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(const 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 *hostname2 = NULL, *addr;
1342 const char *cp, *scope;
1343 struct sockaddr_in6 *sin6;
1344
1345 afd = find_afd(pai->ai_family);
1346 if (afd == NULL)
1347 return 0;
1348
1349 if (!afd->a_scoped)
1350 return explore_numeric(pai, hostname, servname, res, hostname);
1351
1352 cp = strchr(hostname, SCOPE_DELIMITER);
1353 if (cp == NULL)
1354 return explore_numeric(pai, hostname, servname, res, hostname);
1355
1356 /*
1357 * Handle special case of <scoped_address><delimiter><scope id>
1358 */
1359 hostname2 = strdup(hostname);
1360 if (hostname2 == NULL)
1361 return EAI_MEMORY;
1362 /* terminate at the delimiter */
1363 hostname2[cp - hostname] = '\0';
1364 addr = hostname2;
1365 scope = cp + 1;
1366
1367 error = explore_numeric(pai, addr, servname, res, hostname);
1368 if (error == 0) {
1369 u_int32_t scopeid;
1370
1371 for (cur = *res; cur; cur = cur->ai_next) {
1372 if (cur->ai_family != AF_INET6)
1373 continue;
1374 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
1375 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
1376 free(hostname2);
1377 freeaddrinfo(*res);
1378 *res = NULL;
1379 return(EAI_NONAME); /* XXX: is return OK? */
1380 }
1381 sin6->sin6_scope_id = scopeid;
1382 }
1383 }
1384
1385 free(hostname2);
1386
1387 if (error && *res) {
1388 freeaddrinfo(*res);
1389 *res = NULL;
1390 }
1391 return error;
1392 #endif
1393 }
1394
1395 static int
get_canonname(const struct addrinfo * pai,struct addrinfo * ai,const char * str)1396 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
1397 {
1398 if ((pai->ai_flags & AI_CANONNAME) != 0) {
1399 ai->ai_canonname = strdup(str);
1400 if (ai->ai_canonname == NULL)
1401 return EAI_MEMORY;
1402 }
1403 return 0;
1404 }
1405
1406 static struct addrinfo *
get_ai(const struct addrinfo * pai,const struct afd * afd,const char * addr)1407 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
1408 {
1409 char *p;
1410 struct addrinfo *ai;
1411 #ifdef INET6
1412 struct in6_addr mapaddr;
1413
1414 if (afd->a_af == AF_INET && (pai->ai_flags & AI_V4MAPPED) != 0) {
1415 afd = &afdl[N_INET6];
1416 _map_v4v6_address(addr, (char *)&mapaddr);
1417 addr = (char *)&mapaddr;
1418 }
1419 #endif
1420
1421 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
1422 + (afd->a_socklen));
1423 if (ai == NULL)
1424 return NULL;
1425
1426 memcpy(ai, pai, sizeof(struct addrinfo));
1427 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1428 memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1429 ai->ai_addr->sa_len = afd->a_socklen;
1430 ai->ai_addrlen = afd->a_socklen;
1431 if (ai->ai_family == PF_LOCAL) {
1432 size_t n = strnlen(addr, afd->a_addrlen);
1433
1434 ai->ai_addrlen -= afd->a_addrlen - n;
1435 ai->ai_addr->sa_len -= afd->a_addrlen - n;
1436 }
1437 ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1438 p = (char *)(void *)(ai->ai_addr);
1439 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
1440 return ai;
1441 }
1442
1443 /* XXX need to malloc() the same way we do from other functions! */
1444 static struct addrinfo *
copy_ai(const struct addrinfo * pai)1445 copy_ai(const struct addrinfo *pai)
1446 {
1447 struct addrinfo *ai;
1448 size_t l;
1449
1450 l = sizeof(*ai) + pai->ai_addrlen;
1451 if ((ai = calloc(1, l)) == NULL)
1452 return NULL;
1453 memcpy(ai, pai, sizeof(*ai));
1454 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1455 memcpy(ai->ai_addr, pai->ai_addr, pai->ai_addrlen);
1456
1457 if (pai->ai_canonname) {
1458 l = strlen(pai->ai_canonname) + 1;
1459 if ((ai->ai_canonname = malloc(l)) == NULL) {
1460 free(ai);
1461 return NULL;
1462 }
1463 strlcpy(ai->ai_canonname, pai->ai_canonname, l);
1464 } else {
1465 /* just to make sure */
1466 ai->ai_canonname = NULL;
1467 }
1468
1469 ai->ai_next = NULL;
1470
1471 return ai;
1472 }
1473
1474 static int
get_portmatch(const struct addrinfo * ai,const char * servname)1475 get_portmatch(const struct addrinfo *ai, const char *servname)
1476 {
1477
1478 /* get_port does not touch first argument when matchonly == 1. */
1479 /* LINTED const cast */
1480 return get_port((struct addrinfo *)ai, servname, 1);
1481 }
1482
1483 static int
get_port(struct addrinfo * ai,const char * servname,int matchonly)1484 get_port(struct addrinfo *ai, const char *servname, int matchonly)
1485 {
1486 const char *proto;
1487 struct servent *sp;
1488 int port, error;
1489 int allownumeric;
1490
1491 if (servname == NULL)
1492 return 0;
1493 switch (ai->ai_family) {
1494 case AF_LOCAL:
1495 /* AF_LOCAL ignores servname silently. */
1496 return (0);
1497 case AF_INET:
1498 #ifdef AF_INET6
1499 case AF_INET6:
1500 #endif
1501 break;
1502 default:
1503 return 0;
1504 }
1505
1506 switch (ai->ai_socktype) {
1507 case SOCK_RAW:
1508 return EAI_SERVICE;
1509 case SOCK_DGRAM:
1510 case SOCK_STREAM:
1511 case SOCK_SEQPACKET:
1512 allownumeric = 1;
1513 break;
1514 case ANY:
1515 switch (ai->ai_family) {
1516 case AF_INET:
1517 #ifdef AF_INET6
1518 case AF_INET6:
1519 #endif
1520 allownumeric = 1;
1521 break;
1522 default:
1523 allownumeric = 0;
1524 break;
1525 }
1526 break;
1527 default:
1528 return EAI_SOCKTYPE;
1529 }
1530
1531 error = str2number(servname, &port);
1532 if (error == 0) {
1533 if (!allownumeric)
1534 return EAI_SERVICE;
1535 if (port < 0 || port > 65535)
1536 return EAI_SERVICE;
1537 port = htons(port);
1538 } else {
1539 if (ai->ai_flags & AI_NUMERICSERV)
1540 return EAI_NONAME;
1541
1542 switch (ai->ai_protocol) {
1543 case IPPROTO_UDP:
1544 proto = "udp";
1545 break;
1546 case IPPROTO_TCP:
1547 proto = "tcp";
1548 break;
1549 case IPPROTO_SCTP:
1550 proto = "sctp";
1551 break;
1552 case IPPROTO_UDPLITE:
1553 proto = "udplite";
1554 break;
1555 default:
1556 proto = NULL;
1557 break;
1558 }
1559
1560 if ((sp = getservbyname(servname, proto)) == NULL)
1561 return EAI_SERVICE;
1562 port = sp->s_port;
1563 }
1564
1565 if (!matchonly) {
1566 switch (ai->ai_family) {
1567 case AF_INET:
1568 ((struct sockaddr_in *)(void *)
1569 ai->ai_addr)->sin_port = port;
1570 break;
1571 #ifdef INET6
1572 case AF_INET6:
1573 ((struct sockaddr_in6 *)(void *)
1574 ai->ai_addr)->sin6_port = port;
1575 break;
1576 #endif
1577 }
1578 }
1579
1580 return 0;
1581 }
1582
1583 static const struct afd *
find_afd(int af)1584 find_afd(int af)
1585 {
1586 const struct afd *afd;
1587
1588 if (af == PF_UNSPEC)
1589 return NULL;
1590 for (afd = afdl; afd->a_af; afd++) {
1591 if (afd->a_af == af)
1592 return afd;
1593 }
1594 return NULL;
1595 }
1596
1597 /*
1598 * RFC 3493: AI_ADDRCONFIG check. Determines which address families are
1599 * configured on the local system and correlates with pai->ai_family value.
1600 * If an address family is not configured on the system, it will not be
1601 * queried for. For this purpose, loopback addresses are not considered
1602 * configured addresses.
1603 *
1604 * XXX PF_UNSPEC -> PF_INET6 + PF_INET mapping needs to be in sync with
1605 * _dns_getaddrinfo.
1606 */
1607 static int
addrconfig(struct addrinfo * pai)1608 addrconfig(struct addrinfo *pai)
1609 {
1610 struct ifaddrs *ifaddrs, *ifa;
1611 struct sockaddr_in *sin;
1612 #ifdef INET6
1613 struct sockaddr_in6 *sin6;
1614 #endif
1615 int seen_inet = 0, seen_inet6 = 0;
1616
1617 if (getifaddrs(&ifaddrs) != 0)
1618 return (0);
1619
1620 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
1621 if (ifa->ifa_addr == NULL || (ifa->ifa_flags & IFF_UP) == 0)
1622 continue;
1623 switch (ifa->ifa_addr->sa_family) {
1624 case AF_INET:
1625 if (seen_inet)
1626 continue;
1627 sin = (struct sockaddr_in *)(ifa->ifa_addr);
1628 if (htonl(sin->sin_addr.s_addr) == INADDR_LOOPBACK)
1629 continue;
1630 seen_inet = 1;
1631 break;
1632 #ifdef INET6
1633 case AF_INET6:
1634 if (seen_inet6)
1635 continue;
1636 sin6 = (struct sockaddr_in6 *)(ifa->ifa_addr);
1637 if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
1638 continue;
1639 if ((ifa->ifa_flags & IFT_LOOP) != 0 &&
1640 IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
1641 continue;
1642 if (is_ifdisabled(ifa->ifa_name))
1643 continue;
1644 seen_inet6 = 1;
1645 break;
1646 #endif
1647 }
1648 }
1649 freeifaddrs(ifaddrs);
1650
1651 switch(pai->ai_family) {
1652 case AF_INET6:
1653 return (seen_inet6);
1654 case AF_INET:
1655 return (seen_inet);
1656 case AF_UNSPEC:
1657 if (seen_inet == seen_inet6)
1658 return (seen_inet);
1659 pai->ai_family = seen_inet ? AF_INET : AF_INET6;
1660 return (1);
1661 }
1662 return (1);
1663 }
1664
1665 #ifdef INET6
1666 static int
is_ifdisabled(char * name)1667 is_ifdisabled(char *name)
1668 {
1669 struct in6_ndireq nd;
1670 int fd;
1671
1672 if ((fd = _socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0)) < 0)
1673 return (-1);
1674 memset(&nd, 0, sizeof(nd));
1675 strlcpy(nd.ifname, name, sizeof(nd.ifname));
1676 if (_ioctl(fd, SIOCGIFINFO_IN6, &nd) < 0) {
1677 _close(fd);
1678 return (-1);
1679 }
1680 _close(fd);
1681 return ((nd.ndi.flags & ND6_IFF_IFDISABLED) != 0);
1682 }
1683
1684 /* convert a string to a scope identifier. XXX: IPv6 specific */
1685 static int
ip6_str2scopeid(const char * scope,struct sockaddr_in6 * sin6,u_int32_t * scopeid)1686 ip6_str2scopeid(const char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
1687 {
1688 u_long lscopeid;
1689 struct in6_addr *a6;
1690 char *ep;
1691
1692 a6 = &sin6->sin6_addr;
1693
1694 /* empty scopeid portion is invalid */
1695 if (*scope == '\0')
1696 return -1;
1697
1698 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) ||
1699 IN6_IS_ADDR_MC_NODELOCAL(a6)) {
1700 /*
1701 * We currently assume a one-to-one mapping between links
1702 * and interfaces, so we simply use interface indices for
1703 * like-local scopes.
1704 */
1705 *scopeid = if_nametoindex(scope);
1706 if (*scopeid == 0)
1707 goto trynumeric;
1708 return 0;
1709 }
1710
1711 /* still unclear about literal, allow numeric only - placeholder */
1712 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1713 goto trynumeric;
1714 if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1715 goto trynumeric;
1716 else
1717 goto trynumeric; /* global */
1718
1719 /* try to convert to a numeric id as a last resort */
1720 trynumeric:
1721 errno = 0;
1722 lscopeid = strtoul(scope, &ep, 10);
1723 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
1724 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
1725 return 0;
1726 else
1727 return -1;
1728 }
1729 #endif
1730
1731
1732 #ifdef NS_CACHING
1733 static int
addrinfo_id_func(char * buffer,size_t * buffer_size,va_list ap,void * cache_mdata)1734 addrinfo_id_func(char *buffer, size_t *buffer_size, va_list ap,
1735 void *cache_mdata)
1736 {
1737 res_state statp;
1738 u_long res_options;
1739
1740 const int op_id = 0; /* identifies the getaddrinfo for the cache */
1741 char *hostname;
1742 struct addrinfo *hints;
1743
1744 char *p;
1745 int ai_flags, ai_family, ai_socktype, ai_protocol;
1746 size_t desired_size, size;
1747
1748 statp = __res_state();
1749 res_options = statp->options & (RES_RECURSE | RES_DEFNAMES |
1750 RES_DNSRCH | RES_NOALIASES | RES_USE_INET6);
1751
1752 hostname = va_arg(ap, char *);
1753 hints = va_arg(ap, struct addrinfo *);
1754
1755 desired_size = sizeof(res_options) + sizeof(int) + sizeof(int) * 4;
1756 if (hostname != NULL) {
1757 size = strlen(hostname);
1758 desired_size += size + 1;
1759 } else
1760 size = 0;
1761
1762 if (desired_size > *buffer_size) {
1763 *buffer_size = desired_size;
1764 return (NS_RETURN);
1765 }
1766
1767 if (hints == NULL)
1768 ai_flags = ai_family = ai_socktype = ai_protocol = 0;
1769 else {
1770 ai_flags = hints->ai_flags;
1771 ai_family = hints->ai_family;
1772 ai_socktype = hints->ai_socktype;
1773 ai_protocol = hints->ai_protocol;
1774 }
1775
1776 p = buffer;
1777 memcpy(p, &res_options, sizeof(res_options));
1778 p += sizeof(res_options);
1779
1780 memcpy(p, &op_id, sizeof(int));
1781 p += sizeof(int);
1782
1783 memcpy(p, &ai_flags, sizeof(int));
1784 p += sizeof(int);
1785
1786 memcpy(p, &ai_family, sizeof(int));
1787 p += sizeof(int);
1788
1789 memcpy(p, &ai_socktype, sizeof(int));
1790 p += sizeof(int);
1791
1792 memcpy(p, &ai_protocol, sizeof(int));
1793 p += sizeof(int);
1794
1795 if (hostname != NULL)
1796 memcpy(p, hostname, size);
1797
1798 *buffer_size = desired_size;
1799 return (NS_SUCCESS);
1800 }
1801
1802 static int
addrinfo_marshal_func(char * buffer,size_t * buffer_size,void * retval,va_list ap,void * cache_mdata)1803 addrinfo_marshal_func(char *buffer, size_t *buffer_size, void *retval,
1804 va_list ap, void *cache_mdata)
1805 {
1806 struct addrinfo *ai, *cai;
1807 char *p;
1808 size_t desired_size, size, ai_size;
1809
1810 ai = *((struct addrinfo **)retval);
1811
1812 desired_size = sizeof(size_t);
1813 ai_size = 0;
1814 for (cai = ai; cai != NULL; cai = cai->ai_next) {
1815 desired_size += sizeof(struct addrinfo) + cai->ai_addrlen;
1816 if (cai->ai_canonname != NULL)
1817 desired_size += sizeof(size_t) +
1818 strlen(cai->ai_canonname);
1819 ++ai_size;
1820 }
1821
1822 if (desired_size > *buffer_size) {
1823 /* this assignment is here for future use */
1824 errno = ERANGE;
1825 *buffer_size = desired_size;
1826 return (NS_RETURN);
1827 }
1828
1829 memset(buffer, 0, desired_size);
1830 p = buffer;
1831
1832 memcpy(p, &ai_size, sizeof(size_t));
1833 p += sizeof(size_t);
1834 for (cai = ai; cai != NULL; cai = cai->ai_next) {
1835 memcpy(p, cai, sizeof(struct addrinfo));
1836 p += sizeof(struct addrinfo);
1837
1838 memcpy(p, cai->ai_addr, cai->ai_addrlen);
1839 p += cai->ai_addrlen;
1840
1841 if (cai->ai_canonname != NULL) {
1842 size = strlen(cai->ai_canonname);
1843 memcpy(p, &size, sizeof(size_t));
1844 p += sizeof(size_t);
1845
1846 memcpy(p, cai->ai_canonname, size);
1847 p += size;
1848 }
1849 }
1850
1851 return (NS_SUCCESS);
1852 }
1853
1854 static int
addrinfo_unmarshal_func(char * buffer,size_t buffer_size,void * retval,va_list ap,void * cache_mdata)1855 addrinfo_unmarshal_func(char *buffer, size_t buffer_size, void *retval,
1856 va_list ap, void *cache_mdata)
1857 {
1858 struct addrinfo new_ai, *result, *sentinel, *lasts;
1859
1860 char *p;
1861 size_t ai_size, ai_i, size;
1862
1863 p = buffer;
1864 memcpy(&ai_size, p, sizeof(size_t));
1865 p += sizeof(size_t);
1866
1867 result = NULL;
1868 lasts = NULL;
1869 for (ai_i = 0; ai_i < ai_size; ++ai_i) {
1870 memcpy(&new_ai, p, sizeof(struct addrinfo));
1871 p += sizeof(struct addrinfo);
1872 size = new_ai.ai_addrlen + sizeof(struct addrinfo) +
1873 _ALIGNBYTES;
1874
1875 sentinel = calloc(1, size);
1876
1877 memcpy(sentinel, &new_ai, sizeof(struct addrinfo));
1878 sentinel->ai_addr = (struct sockaddr *)_ALIGN((char *)sentinel +
1879 sizeof(struct addrinfo));
1880
1881 memcpy(sentinel->ai_addr, p, new_ai.ai_addrlen);
1882 p += new_ai.ai_addrlen;
1883
1884 if (new_ai.ai_canonname != NULL) {
1885 memcpy(&size, p, sizeof(size_t));
1886 p += sizeof(size_t);
1887
1888 sentinel->ai_canonname = calloc(1, size + 1);
1889
1890 memcpy(sentinel->ai_canonname, p, size);
1891 p += size;
1892 }
1893
1894 if (result == NULL) {
1895 result = sentinel;
1896 lasts = sentinel;
1897 } else {
1898 lasts->ai_next = sentinel;
1899 lasts = sentinel;
1900 }
1901 }
1902
1903 *((struct addrinfo **)retval) = result;
1904 return (NS_SUCCESS);
1905 }
1906 #endif /* NS_CACHING */
1907
1908 /*
1909 * FQDN hostname, DNS lookup
1910 */
1911 static int
explore_fqdn(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res)1912 explore_fqdn(const struct addrinfo *pai, const char *hostname,
1913 const char *servname, struct addrinfo **res)
1914 {
1915 struct addrinfo *result;
1916 struct addrinfo *cur;
1917 int error = 0;
1918
1919 #ifdef NS_CACHING
1920 static const nss_cache_info cache_info =
1921 NS_COMMON_CACHE_INFO_INITIALIZER(
1922 hosts, NULL, addrinfo_id_func, addrinfo_marshal_func,
1923 addrinfo_unmarshal_func);
1924 #endif
1925 static const ns_dtab dtab[] = {
1926 NS_FILES_CB(_files_getaddrinfo, NULL)
1927 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
1928 NS_NIS_CB(_yp_getaddrinfo, NULL)
1929 #ifdef NS_CACHING
1930 NS_CACHE_CB(&cache_info)
1931 #endif
1932 { 0 }
1933 };
1934
1935 result = NULL;
1936
1937 /*
1938 * if the servname does not match socktype/protocol, ignore it.
1939 */
1940 if (get_portmatch(pai, servname) != 0)
1941 return 0;
1942
1943 switch (_nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
1944 default_dns_files, hostname, pai)) {
1945 case NS_TRYAGAIN:
1946 error = EAI_AGAIN;
1947 goto free;
1948 case NS_UNAVAIL:
1949 error = EAI_FAIL;
1950 goto free;
1951 case NS_NOTFOUND:
1952 error = EAI_NONAME;
1953 goto free;
1954 case NS_ADDRFAMILY:
1955 error = EAI_ADDRFAMILY;
1956 goto free;
1957 case NS_SUCCESS:
1958 error = 0;
1959 for (cur = result; cur; cur = cur->ai_next) {
1960 GET_PORT(cur, servname);
1961 /* canonname should be filled already */
1962 }
1963 break;
1964 }
1965
1966 *res = result;
1967
1968 return 0;
1969
1970 free:
1971 if (result)
1972 freeaddrinfo(result);
1973 return error;
1974 }
1975
1976 #ifdef DEBUG
1977 static const char AskedForGot[] =
1978 "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1979 #endif
1980
1981 static struct addrinfo *
getanswer(const querybuf * answer,int anslen,const char * qname,int qtype,const struct addrinfo * pai,res_state res)1982 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
1983 const struct addrinfo *pai, res_state res)
1984 {
1985 struct addrinfo sentinel, *cur;
1986 struct addrinfo ai;
1987 const struct afd *afd;
1988 char *canonname;
1989 const HEADER *hp;
1990 const u_char *cp;
1991 int n;
1992 const u_char *eom;
1993 char *bp, *ep;
1994 int type, class, ancount, qdcount;
1995 int haveanswer, had_error;
1996 char tbuf[MAXDNAME];
1997 int (*name_ok)(const char *);
1998 char hostbuf[8*1024];
1999
2000 memset(&sentinel, 0, sizeof(sentinel));
2001 cur = &sentinel;
2002
2003 canonname = NULL;
2004 eom = answer->buf + anslen;
2005 switch (qtype) {
2006 case T_A:
2007 case T_AAAA:
2008 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
2009 name_ok = res_hnok;
2010 break;
2011 default:
2012 return (NULL); /* XXX should be abort(); */
2013 }
2014 /*
2015 * find first satisfactory answer
2016 */
2017 hp = &answer->hdr;
2018 ancount = ntohs(hp->ancount);
2019 qdcount = ntohs(hp->qdcount);
2020 bp = hostbuf;
2021 ep = hostbuf + sizeof hostbuf;
2022 cp = answer->buf + HFIXEDSZ;
2023 if (qdcount != 1) {
2024 RES_SET_H_ERRNO(res, NO_RECOVERY);
2025 return (NULL);
2026 }
2027 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
2028 if ((n < 0) || !(*name_ok)(bp)) {
2029 RES_SET_H_ERRNO(res, NO_RECOVERY);
2030 return (NULL);
2031 }
2032 cp += n + QFIXEDSZ;
2033 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
2034 /* res_send() has already verified that the query name is the
2035 * same as the one we sent; this just gets the expanded name
2036 * (i.e., with the succeeding search-domain tacked on).
2037 */
2038 n = strlen(bp) + 1; /* for the \0 */
2039 if (n >= MAXHOSTNAMELEN) {
2040 RES_SET_H_ERRNO(res, NO_RECOVERY);
2041 return (NULL);
2042 }
2043 canonname = bp;
2044 bp += n;
2045 /* The qname can be abbreviated, but h_name is now absolute. */
2046 qname = canonname;
2047 }
2048 haveanswer = 0;
2049 had_error = 0;
2050 while (ancount-- > 0 && cp < eom && !had_error) {
2051 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
2052 if ((n < 0) || !(*name_ok)(bp)) {
2053 had_error++;
2054 continue;
2055 }
2056 cp += n; /* name */
2057 type = _getshort(cp);
2058 cp += INT16SZ; /* type */
2059 class = _getshort(cp);
2060 cp += INT16SZ + INT32SZ; /* class, TTL */
2061 n = _getshort(cp);
2062 cp += INT16SZ; /* len */
2063 if (class != C_IN) {
2064 /* XXX - debug? syslog? */
2065 cp += n;
2066 continue; /* XXX - had_error++ ? */
2067 }
2068 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
2069 type == T_CNAME) {
2070 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
2071 if ((n < 0) || !(*name_ok)(tbuf)) {
2072 had_error++;
2073 continue;
2074 }
2075 cp += n;
2076 /* Get canonical name. */
2077 n = strlen(tbuf) + 1; /* for the \0 */
2078 if (n > ep - bp || n >= MAXHOSTNAMELEN) {
2079 had_error++;
2080 continue;
2081 }
2082 strlcpy(bp, tbuf, ep - bp);
2083 canonname = bp;
2084 bp += n;
2085 continue;
2086 }
2087 if (qtype == T_ANY) {
2088 if (!(type == T_A || type == T_AAAA)) {
2089 cp += n;
2090 continue;
2091 }
2092 } else if (type != qtype) {
2093 #ifdef DEBUG
2094 if (type != T_KEY && type != T_SIG &&
2095 type != T_DNAME && type != T_RRSIG)
2096 syslog(LOG_NOTICE|LOG_AUTH,
2097 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
2098 qname, p_class(C_IN), p_type(qtype),
2099 p_type(type));
2100 #endif
2101 cp += n;
2102 continue; /* XXX - had_error++ ? */
2103 }
2104 switch (type) {
2105 case T_A:
2106 case T_AAAA:
2107 if (strcasecmp(canonname, bp) != 0) {
2108 #ifdef DEBUG
2109 syslog(LOG_NOTICE|LOG_AUTH,
2110 AskedForGot, canonname, bp);
2111 #endif
2112 cp += n;
2113 continue; /* XXX - had_error++ ? */
2114 }
2115 if (type == T_A && n != INADDRSZ) {
2116 cp += n;
2117 continue;
2118 }
2119 if (type == T_AAAA && n != IN6ADDRSZ) {
2120 cp += n;
2121 continue;
2122 }
2123 #ifdef FILTER_V4MAPPED
2124 if (type == T_AAAA) {
2125 struct in6_addr in6;
2126 memcpy(&in6, cp, sizeof(in6));
2127 if (IN6_IS_ADDR_V4MAPPED(&in6)) {
2128 cp += n;
2129 continue;
2130 }
2131 }
2132 #endif
2133 if (!haveanswer) {
2134 int nn;
2135
2136 canonname = bp;
2137 nn = strlen(bp) + 1; /* for the \0 */
2138 bp += nn;
2139 }
2140
2141 /* don't overwrite pai */
2142 ai = *pai;
2143 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
2144 afd = find_afd(ai.ai_family);
2145 if (afd == NULL) {
2146 cp += n;
2147 continue;
2148 }
2149 cur->ai_next = get_ai(&ai, afd, (const char *)cp);
2150 if (cur->ai_next == NULL)
2151 had_error++;
2152 while (cur && cur->ai_next)
2153 cur = cur->ai_next;
2154 cp += n;
2155 break;
2156 default:
2157 abort();
2158 }
2159 if (!had_error)
2160 haveanswer++;
2161 }
2162 if (haveanswer) {
2163 #if defined(RESOLVSORT)
2164 /*
2165 * We support only IPv4 address for backward
2166 * compatibility against gethostbyname(3).
2167 */
2168 if (res->nsort && qtype == T_A) {
2169 if (addr4sort(&sentinel, res) < 0) {
2170 freeaddrinfo(sentinel.ai_next);
2171 RES_SET_H_ERRNO(res, NO_RECOVERY);
2172 return NULL;
2173 }
2174 }
2175 #endif /*RESOLVSORT*/
2176 if (!canonname)
2177 (void)get_canonname(pai, sentinel.ai_next, qname);
2178 else
2179 (void)get_canonname(pai, sentinel.ai_next, canonname);
2180 RES_SET_H_ERRNO(res, NETDB_SUCCESS);
2181 return sentinel.ai_next;
2182 }
2183
2184 /*
2185 * We could have walked a CNAME chain, but the ultimate target
2186 * may not have what we looked for.
2187 */
2188 RES_SET_H_ERRNO(res, ntohs(hp->ancount) > 0 ? NO_DATA : NO_RECOVERY);
2189 return NULL;
2190 }
2191
2192 #ifdef RESOLVSORT
2193 struct addr_ptr {
2194 struct addrinfo *ai;
2195 int aval;
2196 };
2197
2198 static int
addr4sort(struct addrinfo * sentinel,res_state res)2199 addr4sort(struct addrinfo *sentinel, res_state res)
2200 {
2201 struct addrinfo *ai;
2202 struct addr_ptr *addrs, addr;
2203 struct sockaddr_in *sin;
2204 int naddrs, i, j;
2205 int needsort = 0;
2206
2207 if (!sentinel)
2208 return -1;
2209 naddrs = 0;
2210 for (ai = sentinel->ai_next; ai; ai = ai->ai_next)
2211 naddrs++;
2212 if (naddrs < 2)
2213 return 0; /* We don't need sorting. */
2214 if ((addrs = malloc(sizeof(struct addr_ptr) * naddrs)) == NULL)
2215 return -1;
2216 i = 0;
2217 for (ai = sentinel->ai_next; ai; ai = ai->ai_next) {
2218 sin = (struct sockaddr_in *)ai->ai_addr;
2219 for (j = 0; (unsigned)j < res->nsort; j++) {
2220 if (res->sort_list[j].addr.s_addr ==
2221 (sin->sin_addr.s_addr & res->sort_list[j].mask))
2222 break;
2223 }
2224 addrs[i].ai = ai;
2225 addrs[i].aval = j;
2226 if (needsort == 0 && i > 0 && j < addrs[i - 1].aval)
2227 needsort = i;
2228 i++;
2229 }
2230 if (!needsort) {
2231 free(addrs);
2232 return 0;
2233 }
2234
2235 while (needsort < naddrs) {
2236 for (j = needsort - 1; j >= 0; j--) {
2237 if (addrs[j].aval > addrs[j+1].aval) {
2238 addr = addrs[j];
2239 addrs[j] = addrs[j + 1];
2240 addrs[j + 1] = addr;
2241 } else
2242 break;
2243 }
2244 needsort++;
2245 }
2246
2247 ai = sentinel;
2248 for (i = 0; i < naddrs; ++i) {
2249 ai->ai_next = addrs[i].ai;
2250 ai = ai->ai_next;
2251 }
2252 ai->ai_next = NULL;
2253 free(addrs);
2254 return 0;
2255 }
2256 #endif /*RESOLVSORT*/
2257
2258 /*ARGSUSED*/
2259 static int
_dns_getaddrinfo(void * rv,void * cb_data,va_list ap)2260 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
2261 {
2262 struct addrinfo *ai, ai0;
2263 querybuf *buf, *buf2;
2264 const char *hostname;
2265 const struct addrinfo *pai;
2266 struct addrinfo sentinel, *cur;
2267 struct res_target q, q2;
2268 res_state res;
2269
2270 ai = NULL;
2271
2272 hostname = va_arg(ap, char *);
2273 pai = va_arg(ap, const struct addrinfo *);
2274
2275 memset(&q, 0, sizeof(q));
2276 memset(&q2, 0, sizeof(q2));
2277 memset(&sentinel, 0, sizeof(sentinel));
2278 cur = &sentinel;
2279
2280 res = __res_state();
2281
2282 buf = malloc(sizeof(*buf));
2283 if (!buf) {
2284 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2285 return NS_NOTFOUND;
2286 }
2287 buf2 = malloc(sizeof(*buf2));
2288 if (!buf2) {
2289 free(buf);
2290 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2291 return NS_NOTFOUND;
2292 }
2293
2294 if (pai->ai_family == AF_INET6 &&
2295 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) {
2296 ai0 = *pai;
2297 ai0.ai_family = AF_UNSPEC;
2298 pai = &ai0;
2299 }
2300
2301 switch (pai->ai_family) {
2302 case AF_UNSPEC:
2303 q.name = hostname;
2304 q.qclass = C_IN;
2305 q.qtype = T_A;
2306 q.answer = buf->buf;
2307 q.anslen = sizeof(buf->buf);
2308 q.next = &q2;
2309 q2.name = hostname;
2310 q2.qclass = C_IN;
2311 q2.qtype = T_AAAA;
2312 q2.answer = buf2->buf;
2313 q2.anslen = sizeof(buf2->buf);
2314 break;
2315 case AF_INET:
2316 q.name = hostname;
2317 q.qclass = C_IN;
2318 q.qtype = T_A;
2319 q.answer = buf->buf;
2320 q.anslen = sizeof(buf->buf);
2321 break;
2322 case AF_INET6:
2323 q.name = hostname;
2324 q.qclass = C_IN;
2325 q.qtype = T_AAAA;
2326 q.answer = buf->buf;
2327 q.anslen = sizeof(buf->buf);
2328 break;
2329 default:
2330 free(buf);
2331 free(buf2);
2332 return NS_UNAVAIL;
2333 }
2334
2335 if ((res->options & RES_INIT) == 0 && res_ninit(res) == -1) {
2336 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2337 free(buf);
2338 free(buf2);
2339 return NS_NOTFOUND;
2340 }
2341
2342 if (res_searchN(hostname, &q, res) < 0) {
2343 free(buf);
2344 free(buf2);
2345 switch (res->res_h_errno) {
2346 case NO_DATA:
2347 return (NS_ADDRFAMILY);
2348 case TRY_AGAIN:
2349 return (NS_TRYAGAIN);
2350 default:
2351 return (NS_NOTFOUND);
2352 }
2353 }
2354 /* prefer IPv6 */
2355 if (q.next) {
2356 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai, res);
2357 if (ai != NULL) {
2358 cur->ai_next = ai;
2359 while (cur && cur->ai_next)
2360 cur = cur->ai_next;
2361 }
2362 }
2363 if (ai == NULL || pai->ai_family != AF_UNSPEC ||
2364 (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) != AI_V4MAPPED) {
2365 ai = getanswer(buf, q.n, q.name, q.qtype, pai, res);
2366 if (ai != NULL)
2367 cur->ai_next = ai;
2368 }
2369 free(buf);
2370 free(buf2);
2371 if (sentinel.ai_next == NULL)
2372 switch (res->res_h_errno) {
2373 case HOST_NOT_FOUND:
2374 return (NS_NOTFOUND);
2375 case NO_DATA:
2376 return (NS_ADDRFAMILY);
2377 case TRY_AGAIN:
2378 return (NS_TRYAGAIN);
2379 default:
2380 return (NS_UNAVAIL);
2381 }
2382 *((struct addrinfo **)rv) = sentinel.ai_next;
2383 return (NS_SUCCESS);
2384 }
2385
2386 static void
_sethtent(FILE ** hostf)2387 _sethtent(FILE **hostf)
2388 {
2389 if (!*hostf)
2390 *hostf = fopen(_PATH_HOSTS, "re");
2391 else
2392 rewind(*hostf);
2393 }
2394
2395 static void
_endhtent(FILE ** hostf)2396 _endhtent(FILE **hostf)
2397 {
2398 if (*hostf) {
2399 (void) fclose(*hostf);
2400 *hostf = NULL;
2401 }
2402 }
2403
2404 static struct addrinfo *
_gethtent(FILE ** hostf,const char * name,const struct addrinfo * pai)2405 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai)
2406 {
2407 char *p;
2408 char *cp, *tname, *cname;
2409 struct addrinfo hints, *res0, *res;
2410 int error;
2411 const char *addr;
2412 char hostbuf[8*1024];
2413
2414 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re")))
2415 return (NULL);
2416 again:
2417 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf)))
2418 return (NULL);
2419 if (*p == '#')
2420 goto again;
2421 cp = strpbrk(p, "#\n");
2422 if (cp != NULL)
2423 *cp = '\0';
2424 if (!(cp = strpbrk(p, " \t")))
2425 goto again;
2426 *cp++ = '\0';
2427 addr = p;
2428 cname = NULL;
2429 /* if this is not something we're looking for, skip it. */
2430 while (cp && *cp) {
2431 if (*cp == ' ' || *cp == '\t') {
2432 cp++;
2433 continue;
2434 }
2435 tname = cp;
2436 if (cname == NULL)
2437 cname = cp;
2438 if ((cp = strpbrk(cp, " \t")) != NULL)
2439 *cp++ = '\0';
2440 if (strcasecmp(name, tname) == 0)
2441 goto found;
2442 }
2443 goto again;
2444
2445 found:
2446 /* we should not glob socktype/protocol here */
2447 memset(&hints, 0, sizeof(hints));
2448 hints.ai_family = pai->ai_family;
2449 hints.ai_socktype = SOCK_DGRAM;
2450 hints.ai_protocol = 0;
2451 hints.ai_flags = AI_NUMERICHOST;
2452 if (pai->ai_family == AF_INET6 &&
2453 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED)
2454 hints.ai_flags |= AI_V4MAPPED;
2455 error = getaddrinfo(addr, "0", &hints, &res0);
2456 if (error)
2457 goto again;
2458 #ifdef FILTER_V4MAPPED
2459 /* XXX should check all items in the chain */
2460 if (res0->ai_family == AF_INET6 &&
2461 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)res0->ai_addr)->sin6_addr)) {
2462 freeaddrinfo(res0);
2463 goto again;
2464 }
2465 #endif
2466 for (res = res0; res; res = res->ai_next) {
2467 /* cover it up */
2468 res->ai_flags = pai->ai_flags;
2469 res->ai_socktype = pai->ai_socktype;
2470 res->ai_protocol = pai->ai_protocol;
2471
2472 if (pai->ai_flags & AI_CANONNAME) {
2473 if (get_canonname(pai, res, cname) != 0) {
2474 freeaddrinfo(res0);
2475 goto again;
2476 }
2477 }
2478 }
2479 return res0;
2480 }
2481
2482 static struct addrinfo *
_getht(FILE ** hostf,const char * name,const struct addrinfo * pai,struct addrinfo * cur)2483 _getht(FILE **hostf, const char *name, const struct addrinfo *pai,
2484 struct addrinfo *cur)
2485 {
2486 struct addrinfo *p;
2487
2488 while ((p = _gethtent(hostf, name, pai)) != NULL) {
2489 cur->ai_next = p;
2490 while (cur && cur->ai_next)
2491 cur = cur->ai_next;
2492 }
2493 return (cur);
2494 }
2495
2496 /*ARGSUSED*/
2497 static int
_files_getaddrinfo(void * rv,void * cb_data,va_list ap)2498 _files_getaddrinfo(void *rv, void *cb_data, va_list ap)
2499 {
2500 const char *name;
2501 const struct addrinfo *pai;
2502 struct addrinfo sentinel, *cur;
2503 FILE *hostf = NULL;
2504
2505 name = va_arg(ap, char *);
2506 pai = va_arg(ap, struct addrinfo *);
2507
2508 memset(&sentinel, 0, sizeof(sentinel));
2509 cur = &sentinel;
2510
2511 _sethtent(&hostf);
2512 if (pai->ai_family == AF_INET6 &&
2513 (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) == AI_V4MAPPED) {
2514 struct addrinfo ai0 = *pai;
2515
2516 ai0.ai_flags &= ~AI_V4MAPPED;
2517 cur = _getht(&hostf, name, &ai0, cur);
2518 if (sentinel.ai_next == NULL) {
2519 _sethtent(&hostf);
2520 ai0.ai_flags |= AI_V4MAPPED;
2521 cur = _getht(&hostf, name, &ai0, cur);
2522 }
2523 } else
2524 cur = _getht(&hostf, name, pai, cur);
2525 _endhtent(&hostf);
2526
2527 *((struct addrinfo **)rv) = sentinel.ai_next;
2528 if (sentinel.ai_next == NULL)
2529 return NS_NOTFOUND;
2530 return NS_SUCCESS;
2531 }
2532
2533 #ifdef YP
2534 /*ARGSUSED*/
2535 static struct addrinfo *
_yphostent(char * line,const struct addrinfo * pai)2536 _yphostent(char *line, const struct addrinfo *pai)
2537 {
2538 struct addrinfo sentinel, *cur;
2539 struct addrinfo hints, *res, *res0;
2540 int error;
2541 char *p = line;
2542 const char *addr, *canonname;
2543 char *nextline;
2544 char *cp;
2545
2546 addr = canonname = NULL;
2547
2548 memset(&sentinel, 0, sizeof(sentinel));
2549 cur = &sentinel;
2550
2551 nextline:
2552 /* terminate line */
2553 cp = strchr(p, '\n');
2554 if (cp) {
2555 *cp++ = '\0';
2556 nextline = cp;
2557 } else
2558 nextline = NULL;
2559
2560 cp = strpbrk(p, " \t");
2561 if (cp == NULL) {
2562 if (canonname == NULL)
2563 return (NULL);
2564 else
2565 goto done;
2566 }
2567 *cp++ = '\0';
2568
2569 addr = p;
2570
2571 while (cp && *cp) {
2572 if (*cp == ' ' || *cp == '\t') {
2573 cp++;
2574 continue;
2575 }
2576 if (!canonname)
2577 canonname = cp;
2578 if ((cp = strpbrk(cp, " \t")) != NULL)
2579 *cp++ = '\0';
2580 }
2581
2582 hints = *pai;
2583 hints.ai_flags = AI_NUMERICHOST;
2584 if (pai->ai_family == AF_INET6 &&
2585 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED)
2586 hints.ai_flags |= AI_V4MAPPED;
2587 error = getaddrinfo(addr, NULL, &hints, &res0);
2588 if (error == 0) {
2589 for (res = res0; res; res = res->ai_next) {
2590 /* cover it up */
2591 res->ai_flags = pai->ai_flags;
2592
2593 if (pai->ai_flags & AI_CANONNAME)
2594 (void)get_canonname(pai, res, canonname);
2595 }
2596 } else
2597 res0 = NULL;
2598 if (res0) {
2599 cur->ai_next = res0;
2600 while (cur && cur->ai_next)
2601 cur = cur->ai_next;
2602 }
2603
2604 if (nextline) {
2605 p = nextline;
2606 goto nextline;
2607 }
2608
2609 done:
2610 return sentinel.ai_next;
2611 }
2612
2613 /*ARGSUSED*/
2614 static int
_yp_getaddrinfo(void * rv,void * cb_data,va_list ap)2615 _yp_getaddrinfo(void *rv, void *cb_data, va_list ap)
2616 {
2617 struct addrinfo sentinel, *cur;
2618 struct addrinfo *ai = NULL;
2619 char *ypbuf;
2620 int ypbuflen, r;
2621 const char *name;
2622 const struct addrinfo *pai;
2623 char *ypdomain;
2624
2625 if (_yp_check(&ypdomain) == 0)
2626 return NS_UNAVAIL;
2627
2628 name = va_arg(ap, char *);
2629 pai = va_arg(ap, const struct addrinfo *);
2630
2631 memset(&sentinel, 0, sizeof(sentinel));
2632 cur = &sentinel;
2633
2634 /* ipnodes.byname can hold both IPv4/v6 */
2635 r = yp_match(ypdomain, "ipnodes.byname", name,
2636 (int)strlen(name), &ypbuf, &ypbuflen);
2637 if (r == 0) {
2638 ai = _yphostent(ypbuf, pai);
2639 if (ai) {
2640 cur->ai_next = ai;
2641 while (cur && cur->ai_next)
2642 cur = cur->ai_next;
2643 }
2644 free(ypbuf);
2645 }
2646
2647 if (ai != NULL) {
2648 struct sockaddr_in6 *sin6;
2649
2650 switch (ai->ai_family) {
2651 case AF_INET:
2652 goto done;
2653 case AF_INET6:
2654 sin6 = (struct sockaddr_in6 *)ai->ai_addr;
2655 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
2656 goto done;
2657 break;
2658 }
2659 }
2660
2661 /* hosts.byname is only for IPv4 (Solaris8) */
2662 if (pai->ai_family == AF_UNSPEC || pai->ai_family == AF_INET ||
2663 ((pai->ai_family == AF_INET6 &&
2664 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) &&
2665 (ai == NULL || (pai->ai_flags & AI_ALL) == AI_ALL))) {
2666 r = yp_match(ypdomain, "hosts.byname", name,
2667 (int)strlen(name), &ypbuf, &ypbuflen);
2668 if (r == 0) {
2669 struct addrinfo ai4;
2670
2671 ai4 = *pai;
2672 if (pai->ai_family == AF_UNSPEC)
2673 ai4.ai_family = AF_INET;
2674 ai = _yphostent(ypbuf, &ai4);
2675 if (ai) {
2676 cur->ai_next = ai;
2677 while (cur && cur->ai_next)
2678 cur = cur->ai_next;
2679 }
2680 free(ypbuf);
2681 }
2682 }
2683
2684 done:
2685 if (sentinel.ai_next == NULL) {
2686 RES_SET_H_ERRNO(__res_state(), HOST_NOT_FOUND);
2687 return NS_NOTFOUND;
2688 }
2689 *((struct addrinfo **)rv) = sentinel.ai_next;
2690 return NS_SUCCESS;
2691 }
2692 #endif
2693
2694 /* resolver logic */
2695
2696 /*
2697 * Formulate a normal query, send, and await answer.
2698 * Returned answer is placed in supplied buffer "answer".
2699 * Perform preliminary check of answer, returning success only
2700 * if no error is indicated and the answer count is nonzero.
2701 * Return the size of the response on success, -1 on error.
2702 * Error number is left in h_errno.
2703 *
2704 * Caller must parse answer and determine whether it answers the question.
2705 */
2706 static int
res_queryN(const char * name,struct res_target * target,res_state res)2707 res_queryN(const char *name, struct res_target *target, res_state res)
2708 {
2709 u_char *buf;
2710 HEADER *hp;
2711 int n;
2712 u_int oflags;
2713 struct res_target *t;
2714 u_int rcode;
2715 int ancount;
2716
2717 /*
2718 * Extend rcode values in the scope of this function. The DNS header
2719 * rcode we use in this function (hp->rcode) is limited by 4 bits, so
2720 * anything starting from 16 is safe wrt aliasing. However, nameser.h
2721 * already has extended enum __ns_rcode, so for future safety let's use
2722 * even larger values.
2723 */
2724 #define RCODE_UNREACH 32
2725 #define RCODE_TIMEDOUT 33
2726 rcode = NOERROR;
2727 ancount = 0;
2728
2729 buf = malloc(MAXPACKET);
2730 if (!buf) {
2731 RES_SET_H_ERRNO(res, NETDB_INTERNAL);
2732 return -1;
2733 }
2734
2735 for (t = target; t; t = t->next) {
2736 int class, type;
2737 u_char *answer;
2738 int anslen;
2739
2740 hp = (HEADER *)(void *)t->answer;
2741
2742 /* make it easier... */
2743 class = t->qclass;
2744 type = t->qtype;
2745 answer = t->answer;
2746 anslen = t->anslen;
2747
2748 oflags = res->_flags;
2749
2750 again:
2751 hp->rcode = NOERROR; /* default */
2752
2753 #ifdef DEBUG
2754 if (res->options & RES_DEBUG)
2755 printf(";; res_query(%s, %d, %d)\n", name, class, type);
2756 #endif
2757
2758 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
2759 buf, MAXPACKET);
2760 if (n > 0 && (res->_flags & RES_F_EDNS0ERR) == 0 &&
2761 (res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0U)
2762 n = res_nopt(res, n, buf, MAXPACKET, anslen);
2763 if (n <= 0) {
2764 #ifdef DEBUG
2765 if (res->options & RES_DEBUG)
2766 printf(";; res_query: mkquery failed\n");
2767 #endif
2768 free(buf);
2769 RES_SET_H_ERRNO(res, NO_RECOVERY);
2770 return (n);
2771 }
2772 n = res_nsend(res, buf, n, answer, anslen);
2773 if (n < 0) {
2774 /*
2775 * if the query choked with EDNS0, retry
2776 * without EDNS0
2777 */
2778 if ((res->options & (RES_USE_EDNS0|RES_USE_DNSSEC))
2779 != 0U &&
2780 ((oflags ^ res->_flags) & RES_F_EDNS0ERR) != 0) {
2781 res->_flags |= RES_F_EDNS0ERR;
2782 if (res->options & RES_DEBUG)
2783 printf(";; res_nquery: retry without EDNS0\n");
2784 goto again;
2785 }
2786 /*
2787 * Historically if a DNS server replied with ICMP port
2788 * unreach res_nsend() would signal that with
2789 * ECONNREFUSED and the upper layers would convert that
2790 * into TRY_AGAIN. See 3a0b3b673936b and deeper.
2791 * Also, res_nsend() may set errno to ECONNREFUSED due
2792 * to internal failures. This may not be intentional,
2793 * but we also treat that as soft failures.
2794 *
2795 * A more practical case is when a DNS server(s) were
2796 * queried and didn't respond anything, which usually
2797 * indicates a soft network failure.
2798 */
2799 switch (errno) {
2800 case ECONNREFUSED:
2801 rcode = RCODE_UNREACH;
2802 break;
2803 case ETIMEDOUT:
2804 rcode = RCODE_TIMEDOUT;
2805 break;
2806 default:
2807 rcode = hp->rcode;
2808 }
2809 #ifdef DEBUG
2810 if (res->options & RES_DEBUG)
2811 printf(";; res_query: send error\n");
2812 #endif
2813 continue;
2814 }
2815
2816 if (n > anslen)
2817 hp->rcode = FORMERR; /* XXX not very informative */
2818 if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
2819 rcode = hp->rcode; /* record most recent error */
2820 #ifdef DEBUG
2821 if (res->options & RES_DEBUG)
2822 printf(";; rcode = %u, ancount=%u\n", hp->rcode,
2823 ntohs(hp->ancount));
2824 #endif
2825 continue;
2826 }
2827
2828 ancount += ntohs(hp->ancount);
2829
2830 t->n = n;
2831 }
2832
2833 free(buf);
2834
2835 if (ancount == 0) {
2836 switch (rcode) {
2837 case NXDOMAIN:
2838 RES_SET_H_ERRNO(res, HOST_NOT_FOUND);
2839 break;
2840 case RCODE_UNREACH:
2841 case RCODE_TIMEDOUT:
2842 case SERVFAIL:
2843 RES_SET_H_ERRNO(res, TRY_AGAIN);
2844 break;
2845 case NOERROR:
2846 RES_SET_H_ERRNO(res, NO_DATA);
2847 break;
2848 case FORMERR:
2849 case NOTIMP:
2850 case REFUSED:
2851 default:
2852 RES_SET_H_ERRNO(res, NO_RECOVERY);
2853 break;
2854 }
2855 return (-1);
2856 }
2857 return (ancount);
2858 }
2859
2860 /*
2861 * Formulate a normal query, send, and retrieve answer in supplied buffer.
2862 * Return the size of the response on success, -1 on error.
2863 * If enabled, implement search rules until answer or unrecoverable failure
2864 * is detected. Error code, if any, is left in h_errno.
2865 */
2866 static int
res_searchN(const char * name,struct res_target * target,res_state res)2867 res_searchN(const char *name, struct res_target *target, res_state res)
2868 {
2869 const char *cp, * const *domain;
2870 HEADER *hp = (HEADER *)(void *)target->answer; /*XXX*/
2871 u_int dots;
2872 int trailing_dot, ret, saved_herrno;
2873 int got_nodata = 0, got_servfail = 0, root_on_list = 0;
2874 int tried_as_is = 0;
2875 int searched = 0;
2876 char abuf[MAXDNAME];
2877
2878 errno = 0;
2879 RES_SET_H_ERRNO(res, HOST_NOT_FOUND); /* default, if we never query */
2880 dots = 0;
2881 for (cp = name; *cp; cp++)
2882 dots += (*cp == '.');
2883 trailing_dot = 0;
2884 if (cp > name && *--cp == '.')
2885 trailing_dot++;
2886
2887 /*
2888 * if there aren't any dots, it could be a user-level alias
2889 */
2890 if (!dots &&
2891 (cp = res_hostalias(res, name, abuf, sizeof(abuf))) != NULL)
2892 return (res_queryN(cp, target, res));
2893
2894 /*
2895 * If there are enough dots in the name, let's just give it a
2896 * try 'as is'. The threshold can be set with the "ndots" option.
2897 * Also, query 'as is', if there is a trailing dot in the name.
2898 */
2899 saved_herrno = -1;
2900 if (dots >= res->ndots || trailing_dot) {
2901 ret = res_querydomainN(name, NULL, target, res);
2902 if (ret > 0 || trailing_dot)
2903 return (ret);
2904 switch (res->res_h_errno) {
2905 case NO_DATA:
2906 case HOST_NOT_FOUND:
2907 break;
2908 case TRY_AGAIN:
2909 if (hp->rcode == SERVFAIL)
2910 break;
2911 /* FALLTHROUGH */
2912 default:
2913 return (-1);
2914 }
2915 saved_herrno = res->res_h_errno;
2916 tried_as_is++;
2917 }
2918
2919 /*
2920 * We do at least one level of search if
2921 * - there is no dot and RES_DEFNAME is set, or
2922 * - there is at least one dot, there is no trailing dot,
2923 * and RES_DNSRCH is set.
2924 */
2925 if ((!dots && (res->options & RES_DEFNAMES)) ||
2926 (dots && !trailing_dot && (res->options & RES_DNSRCH))) {
2927 int done = 0;
2928
2929 for (domain = (const char * const *)res->dnsrch;
2930 *domain && !done;
2931 domain++) {
2932 searched = 1;
2933
2934 if (domain[0][0] == '\0' ||
2935 (domain[0][0] == '.' && domain[0][1] == '\0'))
2936 root_on_list++;
2937
2938 if (root_on_list && tried_as_is)
2939 continue;
2940
2941 ret = res_querydomainN(name, *domain, target, res);
2942 if (ret > 0)
2943 return (ret);
2944 /*
2945 * If no server present, give up.
2946 * If name isn't found in this domain,
2947 * keep trying higher domains in the search list
2948 * (if that's enabled).
2949 * On a NO_DATA error, keep trying, otherwise
2950 * a wildcard entry of another type could keep us
2951 * from finding this entry higher in the domain.
2952 * If we get some other error (negative answer or
2953 * server failure), then stop searching up,
2954 * but try the input name below in case it's
2955 * fully-qualified.
2956 */
2957 switch (res->res_h_errno) {
2958 case NO_DATA:
2959 got_nodata++;
2960 /* FALLTHROUGH */
2961 case HOST_NOT_FOUND:
2962 /* keep trying */
2963 break;
2964 case TRY_AGAIN:
2965 if (hp->rcode == SERVFAIL) {
2966 got_servfail++;
2967 /* try next search element, if any */
2968 break;
2969 }
2970 /* FALLTHROUGH */
2971 default:
2972 /* anything else implies that we're done */
2973 done++;
2974 }
2975 /*
2976 * if we got here for some reason other than DNSRCH,
2977 * we only wanted one iteration of the loop, so stop.
2978 */
2979 if (!(res->options & RES_DNSRCH))
2980 done++;
2981 }
2982 }
2983
2984 switch (res->res_h_errno) {
2985 case NO_DATA:
2986 case HOST_NOT_FOUND:
2987 break;
2988 case TRY_AGAIN:
2989 if (hp->rcode == SERVFAIL)
2990 break;
2991 /* FALLTHROUGH */
2992 default:
2993 goto giveup;
2994 }
2995
2996 /*
2997 * If the query has not already been tried as is then try it
2998 * unless RES_NOTLDQUERY is set and there were no dots.
2999 */
3000 if ((dots || !searched || !(res->options & RES_NOTLDQUERY)) &&
3001 !(tried_as_is || root_on_list)) {
3002 ret = res_querydomainN(name, NULL, target, res);
3003 if (ret > 0)
3004 return (ret);
3005 }
3006
3007 /*
3008 * if we got here, we didn't satisfy the search.
3009 * if we did an initial full query, return that query's h_errno
3010 * (note that we wouldn't be here if that query had succeeded).
3011 * else if we ever got a nodata, send that back as the reason.
3012 * else send back meaningless h_errno, that being the one from
3013 * the last DNSRCH we did.
3014 */
3015 giveup:
3016 if (saved_herrno != -1)
3017 RES_SET_H_ERRNO(res, saved_herrno);
3018 else if (got_nodata)
3019 RES_SET_H_ERRNO(res, NO_DATA);
3020 else if (got_servfail)
3021 RES_SET_H_ERRNO(res, TRY_AGAIN);
3022 return (-1);
3023 }
3024
3025 /*
3026 * Perform a call on res_query on the concatenation of name and domain,
3027 * removing a trailing dot from name if domain is NULL.
3028 */
3029 static int
res_querydomainN(const char * name,const char * domain,struct res_target * target,res_state res)3030 res_querydomainN(const char *name, const char *domain,
3031 struct res_target *target, res_state res)
3032 {
3033 char nbuf[MAXDNAME];
3034 const char *longname = nbuf;
3035 size_t n, d;
3036
3037 #ifdef DEBUG
3038 if (res->options & RES_DEBUG)
3039 printf(";; res_querydomain(%s, %s)\n",
3040 name, domain?domain:"<Nil>");
3041 #endif
3042 if (domain == NULL) {
3043 /*
3044 * Check for trailing '.';
3045 * copy without '.' if present.
3046 */
3047 n = strlen(name);
3048 if (n >= MAXDNAME) {
3049 RES_SET_H_ERRNO(res, NO_RECOVERY);
3050 return (-1);
3051 }
3052 if (n > 0 && name[--n] == '.') {
3053 strncpy(nbuf, name, n);
3054 nbuf[n] = '\0';
3055 } else
3056 longname = name;
3057 } else {
3058 n = strlen(name);
3059 d = strlen(domain);
3060 if (n + d + 1 >= MAXDNAME) {
3061 RES_SET_H_ERRNO(res, NO_RECOVERY);
3062 return (-1);
3063 }
3064 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
3065 }
3066 return (res_queryN(longname, target, res));
3067 }
3068