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