1 #if !defined(lint) && !defined(SABER)
2 static 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 * SPDX-License-Identifier: ISC
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 /* Import. */
25
26 #include "port_before.h"
27
28 #include <sys/param.h>
29 #include <sys/socket.h>
30 #include <sys/time.h>
31
32 #include <netinet/in.h>
33 #include <arpa/inet.h>
34 #include <arpa/nameser.h>
35
36 #include <errno.h>
37 #include <limits.h>
38 #include <netdb.h>
39 #include <stdarg.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43
44 #include <isc/list.h>
45
46 #include "port_after.h"
47
48 #include <resolv.h>
49
50 /* Data structures. */
51
52 typedef struct rr_a {
53 LINK(struct rr_a) link;
54 union res_sockaddr_union addr;
55 } rr_a;
56 typedef LIST(rr_a) rrset_a;
57
58 typedef struct rr_ns {
59 LINK(struct rr_ns) link;
60 const char * name;
61 unsigned int flags;
62 rrset_a addrs;
63 } rr_ns;
64 typedef LIST(rr_ns) rrset_ns;
65
66 #define RR_NS_HAVE_V4 0x01
67 #define RR_NS_HAVE_V6 0x02
68
69 /* Forward. */
70
71 static int satisfy(res_state, const char *, rrset_ns *,
72 union res_sockaddr_union *, int);
73 static int add_addrs(res_state, rr_ns *,
74 union res_sockaddr_union *, int);
75 static int get_soa(res_state, const char *, ns_class, int,
76 char *, size_t, char *, size_t,
77 rrset_ns *);
78 static int get_ns(res_state, const char *, ns_class, int, rrset_ns *);
79 static int get_glue(res_state, ns_class, int, rrset_ns *);
80 static int save_ns(res_state, ns_msg *, ns_sect,
81 const char *, ns_class, int, rrset_ns *);
82 static int save_a(res_state, ns_msg *, ns_sect,
83 const char *, ns_class, int, rr_ns *);
84 static void free_nsrrset(rrset_ns *);
85 static void free_nsrr(rrset_ns *, rr_ns *);
86 static rr_ns * find_ns(rrset_ns *, const char *);
87 static int do_query(res_state, const char *, ns_class, ns_type,
88 u_char *, ns_msg *);
89 static void res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2);
90
91 /* Macros. */
92
93 #define DPRINTF(x) do {\
94 int save_errno = errno; \
95 if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \
96 errno = save_errno; \
97 } while (0)
98
99 /* Public. */
100
101 /*%
102 * find enclosing zone for a <dname,class>, and some server addresses
103 *
104 * parameters:
105 *\li res - resolver context to work within (is modified)
106 *\li dname - domain name whose enclosing zone is desired
107 *\li class - class of dname (and its enclosing zone)
108 *\li zname - found zone name
109 *\li zsize - allocated size of zname
110 *\li addrs - found server addresses
111 *\li naddrs - max number of addrs
112 *
113 * return values:
114 *\li < 0 - an error occurred (check errno)
115 *\li = 0 - zname is now valid, but addrs[] wasn't changed
116 *\li > 0 - zname is now valid, and return value is number of addrs[] found
117 *
118 * notes:
119 *\li this function calls res_nsend() which means it depends on correctly
120 * functioning recursive nameservers (usually defined in /etc/resolv.conf
121 * or its local equivalent).
122 *
123 *\li we start by asking for an SOA<dname,class>. if we get one as an
124 * answer, that just means <dname,class> is a zone top, which is fine.
125 * more than likely we'll be told to go pound sand, in the form of a
126 * negative answer.
127 *
128 *\li note that we are not prepared to deal with referrals since that would
129 * only come from authority servers and our correctly functioning local
130 * recursive server would have followed the referral and got us something
131 * more definite.
132 *
133 *\li if the authority section contains an SOA, this SOA should also be the
134 * closest enclosing zone, since any intermediary zone cuts would've been
135 * returned as referrals and dealt with by our correctly functioning local
136 * recursive name server. but an SOA in the authority section should NOT
137 * match our dname (since that would have been returned in the answer
138 * section). an authority section SOA has to be "above" our dname.
139 *
140 *\li however, since authority section SOA's were once optional, it's
141 * possible that we'll have to go hunting for the enclosing SOA by
142 * ripping labels off the front of our dname -- this is known as "doing
143 * it the hard way."
144 *
145 *\li ultimately we want some server addresses, which are ideally the ones
146 * pertaining to the SOA.MNAME, but only if there is a matching NS RR.
147 * so the second phase (after we find an SOA) is to go looking for the
148 * NS RRset for that SOA's zone.
149 *
150 *\li no answer section processed by this code is allowed to contain CNAME
151 * or DNAME RR's. for the SOA query this means we strip a label and
152 * keep going. for the NS and A queries this means we just give up.
153 */
154
155 #ifndef _LIBC
156 int
res_findzonecut(res_state statp,const char * dname,ns_class class,int opts,char * zname,size_t zsize,struct in_addr * addrs,int naddrs)157 res_findzonecut(res_state statp, const char *dname, ns_class class, int opts,
158 char *zname, size_t zsize, struct in_addr *addrs, int naddrs)
159 {
160 int result, i;
161 union res_sockaddr_union *u;
162
163
164 opts |= RES_IPV4ONLY;
165 opts &= ~RES_IPV6ONLY;
166
167 u = calloc(naddrs, sizeof(*u));
168 if (u == NULL)
169 return(-1);
170
171 result = res_findzonecut2(statp, dname, class, opts, zname, zsize,
172 u, naddrs);
173
174 for (i = 0; i < result; i++) {
175 addrs[i] = u[i].sin.sin_addr;
176 }
177 free(u);
178 return (result);
179 }
180 #endif
181
182 int
res_findzonecut2(res_state statp,const char * dname,ns_class class,int opts,char * zname,size_t zsize,union res_sockaddr_union * addrs,int naddrs)183 res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts,
184 char *zname, size_t zsize, union res_sockaddr_union *addrs,
185 int naddrs)
186 {
187 char mname[NS_MAXDNAME];
188 u_long save_pfcode;
189 rrset_ns nsrrs;
190 int n;
191
192 DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d",
193 dname, p_class(class), (long)zsize, naddrs));
194 save_pfcode = statp->pfcode;
195 statp->pfcode |= RES_PRF_HEAD2 | RES_PRF_HEAD1 | RES_PRF_HEADX |
196 RES_PRF_QUES | RES_PRF_ANS |
197 RES_PRF_AUTH | RES_PRF_ADD;
198 INIT_LIST(nsrrs);
199
200 DPRINTF(("get the soa, and see if it has enough glue"));
201 if ((n = get_soa(statp, dname, class, opts, zname, zsize,
202 mname, sizeof mname, &nsrrs)) < 0 ||
203 ((opts & RES_EXHAUSTIVE) == 0 &&
204 (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
205 goto done;
206
207 DPRINTF(("get the ns rrset and see if it has enough glue"));
208 if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 ||
209 ((opts & RES_EXHAUSTIVE) == 0 &&
210 (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
211 goto done;
212
213 DPRINTF(("get the missing glue and see if it's finally enough"));
214 if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0)
215 n = satisfy(statp, mname, &nsrrs, addrs, naddrs);
216
217 done:
218 DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK"));
219 free_nsrrset(&nsrrs);
220 statp->pfcode = save_pfcode;
221 return (n);
222 }
223
224 /* Private. */
225
226 static int
satisfy(res_state statp,const char * mname,rrset_ns * nsrrsp,union res_sockaddr_union * addrs,int naddrs)227 satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp,
228 union res_sockaddr_union *addrs, int naddrs)
229 {
230 rr_ns *nsrr;
231 int n, x;
232
233 n = 0;
234 nsrr = find_ns(nsrrsp, mname);
235 if (nsrr != NULL) {
236 x = add_addrs(statp, nsrr, addrs, naddrs);
237 addrs += x;
238 naddrs -= x;
239 n += x;
240 }
241 for (nsrr = HEAD(*nsrrsp);
242 nsrr != NULL && naddrs > 0;
243 nsrr = NEXT(nsrr, link))
244 if (ns_samename(nsrr->name, mname) != 1) {
245 x = add_addrs(statp, nsrr, addrs, naddrs);
246 addrs += x;
247 naddrs -= x;
248 n += x;
249 }
250 DPRINTF(("satisfy(%s): %d", mname, n));
251 return (n);
252 }
253
254 static int
add_addrs(res_state statp,rr_ns * nsrr,union res_sockaddr_union * addrs,int naddrs)255 add_addrs(res_state statp, rr_ns *nsrr,
256 union res_sockaddr_union *addrs, int naddrs)
257 {
258 rr_a *arr;
259 int n = 0;
260
261 for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) {
262 if (naddrs <= 0)
263 return (0);
264 *addrs++ = arr->addr;
265 naddrs--;
266 n++;
267 }
268 DPRINTF(("add_addrs: %d", n));
269 return (n);
270 }
271
272 static int
get_soa(res_state statp,const char * dname,ns_class class,int opts,char * zname,size_t zsize,char * mname,size_t msize,rrset_ns * nsrrsp)273 get_soa(res_state statp, const char *dname, ns_class class, int opts,
274 char *zname, size_t zsize, char *mname, size_t msize,
275 rrset_ns *nsrrsp)
276 {
277 char tname[NS_MAXDNAME];
278 u_char *resp = NULL;
279 int n, i, ancount, nscount;
280 ns_sect sect;
281 ns_msg msg;
282 u_int rcode;
283
284 /*
285 * Find closest enclosing SOA, even if it's for the root zone.
286 */
287
288 /* First canonicalize dname (exactly one unescaped trailing "."). */
289 if (ns_makecanon(dname, tname, sizeof tname) < 0)
290 goto cleanup;
291 dname = tname;
292
293 resp = malloc(NS_MAXMSG);
294 if (resp == NULL)
295 goto cleanup;
296
297 /* Now grovel the subdomains, hunting for an SOA answer or auth. */
298 for (;;) {
299 /* Leading or inter-label '.' are skipped here. */
300 while (*dname == '.')
301 dname++;
302
303 /* Is there an SOA? */
304 n = do_query(statp, dname, class, ns_t_soa, resp, &msg);
305 if (n < 0) {
306 DPRINTF(("get_soa: do_query('%s', %s) failed (%d)",
307 dname, p_class(class), n));
308 goto cleanup;
309 }
310 if (n > 0) {
311 DPRINTF(("get_soa: CNAME or DNAME found"));
312 sect = ns_s_max, n = 0;
313 } else {
314 rcode = ns_msg_getflag(msg, ns_f_rcode);
315 ancount = ns_msg_count(msg, ns_s_an);
316 nscount = ns_msg_count(msg, ns_s_ns);
317 if (ancount > 0 && rcode == ns_r_noerror)
318 sect = ns_s_an, n = ancount;
319 else if (nscount > 0)
320 sect = ns_s_ns, n = nscount;
321 else
322 sect = ns_s_max, n = 0;
323 }
324 for (i = 0; i < n; i++) {
325 const char *t;
326 const u_char *rdata;
327 ns_rr rr;
328
329 if (ns_parserr(&msg, sect, i, &rr) < 0) {
330 DPRINTF(("get_soa: ns_parserr(%s, %d) failed",
331 p_section(sect, ns_o_query), i));
332 goto cleanup;
333 }
334 if (ns_rr_type(rr) == ns_t_cname ||
335 ns_rr_type(rr) == ns_t_dname)
336 break;
337 if (ns_rr_type(rr) != ns_t_soa ||
338 ns_rr_class(rr) != class)
339 continue;
340 t = ns_rr_name(rr);
341 switch (sect) {
342 case ns_s_an:
343 if (ns_samedomain(dname, t) == 0) {
344 DPRINTF(
345 ("get_soa: ns_samedomain('%s', '%s') == 0",
346 dname, t)
347 );
348 errno = EPROTOTYPE;
349 goto cleanup;
350 }
351 break;
352 case ns_s_ns:
353 if (ns_samename(dname, t) == 1 ||
354 ns_samedomain(dname, t) == 0) {
355 DPRINTF(
356 ("get_soa: ns_samename() || !ns_samedomain('%s', '%s')",
357 dname, t)
358 );
359 errno = EPROTOTYPE;
360 goto cleanup;
361 }
362 break;
363 default:
364 abort();
365 }
366 if (strlen(t) + 1 > zsize) {
367 DPRINTF(("get_soa: zname(%lu) too small (%lu)",
368 (unsigned long)zsize,
369 (unsigned long)strlen(t) + 1));
370 errno = EMSGSIZE;
371 goto cleanup;
372 }
373 strcpy(zname, t);
374 rdata = ns_rr_rdata(rr);
375 if (ns_name_uncompress(resp, ns_msg_end(msg), rdata,
376 mname, msize) < 0) {
377 DPRINTF(("get_soa: ns_name_uncompress failed")
378 );
379 goto cleanup;
380 }
381 if (save_ns(statp, &msg, ns_s_ns,
382 zname, class, opts, nsrrsp) < 0) {
383 DPRINTF(("get_soa: save_ns failed"));
384 goto cleanup;
385 }
386 free(resp);
387 return (0);
388 }
389
390 /* If we're out of labels, then not even "." has an SOA! */
391 if (*dname == '\0')
392 break;
393
394 /* Find label-terminating "."; top of loop will skip it. */
395 while (*dname != '.') {
396 if (*dname == '\\')
397 if (*++dname == '\0') {
398 errno = EMSGSIZE;
399 goto cleanup;
400 }
401 dname++;
402 }
403 }
404 DPRINTF(("get_soa: out of labels"));
405 errno = EDESTADDRREQ;
406 cleanup:
407 if (resp != NULL)
408 free(resp);
409 return (-1);
410 }
411
412 static int
get_ns(res_state statp,const char * zname,ns_class class,int opts,rrset_ns * nsrrsp)413 get_ns(res_state statp, const char *zname, ns_class class, int opts,
414 rrset_ns *nsrrsp)
415 {
416 u_char *resp;
417 ns_msg msg;
418 int n;
419
420 resp = malloc(NS_MAXMSG);
421 if (resp == NULL)
422 return (-1);
423
424 /* Go and get the NS RRs for this zone. */
425 n = do_query(statp, zname, class, ns_t_ns, resp, &msg);
426 if (n != 0) {
427 DPRINTF(("get_ns: do_query('%s', %s) failed (%d)",
428 zname, p_class(class), n));
429 free(resp);
430 return (-1);
431 }
432
433 /* Remember the NS RRs and associated A RRs that came back. */
434 if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) {
435 DPRINTF(("get_ns save_ns('%s', %s) failed",
436 zname, p_class(class)));
437 free(resp);
438 return (-1);
439 }
440
441 free(resp);
442 return (0);
443 }
444
445 static int
get_glue(res_state statp,ns_class class,int opts,rrset_ns * nsrrsp)446 get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) {
447 rr_ns *nsrr, *nsrr_n;
448 u_char *resp;
449
450 resp = malloc(NS_MAXMSG);
451 if (resp == NULL)
452 return(-1);
453
454 /* Go and get the A RRs for each empty NS RR on our list. */
455 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) {
456 ns_msg msg;
457 int n;
458
459 nsrr_n = NEXT(nsrr, link);
460
461 if ((nsrr->flags & RR_NS_HAVE_V4) == 0) {
462 n = do_query(statp, nsrr->name, class, ns_t_a,
463 resp, &msg);
464 if (n < 0) {
465 DPRINTF(
466 ("get_glue: do_query('%s', %s') failed",
467 nsrr->name, p_class(class)));
468 goto cleanup;
469 }
470 if (n > 0) {
471 DPRINTF((
472 "get_glue: do_query('%s', %s') CNAME or DNAME found",
473 nsrr->name, p_class(class)));
474 }
475 if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
476 opts, nsrr) < 0) {
477 DPRINTF(("get_glue: save_r('%s', %s) failed",
478 nsrr->name, p_class(class)));
479 goto cleanup;
480 }
481 }
482
483 if ((nsrr->flags & RR_NS_HAVE_V6) == 0) {
484 n = do_query(statp, nsrr->name, class, ns_t_aaaa,
485 resp, &msg);
486 if (n < 0) {
487 DPRINTF(
488 ("get_glue: do_query('%s', %s') failed",
489 nsrr->name, p_class(class)));
490 goto cleanup;
491 }
492 if (n > 0) {
493 DPRINTF((
494 "get_glue: do_query('%s', %s') CNAME or DNAME found",
495 nsrr->name, p_class(class)));
496 }
497 if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
498 opts, nsrr) < 0) {
499 DPRINTF(("get_glue: save_r('%s', %s) failed",
500 nsrr->name, p_class(class)));
501 goto cleanup;
502 }
503 }
504
505 /* If it's still empty, it's just chaff. */
506 if (EMPTY(nsrr->addrs)) {
507 DPRINTF(("get_glue: removing empty '%s' NS",
508 nsrr->name));
509 free_nsrr(nsrrsp, nsrr);
510 }
511 }
512 free(resp);
513 return (0);
514
515 cleanup:
516 free(resp);
517 return (-1);
518 }
519
520 static int
save_ns(res_state statp,ns_msg * msg,ns_sect sect,const char * owner,ns_class class,int opts,rrset_ns * nsrrsp)521 save_ns(res_state statp, ns_msg *msg, ns_sect sect,
522 const char *owner, ns_class class, int opts,
523 rrset_ns *nsrrsp)
524 {
525 int i;
526
527 for (i = 0; i < ns_msg_count(*msg, sect); i++) {
528 char tname[MAXDNAME];
529 const u_char *rdata;
530 rr_ns *nsrr;
531 ns_rr rr;
532
533 if (ns_parserr(msg, sect, i, &rr) < 0) {
534 DPRINTF(("save_ns: ns_parserr(%s, %d) failed",
535 p_section(sect, ns_o_query), i));
536 return (-1);
537 }
538 if (ns_rr_type(rr) != ns_t_ns ||
539 ns_rr_class(rr) != class ||
540 ns_samename(ns_rr_name(rr), owner) != 1)
541 continue;
542 nsrr = find_ns(nsrrsp, ns_rr_name(rr));
543 if (nsrr == NULL) {
544 nsrr = malloc(sizeof *nsrr);
545 if (nsrr == NULL) {
546 DPRINTF(("save_ns: malloc failed"));
547 return (-1);
548 }
549 rdata = ns_rr_rdata(rr);
550 if (ns_name_uncompress(ns_msg_base(*msg),
551 ns_msg_end(*msg), rdata,
552 tname, sizeof tname) < 0) {
553 DPRINTF(("save_ns: ns_name_uncompress failed")
554 );
555 free(nsrr);
556 return (-1);
557 }
558 nsrr->name = strdup(tname);
559 if (nsrr->name == NULL) {
560 DPRINTF(("save_ns: strdup failed"));
561 free(nsrr);
562 return (-1);
563 }
564 INIT_LINK(nsrr, link);
565 INIT_LIST(nsrr->addrs);
566 nsrr->flags = 0;
567 APPEND(*nsrrsp, nsrr, link);
568 }
569 if (save_a(statp, msg, ns_s_ar,
570 nsrr->name, class, opts, nsrr) < 0) {
571 DPRINTF(("save_ns: save_r('%s', %s) failed",
572 nsrr->name, p_class(class)));
573 return (-1);
574 }
575 }
576 return (0);
577 }
578
579 static int
save_a(res_state statp,ns_msg * msg,ns_sect sect,const char * owner,ns_class class,int opts,rr_ns * nsrr)580 save_a(res_state statp, ns_msg *msg, ns_sect sect,
581 const char *owner, ns_class class, int opts,
582 rr_ns *nsrr)
583 {
584 int i;
585
586 for (i = 0; i < ns_msg_count(*msg, sect); i++) {
587 ns_rr rr;
588 rr_a *arr;
589
590 if (ns_parserr(msg, sect, i, &rr) < 0) {
591 DPRINTF(("save_a: ns_parserr(%s, %d) failed",
592 p_section(sect, ns_o_query), i));
593 return (-1);
594 }
595 if ((ns_rr_type(rr) != ns_t_a &&
596 ns_rr_type(rr) != ns_t_aaaa) ||
597 ns_rr_class(rr) != class ||
598 ns_samename(ns_rr_name(rr), owner) != 1 ||
599 ns_rr_rdlen(rr) != NS_INADDRSZ)
600 continue;
601 if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa)
602 continue;
603 if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a)
604 continue;
605 arr = malloc(sizeof *arr);
606 if (arr == NULL) {
607 DPRINTF(("save_a: malloc failed"));
608 return (-1);
609 }
610 INIT_LINK(arr, link);
611 memset(&arr->addr, 0, sizeof(arr->addr));
612 switch (ns_rr_type(rr)) {
613 case ns_t_a:
614 arr->addr.sin.sin_family = AF_INET;
615 #ifdef HAVE_SA_LEN
616 arr->addr.sin.sin_len = sizeof(arr->addr.sin);
617 #endif
618 memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr),
619 NS_INADDRSZ);
620 arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
621 nsrr->flags |= RR_NS_HAVE_V4;
622 break;
623 case ns_t_aaaa:
624 arr->addr.sin6.sin6_family = AF_INET6;
625 #ifdef HAVE_SA_LEN
626 arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6);
627 #endif
628 memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16);
629 arr->addr.sin6.sin6_port = htons(NAMESERVER_PORT);
630 nsrr->flags |= RR_NS_HAVE_V6;
631 break;
632 default:
633 abort();
634 }
635 APPEND(nsrr->addrs, arr, link);
636 }
637 return (0);
638 }
639
640 static void
free_nsrrset(rrset_ns * nsrrsp)641 free_nsrrset(rrset_ns *nsrrsp) {
642 rr_ns *nsrr;
643
644 while ((nsrr = HEAD(*nsrrsp)) != NULL)
645 free_nsrr(nsrrsp, nsrr);
646 }
647
648 static void
free_nsrr(rrset_ns * nsrrsp,rr_ns * nsrr)649 free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) {
650 rr_a *arr;
651 char *tmp;
652
653 while ((arr = HEAD(nsrr->addrs)) != NULL) {
654 UNLINK(nsrr->addrs, arr, link);
655 free(arr);
656 }
657 DE_CONST(nsrr->name, tmp);
658 free(tmp);
659 UNLINK(*nsrrsp, nsrr, link);
660 free(nsrr);
661 }
662
663 static rr_ns *
find_ns(rrset_ns * nsrrsp,const char * dname)664 find_ns(rrset_ns *nsrrsp, const char *dname) {
665 rr_ns *nsrr;
666
667 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link))
668 if (ns_samename(nsrr->name, dname) == 1)
669 return (nsrr);
670 return (NULL);
671 }
672
673 static int
do_query(res_state statp,const char * dname,ns_class class,ns_type qtype,u_char * resp,ns_msg * msg)674 do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
675 u_char *resp, ns_msg *msg)
676 {
677 u_char req[NS_PACKETSZ];
678 int i, n;
679
680 n = res_nmkquery(statp, ns_o_query, dname, class, qtype,
681 NULL, 0, NULL, req, NS_PACKETSZ);
682 if (n < 0) {
683 DPRINTF(("do_query: res_nmkquery failed"));
684 return (-1);
685 }
686 n = res_nsend(statp, req, n, resp, NS_MAXMSG);
687 if (n < 0) {
688 DPRINTF(("do_query: res_nsend failed"));
689 return (-1);
690 }
691 if (n == 0) {
692 DPRINTF(("do_query: res_nsend returned 0"));
693 errno = EMSGSIZE;
694 return (-1);
695 }
696 if (ns_initparse(resp, n, msg) < 0) {
697 DPRINTF(("do_query: ns_initparse failed"));
698 return (-1);
699 }
700 n = 0;
701 for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
702 ns_rr rr;
703
704 if (ns_parserr(msg, ns_s_an, i, &rr) < 0) {
705 DPRINTF(("do_query: ns_parserr failed"));
706 return (-1);
707 }
708 n += (ns_rr_class(rr) == class &&
709 (ns_rr_type(rr) == ns_t_cname ||
710 ns_rr_type(rr) == ns_t_dname));
711 }
712 return (n);
713 }
714
715 static void
res_dprintf(const char * fmt,...)716 res_dprintf(const char *fmt, ...) {
717 va_list ap;
718
719 va_start(ap, fmt);
720 fputs(";; res_findzonecut: ", stderr);
721 vfprintf(stderr, fmt, ap);
722 fputc('\n', stderr);
723 va_end(ap);
724 }
725
726 /*! \file */
727