contrib/bind-9.3/lib/bind/resolv/res_findzonecut.c

   1 #if !defined(lint) && !defined(SABER)
   2 static const char rcsid[] = "$Id: res_findzonecut.c,v 1.2.2.3.4.4 2005/10/11 00:48:16 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  * int
 101  * res_findzonecut(res, dname, class, zname, zsize, addrs, naddrs)
 102  *      find enclosing zone for a <dname,class>, and some server addresses
 103  * parameters:
 104  *      res - resolver context to work within (is modified)
 105  *      dname - domain name whose enclosing zone is desired
 106  *      class - class of dname (and its enclosing zone)
 107  *      zname - found zone name
 108  *      zsize - allocated size of zname
 109  *      addrs - found server addresses
 110  *      naddrs - max number of addrs
 111  * return values:
 112  *      < 0 - an error occurred (check errno)
 113  *      = 0 - zname is now valid, but addrs[] wasn't changed
 114  *      > 0 - zname is now valid, and return value is number of addrs[] found
 115  * notes:
 116  *      this function calls res_nsend() which means it depends on correctly
 117  *      functioning recursive nameservers (usually defined in /etc/resolv.conf
 118  *      or its local equivilent).
 119  *
 120  *      we start by asking for an SOA<dname,class>.  if we get one as an
 121  *      answer, that just means <dname,class> is a zone top, which is fine.
 122  *      more than likely we'll be told to go pound sand, in the form of a
 123  *      negative answer.
 124  *
 125  *      note that we are not prepared to deal with referrals since that would
 126  *      only come from authority servers and our correctly functioning local
 127  *      recursive server would have followed the referral and got us something
 128  *      more definite.
 129  *
 130  *      if the authority section contains an SOA, this SOA should also be the
 131  *      closest enclosing zone, since any intermediary zone cuts would've been
 132  *      returned as referrals and dealt with by our correctly functioning local
 133  *      recursive name server.  but an SOA in the authority section should NOT
 134  *      match our dname (since that would have been returned in the answer
 135  *      section).  an authority section SOA has to be "above" our dname.
 136  *
 137  *      however, since authority section SOA's were once optional, it's
 138  *      possible that we'll have to go hunting for the enclosing SOA by
 139  *      ripping labels off the front of our dname -- this is known as "doing
 140  *      it the hard way."
 141  *
 142  *      ultimately we want some server addresses, which are ideally the ones
 143  *      pertaining to the SOA.MNAME, but only if there is a matching NS RR.
 144  *      so the second phase (after we find an SOA) is to go looking for the
 145  *      NS RRset for that SOA's zone.
 146  *
 147  *      no answer section processed by this code is allowed to contain CNAME
 148  *      or DNAME RR's.  for the SOA query this means we strip a label and
 149  *      keep going.  for the NS and A queries this means we just give up.
 150  */
 151
 152 int
 153 res_findzonecut(res_state statp, const char *dname, ns_class class, int opts,
 154                 char *zname, size_t zsize, struct in_addr *addrs, int naddrs)
 155 {
 156         int result, i;
 157         union res_sockaddr_union *u;
 158
 159
 160         opts |= RES_IPV4ONLY;
 161         opts &= ~RES_IPV6ONLY;
 162
 163         u = calloc(naddrs, sizeof(*u));
 164         if (u == NULL)
 165                 return(-1);
 166
 167         result = res_findzonecut2(statp, dname, class, opts, zname, zsize,
 168                                   u, naddrs);
 169
 170         for (i = 0; i < result; i++) {
 171                 addrs[i] = u[i].sin.sin_addr;
 172         }
 173         free(u);
 174         return (result);
 175 }
 176
 177 int
 178 res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts,
 179                  char *zname, size_t zsize, union res_sockaddr_union *addrs,
 180                  int naddrs)
 181 {
 182         char mname[NS_MAXDNAME];
 183         u_long save_pfcode;
 184         rrset_ns nsrrs;
 185         int n;
 186
 187         DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d",
 188                  dname, p_class(class), (long)zsize, naddrs));
 189         save_pfcode = statp->pfcode;
 190         statp->pfcode |= RES_PRF_HEAD2 | RES_PRF_HEAD1 | RES_PRF_HEADX |
 191                          RES_PRF_QUES | RES_PRF_ANS |
 192                          RES_PRF_AUTH | RES_PRF_ADD;
 193         INIT_LIST(nsrrs);
 194
 195         DPRINTF(("get the soa, and see if it has enough glue"));
 196         if ((n = get_soa(statp, dname, class, opts, zname, zsize,
 197                          mname, sizeof mname, &nsrrs)) < 0 ||
 198             ((opts & RES_EXHAUSTIVE) == 0 &&
 199              (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
 200                 goto done;
 201
 202         DPRINTF(("get the ns rrset and see if it has enough glue"));
 203         if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 ||
 204             ((opts & RES_EXHAUSTIVE) == 0 &&
 205              (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
 206                 goto done;
 207
 208         DPRINTF(("get the missing glue and see if it's finally enough"));
 209         if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0)
 210                 n = satisfy(statp, mname, &nsrrs, addrs, naddrs);
 211
 212  done:
 213         DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK"));
 214         free_nsrrset(&nsrrs);
 215         statp->pfcode = save_pfcode;
 216         return (n);
 217 }
 218
 219 /* Private. */
 220
 221 static int
 222 satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp,
 223         union res_sockaddr_union *addrs, int naddrs)
 224 {
 225         rr_ns *nsrr;
 226         int n, x;
 227
 228         n = 0;
 229         nsrr = find_ns(nsrrsp, mname);
 230         if (nsrr != NULL) {
 231                 x = add_addrs(statp, nsrr, addrs, naddrs);
 232                 addrs += x;
 233                 naddrs -= x;
 234                 n += x;
 235         }
 236         for (nsrr = HEAD(*nsrrsp);
 237              nsrr != NULL && naddrs > 0;
 238              nsrr = NEXT(nsrr, link))
 239                 if (ns_samename(nsrr->name, mname) != 1) {
 240                         x = add_addrs(statp, nsrr, addrs, naddrs);
 241                         addrs += x;
 242                         naddrs -= x;
 243                         n += x;
 244                 }
 245         DPRINTF(("satisfy(%s): %d", mname, n));
 246         return (n);
 247 }
 248
 249 static int
 250 add_addrs(res_state statp, rr_ns *nsrr,
 251           union res_sockaddr_union *addrs, int naddrs)
 252 {
 253         rr_a *arr;
 254         int n = 0;
 255
 256         for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) {
 257                 if (naddrs <= 0)
 258                         return (0);
 259                 *addrs++ = arr->addr;
 260                 naddrs--;
 261                 n++;
 262         }
 263         DPRINTF(("add_addrs: %d", n));
 264         return (n);
 265 }
 266
 267 static int
 268 get_soa(res_state statp, const char *dname, ns_class class, int opts,
 269         char *zname, size_t zsize, char *mname, size_t msize,
 270         rrset_ns *nsrrsp)
 271 {
 272         char tname[NS_MAXDNAME];
 273         u_char *resp = NULL;
 274         int n, i, ancount, nscount;
 275         ns_sect sect;
 276         ns_msg msg;
 277         u_int rcode;
 278
 279         /*
 280          * Find closest enclosing SOA, even if it's for the root zone.
 281          */
 282
 283         /* First canonicalize dname (exactly one unescaped trailing "."). */
 284         if (ns_makecanon(dname, tname, sizeof tname) < 0)
 285                 goto cleanup;
 286         dname = tname;
 287
 288         resp = malloc(NS_MAXMSG);
 289         if (resp == NULL)
 290                 goto cleanup;
 291
 292         /* Now grovel the subdomains, hunting for an SOA answer or auth. */
 293         for (;;) {
 294                 /* Leading or inter-label '.' are skipped here. */
 295                 while (*dname == '.')
 296                         dname++;
 297
 298                 /* Is there an SOA? */
 299                 n = do_query(statp, dname, class, ns_t_soa, resp, &msg);
 300                 if (n < 0) {
 301                         DPRINTF(("get_soa: do_query('%s', %s) failed (%d)",
 302                                  dname, p_class(class), n));
 303                         goto cleanup;
 304                 }
 305                 if (n > 0) {
 306                         DPRINTF(("get_soa: CNAME or DNAME found"));
 307                         sect = ns_s_max, n = 0;
 308                 } else {
 309                         rcode = ns_msg_getflag(msg, ns_f_rcode);
 310                         ancount = ns_msg_count(msg, ns_s_an);
 311                         nscount = ns_msg_count(msg, ns_s_ns);
 312                         if (ancount > 0 && rcode == ns_r_noerror)
 313                                 sect = ns_s_an, n = ancount;
 314                         else if (nscount > 0)
 315                                 sect = ns_s_ns, n = nscount;
 316                         else
 317                                 sect = ns_s_max, n = 0;
 318                 }
 319                 for (i = 0; i < n; i++) {
 320                         const char *t;
 321                         const u_char *rdata;
 322                         ns_rr rr;
 323
 324                         if (ns_parserr(&msg, sect, i, &rr) < 0) {
 325                                 DPRINTF(("get_soa: ns_parserr(%s, %d) failed",
 326                                          p_section(sect, ns_o_query), i));
 327                                 goto cleanup;
 328                         }
 329                         if (ns_rr_type(rr) == ns_t_cname ||
 330                             ns_rr_type(rr) == ns_t_dname)
 331                                 break;
 332                         if (ns_rr_type(rr) != ns_t_soa ||
 333                             ns_rr_class(rr) != class)
 334                                 continue;
 335                         t = ns_rr_name(rr);
 336                         switch (sect) {
 337                         case ns_s_an:
 338                                 if (ns_samedomain(dname, t) == 0) {
 339                                         DPRINTF(
 340                                     ("get_soa: ns_samedomain('%s', '%s') == 0",
 341                                                 dname, t)
 342                                                 );
 343                                         errno = EPROTOTYPE;
 344                                         goto cleanup;
 345                                 }
 346                                 break;
 347                         case ns_s_ns:
 348                                 if (ns_samename(dname, t) == 1 ||
 349                                     ns_samedomain(dname, t) == 0) {
 350                                         DPRINTF(
 351                        ("get_soa: ns_samename() || !ns_samedomain('%s', '%s')",
 352                                                 dname, t)
 353                                                 );
 354                                         errno = EPROTOTYPE;
 355                                         goto cleanup;
 356                                 }
 357                                 break;
 358                         default:
 359                                 abort();
 360                         }
 361                         if (strlen(t) + 1 > zsize) {
 362                                 DPRINTF(("get_soa: zname(%lu) too small (%lu)",
 363                                          (unsigned long)zsize,
 364                                          (unsigned long)strlen(t) + 1));
 365                                 errno = EMSGSIZE;
 366                                 goto cleanup;
 367                         }
 368                         strcpy(zname, t);
 369                         rdata = ns_rr_rdata(rr);
 370                         if (ns_name_uncompress(resp, ns_msg_end(msg), rdata,
 371                                                mname, msize) < 0) {
 372                                 DPRINTF(("get_soa: ns_name_uncompress failed")
 373                                         );
 374                                 goto cleanup;
 375                         }
 376                         if (save_ns(statp, &msg, ns_s_ns,
 377                                     zname, class, opts, nsrrsp) < 0) {
 378                                 DPRINTF(("get_soa: save_ns failed"));
 379                                 goto cleanup;
 380                         }
 381                         free(resp);
 382                         return (0);
 383                 }
 384
 385                 /* If we're out of labels, then not even "." has an SOA! */
 386                 if (*dname == '\0')
 387                         break;
 388
 389                 /* Find label-terminating "."; top of loop will skip it. */
 390                 while (*dname != '.') {
 391                         if (*dname == '\\')
 392                                 if (*++dname == '\0') {
 393                                         errno = EMSGSIZE;
 394                                         goto cleanup;
 395                                 }
 396                         dname++;
 397                 }
 398         }
 399         DPRINTF(("get_soa: out of labels"));
 400         errno = EDESTADDRREQ;
 401  cleanup:
 402         if (resp != NULL)
 403                 free(resp);
 404         return (-1);
 405 }
 406
 407 static int
 408 get_ns(res_state statp, const char *zname, ns_class class, int opts,
 409       rrset_ns *nsrrsp)
 410 {
 411         u_char *resp;
 412         ns_msg msg;
 413         int n;
 414
 415         resp = malloc(NS_MAXMSG);
 416         if (resp == NULL)
 417                 return (-1);
 418
 419         /* Go and get the NS RRs for this zone. */
 420         n = do_query(statp, zname, class, ns_t_ns, resp, &msg);
 421         if (n != 0) {
 422                 DPRINTF(("get_ns: do_query('%s', %s) failed (%d)",
 423                          zname, p_class(class), n));
 424                 free(resp);
 425                 return (-1);
 426         }
 427
 428         /* Remember the NS RRs and associated A RRs that came back. */
 429         if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) {
 430                 DPRINTF(("get_ns save_ns('%s', %s) failed",
 431                          zname, p_class(class)));
 432                 free(resp);
 433                 return (-1);
 434         }
 435
 436         free(resp);
 437         return (0);
 438 }
 439
 440 static int
 441 get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) {
 442         rr_ns *nsrr, *nsrr_n;
 443         u_char *resp;
 444
 445         resp = malloc(NS_MAXMSG);
 446         if (resp == NULL)
 447                 return(-1);
 448
 449         /* Go and get the A RRs for each empty NS RR on our list. */
 450         for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) {
 451                 ns_msg msg;
 452                 int n;
 453
 454                 nsrr_n = NEXT(nsrr, link);
 455
 456                 if ((nsrr->flags & RR_NS_HAVE_V4) == 0) {
 457                         n = do_query(statp, nsrr->name, class, ns_t_a,
 458                                      resp, &msg);
 459                         if (n < 0) {
 460                                 DPRINTF(
 461                                        ("get_glue: do_query('%s', %s') failed",
 462                                         nsrr->name, p_class(class)));
 463                                 goto cleanup;
 464                         }
 465                         if (n > 0) {
 466                                 DPRINTF((
 467                         "get_glue: do_query('%s', %s') CNAME or DNAME found",
 468                                          nsrr->name, p_class(class)));
 469                         }
 470                         if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
 471                                    opts, nsrr) < 0) {
 472                                 DPRINTF(("get_glue: save_r('%s', %s) failed",
 473                                          nsrr->name, p_class(class)));
 474                                 goto cleanup;
 475                         }
 476                 }
 477
 478                 if ((nsrr->flags & RR_NS_HAVE_V6) == 0) {
 479                         n = do_query(statp, nsrr->name, class, ns_t_aaaa,
 480                                      resp, &msg);
 481                         if (n < 0) {
 482                                 DPRINTF(
 483                                        ("get_glue: do_query('%s', %s') failed",
 484                                         nsrr->name, p_class(class)));
 485                                 goto cleanup;
 486                         }
 487                         if (n > 0) {
 488                                 DPRINTF((
 489                         "get_glue: do_query('%s', %s') CNAME or DNAME found",
 490                                          nsrr->name, p_class(class)));
 491                         }
 492                         if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
 493                                    opts, nsrr) < 0) {
 494                                 DPRINTF(("get_glue: save_r('%s', %s) failed",
 495                                          nsrr->name, p_class(class)));
 496                                 goto cleanup;
 497                         }
 498                 }
 499
 500                 /* If it's still empty, it's just chaff. */
 501                 if (EMPTY(nsrr->addrs)) {
 502                         DPRINTF(("get_glue: removing empty '%s' NS",
 503                                  nsrr->name));
 504                         free_nsrr(nsrrsp, nsrr);
 505                 }
 506         }
 507         free(resp);
 508         return (0);
 509
 510  cleanup:
 511         free(resp);
 512         return (-1);
 513 }
 514
 515 static int
 516 save_ns(res_state statp, ns_msg *msg, ns_sect sect,
 517         const char *owner, ns_class class, int opts,
 518         rrset_ns *nsrrsp)
 519 {
 520         int i;
 521
 522         for (i = 0; i < ns_msg_count(*msg, sect); i++) {
 523                 char tname[MAXDNAME];
 524                 const u_char *rdata;
 525                 rr_ns *nsrr;
 526                 ns_rr rr;
 527
 528                 if (ns_parserr(msg, sect, i, &rr) < 0) {
 529                         DPRINTF(("save_ns: ns_parserr(%s, %d) failed",
 530                                  p_section(sect, ns_o_query), i));
 531                         return (-1);
 532                 }
 533                 if (ns_rr_type(rr) != ns_t_ns ||
 534                     ns_rr_class(rr) != class ||
 535                     ns_samename(ns_rr_name(rr), owner) != 1)
 536                         continue;
 537                 nsrr = find_ns(nsrrsp, ns_rr_name(rr));
 538                 if (nsrr == NULL) {
 539                         nsrr = malloc(sizeof *nsrr);
 540                         if (nsrr == NULL) {
 541                                 DPRINTF(("save_ns: malloc failed"));
 542                                 return (-1);
 543                         }
 544                         rdata = ns_rr_rdata(rr);
 545                         if (ns_name_uncompress(ns_msg_base(*msg),
 546                                                ns_msg_end(*msg), rdata,
 547                                                tname, sizeof tname) < 0) {
 548                                 DPRINTF(("save_ns: ns_name_uncompress failed")
 549                                         );
 550                                 free(nsrr);
 551                                 return (-1);
 552                         }
 553                         nsrr->name = strdup(tname);
 554                         if (nsrr->name == NULL) {
 555                                 DPRINTF(("save_ns: strdup failed"));
 556                                 free(nsrr);
 557                                 return (-1);
 558                         }
 559                         INIT_LINK(nsrr, link);
 560                         INIT_LIST(nsrr->addrs);
 561                         nsrr->flags = 0;
 562                         APPEND(*nsrrsp, nsrr, link);
 563                 }
 564                 if (save_a(statp, msg, ns_s_ar,
 565                            nsrr->name, class, opts, nsrr) < 0) {
 566                         DPRINTF(("save_ns: save_r('%s', %s) failed",
 567                                  nsrr->name, p_class(class)));
 568                         return (-1);
 569                 }
 570         }
 571         return (0);
 572 }
 573
 574 static int
 575 save_a(res_state statp, ns_msg *msg, ns_sect sect,
 576        const char *owner, ns_class class, int opts,
 577        rr_ns *nsrr)
 578 {
 579         int i;
 580
 581         for (i = 0; i < ns_msg_count(*msg, sect); i++) {
 582                 ns_rr rr;
 583                 rr_a *arr;
 584
 585                 if (ns_parserr(msg, sect, i, &rr) < 0) {
 586                         DPRINTF(("save_a: ns_parserr(%s, %d) failed",
 587                                  p_section(sect, ns_o_query), i));
 588                         return (-1);
 589                 }
 590                 if ((ns_rr_type(rr) != ns_t_a &&
 591                      ns_rr_type(rr) != ns_t_aaaa) ||
 592                     ns_rr_class(rr) != class ||
 593                     ns_samename(ns_rr_name(rr), owner) != 1 ||
 594                     ns_rr_rdlen(rr) != NS_INADDRSZ)
 595                         continue;
 596                 if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa)
 597                         continue;
 598                 if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a)
 599                         continue;
 600                 arr = malloc(sizeof *arr);
 601                 if (arr == NULL) {
 602                         DPRINTF(("save_a: malloc failed"));
 603                         return (-1);
 604                 }
 605                 INIT_LINK(arr, link);
 606                 memset(&arr->addr, 0, sizeof(arr->addr));
 607                 switch (ns_rr_type(rr)) {
 608                 case ns_t_a:
 609                         arr->addr.sin.sin_family = AF_INET;
 610 #ifdef HAVE_SA_LEN
 611                         arr->addr.sin.sin_len = sizeof(arr->addr.sin);
 612 #endif
 613                         memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr),
 614                                NS_INADDRSZ);
 615                         arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
 616                         nsrr->flags |= RR_NS_HAVE_V4;
 617                         break;
 618                 case ns_t_aaaa:
 619                         arr->addr.sin6.sin6_family = AF_INET6;
 620 #ifdef HAVE_SA_LEN
 621                         arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6);
 622 #endif
 623                         memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16);
 624                         arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
 625                         nsrr->flags |= RR_NS_HAVE_V6;
 626                         break;
 627                 default:
 628                         abort();
 629                 }
 630                 APPEND(nsrr->addrs, arr, link);
 631         }
 632         return (0);
 633 }
 634
 635 static void
 636 free_nsrrset(rrset_ns *nsrrsp) {
 637         rr_ns *nsrr;
 638
 639         while ((nsrr = HEAD(*nsrrsp)) != NULL)
 640                 free_nsrr(nsrrsp, nsrr);
 641 }
 642
 643 static void
 644 free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) {
 645         rr_a *arr;
 646         char *tmp;
 647
 648         while ((arr = HEAD(nsrr->addrs)) != NULL) {
 649                 UNLINK(nsrr->addrs, arr, link);
 650                 free(arr);
 651         }
 652         DE_CONST(nsrr->name, tmp);
 653         free(tmp);
 654         UNLINK(*nsrrsp, nsrr, link);
 655         free(nsrr);
 656 }
 657
 658 static rr_ns *
 659 find_ns(rrset_ns *nsrrsp, const char *dname) {
 660         rr_ns *nsrr;
 661
 662         for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link))
 663                 if (ns_samename(nsrr->name, dname) == 1)
 664                         return (nsrr);
 665         return (NULL);
 666 }
 667
 668 static int
 669 do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
 670          u_char *resp, ns_msg *msg)
 671 {
 672         u_char req[NS_PACKETSZ];
 673         int i, n;
 674
 675         n = res_nmkquery(statp, ns_o_query, dname, class, qtype,
 676                          NULL, 0, NULL, req, NS_PACKETSZ);
 677         if (n < 0) {
 678                 DPRINTF(("do_query: res_nmkquery failed"));
 679                 return (-1);
 680         }
 681         n = res_nsend(statp, req, n, resp, NS_MAXMSG);
 682         if (n < 0) {
 683                 DPRINTF(("do_query: res_nsend failed"));
 684                 return (-1);
 685         }
 686         if (n == 0) {
 687                 DPRINTF(("do_query: res_nsend returned 0"));
 688                 errno = EMSGSIZE;
 689                 return (-1);
 690         }
 691         if (ns_initparse(resp, n, msg) < 0) {
 692                 DPRINTF(("do_query: ns_initparse failed"));
 693                 return (-1);
 694         }
 695         n = 0;
 696         for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
 697                 ns_rr rr;
 698
 699                 if (ns_parserr(msg, ns_s_an, i, &rr) < 0) {
 700                         DPRINTF(("do_query: ns_parserr failed"));
 701                         return (-1);
 702                 }
 703                 n += (ns_rr_class(rr) == class &&
 704                       (ns_rr_type(rr) == ns_t_cname ||
 705                        ns_rr_type(rr) == ns_t_dname));
 706         }
 707         return (n);
 708 }
 709
 710 static void
 711 res_dprintf(const char *fmt, ...) {
 712         va_list ap;
 713
 714         va_start(ap, fmt);
 715         fputs(";; res_findzonecut: ", stderr);
 716         vfprintf(stderr, fmt, ap);
 717         fputc('\n', stderr);
 718         va_end(ap);
 719 }