1 #if !defined(lint) && !defined(SABER)
2 static const char rcsid[] = "$Id: res_findzonecut.c,v 1.2.2.3.4.4 2005/10/11 00:48:16 marka Exp $";
6 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
7 * Copyright (c) 1999 by Internet Software Consortium.
9 * Permission to use, copy, modify, and distribute this software for any
10 * purpose with or without fee is hereby granted, provided that the above
11 * copyright notice and this permission notice appear in all copies.
13 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
14 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
15 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
16 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
17 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
18 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
19 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
22 #include <sys/cdefs.h>
23 __FBSDID("$FreeBSD$");
27 #include "port_before.h"
29 #include <sys/param.h>
30 #include <sys/socket.h>
33 #include <netinet/in.h>
34 #include <arpa/inet.h>
35 #include <arpa/nameser.h>
47 #include "port_after.h"
51 /* Data structures. */
54 LINK(struct rr_a) link;
55 union res_sockaddr_union addr;
57 typedef LIST(rr_a) rrset_a;
59 typedef struct rr_ns {
60 LINK(struct rr_ns) link;
65 typedef LIST(rr_ns) rrset_ns;
67 #define RR_NS_HAVE_V4 0x01
68 #define RR_NS_HAVE_V6 0x02
72 static int satisfy(res_state, const char *, rrset_ns *,
73 union res_sockaddr_union *, int);
74 static int add_addrs(res_state, rr_ns *,
75 union res_sockaddr_union *, int);
76 static int get_soa(res_state, const char *, ns_class, int,
77 char *, size_t, char *, size_t,
79 static int get_ns(res_state, const char *, ns_class, int, rrset_ns *);
80 static int get_glue(res_state, ns_class, int, rrset_ns *);
81 static int save_ns(res_state, ns_msg *, ns_sect,
82 const char *, ns_class, int, rrset_ns *);
83 static int save_a(res_state, ns_msg *, ns_sect,
84 const char *, ns_class, int, rr_ns *);
85 static void free_nsrrset(rrset_ns *);
86 static void free_nsrr(rrset_ns *, rr_ns *);
87 static rr_ns * find_ns(rrset_ns *, const char *);
88 static int do_query(res_state, const char *, ns_class, ns_type,
90 static void res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2);
94 #define DPRINTF(x) do {\
95 int save_errno = errno; \
96 if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \
104 * res_findzonecut(res, dname, class, zname, zsize, addrs, naddrs)
105 * find enclosing zone for a <dname,class>, and some server addresses
107 * res - resolver context to work within (is modified)
108 * dname - domain name whose enclosing zone is desired
109 * class - class of dname (and its enclosing zone)
110 * zname - found zone name
111 * zsize - allocated size of zname
112 * addrs - found server addresses
113 * naddrs - max number of addrs
115 * < 0 - an error occurred (check errno)
116 * = 0 - zname is now valid, but addrs[] wasn't changed
117 * > 0 - zname is now valid, and return value is number of addrs[] found
119 * 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).
123 * 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
128 * 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
133 * 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.
140 * 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
145 * 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.
150 * 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.
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)
161 union res_sockaddr_union *u;
164 opts |= RES_IPV4ONLY;
165 opts &= ~RES_IPV6ONLY;
167 u = calloc(naddrs, sizeof(*u));
171 result = res_findzonecut2(statp, dname, class, opts, zname, zsize,
174 for (i = 0; i < result; i++) {
175 addrs[i] = u[i].sin.sin_addr;
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,
187 char mname[NS_MAXDNAME];
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;
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))
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))
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);
218 DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK"));
219 free_nsrrset(&nsrrs);
220 statp->pfcode = save_pfcode;
227 satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp,
228 union res_sockaddr_union *addrs, int naddrs)
234 nsrr = find_ns(nsrrsp, mname);
236 x = add_addrs(statp, nsrr, addrs, naddrs);
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);
250 DPRINTF(("satisfy(%s): %d", mname, n));
255 add_addrs(res_state statp, rr_ns *nsrr,
256 union res_sockaddr_union *addrs, int naddrs)
261 for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) {
264 *addrs++ = arr->addr;
268 DPRINTF(("add_addrs: %d", n));
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,
277 char tname[NS_MAXDNAME];
279 int n, i, ancount, nscount;
285 * Find closest enclosing SOA, even if it's for the root zone.
288 /* First canonicalize dname (exactly one unescaped trailing "."). */
289 if (ns_makecanon(dname, tname, sizeof tname) < 0)
293 resp = malloc(NS_MAXMSG);
297 /* Now grovel the subdomains, hunting for an SOA answer or auth. */
299 /* Leading or inter-label '.' are skipped here. */
300 while (*dname == '.')
303 /* Is there an SOA? */
304 n = do_query(statp, dname, class, ns_t_soa, resp, &msg);
306 DPRINTF(("get_soa: do_query('%s', %s) failed (%d)",
307 dname, p_class(class), n));
311 DPRINTF(("get_soa: CNAME or DNAME found"));
312 sect = ns_s_max, n = 0;
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;
322 sect = ns_s_max, n = 0;
324 for (i = 0; i < n; i++) {
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));
334 if (ns_rr_type(rr) == ns_t_cname ||
335 ns_rr_type(rr) == ns_t_dname)
337 if (ns_rr_type(rr) != ns_t_soa ||
338 ns_rr_class(rr) != class)
343 if (ns_samedomain(dname, t) == 0) {
345 ("get_soa: ns_samedomain('%s', '%s') == 0",
353 if (ns_samename(dname, t) == 1 ||
354 ns_samedomain(dname, t) == 0) {
356 ("get_soa: ns_samename() || !ns_samedomain('%s', '%s')",
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));
374 rdata = ns_rr_rdata(rr);
375 if (ns_name_uncompress(resp, ns_msg_end(msg), rdata,
377 DPRINTF(("get_soa: ns_name_uncompress failed")
381 if (save_ns(statp, &msg, ns_s_ns,
382 zname, class, opts, nsrrsp) < 0) {
383 DPRINTF(("get_soa: save_ns failed"));
390 /* If we're out of labels, then not even "." has an SOA! */
394 /* Find label-terminating "."; top of loop will skip it. */
395 while (*dname != '.') {
397 if (*++dname == '\0') {
404 DPRINTF(("get_soa: out of labels"));
405 errno = EDESTADDRREQ;
413 get_ns(res_state statp, const char *zname, ns_class class, int opts,
420 resp = malloc(NS_MAXMSG);
424 /* Go and get the NS RRs for this zone. */
425 n = do_query(statp, zname, class, ns_t_ns, resp, &msg);
427 DPRINTF(("get_ns: do_query('%s', %s) failed (%d)",
428 zname, p_class(class), n));
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)));
446 get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) {
447 rr_ns *nsrr, *nsrr_n;
450 resp = malloc(NS_MAXMSG);
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) {
459 nsrr_n = NEXT(nsrr, link);
461 if ((nsrr->flags & RR_NS_HAVE_V4) == 0) {
462 n = do_query(statp, nsrr->name, class, ns_t_a,
466 ("get_glue: do_query('%s', %s') failed",
467 nsrr->name, p_class(class)));
472 "get_glue: do_query('%s', %s') CNAME or DNAME found",
473 nsrr->name, p_class(class)));
475 if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
477 DPRINTF(("get_glue: save_r('%s', %s) failed",
478 nsrr->name, p_class(class)));
483 if ((nsrr->flags & RR_NS_HAVE_V6) == 0) {
484 n = do_query(statp, nsrr->name, class, ns_t_aaaa,
488 ("get_glue: do_query('%s', %s') failed",
489 nsrr->name, p_class(class)));
494 "get_glue: do_query('%s', %s') CNAME or DNAME found",
495 nsrr->name, p_class(class)));
497 if (save_a(statp, &msg, ns_s_an, nsrr->name, class,
499 DPRINTF(("get_glue: save_r('%s', %s) failed",
500 nsrr->name, p_class(class)));
505 /* If it's still empty, it's just chaff. */
506 if (EMPTY(nsrr->addrs)) {
507 DPRINTF(("get_glue: removing empty '%s' NS",
509 free_nsrr(nsrrsp, nsrr);
521 save_ns(res_state statp, ns_msg *msg, ns_sect sect,
522 const char *owner, ns_class class, int opts,
527 for (i = 0; i < ns_msg_count(*msg, sect); i++) {
528 char tname[MAXDNAME];
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));
538 if (ns_rr_type(rr) != ns_t_ns ||
539 ns_rr_class(rr) != class ||
540 ns_samename(ns_rr_name(rr), owner) != 1)
542 nsrr = find_ns(nsrrsp, ns_rr_name(rr));
544 nsrr = malloc(sizeof *nsrr);
546 DPRINTF(("save_ns: malloc failed"));
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")
558 nsrr->name = strdup(tname);
559 if (nsrr->name == NULL) {
560 DPRINTF(("save_ns: strdup failed"));
564 INIT_LINK(nsrr, link);
565 INIT_LIST(nsrr->addrs);
567 APPEND(*nsrrsp, nsrr, link);
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)));
580 save_a(res_state statp, ns_msg *msg, ns_sect sect,
581 const char *owner, ns_class class, int opts,
586 for (i = 0; i < ns_msg_count(*msg, sect); i++) {
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));
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)
601 if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa)
603 if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a)
605 arr = malloc(sizeof *arr);
607 DPRINTF(("save_a: malloc failed"));
610 INIT_LINK(arr, link);
611 memset(&arr->addr, 0, sizeof(arr->addr));
612 switch (ns_rr_type(rr)) {
614 arr->addr.sin.sin_family = AF_INET;
616 arr->addr.sin.sin_len = sizeof(arr->addr.sin);
618 memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr),
620 arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
621 nsrr->flags |= RR_NS_HAVE_V4;
624 arr->addr.sin6.sin6_family = AF_INET6;
626 arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6);
628 memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16);
629 arr->addr.sin.sin_port = htons(NAMESERVER_PORT);
630 nsrr->flags |= RR_NS_HAVE_V6;
635 APPEND(nsrr->addrs, arr, link);
641 free_nsrrset(rrset_ns *nsrrsp) {
644 while ((nsrr = HEAD(*nsrrsp)) != NULL)
645 free_nsrr(nsrrsp, nsrr);
649 free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) {
653 while ((arr = HEAD(nsrr->addrs)) != NULL) {
654 UNLINK(nsrr->addrs, arr, link);
657 DE_CONST(nsrr->name, tmp);
659 UNLINK(*nsrrsp, nsrr, link);
664 find_ns(rrset_ns *nsrrsp, const char *dname) {
667 for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link))
668 if (ns_samename(nsrr->name, dname) == 1)
674 do_query(res_state statp, const char *dname, ns_class class, ns_type qtype,
675 u_char *resp, ns_msg *msg)
677 u_char req[NS_PACKETSZ];
680 n = res_nmkquery(statp, ns_o_query, dname, class, qtype,
681 NULL, 0, NULL, req, NS_PACKETSZ);
683 DPRINTF(("do_query: res_nmkquery failed"));
686 n = res_nsend(statp, req, n, resp, NS_MAXMSG);
688 DPRINTF(("do_query: res_nsend failed"));
692 DPRINTF(("do_query: res_nsend returned 0"));
696 if (ns_initparse(resp, n, msg) < 0) {
697 DPRINTF(("do_query: ns_initparse failed"));
701 for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) {
704 if (ns_parserr(msg, ns_s_an, i, &rr) < 0) {
705 DPRINTF(("do_query: ns_parserr failed"));
708 n += (ns_rr_class(rr) == class &&
709 (ns_rr_type(rr) == ns_t_cname ||
710 ns_rr_type(rr) == ns_t_dname));
716 res_dprintf(const char *fmt, ...) {
720 fputs(";; res_findzonecut: ", stderr);
721 vfprintf(stderr, fmt, ap);