 return result; 502} 503 504int 505evtag_unmarshal_int64(struct evbuffer *evbuf, ev_uint32_t need_tag, 506 ev_uint64_t *pinteger) 507{ 508 ev_uint32_t tag; 509 ev_uint32_t len; 510 int result; 511 512 if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1) 513 return (-1); 514 if (need_tag != tag) 515 return (-1); 516 if (evtag_decode_int(&len, evbuf) == -1) 517 return (-1); 518 519 if (evbuffer_get_length(evbuf) < len) 520 return (-1); 521 522 result = decode_int64_internal(pinteger, evbuf, 0); 523 evbuffer_drain(evbuf, len); 524 if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/ 525 return (-1); 526 else 527 return result; 528} 529 530/* Unmarshal a fixed length tag */ 531 532int 533evtag_unmarshal_fixed(struct evbuffer *src, ev_uint32_t need_tag, void *data, 534 size_t len) 535{ 536 ev_uint32_t tag; 537 int tag_len; 538 539 /* Now unmarshal a tag and check that it matches the tag we want */ 540 if ((tag_len = evtag_unmarshal_header(src, &tag)) < 0 || 541 tag != need_tag) 542 return (-1); 543 544 if ((size_t)tag_len != len) 545 return (-1); 546 547 evbuffer_remove(src, data, len); 548 return (0); 549} 550 551int 552evtag_unmarshal_string(struct evbuffer *evbuf, ev_uint32_t need_tag, 553 char **pstring) 554{ 555 ev_uint32_t tag; 556 int tag_len; 557 558 if ((tag_len = evtag_unmarshal_header(evbuf, &tag)) == -1 || 559 tag != need_tag) 560 return (-1); 561 562 *pstring = mm_malloc(tag_len + 1); 563 if (*pstring == NULL) { 564 event_warn("%s: malloc", __func__); 565 return -1; 566 } 567 evbuffer_remove(evbuf, *pstring, tag_len); 568 (*pstring)[tag_len] = '\0'; 569 570 return (0); 571} 572 573int 574evtag_unmarshal_timeval(struct evbuffer *evbuf, ev_uint32_t need_tag, 575 struct timeval *ptv) 576{ 577 ev_uint32_t tag; 578 ev_uint32_t integer; 579 int len, offset, offset2; 580 int result = -1; 581 582 if ((len = evtag_unmarshal_header(evbuf, &tag)) == -1) 583 return (-1); 584 if (tag != need_tag) 585 goto done; 586 if ((offset = decode_int_internal(&integer, evbuf, 0)) == -1) 587 goto done; 588 ptv->tv_sec = integer; 589 if ((offset2 = decode_int_internal(&integer, evbuf, offset)) == -1) 590 goto done; 591 ptv->tv_usec = integer; 592 if (offset + offset2 > len) /* XXX Should this be != instead of > ? */ 593 goto done; 594 595 result = 0; 596 done: 597 evbuffer_drain(evbuf, len); 598 return result; 599} 600