(MAXPACKET): Increase minimum value from 1024 to 65536, to avoid buffer overrun.
[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  * 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 #define RESOLVSORT
72
73 #ifndef LOG_AUTH
74 # define LOG_AUTH 0
75 #endif
76
77 #define MULTI_PTRS_ARE_ALIASES 1        /* XXX - experimental */
78
79 #if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
80 # include <stdlib.h>
81 # include <string.h>
82 #else
83 # include "../conf/portability.h"
84 #endif
85
86 #if defined(USE_OPTIONS_H)
87 # include <../conf/options.h>
88 #endif
89
90 #ifdef SPRINTF_CHAR
91 # define SPRINTF(x) strlen(sprintf/**/x)
92 #else
93 # define SPRINTF(x) ((size_t)sprintf x)
94 #endif
95
96 #define MAXALIASES      35
97 #define MAXADDRS        35
98
99 static const char AskedForGot[] =
100                           "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
101
102 static char *h_addr_ptrs[MAXADDRS + 1];
103
104 static struct hostent host;
105 static char *host_aliases[MAXALIASES];
106 static char hostbuf[8*1024];
107 static u_char host_addr[16];    /* IPv4 or IPv6 */
108 static FILE *hostf = NULL;
109 static int stayopen = 0;
110
111 static void map_v4v6_address __P((const char *src, char *dst));
112 static void map_v4v6_hostent __P((struct hostent *hp, char **bp, int *len));
113
114 #ifdef RESOLVSORT
115 extern void addrsort __P((char **, int));
116 #endif
117
118 #if PACKETSZ > 65536
119 #define MAXPACKET       PACKETSZ
120 #else
121 #define MAXPACKET       65536
122 #endif
123
124 /* As per RFC 1034 and 1035 a host name cannot exceed 255 octets in length.  */
125 #ifdef MAXHOSTNAMELEN
126 # undef MAXHOSTNAMELEN
127 #endif
128 #define MAXHOSTNAMELEN 256
129
130 typedef union {
131     HEADER hdr;
132     u_char buf[MAXPACKET];
133 } querybuf;
134
135 typedef union {
136     int32_t al;
137     char ac;
138 } align;
139
140 #ifndef h_errno
141 extern int h_errno;
142 #endif
143
144 #ifdef DEBUG
145 static void
146 dprintf(msg, num)
147         char *msg;
148         int num;
149 {
150         if (_res.options & RES_DEBUG) {
151                 int save = errno;
152
153                 printf(msg, num);
154                 __set_errno (save);
155         }
156 }
157 #else
158 # define dprintf(msg, num) /*nada*/
159 #endif
160
161 #define BOUNDED_INCR(x) \
162         do { \
163                 cp += x; \
164                 if (cp > eom) { \
165                         __set_h_errno (NO_RECOVERY); \
166                         return (NULL); \
167                 } \
168         } while (0)
169
170 #define BOUNDS_CHECK(ptr, count) \
171         do { \
172                 if ((ptr) + (count) > eom) { \
173                         __set_h_errno (NO_RECOVERY); \
174                         return (NULL); \
175                 } \
176         } while (0)
177
178
179 static struct hostent *
180 getanswer(answer, anslen, qname, qtype)
181         const querybuf *answer;
182         int anslen;
183         const char *qname;
184         int qtype;
185 {
186         register const HEADER *hp;
187         register const u_char *cp;
188         register int n;
189         const u_char *eom, *erdata;
190         char *bp, **ap, **hap;
191         int type, class, buflen, ancount, qdcount;
192         int haveanswer, had_error;
193         int toobig = 0;
194         char tbuf[MAXDNAME];
195         const char *tname;
196         int (*name_ok) __P((const char *));
197
198         tname = qname;
199         host.h_name = NULL;
200         eom = answer->buf + anslen;
201         switch (qtype) {
202         case T_A:
203         case T_AAAA:
204                 name_ok = res_hnok;
205                 break;
206         case T_PTR:
207                 name_ok = res_dnok;
208                 break;
209         default:
210                 return (NULL);  /* XXX should be abort(); */
211         }
212         /*
213          * find first satisfactory answer
214          */
215         hp = &answer->hdr;
216         ancount = ntohs(hp->ancount);
217         qdcount = ntohs(hp->qdcount);
218         bp = hostbuf;
219         buflen = sizeof hostbuf;
220         cp = answer->buf;
221         BOUNDED_INCR(HFIXEDSZ);
222         if (qdcount != 1) {
223                 __set_h_errno (NO_RECOVERY);
224                 return (NULL);
225         }
226         n = dn_expand(answer->buf, eom, cp, bp, buflen);
227         if ((n < 0) || !(*name_ok)(bp)) {
228                 __set_h_errno (NO_RECOVERY);
229                 return (NULL);
230         }
231         BOUNDED_INCR(n + QFIXEDSZ);
232         if (qtype == T_A || qtype == T_AAAA) {
233                 /* res_send() has already verified that the query name is the
234                  * same as the one we sent; this just gets the expanded name
235                  * (i.e., with the succeeding search-domain tacked on).
236                  */
237                 n = strlen(bp) + 1;             /* for the \0 */
238                 if (n >= MAXHOSTNAMELEN) {
239                         __set_h_errno (NO_RECOVERY);
240                         return (NULL);
241                 }
242                 host.h_name = bp;
243                 bp += n;
244                 buflen -= n;
245                 /* The qname can be abbreviated, but h_name is now absolute. */
246                 qname = host.h_name;
247         }
248         ap = host_aliases;
249         *ap = NULL;
250         host.h_aliases = host_aliases;
251         hap = h_addr_ptrs;
252         *hap = NULL;
253         host.h_addr_list = h_addr_ptrs;
254         haveanswer = 0;
255         had_error = 0;
256         while (ancount-- > 0 && cp < eom && !had_error) {
257                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
258                 if ((n < 0) || !(*name_ok)(bp)) {
259                         had_error++;
260                         continue;
261                 }
262                 cp += n;                        /* name */
263                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
264                 type = ns_get16(cp);
265                 cp += INT16SZ;                  /* type */
266                 class = ns_get16(cp);
267                 cp += INT16SZ + INT32SZ;        /* class, TTL */
268                 n = ns_get16(cp);
269                 cp += INT16SZ;                  /* len */
270                 BOUNDS_CHECK(cp, n);
271                 erdata = cp + n;
272                 if (class != C_IN) {
273                         /* XXX - debug? syslog? */
274                         cp += n;
275                         continue;               /* XXX - had_error++ ? */
276                 }
277                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
278                         if (ap >= &host_aliases[MAXALIASES-1])
279                                 continue;
280                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
281                         if ((n < 0) || !(*name_ok)(tbuf)) {
282                                 had_error++;
283                                 continue;
284                         }
285                         cp += n;
286                         if (cp != erdata) {
287                                 __set_h_errno (NO_RECOVERY);
288                                 return (NULL);
289                         }
290                         /* Store alias. */
291                         *ap++ = bp;
292                         n = strlen(bp) + 1;     /* for the \0 */
293                         if (n >= MAXHOSTNAMELEN) {
294                                 had_error++;
295                                 continue;
296                         }
297                         bp += n;
298                         buflen -= n;
299                         /* Get canonical name. */
300                         n = strlen(tbuf) + 1;   /* for the \0 */
301                         if (n > buflen || n >= MAXHOSTNAMELEN) {
302                                 had_error++;
303                                 continue;
304                         }
305                         strcpy(bp, tbuf);
306                         host.h_name = bp;
307                         bp += n;
308                         buflen -= n;
309                         continue;
310                 }
311                 if (qtype == T_PTR && type == T_CNAME) {
312                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
313                         if (n < 0 || !res_dnok(tbuf)) {
314                                 had_error++;
315                                 continue;
316                         }
317                         cp += n;
318                         if (cp != erdata) {
319                                 __set_h_errno (NO_RECOVERY);
320                                 return (NULL);
321                         }
322                         /* Get canonical name. */
323                         n = strlen(tbuf) + 1;   /* for the \0 */
324                         if (n > buflen || n >= MAXHOSTNAMELEN) {
325                                 had_error++;
326                                 continue;
327                         }
328                         strcpy(bp, tbuf);
329                         tname = bp;
330                         bp += n;
331                         buflen -= n;
332                         continue;
333                 }
334                 if ((type == T_SIG) || (type == T_KEY) || (type == T_NXT)) {
335                         /* We don't support DNSSEC yet.  For now, ignore
336                          * the record and send a low priority message
337                          * to syslog.
338                          */
339                         syslog(LOG_DEBUG|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                         cp += n;
344                         continue;
345                 }
346                 if (type != qtype) {
347                         syslog(LOG_NOTICE|LOG_AUTH,
348                "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
349                                qname, p_class(C_IN), p_type(qtype),
350                                p_type(type));
351                         cp += n;
352                         continue;               /* XXX - had_error++ ? */
353                 }
354                 switch (type) {
355                 case T_PTR:
356                         if (strcasecmp(tname, bp) != 0) {
357                                 syslog(LOG_NOTICE|LOG_AUTH,
358                                        AskedForGot, qname, bp);
359                                 cp += n;
360                                 continue;       /* XXX - had_error++ ? */
361                         }
362                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
363                         if ((n < 0) || !res_hnok(bp)) {
364                                 had_error++;
365                                 break;
366                         }
367 #if MULTI_PTRS_ARE_ALIASES
368                         cp += n;
369                         if (cp != erdata) {
370                                 __set_h_errno (NO_RECOVERY);
371                                 return (NULL);
372                         }
373                         if (!haveanswer)
374                                 host.h_name = bp;
375                         else if (ap < &host_aliases[MAXALIASES-1])
376                                 *ap++ = bp;
377                         else
378                                 n = -1;
379                         if (n != -1) {
380                                 n = strlen(bp) + 1;     /* for the \0 */
381                                 if (n >= MAXHOSTNAMELEN) {
382                                         had_error++;
383                                         break;
384                                 }
385                                 bp += n;
386                                 buflen -= n;
387                         }
388                         break;
389 #else
390                         host.h_name = bp;
391                         if (_res.options & RES_USE_INET6) {
392                                 n = strlen(bp) + 1;     /* for the \0 */
393                                 if (n >= MAXHOSTNAMELEN) {
394                                         had_error++;
395                                         break;
396                                 }
397                                 bp += n;
398                                 buflen -= n;
399                                 map_v4v6_hostent(&host, &bp, &buflen);
400                         }
401                         __set_h_errno (NETDB_SUCCESS);
402                         return (&host);
403 #endif
404                 case T_A:
405                 case T_AAAA:
406                         if (strcasecmp(host.h_name, bp) != 0) {
407                                 syslog(LOG_NOTICE|LOG_AUTH,
408                                        AskedForGot, host.h_name, bp);
409                                 cp += n;
410                                 continue;       /* XXX - had_error++ ? */
411                         }
412                         if (n != host.h_length) {
413                                 cp += n;
414                                 continue;
415                         }
416                         if (!haveanswer) {
417                                 register int nn;
418
419                                 host.h_name = bp;
420                                 nn = strlen(bp) + 1;    /* for the \0 */
421                                 bp += nn;
422                                 buflen -= nn;
423                         }
424
425                         /* XXX: when incrementing bp, we have to decrement
426                          * buflen by the same amount --okir */
427                         buflen -= sizeof(align) - ((u_long)bp % sizeof(align));
428
429                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
430
431                         if (bp + n >= &hostbuf[sizeof hostbuf]) {
432                                 dprintf("size (%d) too big\n", n);
433                                 had_error++;
434                                 continue;
435                         }
436                         if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
437                                 if (!toobig++) {
438                                         dprintf("Too many addresses (%d)\n",
439                                                 MAXADDRS);
440                                 }
441                                 cp += n;
442                                 continue;
443                         }
444                         memmove(*hap++ = bp, cp, n);
445                         bp += n;
446                         buflen -= n;
447                         cp += n;
448                         if (cp != erdata) {
449                                 __set_h_errno (NO_RECOVERY);
450                                 return (NULL);
451                         }
452                         break;
453                 default:
454                         abort();
455                 }
456                 if (!had_error)
457                         haveanswer++;
458         }
459         if (haveanswer) {
460                 *ap = NULL;
461                 *hap = NULL;
462 # if defined(RESOLVSORT)
463                 /*
464                  * Note: we sort even if host can take only one address
465                  * in its return structures - should give it the "best"
466                  * address in that case, not some random one
467                  */
468                 if (_res.nsort && haveanswer > 1 && qtype == T_A)
469                         addrsort(h_addr_ptrs, haveanswer);
470 # endif /*RESOLVSORT*/
471                 if (!host.h_name) {
472                         n = strlen(qname) + 1;  /* for the \0 */
473                         if (n > buflen || n >= MAXHOSTNAMELEN)
474                                 goto no_recovery;
475                         strcpy(bp, qname);
476                         host.h_name = bp;
477                         bp += n;
478                         buflen -= n;
479                 }
480                 if (_res.options & RES_USE_INET6)
481                         map_v4v6_hostent(&host, &bp, &buflen);
482                 __set_h_errno (NETDB_SUCCESS);
483                 return (&host);
484         }
485  no_recovery:
486         __set_h_errno (NO_RECOVERY);
487         return (NULL);
488 }
489
490 struct hostent *
491 gethostbyname(name)
492         const char *name;
493 {
494         struct hostent *hp;
495
496         if ((_res.options & RES_INIT) == 0 && __res_ninit(&_res) == -1) {
497                 __set_h_errno (NETDB_INTERNAL);
498                 return (NULL);
499        }
500         if (_res.options & RES_USE_INET6) {
501                 hp = gethostbyname2(name, AF_INET6);
502                 if (hp)
503                         return (hp);
504         }
505         return (gethostbyname2(name, AF_INET));
506 }
507
508 struct hostent *
509 gethostbyname2(name, af)
510         const char *name;
511         int af;
512 {
513         querybuf buf;
514         register const char *cp;
515         char *bp;
516         int n, size, type, len;
517         extern struct hostent *_gethtbyname2();
518
519         if ((_res.options & RES_INIT) == 0 && __res_ninit(&_res) == -1) {
520                 __set_h_errno (NETDB_INTERNAL);
521                 return (NULL);
522         }
523
524         switch (af) {
525         case AF_INET:
526                 size = INADDRSZ;
527                 type = T_A;
528                 break;
529         case AF_INET6:
530                 size = IN6ADDRSZ;
531                 type = T_AAAA;
532                 break;
533         default:
534                 __set_h_errno (NETDB_INTERNAL);
535                 __set_errno (EAFNOSUPPORT);
536                 return (NULL);
537         }
538
539         host.h_addrtype = af;
540         host.h_length = size;
541
542         /*
543          * if there aren't any dots, it could be a user-level alias.
544          * this is also done in res_query() since we are not the only
545          * function that looks up host names.
546          */
547         if (!strchr(name, '.') && (cp = __hostalias(name)))
548                 name = cp;
549
550         /*
551          * disallow names consisting only of digits/dots, unless
552          * they end in a dot.
553          */
554         if (isdigit(name[0]))
555                 for (cp = name;; ++cp) {
556                         if (!*cp) {
557                                 if (*--cp == '.')
558                                         break;
559                                 /*
560                                  * All-numeric, no dot at the end.
561                                  * Fake up a hostent as if we'd actually
562                                  * done a lookup.
563                                  */
564                                 if (inet_pton(af, name, host_addr) <= 0) {
565                                         __set_h_errno (HOST_NOT_FOUND);
566                                         return (NULL);
567                                 }
568                                 strncpy(hostbuf, name, MAXDNAME);
569                                 hostbuf[MAXDNAME] = '\0';
570                                 bp = hostbuf + MAXDNAME;
571                                 len = sizeof hostbuf - MAXDNAME;
572                                 host.h_name = hostbuf;
573                                 host.h_aliases = host_aliases;
574                                 host_aliases[0] = NULL;
575                                 h_addr_ptrs[0] = (char *)host_addr;
576                                 h_addr_ptrs[1] = NULL;
577                                 host.h_addr_list = h_addr_ptrs;
578                                 if (_res.options & RES_USE_INET6)
579                                         map_v4v6_hostent(&host, &bp, &len);
580                                 __set_h_errno (NETDB_SUCCESS);
581                                 return (&host);
582                         }
583                         if (!isdigit(*cp) && *cp != '.')
584                                 break;
585                }
586         if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
587             name[0] == ':')
588                 for (cp = name;; ++cp) {
589                         if (!*cp) {
590                                 if (*--cp == '.')
591                                         break;
592                                 /*
593                                  * All-IPv6-legal, no dot at the end.
594                                  * Fake up a hostent as if we'd actually
595                                  * done a lookup.
596                                  */
597                                 if (inet_pton(af, name, host_addr) <= 0) {
598                                         __set_h_errno (HOST_NOT_FOUND);
599                                         return (NULL);
600                                 }
601                                 strncpy(hostbuf, name, MAXDNAME);
602                                 hostbuf[MAXDNAME] = '\0';
603                                 bp = hostbuf + MAXDNAME;
604                                 len = sizeof hostbuf - MAXDNAME;
605                                 host.h_name = hostbuf;
606                                 host.h_aliases = host_aliases;
607                                 host_aliases[0] = NULL;
608                                 h_addr_ptrs[0] = (char *)host_addr;
609                                 h_addr_ptrs[1] = NULL;
610                                 host.h_addr_list = h_addr_ptrs;
611                                 __set_h_errno (NETDB_SUCCESS);
612                                 return (&host);
613                         }
614                         if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
615                                 break;
616                 }
617
618         if ((n = res_nsearch(&_res, name, C_IN, type, buf.buf, sizeof(buf.buf))) < 0) {
619                 dprintf("res_nsearch failed (%d)\n", n);
620                 if (errno == ECONNREFUSED)
621                         return (_gethtbyname2(name, af));
622                 return (NULL);
623         }
624         return (getanswer(&buf, n, name, type));
625 }
626
627 struct hostent *
628 gethostbyaddr(addr, len, af)
629         const void *addr;
630         socklen_t len;
631         int af;
632 {
633         const u_char *uaddr = (const u_char *)addr;
634         static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
635         static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
636         int n, size;
637         querybuf buf;
638         register struct hostent *hp;
639         char qbuf[MAXDNAME+1], *qp = NULL;
640 #ifdef SUNSECURITY
641         register struct hostent *rhp;
642         char **haddr;
643         u_long old_options;
644         char hname2[MAXDNAME+1];
645 #endif /*SUNSECURITY*/
646         extern struct hostent *_gethtbyaddr();
647
648         if ((_res.options & RES_INIT) == 0 && __res_ninit(&_res) == -1) {
649                 __set_h_errno (NETDB_INTERNAL);
650                 return (NULL);
651         }
652         if (af == AF_INET6 && len == IN6ADDRSZ &&
653             (!bcmp(uaddr, mapped, sizeof mapped) ||
654              !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
655                 /* Unmap. */
656                 addr += sizeof mapped;
657                 uaddr += sizeof mapped;
658                 af = AF_INET;
659                 len = INADDRSZ;
660         }
661         switch (af) {
662         case AF_INET:
663                 size = INADDRSZ;
664                 break;
665         case AF_INET6:
666                 size = IN6ADDRSZ;
667                 break;
668         default:
669                 __set_errno (EAFNOSUPPORT);
670                 __set_h_errno (NETDB_INTERNAL);
671                 return (NULL);
672         }
673         if (size != len) {
674                 __set_errno (EINVAL);
675                 __set_h_errno (NETDB_INTERNAL);
676                 return (NULL);
677         }
678         switch (af) {
679         case AF_INET:
680                 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
681                                (uaddr[3] & 0xff),
682                                (uaddr[2] & 0xff),
683                                (uaddr[1] & 0xff),
684                                (uaddr[0] & 0xff));
685                 break;
686         case AF_INET6:
687                 qp = qbuf;
688                 for (n = IN6ADDRSZ - 1; n >= 0; n--) {
689                         qp += SPRINTF((qp, "%x.%x.",
690                                        uaddr[n] & 0xf,
691                                        (uaddr[n] >> 4) & 0xf));
692                 }
693                 strcpy(qp, "ip6.arpa");
694                 break;
695         default:
696                 abort();
697         }
698         n = res_nquery(&_res, qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
699         if (n < 0 && af == AF_INET6) {
700                 strcpy(qp, "ip6.int");
701                 n = res_nquery(&_res, qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
702         }
703         if (n < 0) {
704                 dprintf("res_nquery failed (%d)\n", n);
705                 if (errno == ECONNREFUSED)
706                         return (_gethtbyaddr(addr, len, af));
707                 return (NULL);
708         }
709         if (!(hp = getanswer(&buf, n, qbuf, T_PTR)))
710                 return (NULL);  /* h_errno was set by getanswer() */
711 #ifdef SUNSECURITY
712         if (af == AF_INET) {
713             /*
714              * turn off search as the name should be absolute,
715              * 'localhost' should be matched by defnames
716              */
717             strncpy(hname2, hp->h_name, MAXDNAME);
718             hname2[MAXDNAME] = '\0';
719             old_options = _res.options;
720             _res.options &= ~RES_DNSRCH;
721             _res.options |= RES_DEFNAMES;
722             if (!(rhp = gethostbyname(hname2))) {
723                 syslog(LOG_NOTICE|LOG_AUTH,
724                        "gethostbyaddr: No A record for %s (verifying [%s])",
725                        hname2, inet_ntoa(*((struct in_addr *)addr)));
726                 _res.options = old_options;
727                 __set_h_errno (HOST_NOT_FOUND);
728                 return (NULL);
729             }
730             _res.options = old_options;
731             for (haddr = rhp->h_addr_list; *haddr; haddr++)
732                 if (!memcmp(*haddr, addr, INADDRSZ))
733                         break;
734             if (!*haddr) {
735                 syslog(LOG_NOTICE|LOG_AUTH,
736                        "gethostbyaddr: A record of %s != PTR record [%s]",
737                        hname2, inet_ntoa(*((struct in_addr *)addr)));
738                 __set_h_errno (HOST_NOT_FOUND);
739                 return (NULL);
740             }
741         }
742 #endif /*SUNSECURITY*/
743         hp->h_addrtype = af;
744         hp->h_length = len;
745         memmove(host_addr, addr, len);
746         h_addr_ptrs[0] = (char *)host_addr;
747         h_addr_ptrs[1] = NULL;
748         if (af == AF_INET && (_res.options & RES_USE_INET6)) {
749                 map_v4v6_address((char*)host_addr, (char*)host_addr);
750                 hp->h_addrtype = AF_INET6;
751                 hp->h_length = IN6ADDRSZ;
752         }
753         __set_h_errno (NETDB_SUCCESS);
754         return (hp);
755 }
756
757 void
758 _sethtent(f)
759         int f;
760 {
761         if (!hostf)
762                 hostf = fopen(_PATH_HOSTS, "r" );
763         else
764                 rewind(hostf);
765         stayopen = f;
766 }
767
768 void
769 _endhtent()
770 {
771         if (hostf && !stayopen) {
772                 (void) fclose(hostf);
773                 hostf = NULL;
774         }
775 }
776
777 struct hostent *
778 _gethtent()
779 {
780         char *p;
781         register char *cp, **q;
782         int af, len;
783
784         if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
785                 __set_h_errno (NETDB_INTERNAL);
786                 return (NULL);
787         }
788  again:
789         if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
790                 __set_h_errno (HOST_NOT_FOUND);
791                 return (NULL);
792         }
793         if (*p == '#')
794                 goto again;
795         if (!(cp = strpbrk(p, "#\n")))
796                 goto again;
797         *cp = '\0';
798         if (!(cp = strpbrk(p, " \t")))
799                 goto again;
800         *cp++ = '\0';
801         if (inet_pton(AF_INET6, p, host_addr) > 0) {
802                 af = AF_INET6;
803                 len = IN6ADDRSZ;
804         } else if (inet_pton(AF_INET, p, host_addr) > 0) {
805                 if (_res.options & RES_USE_INET6) {
806                         map_v4v6_address((char*)host_addr, (char*)host_addr);
807                         af = AF_INET6;
808                         len = IN6ADDRSZ;
809                 } else {
810                         af = AF_INET;
811                         len = INADDRSZ;
812                 }
813         } else {
814                 goto again;
815         }
816         h_addr_ptrs[0] = (char *)host_addr;
817         h_addr_ptrs[1] = NULL;
818         host.h_addr_list = h_addr_ptrs;
819         host.h_length = len;
820         host.h_addrtype = af;
821         while (*cp == ' ' || *cp == '\t')
822                 cp++;
823         host.h_name = cp;
824         q = host.h_aliases = host_aliases;
825         if ((cp = strpbrk(cp, " \t")))
826                 *cp++ = '\0';
827         while (cp && *cp) {
828                 if (*cp == ' ' || *cp == '\t') {
829                         cp++;
830                         continue;
831                 }
832                 if (q < &host_aliases[MAXALIASES - 1])
833                         *q++ = cp;
834                 if ((cp = strpbrk(cp, " \t")))
835                         *cp++ = '\0';
836         }
837         *q = NULL;
838         __set_h_errno (NETDB_SUCCESS);
839         return (&host);
840 }
841
842 struct hostent *
843 _gethtbyname(name)
844         const char *name;
845 {
846         extern struct hostent *_gethtbyname2();
847         struct hostent *hp;
848
849         if (_res.options & RES_USE_INET6) {
850                 hp = _gethtbyname2(name, AF_INET6);
851                 if (hp)
852                         return (hp);
853         }
854         return (_gethtbyname2(name, AF_INET));
855 }
856
857 struct hostent *
858 _gethtbyname2(name, af)
859         const char *name;
860         int af;
861 {
862         register struct hostent *p;
863         register char **cp;
864
865         _sethtent(0);
866         while ((p = _gethtent())) {
867                 if (p->h_addrtype != af)
868                         continue;
869                 if (strcasecmp(p->h_name, name) == 0)
870                         break;
871                 for (cp = p->h_aliases; *cp != 0; cp++)
872                         if (strcasecmp(*cp, name) == 0)
873                                 goto found;
874         }
875  found:
876         _endhtent();
877         return (p);
878 }
879
880 struct hostent *
881 _gethtbyaddr(addr, len, af)
882         const char *addr;
883         size_t len;
884         int af;
885 {
886         register struct hostent *p;
887
888         _sethtent(0);
889         while ((p = _gethtent()))
890                 if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
891                         break;
892         _endhtent();
893         return (p);
894 }
895
896 static void
897 map_v4v6_address(src, dst)
898         const char *src;
899         char *dst;
900 {
901         u_char *p = (u_char *)dst;
902         char tmp[INADDRSZ];
903         int i;
904
905         /* Stash a temporary copy so our caller can update in place. */
906         memcpy(tmp, src, INADDRSZ);
907         /* Mark this ipv6 addr as a mapped ipv4. */
908         for (i = 0; i < 10; i++)
909                 *p++ = 0x00;
910         *p++ = 0xff;
911         *p++ = 0xff;
912         /* Retrieve the saved copy and we're done. */
913         memcpy((void*)p, tmp, INADDRSZ);
914 }
915
916 static void
917 map_v4v6_hostent(hp, bpp, lenp)
918         struct hostent *hp;
919         char **bpp;
920         int *lenp;
921 {
922         char **ap;
923
924         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
925                 return;
926         hp->h_addrtype = AF_INET6;
927         hp->h_length = IN6ADDRSZ;
928         for (ap = hp->h_addr_list; *ap; ap++) {
929                 int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
930
931                 if (*lenp < (i + IN6ADDRSZ)) {
932                         /* Out of memory.  Truncate address list here.  XXX */
933                         *ap = NULL;
934                         return;
935                 }
936                 *bpp += i;
937                 *lenp -= i;
938                 map_v4v6_address(*ap, *bpp);
939                 *ap = *bpp;
940                 *bpp += IN6ADDRSZ;
941                 *lenp -= IN6ADDRSZ;
942         }
943 }
944
945 #ifdef RESOLVSORT
946 extern void
947 addrsort(ap, num)
948         char **ap;
949         int num;
950 {
951         int i, j;
952         char **p;
953         short aval[MAXADDRS];
954         int needsort = 0;
955
956         p = ap;
957         for (i = 0; i < num; i++, p++) {
958             for (j = 0 ; (unsigned)j < _res.nsort; j++)
959                 if (_res.sort_list[j].addr.s_addr ==
960                     (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
961                         break;
962             aval[i] = j;
963             if (needsort == 0 && i > 0 && j < aval[i-1])
964                 needsort = i;
965         }
966         if (!needsort)
967             return;
968
969         while (needsort < num) {
970             for (j = needsort - 1; j >= 0; j--) {
971                 if (aval[j] > aval[j+1]) {
972                     char *hp;
973
974                     i = aval[j];
975                     aval[j] = aval[j+1];
976                     aval[j+1] = i;
977
978                     hp = ap[j];
979                     ap[j] = ap[j+1];
980                     ap[j+1] = hp;
981
982                 } else
983                     break;
984             }
985             needsort++;
986         }
987 }
988 #endif
989
990 #if defined(BSD43_BSD43_NFS) || defined(sun)
991 /* some libc's out there are bound internally to these names (UMIPS) */
992 void
993 ht_sethostent(stayopen)
994         int stayopen;
995 {
996         _sethtent(stayopen);
997 }
998
999 void
1000 ht_endhostent()
1001 {
1002         _endhtent();
1003 }
1004
1005 struct hostent *
1006 ht_gethostbyname(name)
1007         char *name;
1008 {
1009         return (_gethtbyname(name));
1010 }
1011
1012 struct hostent *
1013 ht_gethostbyaddr(addr, len, af)
1014         const char *addr;
1015         size_t len;
1016         int af;
1017 {
1018         return (_gethtbyaddr(addr, len, af));
1019 }
1020
1021 struct hostent *
1022 gethostent()
1023 {
1024         return (_gethtent());
1025 }
1026
1027 void
1028 dns_service()
1029 {
1030         return;
1031 }
1032
1033 #undef dn_skipname
1034 dn_skipname(comp_dn, eom)
1035         const u_char *comp_dn, *eom;
1036 {
1037         return (__dn_skipname(comp_dn, eom));
1038 }
1039 #endif /*old-style libc with yp junk in it*/