1 /* $NetBSD: getaddrinfo.c,v 1.109 2015/09/10 14:05:06 christos Exp $ */
2 /* $KAME: getaddrinfo.c,v 1.29 2000/08/31 17:26:57 itojun Exp $ */
3
4 /*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * Issues to be discussed:
35 * - Return values. There are nonstandard return values defined and used
36 * in the source code. This is because RFC2553 is silent about which error
37 * code must be returned for which situation.
38 * - IPv4 classful (shortened) form. RFC2553 is silent about it. XNET 5.2
39 * says to use inet_aton() to convert IPv4 numeric to binary (alows
40 * classful form as a result).
41 * current code - disallow classful form for IPv4 (due to use of inet_pton).
42 * - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is
43 * invalid.
44 * current code - SEGV on freeaddrinfo(NULL)
45 * Note:
46 * - The code filters out AFs that are not supported by the kernel,
47 * when globbing NULL hostname (to loopback, or wildcard). Is it the right
48 * thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG
49 * in ai_flags?
50 * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.
51 * (1) what should we do against numeric hostname (2) what should we do
52 * against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready?
53 * non-loopback address configured? global address configured?
54 */
55
56 #include <sys/cdefs.h>
57 #if defined(LIBC_SCCS) && !defined(lint)
58 __RCSID("$NetBSD: getaddrinfo.c,v 1.109 2015/09/10 14:05:06 christos Exp $");
59 #endif /* LIBC_SCCS and not lint */
60
61 #ifndef RUMP_ACTION
62 #include "namespace.h"
63 #endif
64 #include <sys/types.h>
65 #include <sys/param.h>
66 #include <sys/socket.h>
67 #include <net/if.h>
68 #include <netinet/in.h>
69 #include <arpa/inet.h>
70 #include <arpa/nameser.h>
71 #include <assert.h>
72 #include <ctype.h>
73 #include <errno.h>
74 #include <netdb.h>
75 #include <resolv.h>
76 #include <stddef.h>
77 #include <stdio.h>
78 #include <stdlib.h>
79 #include <string.h>
80 #include <unistd.h>
81 #include <ifaddrs.h>
82
83 #include <syslog.h>
84 #include <stdarg.h>
85 #include <nsswitch.h>
86
87 #ifdef YP
88 #include <rpc/rpc.h>
89 #include <rpcsvc/yp_prot.h>
90 #include <rpcsvc/ypclnt.h>
91 #endif
92
93 #include "servent.h"
94
95 #ifndef RUMP_ACTION
96 #ifdef __weak_alias
97 __weak_alias(getaddrinfo,_getaddrinfo)
98 __weak_alias(allocaddrinfo,_allocaddrinfo)
99 __weak_alias(freeaddrinfo,_freeaddrinfo)
100 __weak_alias(gai_strerror,_gai_strerror)
101 #endif
102 #endif
103
104 #define SUCCESS 0
105 #define ANY 0
106 #define YES 1
107 #define NO 0
108
109 static const char in_addrany[] = { 0, 0, 0, 0 };
110 static const char in_loopback[] = { 127, 0, 0, 1 };
111 #ifdef INET6
112 static const char in6_addrany[] = {
113 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
114 };
115 static const char in6_loopback[] = {
116 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
117 };
118 #endif
119
120 static const struct afd {
121 int a_af;
122 int a_addrlen;
123 int a_socklen;
124 int a_off;
125 const char *a_addrany;
126 const char *a_loopback;
127 int a_scoped;
128 } afdl [] = {
129 #ifdef INET6
130 {PF_INET6, sizeof(struct in6_addr),
131 sizeof(struct sockaddr_in6),
132 offsetof(struct sockaddr_in6, sin6_addr),
133 in6_addrany, in6_loopback, 1},
134 #endif
135 {PF_INET, sizeof(struct in_addr),
136 sizeof(struct sockaddr_in),
137 offsetof(struct sockaddr_in, sin_addr),
138 in_addrany, in_loopback, 0},
139 {0, 0, 0, 0, NULL, NULL, 0},
140 };
141
142 struct explore {
143 int e_af;
144 int e_socktype;
145 int e_protocol;
146 const char *e_protostr;
147 int e_wild;
148 #define WILD_AF(ex) ((ex)->e_wild & 0x01)
149 #define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02)
150 #define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04)
151 };
152
153 static const struct explore explore[] = {
154 #if 0
155 { PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
156 #endif
157 #ifdef INET6
158 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
159 { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
160 { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 },
161 #endif
162 { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
163 { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
164 { PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
165 { PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
166 { PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
167 { PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 },
168 { -1, 0, 0, NULL, 0 },
169 };
170
171 #ifdef INET6
172 #define PTON_MAX 16
173 #else
174 #define PTON_MAX 4
175 #endif
176
177 static const ns_src default_dns_files[] = {
178 { NSSRC_FILES, NS_SUCCESS },
179 { NSSRC_DNS, NS_SUCCESS },
180 { 0, 0 }
181 };
182
183 #define MAXPACKET (64*1024)
184
185 typedef union {
186 HEADER hdr;
187 u_char buf[MAXPACKET];
188 } querybuf;
189
190 struct res_target {
191 struct res_target *next;
192 const char *name; /* domain name */
193 int qclass, qtype; /* class and type of query */
194 u_char *answer; /* buffer to put answer */
195 int anslen; /* size of answer buffer */
196 int n; /* result length */
197 };
198
199 struct srvinfo {
200 struct srvinfo *next;
201 char name[MAXDNAME];
202 int port, pri, weight;
203 };
204
205 static int gai_srvok(const char *);
206 static int str2number(const char *);
207 static int explore_fqdn(const struct addrinfo *, const char *,
208 const char *, struct addrinfo **, struct servent_data *);
209 static int explore_null(const struct addrinfo *,
210 const char *, struct addrinfo **, struct servent_data *);
211 static int explore_numeric(const struct addrinfo *, const char *,
212 const char *, struct addrinfo **, const char *, struct servent_data *);
213 static int explore_numeric_scope(const struct addrinfo *, const char *,
214 const char *, struct addrinfo **, struct servent_data *);
215 static int get_canonname(const struct addrinfo *,
216 struct addrinfo *, const char *);
217 static struct addrinfo *get_ai(const struct addrinfo *,
218 const struct afd *, const char *);
219 static int get_portmatch(const struct addrinfo *, const char *,
220 struct servent_data *);
221 static int get_port(const struct addrinfo *, const char *, int,
222 struct servent_data *);
223 static const struct afd *find_afd(int);
224 static int addrconfig(uint64_t *);
225 #ifdef INET6
226 static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *);
227 #endif
228
229 static struct addrinfo *getanswer(const querybuf *, int, const char *, int,
230 const struct addrinfo *);
231 static void aisort(struct addrinfo *s, res_state res);
232 static struct addrinfo * _dns_query(struct res_target *,
233 const struct addrinfo *, res_state, int);
234 static struct addrinfo * _dns_srv_lookup(const char *, const char *,
235 const struct addrinfo *);
236 static struct addrinfo * _dns_host_lookup(const char *,
237 const struct addrinfo *);
238 static int _dns_getaddrinfo(void *, void *, va_list);
239 static void _sethtent(FILE **);
240 static void _endhtent(FILE **);
241 static struct addrinfo *_gethtent(FILE **, const char *,
242 const struct addrinfo *);
243 static int _files_getaddrinfo(void *, void *, va_list);
244 #ifdef YP
245 static struct addrinfo *_yphostent(char *, const struct addrinfo *);
246 static int _yp_getaddrinfo(void *, void *, va_list);
247 #endif
248
249 static int res_queryN(const char *, struct res_target *, res_state);
250 static int res_searchN(const char *, struct res_target *, res_state);
251 static int res_querydomainN(const char *, const char *,
252 struct res_target *, res_state);
253
254 static const char * const ai_errlist[] = {
255 "Success",
256 "Address family for hostname not supported", /* EAI_ADDRFAMILY */
257 "Temporary failure in name resolution", /* EAI_AGAIN */
258 "Invalid value for ai_flags", /* EAI_BADFLAGS */
259 "Non-recoverable failure in name resolution", /* EAI_FAIL */
260 "ai_family not supported", /* EAI_FAMILY */
261 "Memory allocation failure", /* EAI_MEMORY */
262 "No address associated with hostname", /* EAI_NODATA */
263 "hostname nor servname provided, or not known", /* EAI_NONAME */
264 "servname not supported for ai_socktype", /* EAI_SERVICE */
265 "ai_socktype not supported", /* EAI_SOCKTYPE */
266 "System error returned in errno", /* EAI_SYSTEM */
267 "Invalid value for hints", /* EAI_BADHINTS */
268 "Resolved protocol is unknown", /* EAI_PROTOCOL */
269 "Argument buffer overflow", /* EAI_OVERFLOW */
270 "Unknown error", /* EAI_MAX */
271 };
272
273 /* XXX macros that make external reference is BAD. */
274
275 #define GET_AI(ai, afd, addr) \
276 do { \
277 /* external reference: pai, error, and label free */ \
278 (ai) = get_ai(pai, (afd), (addr)); \
279 if ((ai) == NULL) { \
280 error = EAI_MEMORY; \
281 goto free; \
282 } \
283 } while (/*CONSTCOND*/0)
284
285 #define GET_PORT(ai, serv, svd) \
286 do { \
287 /* external reference: error and label free */ \
288 error = get_port((ai), (serv), 0, (svd)); \
289 if (error != 0) \
290 goto free; \
291 } while (/*CONSTCOND*/0)
292
293 #define GET_CANONNAME(ai, str) \
294 do { \
295 /* external reference: pai, error and label free */ \
296 error = get_canonname(pai, (ai), (str)); \
297 if (error != 0) \
298 goto free; \
299 } while (/*CONSTCOND*/0)
300
301 #define ERR(err) \
302 do { \
303 /* external reference: error, and label bad */ \
304 error = (err); \
305 goto bad; \
306 /*NOTREACHED*/ \
307 } while (/*CONSTCOND*/0)
308
309 #define MATCH_FAMILY(x, y, w) \
310 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || \
311 (y) == PF_UNSPEC)))
312 #define MATCH(x, y, w) \
313 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
314
315 const char *
gai_strerror(int ecode)316 gai_strerror(int ecode)
317 {
318 if (ecode < 0 || ecode > EAI_MAX)
319 ecode = EAI_MAX;
320 return ai_errlist[ecode];
321 }
322
323 void
freeaddrinfo(struct addrinfo * ai)324 freeaddrinfo(struct addrinfo *ai)
325 {
326 struct addrinfo *next;
327
328 _DIAGASSERT(ai != NULL);
329
330 do {
331 next = ai->ai_next;
332 if (ai->ai_canonname)
333 free(ai->ai_canonname);
334 /* no need to free(ai->ai_addr) */
335 free(ai);
336 ai = next;
337 } while (ai);
338 }
339
340 /*
341 * We don't want localization to affect us
342 */
343 #define PERIOD '.'
344 #define hyphenchar(c) ((c) == '-')
345 #define periodchar(c) ((c) == PERIOD)
346 #define underschar(c) ((c) == '_')
347 #define alphachar(c) (((c) >= 'a' && (c) <= 'z') || ((c) >= 'A' && (c) <= 'Z'))
348 #define digitchar(c) ((c) >= '0' && (c) <= '9')
349
350 #define firstchar(c) (alphachar(c) || digitchar(c) || underschar(c))
351 #define lastchar(c) (alphachar(c) || digitchar(c))
352 #define middlechar(c) (lastchar(c) || hyphenchar(c))
353
354 static int
gai_srvok(const char * dn)355 gai_srvok(const char *dn)
356 {
357 int nch, pch, ch;
358
359 for (pch = PERIOD, nch = ch = *dn++; ch != '\0'; pch = ch, ch = nch) {
360 if (periodchar(ch))
361 continue;
362 if (periodchar(pch)) {
363 if (!firstchar(ch))
364 return 0;
365 } else if (periodchar(nch) || nch == '\0') {
366 if (!lastchar(ch))
367 return 0;
368 } else if (!middlechar(ch))
369 return 0;
370 }
371 return 1;
372 }
373
374 static in_port_t *
getport(struct addrinfo * ai)375 getport(struct addrinfo *ai) {
376 static in_port_t p;
377
378 switch (ai->ai_family) {
379 case AF_INET:
380 return &((struct sockaddr_in *)(void *)ai->ai_addr)->sin_port;
381 #ifdef INET6
382 case AF_INET6:
383 return &((struct sockaddr_in6 *)(void *)ai->ai_addr)->sin6_port;
384 #endif
385 default:
386 p = 0;
387 /* XXX: abort()? */
388 return &p;
389 }
390 }
391
392 static int
str2number(const char * p)393 str2number(const char *p)
394 {
395 char *ep;
396 unsigned long v;
397
398 _DIAGASSERT(p != NULL);
399
400 if (*p == '\0')
401 return -1;
402 ep = NULL;
403 errno = 0;
404 v = strtoul(p, &ep, 10);
405 if (errno == 0 && ep && *ep == '\0' && v <= INT_MAX)
406 return (int)v;
407 else
408 return -1;
409 }
410
411 int
getaddrinfo(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res)412 getaddrinfo(const char *hostname, const char *servname,
413 const struct addrinfo *hints, struct addrinfo **res)
414 {
415 struct addrinfo sentinel;
416 struct addrinfo *cur;
417 int error = 0;
418 struct addrinfo ai;
419 struct addrinfo ai0;
420 struct addrinfo *pai;
421 const struct explore *ex;
422 struct servent_data svd;
423 uint64_t mask = (uint64_t)~0ULL;
424
425 /* hostname is allowed to be NULL */
426 /* servname is allowed to be NULL */
427 /* hints is allowed to be NULL */
428 _DIAGASSERT(res != NULL);
429
430 (void)memset(&svd, 0, sizeof(svd));
431 memset(&sentinel, 0, sizeof(sentinel));
432 cur = &sentinel;
433 memset(&ai, 0, sizeof(ai));
434 pai = &ai;
435 pai->ai_flags = 0;
436 pai->ai_family = PF_UNSPEC;
437 pai->ai_socktype = ANY;
438 pai->ai_protocol = ANY;
439 pai->ai_addrlen = 0;
440 pai->ai_canonname = NULL;
441 pai->ai_addr = NULL;
442 pai->ai_next = NULL;
443
444 if (hostname == NULL && servname == NULL)
445 return EAI_NONAME;
446 if (hints) {
447 /* error check for hints */
448 if (hints->ai_addrlen || hints->ai_canonname ||
449 hints->ai_addr || hints->ai_next)
450 ERR(EAI_BADHINTS); /* xxx */
451 if (hints->ai_flags & ~AI_MASK)
452 ERR(EAI_BADFLAGS);
453 switch (hints->ai_family) {
454 case PF_UNSPEC:
455 case PF_INET:
456 #ifdef INET6
457 case PF_INET6:
458 #endif
459 break;
460 default:
461 ERR(EAI_FAMILY);
462 }
463 memcpy(pai, hints, sizeof(*pai));
464
465 /*
466 * if both socktype/protocol are specified, check if they
467 * are meaningful combination.
468 */
469 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
470 for (ex = explore; ex->e_af >= 0; ex++) {
471 if (pai->ai_family != ex->e_af)
472 continue;
473 if (ex->e_socktype == ANY)
474 continue;
475 if (ex->e_protocol == ANY)
476 continue;
477 if (pai->ai_socktype == ex->e_socktype
478 && pai->ai_protocol != ex->e_protocol) {
479 ERR(EAI_BADHINTS);
480 }
481 }
482 }
483 }
484
485 if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && addrconfig(&mask) == -1)
486 ERR(EAI_FAIL);
487
488 /*
489 * check for special cases. (1) numeric servname is disallowed if
490 * socktype/protocol are left unspecified. (2) servname is disallowed
491 * for raw and other inet{,6} sockets.
492 */
493 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
494 #ifdef PF_INET6
495 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
496 #endif
497 ) {
498 ai0 = *pai; /* backup *pai */
499
500 if (pai->ai_family == PF_UNSPEC) {
501 #ifdef PF_INET6
502 pai->ai_family = PF_INET6;
503 #else
504 pai->ai_family = PF_INET;
505 #endif
506 }
507 error = get_portmatch(pai, servname, &svd);
508 if (error)
509 goto bad;
510
511 *pai = ai0;
512 }
513
514 ai0 = *pai;
515
516 /* NULL hostname, or numeric hostname */
517 for (ex = explore; ex->e_af >= 0; ex++) {
518 *pai = ai0;
519
520 /* ADDRCONFIG check */
521 if ((((uint64_t)1 << ex->e_af) & mask) == 0)
522 continue;
523
524 /* PF_UNSPEC entries are prepared for DNS queries only */
525 if (ex->e_af == PF_UNSPEC)
526 continue;
527
528 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
529 continue;
530 if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
531 continue;
532 if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
533 continue;
534 if (pai->ai_family == PF_UNSPEC)
535 pai->ai_family = ex->e_af;
536 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
537 pai->ai_socktype = ex->e_socktype;
538 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
539 pai->ai_protocol = ex->e_protocol;
540
541 if (hostname == NULL)
542 error = explore_null(pai, servname, &cur->ai_next,
543 &svd);
544 else
545 error = explore_numeric_scope(pai, hostname, servname,
546 &cur->ai_next, &svd);
547
548 if (error)
549 goto free;
550
551 while (cur->ai_next)
552 cur = cur->ai_next;
553 }
554
555 /*
556 * XXX
557 * If numeric representation of AF1 can be interpreted as FQDN
558 * representation of AF2, we need to think again about the code below.
559 */
560 if (sentinel.ai_next)
561 goto good;
562
563 if (hostname == NULL)
564 ERR(EAI_NODATA);
565 if (pai->ai_flags & AI_NUMERICHOST)
566 ERR(EAI_NONAME);
567
568 /*
569 * hostname as alphabetical name.
570 * we would like to prefer AF_INET6 than AF_INET, so we'll make a
571 * outer loop by AFs.
572 */
573 for (ex = explore; ex->e_af >= 0; ex++) {
574 *pai = ai0;
575
576
577 /* ADDRCONFIG check */
578 /* PF_UNSPEC entries are prepared for DNS queries only */
579 if (ex->e_af != PF_UNSPEC &&
580 (((uint64_t)1 << ex->e_af) & mask) == 0)
581 continue;
582
583 /* require exact match for family field */
584 if (pai->ai_family != ex->e_af)
585 continue;
586
587 if (!MATCH(pai->ai_socktype, ex->e_socktype,
588 WILD_SOCKTYPE(ex))) {
589 continue;
590 }
591 if (!MATCH(pai->ai_protocol, ex->e_protocol,
592 WILD_PROTOCOL(ex))) {
593 continue;
594 }
595
596 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
597 pai->ai_socktype = ex->e_socktype;
598 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
599 pai->ai_protocol = ex->e_protocol;
600
601 error = explore_fqdn(pai, hostname, servname, &cur->ai_next,
602 &svd);
603
604 while (cur && cur->ai_next)
605 cur = cur->ai_next;
606 }
607
608 /* XXX */
609 if (sentinel.ai_next)
610 error = 0;
611
612 if (error)
613 goto free;
614
615 if (sentinel.ai_next) {
616 good:
617 endservent_r(&svd);
618 *res = sentinel.ai_next;
619 return SUCCESS;
620 } else
621 error = EAI_FAIL;
622 free:
623 bad:
624 endservent_r(&svd);
625 if (sentinel.ai_next)
626 freeaddrinfo(sentinel.ai_next);
627 *res = NULL;
628 return error;
629 }
630
631 /*
632 * FQDN hostname, DNS lookup
633 */
634 static int
explore_fqdn(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,struct servent_data * svd)635 explore_fqdn(const struct addrinfo *pai, const char *hostname,
636 const char *servname, struct addrinfo **res, struct servent_data *svd)
637 {
638 struct addrinfo *result;
639 struct addrinfo *cur;
640 int error = 0;
641 static const ns_dtab dtab[] = {
642 NS_FILES_CB(_files_getaddrinfo, NULL)
643 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
644 NS_NIS_CB(_yp_getaddrinfo, NULL)
645 NS_NULL_CB
646 };
647
648 _DIAGASSERT(pai != NULL);
649 /* hostname may be NULL */
650 /* servname may be NULL */
651 _DIAGASSERT(res != NULL);
652
653 result = NULL;
654
655 /*
656 * if the servname does not match socktype/protocol, ignore it.
657 */
658 if (get_portmatch(pai, servname, svd) != 0)
659 return 0;
660
661 switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
662 default_dns_files, hostname, pai, servname)) {
663 case NS_TRYAGAIN:
664 error = EAI_AGAIN;
665 goto free;
666 case NS_UNAVAIL:
667 error = EAI_FAIL;
668 goto free;
669 case NS_NOTFOUND:
670 error = EAI_NODATA;
671 goto free;
672 case NS_SUCCESS:
673 error = 0;
674 for (cur = result; cur; cur = cur->ai_next) {
675 /* Check for already filled port. */
676 if (*getport(cur))
677 continue;
678 GET_PORT(cur, servname, svd);
679 /* canonname should be filled already */
680 }
681 break;
682 }
683
684 *res = result;
685
686 return 0;
687
688 free:
689 if (result)
690 freeaddrinfo(result);
691 return error;
692 }
693
694 /*
695 * hostname == NULL.
696 * passive socket -> anyaddr (0.0.0.0 or ::)
697 * non-passive socket -> localhost (127.0.0.1 or ::1)
698 */
699 static int
explore_null(const struct addrinfo * pai,const char * servname,struct addrinfo ** res,struct servent_data * svd)700 explore_null(const struct addrinfo *pai, const char *servname,
701 struct addrinfo **res, struct servent_data *svd)
702 {
703 int s;
704 const struct afd *afd;
705 struct addrinfo *cur;
706 struct addrinfo sentinel;
707 int error;
708
709 _DIAGASSERT(pai != NULL);
710 /* servname may be NULL */
711 _DIAGASSERT(res != NULL);
712
713 *res = NULL;
714 sentinel.ai_next = NULL;
715 cur = &sentinel;
716
717 /*
718 * filter out AFs that are not supported by the kernel
719 * XXX errno?
720 */
721 s = socket(pai->ai_family, SOCK_DGRAM, 0);
722 if (s < 0) {
723 if (errno != EMFILE)
724 return 0;
725 } else
726 close(s);
727
728 /*
729 * if the servname does not match socktype/protocol, ignore it.
730 */
731 if (get_portmatch(pai, servname, svd) != 0)
732 return 0;
733
734 afd = find_afd(pai->ai_family);
735 if (afd == NULL)
736 return 0;
737
738 if (pai->ai_flags & AI_PASSIVE) {
739 GET_AI(cur->ai_next, afd, afd->a_addrany);
740 /* xxx meaningless?
741 * GET_CANONNAME(cur->ai_next, "anyaddr");
742 */
743 GET_PORT(cur->ai_next, servname, svd);
744 } else {
745 GET_AI(cur->ai_next, afd, afd->a_loopback);
746 /* xxx meaningless?
747 * GET_CANONNAME(cur->ai_next, "localhost");
748 */
749 GET_PORT(cur->ai_next, servname, svd);
750 }
751 cur = cur->ai_next;
752
753 *res = sentinel.ai_next;
754 return 0;
755
756 free:
757 if (sentinel.ai_next)
758 freeaddrinfo(sentinel.ai_next);
759 return error;
760 }
761
762 /*
763 * numeric hostname
764 */
765 static int
explore_numeric(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,const char * canonname,struct servent_data * svd)766 explore_numeric(const struct addrinfo *pai, const char *hostname,
767 const char *servname, struct addrinfo **res, const char *canonname,
768 struct servent_data *svd)
769 {
770 const struct afd *afd;
771 struct addrinfo *cur;
772 struct addrinfo sentinel;
773 int error;
774 char pton[PTON_MAX];
775
776 _DIAGASSERT(pai != NULL);
777 /* hostname may be NULL */
778 /* servname may be NULL */
779 _DIAGASSERT(res != NULL);
780
781 *res = NULL;
782 sentinel.ai_next = NULL;
783 cur = &sentinel;
784
785 /*
786 * if the servname does not match socktype/protocol, ignore it.
787 */
788 if (get_portmatch(pai, servname, svd) != 0)
789 return 0;
790
791 afd = find_afd(pai->ai_family);
792 if (afd == NULL)
793 return 0;
794
795 switch (afd->a_af) {
796 #if 0 /*X/Open spec*/
797 case AF_INET:
798 if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
799 if (pai->ai_family == afd->a_af ||
800 pai->ai_family == PF_UNSPEC /*?*/) {
801 GET_AI(cur->ai_next, afd, pton);
802 GET_PORT(cur->ai_next, servname, svd);
803 if ((pai->ai_flags & AI_CANONNAME)) {
804 /*
805 * Set the numeric address itself as
806 * the canonical name, based on a
807 * clarification in rfc2553bis-03.
808 */
809 GET_CANONNAME(cur->ai_next, canonname);
810 }
811 while (cur && cur->ai_next)
812 cur = cur->ai_next;
813 } else
814 ERR(EAI_FAMILY); /*xxx*/
815 }
816 break;
817 #endif
818 default:
819 if (inet_pton(afd->a_af, hostname, pton) == 1) {
820 if (pai->ai_family == afd->a_af ||
821 pai->ai_family == PF_UNSPEC /*?*/) {
822 GET_AI(cur->ai_next, afd, pton);
823 GET_PORT(cur->ai_next, servname, svd);
824 if ((pai->ai_flags & AI_CANONNAME)) {
825 /*
826 * Set the numeric address itself as
827 * the canonical name, based on a
828 * clarification in rfc2553bis-03.
829 */
830 GET_CANONNAME(cur->ai_next, canonname);
831 }
832 while (cur->ai_next)
833 cur = cur->ai_next;
834 } else
835 ERR(EAI_FAMILY); /*xxx*/
836 }
837 break;
838 }
839
840 *res = sentinel.ai_next;
841 return 0;
842
843 free:
844 bad:
845 if (sentinel.ai_next)
846 freeaddrinfo(sentinel.ai_next);
847 return error;
848 }
849
850 /*
851 * numeric hostname with scope
852 */
853 static int
explore_numeric_scope(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,struct servent_data * svd)854 explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
855 const char *servname, struct addrinfo **res, struct servent_data *svd)
856 {
857 #if !defined(SCOPE_DELIMITER) || !defined(INET6)
858 return explore_numeric(pai, hostname, servname, res, hostname, svd);
859 #else
860 const struct afd *afd;
861 struct addrinfo *cur;
862 int error;
863 char *cp, *hostname2 = NULL, *scope, *addr;
864 struct sockaddr_in6 *sin6;
865
866 _DIAGASSERT(pai != NULL);
867 /* hostname may be NULL */
868 /* servname may be NULL */
869 _DIAGASSERT(res != NULL);
870
871 /*
872 * if the servname does not match socktype/protocol, ignore it.
873 */
874 if (get_portmatch(pai, servname, svd) != 0)
875 return 0;
876
877 afd = find_afd(pai->ai_family);
878 if (afd == NULL)
879 return 0;
880
881 if (!afd->a_scoped)
882 return explore_numeric(pai, hostname, servname, res, hostname,
883 svd);
884
885 cp = strchr(hostname, SCOPE_DELIMITER);
886 if (cp == NULL)
887 return explore_numeric(pai, hostname, servname, res, hostname,
888 svd);
889
890 /*
891 * Handle special case of <scoped_address><delimiter><scope id>
892 */
893 hostname2 = strdup(hostname);
894 if (hostname2 == NULL)
895 return EAI_MEMORY;
896 /* terminate at the delimiter */
897 hostname2[cp - hostname] = '\0';
898 addr = hostname2;
899 scope = cp + 1;
900
901 error = explore_numeric(pai, addr, servname, res, hostname, svd);
902 if (error == 0) {
903 u_int32_t scopeid;
904
905 for (cur = *res; cur; cur = cur->ai_next) {
906 if (cur->ai_family != AF_INET6)
907 continue;
908 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
909 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
910 free(hostname2);
911 return(EAI_NODATA); /* XXX: is return OK? */
912 }
913 sin6->sin6_scope_id = scopeid;
914 }
915 }
916
917 free(hostname2);
918
919 return error;
920 #endif
921 }
922
923 static int
get_canonname(const struct addrinfo * pai,struct addrinfo * ai,const char * str)924 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
925 {
926
927 _DIAGASSERT(pai != NULL);
928 _DIAGASSERT(ai != NULL);
929 _DIAGASSERT(str != NULL);
930
931 if ((pai->ai_flags & AI_CANONNAME) != 0) {
932 ai->ai_canonname = strdup(str);
933 if (ai->ai_canonname == NULL)
934 return EAI_MEMORY;
935 }
936 return 0;
937 }
938
939 struct addrinfo *
allocaddrinfo(socklen_t addrlen)940 allocaddrinfo(socklen_t addrlen)
941 {
942 struct addrinfo *ai;
943
944 ai = calloc(sizeof(struct addrinfo) + addrlen, 1);
945 if (ai) {
946 ai->ai_addr = (void *)(ai+1);
947 ai->ai_addrlen = ai->ai_addr->sa_len = addrlen;
948 }
949
950 return ai;
951 }
952
953 static struct addrinfo *
get_ai(const struct addrinfo * pai,const struct afd * afd,const char * addr)954 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
955 {
956 char *p;
957 struct addrinfo *ai;
958 struct sockaddr *save;
959
960 _DIAGASSERT(pai != NULL);
961 _DIAGASSERT(afd != NULL);
962 _DIAGASSERT(addr != NULL);
963
964 ai = allocaddrinfo((socklen_t)afd->a_socklen);
965 if (ai == NULL)
966 return NULL;
967
968 save = ai->ai_addr;
969 memcpy(ai, pai, sizeof(struct addrinfo));
970
971 /* since we just overwrote all of ai, we have
972 to restore ai_addr and ai_addrlen */
973 ai->ai_addr = save;
974 ai->ai_addrlen = (socklen_t)afd->a_socklen;
975
976 ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
977 p = (char *)(void *)(ai->ai_addr);
978 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
979 return ai;
980 }
981
982 static int
get_portmatch(const struct addrinfo * ai,const char * servname,struct servent_data * svd)983 get_portmatch(const struct addrinfo *ai, const char *servname,
984 struct servent_data *svd)
985 {
986
987 _DIAGASSERT(ai != NULL);
988 /* servname may be NULL */
989
990 return get_port(ai, servname, 1, svd);
991 }
992
993 static int
get_port(const struct addrinfo * ai,const char * servname,int matchonly,struct servent_data * svd)994 get_port(const struct addrinfo *ai, const char *servname, int matchonly,
995 struct servent_data *svd)
996 {
997 const char *proto;
998 struct servent *sp;
999 int port;
1000 int allownumeric;
1001
1002 _DIAGASSERT(ai != NULL);
1003 /* servname may be NULL */
1004
1005 if (servname == NULL)
1006 return 0;
1007 switch (ai->ai_family) {
1008 case AF_INET:
1009 #ifdef AF_INET6
1010 case AF_INET6:
1011 #endif
1012 break;
1013 default:
1014 return 0;
1015 }
1016
1017 switch (ai->ai_socktype) {
1018 case SOCK_RAW:
1019 return EAI_SERVICE;
1020 case SOCK_DGRAM:
1021 case SOCK_STREAM:
1022 allownumeric = 1;
1023 break;
1024 case ANY:
1025 /*
1026 * This was 0. It is now 1 so that queries specifying
1027 * a NULL hint, or hint without socktype (but, hopefully,
1028 * with protocol) and numeric address actually work.
1029 */
1030 allownumeric = 1;
1031 break;
1032 default:
1033 return EAI_SOCKTYPE;
1034 }
1035
1036 port = str2number(servname);
1037 if (port >= 0) {
1038 if (!allownumeric)
1039 return EAI_SERVICE;
1040 if (port < 0 || port > 65535)
1041 return EAI_SERVICE;
1042 port = htons(port);
1043 } else {
1044 struct servent sv;
1045 if (ai->ai_flags & AI_NUMERICSERV)
1046 return EAI_NONAME;
1047
1048 switch (ai->ai_socktype) {
1049 case SOCK_DGRAM:
1050 proto = "udp";
1051 break;
1052 case SOCK_STREAM:
1053 proto = "tcp";
1054 break;
1055 default:
1056 proto = NULL;
1057 break;
1058 }
1059
1060 sp = getservbyname_r(servname, proto, &sv, svd);
1061 if (sp == NULL)
1062 return EAI_SERVICE;
1063 port = sp->s_port;
1064 }
1065
1066 if (!matchonly)
1067 *getport(__UNCONST(ai)) = port;
1068 return 0;
1069 }
1070
1071 static const struct afd *
find_afd(int af)1072 find_afd(int af)
1073 {
1074 const struct afd *afd;
1075
1076 if (af == PF_UNSPEC)
1077 return NULL;
1078 for (afd = afdl; afd->a_af; afd++) {
1079 if (afd->a_af == af)
1080 return afd;
1081 }
1082 return NULL;
1083 }
1084
1085 /*
1086 * AI_ADDRCONFIG check: Build a mask containing a bit set for each address
1087 * family configured in the system.
1088 *
1089 */
1090 static int
addrconfig(uint64_t * mask)1091 addrconfig(uint64_t *mask)
1092 {
1093 struct ifaddrs *ifaddrs, *ifa;
1094
1095 if (getifaddrs(&ifaddrs) == -1)
1096 return -1;
1097
1098 *mask = 0;
1099 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next)
1100 if (ifa->ifa_addr && (ifa->ifa_flags & IFF_UP)) {
1101 _DIAGASSERT(ifa->ifa_addr->sa_family < 64);
1102 *mask |= (uint64_t)1 << ifa->ifa_addr->sa_family;
1103 }
1104
1105 freeifaddrs(ifaddrs);
1106 return 0;
1107 }
1108
1109 #ifdef INET6
1110 /* convert a string to a scope identifier. XXX: IPv6 specific */
1111 static int
ip6_str2scopeid(char * scope,struct sockaddr_in6 * sin6,u_int32_t * scopeid)1112 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
1113 {
1114 u_long lscopeid;
1115 struct in6_addr *a6;
1116 char *ep;
1117
1118 _DIAGASSERT(scope != NULL);
1119 _DIAGASSERT(sin6 != NULL);
1120 _DIAGASSERT(scopeid != NULL);
1121
1122 a6 = &sin6->sin6_addr;
1123
1124 /* empty scopeid portion is invalid */
1125 if (*scope == '\0')
1126 return -1;
1127
1128 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
1129 /*
1130 * We currently assume a one-to-one mapping between links
1131 * and interfaces, so we simply use interface indices for
1132 * like-local scopes.
1133 */
1134 *scopeid = if_nametoindex(scope);
1135 if (*scopeid == 0)
1136 goto trynumeric;
1137 return 0;
1138 }
1139
1140 /* still unclear about literal, allow numeric only - placeholder */
1141 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1142 goto trynumeric;
1143 if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1144 goto trynumeric;
1145 else
1146 goto trynumeric; /* global */
1147
1148 /* try to convert to a numeric id as a last resort */
1149 trynumeric:
1150 errno = 0;
1151 lscopeid = strtoul(scope, &ep, 10);
1152 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
1153 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
1154 return 0;
1155 else
1156 return -1;
1157 }
1158 #endif
1159
1160 /* code duplicate with gethnamaddr.c */
1161
1162 static const char AskedForGot[] =
1163 "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1164
1165 static struct addrinfo *
getanswer(const querybuf * answer,int anslen,const char * qname,int qtype,const struct addrinfo * pai)1166 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
1167 const struct addrinfo *pai)
1168 {
1169 struct addrinfo sentinel, *cur;
1170 struct addrinfo ai, *aip;
1171 const struct afd *afd;
1172 char *canonname;
1173 const HEADER *hp;
1174 const u_char *cp;
1175 int n;
1176 const u_char *eom;
1177 char *bp, *ep;
1178 int type, class, ancount, qdcount;
1179 int haveanswer, had_error;
1180 char tbuf[MAXDNAME];
1181 int (*name_ok) (const char *);
1182 char hostbuf[8*1024];
1183 int port, pri, weight;
1184 struct srvinfo *srvlist, *srv, *csrv;
1185
1186 _DIAGASSERT(answer != NULL);
1187 _DIAGASSERT(qname != NULL);
1188 _DIAGASSERT(pai != NULL);
1189
1190 memset(&sentinel, 0, sizeof(sentinel));
1191 cur = &sentinel;
1192
1193 canonname = NULL;
1194 eom = answer->buf + anslen;
1195 switch (qtype) {
1196 case T_A:
1197 case T_AAAA:
1198 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
1199 name_ok = res_hnok;
1200 break;
1201 case T_SRV:
1202 name_ok = gai_srvok;
1203 break;
1204 default:
1205 return NULL; /* XXX should be abort(); */
1206 }
1207 /*
1208 * find first satisfactory answer
1209 */
1210 hp = &answer->hdr;
1211 ancount = ntohs(hp->ancount);
1212 qdcount = ntohs(hp->qdcount);
1213 bp = hostbuf;
1214 ep = hostbuf + sizeof hostbuf;
1215 cp = answer->buf + HFIXEDSZ;
1216 if (qdcount != 1) {
1217 h_errno = NO_RECOVERY;
1218 return (NULL);
1219 }
1220 n = dn_expand(answer->buf, eom, cp, bp, (int)(ep - bp));
1221 if ((n < 0) || !(*name_ok)(bp)) {
1222 h_errno = NO_RECOVERY;
1223 return (NULL);
1224 }
1225 cp += n + QFIXEDSZ;
1226 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
1227 /* res_send() has already verified that the query name is the
1228 * same as the one we sent; this just gets the expanded name
1229 * (i.e., with the succeeding search-domain tacked on).
1230 */
1231 n = (int)strlen(bp) + 1; /* for the \0 */
1232 if (n >= MAXHOSTNAMELEN) {
1233 h_errno = NO_RECOVERY;
1234 return (NULL);
1235 }
1236 canonname = bp;
1237 bp += n;
1238 /* The qname can be abbreviated, but h_name is now absolute. */
1239 qname = canonname;
1240 }
1241 haveanswer = 0;
1242 had_error = 0;
1243 srvlist = NULL;
1244 while (ancount-- > 0 && cp < eom && !had_error) {
1245 n = dn_expand(answer->buf, eom, cp, bp, (int)(ep - bp));
1246 if ((n < 0) || !(*name_ok)(bp)) {
1247 had_error++;
1248 continue;
1249 }
1250 cp += n; /* name */
1251 type = _getshort(cp);
1252 cp += INT16SZ; /* type */
1253 class = _getshort(cp);
1254 cp += INT16SZ + INT32SZ; /* class, TTL */
1255 n = _getshort(cp);
1256 cp += INT16SZ; /* len */
1257 if (class != C_IN) {
1258 /* XXX - debug? syslog? */
1259 cp += n;
1260 continue; /* XXX - had_error++ ? */
1261 }
1262 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
1263 type == T_CNAME) {
1264 n = dn_expand(answer->buf, eom, cp, tbuf, (int)sizeof tbuf);
1265 if ((n < 0) || !(*name_ok)(tbuf)) {
1266 had_error++;
1267 continue;
1268 }
1269 cp += n;
1270 /* Get canonical name. */
1271 n = (int)strlen(tbuf) + 1; /* for the \0 */
1272 if (n > ep - bp || n >= MAXHOSTNAMELEN) {
1273 had_error++;
1274 continue;
1275 }
1276 strlcpy(bp, tbuf, (size_t)(ep - bp));
1277 canonname = bp;
1278 bp += n;
1279 continue;
1280 }
1281 if (qtype == T_ANY) {
1282 if (!(type == T_A || type == T_AAAA)) {
1283 cp += n;
1284 continue;
1285 }
1286 } else if (type != qtype) {
1287 if (type != T_KEY && type != T_SIG) {
1288 struct syslog_data sd = SYSLOG_DATA_INIT;
1289 syslog_r(LOG_NOTICE|LOG_AUTH, &sd,
1290 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
1291 qname, p_class(C_IN), p_type(qtype),
1292 p_type(type));
1293 }
1294 cp += n;
1295 continue; /* XXX - had_error++ ? */
1296 }
1297 switch (type) {
1298 case T_A:
1299 case T_AAAA:
1300 if (strcasecmp(canonname, bp) != 0) {
1301 struct syslog_data sd = SYSLOG_DATA_INIT;
1302 syslog_r(LOG_NOTICE|LOG_AUTH, &sd,
1303 AskedForGot, canonname, bp);
1304 cp += n;
1305 continue; /* XXX - had_error++ ? */
1306 }
1307 if (type == T_A && n != INADDRSZ) {
1308 cp += n;
1309 continue;
1310 }
1311 if (type == T_AAAA && n != IN6ADDRSZ) {
1312 cp += n;
1313 continue;
1314 }
1315 if (type == T_AAAA) {
1316 struct in6_addr in6;
1317 memcpy(&in6, cp, IN6ADDRSZ);
1318 if (IN6_IS_ADDR_V4MAPPED(&in6)) {
1319 cp += n;
1320 continue;
1321 }
1322 }
1323 if (!haveanswer) {
1324 int nn;
1325
1326 canonname = bp;
1327 nn = (int)strlen(bp) + 1; /* for the \0 */
1328 bp += nn;
1329 }
1330
1331 /* don't overwrite pai */
1332 ai = *pai;
1333 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
1334 afd = find_afd(ai.ai_family);
1335 if (afd == NULL) {
1336 cp += n;
1337 continue;
1338 }
1339 cur->ai_next = get_ai(&ai, afd, (const char *)cp);
1340 if (cur->ai_next == NULL)
1341 had_error++;
1342 while (cur && cur->ai_next)
1343 cur = cur->ai_next;
1344 cp += n;
1345 break;
1346 case T_SRV:
1347 /* Add to SRV list. Insertion sort on priority. */
1348 pri = _getshort(cp);
1349 cp += INT16SZ;
1350 weight = _getshort(cp);
1351 cp += INT16SZ;
1352 port = _getshort(cp);
1353 cp += INT16SZ;
1354 n = dn_expand(answer->buf, eom, cp, tbuf,
1355 (int)sizeof(tbuf));
1356 if ((n < 0) || !res_hnok(tbuf)) {
1357 had_error++;
1358 continue;
1359 }
1360 cp += n;
1361 if (strlen(tbuf) + 1 >= MAXDNAME) {
1362 had_error++;
1363 continue;
1364 }
1365 srv = malloc(sizeof(*srv));
1366 if (!srv) {
1367 had_error++;
1368 continue;
1369 }
1370 strlcpy(srv->name, tbuf, sizeof(srv->name));
1371 srv->pri = pri;
1372 srv->weight = weight;
1373 srv->port = port;
1374 /* Weight 0 is sorted before other weights. */
1375 if (!srvlist
1376 || srv->pri < srvlist->pri
1377 || (srv->pri == srvlist->pri &&
1378 (!srv->weight || srvlist->weight))) {
1379 srv->next = srvlist;
1380 srvlist = srv;
1381 } else {
1382 for (csrv = srvlist;
1383 csrv->next && csrv->next->pri <= srv->pri;
1384 csrv = csrv->next) {
1385 if (csrv->next->pri == srv->pri
1386 && (!srv->weight ||
1387 csrv->next->weight))
1388 break;
1389 }
1390 srv->next = csrv->next;
1391 csrv->next = srv;
1392 }
1393 continue; /* Don't add to haveanswer yet. */
1394 default:
1395 abort();
1396 }
1397 if (!had_error)
1398 haveanswer++;
1399 }
1400
1401 if (srvlist) {
1402 res_state res;
1403 /*
1404 * Check for explicit rejection.
1405 */
1406 if (!srvlist->next && !srvlist->name[0]) {
1407 free(srvlist);
1408 h_errno = HOST_NOT_FOUND;
1409 return NULL;
1410 }
1411 res = __res_get_state();
1412 if (res == NULL) {
1413 while (srvlist != NULL) {
1414 srv = srvlist;
1415 srvlist = srvlist->next;
1416 free(srv);
1417 }
1418 h_errno = NETDB_INTERNAL;
1419 return NULL;
1420 }
1421
1422 while (srvlist) {
1423 struct res_target q, q2;
1424
1425 srv = srvlist;
1426 srvlist = srvlist->next;
1427
1428 /*
1429 * Since res_* doesn't give the additional
1430 * section, we always look up.
1431 */
1432 memset(&q, 0, sizeof(q));
1433 memset(&q2, 0, sizeof(q2));
1434
1435 q.name = srv->name;
1436 q.qclass = C_IN;
1437 q.qtype = T_AAAA;
1438 q.next = &q2;
1439 q2.name = srv->name;
1440 q2.qclass = C_IN;
1441 q2.qtype = T_A;
1442
1443 aip = _dns_query(&q, pai, res, 0);
1444
1445 if (aip != NULL) {
1446 cur->ai_next = aip;
1447 while (cur && cur->ai_next) {
1448 cur = cur->ai_next;
1449 *getport(cur) = htons(srv->port);
1450 haveanswer++;
1451 }
1452 }
1453 free(srv);
1454 }
1455 __res_put_state(res);
1456 }
1457 if (haveanswer) {
1458 if (!sentinel.ai_next->ai_canonname)
1459 (void)get_canonname(pai, sentinel.ai_next,
1460 canonname ? canonname : qname);
1461 h_errno = NETDB_SUCCESS;
1462 return sentinel.ai_next;
1463 }
1464
1465 h_errno = NO_RECOVERY;
1466 return NULL;
1467 }
1468
1469 #define SORTEDADDR(p) (((struct sockaddr_in *)(void *)(p->ai_next->ai_addr))->sin_addr.s_addr)
1470 #define SORTMATCH(p, s) ((SORTEDADDR(p) & (s).mask) == (s).addr.s_addr)
1471
1472 static void
aisort(struct addrinfo * s,res_state res)1473 aisort(struct addrinfo *s, res_state res)
1474 {
1475 struct addrinfo head, *t, *p;
1476 int i;
1477
1478 head.ai_next = NULL;
1479 t = &head;
1480
1481 for (i = 0; i < res->nsort; i++) {
1482 p = s;
1483 while (p->ai_next) {
1484 if ((p->ai_next->ai_family != AF_INET)
1485 || SORTMATCH(p, res->sort_list[i])) {
1486 t->ai_next = p->ai_next;
1487 t = t->ai_next;
1488 p->ai_next = p->ai_next->ai_next;
1489 } else {
1490 p = p->ai_next;
1491 }
1492 }
1493 }
1494
1495 /* add rest of list and reset s to the new list*/
1496 t->ai_next = s->ai_next;
1497 s->ai_next = head.ai_next;
1498 }
1499
1500 static struct addrinfo *
_dns_query(struct res_target * q,const struct addrinfo * pai,res_state res,int dosearch)1501 _dns_query(struct res_target *q, const struct addrinfo *pai,
1502 res_state res, int dosearch)
1503 {
1504 struct res_target *q2 = q->next;
1505 querybuf *buf, *buf2;
1506 struct addrinfo sentinel, *cur, *ai;
1507
1508 #ifdef DNS_DEBUG
1509 struct res_target *iter;
1510 for (iter = q; iter; iter = iter->next)
1511 printf("Query type %d for %s\n", iter->qtype, iter->name);
1512 #endif
1513
1514 buf = malloc(sizeof(*buf));
1515 if (buf == NULL) {
1516 h_errno = NETDB_INTERNAL;
1517 return NULL;
1518 }
1519 buf2 = malloc(sizeof(*buf2));
1520 if (buf2 == NULL) {
1521 free(buf);
1522 h_errno = NETDB_INTERNAL;
1523 return NULL;
1524 }
1525
1526 memset(&sentinel, 0, sizeof(sentinel));
1527 cur = &sentinel;
1528
1529 q->answer = buf->buf;
1530 q->anslen = sizeof(buf->buf);
1531 if (q2) {
1532 q2->answer = buf2->buf;
1533 q2->anslen = sizeof(buf2->buf);
1534 }
1535
1536 if (dosearch) {
1537 if (res_searchN(q->name, q, res) < 0)
1538 goto out;
1539 } else {
1540 if (res_queryN(q->name, q, res) < 0)
1541 goto out;
1542 }
1543
1544 ai = getanswer(buf, q->n, q->name, q->qtype, pai);
1545 if (ai) {
1546 cur->ai_next = ai;
1547 while (cur && cur->ai_next)
1548 cur = cur->ai_next;
1549 }
1550 if (q2) {
1551 ai = getanswer(buf2, q2->n, q2->name, q2->qtype, pai);
1552 if (ai)
1553 cur->ai_next = ai;
1554 }
1555 free(buf);
1556 free(buf2);
1557 return sentinel.ai_next;
1558 out:
1559 free(buf);
1560 free(buf2);
1561 return NULL;
1562 }
1563
1564 /*ARGSUSED*/
1565 static struct addrinfo *
_dns_srv_lookup(const char * name,const char * servname,const struct addrinfo * pai)1566 _dns_srv_lookup(const char *name, const char *servname,
1567 const struct addrinfo *pai)
1568 {
1569 static const char * const srvprotos[] = { "tcp", "udp" };
1570 static const int srvnottype[] = { SOCK_DGRAM, SOCK_STREAM };
1571 static const int nsrvprotos = 2;
1572 struct addrinfo sentinel, *cur, *ai;
1573 struct servent *serv, sv;
1574 struct servent_data svd;
1575 struct res_target q;
1576 res_state res;
1577 char *tname;
1578 int i;
1579
1580 res = __res_get_state();
1581 if (res == NULL)
1582 return NULL;
1583
1584 memset(&svd, 0, sizeof(svd));
1585 memset(&sentinel, 0, sizeof(sentinel));
1586 cur = &sentinel;
1587
1588 /*
1589 * Iterate over supported SRV protocols.
1590 * (currently UDP and TCP only)
1591 */
1592 for (i = 0; i < nsrvprotos; i++) {
1593 /*
1594 * Check that the caller didn't specify a hint
1595 * which precludes this protocol.
1596 */
1597 if (pai->ai_socktype == srvnottype[i])
1598 continue;
1599 /*
1600 * If the caller specified a port,
1601 * then lookup the database for the
1602 * official service name.
1603 */
1604 serv = getservbyname_r(servname, srvprotos[i], &sv, &svd);
1605 if (serv == NULL)
1606 continue;
1607
1608 /*
1609 * Construct service DNS name.
1610 */
1611 if (asprintf(&tname, "_%s._%s.%s", serv->s_name, serv->s_proto,
1612 name) < 0)
1613 continue;
1614
1615 memset(&q, 0, sizeof(q));
1616 q.name = tname;
1617 q.qclass = C_IN;
1618 q.qtype = T_SRV;
1619
1620 /*
1621 * Do SRV query.
1622 */
1623 ai = _dns_query(&q, pai, res, 1);
1624 if (ai) {
1625 cur->ai_next = ai;
1626 while (cur && cur->ai_next)
1627 cur = cur->ai_next;
1628 }
1629 free(tname);
1630 }
1631
1632 if (res->nsort)
1633 aisort(&sentinel, res);
1634
1635 __res_put_state(res);
1636
1637 return sentinel.ai_next;
1638 }
1639
1640 /*ARGSUSED*/
1641 static struct addrinfo *
_dns_host_lookup(const char * name,const struct addrinfo * pai)1642 _dns_host_lookup(const char *name, const struct addrinfo *pai)
1643 {
1644 struct res_target q, q2;
1645 struct addrinfo sentinel, *ai;
1646 res_state res;
1647
1648 res = __res_get_state();
1649 if (res == NULL)
1650 return NULL;
1651
1652 memset(&q, 0, sizeof(q2));
1653 memset(&q2, 0, sizeof(q2));
1654
1655 switch (pai->ai_family) {
1656 case AF_UNSPEC:
1657 /* prefer IPv6 */
1658 q.name = name;
1659 q.qclass = C_IN;
1660 q.qtype = T_AAAA;
1661 q.next = &q2;
1662 q2.name = name;
1663 q2.qclass = C_IN;
1664 q2.qtype = T_A;
1665 break;
1666 case AF_INET:
1667 q.name = name;
1668 q.qclass = C_IN;
1669 q.qtype = T_A;
1670 break;
1671 case AF_INET6:
1672 q.name = name;
1673 q.qclass = C_IN;
1674 q.qtype = T_AAAA;
1675 break;
1676 default:
1677 __res_put_state(res);
1678 h_errno = NETDB_INTERNAL;
1679 return NULL;
1680 }
1681
1682 ai = _dns_query(&q, pai, res, 1);
1683
1684 memset(&sentinel, 0, sizeof(sentinel));
1685 sentinel.ai_next = ai;
1686
1687 if (ai != NULL && res->nsort)
1688 aisort(&sentinel, res);
1689
1690 __res_put_state(res);
1691
1692 return sentinel.ai_next;
1693 }
1694
1695 /*ARGSUSED*/
1696 static int
_dns_getaddrinfo(void * rv,void * cb_data,va_list ap)1697 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
1698 {
1699 struct addrinfo *ai = NULL;
1700 const char *name, *servname;
1701 const struct addrinfo *pai;
1702
1703 name = va_arg(ap, char *);
1704 pai = va_arg(ap, const struct addrinfo *);
1705 servname = va_arg(ap, char *);
1706
1707 /*
1708 * Try doing SRV lookup on service first.
1709 */
1710 if (servname
1711 #ifdef AI_SRV
1712 && (pai->ai_flags & AI_SRV)
1713 #endif
1714 && !(pai->ai_flags & AI_NUMERICSERV)
1715 && str2number(servname) == -1) {
1716
1717 #ifdef DNS_DEBUG
1718 printf("%s: try SRV lookup\n", __func__);
1719 #endif
1720 ai = _dns_srv_lookup(name, servname, pai);
1721 }
1722
1723 /*
1724 * Do lookup on name.
1725 */
1726 if (ai == NULL) {
1727
1728 #ifdef DNS_DEBUG
1729 printf("%s: try HOST lookup\n", __func__);
1730 #endif
1731 ai = _dns_host_lookup(name, pai);
1732
1733 if (ai == NULL) {
1734 switch (h_errno) {
1735 case HOST_NOT_FOUND:
1736 return NS_NOTFOUND;
1737 case TRY_AGAIN:
1738 return NS_TRYAGAIN;
1739 default:
1740 return NS_UNAVAIL;
1741 }
1742 }
1743 }
1744
1745 *((struct addrinfo **)rv) = ai;
1746 return NS_SUCCESS;
1747 }
1748
1749 static void
_sethtent(FILE ** hostf)1750 _sethtent(FILE **hostf)
1751 {
1752
1753 if (!*hostf)
1754 *hostf = fopen(_PATH_HOSTS, "re");
1755 else
1756 rewind(*hostf);
1757 }
1758
1759 static void
_endhtent(FILE ** hostf)1760 _endhtent(FILE **hostf)
1761 {
1762
1763 if (*hostf) {
1764 (void) fclose(*hostf);
1765 *hostf = NULL;
1766 }
1767 }
1768
1769 static struct addrinfo *
_gethtent(FILE ** hostf,const char * name,const struct addrinfo * pai)1770 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai)
1771 {
1772 char *p;
1773 char *cp, *tname, *cname;
1774 struct addrinfo hints, *res0, *res;
1775 int error;
1776 const char *addr;
1777 char hostbuf[8*1024];
1778
1779 _DIAGASSERT(name != NULL);
1780 _DIAGASSERT(pai != NULL);
1781
1782 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re")))
1783 return (NULL);
1784 again:
1785 if (!(p = fgets(hostbuf, (int)sizeof hostbuf, *hostf)))
1786 return (NULL);
1787 if (*p == '#')
1788 goto again;
1789 if (!(cp = strpbrk(p, "#\n")))
1790 goto again;
1791 *cp = '\0';
1792 if (!(cp = strpbrk(p, " \t")))
1793 goto again;
1794 *cp++ = '\0';
1795 addr = p;
1796 /* if this is not something we're looking for, skip it. */
1797 cname = NULL;
1798 while (cp && *cp) {
1799 if (*cp == ' ' || *cp == '\t') {
1800 cp++;
1801 continue;
1802 }
1803 if (!cname)
1804 cname = cp;
1805 tname = cp;
1806 if ((cp = strpbrk(cp, " \t")) != NULL)
1807 *cp++ = '\0';
1808 if (strcasecmp(name, tname) == 0)
1809 goto found;
1810 }
1811 goto again;
1812
1813 found:
1814 hints = *pai;
1815 hints.ai_flags = AI_NUMERICHOST;
1816 error = getaddrinfo(addr, NULL, &hints, &res0);
1817 if (error)
1818 goto again;
1819 for (res = res0; res; res = res->ai_next) {
1820 /* cover it up */
1821 res->ai_flags = pai->ai_flags;
1822
1823 if (pai->ai_flags & AI_CANONNAME) {
1824 if (get_canonname(pai, res, cname) != 0) {
1825 freeaddrinfo(res0);
1826 goto again;
1827 }
1828 }
1829 }
1830 return res0;
1831 }
1832
1833 /*ARGSUSED*/
1834 static int
_files_getaddrinfo(void * rv,void * cb_data,va_list ap)1835 _files_getaddrinfo(void *rv, void *cb_data, va_list ap)
1836 {
1837 const char *name;
1838 const struct addrinfo *pai;
1839 struct addrinfo sentinel, *cur;
1840 struct addrinfo *p;
1841 #ifndef _REENTRANT
1842 static
1843 #endif
1844 FILE *hostf = NULL;
1845
1846 name = va_arg(ap, char *);
1847 pai = va_arg(ap, const struct addrinfo *);
1848
1849 memset(&sentinel, 0, sizeof(sentinel));
1850 cur = &sentinel;
1851
1852 _sethtent(&hostf);
1853 while ((p = _gethtent(&hostf, name, pai)) != NULL) {
1854 cur->ai_next = p;
1855 while (cur && cur->ai_next)
1856 cur = cur->ai_next;
1857 }
1858 _endhtent(&hostf);
1859
1860 *((struct addrinfo **)rv) = sentinel.ai_next;
1861 if (sentinel.ai_next == NULL)
1862 return NS_NOTFOUND;
1863 return NS_SUCCESS;
1864 }
1865
1866 #ifdef YP
1867 /*ARGSUSED*/
1868 static struct addrinfo *
_yphostent(char * line,const struct addrinfo * pai)1869 _yphostent(char *line, const struct addrinfo *pai)
1870 {
1871 struct addrinfo sentinel, *cur;
1872 struct addrinfo hints, *res, *res0;
1873 int error;
1874 char *p;
1875 const char *addr, *canonname;
1876 char *nextline;
1877 char *cp;
1878
1879 _DIAGASSERT(line != NULL);
1880 _DIAGASSERT(pai != NULL);
1881
1882 p = line;
1883 addr = canonname = NULL;
1884
1885 memset(&sentinel, 0, sizeof(sentinel));
1886 cur = &sentinel;
1887
1888 nextline:
1889 /* terminate line */
1890 cp = strchr(p, '\n');
1891 if (cp) {
1892 *cp++ = '\0';
1893 nextline = cp;
1894 } else
1895 nextline = NULL;
1896
1897 cp = strpbrk(p, " \t");
1898 if (cp == NULL) {
1899 if (canonname == NULL)
1900 return (NULL);
1901 else
1902 goto done;
1903 }
1904 *cp++ = '\0';
1905
1906 addr = p;
1907
1908 while (cp && *cp) {
1909 if (*cp == ' ' || *cp == '\t') {
1910 cp++;
1911 continue;
1912 }
1913 if (!canonname)
1914 canonname = cp;
1915 if ((cp = strpbrk(cp, " \t")) != NULL)
1916 *cp++ = '\0';
1917 }
1918
1919 hints = *pai;
1920 hints.ai_flags = AI_NUMERICHOST;
1921 error = getaddrinfo(addr, NULL, &hints, &res0);
1922 if (error == 0) {
1923 for (res = res0; res; res = res->ai_next) {
1924 /* cover it up */
1925 res->ai_flags = pai->ai_flags;
1926
1927 if (pai->ai_flags & AI_CANONNAME)
1928 (void)get_canonname(pai, res, canonname);
1929 }
1930 } else
1931 res0 = NULL;
1932 if (res0) {
1933 cur->ai_next = res0;
1934 while (cur->ai_next)
1935 cur = cur->ai_next;
1936 }
1937
1938 if (nextline) {
1939 p = nextline;
1940 goto nextline;
1941 }
1942
1943 done:
1944 return sentinel.ai_next;
1945 }
1946
1947 /*ARGSUSED*/
1948 static int
_yp_getaddrinfo(void * rv,void * cb_data,va_list ap)1949 _yp_getaddrinfo(void *rv, void *cb_data, va_list ap)
1950 {
1951 struct addrinfo sentinel, *cur;
1952 struct addrinfo *ai = NULL;
1953 char *ypbuf;
1954 int ypbuflen, r;
1955 const char *name;
1956 const struct addrinfo *pai;
1957 char *ypdomain;
1958
1959 if (_yp_check(&ypdomain) == 0)
1960 return NS_UNAVAIL;
1961
1962 name = va_arg(ap, char *);
1963 pai = va_arg(ap, const struct addrinfo *);
1964
1965 memset(&sentinel, 0, sizeof(sentinel));
1966 cur = &sentinel;
1967
1968 /* hosts.byname is only for IPv4 (Solaris8) */
1969 if (pai->ai_family == PF_UNSPEC || pai->ai_family == PF_INET) {
1970 r = yp_match(ypdomain, "hosts.byname", name,
1971 (int)strlen(name), &ypbuf, &ypbuflen);
1972 if (r == 0) {
1973 struct addrinfo ai4;
1974
1975 ai4 = *pai;
1976 ai4.ai_family = AF_INET;
1977 ai = _yphostent(ypbuf, &ai4);
1978 if (ai) {
1979 cur->ai_next = ai;
1980 while (cur && cur->ai_next)
1981 cur = cur->ai_next;
1982 }
1983 }
1984 free(ypbuf);
1985 }
1986
1987 /* ipnodes.byname can hold both IPv4/v6 */
1988 r = yp_match(ypdomain, "ipnodes.byname", name,
1989 (int)strlen(name), &ypbuf, &ypbuflen);
1990 if (r == 0) {
1991 ai = _yphostent(ypbuf, pai);
1992 if (ai)
1993 cur->ai_next = ai;
1994 free(ypbuf);
1995 }
1996
1997 if (sentinel.ai_next == NULL) {
1998 h_errno = HOST_NOT_FOUND;
1999 return NS_NOTFOUND;
2000 }
2001 *((struct addrinfo **)rv) = sentinel.ai_next;
2002 return NS_SUCCESS;
2003 }
2004 #endif
2005
2006 /* resolver logic */
2007
2008 /*
2009 * Formulate a normal query, send, and await answer.
2010 * Returned answer is placed in supplied buffer "answer".
2011 * Perform preliminary check of answer, returning success only
2012 * if no error is indicated and the answer count is nonzero.
2013 * Return the size of the response on success, -1 on error.
2014 * Error number is left in h_errno.
2015 *
2016 * Caller must parse answer and determine whether it answers the question.
2017 */
2018 static int
res_queryN(const char * name,struct res_target * target,res_state res)2019 res_queryN(const char *name, /* domain name */ struct res_target *target,
2020 res_state res)
2021 {
2022 u_char buf[MAXPACKET];
2023 HEADER *hp;
2024 int n;
2025 struct res_target *t;
2026 int rcode;
2027 int ancount;
2028
2029 _DIAGASSERT(name != NULL);
2030 /* XXX: target may be NULL??? */
2031
2032 rcode = NOERROR;
2033 ancount = 0;
2034
2035 for (t = target; t; t = t->next) {
2036 int class, type;
2037 u_char *answer;
2038 int anslen;
2039
2040 hp = (HEADER *)(void *)t->answer;
2041 hp->rcode = NOERROR; /* default */
2042
2043 /* make it easier... */
2044 class = t->qclass;
2045 type = t->qtype;
2046 answer = t->answer;
2047 anslen = t->anslen;
2048 #ifdef DEBUG
2049 if (res->options & RES_DEBUG)
2050 printf(";; res_nquery(%s, %d, %d)\n", name, class, type);
2051 #endif
2052
2053 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
2054 buf, (int)sizeof(buf));
2055 #ifdef RES_USE_EDNS0
2056 if (n > 0 && (res->options & RES_USE_EDNS0) != 0)
2057 n = res_nopt(res, n, buf, (int)sizeof(buf), anslen);
2058 #endif
2059 if (n <= 0) {
2060 #ifdef DEBUG
2061 if (res->options & RES_DEBUG)
2062 printf(";; res_nquery: mkquery failed\n");
2063 #endif
2064 h_errno = NO_RECOVERY;
2065 return n;
2066 }
2067 n = res_nsend(res, buf, n, answer, anslen);
2068 #if 0
2069 if (n < 0) {
2070 #ifdef DEBUG
2071 if (res->options & RES_DEBUG)
2072 printf(";; res_query: send error\n");
2073 #endif
2074 h_errno = TRY_AGAIN;
2075 return n;
2076 }
2077 #endif
2078
2079 if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
2080 rcode = hp->rcode; /* record most recent error */
2081 #ifdef DEBUG
2082 if (res->options & RES_DEBUG)
2083 printf(";; rcode = %u, ancount=%u\n", hp->rcode,
2084 ntohs(hp->ancount));
2085 #endif
2086 continue;
2087 }
2088
2089 ancount += ntohs(hp->ancount);
2090
2091 t->n = n;
2092 }
2093
2094 if (ancount == 0) {
2095 switch (rcode) {
2096 case NXDOMAIN:
2097 h_errno = HOST_NOT_FOUND;
2098 break;
2099 case SERVFAIL:
2100 h_errno = TRY_AGAIN;
2101 break;
2102 case NOERROR:
2103 h_errno = NO_DATA;
2104 break;
2105 case FORMERR:
2106 case NOTIMP:
2107 case REFUSED:
2108 default:
2109 h_errno = NO_RECOVERY;
2110 break;
2111 }
2112 return -1;
2113 }
2114 return ancount;
2115 }
2116
2117 /*
2118 * Formulate a normal query, send, and retrieve answer in supplied buffer.
2119 * Return the size of the response on success, -1 on error.
2120 * If enabled, implement search rules until answer or unrecoverable failure
2121 * is detected. Error code, if any, is left in h_errno.
2122 */
2123 static int
res_searchN(const char * name,struct res_target * target,res_state res)2124 res_searchN(const char *name, struct res_target *target, res_state res)
2125 {
2126 const char *cp, * const *domain;
2127 HEADER *hp;
2128 u_int dots;
2129 char buf[MAXHOSTNAMELEN];
2130 int trailing_dot, ret, saved_herrno;
2131 int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
2132
2133 _DIAGASSERT(name != NULL);
2134 _DIAGASSERT(target != NULL);
2135
2136 hp = (HEADER *)(void *)target->answer; /*XXX*/
2137
2138 errno = 0;
2139 h_errno = HOST_NOT_FOUND; /* default, if we never query */
2140 dots = 0;
2141 for (cp = name; *cp; cp++)
2142 dots += (*cp == '.');
2143 trailing_dot = 0;
2144 if (cp > name && *--cp == '.')
2145 trailing_dot++;
2146
2147 /*
2148 * if there aren't any dots, it could be a user-level alias
2149 */
2150 if (!dots && (cp = res_hostalias(res, name, buf, sizeof(buf))) != NULL) {
2151 ret = res_queryN(cp, target, res);
2152 return ret;
2153 }
2154
2155 /*
2156 * If there are dots in the name already, let's just give it a try
2157 * 'as is'. The threshold can be set with the "ndots" option.
2158 */
2159 saved_herrno = -1;
2160 if (dots >= res->ndots) {
2161 ret = res_querydomainN(name, NULL, target, res);
2162 if (ret > 0)
2163 return (ret);
2164 saved_herrno = h_errno;
2165 tried_as_is++;
2166 }
2167
2168 /*
2169 * We do at least one level of search if
2170 * - there is no dot and RES_DEFNAME is set, or
2171 * - there is at least one dot, there is no trailing dot,
2172 * and RES_DNSRCH is set.
2173 */
2174 if ((!dots && (res->options & RES_DEFNAMES)) ||
2175 (dots && !trailing_dot && (res->options & RES_DNSRCH))) {
2176 int done = 0;
2177
2178 for (domain = (const char * const *)res->dnsrch;
2179 *domain && !done;
2180 domain++) {
2181
2182 ret = res_querydomainN(name, *domain, target, res);
2183 if (ret > 0)
2184 return ret;
2185
2186 /*
2187 * If no server present, give up.
2188 * If name isn't found in this domain,
2189 * keep trying higher domains in the search list
2190 * (if that's enabled).
2191 * On a NO_DATA error, keep trying, otherwise
2192 * a wildcard entry of another type could keep us
2193 * from finding this entry higher in the domain.
2194 * If we get some other error (negative answer or
2195 * server failure), then stop searching up,
2196 * but try the input name below in case it's
2197 * fully-qualified.
2198 */
2199 if (errno == ECONNREFUSED) {
2200 h_errno = TRY_AGAIN;
2201 return -1;
2202 }
2203
2204 switch (h_errno) {
2205 case NO_DATA:
2206 got_nodata++;
2207 /* FALLTHROUGH */
2208 case HOST_NOT_FOUND:
2209 /* keep trying */
2210 break;
2211 case TRY_AGAIN:
2212 if (hp->rcode == SERVFAIL) {
2213 /* try next search element, if any */
2214 got_servfail++;
2215 break;
2216 }
2217 /* FALLTHROUGH */
2218 default:
2219 /* anything else implies that we're done */
2220 done++;
2221 }
2222 /*
2223 * if we got here for some reason other than DNSRCH,
2224 * we only wanted one iteration of the loop, so stop.
2225 */
2226 if (!(res->options & RES_DNSRCH))
2227 done++;
2228 }
2229 }
2230
2231 /*
2232 * if we have not already tried the name "as is", do that now.
2233 * note that we do this regardless of how many dots were in the
2234 * name or whether it ends with a dot.
2235 */
2236 if (!tried_as_is) {
2237 ret = res_querydomainN(name, NULL, target, res);
2238 if (ret > 0)
2239 return ret;
2240 }
2241
2242 /*
2243 * if we got here, we didn't satisfy the search.
2244 * if we did an initial full query, return that query's h_errno
2245 * (note that we wouldn't be here if that query had succeeded).
2246 * else if we ever got a nodata, send that back as the reason.
2247 * else send back meaningless h_errno, that being the one from
2248 * the last DNSRCH we did.
2249 */
2250 if (saved_herrno != -1)
2251 h_errno = saved_herrno;
2252 else if (got_nodata)
2253 h_errno = NO_DATA;
2254 else if (got_servfail)
2255 h_errno = TRY_AGAIN;
2256 return -1;
2257 }
2258
2259 /*
2260 * Perform a call on res_query on the concatenation of name and domain,
2261 * removing a trailing dot from name if domain is NULL.
2262 */
2263 static int
res_querydomainN(const char * name,const char * domain,struct res_target * target,res_state res)2264 res_querydomainN(const char *name, const char *domain,
2265 struct res_target *target, res_state res)
2266 {
2267 char nbuf[MAXDNAME];
2268 const char *longname = nbuf;
2269 size_t n, d;
2270
2271 _DIAGASSERT(name != NULL);
2272 /* XXX: target may be NULL??? */
2273
2274 #ifdef DEBUG
2275 if (res->options & RES_DEBUG)
2276 printf(";; res_querydomain(%s, %s)\n",
2277 name, domain?domain:"<Nil>");
2278 #endif
2279 if (domain == NULL) {
2280 /*
2281 * Check for trailing '.';
2282 * copy without '.' if present.
2283 */
2284 n = strlen(name);
2285 if (n + 1 > sizeof(nbuf)) {
2286 h_errno = NO_RECOVERY;
2287 return -1;
2288 }
2289 if (n > 0 && name[--n] == '.') {
2290 strncpy(nbuf, name, n);
2291 nbuf[n] = '\0';
2292 } else
2293 longname = name;
2294 } else {
2295 n = strlen(name);
2296 d = strlen(domain);
2297 if (n + 1 + d + 1 > sizeof(nbuf)) {
2298 h_errno = NO_RECOVERY;
2299 return -1;
2300 }
2301 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
2302 }
2303 return res_queryN(longname, target, res);
2304 }
2305
2306 #ifdef TEST
2307 int
main(int argc,char * argv[])2308 main(int argc, char *argv[]) {
2309 struct addrinfo *ai, *sai;
2310 int i, e;
2311 char buf[1024];
2312
2313 for (i = 1; i < argc; i++) {
2314 if ((e = getaddrinfo(argv[i], NULL, NULL, &sai)) != 0)
2315 warnx("%s: %s", argv[i], gai_strerror(e));
2316 for (ai = sai; ai; ai = ai->ai_next) {
2317 sockaddr_snprintf(buf, sizeof(buf), "%a", ai->ai_addr);
2318 printf("flags=0x%x family=%d socktype=%d protocol=%d "
2319 "addrlen=%zu addr=%s canonname=%s next=%p\n",
2320 ai->ai_flags,
2321 ai->ai_family,
2322 ai->ai_socktype,
2323 ai->ai_protocol,
2324 (size_t)ai->ai_addrlen,
2325 buf,
2326 ai->ai_canonname,
2327 ai->ai_next);
2328 }
2329 if (sai)
2330 freeaddrinfo(sai);
2331 }
2332 return 0;
2333 }
2334 #endif
2335