1 #if !defined(lint) && !defined(SABER) 2 static const char rcsid[] = "$Id: res_findzonecut.c,v 1.10 2005/10/11 00:10:16 marka Exp $"; 3 #endif /* not lint */ 4 5 /*- 6 * SPDX-License-Identifier: ISC 7 * 8 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 9 * Copyright (c) 1999 by Internet Software Consortium. 10 * 11 * Permission to use, copy, modify, and distribute this software for any 12 * purpose with or without fee is hereby granted, provided that the above 13 * copyright notice and this permission notice appear in all copies. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 16 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 17 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 18 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 19 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 20 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 21 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 22 */ 23 24 /* Import. */ 25 26 #include "port_before.h" 27 28 #include <sys/param.h> 29 #include <sys/socket.h> 30 #include <sys/time.h> 31 32 #include <netinet/in.h> 33 #include <arpa/inet.h> 34 #include <arpa/nameser.h> 35 36 #include <errno.h> 37 #include <limits.h> 38 #include <netdb.h> 39 #include <stdarg.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 44 #include <isc/list.h> 45 46 #include "port_after.h" 47 48 #include <resolv.h> 49 50 /* Data structures. */ 51 52 typedef struct rr_a { 53 LINK(struct rr_a) link; 54 union res_sockaddr_union addr; 55 } rr_a; 56 typedef LIST(rr_a) rrset_a; 57 58 typedef struct rr_ns { 59 LINK(struct rr_ns) link; 60 const char * name; 61 unsigned int flags; 62 rrset_a addrs; 63 } rr_ns; 64 typedef LIST(rr_ns) rrset_ns; 65 66 #define RR_NS_HAVE_V4 0x01 67 #define RR_NS_HAVE_V6 0x02 68 69 /* Forward. */ 70 71 static int satisfy(res_state, const char *, rrset_ns *, 72 union res_sockaddr_union *, int); 73 static int add_addrs(res_state, rr_ns *, 74 union res_sockaddr_union *, int); 75 static int get_soa(res_state, const char *, ns_class, int, 76 char *, size_t, char *, size_t, 77 rrset_ns *); 78 static int get_ns(res_state, const char *, ns_class, int, rrset_ns *); 79 static int get_glue(res_state, ns_class, int, rrset_ns *); 80 static int save_ns(res_state, ns_msg *, ns_sect, 81 const char *, ns_class, int, rrset_ns *); 82 static int save_a(res_state, ns_msg *, ns_sect, 83 const char *, ns_class, int, rr_ns *); 84 static void free_nsrrset(rrset_ns *); 85 static void free_nsrr(rrset_ns *, rr_ns *); 86 static rr_ns * find_ns(rrset_ns *, const char *); 87 static int do_query(res_state, const char *, ns_class, ns_type, 88 u_char *, ns_msg *); 89 static void res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2); 90 91 /* Macros. */ 92 93 #define DPRINTF(x) do {\ 94 int save_errno = errno; \ 95 if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \ 96 errno = save_errno; \ 97 } while (0) 98 99 /* Public. */ 100 101 /*% 102 * find enclosing zone for a <dname,class>, and some server addresses 103 * 104 * parameters: 105 *\li res - resolver context to work within (is modified) 106 *\li dname - domain name whose enclosing zone is desired 107 *\li class - class of dname (and its enclosing zone) 108 *\li zname - found zone name 109 *\li zsize - allocated size of zname 110 *\li addrs - found server addresses 111 *\li naddrs - max number of addrs 112 * 113 * return values: 114 *\li < 0 - an error occurred (check errno) 115 *\li = 0 - zname is now valid, but addrs[] wasn't changed 116 *\li > 0 - zname is now valid, and return value is number of addrs[] found 117 * 118 * notes: 119 *\li this function calls res_nsend() which means it depends on correctly 120 * functioning recursive nameservers (usually defined in /etc/resolv.conf 121 * or its local equivalent). 122 * 123 *\li we start by asking for an SOA<dname,class>. if we get one as an 124 * answer, that just means <dname,class> is a zone top, which is fine. 125 * more than likely we'll be told to go pound sand, in the form of a 126 * negative answer. 127 * 128 *\li note that we are not prepared to deal with referrals since that would 129 * only come from authority servers and our correctly functioning local 130 * recursive server would have followed the referral and got us something 131 * more definite. 132 * 133 *\li if the authority section contains an SOA, this SOA should also be the 134 * closest enclosing zone, since any intermediary zone cuts would've been 135 * returned as referrals and dealt with by our correctly functioning local 136 * recursive name server. but an SOA in the authority section should NOT 137 * match our dname (since that would have been returned in the answer 138 * section). an authority section SOA has to be "above" our dname. 139 * 140 *\li however, since authority section SOA's were once optional, it's 141 * possible that we'll have to go hunting for the enclosing SOA by 142 * ripping labels off the front of our dname -- this is known as "doing 143 * it the hard way." 144 * 145 *\li ultimately we want some server addresses, which are ideally the ones 146 * pertaining to the SOA.MNAME, but only if there is a matching NS RR. 147 * so the second phase (after we find an SOA) is to go looking for the 148 * NS RRset for that SOA's zone. 149 * 150 *\li no answer section processed by this code is allowed to contain CNAME 151 * or DNAME RR's. for the SOA query this means we strip a label and 152 * keep going. for the NS and A queries this means we just give up. 153 */ 154 155 #ifndef _LIBC 156 int 157 res_findzonecut(res_state statp, const char *dname, ns_class class, int opts, 158 char *zname, size_t zsize, struct in_addr *addrs, int naddrs) 159 { 160 int result, i; 161 union res_sockaddr_union *u; 162 163 164 opts |= RES_IPV4ONLY; 165 opts &= ~RES_IPV6ONLY; 166 167 u = calloc(naddrs, sizeof(*u)); 168 if (u == NULL) 169 return(-1); 170 171 result = res_findzonecut2(statp, dname, class, opts, zname, zsize, 172 u, naddrs); 173 174 for (i = 0; i < result; i++) { 175 addrs[i] = u[i].sin.sin_addr; 176 } 177 free(u); 178 return (result); 179 } 180 #endif 181 182 int 183 res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts, 184 char *zname, size_t zsize, union res_sockaddr_union *addrs, 185 int naddrs) 186 { 187 char mname[NS_MAXDNAME]; 188 u_long save_pfcode; 189 rrset_ns nsrrs; 190 int n; 191 192 DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d", 193 dname, p_class(class), (long)zsize, naddrs)); 194 save_pfcode = statp->pfcode; 195 statp->pfcode |= RES_PRF_HEAD2 | RES_PRF_HEAD1 | RES_PRF_HEADX | 196 RES_PRF_QUES | RES_PRF_ANS | 197 RES_PRF_AUTH | RES_PRF_ADD; 198 INIT_LIST(nsrrs); 199 200 DPRINTF(("get the soa, and see if it has enough glue")); 201 if ((n = get_soa(statp, dname, class, opts, zname, zsize, 202 mname, sizeof mname, &nsrrs)) < 0 || 203 ((opts & RES_EXHAUSTIVE) == 0 && 204 (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0)) 205 goto done; 206 207 DPRINTF(("get the ns rrset and see if it has enough glue")); 208 if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 || 209 ((opts & RES_EXHAUSTIVE) == 0 && 210 (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0)) 211 goto done; 212 213 DPRINTF(("get the missing glue and see if it's finally enough")); 214 if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0) 215 n = satisfy(statp, mname, &nsrrs, addrs, naddrs); 216 217 done: 218 DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK")); 219 free_nsrrset(&nsrrs); 220 statp->pfcode = save_pfcode; 221 return (n); 222 } 223 224 /* Private. */ 225 226 static int 227 satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp, 228 union res_sockaddr_union *addrs, int naddrs) 229 { 230 rr_ns *nsrr; 231 int n, x; 232 233 n = 0; 234 nsrr = find_ns(nsrrsp, mname); 235 if (nsrr != NULL) { 236 x = add_addrs(statp, nsrr, addrs, naddrs); 237 addrs += x; 238 naddrs -= x; 239 n += x; 240 } 241 for (nsrr = HEAD(*nsrrsp); 242 nsrr != NULL && naddrs > 0; 243 nsrr = NEXT(nsrr, link)) 244 if (ns_samename(nsrr->name, mname) != 1) { 245 x = add_addrs(statp, nsrr, addrs, naddrs); 246 addrs += x; 247 naddrs -= x; 248 n += x; 249 } 250 DPRINTF(("satisfy(%s): %d", mname, n)); 251 return (n); 252 } 253 254 static int 255 add_addrs(res_state statp, rr_ns *nsrr, 256 union res_sockaddr_union *addrs, int naddrs) 257 { 258 rr_a *arr; 259 int n = 0; 260 261 for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) { 262 if (naddrs <= 0) 263 return (0); 264 *addrs++ = arr->addr; 265 naddrs--; 266 n++; 267 } 268 DPRINTF(("add_addrs: %d", n)); 269 return (n); 270 } 271 272 static int 273 get_soa(res_state statp, const char *dname, ns_class class, int opts, 274 char *zname, size_t zsize, char *mname, size_t msize, 275 rrset_ns *nsrrsp) 276 { 277 char tname[NS_MAXDNAME]; 278 u_char *resp = NULL; 279 int n, i, ancount, nscount; 280 ns_sect sect; 281 ns_msg msg; 282 u_int rcode; 283 284 /* 285 * Find closest enclosing SOA, even if it's for the root zone. 286 */ 287 288 /* First canonicalize dname (exactly one unescaped trailing "."). */ 289 if (ns_makecanon(dname, tname, sizeof tname) < 0) 290 goto cleanup; 291 dname = tname; 292 293 resp = malloc(NS_MAXMSG); 294 if (resp == NULL) 295 goto cleanup; 296 297 /* Now grovel the subdomains, hunting for an SOA answer or auth. */ 298 for (;;) { 299 /* Leading or inter-label '.' are skipped here. */ 300 while (*dname == '.') 301 dname++; 302 303 /* Is there an SOA? */ 304 n = do_query(statp, dname, class, ns_t_soa, resp, &msg); 305 if (n < 0) { 306 DPRINTF(("get_soa: do_query('%s', %s) failed (%d)", 307 dname, p_class(class), n)); 308 goto cleanup; 309 } 310 if (n > 0) { 311 DPRINTF(("get_soa: CNAME or DNAME found")); 312 sect = ns_s_max, n = 0; 313 } else { 314 rcode = ns_msg_getflag(msg, ns_f_rcode); 315 ancount = ns_msg_count(msg, ns_s_an); 316 nscount = ns_msg_count(msg, ns_s_ns); 317 if (ancount > 0 && rcode == ns_r_noerror) 318 sect = ns_s_an, n = ancount; 319 else if (nscount > 0) 320 sect = ns_s_ns, n = nscount; 321 else 322 sect = ns_s_max, n = 0; 323 } 324 for (i = 0; i < n; i++) { 325 const char *t; 326 const u_char *rdata; 327 ns_rr rr; 328 329 if (ns_parserr(&msg, sect, i, &rr) < 0) { 330 DPRINTF(("get_soa: ns_parserr(%s, %d) failed", 331 p_section(sect, ns_o_query), i)); 332 goto cleanup; 333 } 334 if (ns_rr_type(rr) == ns_t_cname || 335 ns_rr_type(rr) == ns_t_dname) 336 break; 337 if (ns_rr_type(rr) != ns_t_soa || 338 ns_rr_class(rr) != class) 339 continue; 340 t = ns_rr_name(rr); 341 switch (sect) { 342 case ns_s_an: 343 if (ns_samedomain(dname, t) == 0) { 344 DPRINTF( 345 ("get_soa: ns_samedomain('%s', '%s') == 0", 346 dname, t) 347 ); 348 errno = EPROTOTYPE; 349 goto cleanup; 350 } 351 break; 352 case ns_s_ns: 353 if (ns_samename(dname, t) == 1 || 354 ns_samedomain(dname, t) == 0) { 355 DPRINTF( 356 ("get_soa: ns_samename() || !ns_samedomain('%s', '%s')", 357 dname, t) 358 ); 359 errno = EPROTOTYPE; 360 goto cleanup; 361 } 362 break; 363 default: 364 abort(); 365 } 366 if (strlen(t) + 1 > zsize) { 367 DPRINTF(("get_soa: zname(%lu) too small (%lu)", 368 (unsigned long)zsize, 369 (unsigned long)strlen(t) + 1)); 370 errno = EMSGSIZE; 371 goto cleanup; 372 } 373 strcpy(zname, t); 374 rdata = ns_rr_rdata(rr); 375 if (ns_name_uncompress(resp, ns_msg_end(msg), rdata, 376 mname, msize) < 0) { 377 DPRINTF(("get_soa: ns_name_uncompress failed") 378 ); 379 goto cleanup; 380 } 381 if (save_ns(statp, &msg, ns_s_ns, 382 zname, class, opts, nsrrsp) < 0) { 383 DPRINTF(("get_soa: save_ns failed")); 384 goto cleanup; 385 } 386 free(resp); 387 return (0); 388 } 389 390 /* If we're out of labels, then not even "." has an SOA! */ 391 if (*dname == '\0') 392 break; 393 394 /* Find label-terminating "."; top of loop will skip it. */ 395 while (*dname != '.') { 396 if (*dname == '\\') 397 if (*++dname == '\0') { 398 errno = EMSGSIZE; 399 goto cleanup; 400 } 401 dname++; 402 } 403 } 404 DPRINTF(("get_soa: out of labels")); 405 errno = EDESTADDRREQ; 406 cleanup: 407 if (resp != NULL) 408 free(resp); 409 return (-1); 410 } 411 412 static int 413 get_ns(res_state statp, const char *zname, ns_class class, int opts, 414 rrset_ns *nsrrsp) 415 { 416 u_char *resp; 417 ns_msg msg; 418 int n; 419 420 resp = malloc(NS_MAXMSG); 421 if (resp == NULL) 422 return (-1); 423 424 /* Go and get the NS RRs for this zone. */ 425 n = do_query(statp, zname, class, ns_t_ns, resp, &msg); 426 if (n != 0) { 427 DPRINTF(("get_ns: do_query('%s', %s) failed (%d)", 428 zname, p_class(class), n)); 429 free(resp); 430 return (-1); 431 } 432 433 /* Remember the NS RRs and associated A RRs that came back. */ 434 if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) { 435 DPRINTF(("get_ns save_ns('%s', %s) failed", 436 zname, p_class(class))); 437 free(resp); 438 return (-1); 439 } 440 441 free(resp); 442 return (0); 443 } 444 445 static int 446 get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) { 447 rr_ns *nsrr, *nsrr_n; 448 u_char *resp; 449 450 resp = malloc(NS_MAXMSG); 451 if (resp == NULL) 452 return(-1); 453 454 /* Go and get the A RRs for each empty NS RR on our list. */ 455 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) { 456 ns_msg msg; 457 int n; 458 459 nsrr_n = NEXT(nsrr, link); 460 461 if ((nsrr->flags & RR_NS_HAVE_V4) == 0) { 462 n = do_query(statp, nsrr->name, class, ns_t_a, 463 resp, &msg); 464 if (n < 0) { 465 DPRINTF( 466 ("get_glue: do_query('%s', %s') failed", 467 nsrr->name, p_class(class))); 468 goto cleanup; 469 } 470 if (n > 0) { 471 DPRINTF(( 472 "get_glue: do_query('%s', %s') CNAME or DNAME found", 473 nsrr->name, p_class(class))); 474 } 475 if (save_a(statp, &msg, ns_s_an, nsrr->name, class, 476 opts, nsrr) < 0) { 477 DPRINTF(("get_glue: save_r('%s', %s) failed", 478 nsrr->name, p_class(class))); 479 goto cleanup; 480 } 481 } 482 483 if ((nsrr->flags & RR_NS_HAVE_V6) == 0) { 484 n = do_query(statp, nsrr->name, class, ns_t_aaaa, 485 resp, &msg); 486 if (n < 0) { 487 DPRINTF( 488 ("get_glue: do_query('%s', %s') failed", 489 nsrr->name, p_class(class))); 490 goto cleanup; 491 } 492 if (n > 0) { 493 DPRINTF(( 494 "get_glue: do_query('%s', %s') CNAME or DNAME found", 495 nsrr->name, p_class(class))); 496 } 497 if (save_a(statp, &msg, ns_s_an, nsrr->name, class, 498 opts, nsrr) < 0) { 499 DPRINTF(("get_glue: save_r('%s', %s) failed", 500 nsrr->name, p_class(class))); 501 goto cleanup; 502 } 503 } 504 505 /* If it's still empty, it's just chaff. */ 506 if (EMPTY(nsrr->addrs)) { 507 DPRINTF(("get_glue: removing empty '%s' NS", 508 nsrr->name)); 509 free_nsrr(nsrrsp, nsrr); 510 } 511 } 512 free(resp); 513 return (0); 514 515 cleanup: 516 free(resp); 517 return (-1); 518 } 519 520 static int 521 save_ns(res_state statp, ns_msg *msg, ns_sect sect, 522 const char *owner, ns_class class, int opts, 523 rrset_ns *nsrrsp) 524 { 525 int i; 526 527 for (i = 0; i < ns_msg_count(*msg, sect); i++) { 528 char tname[MAXDNAME]; 529 const u_char *rdata; 530 rr_ns *nsrr; 531 ns_rr rr; 532 533 if (ns_parserr(msg, sect, i, &rr) < 0) { 534 DPRINTF(("save_ns: ns_parserr(%s, %d) failed", 535 p_section(sect, ns_o_query), i)); 536 return (-1); 537 } 538 if (ns_rr_type(rr) != ns_t_ns || 539 ns_rr_class(rr) != class || 540 ns_samename(ns_rr_name(rr), owner) != 1) 541 continue; 542 nsrr = find_ns(nsrrsp, ns_rr_name(rr)); 543 if (nsrr == NULL) { 544 nsrr = malloc(sizeof *nsrr); 545 if (nsrr == NULL) { 546 DPRINTF(("save_ns: malloc failed")); 547 return (-1); 548 } 549 rdata = ns_rr_rdata(rr); 550 if (ns_name_uncompress(ns_msg_base(*msg), 551 ns_msg_end(*msg), rdata, 552 tname, sizeof tname) < 0) { 553 DPRINTF(("save_ns: ns_name_uncompress failed") 554 ); 555 free(nsrr); 556 return (-1); 557 } 558 nsrr->name = strdup(tname); 559 if (nsrr->name == NULL) { 560 DPRINTF(("save_ns: strdup failed")); 561 free(nsrr); 562 return (-1); 563 } 564 INIT_LINK(nsrr, link); 565 INIT_LIST(nsrr->addrs); 566 nsrr->flags = 0; 567 APPEND(*nsrrsp, nsrr, link); 568 } 569 if (save_a(statp, msg, ns_s_ar, 570 nsrr->name, class, opts, nsrr) < 0) { 571 DPRINTF(("save_ns: save_r('%s', %s) failed", 572 nsrr->name, p_class(class))); 573 return (-1); 574 } 575 } 576 return (0); 577 } 578 579 static int 580 save_a(res_state statp, ns_msg *msg, ns_sect sect, 581 const char *owner, ns_class class, int opts, 582 rr_ns *nsrr) 583 { 584 int i; 585 586 for (i = 0; i < ns_msg_count(*msg, sect); i++) { 587 ns_rr rr; 588 rr_a *arr; 589 590 if (ns_parserr(msg, sect, i, &rr) < 0) { 591 DPRINTF(("save_a: ns_parserr(%s, %d) failed", 592 p_section(sect, ns_o_query), i)); 593 return (-1); 594 } 595 if ((ns_rr_type(rr) != ns_t_a && 596 ns_rr_type(rr) != ns_t_aaaa) || 597 ns_rr_class(rr) != class || 598 ns_samename(ns_rr_name(rr), owner) != 1 || 599 ns_rr_rdlen(rr) != NS_INADDRSZ) 600 continue; 601 if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa) 602 continue; 603 if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a) 604 continue; 605 arr = malloc(sizeof *arr); 606 if (arr == NULL) { 607 DPRINTF(("save_a: malloc failed")); 608 return (-1); 609 } 610 INIT_LINK(arr, link); 611 memset(&arr->addr, 0, sizeof(arr->addr)); 612 switch (ns_rr_type(rr)) { 613 case ns_t_a: 614 arr->addr.sin.sin_family = AF_INET; 615 #ifdef HAVE_SA_LEN 616 arr->addr.sin.sin_len = sizeof(arr->addr.sin); 617 #endif 618 memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr), 619 NS_INADDRSZ); 620 arr->addr.sin.sin_port = htons(NAMESERVER_PORT); 621 nsrr->flags |= RR_NS_HAVE_V4; 622 break; 623 case ns_t_aaaa: 624 arr->addr.sin6.sin6_family = AF_INET6; 625 #ifdef HAVE_SA_LEN 626 arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6); 627 #endif 628 memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16); 629 arr->addr.sin6.sin6_port = htons(NAMESERVER_PORT); 630 nsrr->flags |= RR_NS_HAVE_V6; 631 break; 632 default: 633 abort(); 634 } 635 APPEND(nsrr->addrs, arr, link); 636 } 637 return (0); 638 } 639 640 static void 641 free_nsrrset(rrset_ns *nsrrsp) { 642 rr_ns *nsrr; 643 644 while ((nsrr = HEAD(*nsrrsp)) != NULL) 645 free_nsrr(nsrrsp, nsrr); 646 } 647 648 static void 649 free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) { 650 rr_a *arr; 651 char *tmp; 652 653 while ((arr = HEAD(nsrr->addrs)) != NULL) { 654 UNLINK(nsrr->addrs, arr, link); 655 free(arr); 656 } 657 DE_CONST(nsrr->name, tmp); 658 free(tmp); 659 UNLINK(*nsrrsp, nsrr, link); 660 free(nsrr); 661 } 662 663 static rr_ns * 664 find_ns(rrset_ns *nsrrsp, const char *dname) { 665 rr_ns *nsrr; 666 667 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link)) 668 if (ns_samename(nsrr->name, dname) == 1) 669 return (nsrr); 670 return (NULL); 671 } 672 673 static int 674 do_query(res_state statp, const char *dname, ns_class class, ns_type qtype, 675 u_char *resp, ns_msg *msg) 676 { 677 u_char req[NS_PACKETSZ]; 678 int i, n; 679 680 n = res_nmkquery(statp, ns_o_query, dname, class, qtype, 681 NULL, 0, NULL, req, NS_PACKETSZ); 682 if (n < 0) { 683 DPRINTF(("do_query: res_nmkquery failed")); 684 return (-1); 685 } 686 n = res_nsend(statp, req, n, resp, NS_MAXMSG); 687 if (n < 0) { 688 DPRINTF(("do_query: res_nsend failed")); 689 return (-1); 690 } 691 if (n == 0) { 692 DPRINTF(("do_query: res_nsend returned 0")); 693 errno = EMSGSIZE; 694 return (-1); 695 } 696 if (ns_initparse(resp, n, msg) < 0) { 697 DPRINTF(("do_query: ns_initparse failed")); 698 return (-1); 699 } 700 n = 0; 701 for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) { 702 ns_rr rr; 703 704 if (ns_parserr(msg, ns_s_an, i, &rr) < 0) { 705 DPRINTF(("do_query: ns_parserr failed")); 706 return (-1); 707 } 708 n += (ns_rr_class(rr) == class && 709 (ns_rr_type(rr) == ns_t_cname || 710 ns_rr_type(rr) == ns_t_dname)); 711 } 712 return (n); 713 } 714 715 static void 716 res_dprintf(const char *fmt, ...) { 717 va_list ap; 718 719 va_start(ap, fmt); 720 fputs(";; res_findzonecut: ", stderr); 721 vfprintf(stderr, fmt, ap); 722 fputc('\n', stderr); 723 va_end(ap); 724 } 725 726 /*! \file */ 727