1 /* $KAME: getaddrinfo.c,v 1.15 2000/07/09 04:37:24 itojun Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the project nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 /*
35 * Issues to be discussed:
36 * - Return values. There are nonstandard return values defined and used
37 * in the source code. This is because RFC2553 is silent about which error
38 * code must be returned for which situation.
39 * - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is
40 * invalid. Current code accepts NULL to be compatible with other OSes.
41 *
42 * Note:
43 * - The code filters out AFs that are not supported by the kernel,
44 * when globbing NULL hostname (to loopback, or wildcard). Is it the right
45 * thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG
46 * in ai_flags?
47 * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.
48 * (1) what should we do against numeric hostname (2) what should we do
49 * against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready?
50 * non-loopback address configured? global address configured?
51 *
52 * OS specific notes for freebsd4:
53 * - FreeBSD supported $GAI. The code does not.
54 */
55
56 #include <sys/cdefs.h>
57 __FBSDID("$FreeBSD$");
58
59 #include "namespace.h"
60 #include <sys/param.h>
61 #include <sys/socket.h>
62 #include <net/if.h>
63 #include <netinet/in.h>
64 #include <net/if_types.h>
65 #include <ifaddrs.h>
66 #include <sys/queue.h>
67 #ifdef INET6
68 #include <sys/sysctl.h>
69 #include <sys/ioctl.h>
70 #include <netinet6/in6_var.h>
71 #include <netinet6/nd6.h>
72 #endif
73 #include <arpa/inet.h>
74 #include <arpa/nameser.h>
75 #include <rpc/rpc.h>
76 #include <rpcsvc/yp_prot.h>
77 #include <rpcsvc/ypclnt.h>
78 #include <netdb.h>
79 #include <resolv.h>
80 #include <string.h>
81 #include <stdlib.h>
82 #include <stddef.h>
83 #include <ctype.h>
84 #include <unistd.h>
85 #include <stdio.h>
86 #include <errno.h>
87
88 #include "res_config.h"
89
90 #ifdef DEBUG
91 #include <syslog.h>
92 #endif
93
94 #include <stdarg.h>
95 #include <nsswitch.h>
96 #include "un-namespace.h"
97 #include "netdb_private.h"
98 #include "libc_private.h"
99 #ifdef NS_CACHING
100 #include "nscache.h"
101 #endif
102
103 #define ANY 0
104 #define YES 1
105 #define NO 0
106
107 static const char in_addrany[] = { 0, 0, 0, 0 };
108 static const char in_loopback[] = { 127, 0, 0, 1 };
109 #ifdef INET6
110 static const char in6_addrany[] = {
111 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
112 };
113 static const char in6_loopback[] = {
114 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
115 };
116 #endif
117
118 struct policyqueue {
119 TAILQ_ENTRY(policyqueue) pc_entry;
120 #ifdef INET6
121 struct in6_addrpolicy pc_policy;
122 #endif
123 };
124 TAILQ_HEAD(policyhead, policyqueue);
125
126 static const struct afd {
127 int a_af;
128 int a_addrlen;
129 socklen_t a_socklen;
130 int a_off;
131 const char *a_addrany;
132 const char *a_loopback;
133 int a_scoped;
134 } afdl [] = {
135 #ifdef INET6
136 #define N_INET6 0
137 {PF_INET6, sizeof(struct in6_addr),
138 sizeof(struct sockaddr_in6),
139 offsetof(struct sockaddr_in6, sin6_addr),
140 in6_addrany, in6_loopback, 1},
141 #define N_INET 1
142 #define N_LOCAL 2
143 #else
144 #define N_INET 0
145 #define N_LOCAL 1
146 #endif
147 {PF_INET, sizeof(struct in_addr),
148 sizeof(struct sockaddr_in),
149 offsetof(struct sockaddr_in, sin_addr),
150 in_addrany, in_loopback, 0},
151 #define sizeofmember(type, member) (sizeof(((type *)0)->member))
152 {PF_LOCAL, sizeofmember(struct sockaddr_un, sun_path),
153 sizeof(struct sockaddr_un),
154 offsetof(struct sockaddr_un, sun_path),
155 NULL, NULL, 0},
156 {0, 0, 0, 0, NULL, NULL, 0},
157 };
158
159 struct explore {
160 int e_af;
161 int e_socktype;
162 int e_protocol;
163 int e_wild;
164 #define AF_ANY 0x01
165 #define SOCKTYPE_ANY 0x02
166 #define PROTOCOL_ANY 0x04
167 #define WILD_AF(ex) ((ex)->e_wild & AF_ANY)
168 #define WILD_SOCKTYPE(ex) ((ex)->e_wild & SOCKTYPE_ANY)
169 #define WILD_PROTOCOL(ex) ((ex)->e_wild & PROTOCOL_ANY)
170 };
171
172 static const struct explore explore[] = {
173 #ifdef INET6
174 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP,
175 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
176 { PF_INET6, SOCK_STREAM, IPPROTO_TCP,
177 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
178 { PF_INET6, SOCK_STREAM, IPPROTO_SCTP,
179 AF_ANY | SOCKTYPE_ANY },
180 { PF_INET6, SOCK_SEQPACKET, IPPROTO_SCTP,
181 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
182 { PF_INET6, SOCK_DGRAM, IPPROTO_UDPLITE,
183 AF_ANY | SOCKTYPE_ANY },
184 { PF_INET6, SOCK_RAW, ANY,
185 AF_ANY | PROTOCOL_ANY },
186 #endif
187 { PF_INET, SOCK_DGRAM, IPPROTO_UDP,
188 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
189 { PF_INET, SOCK_STREAM, IPPROTO_TCP,
190 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
191 { PF_INET, SOCK_STREAM, IPPROTO_SCTP,
192 AF_ANY | SOCKTYPE_ANY },
193 { PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP,
194 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
195 { PF_INET, SOCK_DGRAM, IPPROTO_UDPLITE,
196 AF_ANY | SOCKTYPE_ANY },
197 { PF_INET, SOCK_RAW, ANY,
198 AF_ANY | PROTOCOL_ANY },
199 { PF_LOCAL, SOCK_DGRAM, ANY,
200 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
201 { PF_LOCAL, SOCK_STREAM, ANY,
202 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
203 { PF_LOCAL, SOCK_SEQPACKET, ANY,
204 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
205 { -1, 0, 0, 0 },
206 };
207
208 #ifdef INET6
209 #define PTON_MAX 16
210 #else
211 #define PTON_MAX 4
212 #endif
213
214 #define AIO_SRCFLAG_DEPRECATED 0x1
215
216 struct ai_order {
217 union {
218 struct sockaddr_storage aiou_ss;
219 struct sockaddr aiou_sa;
220 } aio_src_un;
221 #define aio_srcsa aio_src_un.aiou_sa
222 u_int32_t aio_srcflag;
223 int aio_srcscope;
224 int aio_dstscope;
225 struct policyqueue *aio_srcpolicy;
226 struct policyqueue *aio_dstpolicy;
227 struct addrinfo *aio_ai;
228 int aio_matchlen;
229 int aio_initial_sequence;
230 };
231
232 static const ns_src default_dns_files[] = {
233 { NSSRC_FILES, NS_SUCCESS },
234 { NSSRC_DNS, NS_SUCCESS },
235 { 0 }
236 };
237
238 struct res_target {
239 struct res_target *next;
240 const char *name; /* domain name */
241 int qclass, qtype; /* class and type of query */
242 u_char *answer; /* buffer to put answer */
243 int anslen; /* size of answer buffer */
244 int n; /* result length */
245 };
246
247 #define MAXPACKET (64*1024)
248
249 typedef union {
250 HEADER hdr;
251 u_char buf[MAXPACKET];
252 } querybuf;
253
254 static int str2number(const char *, int *);
255 static int explore_copy(const struct addrinfo *, const struct addrinfo *,
256 struct addrinfo **);
257 static int explore_null(const struct addrinfo *,
258 const char *, struct addrinfo **);
259 static int explore_numeric(const struct addrinfo *, const char *,
260 const char *, struct addrinfo **, const char *);
261 static int explore_numeric_scope(const struct addrinfo *, const char *,
262 const char *, struct addrinfo **);
263 static int get_canonname(const struct addrinfo *,
264 struct addrinfo *, const char *);
265 static struct addrinfo *get_ai(const struct addrinfo *,
266 const struct afd *, const char *);
267 static struct addrinfo *copy_ai(const struct addrinfo *);
268 static int get_portmatch(const struct addrinfo *, const char *);
269 static int get_port(struct addrinfo *, const char *, int);
270 static const struct afd *find_afd(int);
271 static int addrconfig(struct addrinfo *);
272 #ifdef INET6
273 static int is_ifdisabled(char *);
274 #endif
275 static void set_source(struct ai_order *, struct policyhead *);
276 static int comp_dst(const void *, const void *);
277 #ifdef INET6
278 static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *);
279 #endif
280 static int gai_addr2scopetype(struct sockaddr *);
281
282 static int explore_fqdn(const struct addrinfo *, const char *,
283 const char *, struct addrinfo **);
284
285 static int reorder(struct addrinfo *);
286 static int get_addrselectpolicy(struct policyhead *);
287 static void free_addrselectpolicy(struct policyhead *);
288 static struct policyqueue *match_addrselectpolicy(struct sockaddr *,
289 struct policyhead *);
290 static int matchlen(struct sockaddr *, struct sockaddr *);
291
292 static struct addrinfo *getanswer(const querybuf *, int, const char *, int,
293 const struct addrinfo *, res_state);
294 #if defined(RESOLVSORT)
295 static int addr4sort(struct addrinfo *, res_state);
296 #endif
297 static int _dns_getaddrinfo(void *, void *, va_list);
298 static void _sethtent(FILE **);
299 static void _endhtent(FILE **);
300 static struct addrinfo *_gethtent(FILE **, const char *,
301 const struct addrinfo *);
302 static int _files_getaddrinfo(void *, void *, va_list);
303 #ifdef YP
304 static struct addrinfo *_yphostent(char *, const struct addrinfo *);
305 static int _yp_getaddrinfo(void *, void *, va_list);
306 #endif
307 #ifdef NS_CACHING
308 static int addrinfo_id_func(char *, size_t *, va_list, void *);
309 static int addrinfo_marshal_func(char *, size_t *, void *, va_list, void *);
310 static int addrinfo_unmarshal_func(char *, size_t, void *, va_list, void *);
311 #endif
312
313 static int res_queryN(const char *, struct res_target *, res_state);
314 static int res_searchN(const char *, struct res_target *, res_state);
315 static int res_querydomainN(const char *, const char *,
316 struct res_target *, res_state);
317
318 /* XXX macros that make external reference is BAD. */
319
320 #define GET_AI(ai, afd, addr) \
321 do { \
322 /* external reference: pai, error, and label free */ \
323 (ai) = get_ai(pai, (afd), (addr)); \
324 if ((ai) == NULL) { \
325 error = EAI_MEMORY; \
326 goto free; \
327 } \
328 } while (/*CONSTCOND*/0)
329
330 #define GET_PORT(ai, serv) \
331 do { \
332 /* external reference: error and label free */ \
333 error = get_port((ai), (serv), 0); \
334 if (error != 0) \
335 goto free; \
336 } while (/*CONSTCOND*/0)
337
338 #define GET_CANONNAME(ai, str) \
339 do { \
340 /* external reference: pai, error and label free */ \
341 error = get_canonname(pai, (ai), (str)); \
342 if (error != 0) \
343 goto free; \
344 } while (/*CONSTCOND*/0)
345
346 #define ERR(err) \
347 do { \
348 /* external reference: error, and label bad */ \
349 error = (err); \
350 goto bad; \
351 /*NOTREACHED*/ \
352 } while (/*CONSTCOND*/0)
353
354 #define MATCH_FAMILY(x, y, w) \
355 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC)))
356 #define MATCH(x, y, w) \
357 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
358
359 void
freeaddrinfo(struct addrinfo * ai)360 freeaddrinfo(struct addrinfo *ai)
361 {
362 struct addrinfo *next;
363
364 while (ai != NULL) {
365 next = ai->ai_next;
366 free(ai->ai_canonname);
367 /* no need to free(ai->ai_addr) */
368 free(ai);
369 ai = next;
370 }
371 }
372
373 static int
str2number(const char * p,int * portp)374 str2number(const char *p, int *portp)
375 {
376 char *ep;
377 unsigned long v;
378
379 if (*p == '\0')
380 return -1;
381 ep = NULL;
382 errno = 0;
383 v = strtoul(p, &ep, 10);
384 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX) {
385 *portp = v;
386 return 0;
387 } else
388 return -1;
389 }
390
391 int
getaddrinfo(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res)392 getaddrinfo(const char *hostname, const char *servname,
393 const struct addrinfo *hints, struct addrinfo **res)
394 {
395 struct addrinfo sentinel;
396 struct addrinfo *cur;
397 int error = 0;
398 struct addrinfo ai, ai0, *afai;
399 struct addrinfo *pai;
400 const struct afd *afd;
401 const struct explore *ex;
402 struct addrinfo *afailist[nitems(afdl)];
403 struct addrinfo *afai_unspec;
404 int found;
405 int numeric = 0;
406
407 /* ensure we return NULL on errors */
408 *res = NULL;
409
410 memset(&ai, 0, sizeof(ai));
411
412 memset(afailist, 0, sizeof(afailist));
413 afai_unspec = NULL;
414
415 memset(&sentinel, 0, sizeof(sentinel));
416 cur = &sentinel;
417 pai = &ai;
418 pai->ai_flags = 0;
419 pai->ai_family = PF_UNSPEC;
420 pai->ai_socktype = ANY;
421 pai->ai_protocol = ANY;
422 pai->ai_addrlen = 0;
423 pai->ai_canonname = NULL;
424 pai->ai_addr = NULL;
425 pai->ai_next = NULL;
426
427 if (hostname == NULL && servname == NULL)
428 return EAI_NONAME;
429 if (hints) {
430 /* error check for hints */
431 if (hints->ai_addrlen || hints->ai_canonname ||
432 hints->ai_addr || hints->ai_next)
433 ERR(EAI_BADHINTS); /* xxx */
434 if (hints->ai_flags & ~AI_MASK)
435 ERR(EAI_BADFLAGS);
436 switch (hints->ai_family) {
437 case PF_UNSPEC:
438 case PF_LOCAL:
439 case PF_INET:
440 #ifdef INET6
441 case PF_INET6:
442 #endif
443 break;
444 default:
445 ERR(EAI_FAMILY);
446 }
447 memcpy(pai, hints, sizeof(*pai));
448
449 /*
450 * if both socktype/protocol are specified, check if they
451 * are meaningful combination.
452 */
453 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
454 for (ex = explore; ex->e_af >= 0; ex++) {
455 if (!MATCH_FAMILY(pai->ai_family, ex->e_af,
456 WILD_AF(ex)))
457 continue;
458 if (!MATCH(pai->ai_socktype, ex->e_socktype,
459 WILD_SOCKTYPE(ex)))
460 continue;
461 if (!MATCH(pai->ai_protocol, ex->e_protocol,
462 WILD_PROTOCOL(ex)))
463 continue;
464
465 /* matched */
466 break;
467 }
468
469 if (ex->e_af < 0)
470 ERR(EAI_BADHINTS);
471 }
472 }
473
474 /*
475 * RFC 3493: AI_ALL and AI_V4MAPPED are effective only against
476 * AF_INET6 query. They need to be ignored if specified in other
477 * occasions.
478 */
479 switch (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) {
480 case AI_V4MAPPED:
481 case AI_ALL | AI_V4MAPPED:
482 #ifdef INET6
483 if (pai->ai_family != AF_INET6)
484 pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
485 break;
486 #endif
487 case AI_ALL:
488 pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
489 break;
490 }
491
492 /*
493 * check for special cases. (1) numeric servname is disallowed if
494 * socktype/protocol are left unspecified. (2) servname is disallowed
495 * for raw and other inet{,6} sockets.
496 */
497 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
498 #ifdef PF_INET6
499 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
500 #endif
501 ) {
502 ai0 = *pai; /* backup *pai */
503
504 if (pai->ai_family == PF_UNSPEC) {
505 #ifdef PF_INET6
506 pai->ai_family = PF_INET6;
507 #else
508 pai->ai_family = PF_INET;
509 #endif
510 }
511 error = get_portmatch(pai, servname);
512 if (error)
513 goto bad;
514
515 *pai = ai0;
516 }
517
518 ai0 = *pai;
519
520 /*
521 * NULL hostname, or numeric hostname.
522 * If numeric representation of AF1 can be interpreted as FQDN
523 * representation of AF2, we need to think again about the code below.
524 */
525 found = 0;
526 for (afd = afdl; afd->a_af; afd++) {
527 *pai = ai0;
528
529 if (!MATCH_FAMILY(pai->ai_family, afd->a_af, 1))
530 continue;
531
532 if (pai->ai_family == PF_UNSPEC)
533 pai->ai_family = afd->a_af;
534
535 if (hostname == NULL) {
536 error = explore_null(pai, servname,
537 &afailist[afd - afdl]);
538
539 /*
540 * Errors from explore_null should be unexpected and
541 * be caught to avoid returning an incomplete result.
542 */
543 if (error != 0)
544 goto bad;
545 } else {
546 error = explore_numeric_scope(pai, hostname, servname,
547 &afailist[afd - afdl]);
548
549 /*
550 * explore_numeric_scope returns an error for address
551 * families that do not match that of hostname.
552 * Thus we should not catch the error at this moment.
553 */
554 }
555
556 if (!error && afailist[afd - afdl])
557 found++;
558 }
559 if (found) {
560 numeric = 1;
561 goto globcopy;
562 }
563
564 if (hostname == NULL)
565 ERR(EAI_NONAME); /* used to be EAI_NODATA */
566 if (pai->ai_flags & AI_NUMERICHOST)
567 ERR(EAI_NONAME);
568
569 if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(&ai0))
570 ERR(EAI_FAIL);
571
572 /*
573 * hostname as alphabetical name.
574 */
575 *pai = ai0;
576 error = explore_fqdn(pai, hostname, servname, &afai_unspec);
577
578 globcopy:
579 for (ex = explore; ex->e_af >= 0; ex++) {
580 *pai = ai0;
581
582 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
583 continue;
584 if (!MATCH(pai->ai_socktype, ex->e_socktype,
585 WILD_SOCKTYPE(ex)))
586 continue;
587 if (!MATCH(pai->ai_protocol, ex->e_protocol,
588 WILD_PROTOCOL(ex)))
589 continue;
590
591 if (pai->ai_family == PF_UNSPEC)
592 pai->ai_family = ex->e_af;
593 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
594 pai->ai_socktype = ex->e_socktype;
595 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
596 pai->ai_protocol = ex->e_protocol;
597
598 /*
599 * if the servname does not match socktype/protocol, ignore it.
600 */
601 if (get_portmatch(pai, servname) != 0)
602 continue;
603
604 if (afai_unspec)
605 afai = afai_unspec;
606 else {
607 if ((afd = find_afd(pai->ai_family)) == NULL)
608 continue;
609 /* XXX assumes that afd points inside afdl[] */
610 afai = afailist[afd - afdl];
611 }
612 if (!afai)
613 continue;
614
615 error = explore_copy(pai, afai, &cur->ai_next);
616 if (error != 0)
617 goto bad;
618
619 while (cur && cur->ai_next)
620 cur = cur->ai_next;
621 }
622
623 /*
624 * ensure we return either:
625 * - error == 0, non-NULL *res
626 * - error != 0, NULL *res
627 */
628 if (error == 0) {
629 if (sentinel.ai_next) {
630 /*
631 * If the returned entry is for an active connection,
632 * and the given name is not numeric, reorder the
633 * list, so that the application would try the list
634 * in the most efficient order. Since the head entry
635 * of the original list may contain ai_canonname and
636 * that entry may be moved elsewhere in the new list,
637 * we keep the pointer and will restore it in the new
638 * head entry. (Note that RFC3493 requires the head
639 * entry store it when requested by the caller).
640 */
641 if (hints == NULL || !(hints->ai_flags & AI_PASSIVE)) {
642 if (!numeric) {
643 char *canonname;
644
645 canonname =
646 sentinel.ai_next->ai_canonname;
647 sentinel.ai_next->ai_canonname = NULL;
648 (void)reorder(&sentinel);
649 if (sentinel.ai_next->ai_canonname ==
650 NULL) {
651 sentinel.ai_next->ai_canonname
652 = canonname;
653 } else if (canonname != NULL)
654 free(canonname);
655 }
656 }
657 *res = sentinel.ai_next;
658 } else
659 error = EAI_FAIL;
660 }
661
662 bad:
663 if (afai_unspec)
664 freeaddrinfo(afai_unspec);
665 for (afd = afdl; afd->a_af; afd++) {
666 if (afailist[afd - afdl])
667 freeaddrinfo(afailist[afd - afdl]);
668 }
669 if (!*res)
670 if (sentinel.ai_next)
671 freeaddrinfo(sentinel.ai_next);
672
673 return (error);
674 }
675
676 static int
reorder(struct addrinfo * sentinel)677 reorder(struct addrinfo *sentinel)
678 {
679 struct addrinfo *ai, **aip;
680 struct ai_order *aio;
681 int i, n;
682 struct policyhead policyhead;
683
684 /* count the number of addrinfo elements for sorting. */
685 for (n = 0, ai = sentinel->ai_next; ai != NULL; ai = ai->ai_next, n++)
686 ;
687
688 /*
689 * If the number is small enough, we can skip the reordering process.
690 */
691 if (n <= 1)
692 return(n);
693
694 /* allocate a temporary array for sort and initialization of it. */
695 if ((aio = calloc(n, sizeof(*aio))) == NULL)
696 return(n); /* give up reordering */
697
698 /* retrieve address selection policy from the kernel */
699 TAILQ_INIT(&policyhead);
700 if (!get_addrselectpolicy(&policyhead)) {
701 /* no policy is installed into kernel, we don't sort. */
702 free(aio);
703 return (n);
704 }
705
706 for (i = 0, ai = sentinel->ai_next; i < n; ai = ai->ai_next, i++) {
707 aio[i].aio_ai = ai;
708 aio[i].aio_dstscope = gai_addr2scopetype(ai->ai_addr);
709 aio[i].aio_dstpolicy = match_addrselectpolicy(ai->ai_addr,
710 &policyhead);
711 set_source(&aio[i], &policyhead);
712 aio[i].aio_initial_sequence = i;
713 }
714
715 /* perform sorting. */
716 qsort(aio, n, sizeof(*aio), comp_dst);
717
718 /* reorder the addrinfo chain. */
719 for (i = 0, aip = &sentinel->ai_next; i < n; i++) {
720 *aip = aio[i].aio_ai;
721 aip = &aio[i].aio_ai->ai_next;
722 }
723 *aip = NULL;
724
725 /* cleanup and return */
726 free(aio);
727 free_addrselectpolicy(&policyhead);
728 return(n);
729 }
730
731 static int
get_addrselectpolicy(struct policyhead * head)732 get_addrselectpolicy(struct policyhead *head)
733 {
734 #ifdef INET6
735 int mib[] = { CTL_NET, PF_INET6, IPPROTO_IPV6, IPV6CTL_ADDRCTLPOLICY };
736 size_t l;
737 char *buf;
738 struct in6_addrpolicy *pol, *ep;
739
740 if (sysctl(mib, nitems(mib), NULL, &l, NULL, 0) < 0)
741 return (0);
742 if (l == 0)
743 return (0);
744 if ((buf = malloc(l)) == NULL)
745 return (0);
746 if (sysctl(mib, nitems(mib), buf, &l, NULL, 0) < 0) {
747 free(buf);
748 return (0);
749 }
750
751 ep = (struct in6_addrpolicy *)(buf + l);
752 for (pol = (struct in6_addrpolicy *)buf; pol + 1 <= ep; pol++) {
753 struct policyqueue *new;
754
755 if ((new = malloc(sizeof(*new))) == NULL) {
756 free_addrselectpolicy(head); /* make the list empty */
757 break;
758 }
759 new->pc_policy = *pol;
760 TAILQ_INSERT_TAIL(head, new, pc_entry);
761 }
762
763 free(buf);
764 return (1);
765 #else
766 return (0);
767 #endif
768 }
769
770 static void
free_addrselectpolicy(struct policyhead * head)771 free_addrselectpolicy(struct policyhead *head)
772 {
773 struct policyqueue *ent, *nent;
774
775 for (ent = TAILQ_FIRST(head); ent; ent = nent) {
776 nent = TAILQ_NEXT(ent, pc_entry);
777 TAILQ_REMOVE(head, ent, pc_entry);
778 free(ent);
779 }
780 }
781
782 static struct policyqueue *
match_addrselectpolicy(struct sockaddr * addr,struct policyhead * head)783 match_addrselectpolicy(struct sockaddr *addr, struct policyhead *head)
784 {
785 #ifdef INET6
786 struct policyqueue *ent, *bestent = NULL;
787 struct in6_addrpolicy *pol;
788 int matchlen, bestmatchlen = -1;
789 u_char *mp, *ep, *k, *p, m;
790 struct sockaddr_in6 key;
791
792 switch(addr->sa_family) {
793 case AF_INET6:
794 key = *(struct sockaddr_in6 *)addr;
795 break;
796 case AF_INET:
797 /* convert the address into IPv4-mapped IPv6 address. */
798 memset(&key, 0, sizeof(key));
799 key.sin6_family = AF_INET6;
800 key.sin6_len = sizeof(key);
801 _map_v4v6_address(
802 (char *)&((struct sockaddr_in *)addr)->sin_addr,
803 (char *)&key.sin6_addr);
804 break;
805 default:
806 return(NULL);
807 }
808
809 for (ent = TAILQ_FIRST(head); ent; ent = TAILQ_NEXT(ent, pc_entry)) {
810 pol = &ent->pc_policy;
811 matchlen = 0;
812
813 mp = (u_char *)&pol->addrmask.sin6_addr;
814 ep = mp + 16; /* XXX: scope field? */
815 k = (u_char *)&key.sin6_addr;
816 p = (u_char *)&pol->addr.sin6_addr;
817 for (; mp < ep && *mp; mp++, k++, p++) {
818 m = *mp;
819 if ((*k & m) != *p)
820 goto next; /* not match */
821 if (m == 0xff) /* short cut for a typical case */
822 matchlen += 8;
823 else {
824 while (m >= 0x80) {
825 matchlen++;
826 m <<= 1;
827 }
828 }
829 }
830
831 /* matched. check if this is better than the current best. */
832 if (matchlen > bestmatchlen) {
833 bestent = ent;
834 bestmatchlen = matchlen;
835 }
836
837 next:
838 continue;
839 }
840
841 return(bestent);
842 #else
843 return(NULL);
844 #endif
845
846 }
847
848 static void
set_source(struct ai_order * aio,struct policyhead * ph)849 set_source(struct ai_order *aio, struct policyhead *ph)
850 {
851 struct addrinfo ai = *aio->aio_ai;
852 struct sockaddr_storage ss;
853 socklen_t srclen;
854 int s;
855
856 /* set unspec ("no source is available"), just in case */
857 aio->aio_srcsa.sa_family = AF_UNSPEC;
858 aio->aio_srcscope = -1;
859
860 switch(ai.ai_family) {
861 case AF_INET:
862 #ifdef INET6
863 case AF_INET6:
864 #endif
865 break;
866 default: /* ignore unsupported AFs explicitly */
867 return;
868 }
869
870 /* XXX: make a dummy addrinfo to call connect() */
871 ai.ai_socktype = SOCK_DGRAM;
872 ai.ai_protocol = IPPROTO_UDP; /* is UDP too specific? */
873 ai.ai_next = NULL;
874 memset(&ss, 0, sizeof(ss));
875 memcpy(&ss, ai.ai_addr, ai.ai_addrlen);
876 ai.ai_addr = (struct sockaddr *)&ss;
877 get_port(&ai, "1", 0);
878
879 /* open a socket to get the source address for the given dst */
880 if ((s = _socket(ai.ai_family, ai.ai_socktype | SOCK_CLOEXEC,
881 ai.ai_protocol)) < 0)
882 return; /* give up */
883 #ifdef INET6
884 if (ai.ai_family == AF_INET6) {
885 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ai.ai_addr;
886 int off = 0;
887
888 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
889 (void)_setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
890 (char *)&off, sizeof(off));
891 }
892 #endif
893 if (_connect(s, ai.ai_addr, ai.ai_addrlen) < 0)
894 goto cleanup;
895 srclen = ai.ai_addrlen;
896 if (_getsockname(s, &aio->aio_srcsa, &srclen) < 0) {
897 aio->aio_srcsa.sa_family = AF_UNSPEC;
898 goto cleanup;
899 }
900 aio->aio_srcscope = gai_addr2scopetype(&aio->aio_srcsa);
901 aio->aio_srcpolicy = match_addrselectpolicy(&aio->aio_srcsa, ph);
902 aio->aio_matchlen = matchlen(&aio->aio_srcsa, aio->aio_ai->ai_addr);
903 #ifdef INET6
904 if (ai.ai_family == AF_INET6) {
905 struct in6_ifreq ifr6;
906 u_int32_t flags6;
907
908 memset(&ifr6, 0, sizeof(ifr6));
909 memcpy(&ifr6.ifr_addr, ai.ai_addr, ai.ai_addrlen);
910 if (_ioctl(s, SIOCGIFAFLAG_IN6, &ifr6) == 0) {
911 flags6 = ifr6.ifr_ifru.ifru_flags6;
912 if ((flags6 & IN6_IFF_DEPRECATED))
913 aio->aio_srcflag |= AIO_SRCFLAG_DEPRECATED;
914 }
915 }
916 #endif
917
918 cleanup:
919 _close(s);
920 return;
921 }
922
923 static int
matchlen(struct sockaddr * src,struct sockaddr * dst)924 matchlen(struct sockaddr *src, struct sockaddr *dst)
925 {
926 int match = 0;
927 u_char *s, *d;
928 u_char *lim, r;
929 int addrlen;
930
931 switch (src->sa_family) {
932 #ifdef INET6
933 case AF_INET6:
934 s = (u_char *)&((struct sockaddr_in6 *)src)->sin6_addr;
935 d = (u_char *)&((struct sockaddr_in6 *)dst)->sin6_addr;
936 addrlen = sizeof(struct in6_addr);
937 lim = s + addrlen;
938 break;
939 #endif
940 case AF_INET:
941 s = (u_char *)&((struct sockaddr_in *)src)->sin_addr;
942 d = (u_char *)&((struct sockaddr_in *)dst)->sin_addr;
943 addrlen = sizeof(struct in_addr);
944 lim = s + addrlen;
945 break;
946 default:
947 return(0);
948 }
949
950 while (s < lim)
951 if ((r = (*d++ ^ *s++)) != 0) {
952 while ((r & 0x80) == 0) {
953 match++;
954 r <<= 1;
955 }
956 break;
957 } else
958 match += 8;
959 return(match);
960 }
961
962 static int
comp_dst(const void * arg1,const void * arg2)963 comp_dst(const void *arg1, const void *arg2)
964 {
965 const struct ai_order *dst1 = arg1, *dst2 = arg2;
966
967 /*
968 * Rule 1: Avoid unusable destinations.
969 * XXX: we currently do not consider if an appropriate route exists.
970 */
971 if (dst1->aio_srcsa.sa_family != AF_UNSPEC &&
972 dst2->aio_srcsa.sa_family == AF_UNSPEC) {
973 return(-1);
974 }
975 if (dst1->aio_srcsa.sa_family == AF_UNSPEC &&
976 dst2->aio_srcsa.sa_family != AF_UNSPEC) {
977 return(1);
978 }
979
980 /* Rule 2: Prefer matching scope. */
981 if (dst1->aio_dstscope == dst1->aio_srcscope &&
982 dst2->aio_dstscope != dst2->aio_srcscope) {
983 return(-1);
984 }
985 if (dst1->aio_dstscope != dst1->aio_srcscope &&
986 dst2->aio_dstscope == dst2->aio_srcscope) {
987 return(1);
988 }
989
990 /* Rule 3: Avoid deprecated addresses. */
991 if (dst1->aio_srcsa.sa_family != AF_UNSPEC &&
992 dst2->aio_srcsa.sa_family != AF_UNSPEC) {
993 if (!(dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) &&
994 (dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) {
995 return(-1);
996 }
997 if ((dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) &&
998 !(dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) {
999 return(1);
1000 }
1001 }
1002
1003 /* Rule 4: Prefer home addresses. */
1004 /* XXX: not implemented yet */
1005
1006 /* Rule 5: Prefer matching label. */
1007 #ifdef INET6
1008 if (dst1->aio_srcpolicy && dst1->aio_dstpolicy &&
1009 dst1->aio_srcpolicy->pc_policy.label ==
1010 dst1->aio_dstpolicy->pc_policy.label &&
1011 (dst2->aio_srcpolicy == NULL || dst2->aio_dstpolicy == NULL ||
1012 dst2->aio_srcpolicy->pc_policy.label !=
1013 dst2->aio_dstpolicy->pc_policy.label)) {
1014 return(-1);
1015 }
1016 if (dst2->aio_srcpolicy && dst2->aio_dstpolicy &&
1017 dst2->aio_srcpolicy->pc_policy.label ==
1018 dst2->aio_dstpolicy->pc_policy.label &&
1019 (dst1->aio_srcpolicy == NULL || dst1->aio_dstpolicy == NULL ||
1020 dst1->aio_srcpolicy->pc_policy.label !=
1021 dst1->aio_dstpolicy->pc_policy.label)) {
1022 return(1);
1023 }
1024 #endif
1025
1026 /* Rule 6: Prefer higher precedence. */
1027 #ifdef INET6
1028 if (dst1->aio_dstpolicy &&
1029 (dst2->aio_dstpolicy == NULL ||
1030 dst1->aio_dstpolicy->pc_policy.preced >
1031 dst2->aio_dstpolicy->pc_policy.preced)) {
1032 return(-1);
1033 }
1034 if (dst2->aio_dstpolicy &&
1035 (dst1->aio_dstpolicy == NULL ||
1036 dst2->aio_dstpolicy->pc_policy.preced >
1037 dst1->aio_dstpolicy->pc_policy.preced)) {
1038 return(1);
1039 }
1040 #endif
1041
1042 /* Rule 7: Prefer native transport. */
1043 /* XXX: not implemented yet */
1044
1045 /* Rule 8: Prefer smaller scope. */
1046 if (dst1->aio_dstscope >= 0 &&
1047 dst1->aio_dstscope < dst2->aio_dstscope) {
1048 return(-1);
1049 }
1050 if (dst2->aio_dstscope >= 0 &&
1051 dst2->aio_dstscope < dst1->aio_dstscope) {
1052 return(1);
1053 }
1054
1055 /*
1056 * Rule 9: Use longest matching prefix.
1057 * We compare the match length in a same AF only.
1058 */
1059 if (dst1->aio_ai->ai_addr->sa_family ==
1060 dst2->aio_ai->ai_addr->sa_family &&
1061 dst1->aio_ai->ai_addr->sa_family != AF_INET) {
1062 if (dst1->aio_matchlen > dst2->aio_matchlen) {
1063 return(-1);
1064 }
1065 if (dst1->aio_matchlen < dst2->aio_matchlen) {
1066 return(1);
1067 }
1068 }
1069
1070 /* Rule 10: Otherwise, leave the order unchanged. */
1071
1072 /*
1073 * Note that qsort is unstable; so, we can't return zero and
1074 * expect the order to be unchanged.
1075 * That also means we can't depend on the current position of
1076 * dst2 being after dst1. We must enforce the initial order
1077 * with an explicit compare on the original position.
1078 * The qsort specification requires that "When the same objects
1079 * (consisting of width bytes, irrespective of their current
1080 * positions in the array) are passed more than once to the
1081 * comparison function, the results shall be consistent with one
1082 * another."
1083 * In other words, If A < B, then we must also return B > A.
1084 */
1085 if (dst2->aio_initial_sequence < dst1->aio_initial_sequence)
1086 return(1);
1087
1088 return(-1);
1089 }
1090
1091 /*
1092 * Copy from scope.c.
1093 * XXX: we should standardize the functions and link them as standard
1094 * library.
1095 */
1096 static int
gai_addr2scopetype(struct sockaddr * sa)1097 gai_addr2scopetype(struct sockaddr *sa)
1098 {
1099 #ifdef INET6
1100 struct sockaddr_in6 *sa6;
1101 #endif
1102 struct sockaddr_in *sa4;
1103
1104 switch(sa->sa_family) {
1105 #ifdef INET6
1106 case AF_INET6:
1107 sa6 = (struct sockaddr_in6 *)sa;
1108 if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
1109 /* just use the scope field of the multicast address */
1110 return(sa6->sin6_addr.s6_addr[2] & 0x0f);
1111 }
1112 /*
1113 * Unicast addresses: map scope type to corresponding scope
1114 * value defined for multcast addresses.
1115 * XXX: hardcoded scope type values are bad...
1116 */
1117 if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr))
1118 return(1); /* node local scope */
1119 if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr))
1120 return(2); /* link-local scope */
1121 if (IN6_IS_ADDR_SITELOCAL(&sa6->sin6_addr))
1122 return(5); /* site-local scope */
1123 return(14); /* global scope */
1124 break;
1125 #endif
1126 case AF_INET:
1127 /*
1128 * IPv4 pseudo scoping according to RFC 3484.
1129 */
1130 sa4 = (struct sockaddr_in *)sa;
1131 /* IPv4 autoconfiguration addresses have link-local scope. */
1132 if (((u_char *)&sa4->sin_addr)[0] == 169 &&
1133 ((u_char *)&sa4->sin_addr)[1] == 254)
1134 return(2);
1135 /* Private addresses have site-local scope. */
1136 if (((u_char *)&sa4->sin_addr)[0] == 10 ||
1137 (((u_char *)&sa4->sin_addr)[0] == 172 &&
1138 (((u_char *)&sa4->sin_addr)[1] & 0xf0) == 16) ||
1139 (((u_char *)&sa4->sin_addr)[0] == 192 &&
1140 ((u_char *)&sa4->sin_addr)[1] == 168))
1141 return(14); /* XXX: It should be 5 unless NAT */
1142 /* Loopback addresses have link-local scope. */
1143 if (((u_char *)&sa4->sin_addr)[0] == 127)
1144 return(2);
1145 return(14);
1146 break;
1147 default:
1148 errno = EAFNOSUPPORT; /* is this a good error? */
1149 return(-1);
1150 }
1151 }
1152
1153 static int
explore_copy(const struct addrinfo * pai,const struct addrinfo * src0,struct addrinfo ** res)1154 explore_copy(const struct addrinfo *pai, const struct addrinfo *src0,
1155 struct addrinfo **res)
1156 {
1157 int error;
1158 struct addrinfo sentinel, *cur;
1159 const struct addrinfo *src;
1160
1161 error = 0;
1162 sentinel.ai_next = NULL;
1163 cur = &sentinel;
1164
1165 for (src = src0; src != NULL; src = src->ai_next) {
1166 if (src->ai_family != pai->ai_family)
1167 continue;
1168
1169 cur->ai_next = copy_ai(src);
1170 if (!cur->ai_next) {
1171 error = EAI_MEMORY;
1172 goto fail;
1173 }
1174
1175 cur->ai_next->ai_socktype = pai->ai_socktype;
1176 cur->ai_next->ai_protocol = pai->ai_protocol;
1177 cur = cur->ai_next;
1178 }
1179
1180 *res = sentinel.ai_next;
1181 return 0;
1182
1183 fail:
1184 freeaddrinfo(sentinel.ai_next);
1185 return error;
1186 }
1187
1188 /*
1189 * hostname == NULL.
1190 * passive socket -> anyaddr (0.0.0.0 or ::)
1191 * non-passive socket -> localhost (127.0.0.1 or ::1)
1192 */
1193 static int
explore_null(const struct addrinfo * pai,const char * servname,struct addrinfo ** res)1194 explore_null(const struct addrinfo *pai, const char *servname,
1195 struct addrinfo **res)
1196 {
1197 int s;
1198 const struct afd *afd;
1199 struct addrinfo *ai;
1200 int error;
1201
1202 *res = NULL;
1203 ai = NULL;
1204
1205 if (pai->ai_family == PF_LOCAL)
1206 return (0);
1207
1208 /*
1209 * filter out AFs that are not supported by the kernel
1210 * XXX errno?
1211 */
1212 s = _socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
1213 if (s < 0) {
1214 if (errno != EMFILE)
1215 return 0;
1216 } else
1217 _close(s);
1218
1219 afd = find_afd(pai->ai_family);
1220 if (afd == NULL)
1221 return 0;
1222
1223 if (pai->ai_flags & AI_PASSIVE) {
1224 GET_AI(ai, afd, afd->a_addrany);
1225 GET_PORT(ai, servname);
1226 } else {
1227 GET_AI(ai, afd, afd->a_loopback);
1228 GET_PORT(ai, servname);
1229 }
1230
1231 *res = ai;
1232 return 0;
1233
1234 free:
1235 if (ai != NULL)
1236 freeaddrinfo(ai);
1237 return error;
1238 }
1239
1240 /*
1241 * numeric hostname
1242 */
1243 static int
explore_numeric(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,const char * canonname)1244 explore_numeric(const struct addrinfo *pai, const char *hostname,
1245 const char *servname, struct addrinfo **res, const char *canonname)
1246 {
1247 const struct afd *afd;
1248 struct addrinfo *ai, ai0;
1249 int error;
1250 char pton[PTON_MAX], path[PATH_MAX], *p;
1251
1252 #ifdef CTASSERT
1253 CTASSERT(sizeofmember(struct sockaddr_un, sun_path) <= PATH_MAX);
1254 #endif
1255 *res = NULL;
1256 ai = NULL;
1257
1258 afd = find_afd(pai->ai_family);
1259 if (afd == NULL)
1260 return 0;
1261
1262 switch (afd->a_af) {
1263 case AF_LOCAL:
1264 if (hostname[0] != '/')
1265 ERR(EAI_NONAME);
1266 if (strlen(hostname) > afd->a_addrlen)
1267 ERR(EAI_MEMORY);
1268 /* NUL-termination does not need to be guaranteed. */
1269 strncpy(path, hostname, afd->a_addrlen);
1270 p = &path[0];
1271 break;
1272 case AF_INET:
1273 /*
1274 * RFC3493 requires getaddrinfo() to accept AF_INET formats
1275 * that are accepted by inet_addr() and its family. The
1276 * accepted forms includes the "classful" one, which inet_pton
1277 * does not accept. So we need to separate the case for
1278 * AF_INET.
1279 */
1280 if (inet_aton(hostname, (struct in_addr *)pton) != 1 ||
1281 hostname[strspn(hostname, "0123456789.xabcdefXABCDEF")] != '\0')
1282 return 0;
1283 p = pton;
1284 break;
1285 default:
1286 if (inet_pton(afd->a_af, hostname, pton) != 1) {
1287 if (pai->ai_family != AF_INET6 ||
1288 (pai->ai_flags & AI_V4MAPPED) != AI_V4MAPPED)
1289 return 0;
1290 if (inet_aton(hostname, (struct in_addr *)pton) != 1)
1291 return 0;
1292 afd = &afdl[N_INET];
1293 ai0 = *pai;
1294 ai0.ai_family = AF_INET;
1295 pai = &ai0;
1296 }
1297 p = pton;
1298 break;
1299 }
1300
1301 if (pai->ai_family == afd->a_af) {
1302 GET_AI(ai, afd, p);
1303 GET_PORT(ai, servname);
1304 if ((pai->ai_family == AF_INET ||
1305 pai->ai_family == AF_INET6) &&
1306 (pai->ai_flags & AI_CANONNAME)) {
1307 /*
1308 * Set the numeric address itself as the canonical
1309 * name, based on a clarification in RFC3493.
1310 */
1311 GET_CANONNAME(ai, canonname);
1312 }
1313 } else {
1314 /*
1315 * XXX: This should not happen since we already matched the AF
1316 * by find_afd.
1317 */
1318 ERR(EAI_FAMILY);
1319 }
1320
1321 *res = ai;
1322 return 0;
1323
1324 free:
1325 bad:
1326 if (ai != NULL)
1327 freeaddrinfo(ai);
1328 return error;
1329 }
1330
1331 /*
1332 * numeric hostname with scope
1333 */
1334 static int
explore_numeric_scope(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res)1335 explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
1336 const char *servname, struct addrinfo **res)
1337 {
1338 #if !defined(SCOPE_DELIMITER) || !defined(INET6)
1339 return explore_numeric(pai, hostname, servname, res, hostname);
1340 #else
1341 const struct afd *afd;
1342 struct addrinfo *cur;
1343 int error;
1344 char *cp, *hostname2 = NULL, *scope, *addr;
1345 struct sockaddr_in6 *sin6;
1346
1347 afd = find_afd(pai->ai_family);
1348 if (afd == NULL)
1349 return 0;
1350
1351 if (!afd->a_scoped)
1352 return explore_numeric(pai, hostname, servname, res, hostname);
1353
1354 cp = strchr(hostname, SCOPE_DELIMITER);
1355 if (cp == NULL)
1356 return explore_numeric(pai, hostname, servname, res, hostname);
1357
1358 /*
1359 * Handle special case of <scoped_address><delimiter><scope id>
1360 */
1361 hostname2 = strdup(hostname);
1362 if (hostname2 == NULL)
1363 return EAI_MEMORY;
1364 /* terminate at the delimiter */
1365 hostname2[cp - hostname] = '\0';
1366 addr = hostname2;
1367 scope = cp + 1;
1368
1369 error = explore_numeric(pai, addr, servname, res, hostname);
1370 if (error == 0) {
1371 u_int32_t scopeid;
1372
1373 for (cur = *res; cur; cur = cur->ai_next) {
1374 if (cur->ai_family != AF_INET6)
1375 continue;
1376 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
1377 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
1378 free(hostname2);
1379 freeaddrinfo(*res);
1380 *res = NULL;
1381 return(EAI_NONAME); /* XXX: is return OK? */
1382 }
1383 sin6->sin6_scope_id = scopeid;
1384 }
1385 }
1386
1387 free(hostname2);
1388
1389 if (error && *res) {
1390 freeaddrinfo(*res);
1391 *res = NULL;
1392 }
1393 return error;
1394 #endif
1395 }
1396
1397 static int
get_canonname(const struct addrinfo * pai,struct addrinfo * ai,const char * str)1398 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
1399 {
1400 if ((pai->ai_flags & AI_CANONNAME) != 0) {
1401 ai->ai_canonname = strdup(str);
1402 if (ai->ai_canonname == NULL)
1403 return EAI_MEMORY;
1404 }
1405 return 0;
1406 }
1407
1408 static struct addrinfo *
get_ai(const struct addrinfo * pai,const struct afd * afd,const char * addr)1409 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
1410 {
1411 char *p;
1412 struct addrinfo *ai;
1413 #ifdef INET6
1414 struct in6_addr mapaddr;
1415
1416 if (afd->a_af == AF_INET && (pai->ai_flags & AI_V4MAPPED) != 0) {
1417 afd = &afdl[N_INET6];
1418 _map_v4v6_address(addr, (char *)&mapaddr);
1419 addr = (char *)&mapaddr;
1420 }
1421 #endif
1422
1423 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
1424 + (afd->a_socklen));
1425 if (ai == NULL)
1426 return NULL;
1427
1428 memcpy(ai, pai, sizeof(struct addrinfo));
1429 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1430 memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1431 ai->ai_addr->sa_len = afd->a_socklen;
1432 ai->ai_addrlen = afd->a_socklen;
1433 if (ai->ai_family == PF_LOCAL) {
1434 size_t n = strnlen(addr, afd->a_addrlen);
1435
1436 ai->ai_addrlen -= afd->a_addrlen - n;
1437 ai->ai_addr->sa_len -= afd->a_addrlen - n;
1438 }
1439 ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1440 p = (char *)(void *)(ai->ai_addr);
1441 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
1442 return ai;
1443 }
1444
1445 /* XXX need to malloc() the same way we do from other functions! */
1446 static struct addrinfo *
copy_ai(const struct addrinfo * pai)1447 copy_ai(const struct addrinfo *pai)
1448 {
1449 struct addrinfo *ai;
1450 size_t l;
1451
1452 l = sizeof(*ai) + pai->ai_addrlen;
1453 if ((ai = calloc(1, l)) == NULL)
1454 return NULL;
1455 memcpy(ai, pai, sizeof(*ai));
1456 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1457 memcpy(ai->ai_addr, pai->ai_addr, pai->ai_addrlen);
1458
1459 if (pai->ai_canonname) {
1460 l = strlen(pai->ai_canonname) + 1;
1461 if ((ai->ai_canonname = malloc(l)) == NULL) {
1462 free(ai);
1463 return NULL;
1464 }
1465 strlcpy(ai->ai_canonname, pai->ai_canonname, l);
1466 } else {
1467 /* just to make sure */
1468 ai->ai_canonname = NULL;
1469 }
1470
1471 ai->ai_next = NULL;
1472
1473 return ai;
1474 }
1475
1476 static int
get_portmatch(const struct addrinfo * ai,const char * servname)1477 get_portmatch(const struct addrinfo *ai, const char *servname)
1478 {
1479
1480 /* get_port does not touch first argument when matchonly == 1. */
1481 /* LINTED const cast */
1482 return get_port((struct addrinfo *)ai, servname, 1);
1483 }
1484
1485 static int
get_port(struct addrinfo * ai,const char * servname,int matchonly)1486 get_port(struct addrinfo *ai, const char *servname, int matchonly)
1487 {
1488 const char *proto;
1489 struct servent *sp;
1490 int port, error;
1491 int allownumeric;
1492
1493 if (servname == NULL)
1494 return 0;
1495 switch (ai->ai_family) {
1496 case AF_LOCAL:
1497 /* AF_LOCAL ignores servname silently. */
1498 return (0);
1499 case AF_INET:
1500 #ifdef AF_INET6
1501 case AF_INET6:
1502 #endif
1503 break;
1504 default:
1505 return 0;
1506 }
1507
1508 switch (ai->ai_socktype) {
1509 case SOCK_RAW:
1510 return EAI_SERVICE;
1511 case SOCK_DGRAM:
1512 case SOCK_STREAM:
1513 case SOCK_SEQPACKET:
1514 allownumeric = 1;
1515 break;
1516 case ANY:
1517 switch (ai->ai_family) {
1518 case AF_INET:
1519 #ifdef AF_INET6
1520 case AF_INET6:
1521 #endif
1522 allownumeric = 1;
1523 break;
1524 default:
1525 allownumeric = 0;
1526 break;
1527 }
1528 break;
1529 default:
1530 return EAI_SOCKTYPE;
1531 }
1532
1533 error = str2number(servname, &port);
1534 if (error == 0) {
1535 if (!allownumeric)
1536 return EAI_SERVICE;
1537 if (port < 0 || port > 65535)
1538 return EAI_SERVICE;
1539 port = htons(port);
1540 } else {
1541 if (ai->ai_flags & AI_NUMERICSERV)
1542 return EAI_NONAME;
1543
1544 switch (ai->ai_protocol) {
1545 case IPPROTO_UDP:
1546 proto = "udp";
1547 break;
1548 case IPPROTO_TCP:
1549 proto = "tcp";
1550 break;
1551 case IPPROTO_SCTP:
1552 proto = "sctp";
1553 break;
1554 case IPPROTO_UDPLITE:
1555 proto = "udplite";
1556 break;
1557 default:
1558 proto = NULL;
1559 break;
1560 }
1561
1562 if ((sp = getservbyname(servname, proto)) == NULL)
1563 return EAI_SERVICE;
1564 port = sp->s_port;
1565 }
1566
1567 if (!matchonly) {
1568 switch (ai->ai_family) {
1569 case AF_INET:
1570 ((struct sockaddr_in *)(void *)
1571 ai->ai_addr)->sin_port = port;
1572 break;
1573 #ifdef INET6
1574 case AF_INET6:
1575 ((struct sockaddr_in6 *)(void *)
1576 ai->ai_addr)->sin6_port = port;
1577 break;
1578 #endif
1579 }
1580 }
1581
1582 return 0;
1583 }
1584
1585 static const struct afd *
find_afd(int af)1586 find_afd(int af)
1587 {
1588 const struct afd *afd;
1589
1590 if (af == PF_UNSPEC)
1591 return NULL;
1592 for (afd = afdl; afd->a_af; afd++) {
1593 if (afd->a_af == af)
1594 return afd;
1595 }
1596 return NULL;
1597 }
1598
1599 /*
1600 * RFC 3493: AI_ADDRCONFIG check. Determines which address families are
1601 * configured on the local system and correlates with pai->ai_family value.
1602 * If an address family is not configured on the system, it will not be
1603 * queried for. For this purpose, loopback addresses are not considered
1604 * configured addresses.
1605 *
1606 * XXX PF_UNSPEC -> PF_INET6 + PF_INET mapping needs to be in sync with
1607 * _dns_getaddrinfo.
1608 */
1609 static int
addrconfig(struct addrinfo * pai)1610 addrconfig(struct addrinfo *pai)
1611 {
1612 struct ifaddrs *ifaddrs, *ifa;
1613 struct sockaddr_in *sin;
1614 #ifdef INET6
1615 struct sockaddr_in6 *sin6;
1616 #endif
1617 int seen_inet = 0, seen_inet6 = 0;
1618
1619 if (getifaddrs(&ifaddrs) != 0)
1620 return (0);
1621
1622 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
1623 if (ifa->ifa_addr == NULL || (ifa->ifa_flags & IFF_UP) == 0)
1624 continue;
1625 switch (ifa->ifa_addr->sa_family) {
1626 case AF_INET:
1627 if (seen_inet)
1628 continue;
1629 sin = (struct sockaddr_in *)(ifa->ifa_addr);
1630 if (htonl(sin->sin_addr.s_addr) == INADDR_LOOPBACK)
1631 continue;
1632 seen_inet = 1;
1633 break;
1634 #ifdef INET6
1635 case AF_INET6:
1636 if (seen_inet6)
1637 continue;
1638 sin6 = (struct sockaddr_in6 *)(ifa->ifa_addr);
1639 if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
1640 continue;
1641 if ((ifa->ifa_flags & IFT_LOOP) != 0 &&
1642 IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
1643 continue;
1644 if (is_ifdisabled(ifa->ifa_name))
1645 continue;
1646 seen_inet6 = 1;
1647 break;
1648 #endif
1649 }
1650 }
1651 freeifaddrs(ifaddrs);
1652
1653 switch(pai->ai_family) {
1654 case AF_INET6:
1655 return (seen_inet6);
1656 case AF_INET:
1657 return (seen_inet);
1658 case AF_UNSPEC:
1659 if (seen_inet == seen_inet6)
1660 return (seen_inet);
1661 pai->ai_family = seen_inet ? AF_INET : AF_INET6;
1662 return (1);
1663 }
1664 return (1);
1665 }
1666
1667 #ifdef INET6
1668 static int
is_ifdisabled(char * name)1669 is_ifdisabled(char *name)
1670 {
1671 struct in6_ndireq nd;
1672 int fd;
1673
1674 if ((fd = _socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0)) < 0)
1675 return (-1);
1676 memset(&nd, 0, sizeof(nd));
1677 strlcpy(nd.ifname, name, sizeof(nd.ifname));
1678 if (_ioctl(fd, SIOCGIFINFO_IN6, &nd) < 0) {
1679 _close(fd);
1680 return (-1);
1681 }
1682 _close(fd);
1683 return ((nd.ndi.flags & ND6_IFF_IFDISABLED) != 0);
1684 }
1685
1686 /* convert a string to a scope identifier. XXX: IPv6 specific */
1687 static int
ip6_str2scopeid(char * scope,struct sockaddr_in6 * sin6,u_int32_t * scopeid)1688 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
1689 {
1690 u_long lscopeid;
1691 struct in6_addr *a6;
1692 char *ep;
1693
1694 a6 = &sin6->sin6_addr;
1695
1696 /* empty scopeid portion is invalid */
1697 if (*scope == '\0')
1698 return -1;
1699
1700 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) ||
1701 IN6_IS_ADDR_MC_NODELOCAL(a6)) {
1702 /*
1703 * We currently assume a one-to-one mapping between links
1704 * and interfaces, so we simply use interface indices for
1705 * like-local scopes.
1706 */
1707 *scopeid = if_nametoindex(scope);
1708 if (*scopeid == 0)
1709 goto trynumeric;
1710 return 0;
1711 }
1712
1713 /* still unclear about literal, allow numeric only - placeholder */
1714 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1715 goto trynumeric;
1716 if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1717 goto trynumeric;
1718 else
1719 goto trynumeric; /* global */
1720
1721 /* try to convert to a numeric id as a last resort */
1722 trynumeric:
1723 errno = 0;
1724 lscopeid = strtoul(scope, &ep, 10);
1725 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
1726 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
1727 return 0;
1728 else
1729 return -1;
1730 }
1731 #endif
1732
1733
1734 #ifdef NS_CACHING
1735 static int
addrinfo_id_func(char * buffer,size_t * buffer_size,va_list ap,void * cache_mdata)1736 addrinfo_id_func(char *buffer, size_t *buffer_size, va_list ap,
1737 void *cache_mdata)
1738 {
1739 res_state statp;
1740 u_long res_options;
1741
1742 const int op_id = 0; /* identifies the getaddrinfo for the cache */
1743 char *hostname;
1744 struct addrinfo *hints;
1745
1746 char *p;
1747 int ai_flags, ai_family, ai_socktype, ai_protocol;
1748 size_t desired_size, size;
1749
1750 statp = __res_state();
1751 res_options = statp->options & (RES_RECURSE | RES_DEFNAMES |
1752 RES_DNSRCH | RES_NOALIASES | RES_USE_INET6);
1753
1754 hostname = va_arg(ap, char *);
1755 hints = va_arg(ap, struct addrinfo *);
1756
1757 desired_size = sizeof(res_options) + sizeof(int) + sizeof(int) * 4;
1758 if (hostname != NULL) {
1759 size = strlen(hostname);
1760 desired_size += size + 1;
1761 } else
1762 size = 0;
1763
1764 if (desired_size > *buffer_size) {
1765 *buffer_size = desired_size;
1766 return (NS_RETURN);
1767 }
1768
1769 if (hints == NULL)
1770 ai_flags = ai_family = ai_socktype = ai_protocol = 0;
1771 else {
1772 ai_flags = hints->ai_flags;
1773 ai_family = hints->ai_family;
1774 ai_socktype = hints->ai_socktype;
1775 ai_protocol = hints->ai_protocol;
1776 }
1777
1778 p = buffer;
1779 memcpy(p, &res_options, sizeof(res_options));
1780 p += sizeof(res_options);
1781
1782 memcpy(p, &op_id, sizeof(int));
1783 p += sizeof(int);
1784
1785 memcpy(p, &ai_flags, sizeof(int));
1786 p += sizeof(int);
1787
1788 memcpy(p, &ai_family, sizeof(int));
1789 p += sizeof(int);
1790
1791 memcpy(p, &ai_socktype, sizeof(int));
1792 p += sizeof(int);
1793
1794 memcpy(p, &ai_protocol, sizeof(int));
1795 p += sizeof(int);
1796
1797 if (hostname != NULL)
1798 memcpy(p, hostname, size);
1799
1800 *buffer_size = desired_size;
1801 return (NS_SUCCESS);
1802 }
1803
1804 static int
addrinfo_marshal_func(char * buffer,size_t * buffer_size,void * retval,va_list ap,void * cache_mdata)1805 addrinfo_marshal_func(char *buffer, size_t *buffer_size, void *retval,
1806 va_list ap, void *cache_mdata)
1807 {
1808 struct addrinfo *ai, *cai;
1809 char *p;
1810 size_t desired_size, size, ai_size;
1811
1812 ai = *((struct addrinfo **)retval);
1813
1814 desired_size = sizeof(size_t);
1815 ai_size = 0;
1816 for (cai = ai; cai != NULL; cai = cai->ai_next) {
1817 desired_size += sizeof(struct addrinfo) + cai->ai_addrlen;
1818 if (cai->ai_canonname != NULL)
1819 desired_size += sizeof(size_t) +
1820 strlen(cai->ai_canonname);
1821 ++ai_size;
1822 }
1823
1824 if (desired_size > *buffer_size) {
1825 /* this assignment is here for future use */
1826 errno = ERANGE;
1827 *buffer_size = desired_size;
1828 return (NS_RETURN);
1829 }
1830
1831 memset(buffer, 0, desired_size);
1832 p = buffer;
1833
1834 memcpy(p, &ai_size, sizeof(size_t));
1835 p += sizeof(size_t);
1836 for (cai = ai; cai != NULL; cai = cai->ai_next) {
1837 memcpy(p, cai, sizeof(struct addrinfo));
1838 p += sizeof(struct addrinfo);
1839
1840 memcpy(p, cai->ai_addr, cai->ai_addrlen);
1841 p += cai->ai_addrlen;
1842
1843 if (cai->ai_canonname != NULL) {
1844 size = strlen(cai->ai_canonname);
1845 memcpy(p, &size, sizeof(size_t));
1846 p += sizeof(size_t);
1847
1848 memcpy(p, cai->ai_canonname, size);
1849 p += size;
1850 }
1851 }
1852
1853 return (NS_SUCCESS);
1854 }
1855
1856 static int
addrinfo_unmarshal_func(char * buffer,size_t buffer_size,void * retval,va_list ap,void * cache_mdata)1857 addrinfo_unmarshal_func(char *buffer, size_t buffer_size, void *retval,
1858 va_list ap, void *cache_mdata)
1859 {
1860 struct addrinfo new_ai, *result, *sentinel, *lasts;
1861
1862 char *p;
1863 size_t ai_size, ai_i, size;
1864
1865 p = buffer;
1866 memcpy(&ai_size, p, sizeof(size_t));
1867 p += sizeof(size_t);
1868
1869 result = NULL;
1870 lasts = NULL;
1871 for (ai_i = 0; ai_i < ai_size; ++ai_i) {
1872 memcpy(&new_ai, p, sizeof(struct addrinfo));
1873 p += sizeof(struct addrinfo);
1874 size = new_ai.ai_addrlen + sizeof(struct addrinfo) +
1875 _ALIGNBYTES;
1876
1877 sentinel = calloc(1, size);
1878
1879 memcpy(sentinel, &new_ai, sizeof(struct addrinfo));
1880 sentinel->ai_addr = (struct sockaddr *)_ALIGN((char *)sentinel +
1881 sizeof(struct addrinfo));
1882
1883 memcpy(sentinel->ai_addr, p, new_ai.ai_addrlen);
1884 p += new_ai.ai_addrlen;
1885
1886 if (new_ai.ai_canonname != NULL) {
1887 memcpy(&size, p, sizeof(size_t));
1888 p += sizeof(size_t);
1889
1890 sentinel->ai_canonname = calloc(1, size + 1);
1891
1892 memcpy(sentinel->ai_canonname, p, size);
1893 p += size;
1894 }
1895
1896 if (result == NULL) {
1897 result = sentinel;
1898 lasts = sentinel;
1899 } else {
1900 lasts->ai_next = sentinel;
1901 lasts = sentinel;
1902 }
1903 }
1904
1905 *((struct addrinfo **)retval) = result;
1906 return (NS_SUCCESS);
1907 }
1908 #endif /* NS_CACHING */
1909
1910 /*
1911 * FQDN hostname, DNS lookup
1912 */
1913 static int
explore_fqdn(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res)1914 explore_fqdn(const struct addrinfo *pai, const char *hostname,
1915 const char *servname, struct addrinfo **res)
1916 {
1917 struct addrinfo *result;
1918 struct addrinfo *cur;
1919 int error = 0;
1920
1921 #ifdef NS_CACHING
1922 static const nss_cache_info cache_info =
1923 NS_COMMON_CACHE_INFO_INITIALIZER(
1924 hosts, NULL, addrinfo_id_func, addrinfo_marshal_func,
1925 addrinfo_unmarshal_func);
1926 #endif
1927 static const ns_dtab dtab[] = {
1928 NS_FILES_CB(_files_getaddrinfo, NULL)
1929 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
1930 NS_NIS_CB(_yp_getaddrinfo, NULL)
1931 #ifdef NS_CACHING
1932 NS_CACHE_CB(&cache_info)
1933 #endif
1934 { 0 }
1935 };
1936
1937 result = NULL;
1938
1939 /*
1940 * if the servname does not match socktype/protocol, ignore it.
1941 */
1942 if (get_portmatch(pai, servname) != 0)
1943 return 0;
1944
1945 switch (_nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
1946 default_dns_files, hostname, pai)) {
1947 case NS_TRYAGAIN:
1948 error = EAI_AGAIN;
1949 goto free;
1950 case NS_UNAVAIL:
1951 error = EAI_FAIL;
1952 goto free;
1953 case NS_NOTFOUND:
1954 error = EAI_NONAME;
1955 goto free;
1956 case NS_SUCCESS:
1957 error = 0;
1958 for (cur = result; cur; cur = cur->ai_next) {
1959 GET_PORT(cur, servname);
1960 /* canonname should be filled already */
1961 }
1962 break;
1963 }
1964
1965 *res = result;
1966
1967 return 0;
1968
1969 free:
1970 if (result)
1971 freeaddrinfo(result);
1972 return error;
1973 }
1974
1975 #ifdef DEBUG
1976 static const char AskedForGot[] =
1977 "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1978 #endif
1979
1980 static struct addrinfo *
getanswer(const querybuf * answer,int anslen,const char * qname,int qtype,const struct addrinfo * pai,res_state res)1981 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
1982 const struct addrinfo *pai, res_state res)
1983 {
1984 struct addrinfo sentinel, *cur;
1985 struct addrinfo ai;
1986 const struct afd *afd;
1987 char *canonname;
1988 const HEADER *hp;
1989 const u_char *cp;
1990 int n;
1991 const u_char *eom;
1992 char *bp, *ep;
1993 int type, class, ancount, qdcount;
1994 int haveanswer, had_error;
1995 char tbuf[MAXDNAME];
1996 int (*name_ok)(const char *);
1997 char hostbuf[8*1024];
1998
1999 memset(&sentinel, 0, sizeof(sentinel));
2000 cur = &sentinel;
2001
2002 canonname = NULL;
2003 eom = answer->buf + anslen;
2004 switch (qtype) {
2005 case T_A:
2006 case T_AAAA:
2007 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
2008 name_ok = res_hnok;
2009 break;
2010 default:
2011 return (NULL); /* XXX should be abort(); */
2012 }
2013 /*
2014 * find first satisfactory answer
2015 */
2016 hp = &answer->hdr;
2017 ancount = ntohs(hp->ancount);
2018 qdcount = ntohs(hp->qdcount);
2019 bp = hostbuf;
2020 ep = hostbuf + sizeof hostbuf;
2021 cp = answer->buf + HFIXEDSZ;
2022 if (qdcount != 1) {
2023 RES_SET_H_ERRNO(res, NO_RECOVERY);
2024 return (NULL);
2025 }
2026 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
2027 if ((n < 0) || !(*name_ok)(bp)) {
2028 RES_SET_H_ERRNO(res, NO_RECOVERY);
2029 return (NULL);
2030 }
2031 cp += n + QFIXEDSZ;
2032 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
2033 /* res_send() has already verified that the query name is the
2034 * same as the one we sent; this just gets the expanded name
2035 * (i.e., with the succeeding search-domain tacked on).
2036 */
2037 n = strlen(bp) + 1; /* for the \0 */
2038 if (n >= MAXHOSTNAMELEN) {
2039 RES_SET_H_ERRNO(res, NO_RECOVERY);
2040 return (NULL);
2041 }
2042 canonname = bp;
2043 bp += n;
2044 /* The qname can be abbreviated, but h_name is now absolute. */
2045 qname = canonname;
2046 }
2047 haveanswer = 0;
2048 had_error = 0;
2049 while (ancount-- > 0 && cp < eom && !had_error) {
2050 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
2051 if ((n < 0) || !(*name_ok)(bp)) {
2052 had_error++;
2053 continue;
2054 }
2055 cp += n; /* name */
2056 type = _getshort(cp);
2057 cp += INT16SZ; /* type */
2058 class = _getshort(cp);
2059 cp += INT16SZ + INT32SZ; /* class, TTL */
2060 n = _getshort(cp);
2061 cp += INT16SZ; /* len */
2062 if (class != C_IN) {
2063 /* XXX - debug? syslog? */
2064 cp += n;
2065 continue; /* XXX - had_error++ ? */
2066 }
2067 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
2068 type == T_CNAME) {
2069 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
2070 if ((n < 0) || !(*name_ok)(tbuf)) {
2071 had_error++;
2072 continue;
2073 }
2074 cp += n;
2075 /* Get canonical name. */
2076 n = strlen(tbuf) + 1; /* for the \0 */
2077 if (n > ep - bp || n >= MAXHOSTNAMELEN) {
2078 had_error++;
2079 continue;
2080 }
2081 strlcpy(bp, tbuf, ep - bp);
2082 canonname = bp;
2083 bp += n;
2084 continue;
2085 }
2086 if (qtype == T_ANY) {
2087 if (!(type == T_A || type == T_AAAA)) {
2088 cp += n;
2089 continue;
2090 }
2091 } else if (type != qtype) {
2092 #ifdef DEBUG
2093 if (type != T_KEY && type != T_SIG &&
2094 type != ns_t_dname)
2095 syslog(LOG_NOTICE|LOG_AUTH,
2096 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
2097 qname, p_class(C_IN), p_type(qtype),
2098 p_type(type));
2099 #endif
2100 cp += n;
2101 continue; /* XXX - had_error++ ? */
2102 }
2103 switch (type) {
2104 case T_A:
2105 case T_AAAA:
2106 if (strcasecmp(canonname, bp) != 0) {
2107 #ifdef DEBUG
2108 syslog(LOG_NOTICE|LOG_AUTH,
2109 AskedForGot, canonname, bp);
2110 #endif
2111 cp += n;
2112 continue; /* XXX - had_error++ ? */
2113 }
2114 if (type == T_A && n != INADDRSZ) {
2115 cp += n;
2116 continue;
2117 }
2118 if (type == T_AAAA && n != IN6ADDRSZ) {
2119 cp += n;
2120 continue;
2121 }
2122 #ifdef FILTER_V4MAPPED
2123 if (type == T_AAAA) {
2124 struct in6_addr in6;
2125 memcpy(&in6, cp, sizeof(in6));
2126 if (IN6_IS_ADDR_V4MAPPED(&in6)) {
2127 cp += n;
2128 continue;
2129 }
2130 }
2131 #endif
2132 if (!haveanswer) {
2133 int nn;
2134
2135 canonname = bp;
2136 nn = strlen(bp) + 1; /* for the \0 */
2137 bp += nn;
2138 }
2139
2140 /* don't overwrite pai */
2141 ai = *pai;
2142 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
2143 afd = find_afd(ai.ai_family);
2144 if (afd == NULL) {
2145 cp += n;
2146 continue;
2147 }
2148 cur->ai_next = get_ai(&ai, afd, (const char *)cp);
2149 if (cur->ai_next == NULL)
2150 had_error++;
2151 while (cur && cur->ai_next)
2152 cur = cur->ai_next;
2153 cp += n;
2154 break;
2155 default:
2156 abort();
2157 }
2158 if (!had_error)
2159 haveanswer++;
2160 }
2161 if (haveanswer) {
2162 #if defined(RESOLVSORT)
2163 /*
2164 * We support only IPv4 address for backward
2165 * compatibility against gethostbyname(3).
2166 */
2167 if (res->nsort && qtype == T_A) {
2168 if (addr4sort(&sentinel, res) < 0) {
2169 freeaddrinfo(sentinel.ai_next);
2170 RES_SET_H_ERRNO(res, NO_RECOVERY);
2171 return NULL;
2172 }
2173 }
2174 #endif /*RESOLVSORT*/
2175 if (!canonname)
2176 (void)get_canonname(pai, sentinel.ai_next, qname);
2177 else
2178 (void)get_canonname(pai, sentinel.ai_next, canonname);
2179 RES_SET_H_ERRNO(res, NETDB_SUCCESS);
2180 return sentinel.ai_next;
2181 }
2182
2183 /*
2184 * We could have walked a CNAME chain, but the ultimate target
2185 * may not have what we looked for.
2186 */
2187 RES_SET_H_ERRNO(res, ntohs(hp->ancount) > 0 ? NO_DATA : NO_RECOVERY);
2188 return NULL;
2189 }
2190
2191 #ifdef RESOLVSORT
2192 struct addr_ptr {
2193 struct addrinfo *ai;
2194 int aval;
2195 };
2196
2197 static int
addr4sort(struct addrinfo * sentinel,res_state res)2198 addr4sort(struct addrinfo *sentinel, res_state res)
2199 {
2200 struct addrinfo *ai;
2201 struct addr_ptr *addrs, addr;
2202 struct sockaddr_in *sin;
2203 int naddrs, i, j;
2204 int needsort = 0;
2205
2206 if (!sentinel)
2207 return -1;
2208 naddrs = 0;
2209 for (ai = sentinel->ai_next; ai; ai = ai->ai_next)
2210 naddrs++;
2211 if (naddrs < 2)
2212 return 0; /* We don't need sorting. */
2213 if ((addrs = malloc(sizeof(struct addr_ptr) * naddrs)) == NULL)
2214 return -1;
2215 i = 0;
2216 for (ai = sentinel->ai_next; ai; ai = ai->ai_next) {
2217 sin = (struct sockaddr_in *)ai->ai_addr;
2218 for (j = 0; (unsigned)j < res->nsort; j++) {
2219 if (res->sort_list[j].addr.s_addr ==
2220 (sin->sin_addr.s_addr & res->sort_list[j].mask))
2221 break;
2222 }
2223 addrs[i].ai = ai;
2224 addrs[i].aval = j;
2225 if (needsort == 0 && i > 0 && j < addrs[i - 1].aval)
2226 needsort = i;
2227 i++;
2228 }
2229 if (!needsort) {
2230 free(addrs);
2231 return 0;
2232 }
2233
2234 while (needsort < naddrs) {
2235 for (j = needsort - 1; j >= 0; j--) {
2236 if (addrs[j].aval > addrs[j+1].aval) {
2237 addr = addrs[j];
2238 addrs[j] = addrs[j + 1];
2239 addrs[j + 1] = addr;
2240 } else
2241 break;
2242 }
2243 needsort++;
2244 }
2245
2246 ai = sentinel;
2247 for (i = 0; i < naddrs; ++i) {
2248 ai->ai_next = addrs[i].ai;
2249 ai = ai->ai_next;
2250 }
2251 ai->ai_next = NULL;
2252 free(addrs);
2253 return 0;
2254 }
2255 #endif /*RESOLVSORT*/
2256
2257 /*ARGSUSED*/
2258 static int
_dns_getaddrinfo(void * rv,void * cb_data,va_list ap)2259 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
2260 {
2261 struct addrinfo *ai, ai0;
2262 querybuf *buf, *buf2;
2263 const char *hostname;
2264 const struct addrinfo *pai;
2265 struct addrinfo sentinel, *cur;
2266 struct res_target q, q2;
2267 res_state res;
2268
2269 ai = NULL;
2270
2271 hostname = va_arg(ap, char *);
2272 pai = va_arg(ap, const struct addrinfo *);
2273
2274 memset(&q, 0, sizeof(q));
2275 memset(&q2, 0, sizeof(q2));
2276 memset(&sentinel, 0, sizeof(sentinel));
2277 cur = &sentinel;
2278
2279 res = __res_state();
2280
2281 buf = malloc(sizeof(*buf));
2282 if (!buf) {
2283 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2284 return NS_NOTFOUND;
2285 }
2286 buf2 = malloc(sizeof(*buf2));
2287 if (!buf2) {
2288 free(buf);
2289 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2290 return NS_NOTFOUND;
2291 }
2292
2293 if (pai->ai_family == AF_INET6 &&
2294 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) {
2295 ai0 = *pai;
2296 ai0.ai_family = AF_UNSPEC;
2297 pai = &ai0;
2298 }
2299
2300 switch (pai->ai_family) {
2301 case AF_UNSPEC:
2302 q.name = hostname;
2303 q.qclass = C_IN;
2304 q.qtype = T_A;
2305 q.answer = buf->buf;
2306 q.anslen = sizeof(buf->buf);
2307 q.next = &q2;
2308 q2.name = hostname;
2309 q2.qclass = C_IN;
2310 q2.qtype = T_AAAA;
2311 q2.answer = buf2->buf;
2312 q2.anslen = sizeof(buf2->buf);
2313 break;
2314 case AF_INET:
2315 q.name = hostname;
2316 q.qclass = C_IN;
2317 q.qtype = T_A;
2318 q.answer = buf->buf;
2319 q.anslen = sizeof(buf->buf);
2320 break;
2321 case AF_INET6:
2322 q.name = hostname;
2323 q.qclass = C_IN;
2324 q.qtype = T_AAAA;
2325 q.answer = buf->buf;
2326 q.anslen = sizeof(buf->buf);
2327 break;
2328 default:
2329 free(buf);
2330 free(buf2);
2331 return NS_UNAVAIL;
2332 }
2333
2334 if ((res->options & RES_INIT) == 0 && res_ninit(res) == -1) {
2335 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2336 free(buf);
2337 free(buf2);
2338 return NS_NOTFOUND;
2339 }
2340
2341 if (res_searchN(hostname, &q, res) < 0) {
2342 free(buf);
2343 free(buf2);
2344 return NS_NOTFOUND;
2345 }
2346 /* prefer IPv6 */
2347 if (q.next) {
2348 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai, res);
2349 if (ai != NULL) {
2350 cur->ai_next = ai;
2351 while (cur && cur->ai_next)
2352 cur = cur->ai_next;
2353 }
2354 }
2355 if (ai == NULL || pai->ai_family != AF_UNSPEC ||
2356 (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) != AI_V4MAPPED) {
2357 ai = getanswer(buf, q.n, q.name, q.qtype, pai, res);
2358 if (ai != NULL)
2359 cur->ai_next = ai;
2360 }
2361 free(buf);
2362 free(buf2);
2363 if (sentinel.ai_next == NULL)
2364 switch (res->res_h_errno) {
2365 case HOST_NOT_FOUND:
2366 case NO_DATA:
2367 return NS_NOTFOUND;
2368 case TRY_AGAIN:
2369 return NS_TRYAGAIN;
2370 default:
2371 return NS_UNAVAIL;
2372 }
2373 *((struct addrinfo **)rv) = sentinel.ai_next;
2374 return NS_SUCCESS;
2375 }
2376
2377 static void
_sethtent(FILE ** hostf)2378 _sethtent(FILE **hostf)
2379 {
2380 if (!*hostf)
2381 *hostf = fopen(_PATH_HOSTS, "re");
2382 else
2383 rewind(*hostf);
2384 }
2385
2386 static void
_endhtent(FILE ** hostf)2387 _endhtent(FILE **hostf)
2388 {
2389 if (*hostf) {
2390 (void) fclose(*hostf);
2391 *hostf = NULL;
2392 }
2393 }
2394
2395 static struct addrinfo *
_gethtent(FILE ** hostf,const char * name,const struct addrinfo * pai)2396 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai)
2397 {
2398 char *p;
2399 char *cp, *tname, *cname;
2400 struct addrinfo hints, *res0, *res;
2401 int error;
2402 const char *addr;
2403 char hostbuf[8*1024];
2404
2405 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re")))
2406 return (NULL);
2407 again:
2408 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf)))
2409 return (NULL);
2410 if (*p == '#')
2411 goto again;
2412 cp = strpbrk(p, "#\n");
2413 if (cp != NULL)
2414 *cp = '\0';
2415 if (!(cp = strpbrk(p, " \t")))
2416 goto again;
2417 *cp++ = '\0';
2418 addr = p;
2419 cname = NULL;
2420 /* if this is not something we're looking for, skip it. */
2421 while (cp && *cp) {
2422 if (*cp == ' ' || *cp == '\t') {
2423 cp++;
2424 continue;
2425 }
2426 tname = cp;
2427 if (cname == NULL)
2428 cname = cp;
2429 if ((cp = strpbrk(cp, " \t")) != NULL)
2430 *cp++ = '\0';
2431 if (strcasecmp(name, tname) == 0)
2432 goto found;
2433 }
2434 goto again;
2435
2436 found:
2437 /* we should not glob socktype/protocol here */
2438 memset(&hints, 0, sizeof(hints));
2439 hints.ai_family = pai->ai_family;
2440 hints.ai_socktype = SOCK_DGRAM;
2441 hints.ai_protocol = 0;
2442 hints.ai_flags = AI_NUMERICHOST;
2443 if (pai->ai_family == AF_INET6 &&
2444 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED)
2445 hints.ai_flags |= AI_V4MAPPED;
2446 error = getaddrinfo(addr, "0", &hints, &res0);
2447 if (error)
2448 goto again;
2449 #ifdef FILTER_V4MAPPED
2450 /* XXX should check all items in the chain */
2451 if (res0->ai_family == AF_INET6 &&
2452 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)res0->ai_addr)->sin6_addr)) {
2453 freeaddrinfo(res0);
2454 goto again;
2455 }
2456 #endif
2457 for (res = res0; res; res = res->ai_next) {
2458 /* cover it up */
2459 res->ai_flags = pai->ai_flags;
2460 res->ai_socktype = pai->ai_socktype;
2461 res->ai_protocol = pai->ai_protocol;
2462
2463 if (pai->ai_flags & AI_CANONNAME) {
2464 if (get_canonname(pai, res, cname) != 0) {
2465 freeaddrinfo(res0);
2466 goto again;
2467 }
2468 }
2469 }
2470 return res0;
2471 }
2472
2473 static struct addrinfo *
_getht(FILE ** hostf,const char * name,const struct addrinfo * pai,struct addrinfo * cur)2474 _getht(FILE **hostf, const char *name, const struct addrinfo *pai,
2475 struct addrinfo *cur)
2476 {
2477 struct addrinfo *p;
2478
2479 while ((p = _gethtent(hostf, name, pai)) != NULL) {
2480 cur->ai_next = p;
2481 while (cur && cur->ai_next)
2482 cur = cur->ai_next;
2483 }
2484 return (cur);
2485 }
2486
2487 /*ARGSUSED*/
2488 static int
_files_getaddrinfo(void * rv,void * cb_data,va_list ap)2489 _files_getaddrinfo(void *rv, void *cb_data, va_list ap)
2490 {
2491 const char *name;
2492 const struct addrinfo *pai;
2493 struct addrinfo sentinel, *cur;
2494 FILE *hostf = NULL;
2495
2496 name = va_arg(ap, char *);
2497 pai = va_arg(ap, struct addrinfo *);
2498
2499 memset(&sentinel, 0, sizeof(sentinel));
2500 cur = &sentinel;
2501
2502 _sethtent(&hostf);
2503 if (pai->ai_family == AF_INET6 &&
2504 (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) == AI_V4MAPPED) {
2505 struct addrinfo ai0 = *pai;
2506
2507 ai0.ai_flags &= ~AI_V4MAPPED;
2508 cur = _getht(&hostf, name, &ai0, cur);
2509 if (sentinel.ai_next == NULL) {
2510 _sethtent(&hostf);
2511 ai0.ai_flags |= AI_V4MAPPED;
2512 cur = _getht(&hostf, name, &ai0, cur);
2513 }
2514 } else
2515 cur = _getht(&hostf, name, pai, cur);
2516 _endhtent(&hostf);
2517
2518 *((struct addrinfo **)rv) = sentinel.ai_next;
2519 if (sentinel.ai_next == NULL)
2520 return NS_NOTFOUND;
2521 return NS_SUCCESS;
2522 }
2523
2524 #ifdef YP
2525 /*ARGSUSED*/
2526 static struct addrinfo *
_yphostent(char * line,const struct addrinfo * pai)2527 _yphostent(char *line, const struct addrinfo *pai)
2528 {
2529 struct addrinfo sentinel, *cur;
2530 struct addrinfo hints, *res, *res0;
2531 int error;
2532 char *p = line;
2533 const char *addr, *canonname;
2534 char *nextline;
2535 char *cp;
2536
2537 addr = canonname = NULL;
2538
2539 memset(&sentinel, 0, sizeof(sentinel));
2540 cur = &sentinel;
2541
2542 nextline:
2543 /* terminate line */
2544 cp = strchr(p, '\n');
2545 if (cp) {
2546 *cp++ = '\0';
2547 nextline = cp;
2548 } else
2549 nextline = NULL;
2550
2551 cp = strpbrk(p, " \t");
2552 if (cp == NULL) {
2553 if (canonname == NULL)
2554 return (NULL);
2555 else
2556 goto done;
2557 }
2558 *cp++ = '\0';
2559
2560 addr = p;
2561
2562 while (cp && *cp) {
2563 if (*cp == ' ' || *cp == '\t') {
2564 cp++;
2565 continue;
2566 }
2567 if (!canonname)
2568 canonname = cp;
2569 if ((cp = strpbrk(cp, " \t")) != NULL)
2570 *cp++ = '\0';
2571 }
2572
2573 hints = *pai;
2574 hints.ai_flags = AI_NUMERICHOST;
2575 if (pai->ai_family == AF_INET6 &&
2576 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED)
2577 hints.ai_flags |= AI_V4MAPPED;
2578 error = getaddrinfo(addr, NULL, &hints, &res0);
2579 if (error == 0) {
2580 for (res = res0; res; res = res->ai_next) {
2581 /* cover it up */
2582 res->ai_flags = pai->ai_flags;
2583
2584 if (pai->ai_flags & AI_CANONNAME)
2585 (void)get_canonname(pai, res, canonname);
2586 }
2587 } else
2588 res0 = NULL;
2589 if (res0) {
2590 cur->ai_next = res0;
2591 while (cur && cur->ai_next)
2592 cur = cur->ai_next;
2593 }
2594
2595 if (nextline) {
2596 p = nextline;
2597 goto nextline;
2598 }
2599
2600 done:
2601 return sentinel.ai_next;
2602 }
2603
2604 /*ARGSUSED*/
2605 static int
_yp_getaddrinfo(void * rv,void * cb_data,va_list ap)2606 _yp_getaddrinfo(void *rv, void *cb_data, va_list ap)
2607 {
2608 struct addrinfo sentinel, *cur;
2609 struct addrinfo *ai = NULL;
2610 char *ypbuf;
2611 int ypbuflen, r;
2612 const char *name;
2613 const struct addrinfo *pai;
2614 char *ypdomain;
2615
2616 if (_yp_check(&ypdomain) == 0)
2617 return NS_UNAVAIL;
2618
2619 name = va_arg(ap, char *);
2620 pai = va_arg(ap, const struct addrinfo *);
2621
2622 memset(&sentinel, 0, sizeof(sentinel));
2623 cur = &sentinel;
2624
2625 /* ipnodes.byname can hold both IPv4/v6 */
2626 r = yp_match(ypdomain, "ipnodes.byname", name,
2627 (int)strlen(name), &ypbuf, &ypbuflen);
2628 if (r == 0) {
2629 ai = _yphostent(ypbuf, pai);
2630 if (ai) {
2631 cur->ai_next = ai;
2632 while (cur && cur->ai_next)
2633 cur = cur->ai_next;
2634 }
2635 free(ypbuf);
2636 }
2637
2638 if (ai != NULL) {
2639 struct sockaddr_in6 *sin6;
2640
2641 switch (ai->ai_family) {
2642 case AF_INET:
2643 goto done;
2644 case AF_INET6:
2645 sin6 = (struct sockaddr_in6 *)ai->ai_addr;
2646 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
2647 goto done;
2648 break;
2649 }
2650 }
2651
2652 /* hosts.byname is only for IPv4 (Solaris8) */
2653 if (pai->ai_family == AF_UNSPEC || pai->ai_family == AF_INET ||
2654 ((pai->ai_family == AF_INET6 &&
2655 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) &&
2656 (ai == NULL || (pai->ai_flags & AI_ALL) == AI_ALL))) {
2657 r = yp_match(ypdomain, "hosts.byname", name,
2658 (int)strlen(name), &ypbuf, &ypbuflen);
2659 if (r == 0) {
2660 struct addrinfo ai4;
2661
2662 ai4 = *pai;
2663 if (pai->ai_family == AF_UNSPEC)
2664 ai4.ai_family = AF_INET;
2665 ai = _yphostent(ypbuf, &ai4);
2666 if (ai) {
2667 cur->ai_next = ai;
2668 while (cur && cur->ai_next)
2669 cur = cur->ai_next;
2670 }
2671 free(ypbuf);
2672 }
2673 }
2674
2675 done:
2676 if (sentinel.ai_next == NULL) {
2677 RES_SET_H_ERRNO(__res_state(), HOST_NOT_FOUND);
2678 return NS_NOTFOUND;
2679 }
2680 *((struct addrinfo **)rv) = sentinel.ai_next;
2681 return NS_SUCCESS;
2682 }
2683 #endif
2684
2685 /* resolver logic */
2686
2687 /*
2688 * Formulate a normal query, send, and await answer.
2689 * Returned answer is placed in supplied buffer "answer".
2690 * Perform preliminary check of answer, returning success only
2691 * if no error is indicated and the answer count is nonzero.
2692 * Return the size of the response on success, -1 on error.
2693 * Error number is left in h_errno.
2694 *
2695 * Caller must parse answer and determine whether it answers the question.
2696 */
2697 static int
res_queryN(const char * name,struct res_target * target,res_state res)2698 res_queryN(const char *name, struct res_target *target, res_state res)
2699 {
2700 u_char *buf;
2701 HEADER *hp;
2702 int n;
2703 u_int oflags;
2704 struct res_target *t;
2705 int rcode;
2706 int ancount;
2707
2708 rcode = NOERROR;
2709 ancount = 0;
2710
2711 buf = malloc(MAXPACKET);
2712 if (!buf) {
2713 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2714 return -1;
2715 }
2716
2717 for (t = target; t; t = t->next) {
2718 int class, type;
2719 u_char *answer;
2720 int anslen;
2721
2722 hp = (HEADER *)(void *)t->answer;
2723
2724 /* make it easier... */
2725 class = t->qclass;
2726 type = t->qtype;
2727 answer = t->answer;
2728 anslen = t->anslen;
2729
2730 oflags = res->_flags;
2731
2732 again:
2733 hp->rcode = NOERROR; /* default */
2734
2735 #ifdef DEBUG
2736 if (res->options & RES_DEBUG)
2737 printf(";; res_query(%s, %d, %d)\n", name, class, type);
2738 #endif
2739
2740 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
2741 buf, MAXPACKET);
2742 if (n > 0 && (res->_flags & RES_F_EDNS0ERR) == 0 &&
2743 (res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0U)
2744 n = res_nopt(res, n, buf, MAXPACKET, anslen);
2745 if (n <= 0) {
2746 #ifdef DEBUG
2747 if (res->options & RES_DEBUG)
2748 printf(";; res_query: mkquery failed\n");
2749 #endif
2750 free(buf);
2751 RES_SET_H_ERRNO(res, NO_RECOVERY);
2752 return (n);
2753 }
2754 n = res_nsend(res, buf, n, answer, anslen);
2755 if (n < 0) {
2756 /*
2757 * if the query choked with EDNS0, retry
2758 * without EDNS0
2759 */
2760 if ((res->options & (RES_USE_EDNS0|RES_USE_DNSSEC))
2761 != 0U &&
2762 ((oflags ^ res->_flags) & RES_F_EDNS0ERR) != 0) {
2763 res->_flags |= RES_F_EDNS0ERR;
2764 if (res->options & RES_DEBUG)
2765 printf(";; res_nquery: retry without EDNS0\n");
2766 goto again;
2767 }
2768 rcode = hp->rcode; /* record most recent error */
2769 #ifdef DEBUG
2770 if (res->options & RES_DEBUG)
2771 printf(";; res_query: send error\n");
2772 #endif
2773 continue;
2774 }
2775
2776 if (n > anslen)
2777 hp->rcode = FORMERR; /* XXX not very informative */
2778 if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
2779 rcode = hp->rcode; /* record most recent error */
2780 #ifdef DEBUG
2781 if (res->options & RES_DEBUG)
2782 printf(";; rcode = %u, ancount=%u\n", hp->rcode,
2783 ntohs(hp->ancount));
2784 #endif
2785 continue;
2786 }
2787
2788 ancount += ntohs(hp->ancount);
2789
2790 t->n = n;
2791 }
2792
2793 free(buf);
2794
2795 if (ancount == 0) {
2796 switch (rcode) {
2797 case NXDOMAIN:
2798 RES_SET_H_ERRNO(res, HOST_NOT_FOUND);
2799 break;
2800 case SERVFAIL:
2801 RES_SET_H_ERRNO(res, TRY_AGAIN);
2802 break;
2803 case NOERROR:
2804 RES_SET_H_ERRNO(res, NO_DATA);
2805 break;
2806 case FORMERR:
2807 case NOTIMP:
2808 case REFUSED:
2809 default:
2810 RES_SET_H_ERRNO(res, NO_RECOVERY);
2811 break;
2812 }
2813 return (-1);
2814 }
2815 return (ancount);
2816 }
2817
2818 /*
2819 * Formulate a normal query, send, and retrieve answer in supplied buffer.
2820 * Return the size of the response on success, -1 on error.
2821 * If enabled, implement search rules until answer or unrecoverable failure
2822 * is detected. Error code, if any, is left in h_errno.
2823 */
2824 static int
res_searchN(const char * name,struct res_target * target,res_state res)2825 res_searchN(const char *name, struct res_target *target, res_state res)
2826 {
2827 const char *cp, * const *domain;
2828 HEADER *hp = (HEADER *)(void *)target->answer; /*XXX*/
2829 u_int dots;
2830 int trailing_dot, ret, saved_herrno;
2831 int got_nodata = 0, got_servfail = 0, root_on_list = 0;
2832 int tried_as_is = 0;
2833 int searched = 0;
2834 char abuf[MAXDNAME];
2835
2836 errno = 0;
2837 RES_SET_H_ERRNO(res, HOST_NOT_FOUND); /* default, if we never query */
2838 dots = 0;
2839 for (cp = name; *cp; cp++)
2840 dots += (*cp == '.');
2841 trailing_dot = 0;
2842 if (cp > name && *--cp == '.')
2843 trailing_dot++;
2844
2845 /*
2846 * if there aren't any dots, it could be a user-level alias
2847 */
2848 if (!dots &&
2849 (cp = res_hostalias(res, name, abuf, sizeof(abuf))) != NULL)
2850 return (res_queryN(cp, target, res));
2851
2852 /*
2853 * If there are enough dots in the name, let's just give it a
2854 * try 'as is'. The threshold can be set with the "ndots" option.
2855 * Also, query 'as is', if there is a trailing dot in the name.
2856 */
2857 saved_herrno = -1;
2858 if (dots >= res->ndots || trailing_dot) {
2859 ret = res_querydomainN(name, NULL, target, res);
2860 if (ret > 0 || trailing_dot)
2861 return (ret);
2862 if (errno == ECONNREFUSED) {
2863 RES_SET_H_ERRNO(res, TRY_AGAIN);
2864 return (-1);
2865 }
2866 switch (res->res_h_errno) {
2867 case NO_DATA:
2868 case HOST_NOT_FOUND:
2869 break;
2870 case TRY_AGAIN:
2871 if (hp->rcode == SERVFAIL)
2872 break;
2873 /* FALLTHROUGH */
2874 default:
2875 return (-1);
2876 }
2877 saved_herrno = res->res_h_errno;
2878 tried_as_is++;
2879 }
2880
2881 /*
2882 * We do at least one level of search if
2883 * - there is no dot and RES_DEFNAME is set, or
2884 * - there is at least one dot, there is no trailing dot,
2885 * and RES_DNSRCH is set.
2886 */
2887 if ((!dots && (res->options & RES_DEFNAMES)) ||
2888 (dots && !trailing_dot && (res->options & RES_DNSRCH))) {
2889 int done = 0;
2890
2891 for (domain = (const char * const *)res->dnsrch;
2892 *domain && !done;
2893 domain++) {
2894 searched = 1;
2895
2896 if (domain[0][0] == '\0' ||
2897 (domain[0][0] == '.' && domain[0][1] == '\0'))
2898 root_on_list++;
2899
2900 if (root_on_list && tried_as_is)
2901 continue;
2902
2903 ret = res_querydomainN(name, *domain, target, res);
2904 if (ret > 0)
2905 return (ret);
2906
2907 /*
2908 * If no server present, give up.
2909 * If name isn't found in this domain,
2910 * keep trying higher domains in the search list
2911 * (if that's enabled).
2912 * On a NO_DATA error, keep trying, otherwise
2913 * a wildcard entry of another type could keep us
2914 * from finding this entry higher in the domain.
2915 * If we get some other error (negative answer or
2916 * server failure), then stop searching up,
2917 * but try the input name below in case it's
2918 * fully-qualified.
2919 */
2920 if (errno == ECONNREFUSED) {
2921 RES_SET_H_ERRNO(res, TRY_AGAIN);
2922 return (-1);
2923 }
2924
2925 switch (res->res_h_errno) {
2926 case NO_DATA:
2927 got_nodata++;
2928 /* FALLTHROUGH */
2929 case HOST_NOT_FOUND:
2930 /* keep trying */
2931 break;
2932 case TRY_AGAIN:
2933 got_servfail++;
2934 if (hp->rcode == SERVFAIL) {
2935 /* try next search element, if any */
2936 break;
2937 }
2938 /* FALLTHROUGH */
2939 default:
2940 /* anything else implies that we're done */
2941 done++;
2942 }
2943 /*
2944 * if we got here for some reason other than DNSRCH,
2945 * we only wanted one iteration of the loop, so stop.
2946 */
2947 if (!(res->options & RES_DNSRCH))
2948 done++;
2949 }
2950 }
2951
2952 switch (res->res_h_errno) {
2953 case NO_DATA:
2954 case HOST_NOT_FOUND:
2955 break;
2956 case TRY_AGAIN:
2957 if (hp->rcode == SERVFAIL)
2958 break;
2959 /* FALLTHROUGH */
2960 default:
2961 goto giveup;
2962 }
2963
2964 /*
2965 * If the query has not already been tried as is then try it
2966 * unless RES_NOTLDQUERY is set and there were no dots.
2967 */
2968 if ((dots || !searched || !(res->options & RES_NOTLDQUERY)) &&
2969 !(tried_as_is || root_on_list)) {
2970 ret = res_querydomainN(name, NULL, target, res);
2971 if (ret > 0)
2972 return (ret);
2973 }
2974
2975 /*
2976 * if we got here, we didn't satisfy the search.
2977 * if we did an initial full query, return that query's h_errno
2978 * (note that we wouldn't be here if that query had succeeded).
2979 * else if we ever got a nodata, send that back as the reason.
2980 * else send back meaningless h_errno, that being the one from
2981 * the last DNSRCH we did.
2982 */
2983 giveup:
2984 if (saved_herrno != -1)
2985 RES_SET_H_ERRNO(res, saved_herrno);
2986 else if (got_nodata)
2987 RES_SET_H_ERRNO(res, NO_DATA);
2988 else if (got_servfail)
2989 RES_SET_H_ERRNO(res, TRY_AGAIN);
2990 return (-1);
2991 }
2992
2993 /*
2994 * Perform a call on res_query on the concatenation of name and domain,
2995 * removing a trailing dot from name if domain is NULL.
2996 */
2997 static int
res_querydomainN(const char * name,const char * domain,struct res_target * target,res_state res)2998 res_querydomainN(const char *name, const char *domain,
2999 struct res_target *target, res_state res)
3000 {
3001 char nbuf[MAXDNAME];
3002 const char *longname = nbuf;
3003 size_t n, d;
3004
3005 #ifdef DEBUG
3006 if (res->options & RES_DEBUG)
3007 printf(";; res_querydomain(%s, %s)\n",
3008 name, domain?domain:"<Nil>");
3009 #endif
3010 if (domain == NULL) {
3011 /*
3012 * Check for trailing '.';
3013 * copy without '.' if present.
3014 */
3015 n = strlen(name);
3016 if (n >= MAXDNAME) {
3017 RES_SET_H_ERRNO(res, NO_RECOVERY);
3018 return (-1);
3019 }
3020 if (n > 0 && name[--n] == '.') {
3021 strncpy(nbuf, name, n);
3022 nbuf[n] = '\0';
3023 } else
3024 longname = name;
3025 } else {
3026 n = strlen(name);
3027 d = strlen(domain);
3028 if (n + d + 1 >= MAXDNAME) {
3029 RES_SET_H_ERRNO(res, NO_RECOVERY);
3030 return (-1);
3031 }
3032 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
3033 }
3034 return (res_queryN(longname, target, res));
3035 }
3036