2 * Copyright (c) 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
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.
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
51 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
53 * Permission to use, copy, modify, and distribute this software for any
54 * purpose with or without fee is hereby granted, provided that the above
55 * copyright notice and this permission notice appear in all copies.
57 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
58 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
59 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
60 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
61 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
62 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
63 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
68 #include <sys/types.h>
69 #include <sys/param.h>
70 #include <netinet/in.h>
71 #include <arpa/inet.h>
72 #include <arpa/nameser.h>
77 #include <resolv/resolv-internal.h>
81 #include <resolv/resolv-internal.h>
83 /* Options. Leave them on. */
87 #define MAXPACKET PACKETSZ
89 #define MAXPACKET 65536
92 #define QUERYSIZE (HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1)
95 __libc_res_nquerydomain(res_state statp
, const char *name
, const char *domain
,
96 int class, int type
, u_char
*answer
, int anslen
,
97 u_char
**answerp
, u_char
**answerp2
, int *nanswerp2
,
98 int *resplen2
, int *answerp2_malloced
);
101 * Formulate a normal query, send, and await answer.
102 * Returned answer is placed in supplied buffer "answer".
103 * Perform preliminary check of answer, returning success only
104 * if no error is indicated and the answer count is nonzero.
105 * Return the size of the response on success, -1 on error.
106 * Error number is left in H_ERRNO.
108 * Caller must parse answer and determine whether it answers the question.
111 __libc_res_nquery(res_state statp
,
112 const char *name
, /* domain name */
113 int class, int type
, /* class and type of query */
114 u_char
*answer
, /* buffer to put answer */
115 int anslen
, /* size of answer buffer */
116 u_char
**answerp
, /* if buffer needs to be enlarged */
120 int *answerp2_malloced
)
122 HEADER
*hp
= (HEADER
*) answer
;
124 int n
, use_malloc
= 0;
126 size_t bufsize
= (type
== T_QUERY_A_AND_AAAA
? 2 : 1) * QUERYSIZE
;
127 u_char
*buf
= alloca (bufsize
);
128 u_char
*query1
= buf
;
130 u_char
*query2
= NULL
;
134 hp
->rcode
= NOERROR
; /* default */
137 if (statp
->options
& RES_DEBUG
)
138 printf(";; res_query(%s, %d, %d)\n", name
, class, type
);
141 if (type
== T_QUERY_A_AND_AAAA
)
143 n
= res_nmkquery(statp
, QUERY
, name
, class, T_A
, NULL
, 0, NULL
,
147 if ((statp
->options
& (RES_USE_EDNS0
|RES_USE_DNSSEC
)) != 0)
149 /* Use RESOLV_EDNS_BUFFER_SIZE because the receive
150 buffer can be reallocated. */
151 n
= __res_nopt (statp
, n
, query1
, bufsize
,
152 RESOLV_EDNS_BUFFER_SIZE
);
158 /* Align the buffer. */
159 int npad
= ((nquery1
+ __alignof__ (HEADER
) - 1)
160 & ~(__alignof__ (HEADER
) - 1)) - nquery1
;
161 if (n
> bufsize
- npad
)
166 int nused
= n
+ npad
;
167 query2
= buf
+ nused
;
168 n
= res_nmkquery(statp
, QUERY
, name
, class, T_AAAA
, NULL
, 0,
169 NULL
, query2
, bufsize
- nused
);
171 && (statp
->options
& (RES_USE_EDNS0
|RES_USE_DNSSEC
)) != 0)
172 /* Use RESOLV_EDNS_BUFFER_SIZE because the receive
173 buffer can be reallocated. */
174 n
= __res_nopt (statp
, n
, query2
, bufsize
,
175 RESOLV_EDNS_BUFFER_SIZE
);
183 n
= res_nmkquery(statp
, QUERY
, name
, class, type
, NULL
, 0, NULL
,
187 && (statp
->options
& (RES_USE_EDNS0
|RES_USE_DNSSEC
)) != 0)
189 /* Use RESOLV_EDNS_BUFFER_SIZE if the receive buffer
190 can be reallocated. */
195 advertise
= RESOLV_EDNS_BUFFER_SIZE
;
196 n
= __res_nopt (statp
, n
, query1
, bufsize
, advertise
);
202 if (__glibc_unlikely (n
<= 0) && !use_malloc
) {
203 /* Retry just in case res_nmkquery failed because of too
204 short buffer. Shouldn't happen. */
205 bufsize
= (type
== T_QUERY_A_AND_AAAA
? 2 : 1) * MAXPACKET
;
206 buf
= malloc (bufsize
);
213 if (__glibc_unlikely (n
<= 0)) {
215 if (statp
->options
& RES_DEBUG
)
216 printf(";; res_query: mkquery failed\n");
218 RES_SET_H_ERRNO(statp
, NO_RECOVERY
);
223 assert (answerp
== NULL
|| (void *) *answerp
== (void *) answer
);
224 n
= __libc_res_nsend(statp
, query1
, nquery1
, query2
, nquery2
, answer
,
225 anslen
, answerp
, answerp2
, nanswerp2
, resplen2
,
231 if (statp
->options
& RES_DEBUG
)
232 printf(";; res_query: send error\n");
234 RES_SET_H_ERRNO(statp
, TRY_AGAIN
);
239 /* __libc_res_nsend might have reallocated the buffer. */
240 hp
= (HEADER
*) *answerp
;
242 /* We simplify the following tests by assigning HP to HP2 or
243 vice versa. It is easy to verify that this is the same as
244 ignoring all tests of HP or HP2. */
245 if (answerp2
== NULL
|| *resplen2
< (int) sizeof (HEADER
))
251 hp2
= (HEADER
*) *answerp2
;
252 if (n
< (int) sizeof (HEADER
))
258 /* Make sure both hp and hp2 are defined */
259 assert((hp
!= NULL
) && (hp2
!= NULL
));
261 if ((hp
->rcode
!= NOERROR
|| ntohs(hp
->ancount
) == 0)
262 && (hp2
->rcode
!= NOERROR
|| ntohs(hp2
->ancount
) == 0)) {
264 if (statp
->options
& RES_DEBUG
) {
265 printf(";; rcode = %d, ancount=%d\n", hp
->rcode
,
268 printf(";; rcode2 = %d, ancount2=%d\n", hp2
->rcode
,
269 ntohs(hp2
->ancount
));
272 switch (hp
->rcode
== NOERROR
? hp2
->rcode
: hp
->rcode
) {
274 if ((hp
->rcode
== NOERROR
&& ntohs (hp
->ancount
) != 0)
275 || (hp2
->rcode
== NOERROR
276 && ntohs (hp2
->ancount
) != 0))
278 RES_SET_H_ERRNO(statp
, HOST_NOT_FOUND
);
281 RES_SET_H_ERRNO(statp
, TRY_AGAIN
);
284 if (ntohs (hp
->ancount
) != 0
285 || ntohs (hp2
->ancount
) != 0)
287 RES_SET_H_ERRNO(statp
, NO_DATA
);
291 /* Servers must not reply to AAAA queries with
292 NOTIMP etc but some of them do. */
293 if ((hp
->rcode
== NOERROR
&& ntohs (hp
->ancount
) != 0)
294 || (hp2
->rcode
== NOERROR
295 && ntohs (hp2
->ancount
) != 0))
300 RES_SET_H_ERRNO(statp
, NO_RECOVERY
);
308 libresolv_hidden_def (__libc_res_nquery
)
311 res_nquery(res_state statp
,
312 const char *name
, /* domain name */
313 int class, int type
, /* class and type of query */
314 u_char
*answer
, /* buffer to put answer */
315 int anslen
) /* size of answer buffer */
317 return __libc_res_nquery(statp
, name
, class, type
, answer
, anslen
,
318 NULL
, NULL
, NULL
, NULL
, NULL
);
320 libresolv_hidden_def (res_nquery
)
323 * Formulate a normal query, send, and retrieve answer in supplied buffer.
324 * Return the size of the response on success, -1 on error.
325 * If enabled, implement search rules until answer or unrecoverable failure
326 * is detected. Error code, if any, is left in H_ERRNO.
329 __libc_res_nsearch(res_state statp
,
330 const char *name
, /* domain name */
331 int class, int type
, /* class and type of query */
332 u_char
*answer
, /* buffer to put answer */
333 int anslen
, /* size of answer */
338 int *answerp2_malloced
)
340 const char *cp
, * const *domain
;
341 HEADER
*hp
= (HEADER
*) answer
;
342 char tmp
[NS_MAXDNAME
];
344 int trailing_dot
, ret
, saved_herrno
;
345 int got_nodata
= 0, got_servfail
= 0, root_on_list
= 0;
350 RES_SET_H_ERRNO(statp
, HOST_NOT_FOUND
); /* True if we never query. */
353 for (cp
= name
; *cp
!= '\0'; cp
++)
354 dots
+= (*cp
== '.');
356 if (cp
> name
&& *--cp
== '.')
359 /* If there aren't any dots, it could be a user-level alias. */
360 if (!dots
&& (cp
= res_hostalias(statp
, name
, tmp
, sizeof tmp
))!= NULL
)
361 return (__libc_res_nquery(statp
, cp
, class, type
, answer
,
362 anslen
, answerp
, answerp2
,
363 nanswerp2
, resplen2
, answerp2_malloced
));
366 if (statp
->options
& RES_DEBUG
)
367 printf("dots=%d, statp->ndots=%d, trailing_dot=%d, name=%s\n",
368 (int)dots
,(int)statp
->ndots
,(int)trailing_dot
,name
);
372 * If there are enough dots in the name, let's just give it a
373 * try 'as is'. The threshold can be set with the "ndots" option.
374 * Also, query 'as is', if there is a trailing dot in the name.
377 if (dots
>= statp
->ndots
|| trailing_dot
) {
378 ret
= __libc_res_nquerydomain(statp
, name
, NULL
, class, type
,
379 answer
, anslen
, answerp
,
380 answerp2
, nanswerp2
, resplen2
,
382 if (ret
> 0 || trailing_dot
383 /* If the second response is valid then we use that. */
384 || (ret
== 0 && resplen2
!= NULL
&& *resplen2
> 0))
386 saved_herrno
= h_errno
;
388 if (answerp
&& *answerp
!= answer
) {
392 if (answerp2
&& *answerp2_malloced
)
397 *answerp2_malloced
= 0;
402 * We do at least one level of search if
403 * - there is no dot and RES_DEFNAME is set, or
404 * - there is at least one dot, there is no trailing dot,
405 * and RES_DNSRCH is set.
407 if ((!dots
&& (statp
->options
& RES_DEFNAMES
) != 0) ||
408 (dots
&& !trailing_dot
&& (statp
->options
& RES_DNSRCH
) != 0)) {
411 for (domain
= (const char * const *)statp
->dnsrch
;
414 const char *dname
= domain
[0];
417 /* __libc_res_nquerydoman concatenates name
418 with dname with a "." in between. If we
419 pass it in dname the "." we got from the
420 configured default search path, we'll end
421 up with "name..", which won't resolve.
422 OTOH, passing it "" will result in "name.",
423 which has the intended effect for both
424 possible representations of the root
428 if (dname
[0] == '\0')
431 ret
= __libc_res_nquerydomain(statp
, name
, dname
,
433 answer
, anslen
, answerp
,
435 resplen2
, answerp2_malloced
);
436 if (ret
> 0 || (ret
== 0 && resplen2
!= NULL
440 if (answerp
&& *answerp
!= answer
) {
444 if (answerp2
&& *answerp2_malloced
)
449 *answerp2_malloced
= 0;
453 * If no server present, give up.
454 * If name isn't found in this domain,
455 * keep trying higher domains in the search list
456 * (if that's enabled).
457 * On a NO_DATA error, keep trying, otherwise
458 * a wildcard entry of another type could keep us
459 * from finding this entry higher in the domain.
460 * If we get some other error (negative answer or
461 * server failure), then stop searching up,
462 * but try the input name below in case it's
465 if (errno
== ECONNREFUSED
) {
466 RES_SET_H_ERRNO(statp
, TRY_AGAIN
);
470 switch (statp
->res_h_errno
) {
478 if (hp
->rcode
== SERVFAIL
) {
479 /* try next search element, if any */
485 /* anything else implies that we're done */
489 /* if we got here for some reason other than DNSRCH,
490 * we only wanted one iteration of the loop, so stop.
492 if ((statp
->options
& RES_DNSRCH
) == 0)
498 * If the query has not already been tried as is then try it
499 * unless RES_NOTLDQUERY is set and there were no dots.
501 if ((dots
|| !searched
|| (statp
->options
& RES_NOTLDQUERY
) == 0)
502 && !(tried_as_is
|| root_on_list
)) {
503 ret
= __libc_res_nquerydomain(statp
, name
, NULL
, class, type
,
504 answer
, anslen
, answerp
,
505 answerp2
, nanswerp2
, resplen2
,
507 if (ret
> 0 || (ret
== 0 && resplen2
!= NULL
512 /* if we got here, we didn't satisfy the search.
513 * if we did an initial full query, return that query's H_ERRNO
514 * (note that we wouldn't be here if that query had succeeded).
515 * else if we ever got a nodata, send that back as the reason.
516 * else send back meaningless H_ERRNO, that being the one from
517 * the last DNSRCH we did.
519 if (answerp2
&& *answerp2_malloced
)
524 *answerp2_malloced
= 0;
526 if (saved_herrno
!= -1)
527 RES_SET_H_ERRNO(statp
, saved_herrno
);
529 RES_SET_H_ERRNO(statp
, NO_DATA
);
530 else if (got_servfail
)
531 RES_SET_H_ERRNO(statp
, TRY_AGAIN
);
534 libresolv_hidden_def (__libc_res_nsearch
)
537 res_nsearch(res_state statp
,
538 const char *name
, /* domain name */
539 int class, int type
, /* class and type of query */
540 u_char
*answer
, /* buffer to put answer */
541 int anslen
) /* size of answer */
543 return __libc_res_nsearch(statp
, name
, class, type
, answer
,
544 anslen
, NULL
, NULL
, NULL
, NULL
, NULL
);
546 libresolv_hidden_def (res_nsearch
)
549 * Perform a call on res_query on the concatenation of name and domain.
552 __libc_res_nquerydomain(res_state statp
,
555 int class, int type
, /* class and type of query */
556 u_char
*answer
, /* buffer to put answer */
557 int anslen
, /* size of answer */
562 int *answerp2_malloced
)
565 const char *longname
= nbuf
;
569 if (statp
->options
& RES_DEBUG
)
570 printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
571 name
, domain
?domain
:"<Nil>", class, type
);
573 if (domain
== NULL
) {
576 /* Decrement N prior to checking it against MAXDNAME
577 so that we detect a wrap to SIZE_MAX and return
578 a reasonable error. */
580 if (n
>= MAXDNAME
- 1) {
581 RES_SET_H_ERRNO(statp
, NO_RECOVERY
);
588 if (n
+ d
+ 1 >= MAXDNAME
) {
589 RES_SET_H_ERRNO(statp
, NO_RECOVERY
);
592 sprintf(nbuf
, "%s.%s", name
, domain
);
594 return (__libc_res_nquery(statp
, longname
, class, type
, answer
,
595 anslen
, answerp
, answerp2
, nanswerp2
,
596 resplen2
, answerp2_malloced
));
600 res_nquerydomain(res_state statp
,
603 int class, int type
, /* class and type of query */
604 u_char
*answer
, /* buffer to put answer */
605 int anslen
) /* size of answer */
607 return __libc_res_nquerydomain(statp
, name
, domain
, class, type
,
608 answer
, anslen
, NULL
, NULL
, NULL
, NULL
,
611 libresolv_hidden_def (res_nquerydomain
)
614 res_hostalias(const res_state statp
, const char *name
, char *dst
, size_t siz
) {
615 char *file
, *cp1
, *cp2
;
619 if (statp
->options
& RES_NOALIASES
)
621 file
= getenv("HOSTALIASES");
622 if (file
== NULL
|| (fp
= fopen(file
, "rce")) == NULL
)
625 buf
[sizeof(buf
) - 1] = '\0';
626 while (fgets(buf
, sizeof(buf
), fp
)) {
627 for (cp1
= buf
; *cp1
&& !isspace(*cp1
); ++cp1
)
632 if (ns_samename(buf
, name
) == 1) {
633 while (isspace(*++cp1
))
637 for (cp2
= cp1
+ 1; *cp2
&& !isspace(*cp2
); ++cp2
)
640 strncpy(dst
, cp1
, siz
- 1);
649 libresolv_hidden_def (res_hostalias
)