1 /* $NetBSD: res_findzonecut.c,v 1.3 2022/04/19 20:32:17 rillig Exp $ */
2
3 /*
4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (c) 1999 by Internet Software Consortium.
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
17 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19 #include <sys/cdefs.h>
20 #if 0
21 static const char rcsid[] = "Id: res_findzonecut.c,v 1.10 2005/10/11 00:10:16 marka Exp ";
22 #else
23 __RCSID("$NetBSD: res_findzonecut.c,v 1.3 2022/04/19 20:32:17 rillig Exp $");
24 #endif
25
26
27 /* Import. */
28
29 #include "port_before.h"
30
31 #include <sys/param.h>
32 #include <sys/socket.h>
33 #include <sys/time.h>
34 #include <sys/queue.h>
35
36 #include <netinet/in.h>
37 #include <arpa/inet.h>
38 #include <arpa/nameser.h>
39
40 #include <errno.h>
41 #include <limits.h>
42 #include <netdb.h>
43 #include <stdarg.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47
48 #include "port_after.h"
49
50 #include <resolv.h>
51
52 /* Data structures. */
53
54 typedef struct rr_a {
55 TAILQ_ENTRY(rr_a) link;
56 union res_sockaddr_union addr;
57 } rr_a;
58 typedef TAILQ_HEAD(rrset_a, rr_a) rrset_a;
59
60 typedef struct rr_ns {
61 TAILQ_ENTRY(rr_ns) link;
62 const char * name;
63 unsigned int flags;
64 rrset_a addrs;
65 } rr_ns;
66 typedef TAILQ_HEAD(rrset_ns, rr_ns) rrset_ns;
67
68 #define RR_NS_HAVE_V4 0x01
69 #define RR_NS_HAVE_V6 0x02
70
71 /* Forward. */
72
73 static int satisfy(res_state, const char *, rrset_ns *,
74 union res_sockaddr_union *, int);
75 static int add_addrs(res_state, rr_ns *,
76 union res_sockaddr_union *, int);
77 static int get_soa(res_state, const char *, ns_class, int,
78 char *, size_t, char *, size_t,
79 rrset_ns *);
80 static int get_ns(res_state, const char *, ns_class, int, rrset_ns *);
81 static int get_glue(res_state, ns_class, int, rrset_ns *);
82 static int save_ns(res_state, ns_msg *, ns_sect,
83 const char *, ns_class, int, rrset_ns *);
84 static int save_a(res_state, ns_msg *, ns_sect,
85 const char *, ns_class, int, rr_ns *);
86 static void free_nsrrset(rrset_ns *);
87 static void free_nsrr(rrset_ns *, rr_ns *);
88 static rr_ns * find_ns(rrset_ns *, const char *);
89 static int do_query(res_state, const char *, ns_class, ns_type,
90 u_char *, ns_msg *);
91 static void res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2);
92
93 /* Macros. */
94
95 #define DPRINTF(x) do {\
96 int save_errno = errno; \
97 if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \
98 errno = save_errno; \
99 } while (0)
100
101 /* Public. */
102
103 /*%
104 * find enclosing zone for a <dname,class>, and some server addresses
105 *
106 * parameters:
107 *\li res - resolver context to work within (is modified)
108 *\li dname - domain name whose enclosing zone is desired
109 *\li class - class of dname (and its enclosing zone)
110 *\li zname - found zone name
111 *\li zsize - allocated size of zname
112 *\li addrs - found server addresses
113 *\li naddrs - max number of addrs
114 *
115 * return values:
116 *\li < 0 - an error occurred (check errno)
117 *\li = 0 - zname is now valid, but addrs[] wasn't changed
118 *\li > 0 - zname is now valid, and return value is number of addrs[] found
119 *
120 * notes:
121 *\li this function calls res_nsend() which means it depends on correctly
122 * functioning recursive nameservers (usually defined in /etc/resolv.conf
123 * or its local equivalent).
124 *
125 *\li we start by asking for an SOA<dname,class>. if we get one as an
126 * answer, that just means <dname,class> is a zone top, which is fine.
127 * more than likely we'll be told to go pound sand, in the form of a
128 * negative answer.
129 *
130 *\li note that we are not prepared to deal with referrals since that would
131 * only come from authority servers and our correctly functioning local
132 * recursive server would have followed the referral and got us something
133 * more definite.
134 *
135 *\li if the authority section contains an SOA, this SOA should also be the
136 * closest enclosing zone, since any intermediary zone cuts would've been
137 * returned as referrals and dealt with by our correctly functioning local
138 * recursive name server. but an SOA in the authority section should NOT
139 * match our dname (since that would have been returned in the answer
140 * section). an authority section SOA has to be "above" our dname.
141 *
142 *\li however, since authority section SOA's were once optional, it's
143 * possible that we'll have to go hunting for the enclosing SOA by
144 * ripping labels off the front of our dname -- this is known as "doing
145 * it the hard way."
146 *
147 *\li ultimately we want some server addresses, which are ideally the ones
148 * pertaining to the SOA.MNAME, but only if there is a matching NS RR.
149 * so the second phase (after we find an SOA) is to go looking for the
150 * NS RRset for that SOA's zone.
151 *
152 *\li no answer section processed by this code is allowed to contain CNAME
153 * or DNAME RR's. for the SOA query this means we strip a label and
154 * keep going. for the NS and A queries this means we just give up.
155 */
156
157 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)158 res_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
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 TAILQ_INIT(&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 TAILQ_FOREACH(nsrr, nsrrsp, link) {
242 if (naddrs <= 0)
243 break;
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 }
251 DPRINTF(("satisfy(%s): %d", mname, n));
252 return (n);
253 }
254
255 static int
add_addrs(res_state statp,rr_ns * nsrr,union res_sockaddr_union * addrs,int naddrs)256 add_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 TAILQ_FOREACH(arr, &nsrr->addrs, 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
273 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)274 get_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
413 static int
get_ns(res_state statp,const char * zname,ns_class class,int opts,rrset_ns * nsrrsp)414 get_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
446 static int
get_glue(res_state statp,ns_class class,int opts,rrset_ns * nsrrsp)447 get_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 TAILQ_FOREACH_SAFE(nsrr, nsrrsp, link, nsrr_n) {
457 ns_msg msg;
458 int n;
459
460 if ((nsrr->flags & RR_NS_HAVE_V4) == 0) {
461 n = do_query(statp, nsrr->name, class, ns_t_a,
462 resp, &msg);
463 if (n < 0) {
464 DPRINTF(
465 ("get_glue: do_query('%s', %s') failed",
466 nsrr->name, p_class(class)));
467 goto cleanup;
468 }
469 if (n > 0) {
470 DPRINTF((
471 "get_glue: do_query('%s', %s') CNAME or DNAME found",
472 nsrr->name, p_class(class)));
473 }
474 if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
475 opts, nsrr) < 0) {
476 DPRINTF(("get_glue: save_r('%s', %s) failed",
477 nsrr->name, p_class(class)));
478 goto cleanup;
479 }
480 }
481
482 if ((nsrr->flags & RR_NS_HAVE_V6) == 0) {
483 n = do_query(statp, nsrr->name, class, ns_t_aaaa,
484 resp, &msg);
485 if (n < 0) {
486 DPRINTF(
487 ("get_glue: do_query('%s', %s') failed",
488 nsrr->name, p_class(class)));
489 goto cleanup;
490 }
491 if (n > 0) {
492 DPRINTF((
493 "get_glue: do_query('%s', %s') CNAME or DNAME found",
494 nsrr->name, p_class(class)));
495 }
496 if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
497 opts, nsrr) < 0) {
498 DPRINTF(("get_glue: save_r('%s', %s) failed",
499 nsrr->name, p_class(class)));
500 goto cleanup;
501 }
502 }
503
504 /* If it's still empty, it's just chaff. */
505 if (TAILQ_EMPTY(&nsrr->addrs)) {
506 DPRINTF(("get_glue: removing empty '%s' NS",
507 nsrr->name));
508 free_nsrr(nsrrsp, nsrr);
509 }
510 }
511 free(resp);
512 return (0);
513
514 cleanup:
515 free(resp);
516 return (-1);
517 }
518
519 static int
save_ns(res_state statp,ns_msg * msg,ns_sect sect,const char * owner,ns_class class,int opts,rrset_ns * nsrrsp)520 save_ns(res_state statp, ns_msg *msg, ns_sect sect,
521 const char *owner, ns_class class, int opts,
522 rrset_ns *nsrrsp)
523 {
524 int i;
525
526 for (i = 0; i < ns_msg_count(*msg, sect); i++) {
527 char tname[MAXDNAME];
528 const u_char *rdata;
529 rr_ns *nsrr;
530 ns_rr rr;
531
532 if (ns_parserr(msg, sect, i, &rr) < 0) {
533 DPRINTF(("save_ns: ns_parserr(%s, %d) failed",
534 p_section(sect, ns_o_query), i));
535 return (-1);
536 }
537 if (ns_rr_type(rr) != ns_t_ns ||
538 ns_rr_class(rr) != class ||
539 ns_samename(ns_rr_name(rr), owner) != 1)
540 continue;
541 nsrr = find_ns(nsrrsp, ns_rr_name(rr));
542 if (nsrr == NULL) {
543 nsrr = malloc(sizeof *nsrr);
544 if (nsrr == NULL) {
545 DPRINTF(("save_ns: malloc failed"));
546 return (-1);
547 }
548 rdata = ns_rr_rdata(rr);
549 if (ns_name_uncompress(ns_msg_base(*msg),
550 ns_msg_end(*msg), rdata,
551 tname, sizeof tname) < 0) {
552 DPRINTF(("save_ns: ns_name_uncompress failed")
553 );
554 free(nsrr);
555 return (-1);
556 }
557 nsrr->name = strdup(tname);
558 if (nsrr->name == NULL) {
559 DPRINTF(("save_ns: strdup failed"));
560 free(nsrr);
561 return (-1);
562 }
563 TAILQ_INIT(&nsrr->addrs);
564 nsrr->flags = 0;
565 TAILQ_INSERT_TAIL(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 memset(&arr->addr, 0, sizeof(arr->addr));
609 switch (ns_rr_type(rr)) {
610 case ns_t_a:
611 arr->addr.sin.sin_family = AF_INET;
612 #ifdef HAVE_SA_LEN
613 arr->addr.sin.sin_len = sizeof(arr->addr.sin);
614 #endif
615 memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr),
616 NS_INADDRSZ);
617 arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
618 nsrr->flags |= RR_NS_HAVE_V4;
619 break;
620 case ns_t_aaaa:
621 arr->addr.sin6.sin6_family = AF_INET6;
622 #ifdef HAVE_SA_LEN
623 arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6);
624 #endif
625 memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16);
626 arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
627 nsrr->flags |= RR_NS_HAVE_V6;
628 break;
629 default:
630 abort();
631 }
632 TAILQ_INSERT_TAIL(&nsrr->addrs, arr, link);
633 }
634 return (0);
635 }
636
637 static void
free_nsrrset(rrset_ns * nsrrsp)638 free_nsrrset(rrset_ns *nsrrsp) {
639 rr_ns *nsrr, *tmp;
640
641 TAILQ_FOREACH_SAFE(nsrr, nsrrsp, link, tmp)
642 free_nsrr(nsrrsp, nsrr);
643 }
644
645 static void
free_nsrr(rrset_ns * nsrrsp,rr_ns * nsrr)646 free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) {
647 rr_a *arr, *n_arr;
648 char *tmp;
649
650 TAILQ_FOREACH_SAFE(arr, &nsrr->addrs, link, n_arr) {
651 TAILQ_REMOVE(&nsrr->addrs, arr, link);
652 free(arr);
653 }
654 DE_CONST(nsrr->name, tmp);
655 free(tmp);
656 TAILQ_REMOVE(nsrrsp, nsrr, link);
657 free(nsrr);
658 }
659
660 static rr_ns *
find_ns(rrset_ns * nsrrsp,const char * dname)661 find_ns(rrset_ns *nsrrsp, const char *dname) {
662 rr_ns *nsrr;
663
664 TAILQ_FOREACH(nsrr, nsrrsp, link)
665 if (ns_samename(nsrr->name, dname) == 1)
666 return (nsrr);
667 return (NULL);
668 }
669
670 static int
do_query(res_state statp,const char * dname,ns_class class,ns_type qtype,u_char * resp,ns_msg * msg)671 do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
672 u_char *resp, ns_msg *msg)
673 {
674 u_char req[NS_PACKETSZ];
675 int i, n;
676
677 n = res_nmkquery(statp, ns_o_query, dname, class, qtype,
678 NULL, 0, NULL, req, NS_PACKETSZ);
679 if (n < 0) {
680 DPRINTF(("do_query: res_nmkquery failed"));
681 return (-1);
682 }
683 n = res_nsend(statp, req, n, resp, NS_MAXMSG);
684 if (n < 0) {
685 DPRINTF(("do_query: res_nsend failed"));
686 return (-1);
687 }
688 if (n == 0) {
689 DPRINTF(("do_query: res_nsend returned 0"));
690 errno = EMSGSIZE;
691 return (-1);
692 }
693 if (ns_initparse(resp, n, msg) < 0) {
694 DPRINTF(("do_query: ns_initparse failed"));
695 return (-1);
696 }
697 n = 0;
698 for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
699 ns_rr rr;
700
701 if (ns_parserr(msg, ns_s_an, i, &rr) < 0) {
702 DPRINTF(("do_query: ns_parserr failed"));
703 return (-1);
704 }
705 n += (ns_rr_class(rr) == class &&
706 (ns_rr_type(rr) == ns_t_cname ||
707 ns_rr_type(rr) == ns_t_dname));
708 }
709 return (n);
710 }
711
712 static void
res_dprintf(const char * fmt,...)713 res_dprintf(const char *fmt, ...) {
714 va_list ap;
715
716 va_start(ap, fmt);
717 fputs(";; res_findzonecut: ", stderr);
718 vfprintf(stderr, fmt, ap);
719 fputc('\n', stderr);
720 va_end(ap);
721 }
722
723 /*! \file */
724