1#if !defined(lint) && !defined(SABER)
2static const char rcsid[] = "$Id: res_findzonecut.c,v 1.10 2005/10/11 00:10:16 marka Exp $";
3#endif /* not lint */
4
5/*
6 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
7 * Copyright (c) 1999 by Internet Software Consortium.
8 *
9 * Permission to use, copy, modify, and distribute this software for any
10 * purpose with or without fee is hereby granted, provided that the above
11 * copyright notice and this permission notice appear in all copies.
12 *
13 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
14 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
15 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
16 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
17 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
18 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
19 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
20 */
21
22#include <sys/cdefs.h>
23__FBSDID("$FreeBSD$");
24
25/* Import. */
26
27#include "port_before.h"
28
29#include <sys/param.h>
30#include <sys/socket.h>
31#include <sys/time.h>
32
33#include <netinet/in.h>
34#include <arpa/inet.h>
35#include <arpa/nameser.h>
36
37#include <errno.h>
38#include <limits.h>
39#include <netdb.h>
40#include <stdarg.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44
45#include <isc/list.h>
46
47#include "port_after.h"
48
49#include <resolv.h>
50
51/* Data structures. */
52
53typedef struct rr_a {
54	LINK(struct rr_a)	link;
55	union res_sockaddr_union addr;
56} rr_a;
57typedef LIST(rr_a) rrset_a;
58
59typedef struct rr_ns {
60	LINK(struct rr_ns)	link;
61	const char *		name;
62	unsigned int		flags;
63	rrset_a			addrs;
64} rr_ns;
65typedef LIST(rr_ns) rrset_ns;
66
67#define	RR_NS_HAVE_V4		0x01
68#define	RR_NS_HAVE_V6		0x02
69
70/* Forward. */
71
72static int	satisfy(res_state, const char *, rrset_ns *,
73			union res_sockaddr_union *, int);
74static int	add_addrs(res_state, rr_ns *,
75			  union res_sockaddr_union *, int);
76static int	get_soa(res_state, const char *, ns_class, int,
77			char *, size_t, char *, size_t,
78			rrset_ns *);
79static int	get_ns(res_state, const char *, ns_class, int, rrset_ns *);
80static int	get_glue(res_state, ns_class, int, rrset_ns *);
81static int	save_ns(res_state, ns_msg *, ns_sect,
82			const char *, ns_class, int, rrset_ns *);
83static int	save_a(res_state, ns_msg *, ns_sect,
84		       const char *, ns_class, int, rr_ns *);
85static void	free_nsrrset(rrset_ns *);
86static void	free_nsrr(rrset_ns *, rr_ns *);
87static rr_ns *	find_ns(rrset_ns *, const char *);
88static int	do_query(res_state, const char *, ns_class, ns_type,
89			 u_char *, ns_msg *);
90static void	res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2);
91
92/* Macros. */
93
94#define DPRINTF(x) do {\
95		int save_errno = errno; \
96		if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \
97		errno = save_errno; \
98	} while (0)
99
100/* Public. */
101
102/*%
103 *	find enclosing zone for a <dname,class>, and some server addresses
104 *
105 * parameters:
106 *\li	res - resolver context to work within (is modified)
107 *\li	dname - domain name whose enclosing zone is desired
108 *\li	class - class of dname (and its enclosing zone)
109 *\li	zname - found zone name
110 *\li	zsize - allocated size of zname
111 *\li	addrs - found server addresses
112 *\li	naddrs - max number of addrs
113 *
114 * return values:
115 *\li	< 0 - an error occurred (check errno)
116 *\li	= 0 - zname is now valid, but addrs[] wasn't changed
117 *\li	> 0 - zname is now valid, and return value is number of addrs[] found
118 *
119 * notes:
120 *\li	this function calls res_nsend() which means it depends on correctly
121 *	functioning recursive nameservers (usually defined in /etc/resolv.conf
122 *	or its local equivalent).
123 *
124 *\li	we start by asking for an SOA<dname,class>.  if we get one as an
125 *	answer, that just means <dname,class> is a zone top, which is fine.
126 *	more than likely we'll be told to go pound sand, in the form of a
127 *	negative answer.
128 *
129 *\li	note that we are not prepared to deal with referrals since that would
130 *	only come from authority servers and our correctly functioning local
131 *	recursive server would have followed the referral and got us something
132 *	more definite.
133 *
134 *\li	if the authority section contains an SOA, this SOA should also be the
135 *	closest enclosing zone, since any intermediary zone cuts would've been
136 *	returned as referrals and dealt with by our correctly functioning local
137 *	recursive name server.  but an SOA in the authority section should NOT
138 *	match our dname (since that would have been returned in the answer
139 *	section).  an authority section SOA has to be "above" our dname.
140 *
141 *\li	however, since authority section SOA's were once optional, it's
142 *	possible that we'll have to go hunting for the enclosing SOA by
143 *	ripping labels off the front of our dname -- this is known as "doing
144 *	it the hard way."
145 *
146 *\li	ultimately we want some server addresses, which are ideally the ones
147 *	pertaining to the SOA.MNAME, but only if there is a matching NS RR.
148 *	so the second phase (after we find an SOA) is to go looking for the
149 *	NS RRset for that SOA's zone.
150 *
151 *\li	no answer section processed by this code is allowed to contain CNAME
152 *	or DNAME RR's.  for the SOA query this means we strip a label and
153 *	keep going.  for the NS and A queries this means we just give up.
154 */
155
156#ifndef _LIBC
157int
158res_findzonecut(res_state statp, const char *dname, ns_class class, int opts,
159		char *zname, size_t zsize, struct in_addr *addrs, int naddrs)
160{
161	int result, i;
162	union res_sockaddr_union *u;
163
164
165	opts |= RES_IPV4ONLY;
166	opts &= ~RES_IPV6ONLY;
167
168	u = calloc(naddrs, sizeof(*u));
169	if (u == NULL)
170		return(-1);
171
172	result = res_findzonecut2(statp, dname, class, opts, zname, zsize,
173				  u, naddrs);
174
175	for (i = 0; i < result; i++) {
176		addrs[i] = u[i].sin.sin_addr;
177	}
178	free(u);
179	return (result);
180}
181#endif
182
183int
184res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts,
185		 char *zname, size_t zsize, union res_sockaddr_union *addrs,
186		 int naddrs)
187{
188	char mname[NS_MAXDNAME];
189	u_long save_pfcode;
190	rrset_ns nsrrs;
191	int n;
192
193	DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d",
194		 dname, p_class(class), (long)zsize, naddrs));
195	save_pfcode = statp->pfcode;
196	statp->pfcode |= RES_PRF_HEAD2 | RES_PRF_HEAD1 | RES_PRF_HEADX |
197			 RES_PRF_QUES | RES_PRF_ANS |
198			 RES_PRF_AUTH | RES_PRF_ADD;
199	INIT_LIST(nsrrs);
200
201	DPRINTF(("get the soa, and see if it has enough glue"));
202	if ((n = get_soa(statp, dname, class, opts, zname, zsize,
203			 mname, sizeof mname, &nsrrs)) < 0 ||
204	    ((opts & RES_EXHAUSTIVE) == 0 &&
205	     (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
206		goto done;
207
208	DPRINTF(("get the ns rrset and see if it has enough glue"));
209	if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 ||
210	    ((opts & RES_EXHAUSTIVE) == 0 &&
211	     (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
212		goto done;
213
214	DPRINTF(("get the missing glue and see if it's finally enough"));
215	if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0)
216		n = satisfy(statp, mname, &nsrrs, addrs, naddrs);
217
218 done:
219	DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK"));
220	free_nsrrset(&nsrrs);
221	statp->pfcode = save_pfcode;
222	return (n);
223}
224
225/* Private. */
226
227static int
228satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp,
229	union res_sockaddr_union *addrs, int naddrs)
230{
231	rr_ns *nsrr;
232	int n, x;
233
234	n = 0;
235	nsrr = find_ns(nsrrsp, mname);
236	if (nsrr != NULL) {
237		x = add_addrs(statp, nsrr, addrs, naddrs);
238		addrs += x;
239		naddrs -= x;
240		n += x;
241	}
242	for (nsrr = HEAD(*nsrrsp);
243	     nsrr != NULL && naddrs > 0;
244	     nsrr = NEXT(nsrr, link))
245		if (ns_samename(nsrr->name, mname) != 1) {
246			x = add_addrs(statp, nsrr, addrs, naddrs);
247			addrs += x;
248			naddrs -= x;
249			n += x;
250		}
251	DPRINTF(("satisfy(%s): %d", mname, n));
252	return (n);
253}
254
255static int
256add_addrs(res_state statp, rr_ns *nsrr,
257	  union res_sockaddr_union *addrs, int naddrs)
258{
259	rr_a *arr;
260	int n = 0;
261
262	for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) {
263		if (naddrs <= 0)
264			return (0);
265		*addrs++ = arr->addr;
266		naddrs--;
267		n++;
268	}
269	DPRINTF(("add_addrs: %d", n));
270	return (n);
271}
272
273static int
274get_soa(res_state statp, const char *dname, ns_class class, int opts,
275	char *zname, size_t zsize, char *mname, size_t msize,
276	rrset_ns *nsrrsp)
277{
278	char tname[NS_MAXDNAME];
279	u_char *resp = NULL;
280	int n, i, ancount, nscount;
281	ns_sect sect;
282	ns_msg msg;
283	u_int rcode;
284
285	/*
286	 * Find closest enclosing SOA, even if it's for the root zone.
287	 */
288
289	/* First canonicalize dname (exactly one unescaped trailing "."). */
290	if (ns_makecanon(dname, tname, sizeof tname) < 0)
291		goto cleanup;
292	dname = tname;
293
294	resp = malloc(NS_MAXMSG);
295	if (resp == NULL)
296		goto cleanup;
297
298	/* Now grovel the subdomains, hunting for an SOA answer or auth. */
299	for (;;) {
300		/* Leading or inter-label '.' are skipped here. */
301		while (*dname == '.')
302			dname++;
303
304		/* Is there an SOA? */
305		n = do_query(statp, dname, class, ns_t_soa, resp, &msg);
306		if (n < 0) {
307			DPRINTF(("get_soa: do_query('%s', %s) failed (%d)",
308				 dname, p_class(class), n));
309			goto cleanup;
310		}
311		if (n > 0) {
312			DPRINTF(("get_soa: CNAME or DNAME found"));
313			sect = ns_s_max, n = 0;
314		} else {
315			rcode = ns_msg_getflag(msg, ns_f_rcode);
316			ancount = ns_msg_count(msg, ns_s_an);
317			nscount = ns_msg_count(msg, ns_s_ns);
318			if (ancount > 0 && rcode == ns_r_noerror)
319				sect = ns_s_an, n = ancount;
320			else if (nscount > 0)
321				sect = ns_s_ns, n = nscount;
322			else
323				sect = ns_s_max, n = 0;
324		}
325		for (i = 0; i < n; i++) {
326			const char *t;
327			const u_char *rdata;
328			ns_rr rr;
329
330			if (ns_parserr(&msg, sect, i, &rr) < 0) {
331				DPRINTF(("get_soa: ns_parserr(%s, %d) failed",
332					 p_section(sect, ns_o_query), i));
333				goto cleanup;
334			}
335			if (ns_rr_type(rr) == ns_t_cname ||
336			    ns_rr_type(rr) == ns_t_dname)
337				break;
338			if (ns_rr_type(rr) != ns_t_soa ||
339			    ns_rr_class(rr) != class)
340				continue;
341			t = ns_rr_name(rr);
342			switch (sect) {
343			case ns_s_an:
344				if (ns_samedomain(dname, t) == 0) {
345					DPRINTF(
346				    ("get_soa: ns_samedomain('%s', '%s') == 0",
347						dname, t)
348						);
349					errno = EPROTOTYPE;
350					goto cleanup;
351				}
352				break;
353			case ns_s_ns:
354				if (ns_samename(dname, t) == 1 ||
355				    ns_samedomain(dname, t) == 0) {
356					DPRINTF(
357		       ("get_soa: ns_samename() || !ns_samedomain('%s', '%s')",
358						dname, t)
359						);
360					errno = EPROTOTYPE;
361					goto cleanup;
362				}
363				break;
364			default:
365				abort();
366			}
367			if (strlen(t) + 1 > zsize) {
368				DPRINTF(("get_soa: zname(%lu) too small (%lu)",
369					 (unsigned long)zsize,
370					 (unsigned long)strlen(t) + 1));
371				errno = EMSGSIZE;
372				goto cleanup;
373			}
374			strcpy(zname, t);
375			rdata = ns_rr_rdata(rr);
376			if (ns_name_uncompress(resp, ns_msg_end(msg), rdata,
377					       mname, msize) < 0) {
378				DPRINTF(("get_soa: ns_name_uncompress failed")
379					);
380				goto cleanup;
381			}
382			if (save_ns(statp, &msg, ns_s_ns,
383				    zname, class, opts, nsrrsp) < 0) {
384				DPRINTF(("get_soa: save_ns failed"));
385				goto cleanup;
386			}
387			free(resp);
388			return (0);
389		}
390
391		/* If we're out of labels, then not even "." has an SOA! */
392		if (*dname == '\0')
393			break;
394
395		/* Find label-terminating "."; top of loop will skip it. */
396		while (*dname != '.') {
397			if (*dname == '\\')
398				if (*++dname == '\0') {
399					errno = EMSGSIZE;
400					goto cleanup;
401				}
402			dname++;
403		}
404	}
405	DPRINTF(("get_soa: out of labels"));
406	errno = EDESTADDRREQ;
407 cleanup:
408	if (resp != NULL)
409		free(resp);
410	return (-1);
411}
412
413static int
414get_ns(res_state statp, const char *zname, ns_class class, int opts,
415      rrset_ns *nsrrsp)
416{
417	u_char *resp;
418	ns_msg msg;
419	int n;
420
421	resp = malloc(NS_MAXMSG);
422	if (resp == NULL)
423		return (-1);
424
425	/* Go and get the NS RRs for this zone. */
426	n = do_query(statp, zname, class, ns_t_ns, resp, &msg);
427	if (n != 0) {
428		DPRINTF(("get_ns: do_query('%s', %s) failed (%d)",
429			 zname, p_class(class), n));
430		free(resp);
431		return (-1);
432	}
433
434	/* Remember the NS RRs and associated A RRs that came back. */
435	if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) {
436		DPRINTF(("get_ns save_ns('%s', %s) failed",
437			 zname, p_class(class)));
438		free(resp);
439		return (-1);
440	}
441
442	free(resp);
443	return (0);
444}
445
446static int
447get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) {
448	rr_ns *nsrr, *nsrr_n;
449	u_char *resp;
450
451	resp = malloc(NS_MAXMSG);
452	if (resp == NULL)
453		return(-1);
454
455	/* Go and get the A RRs for each empty NS RR on our list. */
456	for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) {
457		ns_msg msg;
458		int n;
459
460		nsrr_n = NEXT(nsrr, link);
461
462		if ((nsrr->flags & RR_NS_HAVE_V4) == 0) {
463			n = do_query(statp, nsrr->name, class, ns_t_a,
464				     resp, &msg);
465			if (n < 0) {
466				DPRINTF(
467				       ("get_glue: do_query('%s', %s') failed",
468					nsrr->name, p_class(class)));
469				goto cleanup;
470			}
471			if (n > 0) {
472				DPRINTF((
473			"get_glue: do_query('%s', %s') CNAME or DNAME found",
474					 nsrr->name, p_class(class)));
475			}
476			if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
477				   opts, nsrr) < 0) {
478				DPRINTF(("get_glue: save_r('%s', %s) failed",
479					 nsrr->name, p_class(class)));
480				goto cleanup;
481			}
482		}
483
484		if ((nsrr->flags & RR_NS_HAVE_V6) == 0) {
485			n = do_query(statp, nsrr->name, class, ns_t_aaaa,
486				     resp, &msg);
487			if (n < 0) {
488				DPRINTF(
489				       ("get_glue: do_query('%s', %s') failed",
490					nsrr->name, p_class(class)));
491				goto cleanup;
492			}
493			if (n > 0) {
494				DPRINTF((
495			"get_glue: do_query('%s', %s') CNAME or DNAME found",
496					 nsrr->name, p_class(class)));
497			}
498			if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
499				   opts, nsrr) < 0) {
500				DPRINTF(("get_glue: save_r('%s', %s) failed",
501					 nsrr->name, p_class(class)));
502				goto cleanup;
503			}
504		}
505
506		/* If it's still empty, it's just chaff. */
507		if (EMPTY(nsrr->addrs)) {
508			DPRINTF(("get_glue: removing empty '%s' NS",
509				 nsrr->name));
510			free_nsrr(nsrrsp, nsrr);
511		}
512	}
513	free(resp);
514	return (0);
515
516 cleanup:
517	free(resp);
518	return (-1);
519}
520
521static int
522save_ns(res_state statp, ns_msg *msg, ns_sect sect,
523	const char *owner, ns_class class, int opts,
524	rrset_ns *nsrrsp)
525{
526	int i;
527
528	for (i = 0; i < ns_msg_count(*msg, sect); i++) {
529		char tname[MAXDNAME];
530		const u_char *rdata;
531		rr_ns *nsrr;
532		ns_rr rr;
533
534		if (ns_parserr(msg, sect, i, &rr) < 0) {
535			DPRINTF(("save_ns: ns_parserr(%s, %d) failed",
536				 p_section(sect, ns_o_query), i));
537			return (-1);
538		}
539		if (ns_rr_type(rr) != ns_t_ns ||
540		    ns_rr_class(rr) != class ||
541		    ns_samename(ns_rr_name(rr), owner) != 1)
542			continue;
543		nsrr = find_ns(nsrrsp, ns_rr_name(rr));
544		if (nsrr == NULL) {
545			nsrr = malloc(sizeof *nsrr);
546			if (nsrr == NULL) {
547				DPRINTF(("save_ns: malloc failed"));
548				return (-1);
549			}
550			rdata = ns_rr_rdata(rr);
551			if (ns_name_uncompress(ns_msg_base(*msg),
552					       ns_msg_end(*msg), rdata,
553					       tname, sizeof tname) < 0) {
554				DPRINTF(("save_ns: ns_name_uncompress failed")
555					);
556				free(nsrr);
557				return (-1);
558			}
559			nsrr->name = strdup(tname);
560			if (nsrr->name == NULL) {
561				DPRINTF(("save_ns: strdup failed"));
562				free(nsrr);
563				return (-1);
564			}
565			INIT_LINK(nsrr, link);
566			INIT_LIST(nsrr->addrs);
567			nsrr->flags = 0;
568			APPEND(*nsrrsp, nsrr, link);
569		}
570		if (save_a(statp, msg, ns_s_ar,
571			   nsrr->name, class, opts, nsrr) < 0) {
572			DPRINTF(("save_ns: save_r('%s', %s) failed",
573				 nsrr->name, p_class(class)));
574			return (-1);
575		}
576	}
577	return (0);
578}
579
580static int
581save_a(res_state statp, ns_msg *msg, ns_sect sect,
582       const char *owner, ns_class class, int opts,
583       rr_ns *nsrr)
584{
585	int i;
586
587	for (i = 0; i < ns_msg_count(*msg, sect); i++) {
588		ns_rr rr;
589		rr_a *arr;
590
591		if (ns_parserr(msg, sect, i, &rr) < 0) {
592			DPRINTF(("save_a: ns_parserr(%s, %d) failed",
593				 p_section(sect, ns_o_query), i));
594			return (-1);
595		}
596		if ((ns_rr_type(rr) != ns_t_a &&
597		     ns_rr_type(rr) != ns_t_aaaa) ||
598		    ns_rr_class(rr) != class ||
599		    ns_samename(ns_rr_name(rr), owner) != 1 ||
600		    ns_rr_rdlen(rr) != NS_INADDRSZ)
601			continue;
602		if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa)
603			continue;
604		if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a)
605			continue;
606		arr = malloc(sizeof *arr);
607		if (arr == NULL) {
608			DPRINTF(("save_a: malloc failed"));
609			return (-1);
610		}
611		INIT_LINK(arr, link);
612		memset(&arr->addr, 0, sizeof(arr->addr));
613		switch (ns_rr_type(rr)) {
614		case ns_t_a:
615			arr->addr.sin.sin_family = AF_INET;
616#ifdef HAVE_SA_LEN
617			arr->addr.sin.sin_len = sizeof(arr->addr.sin);
618#endif
619			memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr),
620			       NS_INADDRSZ);
621			arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
622			nsrr->flags |= RR_NS_HAVE_V4;
623			break;
624		case ns_t_aaaa:
625			arr->addr.sin6.sin6_family = AF_INET6;
626#ifdef HAVE_SA_LEN
627			arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6);
628#endif
629			memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16);
630			arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
631			nsrr->flags |= RR_NS_HAVE_V6;
632			break;
633		default:
634			abort();
635		}
636		APPEND(nsrr->addrs, arr, link);
637	}
638	return (0);
639}
640
641static void
642free_nsrrset(rrset_ns *nsrrsp) {
643	rr_ns *nsrr;
644
645	while ((nsrr = HEAD(*nsrrsp)) != NULL)
646		free_nsrr(nsrrsp, nsrr);
647}
648
649static void
650free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) {
651	rr_a *arr;
652	char *tmp;
653
654	while ((arr = HEAD(nsrr->addrs)) != NULL) {
655		UNLINK(nsrr->addrs, arr, link);
656		free(arr);
657	}
658	DE_CONST(nsrr->name, tmp);
659	free(tmp);
660	UNLINK(*nsrrsp, nsrr, link);
661	free(nsrr);
662}
663
664static rr_ns *
665find_ns(rrset_ns *nsrrsp, const char *dname) {
666	rr_ns *nsrr;
667
668	for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link))
669		if (ns_samename(nsrr->name, dname) == 1)
670			return (nsrr);
671	return (NULL);
672}
673
674static int
675do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
676	 u_char *resp, ns_msg *msg)
677{
678	u_char req[NS_PACKETSZ];
679	int i, n;
680
681	n = res_nmkquery(statp, ns_o_query, dname, class, qtype,
682			 NULL, 0, NULL, req, NS_PACKETSZ);
683	if (n < 0) {
684		DPRINTF(("do_query: res_nmkquery failed"));
685		return (-1);
686	}
687	n = res_nsend(statp, req, n, resp, NS_MAXMSG);
688	if (n < 0) {
689		DPRINTF(("do_query: res_nsend failed"));
690		return (-1);
691	}
692	if (n == 0) {
693		DPRINTF(("do_query: res_nsend returned 0"));
694		errno = EMSGSIZE;
695		return (-1);
696	}
697	if (ns_initparse(resp, n, msg) < 0) {
698		DPRINTF(("do_query: ns_initparse failed"));
699		return (-1);
700	}
701	n = 0;
702	for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
703		ns_rr rr;
704
705		if (ns_parserr(msg, ns_s_an, i, &rr) < 0) {
706			DPRINTF(("do_query: ns_parserr failed"));
707			return (-1);
708		}
709		n += (ns_rr_class(rr) == class &&
710		      (ns_rr_type(rr) == ns_t_cname ||
711		       ns_rr_type(rr) == ns_t_dname));
712	}
713	return (n);
714}
715
716static void
717res_dprintf(const char *fmt, ...) {
718	va_list ap;
719
720	va_start(ap, fmt);
721	fputs(";; res_findzonecut: ", stderr);
722	vfprintf(stderr, fmt, ap);
723	fputc('\n', stderr);
724	va_end(ap);
725}
726
727/*! \file */
728