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 == T_SIG) || (type == T_KEY) || (type == T_NXT)) {
 337                         /* We don't support DNSSEC yet.  For now, ignore
 338                          * the record and send a low priority message
 339                          * to syslog.
 340                          */
 341                         syslog(LOG_DEBUG|LOG_AUTH,
 342                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 343                                qname, p_class(C_IN), p_type(qtype),
 344                                p_type(type));
 345                         cp += n;
 346                         continue;
 347                 }
 348                 if (type != qtype) {
 349                         syslog(LOG_NOTICE|LOG_AUTH,
 350                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 351                                qname, p_class(C_IN), p_type(qtype),
 352                                p_type(type));
 353                         cp += n;
 354                         continue;               /* XXX - had_error++ ? */
 355                 }
 356                 switch (type) {
 357                 case T_PTR:
 358                         if (strcasecmp(tname, bp) != 0) {
 359                                 syslog(LOG_NOTICE|LOG_AUTH,
 360                                        AskedForGot, qname, bp);
 361                                 cp += n;
 362                                 continue;       /* XXX - had_error++ ? */
 363                         }
 364                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 365                         if ((n < 0) || !res_hnok(bp)) {
 366                                 had_error++;
 367                                 break;
 368                         }
 369 #if MULTI_PTRS_ARE_ALIASES
 370                         cp += n;
 371                         if (cp != erdata) {
 372                                 __set_h_errno (NO_RECOVERY);
 373                                 return (NULL);
 374                         }
 375                         if (!haveanswer)
 376                                 host.h_name = bp;
 377                         else if (ap < &host_aliases[MAXALIASES-1])
 378                                 *ap++ = bp;
 379                         else
 380                                 n = -1;
 381                         if (n != -1) {
 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                         }
 390                         break;
 391 #else
 392                         host.h_name = bp;
 393                         if (_res.options & RES_USE_INET6) {
 394                                 n = strlen(bp) + 1;     /* for the \0 */
 395                                 if (n >= MAXHOSTNAMELEN) {
 396                                         had_error++;
 397                                         break;
 398                                 }
 399                                 bp += n;
 400                                 buflen -= n;
 401                                 map_v4v6_hostent(&host, &bp, &buflen);
 402                         }
 403                         __set_h_errno (NETDB_SUCCESS);
 404                         return (&host);
 405 #endif
 406                 case T_A:
 407                 case T_AAAA:
 408                         if (strcasecmp(host.h_name, bp) != 0) {
 409                                 syslog(LOG_NOTICE|LOG_AUTH,
 410                                        AskedForGot, host.h_name, bp);
 411                                 cp += n;
 412                                 continue;       /* XXX - had_error++ ? */
 413                         }
 414                         if (n != host.h_length) {
 415                                 cp += n;
 416                                 continue;
 417                         }
 418                         if (!haveanswer) {
 419                                 register int nn;
 420
 421                                 host.h_name = bp;
 422                                 nn = strlen(bp) + 1;    /* for the \0 */
 423                                 bp += nn;
 424                                 buflen -= nn;
 425                         }
 426
 427                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 428
 429                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 430                                 dprintf("size (%d) too big\n", n);
 431                                 had_error++;
 432                                 continue;
 433                         }
 434                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 435                                 if (!toobig++) {
 436                                         dprintf("Too many addresses (%d)\n",
 437                                                 MAXADDRS);
 438                                 }
 439                                 cp += n;
 440                                 continue;
 441                         }
 442                         bcopy(cp, *hap++ = bp, n);
 443                         bp += n;
 444                         buflen -= n;
 445                         cp += n;
 446                         if (cp != erdata) {
 447                                 __set_h_errno (NO_RECOVERY);
 448                                 return (NULL);
 449                         }
 450                         break;
 451                 default:
 452                         abort();
 453                 }
 454                 if (!had_error)
 455                         haveanswer++;
 456         }
 457         if (haveanswer) {
 458                 *ap = NULL;
 459                 *hap = NULL;
 460 # if defined(RESOLVSORT)
 461                 /*
 462                  * Note: we sort even if host can take only one address
 463                  * in its return structures - should give it the "best"
 464                  * address in that case, not some random one
 465                  */
 466                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 467                         addrsort(h_addr_ptrs, haveanswer);
 468 # endif /*RESOLVSORT*/
 469                 if (!host.h_name) {
 470                         n = strlen(qname) + 1;  /* for the \0 */
 471                         if (n > buflen || n >= MAXHOSTNAMELEN)
 472                                 goto no_recovery;
 473                         strcpy(bp, qname);
 474                         host.h_name = bp;
 475                         bp += n;
 476                         buflen -= n;
 477                 }
 478                 if (_res.options & RES_USE_INET6)
 479                         map_v4v6_hostent(&host, &bp, &buflen);
 480                 __set_h_errno (NETDB_SUCCESS);
 481                 return (&host);
 482         }
 483  no_recovery:
 484         __set_h_errno (NO_RECOVERY);
 485         return (NULL);
 486 }
 487
 488 struct hostent *
 489 gethostbyname(name)
 490         const char *name;
 491 {
 492         struct hostent *hp;
 493
 494         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 495                 __set_h_errno (NETDB_INTERNAL);
 496                 return (NULL);
 497        }
 498         if (_res.options & RES_USE_INET6) {
 499                 hp = gethostbyname2(name, AF_INET6);
 500                 if (hp)
 501                         return (hp);
 502         }
 503         return (gethostbyname2(name, AF_INET));
 504 }
 505
 506 struct hostent *
 507 gethostbyname2(name, af)
 508         const char *name;
 509         int af;
 510 {
 511         querybuf buf;
 512         register const char *cp;
 513         char *bp;
 514         int n, size, type, len;
 515         extern struct hostent *_gethtbyname2();
 516
 517         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 518                 __set_h_errno (NETDB_INTERNAL);
 519                 return (NULL);
 520         }
 521
 522         switch (af) {
 523         case AF_INET:
 524                 size = INADDRSZ;
 525                 type = T_A;
 526                 break;
 527         case AF_INET6:
 528                 size = IN6ADDRSZ;
 529                 type = T_AAAA;
 530                 break;
 531         default:
 532                 __set_h_errno (NETDB_INTERNAL);
 533                 __set_errno (EAFNOSUPPORT);
 534                 return (NULL);
 535         }
 536
 537         host.h_addrtype = af;
 538         host.h_length = size;
 539
 540         /*
 541          * if there aren't any dots, it could be a user-level alias.
 542          * this is also done in res_query() since we are not the only
 543          * function that looks up host names.
 544          */
 545         if (!strchr(name, '.') && (cp = __hostalias(name)))
 546                 name = cp;
 547
 548         /*
 549          * disallow names consisting only of digits/dots, unless
 550          * they end in a dot.
 551          */
 552         if (isdigit(name[0]))
 553                 for (cp = name;; ++cp) {
 554                         if (!*cp) {
 555                                 if (*--cp == '.')
 556                                         break;
 557                                 /*
 558                                  * All-numeric, no dot at the end.
 559                                  * Fake up a hostent as if we'd actually
 560                                  * done a lookup.
 561                                  */
 562                                 if (inet_pton(af, name, host_addr) <= 0) {
 563                                         __set_h_errno (HOST_NOT_FOUND);
 564                                         return (NULL);
 565                                 }
 566                                 strncpy(hostbuf, name, MAXDNAME);
 567                                 hostbuf[MAXDNAME] = '\0';
 568                                 bp = hostbuf + MAXDNAME;
 569                                 len = sizeof hostbuf - MAXDNAME;
 570                                 host.h_name = hostbuf;
 571                                 host.h_aliases = host_aliases;
 572                                 host_aliases[0] = NULL;
 573                                 h_addr_ptrs[0] = (char *)host_addr;
 574                                 h_addr_ptrs[1] = NULL;
 575                                 host.h_addr_list = h_addr_ptrs;
 576                                 if (_res.options & RES_USE_INET6)
 577                                         map_v4v6_hostent(&host, &bp, &len);
 578                                 __set_h_errno (NETDB_SUCCESS);
 579                                 return (&host);
 580                         }
 581                         if (!isdigit(*cp) && *cp != '.')
 582                                 break;
 583                }
 584         if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
 585             name[0] == ':')
 586                 for (cp = name;; ++cp) {
 587                         if (!*cp) {
 588                                 if (*--cp == '.')
 589                                         break;
 590                                 /*
 591                                  * All-IPv6-legal, no dot at the end.
 592                                  * Fake up a hostent as if we'd actually
 593                                  * done a lookup.
 594                                  */
 595                                 if (inet_pton(af, name, host_addr) <= 0) {
 596                                         __set_h_errno (HOST_NOT_FOUND);
 597                                         return (NULL);
 598                                 }
 599                                 strncpy(hostbuf, name, MAXDNAME);
 600                                 hostbuf[MAXDNAME] = '\0';
 601                                 bp = hostbuf + MAXDNAME;
 602                                 len = sizeof hostbuf - MAXDNAME;
 603                                 host.h_name = hostbuf;
 604                                 host.h_aliases = host_aliases;
 605                                 host_aliases[0] = NULL;
 606                                 h_addr_ptrs[0] = (char *)host_addr;
 607                                 h_addr_ptrs[1] = NULL;
 608                                 host.h_addr_list = h_addr_ptrs;
 609                                 __set_h_errno (NETDB_SUCCESS);
 610                                 return (&host);
 611                         }
 612                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
 613                                 break;
 614                 }
 615
 616         if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf.buf))) < 0) {
 617                 dprintf("res_search failed (%d)\n", n);
 618                 if (errno == ECONNREFUSED)
 619                         return (_gethtbyname2(name, af));
 620                 return (NULL);
 621         }
 622         return (getanswer(&buf, n, name, type));
 623 }
 624
 625 struct hostent *
 626 gethostbyaddr(addr, len, af)
 627         const char *addr;       /* XXX should have been def'd as u_char! */
 628         int len, af;
 629 {
 630         const u_char *uaddr = (const u_char *)addr;
 631         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 632         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 633         int n, size;
 634         querybuf buf;
 635         register struct hostent *hp;
 636         char qbuf[MAXDNAME+1], *qp;
 637 #ifdef SUNSECURITY
 638         register struct hostent *rhp;
 639         char **haddr;
 640         u_long old_options;
 641         char hname2[MAXDNAME+1];
 642 #endif /*SUNSECURITY*/
 643         extern struct hostent *_gethtbyaddr();
 644
 645         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 646                 __set_h_errno (NETDB_INTERNAL);
 647                 return (NULL);
 648         }
 649         if (af == AF_INET6 && len == IN6ADDRSZ &&
 650             (!bcmp(uaddr, mapped, sizeof mapped) ||
 651              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 652                 /* Unmap. */
 653                 addr += sizeof mapped;
 654                 uaddr += sizeof mapped;
 655                 af = AF_INET;
 656                 len = INADDRSZ;
 657         }
 658         switch (af) {
 659         case AF_INET:
 660                 size = INADDRSZ;
 661                 break;
 662         case AF_INET6:
 663                 size = IN6ADDRSZ;
 664                 break;
 665         default:
 666                 __set_errno (EAFNOSUPPORT);
 667                 __set_h_errno (NETDB_INTERNAL);
 668                 return (NULL);
 669         }
 670         if (size != len) {
 671                 __set_errno (EINVAL);
 672                 __set_h_errno (NETDB_INTERNAL);
 673                 return (NULL);
 674         }
 675         switch (af) {
 676         case AF_INET:
 677                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 678                                (uaddr[3] & 0xff),
 679                                (uaddr[2] & 0xff),
 680                                (uaddr[1] & 0xff),
 681                                (uaddr[0] & 0xff));
 682                 break;
 683         case AF_INET6:
 684                 qp = qbuf;
 685                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 686                         qp += SPRINTF((qp, "%x.%x.",
 687                                        uaddr[n] & 0xf,
 688                                        (uaddr[n] >> 4) & 0xf));
 689                 }
 690                 strcpy(qp, "ip6.int");
 691                 break;
 692         default:
 693                 abort();
 694         }
 695         n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
 696         if (n < 0) {
 697                 dprintf("res_query failed (%d)\n", n);
 698                 if (errno == ECONNREFUSED)
 699                         return (_gethtbyaddr(addr, len, af));
 700                 return (NULL);
 701         }
 702         if (!(hp = getanswer(&buf, n, qbuf, T_PTR)))
 703                 return (NULL);  /* h_errno was set by getanswer() */
 704 #ifdef SUNSECURITY
 705         if (af == AF_INET) {
 706             /*
 707              * turn off search as the name should be absolute,
 708              * 'localhost' should be matched by defnames
 709              */
 710             strncpy(hname2, hp->h_name, MAXDNAME);
 711             hname2[MAXDNAME] = '\0';
 712             old_options = _res.options;
 713             _res.options &= ~RES_DNSRCH;
 714             _res.options |= RES_DEFNAMES;
 715             if (!(rhp = gethostbyname(hname2))) {
 716                 syslog(LOG_NOTICE|LOG_AUTH,
 717                        "gethostbyaddr: No A record for %s (verifying [%s])",
 718                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 719                 _res.options = old_options;
 720                 __set_h_errno (HOST_NOT_FOUND);
 721                 return (NULL);
 722             }
 723             _res.options = old_options;
 724             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 725                 if (!memcmp(*haddr, addr, INADDRSZ))
 726                         break;
 727             if (!*haddr) {
 728                 syslog(LOG_NOTICE|LOG_AUTH,
 729                        "gethostbyaddr: A record of %s != PTR record [%s]",
 730                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 731                 __set_h_errno (HOST_NOT_FOUND);
 732                 return (NULL);
 733             }
 734         }
 735 #endif /*SUNSECURITY*/
 736         hp->h_addrtype = af;
 737         hp->h_length = len;
 738         bcopy(addr, host_addr, len);
 739         h_addr_ptrs[0] = (char *)host_addr;
 740         h_addr_ptrs[1] = NULL;
 741         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 742                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 743                 hp->h_addrtype = AF_INET6;
 744                 hp->h_length = IN6ADDRSZ;
 745         }
 746         __set_h_errno (NETDB_SUCCESS);
 747         return (hp);
 748 }
 749
 750 void
 751 _sethtent(f)
 752         int f;
 753 {
 754         if (!hostf)
 755                 hostf = fopen(_PATH_HOSTS, "r" );
 756         else
 757                 rewind(hostf);
 758         stayopen = f;
 759 }
 760
 761 void
 762 _endhtent()
 763 {
 764         if (hostf && !stayopen) {
 765                 (void) fclose(hostf);
 766                 hostf = NULL;
 767         }
 768 }
 769
 770 struct hostent *
 771 _gethtent()
 772 {
 773         char *p;
 774         register char *cp, **q;
 775         int af, len;
 776
 777         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
 778                 __set_h_errno (NETDB_INTERNAL);
 779                 return (NULL);
 780         }
 781  again:
 782         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 783                 __set_h_errno (HOST_NOT_FOUND);
 784                 return (NULL);
 785         }
 786         if (*p == '#')
 787                 goto again;
 788         if (!(cp = strpbrk(p, "#\n")))
 789                 goto again;
 790         *cp = '\0';
 791         if (!(cp = strpbrk(p, " \t")))
 792                 goto again;
 793         *cp++ = '\0';
 794         if (inet_pton(AF_INET6, p, host_addr) > 0) {
 795                 af = AF_INET6;
 796                 len = IN6ADDRSZ;
 797         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 798                 if (_res.options & RES_USE_INET6) {
 799                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 800                         af = AF_INET6;
 801                         len = IN6ADDRSZ;
 802                 } else {
 803                         af = AF_INET;
 804                         len = INADDRSZ;
 805                 }
 806         } else {
 807                 goto again;
 808         }
 809         h_addr_ptrs[0] = (char *)host_addr;
 810         h_addr_ptrs[1] = NULL;
 811         host.h_addr_list = h_addr_ptrs;
 812         host.h_length = len;
 813         host.h_addrtype = af;
 814         while (*cp == ' ' || *cp == '\t')
 815                 cp++;
 816         host.h_name = cp;
 817         q = host.h_aliases = host_aliases;
 818         if (cp = strpbrk(cp, " \t"))
 819                 *cp++ = '\0';
 820         while (cp && *cp) {
 821                 if (*cp == ' ' || *cp == '\t') {
 822                         cp++;
 823                         continue;
 824                 }
 825                 if (q < &host_aliases[MAXALIASES - 1])
 826                         *q++ = cp;
 827                 if (cp = strpbrk(cp, " \t"))
 828                         *cp++ = '\0';
 829         }
 830         *q = NULL;
 831         __set_h_errno (NETDB_SUCCESS);
 832         return (&host);
 833 }
 834
 835 struct hostent *
 836 _gethtbyname(name)
 837         const char *name;
 838 {
 839         extern struct hostent *_gethtbyname2();
 840         struct hostent *hp;
 841
 842         if (_res.options & RES_USE_INET6) {
 843                 hp = _gethtbyname2(name, AF_INET6);
 844                 if (hp)
 845                         return (hp);
 846         }
 847         return (_gethtbyname2(name, AF_INET));
 848 }
 849
 850 struct hostent *
 851 _gethtbyname2(name, af)
 852         const char *name;
 853         int af;
 854 {
 855         register struct hostent *p;
 856         register char **cp;
 857
 858         _sethtent(0);
 859         while (p = _gethtent()) {
 860                 if (p->h_addrtype != af)
 861                         continue;
 862                 if (strcasecmp(p->h_name, name) == 0)
 863                         break;
 864                 for (cp = p->h_aliases; *cp != 0; cp++)
 865                         if (strcasecmp(*cp, name) == 0)
 866                                 goto found;
 867         }
 868  found:
 869         _endhtent();
 870         return (p);
 871 }
 872
 873 struct hostent *
 874 _gethtbyaddr(addr, len, af)
 875         const char *addr;
 876         int len, af;
 877 {
 878         register struct hostent *p;
 879
 880         _sethtent(0);
 881         while (p = _gethtent())
 882                 if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
 883                         break;
 884         _endhtent();
 885         return (p);
 886 }
 887
 888 static void
 889 map_v4v6_address(src, dst)
 890         const char *src;
 891         char *dst;
 892 {
 893         u_char *p = (u_char *)dst;
 894         char tmp[INADDRSZ];
 895         int i;
 896
 897         /* Stash a temporary copy so our caller can update in place. */
 898         bcopy(src, tmp, INADDRSZ);
 899         /* Mark this ipv6 addr as a mapped ipv4. */
 900         for (i = 0; i < 10; i++)
 901                 *p++ = 0x00;
 902         *p++ = 0xff;
 903         *p++ = 0xff;
 904         /* Retrieve the saved copy and we're done. */
 905         bcopy(tmp, (void*)p, INADDRSZ);
 906 }
 907
 908 static void
 909 map_v4v6_hostent(hp, bpp, lenp)
 910         struct hostent *hp;
 911         char **bpp;
 912         int *lenp;
 913 {
 914         char **ap;
 915
 916         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 917                 return;
 918         hp->h_addrtype = AF_INET6;
 919         hp->h_length = IN6ADDRSZ;
 920         for (ap = hp->h_addr_list; *ap; ap++) {
 921                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 922
 923                 if (*lenp < (i + IN6ADDRSZ)) {
 924                         /* Out of memory.  Truncate address list here.  XXX */
 925                         *ap = NULL;
 926                         return;
 927                 }
 928                 *bpp += i;
 929                 *lenp -= i;
 930                 map_v4v6_address(*ap, *bpp);
 931                 *ap = *bpp;
 932                 *bpp += IN6ADDRSZ;
 933                 *lenp -= IN6ADDRSZ;
 934         }
 935 }
 936
 937 #ifdef RESOLVSORT
 938 extern void
 939 addrsort(ap, num)
 940         char **ap;
 941         int num;
 942 {
 943         int i, j;
 944         char **p;
 945         short aval[MAXADDRS];
 946         int needsort = 0;
 947
 948         p = ap;
 949         for (i = 0; i < num; i++, p++) {
 950             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 951                 if (_res.sort_list[j].addr.s_addr ==
 952                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 953                         break;
 954             aval[i] = j;
 955             if (needsort == 0 && i > 0 && j < aval[i-1])
 956                 needsort = i;
 957         }
 958         if (!needsort)
 959             return;
 960
 961         while (needsort < num) {
 962             for (j = needsort - 1; j >= 0; j--) {
 963                 if (aval[j] > aval[j+1]) {
 964                     char *hp;
 965
 966                     i = aval[j];
 967                     aval[j] = aval[j+1];
 968                     aval[j+1] = i;
 969
 970                     hp = ap[j];
 971                     ap[j] = ap[j+1];
 972                     ap[j+1] = hp;
 973
 974                 } else
 975                     break;
 976             }
 977             needsort++;
 978         }
 979 }
 980 #endif
 981
 982 #if defined(BSD43_BSD43_NFS) || defined(sun)
 983 /* some libc's out there are bound internally to these names (UMIPS) */
 984 void
 985 ht_sethostent(stayopen)
 986         int stayopen;
 987 {
 988         _sethtent(stayopen);
 989 }
 990
 991 void
 992 ht_endhostent()
 993 {
 994         _endhtent();
 995 }
 996
 997 struct hostent *
 998 ht_gethostbyname(name)
 999         char *name;
1000 {
1001         return (_gethtbyname(name));
1002 }
1003
1004 struct hostent *
1005 ht_gethostbyaddr(addr, len, af)
1006         const char *addr;
1007         int len, af;
1008 {
1009         return (_gethtbyaddr(addr, len, af));
1010 }
1011
1012 struct hostent *
1013 gethostent()
1014 {
1015         return (_gethtent());
1016 }
1017
1018 void
1019 dns_service()
1020 {
1021         return;
1022 }
1023
1024 #undef dn_skipname
1025 dn_skipname(comp_dn, eom)
1026         const u_char *comp_dn, *eom;
1027 {
1028         return (__dn_skipname(comp_dn, eom));
1029 }
1030 #endif /*old-style libc with yp junk in it*/