res_findzonecut.c

   1 #ifndef __APPLE__
   2 #if !defined(lint) && !defined(SABER)
   3 static const char rcsid[] = "$Id: res_findzonecut.c,v 1.1 2006/03/01 19:01:38 majka Exp $";
   4 #endif /* not lint */
   5 #endif
   6
   7 /*
   8  * Copyright (c) 1999 by Internet Software Consortium.
   9  *
  10  * Permission to use, copy, modify, and distribute this software for any
  11  * purpose with or without fee is hereby granted, provided that the above
  12  * copyright notice and this permission notice appear in all copies.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  15  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  17  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  18  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  19  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  20  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  21  * SOFTWARE.
  22  */
  23
  24 /* Import. */
  25
  26 #ifndef __APPLE__
  27 #include "port_before.h"
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/socket.h>
  32 #include <sys/time.h>
  33
  34 #include <netinet/in.h>
  35 #include <arpa/inet.h>
  36 #include <arpa/nameser.h>
  37
  38 #include <errno.h>
  39 #include <limits.h>
  40 #include <netdb.h>
  41 #include <stdarg.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46 #ifndef __APPLE__
  47 #include <isc/list.h>
  48 #include "port_after.h"
  49 #else
  50 #include <res_update.h>
  51 #endif
  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         int                     have_v4;
  67         int                     have_v6;
  68         rrset_a                 addrs;
  69 } rr_ns;
  70 typedef LIST(rr_ns) rrset_ns;
  71
  72 /* Forward. */
  73
  74 static int      satisfy(res_state, const char *, rrset_ns *,
  75                         union res_sockaddr_union *, int);
  76 static int      add_addrs(res_state, rr_ns *,
  77                           union res_sockaddr_union *, int);
  78 static int      get_soa(res_state, const char *, ns_class, int,
  79                         char *, size_t, char *, size_t,
  80                         rrset_ns *);
  81 static int      get_ns(res_state, const char *, ns_class, int, rrset_ns *);
  82 static int      get_glue(res_state, ns_class, int, rrset_ns *);
  83 static int      save_ns(res_state, ns_msg *, ns_sect,
  84                         const char *, ns_class, int, rrset_ns *);
  85 static int      save_a(res_state, ns_msg *, ns_sect,
  86                        const char *, ns_class, int, rr_ns *);
  87 static void     free_nsrrset(rrset_ns *);
  88 static void     free_nsrr(rrset_ns *, rr_ns *);
  89 static rr_ns *  find_ns(rrset_ns *, const char *);
  90 static int      do_query(res_state, const char *, ns_class, ns_type,
  91                          u_char *, ns_msg *);
  92 #ifndef __APPLE__
  93 static void     res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2);
  94 #else
  95 static void     res_dprintf(const char *, ...);
  96 #endif
  97
  98 /* Macros. */
  99
 100 #define DPRINTF(x) do {\
 101                 int save_errno = errno; \
 102                 if ((statp->options & RES_DEBUG) != 0) res_dprintf x; \
 103                 errno = save_errno; \
 104         } while (0)
 105
 106 /* Public. */
 107
 108 /*
 109  * int
 110  * res_findzonecut(res, dname, class, zname, zsize, addrs, naddrs)
 111  *      find enclosing zone for a <dname,class>, and some server addresses
 112  * parameters:
 113  *      res - resolver context to work within (is modified)
 114  *      dname - domain name whose enclosing zone is desired
 115  *      class - class of dname (and its enclosing zone)
 116  *      zname - found zone name
 117  *      zsize - allocated size of zname
 118  *      addrs - found server addresses
 119  *      naddrs - max number of addrs
 120  * return values:
 121  *      < 0 - an error occurred (check errno)
 122  *      = 0 - zname is now valid, but addrs[] wasn't changed
 123  *      > 0 - zname is now valid, and return value is number of addrs[] found
 124  * notes:
 125  *      this function calls res_nsend() which means it depends on correctly
 126  *      functioning recursive nameservers (usually defined in /etc/resolv.conf
 127  *      or its local equivilent).
 128  *
 129  *      we start by asking for an SOA<dname,class>.  if we get one as an
 130  *      answer, that just means <dname,class> is a zone top, which is fine.
 131  *      more than likely we'll be told to go pound sand, in the form of a
 132  *      negative answer.
 133  *
 134  *      note that we are not prepared to deal with referrals since that would
 135  *      only come from authority servers and our correctly functioning local
 136  *      recursive server would have followed the referral and got us something
 137  *      more definite.
 138  *
 139  *      if the authority section contains an SOA, this SOA should also be the
 140  *      closest enclosing zone, since any intermediary zone cuts would've been
 141  *      returned as referrals and dealt with by our correctly functioning local
 142  *      recursive name server.  but an SOA in the authority section should NOT
 143  *      match our dname (since that would have been returned in the answer
 144  *      section).  an authority section SOA has to be "above" our dname.
 145  *
 146  *      however, since authority section SOA's were once optional, it's
 147  *      possible that we'll have to go hunting for the enclosing SOA by
 148  *      ripping labels off the front of our dname -- this is known as "doing
 149  *      it the hard way."
 150  *
 151  *      ultimately we want some server addresses, which are ideally the ones
 152  *      pertaining to the SOA.MNAME, but only if there is a matching NS RR.
 153  *      so the second phase (after we find an SOA) is to go looking for the
 154  *      NS RRset for that SOA's zone.
 155  *
 156  *      no answer section processed by this code is allowed to contain CNAME
 157  *      or DNAME RR's.  for the SOA query this means we strip a label and
 158  *      keep going.  for the NS and A queries this means we just give up.
 159  */
 160
 161 int
 162 res_findzonecut(res_state statp, const char *dname, ns_class class, int opts,
 163                 char *zname, size_t zsize, struct in_addr *addrs, int naddrs) {
 164         int result, i;
 165         union res_sockaddr_union *u;
 166
 167
 168         opts |= RES_IPV4ONLY;
 169         opts &= ~RES_IPV6ONLY;
 170
 171         u = calloc(naddrs, sizeof(*u));
 172         if (u == NULL)
 173                 return(-1);
 174
 175         result = res_findzonecut2(statp, dname, class, opts, zname, zsize,
 176                                   u, naddrs);
 177
 178         for (i = 0; i < result; i++) {
 179                 addrs[i] = u[i].sin.sin_addr;
 180         }
 181         free(u);
 182         return (result);
 183 }
 184
 185 int
 186 res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts,
 187                  char *zname, size_t zsize, union res_sockaddr_union *addrs,
 188                  int naddrs)
 189 {
 190         char mname[NS_MAXDNAME];
 191         u_long save_pfcode;
 192         rrset_ns nsrrs;
 193         int n;
 194
 195         DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d",
 196                  dname, p_class(class), (long)zsize, naddrs));
 197         save_pfcode = statp->pfcode;
 198         statp->pfcode |= RES_PRF_HEAD2 | RES_PRF_HEAD1 | RES_PRF_HEADX |
 199                          RES_PRF_QUES | RES_PRF_ANS |
 200                          RES_PRF_AUTH | RES_PRF_ADD;
 201         INIT_LIST(nsrrs);
 202
 203         DPRINTF(("get the soa, and see if it has enough glue"));
 204         if ((n = get_soa(statp, dname, class, opts, zname, zsize,
 205                          mname, sizeof mname, &nsrrs)) < 0 ||
 206             ((opts & RES_EXHAUSTIVE) == 0 &&
 207              (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
 208                 goto done;
 209
 210         DPRINTF(("get the ns rrset and see if it has enough glue"));
 211         if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 ||
 212             ((opts & RES_EXHAUSTIVE) == 0 &&
 213              (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
 214                 goto done;
 215
 216         DPRINTF(("get the missing glue and see if it's finally enough"));
 217         if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0)
 218                 n = satisfy(statp, mname, &nsrrs, addrs, naddrs);
 219
 220  done:
 221         DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK"));
 222         free_nsrrset(&nsrrs);
 223         statp->pfcode = save_pfcode;
 224         return (n);
 225 }
 226
 227 /* Private. */
 228
 229 static int
 230 satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp,
 231         union res_sockaddr_union *addrs, int naddrs)
 232 {
 233         rr_ns *nsrr;
 234         int n, x;
 235
 236         n = 0;
 237         nsrr = find_ns(nsrrsp, mname);
 238         if (nsrr != NULL) {
 239                 x = add_addrs(statp, nsrr, addrs, naddrs);
 240                 addrs += x;
 241                 naddrs -= x;
 242                 n += x;
 243         }
 244         for (nsrr = HEAD(*nsrrsp);
 245              nsrr != NULL && naddrs > 0;
 246              nsrr = NEXT(nsrr, link))
 247                 if (ns_samename(nsrr->name, mname) != 1) {
 248                         x = add_addrs(statp, nsrr, addrs, naddrs);
 249                         addrs += x;
 250                         naddrs -= x;
 251                         n += x;
 252                 }
 253         DPRINTF(("satisfy(%s): %d", mname, n));
 254         return (n);
 255 }
 256
 257 static int
 258 add_addrs(res_state statp, rr_ns *nsrr,
 259           union res_sockaddr_union *addrs, int naddrs)
 260 {
 261         rr_a *arr;
 262         int n = 0;
 263
 264         for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) {
 265                 if (naddrs <= 0)
 266                         return (0);
 267                 *addrs++ = arr->addr;
 268                 naddrs--;
 269                 n++;
 270         }
 271         DPRINTF(("add_addrs: %d", n));
 272         return (n);
 273 }
 274
 275 static int
 276 get_soa(res_state statp, const char *dname, ns_class class, int opts,
 277         char *zname, size_t zsize, char *mname, size_t msize,
 278         rrset_ns *nsrrsp)
 279 {
 280         char tname[NS_MAXDNAME];
 281         u_char resp[NS_PACKETSZ];
 282         int n, i, ancount, nscount;
 283         ns_sect sect;
 284         ns_msg msg;
 285         u_int rcode;
 286
 287         /*
 288          * Find closest enclosing SOA, even if it's for the root zone.
 289          */
 290
 291         /* First canonicalize dname (exactly one unescaped trailing "."). */
 292         if (ns_makecanon(dname, tname, sizeof tname) < 0)
 293                 return (-1);
 294         dname = tname;
 295
 296         /* Now grovel the subdomains, hunting for an SOA answer or auth. */
 297         for (;;) {
 298                 /* Leading or inter-label '.' are skipped here. */
 299                 while (*dname == '.')
 300                         dname++;
 301
 302                 /* Is there an SOA? */
 303                 n = do_query(statp, dname, class, ns_t_soa, resp, &msg);
 304                 if (n < 0) {
 305                         DPRINTF(("get_soa: do_query('%s', %s) failed (%d)",
 306                                  dname, p_class(class), n));
 307                         return (-1);
 308                 }
 309                 if (n > 0) {
 310                         DPRINTF(("get_soa: CNAME or DNAME found"));
 311                         sect = ns_s_max, n = 0;
 312                 } else {
 313                         rcode = ns_msg_getflag(msg, ns_f_rcode);
 314                         ancount = ns_msg_count(msg, ns_s_an);
 315                         nscount = ns_msg_count(msg, ns_s_ns);
 316                         if (ancount > 0 && rcode == ns_r_noerror)
 317                                 sect = ns_s_an, n = ancount;
 318                         else if (nscount > 0)
 319                                 sect = ns_s_ns, n = nscount;
 320                         else
 321                                 sect = ns_s_max, n = 0;
 322                 }
 323                 for (i = 0; i < n; i++) {
 324                         const char *t;
 325                         const u_char *rdata;
 326                         int rdlen;
 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                                 return (-1);
 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(("get_soa: ns_samedomain('%s', '%s') == 0",
 345                                                  dname, t));
 346                                         errno = EPROTOTYPE;
 347                                         return (-1);
 348                                 }
 349                                 break;
 350                         case ns_s_ns:
 351                                 if (ns_samename(dname, t) == 1 ||
 352                                     ns_samedomain(dname, t) == 0) {
 353                                         DPRINTF(("get_soa: ns_samename() || !ns_samedomain('%s', '%s')",
 354                                                  dname, t));
 355                                         errno = EPROTOTYPE;
 356                                         return (-1);
 357                                 }
 358                                 break;
 359                         default:
 360                                 abort();
 361                         }
 362                         if (strlen(t) + 1 > zsize) {
 363                                 DPRINTF(("get_soa: zname(%d) too small (%d)",
 364                                          zsize, strlen(t) + 1));
 365                                 errno = EMSGSIZE;
 366                                 return (-1);
 367                         }
 368                         strcpy(zname, t);
 369                         rdata = ns_rr_rdata(rr);
 370                         rdlen = ns_rr_rdlen(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                                 return (-1);
 375                         }
 376                         if (save_ns(statp, &msg, ns_s_ns,
 377                                     zname, class, opts, nsrrsp) < 0) {
 378                                 DPRINTF(("get_soa: save_ns failed"));
 379                                 return (-1);
 380                         }
 381                         return (0);
 382                 }
 383
 384                 /* If we're out of labels, then not even "." has an SOA! */
 385                 if (*dname == '\0')
 386                         break;
 387
 388                 /* Find label-terminating "."; top of loop will skip it. */
 389                 while (*dname != '.') {
 390                         if (*dname == '\\')
 391                                 if (*++dname == '\0') {
 392                                         errno = EMSGSIZE;
 393                                         return (-1);
 394                                 }
 395                         dname++;
 396                 }
 397         }
 398         DPRINTF(("get_soa: out of labels"));
 399         errno = EDESTADDRREQ;
 400         return (-1);
 401 }
 402
 403 static int
 404 get_ns(res_state statp, const char *zname, ns_class class, int opts,
 405       rrset_ns *nsrrsp)
 406 {
 407         u_char resp[NS_PACKETSZ];
 408         ns_msg msg;
 409         int n;
 410
 411         /* Go and get the NS RRs for this zone. */
 412         n = do_query(statp, zname, class, ns_t_ns, resp, &msg);
 413         if (n != 0) {
 414                 DPRINTF(("get_ns: do_query('%s', %s) failed (%d)",
 415                          zname, p_class(class), n));
 416                 return (-1);
 417         }
 418
 419         /* Remember the NS RRs and associated A RRs that came back. */
 420         if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) {
 421                 DPRINTF(("get_ns save_ns('%s', %s) failed",
 422                          zname, p_class(class)));
 423                 return (-1);
 424         }
 425
 426         return (0);
 427 }
 428
 429 static int
 430 get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) {
 431         rr_ns *nsrr, *nsrr_n;
 432
 433         /* Go and get the A RRs for each empty NS RR on our list. */
 434         for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) {
 435                 u_char resp[NS_PACKETSZ];
 436                 ns_msg msg;
 437                 int n;
 438
 439                 nsrr_n = NEXT(nsrr, link);
 440
 441                 if (!nsrr->have_v4) {
 442                         n = do_query(statp, nsrr->name, class, ns_t_a,
 443                                      resp, &msg);
 444                         if (n < 0) {
 445                                 DPRINTF(("get_glue: do_query('%s', %s') failed",
 446                                          nsrr->name, p_class(class)));
 447                                 return (-1);
 448                         }
 449                         if (n > 0) {
 450                                 DPRINTF((
 451                         "get_glue: do_query('%s', %s') CNAME or DNAME found",
 452                                          nsrr->name, p_class(class)));
 453                         }
 454                         if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
 455                                    opts, nsrr) < 0) {
 456                                 DPRINTF(("get_glue: save_r('%s', %s) failed",
 457                                          nsrr->name, p_class(class)));
 458                                 return (-1);
 459                         }
 460                 }
 461
 462                 if (!nsrr->have_v6) {
 463                         n = do_query(statp, nsrr->name, class, ns_t_aaaa,
 464                                      resp, &msg);
 465                         if (n < 0) {
 466                                 DPRINTF(("get_glue: do_query('%s', %s') failed",
 467                                          nsrr->name, p_class(class)));
 468                                 return (-1);
 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                                 return (-1);
 480                         }
 481                 }
 482
 483                 /* If it's still empty, it's just chaff. */
 484                 if (EMPTY(nsrr->addrs)) {
 485                         DPRINTF(("get_glue: removing empty '%s' NS",
 486                                  nsrr->name));
 487                         free_nsrr(nsrrsp, nsrr);
 488                 }
 489         }
 490         return (0);
 491 }
 492
 493 static int
 494 save_ns(res_state statp, ns_msg *msg, ns_sect sect,
 495         const char *owner, ns_class class, int opts,
 496         rrset_ns *nsrrsp)
 497 {
 498         int i;
 499
 500         for (i = 0; i < ns_msg_count(*msg, sect); i++) {
 501                 char tname[NS_MAXDNAME];
 502                 const u_char *rdata;
 503                 rr_ns *nsrr;
 504                 ns_rr rr;
 505                 int rdlen;
 506
 507                 if (ns_parserr(msg, sect, i, &rr) < 0) {
 508                         DPRINTF(("save_ns: ns_parserr(%s, %d) failed",
 509                                  p_section(sect, ns_o_query), i));
 510                         return (-1);
 511                 }
 512                 if (ns_rr_type(rr) != ns_t_ns ||
 513                     ns_rr_class(rr) != class ||
 514                     ns_samename(ns_rr_name(rr), owner) != 1)
 515                         continue;
 516                 nsrr = find_ns(nsrrsp, ns_rr_name(rr));
 517                 if (nsrr == NULL) {
 518                         nsrr = malloc(sizeof *nsrr);
 519                         if (nsrr == NULL) {
 520                                 DPRINTF(("save_ns: malloc failed"));
 521                                 return (-1);
 522                         }
 523                         rdata = ns_rr_rdata(rr);
 524                         rdlen = ns_rr_rdlen(rr);
 525                         if (ns_name_uncompress(ns_msg_base(*msg),
 526                                                ns_msg_end(*msg), rdata,
 527                                                tname, sizeof tname) < 0) {
 528                                 DPRINTF(("save_ns: ns_name_uncompress failed"));
 529                                 free(nsrr);
 530                                 return (-1);
 531                         }
 532                         nsrr->name = strdup(tname);
 533                         if (nsrr->name == NULL) {
 534                                 DPRINTF(("save_ns: strdup failed"));
 535                                 free(nsrr);
 536                                 return (-1);
 537                         }
 538                         INIT_LINK(nsrr, link);
 539                         INIT_LIST(nsrr->addrs);
 540                         nsrr->have_v4 = 0;
 541                         nsrr->have_v6 = 0;
 542                         APPEND(*nsrrsp, nsrr, link);
 543                 }
 544                 if (save_a(statp, msg, ns_s_ar,
 545                            nsrr->name, class, opts, nsrr) < 0) {
 546                         DPRINTF(("save_ns: save_r('%s', %s) failed",
 547                                  nsrr->name, p_class(class)));
 548                         return (-1);
 549                 }
 550         }
 551         return (0);
 552 }
 553
 554 static int
 555 save_a(res_state statp, ns_msg *msg, ns_sect sect,
 556        const char *owner, ns_class class, int opts,
 557        rr_ns *nsrr)
 558 {
 559         int i;
 560
 561         for (i = 0; i < ns_msg_count(*msg, sect); i++) {
 562                 ns_rr rr;
 563                 rr_a *arr;
 564
 565                 if (ns_parserr(msg, sect, i, &rr) < 0) {
 566                         DPRINTF(("save_a: ns_parserr(%s, %d) failed",
 567                                  p_section(sect, ns_o_query), i));
 568                         return (-1);
 569                 }
 570                 if ((ns_rr_type(rr) != ns_t_a && ns_rr_type(rr) != ns_t_aaaa) ||
 571                     ns_rr_class(rr) != class ||
 572                     ns_samename(ns_rr_name(rr), owner) != 1 ||
 573                     ns_rr_rdlen(rr) != NS_INADDRSZ)
 574                         continue;
 575                 if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa)
 576                         continue;
 577                 if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a)
 578                         continue;
 579                 arr = malloc(sizeof *arr);
 580                 if (arr == NULL) {
 581                         DPRINTF(("save_a: malloc failed"));
 582                         return (-1);
 583                 }
 584                 INIT_LINK(arr, link);
 585                 memset(&arr->addr, 0, sizeof(arr->addr));
 586                 switch (ns_rr_type(rr)) {
 587                 case ns_t_a:
 588                         arr->addr.sin.sin_family = AF_INET;
 589 #ifdef HAVE_SA_LEN
 590                         arr->addr.sin.sin_len = sizeof(arr->addr.sin);
 591 #endif
 592                         memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr),
 593                                NS_INADDRSZ);
 594                         arr->addr.sin.sin_port = htons(NS_DEFAULTPORT);
 595                         nsrr->have_v4 = 1;
 596                         break;
 597                 case ns_t_aaaa:
 598                         arr->addr.sin6.sin6_family = AF_INET6;
 599 #ifdef HAVE_SA_LEN
 600                         arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6);
 601 #endif
 602                         memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16);
 603                         arr->addr.sin.sin_port = htons(NS_DEFAULTPORT);
 604                         nsrr->have_v6 = 1;
 605                         break;
 606                 default:
 607                         abort();
 608                 }
 609                 APPEND(nsrr->addrs, arr, link);
 610         }
 611         return (0);
 612 }
 613
 614 static void
 615 free_nsrrset(rrset_ns *nsrrsp) {
 616         rr_ns *nsrr;
 617
 618         while ((nsrr = HEAD(*nsrrsp)) != NULL)
 619                 free_nsrr(nsrrsp, nsrr);
 620 }
 621
 622 static void
 623 free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) {
 624         rr_a *arr;
 625         char *tmp;
 626
 627         while ((arr = HEAD(nsrr->addrs)) != NULL) {
 628                 UNLINK(nsrr->addrs, arr, link);
 629                 free(arr);
 630         }
 631 #ifdef __APPLE__
 632         tmp = (char *)nsrr->name;
 633 #else
 634         DE_CONST(nsrr->name, tmp);
 635 #endif
 636         free(tmp);
 637         UNLINK(*nsrrsp, nsrr, link);
 638         free(nsrr);
 639 }
 640
 641 static rr_ns *
 642 find_ns(rrset_ns *nsrrsp, const char *dname) {
 643         rr_ns *nsrr;
 644
 645         for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link))
 646                 if (ns_samename(nsrr->name, dname) == 1)
 647                         return (nsrr);
 648         return (NULL);
 649 }
 650
 651 static int
 652 do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
 653          u_char *resp, ns_msg *msg)
 654 {
 655         u_char req[NS_PACKETSZ];
 656         int i, n;
 657
 658         n = res_nmkquery(statp, ns_o_query, dname, class, qtype,
 659                          NULL, 0, NULL, req, NS_PACKETSZ);
 660         if (n < 0) {
 661                 DPRINTF(("do_query: res_nmkquery failed"));
 662                 return (-1);
 663         }
 664         n = res_nsend(statp, req, n, resp, NS_PACKETSZ);
 665         if (n < 0) {
 666                 DPRINTF(("do_query: res_nsend failed"));
 667                 return (-1);
 668         }
 669         if (n == 0) {
 670                 DPRINTF(("do_query: res_nsend returned 0"));
 671                 errno = EMSGSIZE;
 672                 return (-1);
 673         }
 674         if (ns_initparse(resp, n, msg) < 0) {
 675                 DPRINTF(("do_query: ns_initparse failed"));
 676                 return (-1);
 677         }
 678         n = 0;
 679         for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
 680                 ns_rr rr;
 681
 682                 if (ns_parserr(msg, ns_s_an, i, &rr) < 0) {
 683                         DPRINTF(("do_query: ns_parserr failed"));
 684                         return (-1);
 685                 }
 686                 n += (ns_rr_class(rr) == class &&
 687                       (ns_rr_type(rr) == ns_t_cname ||
 688                        ns_rr_type(rr) == ns_t_dname));
 689         }
 690         return (n);
 691 }
 692
 693 static void
 694 res_dprintf(const char *fmt, ...) {
 695         va_list ap;
 696
 697         va_start(ap, fmt);
 698         fputs(";; res_findzonecut: ", stderr);
 699         vfprintf(stderr, fmt, ap);
 700         fputc('\n', stderr);
 701         va_end(ap);
 702 }