1/* $Id$ */ 2 3/*** 4 This file is part of avahi. 5 6 avahi is free software; you can redistribute it and/or modify it 7 under the terms of the GNU Lesser General Public License as 8 published by the Free Software Foundation; either version 2.1 of the 9 License, or (at your option) any later version. 10 11 avahi is distributed in the hope that it will be useful, but WITHOUT 12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General 14 Public License for more details. 15 16 You should have received a copy of the GNU Lesser General Public 17 License along with avahi; if not, write to the Free Software 18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 19 USA. 20***/ 21 22#ifdef HAVE_CONFIG_H 23#include <config.h> 24#endif 25 26#include <stdlib.h> 27#include <string.h> 28#include <stdio.h> 29#include <assert.h> 30 31#include <sys/types.h> 32#include <netinet/in.h> 33 34#include <avahi-common/defs.h> 35#include <avahi-common/domain.h> 36#include <avahi-common/malloc.h> 37 38#include "dns.h" 39#include "log.h" 40 41AvahiDnsPacket* avahi_dns_packet_new(unsigned mtu) { 42 AvahiDnsPacket *p; 43 size_t max_size; 44 45 if (mtu <= 0) 46 max_size = AVAHI_DNS_PACKET_SIZE_MAX; 47 else if (mtu >= AVAHI_DNS_PACKET_EXTRA_SIZE) 48 max_size = mtu - AVAHI_DNS_PACKET_EXTRA_SIZE; 49 else 50 max_size = 0; 51 52 if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE) 53 max_size = AVAHI_DNS_PACKET_HEADER_SIZE; 54 55 if (!(p = avahi_malloc(sizeof(AvahiDnsPacket) + max_size))) 56 return p; 57 58 p->size = p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE; 59 p->max_size = max_size; 60 p->name_table = NULL; 61 p->data = NULL; 62 63 memset(AVAHI_DNS_PACKET_DATA(p), 0, p->size); 64 return p; 65} 66 67AvahiDnsPacket* avahi_dns_packet_new_query(unsigned mtu) { 68 AvahiDnsPacket *p; 69 70 if (!(p = avahi_dns_packet_new(mtu))) 71 return NULL; 72 73 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0)); 74 return p; 75} 76 77AvahiDnsPacket* avahi_dns_packet_new_response(unsigned mtu, int aa) { 78 AvahiDnsPacket *p; 79 80 if (!(p = avahi_dns_packet_new(mtu))) 81 return NULL; 82 83 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, aa, 0, 0, 0, 0, 0, 0, 0)); 84 return p; 85} 86 87AvahiDnsPacket* avahi_dns_packet_new_reply(AvahiDnsPacket* p, unsigned mtu, int copy_queries, int aa) { 88 AvahiDnsPacket *r; 89 assert(p); 90 91 if (!(r = avahi_dns_packet_new_response(mtu, aa))) 92 return NULL; 93 94 if (copy_queries) { 95 unsigned saved_rindex; 96 uint32_t n; 97 98 saved_rindex = p->rindex; 99 p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE; 100 101 for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); n > 0; n--) { 102 AvahiKey *k; 103 int unicast_response; 104 105 if ((k = avahi_dns_packet_consume_key(p, &unicast_response))) { 106 avahi_dns_packet_append_key(r, k, unicast_response); 107 avahi_key_unref(k); 108 } 109 } 110 111 p->rindex = saved_rindex; 112 113 avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_QDCOUNT, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT)); 114 } 115 116 avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_ID, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID)); 117 118 avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_FLAGS, 119 (avahi_dns_packet_get_field(r, AVAHI_DNS_FIELD_FLAGS) & ~AVAHI_DNS_FLAG_OPCODE) | 120 (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_OPCODE)); 121 122 return r; 123} 124 125 126void avahi_dns_packet_free(AvahiDnsPacket *p) { 127 assert(p); 128 129 if (p->name_table) 130 avahi_hashmap_free(p->name_table); 131 132 avahi_free(p); 133} 134 135void avahi_dns_packet_set_field(AvahiDnsPacket *p, unsigned idx, uint16_t v) { 136 assert(p); 137 assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE); 138 139 ((uint16_t*) AVAHI_DNS_PACKET_DATA(p))[idx] = htons(v); 140} 141 142uint16_t avahi_dns_packet_get_field(AvahiDnsPacket *p, unsigned idx) { 143 assert(p); 144 assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE); 145 146 return ntohs(((uint16_t*) AVAHI_DNS_PACKET_DATA(p))[idx]); 147} 148 149void avahi_dns_packet_inc_field(AvahiDnsPacket *p, unsigned idx) { 150 assert(p); 151 assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE); 152 153 avahi_dns_packet_set_field(p, idx, avahi_dns_packet_get_field(p, idx) + 1); 154} 155 156 157static void name_table_cleanup(void *key, void *value, void *user_data) { 158 AvahiDnsPacket *p = user_data; 159 160 if ((uint8_t*) value >= AVAHI_DNS_PACKET_DATA(p) + p->size) 161 avahi_hashmap_remove(p->name_table, key); 162} 163 164void avahi_dns_packet_cleanup_name_table(AvahiDnsPacket *p) { 165 if (p->name_table) 166 avahi_hashmap_foreach(p->name_table, name_table_cleanup, p); 167} 168 169uint8_t* avahi_dns_packet_append_name(AvahiDnsPacket *p, const char *name) { 170 uint8_t *d, *saved_ptr = NULL; 171 size_t saved_size; 172 173 assert(p); 174 assert(name); 175 176 saved_size = p->size; 177 saved_ptr = avahi_dns_packet_extend(p, 0); 178 179 while (*name) { 180 uint8_t* prev; 181 const char *pname; 182 char label[64], *u; 183 184 /* Check whether we can compress this name. */ 185 186 if (p->name_table && (prev = avahi_hashmap_lookup(p->name_table, name))) { 187 unsigned idx; 188 189 assert(prev >= AVAHI_DNS_PACKET_DATA(p)); 190 idx = (unsigned) (prev - AVAHI_DNS_PACKET_DATA(p)); 191 192 assert(idx < p->size); 193 194 if (idx < 0x4000) { 195 uint8_t *t; 196 if (!(t = (uint8_t*) avahi_dns_packet_extend(p, sizeof(uint16_t)))) 197 return NULL; 198 199 t[0] = (uint8_t) ((0xC000 | idx) >> 8); 200 t[1] = (uint8_t) idx; 201 return saved_ptr; 202 } 203 } 204 205 pname = name; 206 207 if (!(avahi_unescape_label(&name, label, sizeof(label)))) 208 goto fail; 209 210 if (!(d = avahi_dns_packet_append_string(p, label))) 211 goto fail; 212 213 if (!p->name_table) 214 /* This works only for normalized domain names */ 215 p->name_table = avahi_hashmap_new(avahi_string_hash, avahi_string_equal, avahi_free, NULL); 216 217 if (!(u = avahi_strdup(pname))) 218 avahi_log_error("avahi_strdup() failed."); 219 else 220 avahi_hashmap_insert(p->name_table, u, d); 221 } 222 223 if (!(d = avahi_dns_packet_extend(p, 1))) 224 goto fail; 225 226 *d = 0; 227 228 return saved_ptr; 229 230fail: 231 p->size = saved_size; 232 avahi_dns_packet_cleanup_name_table(p); 233 234 return NULL; 235} 236 237uint8_t* avahi_dns_packet_append_uint16(AvahiDnsPacket *p, uint16_t v) { 238 uint8_t *d; 239 assert(p); 240 241 if (!(d = avahi_dns_packet_extend(p, sizeof(uint16_t)))) 242 return NULL; 243 244 d[0] = (uint8_t) (v >> 8); 245 d[1] = (uint8_t) v; 246 return d; 247} 248 249uint8_t *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, uint32_t v) { 250 uint8_t *d; 251 assert(p); 252 253 if (!(d = avahi_dns_packet_extend(p, sizeof(uint32_t)))) 254 return NULL; 255 256 d[0] = (uint8_t) (v >> 24); 257 d[1] = (uint8_t) (v >> 16); 258 d[2] = (uint8_t) (v >> 8); 259 d[3] = (uint8_t) v; 260 261 return d; 262} 263 264uint8_t *avahi_dns_packet_append_bytes(AvahiDnsPacket *p, const void *b, size_t l) { 265 uint8_t* d; 266 267 assert(p); 268 assert(b); 269 assert(l); 270 271 if (!(d = avahi_dns_packet_extend(p, l))) 272 return NULL; 273 274 memcpy(d, b, l); 275 return d; 276} 277 278uint8_t* avahi_dns_packet_append_string(AvahiDnsPacket *p, const char *s) { 279 uint8_t* d; 280 size_t k; 281 282 assert(p); 283 assert(s); 284 285 if ((k = strlen(s)) >= 255) 286 k = 255; 287 288 if (!(d = avahi_dns_packet_extend(p, k+1))) 289 return NULL; 290 291 *d = (uint8_t) k; 292 memcpy(d+1, s, k); 293 294 return d; 295} 296 297uint8_t *avahi_dns_packet_extend(AvahiDnsPacket *p, size_t l) { 298 uint8_t *d; 299 300 assert(p); 301 302 if (p->size+l > p->max_size) 303 return NULL; 304 305 d = AVAHI_DNS_PACKET_DATA(p) + p->size; 306 p->size += l; 307 308 return d; 309} 310 311int avahi_dns_packet_check_valid(AvahiDnsPacket *p) { 312 uint16_t flags; 313 assert(p); 314 315 if (p->size < AVAHI_DNS_PACKET_HEADER_SIZE) 316 return -1; 317 318 flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS); 319 320 if (flags & AVAHI_DNS_FLAG_OPCODE) 321 return -1; 322 323 return 0; 324} 325 326int avahi_dns_packet_check_valid_multicast(AvahiDnsPacket *p) { 327 uint16_t flags; 328 assert(p); 329 330 if (avahi_dns_packet_check_valid(p) < 0) 331 return -1; 332 333 flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS); 334 335 if (flags & AVAHI_DNS_FLAG_RCODE) 336 return -1; 337 338 return 0; 339} 340 341int avahi_dns_packet_is_query(AvahiDnsPacket *p) { 342 assert(p); 343 344 return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR); 345} 346 347static int consume_labels(AvahiDnsPacket *p, unsigned idx, char *ret_name, size_t l) { 348 int ret = 0; 349 int compressed = 0; 350 int first_label = 1; 351 unsigned label_ptr; 352 int i; 353 assert(p && ret_name && l); 354 355 for (i = 0; i < AVAHI_DNS_LABELS_MAX; i++) { 356 uint8_t n; 357 358 if (idx+1 > p->size) 359 return -1; 360 361 n = AVAHI_DNS_PACKET_DATA(p)[idx]; 362 363 if (!n) { 364 idx++; 365 if (!compressed) 366 ret++; 367 368 if (l < 1) 369 return -1; 370 *ret_name = 0; 371 372 return ret; 373 374 } else if (n <= 63) { 375 /* Uncompressed label */ 376 idx++; 377 if (!compressed) 378 ret++; 379 380 if (idx + n > p->size) 381 return -1; 382 383 if ((size_t) n + 1 > l) 384 return -1; 385 386 if (!first_label) { 387 *(ret_name++) = '.'; 388 l--; 389 } else 390 first_label = 0; 391 392 if (!(avahi_escape_label((char*) AVAHI_DNS_PACKET_DATA(p) + idx, n, &ret_name, &l))) 393 return -1; 394 395 idx += n; 396 397 if (!compressed) 398 ret += n; 399 } else if ((n & 0xC0) == 0xC0) { 400 /* Compressed label */ 401 402 if (idx+2 > p->size) 403 return -1; 404 405 label_ptr = ((unsigned) (AVAHI_DNS_PACKET_DATA(p)[idx] & ~0xC0)) << 8 | AVAHI_DNS_PACKET_DATA(p)[idx+1]; 406 407 if ((label_ptr < AVAHI_DNS_PACKET_HEADER_SIZE) || (label_ptr >= idx)) 408 return -1; 409 410 idx = label_ptr; 411 412 if (!compressed) 413 ret += 2; 414 415 compressed = 1; 416 } else 417 return -1; 418 } 419 420 return -1; 421} 422 423int avahi_dns_packet_consume_name(AvahiDnsPacket *p, char *ret_name, size_t l) { 424 int r; 425 426 if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0) 427 return -1; 428 429 p->rindex += r; 430 return 0; 431} 432 433int avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, uint16_t *ret_v) { 434 uint8_t *d; 435 436 assert(p); 437 assert(ret_v); 438 439 if (p->rindex + sizeof(uint16_t) > p->size) 440 return -1; 441 442 d = (uint8_t*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex); 443 *ret_v = (d[0] << 8) | d[1]; 444 p->rindex += sizeof(uint16_t); 445 446 return 0; 447} 448 449int avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, uint32_t *ret_v) { 450 uint8_t* d; 451 452 assert(p); 453 assert(ret_v); 454 455 if (p->rindex + sizeof(uint32_t) > p->size) 456 return -1; 457 458 d = (uint8_t*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex); 459 *ret_v = (d[0] << 24) | (d[1] << 16) | (d[2] << 8) | d[3]; 460 p->rindex += sizeof(uint32_t); 461 462 return 0; 463} 464 465int avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, void * ret_data, size_t l) { 466 assert(p); 467 assert(ret_data); 468 assert(l > 0); 469 470 if (p->rindex + l > p->size) 471 return -1; 472 473 memcpy(ret_data, AVAHI_DNS_PACKET_DATA(p) + p->rindex, l); 474 p->rindex += l; 475 476 return 0; 477} 478 479int avahi_dns_packet_consume_string(AvahiDnsPacket *p, char *ret_string, size_t l) { 480 size_t k; 481 482 assert(p); 483 assert(ret_string); 484 assert(l > 0); 485 486 if (p->rindex >= p->size) 487 return -1; 488 489 k = AVAHI_DNS_PACKET_DATA(p)[p->rindex]; 490 491 if (p->rindex+1+k > p->size) 492 return -1; 493 494 if (l > k+1) 495 l = k+1; 496 497 memcpy(ret_string, AVAHI_DNS_PACKET_DATA(p)+p->rindex+1, l-1); 498 ret_string[l-1] = 0; 499 500 p->rindex += 1+k; 501 502 return 0; 503} 504 505const void* avahi_dns_packet_get_rptr(AvahiDnsPacket *p) { 506 assert(p); 507 508 if (p->rindex > p->size) 509 return NULL; 510 511 return AVAHI_DNS_PACKET_DATA(p) + p->rindex; 512} 513 514int avahi_dns_packet_skip(AvahiDnsPacket *p, size_t length) { 515 assert(p); 516 517 if (p->rindex + length > p->size) 518 return -1; 519 520 p->rindex += length; 521 return 0; 522} 523 524static int parse_rdata(AvahiDnsPacket *p, AvahiRecord *r, uint16_t rdlength) { 525 char buf[AVAHI_DOMAIN_NAME_MAX]; 526 const void* start; 527 528 assert(p); 529 assert(r); 530 531 start = avahi_dns_packet_get_rptr(p); 532 533 switch (r->key->type) { 534 case AVAHI_DNS_TYPE_PTR: 535 case AVAHI_DNS_TYPE_CNAME: 536 case AVAHI_DNS_TYPE_NS: 537 538 if (avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0) 539 return -1; 540 541 r->data.ptr.name = avahi_strdup(buf); 542 break; 543 544 545 case AVAHI_DNS_TYPE_SRV: 546 547 if (avahi_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 || 548 avahi_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 || 549 avahi_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 || 550 avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0) 551 return -1; 552 553 r->data.srv.name = avahi_strdup(buf); 554 break; 555 556 case AVAHI_DNS_TYPE_HINFO: 557 558 if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0) 559 return -1; 560 561 r->data.hinfo.cpu = avahi_strdup(buf); 562 563 if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0) 564 return -1; 565 566 r->data.hinfo.os = avahi_strdup(buf); 567 break; 568 569 case AVAHI_DNS_TYPE_TXT: 570 571 if (rdlength > 0) { 572 if (avahi_string_list_parse(avahi_dns_packet_get_rptr(p), rdlength, &r->data.txt.string_list) < 0) 573 return -1; 574 575 if (avahi_dns_packet_skip(p, rdlength) < 0) 576 return -1; 577 } else 578 r->data.txt.string_list = NULL; 579 580 break; 581 582 case AVAHI_DNS_TYPE_A: 583 584/* avahi_log_debug("A"); */ 585 586 if (avahi_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(AvahiIPv4Address)) < 0) 587 return -1; 588 589 break; 590 591 case AVAHI_DNS_TYPE_AAAA: 592 593/* avahi_log_debug("aaaa"); */ 594 595 if (avahi_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(AvahiIPv6Address)) < 0) 596 return -1; 597 598 break; 599 600 default: 601 602/* avahi_log_debug("generic"); */ 603 604 if (rdlength > 0) { 605 606 r->data.generic.data = avahi_memdup(avahi_dns_packet_get_rptr(p), rdlength); 607 r->data.generic.size = rdlength; 608 609 if (avahi_dns_packet_skip(p, rdlength) < 0) 610 return -1; 611 } 612 613 break; 614 } 615 616 /* Check if we read enough data */ 617 if ((const uint8_t*) avahi_dns_packet_get_rptr(p) - (const uint8_t*) start != rdlength) 618 return -1; 619 620 return 0; 621} 622 623AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, int *ret_cache_flush) { 624 char name[AVAHI_DOMAIN_NAME_MAX]; 625 uint16_t type, class; 626 uint32_t ttl; 627 uint16_t rdlength; 628 AvahiRecord *r = NULL; 629 630 assert(p); 631 632 if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 || 633 avahi_dns_packet_consume_uint16(p, &type) < 0 || 634 avahi_dns_packet_consume_uint16(p, &class) < 0 || 635 avahi_dns_packet_consume_uint32(p, &ttl) < 0 || 636 avahi_dns_packet_consume_uint16(p, &rdlength) < 0 || 637 p->rindex + rdlength > p->size) 638 goto fail; 639 640 if (ret_cache_flush) 641 *ret_cache_flush = !!(class & AVAHI_DNS_CACHE_FLUSH); 642 class &= ~AVAHI_DNS_CACHE_FLUSH; 643 644 if (!(r = avahi_record_new_full(name, class, type, ttl))) 645 goto fail; 646 647 if (parse_rdata(p, r, rdlength) < 0) 648 goto fail; 649 650 if (!avahi_record_is_valid(r)) 651 goto fail; 652 653 return r; 654 655fail: 656 if (r) 657 avahi_record_unref(r); 658 659 return NULL; 660} 661 662AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, int *ret_unicast_response) { 663 char name[256]; 664 uint16_t type, class; 665 AvahiKey *k; 666 667 assert(p); 668 669 if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 || 670 avahi_dns_packet_consume_uint16(p, &type) < 0 || 671 avahi_dns_packet_consume_uint16(p, &class) < 0) 672 return NULL; 673 674 if (ret_unicast_response) 675 *ret_unicast_response = !!(class & AVAHI_DNS_UNICAST_RESPONSE); 676 677 class &= ~AVAHI_DNS_UNICAST_RESPONSE; 678 679 if (!(k = avahi_key_new(name, class, type))) 680 return NULL; 681 682 if (!avahi_key_is_valid(k)) { 683 avahi_key_unref(k); 684 return NULL; 685 } 686 687 return k; 688} 689 690uint8_t* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, int unicast_response) { 691 uint8_t *t; 692 size_t size; 693 694 assert(p); 695 assert(k); 696 697 size = p->size; 698 699 if (!(t = avahi_dns_packet_append_name(p, k->name)) || 700 !avahi_dns_packet_append_uint16(p, k->type) || 701 !avahi_dns_packet_append_uint16(p, k->clazz | (unicast_response ? AVAHI_DNS_UNICAST_RESPONSE : 0))) { 702 p->size = size; 703 avahi_dns_packet_cleanup_name_table(p); 704 705 return NULL; 706 } 707 708 return t; 709} 710 711static int append_rdata(AvahiDnsPacket *p, AvahiRecord *r) { 712 assert(p); 713 assert(r); 714 715 switch (r->key->type) { 716 717 case AVAHI_DNS_TYPE_PTR: 718 case AVAHI_DNS_TYPE_CNAME: 719 case AVAHI_DNS_TYPE_NS: 720 721 if (!(avahi_dns_packet_append_name(p, r->data.ptr.name))) 722 return -1; 723 724 break; 725 726 case AVAHI_DNS_TYPE_SRV: 727 728 if (!avahi_dns_packet_append_uint16(p, r->data.srv.priority) || 729 !avahi_dns_packet_append_uint16(p, r->data.srv.weight) || 730 !avahi_dns_packet_append_uint16(p, r->data.srv.port) || 731 !avahi_dns_packet_append_name(p, r->data.srv.name)) 732 return -1; 733 734 break; 735 736 case AVAHI_DNS_TYPE_HINFO: 737 if (!avahi_dns_packet_append_string(p, r->data.hinfo.cpu) || 738 !avahi_dns_packet_append_string(p, r->data.hinfo.os)) 739 return -1; 740 741 break; 742 743 case AVAHI_DNS_TYPE_TXT: { 744 745 uint8_t *data; 746 size_t n; 747 748 n = avahi_string_list_serialize(r->data.txt.string_list, NULL, 0); 749 750 if (!(data = avahi_dns_packet_extend(p, n))) 751 return -1; 752 753 avahi_string_list_serialize(r->data.txt.string_list, data, n); 754 break; 755 } 756 757 758 case AVAHI_DNS_TYPE_A: 759 760 if (!avahi_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address))) 761 return -1; 762 763 break; 764 765 case AVAHI_DNS_TYPE_AAAA: 766 767 if (!avahi_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address))) 768 return -1; 769 770 break; 771 772 default: 773 774 if (r->data.generic.size) 775 if (!avahi_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size)) 776 return -1; 777 778 break; 779 } 780 781 return 0; 782} 783 784 785uint8_t* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, int cache_flush, unsigned max_ttl) { 786 uint8_t *t, *l, *start; 787 size_t size; 788 789 assert(p); 790 assert(r); 791 792 size = p->size; 793 794 if (!(t = avahi_dns_packet_append_name(p, r->key->name)) || 795 !avahi_dns_packet_append_uint16(p, r->key->type) || 796 !avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->clazz | AVAHI_DNS_CACHE_FLUSH) : (r->key->clazz &~ AVAHI_DNS_CACHE_FLUSH)) || 797 !avahi_dns_packet_append_uint32(p, (max_ttl && r->ttl > max_ttl) ? max_ttl : r->ttl) || 798 !(l = avahi_dns_packet_append_uint16(p, 0))) 799 goto fail; 800 801 start = avahi_dns_packet_extend(p, 0); 802 803 if (append_rdata(p, r) < 0) 804 goto fail; 805 806 size = avahi_dns_packet_extend(p, 0) - start; 807 assert(size <= AVAHI_DNS_RDATA_MAX); 808 809/* avahi_log_debug("appended %u", size); */ 810 811 l[0] = (uint8_t) ((uint16_t) size >> 8); 812 l[1] = (uint8_t) ((uint16_t) size); 813 814 return t; 815 816 817fail: 818 p->size = size; 819 avahi_dns_packet_cleanup_name_table(p); 820 821 return NULL; 822} 823 824int avahi_dns_packet_is_empty(AvahiDnsPacket *p) { 825 assert(p); 826 827 return p->size <= AVAHI_DNS_PACKET_HEADER_SIZE; 828} 829 830size_t avahi_dns_packet_space(AvahiDnsPacket *p) { 831 assert(p); 832 833 assert(p->size <= p->max_size); 834 835 return p->max_size - p->size; 836} 837 838int avahi_rdata_parse(AvahiRecord *record, const void* rdata, size_t size) { 839 int ret; 840 AvahiDnsPacket p; 841 842 assert(record); 843 assert(rdata); 844 845 p.data = (void*) rdata; 846 p.max_size = p.size = size; 847 p.rindex = 0; 848 p.name_table = NULL; 849 850 ret = parse_rdata(&p, record, size); 851 852 assert(!p.name_table); 853 854 return ret; 855} 856 857size_t avahi_rdata_serialize(AvahiRecord *record, void *rdata, size_t max_size) { 858 int ret; 859 AvahiDnsPacket p; 860 861 assert(record); 862 assert(rdata); 863 assert(max_size > 0); 864 865 p.data = (void*) rdata; 866 p.max_size = max_size; 867 p.size = p.rindex = 0; 868 p.name_table = NULL; 869 870 ret = append_rdata(&p, record); 871 872 if (p.name_table) 873 avahi_hashmap_free(p.name_table); 874 875 if (ret < 0) 876 return (size_t) -1; 877 878 return p.size; 879} 880