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  * 3. 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 1.27.2.5 2002/11/02 18:54:57 ume Exp $
  54  * $DragonFly: src/lib/libc/net/gethostbydns.c,v 1.5 2005/09/19 09:34:53 asmodai 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
  74 #include "res_config.h"
  75
  76 #define SPRINTF(x) ((size_t)sprintf x)
  77
  78 #define MAXALIASES      35
  79 #define MAXADDRS        35
  80
  81 static const char AskedForGot[] =
  82                 "gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
  83
  84 static char *h_addr_ptrs[MAXADDRS + 1];
  85
  86 static struct hostent host;
  87 static char *host_aliases[MAXALIASES];
  88 static char hostbuf[8*1024];
  89 static u_char host_addr[16];    /* IPv4 or IPv6 */
  90
  91 #ifdef RESOLVSORT
  92 static void addrsort (char **, int);
  93 #endif
  94
  95 #define MAXPACKET       (64*1024)
  96
  97 typedef union {
  98     HEADER hdr;
  99     u_char buf[MAXPACKET];
 100 } querybuf;
 101
 102 typedef union {
 103     int32_t al;
 104     char ac;
 105 } align;
 106
 107 extern int h_errno;
 108 int _dns_ttl_;
 109
 110 #ifdef DEBUG
 111 static void
 112 dprintf(msg, num)
 113         char *msg;
 114         int num;
 115 {
 116         if (_res.options & RES_DEBUG) {
 117                 int save = errno;
 118
 119                 printf(msg, num);
 120                 errno = save;
 121         }
 122 }
 123 #else
 124 # define dprintf(msg, num) /*nada*/
 125 #endif
 126
 127 #define BOUNDED_INCR(x) \
 128         do { \
 129                 cp += x; \
 130                 if (cp > eom) { \
 131                         h_errno = NO_RECOVERY; \
 132                         return (NULL); \
 133                 } \
 134         } while (0)
 135
 136 #define BOUNDS_CHECK(ptr, count) \
 137         do { \
 138                 if ((ptr) + (count) > eom) { \
 139                         h_errno = NO_RECOVERY; \
 140                         return (NULL); \
 141                 } \
 142         } while (0)
 143
 144 static struct hostent *
 145 gethostanswer(answer, anslen, qname, qtype)
 146         const querybuf *answer;
 147         int anslen;
 148         const char *qname;
 149         int qtype;
 150 {
 151         const HEADER *hp;
 152         const u_char *cp;
 153         int n;
 154         const u_char *eom, *erdata;
 155         char *bp, **ap, **hap;
 156         int type, class, buflen, ancount, qdcount;
 157         int haveanswer, had_error;
 158         int toobig = 0;
 159         char tbuf[MAXDNAME];
 160         const char *tname;
 161         int (*name_ok) (const char *);
 162
 163         tname = qname;
 164         host.h_name = NULL;
 165         eom = answer->buf + anslen;
 166         switch (qtype) {
 167         case T_A:
 168         case T_AAAA:
 169                 name_ok = res_hnok;
 170                 break;
 171         case T_PTR:
 172                 name_ok = res_dnok;
 173                 break;
 174         default:
 175                 h_errno = NO_RECOVERY;
 176                 return (NULL);  /* XXX should be abort(); */
 177         }
 178         /*
 179          * find first satisfactory answer
 180          */
 181         hp = &answer->hdr;
 182         ancount = ntohs(hp->ancount);
 183         qdcount = ntohs(hp->qdcount);
 184         bp = hostbuf;
 185         buflen = sizeof hostbuf;
 186         cp = answer->buf;
 187         BOUNDED_INCR(HFIXEDSZ);
 188         if (qdcount != 1) {
 189                 h_errno = NO_RECOVERY;
 190                 return (NULL);
 191         }
 192         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 193         if ((n < 0) || !(*name_ok)(bp)) {
 194                 h_errno = NO_RECOVERY;
 195                 return (NULL);
 196         }
 197         BOUNDED_INCR(n + QFIXEDSZ);
 198         if (qtype == T_A || qtype == T_AAAA) {
 199                 /* res_send() has already verified that the query name is the
 200                  * same as the one we sent; this just gets the expanded name
 201                  * (i.e., with the succeeding search-domain tacked on).
 202                  */
 203                 n = strlen(bp) + 1;             /* for the \0 */
 204                 if (n >= MAXHOSTNAMELEN) {
 205                         h_errno = NO_RECOVERY;
 206                         return (NULL);
 207                 }
 208                 host.h_name = bp;
 209                 bp += n;
 210                 buflen -= n;
 211                 /* The qname can be abbreviated, but h_name is now absolute. */
 212                 qname = host.h_name;
 213         }
 214         ap = host_aliases;
 215         *ap = NULL;
 216         host.h_aliases = host_aliases;
 217         hap = h_addr_ptrs;
 218         *hap = NULL;
 219         host.h_addr_list = h_addr_ptrs;
 220         haveanswer = 0;
 221         had_error = 0;
 222         _dns_ttl_ = -1;
 223         while (ancount-- > 0 && cp < eom && !had_error) {
 224                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 225                 if ((n < 0) || !(*name_ok)(bp)) {
 226                         had_error++;
 227                         continue;
 228                 }
 229                 cp += n;                        /* name */
 230                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 231                 type = _getshort(cp);
 232                 cp += INT16SZ;                  /* type */
 233                 class = _getshort(cp);
 234                 cp += INT16SZ;                  /* class */
 235                 if (qtype == T_A  && type == T_A)
 236                         _dns_ttl_ = _getlong(cp);
 237                 cp += INT32SZ;                  /* TTL */
 238                 n = _getshort(cp);
 239                 cp += INT16SZ;                  /* len */
 240                 BOUNDS_CHECK(cp, n);
 241                 erdata = cp + n;
 242                 if (class != C_IN) {
 243                         /* XXX - debug? syslog? */
 244                         cp += n;
 245                         continue;               /* XXX - had_error++ ? */
 246                 }
 247                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 248                         if (ap >= &host_aliases[MAXALIASES-1])
 249                                 continue;
 250                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 251                         if ((n < 0) || !(*name_ok)(tbuf)) {
 252                                 had_error++;
 253                                 continue;
 254                         }
 255                         cp += n;
 256                         if (cp != erdata) {
 257                                 h_errno = NO_RECOVERY;
 258                                 return (NULL);
 259                         }
 260                         /* Store alias. */
 261                         *ap++ = bp;
 262                         n = strlen(bp) + 1;     /* for the \0 */
 263                         if (n >= MAXHOSTNAMELEN) {
 264                                 had_error++;
 265                                 continue;
 266                         }
 267                         bp += n;
 268                         buflen -= n;
 269                         /* Get canonical name. */
 270                         n = strlen(tbuf) + 1;   /* for the \0 */
 271                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 272                                 had_error++;
 273                                 continue;
 274                         }
 275                         strcpy(bp, tbuf);
 276                         host.h_name = bp;
 277                         bp += n;
 278                         buflen -= n;
 279                         continue;
 280                 }
 281                 if (qtype == T_PTR && type == T_CNAME) {
 282                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 283                         if (n < 0 || !res_dnok(tbuf)) {
 284                                 had_error++;
 285                                 continue;
 286                         }
 287                         cp += n;
 288                         if (cp != erdata) {
 289                                 h_errno = NO_RECOVERY;
 290                                 return (NULL);
 291                         }
 292                         /* Get canonical name. */
 293                         n = strlen(tbuf) + 1;   /* for the \0 */
 294                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 295                                 had_error++;
 296                                 continue;
 297                         }
 298                         strcpy(bp, tbuf);
 299                         tname = bp;
 300                         bp += n;
 301                         buflen -= n;
 302                         continue;
 303                 }
 304                 if (type != qtype) {
 305                         if (type != T_SIG)
 306                                 syslog(LOG_NOTICE|LOG_AUTH,
 307         "gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
 308                                        qname, p_class(C_IN), p_type(qtype),
 309                                        p_type(type));
 310                         cp += n;
 311                         continue;               /* XXX - had_error++ ? */
 312                 }
 313                 switch (type) {
 314                 case T_PTR:
 315                         if (strcasecmp(tname, bp) != 0) {
 316                                 syslog(LOG_NOTICE|LOG_AUTH,
 317                                        AskedForGot, qname, bp);
 318                                 cp += n;
 319                                 continue;       /* XXX - had_error++ ? */
 320                         }
 321                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 322                         if ((n < 0) || !res_hnok(bp)) {
 323                                 had_error++;
 324                                 break;
 325                         }
 326 #if MULTI_PTRS_ARE_ALIASES
 327                         cp += n;
 328                         if (cp != erdata) {
 329                                 h_errno = NO_RECOVERY;
 330                                 return (NULL);
 331                         }
 332                         if (!haveanswer)
 333                                 host.h_name = bp;
 334                         else if (ap < &host_aliases[MAXALIASES-1])
 335                                 *ap++ = bp;
 336                         else
 337                                 n = -1;
 338                         if (n != -1) {
 339                                 n = strlen(bp) + 1;     /* for the \0 */
 340                                 if (n >= MAXHOSTNAMELEN) {
 341                                         had_error++;
 342                                         break;
 343                                 }
 344                                 bp += n;
 345                                 buflen -= n;
 346                         }
 347                         break;
 348 #else
 349                         host.h_name = bp;
 350                         if (_res.options & RES_USE_INET6) {
 351                                 n = strlen(bp) + 1;     /* for the \0 */
 352                                 if (n >= MAXHOSTNAMELEN) {
 353                                         had_error++;
 354                                         break;
 355                                 }
 356                                 bp += n;
 357                                 buflen -= n;
 358                                 _map_v4v6_hostent(&host, &bp, &buflen);
 359                         }
 360                         h_errno = NETDB_SUCCESS;
 361                         return (&host);
 362 #endif
 363                 case T_A:
 364                 case T_AAAA:
 365                         if (strcasecmp(host.h_name, bp) != 0) {
 366                                 syslog(LOG_NOTICE|LOG_AUTH,
 367                                        AskedForGot, host.h_name, bp);
 368                                 cp += n;
 369                                 continue;       /* XXX - had_error++ ? */
 370                         }
 371                         if (n != host.h_length) {
 372                                 cp += n;
 373                                 continue;
 374                         }
 375                         if (!haveanswer) {
 376                                 int nn;
 377
 378                                 host.h_name = bp;
 379                                 nn = strlen(bp) + 1;    /* for the \0 */
 380                                 bp += nn;
 381                                 buflen -= nn;
 382                         }
 383
 384                         buflen -= sizeof(align) - ((u_long)bp % sizeof(align));
 385                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 386
 387                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 388                                 dprintf("size (%d) too big\n", n);
 389                                 had_error++;
 390                                 continue;
 391                         }
 392                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 393                                 if (!toobig++)
 394                                         dprintf("Too many addresses (%d)\n",
 395                                                 MAXADDRS);
 396                                 cp += n;
 397                                 continue;
 398                         }
 399                         bcopy(cp, *hap++ = bp, n);
 400                         bp += n;
 401                         buflen -= n;
 402                         cp += n;
 403                         if (cp != erdata) {
 404                                 h_errno = NO_RECOVERY;
 405                                 return (NULL);
 406                         }
 407                         break;
 408                 default:
 409                         dprintf("Impossible condition (type=%d)\n", type);
 410                         h_errno = NO_RECOVERY;
 411                         return (NULL);
 412                         /* BIND has abort() here, too risky on bad data */
 413                 }
 414                 if (!had_error)
 415                         haveanswer++;
 416         }
 417         if (haveanswer) {
 418                 *ap = NULL;
 419                 *hap = NULL;
 420 # if defined(RESOLVSORT)
 421                 /*
 422                  * Note: we sort even if host can take only one address
 423                  * in its return structures - should give it the "best"
 424                  * address in that case, not some random one
 425                  */
 426                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 427                         addrsort(h_addr_ptrs, haveanswer);
 428 # endif /*RESOLVSORT*/
 429                 if (!host.h_name) {
 430                         n = strlen(qname) + 1;  /* for the \0 */
 431                         if (n > buflen || n >= MAXHOSTNAMELEN)
 432                                 goto no_recovery;
 433                         strcpy(bp, qname);
 434                         host.h_name = bp;
 435                         bp += n;
 436                         buflen -= n;
 437                 }
 438                 if (_res.options & RES_USE_INET6)
 439                         _map_v4v6_hostent(&host, &bp, &buflen);
 440                 h_errno = NETDB_SUCCESS;
 441                 return (&host);
 442         }
 443  no_recovery:
 444         h_errno = NO_RECOVERY;
 445         return (NULL);
 446 }
 447
 448 struct hostent *
 449 __dns_getanswer(answer, anslen, qname, qtype)
 450         const char *answer;
 451         int anslen;
 452         const char *qname;
 453         int qtype;
 454 {
 455         switch(qtype) {
 456         case T_AAAA:
 457                 host.h_addrtype = AF_INET6;
 458                 host.h_length = IN6ADDRSZ;
 459                 break;
 460         case T_A:
 461         default:
 462                 host.h_addrtype = AF_INET;
 463                 host.h_length = INADDRSZ;
 464                 break;
 465         }
 466
 467         return(gethostanswer((const querybuf *)answer, anslen, qname, qtype));
 468 }
 469
 470 struct hostent *
 471 _gethostbydnsname(name, af)
 472         const char *name;
 473         int af;
 474 {
 475         querybuf *buf;
 476         const char *cp;
 477         char *bp;
 478         int n, size, type, len;
 479         struct hostent *hp;
 480
 481         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 482                 h_errno = NETDB_INTERNAL;
 483                 return (NULL);
 484         }
 485
 486         switch (af) {
 487         case AF_INET:
 488                 size = INADDRSZ;
 489                 type = T_A;
 490                 break;
 491         case AF_INET6:
 492                 size = IN6ADDRSZ;
 493                 type = T_AAAA;
 494                 break;
 495         default:
 496                 h_errno = NETDB_INTERNAL;
 497                 errno = EAFNOSUPPORT;
 498                 return (NULL);
 499         }
 500
 501         host.h_addrtype = af;
 502         host.h_length = size;
 503
 504         /*
 505          * if there aren't any dots, it could be a user-level alias.
 506          * this is also done in res_query() since we are not the only
 507          * function that looks up host names.
 508          */
 509         if (!strchr(name, '.') && (cp = __hostalias(name)))
 510                 name = cp;
 511
 512         /*
 513          * disallow names consisting only of digits/dots, unless
 514          * they end in a dot.
 515          */
 516         if (isdigit((unsigned char)name[0]))
 517                 for (cp = name;; ++cp) {
 518                         if (!*cp) {
 519                                 if (*--cp == '.')
 520                                         break;
 521                                 /*
 522                                  * All-numeric, no dot at the end.
 523                                  * Fake up a hostent as if we'd actually
 524                                  * done a lookup.
 525                                  */
 526                                 if (inet_pton(af, name, host_addr) <= 0) {
 527                                         h_errno = HOST_NOT_FOUND;
 528                                         return (NULL);
 529                                 }
 530                                 strncpy(hostbuf, name, MAXDNAME);
 531                                 hostbuf[MAXDNAME] = '\0';
 532                                 bp = hostbuf + MAXDNAME;
 533                                 len = sizeof hostbuf - MAXDNAME;
 534                                 host.h_name = hostbuf;
 535                                 host.h_aliases = host_aliases;
 536                                 host_aliases[0] = NULL;
 537                                 h_addr_ptrs[0] = (char *)host_addr;
 538                                 h_addr_ptrs[1] = NULL;
 539                                 host.h_addr_list = h_addr_ptrs;
 540                                 if (_res.options & RES_USE_INET6)
 541                                         _map_v4v6_hostent(&host, &bp, &len);
 542                                 h_errno = NETDB_SUCCESS;
 543                                 return (&host);
 544                         }
 545                         if (!isdigit((unsigned char)*cp) && *cp != '.')
 546                                 break;
 547                 }
 548         if ((isxdigit((unsigned char)name[0]) && strchr(name, ':') != NULL) ||
 549             name[0] == ':')
 550                 for (cp = name;; ++cp) {
 551                         if (!*cp) {
 552                                 if (*--cp == '.')
 553                                         break;
 554                                 /*
 555                                  * All-IPv6-legal, no dot at the end.
 556                                  * Fake up a hostent as if we'd actually
 557                                  * done a lookup.
 558                                  */
 559                                 if (inet_pton(af, name, host_addr) <= 0) {
 560                                         h_errno = HOST_NOT_FOUND;
 561                                         return (NULL);
 562                                 }
 563                                 strncpy(hostbuf, name, MAXDNAME);
 564                                 hostbuf[MAXDNAME] = '\0';
 565                                 bp = hostbuf + MAXDNAME;
 566                                 len = sizeof hostbuf - MAXDNAME;
 567                                 host.h_name = hostbuf;
 568                                 host.h_aliases = host_aliases;
 569                                 host_aliases[0] = NULL;
 570                                 h_addr_ptrs[0] = (char *)host_addr;
 571                                 h_addr_ptrs[1] = NULL;
 572                                 host.h_addr_list = h_addr_ptrs;
 573                                 h_errno = NETDB_SUCCESS;
 574                                 return (&host);
 575                         }
 576                         if (!isxdigit((unsigned char)*cp) && *cp != ':' && *cp != '.')
 577                                 break;
 578                 }
 579
 580         if ((buf = malloc(sizeof(*buf))) == NULL) {
 581                 h_errno = NETDB_INTERNAL;
 582                 return (NULL);
 583         }
 584         n = res_search(name, C_IN, type, buf->buf, sizeof(buf->buf));
 585         if (n < 0) {
 586                 free(buf);
 587                 dprintf("res_search failed (%d)\n", n);
 588                 return (NULL);
 589         } else if (n > sizeof(buf->buf)) {
 590                 free(buf);
 591                 dprintf("static buffer is too small (%d)\n", n);
 592                 return (NULL);
 593         }
 594         hp = gethostanswer(buf, n, name, type);
 595         free(buf);
 596         return (hp);
 597 }
 598
 599 struct hostent *
 600 _gethostbydnsaddr(addr, len, af)
 601         const char *addr;       /* XXX should have been def'd as u_char! */
 602         int len, af;
 603 {
 604         const u_char *uaddr = (const u_char *)addr;
 605         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 606         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 607         int n, size;
 608         querybuf *buf;
 609         struct hostent *hp;
 610         char qbuf[MAXDNAME+1], *qp;
 611 #ifdef SUNSECURITY
 612         struct hostent *rhp;
 613         char **haddr;
 614         u_long old_options;
 615         char hname2[MAXDNAME+1];
 616 #endif /*SUNSECURITY*/
 617
 618         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 619                 h_errno = NETDB_INTERNAL;
 620                 return (NULL);
 621         }
 622         if (af == AF_INET6 && len == IN6ADDRSZ &&
 623             (!bcmp(uaddr, mapped, sizeof mapped) ||
 624              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 625                 /* Unmap. */
 626                 addr += sizeof mapped;
 627                 uaddr += sizeof mapped;
 628                 af = AF_INET;
 629                 len = INADDRSZ;
 630         }
 631         switch (af) {
 632         case AF_INET:
 633                 size = INADDRSZ;
 634                 break;
 635         case AF_INET6:
 636                 size = IN6ADDRSZ;
 637                 break;
 638         default:
 639                 errno = EAFNOSUPPORT;
 640                 h_errno = NETDB_INTERNAL;
 641                 return (NULL);
 642         }
 643         if (size != len) {
 644                 errno = EINVAL;
 645                 h_errno = NETDB_INTERNAL;
 646                 return (NULL);
 647         }
 648         switch (af) {
 649         case AF_INET:
 650                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 651                                (uaddr[3] & 0xff),
 652                                (uaddr[2] & 0xff),
 653                                (uaddr[1] & 0xff),
 654                                (uaddr[0] & 0xff));
 655                 break;
 656         case AF_INET6:
 657                 qp = qbuf;
 658                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 659                         qp += SPRINTF((qp, "%x.%x.",
 660                                        uaddr[n] & 0xf,
 661                                        (uaddr[n] >> 4) & 0xf));
 662                 }
 663                 strlcat(qbuf, "ip6.arpa", sizeof(qbuf));
 664                 break;
 665         default:
 666                 abort();
 667         }
 668         if ((buf = malloc(sizeof(*buf))) == NULL) {
 669                 h_errno = NETDB_INTERNAL;
 670                 return (NULL);
 671         }
 672         n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf->buf, sizeof buf->buf);
 673         if (n < 0 && af == AF_INET6) {
 674                 *qp = '\0';
 675                 strlcat(qbuf, "ip6.int", sizeof(qbuf));
 676                 n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf->buf,
 677                               sizeof buf->buf);
 678         }
 679         if (n < 0) {
 680                 free(buf);
 681                 dprintf("res_query failed (%d)\n", n);
 682                 return (NULL);
 683         }
 684         if (n > sizeof buf->buf) {
 685                 free(buf);
 686                 dprintf("static buffer is too small (%d)\n", n);
 687                 return (NULL);
 688         }
 689         if (!(hp = gethostanswer(buf, n, qbuf, T_PTR))) {
 690                 free(buf);
 691                 return (NULL);  /* h_errno was set by gethostanswer() */
 692         }
 693         free(buf);
 694 #ifdef SUNSECURITY
 695         if (af == AF_INET) {
 696             /*
 697              * turn off search as the name should be absolute,
 698              * 'localhost' should be matched by defnames
 699              */
 700             strncpy(hname2, hp->h_name, MAXDNAME);
 701             hname2[MAXDNAME] = '\0';
 702             old_options = _res.options;
 703             _res.options &= ~RES_DNSRCH;
 704             _res.options |= RES_DEFNAMES;
 705             if (!(rhp = gethostbyname(hname2))) {
 706                 syslog(LOG_NOTICE|LOG_AUTH,
 707                        "gethostbyaddr: No A record for %s (verifying [%s])",
 708                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 709                 _res.options = old_options;
 710                 h_errno = HOST_NOT_FOUND;
 711                 return (NULL);
 712             }
 713             _res.options = old_options;
 714             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 715                 if (!memcmp(*haddr, addr, INADDRSZ))
 716                         break;
 717             if (!*haddr) {
 718                 syslog(LOG_NOTICE|LOG_AUTH,
 719                        "gethostbyaddr: A record of %s != PTR record [%s]",
 720                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 721                 h_errno = HOST_NOT_FOUND;
 722                 return (NULL);
 723             }
 724         }
 725 #endif /*SUNSECURITY*/
 726         hp->h_addrtype = af;
 727         hp->h_length = len;
 728         bcopy(addr, host_addr, len);
 729         h_addr_ptrs[0] = (char *)host_addr;
 730         h_addr_ptrs[1] = NULL;
 731         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 732                 _map_v4v6_address((char*)host_addr, (char*)host_addr);
 733                 hp->h_addrtype = AF_INET6;
 734                 hp->h_length = IN6ADDRSZ;
 735         }
 736         h_errno = NETDB_SUCCESS;
 737         return (hp);
 738 }
 739
 740 #ifdef RESOLVSORT
 741 static void
 742 addrsort(ap, num)
 743         char **ap;
 744         int num;
 745 {
 746         int i, j;
 747         char **p;
 748         short aval[MAXADDRS];
 749         int needsort = 0;
 750
 751         p = ap;
 752         for (i = 0; i < num; i++, p++) {
 753             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 754                 if (_res.sort_list[j].addr.s_addr ==
 755                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 756                         break;
 757             aval[i] = j;
 758             if (needsort == 0 && i > 0 && j < aval[i-1])
 759                 needsort = i;
 760         }
 761         if (!needsort)
 762             return;
 763
 764         while (needsort < num) {
 765             for (j = needsort - 1; j >= 0; j--) {
 766                 if (aval[j] > aval[j+1]) {
 767                     char *hp;
 768
 769                     i = aval[j];
 770                     aval[j] = aval[j+1];
 771                     aval[j+1] = i;
 772
 773                     hp = ap[j];
 774                     ap[j] = ap[j+1];
 775                     ap[j+1] = hp;
 776
 777                 } else
 778                     break;
 779             }
 780             needsort++;
 781         }
 782 }
 783 #endif
 784 void
 785 _sethostdnsent(stayopen)
 786         int stayopen;
 787 {
 788         if ((_res.options & RES_INIT) == 0 && res_init() == -1)
 789                 return;
 790         if (stayopen)
 791                 _res.options |= RES_STAYOPEN | RES_USEVC;
 792 }
 793
 794 void
 795 _endhostdnsent()
 796 {
 797         _res.options &= ~(RES_STAYOPEN | RES_USEVC);
 798         res_close();
 799 }