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 "namespace.h"
57 #include <sys/param.h>
58 #include <sys/socket.h>
59 #include <net/if.h>
60 #include <netinet/in.h>
61 #include <net/if_types.h>
62 #include <ifaddrs.h>
63 #include <sys/queue.h>
64 #ifdef INET6
65 #include <sys/sysctl.h>
66 #include <sys/ioctl.h>
67 #include <netinet6/in6_var.h>
68 #include <netinet6/nd6.h>
69 #endif
70 #include <arpa/inet.h>
71 #include <arpa/nameser.h>
72 #include <rpc/rpc.h>
73 #include <rpcsvc/yp_prot.h>
74 #include <rpcsvc/ypclnt.h>
75 #include <netdb.h>
76 #include <resolv.h>
77 #include <string.h>
78 #include <stdlib.h>
79 #include <stddef.h>
80 #include <ctype.h>
81 #include <unistd.h>
82 #include <stdio.h>
83 #include <errno.h>
84
85 #include "res_config.h"
86
87 #ifdef DEBUG
88 #include <syslog.h>
89 #endif
90
91 #include <stdarg.h>
92 #include <nsswitch.h>
93 #include "un-namespace.h"
94 #include "netdb_private.h"
95 #include "libc_private.h"
96 #ifdef NS_CACHING
97 #include "nscache.h"
98 #endif
99
100 #define ANY 0
101 #define YES 1
102 #define NO 0
103
104 static const char in_addrany[] = { 0, 0, 0, 0 };
105 static const char in_loopback[] = { 127, 0, 0, 1 };
106 #ifdef INET6
107 static const char in6_addrany[] = {
108 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
109 };
110 static const char in6_loopback[] = {
111 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
112 };
113 #endif
114
115 struct policyqueue {
116 TAILQ_ENTRY(policyqueue) pc_entry;
117 #ifdef INET6
118 struct in6_addrpolicy pc_policy;
119 #endif
120 };
121 TAILQ_HEAD(policyhead, policyqueue);
122
123 static const struct afd {
124 int a_af;
125 int a_addrlen;
126 socklen_t a_socklen;
127 int a_off;
128 const char *a_addrany;
129 const char *a_loopback;
130 int a_scoped;
131 } afdl [] = {
132 #ifdef INET6
133 #define N_INET6 0
134 {PF_INET6, sizeof(struct in6_addr),
135 sizeof(struct sockaddr_in6),
136 offsetof(struct sockaddr_in6, sin6_addr),
137 in6_addrany, in6_loopback, 1},
138 #define N_INET 1
139 #define N_LOCAL 2
140 #else
141 #define N_INET 0
142 #define N_LOCAL 1
143 #endif
144 {PF_INET, sizeof(struct in_addr),
145 sizeof(struct sockaddr_in),
146 offsetof(struct sockaddr_in, sin_addr),
147 in_addrany, in_loopback, 0},
148 #define sizeofmember(type, member) (sizeof(((type *)0)->member))
149 {PF_LOCAL, sizeofmember(struct sockaddr_un, sun_path),
150 sizeof(struct sockaddr_un),
151 offsetof(struct sockaddr_un, sun_path),
152 NULL, NULL, 0},
153 {0, 0, 0, 0, NULL, NULL, 0},
154 };
155
156 struct explore {
157 int e_af;
158 int e_socktype;
159 int e_protocol;
160 int e_wild;
161 #define AF_ANY 0x01
162 #define SOCKTYPE_ANY 0x02
163 #define PROTOCOL_ANY 0x04
164 #define WILD_AF(ex) ((ex)->e_wild & AF_ANY)
165 #define WILD_SOCKTYPE(ex) ((ex)->e_wild & SOCKTYPE_ANY)
166 #define WILD_PROTOCOL(ex) ((ex)->e_wild & PROTOCOL_ANY)
167 };
168
169 static const struct explore explore[] = {
170 #ifdef INET6
171 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP,
172 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
173 { PF_INET6, SOCK_STREAM, IPPROTO_TCP,
174 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
175 { PF_INET6, SOCK_STREAM, IPPROTO_SCTP,
176 AF_ANY | SOCKTYPE_ANY },
177 { PF_INET6, SOCK_SEQPACKET, IPPROTO_SCTP,
178 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
179 { PF_INET6, SOCK_DGRAM, IPPROTO_UDPLITE,
180 AF_ANY | SOCKTYPE_ANY },
181 { PF_INET6, SOCK_RAW, ANY,
182 AF_ANY | PROTOCOL_ANY },
183 #endif
184 { PF_INET, SOCK_DGRAM, IPPROTO_UDP,
185 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
186 { PF_INET, SOCK_STREAM, IPPROTO_TCP,
187 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
188 { PF_INET, SOCK_STREAM, IPPROTO_SCTP,
189 AF_ANY | SOCKTYPE_ANY },
190 { PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP,
191 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
192 { PF_INET, SOCK_DGRAM, IPPROTO_UDPLITE,
193 AF_ANY | SOCKTYPE_ANY },
194 { PF_INET, SOCK_RAW, ANY,
195 AF_ANY | PROTOCOL_ANY },
196 { PF_LOCAL, SOCK_DGRAM, ANY,
197 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
198 { PF_LOCAL, SOCK_STREAM, ANY,
199 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
200 { PF_LOCAL, SOCK_SEQPACKET, ANY,
201 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY },
202 { -1, 0, 0, 0 },
203 };
204
205 #ifdef INET6
206 #define PTON_MAX 16
207 #else
208 #define PTON_MAX 4
209 #endif
210
211 #define AIO_SRCFLAG_DEPRECATED 0x1
212
213 struct ai_order {
214 union {
215 struct sockaddr_storage aiou_ss;
216 struct sockaddr aiou_sa;
217 } aio_src_un;
218 #define aio_srcsa aio_src_un.aiou_sa
219 u_int32_t aio_srcflag;
220 int aio_srcscope;
221 int aio_dstscope;
222 struct policyqueue *aio_srcpolicy;
223 struct policyqueue *aio_dstpolicy;
224 struct addrinfo *aio_ai;
225 int aio_matchlen;
226 int aio_initial_sequence;
227 };
228
229 static const ns_src default_dns_files[] = {
230 { NSSRC_FILES, NS_SUCCESS },
231 { NSSRC_DNS, NS_SUCCESS },
232 { 0 }
233 };
234
235 struct res_target {
236 struct res_target *next;
237 const char *name; /* domain name */
238 int qclass, qtype; /* class and type of query */
239 u_char *answer; /* buffer to put answer */
240 int anslen; /* size of answer buffer */
241 int n; /* result length */
242 };
243
244 #define MAXPACKET (64*1024)
245
246 typedef union {
247 HEADER hdr;
248 u_char buf[MAXPACKET];
249 } querybuf;
250
251 static int str2number(const char *, int *);
252 static int explore_copy(const struct addrinfo *, const struct addrinfo *,
253 struct addrinfo **);
254 static int explore_null(const struct addrinfo *,
255 const char *, struct addrinfo **);
256 static int explore_numeric(const struct addrinfo *, const char *,
257 const char *, struct addrinfo **, const char *);
258 static int explore_numeric_scope(const struct addrinfo *, const char *,
259 const char *, struct addrinfo **);
260 static int get_canonname(const struct addrinfo *,
261 struct addrinfo *, const char *);
262 static struct addrinfo *get_ai(const struct addrinfo *,
263 const struct afd *, const char *);
264 static struct addrinfo *copy_ai(const struct addrinfo *);
265 static int get_portmatch(const struct addrinfo *, const char *);
266 static int get_port(struct addrinfo *, const char *, int);
267 static const struct afd *find_afd(int);
268 static int addrconfig(struct addrinfo *);
269 #ifdef INET6
270 static int is_ifdisabled(char *);
271 #endif
272 static void set_source(struct ai_order *, struct policyhead *);
273 static int comp_dst(const void *, const void *);
274 #ifdef INET6
275 static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *);
276 #endif
277 static int gai_addr2scopetype(struct sockaddr *);
278
279 static int explore_fqdn(const struct addrinfo *, const char *,
280 const char *, struct addrinfo **);
281
282 static int reorder(struct addrinfo *);
283 static int get_addrselectpolicy(struct policyhead *);
284 static void free_addrselectpolicy(struct policyhead *);
285 static struct policyqueue *match_addrselectpolicy(struct sockaddr *,
286 struct policyhead *);
287 static int matchlen(struct sockaddr *, struct sockaddr *);
288
289 static struct addrinfo *getanswer(const querybuf *, int, const char *, int,
290 const struct addrinfo *, res_state);
291 #if defined(RESOLVSORT)
292 static int addr4sort(struct addrinfo *, res_state);
293 #endif
294 static int _dns_getaddrinfo(void *, void *, va_list);
295 static void _sethtent(FILE **);
296 static void _endhtent(FILE **);
297 static struct addrinfo *_gethtent(FILE **, const char *,
298 const struct addrinfo *);
299 static int _files_getaddrinfo(void *, void *, va_list);
300 #ifdef YP
301 static struct addrinfo *_yphostent(char *, const struct addrinfo *);
302 static int _yp_getaddrinfo(void *, void *, va_list);
303 #endif
304 #ifdef NS_CACHING
305 static int addrinfo_id_func(char *, size_t *, va_list, void *);
306 static int addrinfo_marshal_func(char *, size_t *, void *, va_list, void *);
307 static int addrinfo_unmarshal_func(char *, size_t, void *, va_list, void *);
308 #endif
309
310 static int res_queryN(const char *, struct res_target *, res_state);
311 static int res_searchN(const char *, struct res_target *, res_state);
312 static int res_querydomainN(const char *, const char *,
313 struct res_target *, res_state);
314
315 /* XXX macros that make external reference is BAD. */
316
317 #define GET_AI(ai, afd, addr) \
318 do { \
319 /* external reference: pai, error, and label free */ \
320 (ai) = get_ai(pai, (afd), (addr)); \
321 if ((ai) == NULL) { \
322 error = EAI_MEMORY; \
323 goto free; \
324 } \
325 } while (/*CONSTCOND*/0)
326
327 #define GET_PORT(ai, serv) \
328 do { \
329 /* external reference: error and label free */ \
330 error = get_port((ai), (serv), 0); \
331 if (error != 0) \
332 goto free; \
333 } while (/*CONSTCOND*/0)
334
335 #define GET_CANONNAME(ai, str) \
336 do { \
337 /* external reference: pai, error and label free */ \
338 error = get_canonname(pai, (ai), (str)); \
339 if (error != 0) \
340 goto free; \
341 } while (/*CONSTCOND*/0)
342
343 #define ERR(err) \
344 do { \
345 /* external reference: error, and label bad */ \
346 error = (err); \
347 goto bad; \
348 /*NOTREACHED*/ \
349 } while (/*CONSTCOND*/0)
350
351 #define MATCH_FAMILY(x, y, w) \
352 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC)))
353 #define MATCH(x, y, w) \
354 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
355
356 void
freeaddrinfo(struct addrinfo * ai)357 freeaddrinfo(struct addrinfo *ai)
358 {
359 struct addrinfo *next;
360
361 while (ai != NULL) {
362 next = ai->ai_next;
363 free(ai->ai_canonname);
364 /* no need to free(ai->ai_addr) */
365 free(ai);
366 ai = next;
367 }
368 }
369
370 static int
str2number(const char * p,int * portp)371 str2number(const char *p, int *portp)
372 {
373 char *ep;
374 unsigned long v;
375
376 if (*p == '\0')
377 return -1;
378 ep = NULL;
379 errno = 0;
380 v = strtoul(p, &ep, 10);
381 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX) {
382 *portp = v;
383 return 0;
384 } else
385 return -1;
386 }
387
388 int
getaddrinfo(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res)389 getaddrinfo(const char *hostname, const char *servname,
390 const struct addrinfo *hints, struct addrinfo **res)
391 {
392 struct addrinfo sentinel;
393 struct addrinfo *cur;
394 int error = 0;
395 struct addrinfo ai, ai0, *afai;
396 struct addrinfo *pai;
397 const struct afd *afd;
398 const struct explore *ex;
399 struct addrinfo *afailist[nitems(afdl)];
400 struct addrinfo *afai_unspec;
401 int found;
402 int numeric = 0;
403
404 /* ensure we return NULL on errors */
405 *res = NULL;
406
407 memset(&ai, 0, sizeof(ai));
408
409 memset(afailist, 0, sizeof(afailist));
410 afai_unspec = NULL;
411
412 memset(&sentinel, 0, sizeof(sentinel));
413 cur = &sentinel;
414 pai = &ai;
415 pai->ai_flags = 0;
416 pai->ai_family = PF_UNSPEC;
417 pai->ai_socktype = ANY;
418 pai->ai_protocol = ANY;
419 pai->ai_addrlen = 0;
420 pai->ai_canonname = NULL;
421 pai->ai_addr = NULL;
422 pai->ai_next = NULL;
423
424 if (hostname == NULL && servname == NULL)
425 return EAI_NONAME;
426 if (hints) {
427 /* error check for hints */
428 if (hints->ai_addrlen || hints->ai_canonname ||
429 hints->ai_addr || hints->ai_next)
430 ERR(EAI_BADHINTS); /* xxx */
431 if (hints->ai_flags & ~AI_MASK)
432 ERR(EAI_BADFLAGS);
433 switch (hints->ai_family) {
434 case PF_UNSPEC:
435 case PF_LOCAL:
436 case PF_INET:
437 #ifdef INET6
438 case PF_INET6:
439 #endif
440 break;
441 default:
442 ERR(EAI_FAMILY);
443 }
444 memcpy(pai, hints, sizeof(*pai));
445
446 /*
447 * if both socktype/protocol are specified, check if they
448 * are meaningful combination.
449 */
450 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
451 for (ex = explore; ex->e_af >= 0; ex++) {
452 if (!MATCH_FAMILY(pai->ai_family, ex->e_af,
453 WILD_AF(ex)))
454 continue;
455 if (!MATCH(pai->ai_socktype, ex->e_socktype,
456 WILD_SOCKTYPE(ex)))
457 continue;
458 if (!MATCH(pai->ai_protocol, ex->e_protocol,
459 WILD_PROTOCOL(ex)))
460 continue;
461
462 /* matched */
463 break;
464 }
465
466 if (ex->e_af < 0)
467 ERR(EAI_BADHINTS);
468 }
469 }
470
471 /*
472 * RFC 3493: AI_ALL and AI_V4MAPPED are effective only against
473 * AF_INET6 query. They need to be ignored if specified in other
474 * occasions.
475 */
476 switch (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) {
477 case AI_V4MAPPED:
478 case AI_ALL | AI_V4MAPPED:
479 #ifdef INET6
480 if (pai->ai_family != AF_INET6)
481 pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
482 break;
483 #endif
484 case AI_ALL:
485 pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
486 break;
487 }
488
489 /*
490 * check for special cases. (1) numeric servname is disallowed if
491 * socktype/protocol are left unspecified. (2) servname is disallowed
492 * for raw and other inet{,6} sockets.
493 */
494 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
495 #ifdef PF_INET6
496 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
497 #endif
498 ) {
499 ai0 = *pai; /* backup *pai */
500
501 if (pai->ai_family == PF_UNSPEC) {
502 #ifdef PF_INET6
503 pai->ai_family = PF_INET6;
504 #else
505 pai->ai_family = PF_INET;
506 #endif
507 }
508 error = get_portmatch(pai, servname);
509 if (error)
510 goto bad;
511
512 *pai = ai0;
513 }
514
515 ai0 = *pai;
516
517 /*
518 * NULL hostname, or numeric hostname.
519 * If numeric representation of AF1 can be interpreted as FQDN
520 * representation of AF2, we need to think again about the code below.
521 */
522 found = 0;
523 for (afd = afdl; afd->a_af; afd++) {
524 *pai = ai0;
525
526 if (!MATCH_FAMILY(pai->ai_family, afd->a_af, 1))
527 continue;
528
529 if (pai->ai_family == PF_UNSPEC)
530 pai->ai_family = afd->a_af;
531
532 if (hostname == NULL) {
533 error = explore_null(pai, servname,
534 &afailist[afd - afdl]);
535
536 /*
537 * Errors from explore_null should be unexpected and
538 * be caught to avoid returning an incomplete result.
539 */
540 if (error != 0)
541 goto bad;
542 } else {
543 error = explore_numeric_scope(pai, hostname, servname,
544 &afailist[afd - afdl]);
545
546 /*
547 * explore_numeric_scope returns an error for address
548 * families that do not match that of hostname.
549 * Thus we should not catch the error at this moment.
550 */
551 }
552
553 if (!error && afailist[afd - afdl])
554 found++;
555 }
556 if (found) {
557 numeric = 1;
558 goto globcopy;
559 }
560
561 if (hostname == NULL)
562 ERR(EAI_NONAME); /* used to be EAI_NODATA */
563 if (pai->ai_flags & AI_NUMERICHOST)
564 ERR(EAI_NONAME);
565
566 if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(&ai0))
567 ERR(EAI_FAIL);
568
569 /*
570 * hostname as alphabetical name.
571 */
572 *pai = ai0;
573 error = explore_fqdn(pai, hostname, servname, &afai_unspec);
574
575 globcopy:
576 for (ex = explore; ex->e_af >= 0; ex++) {
577 *pai = ai0;
578
579 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
580 continue;
581 if (!MATCH(pai->ai_socktype, ex->e_socktype,
582 WILD_SOCKTYPE(ex)))
583 continue;
584 if (!MATCH(pai->ai_protocol, ex->e_protocol,
585 WILD_PROTOCOL(ex)))
586 continue;
587
588 if (pai->ai_family == PF_UNSPEC)
589 pai->ai_family = ex->e_af;
590 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
591 pai->ai_socktype = ex->e_socktype;
592 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
593 pai->ai_protocol = ex->e_protocol;
594
595 /*
596 * if the servname does not match socktype/protocol, ignore it.
597 */
598 if (get_portmatch(pai, servname) != 0)
599 continue;
600
601 if (afai_unspec)
602 afai = afai_unspec;
603 else {
604 if ((afd = find_afd(pai->ai_family)) == NULL)
605 continue;
606 /* XXX assumes that afd points inside afdl[] */
607 afai = afailist[afd - afdl];
608 }
609 if (!afai)
610 continue;
611
612 error = explore_copy(pai, afai, &cur->ai_next);
613 if (error != 0)
614 goto bad;
615
616 while (cur && cur->ai_next)
617 cur = cur->ai_next;
618 }
619
620 /*
621 * ensure we return either:
622 * - error == 0, non-NULL *res
623 * - error != 0, NULL *res
624 */
625 if (error == 0) {
626 if (sentinel.ai_next) {
627 /*
628 * If the returned entry is for an active connection,
629 * and the given name is not numeric, reorder the
630 * list, so that the application would try the list
631 * in the most efficient order. Since the head entry
632 * of the original list may contain ai_canonname and
633 * that entry may be moved elsewhere in the new list,
634 * we keep the pointer and will restore it in the new
635 * head entry. (Note that RFC3493 requires the head
636 * entry store it when requested by the caller).
637 */
638 if (hints == NULL || !(hints->ai_flags & AI_PASSIVE)) {
639 if (!numeric) {
640 char *canonname;
641
642 canonname =
643 sentinel.ai_next->ai_canonname;
644 sentinel.ai_next->ai_canonname = NULL;
645 (void)reorder(&sentinel);
646 if (sentinel.ai_next->ai_canonname ==
647 NULL) {
648 sentinel.ai_next->ai_canonname
649 = canonname;
650 } else if (canonname != NULL)
651 free(canonname);
652 }
653 }
654 *res = sentinel.ai_next;
655 } else
656 error = EAI_FAIL;
657 }
658
659 bad:
660 if (afai_unspec)
661 freeaddrinfo(afai_unspec);
662 for (afd = afdl; afd->a_af; afd++) {
663 if (afailist[afd - afdl])
664 freeaddrinfo(afailist[afd - afdl]);
665 }
666 if (!*res)
667 if (sentinel.ai_next)
668 freeaddrinfo(sentinel.ai_next);
669
670 return (error);
671 }
672
673 static int
reorder(struct addrinfo * sentinel)674 reorder(struct addrinfo *sentinel)
675 {
676 struct addrinfo *ai, **aip;
677 struct ai_order *aio;
678 int i, n;
679 struct policyhead policyhead;
680
681 /* count the number of addrinfo elements for sorting. */
682 for (n = 0, ai = sentinel->ai_next; ai != NULL; ai = ai->ai_next, n++)
683 ;
684
685 /*
686 * If the number is small enough, we can skip the reordering process.
687 */
688 if (n <= 1)
689 return(n);
690
691 /* allocate a temporary array for sort and initialization of it. */
692 if ((aio = calloc(n, sizeof(*aio))) == NULL)
693 return(n); /* give up reordering */
694
695 /* retrieve address selection policy from the kernel */
696 TAILQ_INIT(&policyhead);
697 if (!get_addrselectpolicy(&policyhead)) {
698 /* no policy is installed into kernel, we don't sort. */
699 free(aio);
700 return (n);
701 }
702
703 for (i = 0, ai = sentinel->ai_next; i < n; ai = ai->ai_next, i++) {
704 aio[i].aio_ai = ai;
705 aio[i].aio_dstscope = gai_addr2scopetype(ai->ai_addr);
706 aio[i].aio_dstpolicy = match_addrselectpolicy(ai->ai_addr,
707 &policyhead);
708 set_source(&aio[i], &policyhead);
709 aio[i].aio_initial_sequence = i;
710 }
711
712 /* perform sorting. */
713 qsort(aio, n, sizeof(*aio), comp_dst);
714
715 /* reorder the addrinfo chain. */
716 for (i = 0, aip = &sentinel->ai_next; i < n; i++) {
717 *aip = aio[i].aio_ai;
718 aip = &aio[i].aio_ai->ai_next;
719 }
720 *aip = NULL;
721
722 /* cleanup and return */
723 free(aio);
724 free_addrselectpolicy(&policyhead);
725 return(n);
726 }
727
728 static int
get_addrselectpolicy(struct policyhead * head)729 get_addrselectpolicy(struct policyhead *head)
730 {
731 #ifdef INET6
732 int mib[] = { CTL_NET, PF_INET6, IPPROTO_IPV6, IPV6CTL_ADDRCTLPOLICY };
733 size_t l;
734 char *buf;
735 struct in6_addrpolicy *pol, *ep;
736
737 if (sysctl(mib, nitems(mib), NULL, &l, NULL, 0) < 0)
738 return (0);
739 if (l == 0)
740 return (0);
741 if ((buf = malloc(l)) == NULL)
742 return (0);
743 if (sysctl(mib, nitems(mib), buf, &l, NULL, 0) < 0) {
744 free(buf);
745 return (0);
746 }
747
748 ep = (struct in6_addrpolicy *)(buf + l);
749 for (pol = (struct in6_addrpolicy *)buf; pol + 1 <= ep; pol++) {
750 struct policyqueue *new;
751
752 if ((new = malloc(sizeof(*new))) == NULL) {
753 free_addrselectpolicy(head); /* make the list empty */
754 break;
755 }
756 new->pc_policy = *pol;
757 TAILQ_INSERT_TAIL(head, new, pc_entry);
758 }
759
760 free(buf);
761 return (1);
762 #else
763 return (0);
764 #endif
765 }
766
767 static void
free_addrselectpolicy(struct policyhead * head)768 free_addrselectpolicy(struct policyhead *head)
769 {
770 struct policyqueue *ent, *nent;
771
772 for (ent = TAILQ_FIRST(head); ent; ent = nent) {
773 nent = TAILQ_NEXT(ent, pc_entry);
774 TAILQ_REMOVE(head, ent, pc_entry);
775 free(ent);
776 }
777 }
778
779 static struct policyqueue *
match_addrselectpolicy(struct sockaddr * addr,struct policyhead * head)780 match_addrselectpolicy(struct sockaddr *addr, struct policyhead *head)
781 {
782 #ifdef INET6
783 struct policyqueue *ent, *bestent = NULL;
784 struct in6_addrpolicy *pol;
785 int matchlen, bestmatchlen = -1;
786 u_char *mp, *ep, *k, *p, m;
787 struct sockaddr_in6 key;
788
789 switch(addr->sa_family) {
790 case AF_INET6:
791 key = *(struct sockaddr_in6 *)addr;
792 break;
793 case AF_INET:
794 /* convert the address into IPv4-mapped IPv6 address. */
795 memset(&key, 0, sizeof(key));
796 key.sin6_family = AF_INET6;
797 key.sin6_len = sizeof(key);
798 _map_v4v6_address(
799 (char *)&((struct sockaddr_in *)addr)->sin_addr,
800 (char *)&key.sin6_addr);
801 break;
802 default:
803 return(NULL);
804 }
805
806 for (ent = TAILQ_FIRST(head); ent; ent = TAILQ_NEXT(ent, pc_entry)) {
807 pol = &ent->pc_policy;
808 matchlen = 0;
809
810 mp = (u_char *)&pol->addrmask.sin6_addr;
811 ep = mp + 16; /* XXX: scope field? */
812 k = (u_char *)&key.sin6_addr;
813 p = (u_char *)&pol->addr.sin6_addr;
814 for (; mp < ep && *mp; mp++, k++, p++) {
815 m = *mp;
816 if ((*k & m) != *p)
817 goto next; /* not match */
818 if (m == 0xff) /* short cut for a typical case */
819 matchlen += 8;
820 else {
821 while (m >= 0x80) {
822 matchlen++;
823 m <<= 1;
824 }
825 }
826 }
827
828 /* matched. check if this is better than the current best. */
829 if (matchlen > bestmatchlen) {
830 bestent = ent;
831 bestmatchlen = matchlen;
832 }
833
834 next:
835 continue;
836 }
837
838 return(bestent);
839 #else
840 return(NULL);
841 #endif
842
843 }
844
845 static void
set_source(struct ai_order * aio,struct policyhead * ph)846 set_source(struct ai_order *aio, struct policyhead *ph)
847 {
848 struct addrinfo ai = *aio->aio_ai;
849 struct sockaddr_storage ss;
850 socklen_t srclen;
851 int s;
852
853 /* set unspec ("no source is available"), just in case */
854 aio->aio_srcsa.sa_family = AF_UNSPEC;
855 aio->aio_srcscope = -1;
856
857 switch(ai.ai_family) {
858 case AF_INET:
859 #ifdef INET6
860 case AF_INET6:
861 #endif
862 break;
863 default: /* ignore unsupported AFs explicitly */
864 return;
865 }
866
867 /* XXX: make a dummy addrinfo to call connect() */
868 ai.ai_socktype = SOCK_DGRAM;
869 ai.ai_protocol = IPPROTO_UDP; /* is UDP too specific? */
870 ai.ai_next = NULL;
871 memset(&ss, 0, sizeof(ss));
872 memcpy(&ss, ai.ai_addr, ai.ai_addrlen);
873 ai.ai_addr = (struct sockaddr *)&ss;
874 get_port(&ai, "1", 0);
875
876 /* open a socket to get the source address for the given dst */
877 if ((s = _socket(ai.ai_family, ai.ai_socktype | SOCK_CLOEXEC,
878 ai.ai_protocol)) < 0)
879 return; /* give up */
880 #ifdef INET6
881 if (ai.ai_family == AF_INET6) {
882 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ai.ai_addr;
883 int off = 0;
884
885 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
886 (void)_setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
887 (char *)&off, sizeof(off));
888 }
889 #endif
890 if (_connect(s, ai.ai_addr, ai.ai_addrlen) < 0)
891 goto cleanup;
892 srclen = ai.ai_addrlen;
893 if (_getsockname(s, &aio->aio_srcsa, &srclen) < 0) {
894 aio->aio_srcsa.sa_family = AF_UNSPEC;
895 goto cleanup;
896 }
897 aio->aio_srcscope = gai_addr2scopetype(&aio->aio_srcsa);
898 aio->aio_srcpolicy = match_addrselectpolicy(&aio->aio_srcsa, ph);
899 aio->aio_matchlen = matchlen(&aio->aio_srcsa, aio->aio_ai->ai_addr);
900 #ifdef INET6
901 if (ai.ai_family == AF_INET6) {
902 struct in6_ifreq ifr6;
903 u_int32_t flags6;
904
905 memset(&ifr6, 0, sizeof(ifr6));
906 memcpy(&ifr6.ifr_addr, ai.ai_addr, ai.ai_addrlen);
907 if (_ioctl(s, SIOCGIFAFLAG_IN6, &ifr6) == 0) {
908 flags6 = ifr6.ifr_ifru.ifru_flags6;
909 if ((flags6 & IN6_IFF_DEPRECATED))
910 aio->aio_srcflag |= AIO_SRCFLAG_DEPRECATED;
911 }
912 }
913 #endif
914
915 cleanup:
916 _close(s);
917 return;
918 }
919
920 static int
matchlen(struct sockaddr * src,struct sockaddr * dst)921 matchlen(struct sockaddr *src, struct sockaddr *dst)
922 {
923 int match = 0;
924 u_char *s, *d;
925 u_char *lim, r;
926 int addrlen;
927
928 switch (src->sa_family) {
929 #ifdef INET6
930 case AF_INET6:
931 s = (u_char *)&((struct sockaddr_in6 *)src)->sin6_addr;
932 d = (u_char *)&((struct sockaddr_in6 *)dst)->sin6_addr;
933 addrlen = sizeof(struct in6_addr);
934 lim = s + addrlen;
935 break;
936 #endif
937 case AF_INET:
938 s = (u_char *)&((struct sockaddr_in *)src)->sin_addr;
939 d = (u_char *)&((struct sockaddr_in *)dst)->sin_addr;
940 addrlen = sizeof(struct in_addr);
941 lim = s + addrlen;
942 break;
943 default:
944 return(0);
945 }
946
947 while (s < lim)
948 if ((r = (*d++ ^ *s++)) != 0) {
949 while ((r & 0x80) == 0) {
950 match++;
951 r <<= 1;
952 }
953 break;
954 } else
955 match += 8;
956 return(match);
957 }
958
959 static int
comp_dst(const void * arg1,const void * arg2)960 comp_dst(const void *arg1, const void *arg2)
961 {
962 const struct ai_order *dst1 = arg1, *dst2 = arg2;
963
964 /*
965 * Rule 1: Avoid unusable destinations.
966 * XXX: we currently do not consider if an appropriate route exists.
967 */
968 if (dst1->aio_srcsa.sa_family != AF_UNSPEC &&
969 dst2->aio_srcsa.sa_family == AF_UNSPEC) {
970 return(-1);
971 }
972 if (dst1->aio_srcsa.sa_family == AF_UNSPEC &&
973 dst2->aio_srcsa.sa_family != AF_UNSPEC) {
974 return(1);
975 }
976
977 /* Rule 2: Prefer matching scope. */
978 if (dst1->aio_dstscope == dst1->aio_srcscope &&
979 dst2->aio_dstscope != dst2->aio_srcscope) {
980 return(-1);
981 }
982 if (dst1->aio_dstscope != dst1->aio_srcscope &&
983 dst2->aio_dstscope == dst2->aio_srcscope) {
984 return(1);
985 }
986
987 /* Rule 3: Avoid deprecated addresses. */
988 if (dst1->aio_srcsa.sa_family != AF_UNSPEC &&
989 dst2->aio_srcsa.sa_family != AF_UNSPEC) {
990 if (!(dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) &&
991 (dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) {
992 return(-1);
993 }
994 if ((dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) &&
995 !(dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) {
996 return(1);
997 }
998 }
999
1000 /* Rule 4: Prefer home addresses. */
1001 /* XXX: not implemented yet */
1002
1003 /* Rule 5: Prefer matching label. */
1004 #ifdef INET6
1005 if (dst1->aio_srcpolicy && dst1->aio_dstpolicy &&
1006 dst1->aio_srcpolicy->pc_policy.label ==
1007 dst1->aio_dstpolicy->pc_policy.label &&
1008 (dst2->aio_srcpolicy == NULL || dst2->aio_dstpolicy == NULL ||
1009 dst2->aio_srcpolicy->pc_policy.label !=
1010 dst2->aio_dstpolicy->pc_policy.label)) {
1011 return(-1);
1012 }
1013 if (dst2->aio_srcpolicy && dst2->aio_dstpolicy &&
1014 dst2->aio_srcpolicy->pc_policy.label ==
1015 dst2->aio_dstpolicy->pc_policy.label &&
1016 (dst1->aio_srcpolicy == NULL || dst1->aio_dstpolicy == NULL ||
1017 dst1->aio_srcpolicy->pc_policy.label !=
1018 dst1->aio_dstpolicy->pc_policy.label)) {
1019 return(1);
1020 }
1021 #endif
1022
1023 /* Rule 6: Prefer higher precedence. */
1024 #ifdef INET6
1025 if (dst1->aio_dstpolicy &&
1026 (dst2->aio_dstpolicy == NULL ||
1027 dst1->aio_dstpolicy->pc_policy.preced >
1028 dst2->aio_dstpolicy->pc_policy.preced)) {
1029 return(-1);
1030 }
1031 if (dst2->aio_dstpolicy &&
1032 (dst1->aio_dstpolicy == NULL ||
1033 dst2->aio_dstpolicy->pc_policy.preced >
1034 dst1->aio_dstpolicy->pc_policy.preced)) {
1035 return(1);
1036 }
1037 #endif
1038
1039 /* Rule 7: Prefer native transport. */
1040 /* XXX: not implemented yet */
1041
1042 /* Rule 8: Prefer smaller scope. */
1043 if (dst1->aio_dstscope >= 0 &&
1044 dst1->aio_dstscope < dst2->aio_dstscope) {
1045 return(-1);
1046 }
1047 if (dst2->aio_dstscope >= 0 &&
1048 dst2->aio_dstscope < dst1->aio_dstscope) {
1049 return(1);
1050 }
1051
1052 /*
1053 * Rule 9: Use longest matching prefix.
1054 * We compare the match length in a same AF only.
1055 */
1056 if (dst1->aio_ai->ai_addr->sa_family ==
1057 dst2->aio_ai->ai_addr->sa_family &&
1058 dst1->aio_ai->ai_addr->sa_family != AF_INET) {
1059 if (dst1->aio_matchlen > dst2->aio_matchlen) {
1060 return(-1);
1061 }
1062 if (dst1->aio_matchlen < dst2->aio_matchlen) {
1063 return(1);
1064 }
1065 }
1066
1067 /* Rule 10: Otherwise, leave the order unchanged. */
1068
1069 /*
1070 * Note that qsort is unstable; so, we can't return zero and
1071 * expect the order to be unchanged.
1072 * That also means we can't depend on the current position of
1073 * dst2 being after dst1. We must enforce the initial order
1074 * with an explicit compare on the original position.
1075 * The qsort specification requires that "When the same objects
1076 * (consisting of width bytes, irrespective of their current
1077 * positions in the array) are passed more than once to the
1078 * comparison function, the results shall be consistent with one
1079 * another."
1080 * In other words, If A < B, then we must also return B > A.
1081 */
1082 if (dst2->aio_initial_sequence < dst1->aio_initial_sequence)
1083 return(1);
1084
1085 return(-1);
1086 }
1087
1088 /*
1089 * Copy from scope.c.
1090 * XXX: we should standardize the functions and link them as standard
1091 * library.
1092 */
1093 static int
gai_addr2scopetype(struct sockaddr * sa)1094 gai_addr2scopetype(struct sockaddr *sa)
1095 {
1096 #ifdef INET6
1097 struct sockaddr_in6 *sa6;
1098 #endif
1099 struct sockaddr_in *sa4;
1100
1101 switch(sa->sa_family) {
1102 #ifdef INET6
1103 case AF_INET6:
1104 sa6 = (struct sockaddr_in6 *)sa;
1105 if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
1106 /* just use the scope field of the multicast address */
1107 return(sa6->sin6_addr.s6_addr[2] & 0x0f);
1108 }
1109 /*
1110 * Unicast addresses: map scope type to corresponding scope
1111 * value defined for multcast addresses.
1112 * XXX: hardcoded scope type values are bad...
1113 */
1114 if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr))
1115 return(1); /* node local scope */
1116 if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr))
1117 return(2); /* link-local scope */
1118 if (IN6_IS_ADDR_SITELOCAL(&sa6->sin6_addr))
1119 return(5); /* site-local scope */
1120 return(14); /* global scope */
1121 break;
1122 #endif
1123 case AF_INET:
1124 /*
1125 * IPv4 pseudo scoping according to RFC 3484.
1126 */
1127 sa4 = (struct sockaddr_in *)sa;
1128 /* IPv4 autoconfiguration addresses have link-local scope. */
1129 if (((u_char *)&sa4->sin_addr)[0] == 169 &&
1130 ((u_char *)&sa4->sin_addr)[1] == 254)
1131 return(2);
1132 /* Private addresses have site-local scope. */
1133 if (((u_char *)&sa4->sin_addr)[0] == 10 ||
1134 (((u_char *)&sa4->sin_addr)[0] == 172 &&
1135 (((u_char *)&sa4->sin_addr)[1] & 0xf0) == 16) ||
1136 (((u_char *)&sa4->sin_addr)[0] == 192 &&
1137 ((u_char *)&sa4->sin_addr)[1] == 168))
1138 return(14); /* XXX: It should be 5 unless NAT */
1139 /* Loopback addresses have link-local scope. */
1140 if (((u_char *)&sa4->sin_addr)[0] == 127)
1141 return(2);
1142 return(14);
1143 break;
1144 default:
1145 errno = EAFNOSUPPORT; /* is this a good error? */
1146 return(-1);
1147 }
1148 }
1149
1150 static int
explore_copy(const struct addrinfo * pai,const struct addrinfo * src0,struct addrinfo ** res)1151 explore_copy(const struct addrinfo *pai, const struct addrinfo *src0,
1152 struct addrinfo **res)
1153 {
1154 int error;
1155 struct addrinfo sentinel, *cur;
1156 const struct addrinfo *src;
1157
1158 error = 0;
1159 sentinel.ai_next = NULL;
1160 cur = &sentinel;
1161
1162 for (src = src0; src != NULL; src = src->ai_next) {
1163 if (src->ai_family != pai->ai_family)
1164 continue;
1165
1166 cur->ai_next = copy_ai(src);
1167 if (!cur->ai_next) {
1168 error = EAI_MEMORY;
1169 goto fail;
1170 }
1171
1172 cur->ai_next->ai_socktype = pai->ai_socktype;
1173 cur->ai_next->ai_protocol = pai->ai_protocol;
1174 cur = cur->ai_next;
1175 }
1176
1177 *res = sentinel.ai_next;
1178 return 0;
1179
1180 fail:
1181 freeaddrinfo(sentinel.ai_next);
1182 return error;
1183 }
1184
1185 /*
1186 * hostname == NULL.
1187 * passive socket -> anyaddr (0.0.0.0 or ::)
1188 * non-passive socket -> localhost (127.0.0.1 or ::1)
1189 */
1190 static int
explore_null(const struct addrinfo * pai,const char * servname,struct addrinfo ** res)1191 explore_null(const struct addrinfo *pai, const char *servname,
1192 struct addrinfo **res)
1193 {
1194 int s;
1195 const struct afd *afd;
1196 struct addrinfo *ai;
1197 int error;
1198
1199 *res = NULL;
1200 ai = NULL;
1201
1202 if (pai->ai_family == PF_LOCAL)
1203 return (0);
1204
1205 /*
1206 * filter out AFs that are not supported by the kernel
1207 * XXX errno?
1208 */
1209 s = _socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
1210 if (s < 0) {
1211 if (errno != EMFILE)
1212 return 0;
1213 } else
1214 _close(s);
1215
1216 afd = find_afd(pai->ai_family);
1217 if (afd == NULL)
1218 return 0;
1219
1220 if (pai->ai_flags & AI_PASSIVE) {
1221 GET_AI(ai, afd, afd->a_addrany);
1222 GET_PORT(ai, servname);
1223 } else {
1224 GET_AI(ai, afd, afd->a_loopback);
1225 GET_PORT(ai, servname);
1226 }
1227
1228 *res = ai;
1229 return 0;
1230
1231 free:
1232 if (ai != NULL)
1233 freeaddrinfo(ai);
1234 return error;
1235 }
1236
1237 /*
1238 * numeric hostname
1239 */
1240 static int
explore_numeric(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,const char * canonname)1241 explore_numeric(const struct addrinfo *pai, const char *hostname,
1242 const char *servname, struct addrinfo **res, const char *canonname)
1243 {
1244 const struct afd *afd;
1245 struct addrinfo *ai, ai0;
1246 int error;
1247 char pton[PTON_MAX], path[PATH_MAX], *p;
1248
1249 #ifdef CTASSERT
1250 CTASSERT(sizeofmember(struct sockaddr_un, sun_path) <= PATH_MAX);
1251 #endif
1252 *res = NULL;
1253 ai = NULL;
1254
1255 afd = find_afd(pai->ai_family);
1256 if (afd == NULL)
1257 return 0;
1258
1259 switch (afd->a_af) {
1260 case AF_LOCAL:
1261 if (hostname[0] != '/')
1262 ERR(EAI_NONAME);
1263 if (strlen(hostname) > afd->a_addrlen)
1264 ERR(EAI_MEMORY);
1265 /* NUL-termination does not need to be guaranteed. */
1266 strncpy(path, hostname, afd->a_addrlen);
1267 p = &path[0];
1268 break;
1269 case AF_INET:
1270 /*
1271 * RFC3493 requires getaddrinfo() to accept AF_INET formats
1272 * that are accepted by inet_addr() and its family. The
1273 * accepted forms includes the "classful" one, which inet_pton
1274 * does not accept. So we need to separate the case for
1275 * AF_INET.
1276 */
1277 if (inet_aton(hostname, (struct in_addr *)pton) != 1 ||
1278 hostname[strspn(hostname, "0123456789.xabcdefXABCDEF")] != '\0')
1279 return 0;
1280 p = pton;
1281 break;
1282 default:
1283 if (inet_pton(afd->a_af, hostname, pton) != 1) {
1284 if (pai->ai_family != AF_INET6 ||
1285 (pai->ai_flags & AI_V4MAPPED) != AI_V4MAPPED)
1286 return 0;
1287 if (inet_aton(hostname, (struct in_addr *)pton) != 1)
1288 return 0;
1289 afd = &afdl[N_INET];
1290 ai0 = *pai;
1291 ai0.ai_family = AF_INET;
1292 pai = &ai0;
1293 }
1294 p = pton;
1295 break;
1296 }
1297
1298 if (pai->ai_family == afd->a_af) {
1299 GET_AI(ai, afd, p);
1300 GET_PORT(ai, servname);
1301 if ((pai->ai_family == AF_INET ||
1302 pai->ai_family == AF_INET6) &&
1303 (pai->ai_flags & AI_CANONNAME)) {
1304 /*
1305 * Set the numeric address itself as the canonical
1306 * name, based on a clarification in RFC3493.
1307 */
1308 GET_CANONNAME(ai, canonname);
1309 }
1310 } else {
1311 /*
1312 * XXX: This should not happen since we already matched the AF
1313 * by find_afd.
1314 */
1315 ERR(EAI_FAMILY);
1316 }
1317
1318 *res = ai;
1319 return 0;
1320
1321 free:
1322 bad:
1323 if (ai != NULL)
1324 freeaddrinfo(ai);
1325 return error;
1326 }
1327
1328 /*
1329 * numeric hostname with scope
1330 */
1331 static int
explore_numeric_scope(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res)1332 explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
1333 const char *servname, struct addrinfo **res)
1334 {
1335 #if !defined(SCOPE_DELIMITER) || !defined(INET6)
1336 return explore_numeric(pai, hostname, servname, res, hostname);
1337 #else
1338 const struct afd *afd;
1339 struct addrinfo *cur;
1340 int error;
1341 char *cp, *hostname2 = NULL, *scope, *addr;
1342 struct sockaddr_in6 *sin6;
1343
1344 afd = find_afd(pai->ai_family);
1345 if (afd == NULL)
1346 return 0;
1347
1348 if (!afd->a_scoped)
1349 return explore_numeric(pai, hostname, servname, res, hostname);
1350
1351 cp = strchr(hostname, SCOPE_DELIMITER);
1352 if (cp == NULL)
1353 return explore_numeric(pai, hostname, servname, res, hostname);
1354
1355 /*
1356 * Handle special case of <scoped_address><delimiter><scope id>
1357 */
1358 hostname2 = strdup(hostname);
1359 if (hostname2 == NULL)
1360 return EAI_MEMORY;
1361 /* terminate at the delimiter */
1362 hostname2[cp - hostname] = '\0';
1363 addr = hostname2;
1364 scope = cp + 1;
1365
1366 error = explore_numeric(pai, addr, servname, res, hostname);
1367 if (error == 0) {
1368 u_int32_t scopeid;
1369
1370 for (cur = *res; cur; cur = cur->ai_next) {
1371 if (cur->ai_family != AF_INET6)
1372 continue;
1373 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
1374 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
1375 free(hostname2);
1376 freeaddrinfo(*res);
1377 *res = NULL;
1378 return(EAI_NONAME); /* XXX: is return OK? */
1379 }
1380 sin6->sin6_scope_id = scopeid;
1381 }
1382 }
1383
1384 free(hostname2);
1385
1386 if (error && *res) {
1387 freeaddrinfo(*res);
1388 *res = NULL;
1389 }
1390 return error;
1391 #endif
1392 }
1393
1394 static int
get_canonname(const struct addrinfo * pai,struct addrinfo * ai,const char * str)1395 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
1396 {
1397 if ((pai->ai_flags & AI_CANONNAME) != 0) {
1398 ai->ai_canonname = strdup(str);
1399 if (ai->ai_canonname == NULL)
1400 return EAI_MEMORY;
1401 }
1402 return 0;
1403 }
1404
1405 static struct addrinfo *
get_ai(const struct addrinfo * pai,const struct afd * afd,const char * addr)1406 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
1407 {
1408 char *p;
1409 struct addrinfo *ai;
1410 #ifdef INET6
1411 struct in6_addr mapaddr;
1412
1413 if (afd->a_af == AF_INET && (pai->ai_flags & AI_V4MAPPED) != 0) {
1414 afd = &afdl[N_INET6];
1415 _map_v4v6_address(addr, (char *)&mapaddr);
1416 addr = (char *)&mapaddr;
1417 }
1418 #endif
1419
1420 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
1421 + (afd->a_socklen));
1422 if (ai == NULL)
1423 return NULL;
1424
1425 memcpy(ai, pai, sizeof(struct addrinfo));
1426 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1427 memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1428 ai->ai_addr->sa_len = afd->a_socklen;
1429 ai->ai_addrlen = afd->a_socklen;
1430 if (ai->ai_family == PF_LOCAL) {
1431 size_t n = strnlen(addr, afd->a_addrlen);
1432
1433 ai->ai_addrlen -= afd->a_addrlen - n;
1434 ai->ai_addr->sa_len -= afd->a_addrlen - n;
1435 }
1436 ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1437 p = (char *)(void *)(ai->ai_addr);
1438 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
1439 return ai;
1440 }
1441
1442 /* XXX need to malloc() the same way we do from other functions! */
1443 static struct addrinfo *
copy_ai(const struct addrinfo * pai)1444 copy_ai(const struct addrinfo *pai)
1445 {
1446 struct addrinfo *ai;
1447 size_t l;
1448
1449 l = sizeof(*ai) + pai->ai_addrlen;
1450 if ((ai = calloc(1, l)) == NULL)
1451 return NULL;
1452 memcpy(ai, pai, sizeof(*ai));
1453 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1454 memcpy(ai->ai_addr, pai->ai_addr, pai->ai_addrlen);
1455
1456 if (pai->ai_canonname) {
1457 l = strlen(pai->ai_canonname) + 1;
1458 if ((ai->ai_canonname = malloc(l)) == NULL) {
1459 free(ai);
1460 return NULL;
1461 }
1462 strlcpy(ai->ai_canonname, pai->ai_canonname, l);
1463 } else {
1464 /* just to make sure */
1465 ai->ai_canonname = NULL;
1466 }
1467
1468 ai->ai_next = NULL;
1469
1470 return ai;
1471 }
1472
1473 static int
get_portmatch(const struct addrinfo * ai,const char * servname)1474 get_portmatch(const struct addrinfo *ai, const char *servname)
1475 {
1476
1477 /* get_port does not touch first argument when matchonly == 1. */
1478 /* LINTED const cast */
1479 return get_port((struct addrinfo *)ai, servname, 1);
1480 }
1481
1482 static int
get_port(struct addrinfo * ai,const char * servname,int matchonly)1483 get_port(struct addrinfo *ai, const char *servname, int matchonly)
1484 {
1485 const char *proto;
1486 struct servent *sp;
1487 int port, error;
1488 int allownumeric;
1489
1490 if (servname == NULL)
1491 return 0;
1492 switch (ai->ai_family) {
1493 case AF_LOCAL:
1494 /* AF_LOCAL ignores servname silently. */
1495 return (0);
1496 case AF_INET:
1497 #ifdef AF_INET6
1498 case AF_INET6:
1499 #endif
1500 break;
1501 default:
1502 return 0;
1503 }
1504
1505 switch (ai->ai_socktype) {
1506 case SOCK_RAW:
1507 return EAI_SERVICE;
1508 case SOCK_DGRAM:
1509 case SOCK_STREAM:
1510 case SOCK_SEQPACKET:
1511 allownumeric = 1;
1512 break;
1513 case ANY:
1514 switch (ai->ai_family) {
1515 case AF_INET:
1516 #ifdef AF_INET6
1517 case AF_INET6:
1518 #endif
1519 allownumeric = 1;
1520 break;
1521 default:
1522 allownumeric = 0;
1523 break;
1524 }
1525 break;
1526 default:
1527 return EAI_SOCKTYPE;
1528 }
1529
1530 error = str2number(servname, &port);
1531 if (error == 0) {
1532 if (!allownumeric)
1533 return EAI_SERVICE;
1534 if (port < 0 || port > 65535)
1535 return EAI_SERVICE;
1536 port = htons(port);
1537 } else {
1538 if (ai->ai_flags & AI_NUMERICSERV)
1539 return EAI_NONAME;
1540
1541 switch (ai->ai_protocol) {
1542 case IPPROTO_UDP:
1543 proto = "udp";
1544 break;
1545 case IPPROTO_TCP:
1546 proto = "tcp";
1547 break;
1548 case IPPROTO_SCTP:
1549 proto = "sctp";
1550 break;
1551 case IPPROTO_UDPLITE:
1552 proto = "udplite";
1553 break;
1554 default:
1555 proto = NULL;
1556 break;
1557 }
1558
1559 if ((sp = getservbyname(servname, proto)) == NULL)
1560 return EAI_SERVICE;
1561 port = sp->s_port;
1562 }
1563
1564 if (!matchonly) {
1565 switch (ai->ai_family) {
1566 case AF_INET:
1567 ((struct sockaddr_in *)(void *)
1568 ai->ai_addr)->sin_port = port;
1569 break;
1570 #ifdef INET6
1571 case AF_INET6:
1572 ((struct sockaddr_in6 *)(void *)
1573 ai->ai_addr)->sin6_port = port;
1574 break;
1575 #endif
1576 }
1577 }
1578
1579 return 0;
1580 }
1581
1582 static const struct afd *
find_afd(int af)1583 find_afd(int af)
1584 {
1585 const struct afd *afd;
1586
1587 if (af == PF_UNSPEC)
1588 return NULL;
1589 for (afd = afdl; afd->a_af; afd++) {
1590 if (afd->a_af == af)
1591 return afd;
1592 }
1593 return NULL;
1594 }
1595
1596 /*
1597 * RFC 3493: AI_ADDRCONFIG check. Determines which address families are
1598 * configured on the local system and correlates with pai->ai_family value.
1599 * If an address family is not configured on the system, it will not be
1600 * queried for. For this purpose, loopback addresses are not considered
1601 * configured addresses.
1602 *
1603 * XXX PF_UNSPEC -> PF_INET6 + PF_INET mapping needs to be in sync with
1604 * _dns_getaddrinfo.
1605 */
1606 static int
addrconfig(struct addrinfo * pai)1607 addrconfig(struct addrinfo *pai)
1608 {
1609 struct ifaddrs *ifaddrs, *ifa;
1610 struct sockaddr_in *sin;
1611 #ifdef INET6
1612 struct sockaddr_in6 *sin6;
1613 #endif
1614 int seen_inet = 0, seen_inet6 = 0;
1615
1616 if (getifaddrs(&ifaddrs) != 0)
1617 return (0);
1618
1619 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
1620 if (ifa->ifa_addr == NULL || (ifa->ifa_flags & IFF_UP) == 0)
1621 continue;
1622 switch (ifa->ifa_addr->sa_family) {
1623 case AF_INET:
1624 if (seen_inet)
1625 continue;
1626 sin = (struct sockaddr_in *)(ifa->ifa_addr);
1627 if (htonl(sin->sin_addr.s_addr) == INADDR_LOOPBACK)
1628 continue;
1629 seen_inet = 1;
1630 break;
1631 #ifdef INET6
1632 case AF_INET6:
1633 if (seen_inet6)
1634 continue;
1635 sin6 = (struct sockaddr_in6 *)(ifa->ifa_addr);
1636 if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
1637 continue;
1638 if ((ifa->ifa_flags & IFT_LOOP) != 0 &&
1639 IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
1640 continue;
1641 if (is_ifdisabled(ifa->ifa_name))
1642 continue;
1643 seen_inet6 = 1;
1644 break;
1645 #endif
1646 }
1647 }
1648 freeifaddrs(ifaddrs);
1649
1650 switch(pai->ai_family) {
1651 case AF_INET6:
1652 return (seen_inet6);
1653 case AF_INET:
1654 return (seen_inet);
1655 case AF_UNSPEC:
1656 if (seen_inet == seen_inet6)
1657 return (seen_inet);
1658 pai->ai_family = seen_inet ? AF_INET : AF_INET6;
1659 return (1);
1660 }
1661 return (1);
1662 }
1663
1664 #ifdef INET6
1665 static int
is_ifdisabled(char * name)1666 is_ifdisabled(char *name)
1667 {
1668 struct in6_ndireq nd;
1669 int fd;
1670
1671 if ((fd = _socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0)) < 0)
1672 return (-1);
1673 memset(&nd, 0, sizeof(nd));
1674 strlcpy(nd.ifname, name, sizeof(nd.ifname));
1675 if (_ioctl(fd, SIOCGIFINFO_IN6, &nd) < 0) {
1676 _close(fd);
1677 return (-1);
1678 }
1679 _close(fd);
1680 return ((nd.ndi.flags & ND6_IFF_IFDISABLED) != 0);
1681 }
1682
1683 /* convert a string to a scope identifier. XXX: IPv6 specific */
1684 static int
ip6_str2scopeid(char * scope,struct sockaddr_in6 * sin6,u_int32_t * scopeid)1685 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
1686 {
1687 u_long lscopeid;
1688 struct in6_addr *a6;
1689 char *ep;
1690
1691 a6 = &sin6->sin6_addr;
1692
1693 /* empty scopeid portion is invalid */
1694 if (*scope == '\0')
1695 return -1;
1696
1697 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) ||
1698 IN6_IS_ADDR_MC_NODELOCAL(a6)) {
1699 /*
1700 * We currently assume a one-to-one mapping between links
1701 * and interfaces, so we simply use interface indices for
1702 * like-local scopes.
1703 */
1704 *scopeid = if_nametoindex(scope);
1705 if (*scopeid == 0)
1706 goto trynumeric;
1707 return 0;
1708 }
1709
1710 /* still unclear about literal, allow numeric only - placeholder */
1711 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1712 goto trynumeric;
1713 if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1714 goto trynumeric;
1715 else
1716 goto trynumeric; /* global */
1717
1718 /* try to convert to a numeric id as a last resort */
1719 trynumeric:
1720 errno = 0;
1721 lscopeid = strtoul(scope, &ep, 10);
1722 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
1723 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
1724 return 0;
1725 else
1726 return -1;
1727 }
1728 #endif
1729
1730
1731 #ifdef NS_CACHING
1732 static int
addrinfo_id_func(char * buffer,size_t * buffer_size,va_list ap,void * cache_mdata)1733 addrinfo_id_func(char *buffer, size_t *buffer_size, va_list ap,
1734 void *cache_mdata)
1735 {
1736 res_state statp;
1737 u_long res_options;
1738
1739 const int op_id = 0; /* identifies the getaddrinfo for the cache */
1740 char *hostname;
1741 struct addrinfo *hints;
1742
1743 char *p;
1744 int ai_flags, ai_family, ai_socktype, ai_protocol;
1745 size_t desired_size, size;
1746
1747 statp = __res_state();
1748 res_options = statp->options & (RES_RECURSE | RES_DEFNAMES |
1749 RES_DNSRCH | RES_NOALIASES | RES_USE_INET6);
1750
1751 hostname = va_arg(ap, char *);
1752 hints = va_arg(ap, struct addrinfo *);
1753
1754 desired_size = sizeof(res_options) + sizeof(int) + sizeof(int) * 4;
1755 if (hostname != NULL) {
1756 size = strlen(hostname);
1757 desired_size += size + 1;
1758 } else
1759 size = 0;
1760
1761 if (desired_size > *buffer_size) {
1762 *buffer_size = desired_size;
1763 return (NS_RETURN);
1764 }
1765
1766 if (hints == NULL)
1767 ai_flags = ai_family = ai_socktype = ai_protocol = 0;
1768 else {
1769 ai_flags = hints->ai_flags;
1770 ai_family = hints->ai_family;
1771 ai_socktype = hints->ai_socktype;
1772 ai_protocol = hints->ai_protocol;
1773 }
1774
1775 p = buffer;
1776 memcpy(p, &res_options, sizeof(res_options));
1777 p += sizeof(res_options);
1778
1779 memcpy(p, &op_id, sizeof(int));
1780 p += sizeof(int);
1781
1782 memcpy(p, &ai_flags, sizeof(int));
1783 p += sizeof(int);
1784
1785 memcpy(p, &ai_family, sizeof(int));
1786 p += sizeof(int);
1787
1788 memcpy(p, &ai_socktype, sizeof(int));
1789 p += sizeof(int);
1790
1791 memcpy(p, &ai_protocol, sizeof(int));
1792 p += sizeof(int);
1793
1794 if (hostname != NULL)
1795 memcpy(p, hostname, size);
1796
1797 *buffer_size = desired_size;
1798 return (NS_SUCCESS);
1799 }
1800
1801 static int
addrinfo_marshal_func(char * buffer,size_t * buffer_size,void * retval,va_list ap,void * cache_mdata)1802 addrinfo_marshal_func(char *buffer, size_t *buffer_size, void *retval,
1803 va_list ap, void *cache_mdata)
1804 {
1805 struct addrinfo *ai, *cai;
1806 char *p;
1807 size_t desired_size, size, ai_size;
1808
1809 ai = *((struct addrinfo **)retval);
1810
1811 desired_size = sizeof(size_t);
1812 ai_size = 0;
1813 for (cai = ai; cai != NULL; cai = cai->ai_next) {
1814 desired_size += sizeof(struct addrinfo) + cai->ai_addrlen;
1815 if (cai->ai_canonname != NULL)
1816 desired_size += sizeof(size_t) +
1817 strlen(cai->ai_canonname);
1818 ++ai_size;
1819 }
1820
1821 if (desired_size > *buffer_size) {
1822 /* this assignment is here for future use */
1823 errno = ERANGE;
1824 *buffer_size = desired_size;
1825 return (NS_RETURN);
1826 }
1827
1828 memset(buffer, 0, desired_size);
1829 p = buffer;
1830
1831 memcpy(p, &ai_size, sizeof(size_t));
1832 p += sizeof(size_t);
1833 for (cai = ai; cai != NULL; cai = cai->ai_next) {
1834 memcpy(p, cai, sizeof(struct addrinfo));
1835 p += sizeof(struct addrinfo);
1836
1837 memcpy(p, cai->ai_addr, cai->ai_addrlen);
1838 p += cai->ai_addrlen;
1839
1840 if (cai->ai_canonname != NULL) {
1841 size = strlen(cai->ai_canonname);
1842 memcpy(p, &size, sizeof(size_t));
1843 p += sizeof(size_t);
1844
1845 memcpy(p, cai->ai_canonname, size);
1846 p += size;
1847 }
1848 }
1849
1850 return (NS_SUCCESS);
1851 }
1852
1853 static int
addrinfo_unmarshal_func(char * buffer,size_t buffer_size,void * retval,va_list ap,void * cache_mdata)1854 addrinfo_unmarshal_func(char *buffer, size_t buffer_size, void *retval,
1855 va_list ap, void *cache_mdata)
1856 {
1857 struct addrinfo new_ai, *result, *sentinel, *lasts;
1858
1859 char *p;
1860 size_t ai_size, ai_i, size;
1861
1862 p = buffer;
1863 memcpy(&ai_size, p, sizeof(size_t));
1864 p += sizeof(size_t);
1865
1866 result = NULL;
1867 lasts = NULL;
1868 for (ai_i = 0; ai_i < ai_size; ++ai_i) {
1869 memcpy(&new_ai, p, sizeof(struct addrinfo));
1870 p += sizeof(struct addrinfo);
1871 size = new_ai.ai_addrlen + sizeof(struct addrinfo) +
1872 _ALIGNBYTES;
1873
1874 sentinel = calloc(1, size);
1875
1876 memcpy(sentinel, &new_ai, sizeof(struct addrinfo));
1877 sentinel->ai_addr = (struct sockaddr *)_ALIGN((char *)sentinel +
1878 sizeof(struct addrinfo));
1879
1880 memcpy(sentinel->ai_addr, p, new_ai.ai_addrlen);
1881 p += new_ai.ai_addrlen;
1882
1883 if (new_ai.ai_canonname != NULL) {
1884 memcpy(&size, p, sizeof(size_t));
1885 p += sizeof(size_t);
1886
1887 sentinel->ai_canonname = calloc(1, size + 1);
1888
1889 memcpy(sentinel->ai_canonname, p, size);
1890 p += size;
1891 }
1892
1893 if (result == NULL) {
1894 result = sentinel;
1895 lasts = sentinel;
1896 } else {
1897 lasts->ai_next = sentinel;
1898 lasts = sentinel;
1899 }
1900 }
1901
1902 *((struct addrinfo **)retval) = result;
1903 return (NS_SUCCESS);
1904 }
1905 #endif /* NS_CACHING */
1906
1907 /*
1908 * FQDN hostname, DNS lookup
1909 */
1910 static int
explore_fqdn(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res)1911 explore_fqdn(const struct addrinfo *pai, const char *hostname,
1912 const char *servname, struct addrinfo **res)
1913 {
1914 struct addrinfo *result;
1915 struct addrinfo *cur;
1916 int error = 0;
1917
1918 #ifdef NS_CACHING
1919 static const nss_cache_info cache_info =
1920 NS_COMMON_CACHE_INFO_INITIALIZER(
1921 hosts, NULL, addrinfo_id_func, addrinfo_marshal_func,
1922 addrinfo_unmarshal_func);
1923 #endif
1924 static const ns_dtab dtab[] = {
1925 NS_FILES_CB(_files_getaddrinfo, NULL)
1926 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
1927 NS_NIS_CB(_yp_getaddrinfo, NULL)
1928 #ifdef NS_CACHING
1929 NS_CACHE_CB(&cache_info)
1930 #endif
1931 { 0 }
1932 };
1933
1934 result = NULL;
1935
1936 /*
1937 * if the servname does not match socktype/protocol, ignore it.
1938 */
1939 if (get_portmatch(pai, servname) != 0)
1940 return 0;
1941
1942 switch (_nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
1943 default_dns_files, hostname, pai)) {
1944 case NS_TRYAGAIN:
1945 error = EAI_AGAIN;
1946 goto free;
1947 case NS_UNAVAIL:
1948 error = EAI_FAIL;
1949 goto free;
1950 case NS_NOTFOUND:
1951 error = EAI_NONAME;
1952 goto free;
1953 case NS_ADDRFAMILY:
1954 error = EAI_ADDRFAMILY;
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 != T_DNAME && type != T_RRSIG)
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 if (res->res_h_errno == NO_DATA)
2345 return (NS_ADDRFAMILY);
2346 return (NS_NOTFOUND);
2347 }
2348 /* prefer IPv6 */
2349 if (q.next) {
2350 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai, res);
2351 if (ai != NULL) {
2352 cur->ai_next = ai;
2353 while (cur && cur->ai_next)
2354 cur = cur->ai_next;
2355 }
2356 }
2357 if (ai == NULL || pai->ai_family != AF_UNSPEC ||
2358 (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) != AI_V4MAPPED) {
2359 ai = getanswer(buf, q.n, q.name, q.qtype, pai, res);
2360 if (ai != NULL)
2361 cur->ai_next = ai;
2362 }
2363 free(buf);
2364 free(buf2);
2365 if (sentinel.ai_next == NULL)
2366 switch (res->res_h_errno) {
2367 case HOST_NOT_FOUND:
2368 return (NS_NOTFOUND);
2369 case NO_DATA:
2370 return (NS_ADDRFAMILY);
2371 case TRY_AGAIN:
2372 return (NS_TRYAGAIN);
2373 default:
2374 return (NS_UNAVAIL);
2375 }
2376 *((struct addrinfo **)rv) = sentinel.ai_next;
2377 return (NS_SUCCESS);
2378 }
2379
2380 static void
_sethtent(FILE ** hostf)2381 _sethtent(FILE **hostf)
2382 {
2383 if (!*hostf)
2384 *hostf = fopen(_PATH_HOSTS, "re");
2385 else
2386 rewind(*hostf);
2387 }
2388
2389 static void
_endhtent(FILE ** hostf)2390 _endhtent(FILE **hostf)
2391 {
2392 if (*hostf) {
2393 (void) fclose(*hostf);
2394 *hostf = NULL;
2395 }
2396 }
2397
2398 static struct addrinfo *
_gethtent(FILE ** hostf,const char * name,const struct addrinfo * pai)2399 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai)
2400 {
2401 char *p;
2402 char *cp, *tname, *cname;
2403 struct addrinfo hints, *res0, *res;
2404 int error;
2405 const char *addr;
2406 char hostbuf[8*1024];
2407
2408 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re")))
2409 return (NULL);
2410 again:
2411 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf)))
2412 return (NULL);
2413 if (*p == '#')
2414 goto again;
2415 cp = strpbrk(p, "#\n");
2416 if (cp != NULL)
2417 *cp = '\0';
2418 if (!(cp = strpbrk(p, " \t")))
2419 goto again;
2420 *cp++ = '\0';
2421 addr = p;
2422 cname = NULL;
2423 /* if this is not something we're looking for, skip it. */
2424 while (cp && *cp) {
2425 if (*cp == ' ' || *cp == '\t') {
2426 cp++;
2427 continue;
2428 }
2429 tname = cp;
2430 if (cname == NULL)
2431 cname = cp;
2432 if ((cp = strpbrk(cp, " \t")) != NULL)
2433 *cp++ = '\0';
2434 if (strcasecmp(name, tname) == 0)
2435 goto found;
2436 }
2437 goto again;
2438
2439 found:
2440 /* we should not glob socktype/protocol here */
2441 memset(&hints, 0, sizeof(hints));
2442 hints.ai_family = pai->ai_family;
2443 hints.ai_socktype = SOCK_DGRAM;
2444 hints.ai_protocol = 0;
2445 hints.ai_flags = AI_NUMERICHOST;
2446 if (pai->ai_family == AF_INET6 &&
2447 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED)
2448 hints.ai_flags |= AI_V4MAPPED;
2449 error = getaddrinfo(addr, "0", &hints, &res0);
2450 if (error)
2451 goto again;
2452 #ifdef FILTER_V4MAPPED
2453 /* XXX should check all items in the chain */
2454 if (res0->ai_family == AF_INET6 &&
2455 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)res0->ai_addr)->sin6_addr)) {
2456 freeaddrinfo(res0);
2457 goto again;
2458 }
2459 #endif
2460 for (res = res0; res; res = res->ai_next) {
2461 /* cover it up */
2462 res->ai_flags = pai->ai_flags;
2463 res->ai_socktype = pai->ai_socktype;
2464 res->ai_protocol = pai->ai_protocol;
2465
2466 if (pai->ai_flags & AI_CANONNAME) {
2467 if (get_canonname(pai, res, cname) != 0) {
2468 freeaddrinfo(res0);
2469 goto again;
2470 }
2471 }
2472 }
2473 return res0;
2474 }
2475
2476 static struct addrinfo *
_getht(FILE ** hostf,const char * name,const struct addrinfo * pai,struct addrinfo * cur)2477 _getht(FILE **hostf, const char *name, const struct addrinfo *pai,
2478 struct addrinfo *cur)
2479 {
2480 struct addrinfo *p;
2481
2482 while ((p = _gethtent(hostf, name, pai)) != NULL) {
2483 cur->ai_next = p;
2484 while (cur && cur->ai_next)
2485 cur = cur->ai_next;
2486 }
2487 return (cur);
2488 }
2489
2490 /*ARGSUSED*/
2491 static int
_files_getaddrinfo(void * rv,void * cb_data,va_list ap)2492 _files_getaddrinfo(void *rv, void *cb_data, va_list ap)
2493 {
2494 const char *name;
2495 const struct addrinfo *pai;
2496 struct addrinfo sentinel, *cur;
2497 FILE *hostf = NULL;
2498
2499 name = va_arg(ap, char *);
2500 pai = va_arg(ap, struct addrinfo *);
2501
2502 memset(&sentinel, 0, sizeof(sentinel));
2503 cur = &sentinel;
2504
2505 _sethtent(&hostf);
2506 if (pai->ai_family == AF_INET6 &&
2507 (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) == AI_V4MAPPED) {
2508 struct addrinfo ai0 = *pai;
2509
2510 ai0.ai_flags &= ~AI_V4MAPPED;
2511 cur = _getht(&hostf, name, &ai0, cur);
2512 if (sentinel.ai_next == NULL) {
2513 _sethtent(&hostf);
2514 ai0.ai_flags |= AI_V4MAPPED;
2515 cur = _getht(&hostf, name, &ai0, cur);
2516 }
2517 } else
2518 cur = _getht(&hostf, name, pai, cur);
2519 _endhtent(&hostf);
2520
2521 *((struct addrinfo **)rv) = sentinel.ai_next;
2522 if (sentinel.ai_next == NULL)
2523 return NS_NOTFOUND;
2524 return NS_SUCCESS;
2525 }
2526
2527 #ifdef YP
2528 /*ARGSUSED*/
2529 static struct addrinfo *
_yphostent(char * line,const struct addrinfo * pai)2530 _yphostent(char *line, const struct addrinfo *pai)
2531 {
2532 struct addrinfo sentinel, *cur;
2533 struct addrinfo hints, *res, *res0;
2534 int error;
2535 char *p = line;
2536 const char *addr, *canonname;
2537 char *nextline;
2538 char *cp;
2539
2540 addr = canonname = NULL;
2541
2542 memset(&sentinel, 0, sizeof(sentinel));
2543 cur = &sentinel;
2544
2545 nextline:
2546 /* terminate line */
2547 cp = strchr(p, '\n');
2548 if (cp) {
2549 *cp++ = '\0';
2550 nextline = cp;
2551 } else
2552 nextline = NULL;
2553
2554 cp = strpbrk(p, " \t");
2555 if (cp == NULL) {
2556 if (canonname == NULL)
2557 return (NULL);
2558 else
2559 goto done;
2560 }
2561 *cp++ = '\0';
2562
2563 addr = p;
2564
2565 while (cp && *cp) {
2566 if (*cp == ' ' || *cp == '\t') {
2567 cp++;
2568 continue;
2569 }
2570 if (!canonname)
2571 canonname = cp;
2572 if ((cp = strpbrk(cp, " \t")) != NULL)
2573 *cp++ = '\0';
2574 }
2575
2576 hints = *pai;
2577 hints.ai_flags = AI_NUMERICHOST;
2578 if (pai->ai_family == AF_INET6 &&
2579 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED)
2580 hints.ai_flags |= AI_V4MAPPED;
2581 error = getaddrinfo(addr, NULL, &hints, &res0);
2582 if (error == 0) {
2583 for (res = res0; res; res = res->ai_next) {
2584 /* cover it up */
2585 res->ai_flags = pai->ai_flags;
2586
2587 if (pai->ai_flags & AI_CANONNAME)
2588 (void)get_canonname(pai, res, canonname);
2589 }
2590 } else
2591 res0 = NULL;
2592 if (res0) {
2593 cur->ai_next = res0;
2594 while (cur && cur->ai_next)
2595 cur = cur->ai_next;
2596 }
2597
2598 if (nextline) {
2599 p = nextline;
2600 goto nextline;
2601 }
2602
2603 done:
2604 return sentinel.ai_next;
2605 }
2606
2607 /*ARGSUSED*/
2608 static int
_yp_getaddrinfo(void * rv,void * cb_data,va_list ap)2609 _yp_getaddrinfo(void *rv, void *cb_data, va_list ap)
2610 {
2611 struct addrinfo sentinel, *cur;
2612 struct addrinfo *ai = NULL;
2613 char *ypbuf;
2614 int ypbuflen, r;
2615 const char *name;
2616 const struct addrinfo *pai;
2617 char *ypdomain;
2618
2619 if (_yp_check(&ypdomain) == 0)
2620 return NS_UNAVAIL;
2621
2622 name = va_arg(ap, char *);
2623 pai = va_arg(ap, const struct addrinfo *);
2624
2625 memset(&sentinel, 0, sizeof(sentinel));
2626 cur = &sentinel;
2627
2628 /* ipnodes.byname can hold both IPv4/v6 */
2629 r = yp_match(ypdomain, "ipnodes.byname", name,
2630 (int)strlen(name), &ypbuf, &ypbuflen);
2631 if (r == 0) {
2632 ai = _yphostent(ypbuf, pai);
2633 if (ai) {
2634 cur->ai_next = ai;
2635 while (cur && cur->ai_next)
2636 cur = cur->ai_next;
2637 }
2638 free(ypbuf);
2639 }
2640
2641 if (ai != NULL) {
2642 struct sockaddr_in6 *sin6;
2643
2644 switch (ai->ai_family) {
2645 case AF_INET:
2646 goto done;
2647 case AF_INET6:
2648 sin6 = (struct sockaddr_in6 *)ai->ai_addr;
2649 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
2650 goto done;
2651 break;
2652 }
2653 }
2654
2655 /* hosts.byname is only for IPv4 (Solaris8) */
2656 if (pai->ai_family == AF_UNSPEC || pai->ai_family == AF_INET ||
2657 ((pai->ai_family == AF_INET6 &&
2658 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) &&
2659 (ai == NULL || (pai->ai_flags & AI_ALL) == AI_ALL))) {
2660 r = yp_match(ypdomain, "hosts.byname", name,
2661 (int)strlen(name), &ypbuf, &ypbuflen);
2662 if (r == 0) {
2663 struct addrinfo ai4;
2664
2665 ai4 = *pai;
2666 if (pai->ai_family == AF_UNSPEC)
2667 ai4.ai_family = AF_INET;
2668 ai = _yphostent(ypbuf, &ai4);
2669 if (ai) {
2670 cur->ai_next = ai;
2671 while (cur && cur->ai_next)
2672 cur = cur->ai_next;
2673 }
2674 free(ypbuf);
2675 }
2676 }
2677
2678 done:
2679 if (sentinel.ai_next == NULL) {
2680 RES_SET_H_ERRNO(__res_state(), HOST_NOT_FOUND);
2681 return NS_NOTFOUND;
2682 }
2683 *((struct addrinfo **)rv) = sentinel.ai_next;
2684 return NS_SUCCESS;
2685 }
2686 #endif
2687
2688 /* resolver logic */
2689
2690 /*
2691 * Formulate a normal query, send, and await answer.
2692 * Returned answer is placed in supplied buffer "answer".
2693 * Perform preliminary check of answer, returning success only
2694 * if no error is indicated and the answer count is nonzero.
2695 * Return the size of the response on success, -1 on error.
2696 * Error number is left in h_errno.
2697 *
2698 * Caller must parse answer and determine whether it answers the question.
2699 */
2700 static int
res_queryN(const char * name,struct res_target * target,res_state res)2701 res_queryN(const char *name, struct res_target *target, res_state res)
2702 {
2703 u_char *buf;
2704 HEADER *hp;
2705 int n;
2706 u_int oflags;
2707 struct res_target *t;
2708 int rcode;
2709 int ancount;
2710
2711 rcode = NOERROR;
2712 ancount = 0;
2713
2714 buf = malloc(MAXPACKET);
2715 if (!buf) {
2716 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2717 return -1;
2718 }
2719
2720 for (t = target; t; t = t->next) {
2721 int class, type;
2722 u_char *answer;
2723 int anslen;
2724
2725 hp = (HEADER *)(void *)t->answer;
2726
2727 /* make it easier... */
2728 class = t->qclass;
2729 type = t->qtype;
2730 answer = t->answer;
2731 anslen = t->anslen;
2732
2733 oflags = res->_flags;
2734
2735 again:
2736 hp->rcode = NOERROR; /* default */
2737
2738 #ifdef DEBUG
2739 if (res->options & RES_DEBUG)
2740 printf(";; res_query(%s, %d, %d)\n", name, class, type);
2741 #endif
2742
2743 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
2744 buf, MAXPACKET);
2745 if (n > 0 && (res->_flags & RES_F_EDNS0ERR) == 0 &&
2746 (res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0U)
2747 n = res_nopt(res, n, buf, MAXPACKET, anslen);
2748 if (n <= 0) {
2749 #ifdef DEBUG
2750 if (res->options & RES_DEBUG)
2751 printf(";; res_query: mkquery failed\n");
2752 #endif
2753 free(buf);
2754 RES_SET_H_ERRNO(res, NO_RECOVERY);
2755 return (n);
2756 }
2757 n = res_nsend(res, buf, n, answer, anslen);
2758 if (n < 0) {
2759 /*
2760 * if the query choked with EDNS0, retry
2761 * without EDNS0
2762 */
2763 if ((res->options & (RES_USE_EDNS0|RES_USE_DNSSEC))
2764 != 0U &&
2765 ((oflags ^ res->_flags) & RES_F_EDNS0ERR) != 0) {
2766 res->_flags |= RES_F_EDNS0ERR;
2767 if (res->options & RES_DEBUG)
2768 printf(";; res_nquery: retry without EDNS0\n");
2769 goto again;
2770 }
2771 rcode = hp->rcode; /* record most recent error */
2772 #ifdef DEBUG
2773 if (res->options & RES_DEBUG)
2774 printf(";; res_query: send error\n");
2775 #endif
2776 continue;
2777 }
2778
2779 if (n > anslen)
2780 hp->rcode = FORMERR; /* XXX not very informative */
2781 if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
2782 rcode = hp->rcode; /* record most recent error */
2783 #ifdef DEBUG
2784 if (res->options & RES_DEBUG)
2785 printf(";; rcode = %u, ancount=%u\n", hp->rcode,
2786 ntohs(hp->ancount));
2787 #endif
2788 continue;
2789 }
2790
2791 ancount += ntohs(hp->ancount);
2792
2793 t->n = n;
2794 }
2795
2796 free(buf);
2797
2798 if (ancount == 0) {
2799 switch (rcode) {
2800 case NXDOMAIN:
2801 RES_SET_H_ERRNO(res, HOST_NOT_FOUND);
2802 break;
2803 case SERVFAIL:
2804 RES_SET_H_ERRNO(res, TRY_AGAIN);
2805 break;
2806 case NOERROR:
2807 RES_SET_H_ERRNO(res, NO_DATA);
2808 break;
2809 case FORMERR:
2810 case NOTIMP:
2811 case REFUSED:
2812 default:
2813 RES_SET_H_ERRNO(res, NO_RECOVERY);
2814 break;
2815 }
2816 return (-1);
2817 }
2818 return (ancount);
2819 }
2820
2821 /*
2822 * Formulate a normal query, send, and retrieve answer in supplied buffer.
2823 * Return the size of the response on success, -1 on error.
2824 * If enabled, implement search rules until answer or unrecoverable failure
2825 * is detected. Error code, if any, is left in h_errno.
2826 */
2827 static int
res_searchN(const char * name,struct res_target * target,res_state res)2828 res_searchN(const char *name, struct res_target *target, res_state res)
2829 {
2830 const char *cp, * const *domain;
2831 HEADER *hp = (HEADER *)(void *)target->answer; /*XXX*/
2832 u_int dots;
2833 int trailing_dot, ret, saved_herrno;
2834 int got_nodata = 0, got_servfail = 0, root_on_list = 0;
2835 int tried_as_is = 0;
2836 int searched = 0;
2837 char abuf[MAXDNAME];
2838
2839 errno = 0;
2840 RES_SET_H_ERRNO(res, HOST_NOT_FOUND); /* default, if we never query */
2841 dots = 0;
2842 for (cp = name; *cp; cp++)
2843 dots += (*cp == '.');
2844 trailing_dot = 0;
2845 if (cp > name && *--cp == '.')
2846 trailing_dot++;
2847
2848 /*
2849 * if there aren't any dots, it could be a user-level alias
2850 */
2851 if (!dots &&
2852 (cp = res_hostalias(res, name, abuf, sizeof(abuf))) != NULL)
2853 return (res_queryN(cp, target, res));
2854
2855 /*
2856 * If there are enough dots in the name, let's just give it a
2857 * try 'as is'. The threshold can be set with the "ndots" option.
2858 * Also, query 'as is', if there is a trailing dot in the name.
2859 */
2860 saved_herrno = -1;
2861 if (dots >= res->ndots || trailing_dot) {
2862 ret = res_querydomainN(name, NULL, target, res);
2863 if (ret > 0 || trailing_dot)
2864 return (ret);
2865 if (errno == ECONNREFUSED) {
2866 RES_SET_H_ERRNO(res, TRY_AGAIN);
2867 return (-1);
2868 }
2869 switch (res->res_h_errno) {
2870 case NO_DATA:
2871 case HOST_NOT_FOUND:
2872 break;
2873 case TRY_AGAIN:
2874 if (hp->rcode == SERVFAIL)
2875 break;
2876 /* FALLTHROUGH */
2877 default:
2878 return (-1);
2879 }
2880 saved_herrno = res->res_h_errno;
2881 tried_as_is++;
2882 }
2883
2884 /*
2885 * We do at least one level of search if
2886 * - there is no dot and RES_DEFNAME is set, or
2887 * - there is at least one dot, there is no trailing dot,
2888 * and RES_DNSRCH is set.
2889 */
2890 if ((!dots && (res->options & RES_DEFNAMES)) ||
2891 (dots && !trailing_dot && (res->options & RES_DNSRCH))) {
2892 int done = 0;
2893
2894 for (domain = (const char * const *)res->dnsrch;
2895 *domain && !done;
2896 domain++) {
2897 searched = 1;
2898
2899 if (domain[0][0] == '\0' ||
2900 (domain[0][0] == '.' && domain[0][1] == '\0'))
2901 root_on_list++;
2902
2903 if (root_on_list && tried_as_is)
2904 continue;
2905
2906 ret = res_querydomainN(name, *domain, target, res);
2907 if (ret > 0)
2908 return (ret);
2909
2910 /*
2911 * If no server present, give up.
2912 * If name isn't found in this domain,
2913 * keep trying higher domains in the search list
2914 * (if that's enabled).
2915 * On a NO_DATA error, keep trying, otherwise
2916 * a wildcard entry of another type could keep us
2917 * from finding this entry higher in the domain.
2918 * If we get some other error (negative answer or
2919 * server failure), then stop searching up,
2920 * but try the input name below in case it's
2921 * fully-qualified.
2922 */
2923 if (errno == ECONNREFUSED) {
2924 RES_SET_H_ERRNO(res, TRY_AGAIN);
2925 return (-1);
2926 }
2927
2928 switch (res->res_h_errno) {
2929 case NO_DATA:
2930 got_nodata++;
2931 /* FALLTHROUGH */
2932 case HOST_NOT_FOUND:
2933 /* keep trying */
2934 break;
2935 case TRY_AGAIN:
2936 got_servfail++;
2937 if (hp->rcode == SERVFAIL) {
2938 /* try next search element, if any */
2939 break;
2940 }
2941 /* FALLTHROUGH */
2942 default:
2943 /* anything else implies that we're done */
2944 done++;
2945 }
2946 /*
2947 * if we got here for some reason other than DNSRCH,
2948 * we only wanted one iteration of the loop, so stop.
2949 */
2950 if (!(res->options & RES_DNSRCH))
2951 done++;
2952 }
2953 }
2954
2955 switch (res->res_h_errno) {
2956 case NO_DATA:
2957 case HOST_NOT_FOUND:
2958 break;
2959 case TRY_AGAIN:
2960 if (hp->rcode == SERVFAIL)
2961 break;
2962 /* FALLTHROUGH */
2963 default:
2964 goto giveup;
2965 }
2966
2967 /*
2968 * If the query has not already been tried as is then try it
2969 * unless RES_NOTLDQUERY is set and there were no dots.
2970 */
2971 if ((dots || !searched || !(res->options & RES_NOTLDQUERY)) &&
2972 !(tried_as_is || root_on_list)) {
2973 ret = res_querydomainN(name, NULL, target, res);
2974 if (ret > 0)
2975 return (ret);
2976 }
2977
2978 /*
2979 * if we got here, we didn't satisfy the search.
2980 * if we did an initial full query, return that query's h_errno
2981 * (note that we wouldn't be here if that query had succeeded).
2982 * else if we ever got a nodata, send that back as the reason.
2983 * else send back meaningless h_errno, that being the one from
2984 * the last DNSRCH we did.
2985 */
2986 giveup:
2987 if (saved_herrno != -1)
2988 RES_SET_H_ERRNO(res, saved_herrno);
2989 else if (got_nodata)
2990 RES_SET_H_ERRNO(res, NO_DATA);
2991 else if (got_servfail)
2992 RES_SET_H_ERRNO(res, TRY_AGAIN);
2993 return (-1);
2994 }
2995
2996 /*
2997 * Perform a call on res_query on the concatenation of name and domain,
2998 * removing a trailing dot from name if domain is NULL.
2999 */
3000 static int
res_querydomainN(const char * name,const char * domain,struct res_target * target,res_state res)3001 res_querydomainN(const char *name, const char *domain,
3002 struct res_target *target, res_state res)
3003 {
3004 char nbuf[MAXDNAME];
3005 const char *longname = nbuf;
3006 size_t n, d;
3007
3008 #ifdef DEBUG
3009 if (res->options & RES_DEBUG)
3010 printf(";; res_querydomain(%s, %s)\n",
3011 name, domain?domain:"<Nil>");
3012 #endif
3013 if (domain == NULL) {
3014 /*
3015 * Check for trailing '.';
3016 * copy without '.' if present.
3017 */
3018 n = strlen(name);
3019 if (n >= MAXDNAME) {
3020 RES_SET_H_ERRNO(res, NO_RECOVERY);
3021 return (-1);
3022 }
3023 if (n > 0 && name[--n] == '.') {
3024 strncpy(nbuf, name, n);
3025 nbuf[n] = '\0';
3026 } else
3027 longname = name;
3028 } else {
3029 n = strlen(name);
3030 d = strlen(domain);
3031 if (n + d + 1 >= MAXDNAME) {
3032 RES_SET_H_ERRNO(res, NO_RECOVERY);
3033 return (-1);
3034 }
3035 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
3036 }
3037 return (res_queryN(longname, target, res));
3038 }
3039