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  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  * -
  35  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  36  *
  37  * Permission to use, copy, modify, and distribute this software for any
  38  * purpose with or without fee is hereby granted, provided that the above
  39  * copyright notice and this permission notice appear in all copies, and that
  40  * the name of Digital Equipment Corporation not be used in advertising or
  41  * publicity pertaining to distribution of the document or software without
  42  * specific, written prior permission.
  43  *
  44  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  45  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  46  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  47  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  48  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  49  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  50  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  51  * SOFTWARE.
  52  * -
  53  * --Copyright--
  54  */
  55
  56 #if defined(LIBC_SCCS) && !defined(lint)
  57 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
  58 static char rcsid[] = "$Id$";
  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 #ifndef LOG_AUTH
  76 # define LOG_AUTH 0
  77 #endif
  78
  79 #define MULTI_PTRS_ARE_ALIASES 1        /* XXX - experimental */
  80
  81 #if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
  82 # include <stdlib.h>
  83 # include <string.h>
  84 #else
  85 # include "../conf/portability.h"
  86 #endif
  87
  88 #if defined(USE_OPTIONS_H)
  89 # include <../conf/options.h>
  90 #endif
  91
  92 #ifdef SPRINTF_CHAR
  93 # define SPRINTF(x) strlen(sprintf/**/x)
  94 #else
  95 # define SPRINTF(x) ((size_t)sprintf x)
  96 #endif
  97
  98 #define MAXALIASES      35
  99 #define MAXADDRS        35
 100
 101 static const char AskedForGot[] =
 102                           "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
 103
 104 static char *h_addr_ptrs[MAXADDRS + 1];
 105
 106 static struct hostent host;
 107 static char *host_aliases[MAXALIASES];
 108 static char hostbuf[8*1024];
 109 static u_char host_addr[16];    /* IPv4 or IPv6 */
 110 static FILE *hostf = NULL;
 111 static int stayopen = 0;
 112
 113 static void map_v4v6_address __P((const char *src, char *dst));
 114 static void map_v4v6_hostent __P((struct hostent *hp, char **bp, int *len));
 115
 116 #ifdef RESOLVSORT
 117 static void addrsort __P((char **, int));
 118 #endif
 119
 120 #if PACKETSZ > 1024
 121 #define MAXPACKET       PACKETSZ
 122 #else
 123 #define MAXPACKET       1024
 124 #endif
 125
 126 typedef union {
 127     HEADER hdr;
 128     u_char buf[MAXPACKET];
 129 } querybuf;
 130
 131 typedef union {
 132     int32_t al;
 133     char ac;
 134 } align;
 135
 136 extern int h_errno;
 137
 138 #ifdef DEBUG
 139 static void
 140 dprintf(msg, num)
 141         char *msg;
 142         int num;
 143 {
 144         if (_res.options & RES_DEBUG) {
 145                 int save = errno;
 146
 147                 printf(msg, num);
 148                 __set_errno (save);
 149         }
 150 }
 151 #else
 152 # define dprintf(msg, num) /*nada*/
 153 #endif
 154
 155 static struct hostent *
 156 getanswer(answer, anslen, qname, qtype)
 157         const querybuf *answer;
 158         int anslen;
 159         const char *qname;
 160         int qtype;
 161 {
 162         register const HEADER *hp;
 163         register const u_char *cp;
 164         register int n;
 165         const u_char *eom;
 166         char *bp, **ap, **hap;
 167         int type, class, buflen, ancount, qdcount;
 168         int haveanswer, had_error;
 169         int toobig = 0;
 170         char tbuf[MAXDNAME];
 171         const char *tname;
 172         int (*name_ok) __P((const char *));
 173
 174         tname = qname;
 175         host.h_name = NULL;
 176         eom = answer->buf + anslen;
 177         switch (qtype) {
 178         case T_A:
 179         case T_AAAA:
 180                 name_ok = res_hnok;
 181                 break;
 182         case T_PTR:
 183                 name_ok = res_dnok;
 184                 break;
 185         default:
 186                 return (NULL);  /* XXX should be abort(); */
 187         }
 188         /*
 189          * find first satisfactory answer
 190          */
 191         hp = &answer->hdr;
 192         ancount = ntohs(hp->ancount);
 193         qdcount = ntohs(hp->qdcount);
 194         bp = hostbuf;
 195         buflen = sizeof hostbuf;
 196         cp = answer->buf + HFIXEDSZ;
 197         if (qdcount != 1) {
 198                 __set_h_errno (NO_RECOVERY);
 199                 return (NULL);
 200         }
 201         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 202         if ((n < 0) || !(*name_ok)(bp)) {
 203                 __set_h_errno (NO_RECOVERY);
 204                 return (NULL);
 205         }
 206         cp += n + QFIXEDSZ;
 207         if (qtype == T_A || qtype == T_AAAA) {
 208                 /* res_send() has already verified that the query name is the
 209                  * same as the one we sent; this just gets the expanded name
 210                  * (i.e., with the succeeding search-domain tacked on).
 211                  */
 212                 n = strlen(bp) + 1;             /* for the \0 */
 213                 host.h_name = bp;
 214                 bp += n;
 215                 buflen -= n;
 216                 /* The qname can be abbreviated, but h_name is now absolute. */
 217                 qname = host.h_name;
 218         }
 219         ap = host_aliases;
 220         *ap = NULL;
 221         host.h_aliases = host_aliases;
 222         hap = h_addr_ptrs;
 223         *hap = NULL;
 224         host.h_addr_list = h_addr_ptrs;
 225         haveanswer = 0;
 226         had_error = 0;
 227         while (ancount-- > 0 && cp < eom && !had_error) {
 228                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 229                 if ((n < 0) || !(*name_ok)(bp)) {
 230                         had_error++;
 231                         continue;
 232                 }
 233                 cp += n;                        /* name */
 234                 type = _getshort(cp);
 235                 cp += INT16SZ;                  /* type */
 236                 class = _getshort(cp);
 237                 cp += INT16SZ + INT32SZ;        /* class, TTL */
 238                 n = _getshort(cp);
 239                 cp += INT16SZ;                  /* len */
 240                 if (class != C_IN) {
 241                         /* XXX - debug? syslog? */
 242                         cp += n;
 243                         continue;               /* XXX - had_error++ ? */
 244                 }
 245                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 246                         if (ap >= &host_aliases[MAXALIASES-1])
 247                                 continue;
 248                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 249                         if ((n < 0) || !(*name_ok)(tbuf)) {
 250                                 had_error++;
 251                                 continue;
 252                         }
 253                         cp += n;
 254                         /* Store alias. */
 255                         *ap++ = bp;
 256                         n = strlen(bp) + 1;     /* for the \0 */
 257                         bp += n;
 258                         buflen -= n;
 259                         /* Get canonical name. */
 260                         n = strlen(tbuf) + 1;   /* for the \0 */
 261                         if (n > buflen) {
 262                                 had_error++;
 263                                 continue;
 264                         }
 265                         strcpy(bp, tbuf);
 266                         host.h_name = bp;
 267                         bp += n;
 268                         buflen -= n;
 269                         continue;
 270                 }
 271                 if (qtype == T_PTR && type == T_CNAME) {
 272                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 273                         if ((n < 0) || !res_hnok(tbuf)) {
 274                                 had_error++;
 275                                 continue;
 276                         }
 277                         cp += n;
 278                         /* Get canonical name. */
 279                         n = strlen(tbuf) + 1;   /* for the \0 */
 280                         if (n > buflen) {
 281                                 had_error++;
 282                                 continue;
 283                         }
 284                         strcpy(bp, tbuf);
 285                         tname = bp;
 286                         bp += n;
 287                         buflen -= n;
 288                         continue;
 289                 }
 290                 if (type != qtype) {
 291                         syslog(LOG_NOTICE|LOG_AUTH,
 292                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 293                                qname, p_class(C_IN), p_type(qtype),
 294                                p_type(type));
 295                         cp += n;
 296                         continue;               /* XXX - had_error++ ? */
 297                 }
 298                 switch (type) {
 299                 case T_PTR:
 300                         if (strcasecmp(tname, bp) != 0) {
 301                                 syslog(LOG_NOTICE|LOG_AUTH,
 302                                        AskedForGot, qname, bp);
 303                                 cp += n;
 304                                 continue;       /* XXX - had_error++ ? */
 305                         }
 306                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 307                         if ((n < 0) || !res_hnok(bp)) {
 308                                 had_error++;
 309                                 break;
 310                         }
 311 #if MULTI_PTRS_ARE_ALIASES
 312                         cp += n;
 313                         if (!haveanswer)
 314                                 host.h_name = bp;
 315                         else if (ap < &host_aliases[MAXALIASES-1])
 316                                 *ap++ = bp;
 317                         else
 318                                 n = -1;
 319                         if (n != -1) {
 320                                 n = strlen(bp) + 1;     /* for the \0 */
 321                                 bp += n;
 322                                 buflen -= n;
 323                         }
 324                         break;
 325 #else
 326                         host.h_name = bp;
 327                         if (_res.options & RES_USE_INET6) {
 328                                 n = strlen(bp) + 1;     /* for the \0 */
 329                                 bp += n;
 330                                 buflen -= n;
 331                                 map_v4v6_hostent(&host, &bp, &buflen);
 332                         }
 333                         __set_h_errno (NETDB_SUCCESS);
 334                         return (&host);
 335 #endif
 336                 case T_A:
 337                 case T_AAAA:
 338                         if (strcasecmp(host.h_name, bp) != 0) {
 339                                 syslog(LOG_NOTICE|LOG_AUTH,
 340                                        AskedForGot, host.h_name, bp);
 341                                 cp += n;
 342                                 continue;       /* XXX - had_error++ ? */
 343                         }
 344                         if (n != host.h_length) {
 345                                 cp += n;
 346                                 continue;
 347                         }
 348                         if (!haveanswer) {
 349                                 register int nn;
 350
 351                                 host.h_name = bp;
 352                                 nn = strlen(bp) + 1;    /* for the \0 */
 353                                 bp += nn;
 354                                 buflen -= nn;
 355                         }
 356
 357                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 358
 359                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 360                                 dprintf("size (%d) too big\n", n);
 361                                 had_error++;
 362                                 continue;
 363                         }
 364                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 365                                 if (!toobig++)
 366                                         dprintf("Too many addresses (%d)\n",
 367                                                 MAXADDRS);
 368                                 cp += n;
 369                                 continue;
 370                         }
 371                         bcopy(cp, *hap++ = bp, n);
 372                         bp += n;
 373                         buflen -= n;
 374                         cp += n;
 375                         break;
 376                 default:
 377                         abort();
 378                 }
 379                 if (!had_error)
 380                         haveanswer++;
 381         }
 382         if (haveanswer) {
 383                 *ap = NULL;
 384                 *hap = NULL;
 385 # if defined(RESOLVSORT)
 386                 /*
 387                  * Note: we sort even if host can take only one address
 388                  * in its return structures - should give it the "best"
 389                  * address in that case, not some random one
 390                  */
 391                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 392                         addrsort(h_addr_ptrs, haveanswer);
 393 # endif /*RESOLVSORT*/
 394                 if (!host.h_name) {
 395                         n = strlen(qname) + 1;  /* for the \0 */
 396                         if (n > buflen)
 397                                 goto try_again;
 398                         strcpy(bp, qname);
 399                         host.h_name = bp;
 400                         bp += n;
 401                         buflen -= n;
 402                 }
 403                 if (_res.options & RES_USE_INET6)
 404                         map_v4v6_hostent(&host, &bp, &buflen);
 405                 __set_h_errno (NETDB_SUCCESS);
 406                 return (&host);
 407         }
 408  try_again:
 409         __set_h_errno (TRY_AGAIN);
 410         return (NULL);
 411 }
 412
 413 struct hostent *
 414 gethostbyname(name)
 415         const char *name;
 416 {
 417         struct hostent *hp;
 418
 419         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 420                 __set_h_errno (NETDB_INTERNAL);
 421                 return (NULL);
 422        }
 423         if (_res.options & RES_USE_INET6) {
 424                 hp = gethostbyname2(name, AF_INET6);
 425                 if (hp)
 426                         return (hp);
 427         }
 428         return (gethostbyname2(name, AF_INET));
 429 }
 430
 431 struct hostent *
 432 gethostbyname2(name, af)
 433         const char *name;
 434         int af;
 435 {
 436         querybuf buf;
 437         register const char *cp;
 438         char *bp;
 439         int n, size, type, len;
 440         extern struct hostent *_gethtbyname2();
 441
 442         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 443                 __set_h_errno (NETDB_INTERNAL);
 444                 return (NULL);
 445         }
 446
 447         switch (af) {
 448         case AF_INET:
 449                 size = INADDRSZ;
 450                 type = T_A;
 451                 break;
 452         case AF_INET6:
 453                 size = IN6ADDRSZ;
 454                 type = T_AAAA;
 455                 break;
 456         default:
 457                 __set_h_errno (NETDB_INTERNAL);
 458                 __set_errno (EAFNOSUPPORT);
 459                 return (NULL);
 460         }
 461
 462         host.h_addrtype = af;
 463         host.h_length = size;
 464
 465         /*
 466          * if there aren't any dots, it could be a user-level alias.
 467          * this is also done in res_query() since we are not the only
 468          * function that looks up host names.
 469          */
 470         if (!strchr(name, '.') && (cp = __hostalias(name)))
 471                 name = cp;
 472
 473         /*
 474          * disallow names consisting only of digits/dots, unless
 475          * they end in a dot.
 476          */
 477         if (isdigit(name[0]))
 478                 for (cp = name;; ++cp) {
 479                         if (!*cp) {
 480                                 if (*--cp == '.')
 481                                         break;
 482                                 /*
 483                                  * All-numeric, no dot at the end.
 484                                  * Fake up a hostent as if we'd actually
 485                                  * done a lookup.
 486                                  */
 487                                 if (inet_pton(af, name, host_addr) <= 0) {
 488                                         __set_h_errno (HOST_NOT_FOUND);
 489                                         return (NULL);
 490                                 }
 491                                 strncpy(hostbuf, name, MAXDNAME);
 492                                 hostbuf[MAXDNAME] = '\0';
 493                                 bp = hostbuf + MAXDNAME;
 494                                 len = sizeof hostbuf - MAXDNAME;
 495                                 host.h_name = hostbuf;
 496                                 host.h_aliases = host_aliases;
 497                                 host_aliases[0] = NULL;
 498                                 h_addr_ptrs[0] = (char *)host_addr;
 499                                 h_addr_ptrs[1] = NULL;
 500                                 host.h_addr_list = h_addr_ptrs;
 501                                 if (_res.options & RES_USE_INET6)
 502                                         map_v4v6_hostent(&host, &bp, &len);
 503                                 __set_h_errno (NETDB_SUCCESS);
 504                                 return (&host);
 505                         }
 506                         if (!isdigit(*cp) && *cp != '.')
 507                                 break;
 508                }
 509         if (isxdigit(name[0]) || name[0] == ':')
 510                 for (cp = name;; ++cp) {
 511                         if (!*cp) {
 512                                 if (*--cp == '.')
 513                                         break;
 514                                 /*
 515                                  * All-IPv6-legal, no dot at the end.
 516                                  * Fake up a hostent as if we'd actually
 517                                  * done a lookup.
 518                                  */
 519                                 if (inet_pton(af, name, host_addr) <= 0) {
 520                                         __set_h_errno (HOST_NOT_FOUND);
 521                                         return (NULL);
 522                                 }
 523                                 strncpy(hostbuf, name, MAXDNAME);
 524                                 hostbuf[MAXDNAME] = '\0';
 525                                 bp = hostbuf + MAXDNAME;
 526                                 len = sizeof hostbuf - MAXDNAME;
 527                                 host.h_name = hostbuf;
 528                                 host.h_aliases = host_aliases;
 529                                 host_aliases[0] = NULL;
 530                                 h_addr_ptrs[0] = (char *)host_addr;
 531                                 h_addr_ptrs[1] = NULL;
 532                                 host.h_addr_list = h_addr_ptrs;
 533                                 __set_h_errno (NETDB_SUCCESS);
 534                                 return (&host);
 535                         }
 536                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
 537                                 break;
 538                 }
 539
 540         if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) {
 541                 dprintf("res_search failed (%d)\n", n);
 542                 if (errno == ECONNREFUSED)
 543                         return (_gethtbyname2(name, af));
 544                 return (NULL);
 545         }
 546         return (getanswer(&buf, n, name, type));
 547 }
 548
 549 struct hostent *
 550 gethostbyaddr(addr, len, af)
 551         const char *addr;       /* XXX should have been def'd as u_char! */
 552         int len, af;
 553 {
 554         const u_char *uaddr = (const u_char *)addr;
 555         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 556         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 557         int n, size;
 558         querybuf buf;
 559         register struct hostent *hp;
 560         char qbuf[MAXDNAME+1], *qp;
 561 #ifdef SUNSECURITY
 562         register struct hostent *rhp;
 563         char **haddr;
 564         u_long old_options;
 565         char hname2[MAXDNAME+1];
 566 #endif /*SUNSECURITY*/
 567         extern struct hostent *_gethtbyaddr();
 568
 569         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 570                 __set_h_errno (NETDB_INTERNAL);
 571                 return (NULL);
 572         }
 573         if (af == AF_INET6 && len == IN6ADDRSZ &&
 574             (!bcmp(uaddr, mapped, sizeof mapped) ||
 575              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 576                 /* Unmap. */
 577                 addr += sizeof mapped;
 578                 uaddr += sizeof mapped;
 579                 af = AF_INET;
 580                 len = INADDRSZ;
 581         }
 582         switch (af) {
 583         case AF_INET:
 584                 size = INADDRSZ;
 585                 break;
 586         case AF_INET6:
 587                 size = IN6ADDRSZ;
 588                 break;
 589         default:
 590                 __set_errno (EAFNOSUPPORT);
 591                 __set_h_errno (NETDB_INTERNAL);
 592                 return (NULL);
 593         }
 594         if (size != len) {
 595                 __set_errno (EINVAL);
 596                 __set_h_errno (NETDB_INTERNAL);
 597                 return (NULL);
 598         }
 599         switch (af) {
 600         case AF_INET:
 601                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 602                                (uaddr[3] & 0xff),
 603                                (uaddr[2] & 0xff),
 604                                (uaddr[1] & 0xff),
 605                                (uaddr[0] & 0xff));
 606                 break;
 607         case AF_INET6:
 608                 qp = qbuf;
 609                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 610                         qp += SPRINTF((qp, "%x.%x.",
 611                                        uaddr[n] & 0xf,
 612                                        (uaddr[n] >> 4) & 0xf));
 613                 }
 614                 strcpy(qp, "ip6.int");
 615                 break;
 616         default:
 617                 abort();
 618         }
 619         n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
 620         if (n < 0) {
 621                 dprintf("res_query failed (%d)\n", n);
 622                 if (errno == ECONNREFUSED)
 623                         return (_gethtbyaddr(addr, len, af));
 624                 return (NULL);
 625         }
 626         if (!(hp = getanswer(&buf, n, qbuf, T_PTR)))
 627                 return (NULL);  /* h_errno was set by getanswer() */
 628 #ifdef SUNSECURITY
 629         if (af == AF_INET) {
 630             /*
 631              * turn off search as the name should be absolute,
 632              * 'localhost' should be matched by defnames
 633              */
 634             strncpy(hname2, hp->h_name, MAXDNAME);
 635             hname2[MAXDNAME] = '\0';
 636             old_options = _res.options;
 637             _res.options &= ~RES_DNSRCH;
 638             _res.options |= RES_DEFNAMES;
 639             if (!(rhp = gethostbyname(hname2))) {
 640                 syslog(LOG_NOTICE|LOG_AUTH,
 641                        "gethostbyaddr: No A record for %s (verifying [%s])",
 642                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 643                 _res.options = old_options;
 644                 __set_h_errno (HOST_NOT_FOUND);
 645                 return (NULL);
 646             }
 647             _res.options = old_options;
 648             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 649                 if (!memcmp(*haddr, addr, INADDRSZ))
 650                         break;
 651             if (!*haddr) {
 652                 syslog(LOG_NOTICE|LOG_AUTH,
 653                        "gethostbyaddr: A record of %s != PTR record [%s]",
 654                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 655                 __set_h_errno (HOST_NOT_FOUND);
 656                 return (NULL);
 657             }
 658         }
 659 #endif /*SUNSECURITY*/
 660         hp->h_addrtype = af;
 661         hp->h_length = len;
 662         bcopy(addr, host_addr, len);
 663         h_addr_ptrs[0] = (char *)host_addr;
 664         h_addr_ptrs[1] = NULL;
 665         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 666                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 667                 hp->h_addrtype = AF_INET6;
 668                 hp->h_length = IN6ADDRSZ;
 669         }
 670         __set_h_errno (NETDB_SUCCESS);
 671         return (hp);
 672 }
 673
 674 void
 675 _sethtent(f)
 676         int f;
 677 {
 678         if (!hostf)
 679                 hostf = fopen(_PATH_HOSTS, "r" );
 680         else
 681                 rewind(hostf);
 682         stayopen = f;
 683 }
 684
 685 void
 686 _endhtent()
 687 {
 688         if (hostf && !stayopen) {
 689                 (void) fclose(hostf);
 690                 hostf = NULL;
 691         }
 692 }
 693
 694 struct hostent *
 695 _gethtent()
 696 {
 697         char *p;
 698         register char *cp, **q;
 699         int af, len;
 700
 701         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
 702                 __set_h_errno (NETDB_INTERNAL);
 703                 return (NULL);
 704         }
 705  again:
 706         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 707                 __set_h_errno (HOST_NOT_FOUND);
 708                 return (NULL);
 709         }
 710         if (*p == '#')
 711                 goto again;
 712         if (!(cp = strpbrk(p, "#\n")))
 713                 goto again;
 714         *cp = '\0';
 715         if (!(cp = strpbrk(p, " \t")))
 716                 goto again;
 717         *cp++ = '\0';
 718         if ((_res.options & RES_USE_INET6) &&
 719             inet_pton(AF_INET6, p, host_addr) > 0) {
 720                 af = AF_INET6;
 721                 len = IN6ADDRSZ;
 722         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 723                 if (_res.options & RES_USE_INET6) {
 724                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 725                         af = AF_INET6;
 726                         len = IN6ADDRSZ;
 727                 } else {
 728                         af = AF_INET;
 729                         len = INADDRSZ;
 730                 }
 731         } else {
 732                 goto again;
 733         }
 734         h_addr_ptrs[0] = (char *)host_addr;
 735         h_addr_ptrs[1] = NULL;
 736         host.h_addr_list = h_addr_ptrs;
 737         host.h_length = len;
 738         host.h_addrtype = af;
 739         while (*cp == ' ' || *cp == '\t')
 740                 cp++;
 741         host.h_name = cp;
 742         q = host.h_aliases = host_aliases;
 743         if (cp = strpbrk(cp, " \t"))
 744                 *cp++ = '\0';
 745         while (cp && *cp) {
 746                 if (*cp == ' ' || *cp == '\t') {
 747                         cp++;
 748                         continue;
 749                 }
 750                 if (q < &host_aliases[MAXALIASES - 1])
 751                         *q++ = cp;
 752                 if (cp = strpbrk(cp, " \t"))
 753                         *cp++ = '\0';
 754         }
 755         *q = NULL;
 756         if (_res.options & RES_USE_INET6) {
 757                 char *bp = hostbuf;
 758                 int buflen = sizeof hostbuf;
 759
 760                 map_v4v6_hostent(&host, &bp, &buflen);
 761         }
 762         __set_h_errno (NETDB_SUCCESS);
 763         return (&host);
 764 }
 765
 766 struct hostent *
 767 _gethtbyname(name)
 768         const char *name;
 769 {
 770         extern struct hostent *_gethtbyname2();
 771         struct hostent *hp;
 772
 773         if (_res.options & RES_USE_INET6) {
 774                 hp = _gethtbyname2(name, AF_INET6);
 775                 if (hp)
 776                         return (hp);
 777         }
 778         return (_gethtbyname2(name, AF_INET));
 779 }
 780
 781 struct hostent *
 782 _gethtbyname2(name, af)
 783         const char *name;
 784         int af;
 785 {
 786         register struct hostent *p;
 787         register char **cp;
 788
 789         _sethtent(0);
 790         while (p = _gethtent()) {
 791                 if (p->h_addrtype != af)
 792                         continue;
 793                 if (strcasecmp(p->h_name, name) == 0)
 794                         break;
 795                 for (cp = p->h_aliases; *cp != 0; cp++)
 796                         if (strcasecmp(*cp, name) == 0)
 797                                 goto found;
 798         }
 799  found:
 800         _endhtent();
 801         return (p);
 802 }
 803
 804 struct hostent *
 805 _gethtbyaddr(addr, len, af)
 806         const char *addr;
 807         int len, af;
 808 {
 809         register struct hostent *p;
 810
 811         _sethtent(0);
 812         while (p = _gethtent())
 813                 if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
 814                         break;
 815         _endhtent();
 816         return (p);
 817 }
 818
 819 static void
 820 map_v4v6_address(src, dst)
 821         const char *src;
 822         char *dst;
 823 {
 824         u_char *p = (u_char *)dst;
 825         char tmp[INADDRSZ];
 826         int i;
 827
 828         /* Stash a temporary copy so our caller can update in place. */
 829         bcopy(src, tmp, INADDRSZ);
 830         /* Mark this ipv6 addr as a mapped ipv4. */
 831         for (i = 0; i < 10; i++)
 832                 *p++ = 0x00;
 833         *p++ = 0xff;
 834         *p++ = 0xff;
 835         /* Retrieve the saved copy and we're done. */
 836         bcopy(tmp, (void*)p, INADDRSZ);
 837 }
 838
 839 static void
 840 map_v4v6_hostent(hp, bpp, lenp)
 841         struct hostent *hp;
 842         char **bpp;
 843         int *lenp;
 844 {
 845         char **ap;
 846
 847         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 848                 return;
 849         hp->h_addrtype = AF_INET6;
 850         hp->h_length = IN6ADDRSZ;
 851         for (ap = hp->h_addr_list; *ap; ap++) {
 852                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 853
 854                 if (*lenp < (i + IN6ADDRSZ)) {
 855                         /* Out of memory.  Truncate address list here.  XXX */
 856                         *ap = NULL;
 857                         return;
 858                 }
 859                 *bpp += i;
 860                 *lenp -= i;
 861                 map_v4v6_address(*ap, *bpp);
 862                 *ap = *bpp;
 863                 *bpp += IN6ADDRSZ;
 864                 *lenp -= IN6ADDRSZ;
 865         }
 866 }
 867
 868 #ifdef RESOLVSORT
 869 static void
 870 addrsort(ap, num)
 871         char **ap;
 872         int num;
 873 {
 874         int i, j;
 875         char **p;
 876         short aval[MAXADDRS];
 877         int needsort = 0;
 878
 879         p = ap;
 880         for (i = 0; i < num; i++, p++) {
 881             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 882                 if (_res.sort_list[j].addr.s_addr ==
 883                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 884                         break;
 885             aval[i] = j;
 886             if (needsort == 0 && i > 0 && j < aval[i-1])
 887                 needsort = i;
 888         }
 889         if (!needsort)
 890             return;
 891
 892         while (needsort < num) {
 893             for (j = needsort - 1; j >= 0; j--) {
 894                 if (aval[j] > aval[j+1]) {
 895                     char *hp;
 896
 897                     i = aval[j];
 898                     aval[j] = aval[j+1];
 899                     aval[j+1] = i;
 900
 901                     hp = ap[j];
 902                     ap[j] = ap[j+1];
 903                     ap[j+1] = hp;
 904
 905                 } else
 906                     break;
 907             }
 908             needsort++;
 909         }
 910 }
 911 #endif
 912
 913 #if defined(BSD43_BSD43_NFS) || defined(sun)
 914 /* some libc's out there are bound internally to these names (UMIPS) */
 915 void
 916 ht_sethostent(stayopen)
 917         int stayopen;
 918 {
 919         _sethtent(stayopen);
 920 }
 921
 922 void
 923 ht_endhostent()
 924 {
 925         _endhtent();
 926 }
 927
 928 struct hostent *
 929 ht_gethostbyname(name)
 930         char *name;
 931 {
 932         return (_gethtbyname(name));
 933 }
 934
 935 struct hostent *
 936 ht_gethostbyaddr(addr, len, af)
 937         const char *addr;
 938         int len, af;
 939 {
 940         return (_gethtbyaddr(addr, len, af));
 941 }
 942
 943 struct hostent *
 944 gethostent()
 945 {
 946         return (_gethtent());
 947 }
 948
 949 void
 950 dns_service()
 951 {
 952         return;
 953 }
 954
 955 #undef dn_skipname
 956 dn_skipname(comp_dn, eom)
 957         const u_char *comp_dn, *eom;
 958 {
 959         return (__dn_skipname(comp_dn, eom));
 960 }
 961 #endif /*old-style libc with yp junk in it*/