1 /* $NetBSD: res_findzonecut.c,v 1.1.1.2 2012/09/09 16:08:08 christos Exp $ */
2
3 #if !defined(lint) && !defined(SABER)
4 static const char rcsid[] = "Id: res_findzonecut.c,v 1.10 2005/10/11 00:10:16 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 /* 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 equivilent).
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 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)156 res_findzonecut(res_state statp, const char *dname, ns_class class, int opts,
157 char *zname, size_t zsize, struct in_addr *addrs, int naddrs)
158 {
159 int result, i;
160 union res_sockaddr_union *u;
161
162
163 opts |= RES_IPV4ONLY;
164 opts &= ~RES_IPV6ONLY;
165
166 u = calloc(naddrs, sizeof(*u));
167 if (u == NULL)
168 return(-1);
169
170 result = res_findzonecut2(statp, dname, class, opts, zname, zsize,
171 u, naddrs);
172
173 for (i = 0; i < result; i++) {
174 addrs[i] = u[i].sin.sin_addr;
175 }
176 free(u);
177 return (result);
178 }
179
180 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)181 res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts,
182 char *zname, size_t zsize, union res_sockaddr_union *addrs,
183 int naddrs)
184 {
185 char mname[NS_MAXDNAME];
186 u_long save_pfcode;
187 rrset_ns nsrrs;
188 int n;
189
190 DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d",
191 dname, p_class(class), (long)zsize, naddrs));
192 save_pfcode = statp->pfcode;
193 statp->pfcode |= RES_PRF_HEAD2 | RES_PRF_HEAD1 | RES_PRF_HEADX |
194 RES_PRF_QUES | RES_PRF_ANS |
195 RES_PRF_AUTH | RES_PRF_ADD;
196 INIT_LIST(nsrrs);
197
198 DPRINTF(("get the soa, and see if it has enough glue"));
199 if ((n = get_soa(statp, dname, class, opts, zname, zsize,
200 mname, sizeof mname, &nsrrs)) < 0 ||
201 ((opts & RES_EXHAUSTIVE) == 0 &&
202 (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
203 goto done;
204
205 DPRINTF(("get the ns rrset and see if it has enough glue"));
206 if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 ||
207 ((opts & RES_EXHAUSTIVE) == 0 &&
208 (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0))
209 goto done;
210
211 DPRINTF(("get the missing glue and see if it's finally enough"));
212 if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0)
213 n = satisfy(statp, mname, &nsrrs, addrs, naddrs);
214
215 done:
216 DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK"));
217 free_nsrrset(&nsrrs);
218 statp->pfcode = save_pfcode;
219 return (n);
220 }
221
222 /* Private. */
223
224 static int
satisfy(res_state statp,const char * mname,rrset_ns * nsrrsp,union res_sockaddr_union * addrs,int naddrs)225 satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp,
226 union res_sockaddr_union *addrs, int naddrs)
227 {
228 rr_ns *nsrr;
229 int n, x;
230
231 n = 0;
232 nsrr = find_ns(nsrrsp, mname);
233 if (nsrr != NULL) {
234 x = add_addrs(statp, nsrr, addrs, naddrs);
235 addrs += x;
236 naddrs -= x;
237 n += x;
238 }
239 for (nsrr = HEAD(*nsrrsp);
240 nsrr != NULL && naddrs > 0;
241 nsrr = NEXT(nsrr, link))
242 if (ns_samename(nsrr->name, mname) != 1) {
243 x = add_addrs(statp, nsrr, addrs, naddrs);
244 addrs += x;
245 naddrs -= x;
246 n += x;
247 }
248 DPRINTF(("satisfy(%s): %d", mname, n));
249 return (n);
250 }
251
252 static int
add_addrs(res_state statp,rr_ns * nsrr,union res_sockaddr_union * addrs,int naddrs)253 add_addrs(res_state statp, rr_ns *nsrr,
254 union res_sockaddr_union *addrs, int naddrs)
255 {
256 rr_a *arr;
257 int n = 0;
258
259 for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) {
260 if (naddrs <= 0)
261 return (0);
262 *addrs++ = arr->addr;
263 naddrs--;
264 n++;
265 }
266 DPRINTF(("add_addrs: %d", n));
267 return (n);
268 }
269
270 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)271 get_soa(res_state statp, const char *dname, ns_class class, int opts,
272 char *zname, size_t zsize, char *mname, size_t msize,
273 rrset_ns *nsrrsp)
274 {
275 char tname[NS_MAXDNAME];
276 u_char *resp = NULL;
277 int n, i, ancount, nscount;
278 ns_sect sect;
279 ns_msg msg;
280 u_int rcode;
281
282 /*
283 * Find closest enclosing SOA, even if it's for the root zone.
284 */
285
286 /* First canonicalize dname (exactly one unescaped trailing "."). */
287 if (ns_makecanon(dname, tname, sizeof tname) < 0)
288 goto cleanup;
289 dname = tname;
290
291 resp = malloc(NS_MAXMSG);
292 if (resp == NULL)
293 goto cleanup;
294
295 /* Now grovel the subdomains, hunting for an SOA answer or auth. */
296 for (;;) {
297 /* Leading or inter-label '.' are skipped here. */
298 while (*dname == '.')
299 dname++;
300
301 /* Is there an SOA? */
302 n = do_query(statp, dname, class, ns_t_soa, resp, &msg);
303 if (n < 0) {
304 DPRINTF(("get_soa: do_query('%s', %s) failed (%d)",
305 dname, p_class(class), n));
306 goto cleanup;
307 }
308 if (n > 0) {
309 DPRINTF(("get_soa: CNAME or DNAME found"));
310 sect = ns_s_max, n = 0;
311 } else {
312 rcode = ns_msg_getflag(msg, ns_f_rcode);
313 ancount = ns_msg_count(msg, ns_s_an);
314 nscount = ns_msg_count(msg, ns_s_ns);
315 if (ancount > 0 && rcode == ns_r_noerror)
316 sect = ns_s_an, n = ancount;
317 else if (nscount > 0)
318 sect = ns_s_ns, n = nscount;
319 else
320 sect = ns_s_max, n = 0;
321 }
322 for (i = 0; i < n; i++) {
323 const char *t;
324 const u_char *rdata;
325 ns_rr rr;
326
327 if (ns_parserr(&msg, sect, i, &rr) < 0) {
328 DPRINTF(("get_soa: ns_parserr(%s, %d) failed",
329 p_section(sect, ns_o_query), i));
330 goto cleanup;
331 }
332 if (ns_rr_type(rr) == ns_t_cname ||
333 ns_rr_type(rr) == ns_t_dname)
334 break;
335 if (ns_rr_type(rr) != ns_t_soa ||
336 ns_rr_class(rr) != class)
337 continue;
338 t = ns_rr_name(rr);
339 switch (sect) {
340 case ns_s_an:
341 if (ns_samedomain(dname, t) == 0) {
342 DPRINTF(
343 ("get_soa: ns_samedomain('%s', '%s') == 0",
344 dname, t)
345 );
346 errno = EPROTOTYPE;
347 goto cleanup;
348 }
349 break;
350 case ns_s_ns:
351 if (ns_samename(dname, t) == 1 ||
352 ns_samedomain(dname, t) == 0) {
353 DPRINTF(
354 ("get_soa: ns_samename() || !ns_samedomain('%s', '%s')",
355 dname, t)
356 );
357 errno = EPROTOTYPE;
358 goto cleanup;
359 }
360 break;
361 default:
362 abort();
363 }
364 if (strlen(t) + 1 > zsize) {
365 DPRINTF(("get_soa: zname(%lu) too small (%lu)",
366 (unsigned long)zsize,
367 (unsigned long)strlen(t) + 1));
368 errno = EMSGSIZE;
369 goto cleanup;
370 }
371 strcpy(zname, t);
372 rdata = ns_rr_rdata(rr);
373 if (ns_name_uncompress(resp, ns_msg_end(msg), rdata,
374 mname, msize) < 0) {
375 DPRINTF(("get_soa: ns_name_uncompress failed")
376 );
377 goto cleanup;
378 }
379 if (save_ns(statp, &msg, ns_s_ns,
380 zname, class, opts, nsrrsp) < 0) {
381 DPRINTF(("get_soa: save_ns failed"));
382 goto cleanup;
383 }
384 free(resp);
385 return (0);
386 }
387
388 /* If we're out of labels, then not even "." has an SOA! */
389 if (*dname == '\0')
390 break;
391
392 /* Find label-terminating "."; top of loop will skip it. */
393 while (*dname != '.') {
394 if (*dname == '\\')
395 if (*++dname == '\0') {
396 errno = EMSGSIZE;
397 goto cleanup;
398 }
399 dname++;
400 }
401 }
402 DPRINTF(("get_soa: out of labels"));
403 errno = EDESTADDRREQ;
404 cleanup:
405 if (resp != NULL)
406 free(resp);
407 return (-1);
408 }
409
410 static int
get_ns(res_state statp,const char * zname,ns_class class,int opts,rrset_ns * nsrrsp)411 get_ns(res_state statp, const char *zname, ns_class class, int opts,
412 rrset_ns *nsrrsp)
413 {
414 u_char *resp;
415 ns_msg msg;
416 int n;
417
418 resp = malloc(NS_MAXMSG);
419 if (resp == NULL)
420 return (-1);
421
422 /* Go and get the NS RRs for this zone. */
423 n = do_query(statp, zname, class, ns_t_ns, resp, &msg);
424 if (n != 0) {
425 DPRINTF(("get_ns: do_query('%s', %s) failed (%d)",
426 zname, p_class(class), n));
427 free(resp);
428 return (-1);
429 }
430
431 /* Remember the NS RRs and associated A RRs that came back. */
432 if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) {
433 DPRINTF(("get_ns save_ns('%s', %s) failed",
434 zname, p_class(class)));
435 free(resp);
436 return (-1);
437 }
438
439 free(resp);
440 return (0);
441 }
442
443 static int
get_glue(res_state statp,ns_class class,int opts,rrset_ns * nsrrsp)444 get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) {
445 rr_ns *nsrr, *nsrr_n;
446 u_char *resp;
447
448 resp = malloc(NS_MAXMSG);
449 if (resp == NULL)
450 return(-1);
451
452 /* Go and get the A RRs for each empty NS RR on our list. */
453 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) {
454 ns_msg msg;
455 int n;
456
457 nsrr_n = NEXT(nsrr, link);
458
459 if ((nsrr->flags & RR_NS_HAVE_V4) == 0) {
460 n = do_query(statp, nsrr->name, class, ns_t_a,
461 resp, &msg);
462 if (n < 0) {
463 DPRINTF(
464 ("get_glue: do_query('%s', %s') failed",
465 nsrr->name, p_class(class)));
466 goto cleanup;
467 }
468 if (n > 0) {
469 DPRINTF((
470 "get_glue: do_query('%s', %s') CNAME or DNAME found",
471 nsrr->name, p_class(class)));
472 }
473 if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
474 opts, nsrr) < 0) {
475 DPRINTF(("get_glue: save_r('%s', %s) failed",
476 nsrr->name, p_class(class)));
477 goto cleanup;
478 }
479 }
480
481 if ((nsrr->flags & RR_NS_HAVE_V6) == 0) {
482 n = do_query(statp, nsrr->name, class, ns_t_aaaa,
483 resp, &msg);
484 if (n < 0) {
485 DPRINTF(
486 ("get_glue: do_query('%s', %s') failed",
487 nsrr->name, p_class(class)));
488 goto cleanup;
489 }
490 if (n > 0) {
491 DPRINTF((
492 "get_glue: do_query('%s', %s') CNAME or DNAME found",
493 nsrr->name, p_class(class)));
494 }
495 if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
496 opts, nsrr) < 0) {
497 DPRINTF(("get_glue: save_r('%s', %s) failed",
498 nsrr->name, p_class(class)));
499 goto cleanup;
500 }
501 }
502
503 /* If it's still empty, it's just chaff. */
504 if (EMPTY(nsrr->addrs)) {
505 DPRINTF(("get_glue: removing empty '%s' NS",
506 nsrr->name));
507 free_nsrr(nsrrsp, nsrr);
508 }
509 }
510 free(resp);
511 return (0);
512
513 cleanup:
514 free(resp);
515 return (-1);
516 }
517
518 static int
save_ns(res_state statp,ns_msg * msg,ns_sect sect,const char * owner,ns_class class,int opts,rrset_ns * nsrrsp)519 save_ns(res_state statp, ns_msg *msg, ns_sect sect,
520 const char *owner, ns_class class, int opts,
521 rrset_ns *nsrrsp)
522 {
523 int i;
524
525 for (i = 0; i < ns_msg_count(*msg, sect); i++) {
526 char tname[MAXDNAME];
527 const u_char *rdata;
528 rr_ns *nsrr;
529 ns_rr rr;
530
531 if (ns_parserr(msg, sect, i, &rr) < 0) {
532 DPRINTF(("save_ns: ns_parserr(%s, %d) failed",
533 p_section(sect, ns_o_query), i));
534 return (-1);
535 }
536 if (ns_rr_type(rr) != ns_t_ns ||
537 ns_rr_class(rr) != class ||
538 ns_samename(ns_rr_name(rr), owner) != 1)
539 continue;
540 nsrr = find_ns(nsrrsp, ns_rr_name(rr));
541 if (nsrr == NULL) {
542 nsrr = malloc(sizeof *nsrr);
543 if (nsrr == NULL) {
544 DPRINTF(("save_ns: malloc failed"));
545 return (-1);
546 }
547 rdata = ns_rr_rdata(rr);
548 if (ns_name_uncompress(ns_msg_base(*msg),
549 ns_msg_end(*msg), rdata,
550 tname, sizeof tname) < 0) {
551 DPRINTF(("save_ns: ns_name_uncompress failed")
552 );
553 free(nsrr);
554 return (-1);
555 }
556 nsrr->name = strdup(tname);
557 if (nsrr->name == NULL) {
558 DPRINTF(("save_ns: strdup failed"));
559 free(nsrr);
560 return (-1);
561 }
562 INIT_LINK(nsrr, link);
563 INIT_LIST(nsrr->addrs);
564 nsrr->flags = 0;
565 APPEND(*nsrrsp, nsrr, link);
566 }
567 if (save_a(statp, msg, ns_s_ar,
568 nsrr->name, class, opts, nsrr) < 0) {
569 DPRINTF(("save_ns: save_r('%s', %s) failed",
570 nsrr->name, p_class(class)));
571 return (-1);
572 }
573 }
574 return (0);
575 }
576
577 static int
save_a(res_state statp,ns_msg * msg,ns_sect sect,const char * owner,ns_class class,int opts,rr_ns * nsrr)578 save_a(res_state statp, ns_msg *msg, ns_sect sect,
579 const char *owner, ns_class class, int opts,
580 rr_ns *nsrr)
581 {
582 int i;
583
584 for (i = 0; i < ns_msg_count(*msg, sect); i++) {
585 ns_rr rr;
586 rr_a *arr;
587
588 if (ns_parserr(msg, sect, i, &rr) < 0) {
589 DPRINTF(("save_a: ns_parserr(%s, %d) failed",
590 p_section(sect, ns_o_query), i));
591 return (-1);
592 }
593 if ((ns_rr_type(rr) != ns_t_a &&
594 ns_rr_type(rr) != ns_t_aaaa) ||
595 ns_rr_class(rr) != class ||
596 ns_samename(ns_rr_name(rr), owner) != 1 ||
597 ns_rr_rdlen(rr) != NS_INADDRSZ)
598 continue;
599 if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa)
600 continue;
601 if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a)
602 continue;
603 arr = malloc(sizeof *arr);
604 if (arr == NULL) {
605 DPRINTF(("save_a: malloc failed"));
606 return (-1);
607 }
608 INIT_LINK(arr, link);
609 memset(&arr->addr, 0, sizeof(arr->addr));
610 switch (ns_rr_type(rr)) {
611 case ns_t_a:
612 arr->addr.sin.sin_family = AF_INET;
613 #ifdef HAVE_SA_LEN
614 arr->addr.sin.sin_len = sizeof(arr->addr.sin);
615 #endif
616 memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr),
617 NS_INADDRSZ);
618 arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
619 nsrr->flags |= RR_NS_HAVE_V4;
620 break;
621 case ns_t_aaaa:
622 arr->addr.sin6.sin6_family = AF_INET6;
623 #ifdef HAVE_SA_LEN
624 arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6);
625 #endif
626 memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16);
627 arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
628 nsrr->flags |= RR_NS_HAVE_V6;
629 break;
630 default:
631 abort();
632 }
633 APPEND(nsrr->addrs, arr, link);
634 }
635 return (0);
636 }
637
638 static void
free_nsrrset(rrset_ns * nsrrsp)639 free_nsrrset(rrset_ns *nsrrsp) {
640 rr_ns *nsrr;
641
642 while ((nsrr = HEAD(*nsrrsp)) != NULL)
643 free_nsrr(nsrrsp, nsrr);
644 }
645
646 static void
free_nsrr(rrset_ns * nsrrsp,rr_ns * nsrr)647 free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) {
648 rr_a *arr;
649 char *tmp;
650
651 while ((arr = HEAD(nsrr->addrs)) != NULL) {
652 UNLINK(nsrr->addrs, arr, link);
653 free(arr);
654 }
655 DE_CONST(nsrr->name, tmp);
656 free(tmp);
657 UNLINK(*nsrrsp, nsrr, link);
658 free(nsrr);
659 }
660
661 static rr_ns *
find_ns(rrset_ns * nsrrsp,const char * dname)662 find_ns(rrset_ns *nsrrsp, const char *dname) {
663 rr_ns *nsrr;
664
665 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link))
666 if (ns_samename(nsrr->name, dname) == 1)
667 return (nsrr);
668 return (NULL);
669 }
670
671 static int
do_query(res_state statp,const char * dname,ns_class class,ns_type qtype,u_char * resp,ns_msg * msg)672 do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
673 u_char *resp, ns_msg *msg)
674 {
675 u_char req[NS_PACKETSZ];
676 int i, n;
677
678 n = res_nmkquery(statp, ns_o_query, dname, class, qtype,
679 NULL, 0, NULL, req, NS_PACKETSZ);
680 if (n < 0) {
681 DPRINTF(("do_query: res_nmkquery failed"));
682 return (-1);
683 }
684 n = res_nsend(statp, req, n, resp, NS_MAXMSG);
685 if (n < 0) {
686 DPRINTF(("do_query: res_nsend failed"));
687 return (-1);
688 }
689 if (n == 0) {
690 DPRINTF(("do_query: res_nsend returned 0"));
691 errno = EMSGSIZE;
692 return (-1);
693 }
694 if (ns_initparse(resp, n, msg) < 0) {
695 DPRINTF(("do_query: ns_initparse failed"));
696 return (-1);
697 }
698 n = 0;
699 for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
700 ns_rr rr;
701
702 if (ns_parserr(msg, ns_s_an, i, &rr) < 0) {
703 DPRINTF(("do_query: ns_parserr failed"));
704 return (-1);
705 }
706 n += (ns_rr_class(rr) == class &&
707 (ns_rr_type(rr) == ns_t_cname ||
708 ns_rr_type(rr) == ns_t_dname));
709 }
710 return (n);
711 }
712
713 static void
res_dprintf(const char * fmt,...)714 res_dprintf(const char *fmt, ...) {
715 va_list ap;
716
717 va_start(ap, fmt);
718 fputs(";; res_findzonecut: ", stderr);
719 vfprintf(stderr, fmt, ap);
720 fputc('\n', stderr);
721 va_end(ap);
722 }
723
724 /*! \file */
725