resolv/gethnamaddr.c

   1 /*
   2  * ++Copyright++ 1985, 1988, 1993
   3  * -
   4  * Copyright (c) 1985, 1988, 1993
   5  *    The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 4. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  * -
  31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  32  *
  33  * Permission to use, copy, modify, and distribute this software for any
  34  * purpose with or without fee is hereby granted, provided that the above
  35  * copyright notice and this permission notice appear in all copies, and that
  36  * the name of Digital Equipment Corporation not be used in advertising or
  37  * publicity pertaining to distribution of the document or software without
  38  * specific, written prior permission.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  47  * SOFTWARE.
  48  * -
  49  * --Copyright--
  50  */
  51
  52 #if defined(LIBC_SCCS) && !defined(lint)
  53 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
  54 static char rcsid[] = "$Id$";
  55 #endif /* LIBC_SCCS and not lint */
  56
  57 #include <sys/types.h>
  58 #include <sys/param.h>
  59 #include <sys/socket.h>
  60 #include <netinet/in.h>
  61 #include <arpa/inet.h>
  62 #include <arpa/nameser.h>
  63
  64 #include <stdio.h>
  65 #include <netdb.h>
  66 #include <resolv.h>
  67 #include <ctype.h>
  68 #include <errno.h>
  69 #include <syslog.h>
  70
  71 #ifndef LOG_AUTH
  72 # define LOG_AUTH 0
  73 #endif
  74
  75 #define MULTI_PTRS_ARE_ALIASES 1        /* XXX - experimental */
  76
  77 #if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
  78 # include <stdlib.h>
  79 # include <string.h>
  80 #else
  81 # include "../conf/portability.h"
  82 #endif
  83
  84 #if defined(USE_OPTIONS_H)
  85 # include <../conf/options.h>
  86 #endif
  87
  88 #ifdef SPRINTF_CHAR
  89 # define SPRINTF(x) strlen(sprintf/**/x)
  90 #else
  91 # define SPRINTF(x) ((size_t)sprintf x)
  92 #endif
  93
  94 #define MAXALIASES      35
  95 #define MAXADDRS        35
  96
  97 static const char AskedForGot[] =
  98                           "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
  99
 100 static char *h_addr_ptrs[MAXADDRS + 1];
 101
 102 static struct hostent host;
 103 static char *host_aliases[MAXALIASES];
 104 static char hostbuf[8*1024];
 105 static u_char host_addr[16];    /* IPv4 or IPv6 */
 106 static FILE *hostf = NULL;
 107 static int stayopen = 0;
 108
 109 static void map_v4v6_address __P((const char *src, char *dst));
 110 static void map_v4v6_hostent __P((struct hostent *hp, char **bp, int *len));
 111
 112 #ifdef RESOLVSORT
 113 extern void addrsort __P((char **, int));
 114 #endif
 115
 116 #if PACKETSZ > 1024
 117 #define MAXPACKET       PACKETSZ
 118 #else
 119 #define MAXPACKET       1024
 120 #endif
 121
 122 /* As per RFC 1034 and 1035 a host name cannot exceed 255 octets in length.  */
 123 #ifdef MAXHOSTNAMELEN
 124 # undef MAXHOSTNAMELEN
 125 #endif
 126 #define MAXHOSTNAMELEN 256
 127
 128 typedef union {
 129     HEADER hdr;
 130     u_char buf[MAXPACKET];
 131 } querybuf;
 132
 133 typedef union {
 134     int32_t al;
 135     char ac;
 136 } align;
 137
 138 #ifndef h_errno
 139 extern int h_errno;
 140 #endif
 141
 142 #ifdef DEBUG
 143 static void
 144 dprintf(msg, num)
 145         char *msg;
 146         int num;
 147 {
 148         if (_res.options & RES_DEBUG) {
 149                 int save = errno;
 150
 151                 printf(msg, num);
 152                 __set_errno (save);
 153         }
 154 }
 155 #else
 156 # define dprintf(msg, num) /*nada*/
 157 #endif
 158
 159 #define BOUNDED_INCR(x) \
 160         do { \
 161                 cp += x; \
 162                 if (cp > eom) { \
 163                         __set_h_errno (NO_RECOVERY); \
 164                         return (NULL); \
 165                 } \
 166         } while (0)
 167
 168 #define BOUNDS_CHECK(ptr, count) \
 169         do { \
 170                 if ((ptr) + (count) > eom) { \
 171                         __set_h_errno (NO_RECOVERY); \
 172                         return (NULL); \
 173                 } \
 174         } while (0)
 175
 176
 177 static struct hostent *
 178 getanswer(answer, anslen, qname, qtype)
 179         const querybuf *answer;
 180         int anslen;
 181         const char *qname;
 182         int qtype;
 183 {
 184         register const HEADER *hp;
 185         register const u_char *cp;
 186         register int n;
 187         const u_char *eom, *erdata;
 188         char *bp, **ap, **hap;
 189         int type, class, buflen, ancount, qdcount;
 190         int haveanswer, had_error;
 191         int toobig = 0;
 192         char tbuf[MAXDNAME];
 193         const char *tname;
 194         int (*name_ok) __P((const char *));
 195
 196         tname = qname;
 197         host.h_name = NULL;
 198         eom = answer->buf + anslen;
 199         switch (qtype) {
 200         case T_A:
 201         case T_AAAA:
 202                 name_ok = res_hnok;
 203                 break;
 204         case T_PTR:
 205                 name_ok = res_dnok;
 206                 break;
 207         default:
 208                 return (NULL);  /* XXX should be abort(); */
 209         }
 210         /*
 211          * find first satisfactory answer
 212          */
 213         hp = &answer->hdr;
 214         ancount = ntohs(hp->ancount);
 215         qdcount = ntohs(hp->qdcount);
 216         bp = hostbuf;
 217         buflen = sizeof hostbuf;
 218         cp = answer->buf;
 219         BOUNDED_INCR(HFIXEDSZ);
 220         if (qdcount != 1) {
 221                 __set_h_errno (NO_RECOVERY);
 222                 return (NULL);
 223         }
 224         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 225         if ((n < 0) || !(*name_ok)(bp)) {
 226                 __set_h_errno (NO_RECOVERY);
 227                 return (NULL);
 228         }
 229         BOUNDED_INCR(n + QFIXEDSZ);
 230         if (qtype == T_A || qtype == T_AAAA) {
 231                 /* res_send() has already verified that the query name is the
 232                  * same as the one we sent; this just gets the expanded name
 233                  * (i.e., with the succeeding search-domain tacked on).
 234                  */
 235                 n = strlen(bp) + 1;             /* for the \0 */
 236                 if (n >= MAXHOSTNAMELEN) {
 237                         __set_h_errno (NO_RECOVERY);
 238                         return (NULL);
 239                 }
 240                 host.h_name = bp;
 241                 bp += n;
 242                 buflen -= n;
 243                 /* The qname can be abbreviated, but h_name is now absolute. */
 244                 qname = host.h_name;
 245         }
 246         ap = host_aliases;
 247         *ap = NULL;
 248         host.h_aliases = host_aliases;
 249         hap = h_addr_ptrs;
 250         *hap = NULL;
 251         host.h_addr_list = h_addr_ptrs;
 252         haveanswer = 0;
 253         had_error = 0;
 254         while (ancount-- > 0 && cp < eom && !had_error) {
 255                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 256                 if ((n < 0) || !(*name_ok)(bp)) {
 257                         had_error++;
 258                         continue;
 259                 }
 260                 cp += n;                        /* name */
 261                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 262                 type = ns_get16(cp);
 263                 cp += INT16SZ;                  /* type */
 264                 class = ns_get16(cp);
 265                 cp += INT16SZ + INT32SZ;        /* class, TTL */
 266                 n = ns_get16(cp);
 267                 cp += INT16SZ;                  /* len */
 268                 BOUNDS_CHECK(cp, n);
 269                 erdata = cp + n;
 270                 if (class != C_IN) {
 271                         /* XXX - debug? syslog? */
 272                         cp += n;
 273                         continue;               /* XXX - had_error++ ? */
 274                 }
 275                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 276                         if (ap >= &host_aliases[MAXALIASES-1])
 277                                 continue;
 278                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 279                         if ((n < 0) || !(*name_ok)(tbuf)) {
 280                                 had_error++;
 281                                 continue;
 282                         }
 283                         cp += n;
 284                         if (cp != erdata) {
 285                                 __set_h_errno (NO_RECOVERY);
 286                                 return (NULL);
 287                         }
 288                         /* Store alias. */
 289                         *ap++ = bp;
 290                         n = strlen(bp) + 1;     /* for the \0 */
 291                         if (n >= MAXHOSTNAMELEN) {
 292                                 had_error++;
 293                                 continue;
 294                         }
 295                         bp += n;
 296                         buflen -= n;
 297                         /* Get canonical name. */
 298                         n = strlen(tbuf) + 1;   /* for the \0 */
 299                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 300                                 had_error++;
 301                                 continue;
 302                         }
 303                         strcpy(bp, tbuf);
 304                         host.h_name = bp;
 305                         bp += n;
 306                         buflen -= n;
 307                         continue;
 308                 }
 309                 if (qtype == T_PTR && type == T_CNAME) {
 310                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 311                         if (n < 0 || !res_dnok(tbuf)) {
 312                                 had_error++;
 313                                 continue;
 314                         }
 315                         cp += n;
 316                         if (cp != erdata) {
 317                                 __set_h_errno (NO_RECOVERY);
 318                                 return (NULL);
 319                         }
 320                         /* Get canonical name. */
 321                         n = strlen(tbuf) + 1;   /* for the \0 */
 322                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 323                                 had_error++;
 324                                 continue;
 325                         }
 326                         strcpy(bp, tbuf);
 327                         tname = bp;
 328                         bp += n;
 329                         buflen -= n;
 330                         continue;
 331                 }
 332                 if ((type == T_SIG) || (type == T_KEY) || (type == T_NXT)) {
 333                         /* We don't support DNSSEC yet.  For now, ignore
 334                          * the record and send a low priority message
 335                          * to syslog.
 336                          */
 337                         syslog(LOG_DEBUG|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;
 343                 }
 344                 if (type != qtype) {
 345                         syslog(LOG_NOTICE|LOG_AUTH,
 346                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 347                                qname, p_class(C_IN), p_type(qtype),
 348                                p_type(type));
 349                         cp += n;
 350                         continue;               /* XXX - had_error++ ? */
 351                 }
 352                 switch (type) {
 353                 case T_PTR:
 354                         if (strcasecmp(tname, bp) != 0) {
 355                                 syslog(LOG_NOTICE|LOG_AUTH,
 356                                        AskedForGot, qname, bp);
 357                                 cp += n;
 358                                 continue;       /* XXX - had_error++ ? */
 359                         }
 360                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 361                         if ((n < 0) || !res_hnok(bp)) {
 362                                 had_error++;
 363                                 break;
 364                         }
 365 #if MULTI_PTRS_ARE_ALIASES
 366                         cp += n;
 367                         if (cp != erdata) {
 368                                 __set_h_errno (NO_RECOVERY);
 369                                 return (NULL);
 370                         }
 371                         if (!haveanswer)
 372                                 host.h_name = bp;
 373                         else if (ap < &host_aliases[MAXALIASES-1])
 374                                 *ap++ = bp;
 375                         else
 376                                 n = -1;
 377                         if (n != -1) {
 378                                 n = strlen(bp) + 1;     /* for the \0 */
 379                                 if (n >= MAXHOSTNAMELEN) {
 380                                         had_error++;
 381                                         break;
 382                                 }
 383                                 bp += n;
 384                                 buflen -= n;
 385                         }
 386                         break;
 387 #else
 388                         host.h_name = bp;
 389                         if (_res.options & RES_USE_INET6) {
 390                                 n = strlen(bp) + 1;     /* for the \0 */
 391                                 if (n >= MAXHOSTNAMELEN) {
 392                                         had_error++;
 393                                         break;
 394                                 }
 395                                 bp += n;
 396                                 buflen -= n;
 397                                 map_v4v6_hostent(&host, &bp, &buflen);
 398                         }
 399                         __set_h_errno (NETDB_SUCCESS);
 400                         return (&host);
 401 #endif
 402                 case T_A:
 403                 case T_AAAA:
 404                         if (strcasecmp(host.h_name, bp) != 0) {
 405                                 syslog(LOG_NOTICE|LOG_AUTH,
 406                                        AskedForGot, host.h_name, bp);
 407                                 cp += n;
 408                                 continue;       /* XXX - had_error++ ? */
 409                         }
 410                         if (n != host.h_length) {
 411                                 cp += n;
 412                                 continue;
 413                         }
 414                         if (!haveanswer) {
 415                                 register int nn;
 416
 417                                 host.h_name = bp;
 418                                 nn = strlen(bp) + 1;    /* for the \0 */
 419                                 bp += nn;
 420                                 buflen -= nn;
 421                         }
 422
 423                         /* XXX: when incrementing bp, we have to decrement
 424                          * buflen by the same amount --okir */
 425                         buflen -= sizeof(align) - ((u_long)bp % sizeof(align));
 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_ninit(&_res) == -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_ninit(&_res) == -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_nsearch(&_res, name, C_IN, type, buf.buf, sizeof(buf.buf))) < 0) {
 617                 dprintf("res_nsearch 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 void *addr;
 628         socklen_t len;
 629         int af;
 630 {
 631         const u_char *uaddr = (const u_char *)addr;
 632         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 633         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 634         int n, size;
 635         querybuf buf;
 636         register struct hostent *hp;
 637         char qbuf[MAXDNAME+1], *qp;
 638 #ifdef SUNSECURITY
 639         register struct hostent *rhp;
 640         char **haddr;
 641         u_long old_options;
 642         char hname2[MAXDNAME+1];
 643 #endif /*SUNSECURITY*/
 644         extern struct hostent *_gethtbyaddr();
 645
 646         if ((_res.options & RES_INIT) == 0 && __res_ninit(&_res) == -1) {
 647                 __set_h_errno (NETDB_INTERNAL);
 648                 return (NULL);
 649         }
 650         if (af == AF_INET6 && len == IN6ADDRSZ &&
 651             (!bcmp(uaddr, mapped, sizeof mapped) ||
 652              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 653                 /* Unmap. */
 654                 addr += sizeof mapped;
 655                 uaddr += sizeof mapped;
 656                 af = AF_INET;
 657                 len = INADDRSZ;
 658         }
 659         switch (af) {
 660         case AF_INET:
 661                 size = INADDRSZ;
 662                 break;
 663         case AF_INET6:
 664                 size = IN6ADDRSZ;
 665                 break;
 666         default:
 667                 __set_errno (EAFNOSUPPORT);
 668                 __set_h_errno (NETDB_INTERNAL);
 669                 return (NULL);
 670         }
 671         if (size != len) {
 672                 __set_errno (EINVAL);
 673                 __set_h_errno (NETDB_INTERNAL);
 674                 return (NULL);
 675         }
 676         switch (af) {
 677         case AF_INET:
 678                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 679                                (uaddr[3] & 0xff),
 680                                (uaddr[2] & 0xff),
 681                                (uaddr[1] & 0xff),
 682                                (uaddr[0] & 0xff));
 683                 break;
 684         case AF_INET6:
 685                 qp = qbuf;
 686                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 687                         qp += SPRINTF((qp, "%x.%x.",
 688                                        uaddr[n] & 0xf,
 689                                        (uaddr[n] >> 4) & 0xf));
 690                 }
 691                 strcpy(qp, "ip6.int");
 692                 break;
 693         default:
 694                 abort();
 695         }
 696         n = res_nquery(&_res, qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
 697         if (n < 0) {
 698                 dprintf("res_nquery failed (%d)\n", n);
 699                 if (errno == ECONNREFUSED)
 700                         return (_gethtbyaddr(addr, len, af));
 701                 return (NULL);
 702         }
 703         if (!(hp = getanswer(&buf, n, qbuf, T_PTR)))
 704                 return (NULL);  /* h_errno was set by getanswer() */
 705 #ifdef SUNSECURITY
 706         if (af == AF_INET) {
 707             /*
 708              * turn off search as the name should be absolute,
 709              * 'localhost' should be matched by defnames
 710              */
 711             strncpy(hname2, hp->h_name, MAXDNAME);
 712             hname2[MAXDNAME] = '\0';
 713             old_options = _res.options;
 714             _res.options &= ~RES_DNSRCH;
 715             _res.options |= RES_DEFNAMES;
 716             if (!(rhp = gethostbyname(hname2))) {
 717                 syslog(LOG_NOTICE|LOG_AUTH,
 718                        "gethostbyaddr: No A record for %s (verifying [%s])",
 719                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 720                 _res.options = old_options;
 721                 __set_h_errno (HOST_NOT_FOUND);
 722                 return (NULL);
 723             }
 724             _res.options = old_options;
 725             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 726                 if (!memcmp(*haddr, addr, INADDRSZ))
 727                         break;
 728             if (!*haddr) {
 729                 syslog(LOG_NOTICE|LOG_AUTH,
 730                        "gethostbyaddr: A record of %s != PTR record [%s]",
 731                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 732                 __set_h_errno (HOST_NOT_FOUND);
 733                 return (NULL);
 734             }
 735         }
 736 #endif /*SUNSECURITY*/
 737         hp->h_addrtype = af;
 738         hp->h_length = len;
 739         bcopy(addr, host_addr, len);
 740         h_addr_ptrs[0] = (char *)host_addr;
 741         h_addr_ptrs[1] = NULL;
 742         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 743                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 744                 hp->h_addrtype = AF_INET6;
 745                 hp->h_length = IN6ADDRSZ;
 746         }
 747         __set_h_errno (NETDB_SUCCESS);
 748         return (hp);
 749 }
 750
 751 void
 752 _sethtent(f)
 753         int f;
 754 {
 755         if (!hostf)
 756                 hostf = fopen(_PATH_HOSTS, "r" );
 757         else
 758                 rewind(hostf);
 759         stayopen = f;
 760 }
 761
 762 void
 763 _endhtent()
 764 {
 765         if (hostf && !stayopen) {
 766                 (void) fclose(hostf);
 767                 hostf = NULL;
 768         }
 769 }
 770
 771 struct hostent *
 772 _gethtent()
 773 {
 774         char *p;
 775         register char *cp, **q;
 776         int af, len;
 777
 778         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
 779                 __set_h_errno (NETDB_INTERNAL);
 780                 return (NULL);
 781         }
 782  again:
 783         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 784                 __set_h_errno (HOST_NOT_FOUND);
 785                 return (NULL);
 786         }
 787         if (*p == '#')
 788                 goto again;
 789         if (!(cp = strpbrk(p, "#\n")))
 790                 goto again;
 791         *cp = '\0';
 792         if (!(cp = strpbrk(p, " \t")))
 793                 goto again;
 794         *cp++ = '\0';
 795         if (inet_pton(AF_INET6, p, host_addr) > 0) {
 796                 af = AF_INET6;
 797                 len = IN6ADDRSZ;
 798         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 799                 if (_res.options & RES_USE_INET6) {
 800                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 801                         af = AF_INET6;
 802                         len = IN6ADDRSZ;
 803                 } else {
 804                         af = AF_INET;
 805                         len = INADDRSZ;
 806                 }
 807         } else {
 808                 goto again;
 809         }
 810         h_addr_ptrs[0] = (char *)host_addr;
 811         h_addr_ptrs[1] = NULL;
 812         host.h_addr_list = h_addr_ptrs;
 813         host.h_length = len;
 814         host.h_addrtype = af;
 815         while (*cp == ' ' || *cp == '\t')
 816                 cp++;
 817         host.h_name = cp;
 818         q = host.h_aliases = host_aliases;
 819         if ((cp = strpbrk(cp, " \t")))
 820                 *cp++ = '\0';
 821         while (cp && *cp) {
 822                 if (*cp == ' ' || *cp == '\t') {
 823                         cp++;
 824                         continue;
 825                 }
 826                 if (q < &host_aliases[MAXALIASES - 1])
 827                         *q++ = cp;
 828                 if ((cp = strpbrk(cp, " \t")))
 829                         *cp++ = '\0';
 830         }
 831         *q = NULL;
 832         __set_h_errno (NETDB_SUCCESS);
 833         return (&host);
 834 }
 835
 836 struct hostent *
 837 _gethtbyname(name)
 838         const char *name;
 839 {
 840         extern struct hostent *_gethtbyname2();
 841         struct hostent *hp;
 842
 843         if (_res.options & RES_USE_INET6) {
 844                 hp = _gethtbyname2(name, AF_INET6);
 845                 if (hp)
 846                         return (hp);
 847         }
 848         return (_gethtbyname2(name, AF_INET));
 849 }
 850
 851 struct hostent *
 852 _gethtbyname2(name, af)
 853         const char *name;
 854         int af;
 855 {
 856         register struct hostent *p;
 857         register char **cp;
 858
 859         _sethtent(0);
 860         while ((p = _gethtent())) {
 861                 if (p->h_addrtype != af)
 862                         continue;
 863                 if (strcasecmp(p->h_name, name) == 0)
 864                         break;
 865                 for (cp = p->h_aliases; *cp != 0; cp++)
 866                         if (strcasecmp(*cp, name) == 0)
 867                                 goto found;
 868         }
 869  found:
 870         _endhtent();
 871         return (p);
 872 }
 873
 874 struct hostent *
 875 _gethtbyaddr(addr, len, af)
 876         const char *addr;
 877         size_t len;
 878         int af;
 879 {
 880         register struct hostent *p;
 881
 882         _sethtent(0);
 883         while ((p = _gethtent()))
 884                 if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
 885                         break;
 886         _endhtent();
 887         return (p);
 888 }
 889
 890 static void
 891 map_v4v6_address(src, dst)
 892         const char *src;
 893         char *dst;
 894 {
 895         u_char *p = (u_char *)dst;
 896         char tmp[INADDRSZ];
 897         int i;
 898
 899         /* Stash a temporary copy so our caller can update in place. */
 900         bcopy(src, tmp, INADDRSZ);
 901         /* Mark this ipv6 addr as a mapped ipv4. */
 902         for (i = 0; i < 10; i++)
 903                 *p++ = 0x00;
 904         *p++ = 0xff;
 905         *p++ = 0xff;
 906         /* Retrieve the saved copy and we're done. */
 907         bcopy(tmp, (void*)p, INADDRSZ);
 908 }
 909
 910 static void
 911 map_v4v6_hostent(hp, bpp, lenp)
 912         struct hostent *hp;
 913         char **bpp;
 914         int *lenp;
 915 {
 916         char **ap;
 917
 918         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 919                 return;
 920         hp->h_addrtype = AF_INET6;
 921         hp->h_length = IN6ADDRSZ;
 922         for (ap = hp->h_addr_list; *ap; ap++) {
 923                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 924
 925                 if (*lenp < (i + IN6ADDRSZ)) {
 926                         /* Out of memory.  Truncate address list here.  XXX */
 927                         *ap = NULL;
 928                         return;
 929                 }
 930                 *bpp += i;
 931                 *lenp -= i;
 932                 map_v4v6_address(*ap, *bpp);
 933                 *ap = *bpp;
 934                 *bpp += IN6ADDRSZ;
 935                 *lenp -= IN6ADDRSZ;
 936         }
 937 }
 938
 939 #ifdef RESOLVSORT
 940 extern void
 941 addrsort(ap, num)
 942         char **ap;
 943         int num;
 944 {
 945         int i, j;
 946         char **p;
 947         short aval[MAXADDRS];
 948         int needsort = 0;
 949
 950         p = ap;
 951         for (i = 0; i < num; i++, p++) {
 952             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 953                 if (_res.sort_list[j].addr.s_addr ==
 954                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 955                         break;
 956             aval[i] = j;
 957             if (needsort == 0 && i > 0 && j < aval[i-1])
 958                 needsort = i;
 959         }
 960         if (!needsort)
 961             return;
 962
 963         while (needsort < num) {
 964             for (j = needsort - 1; j >= 0; j--) {
 965                 if (aval[j] > aval[j+1]) {
 966                     char *hp;
 967
 968                     i = aval[j];
 969                     aval[j] = aval[j+1];
 970                     aval[j+1] = i;
 971
 972                     hp = ap[j];
 973                     ap[j] = ap[j+1];
 974                     ap[j+1] = hp;
 975
 976                 } else
 977                     break;
 978             }
 979             needsort++;
 980         }
 981 }
 982 #endif
 983
 984 #if defined(BSD43_BSD43_NFS) || defined(sun)
 985 /* some libc's out there are bound internally to these names (UMIPS) */
 986 void
 987 ht_sethostent(stayopen)
 988         int stayopen;
 989 {
 990         _sethtent(stayopen);
 991 }
 992
 993 void
 994 ht_endhostent()
 995 {
 996         _endhtent();
 997 }
 998
 999 struct hostent *
1000 ht_gethostbyname(name)
1001         char *name;
1002 {
1003         return (_gethtbyname(name));
1004 }
1005
1006 struct hostent *
1007 ht_gethostbyaddr(addr, len, af)
1008         const char *addr;
1009         size_t len;
1010         int af;
1011 {
1012         return (_gethtbyaddr(addr, len, af));
1013 }
1014
1015 struct hostent *
1016 gethostent()
1017 {
1018         return (_gethtent());
1019 }
1020
1021 void
1022 dns_service()
1023 {
1024         return;
1025 }
1026
1027 #undef dn_skipname
1028 dn_skipname(comp_dn, eom)
1029         const u_char *comp_dn, *eom;
1030 {
1031         return (__dn_skipname(comp_dn, eom));
1032 }
1033 #endif /*old-style libc with yp junk in it*/