StdLib/BsdSocketLib/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  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  * -
  35  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  36  *
  37  * Permission to use, copy, modify, and distribute this software for any
  38  * purpose with or without fee is hereby granted, provided that the above
  39  * copyright notice and this permission notice appear in all copies, and that
  40  * the name of Digital Equipment Corporation not be used in advertising or
  41  * publicity pertaining to distribution of the document or software without
  42  * specific, written prior permission.
  43  *
  44  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  45  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  46  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  47  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  48  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  49  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  50  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  51  * SOFTWARE.
  52  * -
  53  * --Copyright--
  54  */
  55
  56 /*
  57  * Portions copyright (c) 1999, 2000
  58  * Intel Corporation.
  59  * All rights reserved.
  60  *
  61  * Redistribution and use in source and binary forms, with or without
  62  * modification, are permitted provided that the following conditions
  63  * are met:
  64  *
  65  * 1. Redistributions of source code must retain the above copyright
  66  *    notice, this list of conditions and the following disclaimer.
  67  *
  68  * 2. Redistributions in binary form must reproduce the above copyright
  69  *    notice, this list of conditions and the following disclaimer in the
  70  *    documentation and/or other materials provided with the distribution.
  71  *
  72  * 3. All advertising materials mentioning features or use of this software
  73  *    must display the following acknowledgement:
  74  *
  75  *    This product includes software developed by Intel Corporation and
  76  *    its contributors.
  77  *
  78  * 4. Neither the name of Intel Corporation or its contributors may be
  79  *    used to endorse or promote products derived from this software
  80  *    without specific prior written permission.
  81  *
  82  * THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION AND CONTRIBUTORS ``AS IS''
  83  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  84  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  85  * ARE DISCLAIMED.  IN NO EVENT SHALL INTEL CORPORATION OR CONTRIBUTORS BE
  86  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  87  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  88  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  89  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  90  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  91  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  92  * THE POSSIBILITY OF SUCH DAMAGE.
  93  *
  94  */
  95
  96 #if defined(LIBC_SCCS) && !defined(lint)
  97 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
  98 static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $";
  99 static char rcsid[] = "$Id: gethostbydns.c,v 1.1.1.1 2003/11/19 01:51:27 kyu3 Exp $";
 100 #endif /* LIBC_SCCS and not lint */
 101
 102 #include <sys/types.h>
 103 #include <sys/param.h>
 104 #include <sys/socket.h>
 105 #include <netinet/in.h>
 106 #include <arpa/inet.h>
 107 #include <arpa/nameser.h>
 108
 109 #include <stdio.h>
 110 #include <unistd.h>
 111 #include <string.h>
 112 #include <netdb.h>
 113 #include <resolv.h>
 114 #include <ctype.h>
 115 #include <errno.h>
 116 #ifdef _ORG_FREEBSD_
 117 #include <syslog.h>
 118 #else
 119 #include <stdlib.h>
 120 u_int32_t _getlong(const u_char *src);
 121 u_int16_t _getshort(const u_char *src);
 122 #endif
 123
 124 #include "res_config.h"
 125 #include "Socklib_internals.h"
 126
 127 #define SPRINTF(x) ((size_t)sprintf x)
 128
 129 #define MAXALIASES      35
 130 #define MAXADDRS        35
 131
 132 #ifdef _ORG_FREEBSD_
 133 static const char AskedForGot[] =
 134                 "gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
 135 #endif
 136
 137 static char *h_addr_ptrs[MAXADDRS + 1];
 138
 139 static struct hostent host;
 140 static char *host_aliases[MAXALIASES];
 141 static char hostbuf[8*1024];
 142 static u_char host_addr[16];    /* IPv4 or IPv6 */
 143
 144 #ifdef RESOLVSORT
 145 static void addrsort(char **, int);
 146 #endif
 147
 148 #if PACKETSZ > 1024
 149 #define MAXPACKET       PACKETSZ
 150 #else
 151 #define MAXPACKET       1024
 152 #endif
 153
 154 typedef union {
 155     HEADER hdr;
 156     u_char buf[MAXPACKET];
 157 } querybuf;
 158
 159 typedef union {
 160     int32_t al;
 161     char ac;
 162 } align;
 163
 164 extern int h_errno;
 165 int _dns_ttl_;
 166
 167 #ifdef DEBUG_RES
 168 static void
 169 dprintf(char *msg, int num)
 170 {
 171         if (_res.options & RES_DEBUG) {
 172                 int save = errno;
 173
 174                 printf(msg, num);
 175                 errno = save;
 176         }
 177 }
 178 #else
 179 # define dprintf(msg, num) /*nada*/
 180 #endif
 181
 182 #define BOUNDED_INCR(x) \
 183         do { \
 184                 cp += x; \
 185                 if (cp > eom) { \
 186                         h_errno = NO_RECOVERY; \
 187                         return (NULL); \
 188                 } \
 189         } while (0)
 190
 191 #define BOUNDS_CHECK(ptr, count) \
 192         do { \
 193                 if ((ptr) + (count) > eom) { \
 194                         h_errno = NO_RECOVERY; \
 195                         return (NULL); \
 196                 } \
 197         } while (0)
 198
 199 static struct hostent *
 200 gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype)
 201 {
 202         register const HEADER *hp;
 203         register const u_char *cp;
 204         register int n;
 205         const u_char *eom, *erdata;
 206         char *bp, **ap, **hap;
 207         int type, class, buflen, ancount, qdcount;
 208         int haveanswer, had_error;
 209         int toobig = 0;
 210         char tbuf[MAXDNAME];
 211         const char *tname;
 212         int (*name_ok)(const char *);
 213
 214         tname = qname;
 215         host.h_name = NULL;
 216         eom = answer->buf + anslen;
 217         switch (qtype) {
 218         case T_A:
 219         case T_AAAA:
 220                 name_ok = res_hnok;
 221                 break;
 222         case T_PTR:
 223                 name_ok = res_dnok;
 224                 break;
 225         default:
 226                 h_errno = NO_RECOVERY;
 227                 return (NULL);  /* XXX should be abort(); */
 228         }
 229         /*
 230          * find first satisfactory answer
 231          */
 232         hp = &answer->hdr;
 233         ancount = ntohs(hp->ancount);
 234         qdcount = ntohs(hp->qdcount);
 235         bp = hostbuf;
 236         buflen = sizeof hostbuf;
 237         cp = answer->buf;
 238         BOUNDED_INCR(HFIXEDSZ);
 239         if (qdcount != 1) {
 240                 h_errno = NO_RECOVERY;
 241                 return (NULL);
 242         }
 243         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 244         if ((n < 0) || !(*name_ok)(bp)) {
 245                 h_errno = NO_RECOVERY;
 246                 return (NULL);
 247         }
 248         BOUNDED_INCR(n + QFIXEDSZ);
 249         if (qtype == T_A || qtype == T_AAAA) {
 250                 /* res_send() has already verified that the query name is the
 251                  * same as the one we sent; this just gets the expanded name
 252                  * (i.e., with the succeeding search-domain tacked on).
 253                  */
 254                 n = (int)strlen(bp) + 1;                /* for the \0 */
 255                 if (n >= MAXHOSTNAMELEN) {
 256                         h_errno = NO_RECOVERY;
 257                         return (NULL);
 258                 }
 259                 host.h_name = bp;
 260                 bp += n;
 261                 buflen -= n;
 262                 /* The qname can be abbreviated, but h_name is now absolute. */
 263                 qname = host.h_name;
 264         }
 265         ap = host_aliases;
 266         *ap = NULL;
 267         host.h_aliases = host_aliases;
 268         hap = h_addr_ptrs;
 269         *hap = NULL;
 270         host.h_addr_list = h_addr_ptrs;
 271         haveanswer = 0;
 272         had_error = 0;
 273         _dns_ttl_ = -1;
 274         while (ancount-- > 0 && cp < eom && !had_error) {
 275                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 276                 if ((n < 0) || !(*name_ok)(bp)) {
 277                         had_error++;
 278                         continue;
 279                 }
 280                 cp += n;                        /* name */
 281                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 282                 type = _getshort(cp);
 283                 cp += INT16SZ;                  /* type */
 284                 class = _getshort(cp);
 285                 cp += INT16SZ;                  /* class */
 286                 if (qtype == T_A  && type == T_A)
 287                         _dns_ttl_ = _getlong(cp);
 288                 cp += INT32SZ;                  /* TTL */
 289                 n = _getshort(cp);
 290                 cp += INT16SZ;                  /* len */
 291                 BOUNDS_CHECK(cp, n);
 292                 erdata = cp + n;
 293                 if (class != C_IN) {
 294                         /* XXX - debug? syslog? */
 295                         cp += n;
 296                         continue;               /* XXX - had_error++ ? */
 297                 }
 298                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 299                         if (ap >= &host_aliases[MAXALIASES-1])
 300                                 continue;
 301                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 302                         if ((n < 0) || !(*name_ok)(tbuf)) {
 303                                 had_error++;
 304                                 continue;
 305                         }
 306                         cp += n;
 307                         if (cp != erdata) {
 308                                 h_errno = NO_RECOVERY;
 309                                 return (NULL);
 310                         }
 311                         /* Store alias. */
 312                         *ap++ = bp;
 313                         n = (int)strlen(bp) + 1;        /* for the \0 */
 314                         if (n >= MAXHOSTNAMELEN) {
 315                                 had_error++;
 316                                 continue;
 317                         }
 318                         bp += n;
 319                         buflen -= n;
 320                         /* Get canonical name. */
 321                         n = (int)strlen(tbuf) + 1;      /* for the \0 */
 322                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 323                                 had_error++;
 324                                 continue;
 325                         }
 326                         strcpy(bp, tbuf);
 327                         host.h_name = bp;
 328                         bp += n;
 329                         buflen -= n;
 330                         continue;
 331                 }
 332                 if (qtype == T_PTR && type == T_CNAME) {
 333                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 334                         if (n < 0 || !res_dnok(tbuf)) {
 335                                 had_error++;
 336                                 continue;
 337                         }
 338                         cp += n;
 339                         if (cp != erdata) {
 340                                 h_errno = NO_RECOVERY;
 341                                 return (NULL);
 342                         }
 343                         /* Get canonical name. */
 344                         n = (int)strlen(tbuf) + 1;      /* for the \0 */
 345                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 346                                 had_error++;
 347                                 continue;
 348                         }
 349                         strcpy(bp, tbuf);
 350                         tname = bp;
 351                         bp += n;
 352                         buflen -= n;
 353                         continue;
 354                 }
 355                 if (type != qtype) {
 356 #ifdef _ORG_FREEBSD_
 357                         syslog(LOG_NOTICE|LOG_AUTH,
 358         "gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
 359                                qname, p_class(C_IN), p_type(qtype),
 360                                p_type(type));
 361 #endif
 362                         cp += n;
 363                         continue;               /* XXX - had_error++ ? */
 364                 }
 365                 switch (type) {
 366                 case T_PTR:
 367                         if (strcasecmp(tname, bp) != 0) {
 368 #ifdef _ORG_FREEBSD_
 369                                 syslog(LOG_NOTICE|LOG_AUTH,
 370                                        AskedForGot, qname, bp);
 371 #endif
 372                                 cp += n;
 373                                 continue;       /* XXX - had_error++ ? */
 374                         }
 375                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 376                         if ((n < 0) || !res_hnok(bp)) {
 377                                 had_error++;
 378                                 break;
 379                         }
 380 #if MULTI_PTRS_ARE_ALIASES
 381                         cp += n;
 382                         if (cp != erdata) {
 383                                 h_errno = NO_RECOVERY;
 384                                 return (NULL);
 385                         }
 386                         if (!haveanswer)
 387                                 host.h_name = bp;
 388                         else if (ap < &host_aliases[MAXALIASES-1])
 389                                 *ap++ = bp;
 390                         else
 391                                 n = -1;
 392                         if (n != -1) {
 393                                 n = (int)strlen(bp) + 1;        /* for the \0 */
 394                                 if (n >= MAXHOSTNAMELEN) {
 395                                         had_error++;
 396                                         break;
 397                                 }
 398                                 bp += n;
 399                                 buflen -= n;
 400                         }
 401                         break;
 402 #else
 403                         host.h_name = bp;
 404                         if (_res.options & RES_USE_INET6) {
 405                                 n = strlen(bp) + 1;     /* for the \0 */
 406                                 if (n >= MAXHOSTNAMELEN) {
 407                                         had_error++;
 408                                         break;
 409                                 }
 410                                 bp += n;
 411                                 buflen -= n;
 412                                 _map_v4v6_hostent(&host, &bp, &buflen);
 413                         }
 414                         h_errno = NETDB_SUCCESS;
 415                         return (&host);
 416 #endif
 417                 case T_A:
 418                 case T_AAAA:
 419                         if (strcasecmp(host.h_name, bp) != 0) {
 420 #ifdef _ORG_FREEBSD_
 421                                 syslog(LOG_NOTICE|LOG_AUTH,
 422                                        AskedForGot, host.h_name, bp);
 423 #endif
 424                                 cp += n;
 425                                 continue;       /* XXX - had_error++ ? */
 426                         }
 427                         if (n != host.h_length) {
 428                                 cp += n;
 429                                 continue;
 430                         }
 431                         if (!haveanswer) {
 432                                 register int nn;
 433
 434                                 host.h_name = bp;
 435                                 nn = (int)strlen(bp) + 1;       /* for the \0 */
 436                                 bp += nn;
 437                                 buflen -= nn;
 438                         }
 439
 440                         bp += sizeof(align) - ((size_t)bp % sizeof(align));
 441
 442                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 443                                 dprintf("size (%d) too big\n", n);
 444                                 had_error++;
 445                                 continue;
 446                         }
 447                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 448                                 if (!toobig++)
 449                                         dprintf("Too many addresses (%d)\n",
 450                                                 MAXADDRS);
 451                                 cp += n;
 452                                 continue;
 453                         }
 454       *hap++ = bp;
 455                         bcopy(cp, bp, n);
 456                         bp += n;
 457                         buflen -= n;
 458                         cp += n;
 459                         if (cp != erdata) {
 460                                 h_errno = NO_RECOVERY;
 461                                 return (NULL);
 462                         }
 463                         break;
 464                 default:
 465                         dprintf("Impossible condition (type=%d)\n", type);
 466                         h_errno = NO_RECOVERY;
 467                         return (NULL);
 468                         /* BIND has abort() here, too risky on bad data */
 469                 }
 470                 if (!had_error)
 471                         haveanswer++;
 472         }
 473         if (haveanswer) {
 474                 *ap = NULL;
 475                 *hap = NULL;
 476 # if defined(RESOLVSORT)
 477                 /*
 478                  * Note: we sort even if host can take only one address
 479                  * in its return structures - should give it the "best"
 480                  * address in that case, not some random one
 481                  */
 482                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 483                         addrsort(h_addr_ptrs, haveanswer);
 484 # endif /*RESOLVSORT*/
 485                 if (!host.h_name) {
 486                         n = (int)strlen(qname) + 1;     /* for the \0 */
 487                         if (n > buflen || n >= MAXHOSTNAMELEN)
 488                                 goto no_recovery;
 489                         strcpy(bp, qname);
 490                         host.h_name = bp;
 491                         bp += n;
 492                         buflen -= n;
 493                 }
 494                 if (_res.options & RES_USE_INET6)
 495                         _map_v4v6_hostent(&host, &bp, &buflen);
 496                 h_errno = NETDB_SUCCESS;
 497                 return (&host);
 498         }
 499  no_recovery:
 500         h_errno = NO_RECOVERY;
 501         return (NULL);
 502 }
 503
 504 struct hostent *
 505 __dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
 506 {
 507         switch(qtype) {
 508         case T_AAAA:
 509                 host.h_addrtype = AF_INET6;
 510                 host.h_length = IN6ADDRSZ;
 511                 break;
 512         case T_A:
 513         default:
 514                 host.h_addrtype = AF_INET;
 515                 host.h_length = INADDRSZ;
 516                 break;
 517         }
 518
 519         return(gethostanswer((const querybuf *)answer, anslen, qname, qtype));
 520 }
 521
 522 struct hostent *
 523 _gethostbydnsname(const char *name, int af)
 524 {
 525         querybuf buf;
 526         register const char *cp;
 527         char *bp;
 528         int n, size, type, len;
 529
 530         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 531                 h_errno = NETDB_INTERNAL;
 532                 return (NULL);
 533         }
 534
 535         switch (af) {
 536         case AF_INET:
 537                 size = INADDRSZ;
 538                 type = T_A;
 539                 break;
 540         case AF_INET6:
 541                 size = IN6ADDRSZ;
 542                 type = T_AAAA;
 543                 break;
 544         default:
 545                 h_errno = NETDB_INTERNAL;
 546                 errno = EAFNOSUPPORT;
 547                 return (NULL);
 548         }
 549
 550         host.h_addrtype = af;
 551         host.h_length = size;
 552
 553         /*
 554          * if there aren't any dots, it could be a user-level alias.
 555          * this is also done in res_query() since we are not the only
 556          * function that looks up host names.
 557          */
 558         if (!strchr(name, '.') && ( NULL != (cp = __hostalias(name))))
 559                 name = cp;
 560
 561         /*
 562          * disallow names consisting only of digits/dots, unless
 563          * they end in a dot.
 564          */
 565         if (isdigit(name[0]))
 566                 for (cp = name;; ++cp) {
 567                         if (!*cp) {
 568                                 if (*--cp == '.')
 569                                         break;
 570                                 /*
 571                                  * All-numeric, no dot at the end.
 572                                  * Fake up a hostent as if we'd actually
 573                                  * done a lookup.
 574                                  */
 575                                 if (inet_pton(af, name, host_addr) <= 0) {
 576                                         h_errno = HOST_NOT_FOUND;
 577                                         return (NULL);
 578                                 }
 579                                 strncpy(hostbuf, name, MAXDNAME);
 580                                 hostbuf[MAXDNAME] = '\0';
 581                                 bp = hostbuf + MAXDNAME;
 582                                 len = sizeof hostbuf - MAXDNAME;
 583                                 host.h_name = hostbuf;
 584                                 host.h_aliases = host_aliases;
 585                                 host_aliases[0] = NULL;
 586                                 h_addr_ptrs[0] = (char *)host_addr;
 587                                 h_addr_ptrs[1] = NULL;
 588                                 host.h_addr_list = h_addr_ptrs;
 589                                 if (_res.options & RES_USE_INET6)
 590                                         _map_v4v6_hostent(&host, &bp, &len);
 591                                 h_errno = NETDB_SUCCESS;
 592                                 return (&host);
 593                         }
 594                         if (!isdigit(*cp) && *cp != '.')
 595                                 break;
 596                 }
 597         if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
 598             name[0] == ':')
 599                 for (cp = name;; ++cp) {
 600                         if (!*cp) {
 601                                 if (*--cp == '.')
 602                                         break;
 603                                 /*
 604                                  * All-IPv6-legal, no dot at the end.
 605                                  * Fake up a hostent as if we'd actually
 606                                  * done a lookup.
 607                                  */
 608                                 if (inet_pton(af, name, host_addr) <= 0) {
 609                                         h_errno = HOST_NOT_FOUND;
 610                                         return (NULL);
 611                                 }
 612                                 strncpy(hostbuf, name, MAXDNAME);
 613                                 hostbuf[MAXDNAME] = '\0';
 614                                 bp = hostbuf + MAXDNAME;
 615                                 len = sizeof hostbuf - MAXDNAME;
 616                                 host.h_name = hostbuf;
 617                                 host.h_aliases = host_aliases;
 618                                 host_aliases[0] = NULL;
 619                                 h_addr_ptrs[0] = (char *)host_addr;
 620                                 h_addr_ptrs[1] = NULL;
 621                                 host.h_addr_list = h_addr_ptrs;
 622                                 h_errno = NETDB_SUCCESS;
 623                                 return (&host);
 624                         }
 625                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
 626                                 break;
 627                 }
 628
 629         if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) {
 630                 dprintf("res_search failed (%d)\n", n);
 631                 return (NULL);
 632         }
 633         return (gethostanswer(&buf, n, name, type));
 634 }
 635
 636 struct hostent *
 637 _gethostbydnsaddr(const char *addr, int len, int af)
 638 {
 639         const u_char *uaddr = (const u_char *)addr;
 640         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 641         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 642         int n, size;
 643         querybuf buf;
 644         register struct hostent *hp;
 645         char qbuf[MAXDNAME+1], *qp;
 646 #ifdef SUNSECURITY
 647         register struct hostent *rhp;
 648         char **haddr;
 649         u_long old_options;
 650         char hname2[MAXDNAME+1];
 651 #endif /*SUNSECURITY*/
 652
 653         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 654                 h_errno = NETDB_INTERNAL;
 655                 return (NULL);
 656         }
 657         if (af == AF_INET6 && len == IN6ADDRSZ &&
 658             (!bcmp(uaddr, mapped, sizeof mapped) ||
 659              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 660                 /* Unmap. */
 661                 addr += sizeof mapped;
 662                 uaddr += sizeof mapped;
 663                 af = AF_INET;
 664                 len = INADDRSZ;
 665         }
 666         switch (af) {
 667         case AF_INET:
 668                 size = INADDRSZ;
 669                 break;
 670         case AF_INET6:
 671                 size = IN6ADDRSZ;
 672                 break;
 673         default:
 674                 errno = EAFNOSUPPORT;
 675                 h_errno = NETDB_INTERNAL;
 676                 return (NULL);
 677         }
 678         if (size != len) {
 679                 errno = EINVAL;
 680                 h_errno = NETDB_INTERNAL;
 681                 return (NULL);
 682         }
 683         switch (af) {
 684         case AF_INET:
 685                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 686                                (uaddr[3] & 0xff),
 687                                (uaddr[2] & 0xff),
 688                                (uaddr[1] & 0xff),
 689                                (uaddr[0] & 0xff));
 690                 break;
 691         case AF_INET6:
 692                 qp = qbuf;
 693                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 694                         qp += SPRINTF((qp, "%x.%x.",
 695                                        uaddr[n] & 0xf,
 696                                        (uaddr[n] >> 4) & 0xf));
 697                 }
 698                 strcpy(qp, "ip6.int");
 699                 break;
 700         default:
 701                 abort();
 702         }
 703         n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
 704         if (n < 0) {
 705                 dprintf("res_query failed (%d)\n", n);
 706                 return (NULL);
 707         }
 708         if ( NULL == (hp = gethostanswer(&buf, n, qbuf, T_PTR)))
 709                 return (NULL);  /* h_errno was set by gethostanswer() */
 710 #ifdef SUNSECURITY
 711         if (af == AF_INET) {
 712             /*
 713              * turn off search as the name should be absolute,
 714              * 'localhost' should be matched by defnames
 715              */
 716             strncpy(hname2, hp->h_name, MAXDNAME);
 717             hname2[MAXDNAME] = '\0';
 718             old_options = _res.options;
 719             _res.options &= ~RES_DNSRCH;
 720             _res.options |= RES_DEFNAMES;
 721             if (!(rhp = gethostbyname(hname2))) {
 722 #ifdef _ORG_FREEBSD_
 723                 syslog(LOG_NOTICE|LOG_AUTH,
 724                        "gethostbyaddr: No A record for %s (verifying [%s])",
 725                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 726 #endif
 727                 _res.options = old_options;
 728                 h_errno = HOST_NOT_FOUND;
 729                 return (NULL);
 730             }
 731             _res.options = old_options;
 732             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 733                 if (!memcmp(*haddr, addr, INADDRSZ))
 734                         break;
 735             if (!*haddr) {
 736 #ifdef _ORG_FREEBSD_
 737                 syslog(LOG_NOTICE|LOG_AUTH,
 738                        "gethostbyaddr: A record of %s != PTR record [%s]",
 739                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 740 #endif
 741                 h_errno = HOST_NOT_FOUND;
 742                 return (NULL);
 743             }
 744         }
 745 #endif /*SUNSECURITY*/
 746         hp->h_addrtype = af;
 747         hp->h_length = len;
 748         bcopy(addr, host_addr, len);
 749         h_addr_ptrs[0] = (char *)host_addr;
 750         h_addr_ptrs[1] = NULL;
 751         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 752                 _map_v4v6_address((char*)host_addr, (char*)host_addr);
 753                 hp->h_addrtype = AF_INET6;
 754                 hp->h_length = IN6ADDRSZ;
 755         }
 756         h_errno = NETDB_SUCCESS;
 757         return (hp);
 758 }
 759
 760 #ifdef RESOLVSORT
 761 static void
 762 addrsort(char **ap, int num)
 763 {
 764         short i, j;
 765         char **p;
 766         short aval[MAXADDRS];
 767         short needsort = 0;
 768
 769         p = ap;
 770         for (i = 0; i < num; i++, p++) {
 771             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 772                 if (_res.sort_list[j].addr.s_addr ==
 773                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 774                         break;
 775             aval[i] = j;
 776             if (needsort == 0 && i > 0 && j < aval[i-1])
 777                 needsort = i;
 778         }
 779         if (!needsort)
 780             return;
 781
 782         while (needsort < num) {
 783             for (j = needsort - 1; j >= 0; j--) {
 784                 if (aval[j] > aval[j+1]) {
 785                     char *hp;
 786
 787                     i = aval[j];
 788                     aval[j] = aval[j+1];
 789                     aval[j+1] = i;
 790
 791                     hp = ap[j];
 792                     ap[j] = ap[j+1];
 793                     ap[j+1] = hp;
 794
 795                 } else
 796                     break;
 797             }
 798             needsort++;
 799         }
 800 }
 801 #endif
 802 void
 803 _sethostdnsent(int stayopen)
 804 {
 805         if ((_res.options & RES_INIT) == 0 && res_init() == -1)
 806                 return;
 807         if (stayopen)
 808                 _res.options |= RES_STAYOPEN | RES_USEVC;
 809 }
 810
 811 void
 812 _endhostdnsent()
 813 {
 814         _res.options &= ~(RES_STAYOPEN | RES_USEVC);
 815         res_close();
 816 }