lib/libc/net/gethostbydns.c

   1 /*
   2  * ++Copyright++ 1985, 1988, 1993
   3  * -
   4  * Copyright (c) 1985, 1988, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 4. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  * -
  31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  32  *
  33  * Permission to use, copy, modify, and distribute this software for any
  34  * purpose with or without fee is hereby granted, provided that the above
  35  * copyright notice and this permission notice appear in all copies, and that
  36  * the name of Digital Equipment Corporation not be used in advertising or
  37  * publicity pertaining to distribution of the document or software without
  38  * specific, written prior permission.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  47  * SOFTWARE.
  48  * -
  49  * --Copyright--
  50  *
  51  * @(#)gethostnamadr.c  8.1 (Berkeley) 6/4/93
  52  * From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $
  53  * $FreeBSD: src/lib/libc/net/gethostbydns.c,v 1.58 2007/01/09 00:28:02 imp Exp $
  54  * $DragonFly: src/lib/libc/net/gethostbydns.c,v 1.6 2005/11/13 02:04:47 swildner Exp $
  55  */
  56
  57 #include <sys/types.h>
  58 #include <sys/param.h>
  59 #include <sys/socket.h>
  60 #include <netinet/in.h>
  61 #include <arpa/inet.h>
  62 #include <arpa/nameser.h>
  63
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <unistd.h>
  67 #include <string.h>
  68 #include <netdb.h>
  69 #include <resolv.h>
  70 #include <ctype.h>
  71 #include <errno.h>
  72 #include <syslog.h>
  73 #include <stdarg.h>
  74 #include <nsswitch.h>
  75
  76 #include "netdb_private.h"
  77 #include "res_config.h"
  78
  79 #define SPRINTF(x) ((size_t)sprintf x)
  80
  81 static const char AskedForGot[] =
  82                 "gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
  83
  84 #ifdef RESOLVSORT
  85 static void addrsort(char **, int, res_state);
  86 #endif
  87
  88 #ifdef DEBUG
  89 static void dprintf(char *, int, res_state) __printflike(1, 0);
  90 #endif
  91
  92 #define MAXPACKET       (64*1024)
  93
  94 typedef union {
  95     HEADER hdr;
  96     u_char buf[MAXPACKET];
  97 } querybuf;
  98
  99 typedef union {
 100     int32_t al;
 101     char ac;
 102 } align;
 103
 104 int _dns_ttl_;
 105
 106 #ifdef DEBUG
 107 static void
 108 dprintf(char *msg, int num, res_state res)
 109 {
 110         if (res->options & RES_DEBUG) {
 111                 int save = errno;
 112
 113                 printf(msg, num);
 114                 errno = save;
 115         }
 116 }
 117 #else
 118 # define dprintf(msg, num, res) /*nada*/
 119 #endif
 120
 121 #define BOUNDED_INCR(x) \
 122         do { \
 123                 cp += x; \
 124                 if (cp > eom) { \
 125                         RES_SET_H_ERRNO(statp, NO_RECOVERY); \
 126                         return (-1); \
 127                 } \
 128         } while (0)
 129
 130 #define BOUNDS_CHECK(ptr, count) \
 131         do { \
 132                 if ((ptr) + (count) > eom) { \
 133                         RES_SET_H_ERRNO(statp, NO_RECOVERY); \
 134                         return (-1); \
 135                 } \
 136         } while (0)
 137
 138 static int
 139 gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
 140               struct hostent *he, struct hostent_data *hed, res_state statp)
 141 {
 142         const HEADER *hp;
 143         const u_char *cp;
 144         int n;
 145         const u_char *eom, *erdata;
 146         char *bp, *ep, **ap, **hap;
 147         int type, class, ancount, qdcount;
 148         int haveanswer, had_error;
 149         int toobig = 0;
 150         char tbuf[MAXDNAME];
 151         const char *tname;
 152         int (*name_ok)(const char *);
 153
 154         tname = qname;
 155         he->h_name = NULL;
 156         eom = answer->buf + anslen;
 157         switch (qtype) {
 158         case T_A:
 159         case T_AAAA:
 160                 name_ok = res_hnok;
 161                 break;
 162         case T_PTR:
 163                 name_ok = res_dnok;
 164                 break;
 165         default:
 166                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 167                 return (-1);    /* XXX should be abort(); */
 168         }
 169         /*
 170          * find first satisfactory answer
 171          */
 172         hp = &answer->hdr;
 173         ancount = ntohs(hp->ancount);
 174         qdcount = ntohs(hp->qdcount);
 175         bp = hed->hostbuf;
 176         ep = hed->hostbuf + sizeof hed->hostbuf;
 177         cp = answer->buf;
 178         BOUNDED_INCR(HFIXEDSZ);
 179         if (qdcount != 1) {
 180                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 181                 return (-1);
 182         }
 183         n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 184         if ((n < 0) || !(*name_ok)(bp)) {
 185                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 186                 return (-1);
 187         }
 188         BOUNDED_INCR(n + QFIXEDSZ);
 189         if (qtype == T_A || qtype == T_AAAA) {
 190                 /* res_send() has already verified that the query name is the
 191                  * same as the one we sent; this just gets the expanded name
 192                  * (i.e., with the succeeding search-domain tacked on).
 193                  */
 194                 n = strlen(bp) + 1;             /* for the \0 */
 195                 if (n >= MAXHOSTNAMELEN) {
 196                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 197                         return (-1);
 198                 }
 199                 he->h_name = bp;
 200                 bp += n;
 201                 /* The qname can be abbreviated, but h_name is now absolute. */
 202                 qname = he->h_name;
 203         }
 204         ap = hed->host_aliases;
 205         *ap = NULL;
 206         he->h_aliases = hed->host_aliases;
 207         hap = hed->h_addr_ptrs;
 208         *hap = NULL;
 209         he->h_addr_list = hed->h_addr_ptrs;
 210         haveanswer = 0;
 211         had_error = 0;
 212         _dns_ttl_ = -1;
 213         while (ancount-- > 0 && cp < eom && !had_error) {
 214                 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 215                 if ((n < 0) || !(*name_ok)(bp)) {
 216                         had_error++;
 217                         continue;
 218                 }
 219                 cp += n;                        /* name */
 220                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 221                 type = _getshort(cp);
 222                 cp += INT16SZ;                  /* type */
 223                 class = _getshort(cp);
 224                 cp += INT16SZ;                  /* class */
 225                 if (qtype == T_A  && type == T_A)
 226                         _dns_ttl_ = _getlong(cp);
 227                 cp += INT32SZ;                  /* TTL */
 228                 n = _getshort(cp);
 229                 cp += INT16SZ;                  /* len */
 230                 BOUNDS_CHECK(cp, n);
 231                 erdata = cp + n;
 232                 if (class != C_IN) {
 233                         /* XXX - debug? syslog? */
 234                         cp += n;
 235                         continue;               /* XXX - had_error++ ? */
 236                 }
 237                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 238                         if (ap >= &hed->host_aliases[_MAXALIASES-1])
 239                                 continue;
 240                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 241                         if ((n < 0) || !(*name_ok)(tbuf)) {
 242                                 had_error++;
 243                                 continue;
 244                         }
 245                         cp += n;
 246                         if (cp != erdata) {
 247                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 248                                 return (-1);
 249                         }
 250                         /* Store alias. */
 251                         *ap++ = bp;
 252                         n = strlen(bp) + 1;     /* for the \0 */
 253                         if (n >= MAXHOSTNAMELEN) {
 254                                 had_error++;
 255                                 continue;
 256                         }
 257                         bp += n;
 258                         /* Get canonical name. */
 259                         n = strlen(tbuf) + 1;   /* for the \0 */
 260                         if (n > ep - bp || n >= MAXHOSTNAMELEN) {
 261                                 had_error++;
 262                                 continue;
 263                         }
 264                         strcpy(bp, tbuf);
 265                         he->h_name = bp;
 266                         bp += n;
 267                         continue;
 268                 }
 269                 if (qtype == T_PTR && type == T_CNAME) {
 270                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 271                         if (n < 0 || !res_dnok(tbuf)) {
 272                                 had_error++;
 273                                 continue;
 274                         }
 275                         cp += n;
 276                         if (cp != erdata) {
 277                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 278                                 return (-1);
 279                         }
 280                         /* Get canonical name. */
 281                         n = strlen(tbuf) + 1;   /* for the \0 */
 282                         if (n > ep - bp || n >= MAXHOSTNAMELEN) {
 283                                 had_error++;
 284                                 continue;
 285                         }
 286                         strcpy(bp, tbuf);
 287                         tname = bp;
 288                         bp += n;
 289                         continue;
 290                 }
 291                 if (type != qtype) {
 292                         if (type != T_SIG)
 293                                 syslog(LOG_NOTICE|LOG_AUTH,
 294         "gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
 295                                        qname, p_class(C_IN), p_type(qtype),
 296                                        p_type(type));
 297                         cp += n;
 298                         continue;               /* XXX - had_error++ ? */
 299                 }
 300                 switch (type) {
 301                 case T_PTR:
 302                         if (strcasecmp(tname, bp) != 0) {
 303                                 syslog(LOG_NOTICE|LOG_AUTH,
 304                                        AskedForGot, qname, bp);
 305                                 cp += n;
 306                                 continue;       /* XXX - had_error++ ? */
 307                         }
 308                         n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 309                         if ((n < 0) || !res_hnok(bp)) {
 310                                 had_error++;
 311                                 break;
 312                         }
 313 #if MULTI_PTRS_ARE_ALIASES
 314                         cp += n;
 315                         if (cp != erdata) {
 316                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 317                                 return (-1);
 318                         }
 319                         if (!haveanswer)
 320                                 he->h_name = bp;
 321                         else if (ap < &hed->host_aliases[_MAXALIASES-1])
 322                                 *ap++ = bp;
 323                         else
 324                                 n = -1;
 325                         if (n != -1) {
 326                                 n = strlen(bp) + 1;     /* for the \0 */
 327                                 if (n >= MAXHOSTNAMELEN) {
 328                                         had_error++;
 329                                         break;
 330                                 }
 331                                 bp += n;
 332                         }
 333                         break;
 334 #else
 335                         he->h_name = bp;
 336                         if (statp->options & RES_USE_INET6) {
 337                                 n = strlen(bp) + 1;     /* for the \0 */
 338                                 if (n >= MAXHOSTNAMELEN) {
 339                                         had_error++;
 340                                         break;
 341                                 }
 342                                 bp += n;
 343                                 _map_v4v6_hostent(he, &bp, ep);
 344                         }
 345                         RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 346                         return (0);
 347 #endif
 348                 case T_A:
 349                 case T_AAAA:
 350                         if (strcasecmp(he->h_name, bp) != 0) {
 351                                 syslog(LOG_NOTICE|LOG_AUTH,
 352                                        AskedForGot, he->h_name, bp);
 353                                 cp += n;
 354                                 continue;       /* XXX - had_error++ ? */
 355                         }
 356                         if (n != he->h_length) {
 357                                 cp += n;
 358                                 continue;
 359                         }
 360                         if (!haveanswer) {
 361                                 int nn;
 362
 363                                 he->h_name = bp;
 364                                 nn = strlen(bp) + 1;    /* for the \0 */
 365                                 bp += nn;
 366                         }
 367
 368                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 369
 370                         if (bp + n >= ep) {
 371                                 dprintf("size (%d) too big\n", n, statp);
 372                                 had_error++;
 373                                 continue;
 374                         }
 375                         if (hap >= &hed->h_addr_ptrs[_MAXADDRS-1]) {
 376                                 if (!toobig++)
 377                                         dprintf("Too many addresses (%d)\n",
 378                                                 _MAXADDRS, statp);
 379                                 cp += n;
 380                                 continue;
 381                         }
 382                         memcpy(*hap++ = bp, cp, n);
 383                         bp += n;
 384                         cp += n;
 385                         if (cp != erdata) {
 386                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 387                                 return (-1);
 388                         }
 389                         break;
 390                 default:
 391                         dprintf("Impossible condition (type=%d)\n", type,
 392                             statp);
 393                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 394                         return (-1);
 395                         /* BIND has abort() here, too risky on bad data */
 396                 }
 397                 if (!had_error)
 398                         haveanswer++;
 399         }
 400         if (haveanswer) {
 401                 *ap = NULL;
 402                 *hap = NULL;
 403 # if defined(RESOLVSORT)
 404                 /*
 405                  * Note: we sort even if host can take only one address
 406                  * in its return structures - should give it the "best"
 407                  * address in that case, not some random one
 408                  */
 409                 if (statp->nsort && haveanswer > 1 && qtype == T_A)
 410                         addrsort(hed->h_addr_ptrs, haveanswer, statp);
 411 # endif /*RESOLVSORT*/
 412                 if (!he->h_name) {
 413                         n = strlen(qname) + 1;  /* for the \0 */
 414                         if (n > ep - bp || n >= MAXHOSTNAMELEN)
 415                                 goto no_recovery;
 416                         strcpy(bp, qname);
 417                         he->h_name = bp;
 418                         bp += n;
 419                 }
 420                 if (statp->options & RES_USE_INET6)
 421                         _map_v4v6_hostent(he, &bp, ep);
 422                 RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 423                 return (0);
 424         }
 425  no_recovery:
 426         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 427         return (-1);
 428 }
 429
 430 /* XXX: for async DNS resolver in ypserv */
 431 struct hostent *
 432 __dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
 433 {
 434         struct hostent *he;
 435         struct hostent_data *hed;
 436         int error;
 437         res_state statp;
 438
 439         statp = __res_state();
 440         if ((he = __hostent_init()) == NULL ||
 441             (hed = __hostent_data_init()) == NULL) {
 442                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 443                 return (NULL);
 444         }
 445         switch (qtype) {
 446         case T_AAAA:
 447                 he->h_addrtype = AF_INET6;
 448                 he->h_length = NS_IN6ADDRSZ;
 449                 break;
 450         case T_A:
 451         default:
 452                 he->h_addrtype = AF_INET;
 453                 he->h_length = NS_INADDRSZ;
 454                 break;
 455         }
 456
 457         error = gethostanswer((const querybuf *)answer, anslen, qname, qtype,
 458             he, hed, statp);
 459         return (error == 0) ? he : NULL;
 460 }
 461
 462 int
 463 _dns_gethostbyname(void *rval, void *cb_data, va_list ap)
 464 {
 465         const char *name;
 466         int af;
 467         char *buffer;
 468         size_t buflen;
 469         int *errnop, *h_errnop;
 470         struct hostent *hptr, he;
 471         struct hostent_data *hed;
 472         querybuf *buf;
 473         int n, type, error;
 474         res_state statp;
 475
 476         name = va_arg(ap, const char *);
 477         af = va_arg(ap, int);
 478         hptr = va_arg(ap, struct hostent *);
 479         buffer = va_arg(ap, char *);
 480         buflen = va_arg(ap, size_t);
 481         errnop = va_arg(ap, int *);
 482         h_errnop = va_arg(ap, int *);
 483
 484         *((struct hostent **)rval) = NULL;
 485
 486         statp = __res_state();
 487         if ((hed = __hostent_data_init()) == NULL) {
 488                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 489                 *h_errnop = statp->res_h_errno;
 490                 return (NS_NOTFOUND);
 491         }
 492
 493         he.h_addrtype = af;
 494         switch (af) {
 495         case AF_INET:
 496                 he.h_length = NS_INADDRSZ;
 497                 type = T_A;
 498                 break;
 499         case AF_INET6:
 500                 he.h_length = NS_IN6ADDRSZ;
 501                 type = T_AAAA;
 502                 break;
 503         default:
 504                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 505                 *h_errnop = statp->res_h_errno;
 506                 errno = EAFNOSUPPORT;
 507                 return (NS_UNAVAIL);
 508         }
 509
 510         if ((buf = malloc(sizeof(*buf))) == NULL) {
 511                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 512                 *h_errnop = statp->res_h_errno;
 513                 return (NS_NOTFOUND);
 514         }
 515         n = res_nsearch(statp, name, C_IN, type, buf->buf, sizeof(buf->buf));
 516         if (n < 0) {
 517                 free(buf);
 518                 dprintf("res_nsearch failed (%d)\n", n, statp);
 519                 *h_errnop = statp->res_h_errno;
 520                 return (0);
 521         } else if (n > sizeof(buf->buf)) {
 522                 free(buf);
 523                 dprintf("static buffer is too small (%d)\n", n, statp);
 524                 *h_errnop = statp->res_h_errno;
 525                 return (0);
 526         }
 527         error = gethostanswer(buf, n, name, type, &he, hed, statp);
 528         free(buf);
 529         if (error != 0) {
 530                 *h_errnop = statp->res_h_errno;
 531                 return (NS_NOTFOUND);
 532         }
 533         if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
 534                 *h_errnop = statp->res_h_errno;
 535                 return (NS_NOTFOUND);
 536         }
 537         *((struct hostent **)rval) = hptr;
 538         return (NS_SUCCESS);
 539 }
 540
 541 int
 542 _dns_gethostbyaddr(void *rval, void *cb_data, va_list ap)
 543 {
 544         const void *addr;
 545         socklen_t len;
 546         int af;
 547         char *buffer;
 548         size_t buflen;
 549         int *errnop, *h_errnop;
 550         const u_char *uaddr;
 551         struct hostent *hptr, he;
 552         struct hostent_data *hed;
 553         int n;
 554         querybuf *buf;
 555         char qbuf[MAXDNAME+1], *qp;
 556         res_state statp;
 557 #ifdef SUNSECURITY
 558         struct hostdata rhd;
 559         struct hostent *rhe;
 560         char **haddr;
 561         u_long old_options;
 562         char hname2[MAXDNAME+1], numaddr[46];
 563         int ret_h_error;
 564 #endif /*SUNSECURITY*/
 565
 566         addr = va_arg(ap, const void *);
 567         len = va_arg(ap, socklen_t);
 568         af = va_arg(ap, int);
 569         hptr = va_arg(ap, struct hostent *);
 570         buffer = va_arg(ap, char *);
 571         buflen = va_arg(ap, size_t);
 572         errnop = va_arg(ap, int *);
 573         h_errnop = va_arg(ap, int *);
 574         uaddr = (const u_char *)addr;
 575
 576         *((struct hostent **)rval) = NULL;
 577
 578         statp = __res_state();
 579         if ((hed = __hostent_data_init()) == NULL) {
 580                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 581                 *h_errnop = statp->res_h_errno;
 582                 return (NS_NOTFOUND);
 583         }
 584
 585         switch (af) {
 586         case AF_INET:
 587                 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 588                                (uaddr[3] & 0xff),
 589                                (uaddr[2] & 0xff),
 590                                (uaddr[1] & 0xff),
 591                                (uaddr[0] & 0xff));
 592                 break;
 593         case AF_INET6:
 594                 qp = qbuf;
 595                 for (n = NS_IN6ADDRSZ - 1; n >= 0; n--) {
 596                         qp += SPRINTF((qp, "%x.%x.",
 597                                        uaddr[n] & 0xf,
 598                                        (uaddr[n] >> 4) & 0xf));
 599                 }
 600                 strlcat(qbuf, "ip6.arpa", sizeof(qbuf));
 601                 break;
 602         default:
 603                 abort();
 604         }
 605         if ((buf = malloc(sizeof(*buf))) == NULL) {
 606                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 607                 *h_errnop = statp->res_h_errno;
 608                 return NS_NOTFOUND;
 609         }
 610         n = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf->buf,
 611             sizeof buf->buf);
 612         if (n < 0) {
 613                 free(buf);
 614                 dprintf("res_nquery failed (%d)\n", n, statp);
 615                 *h_errnop = statp->res_h_errno;
 616                 return (NS_UNAVAIL);
 617         }
 618         if (n > sizeof buf->buf) {
 619                 free(buf);
 620                 dprintf("static buffer is too small (%d)\n", n, statp);
 621                 *h_errnop = statp->res_h_errno;
 622                 return (NS_UNAVAIL);
 623         }
 624         if (gethostanswer(buf, n, qbuf, T_PTR, &he, hed, statp) != 0) {
 625                 free(buf);
 626                 *h_errnop = statp->res_h_errno;
 627                 return (NS_NOTFOUND);   /* h_errno was set by gethostanswer() */
 628         }
 629         free(buf);
 630 #ifdef SUNSECURITY
 631         if (af == AF_INET) {
 632             /*
 633              * turn off search as the name should be absolute,
 634              * 'localhost' should be matched by defnames
 635              */
 636             strncpy(hname2, he.h_name, MAXDNAME);
 637             hname2[MAXDNAME] = '\0';
 638             old_options = statp->options;
 639             statp->options &= ~RES_DNSRCH;
 640             statp->options |= RES_DEFNAMES;
 641             memset(&rhd, 0, sizeof rhd);
 642             rhe = gethostbyname_r(hname2, &rhd.host, &rhd.data,
 643                 sizeof(rhd.data), &ret_h_error);
 644             if (rhe == NULL) {
 645                 if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
 646                     strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
 647                 syslog(LOG_NOTICE|LOG_AUTH,
 648                        "gethostbyaddr: No A record for %s (verifying [%s])",
 649                        hname2, numaddr);
 650                 statp->options = old_options;
 651                 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 652                 *h_errnop = statp->res_h_errno;
 653                 return (NS_NOTFOUND);
 654             }
 655             statp->options = old_options;
 656             for (haddr = rhe->h_addr_list; *haddr; haddr++)
 657                 if (!memcmp(*haddr, addr, NS_INADDRSZ))
 658                         break;
 659             if (!*haddr) {
 660                 if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
 661                     strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
 662                 syslog(LOG_NOTICE|LOG_AUTH,
 663                        "gethostbyaddr: A record of %s != PTR record [%s]",
 664                        hname2, numaddr);
 665                 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 666                 *h_errnop = statp->res_h_errno;
 667                 return (NS_NOTFOUND);
 668             }
 669         }
 670 #endif /*SUNSECURITY*/
 671         he.h_addrtype = af;
 672         he.h_length = len;
 673         memcpy(hed->host_addr, uaddr, len);
 674         hed->h_addr_ptrs[0] = (char *)hed->host_addr;
 675         hed->h_addr_ptrs[1] = NULL;
 676         if (af == AF_INET && (statp->options & RES_USE_INET6)) {
 677                 _map_v4v6_address((char*)hed->host_addr, (char*)hed->host_addr);
 678                 he.h_addrtype = AF_INET6;
 679                 he.h_length = NS_IN6ADDRSZ;
 680         }
 681         RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 682         if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
 683                 *h_errnop = statp->res_h_errno;
 684                 return (NS_NOTFOUND);
 685         }
 686         *((struct hostent **)rval) = hptr;
 687         return (NS_SUCCESS);
 688 }
 689
 690 #ifdef RESOLVSORT
 691 static void
 692 addrsort(char **ap, int num, res_state res)
 693 {
 694         int i, j;
 695         char **p;
 696         short aval[_MAXADDRS];
 697         int needsort = 0;
 698
 699         p = ap;
 700         for (i = 0; i < num; i++, p++) {
 701             for (j = 0 ; (unsigned)j < res->nsort; j++)
 702                 if (res->sort_list[j].addr.s_addr ==
 703                     (((struct in_addr *)(*p))->s_addr & res->sort_list[j].mask))
 704                         break;
 705             aval[i] = j;
 706             if (needsort == 0 && i > 0 && j < aval[i-1])
 707                 needsort = i;
 708         }
 709         if (!needsort)
 710             return;
 711
 712         while (needsort < num) {
 713             for (j = needsort - 1; j >= 0; j--) {
 714                 if (aval[j] > aval[j+1]) {
 715                     char *hp;
 716
 717                     i = aval[j];
 718                     aval[j] = aval[j+1];
 719                     aval[j+1] = i;
 720
 721                     hp = ap[j];
 722                     ap[j] = ap[j+1];
 723                     ap[j+1] = hp;
 724
 725                 } else
 726                     break;
 727             }
 728             needsort++;
 729         }
 730 }
 731 #endif
 732
 733 void
 734 _sethostdnsent(int stayopen)
 735 {
 736         res_state statp;
 737
 738         statp = __res_state();
 739         if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
 740                 return;
 741         if (stayopen)
 742                 statp->options |= RES_STAYOPEN | RES_USEVC;
 743 }
 744
 745 void
 746 _endhostdnsent(void)
 747 {
 748         res_state statp;
 749
 750         statp = __res_state();
 751         statp->options &= ~(RES_STAYOPEN | RES_USEVC);
 752         res_nclose(statp);
 753 }