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
  52 #if defined(LIBC_SCCS) && !defined(lint)
  53 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
  54 static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $";
  55 #endif /* LIBC_SCCS and not lint */
  56 #include <sys/cdefs.h>
  57 __FBSDID("$FreeBSD$");
  58
  59 #include <sys/types.h>
  60 #include <sys/param.h>
  61 #include <sys/socket.h>
  62 #include <netinet/in.h>
  63 #include <arpa/inet.h>
  64 #include <arpa/nameser.h>
  65
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <unistd.h>
  69 #include <string.h>
  70 #include <netdb.h>
  71 #include <resolv.h>
  72 #include <ctype.h>
  73 #include <errno.h>
  74 #include <syslog.h>
  75 #include <stdarg.h>
  76 #include <nsswitch.h>
  77
  78 #include "netdb_private.h"
  79 #include "res_config.h"
  80
  81 #define SPRINTF(x) ((size_t)sprintf x)
  82
  83 static const char AskedForGot[] =
  84                 "gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
  85
  86 #ifdef RESOLVSORT
  87 static void addrsort(char **, int, res_state);
  88 #endif
  89
  90 #ifdef DEBUG
  91 static void dprintf(char *, int, res_state) __printflike(1, 0);
  92 #endif
  93
  94 #define MAXPACKET       (64*1024)
  95
  96 typedef union {
  97     HEADER hdr;
  98     u_char buf[MAXPACKET];
  99 } querybuf;
 100
 101 typedef union {
 102     int32_t al;
 103     char ac;
 104 } align;
 105
 106 int _dns_ttl_;
 107
 108 #ifdef DEBUG
 109 static void
 110 dprintf(msg, num, res)
 111         char *msg;
 112         int num;
 113         res_state res;
 114 {
 115         if (res->options & RES_DEBUG) {
 116                 int save = errno;
 117
 118                 printf(msg, num);
 119                 errno = save;
 120         }
 121 }
 122 #else
 123 # define dprintf(msg, num, res) /*nada*/
 124 #endif
 125
 126 #define BOUNDED_INCR(x) \
 127         do { \
 128                 cp += x; \
 129                 if (cp > eom) { \
 130                         RES_SET_H_ERRNO(statp, NO_RECOVERY); \
 131                         return (-1); \
 132                 } \
 133         } while (0)
 134
 135 #define BOUNDS_CHECK(ptr, count) \
 136         do { \
 137                 if ((ptr) + (count) > eom) { \
 138                         RES_SET_H_ERRNO(statp, NO_RECOVERY); \
 139                         return (-1); \
 140                 } \
 141         } while (0)
 142
 143 static int
 144 gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
 145     struct hostent *he, struct hostent_data *hed, res_state statp)
 146 {
 147         const HEADER *hp;
 148         const u_char *cp;
 149         int n;
 150         const u_char *eom, *erdata;
 151         char *bp, *ep, **ap, **hap;
 152         int type, class, ancount, qdcount;
 153         int haveanswer, had_error;
 154         int toobig = 0;
 155         char tbuf[MAXDNAME];
 156         const char *tname;
 157         int (*name_ok)(const char *);
 158
 159         tname = qname;
 160         he->h_name = NULL;
 161         eom = answer->buf + anslen;
 162         switch (qtype) {
 163         case T_A:
 164         case T_AAAA:
 165                 name_ok = res_hnok;
 166                 break;
 167         case T_PTR:
 168                 name_ok = res_dnok;
 169                 break;
 170         default:
 171                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 172                 return (-1);    /* XXX should be abort(); */
 173         }
 174         /*
 175          * find first satisfactory answer
 176          */
 177         hp = &answer->hdr;
 178         ancount = ntohs(hp->ancount);
 179         qdcount = ntohs(hp->qdcount);
 180         bp = hed->hostbuf;
 181         ep = hed->hostbuf + sizeof hed->hostbuf;
 182         cp = answer->buf;
 183         BOUNDED_INCR(HFIXEDSZ);
 184         if (qdcount != 1) {
 185                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 186                 return (-1);
 187         }
 188         n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 189         if ((n < 0) || !(*name_ok)(bp)) {
 190                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 191                 return (-1);
 192         }
 193         BOUNDED_INCR(n + QFIXEDSZ);
 194         if (qtype == T_A || qtype == T_AAAA) {
 195                 /* res_send() has already verified that the query name is the
 196                  * same as the one we sent; this just gets the expanded name
 197                  * (i.e., with the succeeding search-domain tacked on).
 198                  */
 199                 n = strlen(bp) + 1;             /* for the \0 */
 200                 if (n >= MAXHOSTNAMELEN) {
 201                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 202                         return (-1);
 203                 }
 204                 he->h_name = bp;
 205                 bp += n;
 206                 /* The qname can be abbreviated, but h_name is now absolute. */
 207                 qname = he->h_name;
 208         }
 209         ap = hed->host_aliases;
 210         *ap = NULL;
 211         he->h_aliases = hed->host_aliases;
 212         hap = hed->h_addr_ptrs;
 213         *hap = NULL;
 214         he->h_addr_list = hed->h_addr_ptrs;
 215         haveanswer = 0;
 216         had_error = 0;
 217         _dns_ttl_ = -1;
 218         while (ancount-- > 0 && cp < eom && !had_error) {
 219                 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 220                 if ((n < 0) || !(*name_ok)(bp)) {
 221                         had_error++;
 222                         continue;
 223                 }
 224                 cp += n;                        /* name */
 225                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 226                 type = _getshort(cp);
 227                 cp += INT16SZ;                  /* type */
 228                 class = _getshort(cp);
 229                 cp += INT16SZ;                  /* class */
 230                 if (qtype == T_A  && type == T_A)
 231                         _dns_ttl_ = _getlong(cp);
 232                 cp += INT32SZ;                  /* TTL */
 233                 n = _getshort(cp);
 234                 cp += INT16SZ;                  /* len */
 235                 BOUNDS_CHECK(cp, n);
 236                 erdata = cp + n;
 237                 if (class != C_IN) {
 238                         /* XXX - debug? syslog? */
 239                         cp += n;
 240                         continue;               /* XXX - had_error++ ? */
 241                 }
 242                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 243                         if (ap >= &hed->host_aliases[_MAXALIASES-1])
 244                                 continue;
 245                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 246                         if ((n < 0) || !(*name_ok)(tbuf)) {
 247                                 had_error++;
 248                                 continue;
 249                         }
 250                         cp += n;
 251                         if (cp != erdata) {
 252                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 253                                 return (-1);
 254                         }
 255                         /* Store alias. */
 256                         *ap++ = bp;
 257                         n = strlen(bp) + 1;     /* for the \0 */
 258                         if (n >= MAXHOSTNAMELEN) {
 259                                 had_error++;
 260                                 continue;
 261                         }
 262                         bp += n;
 263                         /* Get canonical name. */
 264                         n = strlen(tbuf) + 1;   /* for the \0 */
 265                         if (n > ep - bp || n >= MAXHOSTNAMELEN) {
 266                                 had_error++;
 267                                 continue;
 268                         }
 269                         strcpy(bp, tbuf);
 270                         he->h_name = bp;
 271                         bp += n;
 272                         continue;
 273                 }
 274                 if (qtype == T_PTR && type == T_CNAME) {
 275                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 276                         if (n < 0 || !res_dnok(tbuf)) {
 277                                 had_error++;
 278                                 continue;
 279                         }
 280                         cp += n;
 281                         if (cp != erdata) {
 282                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 283                                 return (-1);
 284                         }
 285                         /* Get canonical name. */
 286                         n = strlen(tbuf) + 1;   /* for the \0 */
 287                         if (n > ep - bp || n >= MAXHOSTNAMELEN) {
 288                                 had_error++;
 289                                 continue;
 290                         }
 291                         strcpy(bp, tbuf);
 292                         tname = bp;
 293                         bp += n;
 294                         continue;
 295                 }
 296                 if (type != qtype) {
 297                         if (type != T_SIG && type != ns_t_dname)
 298                                 syslog(LOG_NOTICE|LOG_AUTH,
 299         "gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
 300                                        qname, p_class(C_IN), p_type(qtype),
 301                                        p_type(type));
 302                         cp += n;
 303                         continue;               /* XXX - had_error++ ? */
 304                 }
 305                 switch (type) {
 306                 case T_PTR:
 307                         if (strcasecmp(tname, bp) != 0) {
 308                                 syslog(LOG_NOTICE|LOG_AUTH,
 309                                        AskedForGot, qname, bp);
 310                                 cp += n;
 311                                 continue;       /* XXX - had_error++ ? */
 312                         }
 313                         n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 314                         if ((n < 0) || !res_hnok(bp)) {
 315                                 had_error++;
 316                                 break;
 317                         }
 318 #if MULTI_PTRS_ARE_ALIASES
 319                         cp += n;
 320                         if (cp != erdata) {
 321                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 322                                 return (-1);
 323                         }
 324                         if (!haveanswer)
 325                                 he->h_name = bp;
 326                         else if (ap < &hed->host_aliases[_MAXALIASES-1])
 327                                 *ap++ = bp;
 328                         else
 329                                 n = -1;
 330                         if (n != -1) {
 331                                 n = strlen(bp) + 1;     /* for the \0 */
 332                                 if (n >= MAXHOSTNAMELEN) {
 333                                         had_error++;
 334                                         break;
 335                                 }
 336                                 bp += n;
 337                         }
 338                         break;
 339 #else
 340                         he->h_name = bp;
 341                         if (statp->options & RES_USE_INET6) {
 342                                 n = strlen(bp) + 1;     /* for the \0 */
 343                                 if (n >= MAXHOSTNAMELEN) {
 344                                         had_error++;
 345                                         break;
 346                                 }
 347                                 bp += n;
 348                                 _map_v4v6_hostent(he, &bp, ep);
 349                         }
 350                         RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 351                         return (0);
 352 #endif
 353                 case T_A:
 354                 case T_AAAA:
 355                         if (strcasecmp(he->h_name, bp) != 0) {
 356                                 syslog(LOG_NOTICE|LOG_AUTH,
 357                                        AskedForGot, he->h_name, bp);
 358                                 cp += n;
 359                                 continue;       /* XXX - had_error++ ? */
 360                         }
 361                         if (n != he->h_length) {
 362                                 cp += n;
 363                                 continue;
 364                         }
 365                         if (!haveanswer) {
 366                                 int nn;
 367
 368                                 he->h_name = bp;
 369                                 nn = strlen(bp) + 1;    /* for the \0 */
 370                                 bp += nn;
 371                         }
 372
 373                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 374
 375                         if (bp + n >= ep) {
 376                                 dprintf("size (%d) too big\n", n, statp);
 377                                 had_error++;
 378                                 continue;
 379                         }
 380                         if (hap >= &hed->h_addr_ptrs[_MAXADDRS-1]) {
 381                                 if (!toobig++)
 382                                         dprintf("Too many addresses (%d)\n",
 383                                                 _MAXADDRS, statp);
 384                                 cp += n;
 385                                 continue;
 386                         }
 387                         memcpy(*hap++ = bp, cp, n);
 388                         bp += n;
 389                         cp += n;
 390                         if (cp != erdata) {
 391                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 392                                 return (-1);
 393                         }
 394                         break;
 395                 default:
 396                         dprintf("Impossible condition (type=%d)\n", type,
 397                             statp);
 398                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 399                         return (-1);
 400                         /* BIND has abort() here, too risky on bad data */
 401                 }
 402                 if (!had_error)
 403                         haveanswer++;
 404         }
 405         if (haveanswer) {
 406                 *ap = NULL;
 407                 *hap = NULL;
 408 # if defined(RESOLVSORT)
 409                 /*
 410                  * Note: we sort even if host can take only one address
 411                  * in its return structures - should give it the "best"
 412                  * address in that case, not some random one
 413                  */
 414                 if (statp->nsort && haveanswer > 1 && qtype == T_A)
 415                         addrsort(hed->h_addr_ptrs, haveanswer, statp);
 416 # endif /*RESOLVSORT*/
 417                 if (!he->h_name) {
 418                         n = strlen(qname) + 1;  /* for the \0 */
 419                         if (n > ep - bp || n >= MAXHOSTNAMELEN)
 420                                 goto no_recovery;
 421                         strcpy(bp, qname);
 422                         he->h_name = bp;
 423                         bp += n;
 424                 }
 425                 if (statp->options & RES_USE_INET6)
 426                         _map_v4v6_hostent(he, &bp, ep);
 427                 RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 428                 return (0);
 429         }
 430  no_recovery:
 431         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 432         return (-1);
 433 }
 434
 435 /* XXX: for async DNS resolver in ypserv */
 436 struct hostent *
 437 __dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
 438 {
 439         struct hostent *he;
 440         struct hostent_data *hed;
 441         int error;
 442         res_state statp;
 443
 444         statp = __res_state();
 445         if ((he = __hostent_init()) == NULL ||
 446             (hed = __hostent_data_init()) == NULL) {
 447                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 448                 return (NULL);
 449         }
 450         switch (qtype) {
 451         case T_AAAA:
 452                 he->h_addrtype = AF_INET6;
 453                 he->h_length = NS_IN6ADDRSZ;
 454                 break;
 455         case T_A:
 456         default:
 457                 he->h_addrtype = AF_INET;
 458                 he->h_length = NS_INADDRSZ;
 459                 break;
 460         }
 461
 462         error = gethostanswer((const querybuf *)answer, anslen, qname, qtype,
 463             he, hed, statp);
 464         return (error == 0) ? he : NULL;
 465 }
 466
 467 int
 468 _dns_gethostbyname(void *rval, void *cb_data, va_list ap)
 469 {
 470         const char *name;
 471         int af;
 472         char *buffer;
 473         size_t buflen;
 474         int *errnop, *h_errnop;
 475         struct hostent *hptr, he;
 476         struct hostent_data *hed;
 477         querybuf *buf;
 478         int n, type, error;
 479         res_state statp;
 480
 481         name = va_arg(ap, const char *);
 482         af = va_arg(ap, int);
 483         hptr = va_arg(ap, struct hostent *);
 484         buffer = va_arg(ap, char *);
 485         buflen = va_arg(ap, size_t);
 486         errnop = va_arg(ap, int *);
 487         h_errnop = va_arg(ap, int *);
 488
 489         *((struct hostent **)rval) = NULL;
 490
 491         statp = __res_state();
 492         if ((hed = __hostent_data_init()) == NULL) {
 493                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 494                 *h_errnop = statp->res_h_errno;
 495                 return (NS_NOTFOUND);
 496         }
 497
 498         he.h_addrtype = af;
 499         switch (af) {
 500         case AF_INET:
 501                 he.h_length = NS_INADDRSZ;
 502                 type = T_A;
 503                 break;
 504         case AF_INET6:
 505                 he.h_length = NS_IN6ADDRSZ;
 506                 type = T_AAAA;
 507                 break;
 508         default:
 509                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 510                 *h_errnop = statp->res_h_errno;
 511                 errno = EAFNOSUPPORT;
 512                 return (NS_UNAVAIL);
 513         }
 514
 515         if ((buf = malloc(sizeof(*buf))) == NULL) {
 516                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 517                 *h_errnop = statp->res_h_errno;
 518                 return (NS_NOTFOUND);
 519         }
 520         n = res_nsearch(statp, name, C_IN, type, buf->buf, sizeof(buf->buf));
 521         if (n < 0) {
 522                 free(buf);
 523                 dprintf("res_nsearch failed (%d)\n", n, statp);
 524                 *h_errnop = statp->res_h_errno;
 525                 return (NS_NOTFOUND);
 526         } else if (n > sizeof(buf->buf)) {
 527                 free(buf);
 528                 dprintf("static buffer is too small (%d)\n", n, statp);
 529                 *h_errnop = statp->res_h_errno;
 530                 return (NS_UNAVAIL);
 531         }
 532         error = gethostanswer(buf, n, name, type, &he, hed, statp);
 533         free(buf);
 534         if (error != 0) {
 535                 *h_errnop = statp->res_h_errno;
 536                 switch (statp->res_h_errno) {
 537                 case HOST_NOT_FOUND:
 538                         return (NS_NOTFOUND);
 539                 case TRY_AGAIN:
 540                         return (NS_TRYAGAIN);
 541                 default:
 542                         return (NS_UNAVAIL);
 543                 }
 544                 /*NOTREACHED*/
 545         }
 546         if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
 547                 *errnop = errno;
 548                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 549                 *h_errnop = statp->res_h_errno;
 550                 return (NS_RETURN);
 551         }
 552         RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 553         *((struct hostent **)rval) = hptr;
 554         return (NS_SUCCESS);
 555 }
 556
 557 int
 558 _dns_gethostbyaddr(void *rval, void *cb_data, va_list ap)
 559 {
 560         const void *addr;
 561         socklen_t len;
 562         int af;
 563         char *buffer;
 564         size_t buflen;
 565         int *errnop, *h_errnop;
 566         const u_char *uaddr;
 567         struct hostent *hptr, he;
 568         struct hostent_data *hed;
 569         int n;
 570         querybuf *buf;
 571         char qbuf[MAXDNAME+1], *qp;
 572         res_state statp;
 573 #ifdef SUNSECURITY
 574         struct hostdata rhd;
 575         struct hostent *rhe;
 576         char **haddr;
 577         u_long old_options;
 578         char hname2[MAXDNAME+1], numaddr[46];
 579         int ret_h_error;
 580 #endif /*SUNSECURITY*/
 581
 582         addr = va_arg(ap, const void *);
 583         len = va_arg(ap, socklen_t);
 584         af = va_arg(ap, int);
 585         hptr = va_arg(ap, struct hostent *);
 586         buffer = va_arg(ap, char *);
 587         buflen = va_arg(ap, size_t);
 588         errnop = va_arg(ap, int *);
 589         h_errnop = va_arg(ap, int *);
 590         uaddr = (const u_char *)addr;
 591
 592         *((struct hostent **)rval) = NULL;
 593
 594         statp = __res_state();
 595         if ((hed = __hostent_data_init()) == NULL) {
 596                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 597                 *h_errnop = statp->res_h_errno;
 598                 return (NS_NOTFOUND);
 599         }
 600
 601         switch (af) {
 602         case AF_INET:
 603                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 604                                (uaddr[3] & 0xff),
 605                                (uaddr[2] & 0xff),
 606                                (uaddr[1] & 0xff),
 607                                (uaddr[0] & 0xff));
 608                 break;
 609         case AF_INET6:
 610                 qp = qbuf;
 611                 for (n = NS_IN6ADDRSZ - 1; n >= 0; n--) {
 612                         qp += SPRINTF((qp, "%x.%x.",
 613                                        uaddr[n] & 0xf,
 614                                        (uaddr[n] >> 4) & 0xf));
 615                 }
 616                 strlcat(qbuf, "ip6.arpa", sizeof(qbuf));
 617                 break;
 618         default:
 619                 abort();
 620         }
 621         if ((buf = malloc(sizeof(*buf))) == NULL) {
 622                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 623                 *h_errnop = statp->res_h_errno;
 624                 return NS_NOTFOUND;
 625         }
 626         n = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf->buf,
 627             sizeof buf->buf);
 628         if (n < 0) {
 629                 free(buf);
 630                 dprintf("res_nquery failed (%d)\n", n, statp);
 631                 *h_errnop = statp->res_h_errno;
 632                 return (NS_UNAVAIL);
 633         }
 634         if (n > sizeof buf->buf) {
 635                 free(buf);
 636                 dprintf("static buffer is too small (%d)\n", n, statp);
 637                 *h_errnop = statp->res_h_errno;
 638                 return (NS_UNAVAIL);
 639         }
 640         if (gethostanswer(buf, n, qbuf, T_PTR, &he, hed, statp) != 0) {
 641                 free(buf);
 642                 *h_errnop = statp->res_h_errno;
 643                 switch (statp->res_h_errno) {
 644                 case HOST_NOT_FOUND:
 645                         return (NS_NOTFOUND);
 646                 case TRY_AGAIN:
 647                         return (NS_TRYAGAIN);
 648                 default:
 649                         return (NS_UNAVAIL);
 650                 }
 651                 /*NOTREACHED*/
 652         }
 653         free(buf);
 654 #ifdef SUNSECURITY
 655         if (af == AF_INET) {
 656             /*
 657              * turn off search as the name should be absolute,
 658              * 'localhost' should be matched by defnames
 659              */
 660             strncpy(hname2, he.h_name, MAXDNAME);
 661             hname2[MAXDNAME] = '\0';
 662             old_options = statp->options;
 663             statp->options &= ~RES_DNSRCH;
 664             statp->options |= RES_DEFNAMES;
 665             memset(&rhd, 0, sizeof rhd);
 666             rhe = gethostbyname_r(hname2, &rhd.host, &rhd.data,
 667                 sizeof(rhd.data), &ret_h_error);
 668             if (rhe == NULL) {
 669                 if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
 670                     strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
 671                 syslog(LOG_NOTICE|LOG_AUTH,
 672                        "gethostbyaddr: No A record for %s (verifying [%s])",
 673                        hname2, numaddr);
 674                 statp->options = old_options;
 675                 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 676                 *h_errnop = statp->res_h_errno;
 677                 return (NS_NOTFOUND);
 678             }
 679             statp->options = old_options;
 680             for (haddr = rhe->h_addr_list; *haddr; haddr++)
 681                 if (!memcmp(*haddr, addr, NS_INADDRSZ))
 682                         break;
 683             if (!*haddr) {
 684                 if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
 685                     strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
 686                 syslog(LOG_NOTICE|LOG_AUTH,
 687                        "gethostbyaddr: A record of %s != PTR record [%s]",
 688                        hname2, numaddr);
 689                 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 690                 *h_errnop = statp->res_h_errno;
 691                 return (NS_NOTFOUND);
 692             }
 693         }
 694 #endif /*SUNSECURITY*/
 695         he.h_addrtype = af;
 696         he.h_length = len;
 697         memcpy(hed->host_addr, uaddr, len);
 698         hed->h_addr_ptrs[0] = (char *)hed->host_addr;
 699         hed->h_addr_ptrs[1] = NULL;
 700         if (af == AF_INET && (statp->options & RES_USE_INET6)) {
 701                 _map_v4v6_address((char*)hed->host_addr, (char*)hed->host_addr);
 702                 he.h_addrtype = AF_INET6;
 703                 he.h_length = NS_IN6ADDRSZ;
 704         }
 705         if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
 706                 *errnop = errno;
 707                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 708                 *h_errnop = statp->res_h_errno;
 709                 return (NS_RETURN);
 710         }
 711         RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 712         *((struct hostent **)rval) = hptr;
 713         return (NS_SUCCESS);
 714 }
 715
 716 #ifdef RESOLVSORT
 717 static void
 718 addrsort(char **ap, int num, res_state res)
 719 {
 720         int i, j;
 721         char **p;
 722         short aval[_MAXADDRS];
 723         int needsort = 0;
 724
 725         p = ap;
 726         for (i = 0; i < num; i++, p++) {
 727             for (j = 0 ; (unsigned)j < res->nsort; j++)
 728                 if (res->sort_list[j].addr.s_addr ==
 729                     (((struct in_addr *)(*p))->s_addr & res->sort_list[j].mask))
 730                         break;
 731             aval[i] = j;
 732             if (needsort == 0 && i > 0 && j < aval[i-1])
 733                 needsort = i;
 734         }
 735         if (!needsort)
 736             return;
 737
 738         while (needsort < num) {
 739             for (j = needsort - 1; j >= 0; j--) {
 740                 if (aval[j] > aval[j+1]) {
 741                     char *hp;
 742
 743                     i = aval[j];
 744                     aval[j] = aval[j+1];
 745                     aval[j+1] = i;
 746
 747                     hp = ap[j];
 748                     ap[j] = ap[j+1];
 749                     ap[j+1] = hp;
 750
 751                 } else
 752                     break;
 753             }
 754             needsort++;
 755         }
 756 }
 757 #endif
 758
 759 void
 760 _sethostdnsent(int stayopen)
 761 {
 762         res_state statp;
 763
 764         statp = __res_state();
 765         if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
 766                 return;
 767         if (stayopen)
 768                 statp->options |= RES_STAYOPEN | RES_USEVC;
 769 }
 770
 771 void
 772 _endhostdnsent()
 773 {
 774         res_state statp;
 775
 776         statp = __res_state();
 777         statp->options &= ~(RES_STAYOPEN | RES_USEVC);
 778         res_nclose(statp);
 779 }