1 /* 2 * Copyright 2003 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 #pragma ident "%Z%%M% %I% %E% SMI" 7 8 #if !defined(lint) && !defined(SABER) 9 static const char rcsid[] = "$Id: res_findzonecut.c,v 8.20 2003/05/27 23:36:53 marka Exp $"; 10 #endif /* not lint */ 11 12 /* 13 * Copyright (c) 1999 by Internet Software Consortium. 14 * 15 * Permission to use, copy, modify, and distribute this software for any 16 * purpose with or without fee is hereby granted, provided that the above 17 * copyright notice and this permission notice appear in all copies. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 20 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 22 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 23 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 24 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 25 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 26 * SOFTWARE. 27 */ 28 29 /* Import. */ 30 31 #include "port_before.h" 32 33 #include <sys/param.h> 34 #include <sys/socket.h> 35 #include <sys/time.h> 36 37 #include <netinet/in.h> 38 #include <arpa/inet.h> 39 #include <arpa/nameser.h> 40 41 #include <errno.h> 42 #include <limits.h> 43 #include <netdb.h> 44 #include <stdarg.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 49 #include <isc/list.h> 50 51 #include "port_after.h" 52 53 #include <resolv.h> 54 55 /* Data structures. */ 56 57 typedef struct rr_a { 58 LINK(struct rr_a) link; 59 union res_sockaddr_union addr; 60 } rr_a; 61 typedef LIST(rr_a) rrset_a; 62 63 typedef struct rr_ns { 64 LINK(struct rr_ns) link; 65 const char * name; 66 unsigned int flags; 67 rrset_a addrs; 68 } rr_ns; 69 typedef LIST(rr_ns) rrset_ns; 70 71 #define RR_NS_HAVE_V4 0x01 72 #define RR_NS_HAVE_V6 0x02 73 74 /* Forward. */ 75 76 static int satisfy(res_state, const char *, rrset_ns *, 77 union res_sockaddr_union *, int); 78 static int add_addrs(res_state, rr_ns *, 79 union res_sockaddr_union *, int); 80 static int get_soa(res_state, const char *, ns_class, int, 81 char *, size_t, char *, size_t, 82 rrset_ns *); 83 static int get_ns(res_state, const char *, ns_class, int, rrset_ns *); 84 static int get_glue(res_state, ns_class, int, rrset_ns *); 85 static int save_ns(res_state, ns_msg *, ns_sect, 86 const char *, ns_class, int, rrset_ns *); 87 static int save_a(res_state, ns_msg *, ns_sect, 88 const char *, ns_class, int, rr_ns *); 89 static void free_nsrrset(rrset_ns *); 90 static void free_nsrr(rrset_ns *, rr_ns *); 91 static rr_ns * find_ns(rrset_ns *, const char *); 92 static int do_query(res_state, const char *, ns_class, ns_type, 93 u_char *, ns_msg *); 94 static void res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2); 95 96 /* Macros. */ 97 98 #define DPRINTF(x) do {\ 99 int save_errno = errno; \ 100 if ((statp->options & RES_DEBUG) != 0) res_dprintf x; \ 101 errno = save_errno; \ 102 } while (0) 103 104 /* Public. */ 105 106 /* 107 * int 108 * res_findzonecut(res, dname, class, zname, zsize, addrs, naddrs) 109 * find enclosing zone for a <dname,class>, and some server addresses 110 * parameters: 111 * res - resolver context to work within (is modified) 112 * dname - domain name whose enclosing zone is desired 113 * class - class of dname (and its enclosing zone) 114 * zname - found zone name 115 * zsize - allocated size of zname 116 * addrs - found server addresses 117 * naddrs - max number of addrs 118 * return values: 119 * < 0 - an error occurred (check errno) 120 * = 0 - zname is now valid, but addrs[] wasn't changed 121 * > 0 - zname is now valid, and return value is number of addrs[] found 122 * notes: 123 * this function calls res_nsend() which means it depends on correctly 124 * functioning recursive nameservers (usually defined in /etc/resolv.conf 125 * or its local equivilent). 126 * 127 * we start by asking for an SOA<dname,class>. if we get one as an 128 * answer, that just means <dname,class> is a zone top, which is fine. 129 * more than likely we'll be told to go pound sand, in the form of a 130 * negative answer. 131 * 132 * note that we are not prepared to deal with referrals since that would 133 * only come from authority servers and our correctly functioning local 134 * recursive server would have followed the referral and got us something 135 * more definite. 136 * 137 * if the authority section contains an SOA, this SOA should also be the 138 * closest enclosing zone, since any intermediary zone cuts would've been 139 * returned as referrals and dealt with by our correctly functioning local 140 * recursive name server. but an SOA in the authority section should NOT 141 * match our dname (since that would have been returned in the answer 142 * section). an authority section SOA has to be "above" our dname. 143 * 144 * however, since authority section SOA's were once optional, it's 145 * possible that we'll have to go hunting for the enclosing SOA by 146 * ripping labels off the front of our dname -- this is known as "doing 147 * it the hard way." 148 * 149 * ultimately we want some server addresses, which are ideally the ones 150 * pertaining to the SOA.MNAME, but only if there is a matching NS RR. 151 * so the second phase (after we find an SOA) is to go looking for the 152 * NS RRset for that SOA's zone. 153 * 154 * no answer section processed by this code is allowed to contain CNAME 155 * or DNAME RR's. for the SOA query this means we strip a label and 156 * keep going. for the NS and A queries this means we just give up. 157 */ 158 159 int 160 res_findzonecut(res_state statp, const char *dname, ns_class class, int opts, 161 char *zname, size_t zsize, struct in_addr *addrs, int naddrs) 162 { 163 int result, i; 164 union res_sockaddr_union *u; 165 166 167 opts |= RES_IPV4ONLY; 168 opts &= ~RES_IPV6ONLY; 169 170 u = calloc(naddrs, sizeof(*u)); 171 if (u == NULL) 172 return(-1); 173 174 result = res_findzonecut2(statp, dname, class, opts, zname, zsize, 175 u, naddrs); 176 177 for (i = 0; i < result; i++) { 178 addrs[i] = u[i].sin.sin_addr; 179 } 180 free(u); 181 return (result); 182 } 183 184 int 185 res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts, 186 char *zname, size_t zsize, union res_sockaddr_union *addrs, 187 int naddrs) 188 { 189 char mname[NS_MAXDNAME]; 190 u_long save_pfcode; 191 rrset_ns nsrrs; 192 int n; 193 194 DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d", 195 dname, p_class(class), (long)zsize, naddrs)); 196 save_pfcode = statp->pfcode; 197 statp->pfcode |= RES_PRF_HEAD2 | RES_PRF_HEAD1 | RES_PRF_HEADX | 198 RES_PRF_QUES | RES_PRF_ANS | 199 RES_PRF_AUTH | RES_PRF_ADD; 200 INIT_LIST(nsrrs); 201 202 DPRINTF(("get the soa, and see if it has enough glue")); 203 if ((n = get_soa(statp, dname, class, opts, zname, zsize, 204 mname, sizeof mname, &nsrrs)) < 0 || 205 ((opts & RES_EXHAUSTIVE) == 0 && 206 (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0)) 207 goto done; 208 209 DPRINTF(("get the ns rrset and see if it has enough glue")); 210 if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 || 211 ((opts & RES_EXHAUSTIVE) == 0 && 212 (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0)) 213 goto done; 214 215 DPRINTF(("get the missing glue and see if it's finally enough")); 216 if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0) 217 n = satisfy(statp, mname, &nsrrs, addrs, naddrs); 218 219 done: 220 DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK")); 221 free_nsrrset(&nsrrs); 222 statp->pfcode = save_pfcode; 223 return (n); 224 } 225 226 /* Private. */ 227 228 static int 229 satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp, 230 union res_sockaddr_union *addrs, int naddrs) 231 { 232 rr_ns *nsrr; 233 int n, x; 234 235 n = 0; 236 nsrr = find_ns(nsrrsp, mname); 237 if (nsrr != NULL) { 238 x = add_addrs(statp, nsrr, addrs, naddrs); 239 addrs += x; 240 naddrs -= x; 241 n += x; 242 } 243 for (nsrr = HEAD(*nsrrsp); 244 nsrr != NULL && naddrs > 0; 245 nsrr = NEXT(nsrr, link)) 246 if (ns_samename(nsrr->name, mname) != 1) { 247 x = add_addrs(statp, nsrr, addrs, naddrs); 248 addrs += x; 249 naddrs -= x; 250 n += x; 251 } 252 DPRINTF(("satisfy(%s): %d", mname, n)); 253 return (n); 254 } 255 256 static int 257 add_addrs(res_state statp, rr_ns *nsrr, 258 union res_sockaddr_union *addrs, int naddrs) 259 { 260 rr_a *arr; 261 int n = 0; 262 263 for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) { 264 if (naddrs <= 0) 265 return (0); 266 *addrs++ = arr->addr; 267 naddrs--; 268 n++; 269 } 270 DPRINTF(("add_addrs: %d", n)); 271 return (n); 272 } 273 274 static int 275 get_soa(res_state statp, const char *dname, ns_class class, int opts, 276 char *zname, size_t zsize, char *mname, size_t msize, 277 rrset_ns *nsrrsp) 278 { 279 char tname[NS_MAXDNAME]; 280 u_char *resp = NULL; 281 int n, i, ancount, nscount; 282 ns_sect sect; 283 ns_msg msg; 284 u_int rcode; 285 286 /* 287 * Find closest enclosing SOA, even if it's for the root zone. 288 */ 289 290 /* First canonicalize dname (exactly one unescaped trailing "."). */ 291 if (ns_makecanon(dname, tname, sizeof tname) < 0) 292 goto cleanup; 293 dname = tname; 294 295 resp = malloc(NS_MAXMSG); 296 if (resp == NULL) 297 goto cleanup; 298 299 /* Now grovel the subdomains, hunting for an SOA answer or auth. */ 300 for (;;) { 301 /* Leading or inter-label '.' are skipped here. */ 302 while (*dname == '.') 303 dname++; 304 305 /* Is there an SOA? */ 306 n = do_query(statp, dname, class, ns_t_soa, resp, &msg); 307 if (n < 0) { 308 DPRINTF(("get_soa: do_query('%s', %s) failed (%d)", 309 dname, p_class(class), n)); 310 goto cleanup; 311 } 312 if (n > 0) { 313 DPRINTF(("get_soa: CNAME or DNAME found")); 314 sect = ns_s_max, n = 0; 315 } else { 316 rcode = ns_msg_getflag(msg, ns_f_rcode); 317 ancount = ns_msg_count(msg, ns_s_an); 318 nscount = ns_msg_count(msg, ns_s_ns); 319 if (ancount > 0 && rcode == ns_r_noerror) 320 sect = ns_s_an, n = ancount; 321 else if (nscount > 0) 322 sect = ns_s_ns, n = nscount; 323 else 324 sect = ns_s_max, n = 0; 325 } 326 for (i = 0; i < n; i++) { 327 const char *t; 328 const u_char *rdata; 329 int rdlen; 330 ns_rr rr; 331 332 if (ns_parserr(&msg, sect, i, &rr) < 0) { 333 DPRINTF(("get_soa: ns_parserr(%s, %d) failed", 334 p_section(sect, ns_o_query), i)); 335 goto cleanup; 336 } 337 if (ns_rr_type(rr) == ns_t_cname || 338 ns_rr_type(rr) == ns_t_dname) 339 break; 340 if (ns_rr_type(rr) != ns_t_soa || 341 ns_rr_class(rr) != class) 342 continue; 343 t = ns_rr_name(rr); 344 switch (sect) { 345 case ns_s_an: 346 if (ns_samedomain(dname, t) == 0) { 347 DPRINTF( 348 ("get_soa: ns_samedomain('%s', '%s') == 0", 349 dname, t) 350 ); 351 errno = EPROTOTYPE; 352 goto cleanup; 353 } 354 break; 355 case ns_s_ns: 356 if (ns_samename(dname, t) == 1 || 357 ns_samedomain(dname, t) == 0) { 358 DPRINTF( 359 ("get_soa: ns_samename() || !ns_samedomain('%s', '%s')", 360 dname, t) 361 ); 362 errno = EPROTOTYPE; 363 goto cleanup; 364 } 365 break; 366 default: 367 abort(); 368 } 369 if (strlen(t) + 1 > zsize) { 370 DPRINTF(("get_soa: zname(%d) too small (%d)", 371 zsize, strlen(t) + 1)); 372 errno = EMSGSIZE; 373 goto cleanup; 374 } 375 strcpy(zname, t); 376 rdata = ns_rr_rdata(rr); 377 rdlen = ns_rr_rdlen(rr); 378 if (ns_name_uncompress(resp, ns_msg_end(msg), rdata, 379 mname, msize) < 0) { 380 DPRINTF(("get_soa: ns_name_uncompress failed") 381 ); 382 goto cleanup; 383 } 384 if (save_ns(statp, &msg, ns_s_ns, 385 zname, class, opts, nsrrsp) < 0) { 386 DPRINTF(("get_soa: save_ns failed")); 387 goto cleanup; 388 } 389 free(resp); 390 return (0); 391 } 392 393 /* If we're out of labels, then not even "." has an SOA! */ 394 if (*dname == '\0') 395 break; 396 397 /* Find label-terminating "."; top of loop will skip it. */ 398 while (*dname != '.') { 399 if (*dname == '\\') 400 if (*++dname == '\0') { 401 errno = EMSGSIZE; 402 goto cleanup; 403 } 404 dname++; 405 } 406 } 407 DPRINTF(("get_soa: out of labels")); 408 errno = EDESTADDRREQ; 409 cleanup: 410 if (resp != NULL) 411 free(resp); 412 return (-1); 413 } 414 415 static int 416 get_ns(res_state statp, const char *zname, ns_class class, int opts, 417 rrset_ns *nsrrsp) 418 { 419 u_char *resp; 420 ns_msg msg; 421 int n; 422 423 resp = malloc(NS_MAXMSG); 424 if (resp == NULL) 425 return (-1); 426 427 /* Go and get the NS RRs for this zone. */ 428 n = do_query(statp, zname, class, ns_t_ns, resp, &msg); 429 if (n != 0) { 430 DPRINTF(("get_ns: do_query('%s', %s) failed (%d)", 431 zname, p_class(class), n)); 432 free(resp); 433 return (-1); 434 } 435 436 /* Remember the NS RRs and associated A RRs that came back. */ 437 if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) { 438 DPRINTF(("get_ns save_ns('%s', %s) failed", 439 zname, p_class(class))); 440 free(resp); 441 return (-1); 442 } 443 444 free(resp); 445 return (0); 446 } 447 448 static int 449 get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) { 450 rr_ns *nsrr, *nsrr_n; 451 u_char *resp; 452 453 resp = malloc(NS_MAXMSG); 454 if (resp == NULL) 455 return(-1); 456 457 /* Go and get the A RRs for each empty NS RR on our list. */ 458 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) { 459 ns_msg msg; 460 int n; 461 462 nsrr_n = NEXT(nsrr, link); 463 464 if ((nsrr->flags & RR_NS_HAVE_V4) == 0) { 465 n = do_query(statp, nsrr->name, class, ns_t_a, 466 resp, &msg); 467 if (n < 0) { 468 DPRINTF( 469 ("get_glue: do_query('%s', %s') failed", 470 nsrr->name, p_class(class))); 471 goto cleanup; 472 } 473 if (n > 0) { 474 DPRINTF(( 475 "get_glue: do_query('%s', %s') CNAME or DNAME found", 476 nsrr->name, p_class(class))); 477 } 478 if (save_a(statp, &msg, ns_s_an, nsrr->name, class, 479 opts, nsrr) < 0) { 480 DPRINTF(("get_glue: save_r('%s', %s) failed", 481 nsrr->name, p_class(class))); 482 goto cleanup; 483 } 484 } 485 486 if ((nsrr->flags & RR_NS_HAVE_V6) == 0) { 487 n = do_query(statp, nsrr->name, class, ns_t_aaaa, 488 resp, &msg); 489 if (n < 0) { 490 DPRINTF( 491 ("get_glue: do_query('%s', %s') failed", 492 nsrr->name, p_class(class))); 493 goto cleanup; 494 } 495 if (n > 0) { 496 DPRINTF(( 497 "get_glue: do_query('%s', %s') CNAME or DNAME found", 498 nsrr->name, p_class(class))); 499 } 500 if (save_a(statp, &msg, ns_s_an, nsrr->name, class, 501 opts, nsrr) < 0) { 502 DPRINTF(("get_glue: save_r('%s', %s) failed", 503 nsrr->name, p_class(class))); 504 goto cleanup; 505 } 506 } 507 508 /* If it's still empty, it's just chaff. */ 509 if (EMPTY(nsrr->addrs)) { 510 DPRINTF(("get_glue: removing empty '%s' NS", 511 nsrr->name)); 512 free_nsrr(nsrrsp, nsrr); 513 } 514 } 515 free(resp); 516 return (0); 517 518 cleanup: 519 free(resp); 520 return (-1); 521 } 522 523 static int 524 save_ns(res_state statp, ns_msg *msg, ns_sect sect, 525 const char *owner, ns_class class, int opts, 526 rrset_ns *nsrrsp) 527 { 528 int i; 529 530 for (i = 0; i < ns_msg_count(*msg, sect); i++) { 531 char tname[MAXDNAME]; 532 const u_char *rdata; 533 rr_ns *nsrr; 534 ns_rr rr; 535 int rdlen; 536 537 if (ns_parserr(msg, sect, i, &rr) < 0) { 538 DPRINTF(("save_ns: ns_parserr(%s, %d) failed", 539 p_section(sect, ns_o_query), i)); 540 return (-1); 541 } 542 if (ns_rr_type(rr) != ns_t_ns || 543 ns_rr_class(rr) != class || 544 ns_samename(ns_rr_name(rr), owner) != 1) 545 continue; 546 nsrr = find_ns(nsrrsp, ns_rr_name(rr)); 547 if (nsrr == NULL) { 548 nsrr = malloc(sizeof *nsrr); 549 if (nsrr == NULL) { 550 DPRINTF(("save_ns: malloc failed")); 551 return (-1); 552 } 553 rdata = ns_rr_rdata(rr); 554 rdlen = ns_rr_rdlen(rr); 555 if (ns_name_uncompress(ns_msg_base(*msg), 556 ns_msg_end(*msg), rdata, 557 tname, sizeof tname) < 0) { 558 DPRINTF(("save_ns: ns_name_uncompress failed") 559 ); 560 free(nsrr); 561 return (-1); 562 } 563 nsrr->name = strdup(tname); 564 if (nsrr->name == NULL) { 565 DPRINTF(("save_ns: strdup failed")); 566 free(nsrr); 567 return (-1); 568 } 569 INIT_LINK(nsrr, link); 570 INIT_LIST(nsrr->addrs); 571 nsrr->flags = 0; 572 APPEND(*nsrrsp, nsrr, link); 573 } 574 if (save_a(statp, msg, ns_s_ar, 575 nsrr->name, class, opts, nsrr) < 0) { 576 DPRINTF(("save_ns: save_r('%s', %s) failed", 577 nsrr->name, p_class(class))); 578 return (-1); 579 } 580 } 581 return (0); 582 } 583 584 static int 585 save_a(res_state statp, ns_msg *msg, ns_sect sect, 586 const char *owner, ns_class class, int opts, 587 rr_ns *nsrr) 588 { 589 int i; 590 591 for (i = 0; i < ns_msg_count(*msg, sect); i++) { 592 ns_rr rr; 593 rr_a *arr; 594 595 if (ns_parserr(msg, sect, i, &rr) < 0) { 596 DPRINTF(("save_a: ns_parserr(%s, %d) failed", 597 p_section(sect, ns_o_query), i)); 598 return (-1); 599 } 600 if ((ns_rr_type(rr) != ns_t_a && 601 ns_rr_type(rr) != ns_t_aaaa) || 602 ns_rr_class(rr) != class || 603 ns_samename(ns_rr_name(rr), owner) != 1 || 604 ns_rr_rdlen(rr) != NS_INADDRSZ) 605 continue; 606 if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa) 607 continue; 608 if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a) 609 continue; 610 arr = malloc(sizeof *arr); 611 if (arr == NULL) { 612 DPRINTF(("save_a: malloc failed")); 613 return (-1); 614 } 615 INIT_LINK(arr, link); 616 memset(&arr->addr, 0, sizeof(arr->addr)); 617 switch (ns_rr_type(rr)) { 618 case ns_t_a: 619 arr->addr.sin.sin_family = AF_INET; 620 #ifdef HAVE_SA_LEN 621 arr->addr.sin.sin_len = sizeof(arr->addr.sin); 622 #endif 623 memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr), 624 NS_INADDRSZ); 625 arr->addr.sin.sin_port = htons(NAMESERVER_PORT); 626 nsrr->flags |= RR_NS_HAVE_V4; 627 break; 628 case ns_t_aaaa: 629 arr->addr.sin6.sin6_family = AF_INET6; 630 #ifdef HAVE_SA_LEN 631 arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6); 632 #endif 633 memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16); 634 arr->addr.sin.sin_port = htons(NAMESERVER_PORT); 635 nsrr->flags |= RR_NS_HAVE_V6; 636 break; 637 default: 638 abort(); 639 } 640 APPEND(nsrr->addrs, arr, link); 641 } 642 return (0); 643 } 644 645 static void 646 free_nsrrset(rrset_ns *nsrrsp) { 647 rr_ns *nsrr; 648 649 while ((nsrr = HEAD(*nsrrsp)) != NULL) 650 free_nsrr(nsrrsp, nsrr); 651 } 652 653 static void 654 free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) { 655 rr_a *arr; 656 char *tmp; 657 658 while ((arr = HEAD(nsrr->addrs)) != NULL) { 659 UNLINK(nsrr->addrs, arr, link); 660 free(arr); 661 } 662 DE_CONST(nsrr->name, tmp); 663 free(tmp); 664 UNLINK(*nsrrsp, nsrr, link); 665 free(nsrr); 666 } 667 668 static rr_ns * 669 find_ns(rrset_ns *nsrrsp, const char *dname) { 670 rr_ns *nsrr; 671 672 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link)) 673 if (ns_samename(nsrr->name, dname) == 1) 674 return (nsrr); 675 return (NULL); 676 } 677 678 static int 679 do_query(res_state statp, const char *dname, ns_class class, ns_type qtype, 680 u_char *resp, ns_msg *msg) 681 { 682 u_char req[NS_PACKETSZ]; 683 int i, n; 684 685 n = res_nmkquery(statp, ns_o_query, dname, class, qtype, 686 NULL, 0, NULL, req, NS_PACKETSZ); 687 if (n < 0) { 688 DPRINTF(("do_query: res_nmkquery failed")); 689 return (-1); 690 } 691 n = res_nsend(statp, req, n, resp, NS_MAXMSG); 692 if (n < 0) { 693 DPRINTF(("do_query: res_nsend failed")); 694 return (-1); 695 } 696 if (n == 0) { 697 DPRINTF(("do_query: res_nsend returned 0")); 698 errno = EMSGSIZE; 699 return (-1); 700 } 701 if (ns_initparse(resp, n, msg) < 0) { 702 DPRINTF(("do_query: ns_initparse failed")); 703 return (-1); 704 } 705 n = 0; 706 for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) { 707 ns_rr rr; 708 709 if (ns_parserr(msg, ns_s_an, i, &rr) < 0) { 710 DPRINTF(("do_query: ns_parserr failed")); 711 return (-1); 712 } 713 n += (ns_rr_class(rr) == class && 714 (ns_rr_type(rr) == ns_t_cname || 715 ns_rr_type(rr) == ns_t_dname)); 716 } 717 return (n); 718 } 719 720 static void 721 res_dprintf(const char *fmt, ...) { 722 va_list ap; 723 724 va_start(ap, fmt); 725 fputs(";; res_findzonecut: ", stderr); 726 vfprintf(stderr, fmt, ap); 727 fputc('\n', stderr); 728 va_end(ap); 729 } 730