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 #ifndef h_errno
 137 extern int h_errno;
 138 #endif
 139
 140 #ifdef DEBUG
 141 static void
 142 dprintf(msg, num)
 143         char *msg;
 144         int num;
 145 {
 146         if (_res.options & RES_DEBUG) {
 147                 int save = errno;
 148
 149                 printf(msg, num);
 150                 __set_errno (save);
 151         }
 152 }
 153 #else
 154 # define dprintf(msg, num) /*nada*/
 155 #endif
 156
 157 static struct hostent *
 158 getanswer(answer, anslen, qname, qtype)
 159         const querybuf *answer;
 160         int anslen;
 161         const char *qname;
 162         int qtype;
 163 {
 164         register const HEADER *hp;
 165         register const u_char *cp;
 166         register int n;
 167         const u_char *eom;
 168         char *bp, **ap, **hap;
 169         int type, class, buflen, ancount, qdcount;
 170         int haveanswer, had_error;
 171         int toobig = 0;
 172         char tbuf[MAXDNAME];
 173         const char *tname;
 174         int (*name_ok) __P((const char *));
 175
 176         tname = qname;
 177         host.h_name = NULL;
 178         eom = answer->buf + anslen;
 179         switch (qtype) {
 180         case T_A:
 181         case T_AAAA:
 182                 name_ok = res_hnok;
 183                 break;
 184         case T_PTR:
 185                 name_ok = res_dnok;
 186                 break;
 187         default:
 188                 return (NULL);  /* XXX should be abort(); */
 189         }
 190         /*
 191          * find first satisfactory answer
 192          */
 193         hp = &answer->hdr;
 194         ancount = ntohs(hp->ancount);
 195         qdcount = ntohs(hp->qdcount);
 196         bp = hostbuf;
 197         buflen = sizeof hostbuf;
 198         cp = answer->buf + HFIXEDSZ;
 199         if (qdcount != 1) {
 200                 __set_h_errno (NO_RECOVERY);
 201                 return (NULL);
 202         }
 203         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 204         if ((n < 0) || !(*name_ok)(bp)) {
 205                 __set_h_errno (NO_RECOVERY);
 206                 return (NULL);
 207         }
 208         cp += n + QFIXEDSZ;
 209         if (qtype == T_A || qtype == T_AAAA) {
 210                 /* res_send() has already verified that the query name is the
 211                  * same as the one we sent; this just gets the expanded name
 212                  * (i.e., with the succeeding search-domain tacked on).
 213                  */
 214                 n = strlen(bp) + 1;             /* for the \0 */
 215                 host.h_name = bp;
 216                 bp += n;
 217                 buflen -= n;
 218                 /* The qname can be abbreviated, but h_name is now absolute. */
 219                 qname = host.h_name;
 220         }
 221         ap = host_aliases;
 222         *ap = NULL;
 223         host.h_aliases = host_aliases;
 224         hap = h_addr_ptrs;
 225         *hap = NULL;
 226         host.h_addr_list = h_addr_ptrs;
 227         haveanswer = 0;
 228         had_error = 0;
 229         while (ancount-- > 0 && cp < eom && !had_error) {
 230                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 231                 if ((n < 0) || !(*name_ok)(bp)) {
 232                         had_error++;
 233                         continue;
 234                 }
 235                 cp += n;                        /* name */
 236                 type = _getshort(cp);
 237                 cp += INT16SZ;                  /* type */
 238                 class = _getshort(cp);
 239                 cp += INT16SZ + INT32SZ;        /* class, TTL */
 240                 n = _getshort(cp);
 241                 cp += INT16SZ;                  /* len */
 242                 if (class != C_IN) {
 243                         /* XXX - debug? syslog? */
 244                         cp += n;
 245                         continue;               /* XXX - had_error++ ? */
 246                 }
 247                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 248                         if (ap >= &host_aliases[MAXALIASES-1])
 249                                 continue;
 250                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 251                         if ((n < 0) || !(*name_ok)(tbuf)) {
 252                                 had_error++;
 253                                 continue;
 254                         }
 255                         cp += n;
 256                         /* Store alias. */
 257                         *ap++ = bp;
 258                         n = strlen(bp) + 1;     /* for the \0 */
 259                         bp += n;
 260                         buflen -= n;
 261                         /* Get canonical name. */
 262                         n = strlen(tbuf) + 1;   /* for the \0 */
 263                         if (n > buflen) {
 264                                 had_error++;
 265                                 continue;
 266                         }
 267                         strcpy(bp, tbuf);
 268                         host.h_name = bp;
 269                         bp += n;
 270                         buflen -= n;
 271                         continue;
 272                 }
 273                 if (qtype == T_PTR && type == T_CNAME) {
 274                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 275                         if ((n < 0) || !res_hnok(tbuf)) {
 276                                 had_error++;
 277                                 continue;
 278                         }
 279                         cp += n;
 280                         /* Get canonical name. */
 281                         n = strlen(tbuf) + 1;   /* for the \0 */
 282                         if (n > buflen) {
 283                                 had_error++;
 284                                 continue;
 285                         }
 286                         strcpy(bp, tbuf);
 287                         tname = bp;
 288                         bp += n;
 289                         buflen -= n;
 290                         continue;
 291                 }
 292                 if (type != qtype) {
 293                         syslog(LOG_NOTICE|LOG_AUTH,
 294                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 295                                qname, p_class(C_IN), p_type(qtype),
 296                                p_type(type));
 297                         cp += n;
 298                         continue;               /* XXX - had_error++ ? */
 299                 }
 300                 switch (type) {
 301                 case T_PTR:
 302                         if (strcasecmp(tname, bp) != 0) {
 303                                 syslog(LOG_NOTICE|LOG_AUTH,
 304                                        AskedForGot, qname, bp);
 305                                 cp += n;
 306                                 continue;       /* XXX - had_error++ ? */
 307                         }
 308                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 309                         if ((n < 0) || !res_hnok(bp)) {
 310                                 had_error++;
 311                                 break;
 312                         }
 313 #if MULTI_PTRS_ARE_ALIASES
 314                         cp += n;
 315                         if (!haveanswer)
 316                                 host.h_name = bp;
 317                         else if (ap < &host_aliases[MAXALIASES-1])
 318                                 *ap++ = bp;
 319                         else
 320                                 n = -1;
 321                         if (n != -1) {
 322                                 n = strlen(bp) + 1;     /* for the \0 */
 323                                 bp += n;
 324                                 buflen -= n;
 325                         }
 326                         break;
 327 #else
 328                         host.h_name = bp;
 329                         if (_res.options & RES_USE_INET6) {
 330                                 n = strlen(bp) + 1;     /* for the \0 */
 331                                 bp += n;
 332                                 buflen -= n;
 333                                 map_v4v6_hostent(&host, &bp, &buflen);
 334                         }
 335                         __set_h_errno (NETDB_SUCCESS);
 336                         return (&host);
 337 #endif
 338                 case T_A:
 339                 case T_AAAA:
 340                         if (strcasecmp(host.h_name, bp) != 0) {
 341                                 syslog(LOG_NOTICE|LOG_AUTH,
 342                                        AskedForGot, host.h_name, bp);
 343                                 cp += n;
 344                                 continue;       /* XXX - had_error++ ? */
 345                         }
 346                         if (n != host.h_length) {
 347                                 cp += n;
 348                                 continue;
 349                         }
 350                         if (!haveanswer) {
 351                                 register int nn;
 352
 353                                 host.h_name = bp;
 354                                 nn = strlen(bp) + 1;    /* for the \0 */
 355                                 bp += nn;
 356                                 buflen -= nn;
 357                         }
 358
 359                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 360
 361                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 362                                 dprintf("size (%d) too big\n", n);
 363                                 had_error++;
 364                                 continue;
 365                         }
 366                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 367                                 if (!toobig++)
 368                                         dprintf("Too many addresses (%d)\n",
 369                                                 MAXADDRS);
 370                                 cp += n;
 371                                 continue;
 372                         }
 373                         bcopy(cp, *hap++ = bp, n);
 374                         bp += n;
 375                         buflen -= n;
 376                         cp += n;
 377                         break;
 378                 default:
 379                         abort();
 380                 }
 381                 if (!had_error)
 382                         haveanswer++;
 383         }
 384         if (haveanswer) {
 385                 *ap = NULL;
 386                 *hap = NULL;
 387 # if defined(RESOLVSORT)
 388                 /*
 389                  * Note: we sort even if host can take only one address
 390                  * in its return structures - should give it the "best"
 391                  * address in that case, not some random one
 392                  */
 393                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 394                         addrsort(h_addr_ptrs, haveanswer);
 395 # endif /*RESOLVSORT*/
 396                 if (!host.h_name) {
 397                         n = strlen(qname) + 1;  /* for the \0 */
 398                         if (n > buflen)
 399                                 goto try_again;
 400                         strcpy(bp, qname);
 401                         host.h_name = bp;
 402                         bp += n;
 403                         buflen -= n;
 404                 }
 405                 if (_res.options & RES_USE_INET6)
 406                         map_v4v6_hostent(&host, &bp, &buflen);
 407                 __set_h_errno (NETDB_SUCCESS);
 408                 return (&host);
 409         }
 410  try_again:
 411         __set_h_errno (TRY_AGAIN);
 412         return (NULL);
 413 }
 414
 415 struct hostent *
 416 gethostbyname(name)
 417         const char *name;
 418 {
 419         struct hostent *hp;
 420
 421         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 422                 __set_h_errno (NETDB_INTERNAL);
 423                 return (NULL);
 424        }
 425         if (_res.options & RES_USE_INET6) {
 426                 hp = gethostbyname2(name, AF_INET6);
 427                 if (hp)
 428                         return (hp);
 429         }
 430         return (gethostbyname2(name, AF_INET));
 431 }
 432
 433 struct hostent *
 434 gethostbyname2(name, af)
 435         const char *name;
 436         int af;
 437 {
 438         querybuf buf;
 439         register const char *cp;
 440         char *bp;
 441         int n, size, type, len;
 442         extern struct hostent *_gethtbyname2();
 443
 444         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 445                 __set_h_errno (NETDB_INTERNAL);
 446                 return (NULL);
 447         }
 448
 449         switch (af) {
 450         case AF_INET:
 451                 size = INADDRSZ;
 452                 type = T_A;
 453                 break;
 454         case AF_INET6:
 455                 size = IN6ADDRSZ;
 456                 type = T_AAAA;
 457                 break;
 458         default:
 459                 __set_h_errno (NETDB_INTERNAL);
 460                 __set_errno (EAFNOSUPPORT);
 461                 return (NULL);
 462         }
 463
 464         host.h_addrtype = af;
 465         host.h_length = size;
 466
 467         /*
 468          * if there aren't any dots, it could be a user-level alias.
 469          * this is also done in res_query() since we are not the only
 470          * function that looks up host names.
 471          */
 472         if (!strchr(name, '.') && (cp = __hostalias(name)))
 473                 name = cp;
 474
 475         /*
 476          * disallow names consisting only of digits/dots, unless
 477          * they end in a dot.
 478          */
 479         if (isdigit(name[0]))
 480                 for (cp = name;; ++cp) {
 481                         if (!*cp) {
 482                                 if (*--cp == '.')
 483                                         break;
 484                                 /*
 485                                  * All-numeric, no dot at the end.
 486                                  * Fake up a hostent as if we'd actually
 487                                  * done a lookup.
 488                                  */
 489                                 if (inet_pton(af, name, host_addr) <= 0) {
 490                                         __set_h_errno (HOST_NOT_FOUND);
 491                                         return (NULL);
 492                                 }
 493                                 strncpy(hostbuf, name, MAXDNAME);
 494                                 hostbuf[MAXDNAME] = '\0';
 495                                 bp = hostbuf + MAXDNAME;
 496                                 len = sizeof hostbuf - MAXDNAME;
 497                                 host.h_name = hostbuf;
 498                                 host.h_aliases = host_aliases;
 499                                 host_aliases[0] = NULL;
 500                                 h_addr_ptrs[0] = (char *)host_addr;
 501                                 h_addr_ptrs[1] = NULL;
 502                                 host.h_addr_list = h_addr_ptrs;
 503                                 if (_res.options & RES_USE_INET6)
 504                                         map_v4v6_hostent(&host, &bp, &len);
 505                                 __set_h_errno (NETDB_SUCCESS);
 506                                 return (&host);
 507                         }
 508                         if (!isdigit(*cp) && *cp != '.')
 509                                 break;
 510                }
 511         if (isxdigit(name[0]) || name[0] == ':')
 512                 for (cp = name;; ++cp) {
 513                         if (!*cp) {
 514                                 if (*--cp == '.')
 515                                         break;
 516                                 /*
 517                                  * All-IPv6-legal, no dot at the end.
 518                                  * Fake up a hostent as if we'd actually
 519                                  * done a lookup.
 520                                  */
 521                                 if (inet_pton(af, name, host_addr) <= 0) {
 522                                         __set_h_errno (HOST_NOT_FOUND);
 523                                         return (NULL);
 524                                 }
 525                                 strncpy(hostbuf, name, MAXDNAME);
 526                                 hostbuf[MAXDNAME] = '\0';
 527                                 bp = hostbuf + MAXDNAME;
 528                                 len = sizeof hostbuf - MAXDNAME;
 529                                 host.h_name = hostbuf;
 530                                 host.h_aliases = host_aliases;
 531                                 host_aliases[0] = NULL;
 532                                 h_addr_ptrs[0] = (char *)host_addr;
 533                                 h_addr_ptrs[1] = NULL;
 534                                 host.h_addr_list = h_addr_ptrs;
 535                                 __set_h_errno (NETDB_SUCCESS);
 536                                 return (&host);
 537                         }
 538                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
 539                                 break;
 540                 }
 541
 542         if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) {
 543                 dprintf("res_search failed (%d)\n", n);
 544                 if (errno == ECONNREFUSED)
 545                         return (_gethtbyname2(name, af));
 546                 return (NULL);
 547         }
 548         return (getanswer(&buf, n, name, type));
 549 }
 550
 551 struct hostent *
 552 gethostbyaddr(addr, len, af)
 553         const char *addr;       /* XXX should have been def'd as u_char! */
 554         int len, af;
 555 {
 556         const u_char *uaddr = (const u_char *)addr;
 557         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 558         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 559         int n, size;
 560         querybuf buf;
 561         register struct hostent *hp;
 562         char qbuf[MAXDNAME+1], *qp;
 563 #ifdef SUNSECURITY
 564         register struct hostent *rhp;
 565         char **haddr;
 566         u_long old_options;
 567         char hname2[MAXDNAME+1];
 568 #endif /*SUNSECURITY*/
 569         extern struct hostent *_gethtbyaddr();
 570
 571         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 572                 __set_h_errno (NETDB_INTERNAL);
 573                 return (NULL);
 574         }
 575         if (af == AF_INET6 && len == IN6ADDRSZ &&
 576             (!bcmp(uaddr, mapped, sizeof mapped) ||
 577              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 578                 /* Unmap. */
 579                 addr += sizeof mapped;
 580                 uaddr += sizeof mapped;
 581                 af = AF_INET;
 582                 len = INADDRSZ;
 583         }
 584         switch (af) {
 585         case AF_INET:
 586                 size = INADDRSZ;
 587                 break;
 588         case AF_INET6:
 589                 size = IN6ADDRSZ;
 590                 break;
 591         default:
 592                 __set_errno (EAFNOSUPPORT);
 593                 __set_h_errno (NETDB_INTERNAL);
 594                 return (NULL);
 595         }
 596         if (size != len) {
 597                 __set_errno (EINVAL);
 598                 __set_h_errno (NETDB_INTERNAL);
 599                 return (NULL);
 600         }
 601         switch (af) {
 602         case AF_INET:
 603                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 604                                (uaddr[3] & 0xff),
 605                                (uaddr[2] & 0xff),
 606                                (uaddr[1] & 0xff),
 607                                (uaddr[0] & 0xff));
 608                 break;
 609         case AF_INET6:
 610                 qp = qbuf;
 611                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 612                         qp += SPRINTF((qp, "%x.%x.",
 613                                        uaddr[n] & 0xf,
 614                                        (uaddr[n] >> 4) & 0xf));
 615                 }
 616                 strcpy(qp, "ip6.int");
 617                 break;
 618         default:
 619                 abort();
 620         }
 621         n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
 622         if (n < 0) {
 623                 dprintf("res_query failed (%d)\n", n);
 624                 if (errno == ECONNREFUSED)
 625                         return (_gethtbyaddr(addr, len, af));
 626                 return (NULL);
 627         }
 628         if (!(hp = getanswer(&buf, n, qbuf, T_PTR)))
 629                 return (NULL);  /* h_errno was set by getanswer() */
 630 #ifdef SUNSECURITY
 631         if (af == AF_INET) {
 632             /*
 633              * turn off search as the name should be absolute,
 634              * 'localhost' should be matched by defnames
 635              */
 636             strncpy(hname2, hp->h_name, MAXDNAME);
 637             hname2[MAXDNAME] = '\0';
 638             old_options = _res.options;
 639             _res.options &= ~RES_DNSRCH;
 640             _res.options |= RES_DEFNAMES;
 641             if (!(rhp = gethostbyname(hname2))) {
 642                 syslog(LOG_NOTICE|LOG_AUTH,
 643                        "gethostbyaddr: No A record for %s (verifying [%s])",
 644                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 645                 _res.options = old_options;
 646                 __set_h_errno (HOST_NOT_FOUND);
 647                 return (NULL);
 648             }
 649             _res.options = old_options;
 650             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 651                 if (!memcmp(*haddr, addr, INADDRSZ))
 652                         break;
 653             if (!*haddr) {
 654                 syslog(LOG_NOTICE|LOG_AUTH,
 655                        "gethostbyaddr: A record of %s != PTR record [%s]",
 656                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 657                 __set_h_errno (HOST_NOT_FOUND);
 658                 return (NULL);
 659             }
 660         }
 661 #endif /*SUNSECURITY*/
 662         hp->h_addrtype = af;
 663         hp->h_length = len;
 664         bcopy(addr, host_addr, len);
 665         h_addr_ptrs[0] = (char *)host_addr;
 666         h_addr_ptrs[1] = NULL;
 667         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 668                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 669                 hp->h_addrtype = AF_INET6;
 670                 hp->h_length = IN6ADDRSZ;
 671         }
 672         __set_h_errno (NETDB_SUCCESS);
 673         return (hp);
 674 }
 675
 676 void
 677 _sethtent(f)
 678         int f;
 679 {
 680         if (!hostf)
 681                 hostf = fopen(_PATH_HOSTS, "r" );
 682         else
 683                 rewind(hostf);
 684         stayopen = f;
 685 }
 686
 687 void
 688 _endhtent()
 689 {
 690         if (hostf && !stayopen) {
 691                 (void) fclose(hostf);
 692                 hostf = NULL;
 693         }
 694 }
 695
 696 struct hostent *
 697 _gethtent()
 698 {
 699         char *p;
 700         register char *cp, **q;
 701         int af, len;
 702
 703         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
 704                 __set_h_errno (NETDB_INTERNAL);
 705                 return (NULL);
 706         }
 707  again:
 708         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 709                 __set_h_errno (HOST_NOT_FOUND);
 710                 return (NULL);
 711         }
 712         if (*p == '#')
 713                 goto again;
 714         if (!(cp = strpbrk(p, "#\n")))
 715                 goto again;
 716         *cp = '\0';
 717         if (!(cp = strpbrk(p, " \t")))
 718                 goto again;
 719         *cp++ = '\0';
 720         if ((_res.options & RES_USE_INET6) &&
 721             inet_pton(AF_INET6, p, host_addr) > 0) {
 722                 af = AF_INET6;
 723                 len = IN6ADDRSZ;
 724         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 725                 if (_res.options & RES_USE_INET6) {
 726                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 727                         af = AF_INET6;
 728                         len = IN6ADDRSZ;
 729                 } else {
 730                         af = AF_INET;
 731                         len = INADDRSZ;
 732                 }
 733         } else {
 734                 goto again;
 735         }
 736         h_addr_ptrs[0] = (char *)host_addr;
 737         h_addr_ptrs[1] = NULL;
 738         host.h_addr_list = h_addr_ptrs;
 739         host.h_length = len;
 740         host.h_addrtype = af;
 741         while (*cp == ' ' || *cp == '\t')
 742                 cp++;
 743         host.h_name = cp;
 744         q = host.h_aliases = host_aliases;
 745         if (cp = strpbrk(cp, " \t"))
 746                 *cp++ = '\0';
 747         while (cp && *cp) {
 748                 if (*cp == ' ' || *cp == '\t') {
 749                         cp++;
 750                         continue;
 751                 }
 752                 if (q < &host_aliases[MAXALIASES - 1])
 753                         *q++ = cp;
 754                 if (cp = strpbrk(cp, " \t"))
 755                         *cp++ = '\0';
 756         }
 757         *q = NULL;
 758         if (_res.options & RES_USE_INET6) {
 759                 char *bp = hostbuf;
 760                 int buflen = sizeof hostbuf;
 761
 762                 map_v4v6_hostent(&host, &bp, &buflen);
 763         }
 764         __set_h_errno (NETDB_SUCCESS);
 765         return (&host);
 766 }
 767
 768 struct hostent *
 769 _gethtbyname(name)
 770         const char *name;
 771 {
 772         extern struct hostent *_gethtbyname2();
 773         struct hostent *hp;
 774
 775         if (_res.options & RES_USE_INET6) {
 776                 hp = _gethtbyname2(name, AF_INET6);
 777                 if (hp)
 778                         return (hp);
 779         }
 780         return (_gethtbyname2(name, AF_INET));
 781 }
 782
 783 struct hostent *
 784 _gethtbyname2(name, af)
 785         const char *name;
 786         int af;
 787 {
 788         register struct hostent *p;
 789         register char **cp;
 790
 791         _sethtent(0);
 792         while (p = _gethtent()) {
 793                 if (p->h_addrtype != af)
 794                         continue;
 795                 if (strcasecmp(p->h_name, name) == 0)
 796                         break;
 797                 for (cp = p->h_aliases; *cp != 0; cp++)
 798                         if (strcasecmp(*cp, name) == 0)
 799                                 goto found;
 800         }
 801  found:
 802         _endhtent();
 803         return (p);
 804 }
 805
 806 struct hostent *
 807 _gethtbyaddr(addr, len, af)
 808         const char *addr;
 809         int len, af;
 810 {
 811         register struct hostent *p;
 812
 813         _sethtent(0);
 814         while (p = _gethtent())
 815                 if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
 816                         break;
 817         _endhtent();
 818         return (p);
 819 }
 820
 821 static void
 822 map_v4v6_address(src, dst)
 823         const char *src;
 824         char *dst;
 825 {
 826         u_char *p = (u_char *)dst;
 827         char tmp[INADDRSZ];
 828         int i;
 829
 830         /* Stash a temporary copy so our caller can update in place. */
 831         bcopy(src, tmp, INADDRSZ);
 832         /* Mark this ipv6 addr as a mapped ipv4. */
 833         for (i = 0; i < 10; i++)
 834                 *p++ = 0x00;
 835         *p++ = 0xff;
 836         *p++ = 0xff;
 837         /* Retrieve the saved copy and we're done. */
 838         bcopy(tmp, (void*)p, INADDRSZ);
 839 }
 840
 841 static void
 842 map_v4v6_hostent(hp, bpp, lenp)
 843         struct hostent *hp;
 844         char **bpp;
 845         int *lenp;
 846 {
 847         char **ap;
 848
 849         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 850                 return;
 851         hp->h_addrtype = AF_INET6;
 852         hp->h_length = IN6ADDRSZ;
 853         for (ap = hp->h_addr_list; *ap; ap++) {
 854                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 855
 856                 if (*lenp < (i + IN6ADDRSZ)) {
 857                         /* Out of memory.  Truncate address list here.  XXX */
 858                         *ap = NULL;
 859                         return;
 860                 }
 861                 *bpp += i;
 862                 *lenp -= i;
 863                 map_v4v6_address(*ap, *bpp);
 864                 *ap = *bpp;
 865                 *bpp += IN6ADDRSZ;
 866                 *lenp -= IN6ADDRSZ;
 867         }
 868 }
 869
 870 #ifdef RESOLVSORT
 871 static void
 872 addrsort(ap, num)
 873         char **ap;
 874         int num;
 875 {
 876         int i, j;
 877         char **p;
 878         short aval[MAXADDRS];
 879         int needsort = 0;
 880
 881         p = ap;
 882         for (i = 0; i < num; i++, p++) {
 883             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 884                 if (_res.sort_list[j].addr.s_addr ==
 885                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 886                         break;
 887             aval[i] = j;
 888             if (needsort == 0 && i > 0 && j < aval[i-1])
 889                 needsort = i;
 890         }
 891         if (!needsort)
 892             return;
 893
 894         while (needsort < num) {
 895             for (j = needsort - 1; j >= 0; j--) {
 896                 if (aval[j] > aval[j+1]) {
 897                     char *hp;
 898
 899                     i = aval[j];
 900                     aval[j] = aval[j+1];
 901                     aval[j+1] = i;
 902
 903                     hp = ap[j];
 904                     ap[j] = ap[j+1];
 905                     ap[j+1] = hp;
 906
 907                 } else
 908                     break;
 909             }
 910             needsort++;
 911         }
 912 }
 913 #endif
 914
 915 #if defined(BSD43_BSD43_NFS) || defined(sun)
 916 /* some libc's out there are bound internally to these names (UMIPS) */
 917 void
 918 ht_sethostent(stayopen)
 919         int stayopen;
 920 {
 921         _sethtent(stayopen);
 922 }
 923
 924 void
 925 ht_endhostent()
 926 {
 927         _endhtent();
 928 }
 929
 930 struct hostent *
 931 ht_gethostbyname(name)
 932         char *name;
 933 {
 934         return (_gethtbyname(name));
 935 }
 936
 937 struct hostent *
 938 ht_gethostbyaddr(addr, len, af)
 939         const char *addr;
 940         int len, af;
 941 {
 942         return (_gethtbyaddr(addr, len, af));
 943 }
 944
 945 struct hostent *
 946 gethostent()
 947 {
 948         return (_gethtent());
 949 }
 950
 951 void
 952 dns_service()
 953 {
 954         return;
 955 }
 956
 957 #undef dn_skipname
 958 dn_skipname(comp_dn, eom)
 959         const u_char *comp_dn, *eom;
 960 {
 961         return (__dn_skipname(comp_dn, eom));
 962 }
 963 #endif /*old-style libc with yp junk in it*/