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