1 /*	$NetBSD: res_send.c,v 1.9 2006/01/24 17:41:25 christos Exp $	*/
2 
3 /*
4  * Copyright 2008  Android Open Source Project (source port randomization)
5  * Copyright (c) 1985, 1989, 1993
6  *    The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  * 	This product includes software developed by the University of
19  * 	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 /*
38  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
39  *
40  * Permission to use, copy, modify, and distribute this software for any
41  * purpose with or without fee is hereby granted, provided that the above
42  * copyright notice and this permission notice appear in all copies, and that
43  * the name of Digital Equipment Corporation not be used in advertising or
44  * publicity pertaining to distribution of the document or software without
45  * specific, written prior permission.
46  *
47  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
48  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
49  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
50  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
51  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
52  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
53  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
54  * SOFTWARE.
55  */
56 
57 /*
58  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
59  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
60  *
61  * Permission to use, copy, modify, and distribute this software for any
62  * purpose with or without fee is hereby granted, provided that the above
63  * copyright notice and this permission notice appear in all copies.
64  *
65  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
66  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
67  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
68  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
69  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
70  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
71  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
72  */
73 
74 #include <sys/cdefs.h>
75 #if defined(LIBC_SCCS) && !defined(lint)
76 #ifdef notdef
77 static const char sccsid[] = "@(#)res_send.c	8.1 (Berkeley) 6/4/93";
78 static const char rcsid[] = "Id: res_send.c,v 1.5.2.2.4.5 2004/08/10 02:19:56 marka Exp";
79 #else
80 __RCSID("$NetBSD: res_send.c,v 1.9 2006/01/24 17:41:25 christos Exp $");
81 #endif
82 #endif /* LIBC_SCCS and not lint */
83 
84 /* set to 1 to use our small/simple/limited DNS cache */
85 #define  USE_RESOLV_CACHE  1
86 
87 /*
88  * Send query to name server and wait for reply.
89  */
90 
91 #include <sys/types.h>
92 #include <sys/param.h>
93 #include <sys/time.h>
94 #include <sys/socket.h>
95 #include <sys/uio.h>
96 
97 #include <netinet/in.h>
98 #include <arpa/nameser.h>
99 #include <arpa/inet.h>
100 
101 #include <errno.h>
102 #include <fcntl.h>
103 #include <netdb.h>
104 #ifdef ANDROID_CHANGES
105 #include "resolv_netid.h"
106 #include "resolv_private.h"
107 #else
108 #include <resolv.h>
109 #endif
110 #include <signal.h>
111 #include <stdio.h>
112 #include <stdlib.h>
113 #include <string.h>
114 #include <time.h>
115 #include <unistd.h>
116 
117 #include <isc/eventlib.h>
118 
119 #if USE_RESOLV_CACHE
120 #  include <resolv_cache.h>
121 #endif
122 
123 #include "private/libc_logging.h"
124 
125 #ifndef DE_CONST
126 #define DE_CONST(c,v)   v = ((c) ? \
127     strchr((const void *)(c), *(const char *)(const void *)(c)) : NULL)
128 #endif
129 
130 /* Options.  Leave them on. */
131 #ifndef DEBUG
132 #define DEBUG
133 #endif
134 #include "res_debug.h"
135 #include "res_private.h"
136 
137 #define EXT(res) ((res)->_u._ext)
138 #define DBG 0
139 
140 static const int highestFD = FD_SETSIZE - 1;
141 
142 /* Forward. */
143 
144 static int		get_salen __P((const struct sockaddr *));
145 static struct sockaddr * get_nsaddr __P((res_state, size_t));
146 static int		send_vc(res_state, const u_char *, int,
147 				u_char *, int, int *, int);
148 static int		send_dg(res_state, const u_char *, int,
149 				u_char *, int, int *, int,
150 				int *, int *);
151 static void		Aerror(const res_state, FILE *, const char *, int,
152 			       const struct sockaddr *, int);
153 static void		Perror(const res_state, FILE *, const char *, int);
154 static int		sock_eq(struct sockaddr *, struct sockaddr *);
155 #ifdef NEED_PSELECT
156 static int		pselect(int, void *, void *, void *,
157 				struct timespec *,
158 				const sigset_t *);
159 #endif
160 void res_pquery(const res_state, const u_char *, int, FILE *);
161 static int connect_with_timeout(int sock, const struct sockaddr *nsap,
162 			socklen_t salen, int sec);
163 static int retrying_select(const int sock, fd_set *readset, fd_set *writeset,
164 			const struct timespec *finish);
165 
166 /* BIONIC-BEGIN: implement source port randomization */
167 typedef union {
168     struct sockaddr      sa;
169     struct sockaddr_in   sin;
170     struct sockaddr_in6  sin6;
171 } _sockaddr_union;
172 
173 static int
random_bind(int s,int family)174 random_bind( int  s, int  family )
175 {
176     _sockaddr_union  u;
177     int              j;
178     socklen_t        slen;
179 
180     /* clear all, this also sets the IP4/6 address to 'any' */
181     memset( &u, 0, sizeof u );
182 
183     switch (family) {
184         case AF_INET:
185             u.sin.sin_family = family;
186             slen             = sizeof u.sin;
187             break;
188         case AF_INET6:
189             u.sin6.sin6_family = family;
190             slen               = sizeof u.sin6;
191             break;
192         default:
193             errno = EPROTO;
194             return -1;
195     }
196 
197     /* first try to bind to a random source port a few times */
198     for (j = 0; j < 10; j++) {
199         /* find a random port between 1025 .. 65534 */
200         int  port = 1025 + (res_randomid() % (65535-1025));
201         if (family == AF_INET)
202             u.sin.sin_port = htons(port);
203         else
204             u.sin6.sin6_port = htons(port);
205 
206         if ( !bind( s, &u.sa, slen ) )
207             return 0;
208     }
209 
210     /* nothing after 10 tries, our network table is probably busy */
211     /* let the system decide which port is best */
212     if (family == AF_INET)
213         u.sin.sin_port = 0;
214     else
215         u.sin6.sin6_port = 0;
216 
217     return bind( s, &u.sa, slen );
218 }
219 /* BIONIC-END */
220 
221 static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
222 
223 /* Public. */
224 
225 /* int
226  * res_isourserver(ina)
227  *	looks up "ina" in _res.ns_addr_list[]
228  * returns:
229  *	0  : not found
230  *	>0 : found
231  * author:
232  *	paul vixie, 29may94
233  */
234 __LIBC_HIDDEN__ int
res_ourserver_p(const res_state statp,const struct sockaddr * sa)235 res_ourserver_p(const res_state statp, const struct sockaddr *sa) {
236 	const struct sockaddr_in *inp, *srv;
237 	const struct sockaddr_in6 *in6p, *srv6;
238 	int ns;
239 
240 	switch (sa->sa_family) {
241 	case AF_INET:
242 		inp = (const struct sockaddr_in *)(const void *)sa;
243 		for (ns = 0;  ns < statp->nscount;  ns++) {
244 			srv = (struct sockaddr_in *)(void *)get_nsaddr(statp, (size_t)ns);
245 			if (srv->sin_family == inp->sin_family &&
246 			    srv->sin_port == inp->sin_port &&
247 			    (srv->sin_addr.s_addr == INADDR_ANY ||
248 			     srv->sin_addr.s_addr == inp->sin_addr.s_addr))
249 				return (1);
250 		}
251 		break;
252 	case AF_INET6:
253 		if (EXT(statp).ext == NULL)
254 			break;
255 		in6p = (const struct sockaddr_in6 *)(const void *)sa;
256 		for (ns = 0;  ns < statp->nscount;  ns++) {
257 			srv6 = (struct sockaddr_in6 *)(void *)get_nsaddr(statp, (size_t)ns);
258 			if (srv6->sin6_family == in6p->sin6_family &&
259 			    srv6->sin6_port == in6p->sin6_port &&
260 #ifdef HAVE_SIN6_SCOPE_ID
261 			    (srv6->sin6_scope_id == 0 ||
262 			     srv6->sin6_scope_id == in6p->sin6_scope_id) &&
263 #endif
264 			    (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
265 			     IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr)))
266 				return (1);
267 		}
268 		break;
269 	default:
270 		break;
271 	}
272 	return (0);
273 }
274 
275 /* int
276  * res_nameinquery(name, type, class, buf, eom)
277  *	look for (name,type,class) in the query section of packet (buf,eom)
278  * requires:
279  *	buf + HFIXEDSZ <= eom
280  * returns:
281  *	-1 : format error
282  *	0  : not found
283  *	>0 : found
284  * author:
285  *	paul vixie, 29may94
286  */
287 int
res_nameinquery(const char * name,int type,int class,const u_char * buf,const u_char * eom)288 res_nameinquery(const char *name, int type, int class,
289 		const u_char *buf, const u_char *eom)
290 {
291 	const u_char *cp = buf + HFIXEDSZ;
292 	int qdcount = ntohs(((const HEADER*)(const void *)buf)->qdcount);
293 
294 	while (qdcount-- > 0) {
295 		char tname[MAXDNAME+1];
296 		int n, ttype, tclass;
297 
298 		n = dn_expand(buf, eom, cp, tname, sizeof tname);
299 		if (n < 0)
300 			return (-1);
301 		cp += n;
302 		if (cp + 2 * INT16SZ > eom)
303 			return (-1);
304 		ttype = ns_get16(cp); cp += INT16SZ;
305 		tclass = ns_get16(cp); cp += INT16SZ;
306 		if (ttype == type && tclass == class &&
307 		    ns_samename(tname, name) == 1)
308 			return (1);
309 	}
310 	return (0);
311 }
312 
313 /* int
314  * res_queriesmatch(buf1, eom1, buf2, eom2)
315  *	is there a 1:1 mapping of (name,type,class)
316  *	in (buf1,eom1) and (buf2,eom2)?
317  * returns:
318  *	-1 : format error
319  *	0  : not a 1:1 mapping
320  *	>0 : is a 1:1 mapping
321  * author:
322  *	paul vixie, 29may94
323  */
324 int
res_queriesmatch(const u_char * buf1,const u_char * eom1,const u_char * buf2,const u_char * eom2)325 res_queriesmatch(const u_char *buf1, const u_char *eom1,
326 		 const u_char *buf2, const u_char *eom2)
327 {
328 	const u_char *cp = buf1 + HFIXEDSZ;
329 	int qdcount = ntohs(((const HEADER*)(const void *)buf1)->qdcount);
330 
331 	if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
332 		return (-1);
333 
334 	/*
335 	 * Only header section present in replies to
336 	 * dynamic update packets.
337 	 */
338 	if ((((const HEADER *)(const void *)buf1)->opcode == ns_o_update) &&
339 	    (((const HEADER *)(const void *)buf2)->opcode == ns_o_update))
340 		return (1);
341 
342 	if (qdcount != ntohs(((const HEADER*)(const void *)buf2)->qdcount))
343 		return (0);
344 	while (qdcount-- > 0) {
345 		char tname[MAXDNAME+1];
346 		int n, ttype, tclass;
347 
348 		n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
349 		if (n < 0)
350 			return (-1);
351 		cp += n;
352 		if (cp + 2 * INT16SZ > eom1)
353 			return (-1);
354 		ttype = ns_get16(cp);	cp += INT16SZ;
355 		tclass = ns_get16(cp); cp += INT16SZ;
356 		if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
357 			return (0);
358 	}
359 	return (1);
360 }
361 
362 
363 int
res_nsend(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz)364 res_nsend(res_state statp,
365 	  const u_char *buf, int buflen, u_char *ans, int anssiz)
366 {
367 	int gotsomewhere, terrno, try, v_circuit, resplen, ns, n;
368 	char abuf[NI_MAXHOST];
369 #if USE_RESOLV_CACHE
370         ResolvCacheStatus     cache_status = RESOLV_CACHE_UNSUPPORTED;
371 #endif
372 
373 #if !USE_RESOLV_CACHE
374 	if (statp->nscount == 0) {
375 		errno = ESRCH;
376 		return (-1);
377 	}
378 #endif
379 
380 	if (anssiz < HFIXEDSZ) {
381 		errno = EINVAL;
382 		return (-1);
383 	}
384 	DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY),
385 		(stdout, ";; res_send()\n"), buf, buflen);
386 	v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
387 	gotsomewhere = 0;
388 	terrno = ETIMEDOUT;
389 
390 #if USE_RESOLV_CACHE
391 	int  anslen = 0;
392 	cache_status = _resolv_cache_lookup(
393 			statp->netid, buf, buflen,
394 			ans, anssiz, &anslen);
395 
396 	if (cache_status == RESOLV_CACHE_FOUND) {
397 		return anslen;
398 	} else if (cache_status != RESOLV_CACHE_UNSUPPORTED) {
399 		// had a cache miss for a known network, so populate the thread private
400 		// data so the normal resolve path can do its thing
401 		_resolv_populate_res_for_net(statp);
402 	}
403 
404 	if (statp->nscount == 0) {
405 		// We have no nameservers configured, so there's no point trying.
406 		// Tell the cache the query failed, or any retries and anyone else asking the same
407 		// question will block for PENDING_REQUEST_TIMEOUT seconds instead of failing fast.
408 		_resolv_cache_query_failed(statp->netid, buf, buflen);
409 		errno = ESRCH;
410 		return (-1);
411 	}
412 #endif
413 
414 	/*
415 	 * If the ns_addr_list in the resolver context has changed, then
416 	 * invalidate our cached copy and the associated timing data.
417 	 */
418 	if (EXT(statp).nscount != 0) {
419 		int needclose = 0;
420 		struct sockaddr_storage peer;
421 		socklen_t peerlen;
422 
423 		if (EXT(statp).nscount != statp->nscount)
424 			needclose++;
425 		else
426 			for (ns = 0; ns < statp->nscount; ns++) {
427 				if (statp->nsaddr_list[ns].sin_family &&
428 				    !sock_eq((struct sockaddr *)(void *)&statp->nsaddr_list[ns],
429 					     (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[ns])) {
430 					needclose++;
431 					break;
432 				}
433 
434 				if (EXT(statp).nssocks[ns] == -1)
435 					continue;
436 				peerlen = sizeof(peer);
437 				if (getpeername(EXT(statp).nssocks[ns],
438 				    (struct sockaddr *)(void *)&peer, &peerlen) < 0) {
439 					needclose++;
440 					break;
441 				}
442 				if (!sock_eq((struct sockaddr *)(void *)&peer,
443 				    get_nsaddr(statp, (size_t)ns))) {
444 					needclose++;
445 					break;
446 				}
447 			}
448 		if (needclose) {
449 			res_nclose(statp);
450 			EXT(statp).nscount = 0;
451 		}
452 	}
453 
454 	/*
455 	 * Maybe initialize our private copy of the ns_addr_list.
456 	 */
457 	if (EXT(statp).nscount == 0) {
458 		for (ns = 0; ns < statp->nscount; ns++) {
459 			EXT(statp).nstimes[ns] = RES_MAXTIME;
460 			EXT(statp).nssocks[ns] = -1;
461 			if (!statp->nsaddr_list[ns].sin_family)
462 				continue;
463 			EXT(statp).ext->nsaddrs[ns].sin =
464 				 statp->nsaddr_list[ns];
465 		}
466 		EXT(statp).nscount = statp->nscount;
467 	}
468 
469 	/*
470 	 * Some resolvers want to even out the load on their nameservers.
471 	 * Note that RES_BLAST overrides RES_ROTATE.
472 	 */
473 	if ((statp->options & RES_ROTATE) != 0U &&
474 	    (statp->options & RES_BLAST) == 0U) {
475 		union res_sockaddr_union inu;
476 		struct sockaddr_in ina;
477 		int lastns = statp->nscount - 1;
478 		int fd;
479 		u_int16_t nstime;
480 
481 		if (EXT(statp).ext != NULL)
482 			inu = EXT(statp).ext->nsaddrs[0];
483 		ina = statp->nsaddr_list[0];
484 		fd = EXT(statp).nssocks[0];
485 		nstime = EXT(statp).nstimes[0];
486 		for (ns = 0; ns < lastns; ns++) {
487 			if (EXT(statp).ext != NULL)
488                                 EXT(statp).ext->nsaddrs[ns] =
489 					EXT(statp).ext->nsaddrs[ns + 1];
490 			statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
491 			EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1];
492 			EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1];
493 		}
494 		if (EXT(statp).ext != NULL)
495 			EXT(statp).ext->nsaddrs[lastns] = inu;
496 		statp->nsaddr_list[lastns] = ina;
497 		EXT(statp).nssocks[lastns] = fd;
498 		EXT(statp).nstimes[lastns] = nstime;
499 	}
500 
501 	/*
502 	 * Send request, RETRY times, or until successful.
503 	 */
504 	for (try = 0; try < statp->retry; try++) {
505 	    for (ns = 0; ns < statp->nscount; ns++) {
506 		struct sockaddr *nsap;
507 		int nsaplen;
508 		nsap = get_nsaddr(statp, (size_t)ns);
509 		nsaplen = get_salen(nsap);
510 		statp->_flags &= ~RES_F_LASTMASK;
511 		statp->_flags |= (ns << RES_F_LASTSHIFT);
512  same_ns:
513 		if (statp->qhook) {
514 			int done = 0, loops = 0;
515 
516 			do {
517 				res_sendhookact act;
518 
519 				act = (*statp->qhook)(&nsap, &buf, &buflen,
520 						      ans, anssiz, &resplen);
521 				switch (act) {
522 				case res_goahead:
523 					done = 1;
524 					break;
525 				case res_nextns:
526 					res_nclose(statp);
527 					goto next_ns;
528 				case res_done:
529 					return (resplen);
530 				case res_modified:
531 					/* give the hook another try */
532 					if (++loops < 42) /*doug adams*/
533 						break;
534 					/*FALLTHROUGH*/
535 				case res_error:
536 					/*FALLTHROUGH*/
537 				default:
538 					goto fail;
539 				}
540 			} while (!done);
541 		}
542 
543 		Dprint(((statp->options & RES_DEBUG) &&
544 			getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf),
545 				NULL, 0, niflags) == 0),
546 				(stdout, ";; Querying server (# %d) address = %s\n",
547 				ns + 1, abuf));
548 
549 
550 		if (v_circuit) {
551 			/* Use VC; at most one attempt per server. */
552 			try = statp->retry;
553 
554 			n = send_vc(statp, buf, buflen, ans, anssiz, &terrno,
555 				    ns);
556 
557 			if (DBG) {
558 				__libc_format_log(ANDROID_LOG_DEBUG, "libc",
559 					"used send_vc %d\n", n);
560 			}
561 
562 			if (n < 0)
563 				goto fail;
564 			if (n == 0)
565 				goto next_ns;
566 			resplen = n;
567 		} else {
568 			/* Use datagrams. */
569 			if (DBG) {
570 				__libc_format_log(ANDROID_LOG_DEBUG, "libc", "using send_dg\n");
571 			}
572 
573 			n = send_dg(statp, buf, buflen, ans, anssiz, &terrno,
574 				    ns, &v_circuit, &gotsomewhere);
575 			if (DBG) {
576 				__libc_format_log(ANDROID_LOG_DEBUG, "libc", "used send_dg %d\n",n);
577 			}
578 
579 			if (n < 0)
580 				goto fail;
581 			if (n == 0)
582 				goto next_ns;
583 			if (DBG) {
584 				__libc_format_log(ANDROID_LOG_DEBUG, "libc", "time=%ld\n",
585                                                   time(NULL));
586 			}
587 			if (v_circuit)
588 				goto same_ns;
589 			resplen = n;
590 		}
591 
592 		Dprint((statp->options & RES_DEBUG) ||
593 		       ((statp->pfcode & RES_PRF_REPLY) &&
594 			(statp->pfcode & RES_PRF_HEAD1)),
595 		       (stdout, ";; got answer:\n"));
596 
597 		DprintQ((statp->options & RES_DEBUG) ||
598 			(statp->pfcode & RES_PRF_REPLY),
599 			(stdout, "%s", ""),
600 			ans, (resplen > anssiz) ? anssiz : resplen);
601 
602 #if USE_RESOLV_CACHE
603                 if (cache_status == RESOLV_CACHE_NOTFOUND) {
604                     _resolv_cache_add(statp->netid, buf, buflen,
605                                       ans, resplen);
606                 }
607 #endif
608 		/*
609 		 * If we have temporarily opened a virtual circuit,
610 		 * or if we haven't been asked to keep a socket open,
611 		 * close the socket.
612 		 */
613 		if ((v_circuit && (statp->options & RES_USEVC) == 0U) ||
614 		    (statp->options & RES_STAYOPEN) == 0U) {
615 			res_nclose(statp);
616 		}
617 		if (statp->rhook) {
618 			int done = 0, loops = 0;
619 
620 			do {
621 				res_sendhookact act;
622 
623 				act = (*statp->rhook)(nsap, buf, buflen,
624 						      ans, anssiz, &resplen);
625 				switch (act) {
626 				case res_goahead:
627 				case res_done:
628 					done = 1;
629 					break;
630 				case res_nextns:
631 					res_nclose(statp);
632 					goto next_ns;
633 				case res_modified:
634 					/* give the hook another try */
635 					if (++loops < 42) /*doug adams*/
636 						break;
637 					/*FALLTHROUGH*/
638 				case res_error:
639 					/*FALLTHROUGH*/
640 				default:
641 					goto fail;
642 				}
643 			} while (!done);
644 
645 		}
646 		return (resplen);
647  next_ns: ;
648 	   } /*foreach ns*/
649 	} /*foreach retry*/
650 	res_nclose(statp);
651 	if (!v_circuit) {
652 		if (!gotsomewhere)
653 			errno = ECONNREFUSED;	/* no nameservers found */
654 		else
655 			errno = ETIMEDOUT;	/* no answer obtained */
656 	} else
657 		errno = terrno;
658 
659 #if USE_RESOLV_CACHE
660         _resolv_cache_query_failed(statp->netid, buf, buflen);
661 #endif
662 
663 	return (-1);
664  fail:
665 #if USE_RESOLV_CACHE
666 	_resolv_cache_query_failed(statp->netid, buf, buflen);
667 #endif
668 	res_nclose(statp);
669 	return (-1);
670 }
671 
672 /* Private */
673 
674 static int
get_salen(sa)675 get_salen(sa)
676 	const struct sockaddr *sa;
677 {
678 
679 #ifdef HAVE_SA_LEN
680 	/* There are people do not set sa_len.  Be forgiving to them. */
681 	if (sa->sa_len)
682 		return (sa->sa_len);
683 #endif
684 
685 	if (sa->sa_family == AF_INET)
686 		return (sizeof(struct sockaddr_in));
687 	else if (sa->sa_family == AF_INET6)
688 		return (sizeof(struct sockaddr_in6));
689 	else
690 		return (0);	/* unknown, die on connect */
691 }
692 
693 /*
694  * pick appropriate nsaddr_list for use.  see res_init() for initialization.
695  */
696 static struct sockaddr *
get_nsaddr(statp,n)697 get_nsaddr(statp, n)
698 	res_state statp;
699 	size_t n;
700 {
701 
702 	if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) {
703 		/*
704 		 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger
705 		 *   than struct sockaddr, and
706 		 * - user code did not update statp->nsaddr_list[n].
707 		 */
708 		return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n];
709 	} else {
710 		/*
711 		 * - user code updated statp->nsaddr_list[n], or
712 		 * - statp->nsaddr_list[n] has the same content as
713 		 *   EXT(statp).ext->nsaddrs[n].
714 		 */
715 		return (struct sockaddr *)(void *)&statp->nsaddr_list[n];
716 	}
717 }
718 
get_timeout(const res_state statp,const int ns)719 static int get_timeout(const res_state statp, const int ns)
720 {
721 	int timeout = (statp->retrans << ns);
722 	if (ns > 0) {
723 		timeout /= statp->nscount;
724 	}
725 	if (timeout <= 0) {
726 		timeout = 1;
727 	}
728 	if (DBG) {
729 		__libc_format_log(ANDROID_LOG_DEBUG, "libc", "using timeout of %d sec\n", timeout);
730 	}
731 
732 	return timeout;
733 }
734 
735 static int
send_vc(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz,int * terrno,int ns)736 send_vc(res_state statp,
737 	const u_char *buf, int buflen, u_char *ans, int anssiz,
738 	int *terrno, int ns)
739 {
740 	const HEADER *hp = (const HEADER *)(const void *)buf;
741 	HEADER *anhp = (HEADER *)(void *)ans;
742 	struct sockaddr *nsap;
743 	int nsaplen;
744 	int truncating, connreset, resplen, n;
745 	struct iovec iov[2];
746 	u_short len;
747 	u_char *cp;
748 	void *tmp;
749 
750 	if (DBG) {
751 		__libc_format_log(ANDROID_LOG_DEBUG, "libc", "using send_vc\n");
752 	}
753 
754 	nsap = get_nsaddr(statp, (size_t)ns);
755 	nsaplen = get_salen(nsap);
756 
757 	connreset = 0;
758  same_ns:
759 	truncating = 0;
760 
761 	/* Are we still talking to whom we want to talk to? */
762 	if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {
763 		struct sockaddr_storage peer;
764 		socklen_t size = sizeof peer;
765 		unsigned old_mark;
766 		socklen_t mark_size = sizeof(old_mark);
767 		if (getpeername(statp->_vcsock,
768 				(struct sockaddr *)(void *)&peer, &size) < 0 ||
769 		    !sock_eq((struct sockaddr *)(void *)&peer, nsap) ||
770 			getsockopt(statp->_vcsock, SOL_SOCKET, SO_MARK, &old_mark, &mark_size) < 0 ||
771 			old_mark != statp->_mark) {
772 			res_nclose(statp);
773 			statp->_flags &= ~RES_F_VC;
774 		}
775 	}
776 
777 	if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
778 		if (statp->_vcsock >= 0)
779 			res_nclose(statp);
780 
781 		statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM | SOCK_CLOEXEC, 0);
782 		if (statp->_vcsock > highestFD) {
783 			res_nclose(statp);
784 			errno = ENOTSOCK;
785 		}
786 		if (statp->_vcsock < 0) {
787 			switch (errno) {
788 			case EPROTONOSUPPORT:
789 #ifdef EPFNOSUPPORT
790 			case EPFNOSUPPORT:
791 #endif
792 			case EAFNOSUPPORT:
793 				Perror(statp, stderr, "socket(vc)", errno);
794 				return (0);
795 			default:
796 				*terrno = errno;
797 				Perror(statp, stderr, "socket(vc)", errno);
798 				return (-1);
799 			}
800 		}
801 		if (statp->_mark != MARK_UNSET) {
802 			if (setsockopt(statp->_vcsock, SOL_SOCKET,
803 				        SO_MARK, &statp->_mark, sizeof(statp->_mark)) < 0) {
804 				*terrno = errno;
805 				Perror(statp, stderr, "setsockopt", errno);
806 				return -1;
807 			}
808 		}
809 		errno = 0;
810 		if (random_bind(statp->_vcsock,nsap->sa_family) < 0) {
811 			*terrno = errno;
812 			Aerror(statp, stderr, "bind/vc", errno, nsap,
813 			    nsaplen);
814 			res_nclose(statp);
815 			return (0);
816 		}
817 		if (connect_with_timeout(statp->_vcsock, nsap, (socklen_t)nsaplen,
818 				get_timeout(statp, ns)) < 0) {
819 			*terrno = errno;
820 			Aerror(statp, stderr, "connect/vc", errno, nsap,
821 			    nsaplen);
822 			res_nclose(statp);
823 			return (0);
824 		}
825 		statp->_flags |= RES_F_VC;
826 	}
827 
828 	/*
829 	 * Send length & message
830 	 */
831 	ns_put16((u_short)buflen, (u_char*)(void *)&len);
832 	iov[0] = evConsIovec(&len, INT16SZ);
833 	DE_CONST(buf, tmp);
834 	iov[1] = evConsIovec(tmp, (size_t)buflen);
835 	if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {
836 		*terrno = errno;
837 		Perror(statp, stderr, "write failed", errno);
838 		res_nclose(statp);
839 		return (0);
840 	}
841 	/*
842 	 * Receive length & response
843 	 */
844  read_len:
845 	cp = ans;
846 	len = INT16SZ;
847 	while ((n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0) {
848 		cp += n;
849 		if ((len -= n) == 0)
850 			break;
851 	}
852 	if (n <= 0) {
853 		*terrno = errno;
854 		Perror(statp, stderr, "read failed", errno);
855 		res_nclose(statp);
856 		/*
857 		 * A long running process might get its TCP
858 		 * connection reset if the remote server was
859 		 * restarted.  Requery the server instead of
860 		 * trying a new one.  When there is only one
861 		 * server, this means that a query might work
862 		 * instead of failing.  We only allow one reset
863 		 * per query to prevent looping.
864 		 */
865 		if (*terrno == ECONNRESET && !connreset) {
866 			connreset = 1;
867 			res_nclose(statp);
868 			goto same_ns;
869 		}
870 		res_nclose(statp);
871 		return (0);
872 	}
873 	resplen = ns_get16(ans);
874 	if (resplen > anssiz) {
875 		Dprint(statp->options & RES_DEBUG,
876 		       (stdout, ";; response truncated\n")
877 		       );
878 		truncating = 1;
879 		len = anssiz;
880 	} else
881 		len = resplen;
882 	if (len < HFIXEDSZ) {
883 		/*
884 		 * Undersized message.
885 		 */
886 		Dprint(statp->options & RES_DEBUG,
887 		       (stdout, ";; undersized: %d\n", len));
888 		*terrno = EMSGSIZE;
889 		res_nclose(statp);
890 		return (0);
891 	}
892 	cp = ans;
893 	while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0){
894 		cp += n;
895 		len -= n;
896 	}
897 	if (n <= 0) {
898 		*terrno = errno;
899 		Perror(statp, stderr, "read(vc)", errno);
900 		res_nclose(statp);
901 		return (0);
902 	}
903 	if (truncating) {
904 		/*
905 		 * Flush rest of answer so connection stays in synch.
906 		 */
907 		anhp->tc = 1;
908 		len = resplen - anssiz;
909 		while (len != 0) {
910 			char junk[PACKETSZ];
911 
912 			n = read(statp->_vcsock, junk,
913 				 (len > sizeof junk) ? sizeof junk : len);
914 			if (n > 0)
915 				len -= n;
916 			else
917 				break;
918 		}
919 	}
920 	/*
921 	 * If the calling applicating has bailed out of
922 	 * a previous call and failed to arrange to have
923 	 * the circuit closed or the server has got
924 	 * itself confused, then drop the packet and
925 	 * wait for the correct one.
926 	 */
927 	if (hp->id != anhp->id) {
928 		DprintQ((statp->options & RES_DEBUG) ||
929 			(statp->pfcode & RES_PRF_REPLY),
930 			(stdout, ";; old answer (unexpected):\n"),
931 			ans, (resplen > anssiz) ? anssiz: resplen);
932 		goto read_len;
933 	}
934 
935 	/*
936 	 * All is well, or the error is fatal.  Signal that the
937 	 * next nameserver ought not be tried.
938 	 */
939 	return (resplen);
940 }
941 
942 /* return -1 on error (errno set), 0 on success */
943 static int
connect_with_timeout(int sock,const struct sockaddr * nsap,socklen_t salen,int sec)944 connect_with_timeout(int sock, const struct sockaddr *nsap, socklen_t salen, int sec)
945 {
946 	int res, origflags;
947 	fd_set rset, wset;
948 	struct timespec now, timeout, finish;
949 
950 	origflags = fcntl(sock, F_GETFL, 0);
951 	fcntl(sock, F_SETFL, origflags | O_NONBLOCK);
952 
953 	res = __connect(sock, nsap, salen);
954 	if (res < 0 && errno != EINPROGRESS) {
955                 res = -1;
956                 goto done;
957 	}
958 	if (res != 0) {
959 		now = evNowTime();
960 		timeout = evConsTime((long)sec, 0L);
961 		finish = evAddTime(now, timeout);
962 		if (DBG) {
963 			__libc_format_log(ANDROID_LOG_DEBUG, "libc", "  %d send_vc\n", sock);
964 		}
965 
966 		res = retrying_select(sock, &rset, &wset, &finish);
967 		if (res <= 0) {
968                         res = -1;
969 		}
970 	}
971 done:
972 	fcntl(sock, F_SETFL, origflags);
973 	if (DBG) {
974 		__libc_format_log(ANDROID_LOG_DEBUG, "libc",
975 			"  %d connect_with_timeout returning %d\n", sock, res);
976 	}
977 	return res;
978 }
979 
980 static int
retrying_select(const int sock,fd_set * readset,fd_set * writeset,const struct timespec * finish)981 retrying_select(const int sock, fd_set *readset, fd_set *writeset, const struct timespec *finish)
982 {
983 	struct timespec now, timeout;
984 	int n, error;
985 	socklen_t len;
986 
987 
988 retry:
989 	if (DBG) {
990 		__libc_format_log(ANDROID_LOG_DEBUG, "libc", "  %d retying_select\n", sock);
991 	}
992 
993 	now = evNowTime();
994 	if (readset) {
995 		FD_ZERO(readset);
996 		FD_SET(sock, readset);
997 	}
998 	if (writeset) {
999 		FD_ZERO(writeset);
1000 		FD_SET(sock, writeset);
1001 	}
1002 	if (evCmpTime(*finish, now) > 0)
1003 		timeout = evSubTime(*finish, now);
1004 	else
1005 		timeout = evConsTime(0L, 0L);
1006 
1007 	n = pselect(sock + 1, readset, writeset, NULL, &timeout, NULL);
1008 	if (n == 0) {
1009 		if (DBG) {
1010 			__libc_format_log(ANDROID_LOG_DEBUG, " libc",
1011 				"  %d retrying_select timeout\n", sock);
1012 		}
1013 		errno = ETIMEDOUT;
1014 		return 0;
1015 	}
1016 	if (n < 0) {
1017 		if (errno == EINTR)
1018 			goto retry;
1019 		if (DBG) {
1020 			__libc_format_log(ANDROID_LOG_DEBUG, "libc",
1021 				"  %d retrying_select got error %d\n",sock, n);
1022 		}
1023 		return n;
1024 	}
1025 	if ((readset && FD_ISSET(sock, readset)) || (writeset && FD_ISSET(sock, writeset))) {
1026 		len = sizeof(error);
1027 		if (getsockopt(sock, SOL_SOCKET, SO_ERROR, &error, &len) < 0 || error) {
1028 			errno = error;
1029 			if (DBG) {
1030 				__libc_format_log(ANDROID_LOG_DEBUG, "libc",
1031 					"  %d retrying_select dot error2 %d\n", sock, errno);
1032 			}
1033 
1034 			return -1;
1035 		}
1036 	}
1037 	if (DBG) {
1038 		__libc_format_log(ANDROID_LOG_DEBUG, "libc",
1039 			"  %d retrying_select returning %d\n",sock, n);
1040 	}
1041 
1042 	return n;
1043 }
1044 
1045 
1046 static int
send_dg(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz,int * terrno,int ns,int * v_circuit,int * gotsomewhere)1047 send_dg(res_state statp,
1048 	const u_char *buf, int buflen, u_char *ans, int anssiz,
1049 	int *terrno, int ns, int *v_circuit, int *gotsomewhere)
1050 {
1051 	const HEADER *hp = (const HEADER *)(const void *)buf;
1052 	HEADER *anhp = (HEADER *)(void *)ans;
1053 	const struct sockaddr *nsap;
1054 	int nsaplen;
1055 	struct timespec now, timeout, finish;
1056 	fd_set dsmask;
1057 	struct sockaddr_storage from;
1058 	socklen_t fromlen;
1059 	int resplen, seconds, n, s;
1060 
1061 	nsap = get_nsaddr(statp, (size_t)ns);
1062 	nsaplen = get_salen(nsap);
1063 	if (EXT(statp).nssocks[ns] == -1) {
1064 		EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
1065 		if (EXT(statp).nssocks[ns] > highestFD) {
1066 			res_nclose(statp);
1067 			errno = ENOTSOCK;
1068 		}
1069 		if (EXT(statp).nssocks[ns] < 0) {
1070 			switch (errno) {
1071 			case EPROTONOSUPPORT:
1072 #ifdef EPFNOSUPPORT
1073 			case EPFNOSUPPORT:
1074 #endif
1075 			case EAFNOSUPPORT:
1076 				Perror(statp, stderr, "socket(dg)", errno);
1077 				return (0);
1078 			default:
1079 				*terrno = errno;
1080 				Perror(statp, stderr, "socket(dg)", errno);
1081 				return (-1);
1082 			}
1083 		}
1084 
1085 		if (statp->_mark != MARK_UNSET) {
1086 			if (setsockopt(EXT(statp).nssocks[ns], SOL_SOCKET,
1087 					SO_MARK, &(statp->_mark), sizeof(statp->_mark)) < 0) {
1088 				res_nclose(statp);
1089 				return -1;
1090 			}
1091 		}
1092 #ifndef CANNOT_CONNECT_DGRAM
1093 		/*
1094 		 * On a 4.3BSD+ machine (client and server,
1095 		 * actually), sending to a nameserver datagram
1096 		 * port with no nameserver will cause an
1097 		 * ICMP port unreachable message to be returned.
1098 		 * If our datagram socket is "connected" to the
1099 		 * server, we get an ECONNREFUSED error on the next
1100 		 * socket operation, and select returns if the
1101 		 * error message is received.  We can thus detect
1102 		 * the absence of a nameserver without timing out.
1103 		 */
1104 		if (random_bind(EXT(statp).nssocks[ns], nsap->sa_family) < 0) {
1105 			Aerror(statp, stderr, "bind(dg)", errno, nsap,
1106 			    nsaplen);
1107 			res_nclose(statp);
1108 			return (0);
1109 		}
1110 		if (__connect(EXT(statp).nssocks[ns], nsap, (socklen_t)nsaplen) < 0) {
1111 			Aerror(statp, stderr, "connect(dg)", errno, nsap,
1112 			    nsaplen);
1113 			res_nclose(statp);
1114 			return (0);
1115 		}
1116 #endif /* !CANNOT_CONNECT_DGRAM */
1117 		Dprint(statp->options & RES_DEBUG,
1118 		       (stdout, ";; new DG socket\n"))
1119 
1120 	}
1121 	s = EXT(statp).nssocks[ns];
1122 #ifndef CANNOT_CONNECT_DGRAM
1123 	if (send(s, (const char*)buf, (size_t)buflen, 0) != buflen) {
1124 		Perror(statp, stderr, "send", errno);
1125 		res_nclose(statp);
1126 		return (0);
1127 	}
1128 #else /* !CANNOT_CONNECT_DGRAM */
1129 	if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen)
1130 	{
1131 		Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
1132 		res_nclose(statp);
1133 		return (0);
1134 	}
1135 #endif /* !CANNOT_CONNECT_DGRAM */
1136 
1137 	/*
1138 	 * Wait for reply.
1139 	 */
1140 	seconds = get_timeout(statp, ns);
1141 	now = evNowTime();
1142 	timeout = evConsTime((long)seconds, 0L);
1143 	finish = evAddTime(now, timeout);
1144 retry:
1145 	n = retrying_select(s, &dsmask, NULL, &finish);
1146 
1147 	if (n == 0) {
1148 		Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
1149 		*gotsomewhere = 1;
1150 		return (0);
1151 	}
1152 	if (n < 0) {
1153 		Perror(statp, stderr, "select", errno);
1154 		res_nclose(statp);
1155 		return (0);
1156 	}
1157 	errno = 0;
1158 	fromlen = sizeof(from);
1159 	resplen = recvfrom(s, (char*)ans, (size_t)anssiz,0,
1160 			   (struct sockaddr *)(void *)&from, &fromlen);
1161 	if (resplen <= 0) {
1162 		Perror(statp, stderr, "recvfrom", errno);
1163 		res_nclose(statp);
1164 		return (0);
1165 	}
1166 	*gotsomewhere = 1;
1167 	if (resplen < HFIXEDSZ) {
1168 		/*
1169 		 * Undersized message.
1170 		 */
1171 		Dprint(statp->options & RES_DEBUG,
1172 		       (stdout, ";; undersized: %d\n",
1173 			resplen));
1174 		*terrno = EMSGSIZE;
1175 		res_nclose(statp);
1176 		return (0);
1177 	}
1178 	if (hp->id != anhp->id) {
1179 		/*
1180 		 * response from old query, ignore it.
1181 		 * XXX - potential security hazard could
1182 		 *	 be detected here.
1183 		 */
1184 #ifdef ANDROID_CHANGES
1185 		__libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_OLD_RESPONSE);
1186 #endif
1187 		DprintQ((statp->options & RES_DEBUG) ||
1188 			(statp->pfcode & RES_PRF_REPLY),
1189 			(stdout, ";; old answer:\n"),
1190 			ans, (resplen > anssiz) ? anssiz : resplen);
1191 		goto retry;
1192 	}
1193 	if (!(statp->options & RES_INSECURE1) &&
1194 	    !res_ourserver_p(statp, (struct sockaddr *)(void *)&from)) {
1195 		/*
1196 		 * response from wrong server? ignore it.
1197 		 * XXX - potential security hazard could
1198 		 *	 be detected here.
1199 		 */
1200 #ifdef ANDROID_CHANGES
1201 		__libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_WRONG_SERVER);
1202 #endif
1203 		DprintQ((statp->options & RES_DEBUG) ||
1204 			(statp->pfcode & RES_PRF_REPLY),
1205 			(stdout, ";; not our server:\n"),
1206 			ans, (resplen > anssiz) ? anssiz : resplen);
1207 		goto retry;
1208 	}
1209 #ifdef RES_USE_EDNS0
1210 	if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) {
1211 		/*
1212 		 * Do not retry if the server do not understand EDNS0.
1213 		 * The case has to be captured here, as FORMERR packet do not
1214 		 * carry query section, hence res_queriesmatch() returns 0.
1215 		 */
1216 		DprintQ(statp->options & RES_DEBUG,
1217 			(stdout, "server rejected query with EDNS0:\n"),
1218 			ans, (resplen > anssiz) ? anssiz : resplen);
1219 		/* record the error */
1220 		statp->_flags |= RES_F_EDNS0ERR;
1221 		res_nclose(statp);
1222 		return (0);
1223 	}
1224 #endif
1225 	if (!(statp->options & RES_INSECURE2) &&
1226 	    !res_queriesmatch(buf, buf + buflen,
1227 			      ans, ans + anssiz)) {
1228 		/*
1229 		 * response contains wrong query? ignore it.
1230 		 * XXX - potential security hazard could
1231 		 *	 be detected here.
1232 		 */
1233 #ifdef ANDROID_CHANGES
1234 		__libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_WRONG_QUERY);
1235 #endif
1236 		DprintQ((statp->options & RES_DEBUG) ||
1237 			(statp->pfcode & RES_PRF_REPLY),
1238 			(stdout, ";; wrong query name:\n"),
1239 			ans, (resplen > anssiz) ? anssiz : resplen);
1240 		goto retry;;
1241 	}
1242 	if (anhp->rcode == SERVFAIL ||
1243 	    anhp->rcode == NOTIMP ||
1244 	    anhp->rcode == REFUSED) {
1245 		DprintQ(statp->options & RES_DEBUG,
1246 			(stdout, "server rejected query:\n"),
1247 			ans, (resplen > anssiz) ? anssiz : resplen);
1248 		res_nclose(statp);
1249 		/* don't retry if called from dig */
1250 		if (!statp->pfcode)
1251 			return (0);
1252 	}
1253 	if (!(statp->options & RES_IGNTC) && anhp->tc) {
1254 		/*
1255 		 * To get the rest of answer,
1256 		 * use TCP with same server.
1257 		 */
1258 		Dprint(statp->options & RES_DEBUG,
1259 		       (stdout, ";; truncated answer\n"));
1260 		*v_circuit = 1;
1261 		res_nclose(statp);
1262 		return (1);
1263 	}
1264 	/*
1265 	 * All is well, or the error is fatal.  Signal that the
1266 	 * next nameserver ought not be tried.
1267 	 */
1268 	return (resplen);
1269 }
1270 
1271 static void
Aerror(const res_state statp,FILE * file,const char * string,int error,const struct sockaddr * address,int alen)1272 Aerror(const res_state statp, FILE *file, const char *string, int error,
1273        const struct sockaddr *address, int alen)
1274 {
1275 	int save = errno;
1276 	char hbuf[NI_MAXHOST];
1277 	char sbuf[NI_MAXSERV];
1278 
1279 	if ((statp->options & RES_DEBUG) != 0U) {
1280 		if (getnameinfo(address, (socklen_t)alen, hbuf, sizeof(hbuf),
1281 		    sbuf, sizeof(sbuf), niflags)) {
1282 			strncpy(hbuf, "?", sizeof(hbuf) - 1);
1283 			hbuf[sizeof(hbuf) - 1] = '\0';
1284 			strncpy(sbuf, "?", sizeof(sbuf) - 1);
1285 			sbuf[sizeof(sbuf) - 1] = '\0';
1286 		}
1287 		fprintf(file, "res_send: %s ([%s].%s): %s\n",
1288 			string, hbuf, sbuf, strerror(error));
1289 	}
1290 	errno = save;
1291 }
1292 
1293 static void
Perror(const res_state statp,FILE * file,const char * string,int error)1294 Perror(const res_state statp, FILE *file, const char *string, int error) {
1295 	int save = errno;
1296 
1297 	if ((statp->options & RES_DEBUG) != 0U)
1298 		fprintf(file, "res_send: %s: %s\n",
1299 			string, strerror(error));
1300 	errno = save;
1301 }
1302 
1303 static int
sock_eq(struct sockaddr * a,struct sockaddr * b)1304 sock_eq(struct sockaddr *a, struct sockaddr *b) {
1305 	struct sockaddr_in *a4, *b4;
1306 	struct sockaddr_in6 *a6, *b6;
1307 
1308 	if (a->sa_family != b->sa_family)
1309 		return 0;
1310 	switch (a->sa_family) {
1311 	case AF_INET:
1312 		a4 = (struct sockaddr_in *)(void *)a;
1313 		b4 = (struct sockaddr_in *)(void *)b;
1314 		return a4->sin_port == b4->sin_port &&
1315 		    a4->sin_addr.s_addr == b4->sin_addr.s_addr;
1316 	case AF_INET6:
1317 		a6 = (struct sockaddr_in6 *)(void *)a;
1318 		b6 = (struct sockaddr_in6 *)(void *)b;
1319 		return a6->sin6_port == b6->sin6_port &&
1320 #ifdef HAVE_SIN6_SCOPE_ID
1321 		    a6->sin6_scope_id == b6->sin6_scope_id &&
1322 #endif
1323 		    IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr);
1324 	default:
1325 		return 0;
1326 	}
1327 }
1328 
1329 #ifdef NEED_PSELECT
1330 /* XXX needs to move to the porting library. */
1331 static int
pselect(int nfds,void * rfds,void * wfds,void * efds,struct timespec * tsp,const sigset_t * sigmask)1332 pselect(int nfds, void *rfds, void *wfds, void *efds,
1333 	struct timespec *tsp, const sigset_t *sigmask)
1334 {
1335 	struct timeval tv, *tvp;
1336 	sigset_t sigs;
1337 	int n;
1338 
1339 	if (tsp) {
1340 		tvp = &tv;
1341 		tv = evTimeVal(*tsp);
1342 	} else
1343 		tvp = NULL;
1344 	if (sigmask)
1345 		sigprocmask(SIG_SETMASK, sigmask, &sigs);
1346 	n = select(nfds, rfds, wfds, efds, tvp);
1347 	if (sigmask)
1348 		sigprocmask(SIG_SETMASK, &sigs, NULL);
1349 	if (tsp)
1350 		*tsp = evTimeSpec(tv);
1351 	return (n);
1352 }
1353 #endif
1354