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 = _getshort(cp);
 263                 cp += INT16SZ;                  /* type */
 264                 class = _getshort(cp);
 265                 cp += INT16SZ + INT32SZ;        /* class, TTL */
 266                 n = _getshort(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                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 424
 425                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
 426                                 dprintf("size (%d) too big\n", n);
 427                                 had_error++;
 428                                 continue;
 429                         }
 430                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 431                                 if (!toobig++) {
 432                                         dprintf("Too many addresses (%d)\n",
 433                                                 MAXADDRS);
 434                                 }
 435                                 cp += n;
 436                                 continue;
 437                         }
 438                         bcopy(cp, *hap++ = bp, n);
 439                         bp += n;
 440                         buflen -= n;
 441                         cp += n;
 442                         if (cp != erdata) {
 443                                 __set_h_errno (NO_RECOVERY);
 444                                 return (NULL);
 445                         }
 446                         break;
 447                 default:
 448                         abort();
 449                 }
 450                 if (!had_error)
 451                         haveanswer++;
 452         }
 453         if (haveanswer) {
 454                 *ap = NULL;
 455                 *hap = NULL;
 456 # if defined(RESOLVSORT)
 457                 /*
 458                  * Note: we sort even if host can take only one address
 459                  * in its return structures - should give it the "best"
 460                  * address in that case, not some random one
 461                  */
 462                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
 463                         addrsort(h_addr_ptrs, haveanswer);
 464 # endif /*RESOLVSORT*/
 465                 if (!host.h_name) {
 466                         n = strlen(qname) + 1;  /* for the \0 */
 467                         if (n > buflen || n >= MAXHOSTNAMELEN)
 468                                 goto no_recovery;
 469                         strcpy(bp, qname);
 470                         host.h_name = bp;
 471                         bp += n;
 472                         buflen -= n;
 473                 }
 474                 if (_res.options & RES_USE_INET6)
 475                         map_v4v6_hostent(&host, &bp, &buflen);
 476                 __set_h_errno (NETDB_SUCCESS);
 477                 return (&host);
 478         }
 479  no_recovery:
 480         __set_h_errno (NO_RECOVERY);
 481         return (NULL);
 482 }
 483
 484 struct hostent *
 485 gethostbyname(name)
 486         const char *name;
 487 {
 488         struct hostent *hp;
 489
 490         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 491                 __set_h_errno (NETDB_INTERNAL);
 492                 return (NULL);
 493        }
 494         if (_res.options & RES_USE_INET6) {
 495                 hp = gethostbyname2(name, AF_INET6);
 496                 if (hp)
 497                         return (hp);
 498         }
 499         return (gethostbyname2(name, AF_INET));
 500 }
 501
 502 struct hostent *
 503 gethostbyname2(name, af)
 504         const char *name;
 505         int af;
 506 {
 507         querybuf buf;
 508         register const char *cp;
 509         char *bp;
 510         int n, size, type, len;
 511         extern struct hostent *_gethtbyname2();
 512
 513         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 514                 __set_h_errno (NETDB_INTERNAL);
 515                 return (NULL);
 516         }
 517
 518         switch (af) {
 519         case AF_INET:
 520                 size = INADDRSZ;
 521                 type = T_A;
 522                 break;
 523         case AF_INET6:
 524                 size = IN6ADDRSZ;
 525                 type = T_AAAA;
 526                 break;
 527         default:
 528                 __set_h_errno (NETDB_INTERNAL);
 529                 __set_errno (EAFNOSUPPORT);
 530                 return (NULL);
 531         }
 532
 533         host.h_addrtype = af;
 534         host.h_length = size;
 535
 536         /*
 537          * if there aren't any dots, it could be a user-level alias.
 538          * this is also done in res_query() since we are not the only
 539          * function that looks up host names.
 540          */
 541         if (!strchr(name, '.') && (cp = __hostalias(name)))
 542                 name = cp;
 543
 544         /*
 545          * disallow names consisting only of digits/dots, unless
 546          * they end in a dot.
 547          */
 548         if (isdigit(name[0]))
 549                 for (cp = name;; ++cp) {
 550                         if (!*cp) {
 551                                 if (*--cp == '.')
 552                                         break;
 553                                 /*
 554                                  * All-numeric, no dot at the end.
 555                                  * Fake up a hostent as if we'd actually
 556                                  * done a lookup.
 557                                  */
 558                                 if (inet_pton(af, name, host_addr) <= 0) {
 559                                         __set_h_errno (HOST_NOT_FOUND);
 560                                         return (NULL);
 561                                 }
 562                                 strncpy(hostbuf, name, MAXDNAME);
 563                                 hostbuf[MAXDNAME] = '\0';
 564                                 bp = hostbuf + MAXDNAME;
 565                                 len = sizeof hostbuf - MAXDNAME;
 566                                 host.h_name = hostbuf;
 567                                 host.h_aliases = host_aliases;
 568                                 host_aliases[0] = NULL;
 569                                 h_addr_ptrs[0] = (char *)host_addr;
 570                                 h_addr_ptrs[1] = NULL;
 571                                 host.h_addr_list = h_addr_ptrs;
 572                                 if (_res.options & RES_USE_INET6)
 573                                         map_v4v6_hostent(&host, &bp, &len);
 574                                 __set_h_errno (NETDB_SUCCESS);
 575                                 return (&host);
 576                         }
 577                         if (!isdigit(*cp) && *cp != '.')
 578                                 break;
 579                }
 580         if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
 581             name[0] == ':')
 582                 for (cp = name;; ++cp) {
 583                         if (!*cp) {
 584                                 if (*--cp == '.')
 585                                         break;
 586                                 /*
 587                                  * All-IPv6-legal, no dot at the end.
 588                                  * Fake up a hostent as if we'd actually
 589                                  * done a lookup.
 590                                  */
 591                                 if (inet_pton(af, name, host_addr) <= 0) {
 592                                         __set_h_errno (HOST_NOT_FOUND);
 593                                         return (NULL);
 594                                 }
 595                                 strncpy(hostbuf, name, MAXDNAME);
 596                                 hostbuf[MAXDNAME] = '\0';
 597                                 bp = hostbuf + MAXDNAME;
 598                                 len = sizeof hostbuf - MAXDNAME;
 599                                 host.h_name = hostbuf;
 600                                 host.h_aliases = host_aliases;
 601                                 host_aliases[0] = NULL;
 602                                 h_addr_ptrs[0] = (char *)host_addr;
 603                                 h_addr_ptrs[1] = NULL;
 604                                 host.h_addr_list = h_addr_ptrs;
 605                                 __set_h_errno (NETDB_SUCCESS);
 606                                 return (&host);
 607                         }
 608                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
 609                                 break;
 610                 }
 611
 612         if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf.buf))) < 0) {
 613                 dprintf("res_search failed (%d)\n", n);
 614                 if (errno == ECONNREFUSED)
 615                         return (_gethtbyname2(name, af));
 616                 return (NULL);
 617         }
 618         return (getanswer(&buf, n, name, type));
 619 }
 620
 621 struct hostent *
 622 gethostbyaddr(addr, len, af)
 623         const char *addr;       /* XXX should have been def'd as u_char! */
 624         size_t len;
 625         int af;
 626 {
 627         const u_char *uaddr = (const u_char *)addr;
 628         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 629         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 630         int n, size;
 631         querybuf buf;
 632         register struct hostent *hp;
 633         char qbuf[MAXDNAME+1], *qp;
 634 #ifdef SUNSECURITY
 635         register struct hostent *rhp;
 636         char **haddr;
 637         u_long old_options;
 638         char hname2[MAXDNAME+1];
 639 #endif /*SUNSECURITY*/
 640         extern struct hostent *_gethtbyaddr();
 641
 642         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 643                 __set_h_errno (NETDB_INTERNAL);
 644                 return (NULL);
 645         }
 646         if (af == AF_INET6 && len == IN6ADDRSZ &&
 647             (!bcmp(uaddr, mapped, sizeof mapped) ||
 648              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
 649                 /* Unmap. */
 650                 addr += sizeof mapped;
 651                 uaddr += sizeof mapped;
 652                 af = AF_INET;
 653                 len = INADDRSZ;
 654         }
 655         switch (af) {
 656         case AF_INET:
 657                 size = INADDRSZ;
 658                 break;
 659         case AF_INET6:
 660                 size = IN6ADDRSZ;
 661                 break;
 662         default:
 663                 __set_errno (EAFNOSUPPORT);
 664                 __set_h_errno (NETDB_INTERNAL);
 665                 return (NULL);
 666         }
 667         if (size != len) {
 668                 __set_errno (EINVAL);
 669                 __set_h_errno (NETDB_INTERNAL);
 670                 return (NULL);
 671         }
 672         switch (af) {
 673         case AF_INET:
 674                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 675                                (uaddr[3] & 0xff),
 676                                (uaddr[2] & 0xff),
 677                                (uaddr[1] & 0xff),
 678                                (uaddr[0] & 0xff));
 679                 break;
 680         case AF_INET6:
 681                 qp = qbuf;
 682                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 683                         qp += SPRINTF((qp, "%x.%x.",
 684                                        uaddr[n] & 0xf,
 685                                        (uaddr[n] >> 4) & 0xf));
 686                 }
 687                 strcpy(qp, "ip6.int");
 688                 break;
 689         default:
 690                 abort();
 691         }
 692         n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
 693         if (n < 0) {
 694                 dprintf("res_query failed (%d)\n", n);
 695                 if (errno == ECONNREFUSED)
 696                         return (_gethtbyaddr(addr, len, af));
 697                 return (NULL);
 698         }
 699         if (!(hp = getanswer(&buf, n, qbuf, T_PTR)))
 700                 return (NULL);  /* h_errno was set by getanswer() */
 701 #ifdef SUNSECURITY
 702         if (af == AF_INET) {
 703             /*
 704              * turn off search as the name should be absolute,
 705              * 'localhost' should be matched by defnames
 706              */
 707             strncpy(hname2, hp->h_name, MAXDNAME);
 708             hname2[MAXDNAME] = '\0';
 709             old_options = _res.options;
 710             _res.options &= ~RES_DNSRCH;
 711             _res.options |= RES_DEFNAMES;
 712             if (!(rhp = gethostbyname(hname2))) {
 713                 syslog(LOG_NOTICE|LOG_AUTH,
 714                        "gethostbyaddr: No A record for %s (verifying [%s])",
 715                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 716                 _res.options = old_options;
 717                 __set_h_errno (HOST_NOT_FOUND);
 718                 return (NULL);
 719             }
 720             _res.options = old_options;
 721             for (haddr = rhp->h_addr_list; *haddr; haddr++)
 722                 if (!memcmp(*haddr, addr, INADDRSZ))
 723                         break;
 724             if (!*haddr) {
 725                 syslog(LOG_NOTICE|LOG_AUTH,
 726                        "gethostbyaddr: A record of %s != PTR record [%s]",
 727                        hname2, inet_ntoa(*((struct in_addr *)addr)));
 728                 __set_h_errno (HOST_NOT_FOUND);
 729                 return (NULL);
 730             }
 731         }
 732 #endif /*SUNSECURITY*/
 733         hp->h_addrtype = af;
 734         hp->h_length = len;
 735         bcopy(addr, host_addr, len);
 736         h_addr_ptrs[0] = (char *)host_addr;
 737         h_addr_ptrs[1] = NULL;
 738         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
 739                 map_v4v6_address((char*)host_addr, (char*)host_addr);
 740                 hp->h_addrtype = AF_INET6;
 741                 hp->h_length = IN6ADDRSZ;
 742         }
 743         __set_h_errno (NETDB_SUCCESS);
 744         return (hp);
 745 }
 746
 747 void
 748 _sethtent(f)
 749         int f;
 750 {
 751         if (!hostf)
 752                 hostf = fopen(_PATH_HOSTS, "r" );
 753         else
 754                 rewind(hostf);
 755         stayopen = f;
 756 }
 757
 758 void
 759 _endhtent()
 760 {
 761         if (hostf && !stayopen) {
 762                 (void) fclose(hostf);
 763                 hostf = NULL;
 764         }
 765 }
 766
 767 struct hostent *
 768 _gethtent()
 769 {
 770         char *p;
 771         register char *cp, **q;
 772         int af, len;
 773
 774         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
 775                 __set_h_errno (NETDB_INTERNAL);
 776                 return (NULL);
 777         }
 778  again:
 779         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
 780                 __set_h_errno (HOST_NOT_FOUND);
 781                 return (NULL);
 782         }
 783         if (*p == '#')
 784                 goto again;
 785         if (!(cp = strpbrk(p, "#\n")))
 786                 goto again;
 787         *cp = '\0';
 788         if (!(cp = strpbrk(p, " \t")))
 789                 goto again;
 790         *cp++ = '\0';
 791         if (inet_pton(AF_INET6, p, host_addr) > 0) {
 792                 af = AF_INET6;
 793                 len = IN6ADDRSZ;
 794         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
 795                 if (_res.options & RES_USE_INET6) {
 796                         map_v4v6_address((char*)host_addr, (char*)host_addr);
 797                         af = AF_INET6;
 798                         len = IN6ADDRSZ;
 799                 } else {
 800                         af = AF_INET;
 801                         len = INADDRSZ;
 802                 }
 803         } else {
 804                 goto again;
 805         }
 806         h_addr_ptrs[0] = (char *)host_addr;
 807         h_addr_ptrs[1] = NULL;
 808         host.h_addr_list = h_addr_ptrs;
 809         host.h_length = len;
 810         host.h_addrtype = af;
 811         while (*cp == ' ' || *cp == '\t')
 812                 cp++;
 813         host.h_name = cp;
 814         q = host.h_aliases = host_aliases;
 815         if ((cp = strpbrk(cp, " \t")))
 816                 *cp++ = '\0';
 817         while (cp && *cp) {
 818                 if (*cp == ' ' || *cp == '\t') {
 819                         cp++;
 820                         continue;
 821                 }
 822                 if (q < &host_aliases[MAXALIASES - 1])
 823                         *q++ = cp;
 824                 if ((cp = strpbrk(cp, " \t")))
 825                         *cp++ = '\0';
 826         }
 827         *q = NULL;
 828         __set_h_errno (NETDB_SUCCESS);
 829         return (&host);
 830 }
 831
 832 struct hostent *
 833 _gethtbyname(name)
 834         const char *name;
 835 {
 836         extern struct hostent *_gethtbyname2();
 837         struct hostent *hp;
 838
 839         if (_res.options & RES_USE_INET6) {
 840                 hp = _gethtbyname2(name, AF_INET6);
 841                 if (hp)
 842                         return (hp);
 843         }
 844         return (_gethtbyname2(name, AF_INET));
 845 }
 846
 847 struct hostent *
 848 _gethtbyname2(name, af)
 849         const char *name;
 850         int af;
 851 {
 852         register struct hostent *p;
 853         register char **cp;
 854
 855         _sethtent(0);
 856         while ((p = _gethtent())) {
 857                 if (p->h_addrtype != af)
 858                         continue;
 859                 if (strcasecmp(p->h_name, name) == 0)
 860                         break;
 861                 for (cp = p->h_aliases; *cp != 0; cp++)
 862                         if (strcasecmp(*cp, name) == 0)
 863                                 goto found;
 864         }
 865  found:
 866         _endhtent();
 867         return (p);
 868 }
 869
 870 struct hostent *
 871 _gethtbyaddr(addr, len, af)
 872         const char *addr;
 873         size_t len;
 874         int af;
 875 {
 876         register struct hostent *p;
 877
 878         _sethtent(0);
 879         while ((p = _gethtent()))
 880                 if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
 881                         break;
 882         _endhtent();
 883         return (p);
 884 }
 885
 886 static void
 887 map_v4v6_address(src, dst)
 888         const char *src;
 889         char *dst;
 890 {
 891         u_char *p = (u_char *)dst;
 892         char tmp[INADDRSZ];
 893         int i;
 894
 895         /* Stash a temporary copy so our caller can update in place. */
 896         bcopy(src, tmp, INADDRSZ);
 897         /* Mark this ipv6 addr as a mapped ipv4. */
 898         for (i = 0; i < 10; i++)
 899                 *p++ = 0x00;
 900         *p++ = 0xff;
 901         *p++ = 0xff;
 902         /* Retrieve the saved copy and we're done. */
 903         bcopy(tmp, (void*)p, INADDRSZ);
 904 }
 905
 906 static void
 907 map_v4v6_hostent(hp, bpp, lenp)
 908         struct hostent *hp;
 909         char **bpp;
 910         int *lenp;
 911 {
 912         char **ap;
 913
 914         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
 915                 return;
 916         hp->h_addrtype = AF_INET6;
 917         hp->h_length = IN6ADDRSZ;
 918         for (ap = hp->h_addr_list; *ap; ap++) {
 919                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
 920
 921                 if (*lenp < (i + IN6ADDRSZ)) {
 922                         /* Out of memory.  Truncate address list here.  XXX */
 923                         *ap = NULL;
 924                         return;
 925                 }
 926                 *bpp += i;
 927                 *lenp -= i;
 928                 map_v4v6_address(*ap, *bpp);
 929                 *ap = *bpp;
 930                 *bpp += IN6ADDRSZ;
 931                 *lenp -= IN6ADDRSZ;
 932         }
 933 }
 934
 935 #ifdef RESOLVSORT
 936 extern void
 937 addrsort(ap, num)
 938         char **ap;
 939         int num;
 940 {
 941         int i, j;
 942         char **p;
 943         short aval[MAXADDRS];
 944         int needsort = 0;
 945
 946         p = ap;
 947         for (i = 0; i < num; i++, p++) {
 948             for (j = 0 ; (unsigned)j < _res.nsort; j++)
 949                 if (_res.sort_list[j].addr.s_addr ==
 950                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
 951                         break;
 952             aval[i] = j;
 953             if (needsort == 0 && i > 0 && j < aval[i-1])
 954                 needsort = i;
 955         }
 956         if (!needsort)
 957             return;
 958
 959         while (needsort < num) {
 960             for (j = needsort - 1; j >= 0; j--) {
 961                 if (aval[j] > aval[j+1]) {
 962                     char *hp;
 963
 964                     i = aval[j];
 965                     aval[j] = aval[j+1];
 966                     aval[j+1] = i;
 967
 968                     hp = ap[j];
 969                     ap[j] = ap[j+1];
 970                     ap[j+1] = hp;
 971
 972                 } else
 973                     break;
 974             }
 975             needsort++;
 976         }
 977 }
 978 #endif
 979
 980 #if defined(BSD43_BSD43_NFS) || defined(sun)
 981 /* some libc's out there are bound internally to these names (UMIPS) */
 982 void
 983 ht_sethostent(stayopen)
 984         int stayopen;
 985 {
 986         _sethtent(stayopen);
 987 }
 988
 989 void
 990 ht_endhostent()
 991 {
 992         _endhtent();
 993 }
 994
 995 struct hostent *
 996 ht_gethostbyname(name)
 997         char *name;
 998 {
 999         return (_gethtbyname(name));
1000 }
1001
1002 struct hostent *
1003 ht_gethostbyaddr(addr, len, af)
1004         const char *addr;
1005         size_t len;
1006         int af;
1007 {
1008         return (_gethtbyaddr(addr, len, af));
1009 }
1010
1011 struct hostent *
1012 gethostent()
1013 {
1014         return (_gethtent());
1015 }
1016
1017 void
1018 dns_service()
1019 {
1020         return;
1021 }
1022
1023 #undef dn_skipname
1024 dn_skipname(comp_dn, eom)
1025         const u_char *comp_dn, *eom;
1026 {
1027         return (__dn_skipname(comp_dn, eom));
1028 }
1029 #endif /*old-style libc with yp junk in it*/