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