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 #if defined(LIBC_SCCS) && !defined(lint)
  53 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
  54 #endif /* LIBC_SCCS and not lint */
  55
  56 #include <sys/types.h>
  57 #include <sys/param.h>
  58 #include <sys/socket.h>
  59 #include <netinet/in.h>
  60 #include <arpa/inet.h>
  61 #include <arpa/nameser.h>
  62
  63 #include <stdio.h>
  64 #include <netdb.h>
  65 #include <resolv.h>
  66 #include <ctype.h>
  67 #include <errno.h>
  68 #include <syslog.h>
  69
  70 #define RESOLVSORT
  71
  72 #ifndef LOG_AUTH
  73 # define LOG_AUTH 0
  74 #endif
  75
  76 #define MULTI_PTRS_ARE_ALIASES 1        /* XXX - experimental */
  77
  78 #if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
  79 # include <stdlib.h>
  80 # include <string.h>
  81 #else
  82 # include "../conf/portability.h"
  83 #endif
  84
  85 #if defined(USE_OPTIONS_H)
  86 # include <../conf/options.h>
  87 #endif
  88
  89 #ifdef SPRINTF_CHAR
  90 # define SPRINTF(x) strlen(sprintf/**/x)
  91 #else
  92 # define SPRINTF(x) ((size_t)sprintf x)
  93 #endif
  94
  95 #define MAXALIASES      35
  96 #define MAXADDRS        35
  97
  98 static const char AskedForGot[] =
  99                           "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
 100
 101 static char *h_addr_ptrs[MAXADDRS + 1];
 102
 103 static struct hostent host;
 104 static char *host_aliases[MAXALIASES];
 105 static char hostbuf[8*1024];
 106 static u_char host_addr[16];    /* IPv4 or IPv6 */
 107 static FILE *hostf = NULL;
 108 static int stayopen = 0;
 109
 110 static void map_v4v6_address (const char *src, char *dst) __THROW;
 111 static void map_v4v6_hostent (struct hostent *hp, char **bp, int *len) __THROW;
 112
 113 #ifdef RESOLVSORT
 114 extern void addrsort (char **, int) __THROW;
 115 #endif
 116
 117 #if PACKETSZ > 65536
 118 #define MAXPACKET       PACKETSZ
 119 #else
 120 #define MAXPACKET       65536
 121 #endif
 122
 123 /* As per RFC 1034 and 1035 a host name cannot exceed 255 octets in length.  */
 124 #ifdef MAXHOSTNAMELEN
 125 # undef MAXHOSTNAMELEN
 126 #endif
 127 #define MAXHOSTNAMELEN 256
 128
 129 typedef union {
 130     HEADER hdr;
 131     u_char buf[MAXPACKET];
 132 } querybuf;
 133
 134 typedef union {
 135     int32_t al;
 136     char ac;
 137 } align;
 138
 139 #ifndef h_errno
 140 extern int h_errno;
 141 #endif
 142
 143 #ifdef DEBUG
 144 static void
 145 Dprintf(msg, num)
 146         char *msg;
 147         int num;
 148 {
 149         if (_res.options & RES_DEBUG) {
 150                 int save = errno;
 151
 152                 printf(msg, num);
 153                 __set_errno (save);
 154         }
 155 }
 156 #else
 157 # define Dprintf(msg, num) /*nada*/
 158 #endif
 159
 160 #define BOUNDED_INCR(x) \
 161         do { \
 162                 cp += x; \
 163                 if (cp > eom) { \
 164                         __set_h_errno (NO_RECOVERY); \
 165                         return (NULL); \
 166                 } \
 167         } while (0)
 168
 169 #define BOUNDS_CHECK(ptr, count) \
 170         do { \
 171                 if ((ptr) + (count) > eom) { \
 172                         __set_h_errno (NO_RECOVERY); \
 173                         return (NULL); \
 174                 } \
 175         } while (0)
 176
 177
 178 static struct hostent *
 179 getanswer(answer, anslen, qname, qtype)
 180         const querybuf *answer;
 181         int anslen;
 182         const char *qname;
 183         int qtype;
 184 {
 185         register const HEADER *hp;
 186         register const u_char *cp;
 187         register int n;
 188         const u_char *eom, *erdata;
 189         char *bp, **ap, **hap;
 190         int type, class, buflen, ancount, qdcount;
 191         int haveanswer, had_error;
 192         int toobig = 0;
 193         char tbuf[MAXDNAME];
 194         const char *tname;
 195         int (*name_ok) (const char *);
 196
 197         tname = qname;
 198         host.h_name = NULL;
 199         eom = answer->buf + anslen;
 200         switch (qtype) {
 201         case T_A:
 202         case T_AAAA:
 203                 name_ok = res_hnok;
 204                 break;
 205         case T_PTR:
 206                 name_ok = res_dnok;
 207                 break;
 208         default:
 209                 return (NULL);  /* XXX should be abort(); */
 210         }
 211         /*
 212          * find first satisfactory answer
 213          */
 214         hp = &answer->hdr;
 215         ancount = ntohs(hp->ancount);
 216         qdcount = ntohs(hp->qdcount);
 217         bp = hostbuf;
 218         buflen = sizeof hostbuf;
 219         cp = answer->buf;
 220         BOUNDED_INCR(HFIXEDSZ);
 221         if (qdcount != 1) {
 222                 __set_h_errno (NO_RECOVERY);
 223                 return (NULL);
 224         }
 225         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 226         if ((n < 0) || !(*name_ok)(bp)) {
 227                 __set_h_errno (NO_RECOVERY);
 228                 return (NULL);
 229         }
 230         BOUNDED_INCR(n + QFIXEDSZ);
 231         if (qtype == T_A || qtype == T_AAAA) {
 232                 /* res_send() has already verified that the query name is the
 233                  * same as the one we sent; this just gets the expanded name
 234                  * (i.e., with the succeeding search-domain tacked on).
 235                  */
 236                 n = strlen(bp) + 1;             /* for the \0 */
 237                 if (n >= MAXHOSTNAMELEN) {
 238                         __set_h_errno (NO_RECOVERY);
 239                         return (NULL);
 240                 }
 241                 host.h_name = bp;
 242                 bp += n;
 243                 buflen -= n;
 244                 /* The qname can be abbreviated, but h_name is now absolute. */
 245                 qname = host.h_name;
 246         }
 247         ap = host_aliases;
 248         *ap = NULL;
 249         host.h_aliases = host_aliases;
 250         hap = h_addr_ptrs;
 251         *hap = NULL;
 252         host.h_addr_list = h_addr_ptrs;
 253         haveanswer = 0;
 254         had_error = 0;
 255         while (ancount-- > 0 && cp < eom && !had_error) {
 256                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 257                 if ((n < 0) || !(*name_ok)(bp)) {
 258                         had_error++;
 259                         continue;
 260                 }
 261                 cp += n;                        /* name */
 262                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 263                 type = ns_get16(cp);
 264                 cp += INT16SZ;                  /* type */
 265                 class = ns_get16(cp);
 266                 cp += INT16SZ + INT32SZ;        /* class, TTL */
 267                 n = ns_get16(cp);
 268                 cp += INT16SZ;                  /* len */
 269                 BOUNDS_CHECK(cp, n);
 270                 erdata = cp + n;
 271                 if (class != C_IN) {
 272                         /* XXX - debug? syslog? */
 273                         cp += n;
 274                         continue;               /* XXX - had_error++ ? */
 275                 }
 276                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 277                         if (ap >= &host_aliases[MAXALIASES-1])
 278                                 continue;
 279                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 280                         if ((n < 0) || !(*name_ok)(tbuf)) {
 281                                 had_error++;
 282                                 continue;
 283                         }
 284                         cp += n;
 285                         if (cp != erdata) {
 286                                 __set_h_errno (NO_RECOVERY);
 287                                 return (NULL);
 288                         }
 289                         /* Store alias. */
 290                         *ap++ = bp;
 291                         n = strlen(bp) + 1;     /* for the \0 */
 292                         if (n >= MAXHOSTNAMELEN) {
 293                                 had_error++;
 294                                 continue;
 295                         }
 296                         bp += n;
 297                         buflen -= n;
 298                         /* Get canonical name. */
 299                         n = strlen(tbuf) + 1;   /* for the \0 */
 300                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 301                                 had_error++;
 302                                 continue;
 303                         }
 304                         strcpy(bp, tbuf);
 305                         host.h_name = bp;
 306                         bp += n;
 307                         buflen -= n;
 308                         continue;
 309                 }
 310                 if (qtype == T_PTR && type == T_CNAME) {
 311                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 312                         if (n < 0 || !res_dnok(tbuf)) {
 313                                 had_error++;
 314                                 continue;
 315                         }
 316                         cp += n;
 317                         if (cp != erdata) {
 318                                 __set_h_errno (NO_RECOVERY);
 319                                 return (NULL);
 320                         }
 321                         /* Get canonical name. */
 322                         n = strlen(tbuf) + 1;   /* for the \0 */
 323                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 324                                 had_error++;
 325                                 continue;
 326                         }
 327                         strcpy(bp, tbuf);
 328                         tname = bp;
 329                         bp += n;
 330                         buflen -= n;
 331                         continue;
 332                 }
 333                 if ((type == T_SIG) || (type == T_KEY) || (type == T_NXT)) {
 334                         /* We don't support DNSSEC yet.  For now, ignore
 335                          * the record and send a low priority message
 336                          * to syslog.
 337                          */
 338                         syslog(LOG_DEBUG|LOG_AUTH,
 339                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 340                                qname, p_class(C_IN), p_type(qtype),
 341                                p_type(type));
 342                         cp += n;
 343                         continue;
 344                 }
 345                 if (type != qtype) {
 346                         syslog(LOG_NOTICE|LOG_AUTH,
 347                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 348                                qname, p_class(C_IN), p_type(qtype),
 349                                p_type(type));
 350                         cp += n;
 351                         continue;               /* XXX - had_error++ ? */
 352                 }
 353                 switch (type) {
 354                 case T_PTR:
 355                         if (strcasecmp(tname, bp) != 0) {
 356                                 syslog(LOG_NOTICE|LOG_AUTH,
 357                                        AskedForGot, qname, bp);
 358                                 cp += n;
 359                                 continue;       /* XXX - had_error++ ? */
 360                         }
 361                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 362                         if ((n < 0) || !res_hnok(bp)) {
 363                                 had_error++;
 364                                 break;
 365                         }
 366 #if MULTI_PTRS_ARE_ALIASES
 367                         cp += n;
 368                         if (cp != erdata) {
 369                                 __set_h_errno (NO_RECOVERY);
 370                                 return (NULL);
 371                         }
 372                         if (!haveanswer)
 373                                 host.h_name = bp;
 374                         else if (ap < &host_aliases[MAXALIASES-1])
 375                                 *ap++ = bp;
 376                         else
 377                                 n = -1;
 378                         if (n != -1) {
 379                                 n = strlen(bp) + 1;     /* for the \0 */
 380                                 if (n >= MAXHOSTNAMELEN) {
 381                                         had_error++;
 382                                         break;
 383                                 }
 384                                 bp += n;
 385                                 buflen -= n;
 386                         }
 387                         break;
 388 #else
 389                         host.h_name = bp;
 390                         if (_res.options & RES_USE_INET6) {
 391                                 n = strlen(bp) + 1;     /* for the \0 */
 392                                 if (n >= MAXHOSTNAMELEN) {
 393                                         had_error++;
 394                                         break;
 395                                 }
 396                                 bp += n;
 397                                 buflen -= n;
 398                                 map_v4v6_hostent(&host, &bp, &buflen);
 399                         }
 400                         __set_h_errno (NETDB_SUCCESS);
 401                         return (&host);
 402 #endif
 403                 case T_A:
 404                 case T_AAAA:
 405                         if (strcasecmp(host.h_name, bp) != 0) {
 406                                 syslog(LOG_NOTICE|LOG_AUTH,
 407                                        AskedForGot, host.h_name, bp);
 408                                 cp += n;
 409                                 continue;       /* XXX - had_error++ ? */
 410                         }
 411                         if (n != host.h_length) {
 412                                 cp += n;
 413                                 continue;
 414                         }
 415                         if (!haveanswer) {
 416                                 register int nn;
 417
 418                                 host.h_name = bp;
 419                                 nn = strlen(bp) + 1;    /* for the \0 */
 420                                 bp += nn;
 421                                 buflen -= nn;
 422                         }
 423
 424                         /* XXX: when incrementing bp, we have to decrement
 425                          * buflen by the same amount --okir */
 426                         buflen -= sizeof(align) - ((u_long)bp % sizeof(align));
 427
 428                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 429
 430                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 431                                 Dprintf("size (%d) too big\n", n);
 432                                 had_error++;
 433                                 continue;
 434                         }
 435                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 436                                 if (!toobig++) {
 437                                         Dprintf("Too many addresses (%d)\n",
 438                                                 MAXADDRS);
 439                                 }
 440                                 cp += n;
 441                                 continue;
 442                         }
 443                         memmove(*hap++ = bp, cp, n);
 444                         bp += n;
 445                         buflen -= n;
 446                         cp += n;
 447                         if (cp != erdata) {
 448                                 __set_h_errno (NO_RECOVERY);
 449                                 return (NULL);
 450                         }
 451                         break;
 452                 default:
 453                         abort();
 454                 }
 455                 if (!had_error)
 456                         haveanswer++;
 457         }
 458         if (haveanswer) {
 459                 *ap = NULL;
 460                 *hap = NULL;
 461 # if defined(RESOLVSORT)
 462                 /*
 463                  * Note: we sort even if host can take only one address
 464                  * in its return structures - should give it the "best"
 465                  * address in that case, not some random one
 466                  */
 467                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 468                         addrsort(h_addr_ptrs, haveanswer);
 469 # endif /*RESOLVSORT*/
 470                 if (!host.h_name) {
 471                         n = strlen(qname) + 1;  /* for the \0 */
 472                         if (n > buflen || n >= MAXHOSTNAMELEN)
 473                                 goto no_recovery;
 474                         strcpy(bp, qname);
 475                         host.h_name = bp;
 476                         bp += n;
 477                         buflen -= n;
 478                 }
 479                 if (_res.options & RES_USE_INET6)
 480                         map_v4v6_hostent(&host, &bp, &buflen);
 481                 __set_h_errno (NETDB_SUCCESS);
 482                 return (&host);
 483         }
 484  no_recovery:
 485         __set_h_errno (NO_RECOVERY);
 486         return (NULL);
 487 }
 488
 489 extern struct hostent *gethostbyname2(const char *name, int af);
 490 libresolv_hidden_proto (gethostbyname2)
 491
 492 struct hostent *
 493 gethostbyname(name)
 494         const char *name;
 495 {
 496         struct hostent *hp;
 497
 498         if (__res_maybe_init (&_res, 0) == -1) {
 499                 __set_h_errno (NETDB_INTERNAL);
 500                 return (NULL);
 501         }
 502         if (_res.options & RES_USE_INET6) {
 503                 hp = gethostbyname2(name, AF_INET6);
 504                 if (hp)
 505                         return (hp);
 506         }
 507         return (gethostbyname2(name, AF_INET));
 508 }
 509
 510 struct hostent *
 511 gethostbyname2(name, af)
 512         const char *name;
 513         int af;
 514 {
 515         union
 516         {
 517           querybuf *buf;
 518           u_char *ptr;
 519         } buf;
 520         querybuf *origbuf;
 521         register const char *cp;
 522         char *bp;
 523         int n, size, type, len;
 524         struct hostent *ret;
 525         extern struct hostent *_gethtbyname2();
 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)) < 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         register struct hostent *hp;
 662         char qbuf[MAXDNAME+1], *qp = NULL;
 663 #ifdef SUNSECURITY
 664         register struct hostent *rhp;
 665         char **haddr;
 666         u_long old_options;
 667         char hname2[MAXDNAME+1];
 668 #endif /*SUNSECURITY*/
 669         extern struct hostent *_gethtbyaddr();
 670
 671         if (__res_maybe_init (&_res, 0) == -1) {
 672                 __set_h_errno (NETDB_INTERNAL);
 673                 return (NULL);
 674         }
 675         if (af == AF_INET6 && len == IN6ADDRSZ &&
 676             (!bcmp(uaddr, mapped, sizeof mapped) ||
 677              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 678                 /* Unmap. */
 679                 addr += sizeof mapped;
 680                 uaddr += sizeof mapped;
 681                 af = AF_INET;
 682                 len = INADDRSZ;
 683         }
 684         switch (af) {
 685         case AF_INET:
 686                 size = INADDRSZ;
 687                 break;
 688         case AF_INET6:
 689                 size = IN6ADDRSZ;
 690                 break;
 691         default:
 692                 __set_errno (EAFNOSUPPORT);
 693                 __set_h_errno (NETDB_INTERNAL);
 694                 return (NULL);
 695         }
 696         if (size != len) {
 697                 __set_errno (EINVAL);
 698                 __set_h_errno (NETDB_INTERNAL);
 699                 return (NULL);
 700         }
 701         switch (af) {
 702         case AF_INET:
 703                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 704                                (uaddr[3] & 0xff),
 705                                (uaddr[2] & 0xff),
 706                                (uaddr[1] & 0xff),
 707                                (uaddr[0] & 0xff));
 708                 break;
 709         case AF_INET6:
 710                 qp = qbuf;
 711                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 712                         qp += SPRINTF((qp, "%x.%x.",
 713                                        uaddr[n] & 0xf,
 714                                        (uaddr[n] >> 4) & 0xf));
 715                 }
 716                 strcpy(qp, "ip6.arpa");
 717                 break;
 718         default:
 719                 abort();
 720         }
 721
 722         buf.buf = orig_buf = (querybuf *) alloca (1024);
 723
 724         n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf, 1024,
 725                               &buf.ptr);
 726         if (n < 0 && af == AF_INET6 && (_res.options & RES_NOIP6DOTINT) == 0) {
 727                 strcpy(qp, "ip6.int");
 728                 n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf,
 729                                       buf.buf != orig_buf ? MAXPACKET : 1024,
 730                                       &buf.ptr);
 731         }
 732         if (n < 0) {
 733                 if (buf.buf != orig_buf)
 734                         free (buf.buf);
 735                 Dprintf("res_nquery failed (%d)\n", n);
 736                 if (errno == ECONNREFUSED)
 737                         return (_gethtbyaddr(addr, len, af));
 738                 return (NULL);
 739         }
 740         hp = getanswer(buf.buf, n, qbuf, T_PTR);
 741         if (buf.buf != orig_buf)
 742                 free (buf.buf);
 743         if (!hp)
 744                 return (NULL);  /* h_errno was set by getanswer() */
 745 #ifdef SUNSECURITY
 746         if (af == AF_INET) {
 747             /*
 748              * turn off search as the name should be absolute,
 749              * 'localhost' should be matched by defnames
 750              */
 751             strncpy(hname2, hp->h_name, MAXDNAME);
 752             hname2[MAXDNAME] = '\0';
 753             old_options = _res.options;
 754             _res.options &= ~RES_DNSRCH;
 755             _res.options |= RES_DEFNAMES;
 756             if (!(rhp = gethostbyname(hname2))) {
 757                 syslog(LOG_NOTICE|LOG_AUTH,
 758                        "gethostbyaddr: No A record for %s (verifying [%s])",
 759                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 760                 _res.options = old_options;
 761                 __set_h_errno (HOST_NOT_FOUND);
 762                 return (NULL);
 763             }
 764             _res.options = old_options;
 765             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 766                 if (!memcmp(*haddr, addr, INADDRSZ))
 767                         break;
 768             if (!*haddr) {
 769                 syslog(LOG_NOTICE|LOG_AUTH,
 770                        "gethostbyaddr: A record of %s != PTR record [%s]",
 771                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 772                 __set_h_errno (HOST_NOT_FOUND);
 773                 return (NULL);
 774             }
 775         }
 776 #endif /*SUNSECURITY*/
 777         hp->h_addrtype = af;
 778         hp->h_length = len;
 779         memmove(host_addr, addr, len);
 780         h_addr_ptrs[0] = (char *)host_addr;
 781         h_addr_ptrs[1] = NULL;
 782         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 783                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 784                 hp->h_addrtype = AF_INET6;
 785                 hp->h_length = IN6ADDRSZ;
 786         }
 787         __set_h_errno (NETDB_SUCCESS);
 788         return (hp);
 789 }
 790
 791 void
 792 _sethtent(f)
 793         int f;
 794 {
 795         if (!hostf)
 796                 hostf = fopen(_PATH_HOSTS, "r" );
 797         else
 798                 rewind(hostf);
 799         stayopen = f;
 800 }
 801 libresolv_hidden_def (_sethtent)
 802
 803 void
 804 _endhtent()
 805 {
 806         if (hostf && !stayopen) {
 807                 (void) fclose(hostf);
 808                 hostf = NULL;
 809         }
 810 }
 811
 812 struct hostent *
 813 _gethtent()
 814 {
 815         char *p;
 816         register char *cp, **q;
 817         int af, len;
 818
 819         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
 820                 __set_h_errno (NETDB_INTERNAL);
 821                 return (NULL);
 822         }
 823  again:
 824         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 825                 __set_h_errno (HOST_NOT_FOUND);
 826                 return (NULL);
 827         }
 828         if (*p == '#')
 829                 goto again;
 830         if (!(cp = strpbrk(p, "#\n")))
 831                 goto again;
 832         *cp = '\0';
 833         if (!(cp = strpbrk(p, " \t")))
 834                 goto again;
 835         *cp++ = '\0';
 836         if (inet_pton(AF_INET6, p, host_addr) > 0) {
 837                 af = AF_INET6;
 838                 len = IN6ADDRSZ;
 839         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 840                 if (_res.options & RES_USE_INET6) {
 841                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 842                         af = AF_INET6;
 843                         len = IN6ADDRSZ;
 844                 } else {
 845                         af = AF_INET;
 846                         len = INADDRSZ;
 847                 }
 848         } else {
 849                 goto again;
 850         }
 851         h_addr_ptrs[0] = (char *)host_addr;
 852         h_addr_ptrs[1] = NULL;
 853         host.h_addr_list = h_addr_ptrs;
 854         host.h_length = len;
 855         host.h_addrtype = af;
 856         while (*cp == ' ' || *cp == '\t')
 857                 cp++;
 858         host.h_name = cp;
 859         q = host.h_aliases = host_aliases;
 860         if ((cp = strpbrk(cp, " \t")))
 861                 *cp++ = '\0';
 862         while (cp && *cp) {
 863                 if (*cp == ' ' || *cp == '\t') {
 864                         cp++;
 865                         continue;
 866                 }
 867                 if (q < &host_aliases[MAXALIASES - 1])
 868                         *q++ = cp;
 869                 if ((cp = strpbrk(cp, " \t")))
 870                         *cp++ = '\0';
 871         }
 872         *q = NULL;
 873         __set_h_errno (NETDB_SUCCESS);
 874         return (&host);
 875 }
 876 libresolv_hidden_def (_gethtent)
 877
 878 struct hostent *
 879 _gethtbyname(name)
 880         const char *name;
 881 {
 882         extern struct hostent *_gethtbyname2();
 883         struct hostent *hp;
 884
 885         if (_res.options & RES_USE_INET6) {
 886                 hp = _gethtbyname2(name, AF_INET6);
 887                 if (hp)
 888                         return (hp);
 889         }
 890         return (_gethtbyname2(name, AF_INET));
 891 }
 892
 893 struct hostent *
 894 _gethtbyname2(name, af)
 895         const char *name;
 896         int af;
 897 {
 898         register struct hostent *p;
 899         register char **cp;
 900
 901         _sethtent(0);
 902         while ((p = _gethtent())) {
 903                 if (p->h_addrtype != af)
 904                         continue;
 905                 if (strcasecmp(p->h_name, name) == 0)
 906                         break;
 907                 for (cp = p->h_aliases; *cp != 0; cp++)
 908                         if (strcasecmp(*cp, name) == 0)
 909                                 goto found;
 910         }
 911  found:
 912         _endhtent();
 913         return (p);
 914 }
 915 libresolv_hidden_def (_gethtbyname2)
 916
 917 struct hostent *
 918 _gethtbyaddr(addr, len, af)
 919         const char *addr;
 920         size_t len;
 921         int af;
 922 {
 923         register struct hostent *p;
 924
 925         _sethtent(0);
 926         while ((p = _gethtent()))
 927                 if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
 928                         break;
 929         _endhtent();
 930         return (p);
 931 }
 932 libresolv_hidden_def (_gethtbyaddr)
 933
 934 static void
 935 map_v4v6_address(src, dst)
 936         const char *src;
 937         char *dst;
 938 {
 939         u_char *p = (u_char *)dst;
 940         char tmp[INADDRSZ];
 941         int i;
 942
 943         /* Stash a temporary copy so our caller can update in place. */
 944         memcpy(tmp, src, INADDRSZ);
 945         /* Mark this ipv6 addr as a mapped ipv4. */
 946         for (i = 0; i < 10; i++)
 947                 *p++ = 0x00;
 948         *p++ = 0xff;
 949         *p++ = 0xff;
 950         /* Retrieve the saved copy and we're done. */
 951         memcpy((void*)p, tmp, INADDRSZ);
 952 }
 953
 954 static void
 955 map_v4v6_hostent(hp, bpp, lenp)
 956         struct hostent *hp;
 957         char **bpp;
 958         int *lenp;
 959 {
 960         char **ap;
 961
 962         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 963                 return;
 964         hp->h_addrtype = AF_INET6;
 965         hp->h_length = IN6ADDRSZ;
 966         for (ap = hp->h_addr_list; *ap; ap++) {
 967                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 968
 969                 if (*lenp < (i + IN6ADDRSZ)) {
 970                         /* Out of memory.  Truncate address list here.  XXX */
 971                         *ap = NULL;
 972                         return;
 973                 }
 974                 *bpp += i;
 975                 *lenp -= i;
 976                 map_v4v6_address(*ap, *bpp);
 977                 *ap = *bpp;
 978                 *bpp += IN6ADDRSZ;
 979                 *lenp -= IN6ADDRSZ;
 980         }
 981 }
 982
 983 #ifdef RESOLVSORT
 984 extern void
 985 addrsort(ap, num)
 986         char **ap;
 987         int num;
 988 {
 989         int i, j;
 990         char **p;
 991         short aval[MAXADDRS];
 992         int needsort = 0;
 993
 994         p = ap;
 995         for (i = 0; i < num; i++, p++) {
 996             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 997                 if (_res.sort_list[j].addr.s_addr ==
 998                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 999                         break;
1000             aval[i] = j;
1001             if (needsort == 0 && i > 0 && j < aval[i-1])
1002                 needsort = i;
1003         }
1004         if (!needsort)
1005             return;
1006
1007         while (needsort < num) {
1008             for (j = needsort - 1; j >= 0; j--) {
1009                 if (aval[j] > aval[j+1]) {
1010                     char *hp;
1011
1012                     i = aval[j];
1013                     aval[j] = aval[j+1];
1014                     aval[j+1] = i;
1015
1016                     hp = ap[j];
1017                     ap[j] = ap[j+1];
1018                     ap[j+1] = hp;
1019
1020                 } else
1021                     break;
1022             }
1023             needsort++;
1024         }
1025 }
1026 #endif
1027
1028 #if defined(BSD43_BSD43_NFS) || defined(sun)
1029 /* some libc's out there are bound internally to these names (UMIPS) */
1030 void
1031 ht_sethostent(stayopen)
1032         int stayopen;
1033 {
1034         _sethtent(stayopen);
1035 }
1036
1037 void
1038 ht_endhostent()
1039 {
1040         _endhtent();
1041 }
1042
1043 struct hostent *
1044 ht_gethostbyname(name)
1045         char *name;
1046 {
1047         return (_gethtbyname(name));
1048 }
1049
1050 struct hostent *
1051 ht_gethostbyaddr(addr, len, af)
1052         const char *addr;
1053         size_t len;
1054         int af;
1055 {
1056         return (_gethtbyaddr(addr, len, af));
1057 }
1058
1059 struct hostent *
1060 gethostent()
1061 {
1062         return (_gethtent());
1063 }
1064
1065 void
1066 dns_service()
1067 {
1068         return;
1069 }
1070
1071 #undef dn_skipname
1072 dn_skipname(comp_dn, eom)
1073         const u_char *comp_dn, *eom;
1074 {
1075         return (__dn_skipname(comp_dn, eom));
1076 }
1077 #endif /*old-style libc with yp junk in it*/