1/* $NetBSD: event_tagging.c,v 1.6 2020/05/25 20:47:33 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 "evconfig-private.h" 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 (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 if (shift >= 28) { 218 /* Make sure it fits into 32 bits */ 219 if (shift > 28) 220 return (-1); 221 if ((lower & 0x7f) > 15) 222 return (-1); 223 } 224 number |= (lower & (unsigned)0x7f) << shift; 225 shift += 7; 226 227 if (!(lower & 0x80)) { 228 done = 1; 229 break; 230 } 231 } 232 233 if (!done) 234 return (-1); 235 236 if (dodrain) 237 evbuffer_drain(evbuf, count); 238 239 if (ptag != NULL) 240 *ptag = number; 241 242 return count > INT_MAX ? INT_MAX : (int)(count); 243} 244 245int 246evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf) 247{ 248 return (decode_tag_internal(ptag, evbuf, 1 /* dodrain */)); 249} 250 251/* 252 * Marshal a data type, the general format is as follows: 253 * 254 * tag number: one byte; length: var bytes; payload: var bytes 255 */ 256 257void 258evtag_marshal(struct evbuffer *evbuf, ev_uint32_t tag, 259 const void *data, ev_uint32_t len) 260{ 261 evtag_encode_tag(evbuf, tag); 262 evtag_encode_int(evbuf, len); 263 evbuffer_add(evbuf, (void *)data, len); 264} 265 266void 267evtag_marshal_buffer(struct evbuffer *evbuf, ev_uint32_t tag, 268 struct evbuffer *data) 269{ 270 evtag_encode_tag(evbuf, tag); 271 /* XXX support more than UINT32_MAX data */ 272 evtag_encode_int(evbuf, (ev_uint32_t)evbuffer_get_length(data)); 273 evbuffer_add_buffer(evbuf, data); 274} 275 276/* Marshaling for integers */ 277void 278evtag_marshal_int(struct evbuffer *evbuf, ev_uint32_t tag, ev_uint32_t integer) 279{ 280 ev_uint8_t data[5]; 281 int len = encode_int_internal(data, integer); 282 283 evtag_encode_tag(evbuf, tag); 284 evtag_encode_int(evbuf, len); 285 evbuffer_add(evbuf, data, len); 286} 287 288void 289evtag_marshal_int64(struct evbuffer *evbuf, ev_uint32_t tag, 290 ev_uint64_t integer) 291{ 292 ev_uint8_t data[9]; 293 int len = encode_int64_internal(data, integer); 294 295 evtag_encode_tag(evbuf, tag); 296 evtag_encode_int(evbuf, len); 297 evbuffer_add(evbuf, data, len); 298} 299 300void 301evtag_marshal_string(struct evbuffer *buf, ev_uint32_t tag, const char *string) 302{ 303 /* TODO support strings longer than UINT32_MAX ? */ 304 evtag_marshal(buf, tag, string, (ev_uint32_t)strlen(string)); 305} 306 307void 308evtag_marshal_timeval(struct evbuffer *evbuf, ev_uint32_t tag, struct timeval *tv) 309{ 310 ev_uint8_t data[10]; 311 int len = encode_int_internal(data, tv->tv_sec); 312 len += encode_int_internal(data + len, tv->tv_usec); 313 evtag_marshal(evbuf, tag, data, len); 314} 315 316#define DECODE_INT_INTERNAL(number, maxnibbles, pnumber, evbuf, offset) \ 317do { \ 318 ev_uint8_t *data; \ 319 ev_ssize_t len = evbuffer_get_length(evbuf) - offset; \ 320 int nibbles = 0; \ 321 \ 322 if (len <= 0) \ 323 return (-1); \ 324 \ 325 /* XXX(niels): faster? */ \ 326 data = evbuffer_pullup(evbuf, offset + 1) + offset; \ 327 if (!data) \ 328 return (-1); \ 329 \ 330 nibbles = ((data[0] & 0xf0) >> 4) + 1; \ 331 if (nibbles > maxnibbles || (nibbles >> 1) + 1 > len) \ 332 return (-1); \ 333 len = (nibbles >> 1) + 1; \ 334 \ 335 data = evbuffer_pullup(evbuf, offset + len) + offset; \ 336 if (!data) \ 337 return (-1); \ 338 \ 339 while (nibbles > 0) { \ 340 number <<= 4; \ 341 if (nibbles & 0x1) \ 342 number |= data[nibbles >> 1] & 0x0f; \ 343 else \ 344 number |= (data[nibbles >> 1] & 0xf0) >> 4; \ 345 nibbles--; \ 346 } \ 347 \ 348 *pnumber = number; \ 349 \ 350 return (int)(len); \ 351} while (0) 352 353/* Internal: decode an integer from an evbuffer, without draining it. 354 * Only integers up to 32-bits are supported. 355 * 356 * @param evbuf the buffer to read from 357 * @param offset an index into the buffer at which we should start reading. 358 * @param pnumber a pointer to receive the integer. 359 * @return The length of the number as encoded, or -1 on error. 360 */ 361 362static int 363decode_int_internal(ev_uint32_t *pnumber, struct evbuffer *evbuf, int offset) 364{ 365 ev_uint32_t number = 0; 366 DECODE_INT_INTERNAL(number, 8, pnumber, evbuf, offset); 367} 368 369static int 370decode_int64_internal(ev_uint64_t *pnumber, struct evbuffer *evbuf, int offset) 371{ 372 ev_uint64_t number = 0; 373 DECODE_INT_INTERNAL(number, 16, pnumber, evbuf, offset); 374} 375 376int 377evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf) 378{ 379 int res = decode_int_internal(pnumber, evbuf, 0); 380 if (res != -1) 381 evbuffer_drain(evbuf, res); 382 383 return (res == -1 ? -1 : 0); 384} 385 386int 387evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf) 388{ 389 int res = decode_int64_internal(pnumber, evbuf, 0); 390 if (res != -1) 391 evbuffer_drain(evbuf, res); 392 393 return (res == -1 ? -1 : 0); 394} 395 396int 397evtag_peek(struct evbuffer *evbuf, ev_uint32_t *ptag) 398{ 399 return (decode_tag_internal(ptag, evbuf, 0 /* dodrain */)); 400} 401 402int 403evtag_peek_length(struct evbuffer *evbuf, ev_uint32_t *plength) 404{ 405 int res, len; 406 407 len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */); 408 if (len == -1) 409 return (-1); 410 411 res = decode_int_internal(plength, evbuf, len); 412 if (res == -1) 413 return (-1); 414 415 *plength += res + len; 416 417 return (0); 418} 419 420int 421evtag_payload_length(struct evbuffer *evbuf, ev_uint32_t *plength) 422{ 423 int res, len; 424 425 len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */); 426 if (len == -1) 427 return (-1); 428 429 res = decode_int_internal(plength, evbuf, len); 430 if (res == -1) 431 return (-1); 432 433 return (0); 434} 435 436/* just unmarshals the header and returns the length of the remaining data */ 437 438int 439evtag_unmarshal_header(struct evbuffer *evbuf, ev_uint32_t *ptag) 440{ 441 ev_uint32_t len; 442 443 if (decode_tag_internal(ptag, evbuf, 1 /* dodrain */) == -1) 444 return (-1); 445 if (evtag_decode_int(&len, evbuf) == -1) 446 return (-1); 447 448 if (evbuffer_get_length(evbuf) < len) 449 return (-1); 450 451 return (len); 452} 453 454int 455evtag_consume(struct evbuffer *evbuf) 456{ 457 int len; 458 if ((len = evtag_unmarshal_header(evbuf, NULL)) == -1) 459 return (-1); 460 evbuffer_drain(evbuf, len); 461 462 return (0); 463} 464 465/* Reads the data type from an event buffer */ 466 467int 468evtag_unmarshal(struct evbuffer *src, ev_uint32_t *ptag, struct evbuffer *dst) 469{ 470 int len; 471 472 if ((len = evtag_unmarshal_header(src, ptag)) == -1) 473 return (-1); 474 475 if (evbuffer_add(dst, evbuffer_pullup(src, len), len) == -1) 476 return (-1); 477 478 evbuffer_drain(src, len); 479 480 return (len); 481} 482 483/* Marshaling for integers */ 484 485int 486evtag_unmarshal_int(struct evbuffer *evbuf, ev_uint32_t need_tag, 487 ev_uint32_t *pinteger) 488{ 489 ev_uint32_t tag; 490 ev_uint32_t len; 491 int result; 492 493 if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1) 494 return (-1); 495 if (need_tag != tag) 496 return (-1); 497 if (evtag_decode_int(&len, evbuf) == -1) 498 return (-1); 499 500 if (evbuffer_get_length(evbuf) < len) 501 return (-1); 502 503 result = decode_int_internal(pinteger, evbuf, 0); 504 evbuffer_drain(evbuf, len); 505 if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/ 506 return (-1); 507 else 508 return result; 509} 510 511int 512evtag_unmarshal_int64(struct evbuffer *evbuf, ev_uint32_t need_tag, 513 ev_uint64_t *pinteger) 514{ 515 ev_uint32_t tag; 516 ev_uint32_t len; 517 int result; 518 519 if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1) 520 return (-1); 521 if (need_tag != tag) 522 return (-1); 523 if (evtag_decode_int(&len, evbuf) == -1) 524 return (-1); 525 526 if (evbuffer_get_length(evbuf) < len) 527 return (-1); 528 529 result = decode_int64_internal(pinteger, evbuf, 0); 530 evbuffer_drain(evbuf, len); 531 if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/ 532 return (-1); 533 else 534 return result; 535} 536 537/* Unmarshal a fixed length tag */ 538 539int 540evtag_unmarshal_fixed(struct evbuffer *src, ev_uint32_t need_tag, void *data, 541 size_t len) 542{ 543 ev_uint32_t tag; 544 int tag_len; 545 546 /* Now unmarshal a tag and check that it matches the tag we want */ 547 if ((tag_len = evtag_unmarshal_header(src, &tag)) < 0 || 548 tag != need_tag) 549 return (-1); 550 551 if ((size_t)tag_len != len) 552 return (-1); 553 554 evbuffer_remove(src, data, len); 555 return (0); 556} 557 558int 559evtag_unmarshal_string(struct evbuffer *evbuf, ev_uint32_t need_tag, 560 char **pstring) 561{ 562 ev_uint32_t tag; 563 int tag_len; 564 565 if ((tag_len = evtag_unmarshal_header(evbuf, &tag)) == -1 || 566 tag != need_tag) 567 return (-1); 568 569 *pstring = mm_malloc(tag_len + 1); 570 if (*pstring == NULL) { 571 event_warn("%s: malloc", __func__); 572 return -1; 573 } 574 evbuffer_remove(evbuf, *pstring, tag_len); 575 (*pstring)[tag_len] = '\0'; 576 577 return (0); 578} 579 580int 581evtag_unmarshal_timeval(struct evbuffer *evbuf, ev_uint32_t need_tag, 582 struct timeval *ptv) 583{ 584 ev_uint32_t tag; 585 ev_uint32_t integer; 586 int len, offset, offset2; 587 int result = -1; 588 589 if ((len = evtag_unmarshal_header(evbuf, &tag)) == -1) 590 return (-1); 591 if (tag != need_tag) 592 goto done; 593 if ((offset = decode_int_internal(&integer, evbuf, 0)) == -1) 594 goto done; 595 ptv->tv_sec = integer; 596 if ((offset2 = decode_int_internal(&integer, evbuf, offset)) == -1) 597 goto done; 598 ptv->tv_usec = integer; 599 if (offset + offset2 > len) /* XXX Should this be != instead of > ? */ 600 goto done; 601 602 result = 0; 603 done: 604 evbuffer_drain(evbuf, len); 605 return result; 606} 607