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 /* XXX This file is not used by any of the resolver functions implemented by
  53    glibc (i.e. get*info and gethostby*).  It cannot be removed however because
  54    it exports symbols in the libresolv ABI.  The file is not maintained any
  55    more, nor are these functions.  */
  56
  57 #if defined(LIBC_SCCS) && !defined(lint)
  58 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
  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 #define RESOLVSORT
  76
  77 #ifndef LOG_AUTH
  78 # define LOG_AUTH 0
  79 #endif
  80
  81 #define MULTI_PTRS_ARE_ALIASES 1        /* XXX - experimental */
  82
  83 #if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
  84 # include <stdlib.h>
  85 # include <string.h>
  86 #else
  87 # include "../conf/portability.h"
  88 #endif
  89
  90 #if defined(USE_OPTIONS_H)
  91 # include <../conf/options.h>
  92 #endif
  93
  94 #ifdef SPRINTF_CHAR
  95 # define SPRINTF(x) strlen(sprintf/**/x)
  96 #else
  97 # define SPRINTF(x) ((size_t)sprintf x)
  98 #endif
  99
 100 #define MAXALIASES      35
 101 #define MAXADDRS        35
 102
 103 static const char AskedForGot[] =
 104                           "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
 105
 106 static char *h_addr_ptrs[MAXADDRS + 1];
 107
 108 static struct hostent host;
 109 static char *host_aliases[MAXALIASES];
 110 static char hostbuf[8*1024];
 111 static u_char host_addr[16];    /* IPv4 or IPv6 */
 112 static FILE *hostf = NULL;
 113 static int stayopen = 0;
 114
 115 static void map_v4v6_address (const char *src, char *dst) __THROW;
 116 static void map_v4v6_hostent (struct hostent *hp, char **bp, int *len) __THROW;
 117
 118 #ifdef RESOLVSORT
 119 extern void addrsort (char **, int) __THROW;
 120 #endif
 121
 122 #if PACKETSZ > 65536
 123 #define MAXPACKET       PACKETSZ
 124 #else
 125 #define MAXPACKET       65536
 126 #endif
 127
 128 /* As per RFC 1034 and 1035 a host name cannot exceed 255 octets in length.  */
 129 #ifdef MAXHOSTNAMELEN
 130 # undef MAXHOSTNAMELEN
 131 #endif
 132 #define MAXHOSTNAMELEN 256
 133
 134 typedef union {
 135     HEADER hdr;
 136     u_char buf[MAXPACKET];
 137 } querybuf;
 138
 139 typedef union {
 140     int32_t al;
 141     char ac;
 142 } align;
 143
 144 #ifndef h_errno
 145 extern int h_errno;
 146 #endif
 147
 148 #ifdef DEBUG
 149 static void
 150 Dprintf(msg, num)
 151         char *msg;
 152         int num;
 153 {
 154         if (_res.options & RES_DEBUG) {
 155                 int save = errno;
 156
 157                 printf(msg, num);
 158                 __set_errno (save);
 159         }
 160 }
 161 #else
 162 # define Dprintf(msg, num) /*nada*/
 163 #endif
 164
 165 #define BOUNDED_INCR(x) \
 166         do { \
 167                 cp += x; \
 168                 if (cp > eom) { \
 169                         __set_h_errno (NO_RECOVERY); \
 170                         return (NULL); \
 171                 } \
 172         } while (0)
 173
 174 #define BOUNDS_CHECK(ptr, count) \
 175         do { \
 176                 if ((ptr) + (count) > eom) { \
 177                         __set_h_errno (NO_RECOVERY); \
 178                         return (NULL); \
 179                 } \
 180         } while (0)
 181
 182
 183 static struct hostent *
 184 getanswer (const querybuf *answer, int anslen, const char *qname, int qtype)
 185 {
 186         const HEADER *hp;
 187         const u_char *cp;
 188         int n;
 189         const u_char *eom, *erdata;
 190         char *bp, **ap, **hap;
 191         int type, class, buflen, ancount, qdcount;
 192         int haveanswer, had_error;
 193         int toobig = 0;
 194         char tbuf[MAXDNAME];
 195         const char *tname;
 196         int (*name_ok) (const char *);
 197
 198         tname = qname;
 199         host.h_name = NULL;
 200         eom = answer->buf + anslen;
 201         switch (qtype) {
 202         case T_A:
 203         case T_AAAA:
 204                 name_ok = res_hnok;
 205                 break;
 206         case T_PTR:
 207                 name_ok = res_dnok;
 208                 break;
 209         default:
 210                 return (NULL);  /* XXX should be abort(); */
 211         }
 212         /*
 213          * find first satisfactory answer
 214          */
 215         hp = &answer->hdr;
 216         ancount = ntohs(hp->ancount);
 217         qdcount = ntohs(hp->qdcount);
 218         bp = hostbuf;
 219         buflen = sizeof hostbuf;
 220         cp = answer->buf;
 221         BOUNDED_INCR(HFIXEDSZ);
 222         if (qdcount != 1) {
 223                 __set_h_errno (NO_RECOVERY);
 224                 return (NULL);
 225         }
 226         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 227         if ((n < 0) || !(*name_ok)(bp)) {
 228                 __set_h_errno (NO_RECOVERY);
 229                 return (NULL);
 230         }
 231         BOUNDED_INCR(n + QFIXEDSZ);
 232         if (qtype == T_A || qtype == T_AAAA) {
 233                 /* res_send() has already verified that the query name is the
 234                  * same as the one we sent; this just gets the expanded name
 235                  * (i.e., with the succeeding search-domain tacked on).
 236                  */
 237                 n = strlen(bp) + 1;             /* for the \0 */
 238                 if (n >= MAXHOSTNAMELEN) {
 239                         __set_h_errno (NO_RECOVERY);
 240                         return (NULL);
 241                 }
 242                 host.h_name = bp;
 243                 bp += n;
 244                 buflen -= n;
 245                 /* The qname can be abbreviated, but h_name is now absolute. */
 246                 qname = host.h_name;
 247         }
 248         ap = host_aliases;
 249         *ap = NULL;
 250         host.h_aliases = host_aliases;
 251         hap = h_addr_ptrs;
 252         *hap = NULL;
 253         host.h_addr_list = h_addr_ptrs;
 254         haveanswer = 0;
 255         had_error = 0;
 256         while (ancount-- > 0 && cp < eom && !had_error) {
 257                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 258                 if ((n < 0) || !(*name_ok)(bp)) {
 259                         had_error++;
 260                         continue;
 261                 }
 262                 cp += n;                        /* name */
 263                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 264                 type = ns_get16(cp);
 265                 cp += INT16SZ;                  /* type */
 266                 class = ns_get16(cp);
 267                 cp += INT16SZ + INT32SZ;        /* class, TTL */
 268                 n = ns_get16(cp);
 269                 cp += INT16SZ;                  /* len */
 270                 BOUNDS_CHECK(cp, n);
 271                 erdata = cp + n;
 272                 if (class != C_IN) {
 273                         /* XXX - debug? syslog? */
 274                         cp += n;
 275                         continue;               /* XXX - had_error++ ? */
 276                 }
 277                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 278                         if (ap >= &host_aliases[MAXALIASES-1])
 279                                 continue;
 280                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 281                         if ((n < 0) || !(*name_ok)(tbuf)) {
 282                                 had_error++;
 283                                 continue;
 284                         }
 285                         cp += n;
 286                         if (cp != erdata) {
 287                                 __set_h_errno (NO_RECOVERY);
 288                                 return (NULL);
 289                         }
 290                         /* Store alias. */
 291                         *ap++ = bp;
 292                         n = strlen(bp) + 1;     /* for the \0 */
 293                         if (n >= MAXHOSTNAMELEN) {
 294                                 had_error++;
 295                                 continue;
 296                         }
 297                         bp += n;
 298                         buflen -= n;
 299                         /* Get canonical name. */
 300                         n = strlen(tbuf) + 1;   /* for the \0 */
 301                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 302                                 had_error++;
 303                                 continue;
 304                         }
 305                         strcpy(bp, tbuf);
 306                         host.h_name = bp;
 307                         bp += n;
 308                         buflen -= n;
 309                         continue;
 310                 }
 311                 if (qtype == T_PTR && type == T_CNAME) {
 312                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 313                         if (n < 0 || !res_dnok(tbuf)) {
 314                                 had_error++;
 315                                 continue;
 316                         }
 317                         cp += n;
 318                         if (cp != erdata) {
 319                                 __set_h_errno (NO_RECOVERY);
 320                                 return (NULL);
 321                         }
 322                         /* Get canonical name. */
 323                         n = strlen(tbuf) + 1;   /* for the \0 */
 324                         if (n > buflen || n >= MAXHOSTNAMELEN) {
 325                                 had_error++;
 326                                 continue;
 327                         }
 328                         strcpy(bp, tbuf);
 329                         tname = bp;
 330                         bp += n;
 331                         buflen -= n;
 332                         continue;
 333                 }
 334                 if (type != qtype) {
 335                         /* Log a low priority message if we get an unexpected
 336                          * record, but skip it if we are using DNSSEC since it
 337                          * uses many different types in responses that do not
 338                          * match QTYPE.
 339                          */
 340                         if ((_res.options & RES_USE_DNSSEC) == 0) {
 341                                 syslog(LOG_NOTICE|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                         }
 346                         cp += n;
 347                         continue;               /* XXX - had_error++ ? */
 348                 }
 349                 switch (type) {
 350                 case T_PTR:
 351                         if (strcasecmp(tname, bp) != 0) {
 352                                 syslog(LOG_NOTICE|LOG_AUTH,
 353                                        AskedForGot, qname, bp);
 354                                 cp += n;
 355                                 continue;       /* XXX - had_error++ ? */
 356                         }
 357                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 358                         if ((n < 0) || !res_hnok(bp)) {
 359                                 had_error++;
 360                                 break;
 361                         }
 362 #if MULTI_PTRS_ARE_ALIASES
 363                         cp += n;
 364                         if (cp != erdata) {
 365                                 __set_h_errno (NO_RECOVERY);
 366                                 return (NULL);
 367                         }
 368                         if (!haveanswer)
 369                                 host.h_name = bp;
 370                         else if (ap < &host_aliases[MAXALIASES-1])
 371                                 *ap++ = bp;
 372                         else
 373                                 n = -1;
 374                         if (n != -1) {
 375                                 n = strlen(bp) + 1;     /* for the \0 */
 376                                 if (n >= MAXHOSTNAMELEN) {
 377                                         had_error++;
 378                                         break;
 379                                 }
 380                                 bp += n;
 381                                 buflen -= n;
 382                         }
 383                         break;
 384 #else
 385                         host.h_name = bp;
 386                         if (_res.options & RES_USE_INET6) {
 387                                 n = strlen(bp) + 1;     /* for the \0 */
 388                                 if (n >= MAXHOSTNAMELEN) {
 389                                         had_error++;
 390                                         break;
 391                                 }
 392                                 bp += n;
 393                                 buflen -= n;
 394                                 map_v4v6_hostent(&host, &bp, &buflen);
 395                         }
 396                         __set_h_errno (NETDB_SUCCESS);
 397                         return (&host);
 398 #endif
 399                 case T_A:
 400                 case T_AAAA:
 401                         if (strcasecmp(host.h_name, bp) != 0) {
 402                                 syslog(LOG_NOTICE|LOG_AUTH,
 403                                        AskedForGot, host.h_name, bp);
 404                                 cp += n;
 405                                 continue;       /* XXX - had_error++ ? */
 406                         }
 407                         if (n != host.h_length) {
 408                                 cp += n;
 409                                 continue;
 410                         }
 411                         if (!haveanswer) {
 412                                 int nn;
 413
 414                                 host.h_name = bp;
 415                                 nn = strlen(bp) + 1;    /* for the \0 */
 416                                 bp += nn;
 417                                 buflen -= nn;
 418                         }
 419
 420                         /* XXX: when incrementing bp, we have to decrement
 421                          * buflen by the same amount --okir */
 422                         buflen -= sizeof(align) - ((u_long)bp % sizeof(align));
 423
 424                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 425
 426                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 427                                 Dprintf("size (%d) too big\n", n);
 428                                 had_error++;
 429                                 continue;
 430                         }
 431                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 432                                 if (!toobig++) {
 433                                         Dprintf("Too many addresses (%d)\n",
 434                                                 MAXADDRS);
 435                                 }
 436                                 cp += n;
 437                                 continue;
 438                         }
 439                         memmove(*hap++ = bp, cp, n);
 440                         bp += n;
 441                         buflen -= n;
 442                         cp += n;
 443                         if (cp != erdata) {
 444                                 __set_h_errno (NO_RECOVERY);
 445                                 return (NULL);
 446                         }
 447                         break;
 448                 default:
 449                         abort();
 450                 }
 451                 if (!had_error)
 452                         haveanswer++;
 453         }
 454         if (haveanswer) {
 455                 *ap = NULL;
 456                 *hap = NULL;
 457 # if defined(RESOLVSORT)
 458                 /*
 459                  * Note: we sort even if host can take only one address
 460                  * in its return structures - should give it the "best"
 461                  * address in that case, not some random one
 462                  */
 463                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 464                         addrsort(h_addr_ptrs, haveanswer);
 465 # endif /*RESOLVSORT*/
 466                 if (!host.h_name) {
 467                         n = strlen(qname) + 1;  /* for the \0 */
 468                         if (n > buflen || n >= MAXHOSTNAMELEN)
 469                                 goto no_recovery;
 470                         strcpy(bp, qname);
 471                         host.h_name = bp;
 472                         bp += n;
 473                         buflen -= n;
 474                 }
 475                 if (_res.options & RES_USE_INET6)
 476                         map_v4v6_hostent(&host, &bp, &buflen);
 477                 __set_h_errno (NETDB_SUCCESS);
 478                 return (&host);
 479         }
 480  no_recovery:
 481         __set_h_errno (NO_RECOVERY);
 482         return (NULL);
 483 }
 484
 485 extern struct hostent *gethostbyname2(const char *name, int af);
 486 libresolv_hidden_proto (gethostbyname2)
 487
 488 struct hostent *
 489 gethostbyname(name)
 490         const char *name;
 491 {
 492         struct hostent *hp;
 493
 494         if (__res_maybe_init (&_res, 0) == -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         union
 512         {
 513           querybuf *buf;
 514           u_char *ptr;
 515         } buf;
 516         querybuf *origbuf;
 517         const char *cp;
 518         char *bp;
 519         int n, size, type, len;
 520         struct hostent *ret;
 521
 522         if (__res_maybe_init (&_res, 0) == -1) {
 523                 __set_h_errno (NETDB_INTERNAL);
 524                 return (NULL);
 525         }
 526
 527         switch (af) {
 528         case AF_INET:
 529                 size = INADDRSZ;
 530                 type = T_A;
 531                 break;
 532         case AF_INET6:
 533                 size = IN6ADDRSZ;
 534                 type = T_AAAA;
 535                 break;
 536         default:
 537                 __set_h_errno (NETDB_INTERNAL);
 538                 __set_errno (EAFNOSUPPORT);
 539                 return (NULL);
 540         }
 541
 542         host.h_addrtype = af;
 543         host.h_length = size;
 544
 545         /*
 546          * if there aren't any dots, it could be a user-level alias.
 547          * this is also done in res_query() since we are not the only
 548          * function that looks up host names.
 549          */
 550         if (!strchr(name, '.') && (cp = __hostalias(name)))
 551                 name = cp;
 552
 553         /*
 554          * disallow names consisting only of digits/dots, unless
 555          * they end in a dot.
 556          */
 557         if (isdigit(name[0]))
 558                 for (cp = name;; ++cp) {
 559                         if (!*cp) {
 560                                 if (*--cp == '.')
 561                                         break;
 562                                 /*
 563                                  * All-numeric, no dot at the end.
 564                                  * Fake up a hostent as if we'd actually
 565                                  * done a lookup.
 566                                  */
 567                                 if (inet_pton(af, name, host_addr) <= 0) {
 568                                         __set_h_errno (HOST_NOT_FOUND);
 569                                         return (NULL);
 570                                 }
 571                                 strncpy(hostbuf, name, MAXDNAME);
 572                                 hostbuf[MAXDNAME] = '\0';
 573                                 bp = hostbuf + MAXDNAME;
 574                                 len = sizeof hostbuf - MAXDNAME;
 575                                 host.h_name = hostbuf;
 576                                 host.h_aliases = host_aliases;
 577                                 host_aliases[0] = NULL;
 578                                 h_addr_ptrs[0] = (char *)host_addr;
 579                                 h_addr_ptrs[1] = NULL;
 580                                 host.h_addr_list = h_addr_ptrs;
 581                                 if (_res.options & RES_USE_INET6)
 582                                         map_v4v6_hostent(&host, &bp, &len);
 583                                 __set_h_errno (NETDB_SUCCESS);
 584                                 return (&host);
 585                         }
 586                         if (!isdigit(*cp) && *cp != '.')
 587                                 break;
 588                }
 589         if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
 590             name[0] == ':')
 591                 for (cp = name;; ++cp) {
 592                         if (!*cp) {
 593                                 if (*--cp == '.')
 594                                         break;
 595                                 /*
 596                                  * All-IPv6-legal, no dot at the end.
 597                                  * Fake up a hostent as if we'd actually
 598                                  * done a lookup.
 599                                  */
 600                                 if (inet_pton(af, name, host_addr) <= 0) {
 601                                         __set_h_errno (HOST_NOT_FOUND);
 602                                         return (NULL);
 603                                 }
 604                                 strncpy(hostbuf, name, MAXDNAME);
 605                                 hostbuf[MAXDNAME] = '\0';
 606                                 bp = hostbuf + MAXDNAME;
 607                                 len = sizeof hostbuf - MAXDNAME;
 608                                 host.h_name = hostbuf;
 609                                 host.h_aliases = host_aliases;
 610                                 host_aliases[0] = NULL;
 611                                 h_addr_ptrs[0] = (char *)host_addr;
 612                                 h_addr_ptrs[1] = NULL;
 613                                 host.h_addr_list = h_addr_ptrs;
 614                                 __set_h_errno (NETDB_SUCCESS);
 615                                 return (&host);
 616                         }
 617                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
 618                                 break;
 619                 }
 620
 621         buf.buf = origbuf = (querybuf *) alloca (1024);
 622
 623         if ((n = __libc_res_nsearch(&_res, name, C_IN, type, buf.buf->buf, 1024,
 624                                     &buf.ptr, NULL, NULL, NULL, NULL)) < 0) {
 625                 if (buf.buf != origbuf)
 626                         free (buf.buf);
 627                 Dprintf("res_nsearch failed (%d)\n", n);
 628                 if (errno == ECONNREFUSED)
 629                         return (_gethtbyname2(name, af));
 630                 return (NULL);
 631         }
 632         ret = getanswer(buf.buf, n, name, type);
 633         if (buf.buf != origbuf)
 634                 free (buf.buf);
 635         return ret;
 636 }
 637 libresolv_hidden_def (gethostbyname2)
 638
 639 struct hostent *
 640 gethostbyaddr(addr, len, af)
 641         const void *addr;
 642         socklen_t len;
 643         int af;
 644 {
 645         const u_char *uaddr = (const u_char *)addr;
 646         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 647         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 648         int n;
 649         socklen_t size;
 650         union
 651         {
 652           querybuf *buf;
 653           u_char *ptr;
 654         } buf;
 655         querybuf *orig_buf;
 656         struct hostent *hp;
 657         char qbuf[MAXDNAME+1], *qp = NULL;
 658 #ifdef SUNSECURITY
 659         struct hostent *rhp;
 660         char **haddr;
 661         u_long old_options;
 662         char hname2[MAXDNAME+1];
 663 #endif /*SUNSECURITY*/
 664
 665         if (__res_maybe_init (&_res, 0) == -1) {
 666                 __set_h_errno (NETDB_INTERNAL);
 667                 return (NULL);
 668         }
 669         if (af == AF_INET6 && len == IN6ADDRSZ &&
 670             (!memcmp(uaddr, mapped, sizeof mapped) ||
 671              !memcmp(uaddr, tunnelled, sizeof tunnelled))) {
 672                 /* Unmap. */
 673                 addr += sizeof mapped;
 674                 uaddr += sizeof mapped;
 675                 af = AF_INET;
 676                 len = INADDRSZ;
 677         }
 678         switch (af) {
 679         case AF_INET:
 680                 size = INADDRSZ;
 681                 break;
 682         case AF_INET6:
 683                 size = IN6ADDRSZ;
 684                 break;
 685         default:
 686                 __set_errno (EAFNOSUPPORT);
 687                 __set_h_errno (NETDB_INTERNAL);
 688                 return (NULL);
 689         }
 690         if (size != len) {
 691                 __set_errno (EINVAL);
 692                 __set_h_errno (NETDB_INTERNAL);
 693                 return (NULL);
 694         }
 695         switch (af) {
 696         case AF_INET:
 697                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 698                                (uaddr[3] & 0xff),
 699                                (uaddr[2] & 0xff),
 700                                (uaddr[1] & 0xff),
 701                                (uaddr[0] & 0xff));
 702                 break;
 703         case AF_INET6:
 704                 qp = qbuf;
 705                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 706                         qp += SPRINTF((qp, "%x.%x.",
 707                                        uaddr[n] & 0xf,
 708                                        (uaddr[n] >> 4) & 0xf));
 709                 }
 710                 strcpy(qp, "ip6.arpa");
 711                 break;
 712         default:
 713                 abort();
 714         }
 715
 716         buf.buf = orig_buf = (querybuf *) alloca (1024);
 717
 718         n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf, 1024,
 719                               &buf.ptr, NULL, NULL, NULL, NULL);
 720         if (n < 0 && af == AF_INET6 && (_res.options & RES_NOIP6DOTINT) == 0) {
 721                 strcpy(qp, "ip6.int");
 722                 n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf,
 723                                       buf.buf != orig_buf ? MAXPACKET : 1024,
 724                                       &buf.ptr, NULL, NULL, NULL, NULL);
 725         }
 726         if (n < 0) {
 727                 if (buf.buf != orig_buf)
 728                         free (buf.buf);
 729                 Dprintf("res_nquery failed (%d)\n", n);
 730                 if (errno == ECONNREFUSED)
 731                         return (_gethtbyaddr(addr, len, af));
 732                 return (NULL);
 733         }
 734         hp = getanswer(buf.buf, n, qbuf, T_PTR);
 735         if (buf.buf != orig_buf)
 736                 free (buf.buf);
 737         if (!hp)
 738                 return (NULL);  /* h_errno was set by getanswer() */
 739 #ifdef SUNSECURITY
 740         if (af == AF_INET) {
 741             /*
 742              * turn off search as the name should be absolute,
 743              * 'localhost' should be matched by defnames
 744              */
 745             strncpy(hname2, hp->h_name, MAXDNAME);
 746             hname2[MAXDNAME] = '\0';
 747             old_options = _res.options;
 748             _res.options &= ~RES_DNSRCH;
 749             _res.options |= RES_DEFNAMES;
 750             if (!(rhp = gethostbyname(hname2))) {
 751                 syslog(LOG_NOTICE|LOG_AUTH,
 752                        "gethostbyaddr: No A record for %s (verifying [%s])",
 753                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 754                 _res.options = old_options;
 755                 __set_h_errno (HOST_NOT_FOUND);
 756                 return (NULL);
 757             }
 758             _res.options = old_options;
 759             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 760                 if (!memcmp(*haddr, addr, INADDRSZ))
 761                         break;
 762             if (!*haddr) {
 763                 syslog(LOG_NOTICE|LOG_AUTH,
 764                        "gethostbyaddr: A record of %s != PTR record [%s]",
 765                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 766                 __set_h_errno (HOST_NOT_FOUND);
 767                 return (NULL);
 768             }
 769         }
 770 #endif /*SUNSECURITY*/
 771         hp->h_addrtype = af;
 772         hp->h_length = len;
 773         memmove(host_addr, addr, len);
 774         h_addr_ptrs[0] = (char *)host_addr;
 775         h_addr_ptrs[1] = NULL;
 776         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 777                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 778                 hp->h_addrtype = AF_INET6;
 779                 hp->h_length = IN6ADDRSZ;
 780         }
 781         __set_h_errno (NETDB_SUCCESS);
 782         return (hp);
 783 }
 784
 785 void
 786 _sethtent(f)
 787         int f;
 788 {
 789         if (!hostf)
 790                 hostf = fopen(_PATH_HOSTS, "rce" );
 791         else
 792                 rewind(hostf);
 793         stayopen = f;
 794 }
 795 libresolv_hidden_def (_sethtent)
 796
 797 void
 798 _endhtent (void)
 799 {
 800         if (hostf && !stayopen) {
 801                 (void) fclose(hostf);
 802                 hostf = NULL;
 803         }
 804 }
 805
 806 struct hostent *
 807 _gethtent (void)
 808 {
 809         char *p;
 810         char *cp, **q;
 811         int af, len;
 812
 813         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "rce" ))) {
 814                 __set_h_errno (NETDB_INTERNAL);
 815                 return (NULL);
 816         }
 817  again:
 818         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 819                 __set_h_errno (HOST_NOT_FOUND);
 820                 return (NULL);
 821         }
 822         if (*p == '#')
 823                 goto again;
 824         if (!(cp = strpbrk(p, "#\n")))
 825                 goto again;
 826         *cp = '\0';
 827         if (!(cp = strpbrk(p, " \t")))
 828                 goto again;
 829         *cp++ = '\0';
 830         if (inet_pton(AF_INET6, p, host_addr) > 0) {
 831                 af = AF_INET6;
 832                 len = IN6ADDRSZ;
 833         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 834                 if (_res.options & RES_USE_INET6) {
 835                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 836                         af = AF_INET6;
 837                         len = IN6ADDRSZ;
 838                 } else {
 839                         af = AF_INET;
 840                         len = INADDRSZ;
 841                 }
 842         } else {
 843                 goto again;
 844         }
 845         h_addr_ptrs[0] = (char *)host_addr;
 846         h_addr_ptrs[1] = NULL;
 847         host.h_addr_list = h_addr_ptrs;
 848         host.h_length = len;
 849         host.h_addrtype = af;
 850         while (*cp == ' ' || *cp == '\t')
 851                 cp++;
 852         host.h_name = cp;
 853         q = host.h_aliases = host_aliases;
 854         if ((cp = strpbrk(cp, " \t")))
 855                 *cp++ = '\0';
 856         while (cp && *cp) {
 857                 if (*cp == ' ' || *cp == '\t') {
 858                         cp++;
 859                         continue;
 860                 }
 861                 if (q < &host_aliases[MAXALIASES - 1])
 862                         *q++ = cp;
 863                 if ((cp = strpbrk(cp, " \t")))
 864                         *cp++ = '\0';
 865         }
 866         *q = NULL;
 867         __set_h_errno (NETDB_SUCCESS);
 868         return (&host);
 869 }
 870 libresolv_hidden_def (_gethtent)
 871
 872 struct hostent *
 873 _gethtbyname(name)
 874         const char *name;
 875 {
 876         struct hostent *hp;
 877
 878         if (_res.options & RES_USE_INET6) {
 879                 hp = _gethtbyname2(name, AF_INET6);
 880                 if (hp)
 881                         return (hp);
 882         }
 883         return (_gethtbyname2(name, AF_INET));
 884 }
 885
 886 struct hostent *
 887 _gethtbyname2(name, af)
 888         const char *name;
 889         int af;
 890 {
 891         struct hostent *p;
 892         char **cp;
 893
 894         _sethtent(0);
 895         while ((p = _gethtent())) {
 896                 if (p->h_addrtype != af)
 897                         continue;
 898                 if (strcasecmp(p->h_name, name) == 0)
 899                         break;
 900                 for (cp = p->h_aliases; *cp != 0; cp++)
 901                         if (strcasecmp(*cp, name) == 0)
 902                                 goto found;
 903         }
 904  found:
 905         _endhtent();
 906         return (p);
 907 }
 908 libresolv_hidden_def (_gethtbyname2)
 909
 910 struct hostent *
 911 _gethtbyaddr(addr, len, af)
 912         const char *addr;
 913         size_t len;
 914         int af;
 915 {
 916         struct hostent *p;
 917
 918         _sethtent(0);
 919         while ((p = _gethtent()))
 920                 if (p->h_addrtype == af && !memcmp(p->h_addr, addr, len))
 921                         break;
 922         _endhtent();
 923         return (p);
 924 }
 925 libresolv_hidden_def (_gethtbyaddr)
 926
 927 static void
 928 map_v4v6_address(src, dst)
 929         const char *src;
 930         char *dst;
 931 {
 932         u_char *p = (u_char *)dst;
 933         char tmp[INADDRSZ];
 934         int i;
 935
 936         /* Stash a temporary copy so our caller can update in place. */
 937         memcpy(tmp, src, INADDRSZ);
 938         /* Mark this ipv6 addr as a mapped ipv4. */
 939         for (i = 0; i < 10; i++)
 940                 *p++ = 0x00;
 941         *p++ = 0xff;
 942         *p++ = 0xff;
 943         /* Retrieve the saved copy and we're done. */
 944         memcpy((void*)p, tmp, INADDRSZ);
 945 }
 946
 947 static void
 948 map_v4v6_hostent(hp, bpp, lenp)
 949         struct hostent *hp;
 950         char **bpp;
 951         int *lenp;
 952 {
 953         char **ap;
 954
 955         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 956                 return;
 957         hp->h_addrtype = AF_INET6;
 958         hp->h_length = IN6ADDRSZ;
 959         for (ap = hp->h_addr_list; *ap; ap++) {
 960                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 961
 962                 if (*lenp < (i + IN6ADDRSZ)) {
 963                         /* Out of memory.  Truncate address list here.  XXX */
 964                         *ap = NULL;
 965                         return;
 966                 }
 967                 *bpp += i;
 968                 *lenp -= i;
 969                 map_v4v6_address(*ap, *bpp);
 970                 *ap = *bpp;
 971                 *bpp += IN6ADDRSZ;
 972                 *lenp -= IN6ADDRSZ;
 973         }
 974 }
 975
 976 #ifdef RESOLVSORT
 977 extern void
 978 addrsort(ap, num)
 979         char **ap;
 980         int num;
 981 {
 982         int i, j;
 983         char **p;
 984         short aval[MAXADDRS];
 985         int needsort = 0;
 986
 987         p = ap;
 988         for (i = 0; i < num; i++, p++) {
 989             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 990                 if (_res.sort_list[j].addr.s_addr ==
 991                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 992                         break;
 993             aval[i] = j;
 994             if (needsort == 0 && i > 0 && j < aval[i-1])
 995                 needsort = i;
 996         }
 997         if (!needsort)
 998             return;
 999
1000         while (needsort < num) {
1001             for (j = needsort - 1; j >= 0; j--) {
1002                 if (aval[j] > aval[j+1]) {
1003                     char *hp;
1004
1005                     i = aval[j];
1006                     aval[j] = aval[j+1];
1007                     aval[j+1] = i;
1008
1009                     hp = ap[j];
1010                     ap[j] = ap[j+1];
1011                     ap[j+1] = hp;
1012
1013                 } else
1014                     break;
1015             }
1016             needsort++;
1017         }
1018 }
1019 #endif
1020
1021 #if defined(BSD43_BSD43_NFS) || defined(sun)
1022 /* some libc's out there are bound internally to these names (UMIPS) */
1023 void
1024 ht_sethostent(stayopen)
1025         int stayopen;
1026 {
1027         _sethtent(stayopen);
1028 }
1029
1030 void
1031 ht_endhostent (void)
1032 {
1033         _endhtent();
1034 }
1035
1036 struct hostent *
1037 ht_gethostbyname(name)
1038         char *name;
1039 {
1040         return (_gethtbyname(name));
1041 }
1042
1043 struct hostent *
1044 ht_gethostbyaddr(addr, len, af)
1045         const char *addr;
1046         size_t len;
1047         int af;
1048 {
1049         return (_gethtbyaddr(addr, len, af));
1050 }
1051
1052 struct hostent *
1053 gethostent (void)
1054 {
1055         return (_gethtent());
1056 }
1057
1058 void
1059 dns_service (void)
1060 {
1061         return;
1062 }
1063
1064 #undef dn_skipname
1065 dn_skipname(comp_dn, eom)
1066         const u_char *comp_dn, *eom;
1067 {
1068         return (__dn_skipname(comp_dn, eom));
1069 }
1070 #endif /*old-style libc with yp junk in it*/