event_tagging.c revision 1.5
1/* $NetBSD: event_tagging.c,v 1.5 2021/04/07 03:36:48 christos Exp $ */ 2 3/* 4 * Copyright (c) 2003-2009 Niels Provos <provos@citi.umich.edu> 5 * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30#include "event2/event-config.h" 31#include <sys/cdefs.h> 32__RCSID("$NetBSD: event_tagging.c,v 1.5 2021/04/07 03:36:48 christos Exp $"); 33#include "evconfig-private.h" 34 35#ifdef EVENT__HAVE_SYS_TYPES_H 36#include <sys/types.h> 37#endif 38#ifdef EVENT__HAVE_SYS_PARAM_H 39#include <sys/param.h> 40#endif 41 42#ifdef _WIN32 43#define WIN32_LEAN_AND_MEAN 44#include <winsock2.h> 45#include <windows.h> 46#undef WIN32_LEAN_AND_MEAN 47#endif 48 49#ifdef EVENT__HAVE_SYS_IOCTL_H 50#include <sys/ioctl.h> 51#endif 52#include <sys/queue.h> 53#ifdef EVENT__HAVE_SYS_TIME_H 54#include <sys/time.h> 55#endif 56 57#include <errno.h> 58#include <stdio.h> 59#include <stdlib.h> 60#include <string.h> 61#ifndef _WIN32 62#include <syslog.h> 63#endif 64#ifdef EVENT__HAVE_UNISTD_H 65#include <unistd.h> 66#endif 67#include <limits.h> 68 69#include "event2/event.h" 70#include "event2/tag.h" 71#include "event2/buffer.h" 72#include "log-internal.h" 73#include "mm-internal.h" 74#include "util-internal.h" 75 76/* 77 Here's our wire format: 78 79 Stream = TaggedData* 80 81 TaggedData = Tag Length Data 82 where the integer value of 'Length' is the length of 'data'. 83 84 Tag = HByte* LByte 85 where HByte is a byte with the high bit set, and LByte is a byte 86 with the high bit clear. The integer value of the tag is taken 87 by concatenating the lower 7 bits from all the tags. So for example, 88 the tag 0x66 is encoded as [66], whereas the tag 0x166 is encoded as 89 [82 66] 90 91 Length = Integer 92 93 Integer = NNibbles Nibble* Padding? 94 where NNibbles is a 4-bit value encoding the number of nibbles-1, 95 and each Nibble is 4 bits worth of encoded integer, in big-endian 96 order. If the total encoded integer size is an odd number of nibbles, 97 a final padding nibble with value 0 is appended. 98*/ 99 100EVENT2_EXPORT_SYMBOL 101int evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf); 102EVENT2_EXPORT_SYMBOL 103int evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf); 104EVENT2_EXPORT_SYMBOL 105int evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag); 106EVENT2_EXPORT_SYMBOL 107int evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf); 108 109void 110evtag_init(void) 111{ 112} 113 114/* 115 * We encode integers by nibbles; the first nibble contains the number 116 * of significant nibbles - 1; this allows us to encode up to 64-bit 117 * integers. This function is byte-order independent. 118 * 119 * @param number a 32-bit unsigned integer to encode 120 * @param data a pointer to where the data should be written. Must 121 * have at least 5 bytes free. 122 * @return the number of bytes written into data. 123 */ 124 125#define ENCODE_INT_INTERNAL(data, number) do { \ 126 int off = 1, nibbles = 0; \ 127 \ 128 memset(data, 0, sizeof(number)+1); \ 129 while (number) { \ 130 if (off & 0x1) \ 131 data[off/2] = (data[off/2] & 0xf0) | (number & 0x0f); \ 132 else \ 133 data[off/2] = (data[off/2] & 0x0f) | \ 134 ((number & 0x0f) << 4); \ 135 number >>= 4; \ 136 off++; \ 137 } \ 138 \ 139 if (off > 2) \ 140 nibbles = off - 2; \ 141 \ 142 /* Off - 1 is the number of encoded nibbles */ \ 143 data[0] = (data[0] & 0x0f) | ((nibbles & 0x0f) << 4); \ 144 \ 145 return ((off + 1) / 2); \ 146} while (/*CONSTCOND*/0) 147 148static inline int 149encode_int_internal(ev_uint8_t *data, ev_uint32_t number) 150{ 151 ENCODE_INT_INTERNAL(data, number); 152} 153 154static inline int 155encode_int64_internal(ev_uint8_t *data, ev_uint64_t number) 156{ 157 ENCODE_INT_INTERNAL(data, number); 158} 159 160void 161evtag_encode_int(struct evbuffer *evbuf, ev_uint32_t number) 162{ 163 ev_uint8_t data[5]; 164 int len = encode_int_internal(data, number); 165 evbuffer_add(evbuf, data, len); 166} 167 168void 169evtag_encode_int64(struct evbuffer *evbuf, ev_uint64_t number) 170{ 171 ev_uint8_t data[9]; 172 int len = encode_int64_internal(data, number); 173 evbuffer_add(evbuf, data, len); 174} 175 176/* 177 * Support variable length encoding of tags; we use the high bit in each 178 * octet as a continuation signal. 179 */ 180 181int 182evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag) 183{ 184 int bytes = 0; 185 ev_uint8_t data[5]; 186 187 memset(data, 0, sizeof(data)); 188 do { 189 ev_uint8_t lower = tag & 0x7f; 190 tag >>= 7; 191 192 if (tag) 193 lower |= 0x80; 194 195 data[bytes++] = lower; 196 } while (tag); 197 198 if (evbuf != NULL) 199 evbuffer_add(evbuf, data, bytes); 200 201 return (bytes); 202} 203 204static int 205decode_tag_internal(ev_uint32_t *ptag, struct evbuffer *evbuf, int dodrain) 206{ 207 ev_uint32_t number = 0; 208 size_t len = evbuffer_get_length(evbuf); 209 ev_uint8_t *data; 210 size_t count = 0; 211 int shift = 0, done = 0; 212 213 /* 214 * the encoding of a number is at most one byte more than its 215 * storage size. however, it may also be much smaller. 216 */ 217 data = evbuffer_pullup( 218 evbuf, len < sizeof(number) + 1 ? len : sizeof(number) + 1); 219 if (!data) 220 return (-1); 221 222 while (count++ < len) { 223 ev_uint8_t lower = *data++; 224 if (shift >= 28) { 225 /* Make sure it fits into 32 bits */ 226 if (shift > 28) 227 return (-1); 228 if ((lower & 0x7f) > 15) 229 return (-1); 230 } 231 number |= (lower & (unsigned)0x7f) << shift; 232 shift += 7; 233 234 if (!(lower & 0x80)) { 235 done = 1; 236 break; 237 } 238 } 239 240 if (!done) 241 return (-1); 242 243 if (dodrain) 244 evbuffer_drain(evbuf, count); 245 246 if (ptag != NULL) 247 *ptag = number; 248 249 return count > INT_MAX ? INT_MAX : (int)(count); 250} 251 252int 253evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf) 254{ 255 return (decode_tag_internal(ptag, evbuf, 1 /* dodrain */)); 256} 257 258/* 259 * Marshal a data type, the general format is as follows: 260 * 261 * tag number: one byte; length: var bytes; payload: var bytes 262 */ 263 264void 265evtag_marshal(struct evbuffer *evbuf, ev_uint32_t tag, 266 const void *data, ev_uint32_t len) 267{ 268 evtag_encode_tag(evbuf, tag); 269 evtag_encode_int(evbuf, len); 270 evbuffer_add(evbuf, __UNCONST(data), len); 271} 272 273void 274evtag_marshal_buffer(struct evbuffer *evbuf, ev_uint32_t tag, 275 struct evbuffer *data) 276{ 277 evtag_encode_tag(evbuf, tag); 278 /* XXX support more than UINT32_MAX data */ 279 evtag_encode_int(evbuf, (ev_uint32_t)evbuffer_get_length(data)); 280 evbuffer_add_buffer(evbuf, data); 281} 282 283/* Marshaling for integers */ 284void 285evtag_marshal_int(struct evbuffer *evbuf, ev_uint32_t tag, ev_uint32_t integer) 286{ 287 ev_uint8_t data[5]; 288 int len = encode_int_internal(data, integer); 289 290 evtag_encode_tag(evbuf, tag); 291 evtag_encode_int(evbuf, len); 292 evbuffer_add(evbuf, data, len); 293} 294 295void 296evtag_marshal_int64(struct evbuffer *evbuf, ev_uint32_t tag, 297 ev_uint64_t integer) 298{ 299 ev_uint8_t data[9]; 300 int len = encode_int64_internal(data, integer); 301 302 evtag_encode_tag(evbuf, tag); 303 evtag_encode_int(evbuf, len); 304 evbuffer_add(evbuf, data, len); 305} 306 307void 308evtag_marshal_string(struct evbuffer *buf, ev_uint32_t tag, const char *string) 309{ 310 /* TODO support strings longer than UINT32_MAX ? */ 311 evtag_marshal(buf, tag, string, (ev_uint32_t)strlen(string)); 312} 313 314void 315evtag_marshal_timeval(struct evbuffer *evbuf, ev_uint32_t tag, struct timeval *tv) 316{ 317 ev_uint8_t data[10]; 318 int len = encode_int_internal(data, tv->tv_sec); 319 len += encode_int_internal(data + len, tv->tv_usec); 320 evtag_marshal(evbuf, tag, data, len); 321} 322 323#define DECODE_INT_INTERNAL(number, maxnibbles, pnumber, evbuf, offset) \ 324do { \ 325 ev_uint8_t *data; \ 326 ev_ssize_t len = evbuffer_get_length(evbuf) - offset; \ 327 int nibbles = 0; \ 328 \ 329 if (len <= 0) \ 330 return (-1); \ 331 \ 332 /* XXX(niels): faster? */ \ 333 data = evbuffer_pullup(evbuf, offset + 1) + offset; \ 334 if (!data) \ 335 return (-1); \ 336 \ 337 nibbles = ((data[0] & 0xf0) >> 4) + 1; \ 338 if (nibbles > maxnibbles || (nibbles >> 1) + 1 > len) \ 339 return (-1); \ 340 len = (nibbles >> 1) + 1; \ 341 \ 342 data = evbuffer_pullup(evbuf, offset + len) + offset; \ 343 if (!data) \ 344 return (-1); \ 345 \ 346 while (nibbles > 0) { \ 347 number <<= 4; \ 348 if (nibbles & 0x1) \ 349 number |= data[nibbles >> 1] & 0x0f; \ 350 else \ 351 number |= (data[nibbles >> 1] & 0xf0) >> 4; \ 352 nibbles--; \ 353 } \ 354 \ 355 *pnumber = number; \ 356 \ 357 return (int)(len); \ 358} while (/*CONSTCOND*/0) 359 360/* Internal: decode an integer from an evbuffer, without draining it. 361 * Only integers up to 32-bits are supported. 362 * 363 * @param evbuf the buffer to read from 364 * @param offset an index into the buffer at which we should start reading. 365 * @param pnumber a pointer to receive the integer. 366 * @return The length of the number as encoded, or -1 on error. 367 */ 368 369static int 370decode_int_internal(ev_uint32_t *pnumber, struct evbuffer *evbuf, int offset) 371{ 372 ev_uint32_t number = 0; 373 DECODE_INT_INTERNAL(number, 8, pnumber, evbuf, offset); 374} 375 376static int 377decode_int64_internal(ev_uint64_t *pnumber, struct evbuffer *evbuf, int offset) 378{ 379 ev_uint64_t number = 0; 380 DECODE_INT_INTERNAL(number, 16, pnumber, evbuf, offset); 381} 382 383int 384evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf) 385{ 386 int res = decode_int_internal(pnumber, evbuf, 0); 387 if (res != -1) 388 evbuffer_drain(evbuf, res); 389 390 return (res == -1 ? -1 : 0); 391} 392 393int 394evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf) 395{ 396 int res = decode_int64_internal(pnumber, evbuf, 0); 397 if (res != -1) 398 evbuffer_drain(evbuf, res); 399 400 return (res == -1 ? -1 : 0); 401} 402 403int 404evtag_peek(struct evbuffer *evbuf, ev_uint32_t *ptag) 405{ 406 return (decode_tag_internal(ptag, evbuf, 0 /* dodrain */)); 407} 408 409int 410evtag_peek_length(struct evbuffer *evbuf, ev_uint32_t *plength) 411{ 412 int res, len; 413 414 len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */); 415 if (len == -1) 416 return (-1); 417 418 res = decode_int_internal(plength, evbuf, len); 419 if (res == -1) 420 return (-1); 421 422 *plength += res + len; 423 424 return (0); 425} 426 427int 428evtag_payload_length(struct evbuffer *evbuf, ev_uint32_t *plength) 429{ 430 int res, len; 431 432 len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */); 433 if (len == -1) 434 return (-1); 435 436 res = decode_int_internal(plength, evbuf, len); 437 if (res == -1) 438 return (-1); 439 440 return (0); 441} 442 443/* just unmarshals the header and returns the length of the remaining data */ 444 445int 446evtag_unmarshal_header(struct evbuffer *evbuf, ev_uint32_t *ptag) 447{ 448 ev_uint32_t len; 449 450 if (decode_tag_internal(ptag, evbuf, 1 /* dodrain */) == -1) 451 return (-1); 452 if (evtag_decode_int(&len, evbuf) == -1) 453 return (-1); 454 455 if (evbuffer_get_length(evbuf) < len) 456 return (-1); 457 458 return (len); 459} 460 461int 462evtag_consume(struct evbuffer *evbuf) 463{ 464 int len; 465 if ((len = evtag_unmarshal_header(evbuf, NULL)) == -1) 466 return (-1); 467 evbuffer_drain(evbuf, len); 468 469 return (0); 470} 471 472/* Reads the data type from an event buffer */ 473 474int 475evtag_unmarshal(struct evbuffer *src, ev_uint32_t *ptag, struct evbuffer *dst) 476{ 477 int len; 478 479 if ((len = evtag_unmarshal_header(src, ptag)) == -1) 480 return (-1); 481 482 if (evbuffer_add(dst, evbuffer_pullup(src, len), len) == -1) 483 return (-1); 484 485 evbuffer_drain(src, len); 486 487 return (len); 488} 489 490/* Marshaling for integers */ 491 492int 493evtag_unmarshal_int(struct evbuffer *evbuf, ev_uint32_t need_tag, 494 ev_uint32_t *pinteger) 495{ 496 ev_uint32_t tag; 497 ev_uint32_t len; 498 int result; 499 500 if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1) 501 return (-1); 502 if (need_tag != tag) 503 return (-1); 504 if (evtag_decode_int(&len, evbuf) == -1) 505 return (-1); 506 507 if (evbuffer_get_length(evbuf) < len) 508 return (-1); 509 510 result = decode_int_internal(pinteger, evbuf, 0); 511 evbuffer_drain(evbuf, len); 512 if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/ 513 return (-1); 514 else 515 return result; 516} 517 518int 519evtag_unmarshal_int64(struct evbuffer *evbuf, ev_uint32_t need_tag, 520 ev_uint64_t *pinteger) 521{ 522 ev_uint32_t tag; 523 ev_uint32_t len; 524 int result; 525 526 if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1) 527 return (-1); 528 if (need_tag != tag) 529 return (-1); 530 if (evtag_decode_int(&len, evbuf) == -1) 531 return (-1); 532 533 if (evbuffer_get_length(evbuf) < len) 534 return (-1); 535 536 result = decode_int64_internal(pinteger, evbuf, 0); 537 evbuffer_drain(evbuf, len); 538 if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/ 539 return (-1); 540 else 541 return result; 542} 543 544/* Unmarshal a fixed length tag */ 545 546int 547evtag_unmarshal_fixed(struct evbuffer *src, ev_uint32_t need_tag, void *data, 548 size_t len) 549{ 550 ev_uint32_t tag; 551 int tag_len; 552 553 /* Now unmarshal a tag and check that it matches the tag we want */ 554 if ((tag_len = evtag_unmarshal_header(src, &tag)) < 0 || 555 tag != need_tag) 556 return (-1); 557 558 if ((size_t)tag_len != len) 559 return (-1); 560 561 evbuffer_remove(src, data, len); 562 return (0); 563} 564 565int 566evtag_unmarshal_string(struct evbuffer *evbuf, ev_uint32_t need_tag, 567 char **pstring) 568{ 569 ev_uint32_t tag; 570 int tag_len; 571 572 if ((tag_len = evtag_unmarshal_header(evbuf, &tag)) == -1 || 573 tag != need_tag) 574 return (-1); 575 576 *pstring = mm_malloc(tag_len + 1); 577 if (*pstring == NULL) { 578 event_warn("%s: malloc", __func__); 579 return -1; 580 } 581 evbuffer_remove(evbuf, *pstring, tag_len); 582 (*pstring)[tag_len] = '\0'; 583 584 return (0); 585} 586 587int 588evtag_unmarshal_timeval(struct evbuffer *evbuf, ev_uint32_t need_tag, 589 struct timeval *ptv) 590{ 591 ev_uint32_t tag; 592 ev_uint32_t integer; 593 int len, offset, offset2; 594 int result = -1; 595 596 if ((len = evtag_unmarshal_header(evbuf, &tag)) == -1) 597 return (-1); 598 if (tag != need_tag) 599 goto done; 600 if ((offset = decode_int_internal(&integer, evbuf, 0)) == -1) 601 goto done; 602 ptv->tv_sec = integer; 603 if ((offset2 = decode_int_internal(&integer, evbuf, offset)) == -1) 604 goto done; 605 ptv->tv_usec = integer; 606 if (offset + offset2 > len) /* XXX Should this be != instead of > ? */ 607 goto done; 608 609 result = 0; 610 done: 611 evbuffer_drain(evbuf, len); 612 return result; 613} 614