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1 /* $NetBSD: getaddrinfo.c,v 1.82 2006/03/25 12:09:40 rpaulo 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 * This version of getaddrinfo.c is derived from Android 2.3 "Gingerbread",
35 * which contains uncredited changes by Android/Google developers. It has
36 * been modified in 2011 for use in the Android build of Mozilla Firefox by
37 * Mozilla contributors (including Michael Edwards <m.k.edwards@gmail.com>,
38 * and Steve Workman <sjhworkman@gmail.com>).
39 * These changes are offered under the same license as the original NetBSD
40 * file, whose copyright and license are unchanged above.
41 */
42 #define ANDROID_CHANGES 1
43 #define INET6 1
44
45 /*
46 * Issues to be discussed:
47 * - Return values. There are nonstandard return values defined and used
48 * in the source code. This is because RFC2553 is silent about which error
49 * code must be returned for which situation.
50 * - IPv4 classful (shortened) form. RFC2553 is silent about it. XNET 5.2
51 * says to use inet_aton() to convert IPv4 numeric to binary (alows
52 * classful form as a result).
53 * current code - disallow classful form for IPv4 (due to use of inet_pton).
54 * - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is
55 * invalid.
56 * current code - SEGV on freeaddrinfo(NULL)
57 * Note:
58 * - We use getipnodebyname() just for thread-safeness. There's no intent
59 * to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to
60 * getipnodebyname().
61 * - MOZILLA: Thread safeness for pre-Honeycomb Android versions implemented by
62 * way of open/gets/close and mmap rather than fopen/fgets/fclose. Affects
63 * _files_getaddrinfo for hosts file. Note: Honeycomb and later versions use
64 * a thread-safe stdio, so for those versions normal Bionic libc getaddrinfo
65 * is used.
66 * - The code filters out AFs that are not supported by the kernel,
67 * when globbing NULL hostname (to loopback, or wildcard). Is it the right
68 * thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG
69 * in ai_flags?
70 * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.
71 * (1) what should we do against numeric hostname (2) what should we do
72 * against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready?
73 * non-loopback address configured? global address configured?
74 * - To avoid search order issue, we have a big amount of code duplicate
75 * from gethnamaddr.c and some other places. The issues that there's no
76 * lower layer function to lookup "IPv4 or IPv6" record. Calling
77 * gethostbyname2 from getaddrinfo will end up in wrong search order, as
78 * follows:
79 * - The code makes use of following calls when asked to resolver with
80 * ai_family = PF_UNSPEC:
81 * getipnodebyname(host, AF_INET6);
82 * getipnodebyname(host, AF_INET);
83 * This will result in the following queries if the node is configure to
84 * prefer /etc/hosts than DNS:
85 * lookup /etc/hosts for IPv6 address
86 * lookup DNS for IPv6 address
87 * lookup /etc/hosts for IPv4 address
88 * lookup DNS for IPv4 address
89 * which may not meet people's requirement.
90 * The right thing to happen is to have underlying layer which does
91 * PF_UNSPEC lookup (lookup both) and return chain of addrinfos.
92 * This would result in a bit of code duplicate with _dns_ghbyname() and
93 * friends.
94 */
95
96 #include <fcntl.h>
97 #include <sys/cdefs.h>
98 #include <sys/types.h>
99 #include <sys/stat.h>
100 #include <sys/param.h>
101 #include <sys/socket.h>
102 #include <sys/un.h>
103 #include <sys/mman.h>
104 #include <net/if.h>
105 #include <netinet/in.h>
106 #include <arpa/inet.h>
107 #include "arpa_nameser.h"
108 #include <assert.h>
109 #include <ctype.h>
110 #include <errno.h>
111 #include <netdb.h>
112 #include "resolv_private.h"
113 #include <stddef.h>
114 #include <stdlib.h>
115 #include <string.h>
116 #include <unistd.h>
117
118 #include <syslog.h>
119 #include <stdarg.h>
120 #include "nsswitch.h"
121
122 #ifdef MOZ_GETADDRINFO_LOG_VERBOSE
123 #include <android/log.h>
124 #endif
125
126 #ifdef ANDROID_CHANGES
127 #include <sys/system_properties.h>
128 #endif /* ANDROID_CHANGES */
129
130 typedef struct _pseudo_FILE {
131 int fd;
132 off_t maplen;
133 void* mapping;
134 off_t offset;
135 } _pseudo_FILE;
136
137 #define _PSEUDO_FILE_INITIALIZER { -1, 0, MAP_FAILED, 0 }
138
139 static void
140 _pseudo_fclose(_pseudo_FILE * __restrict__ fp)
141 {
142 assert(fp);
143 fp->offset = 0;
144 if (fp->mapping != MAP_FAILED) {
145 (void) munmap(fp->mapping, fp->maplen);
146 fp->mapping = MAP_FAILED;
147 }
148 fp->maplen = 0;
149 if (fp->fd != -1) {
150 (void) close(fp->fd);
151 fp->fd = -1;
152 }
153 }
154
155 static _pseudo_FILE *
156 _pseudo_fopen_r(_pseudo_FILE * __restrict__ fp, const char* fname)
157 {
158 struct stat statbuf;
159 assert(fp);
160 fp->fd = open(fname, O_RDONLY);
161 if (fp->fd < 0) {
162 fp->fd = -1;
163 return NULL;
164 }
165 if ((0 != fstat(fp->fd, &statbuf)) || (statbuf.st_size <= 0)) {
166 close(fp->fd);
167 fp->fd = -1;
168 return NULL;
169 }
170 fp->maplen = statbuf.st_size;
171 fp->mapping = mmap(NULL, fp->maplen, PROT_READ, MAP_PRIVATE, fp->fd, 0);
172 if (fp->mapping == MAP_FAILED) {
173 close(fp->fd);
174 fp->fd = -1;
175 return NULL;
176 }
177 fp->offset = 0;
178 return fp;
179 }
180
181 static void
182 _pseudo_rewind(_pseudo_FILE * __restrict__ fp)
183 {
184 assert(fp);
185 fp->offset = 0;
186 }
187
188 static char*
189 _pseudo_fgets(char* buf, int bufsize, _pseudo_FILE * __restrict__ fp)
190 {
191 char* current;
192 char* endp;
193 int maxcopy;
194 assert(fp);
195 maxcopy = fp->maplen - fp->offset;
196 if (fp->mapping == MAP_FAILED)
197 return NULL;
198 if (maxcopy > bufsize - 1)
199 maxcopy = bufsize - 1;
200 if (maxcopy <= 0)
201 return NULL;
202 current = ((char*) fp->mapping) + fp->offset;
203 endp = memccpy(buf, current, '\n', maxcopy);
204 if (endp)
205 maxcopy = endp - buf;
206 buf[maxcopy] = '\0';
207 fp->offset += maxcopy;
208 return buf;
209 }
210
211 typedef union sockaddr_union {
212 struct sockaddr generic;
213 struct sockaddr_in in;
214 struct sockaddr_in6 in6;
215 } sockaddr_union;
216
217 #define SUCCESS 0
218 #define ANY 0
219 #define YES 1
220 #define NO 0
221
222 static const char in_addrany[] = { 0, 0, 0, 0 };
223 static const char in_loopback[] = { 127, 0, 0, 1 };
224 #ifdef INET6
225 static const char in6_addrany[] = {
226 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
227 };
228 static const char in6_loopback[] = {
229 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
230 };
231 #endif
232
233 static const struct afd {
234 int a_af;
235 int a_addrlen;
236 int a_socklen;
237 int a_off;
238 const char *a_addrany;
239 const char *a_loopback;
240 int a_scoped;
241 } afdl [] = {
242 #ifdef INET6
243 {PF_INET6, sizeof(struct in6_addr),
244 sizeof(struct sockaddr_in6),
245 offsetof(struct sockaddr_in6, sin6_addr),
246 in6_addrany, in6_loopback, 1},
247 #endif
248 {PF_INET, sizeof(struct in_addr),
249 sizeof(struct sockaddr_in),
250 offsetof(struct sockaddr_in, sin_addr),
251 in_addrany, in_loopback, 0},
252 {0, 0, 0, 0, NULL, NULL, 0},
253 };
254
255 struct explore {
256 int e_af;
257 int e_socktype;
258 int e_protocol;
259 const char *e_protostr;
260 int e_wild;
261 #define WILD_AF(ex) ((ex)->e_wild & 0x01)
262 #define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02)
263 #define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04)
264 };
265
266 static const struct explore explore[] = {
267 #if 0
268 { PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
269 #endif
270 #ifdef INET6
271 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
272 { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
273 { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 },
274 #endif
275 { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
276 { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
277 { PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
278 { PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
279 { PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
280 { PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 },
281 { -1, 0, 0, NULL, 0 },
282 };
283
284 #ifdef INET6
285 #define PTON_MAX 16
286 #else
287 #define PTON_MAX 4
288 #endif
289
290 static const ns_src default_dns_files[] = {
291 { NSSRC_FILES, NS_SUCCESS },
292 { NSSRC_DNS, NS_SUCCESS },
293 { 0, 0 }
294 };
295
296 #define MAXPACKET (64*1024)
297
298 typedef union {
299 HEADER hdr;
300 u_char buf[MAXPACKET];
301 } querybuf;
302
303 struct res_target {
304 struct res_target *next;
305 const char *name; /* domain name */
306 int qclass, qtype; /* class and type of query */
307 u_char *answer; /* buffer to put answer */
308 int anslen; /* size of answer buffer */
309 int n; /* result length */
310 };
311
312 static int str2number(const char *);
313 static int explore_fqdn(const struct addrinfo *, const char *,
314 const char *, struct addrinfo **);
315 static int explore_null(const struct addrinfo *,
316 const char *, struct addrinfo **);
317 static int explore_numeric(const struct addrinfo *, const char *,
318 const char *, struct addrinfo **, const char *);
319 static int explore_numeric_scope(const struct addrinfo *, const char *,
320 const char *, struct addrinfo **);
321 static int get_canonname(const struct addrinfo *,
322 struct addrinfo *, const char *);
323 static struct addrinfo *get_ai(const struct addrinfo *,
324 const struct afd *, const char *);
325 static int get_portmatch(const struct addrinfo *, const char *);
326 static int get_port(const struct addrinfo *, const char *, int);
327 static const struct afd *find_afd(int);
328 #ifdef INET6
329 static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *);
330 #endif
331
332 static struct addrinfo *getanswer(const querybuf *, int, const char *, int,
333 const struct addrinfo *);
334 static int _dns_getaddrinfo(void *, void *, va_list);
335 static void _sethtent(_pseudo_FILE * __restrict__);
336 static void _endhtent(_pseudo_FILE * __restrict__);
337 static struct addrinfo *_gethtent(_pseudo_FILE * __restrict__, const char *,
338 const struct addrinfo *);
339 static int _files_getaddrinfo(void *, void *, va_list);
340
341 static int res_queryN(const char *, struct res_target *, res_state);
342 static int res_searchN(const char *, struct res_target *, res_state);
343 static int res_querydomainN(const char *, const char *,
344 struct res_target *, res_state);
345
346 static const char * const ai_errlist[] = {
347 "Success",
348 "Address family for hostname not supported", /* EAI_ADDRFAMILY */
349 "Temporary failure in name resolution", /* EAI_AGAIN */
350 "Invalid value for ai_flags", /* EAI_BADFLAGS */
351 "Non-recoverable failure in name resolution", /* EAI_FAIL */
352 "ai_family not supported", /* EAI_FAMILY */
353 "Memory allocation failure", /* EAI_MEMORY */
354 "No address associated with hostname", /* EAI_NODATA */
355 "hostname nor servname provided, or not known", /* EAI_NONAME */
356 "servname not supported for ai_socktype", /* EAI_SERVICE */
357 "ai_socktype not supported", /* EAI_SOCKTYPE */
358 "System error returned in errno", /* EAI_SYSTEM */
359 "Invalid value for hints", /* EAI_BADHINTS */
360 "Resolved protocol is unknown", /* EAI_PROTOCOL */
361 "Argument buffer overflow", /* EAI_OVERFLOW */
362 "Unknown error", /* EAI_MAX */
363 };
364
365 /* XXX macros that make external reference is BAD. */
366
367 #define GET_AI(ai, afd, addr) \
368 do { \
369 /* external reference: pai, error, and label free */ \
370 (ai) = get_ai(pai, (afd), (addr)); \
371 if ((ai) == NULL) { \
372 error = EAI_MEMORY; \
373 goto free; \
374 } \
375 } while (/*CONSTCOND*/0)
376
377 #define GET_PORT(ai, serv) \
378 do { \
379 /* external reference: error and label free */ \
380 error = get_port((ai), (serv), 0); \
381 if (error != 0) \
382 goto free; \
383 } while (/*CONSTCOND*/0)
384
385 #define GET_CANONNAME(ai, str) \
386 do { \
387 /* external reference: pai, error and label free */ \
388 error = get_canonname(pai, (ai), (str)); \
389 if (error != 0) \
390 goto free; \
391 } while (/*CONSTCOND*/0)
392
393 #define ERR(err) \
394 do { \
395 /* external reference: error, and label bad */ \
396 error = (err); \
397 goto bad; \
398 /*NOTREACHED*/ \
399 } while (/*CONSTCOND*/0)
400
401 #define MATCH_FAMILY(x, y, w) \
402 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || \
403 (y) == PF_UNSPEC)))
404 #define MATCH(x, y, w) \
405 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
406
407 #pragma GCC visibility push(default)
408
409 extern const char *
410 __wrap_gai_strerror(int ecode);
411 extern void
412 __wrap_freeaddrinfo(struct addrinfo *ai);
413 extern int
414 __wrap_getaddrinfo(const char *hostname, const char *servname,
415 const struct addrinfo *hints, struct addrinfo **res);
416
417 int android_sdk_version;
418
419 #pragma GCC visibility pop
420
421 int android_sdk_version = -1;
422
423 static int honeycomb_or_later()
424 {
425 #ifdef MOZ_GETADDRINFO_LOG_VERBOSE
426 __android_log_print(ANDROID_LOG_INFO, "getaddrinfo",
427 "I am%s Honeycomb\n",
428 (android_sdk_version >= 11) ? "" : " not");
429 #endif
430 return android_sdk_version >= 11;
431 }
432
433 const char *
434 __wrap_gai_strerror(int ecode)
435 {
436 if (honeycomb_or_later())
437 return gai_strerror(ecode);
438 if (ecode < 0 || ecode > EAI_MAX)
439 ecode = EAI_MAX;
440 return ai_errlist[ecode];
441 }
442
443 void
444 __wrap_freeaddrinfo(struct addrinfo *ai)
445 {
446 struct addrinfo *next;
447
448 if (honeycomb_or_later()) {
449 freeaddrinfo(ai);
450 return;
451 }
452
453 assert(ai != NULL);
454
455 do {
456 next = ai->ai_next;
457 if (ai->ai_canonname)
458 free(ai->ai_canonname);
459 /* no need to free(ai->ai_addr) */
460 free(ai);
461 ai = next;
462 } while (ai);
463 }
464
465 static int
466 str2number(const char *p)
467 {
468 char *ep;
469 unsigned long v;
470
471 assert(p != NULL);
472
473 if (*p == '\0')
474 return -1;
475 ep = NULL;
476 errno = 0;
477 v = strtoul(p, &ep, 10);
478 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX)
479 return v;
480 else
481 return -1;
482 }
483
484 /*
485 * Connect a UDP socket to a given unicast address. This will cause no network
486 * traffic, but will fail fast if the system has no or limited reachability to
487 * the destination (e.g., no IPv4 address, no IPv6 default route, ...).
488 */
489 static int
490 _test_connect(int pf, struct sockaddr *addr, size_t addrlen) {
491 int s = socket(pf, SOCK_DGRAM, IPPROTO_UDP);
492 if (s < 0)
493 return 0;
494 int ret;
495 do {
496 ret = connect(s, addr, addrlen);
497 } while (ret < 0 && errno == EINTR);
498 int success = (ret == 0);
499 do {
500 ret = close(s);
501 } while (ret < 0 && errno == EINTR);
502 return success;
503 }
504
505 /*
506 * The following functions determine whether IPv4 or IPv6 connectivity is
507 * available in order to implement AI_ADDRCONFIG.
508 *
509 * Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is
510 * available, but whether addresses of the specified family are "configured
511 * on the local system". However, bionic doesn't currently support getifaddrs,
512 * so checking for connectivity is the next best thing.
513 */
514 static int
515 _have_ipv6() {
516 static const struct sockaddr_in6 sin6_test = {
517 .sin6_family = AF_INET6,
518 .sin6_addr.s6_addr = { // 2000::
519 0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
520 };
521 sockaddr_union addr = { .in6 = sin6_test };
522 return _test_connect(PF_INET6, &addr.generic, sizeof(addr.in6));
523 }
524
525 static int
526 _have_ipv4() {
527 static const struct sockaddr_in sin_test = {
528 .sin_family = AF_INET,
529 .sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8
530 };
531 sockaddr_union addr = { .in = sin_test };
532 return _test_connect(PF_INET, &addr.generic, sizeof(addr.in));
533 }
534
535 int
536 __wrap_getaddrinfo(const char *hostname, const char *servname,
537 const struct addrinfo *hints, struct addrinfo **res)
538 {
539 struct addrinfo sentinel;
540 struct addrinfo *cur;
541 int error = 0;
542 struct addrinfo ai;
543 struct addrinfo ai0;
544 struct addrinfo *pai;
545 const struct explore *ex;
546
547 if (honeycomb_or_later())
548 return getaddrinfo(hostname, servname, hints, res);
549
550 /* hostname is allowed to be NULL */
551 /* servname is allowed to be NULL */
552 /* hints is allowed to be NULL */
553 assert(res != NULL);
554
555 memset(&sentinel, 0, sizeof(sentinel));
556 cur = &sentinel;
557 pai = &ai;
558 pai->ai_flags = 0;
559 pai->ai_family = PF_UNSPEC;
560 pai->ai_socktype = ANY;
561 pai->ai_protocol = ANY;
562 pai->ai_addrlen = 0;
563 pai->ai_canonname = NULL;
564 pai->ai_addr = NULL;
565 pai->ai_next = NULL;
566
567 if (hostname == NULL && servname == NULL)
568 return EAI_NONAME;
569 if (hints) {
570 /* error check for hints */
571 if (hints->ai_addrlen || hints->ai_canonname ||
572 hints->ai_addr || hints->ai_next)
573 ERR(EAI_BADHINTS); /* xxx */
574 if (hints->ai_flags & ~AI_MASK)
575 ERR(EAI_BADFLAGS);
576 switch (hints->ai_family) {
577 case PF_UNSPEC:
578 case PF_INET:
579 #ifdef INET6
580 case PF_INET6:
581 #endif
582 break;
583 default:
584 ERR(EAI_FAMILY);
585 }
586 memcpy(pai, hints, sizeof(*pai));
587
588 /*
589 * if both socktype/protocol are specified, check if they
590 * are meaningful combination.
591 */
592 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
593 for (ex = explore; ex->e_af >= 0; ex++) {
594 if (pai->ai_family != ex->e_af)
595 continue;
596 if (ex->e_socktype == ANY)
597 continue;
598 if (ex->e_protocol == ANY)
599 continue;
600 if (pai->ai_socktype == ex->e_socktype
601 && pai->ai_protocol != ex->e_protocol) {
602 ERR(EAI_BADHINTS);
603 }
604 }
605 }
606 }
607
608 /*
609 * check for special cases. (1) numeric servname is disallowed if
610 * socktype/protocol are left unspecified. (2) servname is disallowed
611 * for raw and other inet{,6} sockets.
612 */
613 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
614 #ifdef PF_INET6
615 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
616 #endif
617 ) {
618 ai0 = *pai; /* backup *pai */
619
620 if (pai->ai_family == PF_UNSPEC) {
621 #ifdef PF_INET6
622 pai->ai_family = PF_INET6;
623 #else
624 pai->ai_family = PF_INET;
625 #endif
626 }
627 error = get_portmatch(pai, servname);
628 if (error)
629 ERR(error);
630
631 *pai = ai0;
632 }
633
634 ai0 = *pai;
635
636 /* NULL hostname, or numeric hostname */
637 for (ex = explore; ex->e_af >= 0; ex++) {
638 *pai = ai0;
639
640 /* PF_UNSPEC entries are prepared for DNS queries only */
641 if (ex->e_af == PF_UNSPEC)
642 continue;
643
644 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
645 continue;
646 if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
647 continue;
648 if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
649 continue;
650
651 if (pai->ai_family == PF_UNSPEC)
652 pai->ai_family = ex->e_af;
653 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
654 pai->ai_socktype = ex->e_socktype;
655 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
656 pai->ai_protocol = ex->e_protocol;
657
658 if (hostname == NULL)
659 error = explore_null(pai, servname, &cur->ai_next);
660 else
661 error = explore_numeric_scope(pai, hostname, servname,
662 &cur->ai_next);
663
664 if (error)
665 goto free;
666
667 while (cur->ai_next)
668 cur = cur->ai_next;
669 }
670
671 /*
672 * XXX
673 * If numeric representation of AF1 can be interpreted as FQDN
674 * representation of AF2, we need to think again about the code below.
675 */
676 if (sentinel.ai_next)
677 goto good;
678
679 if (hostname == NULL)
680 ERR(EAI_NODATA);
681 if (pai->ai_flags & AI_NUMERICHOST)
682 ERR(EAI_NONAME);
683
684 /*
685 * hostname as alphabetical name.
686 * we would like to prefer AF_INET6 than AF_INET, so we'll make a
687 * outer loop by AFs.
688 */
689 for (ex = explore; ex->e_af >= 0; ex++) {
690 *pai = ai0;
691
692 /* require exact match for family field */
693 if (pai->ai_family != ex->e_af)
694 continue;
695
696 if (!MATCH(pai->ai_socktype, ex->e_socktype,
697 WILD_SOCKTYPE(ex))) {
698 continue;
699 }
700 if (!MATCH(pai->ai_protocol, ex->e_protocol,
701 WILD_PROTOCOL(ex))) {
702 continue;
703 }
704
705 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
706 pai->ai_socktype = ex->e_socktype;
707 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
708 pai->ai_protocol = ex->e_protocol;
709
710 error = explore_fqdn(pai, hostname, servname,
711 &cur->ai_next);
712
713 while (cur && cur->ai_next)
714 cur = cur->ai_next;
715 }
716
717 /* XXX */
718 if (sentinel.ai_next)
719 error = 0;
720
721 if (error)
722 goto free;
723 if (error == 0) {
724 if (sentinel.ai_next) {
725 good:
726 *res = sentinel.ai_next;
727 return SUCCESS;
728 } else
729 error = EAI_FAIL;
730 }
731 free:
732 bad:
733 if (sentinel.ai_next)
734 __wrap_freeaddrinfo(sentinel.ai_next);
735 *res = NULL;
736 return error;
737 }
738
739 /*
740 * FQDN hostname, DNS lookup
741 */
742 static int
743 explore_fqdn(const struct addrinfo *pai, const char *hostname,
744 const char *servname, struct addrinfo **res)
745 {
746 struct addrinfo *result;
747 struct addrinfo *cur;
748 int error = 0;
749 static const ns_dtab dtab[] = {
750 NS_FILES_CB(_files_getaddrinfo, NULL)
751 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
752 NS_NIS_CB(_yp_getaddrinfo, NULL)
753 { 0, 0, 0 }
754 };
755
756 assert(pai != NULL);
757 /* hostname may be NULL */
758 /* servname may be NULL */
759 assert(res != NULL);
760
761 result = NULL;
762
763 /*
764 * if the servname does not match socktype/protocol, ignore it.
765 */
766 if (get_portmatch(pai, servname) != 0)
767 return 0;
768
769 switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
770 default_dns_files, hostname, pai)) {
771 case NS_TRYAGAIN:
772 error = EAI_AGAIN;
773 goto free;
774 case NS_UNAVAIL:
775 error = EAI_FAIL;
776 goto free;
777 case NS_NOTFOUND:
778 error = EAI_NODATA;
779 goto free;
780 case NS_SUCCESS:
781 error = 0;
782 for (cur = result; cur; cur = cur->ai_next) {
783 GET_PORT(cur, servname);
784 /* canonname should be filled already */
785 }
786 break;
787 }
788
789 *res = result;
790
791 return 0;
792
793 free:
794 if (result)
795 __wrap_freeaddrinfo(result);
796 return error;
797 }
798
799 /*
800 * hostname == NULL.
801 * passive socket -> anyaddr (0.0.0.0 or ::)
802 * non-passive socket -> localhost (127.0.0.1 or ::1)
803 */
804 static int
805 explore_null(const struct addrinfo *pai, const char *servname,
806 struct addrinfo **res)
807 {
808 int s;
809 const struct afd *afd;
810 struct addrinfo *cur;
811 struct addrinfo sentinel;
812 int error;
813
814 assert(pai != NULL);
815 /* servname may be NULL */
816 assert(res != NULL);
817
818 *res = NULL;
819 sentinel.ai_next = NULL;
820 cur = &sentinel;
821
822 /*
823 * filter out AFs that are not supported by the kernel
824 * XXX errno?
825 */
826 s = socket(pai->ai_family, SOCK_DGRAM, 0);
827 if (s < 0) {
828 if (errno != EMFILE)
829 return 0;
830 } else
831 close(s);
832
833 /*
834 * if the servname does not match socktype/protocol, ignore it.
835 */
836 if (get_portmatch(pai, servname) != 0)
837 return 0;
838
839 afd = find_afd(pai->ai_family);
840 if (afd == NULL)
841 return 0;
842
843 if (pai->ai_flags & AI_PASSIVE) {
844 GET_AI(cur->ai_next, afd, afd->a_addrany);
845 /* xxx meaningless?
846 * GET_CANONNAME(cur->ai_next, "anyaddr");
847 */
848 GET_PORT(cur->ai_next, servname);
849 } else {
850 GET_AI(cur->ai_next, afd, afd->a_loopback);
851 /* xxx meaningless?
852 * GET_CANONNAME(cur->ai_next, "localhost");
853 */
854 GET_PORT(cur->ai_next, servname);
855 }
856 cur = cur->ai_next;
857
858 *res = sentinel.ai_next;
859 return 0;
860
861 free:
862 if (sentinel.ai_next)
863 __wrap_freeaddrinfo(sentinel.ai_next);
864 return error;
865 }
866
867 /*
868 * numeric hostname
869 */
870 static int
871 explore_numeric(const struct addrinfo *pai, const char *hostname,
872 const char *servname, struct addrinfo **res, const char *canonname)
873 {
874 const struct afd *afd;
875 struct addrinfo *cur;
876 struct addrinfo sentinel;
877 int error;
878 char pton[PTON_MAX];
879
880 assert(pai != NULL);
881 /* hostname may be NULL */
882 /* servname may be NULL */
883 assert(res != NULL);
884
885 *res = NULL;
886 sentinel.ai_next = NULL;
887 cur = &sentinel;
888
889 /*
890 * if the servname does not match socktype/protocol, ignore it.
891 */
892 if (get_portmatch(pai, servname) != 0)
893 return 0;
894
895 afd = find_afd(pai->ai_family);
896 if (afd == NULL)
897 return 0;
898
899 switch (afd->a_af) {
900 #if 0 /*X/Open spec*/
901 case AF_INET:
902 if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
903 if (pai->ai_family == afd->a_af ||
904 pai->ai_family == PF_UNSPEC /*?*/) {
905 GET_AI(cur->ai_next, afd, pton);
906 GET_PORT(cur->ai_next, servname);
907 if ((pai->ai_flags & AI_CANONNAME)) {
908 /*
909 * Set the numeric address itself as
910 * the canonical name, based on a
911 * clarification in rfc2553bis-03.
912 */
913 GET_CANONNAME(cur->ai_next, canonname);
914 }
915 while (cur && cur->ai_next)
916 cur = cur->ai_next;
917 } else
918 ERR(EAI_FAMILY); /*xxx*/
919 }
920 break;
921 #endif
922 default:
923 if (inet_pton(afd->a_af, hostname, pton) == 1) {
924 if (pai->ai_family == afd->a_af ||
925 pai->ai_family == PF_UNSPEC /*?*/) {
926 GET_AI(cur->ai_next, afd, pton);
927 GET_PORT(cur->ai_next, servname);
928 if ((pai->ai_flags & AI_CANONNAME)) {
929 /*
930 * Set the numeric address itself as
931 * the canonical name, based on a
932 * clarification in rfc2553bis-03.
933 */
934 GET_CANONNAME(cur->ai_next, canonname);
935 }
936 while (cur->ai_next)
937 cur = cur->ai_next;
938 } else
939 ERR(EAI_FAMILY); /*xxx*/
940 }
941 break;
942 }
943
944 *res = sentinel.ai_next;
945 return 0;
946
947 free:
948 bad:
949 if (sentinel.ai_next)
950 __wrap_freeaddrinfo(sentinel.ai_next);
951 return error;
952 }
953
954 /*
955 * numeric hostname with scope
956 */
957 static int
958 explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
959 const char *servname, struct addrinfo **res)
960 {
961 #if !defined(SCOPE_DELIMITER) || !defined(INET6)
962 return explore_numeric(pai, hostname, servname, res, hostname);
963 #else
964 const struct afd *afd;
965 struct addrinfo *cur;
966 int error;
967 char *cp, *hostname2 = NULL, *scope, *addr;
968 struct sockaddr_in6 *sin6;
969
970 assert(pai != NULL);
971 /* hostname may be NULL */
972 /* servname may be NULL */
973 assert(res != NULL);
974
975 /*
976 * if the servname does not match socktype/protocol, ignore it.
977 */
978 if (get_portmatch(pai, servname) != 0)
979 return 0;
980
981 afd = find_afd(pai->ai_family);
982 if (afd == NULL)
983 return 0;
984
985 if (!afd->a_scoped)
986 return explore_numeric(pai, hostname, servname, res, hostname);
987
988 cp = strchr(hostname, SCOPE_DELIMITER);
989 if (cp == NULL)
990 return explore_numeric(pai, hostname, servname, res, hostname);
991
992 /*
993 * Handle special case of <scoped_address><delimiter><scope id>
994 */
995 hostname2 = strdup(hostname);
996 if (hostname2 == NULL)
997 return EAI_MEMORY;
998 /* terminate at the delimiter */
999 hostname2[cp - hostname] = '\0';
1000 addr = hostname2;
1001 scope = cp + 1;
1002
1003 error = explore_numeric(pai, addr, servname, res, hostname);
1004 if (error == 0) {
1005 u_int32_t scopeid;
1006
1007 for (cur = *res; cur; cur = cur->ai_next) {
1008 if (cur->ai_family != AF_INET6)
1009 continue;
1010 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
1011 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
1012 free(hostname2);
1013 return(EAI_NODATA); /* XXX: is return OK? */
1014 }
1015 sin6->sin6_scope_id = scopeid;
1016 }
1017 }
1018
1019 free(hostname2);
1020
1021 return error;
1022 #endif
1023 }
1024
1025 static int
1026 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
1027 {
1028
1029 assert(pai != NULL);
1030 assert(ai != NULL);
1031 assert(str != NULL);
1032
1033 if ((pai->ai_flags & AI_CANONNAME) != 0) {
1034 ai->ai_canonname = strdup(str);
1035 if (ai->ai_canonname == NULL)
1036 return EAI_MEMORY;
1037 }
1038 return 0;
1039 }
1040
1041 static struct addrinfo *
1042 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
1043 {
1044 char *p;
1045 struct addrinfo *ai;
1046
1047 assert(pai != NULL);
1048 assert(afd != NULL);
1049 assert(addr != NULL);
1050
1051 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
1052 + (afd->a_socklen));
1053 if (ai == NULL)
1054 return NULL;
1055
1056 memcpy(ai, pai, sizeof(struct addrinfo));
1057 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1058 memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1059
1060 #ifdef HAVE_SA_LEN
1061 ai->ai_addr->sa_len = afd->a_socklen;
1062 #endif
1063
1064 ai->ai_addrlen = afd->a_socklen;
1065 #if defined (__alpha__) || (defined(__i386__) && defined(_LP64)) || defined(__sparc64__)
1066 ai->__ai_pad0 = 0;
1067 #endif
1068 ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1069 p = (char *)(void *)(ai->ai_addr);
1070 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
1071 return ai;
1072 }
1073
1074 static int
1075 get_portmatch(const struct addrinfo *ai, const char *servname)
1076 {
1077
1078 assert(ai != NULL);
1079 /* servname may be NULL */
1080
1081 return get_port(ai, servname, 1);
1082 }
1083
1084 static int
1085 get_port(const struct addrinfo *ai, const char *servname, int matchonly)
1086 {
1087 const char *proto;
1088 struct servent *sp;
1089 int port;
1090 int allownumeric;
1091
1092 assert(ai != NULL);
1093 /* servname may be NULL */
1094
1095 if (servname == NULL)
1096 return 0;
1097 switch (ai->ai_family) {
1098 case AF_INET:
1099 #ifdef AF_INET6
1100 case AF_INET6:
1101 #endif
1102 break;
1103 default:
1104 return 0;
1105 }
1106
1107 switch (ai->ai_socktype) {
1108 case SOCK_RAW:
1109 return EAI_SERVICE;
1110 case SOCK_DGRAM:
1111 case SOCK_STREAM:
1112 allownumeric = 1;
1113 break;
1114 case ANY:
1115 #if 1 /* ANDROID-SPECIFIC CHANGE TO MATCH GLIBC */
1116 allownumeric = 1;
1117 #else
1118 allownumeric = 0;
1119 #endif
1120 break;
1121 default:
1122 return EAI_SOCKTYPE;
1123 }
1124
1125 port = str2number(servname);
1126 if (port >= 0) {
1127 if (!allownumeric)
1128 return EAI_SERVICE;
1129 if (port < 0 || port > 65535)
1130 return EAI_SERVICE;
1131 port = htons(port);
1132 } else {
1133 if (ai->ai_flags & AI_NUMERICSERV)
1134 return EAI_NONAME;
1135
1136 switch (ai->ai_socktype) {
1137 case SOCK_DGRAM:
1138 proto = "udp";
1139 break;
1140 case SOCK_STREAM:
1141 proto = "tcp";
1142 break;
1143 default:
1144 proto = NULL;
1145 break;
1146 }
1147
1148 if ((sp = getservbyname(servname, proto)) == NULL)
1149 return EAI_SERVICE;
1150 port = sp->s_port;
1151 }
1152
1153 if (!matchonly) {
1154 switch (ai->ai_family) {
1155 case AF_INET:
1156 ((struct sockaddr_in *)(void *)
1157 ai->ai_addr)->sin_port = port;
1158 break;
1159 #ifdef INET6
1160 case AF_INET6:
1161 ((struct sockaddr_in6 *)(void *)
1162 ai->ai_addr)->sin6_port = port;
1163 break;
1164 #endif
1165 }
1166 }
1167
1168 return 0;
1169 }
1170
1171 static const struct afd *
1172 find_afd(int af)
1173 {
1174 const struct afd *afd;
1175
1176 if (af == PF_UNSPEC)
1177 return NULL;
1178 for (afd = afdl; afd->a_af; afd++) {
1179 if (afd->a_af == af)
1180 return afd;
1181 }
1182 return NULL;
1183 }
1184
1185 #ifdef INET6
1186 /* convert a string to a scope identifier. XXX: IPv6 specific */
1187 static int
1188 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
1189 {
1190 u_long lscopeid;
1191 struct in6_addr *a6;
1192 char *ep;
1193
1194 assert(scope != NULL);
1195 assert(sin6 != NULL);
1196 assert(scopeid != NULL);
1197
1198 a6 = &sin6->sin6_addr;
1199
1200 /* empty scopeid portion is invalid */
1201 if (*scope == '\0')
1202 return -1;
1203
1204 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
1205 /*
1206 * We currently assume a one-to-one mapping between links
1207 * and interfaces, so we simply use interface indices for
1208 * like-local scopes.
1209 */
1210 *scopeid = if_nametoindex(scope);
1211 if (*scopeid == 0)
1212 goto trynumeric;
1213 return 0;
1214 }
1215
1216 /* still unclear about literal, allow numeric only - placeholder */
1217 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1218 goto trynumeric;
1219 if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1220 goto trynumeric;
1221 else
1222 goto trynumeric; /* global */
1223
1224 /* try to convert to a numeric id as a last resort */
1225 trynumeric:
1226 errno = 0;
1227 lscopeid = strtoul(scope, &ep, 10);
1228 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
1229 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
1230 return 0;
1231 else
1232 return -1;
1233 }
1234 #endif
1235
1236 /* code duplicate with gethnamaddr.c */
1237
1238 static const char AskedForGot[] =
1239 "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1240
1241 static struct addrinfo *
1242 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
1243 const struct addrinfo *pai)
1244 {
1245 struct addrinfo sentinel, *cur;
1246 struct addrinfo ai;
1247 const struct afd *afd;
1248 char *canonname;
1249 const HEADER *hp;
1250 const u_char *cp;
1251 int n;
1252 const u_char *eom;
1253 char *bp, *ep;
1254 int type, class, ancount, qdcount;
1255 int haveanswer, had_error;
1256 char tbuf[MAXDNAME];
1257 int (*name_ok) (const char *);
1258 char hostbuf[8*1024];
1259
1260 assert(answer != NULL);
1261 assert(qname != NULL);
1262 assert(pai != NULL);
1263
1264 memset(&sentinel, 0, sizeof(sentinel));
1265 cur = &sentinel;
1266
1267 canonname = NULL;
1268 eom = answer->buf + anslen;
1269 switch (qtype) {
1270 case T_A:
1271 case T_AAAA:
1272 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
1273 name_ok = res_hnok;
1274 break;
1275 default:
1276 return NULL; /* XXX should be abort(); */
1277 }
1278 /*
1279 * find first satisfactory answer
1280 */
1281 hp = &answer->hdr;
1282 ancount = ntohs(hp->ancount);
1283 qdcount = ntohs(hp->qdcount);
1284 bp = hostbuf;
1285 ep = hostbuf + sizeof hostbuf;
1286 cp = answer->buf + HFIXEDSZ;
1287 if (qdcount != 1) {
1288 h_errno = NO_RECOVERY;
1289 return (NULL);
1290 }
1291 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
1292 if ((n < 0) || !(*name_ok)(bp)) {
1293 h_errno = NO_RECOVERY;
1294 return (NULL);
1295 }
1296 cp += n + QFIXEDSZ;
1297 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
1298 /* res_send() has already verified that the query name is the
1299 * same as the one we sent; this just gets the expanded name
1300 * (i.e., with the succeeding search-domain tacked on).
1301 */
1302 n = strlen(bp) + 1; /* for the \0 */
1303 if (n >= MAXHOSTNAMELEN) {
1304 h_errno = NO_RECOVERY;
1305 return (NULL);
1306 }
1307 canonname = bp;
1308 bp += n;
1309 /* The qname can be abbreviated, but h_name is now absolute. */
1310 qname = canonname;
1311 }
1312 haveanswer = 0;
1313 had_error = 0;
1314 while (ancount-- > 0 && cp < eom && !had_error) {
1315 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
1316 if ((n < 0) || !(*name_ok)(bp)) {
1317 had_error++;
1318 continue;
1319 }
1320 cp += n; /* name */
1321 type = _getshort(cp);
1322 cp += INT16SZ; /* type */
1323 class = _getshort(cp);
1324 cp += INT16SZ + INT32SZ; /* class, TTL */
1325 n = _getshort(cp);
1326 cp += INT16SZ; /* len */
1327 if (class != C_IN) {
1328 /* XXX - debug? syslog? */
1329 cp += n;
1330 continue; /* XXX - had_error++ ? */
1331 }
1332 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
1333 type == T_CNAME) {
1334 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
1335 if ((n < 0) || !(*name_ok)(tbuf)) {
1336 had_error++;
1337 continue;
1338 }
1339 cp += n;
1340 /* Get canonical name. */
1341 n = strlen(tbuf) + 1; /* for the \0 */
1342 if (n > ep - bp || n >= MAXHOSTNAMELEN) {
1343 had_error++;
1344 continue;
1345 }
1346 strlcpy(bp, tbuf, (size_t)(ep - bp));
1347 canonname = bp;
1348 bp += n;
1349 continue;
1350 }
1351 if (qtype == T_ANY) {
1352 if (!(type == T_A || type == T_AAAA)) {
1353 cp += n;
1354 continue;
1355 }
1356 } else if (type != qtype) {
1357 if (type != T_KEY && type != T_SIG)
1358 syslog(LOG_NOTICE|LOG_AUTH,
1359 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
1360 qname, p_class(C_IN), p_type(qtype),
1361 p_type(type));
1362 cp += n;
1363 continue; /* XXX - had_error++ ? */
1364 }
1365 switch (type) {
1366 case T_A:
1367 case T_AAAA:
1368 if (strcasecmp(canonname, bp) != 0) {
1369 syslog(LOG_NOTICE|LOG_AUTH,
1370 AskedForGot, canonname, bp);
1371 cp += n;
1372 continue; /* XXX - had_error++ ? */
1373 }
1374 if (type == T_A && n != INADDRSZ) {
1375 cp += n;
1376 continue;
1377 }
1378 if (type == T_AAAA && n != IN6ADDRSZ) {
1379 cp += n;
1380 continue;
1381 }
1382 if (type == T_AAAA) {
1383 struct in6_addr in6;
1384 memcpy(&in6, cp, IN6ADDRSZ);
1385 if (IN6_IS_ADDR_V4MAPPED(&in6)) {
1386 cp += n;
1387 continue;
1388 }
1389 }
1390 if (!haveanswer) {
1391 int nn;
1392
1393 canonname = bp;
1394 nn = strlen(bp) + 1; /* for the \0 */
1395 bp += nn;
1396 }
1397
1398 /* don't overwrite pai */
1399 ai = *pai;
1400 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
1401 afd = find_afd(ai.ai_family);
1402 if (afd == NULL) {
1403 cp += n;
1404 continue;
1405 }
1406 cur->ai_next = get_ai(&ai, afd, (const char *)cp);
1407 if (cur->ai_next == NULL)
1408 had_error++;
1409 while (cur && cur->ai_next)
1410 cur = cur->ai_next;
1411 cp += n;
1412 break;
1413 default:
1414 abort();
1415 }
1416 if (!had_error)
1417 haveanswer++;
1418 }
1419 if (haveanswer) {
1420 if (!canonname)
1421 (void)get_canonname(pai, sentinel.ai_next, qname);
1422 else
1423 (void)get_canonname(pai, sentinel.ai_next, canonname);
1424 h_errno = NETDB_SUCCESS;
1425 return sentinel.ai_next;
1426 }
1427
1428 h_errno = NO_RECOVERY;
1429 return NULL;
1430 }
1431
1432 struct addrinfo_sort_elem {
1433 struct addrinfo *ai;
1434 int has_src_addr;
1435 sockaddr_union src_addr;
1436 int original_order;
1437 };
1438
1439 /*ARGSUSED*/
1440 static int
1441 _get_scope(const struct sockaddr *addr)
1442 {
1443 if (addr->sa_family == AF_INET6) {
1444 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1445 if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) {
1446 return IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr);
1447 } else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) ||
1448 IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) {
1449 /*
1450 * RFC 4291 section 2.5.3 says loopback is to be treated as having
1451 * link-local scope.
1452 */
1453 return IPV6_ADDR_SCOPE_LINKLOCAL;
1454 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
1455 return IPV6_ADDR_SCOPE_SITELOCAL;
1456 } else {
1457 return IPV6_ADDR_SCOPE_GLOBAL;
1458 }
1459 } else if (addr->sa_family == AF_INET) {
1460 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
1461 unsigned long int na = ntohl(addr4->sin_addr.s_addr);
1462
1463 if (IN_LOOPBACK(na) || /* 127.0.0.0/8 */
1464 (na & 0xffff0000) == 0xa9fe0000) { /* 169.254.0.0/16 */
1465 return IPV6_ADDR_SCOPE_LINKLOCAL;
1466 } else {
1467 /*
1468 * According to draft-ietf-6man-rfc3484-revise-01 section 2.3,
1469 * it is best not to treat the private IPv4 ranges
1470 * (10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16) as being
1471 * in a special scope, so we don't.
1472 */
1473 return IPV6_ADDR_SCOPE_GLOBAL;
1474 }
1475 } else {
1476 /*
1477 * This should never happen.
1478 * Return a scope with low priority as a last resort.
1479 */
1480 return IPV6_ADDR_SCOPE_NODELOCAL;
1481 }
1482 }
1483
1484 /* These macros are modelled after the ones in <netinet/in6.h>. */
1485
1486 /* RFC 4380, section 2.6 */
1487 #define IN6_IS_ADDR_TEREDO(a) \
1488 ((*(const uint32_t *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000)))
1489
1490 /* RFC 3056, section 2. */
1491 #define IN6_IS_ADDR_6TO4(a) \
1492 (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02))
1493
1494 /* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */
1495 #define IN6_IS_ADDR_6BONE(a) \
1496 (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe))
1497
1498 /*
1499 * Get the label for a given IPv4/IPv6 address.
1500 * RFC 3484, section 2.1, plus changes from draft-ietf-6man-rfc3484-revise-01.
1501 */
1502
1503 /*ARGSUSED*/
1504 static int
1505 _get_label(const struct sockaddr *addr)
1506 {
1507 if (addr->sa_family == AF_INET) {
1508 return 3;
1509 } else if (addr->sa_family == AF_INET6) {
1510 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1511 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
1512 return 0;
1513 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
1514 return 3;
1515 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
1516 return 4;
1517 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
1518 return 5;
1519 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) {
1520 return 10;
1521 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
1522 return 11;
1523 } else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
1524 return 12;
1525 } else {
1526 return 2;
1527 }
1528 } else {
1529 /*
1530 * This should never happen.
1531 * Return a semi-random label as a last resort.
1532 */
1533 return 1;
1534 }
1535 }
1536
1537 /*
1538 * Get the precedence for a given IPv4/IPv6 address.
1539 * RFC 3484, section 2.1, plus changes from draft-ietf-6man-rfc3484-revise-01.
1540 */
1541
1542 /*ARGSUSED*/
1543 static int
1544 _get_precedence(const struct sockaddr *addr)
1545 {
1546 if (addr->sa_family == AF_INET) {
1547 return 30;
1548 } else if (addr->sa_family == AF_INET6) {
1549 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1550 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
1551 return 60;
1552 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
1553 return 30;
1554 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
1555 return 20;
1556 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
1557 return 10;
1558 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) ||
1559 IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) ||
1560 IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
1561 return 1;
1562 } else {
1563 return 40;
1564 }
1565 } else {
1566 return 1;
1567 }
1568 }
1569
1570 /*
1571 * Find number of matching initial bits between the two addresses a1 and a2.
1572 */
1573
1574 /*ARGSUSED*/
1575 static int
1576 _common_prefix_len(const struct in6_addr *a1, const struct in6_addr *a2)
1577 {
1578 const char *p1 = (const char *)a1;
1579 const char *p2 = (const char *)a2;
1580 unsigned i;
1581
1582 for (i = 0; i < sizeof(*a1); ++i) {
1583 int x, j;
1584
1585 if (p1[i] == p2[i]) {
1586 continue;
1587 }
1588 x = p1[i] ^ p2[i];
1589 for (j = 0; j < CHAR_BIT; ++j) {
1590 if (x & (1 << (CHAR_BIT - 1))) {
1591 return i * CHAR_BIT + j;
1592 }
1593 x <<= 1;
1594 }
1595 }
1596 return sizeof(*a1) * CHAR_BIT;
1597 }
1598
1599 /*
1600 * Compare two source/destination address pairs.
1601 * RFC 3484, section 6.
1602 */
1603
1604 /*ARGSUSED*/
1605 static int
1606 _rfc3484_compare(const void *ptr1, const void* ptr2)
1607 {
1608 const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1;
1609 const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2;
1610 int scope_src1, scope_dst1, scope_match1;
1611 int scope_src2, scope_dst2, scope_match2;
1612 int label_src1, label_dst1, label_match1;
1613 int label_src2, label_dst2, label_match2;
1614 int precedence1, precedence2;
1615 int prefixlen1, prefixlen2;
1616
1617 /* Rule 1: Avoid unusable destinations. */
1618 if (a1->has_src_addr != a2->has_src_addr) {
1619 return a2->has_src_addr - a1->has_src_addr;
1620 }
1621
1622 /* Rule 2: Prefer matching scope. */
1623 scope_src1 = _get_scope(&a1->src_addr.generic);
1624 scope_dst1 = _get_scope(a1->ai->ai_addr);
1625 scope_match1 = (scope_src1 == scope_dst1);
1626
1627 scope_src2 = _get_scope(&a2->src_addr.generic);
1628 scope_dst2 = _get_scope(a2->ai->ai_addr);
1629 scope_match2 = (scope_src2 == scope_dst2);
1630
1631 if (scope_match1 != scope_match2) {
1632 return scope_match2 - scope_match1;
1633 }
1634
1635 /*
1636 * Rule 3: Avoid deprecated addresses.
1637 * TODO(sesse): We don't currently have a good way of finding this.
1638 */
1639
1640 /*
1641 * Rule 4: Prefer home addresses.
1642 * TODO(sesse): We don't currently have a good way of finding this.
1643 */
1644
1645 /* Rule 5: Prefer matching label. */
1646 label_src1 = _get_label(&a1->src_addr.generic);
1647 label_dst1 = _get_label(a1->ai->ai_addr);
1648 label_match1 = (label_src1 == label_dst1);
1649
1650 label_src2 = _get_label(&a2->src_addr.generic);
1651 label_dst2 = _get_label(a2->ai->ai_addr);
1652 label_match2 = (label_src2 == label_dst2);
1653
1654 if (label_match1 != label_match2) {
1655 return label_match2 - label_match1;
1656 }
1657
1658 /* Rule 6: Prefer higher precedence. */
1659 precedence1 = _get_precedence(a1->ai->ai_addr);
1660 precedence2 = _get_precedence(a2->ai->ai_addr);
1661 if (precedence1 != precedence2) {
1662 return precedence2 - precedence1;
1663 }
1664
1665 /*
1666 * Rule 7: Prefer native transport.
1667 * TODO(sesse): We don't currently have a good way of finding this.
1668 */
1669
1670 /* Rule 8: Prefer smaller scope. */
1671 if (scope_dst1 != scope_dst2) {
1672 return scope_dst1 - scope_dst2;
1673 }
1674
1675 /*
1676 * Rule 9: Use longest matching prefix.
1677 * We implement this for IPv6 only, as the rules in RFC 3484 don't seem
1678 * to work very well directly applied to IPv4. (glibc uses information from
1679 * the routing table for a custom IPv4 implementation here.)
1680 */
1681 if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 &&
1682 a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6) {
1683 const struct sockaddr_in6 *a1_src = &a1->src_addr.in6;
1684 const struct sockaddr_in6 *a1_dst = (const struct sockaddr_in6 *)a1->ai->ai_addr;
1685 const struct sockaddr_in6 *a2_src = &a2->src_addr.in6;
1686 const struct sockaddr_in6 *a2_dst = (const struct sockaddr_in6 *)a2->ai->ai_addr;
1687 prefixlen1 = _common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr);
1688 prefixlen2 = _common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr);
1689 if (prefixlen1 != prefixlen2) {
1690 return prefixlen2 - prefixlen1;
1691 }
1692 }
1693
1694 /*
1695 * Rule 10: Leave the order unchanged.
1696 * We need this since qsort() is not necessarily stable.
1697 */
1698 return a1->original_order - a2->original_order;
1699 }
1700
1701 /*
1702 * Find the source address that will be used if trying to connect to the given
1703 * address. src_addr must be large enough to hold a struct sockaddr_in6.
1704 *
1705 * Returns 1 if a source address was found, 0 if the address is unreachable,
1706 * and -1 if a fatal error occurred. If 0 or 1, the contents of src_addr are
1707 * undefined.
1708 */
1709
1710 /*ARGSUSED*/
1711 static int
1712 _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr)
1713 {
1714 int sock;
1715 int ret;
1716 socklen_t len;
1717
1718 switch (addr->sa_family) {
1719 case AF_INET:
1720 len = sizeof(struct sockaddr_in);
1721 break;
1722 case AF_INET6:
1723 len = sizeof(struct sockaddr_in6);
1724 break;
1725 default:
1726 /* No known usable source address for non-INET families. */
1727 return 0;
1728 }
1729
1730 sock = socket(addr->sa_family, SOCK_DGRAM, IPPROTO_UDP);
1731 if (sock == -1) {
1732 if (errno == EAFNOSUPPORT) {
1733 return 0;
1734 } else {
1735 return -1;
1736 }
1737 }
1738
1739 do {
1740 ret = connect(sock, addr, len);
1741 } while (ret == -1 && errno == EINTR);
1742
1743 if (ret == -1) {
1744 close(sock);
1745 return 0;
1746 }
1747
1748 if (getsockname(sock, src_addr, &len) == -1) {
1749 close(sock);
1750 return -1;
1751 }
1752 close(sock);
1753 return 1;
1754 }
1755
1756 /*
1757 * Sort the linked list starting at sentinel->ai_next in RFC3484 order.
1758 * Will leave the list unchanged if an error occurs.
1759 */
1760
1761 /*ARGSUSED*/
1762 static void
1763 _rfc3484_sort(struct addrinfo *list_sentinel)
1764 {
1765 struct addrinfo *cur;
1766 int nelem = 0, i;
1767 struct addrinfo_sort_elem *elems;
1768
1769 cur = list_sentinel->ai_next;
1770 while (cur) {
1771 ++nelem;
1772 cur = cur->ai_next;
1773 }
1774
1775 elems = (struct addrinfo_sort_elem *)malloc(nelem * sizeof(struct addrinfo_sort_elem));
1776 if (elems == NULL) {
1777 goto error;
1778 }
1779
1780 /*
1781 * Convert the linked list to an array that also contains the candidate
1782 * source address for each destination address.
1783 */
1784 for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) {
1785 int has_src_addr;
1786 assert(cur != NULL);
1787 elems[i].ai = cur;
1788 elems[i].original_order = i;
1789
1790 has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic);
1791 if (has_src_addr == -1) {
1792 goto error;
1793 }
1794 elems[i].has_src_addr = has_src_addr;
1795 }
1796
1797 /* Sort the addresses, and rearrange the linked list so it matches the sorted order. */
1798 qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem), _rfc3484_compare);
1799
1800 list_sentinel->ai_next = elems[0].ai;
1801 for (i = 0; i < nelem - 1; ++i) {
1802 elems[i].ai->ai_next = elems[i + 1].ai;
1803 }
1804 elems[nelem - 1].ai->ai_next = NULL;
1805
1806 error:
1807 free(elems);
1808 }
1809
1810 /*ARGSUSED*/
1811 static int
1812 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
1813 {
1814 struct addrinfo *ai;
1815 querybuf *buf, *buf2;
1816 const char *name;
1817 const struct addrinfo *pai;
1818 struct addrinfo sentinel, *cur;
1819 struct res_target q, q2;
1820 res_state res;
1821
1822 name = va_arg(ap, char *);
1823 pai = va_arg(ap, const struct addrinfo *);
1824 //fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name);
1825
1826 memset(&q, 0, sizeof(q));
1827 memset(&q2, 0, sizeof(q2));
1828 memset(&sentinel, 0, sizeof(sentinel));
1829 cur = &sentinel;
1830
1831 buf = malloc(sizeof(*buf));
1832 if (buf == NULL) {
1833 h_errno = NETDB_INTERNAL;
1834 return NS_NOTFOUND;
1835 }
1836 buf2 = malloc(sizeof(*buf2));
1837 if (buf2 == NULL) {
1838 free(buf);
1839 h_errno = NETDB_INTERNAL;
1840 return NS_NOTFOUND;
1841 }
1842
1843 switch (pai->ai_family) {
1844 case AF_UNSPEC:
1845 /* prefer IPv6 */
1846 q.name = name;
1847 q.qclass = C_IN;
1848 q.answer = buf->buf;
1849 q.anslen = sizeof(buf->buf);
1850 int query_ipv6 = 1, query_ipv4 = 1;
1851 if (pai->ai_flags & AI_ADDRCONFIG) {
1852 query_ipv6 = _have_ipv6();
1853 query_ipv4 = _have_ipv4();
1854 }
1855 if (query_ipv6) {
1856 q.qtype = T_AAAA;
1857 if (query_ipv4) {
1858 q.next = &q2;
1859 q2.name = name;
1860 q2.qclass = C_IN;
1861 q2.qtype = T_A;
1862 q2.answer = buf2->buf;
1863 q2.anslen = sizeof(buf2->buf);
1864 }
1865 } else if (query_ipv4) {
1866 q.qtype = T_A;
1867 } else {
1868 free(buf);
1869 free(buf2);
1870 return NS_NOTFOUND;
1871 }
1872 break;
1873 case AF_INET:
1874 q.name = name;
1875 q.qclass = C_IN;
1876 q.qtype = T_A;
1877 q.answer = buf->buf;
1878 q.anslen = sizeof(buf->buf);
1879 break;
1880 case AF_INET6:
1881 q.name = name;
1882 q.qclass = C_IN;
1883 q.qtype = T_AAAA;
1884 q.answer = buf->buf;
1885 q.anslen = sizeof(buf->buf);
1886 break;
1887 default:
1888 free(buf);
1889 free(buf2);
1890 return NS_UNAVAIL;
1891 }
1892
1893 res = __res_get_state();
1894 if (res == NULL) {
1895 free(buf);
1896 free(buf2);
1897 return NS_NOTFOUND;
1898 }
1899
1900 if (res_searchN(name, &q, res) < 0) {
1901 __res_put_state(res);
1902 free(buf);
1903 free(buf2);
1904 return NS_NOTFOUND;
1905 }
1906 ai = getanswer(buf, q.n, q.name, q.qtype, pai);
1907 if (ai) {
1908 cur->ai_next = ai;
1909 while (cur && cur->ai_next)
1910 cur = cur->ai_next;
1911 }
1912 if (q.next) {
1913 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai);
1914 if (ai)
1915 cur->ai_next = ai;
1916 }
1917 free(buf);
1918 free(buf2);
1919 if (sentinel.ai_next == NULL) {
1920 __res_put_state(res);
1921 switch (h_errno) {
1922 case HOST_NOT_FOUND:
1923 return NS_NOTFOUND;
1924 case TRY_AGAIN:
1925 return NS_TRYAGAIN;
1926 default:
1927 return NS_UNAVAIL;
1928 }
1929 }
1930
1931 _rfc3484_sort(&sentinel);
1932
1933 __res_put_state(res);
1934
1935 *((struct addrinfo **)rv) = sentinel.ai_next;
1936 return NS_SUCCESS;
1937 }
1938
1939 static void
1940 _sethtent(_pseudo_FILE * __restrict__ hostf)
1941 {
1942 assert(hostf);
1943 if (hostf->mapping == MAP_FAILED)
1944 (void) _pseudo_fopen_r(hostf, _PATH_HOSTS);
1945 else
1946 _pseudo_rewind(hostf);
1947 }
1948
1949 static void
1950 _endhtent(_pseudo_FILE * __restrict__ hostf)
1951 {
1952 assert(hostf);
1953 (void) _pseudo_fclose(hostf);
1954 }
1955
1956 static struct addrinfo *
1957 _gethtent(_pseudo_FILE * __restrict__ hostf, const char *name, const struct addrinfo *pai)
1958 {
1959 char *p;
1960 char *cp, *tname, *cname;
1961 struct addrinfo hints, *res0, *res;
1962 int error;
1963 const char *addr;
1964 char hostbuf[8*1024];
1965
1966 assert(hostf);
1967 // fprintf(stderr, "_gethtent() name = '%s'\n", name);
1968 assert(name != NULL);
1969 assert(pai != NULL);
1970
1971 if (hostf->mapping == MAP_FAILED)
1972 (void) _pseudo_fopen_r(hostf, _PATH_HOSTS);
1973 if (hostf->mapping == MAP_FAILED)
1974 return (NULL);
1975 again:
1976 if (!(p = _pseudo_fgets(hostbuf, sizeof hostbuf, hostf)))
1977 return (NULL);
1978 if (*p == '#')
1979 goto again;
1980 if (!(cp = strpbrk(p, "#\n")))
1981 goto again;
1982 *cp = '\0';
1983 if (!(cp = strpbrk(p, " \t")))
1984 goto again;
1985 *cp++ = '\0';
1986 addr = p;
1987 /* if this is not something we're looking for, skip it. */
1988 cname = NULL;
1989 while (cp && *cp) {
1990 if (*cp == ' ' || *cp == '\t') {
1991 cp++;
1992 continue;
1993 }
1994 if (!cname)
1995 cname = cp;
1996 tname = cp;
1997 if ((cp = strpbrk(cp, " \t")) != NULL)
1998 *cp++ = '\0';
1999 // fprintf(stderr, "\ttname = '%s'", tname);
2000 if (strcasecmp(name, tname) == 0)
2001 goto found;
2002 }
2003 goto again;
2004
2005 found:
2006 hints = *pai;
2007 hints.ai_flags = AI_NUMERICHOST;
2008 error = __wrap_getaddrinfo(addr, NULL, &hints, &res0);
2009 if (error)
2010 goto again;
2011 for (res = res0; res; res = res->ai_next) {
2012 /* cover it up */
2013 res->ai_flags = pai->ai_flags;
2014
2015 if (pai->ai_flags & AI_CANONNAME) {
2016 if (get_canonname(pai, res, cname) != 0) {
2017 __wrap_freeaddrinfo(res0);
2018 goto again;
2019 }
2020 }
2021 }
2022 return res0;
2023 }
2024
2025 /*ARGSUSED*/
2026 static int
2027 _files_getaddrinfo(void *rv, void *cb_data, va_list ap)
2028 {
2029 const char *name;
2030 const struct addrinfo *pai;
2031 struct addrinfo sentinel, *cur;
2032 struct addrinfo *p;
2033 _pseudo_FILE hostf = _PSEUDO_FILE_INITIALIZER;
2034
2035 name = va_arg(ap, char *);
2036 pai = va_arg(ap, struct addrinfo *);
2037
2038 // fprintf(stderr, "_files_getaddrinfo() name = '%s'\n", name);
2039 memset(&sentinel, 0, sizeof(sentinel));
2040 cur = &sentinel;
2041
2042 _sethtent(&hostf);
2043 while ((p = _gethtent(&hostf, name, pai)) != NULL) {
2044 cur->ai_next = p;
2045 while (cur && cur->ai_next)
2046 cur = cur->ai_next;
2047 }
2048 _endhtent(&hostf);
2049
2050 *((struct addrinfo **)rv) = sentinel.ai_next;
2051 if (sentinel.ai_next == NULL)
2052 return NS_NOTFOUND;
2053 return NS_SUCCESS;
2054 }
2055
2056 /* resolver logic */
2057
2058 /*
2059 * Formulate a normal query, send, and await answer.
2060 * Returned answer is placed in supplied buffer "answer".
2061 * Perform preliminary check of answer, returning success only
2062 * if no error is indicated and the answer count is nonzero.
2063 * Return the size of the response on success, -1 on error.
2064 * Error number is left in h_errno.
2065 *
2066 * Caller must parse answer and determine whether it answers the question.
2067 */
2068 static int
2069 res_queryN(const char *name, /* domain name */ struct res_target *target,
2070 res_state res)
2071 {
2072 u_char buf[MAXPACKET];
2073 HEADER *hp;
2074 int n;
2075 struct res_target *t;
2076 int rcode;
2077 int ancount;
2078
2079 assert(name != NULL);
2080 /* XXX: target may be NULL??? */
2081
2082 rcode = NOERROR;
2083 ancount = 0;
2084
2085 for (t = target; t; t = t->next) {
2086 int class, type;
2087 u_char *answer;
2088 int anslen;
2089
2090 hp = (HEADER *)(void *)t->answer;
2091 hp->rcode = NOERROR; /* default */
2092
2093 /* make it easier... */
2094 class = t->qclass;
2095 type = t->qtype;
2096 answer = t->answer;
2097 anslen = t->anslen;
2098 #ifdef DEBUG
2099 if (res->options & RES_DEBUG)
2100 printf(";; res_nquery(%s, %d, %d)\n", name, class, type);
2101 #endif
2102
2103 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
2104 buf, sizeof(buf));
2105 #ifdef RES_USE_EDNS0
2106 if (n > 0 && (res->options & RES_USE_EDNS0) != 0)
2107 n = res_nopt(res, n, buf, sizeof(buf), anslen);
2108 #endif
2109 if (n <= 0) {
2110 #ifdef DEBUG
2111 if (res->options & RES_DEBUG)
2112 printf(";; res_nquery: mkquery failed\n");
2113 #endif
2114 h_errno = NO_RECOVERY;
2115 return n;
2116 }
2117 n = res_nsend(res, buf, n, answer, anslen);
2118 #if 0
2119 if (n < 0) {
2120 #ifdef DEBUG
2121 if (res->options & RES_DEBUG)
2122 printf(";; res_query: send error\n");
2123 #endif
2124 h_errno = TRY_AGAIN;
2125 return n;
2126 }
2127 #endif
2128
2129 if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
2130 rcode = hp->rcode; /* record most recent error */
2131 #ifdef DEBUG
2132 if (res->options & RES_DEBUG)
2133 printf(";; rcode = %u, ancount=%u\n", hp->rcode,
2134 ntohs(hp->ancount));
2135 #endif
2136 continue;
2137 }
2138
2139 ancount += ntohs(hp->ancount);
2140
2141 t->n = n;
2142 }
2143
2144 if (ancount == 0) {
2145 switch (rcode) {
2146 case NXDOMAIN:
2147 h_errno = HOST_NOT_FOUND;
2148 break;
2149 case SERVFAIL:
2150 h_errno = TRY_AGAIN;
2151 break;
2152 case NOERROR:
2153 h_errno = NO_DATA;
2154 break;
2155 case FORMERR:
2156 case NOTIMP:
2157 case REFUSED:
2158 default:
2159 h_errno = NO_RECOVERY;
2160 break;
2161 }
2162 return -1;
2163 }
2164 return ancount;
2165 }
2166
2167 /*
2168 * Formulate a normal query, send, and retrieve answer in supplied buffer.
2169 * Return the size of the response on success, -1 on error.
2170 * If enabled, implement search rules until answer or unrecoverable failure
2171 * is detected. Error code, if any, is left in h_errno.
2172 */
2173 static int
2174 res_searchN(const char *name, struct res_target *target, res_state res)
2175 {
2176 const char *cp, * const *domain;
2177 HEADER *hp;
2178 u_int dots;
2179 int trailing_dot, ret, saved_herrno;
2180 int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
2181
2182 assert(name != NULL);
2183 assert(target != NULL);
2184
2185 hp = (HEADER *)(void *)target->answer; /*XXX*/
2186
2187 errno = 0;
2188 h_errno = HOST_NOT_FOUND; /* default, if we never query */
2189 dots = 0;
2190 for (cp = name; *cp; cp++)
2191 dots += (*cp == '.');
2192 trailing_dot = 0;
2193 if (cp > name && *--cp == '.')
2194 trailing_dot++;
2195
2196
2197 //fprintf(stderr, "res_searchN() name = '%s'\n", name);
2198
2199 /*
2200 * if there aren't any dots, it could be a user-level alias
2201 */
2202 if (!dots && (cp = __hostalias(name)) != NULL) {
2203 ret = res_queryN(cp, target, res);
2204 return ret;
2205 }
2206
2207 /*
2208 * If there are dots in the name already, let's just give it a try
2209 * 'as is'. The threshold can be set with the "ndots" option.
2210 */
2211 saved_herrno = -1;
2212 if (dots >= res->ndots) {
2213 ret = res_querydomainN(name, NULL, target, res);
2214 if (ret > 0)
2215 return (ret);
2216 saved_herrno = h_errno;
2217 tried_as_is++;
2218 }
2219
2220 /*
2221 * We do at least one level of search if
2222 * - there is no dot and RES_DEFNAME is set, or
2223 * - there is at least one dot, there is no trailing dot,
2224 * and RES_DNSRCH is set.
2225 */
2226 if ((!dots && (res->options & RES_DEFNAMES)) ||
2227 (dots && !trailing_dot && (res->options & RES_DNSRCH))) {
2228 int done = 0;
2229
2230 for (domain = (const char * const *)res->dnsrch;
2231 *domain && !done;
2232 domain++) {
2233
2234 ret = res_querydomainN(name, *domain, target, res);
2235 if (ret > 0)
2236 return ret;
2237
2238 /*
2239 * If no server present, give up.
2240 * If name isn't found in this domain,
2241 * keep trying higher domains in the search list
2242 * (if that's enabled).
2243 * On a NO_DATA error, keep trying, otherwise
2244 * a wildcard entry of another type could keep us
2245 * from finding this entry higher in the domain.
2246 * If we get some other error (negative answer or
2247 * server failure), then stop searching up,
2248 * but try the input name below in case it's
2249 * fully-qualified.
2250 */
2251 if (errno == ECONNREFUSED) {
2252 h_errno = TRY_AGAIN;
2253 return -1;
2254 }
2255
2256 switch (h_errno) {
2257 case NO_DATA:
2258 got_nodata++;
2259 /* FALLTHROUGH */
2260 case HOST_NOT_FOUND:
2261 /* keep trying */
2262 break;
2263 case TRY_AGAIN:
2264 if (hp->rcode == SERVFAIL) {
2265 /* try next search element, if any */
2266 got_servfail++;
2267 break;
2268 }
2269 /* FALLTHROUGH */
2270 default:
2271 /* anything else implies that we're done */
2272 done++;
2273 }
2274 /*
2275 * if we got here for some reason other than DNSRCH,
2276 * we only wanted one iteration of the loop, so stop.
2277 */
2278 if (!(res->options & RES_DNSRCH))
2279 done++;
2280 }
2281 }
2282
2283 /*
2284 * if we have not already tried the name "as is", do that now.
2285 * note that we do this regardless of how many dots were in the
2286 * name or whether it ends with a dot.
2287 */
2288 if (!tried_as_is) {
2289 ret = res_querydomainN(name, NULL, target, res);
2290 if (ret > 0)
2291 return ret;
2292 }
2293
2294 /*
2295 * if we got here, we didn't satisfy the search.
2296 * if we did an initial full query, return that query's h_errno
2297 * (note that we wouldn't be here if that query had succeeded).
2298 * else if we ever got a nodata, send that back as the reason.
2299 * else send back meaningless h_errno, that being the one from
2300 * the last DNSRCH we did.
2301 */
2302 if (saved_herrno != -1)
2303 h_errno = saved_herrno;
2304 else if (got_nodata)
2305 h_errno = NO_DATA;
2306 else if (got_servfail)
2307 h_errno = TRY_AGAIN;
2308 return -1;
2309 }
2310
2311 /*
2312 * Perform a call on res_query on the concatenation of name and domain,
2313 * removing a trailing dot from name if domain is NULL.
2314 */
2315 static int
2316 res_querydomainN(const char *name, const char *domain,
2317 struct res_target *target, res_state res)
2318 {
2319 char nbuf[MAXDNAME];
2320 const char *longname = nbuf;
2321 size_t n, d;
2322
2323 assert(name != NULL);
2324 /* XXX: target may be NULL??? */
2325
2326 #ifdef DEBUG
2327 if (res->options & RES_DEBUG)
2328 printf(";; res_querydomain(%s, %s)\n",
2329 name, domain?domain:"<Nil>");
2330 #endif
2331 if (domain == NULL) {
2332 /*
2333 * Check for trailing '.';
2334 * copy without '.' if present.
2335 */
2336 n = strlen(name);
2337 if (n + 1 > sizeof(nbuf)) {
2338 h_errno = NO_RECOVERY;
2339 return -1;
2340 }
2341 if (n > 0 && name[--n] == '.') {
2342 strncpy(nbuf, name, n);
2343 nbuf[n] = '\0';
2344 } else
2345 longname = name;
2346 } else {
2347 n = strlen(name);
2348 d = strlen(domain);
2349 if (n + 1 + d + 1 > sizeof(nbuf)) {
2350 h_errno = NO_RECOVERY;
2351 return -1;
2352 }
2353 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
2354 }
2355 return res_queryN(longname, target, res);
2356 }

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