1 /* 2 * query.c -- nsd(8) the resolver. 3 * 4 * Copyright (c) 2001-2006, NLnet Labs. All rights reserved. 5 * 6 * See LICENSE for the license. 7 * 8 */ 9 10 #include "config.h" 11 12 #include <sys/types.h> 13 #include <sys/socket.h> 14 #include <netinet/in.h> 15 #include <arpa/inet.h> 16 #include <assert.h> 17 #include <ctype.h> 18 #include <errno.h> 19 #include <limits.h> 20 #include <stddef.h> 21 #include <stdio.h> 22 #include <stdlib.h> 23 #include <string.h> 24 #include <time.h> 25 #include <unistd.h> 26 #include <netdb.h> 27 28 #include "answer.h" 29 #include "axfr.h" 30 #include "dns.h" 31 #include "dname.h" 32 #include "nsd.h" 33 #include "namedb.h" 34 #include "query.h" 35 #include "util.h" 36 #include "options.h" 37 #include "nsec3.h" 38 #include "tsig.h" 39 40 /* [Bug #253] Adding unnecessary NS RRset may lead to undesired truncation. 41 * This function determines if the final response packet needs the NS RRset 42 * included. Currently, it will only return negative if QTYPE == DNSKEY|DS. 43 * This way, resolvers won't fallback to TCP unnecessarily when priming 44 * trust anchors. 45 */ 46 static int answer_needs_ns(struct query *query); 47 48 static int add_rrset(struct query *query, 49 answer_type *answer, 50 rr_section_type section, 51 domain_type *owner, 52 rrset_type *rrset); 53 54 static void answer_authoritative(struct nsd *nsd, 55 struct query *q, 56 answer_type *answer, 57 size_t domain_number, 58 int exact, 59 domain_type *closest_match, 60 domain_type *closest_encloser, 61 const dname_type *qname); 62 63 static void answer_lookup_zone(struct nsd *nsd, struct query *q, 64 answer_type *answer, size_t domain_number, 65 int exact, domain_type *closest_match, 66 domain_type *closest_encloser, 67 const dname_type *qname); 68 69 void 70 query_put_dname_offset(struct query *q, domain_type *domain, uint16_t offset) 71 { 72 assert(q); 73 assert(domain); 74 assert(domain->number > 0); 75 76 if (offset > MAX_COMPRESSION_OFFSET) 77 return; 78 if (q->compressed_dname_count >= MAX_COMPRESSED_DNAMES) 79 return; 80 81 q->compressed_dname_offsets[domain->number] = offset; 82 q->compressed_dnames[q->compressed_dname_count] = domain; 83 ++q->compressed_dname_count; 84 } 85 86 void 87 query_clear_dname_offsets(struct query *q, size_t max_offset) 88 { 89 while (q->compressed_dname_count > 0 90 && (q->compressed_dname_offsets[q->compressed_dnames[q->compressed_dname_count - 1]->number] 91 >= max_offset)) 92 { 93 q->compressed_dname_offsets[q->compressed_dnames[q->compressed_dname_count - 1]->number] = 0; 94 --q->compressed_dname_count; 95 } 96 } 97 98 void 99 query_clear_compression_tables(struct query *q) 100 { 101 uint16_t i; 102 103 for (i = 0; i < q->compressed_dname_count; ++i) { 104 assert(q->compressed_dnames); 105 q->compressed_dname_offsets[q->compressed_dnames[i]->number] = 0; 106 } 107 q->compressed_dname_count = 0; 108 } 109 110 void 111 query_add_compression_domain(struct query *q, domain_type *domain, uint16_t offset) 112 { 113 while (domain->parent) { 114 DEBUG(DEBUG_NAME_COMPRESSION, 2, 115 (LOG_INFO, "query dname: %s, number: %lu, offset: %u\n", 116 domain_to_string(domain), 117 (unsigned long) domain->number, 118 offset)); 119 query_put_dname_offset(q, domain, offset); 120 offset += label_length(dname_name(domain_dname(domain))) + 1; 121 domain = domain->parent; 122 } 123 } 124 125 /* 126 * Generate an error response with the specified RCODE. 127 */ 128 query_state_type 129 query_error (struct query *q, nsd_rc_type rcode) 130 { 131 if (rcode == NSD_RC_DISCARD) { 132 return QUERY_DISCARDED; 133 } 134 135 buffer_clear(q->packet); 136 137 QR_SET(q->packet); /* This is an answer. */ 138 AD_CLR(q->packet); 139 RCODE_SET(q->packet, (int) rcode); /* Error code. */ 140 141 /* Truncate the question as well... */ 142 QDCOUNT_SET(q->packet, 0); 143 ANCOUNT_SET(q->packet, 0); 144 NSCOUNT_SET(q->packet, 0); 145 ARCOUNT_SET(q->packet, 0); 146 buffer_set_position(q->packet, QHEADERSZ); 147 return QUERY_PROCESSED; 148 } 149 150 static int 151 query_ratelimit_err(nsd_type* nsd) 152 { 153 time_t now = time(NULL); 154 if(nsd->err_limit_time == now) { 155 /* see if limit is exceeded for this second */ 156 if(nsd->err_limit_count++ > ERROR_RATELIMIT) 157 return 1; 158 } else { 159 /* new second, new limits */ 160 nsd->err_limit_time = now; 161 nsd->err_limit_count = 1; 162 } 163 return 0; 164 } 165 166 static query_state_type 167 query_formerr (struct query *query, nsd_type* nsd) 168 { 169 int opcode = OPCODE(query->packet); 170 if(query_ratelimit_err(nsd)) 171 return QUERY_DISCARDED; 172 FLAGS_SET(query->packet, FLAGS(query->packet) & 0x0100U); 173 /* Preserve the RD flag. Clear the rest. */ 174 OPCODE_SET(query->packet, opcode); 175 return query_error(query, NSD_RC_FORMAT); 176 } 177 178 static void 179 query_cleanup(void *data) 180 { 181 query_type *query = (query_type *) data; 182 region_destroy(query->region); 183 } 184 185 query_type * 186 query_create(region_type *region, uint16_t *compressed_dname_offsets, 187 size_t compressed_dname_size) 188 { 189 query_type *query 190 = (query_type *) region_alloc_zero(region, sizeof(query_type)); 191 /* create region with large block size, because the initial chunk 192 saves many mallocs in the server */ 193 query->region = region_create_custom(xalloc, free, 16384, 16384/8, 32, 0); 194 query->compressed_dname_offsets = compressed_dname_offsets; 195 query->packet = buffer_create(region, QIOBUFSZ); 196 region_add_cleanup(region, query_cleanup, query); 197 query->compressed_dname_offsets_size = compressed_dname_size; 198 tsig_create_record(&query->tsig, region); 199 query->tsig_prepare_it = 1; 200 query->tsig_update_it = 1; 201 query->tsig_sign_it = 1; 202 return query; 203 } 204 205 void 206 query_reset(query_type *q, size_t maxlen, int is_tcp) 207 { 208 /* 209 * As long as less than 4Kb (region block size) has been used, 210 * this call to free_all is free, the block is saved for re-use, 211 * so no malloc() or free() calls are done. 212 * at present use of the region is for: 213 * o query qname dname_type (255 max). 214 * o wildcard expansion domain_type (7*ptr+u32+2bytes)+(5*ptr nsec3) 215 * o wildcard expansion for additional section domain_type. 216 * o nsec3 hashed name(s) (3 dnames for a nonexist_proof, 217 * one proof per wildcard and for nx domain). 218 */ 219 region_free_all(q->region); 220 q->addrlen = sizeof(q->addr); 221 q->maxlen = maxlen; 222 q->reserved_space = 0; 223 buffer_clear(q->packet); 224 edns_init_record(&q->edns); 225 tsig_init_record(&q->tsig, NULL, NULL); 226 q->tsig_prepare_it = 1; 227 q->tsig_update_it = 1; 228 q->tsig_sign_it = 1; 229 q->tcp = is_tcp; 230 q->qname = NULL; 231 q->qtype = 0; 232 q->qclass = 0; 233 q->zone = NULL; 234 q->opcode = 0; 235 q->cname_count = 0; 236 q->delegation_domain = NULL; 237 q->delegation_rrset = NULL; 238 q->compressed_dname_count = 0; 239 q->number_temporary_domains = 0; 240 241 q->axfr_is_done = 0; 242 q->axfr_zone = NULL; 243 q->axfr_current_domain = NULL; 244 q->axfr_current_rrset = NULL; 245 q->axfr_current_rr = 0; 246 247 #ifdef RATELIMIT 248 q->wildcard_domain = NULL; 249 #endif 250 } 251 252 /* get a temporary domain number (or 0=failure) */ 253 static domain_type* 254 query_get_tempdomain(struct query *q) 255 { 256 static domain_type d[EXTRA_DOMAIN_NUMBERS]; 257 if(q->number_temporary_domains >= EXTRA_DOMAIN_NUMBERS) 258 return 0; 259 q->number_temporary_domains ++; 260 memset(&d[q->number_temporary_domains-1], 0, sizeof(domain_type)); 261 d[q->number_temporary_domains-1].number = q->compressed_dname_offsets_size + 262 q->number_temporary_domains - 1; 263 return &d[q->number_temporary_domains-1]; 264 } 265 266 static void 267 query_addtxt(struct query *q, 268 const uint8_t *dname, 269 uint16_t klass, 270 uint32_t ttl, 271 const char *txt) 272 { 273 size_t txt_length = strlen(txt); 274 uint8_t len = (uint8_t) txt_length; 275 276 assert(txt_length <= UCHAR_MAX); 277 278 /* Add the dname */ 279 if (dname >= buffer_begin(q->packet) 280 && dname <= buffer_current(q->packet)) 281 { 282 buffer_write_u16(q->packet, 283 0xc000 | (dname - buffer_begin(q->packet))); 284 } else { 285 buffer_write(q->packet, dname + 1, *dname); 286 } 287 288 buffer_write_u16(q->packet, TYPE_TXT); 289 buffer_write_u16(q->packet, klass); 290 buffer_write_u32(q->packet, ttl); 291 buffer_write_u16(q->packet, len + 1); 292 buffer_write_u8(q->packet, len); 293 buffer_write(q->packet, txt, len); 294 } 295 296 /* 297 * Parse the question section of a query. The normalized query name 298 * is stored in QUERY->name, the class in QUERY->klass, and the type 299 * in QUERY->type. 300 */ 301 static int 302 process_query_section(query_type *query) 303 { 304 uint8_t qnamebuf[MAXDOMAINLEN]; 305 306 buffer_set_position(query->packet, QHEADERSZ); 307 /* Lets parse the query name and convert it to lower case. */ 308 if(!packet_read_query_section(query->packet, qnamebuf, 309 &query->qtype, &query->qclass)) 310 return 0; 311 query->qname = dname_make(query->region, qnamebuf, 1); 312 return 1; 313 } 314 315 316 /* 317 * Process an optional EDNS OPT record. Sets QUERY->EDNS to 0 if 318 * there was no EDNS record, to -1 if there was an invalid or 319 * unsupported EDNS record, and to 1 otherwise. Updates QUERY->MAXLEN 320 * if the EDNS record specifies a maximum supported response length. 321 * 322 * Return NSD_RC_FORMAT on failure, NSD_RC_OK on success. 323 */ 324 static nsd_rc_type 325 process_edns(nsd_type* nsd, struct query *q) 326 { 327 if (q->edns.status == EDNS_ERROR) { 328 /* The only error is VERSION not implemented */ 329 return NSD_RC_FORMAT; 330 } 331 332 if (q->edns.status == EDNS_OK) { 333 /* Only care about UDP size larger than normal... */ 334 if (!q->tcp && q->edns.maxlen > UDP_MAX_MESSAGE_LEN) { 335 size_t edns_size; 336 #if defined(INET6) 337 if (q->addr.ss_family == AF_INET6) { 338 edns_size = nsd->ipv6_edns_size; 339 } else 340 #endif 341 edns_size = nsd->ipv4_edns_size; 342 343 if (q->edns.maxlen < edns_size) { 344 q->maxlen = q->edns.maxlen; 345 } else { 346 q->maxlen = edns_size; 347 } 348 349 #if defined(INET6) && !defined(IPV6_USE_MIN_MTU) && !defined(IPV6_MTU) 350 /* 351 * Use IPv6 minimum MTU to avoid sending 352 * packets that are too large for some links. 353 * IPv6 will not automatically fragment in 354 * this case (unlike IPv4). 355 */ 356 if (q->addr.ss_family == AF_INET6 357 && q->maxlen > IPV6_MIN_MTU) 358 { 359 q->maxlen = IPV6_MIN_MTU; 360 } 361 #endif 362 } 363 364 /* Strip the OPT resource record off... */ 365 buffer_set_position(q->packet, q->edns.position); 366 buffer_set_limit(q->packet, q->edns.position); 367 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) - 1); 368 } 369 return NSD_RC_OK; 370 } 371 372 /* 373 * Processes TSIG. 374 * Sets error when tsig does not verify on the query. 375 */ 376 static nsd_rc_type 377 process_tsig(struct query* q) 378 { 379 if(q->tsig.status == TSIG_ERROR) 380 return NSD_RC_FORMAT; 381 if(q->tsig.status == TSIG_OK) { 382 if(!tsig_from_query(&q->tsig)) { 383 char a[128]; 384 addr2str(&q->addr, a, sizeof(a)); 385 log_msg(LOG_ERR, "query: bad tsig (%s) for key %s from %s", 386 tsig_error(q->tsig.error_code), 387 dname_to_string(q->tsig.key_name, NULL), a); 388 return NSD_RC_NOTAUTH; 389 } 390 buffer_set_limit(q->packet, q->tsig.position); 391 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) - 1); 392 tsig_prepare(&q->tsig); 393 tsig_update(&q->tsig, q->packet, buffer_limit(q->packet)); 394 if(!tsig_verify(&q->tsig)) { 395 char a[128]; 396 addr2str(&q->addr, a, sizeof(a)); 397 log_msg(LOG_ERR, "query: bad tsig signature for key %s from %s", 398 dname_to_string(q->tsig.key->name, NULL), a); 399 return NSD_RC_NOTAUTH; 400 } 401 DEBUG(DEBUG_XFRD,1, (LOG_INFO, "query good tsig signature for %s", 402 dname_to_string(q->tsig.key->name, NULL))); 403 } 404 return NSD_RC_OK; 405 } 406 407 /* 408 * Check notify acl and forward to xfrd (or return an error). 409 */ 410 static query_state_type 411 answer_notify(struct nsd* nsd, struct query *query) 412 { 413 int acl_num, acl_num_xfr; 414 acl_options_t *why; 415 nsd_rc_type rc; 416 417 zone_options_t* zone_opt; 418 DEBUG(DEBUG_XFRD,1, (LOG_INFO, "got notify %s processing acl", 419 dname_to_string(query->qname, NULL))); 420 421 zone_opt = zone_options_find(nsd->options, query->qname); 422 if(!zone_opt) 423 return query_error(query, NSD_RC_NXDOMAIN); 424 425 if(!nsd->this_child) /* we are in debug mode or something */ 426 return query_error(query, NSD_RC_SERVFAIL); 427 428 if(!tsig_find_rr(&query->tsig, query->packet)) { 429 DEBUG(DEBUG_XFRD,2, (LOG_ERR, "bad tsig RR format")); 430 return query_error(query, NSD_RC_FORMAT); 431 } 432 rc = process_tsig(query); 433 if(rc != NSD_RC_OK) 434 return query_error(query, rc); 435 436 /* check if it passes acl */ 437 if((acl_num = acl_check_incoming(zone_opt->pattern->allow_notify, query, 438 &why)) != -1) 439 { 440 sig_atomic_t mode = NSD_PASS_TO_XFRD; 441 int s = nsd->this_child->parent_fd; 442 uint16_t sz; 443 uint32_t acl_send = htonl(acl_num); 444 uint32_t acl_xfr; 445 size_t pos; 446 447 /* Find priority candidate for request XFR. -1 if no match */ 448 acl_num_xfr = acl_check_incoming( 449 zone_opt->pattern->request_xfr, query, NULL); 450 451 acl_xfr = htonl(acl_num_xfr); 452 453 assert(why); 454 DEBUG(DEBUG_XFRD,1, (LOG_INFO, "got notify %s passed acl %s %s", 455 dname_to_string(query->qname, NULL), 456 why->ip_address_spec, 457 why->nokey?"NOKEY": 458 (why->blocked?"BLOCKED":why->key_name))); 459 sz = buffer_limit(query->packet); 460 if(buffer_limit(query->packet) > MAX_PACKET_SIZE) 461 return query_error(query, NSD_RC_SERVFAIL); 462 /* forward to xfrd for processing 463 Note. Blocking IPC I/O, but acl is OK. */ 464 sz = htons(sz); 465 if(!write_socket(s, &mode, sizeof(mode)) || 466 !write_socket(s, &sz, sizeof(sz)) || 467 !write_socket(s, buffer_begin(query->packet), 468 buffer_limit(query->packet)) || 469 !write_socket(s, &acl_send, sizeof(acl_send)) || 470 !write_socket(s, &acl_xfr, sizeof(acl_xfr))) { 471 log_msg(LOG_ERR, "error in IPC notify server2main, %s", 472 strerror(errno)); 473 return query_error(query, NSD_RC_SERVFAIL); 474 } 475 if(verbosity >= 1) { 476 uint32_t serial = 0; 477 char address[128]; 478 addr2str(&query->addr, address, sizeof(address)); 479 if(packet_find_notify_serial(query->packet, &serial)) 480 VERBOSITY(1, (LOG_INFO, "notify for %s from %s serial %u", 481 dname_to_string(query->qname, NULL), address, 482 (unsigned)serial)); 483 else 484 VERBOSITY(1, (LOG_INFO, "notify for %s from %s", 485 dname_to_string(query->qname, NULL), address)); 486 } 487 488 /* create notify reply - keep same query contents */ 489 QR_SET(query->packet); /* This is an answer. */ 490 AA_SET(query->packet); /* we are authoritative. */ 491 ANCOUNT_SET(query->packet, 0); 492 NSCOUNT_SET(query->packet, 0); 493 ARCOUNT_SET(query->packet, 0); 494 RCODE_SET(query->packet, RCODE_OK); /* Error code. */ 495 /* position is right after the query */ 496 pos = buffer_position(query->packet); 497 buffer_clear(query->packet); 498 buffer_set_position(query->packet, pos); 499 /* tsig is added in add_additional later (if needed) */ 500 return QUERY_PROCESSED; 501 } 502 503 if (verbosity >= 2) { 504 char address[128]; 505 addr2str(&query->addr, address, sizeof(address)); 506 VERBOSITY(2, (LOG_INFO, "notify for %s from %s refused, %s%s", 507 dname_to_string(query->qname, NULL), 508 address, 509 why?why->key_name:"no acl matches", 510 why?why->ip_address_spec:".")); 511 } 512 513 return query_error(query, NSD_RC_REFUSE); 514 } 515 516 517 /* 518 * Answer a query in the CHAOS class. 519 */ 520 static query_state_type 521 answer_chaos(struct nsd *nsd, query_type *q) 522 { 523 AA_CLR(q->packet); 524 switch (q->qtype) { 525 case TYPE_ANY: 526 case TYPE_TXT: 527 if ((q->qname->name_size == 11 528 && memcmp(dname_name(q->qname), "\002id\006server", 11) == 0) || 529 (q->qname->name_size == 15 530 && memcmp(dname_name(q->qname), "\010hostname\004bind", 15) == 0)) 531 { 532 /* Add ID */ 533 query_addtxt(q, 534 buffer_begin(q->packet) + QHEADERSZ, 535 CLASS_CH, 536 0, 537 nsd->identity); 538 ANCOUNT_SET(q->packet, ANCOUNT(q->packet) + 1); 539 } else if ((q->qname->name_size == 16 540 && memcmp(dname_name(q->qname), "\007version\006server", 16) == 0) || 541 (q->qname->name_size == 14 542 && memcmp(dname_name(q->qname), "\007version\004bind", 14) == 0)) 543 { 544 if(!nsd->options->hide_version) { 545 /* Add version */ 546 query_addtxt(q, 547 buffer_begin(q->packet) + QHEADERSZ, 548 CLASS_CH, 549 0, 550 nsd->version); 551 ANCOUNT_SET(q->packet, ANCOUNT(q->packet) + 1); 552 } else { 553 RCODE_SET(q->packet, RCODE_REFUSE); 554 } 555 } else { 556 RCODE_SET(q->packet, RCODE_REFUSE); 557 } 558 break; 559 default: 560 RCODE_SET(q->packet, RCODE_REFUSE); 561 break; 562 } 563 564 return QUERY_PROCESSED; 565 } 566 567 568 /* 569 * Find the covering NSEC for a non-existent domain name. Normally 570 * the NSEC will be located at CLOSEST_MATCH, except when it is an 571 * empty non-terminal. In this case the NSEC may be located at the 572 * previous domain name (in canonical ordering). 573 */ 574 static domain_type * 575 find_covering_nsec(domain_type *closest_match, 576 zone_type *zone, 577 rrset_type **nsec_rrset) 578 { 579 assert(closest_match); 580 assert(nsec_rrset); 581 582 /* loop away temporary created domains. For real ones it is &RBTREE_NULL */ 583 while (closest_match->rnode == NULL) 584 closest_match = closest_match->parent; 585 while (closest_match) { 586 *nsec_rrset = domain_find_rrset(closest_match, zone, TYPE_NSEC); 587 if (*nsec_rrset) { 588 return closest_match; 589 } 590 if (closest_match == zone->apex) { 591 /* Don't look outside the current zone. */ 592 return NULL; 593 } 594 closest_match = domain_previous(closest_match); 595 } 596 return NULL; 597 } 598 599 600 struct additional_rr_types 601 { 602 uint16_t rr_type; 603 rr_section_type rr_section; 604 }; 605 606 struct additional_rr_types default_additional_rr_types[] = { 607 { TYPE_A, ADDITIONAL_A_SECTION }, 608 { TYPE_AAAA, ADDITIONAL_AAAA_SECTION }, 609 { 0, (rr_section_type) 0 } 610 }; 611 612 struct additional_rr_types swap_aaaa_additional_rr_types[] = { 613 { TYPE_AAAA, ADDITIONAL_A_SECTION }, 614 { TYPE_A, ADDITIONAL_AAAA_SECTION }, 615 { 0, (rr_section_type) 0 } 616 }; 617 618 struct additional_rr_types rt_additional_rr_types[] = { 619 { TYPE_A, ADDITIONAL_A_SECTION }, 620 { TYPE_AAAA, ADDITIONAL_AAAA_SECTION }, 621 { TYPE_X25, ADDITIONAL_OTHER_SECTION }, 622 { TYPE_ISDN, ADDITIONAL_OTHER_SECTION }, 623 { 0, (rr_section_type) 0 } 624 }; 625 626 static void 627 add_additional_rrsets(struct query *query, answer_type *answer, 628 rrset_type *master_rrset, size_t rdata_index, 629 int allow_glue, struct additional_rr_types types[]) 630 { 631 size_t i; 632 633 assert(query); 634 assert(answer); 635 assert(master_rrset); 636 assert(rdata_atom_is_domain(rrset_rrtype(master_rrset), rdata_index)); 637 638 for (i = 0; i < master_rrset->rr_count; ++i) { 639 int j; 640 domain_type *additional = rdata_atom_domain(master_rrset->rrs[i].rdatas[rdata_index]); 641 domain_type *match = additional; 642 643 assert(additional); 644 645 if (!allow_glue && domain_is_glue(match, query->zone)) 646 continue; 647 648 /* 649 * Check to see if we need to generate the dependent 650 * based on a wildcard domain. 651 */ 652 while (!match->is_existing) { 653 match = match->parent; 654 } 655 if (additional != match && domain_wildcard_child(match)) { 656 domain_type *wildcard_child = domain_wildcard_child(match); 657 domain_type *temp = (domain_type *) region_alloc( 658 query->region, sizeof(domain_type)); 659 temp->rnode = NULL; 660 temp->dname = additional->dname; 661 temp->number = additional->number; 662 temp->parent = match; 663 temp->wildcard_child_closest_match = temp; 664 temp->rrsets = wildcard_child->rrsets; 665 temp->is_existing = wildcard_child->is_existing; 666 additional = temp; 667 } 668 669 for (j = 0; types[j].rr_type != 0; ++j) { 670 rrset_type *rrset = domain_find_rrset( 671 additional, query->zone, types[j].rr_type); 672 if (rrset) { 673 answer_add_rrset(answer, types[j].rr_section, 674 additional, rrset); 675 } 676 } 677 } 678 } 679 680 static int 681 answer_needs_ns(struct query* query) 682 { 683 assert(query); 684 /* Currently, only troublesome for DNSKEY and DS, 685 * cuz their RRSETs are quite large. */ 686 return (query->qtype != TYPE_DNSKEY && query->qtype != TYPE_DS); 687 } 688 689 static int 690 add_rrset(struct query *query, 691 answer_type *answer, 692 rr_section_type section, 693 domain_type *owner, 694 rrset_type *rrset) 695 { 696 int result; 697 698 assert(query); 699 assert(answer); 700 assert(owner); 701 assert(rrset); 702 assert(rrset_rrclass(rrset) == CLASS_IN); 703 704 result = answer_add_rrset(answer, section, owner, rrset); 705 switch (rrset_rrtype(rrset)) { 706 case TYPE_NS: 707 /* if query over IPv6, swap A and AAAA; put AAAA first */ 708 add_additional_rrsets(query, answer, rrset, 0, 1, 709 (query->addr.ss_family == AF_INET6)? 710 swap_aaaa_additional_rr_types: 711 default_additional_rr_types); 712 break; 713 case TYPE_MB: 714 add_additional_rrsets(query, answer, rrset, 0, 0, 715 default_additional_rr_types); 716 break; 717 case TYPE_MX: 718 case TYPE_KX: 719 add_additional_rrsets(query, answer, rrset, 1, 0, 720 default_additional_rr_types); 721 break; 722 case TYPE_RT: 723 add_additional_rrsets(query, answer, rrset, 1, 0, 724 rt_additional_rr_types); 725 break; 726 default: 727 break; 728 } 729 730 return result; 731 } 732 733 734 /* returns 0 on error, or the domain number for to_name. 735 from_name is changes to to_name by the DNAME rr. 736 DNAME rr is from src to dest. 737 closest encloser encloses the to_name. */ 738 static size_t 739 query_synthesize_cname(struct query* q, struct answer* answer, const dname_type* from_name, 740 const dname_type* to_name, domain_type* src, domain_type* to_closest_encloser, 741 domain_type** to_closest_match, uint32_t ttl) 742 { 743 /* add temporary domains for from_name and to_name and all 744 their (not allocated yet) parents */ 745 /* any domains below src are not_existing (because of DNAME at src) */ 746 int i; 747 domain_type* cname_domain; 748 domain_type* cname_dest; 749 rrset_type* rrset; 750 751 /* allocate source part */ 752 domain_type* lastparent = src; 753 assert(q && answer && from_name && to_name && src && to_closest_encloser); 754 assert(to_closest_match); 755 for(i=0; i < from_name->label_count - domain_dname(src)->label_count; i++) 756 { 757 domain_type* newdom = query_get_tempdomain(q); 758 if(!newdom) 759 return 0; 760 newdom->is_existing = 1; 761 newdom->parent = lastparent; 762 newdom->dname 763 = dname_partial_copy(q->region, 764 from_name, domain_dname(src)->label_count + i + 1); 765 if(dname_compare(domain_dname(newdom), q->qname) == 0) { 766 /* 0 good for query name, otherwise new number */ 767 newdom->number = 0; 768 } 769 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "created temp domain src %d. %s nr %d", i, 770 domain_to_string(newdom), (int)newdom->number)); 771 lastparent = newdom; 772 } 773 cname_domain = lastparent; 774 775 /* allocate dest part */ 776 lastparent = to_closest_encloser; 777 for(i=0; i < to_name->label_count - domain_dname(to_closest_encloser)->label_count; 778 i++) 779 { 780 domain_type* newdom = query_get_tempdomain(q); 781 if(!newdom) 782 return 0; 783 newdom->is_existing = 0; 784 newdom->parent = lastparent; 785 newdom->dname 786 = dname_partial_copy(q->region, 787 to_name, domain_dname(to_closest_encloser)->label_count + i + 1); 788 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "created temp domain dest %d. %s nr %d", i, 789 domain_to_string(newdom), (int)newdom->number)); 790 lastparent = newdom; 791 } 792 cname_dest = lastparent; 793 *to_closest_match = cname_dest; 794 795 /* allocate the CNAME RR */ 796 rrset = (rrset_type*) region_alloc(q->region, sizeof(rrset_type)); 797 memset(rrset, 0, sizeof(rrset_type)); 798 rrset->zone = q->zone; 799 rrset->rr_count = 1; 800 rrset->rrs = (rr_type*) region_alloc(q->region, sizeof(rr_type)); 801 memset(rrset->rrs, 0, sizeof(rr_type)); 802 rrset->rrs->owner = cname_domain; 803 rrset->rrs->ttl = ttl; 804 rrset->rrs->type = TYPE_CNAME; 805 rrset->rrs->klass = CLASS_IN; 806 rrset->rrs->rdata_count = 1; 807 rrset->rrs->rdatas = (rdata_atom_type*)region_alloc(q->region, 808 sizeof(rdata_atom_type)); 809 rrset->rrs->rdatas->domain = cname_dest; 810 811 if(!add_rrset(q, answer, ANSWER_SECTION, cname_domain, rrset)) { 812 log_msg(LOG_ERR, "could not add synthesized CNAME rrset to packet"); 813 } 814 815 return cname_dest->number; 816 } 817 818 /* 819 * Answer delegation information. 820 * 821 * DNSSEC: Include the DS RRset if present. Otherwise include an NSEC 822 * record proving the DS RRset does not exist. 823 */ 824 static void 825 answer_delegation(query_type *query, answer_type *answer) 826 { 827 assert(answer); 828 assert(query->delegation_domain); 829 assert(query->delegation_rrset); 830 831 if (query->cname_count == 0) { 832 AA_CLR(query->packet); 833 } else { 834 AA_SET(query->packet); 835 } 836 837 add_rrset(query, 838 answer, 839 AUTHORITY_SECTION, 840 query->delegation_domain, 841 query->delegation_rrset); 842 if (query->edns.dnssec_ok && zone_is_secure(query->zone)) { 843 rrset_type *rrset; 844 if ((rrset = domain_find_rrset(query->delegation_domain, query->zone, TYPE_DS))) { 845 add_rrset(query, answer, AUTHORITY_SECTION, 846 query->delegation_domain, rrset); 847 #ifdef NSEC3 848 } else if (query->zone->nsec3_param) { 849 nsec3_answer_delegation(query, answer); 850 #endif 851 } else if ((rrset = domain_find_rrset(query->delegation_domain, query->zone, TYPE_NSEC))) { 852 add_rrset(query, answer, AUTHORITY_SECTION, 853 query->delegation_domain, rrset); 854 } 855 } 856 } 857 858 859 /* 860 * Answer SOA information. 861 */ 862 static void 863 answer_soa(struct query *query, answer_type *answer) 864 { 865 if (query->qclass != CLASS_ANY) { 866 add_rrset(query, answer, 867 AUTHORITY_SECTION, 868 query->zone->apex, 869 query->zone->soa_nx_rrset); 870 } 871 } 872 873 874 /* 875 * Answer that the domain name exists but there is no RRset with the 876 * requested type. 877 * 878 * DNSSEC: Include the correct NSEC record proving that the type does 879 * not exist. In the wildcard no data (3.1.3.4) case the wildcard IS 880 * NOT expanded, so the ORIGINAL parameter must point to the original 881 * wildcard entry, not to the generated entry. 882 */ 883 static void 884 answer_nodata(struct query *query, answer_type *answer, domain_type *original) 885 { 886 if (query->cname_count == 0) { 887 answer_soa(query, answer); 888 } 889 890 #ifdef NSEC3 891 if (query->edns.dnssec_ok && query->zone->nsec3_param) { 892 nsec3_answer_nodata(query, answer, original); 893 } else 894 #endif 895 if (query->edns.dnssec_ok && zone_is_secure(query->zone)) { 896 domain_type *nsec_domain; 897 rrset_type *nsec_rrset; 898 899 nsec_domain = find_covering_nsec(original, query->zone, &nsec_rrset); 900 if (nsec_domain) { 901 add_rrset(query, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset); 902 } 903 } 904 } 905 906 static void 907 answer_nxdomain(query_type *query, answer_type *answer) 908 { 909 RCODE_SET(query->packet, RCODE_NXDOMAIN); 910 answer_soa(query, answer); 911 } 912 913 914 /* 915 * Answer domain information (or SOA if we do not have an RRset for 916 * the type specified by the query). 917 */ 918 static void 919 answer_domain(struct nsd* nsd, struct query *q, answer_type *answer, 920 domain_type *domain, domain_type *original) 921 { 922 rrset_type *rrset; 923 924 if (q->qtype == TYPE_ANY) { 925 int added = 0; 926 for (rrset = domain_find_any_rrset(domain, q->zone); rrset; rrset = rrset->next) { 927 if (rrset->zone == q->zone 928 #ifdef NSEC3 929 && rrset_rrtype(rrset) != TYPE_NSEC3 930 #endif 931 /* 932 * Don't include the RRSIG RRset when 933 * DNSSEC is used, because it is added 934 * automatically on an per-RRset basis. 935 */ 936 && !(q->edns.dnssec_ok 937 && zone_is_secure(q->zone) 938 && rrset_rrtype(rrset) == TYPE_RRSIG)) 939 { 940 add_rrset(q, answer, ANSWER_SECTION, domain, rrset); 941 ++added; 942 } 943 } 944 if (added == 0) { 945 answer_nodata(q, answer, original); 946 return; 947 } 948 #ifdef NSEC3 949 } else if (q->qtype == TYPE_NSEC3) { 950 answer_nodata(q, answer, original); 951 return; 952 #endif 953 } else if ((rrset = domain_find_rrset(domain, q->zone, q->qtype))) { 954 add_rrset(q, answer, ANSWER_SECTION, domain, rrset); 955 } else if ((rrset = domain_find_rrset(domain, q->zone, TYPE_CNAME))) { 956 int added; 957 958 /* 959 * If the CNAME is not added it is already in the 960 * answer, so we have a CNAME loop. Don't follow the 961 * CNAME target in this case. 962 */ 963 added = add_rrset(q, answer, ANSWER_SECTION, domain, rrset); 964 assert(rrset->rr_count > 0); 965 if (added) { 966 /* only process first CNAME record */ 967 domain_type *closest_match = rdata_atom_domain(rrset->rrs[0].rdatas[0]); 968 domain_type *closest_encloser = closest_match; 969 zone_type* origzone = q->zone; 970 ++q->cname_count; 971 972 answer_lookup_zone(nsd, q, answer, closest_match->number, 973 closest_match == closest_encloser, 974 closest_match, closest_encloser, 975 domain_dname(closest_match)); 976 q->zone = origzone; 977 } 978 return; 979 } else { 980 answer_nodata(q, answer, original); 981 return; 982 } 983 984 if (q->qclass != CLASS_ANY && q->zone->ns_rrset && answer_needs_ns(q)) { 985 add_rrset(q, answer, OPTIONAL_AUTHORITY_SECTION, q->zone->apex, 986 q->zone->ns_rrset); 987 } 988 } 989 990 991 /* 992 * Answer with authoritative data. If a wildcard is matched the owner 993 * name will be expanded to the domain name specified by 994 * DOMAIN_NUMBER. DOMAIN_NUMBER 0 (zero) is reserved for the original 995 * query name. 996 * 997 * DNSSEC: Include the necessary NSEC records in case the request 998 * domain name does not exist and/or a wildcard match does not exist. 999 */ 1000 static void 1001 answer_authoritative(struct nsd *nsd, 1002 struct query *q, 1003 answer_type *answer, 1004 size_t domain_number, 1005 int exact, 1006 domain_type *closest_match, 1007 domain_type *closest_encloser, 1008 const dname_type *qname) 1009 { 1010 domain_type *match; 1011 domain_type *original = closest_match; 1012 domain_type *dname_ce; 1013 rrset_type *rrset; 1014 1015 #ifdef NSEC3 1016 if(exact && domain_has_only_NSEC3(closest_match, q->zone)) { 1017 exact = 0; /* pretend it does not exist */ 1018 if(closest_encloser->parent) 1019 closest_encloser = closest_encloser->parent; 1020 } 1021 #endif /* NSEC3 */ 1022 if((dname_ce = find_dname_above(closest_encloser, q->zone)) != NULL) { 1023 /* occlude the found data, the DNAME is closest_encloser */ 1024 closest_encloser = dname_ce; 1025 exact = 0; 1026 } 1027 1028 if (exact) { 1029 match = closest_match; 1030 } else if ((rrset=domain_find_rrset(closest_encloser, q->zone, TYPE_DNAME))) { 1031 /* process DNAME */ 1032 const dname_type* name = qname; 1033 domain_type *dest = rdata_atom_domain(rrset->rrs[0].rdatas[0]); 1034 int added; 1035 assert(rrset->rr_count > 0); 1036 if(domain_number != 0) /* we followed CNAMEs or DNAMEs */ 1037 name = domain_dname(closest_match); 1038 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "expanding DNAME for q=%s", dname_to_string(name, NULL))); 1039 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->src is %s", 1040 domain_to_string(closest_encloser))); 1041 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->dest is %s", 1042 domain_to_string(dest))); 1043 /* if the DNAME set is not added we have a loop, do not follow */ 1044 added = add_rrset(q, answer, ANSWER_SECTION, closest_encloser, rrset); 1045 if(added) { 1046 domain_type* src = closest_encloser; 1047 const dname_type* newname = dname_replace(q->region, name, 1048 domain_dname(src), domain_dname(dest)); 1049 size_t newnum = 0; 1050 zone_type* origzone = q->zone; 1051 ++q->cname_count; 1052 if(!newname) { /* newname too long */ 1053 RCODE_SET(q->packet, RCODE_YXDOMAIN); 1054 return; 1055 } 1056 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->result is %s", dname_to_string(newname, NULL))); 1057 /* follow the DNAME */ 1058 exact = namedb_lookup(nsd->db, newname, &closest_match, &closest_encloser); 1059 /* synthesize CNAME record */ 1060 newnum = query_synthesize_cname(q, answer, name, newname, 1061 src, closest_encloser, &closest_match, rrset->rrs[0].ttl); 1062 if(!newnum) { 1063 /* could not synthesize the CNAME. */ 1064 /* return previous CNAMEs to make resolver recurse for us */ 1065 return; 1066 } 1067 1068 answer_lookup_zone(nsd, q, answer, newnum, 1069 closest_match == closest_encloser, 1070 closest_match, closest_encloser, newname); 1071 q->zone = origzone; 1072 } 1073 if(!added) /* log the error so operator can find looping recursors */ 1074 log_msg(LOG_INFO, "DNAME processing stopped due to loop, qname %s", 1075 dname_to_string(q->qname, NULL)); 1076 return; 1077 } else if (domain_wildcard_child(closest_encloser)) { 1078 /* Generate the domain from the wildcard. */ 1079 domain_type *wildcard_child = domain_wildcard_child(closest_encloser); 1080 #ifdef RATELIMIT 1081 q->wildcard_domain = wildcard_child; 1082 #endif 1083 1084 match = (domain_type *) region_alloc(q->region, 1085 sizeof(domain_type)); 1086 match->rnode = NULL; 1087 match->dname = wildcard_child->dname; 1088 match->parent = closest_encloser; 1089 match->wildcard_child_closest_match = match; 1090 match->number = domain_number; 1091 match->rrsets = wildcard_child->rrsets; 1092 match->is_existing = wildcard_child->is_existing; 1093 #ifdef NSEC3 1094 match->nsec3 = wildcard_child->nsec3; 1095 /* copy over these entries: 1096 match->nsec3_is_exact = wildcard_child->nsec3_is_exact; 1097 match->nsec3_cover = wildcard_child->nsec3_cover; 1098 match->nsec3_wcard_child_cover = wildcard_child->nsec3_wcard_child_cover; 1099 match->nsec3_ds_parent_is_exact = wildcard_child->nsec3_ds_parent_is_exact; 1100 match->nsec3_ds_parent_cover = wildcard_child->nsec3_ds_parent_cover; 1101 */ 1102 1103 if (q->edns.dnssec_ok && q->zone->nsec3_param) { 1104 /* Only add nsec3 wildcard data when do bit is set */ 1105 nsec3_answer_wildcard(q, answer, wildcard_child, qname); 1106 } 1107 #endif 1108 1109 /* 1110 * Remember the original domain in case a Wildcard No 1111 * Data (3.1.3.4) response needs to be generated. In 1112 * this particular case the wildcard IS NOT 1113 * expanded. 1114 */ 1115 original = wildcard_child; 1116 } else { 1117 match = NULL; 1118 } 1119 1120 /* Authoritative zone. */ 1121 #ifdef NSEC3 1122 if (q->edns.dnssec_ok && q->zone->nsec3_param) { 1123 nsec3_answer_authoritative(&match, q, answer, 1124 closest_encloser, qname); 1125 } else 1126 #endif 1127 if (q->edns.dnssec_ok && zone_is_secure(q->zone)) { 1128 if (match != closest_encloser) { 1129 domain_type *nsec_domain; 1130 rrset_type *nsec_rrset; 1131 1132 /* 1133 * No match found or generated from wildcard, 1134 * include NSEC record. 1135 */ 1136 nsec_domain = find_covering_nsec(closest_match, q->zone, &nsec_rrset); 1137 if (nsec_domain) { 1138 add_rrset(q, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset); 1139 } 1140 } 1141 if (!match) { 1142 domain_type *nsec_domain; 1143 rrset_type *nsec_rrset; 1144 1145 /* 1146 * No match and no wildcard. Include NSEC 1147 * proving there is no wildcard. 1148 */ 1149 nsec_domain = find_covering_nsec(closest_encloser->wildcard_child_closest_match, q->zone, &nsec_rrset); 1150 if (nsec_domain) { 1151 add_rrset(q, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset); 1152 } 1153 } 1154 } 1155 1156 #ifdef NSEC3 1157 if (RCODE(q->packet)!=RCODE_OK) { 1158 return; /* nsec3 collision failure */ 1159 } 1160 #endif 1161 if (match) { 1162 answer_domain(nsd, q, answer, match, original); 1163 } else { 1164 answer_nxdomain(q, answer); 1165 } 1166 } 1167 1168 /* 1169 * qname may be different after CNAMEs have been followed from query->qname. 1170 */ 1171 static void 1172 answer_lookup_zone(struct nsd *nsd, struct query *q, answer_type *answer, 1173 size_t domain_number, int exact, domain_type *closest_match, 1174 domain_type *closest_encloser, const dname_type *qname) 1175 { 1176 q->zone = domain_find_zone(nsd->db, closest_encloser); 1177 if (!q->zone) { 1178 /* no zone for this */ 1179 if(q->cname_count == 0) 1180 RCODE_SET(q->packet, RCODE_REFUSE); 1181 return; 1182 } 1183 if(!q->zone->apex || !q->zone->soa_rrset) { 1184 /* zone is configured but not loaded */ 1185 if(q->cname_count == 0) 1186 RCODE_SET(q->packet, RCODE_SERVFAIL); 1187 return; 1188 } 1189 /* now move up the closest encloser until it exists, previous 1190 * (possibly empty) closest encloser was useful to finding the zone 1191 * (for empty zones too), but now we want actual data nodes */ 1192 if (closest_encloser && !closest_encloser->is_existing) { 1193 exact = 0; 1194 while (closest_encloser != NULL && !closest_encloser->is_existing) 1195 closest_encloser = closest_encloser->parent; 1196 } 1197 1198 /* 1199 * See RFC 4035 (DNSSEC protocol) section 3.1.4.1 Responding 1200 * to Queries for DS RRs. 1201 */ 1202 if (exact && q->qtype == TYPE_DS && closest_encloser == q->zone->apex) { 1203 /* 1204 * Type DS query at a zone cut, use the responsible 1205 * parent zone to generate the answer if we are 1206 * authoritative for the parent zone. 1207 */ 1208 zone_type *zone = domain_find_parent_zone(q->zone); 1209 if (zone) 1210 q->zone = zone; 1211 } 1212 1213 /* see if the zone has expired (for secondary zones) */ 1214 if(q->zone && q->zone->opts && q->zone->opts->pattern && 1215 q->zone->opts->pattern->request_xfr != 0 && !q->zone->is_ok) { 1216 if(q->cname_count == 0) 1217 RCODE_SET(q->packet, RCODE_SERVFAIL); 1218 return; 1219 } 1220 1221 if (exact && q->qtype == TYPE_DS && closest_encloser == q->zone->apex) { 1222 /* 1223 * Type DS query at the zone apex (and the server is 1224 * not authoritative for the parent zone). 1225 */ 1226 if (q->qclass == CLASS_ANY) { 1227 AA_CLR(q->packet); 1228 } else { 1229 AA_SET(q->packet); 1230 } 1231 answer_nodata(q, answer, closest_encloser); 1232 } else { 1233 q->delegation_domain = domain_find_ns_rrsets( 1234 closest_encloser, q->zone, &q->delegation_rrset); 1235 if(q->delegation_domain && find_dname_above(q->delegation_domain, q->zone)) { 1236 q->delegation_domain = NULL; /* use higher DNAME */ 1237 } 1238 1239 if (!q->delegation_domain 1240 || (exact && q->qtype == TYPE_DS && closest_encloser == q->delegation_domain)) 1241 { 1242 if (q->qclass == CLASS_ANY) { 1243 AA_CLR(q->packet); 1244 } else { 1245 AA_SET(q->packet); 1246 } 1247 answer_authoritative(nsd, q, answer, domain_number, exact, 1248 closest_match, closest_encloser, qname); 1249 } 1250 else { 1251 answer_delegation(q, answer); 1252 } 1253 } 1254 } 1255 1256 static void 1257 answer_query(struct nsd *nsd, struct query *q) 1258 { 1259 domain_type *closest_match; 1260 domain_type *closest_encloser; 1261 int exact; 1262 uint16_t offset; 1263 answer_type answer; 1264 1265 answer_init(&answer); 1266 1267 exact = namedb_lookup(nsd->db, q->qname, &closest_match, &closest_encloser); 1268 1269 answer_lookup_zone(nsd, q, &answer, 0, exact, closest_match, 1270 closest_encloser, q->qname); 1271 ZTATUP2(nsd, q->zone, opcode, q->opcode); 1272 ZTATUP2(nsd, q->zone, qtype, q->qtype); 1273 ZTATUP2(nsd, q->zone, qclass, q->qclass); 1274 1275 offset = dname_label_offsets(q->qname)[domain_dname(closest_encloser)->label_count - 1] + QHEADERSZ; 1276 query_add_compression_domain(q, closest_encloser, offset); 1277 encode_answer(q, &answer); 1278 query_clear_compression_tables(q); 1279 } 1280 1281 void 1282 query_prepare_response(query_type *q, nsd_type *nsd) 1283 { 1284 uint16_t flags; 1285 1286 /* 1287 * Preserve the data up-to the current packet's limit. 1288 */ 1289 buffer_set_position(q->packet, buffer_limit(q->packet)); 1290 buffer_set_limit(q->packet, buffer_capacity(q->packet)); 1291 1292 /* 1293 * Reserve space for the EDNS records if required. 1294 */ 1295 q->reserved_space = edns_reserved_space(&q->edns); 1296 q->reserved_space += tsig_reserved_space(&q->tsig); 1297 if(q->edns.nsid == 1 && nsd->nsid_len > 0 && 1298 q->edns.status != EDNS_NOT_PRESENT) 1299 q->reserved_space += OPT_HDR + nsd->nsid_len; 1300 1301 /* Update the flags. */ 1302 flags = FLAGS(q->packet); 1303 flags &= 0x0100U; /* Preserve the RD flag. */ 1304 /* CD flag must be cleared for auth answers */ 1305 flags |= 0x8000U; /* Set the QR flag. */ 1306 FLAGS_SET(q->packet, flags); 1307 } 1308 1309 /* 1310 * Processes the query. 1311 * 1312 */ 1313 query_state_type 1314 query_process(query_type *q, nsd_type *nsd) 1315 { 1316 /* The query... */ 1317 nsd_rc_type rc; 1318 query_state_type query_state; 1319 uint16_t arcount; 1320 1321 /* Sanity checks */ 1322 if (buffer_limit(q->packet) < QHEADERSZ) { 1323 /* packet too small to contain DNS header. 1324 Now packet investigation macros will work without problems. */ 1325 return QUERY_DISCARDED; 1326 } 1327 if (QR(q->packet)) { 1328 /* Not a query? Drop it on the floor. */ 1329 return QUERY_DISCARDED; 1330 } 1331 1332 /* check opcode early on, because new opcodes may have different 1333 * specification of the meaning of the rest of the packet */ 1334 q->opcode = OPCODE(q->packet); 1335 if(q->opcode != OPCODE_QUERY && q->opcode != OPCODE_NOTIFY) { 1336 if(query_ratelimit_err(nsd)) 1337 return QUERY_DISCARDED; 1338 return query_error(q, NSD_RC_IMPL); 1339 } 1340 1341 if (RCODE(q->packet) != RCODE_OK || !process_query_section(q)) { 1342 return query_formerr(q, nsd); 1343 } 1344 1345 /* Update statistics. */ 1346 STATUP2(nsd, opcode, q->opcode); 1347 STATUP2(nsd, qtype, q->qtype); 1348 STATUP2(nsd, qclass, q->qclass); 1349 1350 if (q->opcode != OPCODE_QUERY) { 1351 if (q->opcode == OPCODE_NOTIFY) { 1352 return answer_notify(nsd, q); 1353 } else { 1354 if(query_ratelimit_err(nsd)) 1355 return QUERY_DISCARDED; 1356 return query_error(q, NSD_RC_IMPL); 1357 } 1358 } 1359 1360 /* Dont bother to answer more than one question at once... */ 1361 if (QDCOUNT(q->packet) != 1) { 1362 FLAGS_SET(q->packet, 0); 1363 return query_formerr(q, nsd); 1364 } 1365 /* Ignore settings of flags */ 1366 1367 /* Dont allow any records in the answer or authority section... 1368 except for IXFR queries. */ 1369 if (ANCOUNT(q->packet) != 0 || 1370 (q->qtype!=TYPE_IXFR && NSCOUNT(q->packet) != 0)) { 1371 return query_formerr(q, nsd); 1372 } 1373 if(q->qtype==TYPE_IXFR && NSCOUNT(q->packet) > 0) { 1374 int i; /* skip ixfr soa information data here */ 1375 for(i=0; i< NSCOUNT(q->packet); i++) 1376 if(!packet_skip_rr(q->packet, 0)) 1377 return query_formerr(q, nsd); 1378 } 1379 1380 arcount = ARCOUNT(q->packet); 1381 if (arcount > 0) { 1382 /* According to draft-ietf-dnsext-rfc2671bis-edns0-10: 1383 * "The placement flexibility for the OPT RR does not 1384 * override the need for the TSIG or SIG(0) RRs to be 1385 * the last in the additional section whenever they are 1386 * present." 1387 * So we should not have to check for TSIG RR before 1388 * OPT RR. Keep the code for backwards compatibility. 1389 */ 1390 1391 /* see if tsig is before edns record */ 1392 if (!tsig_parse_rr(&q->tsig, q->packet)) 1393 return query_formerr(q, nsd); 1394 if(q->tsig.status != TSIG_NOT_PRESENT) 1395 --arcount; 1396 } 1397 /* See if there is an OPT RR. */ 1398 if (arcount > 0) { 1399 if (edns_parse_record(&q->edns, q->packet)) 1400 --arcount; 1401 } 1402 /* See if there is a TSIG RR. */ 1403 if (arcount > 0 && q->tsig.status == TSIG_NOT_PRESENT) { 1404 /* see if tsig is after the edns record */ 1405 if (!tsig_parse_rr(&q->tsig, q->packet)) 1406 return query_formerr(q, nsd); 1407 if(q->tsig.status != TSIG_NOT_PRESENT) 1408 --arcount; 1409 } 1410 /* If more RRs left in Add. Section, FORMERR. */ 1411 if (arcount > 0) { 1412 return query_formerr(q, nsd); 1413 } 1414 1415 /* Do we have any trailing garbage? */ 1416 #ifdef STRICT_MESSAGE_PARSE 1417 if (buffer_remaining(q->packet) > 0) { 1418 /* If we're strict.... */ 1419 return query_formerr(q, nsd); 1420 } 1421 #endif 1422 /* Remove trailing garbage. */ 1423 buffer_set_limit(q->packet, buffer_position(q->packet)); 1424 1425 rc = process_tsig(q); 1426 if (rc != NSD_RC_OK) { 1427 return query_error(q, rc); 1428 } 1429 rc = process_edns(nsd, q); 1430 if (rc != NSD_RC_OK) { 1431 /* We should not return FORMERR, but BADVERS (=16). 1432 * BADVERS is created with Ext. RCODE, followed by RCODE. 1433 * Ext. RCODE is set to 1, RCODE must be 0 (getting 0x10 = 16). 1434 * Thus RCODE = NOERROR = NSD_RC_OK. */ 1435 return query_error(q, NSD_RC_OK); 1436 } 1437 1438 query_prepare_response(q, nsd); 1439 1440 if (q->qclass != CLASS_IN && q->qclass != CLASS_ANY) { 1441 if (q->qclass == CLASS_CH) { 1442 return answer_chaos(nsd, q); 1443 } else { 1444 return query_error(q, NSD_RC_REFUSE); 1445 } 1446 } 1447 1448 query_state = answer_axfr_ixfr(nsd, q); 1449 if (query_state == QUERY_PROCESSED || query_state == QUERY_IN_AXFR) { 1450 return query_state; 1451 } 1452 1453 answer_query(nsd, q); 1454 1455 return QUERY_PROCESSED; 1456 } 1457 1458 void 1459 query_add_optional(query_type *q, nsd_type *nsd) 1460 { 1461 struct edns_data *edns = &nsd->edns_ipv4; 1462 #if defined(INET6) 1463 if (q->addr.ss_family == AF_INET6) { 1464 edns = &nsd->edns_ipv6; 1465 } 1466 #endif 1467 if (RCODE(q->packet) == RCODE_FORMAT) { 1468 return; 1469 } 1470 switch (q->edns.status) { 1471 case EDNS_NOT_PRESENT: 1472 break; 1473 case EDNS_OK: 1474 if (q->edns.dnssec_ok) edns->ok[7] = 0x80; 1475 else edns->ok[7] = 0x00; 1476 buffer_write(q->packet, edns->ok, OPT_LEN); 1477 if (nsd->nsid_len > 0 && q->edns.nsid == 1 && buffer_available( 1478 q->packet, OPT_RDATA+OPT_HDR+nsd->nsid_len)) { 1479 /* rdata length */ 1480 buffer_write(q->packet, edns->rdata_nsid, OPT_RDATA); 1481 /* nsid opt header */ 1482 buffer_write(q->packet, edns->nsid, OPT_HDR); 1483 /* nsid payload */ 1484 buffer_write(q->packet, nsd->nsid, nsd->nsid_len); 1485 } else { 1486 /* fill with NULLs */ 1487 buffer_write(q->packet, edns->rdata_none, OPT_RDATA); 1488 } 1489 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1); 1490 STATUP(nsd, edns); 1491 ZTATUP(nsd, q->zone, edns); 1492 break; 1493 case EDNS_ERROR: 1494 if (q->edns.dnssec_ok) edns->error[7] = 0x80; 1495 else edns->error[7] = 0x00; 1496 buffer_write(q->packet, edns->error, OPT_LEN); 1497 buffer_write(q->packet, edns->rdata_none, OPT_RDATA); 1498 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1); 1499 STATUP(nsd, ednserr); 1500 ZTATUP(nsd, q->zone, ednserr); 1501 break; 1502 } 1503 1504 if (q->tsig.status != TSIG_NOT_PRESENT) { 1505 if (q->tsig.status == TSIG_ERROR || 1506 q->tsig.error_code != TSIG_ERROR_NOERROR) { 1507 tsig_error_reply(&q->tsig); 1508 tsig_append_rr(&q->tsig, q->packet); 1509 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1); 1510 } else if(q->tsig.status == TSIG_OK && 1511 q->tsig.error_code == TSIG_ERROR_NOERROR) 1512 { 1513 if(q->tsig_prepare_it) 1514 tsig_prepare(&q->tsig); 1515 if(q->tsig_update_it) 1516 tsig_update(&q->tsig, q->packet, buffer_position(q->packet)); 1517 if(q->tsig_sign_it) { 1518 tsig_sign(&q->tsig); 1519 tsig_append_rr(&q->tsig, q->packet); 1520 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1); 1521 } 1522 } 1523 } 1524 } 1525