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, domain_type **compressed_dnames) 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->compressed_dnames = compressed_dnames; 196 query->packet = buffer_create(region, QIOBUFSZ); 197 region_add_cleanup(region, query_cleanup, query); 198 query->compressed_dname_offsets_size = compressed_dname_size; 199 tsig_create_record(&query->tsig, region); 200 query->tsig_prepare_it = 1; 201 query->tsig_update_it = 1; 202 query->tsig_sign_it = 1; 203 return query; 204 } 205 206 void 207 query_reset(query_type *q, size_t maxlen, int is_tcp) 208 { 209 /* 210 * As long as less than 4Kb (region block size) has been used, 211 * this call to free_all is free, the block is saved for re-use, 212 * so no malloc() or free() calls are done. 213 * at present use of the region is for: 214 * o query qname dname_type (255 max). 215 * o wildcard expansion domain_type (7*ptr+u32+2bytes)+(5*ptr nsec3) 216 * o wildcard expansion for additional section domain_type. 217 * o nsec3 hashed name(s) (3 dnames for a nonexist_proof, 218 * one proof per wildcard and for nx domain). 219 */ 220 region_free_all(q->region); 221 q->addrlen = sizeof(q->addr); 222 q->maxlen = maxlen; 223 q->reserved_space = 0; 224 buffer_clear(q->packet); 225 edns_init_record(&q->edns); 226 tsig_init_record(&q->tsig, NULL, NULL); 227 q->tsig_prepare_it = 1; 228 q->tsig_update_it = 1; 229 q->tsig_sign_it = 1; 230 q->tcp = is_tcp; 231 q->qname = NULL; 232 q->qtype = 0; 233 q->qclass = 0; 234 q->zone = NULL; 235 q->opcode = 0; 236 q->cname_count = 0; 237 q->delegation_domain = NULL; 238 q->delegation_rrset = NULL; 239 q->compressed_dname_count = 0; 240 q->number_temporary_domains = 0; 241 242 q->axfr_is_done = 0; 243 q->axfr_zone = NULL; 244 q->axfr_current_domain = NULL; 245 q->axfr_current_rrset = NULL; 246 q->axfr_current_rr = 0; 247 248 #ifdef RATELIMIT 249 q->wildcard_domain = NULL; 250 #endif 251 } 252 253 /* get a temporary domain number (or 0=failure) */ 254 static domain_type* 255 query_get_tempdomain(struct query *q) 256 { 257 static domain_type d[EXTRA_DOMAIN_NUMBERS]; 258 if(q->number_temporary_domains >= EXTRA_DOMAIN_NUMBERS) 259 return 0; 260 q->number_temporary_domains ++; 261 memset(&d[q->number_temporary_domains-1], 0, sizeof(domain_type)); 262 d[q->number_temporary_domains-1].number = q->compressed_dname_offsets_size + 263 q->number_temporary_domains - 1; 264 return &d[q->number_temporary_domains-1]; 265 } 266 267 static void 268 query_addtxt(struct query *q, 269 const uint8_t *dname, 270 uint16_t klass, 271 uint32_t ttl, 272 const char *txt) 273 { 274 size_t txt_length = strlen(txt); 275 uint8_t len = (uint8_t) txt_length; 276 277 assert(txt_length <= UCHAR_MAX); 278 279 /* Add the dname */ 280 if (dname >= buffer_begin(q->packet) 281 && dname <= buffer_current(q->packet)) 282 { 283 buffer_write_u16(q->packet, 284 0xc000 | (dname - buffer_begin(q->packet))); 285 } else { 286 buffer_write(q->packet, dname + 1, *dname); 287 } 288 289 buffer_write_u16(q->packet, TYPE_TXT); 290 buffer_write_u16(q->packet, klass); 291 buffer_write_u32(q->packet, ttl); 292 buffer_write_u16(q->packet, len + 1); 293 buffer_write_u8(q->packet, len); 294 buffer_write(q->packet, txt, len); 295 } 296 297 /* 298 * Parse the question section of a query. The normalized query name 299 * is stored in QUERY->name, the class in QUERY->klass, and the type 300 * in QUERY->type. 301 */ 302 static int 303 process_query_section(query_type *query) 304 { 305 uint8_t qnamebuf[MAXDOMAINLEN]; 306 307 buffer_set_position(query->packet, QHEADERSZ); 308 /* Lets parse the query name and convert it to lower case. */ 309 if(!packet_read_query_section(query->packet, qnamebuf, 310 &query->qtype, &query->qclass)) 311 return 0; 312 query->qname = dname_make(query->region, qnamebuf, 1); 313 return 1; 314 } 315 316 317 /* 318 * Process an optional EDNS OPT record. Sets QUERY->EDNS to 0 if 319 * there was no EDNS record, to -1 if there was an invalid or 320 * unsupported EDNS record, and to 1 otherwise. Updates QUERY->MAXLEN 321 * if the EDNS record specifies a maximum supported response length. 322 * 323 * Return NSD_RC_FORMAT on failure, NSD_RC_OK on success. 324 */ 325 static nsd_rc_type 326 process_edns(nsd_type* nsd, struct query *q) 327 { 328 if (q->edns.status == EDNS_ERROR) { 329 /* The only error is VERSION not implemented */ 330 return NSD_RC_FORMAT; 331 } 332 333 if (q->edns.status == EDNS_OK) { 334 /* Only care about UDP size larger than normal... */ 335 if (!q->tcp && q->edns.maxlen > UDP_MAX_MESSAGE_LEN) { 336 size_t edns_size; 337 #if defined(INET6) 338 if (q->addr.ss_family == AF_INET6) { 339 edns_size = nsd->ipv6_edns_size; 340 } else 341 #endif 342 edns_size = nsd->ipv4_edns_size; 343 344 if (q->edns.maxlen < edns_size) { 345 q->maxlen = q->edns.maxlen; 346 } else { 347 q->maxlen = edns_size; 348 } 349 350 #if defined(INET6) && !defined(IPV6_USE_MIN_MTU) && !defined(IPV6_MTU) 351 /* 352 * Use IPv6 minimum MTU to avoid sending 353 * packets that are too large for some links. 354 * IPv6 will not automatically fragment in 355 * this case (unlike IPv4). 356 */ 357 if (q->addr.ss_family == AF_INET6 358 && q->maxlen > IPV6_MIN_MTU) 359 { 360 q->maxlen = IPV6_MIN_MTU; 361 } 362 #endif 363 } 364 365 /* Strip the OPT resource record off... */ 366 buffer_set_position(q->packet, q->edns.position); 367 buffer_set_limit(q->packet, q->edns.position); 368 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) - 1); 369 } 370 return NSD_RC_OK; 371 } 372 373 /* 374 * Processes TSIG. 375 * Sets error when tsig does not verify on the query. 376 */ 377 static nsd_rc_type 378 process_tsig(struct query* q) 379 { 380 if(q->tsig.status == TSIG_ERROR) 381 return NSD_RC_FORMAT; 382 if(q->tsig.status == TSIG_OK) { 383 if(!tsig_from_query(&q->tsig)) { 384 char a[128]; 385 addr2str(&q->addr, a, sizeof(a)); 386 log_msg(LOG_ERR, "query: bad tsig (%s) for key %s from %s", 387 tsig_error(q->tsig.error_code), 388 dname_to_string(q->tsig.key_name, NULL), a); 389 return NSD_RC_NOTAUTH; 390 } 391 buffer_set_limit(q->packet, q->tsig.position); 392 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) - 1); 393 tsig_prepare(&q->tsig); 394 tsig_update(&q->tsig, q->packet, buffer_limit(q->packet)); 395 if(!tsig_verify(&q->tsig)) { 396 char a[128]; 397 addr2str(&q->addr, a, sizeof(a)); 398 log_msg(LOG_ERR, "query: bad tsig signature for key %s from %s", 399 dname_to_string(q->tsig.key->name, NULL), a); 400 return NSD_RC_NOTAUTH; 401 } 402 DEBUG(DEBUG_XFRD,1, (LOG_INFO, "query good tsig signature for %s", 403 dname_to_string(q->tsig.key->name, NULL))); 404 } 405 return NSD_RC_OK; 406 } 407 408 /* 409 * Check notify acl and forward to xfrd (or return an error). 410 */ 411 static query_state_type 412 answer_notify(struct nsd* nsd, struct query *query) 413 { 414 int acl_num, acl_num_xfr; 415 struct acl_options *why; 416 nsd_rc_type rc; 417 418 struct zone_options* zone_opt; 419 DEBUG(DEBUG_XFRD,1, (LOG_INFO, "got notify %s processing acl", 420 dname_to_string(query->qname, NULL))); 421 422 zone_opt = zone_options_find(nsd->options, query->qname); 423 if(!zone_opt) 424 return query_error(query, NSD_RC_NXDOMAIN); 425 426 if(!nsd->this_child) /* we are in debug mode or something */ 427 return query_error(query, NSD_RC_SERVFAIL); 428 429 if(!tsig_find_rr(&query->tsig, query->packet)) { 430 DEBUG(DEBUG_XFRD,2, (LOG_ERR, "bad tsig RR format")); 431 return query_error(query, NSD_RC_FORMAT); 432 } 433 rc = process_tsig(query); 434 if(rc != NSD_RC_OK) 435 return query_error(query, rc); 436 437 /* check if it passes acl */ 438 if((acl_num = acl_check_incoming(zone_opt->pattern->allow_notify, query, 439 &why)) != -1) 440 { 441 sig_atomic_t mode = NSD_PASS_TO_XFRD; 442 int s = nsd->this_child->parent_fd; 443 uint16_t sz; 444 uint32_t acl_send = htonl(acl_num); 445 uint32_t acl_xfr; 446 size_t pos; 447 448 /* Find priority candidate for request XFR. -1 if no match */ 449 acl_num_xfr = acl_check_incoming( 450 zone_opt->pattern->request_xfr, query, NULL); 451 452 acl_xfr = htonl(acl_num_xfr); 453 454 assert(why); 455 DEBUG(DEBUG_XFRD,1, (LOG_INFO, "got notify %s passed acl %s %s", 456 dname_to_string(query->qname, NULL), 457 why->ip_address_spec, 458 why->nokey?"NOKEY": 459 (why->blocked?"BLOCKED":why->key_name))); 460 sz = buffer_limit(query->packet); 461 if(buffer_limit(query->packet) > MAX_PACKET_SIZE) 462 return query_error(query, NSD_RC_SERVFAIL); 463 /* forward to xfrd for processing 464 Note. Blocking IPC I/O, but acl is OK. */ 465 sz = htons(sz); 466 if(!write_socket(s, &mode, sizeof(mode)) || 467 !write_socket(s, &sz, sizeof(sz)) || 468 !write_socket(s, buffer_begin(query->packet), 469 buffer_limit(query->packet)) || 470 !write_socket(s, &acl_send, sizeof(acl_send)) || 471 !write_socket(s, &acl_xfr, sizeof(acl_xfr))) { 472 log_msg(LOG_ERR, "error in IPC notify server2main, %s", 473 strerror(errno)); 474 return query_error(query, NSD_RC_SERVFAIL); 475 } 476 if(verbosity >= 1) { 477 uint32_t serial = 0; 478 char address[128]; 479 addr2str(&query->addr, address, sizeof(address)); 480 if(packet_find_notify_serial(query->packet, &serial)) 481 VERBOSITY(1, (LOG_INFO, "notify for %s from %s serial %u", 482 dname_to_string(query->qname, NULL), address, 483 (unsigned)serial)); 484 else 485 VERBOSITY(1, (LOG_INFO, "notify for %s from %s", 486 dname_to_string(query->qname, NULL), address)); 487 } 488 489 /* create notify reply - keep same query contents */ 490 QR_SET(query->packet); /* This is an answer. */ 491 AA_SET(query->packet); /* we are authoritative. */ 492 ANCOUNT_SET(query->packet, 0); 493 NSCOUNT_SET(query->packet, 0); 494 ARCOUNT_SET(query->packet, 0); 495 RCODE_SET(query->packet, RCODE_OK); /* Error code. */ 496 /* position is right after the query */ 497 pos = buffer_position(query->packet); 498 buffer_clear(query->packet); 499 buffer_set_position(query->packet, pos); 500 /* tsig is added in add_additional later (if needed) */ 501 return QUERY_PROCESSED; 502 } 503 504 if (verbosity >= 2) { 505 char address[128]; 506 addr2str(&query->addr, address, sizeof(address)); 507 VERBOSITY(2, (LOG_INFO, "notify for %s from %s refused, %s%s", 508 dname_to_string(query->qname, NULL), 509 address, 510 why?why->key_name:"no acl matches", 511 why?why->ip_address_spec:".")); 512 } 513 514 return query_error(query, NSD_RC_REFUSE); 515 } 516 517 518 /* 519 * Answer a query in the CHAOS class. 520 */ 521 static query_state_type 522 answer_chaos(struct nsd *nsd, query_type *q) 523 { 524 AA_CLR(q->packet); 525 switch (q->qtype) { 526 case TYPE_ANY: 527 case TYPE_TXT: 528 if ((q->qname->name_size == 11 529 && memcmp(dname_name(q->qname), "\002id\006server", 11) == 0) || 530 (q->qname->name_size == 15 531 && memcmp(dname_name(q->qname), "\010hostname\004bind", 15) == 0)) 532 { 533 /* Add ID */ 534 query_addtxt(q, 535 buffer_begin(q->packet) + QHEADERSZ, 536 CLASS_CH, 537 0, 538 nsd->identity); 539 ANCOUNT_SET(q->packet, ANCOUNT(q->packet) + 1); 540 } else if ((q->qname->name_size == 16 541 && memcmp(dname_name(q->qname), "\007version\006server", 16) == 0) || 542 (q->qname->name_size == 14 543 && memcmp(dname_name(q->qname), "\007version\004bind", 14) == 0)) 544 { 545 if(!nsd->options->hide_version) { 546 /* Add version */ 547 query_addtxt(q, 548 buffer_begin(q->packet) + QHEADERSZ, 549 CLASS_CH, 550 0, 551 nsd->version); 552 ANCOUNT_SET(q->packet, ANCOUNT(q->packet) + 1); 553 } else { 554 RCODE_SET(q->packet, RCODE_REFUSE); 555 } 556 } else { 557 RCODE_SET(q->packet, RCODE_REFUSE); 558 } 559 break; 560 default: 561 RCODE_SET(q->packet, RCODE_REFUSE); 562 break; 563 } 564 565 return QUERY_PROCESSED; 566 } 567 568 569 /* 570 * Find the covering NSEC for a non-existent domain name. Normally 571 * the NSEC will be located at CLOSEST_MATCH, except when it is an 572 * empty non-terminal. In this case the NSEC may be located at the 573 * previous domain name (in canonical ordering). 574 */ 575 static domain_type * 576 find_covering_nsec(domain_type *closest_match, 577 zone_type *zone, 578 rrset_type **nsec_rrset) 579 { 580 assert(closest_match); 581 assert(nsec_rrset); 582 583 /* loop away temporary created domains. For real ones it is &RBTREE_NULL */ 584 #ifdef USE_RADIX_TREE 585 while (closest_match->rnode == NULL) 586 #else 587 while (closest_match->node.parent == NULL) 588 #endif 589 closest_match = closest_match->parent; 590 while (closest_match) { 591 *nsec_rrset = domain_find_rrset(closest_match, zone, TYPE_NSEC); 592 if (*nsec_rrset) { 593 return closest_match; 594 } 595 if (closest_match == zone->apex) { 596 /* Don't look outside the current zone. */ 597 return NULL; 598 } 599 closest_match = domain_previous(closest_match); 600 } 601 return NULL; 602 } 603 604 605 struct additional_rr_types 606 { 607 uint16_t rr_type; 608 rr_section_type rr_section; 609 }; 610 611 struct additional_rr_types default_additional_rr_types[] = { 612 { TYPE_A, ADDITIONAL_A_SECTION }, 613 { TYPE_AAAA, ADDITIONAL_AAAA_SECTION }, 614 { 0, (rr_section_type) 0 } 615 }; 616 617 struct additional_rr_types swap_aaaa_additional_rr_types[] = { 618 { TYPE_AAAA, ADDITIONAL_A_SECTION }, 619 { TYPE_A, ADDITIONAL_AAAA_SECTION }, 620 { 0, (rr_section_type) 0 } 621 }; 622 623 struct additional_rr_types rt_additional_rr_types[] = { 624 { TYPE_A, ADDITIONAL_A_SECTION }, 625 { TYPE_AAAA, ADDITIONAL_AAAA_SECTION }, 626 { TYPE_X25, ADDITIONAL_OTHER_SECTION }, 627 { TYPE_ISDN, ADDITIONAL_OTHER_SECTION }, 628 { 0, (rr_section_type) 0 } 629 }; 630 631 static void 632 add_additional_rrsets(struct query *query, answer_type *answer, 633 rrset_type *master_rrset, size_t rdata_index, 634 int allow_glue, struct additional_rr_types types[]) 635 { 636 size_t i; 637 638 assert(query); 639 assert(answer); 640 assert(master_rrset); 641 assert(rdata_atom_is_domain(rrset_rrtype(master_rrset), rdata_index)); 642 643 for (i = 0; i < master_rrset->rr_count; ++i) { 644 int j; 645 domain_type *additional = rdata_atom_domain(master_rrset->rrs[i].rdatas[rdata_index]); 646 domain_type *match = additional; 647 648 assert(additional); 649 650 if (!allow_glue && domain_is_glue(match, query->zone)) 651 continue; 652 653 /* 654 * Check to see if we need to generate the dependent 655 * based on a wildcard domain. 656 */ 657 while (!match->is_existing) { 658 match = match->parent; 659 } 660 if (additional != match && domain_wildcard_child(match)) { 661 domain_type *wildcard_child = domain_wildcard_child(match); 662 domain_type *temp = (domain_type *) region_alloc( 663 query->region, sizeof(domain_type)); 664 #ifdef USE_RADIX_TREE 665 temp->rnode = NULL; 666 temp->dname = additional->dname; 667 #else 668 memcpy(&temp->node, &additional->node, sizeof(rbnode_type)); 669 temp->node.parent = NULL; 670 #endif 671 temp->number = additional->number; 672 temp->parent = match; 673 temp->wildcard_child_closest_match = temp; 674 temp->rrsets = wildcard_child->rrsets; 675 temp->is_existing = wildcard_child->is_existing; 676 additional = temp; 677 } 678 679 for (j = 0; types[j].rr_type != 0; ++j) { 680 rrset_type *rrset = domain_find_rrset( 681 additional, query->zone, types[j].rr_type); 682 if (rrset) { 683 answer_add_rrset(answer, types[j].rr_section, 684 additional, rrset); 685 } 686 } 687 } 688 } 689 690 static int 691 answer_needs_ns(struct query* query) 692 { 693 assert(query); 694 /* Currently, only troublesome for DNSKEY and DS, 695 * cuz their RRSETs are quite large. */ 696 return (query->qtype != TYPE_DNSKEY && query->qtype != TYPE_DS); 697 } 698 699 static int 700 add_rrset(struct query *query, 701 answer_type *answer, 702 rr_section_type section, 703 domain_type *owner, 704 rrset_type *rrset) 705 { 706 int result; 707 708 assert(query); 709 assert(answer); 710 assert(owner); 711 assert(rrset); 712 assert(rrset_rrclass(rrset) == CLASS_IN); 713 714 result = answer_add_rrset(answer, section, owner, rrset); 715 if(minimal_responses && section != AUTHORITY_SECTION && 716 query->qtype != TYPE_NS) 717 return result; 718 switch (rrset_rrtype(rrset)) { 719 case TYPE_NS: 720 #if defined(INET6) 721 /* if query over IPv6, swap A and AAAA; put AAAA first */ 722 add_additional_rrsets(query, answer, rrset, 0, 1, 723 (query->addr.ss_family == AF_INET6)? 724 swap_aaaa_additional_rr_types: 725 default_additional_rr_types); 726 #else 727 add_additional_rrsets(query, answer, rrset, 0, 1, 728 default_additional_rr_types); 729 #endif 730 break; 731 case TYPE_MB: 732 add_additional_rrsets(query, answer, rrset, 0, 0, 733 default_additional_rr_types); 734 break; 735 case TYPE_MX: 736 case TYPE_KX: 737 add_additional_rrsets(query, answer, rrset, 1, 0, 738 default_additional_rr_types); 739 break; 740 case TYPE_RT: 741 add_additional_rrsets(query, answer, rrset, 1, 0, 742 rt_additional_rr_types); 743 break; 744 case TYPE_SRV: 745 add_additional_rrsets(query, answer, rrset, 3, 0, 746 default_additional_rr_types); 747 break; 748 default: 749 break; 750 } 751 752 return result; 753 } 754 755 756 /* returns 0 on error, or the domain number for to_name. 757 from_name is changes to to_name by the DNAME rr. 758 DNAME rr is from src to dest. 759 closest encloser encloses the to_name. */ 760 static size_t 761 query_synthesize_cname(struct query* q, struct answer* answer, const dname_type* from_name, 762 const dname_type* to_name, domain_type* src, domain_type* to_closest_encloser, 763 domain_type** to_closest_match, uint32_t ttl) 764 { 765 /* add temporary domains for from_name and to_name and all 766 their (not allocated yet) parents */ 767 /* any domains below src are not_existing (because of DNAME at src) */ 768 int i; 769 domain_type* cname_domain; 770 domain_type* cname_dest; 771 rrset_type* rrset; 772 773 /* allocate source part */ 774 domain_type* lastparent = src; 775 assert(q && answer && from_name && to_name && src && to_closest_encloser); 776 assert(to_closest_match); 777 for(i=0; i < from_name->label_count - domain_dname(src)->label_count; i++) 778 { 779 domain_type* newdom = query_get_tempdomain(q); 780 if(!newdom) 781 return 0; 782 newdom->is_existing = 1; 783 newdom->parent = lastparent; 784 #ifdef USE_RADIX_TREE 785 newdom->dname 786 #else 787 newdom->node.key 788 #endif 789 = dname_partial_copy(q->region, 790 from_name, domain_dname(src)->label_count + i + 1); 791 if(dname_compare(domain_dname(newdom), q->qname) == 0) { 792 /* 0 good for query name, otherwise new number */ 793 newdom->number = 0; 794 } 795 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "created temp domain src %d. %s nr %d", i, 796 domain_to_string(newdom), (int)newdom->number)); 797 lastparent = newdom; 798 } 799 cname_domain = lastparent; 800 801 /* allocate dest part */ 802 lastparent = to_closest_encloser; 803 for(i=0; i < to_name->label_count - domain_dname(to_closest_encloser)->label_count; 804 i++) 805 { 806 domain_type* newdom = query_get_tempdomain(q); 807 if(!newdom) 808 return 0; 809 newdom->is_existing = 0; 810 newdom->parent = lastparent; 811 #ifdef USE_RADIX_TREE 812 newdom->dname 813 #else 814 newdom->node.key 815 #endif 816 = dname_partial_copy(q->region, 817 to_name, domain_dname(to_closest_encloser)->label_count + i + 1); 818 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "created temp domain dest %d. %s nr %d", i, 819 domain_to_string(newdom), (int)newdom->number)); 820 lastparent = newdom; 821 } 822 cname_dest = lastparent; 823 *to_closest_match = cname_dest; 824 825 /* allocate the CNAME RR */ 826 rrset = (rrset_type*) region_alloc(q->region, sizeof(rrset_type)); 827 memset(rrset, 0, sizeof(rrset_type)); 828 rrset->zone = q->zone; 829 rrset->rr_count = 1; 830 rrset->rrs = (rr_type*) region_alloc(q->region, sizeof(rr_type)); 831 memset(rrset->rrs, 0, sizeof(rr_type)); 832 rrset->rrs->owner = cname_domain; 833 rrset->rrs->ttl = ttl; 834 rrset->rrs->type = TYPE_CNAME; 835 rrset->rrs->klass = CLASS_IN; 836 rrset->rrs->rdata_count = 1; 837 rrset->rrs->rdatas = (rdata_atom_type*)region_alloc(q->region, 838 sizeof(rdata_atom_type)); 839 rrset->rrs->rdatas->domain = cname_dest; 840 841 if(!add_rrset(q, answer, ANSWER_SECTION, cname_domain, rrset)) { 842 log_msg(LOG_ERR, "could not add synthesized CNAME rrset to packet"); 843 } 844 845 return cname_dest->number; 846 } 847 848 /* 849 * Answer delegation information. 850 * 851 * DNSSEC: Include the DS RRset if present. Otherwise include an NSEC 852 * record proving the DS RRset does not exist. 853 */ 854 static void 855 answer_delegation(query_type *query, answer_type *answer) 856 { 857 assert(answer); 858 assert(query->delegation_domain); 859 assert(query->delegation_rrset); 860 861 if (query->cname_count == 0) { 862 AA_CLR(query->packet); 863 } else { 864 AA_SET(query->packet); 865 } 866 867 add_rrset(query, 868 answer, 869 AUTHORITY_SECTION, 870 query->delegation_domain, 871 query->delegation_rrset); 872 if (query->edns.dnssec_ok && zone_is_secure(query->zone)) { 873 rrset_type *rrset; 874 if ((rrset = domain_find_rrset(query->delegation_domain, query->zone, TYPE_DS))) { 875 add_rrset(query, answer, AUTHORITY_SECTION, 876 query->delegation_domain, rrset); 877 #ifdef NSEC3 878 } else if (query->zone->nsec3_param) { 879 nsec3_answer_delegation(query, answer); 880 #endif 881 } else if ((rrset = domain_find_rrset(query->delegation_domain, query->zone, TYPE_NSEC))) { 882 add_rrset(query, answer, AUTHORITY_SECTION, 883 query->delegation_domain, rrset); 884 } 885 } 886 } 887 888 889 /* 890 * Answer SOA information. 891 */ 892 static void 893 answer_soa(struct query *query, answer_type *answer) 894 { 895 if (query->qclass != CLASS_ANY) { 896 add_rrset(query, answer, 897 AUTHORITY_SECTION, 898 query->zone->apex, 899 query->zone->soa_nx_rrset); 900 } 901 } 902 903 904 /* 905 * Answer that the domain name exists but there is no RRset with the 906 * requested type. 907 * 908 * DNSSEC: Include the correct NSEC record proving that the type does 909 * not exist. In the wildcard no data (3.1.3.4) case the wildcard IS 910 * NOT expanded, so the ORIGINAL parameter must point to the original 911 * wildcard entry, not to the generated entry. 912 */ 913 static void 914 answer_nodata(struct query *query, answer_type *answer, domain_type *original) 915 { 916 if (query->cname_count == 0) { 917 answer_soa(query, answer); 918 } 919 920 #ifdef NSEC3 921 if (query->edns.dnssec_ok && query->zone->nsec3_param) { 922 nsec3_answer_nodata(query, answer, original); 923 } else 924 #endif 925 if (query->edns.dnssec_ok && zone_is_secure(query->zone)) { 926 domain_type *nsec_domain; 927 rrset_type *nsec_rrset; 928 929 nsec_domain = find_covering_nsec(original, query->zone, &nsec_rrset); 930 if (nsec_domain) { 931 add_rrset(query, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset); 932 } 933 } 934 } 935 936 static void 937 answer_nxdomain(query_type *query, answer_type *answer) 938 { 939 RCODE_SET(query->packet, RCODE_NXDOMAIN); 940 answer_soa(query, answer); 941 } 942 943 944 /* 945 * Answer domain information (or SOA if we do not have an RRset for 946 * the type specified by the query). 947 */ 948 static void 949 answer_domain(struct nsd* nsd, struct query *q, answer_type *answer, 950 domain_type *domain, domain_type *original) 951 { 952 rrset_type *rrset; 953 954 if (q->qtype == TYPE_ANY) { 955 int added = 0; 956 for (rrset = domain_find_any_rrset(domain, q->zone); rrset; rrset = rrset->next) { 957 if (rrset->zone == q->zone 958 #ifdef NSEC3 959 && rrset_rrtype(rrset) != TYPE_NSEC3 960 #endif 961 /* 962 * Don't include the RRSIG RRset when 963 * DNSSEC is used, because it is added 964 * automatically on an per-RRset basis. 965 */ 966 && !(q->edns.dnssec_ok 967 && zone_is_secure(q->zone) 968 && rrset_rrtype(rrset) == TYPE_RRSIG)) 969 { 970 add_rrset(q, answer, ANSWER_SECTION, domain, rrset); 971 ++added; 972 } 973 } 974 if (added == 0) { 975 answer_nodata(q, answer, original); 976 return; 977 } 978 #ifdef NSEC3 979 } else if (q->qtype == TYPE_NSEC3) { 980 answer_nodata(q, answer, original); 981 return; 982 #endif 983 } else if ((rrset = domain_find_rrset(domain, q->zone, q->qtype))) { 984 add_rrset(q, answer, ANSWER_SECTION, domain, rrset); 985 } else if ((rrset = domain_find_rrset(domain, q->zone, TYPE_CNAME))) { 986 int added; 987 988 /* 989 * If the CNAME is not added it is already in the 990 * answer, so we have a CNAME loop. Don't follow the 991 * CNAME target in this case. 992 */ 993 added = add_rrset(q, answer, ANSWER_SECTION, domain, rrset); 994 assert(rrset->rr_count > 0); 995 if (added) { 996 /* only process first CNAME record */ 997 domain_type *closest_match = rdata_atom_domain(rrset->rrs[0].rdatas[0]); 998 domain_type *closest_encloser = closest_match; 999 zone_type* origzone = q->zone; 1000 ++q->cname_count; 1001 1002 answer_lookup_zone(nsd, q, answer, closest_match->number, 1003 closest_match == closest_encloser, 1004 closest_match, closest_encloser, 1005 domain_dname(closest_match)); 1006 q->zone = origzone; 1007 } 1008 return; 1009 } else { 1010 answer_nodata(q, answer, original); 1011 return; 1012 } 1013 1014 if (q->qclass != CLASS_ANY && q->zone->ns_rrset && answer_needs_ns(q) 1015 && !minimal_responses) { 1016 add_rrset(q, answer, OPTIONAL_AUTHORITY_SECTION, q->zone->apex, 1017 q->zone->ns_rrset); 1018 } 1019 } 1020 1021 1022 /* 1023 * Answer with authoritative data. If a wildcard is matched the owner 1024 * name will be expanded to the domain name specified by 1025 * DOMAIN_NUMBER. DOMAIN_NUMBER 0 (zero) is reserved for the original 1026 * query name. 1027 * 1028 * DNSSEC: Include the necessary NSEC records in case the request 1029 * domain name does not exist and/or a wildcard match does not exist. 1030 */ 1031 static void 1032 answer_authoritative(struct nsd *nsd, 1033 struct query *q, 1034 answer_type *answer, 1035 size_t domain_number, 1036 int exact, 1037 domain_type *closest_match, 1038 domain_type *closest_encloser, 1039 const dname_type *qname) 1040 { 1041 domain_type *match; 1042 domain_type *original = closest_match; 1043 domain_type *dname_ce; 1044 rrset_type *rrset; 1045 1046 #ifdef NSEC3 1047 if(exact && domain_has_only_NSEC3(closest_match, q->zone)) { 1048 exact = 0; /* pretend it does not exist */ 1049 if(closest_encloser->parent) 1050 closest_encloser = closest_encloser->parent; 1051 } 1052 #endif /* NSEC3 */ 1053 if((dname_ce = find_dname_above(closest_encloser, q->zone)) != NULL) { 1054 /* occlude the found data, the DNAME is closest_encloser */ 1055 closest_encloser = dname_ce; 1056 exact = 0; 1057 } 1058 1059 if (exact) { 1060 match = closest_match; 1061 } else if ((rrset=domain_find_rrset(closest_encloser, q->zone, TYPE_DNAME))) { 1062 /* process DNAME */ 1063 const dname_type* name = qname; 1064 domain_type *dest = rdata_atom_domain(rrset->rrs[0].rdatas[0]); 1065 int added; 1066 assert(rrset->rr_count > 0); 1067 if(domain_number != 0) /* we followed CNAMEs or DNAMEs */ 1068 name = domain_dname(closest_match); 1069 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "expanding DNAME for q=%s", dname_to_string(name, NULL))); 1070 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->src is %s", 1071 domain_to_string(closest_encloser))); 1072 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->dest is %s", 1073 domain_to_string(dest))); 1074 /* if the DNAME set is not added we have a loop, do not follow */ 1075 added = add_rrset(q, answer, ANSWER_SECTION, closest_encloser, rrset); 1076 if(added) { 1077 domain_type* src = closest_encloser; 1078 const dname_type* newname = dname_replace(q->region, name, 1079 domain_dname(src), domain_dname(dest)); 1080 size_t newnum = 0; 1081 zone_type* origzone = q->zone; 1082 ++q->cname_count; 1083 if(!newname) { /* newname too long */ 1084 RCODE_SET(q->packet, RCODE_YXDOMAIN); 1085 return; 1086 } 1087 DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->result is %s", dname_to_string(newname, NULL))); 1088 /* follow the DNAME */ 1089 (void)namedb_lookup(nsd->db, newname, &closest_match, &closest_encloser); 1090 /* synthesize CNAME record */ 1091 newnum = query_synthesize_cname(q, answer, name, newname, 1092 src, closest_encloser, &closest_match, rrset->rrs[0].ttl); 1093 if(!newnum) { 1094 /* could not synthesize the CNAME. */ 1095 /* return previous CNAMEs to make resolver recurse for us */ 1096 return; 1097 } 1098 1099 answer_lookup_zone(nsd, q, answer, newnum, 1100 closest_match == closest_encloser, 1101 closest_match, closest_encloser, newname); 1102 q->zone = origzone; 1103 } 1104 if(!added) /* log the error so operator can find looping recursors */ 1105 log_msg(LOG_INFO, "DNAME processing stopped due to loop, qname %s", 1106 dname_to_string(q->qname, NULL)); 1107 return; 1108 } else if (domain_wildcard_child(closest_encloser)) { 1109 /* Generate the domain from the wildcard. */ 1110 domain_type *wildcard_child = domain_wildcard_child(closest_encloser); 1111 #ifdef RATELIMIT 1112 q->wildcard_domain = wildcard_child; 1113 #endif 1114 1115 match = (domain_type *) region_alloc(q->region, 1116 sizeof(domain_type)); 1117 #ifdef USE_RADIX_TREE 1118 match->rnode = NULL; 1119 match->dname = wildcard_child->dname; 1120 #else 1121 memcpy(&match->node, &wildcard_child->node, sizeof(rbnode_type)); 1122 match->node.parent = NULL; 1123 #endif 1124 match->parent = closest_encloser; 1125 match->wildcard_child_closest_match = match; 1126 match->number = domain_number; 1127 match->rrsets = wildcard_child->rrsets; 1128 match->is_existing = wildcard_child->is_existing; 1129 #ifdef NSEC3 1130 match->nsec3 = wildcard_child->nsec3; 1131 /* copy over these entries: 1132 match->nsec3_is_exact = wildcard_child->nsec3_is_exact; 1133 match->nsec3_cover = wildcard_child->nsec3_cover; 1134 match->nsec3_wcard_child_cover = wildcard_child->nsec3_wcard_child_cover; 1135 match->nsec3_ds_parent_is_exact = wildcard_child->nsec3_ds_parent_is_exact; 1136 match->nsec3_ds_parent_cover = wildcard_child->nsec3_ds_parent_cover; 1137 */ 1138 1139 if (q->edns.dnssec_ok && q->zone->nsec3_param) { 1140 /* Only add nsec3 wildcard data when do bit is set */ 1141 nsec3_answer_wildcard(q, answer, wildcard_child, qname); 1142 } 1143 #endif 1144 1145 /* 1146 * Remember the original domain in case a Wildcard No 1147 * Data (3.1.3.4) response needs to be generated. In 1148 * this particular case the wildcard IS NOT 1149 * expanded. 1150 */ 1151 original = wildcard_child; 1152 } else { 1153 match = NULL; 1154 } 1155 1156 /* Authoritative zone. */ 1157 #ifdef NSEC3 1158 if (q->edns.dnssec_ok && q->zone->nsec3_param) { 1159 nsec3_answer_authoritative(&match, q, answer, 1160 closest_encloser, qname); 1161 } else 1162 #endif 1163 if (q->edns.dnssec_ok && zone_is_secure(q->zone)) { 1164 if (match != closest_encloser) { 1165 domain_type *nsec_domain; 1166 rrset_type *nsec_rrset; 1167 1168 /* 1169 * No match found or generated from wildcard, 1170 * include NSEC record. 1171 */ 1172 nsec_domain = find_covering_nsec(closest_match, q->zone, &nsec_rrset); 1173 if (nsec_domain) { 1174 add_rrset(q, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset); 1175 } 1176 } 1177 if (!match) { 1178 domain_type *nsec_domain; 1179 rrset_type *nsec_rrset; 1180 1181 /* 1182 * No match and no wildcard. Include NSEC 1183 * proving there is no wildcard. 1184 */ 1185 nsec_domain = find_covering_nsec(closest_encloser->wildcard_child_closest_match, q->zone, &nsec_rrset); 1186 if (nsec_domain) { 1187 add_rrset(q, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset); 1188 } 1189 } 1190 } 1191 1192 #ifdef NSEC3 1193 if (RCODE(q->packet)!=RCODE_OK) { 1194 return; /* nsec3 collision failure */ 1195 } 1196 #endif 1197 if (match) { 1198 answer_domain(nsd, q, answer, match, original); 1199 } else { 1200 answer_nxdomain(q, answer); 1201 } 1202 } 1203 1204 /* 1205 * qname may be different after CNAMEs have been followed from query->qname. 1206 */ 1207 static void 1208 answer_lookup_zone(struct nsd *nsd, struct query *q, answer_type *answer, 1209 size_t domain_number, int exact, domain_type *closest_match, 1210 domain_type *closest_encloser, const dname_type *qname) 1211 { 1212 q->zone = domain_find_zone(nsd->db, closest_encloser); 1213 if (!q->zone) { 1214 /* no zone for this */ 1215 if(q->cname_count == 0) 1216 RCODE_SET(q->packet, RCODE_REFUSE); 1217 return; 1218 } 1219 assert(closest_encloser); /* otherwise, no q->zone would be found */ 1220 if(!q->zone->apex || !q->zone->soa_rrset) { 1221 /* zone is configured but not loaded */ 1222 if(q->cname_count == 0) 1223 RCODE_SET(q->packet, RCODE_SERVFAIL); 1224 return; 1225 } 1226 /* now move up the closest encloser until it exists, previous 1227 * (possibly empty) closest encloser was useful to finding the zone 1228 * (for empty zones too), but now we want actual data nodes */ 1229 if (closest_encloser && !closest_encloser->is_existing) { 1230 exact = 0; 1231 while (closest_encloser != NULL && !closest_encloser->is_existing) 1232 closest_encloser = closest_encloser->parent; 1233 } 1234 1235 /* 1236 * See RFC 4035 (DNSSEC protocol) section 3.1.4.1 Responding 1237 * to Queries for DS RRs. 1238 */ 1239 if (exact && q->qtype == TYPE_DS && closest_encloser == q->zone->apex) { 1240 /* 1241 * Type DS query at a zone cut, use the responsible 1242 * parent zone to generate the answer if we are 1243 * authoritative for the parent zone. 1244 */ 1245 zone_type *zone = domain_find_parent_zone(nsd->db, q->zone); 1246 if (zone) { 1247 q->zone = zone; 1248 if(!q->zone->apex || !q->zone->soa_rrset) { 1249 /* zone is configured but not loaded */ 1250 if(q->cname_count == 0) 1251 RCODE_SET(q->packet, RCODE_SERVFAIL); 1252 return; 1253 } 1254 } 1255 } 1256 1257 /* see if the zone has expired (for secondary zones) */ 1258 if(q->zone && q->zone->opts && q->zone->opts->pattern && 1259 q->zone->opts->pattern->request_xfr != 0 && !q->zone->is_ok) { 1260 if(q->cname_count == 0) 1261 RCODE_SET(q->packet, RCODE_SERVFAIL); 1262 return; 1263 } 1264 1265 if (exact && q->qtype == TYPE_DS && closest_encloser == q->zone->apex) { 1266 /* 1267 * Type DS query at the zone apex (and the server is 1268 * not authoritative for the parent zone). 1269 */ 1270 if (q->qclass == CLASS_ANY) { 1271 AA_CLR(q->packet); 1272 } else { 1273 AA_SET(q->packet); 1274 } 1275 answer_nodata(q, answer, closest_encloser); 1276 } else { 1277 q->delegation_domain = domain_find_ns_rrsets( 1278 closest_encloser, q->zone, &q->delegation_rrset); 1279 if(q->delegation_domain && find_dname_above(q->delegation_domain, q->zone)) { 1280 q->delegation_domain = NULL; /* use higher DNAME */ 1281 } 1282 1283 if (!q->delegation_domain 1284 || (exact && q->qtype == TYPE_DS && closest_encloser == q->delegation_domain)) 1285 { 1286 if (q->qclass == CLASS_ANY) { 1287 AA_CLR(q->packet); 1288 } else { 1289 AA_SET(q->packet); 1290 } 1291 answer_authoritative(nsd, q, answer, domain_number, exact, 1292 closest_match, closest_encloser, qname); 1293 } 1294 else { 1295 answer_delegation(q, answer); 1296 } 1297 } 1298 } 1299 1300 static void 1301 answer_query(struct nsd *nsd, struct query *q) 1302 { 1303 domain_type *closest_match; 1304 domain_type *closest_encloser; 1305 int exact; 1306 uint16_t offset; 1307 answer_type answer; 1308 1309 answer_init(&answer); 1310 1311 exact = namedb_lookup(nsd->db, q->qname, &closest_match, &closest_encloser); 1312 1313 answer_lookup_zone(nsd, q, &answer, 0, exact, closest_match, 1314 closest_encloser, q->qname); 1315 ZTATUP2(nsd, q->zone, opcode, q->opcode); 1316 ZTATUP2(nsd, q->zone, qtype, q->qtype); 1317 ZTATUP2(nsd, q->zone, qclass, q->qclass); 1318 1319 offset = dname_label_offsets(q->qname)[domain_dname(closest_encloser)->label_count - 1] + QHEADERSZ; 1320 query_add_compression_domain(q, closest_encloser, offset); 1321 encode_answer(q, &answer); 1322 query_clear_compression_tables(q); 1323 } 1324 1325 void 1326 query_prepare_response(query_type *q) 1327 { 1328 uint16_t flags; 1329 1330 /* 1331 * Preserve the data up-to the current packet's limit. 1332 */ 1333 buffer_set_position(q->packet, buffer_limit(q->packet)); 1334 buffer_set_limit(q->packet, buffer_capacity(q->packet)); 1335 1336 /* 1337 * Reserve space for the EDNS records if required. 1338 */ 1339 q->reserved_space = edns_reserved_space(&q->edns); 1340 q->reserved_space += tsig_reserved_space(&q->tsig); 1341 1342 /* Update the flags. */ 1343 flags = FLAGS(q->packet); 1344 flags &= 0x0100U; /* Preserve the RD flag. */ 1345 /* CD flag must be cleared for auth answers */ 1346 flags |= 0x8000U; /* Set the QR flag. */ 1347 FLAGS_SET(q->packet, flags); 1348 } 1349 1350 /* 1351 * Processes the query. 1352 * 1353 */ 1354 query_state_type 1355 query_process(query_type *q, nsd_type *nsd) 1356 { 1357 /* The query... */ 1358 nsd_rc_type rc; 1359 query_state_type query_state; 1360 uint16_t arcount; 1361 1362 /* Sanity checks */ 1363 if (buffer_limit(q->packet) < QHEADERSZ) { 1364 /* packet too small to contain DNS header. 1365 Now packet investigation macros will work without problems. */ 1366 return QUERY_DISCARDED; 1367 } 1368 if (QR(q->packet)) { 1369 /* Not a query? Drop it on the floor. */ 1370 return QUERY_DISCARDED; 1371 } 1372 1373 /* check opcode early on, because new opcodes may have different 1374 * specification of the meaning of the rest of the packet */ 1375 q->opcode = OPCODE(q->packet); 1376 if(q->opcode != OPCODE_QUERY && q->opcode != OPCODE_NOTIFY) { 1377 if(query_ratelimit_err(nsd)) 1378 return QUERY_DISCARDED; 1379 return query_error(q, NSD_RC_IMPL); 1380 } 1381 1382 if (RCODE(q->packet) != RCODE_OK || !process_query_section(q)) { 1383 return query_formerr(q, nsd); 1384 } 1385 1386 /* Update statistics. */ 1387 STATUP2(nsd, opcode, q->opcode); 1388 STATUP2(nsd, qtype, q->qtype); 1389 STATUP2(nsd, qclass, q->qclass); 1390 1391 if (q->opcode != OPCODE_QUERY) { 1392 if (q->opcode == OPCODE_NOTIFY) { 1393 return answer_notify(nsd, q); 1394 } else { 1395 if(query_ratelimit_err(nsd)) 1396 return QUERY_DISCARDED; 1397 return query_error(q, NSD_RC_IMPL); 1398 } 1399 } 1400 1401 /* Dont bother to answer more than one question at once... */ 1402 if (QDCOUNT(q->packet) != 1) { 1403 FLAGS_SET(q->packet, 0); 1404 return query_formerr(q, nsd); 1405 } 1406 /* Ignore settings of flags */ 1407 1408 /* Dont allow any records in the answer or authority section... 1409 except for IXFR queries. */ 1410 if (ANCOUNT(q->packet) != 0 || 1411 (q->qtype!=TYPE_IXFR && NSCOUNT(q->packet) != 0)) { 1412 return query_formerr(q, nsd); 1413 } 1414 if(q->qtype==TYPE_IXFR && NSCOUNT(q->packet) > 0) { 1415 int i; /* skip ixfr soa information data here */ 1416 for(i=0; i< NSCOUNT(q->packet); i++) 1417 if(!packet_skip_rr(q->packet, 0)) 1418 return query_formerr(q, nsd); 1419 } 1420 1421 arcount = ARCOUNT(q->packet); 1422 if (arcount > 0) { 1423 /* According to draft-ietf-dnsext-rfc2671bis-edns0-10: 1424 * "The placement flexibility for the OPT RR does not 1425 * override the need for the TSIG or SIG(0) RRs to be 1426 * the last in the additional section whenever they are 1427 * present." 1428 * So we should not have to check for TSIG RR before 1429 * OPT RR. Keep the code for backwards compatibility. 1430 */ 1431 1432 /* see if tsig is before edns record */ 1433 if (!tsig_parse_rr(&q->tsig, q->packet)) 1434 return query_formerr(q, nsd); 1435 if(q->tsig.status != TSIG_NOT_PRESENT) 1436 --arcount; 1437 } 1438 /* See if there is an OPT RR. */ 1439 if (arcount > 0) { 1440 if (edns_parse_record(&q->edns, q->packet, q, nsd)) 1441 --arcount; 1442 } 1443 /* See if there is a TSIG RR. */ 1444 if (arcount > 0 && q->tsig.status == TSIG_NOT_PRESENT) { 1445 /* see if tsig is after the edns record */ 1446 if (!tsig_parse_rr(&q->tsig, q->packet)) 1447 return query_formerr(q, nsd); 1448 if(q->tsig.status != TSIG_NOT_PRESENT) 1449 --arcount; 1450 } 1451 /* If more RRs left in Add. Section, FORMERR. */ 1452 if (arcount > 0) { 1453 return query_formerr(q, nsd); 1454 } 1455 1456 /* Do we have any trailing garbage? */ 1457 #ifdef STRICT_MESSAGE_PARSE 1458 if (buffer_remaining(q->packet) > 0) { 1459 /* If we're strict.... */ 1460 return query_formerr(q, nsd); 1461 } 1462 #endif 1463 /* Remove trailing garbage. */ 1464 buffer_set_limit(q->packet, buffer_position(q->packet)); 1465 1466 rc = process_tsig(q); 1467 if (rc != NSD_RC_OK) { 1468 return query_error(q, rc); 1469 } 1470 rc = process_edns(nsd, q); 1471 if (rc != NSD_RC_OK) { 1472 /* We should not return FORMERR, but BADVERS (=16). 1473 * BADVERS is created with Ext. RCODE, followed by RCODE. 1474 * Ext. RCODE is set to 1, RCODE must be 0 (getting 0x10 = 16). 1475 * Thus RCODE = NOERROR = NSD_RC_OK. */ 1476 return query_error(q, NSD_RC_OK); 1477 } 1478 1479 query_prepare_response(q); 1480 1481 if (q->qclass != CLASS_IN && q->qclass != CLASS_ANY) { 1482 if (q->qclass == CLASS_CH) { 1483 return answer_chaos(nsd, q); 1484 } else { 1485 return query_error(q, NSD_RC_REFUSE); 1486 } 1487 } 1488 1489 query_state = answer_axfr_ixfr(nsd, q); 1490 if (query_state == QUERY_PROCESSED || query_state == QUERY_IN_AXFR) { 1491 return query_state; 1492 } 1493 if(q->qtype == TYPE_ANY && nsd->options->refuse_any && !q->tcp) { 1494 TC_SET(q->packet); 1495 return query_error(q, NSD_RC_OK); 1496 } 1497 1498 answer_query(nsd, q); 1499 1500 return QUERY_PROCESSED; 1501 } 1502 1503 void 1504 query_add_optional(query_type *q, nsd_type *nsd) 1505 { 1506 struct edns_data *edns = &nsd->edns_ipv4; 1507 #if defined(INET6) 1508 if (q->addr.ss_family == AF_INET6) { 1509 edns = &nsd->edns_ipv6; 1510 } 1511 #endif 1512 if (RCODE(q->packet) == RCODE_FORMAT) { 1513 return; 1514 } 1515 switch (q->edns.status) { 1516 case EDNS_NOT_PRESENT: 1517 break; 1518 case EDNS_OK: 1519 if (q->edns.dnssec_ok) edns->ok[7] = 0x80; 1520 else edns->ok[7] = 0x00; 1521 buffer_write(q->packet, edns->ok, OPT_LEN); 1522 if(q->edns.opt_reserved_space == 0 || !buffer_available( 1523 q->packet, 2+q->edns.opt_reserved_space)) { 1524 /* fill with NULLs */ 1525 buffer_write(q->packet, edns->rdata_none, OPT_RDATA); 1526 } else { 1527 /* rdata length */ 1528 buffer_write_u16(q->packet, q->edns.opt_reserved_space); 1529 /* edns options */ 1530 if(q->edns.nsid) { 1531 /* nsid opt header */ 1532 buffer_write(q->packet, edns->nsid, OPT_HDR); 1533 /* nsid payload */ 1534 buffer_write(q->packet, nsd->nsid, nsd->nsid_len); 1535 } 1536 } 1537 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1); 1538 STATUP(nsd, edns); 1539 ZTATUP(nsd, q->zone, edns); 1540 break; 1541 case EDNS_ERROR: 1542 if (q->edns.dnssec_ok) edns->error[7] = 0x80; 1543 else edns->error[7] = 0x00; 1544 buffer_write(q->packet, edns->error, OPT_LEN); 1545 buffer_write(q->packet, edns->rdata_none, OPT_RDATA); 1546 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1); 1547 STATUP(nsd, ednserr); 1548 ZTATUP(nsd, q->zone, ednserr); 1549 break; 1550 } 1551 1552 if (q->tsig.status != TSIG_NOT_PRESENT) { 1553 if (q->tsig.status == TSIG_ERROR || 1554 q->tsig.error_code != TSIG_ERROR_NOERROR) { 1555 tsig_error_reply(&q->tsig); 1556 tsig_append_rr(&q->tsig, q->packet); 1557 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1); 1558 } else if(q->tsig.status == TSIG_OK && 1559 q->tsig.error_code == TSIG_ERROR_NOERROR) 1560 { 1561 if(q->tsig_prepare_it) 1562 tsig_prepare(&q->tsig); 1563 if(q->tsig_update_it) 1564 tsig_update(&q->tsig, q->packet, buffer_position(q->packet)); 1565 if(q->tsig_sign_it) { 1566 tsig_sign(&q->tsig); 1567 tsig_append_rr(&q->tsig, q->packet); 1568 ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1); 1569 } 1570 } 1571 } 1572 } 1573