resolv/gethnamaddr.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 /* XXX This file is not used by any of the resolver functions implemented by
  53    glibc (i.e. get*info and gethostby*).  It cannot be removed however because
  54    it exports symbols in the libresolv ABI.  The file is not maintained any
  55    more, nor are these functions.  */
  56
  57 #if defined(LIBC_SCCS) && !defined(lint)
  58 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
  59 #endif /* LIBC_SCCS and not lint */
  60
  61 #include <sys/types.h>
  62 #include <sys/param.h>
  63 #include <sys/socket.h>
  64 #include <netinet/in.h>
  65 #include <arpa/inet.h>
  66 #include <arpa/nameser.h>
  67
  68 #include <stdio.h>
  69 #include <netdb.h>
  70 #include <resolv.h>
  71 #include <ctype.h>
  72 #include <errno.h>
  73 #include <syslog.h>
  74
  75 #define RESOLVSORT
  76
  77 #ifndef LOG_AUTH
  78 # define LOG_AUTH 0
  79 #endif
  80
  81 #define MULTI_PTRS_ARE_ALIASES 1        /* XXX - experimental */
  82
  83 #if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
  84 # include <stdlib.h>
  85 # include <string.h>
  86 #else
  87 # include "../conf/portability.h"
  88 #endif
  89
  90 #if defined(USE_OPTIONS_H)
  91 # include <../conf/options.h>
  92 #endif
  93
  94 #ifdef SPRINTF_CHAR
  95 # define SPRINTF(x) strlen(sprintf/**/x)
  96 #else
  97 # define SPRINTF(x) ((size_t)sprintf x)
  98 #endif
  99
 100 #define MAXALIASES      35
 101 #define MAXADDRS        35
 102
 103 static const char AskedForGot[] =
 104                           "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
 105
 106 static char *h_addr_ptrs[MAXADDRS + 1];
 107
 108 static struct hostent host;
 109 static char *host_aliases[MAXALIASES];
 110 static char hostbuf[8*1024];
 111 static u_char host_addr[16];    /* IPv4 or IPv6 */
 112 static FILE *hostf = NULL;
 113 static int stayopen = 0;
 114
 115 static void map_v4v6_address (const char *src, char *dst) __THROW;
 116 static void map_v4v6_hostent (struct hostent *hp, char **bp, int *len) __THROW;
 117
 118 #ifdef RESOLVSORT
 119 extern void addrsort (char **, int) __THROW;
 120 #endif
 121
 122 #if PACKETSZ > 65536
 123 #define MAXPACKET       PACKETSZ
 124 #else
 125 #define MAXPACKET       65536
 126 #endif
 127
 128 /* As per RFC 1034 and 1035 a host name cannot exceed 255 octets in length.  */
 129 #ifdef MAXHOSTNAMELEN
 130 # undef MAXHOSTNAMELEN
 131 #endif
 132 #define MAXHOSTNAMELEN 256
 133
 134 typedef union {
 135     HEADER hdr;
 136     u_char buf[MAXPACKET];
 137 } querybuf;
 138
 139 typedef union {
 140     int32_t al;
 141     char ac;
 142 } align;
 143
 144 #ifndef h_errno
 145 extern int h_errno;
 146 #endif
 147
 148 #ifdef DEBUG
 149 static void
 150 Dprintf(msg, num)
 151         char *msg;
 152         int num;
 153 {
 154         if (_res.options & RES_DEBUG) {
 155                 int save = errno;
 156
 157                 printf(msg, num);
 158                 __set_errno (save);
 159         }
 160 }
 161 #else
 162 # define Dprintf(msg, num) /*nada*/
 163 #endif
 164
 165 #define BOUNDED_INCR(x) \
 166         do { \
 167                 cp += x; \
 168                 if (cp > eom) { \
 169                         __set_h_errno (NO_RECOVERY); \
 170                         return (NULL); \
 171                 } \
 172         } while (0)
 173
 174 #define BOUNDS_CHECK(ptr, count) \
 175         do { \
 176                 if ((ptr) + (count) > eom) { \
 177                         __set_h_errno (NO_RECOVERY); \
 178                         return (NULL); \
 179                 } \
 180         } while (0)
 181
 182
 183 static struct hostent *
 184 getanswer (const querybuf *answer, int anslen, const char *qname, int qtype)
 185 {
 186         const HEADER *hp;
 187         const u_char *cp;
 188         int n;
 189         const u_char *eom, *erdata;
 190         char *bp, **ap, **hap;
 191         int type, class, buflen, ancount, qdcount;
 192         int haveanswer, had_error;
 193         int toobig = 0;
 194         char tbuf[MAXDNAME];
 195         const char *tname;
 196         int (*name_ok) (const char *);
 197
 198         tname = qname;
 199         host.h_name = NULL;
 200         eom = answer->buf + anslen;
 201         switch (qtype) {
 202         case T_A:
 203         case T_AAAA:
 204                 name_ok = res_hnok;
 205                 break;
 206         case T_PTR:
 207                 name_ok = res_dnok;
 208                 break;
 209         default:
 210                 return (NULL);  /* XXX should be abort(); */
 211         }
 212         /*
 213          * find first satisfactory answer
 214          */
 215         hp = &answer->hdr;
 216         ancount = ntohs(hp->ancount);
 217         qdcount = ntohs(hp->qdcount);
 218         bp = hostbuf;
 219         buflen = sizeof hostbuf;
 220         cp = answer->buf;
 221         BOUNDED_INCR(HFIXEDSZ);
 222         if (qdcount != 1) {
 223                 __set_h_errno (NO_RECOVERY);
 224                 return (NULL);
 225         }
 226         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 227         if ((n < 0) || !(*name_ok)(bp)) {
 228                 __set_h_errno (NO_RECOVERY);
 229                 return (NULL);
 230         }
 231         BOUNDED_INCR(n + QFIXEDSZ);
 232         if (qtype == T_A || qtype == T_AAAA) {
 233                 /* res_send() has already verified that the query name is the
 234                  * same as the one we sent; this just gets the expanded name
 235                  * (i.e., with the succeeding search-domain tacked on).
 236                  */
 237                 n = strlen(bp) + 1;             /* for the \0 */
 238                 if (n >= MAXHOSTNAMELEN) {
 239                         __set_h_errno (NO_RECOVERY);
 240                         return (NULL);
 241                 }
 242                 host.h_name = bp;
 243                 bp += n;
 244                 buflen -= n;
 245                 /* The qname can be abbreviated, but h_name is now absolute. */
 246                 qname = host.h_name;
 247         }
 248         ap = host_aliases;
 249         *ap = NULL;
 250         host.h_aliases = host_aliases;
 251         hap = h_addr_ptrs;
 252         *hap = NULL;
 253         host.h_addr_list = h_addr_ptrs;
 254         haveanswer = 0;
 255         had_error = 0;
 256         while (ancount-- > 0 && cp < eom && !had_error) {
 257                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 258                 if ((n < 0) || !(*name_ok)(bp)) {
 259                         had_error++;
 260                         continue;
 261                 }
 262                 cp += n;                        /* name */
 263                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 264                 type = ns_get16(cp);
 265                 cp += INT16SZ;                  /* type */
 266                 class = ns_get16(cp);
 267                 cp += INT16SZ + INT32SZ;        /* class, TTL */
 268                 n = ns_get16(cp);
 269                 cp += INT16SZ;                  /* len */
 270                 BOUNDS_CHECK(cp, n);
 271                 erdata = cp + n;
 272                 if (class != C_IN) {
 273                         /* XXX - debug? syslog? */
 274                         cp += n;
 275                         continue;               /* XXX - had_error++ ? */
 276                 }
 277                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 278                         if (ap >= &host_aliases[MAXALIASES-1])
 279                                 continue;
 280                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 281                         if ((n < 0) || !(*name_ok)(tbuf)) {
 282                                 had_error++;
 283                                 continue;
 284                         }
 285                         cp += n;
 286                         if (cp != erdata) {
 287                                 __set_h_errno (NO_RECOVERY);
 288                                 return (NULL);
 289                         }
 290                         /* Store alias. */
 291                         *ap++ = bp;
 292                         n = strlen(bp) + 1;     /* for the \0 */
 293                         if (n >= MAXHOSTNAMELEN) {
 294                                 had_error++;
 295                                 continue;
 296                         }
 297                         bp += n;
 298                         buflen -= n;
 299                         /* Get canonical name. */
 300                         n = strlen(tbuf) + 1;   /* for the \0 */
 301                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 302                                 had_error++;
 303                                 continue;
 304                         }
 305                         strcpy(bp, tbuf);
 306                         host.h_name = bp;
 307                         bp += n;
 308                         buflen -= n;
 309                         continue;
 310                 }
 311                 if (qtype == T_PTR && type == T_CNAME) {
 312                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 313                         if (n < 0 || !res_dnok(tbuf)) {
 314                                 had_error++;
 315                                 continue;
 316                         }
 317                         cp += n;
 318                         if (cp != erdata) {
 319                                 __set_h_errno (NO_RECOVERY);
 320                                 return (NULL);
 321                         }
 322                         /* Get canonical name. */
 323                         n = strlen(tbuf) + 1;   /* for the \0 */
 324                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 325                                 had_error++;
 326                                 continue;
 327                         }
 328                         strcpy(bp, tbuf);
 329                         tname = bp;
 330                         bp += n;
 331                         buflen -= n;
 332                         continue;
 333                 }
 334                 if ((type == T_SIG) || (type == T_KEY) || (type == T_NXT)) {
 335                         /* We don't support DNSSEC yet.  For now, ignore
 336                          * the record and send a low priority message
 337                          * to syslog.
 338                          */
 339                         syslog(LOG_DEBUG|LOG_AUTH,
 340                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 341                                qname, p_class(C_IN), p_type(qtype),
 342                                p_type(type));
 343                         cp += n;
 344                         continue;
 345                 }
 346                 if (type != qtype) {
 347                         syslog(LOG_NOTICE|LOG_AUTH,
 348                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 349                                qname, p_class(C_IN), p_type(qtype),
 350                                p_type(type));
 351                         cp += n;
 352                         continue;               /* XXX - had_error++ ? */
 353                 }
 354                 switch (type) {
 355                 case T_PTR:
 356                         if (strcasecmp(tname, bp) != 0) {
 357                                 syslog(LOG_NOTICE|LOG_AUTH,
 358                                        AskedForGot, qname, bp);
 359                                 cp += n;
 360                                 continue;       /* XXX - had_error++ ? */
 361                         }
 362                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 363                         if ((n < 0) || !res_hnok(bp)) {
 364                                 had_error++;
 365                                 break;
 366                         }
 367 #if MULTI_PTRS_ARE_ALIASES
 368                         cp += n;
 369                         if (cp != erdata) {
 370                                 __set_h_errno (NO_RECOVERY);
 371                                 return (NULL);
 372                         }
 373                         if (!haveanswer)
 374                                 host.h_name = bp;
 375                         else if (ap < &host_aliases[MAXALIASES-1])
 376                                 *ap++ = bp;
 377                         else
 378                                 n = -1;
 379                         if (n != -1) {
 380                                 n = strlen(bp) + 1;     /* for the \0 */
 381                                 if (n >= MAXHOSTNAMELEN) {
 382                                         had_error++;
 383                                         break;
 384                                 }
 385                                 bp += n;
 386                                 buflen -= n;
 387                         }
 388                         break;
 389 #else
 390                         host.h_name = bp;
 391                         if (_res.options & RES_USE_INET6) {
 392                                 n = strlen(bp) + 1;     /* for the \0 */
 393                                 if (n >= MAXHOSTNAMELEN) {
 394                                         had_error++;
 395                                         break;
 396                                 }
 397                                 bp += n;
 398                                 buflen -= n;
 399                                 map_v4v6_hostent(&host, &bp, &buflen);
 400                         }
 401                         __set_h_errno (NETDB_SUCCESS);
 402                         return (&host);
 403 #endif
 404                 case T_A:
 405                 case T_AAAA:
 406                         if (strcasecmp(host.h_name, bp) != 0) {
 407                                 syslog(LOG_NOTICE|LOG_AUTH,
 408                                        AskedForGot, host.h_name, bp);
 409                                 cp += n;
 410                                 continue;       /* XXX - had_error++ ? */
 411                         }
 412                         if (n != host.h_length) {
 413                                 cp += n;
 414                                 continue;
 415                         }
 416                         if (!haveanswer) {
 417                                 int nn;
 418
 419                                 host.h_name = bp;
 420                                 nn = strlen(bp) + 1;    /* for the \0 */
 421                                 bp += nn;
 422                                 buflen -= nn;
 423                         }
 424
 425                         /* XXX: when incrementing bp, we have to decrement
 426                          * buflen by the same amount --okir */
 427                         buflen -= sizeof(align) - ((u_long)bp % sizeof(align));
 428
 429                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 430
 431                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 432                                 Dprintf("size (%d) too big\n", n);
 433                                 had_error++;
 434                                 continue;
 435                         }
 436                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 437                                 if (!toobig++) {
 438                                         Dprintf("Too many addresses (%d)\n",
 439                                                 MAXADDRS);
 440                                 }
 441                                 cp += n;
 442                                 continue;
 443                         }
 444                         memmove(*hap++ = bp, cp, n);
 445                         bp += n;
 446                         buflen -= n;
 447                         cp += n;
 448                         if (cp != erdata) {
 449                                 __set_h_errno (NO_RECOVERY);
 450                                 return (NULL);
 451                         }
 452                         break;
 453                 default:
 454                         abort();
 455                 }
 456                 if (!had_error)
 457                         haveanswer++;
 458         }
 459         if (haveanswer) {
 460                 *ap = NULL;
 461                 *hap = NULL;
 462 # if defined(RESOLVSORT)
 463                 /*
 464                  * Note: we sort even if host can take only one address
 465                  * in its return structures - should give it the "best"
 466                  * address in that case, not some random one
 467                  */
 468                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 469                         addrsort(h_addr_ptrs, haveanswer);
 470 # endif /*RESOLVSORT*/
 471                 if (!host.h_name) {
 472                         n = strlen(qname) + 1;  /* for the \0 */
 473                         if (n > buflen || n >= MAXHOSTNAMELEN)
 474                                 goto no_recovery;
 475                         strcpy(bp, qname);
 476                         host.h_name = bp;
 477                         bp += n;
 478                         buflen -= n;
 479                 }
 480                 if (_res.options & RES_USE_INET6)
 481                         map_v4v6_hostent(&host, &bp, &buflen);
 482                 __set_h_errno (NETDB_SUCCESS);
 483                 return (&host);
 484         }
 485  no_recovery:
 486         __set_h_errno (NO_RECOVERY);
 487         return (NULL);
 488 }
 489
 490 extern struct hostent *gethostbyname2(const char *name, int af);
 491 libresolv_hidden_proto (gethostbyname2)
 492
 493 struct hostent *
 494 gethostbyname(name)
 495         const char *name;
 496 {
 497         struct hostent *hp;
 498
 499         if (__res_maybe_init (&_res, 0) == -1) {
 500                 __set_h_errno (NETDB_INTERNAL);
 501                 return (NULL);
 502         }
 503         if (_res.options & RES_USE_INET6) {
 504                 hp = gethostbyname2(name, AF_INET6);
 505                 if (hp)
 506                         return (hp);
 507         }
 508         return (gethostbyname2(name, AF_INET));
 509 }
 510
 511 struct hostent *
 512 gethostbyname2(name, af)
 513         const char *name;
 514         int af;
 515 {
 516         union
 517         {
 518           querybuf *buf;
 519           u_char *ptr;
 520         } buf;
 521         querybuf *origbuf;
 522         const char *cp;
 523         char *bp;
 524         int n, size, type, len;
 525         struct hostent *ret;
 526
 527         if (__res_maybe_init (&_res, 0) == -1) {
 528                 __set_h_errno (NETDB_INTERNAL);
 529                 return (NULL);
 530         }
 531
 532         switch (af) {
 533         case AF_INET:
 534                 size = INADDRSZ;
 535                 type = T_A;
 536                 break;
 537         case AF_INET6:
 538                 size = IN6ADDRSZ;
 539                 type = T_AAAA;
 540                 break;
 541         default:
 542                 __set_h_errno (NETDB_INTERNAL);
 543                 __set_errno (EAFNOSUPPORT);
 544                 return (NULL);
 545         }
 546
 547         host.h_addrtype = af;
 548         host.h_length = size;
 549
 550         /*
 551          * if there aren't any dots, it could be a user-level alias.
 552          * this is also done in res_query() since we are not the only
 553          * function that looks up host names.
 554          */
 555         if (!strchr(name, '.') && (cp = __hostalias(name)))
 556                 name = cp;
 557
 558         /*
 559          * disallow names consisting only of digits/dots, unless
 560          * they end in a dot.
 561          */
 562         if (isdigit(name[0]))
 563                 for (cp = name;; ++cp) {
 564                         if (!*cp) {
 565                                 if (*--cp == '.')
 566                                         break;
 567                                 /*
 568                                  * All-numeric, no dot at the end.
 569                                  * Fake up a hostent as if we'd actually
 570                                  * done a lookup.
 571                                  */
 572                                 if (inet_pton(af, name, host_addr) <= 0) {
 573                                         __set_h_errno (HOST_NOT_FOUND);
 574                                         return (NULL);
 575                                 }
 576                                 strncpy(hostbuf, name, MAXDNAME);
 577                                 hostbuf[MAXDNAME] = '\0';
 578                                 bp = hostbuf + MAXDNAME;
 579                                 len = sizeof hostbuf - MAXDNAME;
 580                                 host.h_name = hostbuf;
 581                                 host.h_aliases = host_aliases;
 582                                 host_aliases[0] = NULL;
 583                                 h_addr_ptrs[0] = (char *)host_addr;
 584                                 h_addr_ptrs[1] = NULL;
 585                                 host.h_addr_list = h_addr_ptrs;
 586                                 if (_res.options & RES_USE_INET6)
 587                                         map_v4v6_hostent(&host, &bp, &len);
 588                                 __set_h_errno (NETDB_SUCCESS);
 589                                 return (&host);
 590                         }
 591                         if (!isdigit(*cp) && *cp != '.')
 592                                 break;
 593                }
 594         if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
 595             name[0] == ':')
 596                 for (cp = name;; ++cp) {
 597                         if (!*cp) {
 598                                 if (*--cp == '.')
 599                                         break;
 600                                 /*
 601                                  * All-IPv6-legal, no dot at the end.
 602                                  * Fake up a hostent as if we'd actually
 603                                  * done a lookup.
 604                                  */
 605                                 if (inet_pton(af, name, host_addr) <= 0) {
 606                                         __set_h_errno (HOST_NOT_FOUND);
 607                                         return (NULL);
 608                                 }
 609                                 strncpy(hostbuf, name, MAXDNAME);
 610                                 hostbuf[MAXDNAME] = '\0';
 611                                 bp = hostbuf + MAXDNAME;
 612                                 len = sizeof hostbuf - MAXDNAME;
 613                                 host.h_name = hostbuf;
 614                                 host.h_aliases = host_aliases;
 615                                 host_aliases[0] = NULL;
 616                                 h_addr_ptrs[0] = (char *)host_addr;
 617                                 h_addr_ptrs[1] = NULL;
 618                                 host.h_addr_list = h_addr_ptrs;
 619                                 __set_h_errno (NETDB_SUCCESS);
 620                                 return (&host);
 621                         }
 622                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
 623                                 break;
 624                 }
 625
 626         buf.buf = origbuf = (querybuf *) alloca (1024);
 627
 628         if ((n = __libc_res_nsearch(&_res, name, C_IN, type, buf.buf->buf, 1024,
 629                                     &buf.ptr, NULL, NULL, NULL, NULL)) < 0) {
 630                 if (buf.buf != origbuf)
 631                         free (buf.buf);
 632                 Dprintf("res_nsearch failed (%d)\n", n);
 633                 if (errno == ECONNREFUSED)
 634                         return (_gethtbyname2(name, af));
 635                 return (NULL);
 636         }
 637         ret = getanswer(buf.buf, n, name, type);
 638         if (buf.buf != origbuf)
 639                 free (buf.buf);
 640         return ret;
 641 }
 642 libresolv_hidden_def (gethostbyname2)
 643
 644 struct hostent *
 645 gethostbyaddr(addr, len, af)
 646         const void *addr;
 647         socklen_t len;
 648         int af;
 649 {
 650         const u_char *uaddr = (const u_char *)addr;
 651         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 652         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 653         int n;
 654         socklen_t size;
 655         union
 656         {
 657           querybuf *buf;
 658           u_char *ptr;
 659         } buf;
 660         querybuf *orig_buf;
 661         struct hostent *hp;
 662         char qbuf[MAXDNAME+1], *qp = NULL;
 663 #ifdef SUNSECURITY
 664         struct hostent *rhp;
 665         char **haddr;
 666         u_long old_options;
 667         char hname2[MAXDNAME+1];
 668 #endif /*SUNSECURITY*/
 669
 670         if (__res_maybe_init (&_res, 0) == -1) {
 671                 __set_h_errno (NETDB_INTERNAL);
 672                 return (NULL);
 673         }
 674         if (af == AF_INET6 && len == IN6ADDRSZ &&
 675             (!memcmp(uaddr, mapped, sizeof mapped) ||
 676              !memcmp(uaddr, tunnelled, sizeof tunnelled))) {
 677                 /* Unmap. */
 678                 addr += sizeof mapped;
 679                 uaddr += sizeof mapped;
 680                 af = AF_INET;
 681                 len = INADDRSZ;
 682         }
 683         switch (af) {
 684         case AF_INET:
 685                 size = INADDRSZ;
 686                 break;
 687         case AF_INET6:
 688                 size = IN6ADDRSZ;
 689                 break;
 690         default:
 691                 __set_errno (EAFNOSUPPORT);
 692                 __set_h_errno (NETDB_INTERNAL);
 693                 return (NULL);
 694         }
 695         if (size != len) {
 696                 __set_errno (EINVAL);
 697                 __set_h_errno (NETDB_INTERNAL);
 698                 return (NULL);
 699         }
 700         switch (af) {
 701         case AF_INET:
 702                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 703                                (uaddr[3] & 0xff),
 704                                (uaddr[2] & 0xff),
 705                                (uaddr[1] & 0xff),
 706                                (uaddr[0] & 0xff));
 707                 break;
 708         case AF_INET6:
 709                 qp = qbuf;
 710                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 711                         qp += SPRINTF((qp, "%x.%x.",
 712                                        uaddr[n] & 0xf,
 713                                        (uaddr[n] >> 4) & 0xf));
 714                 }
 715                 strcpy(qp, "ip6.arpa");
 716                 break;
 717         default:
 718                 abort();
 719         }
 720
 721         buf.buf = orig_buf = (querybuf *) alloca (1024);
 722
 723         n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf, 1024,
 724                               &buf.ptr, NULL, NULL, NULL, NULL);
 725         if (n < 0 && af == AF_INET6 && (_res.options & RES_NOIP6DOTINT) == 0) {
 726                 strcpy(qp, "ip6.int");
 727                 n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf,
 728                                       buf.buf != orig_buf ? MAXPACKET : 1024,
 729                                       &buf.ptr, NULL, NULL, NULL, NULL);
 730         }
 731         if (n < 0) {
 732                 if (buf.buf != orig_buf)
 733                         free (buf.buf);
 734                 Dprintf("res_nquery failed (%d)\n", n);
 735                 if (errno == ECONNREFUSED)
 736                         return (_gethtbyaddr(addr, len, af));
 737                 return (NULL);
 738         }
 739         hp = getanswer(buf.buf, n, qbuf, T_PTR);
 740         if (buf.buf != orig_buf)
 741                 free (buf.buf);
 742         if (!hp)
 743                 return (NULL);  /* h_errno was set by getanswer() */
 744 #ifdef SUNSECURITY
 745         if (af == AF_INET) {
 746             /*
 747              * turn off search as the name should be absolute,
 748              * 'localhost' should be matched by defnames
 749              */
 750             strncpy(hname2, hp->h_name, MAXDNAME);
 751             hname2[MAXDNAME] = '\0';
 752             old_options = _res.options;
 753             _res.options &= ~RES_DNSRCH;
 754             _res.options |= RES_DEFNAMES;
 755             if (!(rhp = gethostbyname(hname2))) {
 756                 syslog(LOG_NOTICE|LOG_AUTH,
 757                        "gethostbyaddr: No A record for %s (verifying [%s])",
 758                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 759                 _res.options = old_options;
 760                 __set_h_errno (HOST_NOT_FOUND);
 761                 return (NULL);
 762             }
 763             _res.options = old_options;
 764             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 765                 if (!memcmp(*haddr, addr, INADDRSZ))
 766                         break;
 767             if (!*haddr) {
 768                 syslog(LOG_NOTICE|LOG_AUTH,
 769                        "gethostbyaddr: A record of %s != PTR record [%s]",
 770                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 771                 __set_h_errno (HOST_NOT_FOUND);
 772                 return (NULL);
 773             }
 774         }
 775 #endif /*SUNSECURITY*/
 776         hp->h_addrtype = af;
 777         hp->h_length = len;
 778         memmove(host_addr, addr, len);
 779         h_addr_ptrs[0] = (char *)host_addr;
 780         h_addr_ptrs[1] = NULL;
 781         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 782                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 783                 hp->h_addrtype = AF_INET6;
 784                 hp->h_length = IN6ADDRSZ;
 785         }
 786         __set_h_errno (NETDB_SUCCESS);
 787         return (hp);
 788 }
 789
 790 void
 791 _sethtent(f)
 792         int f;
 793 {
 794         if (!hostf)
 795                 hostf = fopen(_PATH_HOSTS, "rce" );
 796         else
 797                 rewind(hostf);
 798         stayopen = f;
 799 }
 800 libresolv_hidden_def (_sethtent)
 801
 802 void
 803 _endhtent (void)
 804 {
 805         if (hostf && !stayopen) {
 806                 (void) fclose(hostf);
 807                 hostf = NULL;
 808         }
 809 }
 810
 811 struct hostent *
 812 _gethtent (void)
 813 {
 814         char *p;
 815         char *cp, **q;
 816         int af, len;
 817
 818         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "rce" ))) {
 819                 __set_h_errno (NETDB_INTERNAL);
 820                 return (NULL);
 821         }
 822  again:
 823         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 824                 __set_h_errno (HOST_NOT_FOUND);
 825                 return (NULL);
 826         }
 827         if (*p == '#')
 828                 goto again;
 829         if (!(cp = strpbrk(p, "#\n")))
 830                 goto again;
 831         *cp = '\0';
 832         if (!(cp = strpbrk(p, " \t")))
 833                 goto again;
 834         *cp++ = '\0';
 835         if (inet_pton(AF_INET6, p, host_addr) > 0) {
 836                 af = AF_INET6;
 837                 len = IN6ADDRSZ;
 838         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 839                 if (_res.options & RES_USE_INET6) {
 840                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 841                         af = AF_INET6;
 842                         len = IN6ADDRSZ;
 843                 } else {
 844                         af = AF_INET;
 845                         len = INADDRSZ;
 846                 }
 847         } else {
 848                 goto again;
 849         }
 850         h_addr_ptrs[0] = (char *)host_addr;
 851         h_addr_ptrs[1] = NULL;
 852         host.h_addr_list = h_addr_ptrs;
 853         host.h_length = len;
 854         host.h_addrtype = af;
 855         while (*cp == ' ' || *cp == '\t')
 856                 cp++;
 857         host.h_name = cp;
 858         q = host.h_aliases = host_aliases;
 859         if ((cp = strpbrk(cp, " \t")))
 860                 *cp++ = '\0';
 861         while (cp && *cp) {
 862                 if (*cp == ' ' || *cp == '\t') {
 863                         cp++;
 864                         continue;
 865                 }
 866                 if (q < &host_aliases[MAXALIASES - 1])
 867                         *q++ = cp;
 868                 if ((cp = strpbrk(cp, " \t")))
 869                         *cp++ = '\0';
 870         }
 871         *q = NULL;
 872         __set_h_errno (NETDB_SUCCESS);
 873         return (&host);
 874 }
 875 libresolv_hidden_def (_gethtent)
 876
 877 struct hostent *
 878 _gethtbyname(name)
 879         const char *name;
 880 {
 881         struct hostent *hp;
 882
 883         if (_res.options & RES_USE_INET6) {
 884                 hp = _gethtbyname2(name, AF_INET6);
 885                 if (hp)
 886                         return (hp);
 887         }
 888         return (_gethtbyname2(name, AF_INET));
 889 }
 890
 891 struct hostent *
 892 _gethtbyname2(name, af)
 893         const char *name;
 894         int af;
 895 {
 896         struct hostent *p;
 897         char **cp;
 898
 899         _sethtent(0);
 900         while ((p = _gethtent())) {
 901                 if (p->h_addrtype != af)
 902                         continue;
 903                 if (strcasecmp(p->h_name, name) == 0)
 904                         break;
 905                 for (cp = p->h_aliases; *cp != 0; cp++)
 906                         if (strcasecmp(*cp, name) == 0)
 907                                 goto found;
 908         }
 909  found:
 910         _endhtent();
 911         return (p);
 912 }
 913 libresolv_hidden_def (_gethtbyname2)
 914
 915 struct hostent *
 916 _gethtbyaddr(addr, len, af)
 917         const char *addr;
 918         size_t len;
 919         int af;
 920 {
 921         struct hostent *p;
 922
 923         _sethtent(0);
 924         while ((p = _gethtent()))
 925                 if (p->h_addrtype == af && !memcmp(p->h_addr, addr, len))
 926                         break;
 927         _endhtent();
 928         return (p);
 929 }
 930 libresolv_hidden_def (_gethtbyaddr)
 931
 932 static void
 933 map_v4v6_address(src, dst)
 934         const char *src;
 935         char *dst;
 936 {
 937         u_char *p = (u_char *)dst;
 938         char tmp[INADDRSZ];
 939         int i;
 940
 941         /* Stash a temporary copy so our caller can update in place. */
 942         memcpy(tmp, src, INADDRSZ);
 943         /* Mark this ipv6 addr as a mapped ipv4. */
 944         for (i = 0; i < 10; i++)
 945                 *p++ = 0x00;
 946         *p++ = 0xff;
 947         *p++ = 0xff;
 948         /* Retrieve the saved copy and we're done. */
 949         memcpy((void*)p, tmp, INADDRSZ);
 950 }
 951
 952 static void
 953 map_v4v6_hostent(hp, bpp, lenp)
 954         struct hostent *hp;
 955         char **bpp;
 956         int *lenp;
 957 {
 958         char **ap;
 959
 960         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 961                 return;
 962         hp->h_addrtype = AF_INET6;
 963         hp->h_length = IN6ADDRSZ;
 964         for (ap = hp->h_addr_list; *ap; ap++) {
 965                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 966
 967                 if (*lenp < (i + IN6ADDRSZ)) {
 968                         /* Out of memory.  Truncate address list here.  XXX */
 969                         *ap = NULL;
 970                         return;
 971                 }
 972                 *bpp += i;
 973                 *lenp -= i;
 974                 map_v4v6_address(*ap, *bpp);
 975                 *ap = *bpp;
 976                 *bpp += IN6ADDRSZ;
 977                 *lenp -= IN6ADDRSZ;
 978         }
 979 }
 980
 981 #ifdef RESOLVSORT
 982 extern void
 983 addrsort(ap, num)
 984         char **ap;
 985         int num;
 986 {
 987         int i, j;
 988         char **p;
 989         short aval[MAXADDRS];
 990         int needsort = 0;
 991
 992         p = ap;
 993         for (i = 0; i < num; i++, p++) {
 994             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 995                 if (_res.sort_list[j].addr.s_addr ==
 996                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 997                         break;
 998             aval[i] = j;
 999             if (needsort == 0 && i > 0 && j < aval[i-1])
1000                 needsort = i;
1001         }
1002         if (!needsort)
1003             return;
1004
1005         while (needsort < num) {
1006             for (j = needsort - 1; j >= 0; j--) {
1007                 if (aval[j] > aval[j+1]) {
1008                     char *hp;
1009
1010                     i = aval[j];
1011                     aval[j] = aval[j+1];
1012                     aval[j+1] = i;
1013
1014                     hp = ap[j];
1015                     ap[j] = ap[j+1];
1016                     ap[j+1] = hp;
1017
1018                 } else
1019                     break;
1020             }
1021             needsort++;
1022         }
1023 }
1024 #endif
1025
1026 #if defined(BSD43_BSD43_NFS) || defined(sun)
1027 /* some libc's out there are bound internally to these names (UMIPS) */
1028 void
1029 ht_sethostent(stayopen)
1030         int stayopen;
1031 {
1032         _sethtent(stayopen);
1033 }
1034
1035 void
1036 ht_endhostent (void)
1037 {
1038         _endhtent();
1039 }
1040
1041 struct hostent *
1042 ht_gethostbyname(name)
1043         char *name;
1044 {
1045         return (_gethtbyname(name));
1046 }
1047
1048 struct hostent *
1049 ht_gethostbyaddr(addr, len, af)
1050         const char *addr;
1051         size_t len;
1052         int af;
1053 {
1054         return (_gethtbyaddr(addr, len, af));
1055 }
1056
1057 struct hostent *
1058 gethostent (void)
1059 {
1060         return (_gethtent());
1061 }
1062
1063 void
1064 dns_service (void)
1065 {
1066         return;
1067 }
1068
1069 #undef dn_skipname
1070 dn_skipname(comp_dn, eom)
1071         const u_char *comp_dn, *eom;
1072 {
1073         return (__dn_skipname(comp_dn, eom));
1074 }
1075 #endif /*old-style libc with yp junk in it*/