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source: rtems-libbsd/freebsd/lib/libc/resolv/res_findzonecut.c @ 66659ff

4.1155-freebsd-126-freebsd-12freebsd-9.3

Last change on this file since 66659ff was d48955b, checked in by Sebastian Huber <sebastian.huber@…>, on 11/06/13 at 08:02:16
Add and use <machine/rtems-bsd-user-space.h>
Property mode set to `100644`
File size: 18.3 KB

Line
1	#include <machine/rtems-bsd-user-space.h>
2
3	#if !defined(lint) && !defined(SABER)
4	static const char rcsid[] = "$Id: res_findzonecut.c,v 1.7.18.3 2005/10/11 00:25:11 marka Exp $";
5	#endif /* not lint */
6
7	/*
8	* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
9	* Copyright (c) 1999 by Internet Software Consortium.
10	*
11	* Permission to use, copy, modify, and distribute this software for any
12	* purpose with or without fee is hereby granted, provided that the above
13	* copyright notice and this permission notice appear in all copies.
14	*
15	* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
16	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
17	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
18	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
19	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
20	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
21	* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
22	*/
23
24	#include <sys/cdefs.h>
25	__FBSDID("$FreeBSD$");
26
27	/* Import. */
28
29	#include "port_before.h"
30
31	#include <rtems/bsd/sys/param.h>
32	#include <sys/socket.h>
33	#include <rtems/bsd/sys/time.h>
34
35	#include <netinet/in.h>
36	#include <arpa/inet.h>
37	#include <arpa/nameser.h>
38
39	#include <errno.h>
40	#include <limits.h>
41	#include <netdb.h>
42	#include <stdarg.h>
43	#include <stdio.h>
44	#include <stdlib.h>
45	#include <string.h>
46
47	#include <isc/list.h>
48
49	#include "port_after.h"
50
51	#include <resolv.h>
52
53	/* Data structures. */
54
55	typedef struct rr_a {
56	LINK(struct rr_a) link;
57	union res_sockaddr_union addr;
58	} rr_a;
59	typedef LIST(rr_a) rrset_a;
60
61	typedef struct rr_ns {
62	LINK(struct rr_ns) link;
63	const char * name;
64	unsigned int flags;
65	rrset_a addrs;
66	} rr_ns;
67	typedef LIST(rr_ns) rrset_ns;
68
69	#define RR_NS_HAVE_V4 0x01
70	#define RR_NS_HAVE_V6 0x02
71
72	/* Forward. */
73
74	static int satisfy(res_state, const char , rrset_ns ,
75	union res_sockaddr_union *, int);
76	static int add_addrs(res_state, rr_ns *,
77	union res_sockaddr_union *, int);
78	static int get_soa(res_state, const char *, ns_class, int,
79	char , size_t, char , size_t,
80	rrset_ns *);
81	static int get_ns(res_state, const char , ns_class, int, rrset_ns );
82	static int get_glue(res_state, ns_class, int, rrset_ns *);
83	static int save_ns(res_state, ns_msg *, ns_sect,
84	const char , ns_class, int, rrset_ns );
85	static int save_a(res_state, ns_msg *, ns_sect,
86	const char , ns_class, int, rr_ns );
87	static void free_nsrrset(rrset_ns *);
88	static void free_nsrr(rrset_ns , rr_ns );
89	static rr_ns * find_ns(rrset_ns , const char );
90	static int do_query(res_state, const char *, ns_class, ns_type,
91	u_char , ns_msg );
92	static void res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2);
93
94	/* Macros. */
95
96	#define DPRINTF(x) do {\
97	int save_errno = errno; \
98	if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \
99	errno = save_errno; \
100	} while (0)
101
102	/* Public. */
103
104	/*%
105	* find enclosing zone for a <dname,class>, and some server addresses
106	*
107	* parameters:
108	*\li res - resolver context to work within (is modified)
109	*\li dname - domain name whose enclosing zone is desired
110	*\li class - class of dname (and its enclosing zone)
111	*\li zname - found zone name
112	*\li zsize - allocated size of zname
113	*\li addrs - found server addresses
114	*\li naddrs - max number of addrs
115	*
116	* return values:
117	*\li < 0 - an error occurred (check errno)
118	*\li = 0 - zname is now valid, but addrs[] wasn't changed
119	*\li > 0 - zname is now valid, and return value is number of addrs[] found
120	*
121	* notes:
122	*\li this function calls res_nsend() which means it depends on correctly
123	* functioning recursive nameservers (usually defined in /etc/resolv.conf
124	* or its local equivilent).
125	*
126	*\li we start by asking for an SOA<dname,class>. if we get one as an
127	* answer, that just means <dname,class> is a zone top, which is fine.
128	* more than likely we'll be told to go pound sand, in the form of a
129	* negative answer.
130	*
131	*\li note that we are not prepared to deal with referrals since that would
132	* only come from authority servers and our correctly functioning local
133	* recursive server would have followed the referral and got us something
134	* more definite.
135	*
136	*\li if the authority section contains an SOA, this SOA should also be the
137	* closest enclosing zone, since any intermediary zone cuts would've been
138	* returned as referrals and dealt with by our correctly functioning local
139	* recursive name server. but an SOA in the authority section should NOT
140	* match our dname (since that would have been returned in the answer
141	* section). an authority section SOA has to be "above" our dname.
142	*
143	*\li however, since authority section SOA's were once optional, it's
144	* possible that we'll have to go hunting for the enclosing SOA by
145	* ripping labels off the front of our dname -- this is known as "doing
146	* it the hard way."
147	*
148	*\li ultimately we want some server addresses, which are ideally the ones
149	* pertaining to the SOA.MNAME, but only if there is a matching NS RR.
150	* so the second phase (after we find an SOA) is to go looking for the
151	* NS RRset for that SOA's zone.
152	*
153	*\li no answer section processed by this code is allowed to contain CNAME
154	* or DNAME RR's. for the SOA query this means we strip a label and
155	* keep going. for the NS and A queries this means we just give up.
156	*/
157
158	#ifndef _LIBC
159	int
160	res_findzonecut(res_state statp, const char *dname, ns_class class, int opts,
161	char zname, size_t zsize, struct in_addr addrs, int naddrs)
162	{
163	int result, i;
164	union res_sockaddr_union *u;
165
166
167	opts \|= RES_IPV4ONLY;
168	opts &= ~RES_IPV6ONLY;
169
170	u = calloc(naddrs, sizeof(*u));
171	if (u == NULL)
172	return(-1);
173
174	result = res_findzonecut2(statp, dname, class, opts, zname, zsize,
175	u, naddrs);
176
177	for (i = 0; i < result; i++) {
178	addrs[i] = u[i].sin.sin_addr;
179	}
180	free(u);
181	return (result);
182	}
183	#endif
184
185	int
186	res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts,
187	char zname, size_t zsize, union res_sockaddr_union addrs,
188	int naddrs)
189	{
190	char mname[NS_MAXDNAME];
191	u_long save_pfcode;
192	rrset_ns nsrrs;
193	int n;
194
195	DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d",
196	dname, p_class(class), (long)zsize, naddrs));
197	save_pfcode = statp->pfcode;
198	statp->pfcode \|= RES_PRF_HEAD2 \| RES_PRF_HEAD1 \| RES_PRF_HEADX \|
199	RES_PRF_QUES \| RES_PRF_ANS \|
200	RES_PRF_AUTH \| RES_PRF_ADD;
201	INIT_LIST(nsrrs);
202
203	DPRINTF(("get the soa, and see if it has enough glue"));
204	if ((n = get_soa(statp, dname, class, opts, zname, zsize,
205	mname, sizeof mname, &nsrrs)) < 0 \|\|
206	((opts & RES_EXHAUSTIVE) == 0 &&
207	(n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
208	goto done;
209
210	DPRINTF(("get the ns rrset and see if it has enough glue"));
211	if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 \|\|
212	((opts & RES_EXHAUSTIVE) == 0 &&
213	(n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
214	goto done;
215
216	DPRINTF(("get the missing glue and see if it's finally enough"));
217	if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0)
218	n = satisfy(statp, mname, &nsrrs, addrs, naddrs);
219
220	done:
221	DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK"));
222	free_nsrrset(&nsrrs);
223	statp->pfcode = save_pfcode;
224	return (n);
225	}
226
227	/* Private. */
228
229	static int
230	satisfy(res_state statp, const char mname, rrset_ns nsrrsp,
231	union res_sockaddr_union *addrs, int naddrs)
232	{
233	rr_ns *nsrr;
234	int n, x;
235
236	n = 0;
237	nsrr = find_ns(nsrrsp, mname);
238	if (nsrr != NULL) {
239	x = add_addrs(statp, nsrr, addrs, naddrs);
240	addrs += x;
241	naddrs -= x;
242	n += x;
243	}
244	for (nsrr = HEAD(*nsrrsp);
245	nsrr != NULL && naddrs > 0;
246	nsrr = NEXT(nsrr, link))
247	if (ns_samename(nsrr->name, mname) != 1) {
248	x = add_addrs(statp, nsrr, addrs, naddrs);
249	addrs += x;
250	naddrs -= x;
251	n += x;
252	}
253	DPRINTF(("satisfy(%s): %d", mname, n));
254	return (n);
255	}
256
257	static int
258	add_addrs(res_state statp, rr_ns *nsrr,
259	union res_sockaddr_union *addrs, int naddrs)
260	{
261	rr_a *arr;
262	int n = 0;
263
264	for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) {
265	if (naddrs <= 0)
266	return (0);
267	*addrs++ = arr->addr;
268	naddrs--;
269	n++;
270	}
271	DPRINTF(("add_addrs: %d", n));
272	return (n);
273	}
274
275	static int
276	get_soa(res_state statp, const char *dname, ns_class class, int opts,
277	char zname, size_t zsize, char mname, size_t msize,
278	rrset_ns *nsrrsp)
279	{
280	char tname[NS_MAXDNAME];
281	u_char *resp = NULL;
282	int n, i, ancount, nscount;
283	ns_sect sect;
284	ns_msg msg;
285	u_int rcode;
286
287	/*
288	* Find closest enclosing SOA, even if it's for the root zone.
289	*/
290
291	/* First canonicalize dname (exactly one unescaped trailing "."). */
292	if (ns_makecanon(dname, tname, sizeof tname) < 0)
293	goto cleanup;
294	dname = tname;
295
296	resp = malloc(NS_MAXMSG);
297	if (resp == NULL)
298	goto cleanup;
299
300	/* Now grovel the subdomains, hunting for an SOA answer or auth. */
301	for (;;) {
302	/* Leading or inter-label '.' are skipped here. */
303	while (*dname == '.')
304	dname++;
305
306	/* Is there an SOA? */
307	n = do_query(statp, dname, class, ns_t_soa, resp, &msg);
308	if (n < 0) {
309	DPRINTF(("get_soa: do_query('%s', %s) failed (%d)",
310	dname, p_class(class), n));
311	goto cleanup;
312	}
313	if (n > 0) {
314	DPRINTF(("get_soa: CNAME or DNAME found"));
315	sect = ns_s_max, n = 0;
316	} else {
317	rcode = ns_msg_getflag(msg, ns_f_rcode);
318	ancount = ns_msg_count(msg, ns_s_an);
319	nscount = ns_msg_count(msg, ns_s_ns);
320	if (ancount > 0 && rcode == ns_r_noerror)
321	sect = ns_s_an, n = ancount;
322	else if (nscount > 0)
323	sect = ns_s_ns, n = nscount;
324	else
325	sect = ns_s_max, n = 0;
326	}
327	for (i = 0; i < n; i++) {
328	const char *t;
329	const u_char *rdata;
330	ns_rr rr;
331
332	if (ns_parserr(&msg, sect, i, &rr) < 0) {
333	DPRINTF(("get_soa: ns_parserr(%s, %d) failed",
334	p_section(sect, ns_o_query), i));
335	goto cleanup;
336	}
337	if (ns_rr_type(rr) == ns_t_cname \|\|
338	ns_rr_type(rr) == ns_t_dname)
339	break;
340	if (ns_rr_type(rr) != ns_t_soa \|\|
341	ns_rr_class(rr) != class)
342	continue;
343	t = ns_rr_name(rr);
344	switch (sect) {
345	case ns_s_an:
346	if (ns_samedomain(dname, t) == 0) {
347	DPRINTF(
348	("get_soa: ns_samedomain('%s', '%s') == 0",
349	dname, t)
350	);
351	errno = EPROTOTYPE;
352	goto cleanup;
353	}
354	break;
355	case ns_s_ns:
356	if (ns_samename(dname, t) == 1 \|\|
357	ns_samedomain(dname, t) == 0) {
358	DPRINTF(
359	("get_soa: ns_samename() \|\| !ns_samedomain('%s', '%s')",
360	dname, t)
361	);
362	errno = EPROTOTYPE;
363	goto cleanup;
364	}
365	break;
366	default:
367	abort();
368	}
369	if (strlen(t) + 1 > zsize) {
370	DPRINTF(("get_soa: zname(%lu) too small (%lu)",
371	(unsigned long)zsize,
372	(unsigned long)strlen(t) + 1));
373	errno = EMSGSIZE;
374	goto cleanup;
375	}
376	strcpy(zname, t);
377	rdata = ns_rr_rdata(rr);
378	if (ns_name_uncompress(resp, ns_msg_end(msg), rdata,
379	mname, msize) < 0) {
380	DPRINTF(("get_soa: ns_name_uncompress failed")
381	);
382	goto cleanup;
383	}
384	if (save_ns(statp, &msg, ns_s_ns,
385	zname, class, opts, nsrrsp) < 0) {
386	DPRINTF(("get_soa: save_ns failed"));
387	goto cleanup;
388	}
389	free(resp);
390	return (0);
391	}
392
393	/* If we're out of labels, then not even "." has an SOA! */
394	if (*dname == '\0')
395	break;
396
397	/* Find label-terminating "."; top of loop will skip it. */
398	while (*dname != '.') {
399	if (*dname == '\\')
400	if (*++dname == '\0') {
401	errno = EMSGSIZE;
402	goto cleanup;
403	}
404	dname++;
405	}
406	}
407	DPRINTF(("get_soa: out of labels"));
408	errno = EDESTADDRREQ;
409	cleanup:
410	if (resp != NULL)
411	free(resp);
412	return (-1);
413	}
414
415	static int
416	get_ns(res_state statp, const char *zname, ns_class class, int opts,
417	rrset_ns *nsrrsp)
418	{
419	u_char *resp;
420	ns_msg msg;
421	int n;
422
423	resp = malloc(NS_MAXMSG);
424	if (resp == NULL)
425	return (-1);
426
427	/* Go and get the NS RRs for this zone. */
428	n = do_query(statp, zname, class, ns_t_ns, resp, &msg);
429	if (n != 0) {
430	DPRINTF(("get_ns: do_query('%s', %s) failed (%d)",
431	zname, p_class(class), n));
432	free(resp);
433	return (-1);
434	}
435
436	/* Remember the NS RRs and associated A RRs that came back. */
437	if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) {
438	DPRINTF(("get_ns save_ns('%s', %s) failed",
439	zname, p_class(class)));
440	free(resp);
441	return (-1);
442	}
443
444	free(resp);
445	return (0);
446	}
447
448	static int
449	get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) {
450	rr_ns nsrr, nsrr_n;
451	u_char *resp;
452
453	resp = malloc(NS_MAXMSG);
454	if (resp == NULL)
455	return(-1);
456
457	/* Go and get the A RRs for each empty NS RR on our list. */
458	for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) {
459	ns_msg msg;
460	int n;
461
462	nsrr_n = NEXT(nsrr, link);
463
464	if ((nsrr->flags & RR_NS_HAVE_V4) == 0) {
465	n = do_query(statp, nsrr->name, class, ns_t_a,
466	resp, &msg);
467	if (n < 0) {
468	DPRINTF(
469	("get_glue: do_query('%s', %s') failed",
470	nsrr->name, p_class(class)));
471	goto cleanup;
472	}
473	if (n > 0) {
474	DPRINTF((
475	"get_glue: do_query('%s', %s') CNAME or DNAME found",
476	nsrr->name, p_class(class)));
477	}
478	if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
479	opts, nsrr) < 0) {
480	DPRINTF(("get_glue: save_r('%s', %s) failed",
481	nsrr->name, p_class(class)));
482	goto cleanup;
483	}
484	}
485
486	if ((nsrr->flags & RR_NS_HAVE_V6) == 0) {
487	n = do_query(statp, nsrr->name, class, ns_t_aaaa,
488	resp, &msg);
489	if (n < 0) {
490	DPRINTF(
491	("get_glue: do_query('%s', %s') failed",
492	nsrr->name, p_class(class)));
493	goto cleanup;
494	}
495	if (n > 0) {
496	DPRINTF((
497	"get_glue: do_query('%s', %s') CNAME or DNAME found",
498	nsrr->name, p_class(class)));
499	}
500	if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
501	opts, nsrr) < 0) {
502	DPRINTF(("get_glue: save_r('%s', %s) failed",
503	nsrr->name, p_class(class)));
504	goto cleanup;
505	}
506	}
507
508	/* If it's still empty, it's just chaff. */
509	if (EMPTY(nsrr->addrs)) {
510	DPRINTF(("get_glue: removing empty '%s' NS",
511	nsrr->name));
512	free_nsrr(nsrrsp, nsrr);
513	}
514	}
515	free(resp);
516	return (0);
517
518	cleanup:
519	free(resp);
520	return (-1);
521	}
522
523	static int
524	save_ns(res_state statp, ns_msg *msg, ns_sect sect,
525	const char *owner, ns_class class, int opts,
526	rrset_ns *nsrrsp)
527	{
528	int i;
529
530	for (i = 0; i < ns_msg_count(*msg, sect); i++) {
531	char tname[MAXDNAME];
532	const u_char *rdata;
533	rr_ns *nsrr;
534	ns_rr rr;
535
536	if (ns_parserr(msg, sect, i, &rr) < 0) {
537	DPRINTF(("save_ns: ns_parserr(%s, %d) failed",
538	p_section(sect, ns_o_query), i));
539	return (-1);
540	}
541	if (ns_rr_type(rr) != ns_t_ns \|\|
542	ns_rr_class(rr) != class \|\|
543	ns_samename(ns_rr_name(rr), owner) != 1)
544	continue;
545	nsrr = find_ns(nsrrsp, ns_rr_name(rr));
546	if (nsrr == NULL) {
547	nsrr = malloc(sizeof *nsrr);
548	if (nsrr == NULL) {
549	DPRINTF(("save_ns: malloc failed"));
550	return (-1);
551	}
552	rdata = ns_rr_rdata(rr);
553	if (ns_name_uncompress(ns_msg_base(*msg),
554	ns_msg_end(*msg), rdata,
555	tname, sizeof tname) < 0) {
556	DPRINTF(("save_ns: ns_name_uncompress failed")
557	);
558	free(nsrr);
559	return (-1);
560	}
561	nsrr->name = strdup(tname);
562	if (nsrr->name == NULL) {
563	DPRINTF(("save_ns: strdup failed"));
564	free(nsrr);
565	return (-1);
566	}
567	INIT_LINK(nsrr, link);
568	INIT_LIST(nsrr->addrs);
569	nsrr->flags = 0;
570	APPEND(*nsrrsp, nsrr, link);
571	}
572	if (save_a(statp, msg, ns_s_ar,
573	nsrr->name, class, opts, nsrr) < 0) {
574	DPRINTF(("save_ns: save_r('%s', %s) failed",
575	nsrr->name, p_class(class)));
576	return (-1);
577	}
578	}
579	return (0);
580	}
581
582	static int
583	save_a(res_state statp, ns_msg *msg, ns_sect sect,
584	const char *owner, ns_class class, int opts,
585	rr_ns *nsrr)
586	{
587	int i;
588
589	for (i = 0; i < ns_msg_count(*msg, sect); i++) {
590	ns_rr rr;
591	rr_a *arr;
592
593	if (ns_parserr(msg, sect, i, &rr) < 0) {
594	DPRINTF(("save_a: ns_parserr(%s, %d) failed",
595	p_section(sect, ns_o_query), i));
596	return (-1);
597	}
598	if ((ns_rr_type(rr) != ns_t_a &&
599	ns_rr_type(rr) != ns_t_aaaa) \|\|
600	ns_rr_class(rr) != class \|\|
601	ns_samename(ns_rr_name(rr), owner) != 1 \|\|
602	ns_rr_rdlen(rr) != NS_INADDRSZ)
603	continue;
604	if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa)
605	continue;
606	if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a)
607	continue;
608	arr = malloc(sizeof *arr);
609	if (arr == NULL) {
610	DPRINTF(("save_a: malloc failed"));
611	return (-1);
612	}
613	INIT_LINK(arr, link);
614	memset(&arr->addr, 0, sizeof(arr->addr));
615	switch (ns_rr_type(rr)) {
616	case ns_t_a:
617	arr->addr.sin.sin_family = AF_INET;
618	#ifdef HAVE_SA_LEN
619	arr->addr.sin.sin_len = sizeof(arr->addr.sin);
620	#endif
621	memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr),
622	NS_INADDRSZ);
623	arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
624	nsrr->flags \|= RR_NS_HAVE_V4;
625	break;
626	case ns_t_aaaa:
627	arr->addr.sin6.sin6_family = AF_INET6;
628	#ifdef HAVE_SA_LEN
629	arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6);
630	#endif
631	memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16);
632	arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
633	nsrr->flags \|= RR_NS_HAVE_V6;
634	break;
635	default:
636	abort();
637	}
638	APPEND(nsrr->addrs, arr, link);
639	}
640	return (0);
641	}
642
643	static void
644	free_nsrrset(rrset_ns *nsrrsp) {
645	rr_ns *nsrr;
646
647	while ((nsrr = HEAD(*nsrrsp)) != NULL)
648	free_nsrr(nsrrsp, nsrr);
649	}
650
651	static void
652	free_nsrr(rrset_ns nsrrsp, rr_ns nsrr) {
653	rr_a *arr;
654	char *tmp;
655
656	while ((arr = HEAD(nsrr->addrs)) != NULL) {
657	UNLINK(nsrr->addrs, arr, link);
658	free(arr);
659	}
660	DE_CONST(nsrr->name, tmp);
661	free(tmp);
662	UNLINK(*nsrrsp, nsrr, link);
663	free(nsrr);
664	}
665
666	static rr_ns *
667	find_ns(rrset_ns nsrrsp, const char dname) {
668	rr_ns *nsrr;
669
670	for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link))
671	if (ns_samename(nsrr->name, dname) == 1)
672	return (nsrr);
673	return (NULL);
674	}
675
676	static int
677	do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
678	u_char resp, ns_msg msg)
679	{
680	u_char req[NS_PACKETSZ];
681	int i, n;
682
683	n = res_nmkquery(statp, ns_o_query, dname, class, qtype,
684	NULL, 0, NULL, req, NS_PACKETSZ);
685	if (n < 0) {
686	DPRINTF(("do_query: res_nmkquery failed"));
687	return (-1);
688	}
689	n = res_nsend(statp, req, n, resp, NS_MAXMSG);
690	if (n < 0) {
691	DPRINTF(("do_query: res_nsend failed"));
692	return (-1);
693	}
694	if (n == 0) {
695	DPRINTF(("do_query: res_nsend returned 0"));
696	errno = EMSGSIZE;
697	return (-1);
698	}
699	if (ns_initparse(resp, n, msg) < 0) {
700	DPRINTF(("do_query: ns_initparse failed"));
701	return (-1);
702	}
703	n = 0;
704	for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
705	ns_rr rr;
706
707	if (ns_parserr(msg, ns_s_an, i, &rr) < 0) {
708	DPRINTF(("do_query: ns_parserr failed"));
709	return (-1);
710	}
711	n += (ns_rr_class(rr) == class &&
712	(ns_rr_type(rr) == ns_t_cname \|\|
713	ns_rr_type(rr) == ns_t_dname));
714	}
715	return (n);
716	}
717
718	static void
719	res_dprintf(const char *fmt, ...) {
720	va_list ap;
721
722	va_start(ap, fmt);
723	fputs(";; res_findzonecut: ", stderr);
724	vfprintf(stderr, fmt, ap);
725	fputc('\n', stderr);
726	va_end(ap);
727	}
728
729	/! \file /

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