xref: /openbsd-src/lib/libc/asr/getaddrinfo_async.c (revision 373da8abb60949de81b32d3c8eaecdaabf17bdaa)
1 /*	$OpenBSD: getaddrinfo_async.c,v 1.60 2023/11/20 12:15:16 florian Exp $	*/
2 /*
3  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/types.h>
19 #include <sys/socket.h>
20 #include <sys/uio.h>
21 #include <netinet/in.h>
22 #include <arpa/nameser.h>
23 #include <net/if.h>
24 #include <netdb.h>
25 
26 #include <asr.h>
27 #include <errno.h>
28 #include <ifaddrs.h>
29 #include <resolv.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <unistd.h>
33 #include <limits.h>
34 
35 #include "asr_private.h"
36 
37 struct match {
38 	int family;
39 	int socktype;
40 	int protocol;
41 };
42 
43 static int getaddrinfo_async_run(struct asr_query *, struct asr_result *);
44 static int get_port(const char *, const char *, int);
45 static int iter_family(struct asr_query *, int);
46 static int addrinfo_add(struct asr_query *, const struct sockaddr *, const char *);
47 static int addrinfo_from_file(struct asr_query *, int,  FILE *);
48 static int addrinfo_from_pkt(struct asr_query *, char *, size_t);
49 static int addrconfig_setup(struct asr_query *);
50 
51 static const struct match matches[] = {
52 	{ PF_INET,	SOCK_DGRAM,	IPPROTO_UDP	},
53 	{ PF_INET,	SOCK_STREAM,	IPPROTO_TCP	},
54 	{ PF_INET,	SOCK_RAW,	0		},
55 	{ PF_INET6,	SOCK_DGRAM,	IPPROTO_UDP	},
56 	{ PF_INET6,	SOCK_STREAM,	IPPROTO_TCP	},
57 	{ PF_INET6,	SOCK_RAW,	0		},
58 	{ -1,		0,		0,		},
59 };
60 
61 #define MATCH_FAMILY(a, b) ((a) == matches[(b)].family || (a) == PF_UNSPEC)
62 #define MATCH_PROTO(a, b) ((a) == matches[(b)].protocol || (a) == 0 || matches[(b)].protocol == 0)
63 /* Do not match SOCK_RAW unless explicitly specified */
64 #define MATCH_SOCKTYPE(a, b) ((a) == matches[(b)].socktype || ((a) == 0 && \
65 				matches[(b)].socktype != SOCK_RAW))
66 
67 enum {
68 	DOM_INIT,
69 	DOM_DOMAIN,
70 	DOM_DONE
71 };
72 
73 struct asr_query *
74 getaddrinfo_async(const char *hostname, const char *servname,
75 	const struct addrinfo *hints, void *asr)
76 {
77 	struct asr_ctx		*ac;
78 	struct asr_query	*as;
79 
80 	if (hints == NULL || (hints->ai_flags & AI_NUMERICHOST) == 0)
81 		ac = _asr_use_resolver(asr);
82 	else
83 		ac = _asr_no_resolver();
84 	if ((as = _asr_async_new(ac, ASR_GETADDRINFO)) == NULL)
85 		goto abort; /* errno set */
86 	as->as_run = getaddrinfo_async_run;
87 
88 	if (hostname) {
89 		if ((as->as.ai.hostname = strdup(hostname)) == NULL)
90 			goto abort; /* errno set */
91 	}
92 	if (servname && (as->as.ai.servname = strdup(servname)) == NULL)
93 		goto abort; /* errno set */
94 	if (hints)
95 		memmove(&as->as.ai.hints, hints, sizeof *hints);
96 	else {
97 		memset(&as->as.ai.hints, 0, sizeof as->as.ai.hints);
98 		as->as.ai.hints.ai_family = PF_UNSPEC;
99 		as->as.ai.hints.ai_flags = AI_ADDRCONFIG;
100 	}
101 
102 	_asr_ctx_unref(ac);
103 	return (as);
104     abort:
105 	if (as)
106 		_asr_async_free(as);
107 	_asr_ctx_unref(ac);
108 	return (NULL);
109 }
110 DEF_WEAK(getaddrinfo_async);
111 
112 static int
113 getaddrinfo_async_run(struct asr_query *as, struct asr_result *ar)
114 {
115 	char		 fqdn[MAXDNAME];
116 	const char	*str;
117 	struct addrinfo	*ai;
118 	int		 i, family, r, is_localhost;
119 	FILE		*f;
120 	union {
121 		struct sockaddr		sa;
122 		struct sockaddr_in	sain;
123 		struct sockaddr_in6	sain6;
124 	} sa;
125 
126     next:
127 	switch (as->as_state) {
128 
129 	case ASR_STATE_INIT:
130 
131 		/*
132 		 * First, make sure the parameters are valid.
133 		 */
134 
135 		as->as_count = 0;
136 
137 		if (as->as.ai.hostname == NULL &&
138 		    as->as.ai.servname == NULL) {
139 			ar->ar_gai_errno = EAI_NONAME;
140 			async_set_state(as, ASR_STATE_HALT);
141 			break;
142 		}
143 
144 		if (as->as.ai.hostname && as->as.ai.hostname[0] == '\0') {
145 			ar->ar_gai_errno = EAI_NODATA;
146 			async_set_state(as, ASR_STATE_HALT);
147 			break;
148 		}
149 
150 		ai = &as->as.ai.hints;
151 
152 		if (ai->ai_addrlen ||
153 		    ai->ai_canonname ||
154 		    ai->ai_addr ||
155 		    ai->ai_next) {
156 			ar->ar_gai_errno = EAI_BADHINTS;
157 			async_set_state(as, ASR_STATE_HALT);
158 			break;
159 		}
160 
161 		if (ai->ai_flags & ~AI_MASK ||
162 		    (ai->ai_flags & AI_CANONNAME && ai->ai_flags & AI_FQDN)) {
163 			ar->ar_gai_errno = EAI_BADFLAGS;
164 			async_set_state(as, ASR_STATE_HALT);
165 			break;
166 		}
167 
168 		if (ai->ai_family != PF_UNSPEC &&
169 		    ai->ai_family != PF_INET &&
170 		    ai->ai_family != PF_INET6) {
171 			ar->ar_gai_errno = EAI_FAMILY;
172 			async_set_state(as, ASR_STATE_HALT);
173 			break;
174 		}
175 
176 		if (ai->ai_socktype &&
177 		    ai->ai_socktype != SOCK_DGRAM  &&
178 		    ai->ai_socktype != SOCK_STREAM &&
179 		    ai->ai_socktype != SOCK_RAW) {
180 			ar->ar_gai_errno = EAI_SOCKTYPE;
181 			async_set_state(as, ASR_STATE_HALT);
182 			break;
183 		}
184 
185 		if (ai->ai_socktype == SOCK_RAW &&
186 		    get_port(as->as.ai.servname, NULL, 1) != 0) {
187 			ar->ar_gai_errno = EAI_SERVICE;
188 			async_set_state(as, ASR_STATE_HALT);
189 			break;
190 		}
191 
192 		/* Restrict result set to configured address families */
193 		if (ai->ai_flags & AI_ADDRCONFIG) {
194 			if (addrconfig_setup(as) == -1) {
195 				ar->ar_errno = errno;
196 				ar->ar_gai_errno = EAI_SYSTEM;
197 				async_set_state(as, ASR_STATE_HALT);
198 				break;
199 			}
200 		}
201 
202 		/* Make sure there is at least a valid combination */
203 		for (i = 0; matches[i].family != -1; i++)
204 			if (MATCH_FAMILY(ai->ai_family, i) &&
205 			    MATCH_SOCKTYPE(ai->ai_socktype, i) &&
206 			    MATCH_PROTO(ai->ai_protocol, i))
207 				break;
208 		if (matches[i].family == -1) {
209 			ar->ar_gai_errno = EAI_BADHINTS;
210 			async_set_state(as, ASR_STATE_HALT);
211 			break;
212 		}
213 
214 		if (ai->ai_protocol == 0 || ai->ai_protocol == IPPROTO_UDP)
215 			as->as.ai.port_udp = get_port(as->as.ai.servname, "udp",
216 			    as->as.ai.hints.ai_flags & AI_NUMERICSERV);
217 		if (ai->ai_protocol == 0 || ai->ai_protocol == IPPROTO_TCP)
218 			as->as.ai.port_tcp = get_port(as->as.ai.servname, "tcp",
219 			    as->as.ai.hints.ai_flags & AI_NUMERICSERV);
220 		if (as->as.ai.port_tcp == -2 || as->as.ai.port_udp == -2 ||
221 		    (as->as.ai.port_tcp == -1 && as->as.ai.port_udp == -1) ||
222 		    (ai->ai_protocol && (as->as.ai.port_udp == -1 ||
223 					 as->as.ai.port_tcp == -1))) {
224 			ar->ar_gai_errno = EAI_SERVICE;
225 			async_set_state(as, ASR_STATE_HALT);
226 			break;
227 		}
228 
229 		ar->ar_gai_errno = 0;
230 
231 		is_localhost = _asr_is_localhost(as->as.ai.hostname);
232 		/*
233 		 * If hostname is NULL, "localhost" or falls within the
234 		 * ".localhost." domain, use local address.
235 		 * RFC 6761, 6.3:
236 		 * 3. Name resolution APIs and libraries SHOULD recognize
237 		 * localhost names as special and SHOULD always return the IP
238 		 * loopback address for address queries and negative responses
239 		 * for all other query types.  Name resolution APIs SHOULD NOT
240 		 * send queries for localhost names to their configured caching
241 		 * DNS server(s).
242 		 */
243 		if (as->as.ai.hostname == NULL || is_localhost) {
244 			for (family = iter_family(as, 1);
245 			    family != -1;
246 			    family = iter_family(as, 0)) {
247 				/*
248 				 * We could use statically built sockaddrs for
249 				 * those, rather than parsing over and over.
250 				 */
251 				if (family == PF_INET)
252 					str = (ai->ai_flags & AI_PASSIVE &&
253 					    !is_localhost) ? "0.0.0.0" :
254 					    "127.0.0.1";
255 				else /* PF_INET6 */
256 					str = (ai->ai_flags & AI_PASSIVE &&
257 					    !is_localhost) ? "::" : "::1";
258 				 /* This can't fail */
259 				_asr_sockaddr_from_str(&sa.sa, family, str);
260 				if ((r = addrinfo_add(as, &sa.sa, NULL))) {
261 					ar->ar_gai_errno = r;
262 					break;
263 				}
264 			}
265 			if (ar->ar_gai_errno == 0 && as->as_count == 0) {
266 				ar->ar_gai_errno = EAI_NODATA;
267 			}
268 			async_set_state(as, ASR_STATE_HALT);
269 			break;
270 		}
271 
272 		/* Try numeric addresses first */
273 		for (family = iter_family(as, 1);
274 		    family != -1;
275 		    family = iter_family(as, 0)) {
276 
277 			if (_asr_sockaddr_from_str(&sa.sa, family,
278 			    as->as.ai.hostname) == -1)
279 				continue;
280 
281 			if ((r = addrinfo_add(as, &sa.sa, NULL)))
282 				ar->ar_gai_errno = r;
283 			break;
284 		}
285 		if (ar->ar_gai_errno || as->as_count) {
286 			async_set_state(as, ASR_STATE_HALT);
287 			break;
288 		}
289 
290 		if (ai->ai_flags & AI_NUMERICHOST) {
291 			ar->ar_gai_errno = EAI_NONAME;
292 			async_set_state(as, ASR_STATE_HALT);
293 			break;
294 		}
295 
296 		/* make sure there are no funny characters in hostname */
297 		if (!hnok_lenient(as->as.ai.hostname)) {
298 			ar->ar_gai_errno = EAI_FAIL;
299 			async_set_state(as, ASR_STATE_HALT);
300 			break;
301 		}
302 
303 		async_set_state(as, ASR_STATE_NEXT_DB);
304 		break;
305 
306 	case ASR_STATE_NEXT_DB:
307 		if (_asr_iter_db(as) == -1) {
308 			async_set_state(as, ASR_STATE_NOT_FOUND);
309 			break;
310 		}
311 		as->as_family_idx = 0;
312 		async_set_state(as, ASR_STATE_SAME_DB);
313 		break;
314 
315 	case ASR_STATE_NEXT_FAMILY:
316 		as->as_family_idx += 1;
317 		if (as->as.ai.hints.ai_family != AF_UNSPEC ||
318 		    AS_FAMILY(as) == -1) {
319 			/* The family was specified, or we have tried all
320 			 * families with this DB.
321 			 */
322 			if (as->as_count) {
323 				ar->ar_gai_errno = 0;
324 				async_set_state(as, ASR_STATE_HALT);
325 			} else
326 				async_set_state(as, ASR_STATE_NEXT_DOMAIN);
327 			break;
328 		}
329 		async_set_state(as, ASR_STATE_SAME_DB);
330 		break;
331 
332 	case ASR_STATE_NEXT_DOMAIN:
333 		/* domain search is only for dns */
334 		if (AS_DB(as) != ASR_DB_DNS) {
335 			async_set_state(as, ASR_STATE_NEXT_DB);
336 			break;
337 		}
338 		as->as_family_idx = 0;
339 
340 		free(as->as.ai.fqdn);
341 		as->as.ai.fqdn = NULL;
342 		r = _asr_iter_domain(as, as->as.ai.hostname, fqdn, sizeof(fqdn));
343 		if (r == -1) {
344 			async_set_state(as, ASR_STATE_NEXT_DB);
345 			break;
346 		}
347 		if (r == 0) {
348 			ar->ar_gai_errno = EAI_FAIL;
349 			async_set_state(as, ASR_STATE_HALT);
350 			break;
351 		}
352 		as->as.ai.fqdn = strdup(fqdn);
353 		if (as->as.ai.fqdn == NULL) {
354 			ar->ar_gai_errno = EAI_MEMORY;
355 			async_set_state(as, ASR_STATE_HALT);
356 			break;
357 		}
358 
359 		async_set_state(as, ASR_STATE_SAME_DB);
360 		break;
361 
362 	case ASR_STATE_SAME_DB:
363 		/* query the current DB again */
364 		switch (AS_DB(as)) {
365 		case ASR_DB_DNS:
366 			if (as->as.ai.fqdn == NULL) {
367 				/* First try, initialize domain iteration */
368 				as->as_dom_flags = 0;
369 				as->as_dom_step = DOM_INIT;
370 				async_set_state(as, ASR_STATE_NEXT_DOMAIN);
371 				break;
372 			}
373 
374 			family = (as->as.ai.hints.ai_family == AF_UNSPEC) ?
375 			    AS_FAMILY(as) : as->as.ai.hints.ai_family;
376 
377 			if (family == AF_INET &&
378 			    as->as_flags & ASYNC_NO_INET) {
379 				async_set_state(as, ASR_STATE_NEXT_FAMILY);
380 				break;
381 			} else if (family == AF_INET6 &&
382 			    as->as_flags & ASYNC_NO_INET6) {
383 				async_set_state(as, ASR_STATE_NEXT_FAMILY);
384 				break;
385 			}
386 
387 			as->as_subq = _res_query_async_ctx(as->as.ai.fqdn,
388 			    C_IN, (family == AF_INET6) ? T_AAAA : T_A,
389 			    as->as_ctx);
390 
391 			if (as->as_subq == NULL) {
392 				if (errno == ENOMEM)
393 					ar->ar_gai_errno = EAI_MEMORY;
394 				else
395 					ar->ar_gai_errno = EAI_FAIL;
396 				async_set_state(as, ASR_STATE_HALT);
397 				break;
398 			}
399 			async_set_state(as, ASR_STATE_SUBQUERY);
400 			break;
401 
402 		case ASR_DB_FILE:
403 			f = fopen(_PATH_HOSTS, "re");
404 			if (f == NULL) {
405 				async_set_state(as, ASR_STATE_NEXT_DB);
406 				break;
407 			}
408 			family = (as->as.ai.hints.ai_family == AF_UNSPEC) ?
409 			    AS_FAMILY(as) : as->as.ai.hints.ai_family;
410 
411 			r = addrinfo_from_file(as, family, f);
412 			if (r == -1) {
413 				if (errno == ENOMEM)
414 					ar->ar_gai_errno = EAI_MEMORY;
415 				else
416 					ar->ar_gai_errno = EAI_FAIL;
417 				async_set_state(as, ASR_STATE_HALT);
418 			} else
419 				async_set_state(as, ASR_STATE_NEXT_FAMILY);
420 			fclose(f);
421 			break;
422 
423 		default:
424 			async_set_state(as, ASR_STATE_NEXT_DB);
425 		}
426 		break;
427 
428 	case ASR_STATE_SUBQUERY:
429 		if ((r = asr_run(as->as_subq, ar)) == ASYNC_COND)
430 			return (ASYNC_COND);
431 
432 		as->as_subq = NULL;
433 
434 		if (ar->ar_datalen == -1) {
435 			async_set_state(as, ASR_STATE_NEXT_FAMILY);
436 			break;
437 		}
438 
439 		r = addrinfo_from_pkt(as, ar->ar_data, ar->ar_datalen);
440 		if (r == -1) {
441 			if (errno == ENOMEM)
442 				ar->ar_gai_errno = EAI_MEMORY;
443 			else
444 				ar->ar_gai_errno = EAI_FAIL;
445 			async_set_state(as, ASR_STATE_HALT);
446 		} else
447 			async_set_state(as, ASR_STATE_NEXT_FAMILY);
448 		free(ar->ar_data);
449 		break;
450 
451 	case ASR_STATE_NOT_FOUND:
452 		/* No result found. Maybe we can try again. */
453 		if (as->as_flags & ASYNC_AGAIN)
454 			ar->ar_gai_errno = EAI_AGAIN;
455 		else
456 			ar->ar_gai_errno = EAI_NODATA;
457 		async_set_state(as, ASR_STATE_HALT);
458 		break;
459 
460 	case ASR_STATE_HALT:
461 		if (ar->ar_gai_errno == 0) {
462 			ar->ar_count = as->as_count;
463 			ar->ar_addrinfo = as->as.ai.aifirst;
464 			as->as.ai.aifirst = NULL;
465 		} else {
466 			ar->ar_count = 0;
467 			ar->ar_addrinfo = NULL;
468 		}
469 		return (ASYNC_DONE);
470 
471 	default:
472 		ar->ar_errno = EOPNOTSUPP;
473 		ar->ar_gai_errno = EAI_SYSTEM;
474 		async_set_state(as, ASR_STATE_HALT);
475 		break;
476 	}
477 	goto next;
478 }
479 
480 /*
481  * Retrieve the port number for the service name "servname" and
482  * the protocol "proto".
483  */
484 static int
485 get_port(const char *servname, const char *proto, int numonly)
486 {
487 	struct servent		se;
488 	struct servent_data	sed;
489 	int			port;
490 	const char		*e;
491 
492 	if (servname == NULL)
493 		return (0);
494 
495 	e = NULL;
496 	port = strtonum(servname, 0, USHRT_MAX, &e);
497 	if (e == NULL)
498 		return (port);
499 	if (errno == ERANGE)
500 		return (-2); /* invalid */
501 	if (numonly)
502 		return (-2);
503 
504 	port = -1;
505 	memset(&sed, 0, sizeof(sed));
506 	if (getservbyname_r(servname, proto, &se, &sed) != -1)
507 		port = ntohs(se.s_port);
508 	endservent_r(&sed);
509 
510 	return (port);
511 }
512 
513 /*
514  * Iterate over the address families that are to be queried. Use the
515  * list on the async context, unless a specific family was given in hints.
516  */
517 static int
518 iter_family(struct asr_query *as, int first)
519 {
520 	if (first) {
521 		as->as_family_idx = 0;
522 		if (as->as.ai.hints.ai_family != PF_UNSPEC)
523 			return as->as.ai.hints.ai_family;
524 		return AS_FAMILY(as);
525 	}
526 
527 	if (as->as.ai.hints.ai_family != PF_UNSPEC)
528 		return (-1);
529 
530 	as->as_family_idx++;
531 
532 	return AS_FAMILY(as);
533 }
534 
535 /*
536  * Use the sockaddr at "sa" to extend the result list on the "as" context,
537  * with the specified canonical name "cname". This function adds one
538  * entry per protocol/socktype match.
539  */
540 static int
541 addrinfo_add(struct asr_query *as, const struct sockaddr *sa, const char *cname)
542 {
543 	struct addrinfo		*ai;
544 	int			 i, port, proto;
545 
546 	for (i = 0; matches[i].family != -1; i++) {
547 		if (matches[i].family != sa->sa_family ||
548 		    !MATCH_SOCKTYPE(as->as.ai.hints.ai_socktype, i) ||
549 		    !MATCH_PROTO(as->as.ai.hints.ai_protocol, i))
550 			continue;
551 
552 		proto = as->as.ai.hints.ai_protocol;
553 		if (!proto)
554 			proto = matches[i].protocol;
555 
556 		if (proto == IPPROTO_TCP)
557 			port = as->as.ai.port_tcp;
558 		else if (proto == IPPROTO_UDP)
559 			port = as->as.ai.port_udp;
560 		else
561 			port = 0;
562 
563 		/* servname specified, but not defined for this protocol */
564 		if (port == -1)
565 			continue;
566 
567 		ai = calloc(1, sizeof(*ai) + sa->sa_len);
568 		if (ai == NULL)
569 			return (EAI_MEMORY);
570 		ai->ai_family = sa->sa_family;
571 		ai->ai_socktype = matches[i].socktype;
572 		ai->ai_protocol = proto;
573 		ai->ai_flags = as->as.ai.hints.ai_flags;
574 		ai->ai_addrlen = sa->sa_len;
575 		ai->ai_addr = (void *)(ai + 1);
576 		if (cname &&
577 		    as->as.ai.hints.ai_flags & (AI_CANONNAME | AI_FQDN)) {
578 			if ((ai->ai_canonname = strdup(cname)) == NULL) {
579 				free(ai);
580 				return (EAI_MEMORY);
581 			}
582 		}
583 		memmove(ai->ai_addr, sa, sa->sa_len);
584 		if (sa->sa_family == PF_INET)
585 			((struct sockaddr_in *)ai->ai_addr)->sin_port =
586 			    htons(port);
587 		else if (sa->sa_family == PF_INET6)
588 			((struct sockaddr_in6 *)ai->ai_addr)->sin6_port =
589 			    htons(port);
590 
591 		if (as->as.ai.aifirst == NULL)
592 			as->as.ai.aifirst = ai;
593 		if (as->as.ai.ailast)
594 			as->as.ai.ailast->ai_next = ai;
595 		as->as.ai.ailast = ai;
596 		as->as_count += 1;
597 	}
598 
599 	return (0);
600 }
601 
602 static int
603 addrinfo_from_file(struct asr_query *as, int family, FILE *f)
604 {
605 	char		*tokens[MAXTOKEN], *c, buf[BUFSIZ + 1];
606 	int		 n, i;
607 	union {
608 		struct sockaddr		sa;
609 		struct sockaddr_in	sain;
610 		struct sockaddr_in6	sain6;
611 	} u;
612 
613 	for (;;) {
614 		n = _asr_parse_namedb_line(f, tokens, MAXTOKEN, buf, sizeof(buf));
615 		if (n == -1)
616 			break; /* ignore errors reading the file */
617 
618 		for (i = 1; i < n; i++) {
619 			if (strcasecmp(as->as.ai.hostname, tokens[i]))
620 				continue;
621 			if (_asr_sockaddr_from_str(&u.sa, family, tokens[0]) == -1)
622 				continue;
623 			break;
624 		}
625 		if (i == n)
626 			continue;
627 
628 		if (as->as.ai.hints.ai_flags & (AI_CANONNAME | AI_FQDN))
629 			c = tokens[1];
630 		else
631 			c = NULL;
632 
633 		if (addrinfo_add(as, &u.sa, c))
634 			return (-1); /* errno set */
635 	}
636 	return (0);
637 }
638 
639 static int
640 addrinfo_from_pkt(struct asr_query *as, char *pkt, size_t pktlen)
641 {
642 	struct asr_unpack	 p;
643 	struct asr_dns_header	 h;
644 	struct asr_dns_query	 q;
645 	struct asr_dns_rr	 rr;
646 	int			 i;
647 	union {
648 		struct sockaddr		sa;
649 		struct sockaddr_in	sain;
650 		struct sockaddr_in6	sain6;
651 	} u;
652 	char		 buf[MAXDNAME], *c;
653 
654 	_asr_unpack_init(&p, pkt, pktlen);
655 	_asr_unpack_header(&p, &h);
656 	for (; h.qdcount; h.qdcount--)
657 		_asr_unpack_query(&p, &q);
658 
659 	for (i = 0; i < h.ancount; i++) {
660 		_asr_unpack_rr(&p, &rr);
661 		if (rr.rr_type != q.q_type ||
662 		    rr.rr_class != q.q_class)
663 			continue;
664 
665 		memset(&u, 0, sizeof u);
666 		if (rr.rr_type == T_A) {
667 			u.sain.sin_len = sizeof u.sain;
668 			u.sain.sin_family = AF_INET;
669 			u.sain.sin_addr = rr.rr.in_a.addr;
670 			u.sain.sin_port = 0;
671 		} else if (rr.rr_type == T_AAAA) {
672 			u.sain6.sin6_len = sizeof u.sain6;
673 			u.sain6.sin6_family = AF_INET6;
674 			u.sain6.sin6_addr = rr.rr.in_aaaa.addr6;
675 			u.sain6.sin6_port = 0;
676 		} else
677 			continue;
678 
679 		if (as->as.ai.hints.ai_flags & AI_CANONNAME) {
680 			_asr_strdname(rr.rr_dname, buf, sizeof buf);
681 			buf[strlen(buf) - 1] = '\0';
682 			c = res_hnok(buf) ? buf : NULL;
683 		} else if (as->as.ai.hints.ai_flags & AI_FQDN)
684 			c = as->as.ai.fqdn;
685 		else
686 			c = NULL;
687 
688 		if (addrinfo_add(as, &u.sa, c))
689 			return (-1); /* errno set */
690 	}
691 	return (0);
692 }
693 
694 static int
695 addrconfig_setup(struct asr_query *as)
696 {
697 	struct ifaddrs		*ifa, *ifa0;
698 	struct if_data		*ifa_data;
699 	struct sockaddr_in	*sinp;
700 	struct sockaddr_in6	*sin6p;
701 	int			 rtable, ifa_rtable = -1;
702 
703 	if (getifaddrs(&ifa0) == -1)
704 		return (-1);
705 
706 	rtable = getrtable();
707 
708 	as->as_flags |= ASYNC_NO_INET | ASYNC_NO_INET6;
709 
710 	for (ifa = ifa0; ifa != NULL; ifa = ifa->ifa_next) {
711 		if (ifa->ifa_addr == NULL)
712 			continue;
713 
714 		switch (ifa->ifa_addr->sa_family) {
715 		case PF_LINK:
716 			/* AF_LINK comes before inet / inet6 on an interface */
717 			ifa_data = (struct if_data *)ifa->ifa_data;
718 			ifa_rtable = ifa_data->ifi_rdomain;
719 			break;
720 		case PF_INET:
721 			if (ifa_rtable != rtable)
722 				continue;
723 
724 			sinp = (struct sockaddr_in *)ifa->ifa_addr;
725 
726 			if (sinp->sin_addr.s_addr == htonl(INADDR_LOOPBACK))
727 				continue;
728 
729 			as->as_flags &= ~ASYNC_NO_INET;
730 			break;
731 		case PF_INET6:
732 			if (ifa_rtable != rtable)
733 				continue;
734 
735 			sin6p = (struct sockaddr_in6 *)ifa->ifa_addr;
736 
737 			if (IN6_IS_ADDR_LOOPBACK(&sin6p->sin6_addr))
738 				continue;
739 
740 			if (IN6_IS_ADDR_LINKLOCAL(&sin6p->sin6_addr))
741 				continue;
742 
743 			as->as_flags &= ~ASYNC_NO_INET6;
744 			break;
745 		}
746 	}
747 
748 	freeifaddrs(ifa0);
749 
750 	return (0);
751 }
752