1/* 2 * Copyright (c) 2003-2009 Niels Provos <provos@citi.umich.edu> 3 * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson 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#include "event2/event-config.h" 29 30#ifdef _EVENT_HAVE_SYS_TYPES_H 31#include <sys/types.h> 32#endif 33#ifdef _EVENT_HAVE_SYS_PARAM_H 34#include <sys/param.h> 35#endif 36 37#ifdef WIN32 38#define WIN32_LEAN_AND_MEAN 39#include <winsock2.h> 40#include <windows.h> 41#undef WIN32_LEAN_AND_MEAN 42#else 43#include <sys/ioctl.h> 44#endif 45 46#include <sys/queue.h> 47#ifdef _EVENT_HAVE_SYS_TIME_H 48#include <sys/time.h> 49#endif 50 51#include <errno.h> 52#include <stdio.h> 53#include <stdlib.h> 54#include <string.h> 55#ifndef WIN32 56#include <syslog.h> 57#endif 58#ifdef _EVENT_HAVE_UNISTD_H 59#include <unistd.h> 60#endif 61#include <limits.h> 62 63#include "event2/event.h" 64#include "event2/tag.h" 65#include "event2/buffer.h" 66#include "log-internal.h" 67#include "mm-internal.h" 68#include "util-internal.h" 69 70/* 71 Here's our wire format: 72 73 Stream = TaggedData* 74 75 TaggedData = Tag Length Data 76 where the integer value of 'Length' is the length of 'data'. 77 78 Tag = HByte* LByte 79 where HByte is a byte with the high bit set, and LByte is a byte 80 with the high bit clear. The integer value of the tag is taken 81 by concatenating the lower 7 bits from all the tags. So for example, 82 the tag 0x66 is encoded as [66], whereas the tag 0x166 is encoded as 83 [82 66] 84 85 Length = Integer 86 87 Integer = NNibbles Nibble* Padding? 88 where NNibbles is a 4-bit value encoding the number of nibbles-1, 89 and each Nibble is 4 bits worth of encoded integer, in big-endian 90 order. If the total encoded integer size is an odd number of nibbles, 91 a final padding nibble with value 0 is appended. 92*/ 93 94int evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf); 95int evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf); 96int evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag); 97int evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf); 98 99void 100evtag_init(void) 101{ 102} 103 104/* 105 * We encode integers by nibbles; the first nibble contains the number 106 * of significant nibbles - 1; this allows us to encode up to 64-bit 107 * integers. This function is byte-order independent. 108 * 109 * @param number a 32-bit unsigned integer to encode 110 * @param data a pointer to where the data should be written. Must 111 * have at least 5 bytes free. 112 * @return the number of bytes written into data. 113 */ 114 115#define ENCODE_INT_INTERNAL(data, number) do { \ 116 int off = 1, nibbles = 0; \ 117 \ 118 memset(data, 0, sizeof(number)+1); \ 119 while (number) { \ 120 if (off & 0x1) \ 121 data[off/2] = (data[off/2] & 0xf0) | (number & 0x0f); \ 122 else \ 123 data[off/2] = (data[off/2] & 0x0f) | \ 124 ((number & 0x0f) << 4); \ 125 number >>= 4; \ 126 off++; \ 127 } \ 128 \ 129 if (off > 2) \ 130 nibbles = off - 2; \ 131 \ 132 /* Off - 1 is the number of encoded nibbles */ \ 133 data[0] = (data[0] & 0x0f) | ((nibbles & 0x0f) << 4); \ 134 \ 135 return ((off + 1) / 2); \ 136} while (0) 137 138static inline int 139encode_int_internal(ev_uint8_t *data, ev_uint32_t number) 140{ 141 ENCODE_INT_INTERNAL(data, number); 142} 143 144static inline int 145encode_int64_internal(ev_uint8_t *data, ev_uint64_t number) 146{ 147 ENCODE_INT_INTERNAL(data, number); 148} 149 150void 151evtag_encode_int(struct evbuffer *evbuf, ev_uint32_t number) 152{ 153 ev_uint8_t data[5]; 154 int len = encode_int_internal(data, number); 155 evbuffer_add(evbuf, data, len); 156} 157 158void 159evtag_encode_int64(struct evbuffer *evbuf, ev_uint64_t number) 160{ 161 ev_uint8_t data[9]; 162 int len = encode_int64_internal(data, number); 163 evbuffer_add(evbuf, data, len); 164} 165 166/* 167 * Support variable length encoding of tags; we use the high bit in each 168 * octet as a continuation signal. 169 */ 170 171int 172evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag) 173{ 174 int bytes = 0; 175 ev_uint8_t data[5]; 176 177 memset(data, 0, sizeof(data)); 178 do { 179 ev_uint8_t lower = tag & 0x7f; 180 tag >>= 7; 181 182 if (tag) 183 lower |= 0x80; 184 185 data[bytes++] = lower; 186 } while (tag); 187 188 if (evbuf != NULL) 189 evbuffer_add(evbuf, data, bytes); 190 191 return (bytes); 192} 193 194static int 195decode_tag_internal(ev_uint32_t *ptag, struct evbuffer *evbuf, int dodrain) 196{ 197 ev_uint32_t number = 0; 198 size_t len = evbuffer_get_length(evbuf); 199 ev_uint8_t *data; 200 size_t count = 0; 201 int shift = 0, done = 0; 202 203 /* 204 * the encoding of a number is at most one byte more than its 205 * storage size. however, it may also be much smaller. 206 */ 207 data = evbuffer_pullup( 208 evbuf, len < sizeof(number) + 1 ? len : sizeof(number) + 1); 209 210 while (count++ < len) { 211 ev_uint8_t lower = *data++; 212 number |= (lower & 0x7f) << shift; 213 shift += 7; 214 215 if (!(lower & 0x80)) { 216 done = 1; 217 break; 218 } 219 } 220 221 if (!done) 222 return (-1); 223 224 if (dodrain) 225 evbuffer_drain(evbuf, count); 226 227 if (ptag != NULL) 228 *ptag = number; 229 230 return count > INT_MAX ? INT_MAX : (int)(count); 231} 232 233int 234evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf) 235{ 236 return (decode_tag_internal(ptag, evbuf, 1 /* dodrain */)); 237} 238 239/* 240 * Marshal a data type, the general format is as follows: 241 * 242 * tag number: one byte; length: var bytes; payload: var bytes 243 */ 244 245void 246evtag_marshal(struct evbuffer *evbuf, ev_uint32_t tag, 247 const void *data, ev_uint32_t len) 248{ 249 evtag_encode_tag(evbuf, tag); 250 evtag_encode_int(evbuf, len); 251 evbuffer_add(evbuf, (void *)data, len); 252} 253 254void 255evtag_marshal_buffer(struct evbuffer *evbuf, ev_uint32_t tag, 256 struct evbuffer *data) 257{ 258 evtag_encode_tag(evbuf, tag); 259 /* XXX support more than UINT32_MAX data */ 260 evtag_encode_int(evbuf, (ev_uint32_t)evbuffer_get_length(data)); 261 evbuffer_add_buffer(evbuf, data); 262} 263 264/* Marshaling for integers */ 265void 266evtag_marshal_int(struct evbuffer *evbuf, ev_uint32_t tag, ev_uint32_t integer) 267{ 268 ev_uint8_t data[5]; 269 int len = encode_int_internal(data, integer); 270 271 evtag_encode_tag(evbuf, tag); 272 evtag_encode_int(evbuf, len); 273 evbuffer_add(evbuf, data, len); 274} 275 276void 277evtag_marshal_int64(struct evbuffer *evbuf, ev_uint32_t tag, 278 ev_uint64_t integer) 279{ 280 ev_uint8_t data[9]; 281 int len = encode_int64_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_string(struct evbuffer *buf, ev_uint32_t tag, const char *string) 290{ 291 /* TODO support strings longer than UINT32_MAX ? */ 292 evtag_marshal(buf, tag, string, (ev_uint32_t)strlen(string)); 293} 294 295void 296evtag_marshal_timeval(struct evbuffer *evbuf, ev_uint32_t tag, struct timeval *tv) 297{ 298 ev_uint8_t data[10]; 299 int len = encode_int_internal(data, tv->tv_sec); 300 len += encode_int_internal(data + len, tv->tv_usec); 301 evtag_marshal(evbuf, tag, data, len); 302} 303 304#define DECODE_INT_INTERNAL(number, maxnibbles, pnumber, evbuf, offset) \ 305do { \ 306 ev_uint8_t *data; \ 307 ev_ssize_t len = evbuffer_get_length(evbuf) - offset; \ 308 int nibbles = 0; \ 309 \ 310 if (len <= 0) \ 311 return (-1); \ 312 \ 313 /* XXX(niels): faster? */ \ 314 data = evbuffer_pullup(evbuf, offset + 1) + offset; \ 315 \ 316 nibbles = ((data[0] & 0xf0) >> 4) + 1; \ 317 if (nibbles > maxnibbles || (nibbles >> 1) + 1 > len) \ 318 return (-1); \ 319 len = (nibbles >> 1) + 1; \ 320 \ 321 data = evbuffer_pullup(evbuf, offset + len) + offset; \ 322 \ 323 while (nibbles > 0) { \ 324 number <<= 4; \ 325 if (nibbles & 0x1) \ 326 number |= data[nibbles >> 1] & 0x0f; \ 327 else \ 328 number |= (data[nibbles >> 1] & 0xf0) >> 4; \ 329 nibbles--; \ 330 } \ 331 \ 332 *pnumber = number; \ 333 \ 334 return (int)(len); \ 335} while (0) 336 337/* Internal: decode an integer from an evbuffer, without draining it. 338 * Only integers up to 32-bits are supported. 339 * 340 * @param evbuf the buffer to read from 341 * @param offset an index into the buffer at which we should start reading. 342 * @param pnumber a pointer to receive the integer. 343 * @return The length of the number as encoded, or -1 on error. 344 */ 345 346static int 347decode_int_internal(ev_uint32_t *pnumber, struct evbuffer *evbuf, int offset) 348{ 349 ev_uint32_t number = 0; 350 DECODE_INT_INTERNAL(number, 8, pnumber, evbuf, offset); 351} 352 353static int 354decode_int64_internal(ev_uint64_t *pnumber, struct evbuffer *evbuf, int offset) 355{ 356 ev_uint64_t number = 0; 357 DECODE_INT_INTERNAL(number, 16, pnumber, evbuf, offset); 358} 359 360int 361evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf) 362{ 363 int res = decode_int_internal(pnumber, evbuf, 0); 364 if (res != -1) 365 evbuffer_drain(evbuf, res); 366 367 return (res == -1 ? -1 : 0); 368} 369 370int 371evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf) 372{ 373 int res = decode_int64_internal(pnumber, evbuf, 0); 374 if (res != -1) 375 evbuffer_drain(evbuf, res); 376 377 return (res == -1 ? -1 : 0); 378} 379 380int 381evtag_peek(struct evbuffer *evbuf, ev_uint32_t *ptag) 382{ 383 return (decode_tag_internal(ptag, evbuf, 0 /* dodrain */)); 384} 385 386int 387evtag_peek_length(struct evbuffer *evbuf, ev_uint32_t *plength) 388{ 389 int res, len; 390 391 len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */); 392 if (len == -1) 393 return (-1); 394 395 res = decode_int_internal(plength, evbuf, len); 396 if (res == -1) 397 return (-1); 398 399 *plength += res + len; 400 401 return (0); 402} 403 404int 405evtag_payload_length(struct evbuffer *evbuf, ev_uint32_t *plength) 406{ 407 int res, len; 408 409 len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */); 410 if (len == -1) 411 return (-1); 412 413 res = decode_int_internal(plength, evbuf, len); 414 if (res == -1) 415 return (-1); 416 417 return (0); 418} 419 420/* just unmarshals the header and returns the length of the remaining data */ 421 422int 423evtag_unmarshal_header(struct evbuffer *evbuf, ev_uint32_t *ptag) 424{ 425 ev_uint32_t len; 426 427 if (decode_tag_internal(ptag, evbuf, 1 /* dodrain */) == -1) 428 return (-1); 429 if (evtag_decode_int(&len, evbuf) == -1) 430 return (-1); 431 432 if (evbuffer_get_length(evbuf) < len) 433 return (-1); 434 435 return (len); 436} 437 438int 439evtag_consume(struct evbuffer *evbuf) 440{ 441 int len; 442 if ((len = evtag_unmarshal_header(evbuf, NULL)) == -1) 443 return (-1); 444 evbuffer_drain(evbuf, len); 445 446 return (0); 447} 448 449/* Reads the data type from an event buffer */ 450 451int 452evtag_unmarshal(struct evbuffer *src, ev_uint32_t *ptag, struct evbuffer *dst) 453{ 454 int len; 455 456 if ((len = evtag_unmarshal_header(src, ptag)) == -1) 457 return (-1); 458 459 if (evbuffer_add(dst, evbuffer_pullup(src, len), len) == -1) 460 return (-1); 461 462 evbuffer_drain(src, len); 463 464 return (len); 465} 466 467/* Marshaling for integers */ 468 469int 470evtag_unmarshal_int(struct evbuffer *evbuf, ev_uint32_t need_tag, 471 ev_uint32_t *pinteger) 472{ 473 ev_uint32_t tag; 474 ev_uint32_t len; 475 int result; 476 477 if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1) 478 return (-1); 479 if (need_tag != tag) 480 return (-1); 481 if (evtag_decode_int(&len, evbuf) == -1) 482 return (-1); 483 484 if (evbuffer_get_length(evbuf) < len) 485 return (-1); 486 487 result = decode_int_internal(pinteger, evbuf, 0); 488 evbuffer_drain(evbuf, len); 489 if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/ 490 return (-1); 491 else 492 return result; 493} 494 495int 496evtag_unmarshal_int64(struct evbuffer *evbuf, ev_uint32_t need_tag, 497 ev_uint64_t *pinteger) 498{ 499 ev_uint32_t tag; 500 ev_uint32_t len; 501 int result; 502 503 if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1) 504 return (-1); 505 if (need_tag != tag) 506 return (-1); 507 if (evtag_decode_int(&len, evbuf) == -1) 508 return (-1); 509 510 if (evbuffer_get_length(evbuf) < len) 511 return (-1); 512 513 result = decode_int64_internal(pinteger, evbuf, 0); 514 evbuffer_drain(evbuf, len); 515 if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/ 516 return (-1); 517 else 518 return result; 519} 520 521/* Unmarshal a fixed length tag */ 522 523int 524evtag_unmarshal_fixed(struct evbuffer *src, ev_uint32_t need_tag, void *data, 525 size_t len) 526{ 527 ev_uint32_t tag; 528 int tag_len; 529 530 /* Now unmarshal a tag and check that it matches the tag we want */ 531 if ((tag_len = evtag_unmarshal_header(src, &tag)) < 0 || 532 tag != need_tag) 533 return (-1); 534 535 if ((size_t)tag_len != len) 536 return (-1); 537 538 evbuffer_remove(src, data, len); 539 return (0); 540} 541 542int 543evtag_unmarshal_string(struct evbuffer *evbuf, ev_uint32_t need_tag, 544 char **pstring) 545{ 546 ev_uint32_t tag; 547 int tag_len; 548 549 if ((tag_len = evtag_unmarshal_header(evbuf, &tag)) == -1 || 550 tag != need_tag) 551 return (-1); 552 553 *pstring = mm_malloc(tag_len + 1); 554 if (*pstring == NULL) { 555 event_warn("%s: malloc", __func__); 556 return -1; 557 } 558 evbuffer_remove(evbuf, *pstring, tag_len); 559 (*pstring)[tag_len] = '\0'; 560 561 return (0); 562} 563 564int 565evtag_unmarshal_timeval(struct evbuffer *evbuf, ev_uint32_t need_tag, 566 struct timeval *ptv) 567{ 568 ev_uint32_t tag; 569 ev_uint32_t integer; 570 int len, offset, offset2; 571 int result = -1; 572 573 if ((len = evtag_unmarshal_header(evbuf, &tag)) == -1) 574 return (-1); 575 if (tag != need_tag) 576 goto done; 577 if ((offset = decode_int_internal(&integer, evbuf, 0)) == -1) 578 goto done; 579 ptv->tv_sec = integer; 580 if ((offset2 = decode_int_internal(&integer, evbuf, offset)) == -1) 581 goto done; 582 ptv->tv_usec = integer; 583 if (offset + offset2 > len) /* XXX Should this be != instead of > ? */ 584 goto done; 585 586 result = 0; 587 done: 588 evbuffer_drain(evbuf, len); 589 return result; 590} 591