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 (char *msg, 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 (const querybuf *answer, int anslen, const char *qname, int qtype)
 183 {
 184         const HEADER *hp;
 185         const u_char *cp;
 186         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) (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 != qtype) {
 333                         /* Log a low priority message if we get an unexpected
 334                          * record, but skip it if we are using DNSSEC since it
 335                          * uses many different types in responses that do not
 336                          * match QTYPE.
 337                          */
 338                         if ((_res.options & RES_USE_DNSSEC) == 0) {
 339                                 syslog(LOG_NOTICE|LOG_AUTH,
 340                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
 341                                         qname, p_class(C_IN), p_type(qtype),
 342                                         p_type(type));
 343                         }
 344                         cp += n;
 345                         continue;               /* XXX - had_error++ ? */
 346                 }
 347                 switch (type) {
 348                 case T_PTR:
 349                         if (strcasecmp(tname, bp) != 0) {
 350                                 syslog(LOG_NOTICE|LOG_AUTH,
 351                                        AskedForGot, qname, bp);
 352                                 cp += n;
 353                                 continue;       /* XXX - had_error++ ? */
 354                         }
 355                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 356                         if ((n < 0) || !res_hnok(bp)) {
 357                                 had_error++;
 358                                 break;
 359                         }
 360 #if MULTI_PTRS_ARE_ALIASES
 361                         cp += n;
 362                         if (cp != erdata) {
 363                                 __set_h_errno (NO_RECOVERY);
 364                                 return (NULL);
 365                         }
 366                         if (!haveanswer)
 367                                 host.h_name = bp;
 368                         else if (ap < &host_aliases[MAXALIASES-1])
 369                                 *ap++ = bp;
 370                         else
 371                                 n = -1;
 372                         if (n != -1) {
 373                                 n = strlen(bp) + 1;     /* for the \0 */
 374                                 if (n >= MAXHOSTNAMELEN) {
 375                                         had_error++;
 376                                         break;
 377                                 }
 378                                 bp += n;
 379                                 buflen -= n;
 380                         }
 381                         break;
 382 #else
 383                         host.h_name = bp;
 384                         if (_res.options & RES_USE_INET6) {
 385                                 n = strlen(bp) + 1;     /* for the \0 */
 386                                 if (n >= MAXHOSTNAMELEN) {
 387                                         had_error++;
 388                                         break;
 389                                 }
 390                                 bp += n;
 391                                 buflen -= n;
 392                                 map_v4v6_hostent(&host, &bp, &buflen);
 393                         }
 394                         __set_h_errno (NETDB_SUCCESS);
 395                         return (&host);
 396 #endif
 397                 case T_A:
 398                 case T_AAAA:
 399                         if (strcasecmp(host.h_name, bp) != 0) {
 400                                 syslog(LOG_NOTICE|LOG_AUTH,
 401                                        AskedForGot, host.h_name, bp);
 402                                 cp += n;
 403                                 continue;       /* XXX - had_error++ ? */
 404                         }
 405                         if (n != host.h_length) {
 406                                 cp += n;
 407                                 continue;
 408                         }
 409                         if (!haveanswer) {
 410                                 int nn;
 411
 412                                 host.h_name = bp;
 413                                 nn = strlen(bp) + 1;    /* for the \0 */
 414                                 bp += nn;
 415                                 buflen -= nn;
 416                         }
 417
 418                         /* XXX: when incrementing bp, we have to decrement
 419                          * buflen by the same amount --okir */
 420                         buflen -= sizeof(align) - ((u_long)bp % sizeof(align));
 421
 422                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 423
 424                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 425                                 Dprintf("size (%d) too big\n", n);
 426                                 had_error++;
 427                                 continue;
 428                         }
 429                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 430                                 if (!toobig++) {
 431                                         Dprintf("Too many addresses (%d)\n",
 432                                                 MAXADDRS);
 433                                 }
 434                                 cp += n;
 435                                 continue;
 436                         }
 437                         memmove(*hap++ = bp, cp, n);
 438                         bp += n;
 439                         buflen -= n;
 440                         cp += n;
 441                         if (cp != erdata) {
 442                                 __set_h_errno (NO_RECOVERY);
 443                                 return (NULL);
 444                         }
 445                         break;
 446                 default:
 447                         abort();
 448                 }
 449                 if (!had_error)
 450                         haveanswer++;
 451         }
 452         if (haveanswer) {
 453                 *ap = NULL;
 454                 *hap = NULL;
 455 # if defined(RESOLVSORT)
 456                 /*
 457                  * Note: we sort even if host can take only one address
 458                  * in its return structures - should give it the "best"
 459                  * address in that case, not some random one
 460                  */
 461                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 462                         addrsort(h_addr_ptrs, haveanswer);
 463 # endif /*RESOLVSORT*/
 464                 if (!host.h_name) {
 465                         n = strlen(qname) + 1;  /* for the \0 */
 466                         if (n > buflen || n >= MAXHOSTNAMELEN)
 467                                 goto no_recovery;
 468                         strcpy(bp, qname);
 469                         host.h_name = bp;
 470                         bp += n;
 471                         buflen -= n;
 472                 }
 473                 if (_res.options & RES_USE_INET6)
 474                         map_v4v6_hostent(&host, &bp, &buflen);
 475                 __set_h_errno (NETDB_SUCCESS);
 476                 return (&host);
 477         }
 478  no_recovery:
 479         __set_h_errno (NO_RECOVERY);
 480         return (NULL);
 481 }
 482
 483 extern struct hostent *gethostbyname2(const char *name, int af);
 484 libresolv_hidden_proto (gethostbyname2)
 485
 486 struct hostent *
 487 gethostbyname (const char *name)
 488 {
 489         struct hostent *hp;
 490
 491         if (__res_maybe_init (&_res, 0) == -1) {
 492                 __set_h_errno (NETDB_INTERNAL);
 493                 return (NULL);
 494         }
 495         if (_res.options & RES_USE_INET6) {
 496                 hp = gethostbyname2(name, AF_INET6);
 497                 if (hp)
 498                         return (hp);
 499         }
 500         return (gethostbyname2(name, AF_INET));
 501 }
 502
 503 struct hostent *
 504 gethostbyname2 (const char *name, int af)
 505 {
 506         union
 507         {
 508           querybuf *buf;
 509           u_char *ptr;
 510         } buf;
 511         querybuf *origbuf;
 512         const char *cp;
 513         char *bp;
 514         int n, size, type, len;
 515         struct hostent *ret;
 516
 517         if (__res_maybe_init (&_res, 0) == -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         buf.buf = origbuf = (querybuf *) alloca (1024);
 617
 618         if ((n = __libc_res_nsearch(&_res, name, C_IN, type, buf.buf->buf, 1024,
 619                                     &buf.ptr, NULL, NULL, NULL, NULL)) < 0) {
 620                 if (buf.buf != origbuf)
 621                         free (buf.buf);
 622                 Dprintf("res_nsearch failed (%d)\n", n);
 623                 if (errno == ECONNREFUSED)
 624                         return (_gethtbyname2(name, af));
 625                 return (NULL);
 626         }
 627         ret = getanswer(buf.buf, n, name, type);
 628         if (buf.buf != origbuf)
 629                 free (buf.buf);
 630         return ret;
 631 }
 632 libresolv_hidden_def (gethostbyname2)
 633
 634 struct hostent *
 635 gethostbyaddr (const void *addr, socklen_t len, int af)
 636 {
 637         const u_char *uaddr = (const u_char *)addr;
 638         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 639         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 640         int n;
 641         socklen_t size;
 642         union
 643         {
 644           querybuf *buf;
 645           u_char *ptr;
 646         } buf;
 647         querybuf *orig_buf;
 648         struct hostent *hp;
 649         char qbuf[MAXDNAME+1], *qp = NULL;
 650 #ifdef SUNSECURITY
 651         struct hostent *rhp;
 652         char **haddr;
 653         u_long old_options;
 654         char hname2[MAXDNAME+1];
 655 #endif /*SUNSECURITY*/
 656
 657         if (__res_maybe_init (&_res, 0) == -1) {
 658                 __set_h_errno (NETDB_INTERNAL);
 659                 return (NULL);
 660         }
 661         if (af == AF_INET6 && len == IN6ADDRSZ &&
 662             (!memcmp(uaddr, mapped, sizeof mapped) ||
 663              !memcmp(uaddr, tunnelled, sizeof tunnelled))) {
 664                 /* Unmap. */
 665                 addr += sizeof mapped;
 666                 uaddr += sizeof mapped;
 667                 af = AF_INET;
 668                 len = INADDRSZ;
 669         }
 670         switch (af) {
 671         case AF_INET:
 672                 size = INADDRSZ;
 673                 break;
 674         case AF_INET6:
 675                 size = IN6ADDRSZ;
 676                 break;
 677         default:
 678                 __set_errno (EAFNOSUPPORT);
 679                 __set_h_errno (NETDB_INTERNAL);
 680                 return (NULL);
 681         }
 682         if (size != len) {
 683                 __set_errno (EINVAL);
 684                 __set_h_errno (NETDB_INTERNAL);
 685                 return (NULL);
 686         }
 687         switch (af) {
 688         case AF_INET:
 689                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 690                                (uaddr[3] & 0xff),
 691                                (uaddr[2] & 0xff),
 692                                (uaddr[1] & 0xff),
 693                                (uaddr[0] & 0xff));
 694                 break;
 695         case AF_INET6:
 696                 qp = qbuf;
 697                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 698                         qp += SPRINTF((qp, "%x.%x.",
 699                                        uaddr[n] & 0xf,
 700                                        (uaddr[n] >> 4) & 0xf));
 701                 }
 702                 strcpy(qp, "ip6.arpa");
 703                 break;
 704         default:
 705                 abort();
 706         }
 707
 708         buf.buf = orig_buf = (querybuf *) alloca (1024);
 709
 710         n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf, 1024,
 711                               &buf.ptr, NULL, NULL, NULL, NULL);
 712         if (n < 0 && af == AF_INET6 && (_res.options & RES_NOIP6DOTINT) == 0) {
 713                 strcpy(qp, "ip6.int");
 714                 n = __libc_res_nquery(&_res, qbuf, C_IN, T_PTR, buf.buf->buf,
 715                                       buf.buf != orig_buf ? MAXPACKET : 1024,
 716                                       &buf.ptr, NULL, NULL, NULL, NULL);
 717         }
 718         if (n < 0) {
 719                 if (buf.buf != orig_buf)
 720                         free (buf.buf);
 721                 Dprintf("res_nquery failed (%d)\n", n);
 722                 if (errno == ECONNREFUSED)
 723                         return (_gethtbyaddr(addr, len, af));
 724                 return (NULL);
 725         }
 726         hp = getanswer(buf.buf, n, qbuf, T_PTR);
 727         if (buf.buf != orig_buf)
 728                 free (buf.buf);
 729         if (!hp)
 730                 return (NULL);  /* h_errno was set by getanswer() */
 731 #ifdef SUNSECURITY
 732         if (af == AF_INET) {
 733             /*
 734              * turn off search as the name should be absolute,
 735              * 'localhost' should be matched by defnames
 736              */
 737             strncpy(hname2, hp->h_name, MAXDNAME);
 738             hname2[MAXDNAME] = '\0';
 739             old_options = _res.options;
 740             _res.options &= ~RES_DNSRCH;
 741             _res.options |= RES_DEFNAMES;
 742             if (!(rhp = gethostbyname(hname2))) {
 743                 syslog(LOG_NOTICE|LOG_AUTH,
 744                        "gethostbyaddr: No A record for %s (verifying [%s])",
 745                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 746                 _res.options = old_options;
 747                 __set_h_errno (HOST_NOT_FOUND);
 748                 return (NULL);
 749             }
 750             _res.options = old_options;
 751             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 752                 if (!memcmp(*haddr, addr, INADDRSZ))
 753                         break;
 754             if (!*haddr) {
 755                 syslog(LOG_NOTICE|LOG_AUTH,
 756                        "gethostbyaddr: A record of %s != PTR record [%s]",
 757                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 758                 __set_h_errno (HOST_NOT_FOUND);
 759                 return (NULL);
 760             }
 761         }
 762 #endif /*SUNSECURITY*/
 763         hp->h_addrtype = af;
 764         hp->h_length = len;
 765         memmove(host_addr, addr, len);
 766         h_addr_ptrs[0] = (char *)host_addr;
 767         h_addr_ptrs[1] = NULL;
 768         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 769                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 770                 hp->h_addrtype = AF_INET6;
 771                 hp->h_length = IN6ADDRSZ;
 772         }
 773         __set_h_errno (NETDB_SUCCESS);
 774         return (hp);
 775 }
 776
 777 void
 778 _sethtent (int f)
 779 {
 780         if (!hostf)
 781                 hostf = fopen(_PATH_HOSTS, "rce" );
 782         else
 783                 rewind(hostf);
 784         stayopen = f;
 785 }
 786 libresolv_hidden_def (_sethtent)
 787
 788 void
 789 _endhtent (void)
 790 {
 791         if (hostf && !stayopen) {
 792                 (void) fclose(hostf);
 793                 hostf = NULL;
 794         }
 795 }
 796
 797 struct hostent *
 798 _gethtent (void)
 799 {
 800         char *p;
 801         char *cp, **q;
 802         int af, len;
 803
 804         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "rce" ))) {
 805                 __set_h_errno (NETDB_INTERNAL);
 806                 return (NULL);
 807         }
 808  again:
 809         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 810                 __set_h_errno (HOST_NOT_FOUND);
 811                 return (NULL);
 812         }
 813         if (*p == '#')
 814                 goto again;
 815         if (!(cp = strpbrk(p, "#\n")))
 816                 goto again;
 817         *cp = '\0';
 818         if (!(cp = strpbrk(p, " \t")))
 819                 goto again;
 820         *cp++ = '\0';
 821         if (inet_pton(AF_INET6, p, host_addr) > 0) {
 822                 af = AF_INET6;
 823                 len = IN6ADDRSZ;
 824         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 825                 if (_res.options & RES_USE_INET6) {
 826                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 827                         af = AF_INET6;
 828                         len = IN6ADDRSZ;
 829                 } else {
 830                         af = AF_INET;
 831                         len = INADDRSZ;
 832                 }
 833         } else {
 834                 goto again;
 835         }
 836         h_addr_ptrs[0] = (char *)host_addr;
 837         h_addr_ptrs[1] = NULL;
 838         host.h_addr_list = h_addr_ptrs;
 839         host.h_length = len;
 840         host.h_addrtype = af;
 841         while (*cp == ' ' || *cp == '\t')
 842                 cp++;
 843         host.h_name = cp;
 844         q = host.h_aliases = host_aliases;
 845         if ((cp = strpbrk(cp, " \t")))
 846                 *cp++ = '\0';
 847         while (cp && *cp) {
 848                 if (*cp == ' ' || *cp == '\t') {
 849                         cp++;
 850                         continue;
 851                 }
 852                 if (q < &host_aliases[MAXALIASES - 1])
 853                         *q++ = cp;
 854                 if ((cp = strpbrk(cp, " \t")))
 855                         *cp++ = '\0';
 856         }
 857         *q = NULL;
 858         __set_h_errno (NETDB_SUCCESS);
 859         return (&host);
 860 }
 861 libresolv_hidden_def (_gethtent)
 862
 863 struct hostent *
 864 _gethtbyname (const char *name)
 865 {
 866         struct hostent *hp;
 867
 868         if (_res.options & RES_USE_INET6) {
 869                 hp = _gethtbyname2(name, AF_INET6);
 870                 if (hp)
 871                         return (hp);
 872         }
 873         return (_gethtbyname2(name, AF_INET));
 874 }
 875
 876 struct hostent *
 877 _gethtbyname2 (const char *name, int af)
 878 {
 879         struct hostent *p;
 880         char **cp;
 881
 882         _sethtent(0);
 883         while ((p = _gethtent())) {
 884                 if (p->h_addrtype != af)
 885                         continue;
 886                 if (strcasecmp(p->h_name, name) == 0)
 887                         break;
 888                 for (cp = p->h_aliases; *cp != 0; cp++)
 889                         if (strcasecmp(*cp, name) == 0)
 890                                 goto found;
 891         }
 892  found:
 893         _endhtent();
 894         return (p);
 895 }
 896 libresolv_hidden_def (_gethtbyname2)
 897
 898 struct hostent *
 899 _gethtbyaddr (const char *addr, size_t len, int af)
 900 {
 901         struct hostent *p;
 902
 903         _sethtent(0);
 904         while ((p = _gethtent()))
 905                 if (p->h_addrtype == af && !memcmp(p->h_addr, addr, len))
 906                         break;
 907         _endhtent();
 908         return (p);
 909 }
 910 libresolv_hidden_def (_gethtbyaddr)
 911
 912 static void
 913 map_v4v6_address (const char *src, char *dst)
 914 {
 915         u_char *p = (u_char *)dst;
 916         char tmp[INADDRSZ];
 917         int i;
 918
 919         /* Stash a temporary copy so our caller can update in place. */
 920         memcpy(tmp, src, INADDRSZ);
 921         /* Mark this ipv6 addr as a mapped ipv4. */
 922         for (i = 0; i < 10; i++)
 923                 *p++ = 0x00;
 924         *p++ = 0xff;
 925         *p++ = 0xff;
 926         /* Retrieve the saved copy and we're done. */
 927         memcpy((void*)p, tmp, INADDRSZ);
 928 }
 929
 930 static void
 931 map_v4v6_hostent (struct hostent *hp, char **bpp, int *lenp)
 932 {
 933         char **ap;
 934
 935         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 936                 return;
 937         hp->h_addrtype = AF_INET6;
 938         hp->h_length = IN6ADDRSZ;
 939         for (ap = hp->h_addr_list; *ap; ap++) {
 940                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 941
 942                 if (*lenp < (i + IN6ADDRSZ)) {
 943                         /* Out of memory.  Truncate address list here.  XXX */
 944                         *ap = NULL;
 945                         return;
 946                 }
 947                 *bpp += i;
 948                 *lenp -= i;
 949                 map_v4v6_address(*ap, *bpp);
 950                 *ap = *bpp;
 951                 *bpp += IN6ADDRSZ;
 952                 *lenp -= IN6ADDRSZ;
 953         }
 954 }
 955
 956 #ifdef RESOLVSORT
 957 extern void
 958 addrsort (char **ap, int num)
 959 {
 960         int i, j;
 961         char **p;
 962         short aval[MAXADDRS];
 963         int needsort = 0;
 964
 965         p = ap;
 966         for (i = 0; i < num; i++, p++) {
 967             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 968                 if (_res.sort_list[j].addr.s_addr ==
 969                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 970                         break;
 971             aval[i] = j;
 972             if (needsort == 0 && i > 0 && j < aval[i-1])
 973                 needsort = i;
 974         }
 975         if (!needsort)
 976             return;
 977
 978         while (needsort < num) {
 979             for (j = needsort - 1; j >= 0; j--) {
 980                 if (aval[j] > aval[j+1]) {
 981                     char *hp;
 982
 983                     i = aval[j];
 984                     aval[j] = aval[j+1];
 985                     aval[j+1] = i;
 986
 987                     hp = ap[j];
 988                     ap[j] = ap[j+1];
 989                     ap[j+1] = hp;
 990
 991                 } else
 992                     break;
 993             }
 994             needsort++;
 995         }
 996 }
 997 #endif
 998
 999 #if defined(BSD43_BSD43_NFS) || defined(sun)
1000 /* some libc's out there are bound internally to these names (UMIPS) */
1001 void
1002 ht_sethostent (int stayopen)
1003 {
1004         _sethtent(stayopen);
1005 }
1006
1007 void
1008 ht_endhostent (void)
1009 {
1010         _endhtent();
1011 }
1012
1013 struct hostent *
1014 ht_gethostbyname (char *name)
1015 {
1016         return (_gethtbyname(name));
1017 }
1018
1019 struct hostent *
1020 ht_gethostbyaddr (const char *addr, size_t len, int af)
1021 {
1022         return (_gethtbyaddr(addr, len, af));
1023 }
1024
1025 struct hostent *
1026 gethostent (void)
1027 {
1028         return (_gethtent());
1029 }
1030
1031 void
1032 dns_service (void)
1033 {
1034         return;
1035 }
1036
1037 #undef dn_skipname
1038 dn_skipname(comp_dn, eom)
1039         const u_char *comp_dn, *eom;
1040 {
1041         return (__dn_skipname(comp_dn, eom));
1042 }
1043 #endif /*old-style libc with yp junk in it*/