update from main archive 961001
[kopensolaris-gnu/glibc.git] / resolv / gethnamaddr.c
1 /*
2  * ++Copyright++ 1985, 1988, 1993
3  * -
4  * Copyright (c) 1985, 1988, 1993
5  *    The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *      This product includes software developed by the University of
18  *      California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  * -
35  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
36  *
37  * Permission to use, copy, modify, and distribute this software for any
38  * purpose with or without fee is hereby granted, provided that the above
39  * copyright notice and this permission notice appear in all copies, and that
40  * the name of Digital Equipment Corporation not be used in advertising or
41  * publicity pertaining to distribution of the document or software without
42  * specific, written prior permission.
43  *
44  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
45  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
46  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
47  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
48  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
49  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
50  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
51  * SOFTWARE.
52  * -
53  * --Copyright--
54  */
55
56 #if defined(LIBC_SCCS) && !defined(lint)
57 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
58 static char rcsid[] = "$Id$";
59 #endif /* LIBC_SCCS and not lint */
60
61 #include <sys/types.h>
62 #include <sys/param.h>
63 #include <sys/socket.h>
64 #include <netinet/in.h>
65 #include <arpa/inet.h>
66 #include <arpa/nameser.h>
67
68 #include <stdio.h>
69 #include <netdb.h>
70 #include <resolv.h>
71 #include <ctype.h>
72 #include <errno.h>
73 #include <syslog.h>
74
75 #ifndef LOG_AUTH
76 # define LOG_AUTH 0
77 #endif
78
79 #define MULTI_PTRS_ARE_ALIASES 1        /* XXX - experimental */
80
81 #if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
82 # include <stdlib.h>
83 # include <string.h>
84 #else
85 # include "../conf/portability.h"
86 #endif
87
88 #if defined(USE_OPTIONS_H)
89 # include <../conf/options.h>
90 #endif
91
92 #ifdef SPRINTF_CHAR
93 # define SPRINTF(x) strlen(sprintf/**/x)
94 #else
95 # define SPRINTF(x) ((size_t)sprintf x)
96 #endif
97
98 #define MAXALIASES      35
99 #define MAXADDRS        35
100
101 static const char AskedForGot[] =
102                           "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
103
104 static char *h_addr_ptrs[MAXADDRS + 1];
105
106 static struct hostent host;
107 static char *host_aliases[MAXALIASES];
108 static char hostbuf[8*1024];
109 static u_char host_addr[16];    /* IPv4 or IPv6 */
110 static FILE *hostf = NULL;
111 static int stayopen = 0;
112
113 static void map_v4v6_address __P((const char *src, char *dst));
114 static void map_v4v6_hostent __P((struct hostent *hp, char **bp, int *len));
115
116 #ifdef RESOLVSORT
117 static void addrsort __P((char **, int));
118 #endif
119
120 #if PACKETSZ > 1024
121 #define MAXPACKET       PACKETSZ
122 #else
123 #define MAXPACKET       1024
124 #endif
125
126 typedef union {
127     HEADER hdr;
128     u_char buf[MAXPACKET];
129 } querybuf;
130
131 typedef union {
132     int32_t al;
133     char ac;
134 } align;
135
136 extern int h_errno;
137
138 #ifdef DEBUG
139 static void
140 dprintf(msg, num)
141         char *msg;
142         int num;
143 {
144         if (_res.options & RES_DEBUG) {
145                 int save = errno;
146
147                 printf(msg, num);
148                 __set_errno (save);
149         }
150 }
151 #else
152 # define dprintf(msg, num) /*nada*/
153 #endif
154
155 static struct hostent *
156 getanswer(answer, anslen, qname, qtype)
157         const querybuf *answer;
158         int anslen;
159         const char *qname;
160         int qtype;
161 {
162         register const HEADER *hp;
163         register const u_char *cp;
164         register int n;
165         const u_char *eom;
166         char *bp, **ap, **hap;
167         int type, class, buflen, ancount, qdcount;
168         int haveanswer, had_error;
169         int toobig = 0;
170         char tbuf[MAXDNAME];
171         const char *tname;
172         int (*name_ok) __P((const char *));
173
174         tname = qname;
175         host.h_name = NULL;
176         eom = answer->buf + anslen;
177         switch (qtype) {
178         case T_A:
179         case T_AAAA:
180                 name_ok = res_hnok;
181                 break;
182         case T_PTR:
183                 name_ok = res_dnok;
184                 break;
185         default:
186                 return (NULL);  /* XXX should be abort(); */
187         }
188         /*
189          * find first satisfactory answer
190          */
191         hp = &answer->hdr;
192         ancount = ntohs(hp->ancount);
193         qdcount = ntohs(hp->qdcount);
194         bp = hostbuf;
195         buflen = sizeof hostbuf;
196         cp = answer->buf + HFIXEDSZ;
197         if (qdcount != 1) {
198                 __set_h_errno (NO_RECOVERY);
199                 return (NULL);
200         }
201         n = dn_expand(answer->buf, eom, cp, bp, buflen);
202         if ((n < 0) || !(*name_ok)(bp)) {
203                 __set_h_errno (NO_RECOVERY);
204                 return (NULL);
205         }
206         cp += n + QFIXEDSZ;
207         if (qtype == T_A || qtype == T_AAAA) {
208                 /* res_send() has already verified that the query name is the
209                  * same as the one we sent; this just gets the expanded name
210                  * (i.e., with the succeeding search-domain tacked on).
211                  */
212                 n = strlen(bp) + 1;             /* for the \0 */
213                 host.h_name = bp;
214                 bp += n;
215                 buflen -= n;
216                 /* The qname can be abbreviated, but h_name is now absolute. */
217                 qname = host.h_name;
218         }
219         ap = host_aliases;
220         *ap = NULL;
221         host.h_aliases = host_aliases;
222         hap = h_addr_ptrs;
223         *hap = NULL;
224         host.h_addr_list = h_addr_ptrs;
225         haveanswer = 0;
226         had_error = 0;
227         while (ancount-- > 0 && cp < eom && !had_error) {
228                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
229                 if ((n < 0) || !(*name_ok)(bp)) {
230                         had_error++;
231                         continue;
232                 }
233                 cp += n;                        /* name */
234                 type = _getshort(cp);
235                 cp += INT16SZ;                  /* type */
236                 class = _getshort(cp);
237                 cp += INT16SZ + INT32SZ;        /* class, TTL */
238                 n = _getshort(cp);
239                 cp += INT16SZ;                  /* len */
240                 if (class != C_IN) {
241                         /* XXX - debug? syslog? */
242                         cp += n;
243                         continue;               /* XXX - had_error++ ? */
244                 }
245                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
246                         if (ap >= &host_aliases[MAXALIASES-1])
247                                 continue;
248                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
249                         if ((n < 0) || !(*name_ok)(tbuf)) {
250                                 had_error++;
251                                 continue;
252                         }
253                         cp += n;
254                         /* Store alias. */
255                         *ap++ = bp;
256                         n = strlen(bp) + 1;     /* for the \0 */
257                         bp += n;
258                         buflen -= n;
259                         /* Get canonical name. */
260                         n = strlen(tbuf) + 1;   /* for the \0 */
261                         if (n > buflen) {
262                                 had_error++;
263                                 continue;
264                         }
265                         strcpy(bp, tbuf);
266                         host.h_name = bp;
267                         bp += n;
268                         buflen -= n;
269                         continue;
270                 }
271                 if (qtype == T_PTR && type == T_CNAME) {
272                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
273                         if ((n < 0) || !res_hnok(tbuf)) {
274                                 had_error++;
275                                 continue;
276                         }
277                         cp += n;
278                         /* Get canonical name. */
279                         n = strlen(tbuf) + 1;   /* for the \0 */
280                         if (n > buflen) {
281                                 had_error++;
282                                 continue;
283                         }
284                         strcpy(bp, tbuf);
285                         tname = bp;
286                         bp += n;
287                         buflen -= n;
288                         continue;
289                 }
290                 if (type != qtype) {
291                         syslog(LOG_NOTICE|LOG_AUTH,
292                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
293                                qname, p_class(C_IN), p_type(qtype),
294                                p_type(type));
295                         cp += n;
296                         continue;               /* XXX - had_error++ ? */
297                 }
298                 switch (type) {
299                 case T_PTR:
300                         if (strcasecmp(tname, bp) != 0) {
301                                 syslog(LOG_NOTICE|LOG_AUTH,
302                                        AskedForGot, qname, bp);
303                                 cp += n;
304                                 continue;       /* XXX - had_error++ ? */
305                         }
306                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
307                         if ((n < 0) || !res_hnok(bp)) {
308                                 had_error++;
309                                 break;
310                         }
311 #if MULTI_PTRS_ARE_ALIASES
312                         cp += n;
313                         if (!haveanswer)
314                                 host.h_name = bp;
315                         else if (ap < &host_aliases[MAXALIASES-1])
316                                 *ap++ = bp;
317                         else
318                                 n = -1;
319                         if (n != -1) {
320                                 n = strlen(bp) + 1;     /* for the \0 */
321                                 bp += n;
322                                 buflen -= n;
323                         }
324                         break;
325 #else
326                         host.h_name = bp;
327                         if (_res.options & RES_USE_INET6) {
328                                 n = strlen(bp) + 1;     /* for the \0 */
329                                 bp += n;
330                                 buflen -= n;
331                                 map_v4v6_hostent(&host, &bp, &buflen);
332                         }
333                         __set_h_errno (NETDB_SUCCESS);
334                         return (&host);
335 #endif
336                 case T_A:
337                 case T_AAAA:
338                         if (strcasecmp(host.h_name, bp) != 0) {
339                                 syslog(LOG_NOTICE|LOG_AUTH,
340                                        AskedForGot, host.h_name, bp);
341                                 cp += n;
342                                 continue;       /* XXX - had_error++ ? */
343                         }
344                         if (haveanswer) {
345                                 if (n != host.h_length) {
346                                         cp += n;
347                                         continue;
348                                 }
349                         } else {
350                                 register int nn;
351
352                                 host.h_name = bp;
353                                 nn = strlen(bp) + 1;    /* for the \0 */
354                                 bp += nn;
355                                 buflen -= nn;
356                         }
357
358                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
359
360                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
361                                 dprintf("size (%d) too big\n", n);
362                                 had_error++;
363                                 continue;
364                         }
365                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
366                                 if (!toobig++)
367                                         dprintf("Too many addresses (%d)\n",
368                                                 MAXADDRS);
369                                 cp += n;
370                                 continue;
371                         }
372                         bcopy(cp, *hap++ = bp, n);
373                         bp += n;
374                         buflen -= n;
375                         cp += n;
376                         break;
377                 default:
378                         abort();
379                 }
380                 if (!had_error)
381                         haveanswer++;
382         }
383         if (haveanswer) {
384                 *ap = NULL;
385                 *hap = NULL;
386 # if defined(RESOLVSORT)
387                 /*
388                  * Note: we sort even if host can take only one address
389                  * in its return structures - should give it the "best"
390                  * address in that case, not some random one
391                  */
392                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
393                         addrsort(h_addr_ptrs, haveanswer);
394 # endif /*RESOLVSORT*/
395                 if (!host.h_name) {
396                         n = strlen(qname) + 1;  /* for the \0 */
397                         if (n > buflen)
398                                 goto try_again;
399                         strcpy(bp, qname);
400                         host.h_name = bp;
401                         bp += n;
402                         buflen -= n;
403                 }
404                 if (_res.options & RES_USE_INET6)
405                         map_v4v6_hostent(&host, &bp, &buflen);
406                 __set_h_errno (NETDB_SUCCESS);
407                 return (&host);
408         }
409  try_again:
410         __set_h_errno (TRY_AGAIN);
411         return (NULL);
412 }
413
414 struct hostent *
415 gethostbyname(name)
416         const char *name;
417 {
418         struct hostent *hp;
419
420         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
421                 __set_h_errno (NETDB_INTERNAL);
422                 return (NULL);
423        }
424         if (_res.options & RES_USE_INET6) {
425                 hp = gethostbyname2(name, AF_INET6);
426                 if (hp)
427                         return (hp);
428         }
429         return (gethostbyname2(name, AF_INET));
430 }
431
432 struct hostent *
433 gethostbyname2(name, af)
434         const char *name;
435         int af;
436 {
437         querybuf buf;
438         register const char *cp;
439         char *bp;
440         int n, size, type, len;
441         extern struct hostent *_gethtbyname2();
442
443         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
444                 __set_h_errno (NETDB_INTERNAL);
445                 return (NULL);
446         }
447
448         switch (af) {
449         case AF_INET:
450                 size = INADDRSZ;
451                 type = T_A;
452                 break;
453         case AF_INET6:
454                 size = IN6ADDRSZ;
455                 type = T_AAAA;
456                 break;
457         default:
458                 __set_h_errno (NETDB_INTERNAL);
459                 errno = EAFNOSUPPORT;
460                 return (NULL);
461         }
462
463         host.h_addrtype = af;
464         host.h_length = size;
465
466         /*
467          * if there aren't any dots, it could be a user-level alias.
468          * this is also done in res_query() since we are not the only
469          * function that looks up host names.
470          */
471         if (!strchr(name, '.') && (cp = __hostalias(name)))
472                 name = cp;
473
474         /*
475          * disallow names consisting only of digits/dots, unless
476          * they end in a dot.
477          */
478         if (isdigit(name[0]))
479                 for (cp = name;; ++cp) {
480                         if (!*cp) {
481                                 if (*--cp == '.')
482                                         break;
483                                 /*
484                                  * All-numeric, no dot at the end.
485                                  * Fake up a hostent as if we'd actually
486                                  * done a lookup.
487                                  */
488                                 if (inet_pton(af, name, host_addr) <= 0) {
489                                         __set_h_errno (HOST_NOT_FOUND);
490                                         return (NULL);
491                                 }
492                                 strncpy(hostbuf, name, MAXDNAME);
493                                 hostbuf[MAXDNAME] = '\0';
494                                 bp = hostbuf + MAXDNAME;
495                                 len = sizeof hostbuf - MAXDNAME;
496                                 host.h_name = hostbuf;
497                                 host.h_aliases = host_aliases;
498                                 host_aliases[0] = NULL;
499                                 h_addr_ptrs[0] = (char *)host_addr;
500                                 h_addr_ptrs[1] = NULL;
501                                 host.h_addr_list = h_addr_ptrs;
502                                 if (_res.options & RES_USE_INET6)
503                                         map_v4v6_hostent(&host, &bp, &len);
504                                 __set_h_errno (NETDB_SUCCESS);
505                                 return (&host);
506                         }
507                         if (!isdigit(*cp) && *cp != '.')
508                                 break;
509                }
510         if (isxdigit(name[0]) || name[0] == ':')
511                 for (cp = name;; ++cp) {
512                         if (!*cp) {
513                                 if (*--cp == '.')
514                                         break;
515                                 /*
516                                  * All-IPv6-legal, no dot at the end.
517                                  * Fake up a hostent as if we'd actually
518                                  * done a lookup.
519                                  */
520                                 if (inet_pton(af, name, host_addr) <= 0) {
521                                         __set_h_errno (HOST_NOT_FOUND);
522                                         return (NULL);
523                                 }
524                                 strncpy(hostbuf, name, MAXDNAME);
525                                 hostbuf[MAXDNAME] = '\0';
526                                 bp = hostbuf + MAXDNAME;
527                                 len = sizeof hostbuf - MAXDNAME;
528                                 host.h_name = hostbuf;
529                                 host.h_aliases = host_aliases;
530                                 host_aliases[0] = NULL;
531                                 h_addr_ptrs[0] = (char *)host_addr;
532                                 h_addr_ptrs[1] = NULL;
533                                 host.h_addr_list = h_addr_ptrs;
534                                 __set_h_errno (NETDB_SUCCESS);
535                                 return (&host);
536                         }
537                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
538                                 break;
539                 }
540
541         if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) {
542                 dprintf("res_search failed (%d)\n", n);
543                 if (errno == ECONNREFUSED)
544                         return (_gethtbyname2(name, af));
545                 return (NULL);
546         }
547         return (getanswer(&buf, n, name, type));
548 }
549
550 struct hostent *
551 gethostbyaddr(addr, len, af)
552         const char *addr;       /* XXX should have been def'd as u_char! */
553         int len, af;
554 {
555         const u_char *uaddr = (const u_char *)addr;
556         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
557         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
558         int n, size;
559         querybuf buf;
560         register struct hostent *hp;
561         char qbuf[MAXDNAME+1], *qp;
562 #ifdef SUNSECURITY
563         register struct hostent *rhp;
564         char **haddr;
565         u_long old_options;
566         char hname2[MAXDNAME+1];
567 #endif /*SUNSECURITY*/
568         extern struct hostent *_gethtbyaddr();
569
570         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
571                 __set_h_errno (NETDB_INTERNAL);
572                 return (NULL);
573         }
574         if (af == AF_INET6 && len == IN6ADDRSZ &&
575             (!bcmp(uaddr, mapped, sizeof mapped) ||
576              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
577                 /* Unmap. */
578                 addr += sizeof mapped;
579                 uaddr += sizeof mapped;
580                 af = AF_INET;
581                 len = INADDRSZ;
582         }
583         switch (af) {
584         case AF_INET:
585                 size = INADDRSZ;
586                 break;
587         case AF_INET6:
588                 size = IN6ADDRSZ;
589                 break;
590         default:
591                 __set_errno (EAFNOSUPPORT);
592                 __set_h_errno (NETDB_INTERNAL);
593                 return (NULL);
594         }
595         if (size != len) {
596                 __set_errno (EINVAL);
597                 __set_h_errno (NETDB_INTERNAL);
598                 return (NULL);
599         }
600         switch (af) {
601         case AF_INET:
602                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
603                                (uaddr[3] & 0xff),
604                                (uaddr[2] & 0xff),
605                                (uaddr[1] & 0xff),
606                                (uaddr[0] & 0xff));
607                 break;
608         case AF_INET6:
609                 qp = qbuf;
610                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
611                         qp += SPRINTF((qp, "%x.%x.",
612                                        uaddr[n] & 0xf,
613                                        (uaddr[n] >> 4) & 0xf));
614                 }
615                 strcpy(qp, "ip6.int");
616                 break;
617         default:
618                 abort();
619         }
620         n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
621         if (n < 0) {
622                 dprintf("res_query failed (%d)\n", n);
623                 if (errno == ECONNREFUSED)
624                         return (_gethtbyaddr(addr, len, af));
625                 return (NULL);
626         }
627         if (!(hp = getanswer(&buf, n, qbuf, T_PTR)))
628                 return (NULL);  /* h_errno was set by getanswer() */
629 #ifdef SUNSECURITY
630         if (af == AF_INET) {
631             /*
632              * turn off search as the name should be absolute,
633              * 'localhost' should be matched by defnames
634              */
635             strncpy(hname2, hp->h_name, MAXDNAME);
636             hname2[MAXDNAME] = '\0';
637             old_options = _res.options;
638             _res.options &= ~RES_DNSRCH;
639             _res.options |= RES_DEFNAMES;
640             if (!(rhp = gethostbyname(hname2))) {
641                 syslog(LOG_NOTICE|LOG_AUTH,
642                        "gethostbyaddr: No A record for %s (verifying [%s])",
643                        hname2, inet_ntoa(*((struct in_addr *)addr)));
644                 _res.options = old_options;
645                 __set_h_errno (HOST_NOT_FOUND);
646                 return (NULL);
647             }
648             _res.options = old_options;
649             for (haddr = rhp->h_addr_list; *haddr; haddr++)
650                 if (!memcmp(*haddr, addr, INADDRSZ))
651                         break;
652             if (!*haddr) {
653                 syslog(LOG_NOTICE|LOG_AUTH,
654                        "gethostbyaddr: A record of %s != PTR record [%s]",
655                        hname2, inet_ntoa(*((struct in_addr *)addr)));
656                 __set_h_errno (HOST_NOT_FOUND);
657                 return (NULL);
658             }
659         }
660 #endif /*SUNSECURITY*/
661         hp->h_addrtype = af;
662         hp->h_length = len;
663         bcopy(addr, host_addr, len);
664         h_addr_ptrs[0] = (char *)host_addr;
665         h_addr_ptrs[1] = NULL;
666         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
667                 map_v4v6_address((char*)host_addr, (char*)host_addr);
668                 hp->h_addrtype = AF_INET6;
669                 hp->h_length = IN6ADDRSZ;
670         }
671         __set_h_errno (NETDB_SUCCESS);
672         return (hp);
673 }
674
675 void
676 _sethtent(f)
677         int f;
678 {
679         if (!hostf)
680                 hostf = fopen(_PATH_HOSTS, "r" );
681         else
682                 rewind(hostf);
683         stayopen = f;
684 }
685
686 void
687 _endhtent()
688 {
689         if (hostf && !stayopen) {
690                 (void) fclose(hostf);
691                 hostf = NULL;
692         }
693 }
694
695 struct hostent *
696 _gethtent()
697 {
698         char *p;
699         register char *cp, **q;
700         int af, len;
701
702         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
703                 __set_h_errno (NETDB_INTERNAL);
704                 return (NULL);
705         }
706  again:
707         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
708                 __set_h_errno (HOST_NOT_FOUND);
709                 return (NULL);
710         }
711         if (*p == '#')
712                 goto again;
713         if (!(cp = strpbrk(p, "#\n")))
714                 goto again;
715         *cp = '\0';
716         if (!(cp = strpbrk(p, " \t")))
717                 goto again;
718         *cp++ = '\0';
719         if ((_res.options & RES_USE_INET6) &&
720             inet_pton(AF_INET6, p, host_addr) > 0) {
721                 af = AF_INET6;
722                 len = IN6ADDRSZ;
723         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
724                 if (_res.options & RES_USE_INET6) {
725                         map_v4v6_address((char*)host_addr, (char*)host_addr);
726                         af = AF_INET6;
727                         len = IN6ADDRSZ;
728                 } else {
729                         af = AF_INET;
730                         len = INADDRSZ;
731                 }
732         } else {
733                 goto again;
734         }
735         h_addr_ptrs[0] = (char *)host_addr;
736         h_addr_ptrs[1] = NULL;
737         host.h_addr_list = h_addr_ptrs;
738         host.h_length = len;
739         host.h_addrtype = af;
740         while (*cp == ' ' || *cp == '\t')
741                 cp++;
742         host.h_name = cp;
743         q = host.h_aliases = host_aliases;
744         if (cp = strpbrk(cp, " \t"))
745                 *cp++ = '\0';
746         while (cp && *cp) {
747                 if (*cp == ' ' || *cp == '\t') {
748                         cp++;
749                         continue;
750                 }
751                 if (q < &host_aliases[MAXALIASES - 1])
752                         *q++ = cp;
753                 if (cp = strpbrk(cp, " \t"))
754                         *cp++ = '\0';
755         }
756         *q = NULL;
757         if (_res.options & RES_USE_INET6) {
758                 char *bp = hostbuf;
759                 int buflen = sizeof hostbuf;
760
761                 map_v4v6_hostent(&host, &bp, &buflen);
762         }
763         __set_h_errno (NETDB_SUCCESS);
764         return (&host);
765 }
766
767 struct hostent *
768 _gethtbyname(name)
769         const char *name;
770 {
771         extern struct hostent *_gethtbyname2();
772         struct hostent *hp;
773
774         if (_res.options & RES_USE_INET6) {
775                 hp = _gethtbyname2(name, AF_INET6);
776                 if (hp)
777                         return (hp);
778         }
779         return (_gethtbyname2(name, AF_INET));
780 }
781
782 struct hostent *
783 _gethtbyname2(name, af)
784         const char *name;
785         int af;
786 {
787         register struct hostent *p;
788         register char **cp;
789
790         _sethtent(0);
791         while (p = _gethtent()) {
792                 if (p->h_addrtype != af)
793                         continue;
794                 if (strcasecmp(p->h_name, name) == 0)
795                         break;
796                 for (cp = p->h_aliases; *cp != 0; cp++)
797                         if (strcasecmp(*cp, name) == 0)
798                                 goto found;
799         }
800  found:
801         _endhtent();
802         return (p);
803 }
804
805 struct hostent *
806 _gethtbyaddr(addr, len, af)
807         const char *addr;
808         int len, af;
809 {
810         register struct hostent *p;
811
812         _sethtent(0);
813         while (p = _gethtent())
814                 if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
815                         break;
816         _endhtent();
817         return (p);
818 }
819
820 static void
821 map_v4v6_address(src, dst)
822         const char *src;
823         char *dst;
824 {
825         u_char *p = (u_char *)dst;
826         char tmp[INADDRSZ];
827         int i;
828
829         /* Stash a temporary copy so our caller can update in place. */
830         bcopy(src, tmp, INADDRSZ);
831         /* Mark this ipv6 addr as a mapped ipv4. */
832         for (i = 0; i < 10; i++)
833                 *p++ = 0x00;
834         *p++ = 0xff;
835         *p++ = 0xff;
836         /* Retrieve the saved copy and we're done. */
837         bcopy(tmp, (void*)p, INADDRSZ);
838 }
839
840 static void
841 map_v4v6_hostent(hp, bpp, lenp)
842         struct hostent *hp;
843         char **bpp;
844         int *lenp;
845 {
846         char **ap;
847
848         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
849                 return;
850         hp->h_addrtype = AF_INET6;
851         hp->h_length = IN6ADDRSZ;
852         for (ap = hp->h_addr_list; *ap; ap++) {
853                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
854
855                 if (*lenp < (i + IN6ADDRSZ)) {
856                         /* Out of memory.  Truncate address list here.  XXX */
857                         *ap = NULL;
858                         return;
859                 }
860                 *bpp += i;
861                 *lenp -= i;
862                 map_v4v6_address(*ap, *bpp);
863                 *ap = *bpp;
864                 *bpp += IN6ADDRSZ;
865                 *lenp -= IN6ADDRSZ;
866         }
867 }
868
869 #ifdef RESOLVSORT
870 static void
871 addrsort(ap, num)
872         char **ap;
873         int num;
874 {
875         int i, j;
876         char **p;
877         short aval[MAXADDRS];
878         int needsort = 0;
879
880         p = ap;
881         for (i = 0; i < num; i++, p++) {
882             for (j = 0 ; (unsigned)j < _res.nsort; j++)
883                 if (_res.sort_list[j].addr.s_addr ==
884                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
885                         break;
886             aval[i] = j;
887             if (needsort == 0 && i > 0 && j < aval[i-1])
888                 needsort = i;
889         }
890         if (!needsort)
891             return;
892
893         while (needsort < num) {
894             for (j = needsort - 1; j >= 0; j--) {
895                 if (aval[j] > aval[j+1]) {
896                     char *hp;
897
898                     i = aval[j];
899                     aval[j] = aval[j+1];
900                     aval[j+1] = i;
901
902                     hp = ap[j];
903                     ap[j] = ap[j+1];
904                     ap[j+1] = hp;
905
906                 } else
907                     break;
908             }
909             needsort++;
910         }
911 }
912 #endif
913
914 #if defined(BSD43_BSD43_NFS) || defined(sun)
915 /* some libc's out there are bound internally to these names (UMIPS) */
916 void
917 ht_sethostent(stayopen)
918         int stayopen;
919 {
920         _sethtent(stayopen);
921 }
922
923 void
924 ht_endhostent()
925 {
926         _endhtent();
927 }
928
929 struct hostent *
930 ht_gethostbyname(name)
931         char *name;
932 {
933         return (_gethtbyname(name));
934 }
935
936 struct hostent *
937 ht_gethostbyaddr(addr, len, af)
938         const char *addr;
939         int len, af;
940 {
941         return (_gethtbyaddr(addr, len, af));
942 }
943
944 struct hostent *
945 gethostent()
946 {
947         return (_gethtent());
948 }
949
950 void
951 dns_service()
952 {
953         return;
954 }
955
956 #undef dn_skipname
957 dn_skipname(comp_dn, eom)
958         const u_char *comp_dn, *eom;
959 {
960         return (__dn_skipname(comp_dn, eom));
961 }
962 #endif /*old-style libc with yp junk in it*/