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 * Issues to be discussed:
35 * - Thread safe-ness must be checked.
36 * - Return values. There are nonstandard return values defined and used
37 * in the source code. This is because RFC2553 is silent about which error
38 * code must be returned for which situation.
39 * - IPv4 classful (shortened) form. RFC2553 is silent about it. XNET 5.2
40 * says to use inet_aton() to convert IPv4 numeric to binary (alows
41 * classful form as a result).
42 * current code - disallow classful form for IPv4 (due to use of inet_pton).
43 * - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is
44 * invalid.
45 * current code - SEGV on freeaddrinfo(NULL)
46 * Note:
47 * - We use getipnodebyname() just for thread-safeness. There's no intent
48 * to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to
49 * getipnodebyname().
50 * - The code filters out AFs that are not supported by the kernel,
51 * when globbing NULL hostname (to loopback, or wildcard). Is it the right
52 * thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG
53 * in ai_flags?
54 * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.
55 * (1) what should we do against numeric hostname (2) what should we do
56 * against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready?
57 * non-loopback address configured? global address configured?
58 * - To avoid search order issue, we have a big amount of code duplicate
59 * from gethnamaddr.c and some other places. The issues that there's no
60 * lower layer function to lookup "IPv4 or IPv6" record. Calling
61 * gethostbyname2 from getaddrinfo will end up in wrong search order, as
62 * follows:
63 * - The code makes use of following calls when asked to resolver with
64 * ai_family = PF_UNSPEC:
65 * getipnodebyname(host, AF_INET6);
66 * getipnodebyname(host, AF_INET);
67 * This will result in the following queries if the node is configure to
68 * prefer /etc/hosts than DNS:
69 * lookup /etc/hosts for IPv6 address
70 * lookup DNS for IPv6 address
71 * lookup /etc/hosts for IPv4 address
72 * lookup DNS for IPv4 address
73 * which may not meet people's requirement.
74 * The right thing to happen is to have underlying layer which does
75 * PF_UNSPEC lookup (lookup both) and return chain of addrinfos.
76 * This would result in a bit of code duplicate with _dns_ghbyname() and
77 * friends.
78 */
79
80 #include <fcntl.h>
81 #include <sys/cdefs.h>
82 #include <sys/types.h>
83 #include <sys/stat.h>
84 #include <sys/param.h>
85 #include <sys/socket.h>
86 #include <sys/un.h>
87 #include <net/if.h>
88 #include <netinet/in.h>
89 #include <arpa/inet.h>
90 #include <arpa/nameser.h>
91 #include <assert.h>
92 #include <ctype.h>
93 #include <errno.h>
94 #include <netdb.h>
95 #include "NetdClientDispatch.h"
96 #include "resolv_cache.h"
97 #include "resolv_netid.h"
98 #include "resolv_private.h"
99 #include <stdbool.h>
100 #include <stddef.h>
101 #include <stdio.h>
102 #include <stdlib.h>
103 #include <string.h>
104 #include <strings.h>
105 #include <unistd.h>
106
107 #include <syslog.h>
108 #include <stdarg.h>
109 #include "nsswitch.h"
110
111 #ifdef ANDROID_CHANGES
112 #include <sys/system_properties.h>
113 #endif /* ANDROID_CHANGES */
114
115 typedef union sockaddr_union {
116 struct sockaddr generic;
117 struct sockaddr_in in;
118 struct sockaddr_in6 in6;
119 } sockaddr_union;
120
121 #define SUCCESS 0
122 #define ANY 0
123 #define YES 1
124 #define NO 0
125
126 static const char in_addrany[] = { 0, 0, 0, 0 };
127 static const char in_loopback[] = { 127, 0, 0, 1 };
128 #ifdef INET6
129 static const char in6_addrany[] = {
130 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
131 };
132 static const char in6_loopback[] = {
133 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
134 };
135 #endif
136
137 // This should be synchronized to ResponseCode.h
138 static const int DnsProxyQueryResult = 222;
139
140 static const struct afd {
141 int a_af;
142 int a_addrlen;
143 int a_socklen;
144 int a_off;
145 const char *a_addrany;
146 const char *a_loopback;
147 int a_scoped;
148 } afdl [] = {
149 #ifdef INET6
150 {PF_INET6, sizeof(struct in6_addr),
151 sizeof(struct sockaddr_in6),
152 offsetof(struct sockaddr_in6, sin6_addr),
153 in6_addrany, in6_loopback, 1},
154 #endif
155 {PF_INET, sizeof(struct in_addr),
156 sizeof(struct sockaddr_in),
157 offsetof(struct sockaddr_in, sin_addr),
158 in_addrany, in_loopback, 0},
159 {0, 0, 0, 0, NULL, NULL, 0},
160 };
161
162 struct explore {
163 int e_af;
164 int e_socktype;
165 int e_protocol;
166 const char *e_protostr;
167 int e_wild;
168 #define WILD_AF(ex) ((ex)->e_wild & 0x01)
169 #define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02)
170 #define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04)
171 };
172
173 static const struct explore explore[] = {
174 #if 0
175 { PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
176 #endif
177 #ifdef INET6
178 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
179 { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
180 { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 },
181 #endif
182 { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
183 { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
184 { PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
185 { PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
186 { PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
187 { PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 },
188 { -1, 0, 0, NULL, 0 },
189 };
190
191 #ifdef INET6
192 #define PTON_MAX 16
193 #else
194 #define PTON_MAX 4
195 #endif
196
197 static const ns_src default_dns_files[] = {
198 { NSSRC_FILES, NS_SUCCESS },
199 { NSSRC_DNS, NS_SUCCESS },
200 { 0, 0 }
201 };
202
203 #define MAXPACKET (64*1024)
204
205 typedef union {
206 HEADER hdr;
207 u_char buf[MAXPACKET];
208 } querybuf;
209
210 struct res_target {
211 struct res_target *next;
212 const char *name; /* domain name */
213 int qclass, qtype; /* class and type of query */
214 u_char *answer; /* buffer to put answer */
215 int anslen; /* size of answer buffer */
216 int n; /* result length */
217 };
218
219 static int str2number(const char *);
220 static int explore_fqdn(const struct addrinfo *, const char *,
221 const char *, struct addrinfo **, unsigned netid, unsigned mark);
222 static int explore_null(const struct addrinfo *,
223 const char *, struct addrinfo **);
224 static int explore_numeric(const struct addrinfo *, const char *,
225 const char *, struct addrinfo **, const char *);
226 static int explore_numeric_scope(const struct addrinfo *, const char *,
227 const char *, struct addrinfo **);
228 static int get_canonname(const struct addrinfo *,
229 struct addrinfo *, const char *);
230 static struct addrinfo *get_ai(const struct addrinfo *,
231 const struct afd *, const char *);
232 static int get_portmatch(const struct addrinfo *, const char *);
233 static int get_port(const struct addrinfo *, const char *, int);
234 static const struct afd *find_afd(int);
235 #ifdef INET6
236 static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *);
237 #endif
238
239 static struct addrinfo *getanswer(const querybuf *, int, const char *, int,
240 const struct addrinfo *);
241 static int _dns_getaddrinfo(void *, void *, va_list);
242 static void _sethtent(FILE **);
243 static void _endhtent(FILE **);
244 static struct addrinfo *_gethtent(FILE **, const char *,
245 const struct addrinfo *);
246 static int _files_getaddrinfo(void *, void *, va_list);
247
248 static int res_queryN(const char *, struct res_target *, res_state);
249 static int res_searchN(const char *, struct res_target *, res_state);
250 static int res_querydomainN(const char *, const char *,
251 struct res_target *, res_state);
252
253 static const char * const ai_errlist[] = {
254 "Success",
255 "Address family for hostname not supported", /* EAI_ADDRFAMILY */
256 "Temporary failure in name resolution", /* EAI_AGAIN */
257 "Invalid value for ai_flags", /* EAI_BADFLAGS */
258 "Non-recoverable failure in name resolution", /* EAI_FAIL */
259 "ai_family not supported", /* EAI_FAMILY */
260 "Memory allocation failure", /* EAI_MEMORY */
261 "No address associated with hostname", /* EAI_NODATA */
262 "hostname nor servname provided, or not known", /* EAI_NONAME */
263 "servname not supported for ai_socktype", /* EAI_SERVICE */
264 "ai_socktype not supported", /* EAI_SOCKTYPE */
265 "System error returned in errno", /* EAI_SYSTEM */
266 "Invalid value for hints", /* EAI_BADHINTS */
267 "Resolved protocol is unknown", /* EAI_PROTOCOL */
268 "Argument buffer overflow", /* EAI_OVERFLOW */
269 "Unknown error", /* EAI_MAX */
270 };
271
272 /* XXX macros that make external reference is BAD. */
273
274 #define GET_AI(ai, afd, addr) \
275 do { \
276 /* external reference: pai, error, and label free */ \
277 (ai) = get_ai(pai, (afd), (addr)); \
278 if ((ai) == NULL) { \
279 error = EAI_MEMORY; \
280 goto free; \
281 } \
282 } while (/*CONSTCOND*/0)
283
284 #define GET_PORT(ai, serv) \
285 do { \
286 /* external reference: error and label free */ \
287 error = get_port((ai), (serv), 0); \
288 if (error != 0) \
289 goto free; \
290 } while (/*CONSTCOND*/0)
291
292 #define GET_CANONNAME(ai, str) \
293 do { \
294 /* external reference: pai, error and label free */ \
295 error = get_canonname(pai, (ai), (str)); \
296 if (error != 0) \
297 goto free; \
298 } while (/*CONSTCOND*/0)
299
300 #define ERR(err) \
301 do { \
302 /* external reference: error, and label bad */ \
303 error = (err); \
304 goto bad; \
305 /*NOTREACHED*/ \
306 } while (/*CONSTCOND*/0)
307
308 #define MATCH_FAMILY(x, y, w) \
309 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || \
310 (y) == PF_UNSPEC)))
311 #define MATCH(x, y, w) \
312 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
313
314 const char *
gai_strerror(int ecode)315 gai_strerror(int ecode)
316 {
317 if (ecode < 0 || ecode > EAI_MAX)
318 ecode = EAI_MAX;
319 return ai_errlist[ecode];
320 }
321
322 void
freeaddrinfo(struct addrinfo * ai)323 freeaddrinfo(struct addrinfo *ai)
324 {
325 struct addrinfo *next;
326
327 assert(ai != NULL);
328
329 do {
330 next = ai->ai_next;
331 if (ai->ai_canonname)
332 free(ai->ai_canonname);
333 /* no need to free(ai->ai_addr) */
334 free(ai);
335 ai = next;
336 } while (ai);
337 }
338
339 static int
str2number(const char * p)340 str2number(const char *p)
341 {
342 char *ep;
343 unsigned long v;
344
345 assert(p != NULL);
346
347 if (*p == '\0')
348 return -1;
349 ep = NULL;
350 errno = 0;
351 v = strtoul(p, &ep, 10);
352 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX)
353 return v;
354 else
355 return -1;
356 }
357
358 /*
359 * Connect a UDP socket to a given unicast address. This will cause no network
360 * traffic, but will fail fast if the system has no or limited reachability to
361 * the destination (e.g., no IPv4 address, no IPv6 default route, ...).
362 */
363 static int
_test_connect(int pf,struct sockaddr * addr,size_t addrlen,unsigned mark)364 _test_connect(int pf, struct sockaddr *addr, size_t addrlen, unsigned mark) {
365 int s = socket(pf, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
366 if (s < 0)
367 return 0;
368 if (mark != MARK_UNSET && setsockopt(s, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0)
369 return 0;
370 int ret;
371 do {
372 ret = __connect(s, addr, addrlen);
373 } while (ret < 0 && errno == EINTR);
374 int success = (ret == 0);
375 do {
376 ret = close(s);
377 } while (ret < 0 && errno == EINTR);
378 return success;
379 }
380
381 /*
382 * The following functions determine whether IPv4 or IPv6 connectivity is
383 * available in order to implement AI_ADDRCONFIG.
384 *
385 * Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is
386 * available, but whether addresses of the specified family are "configured
387 * on the local system". However, bionic doesn't currently support getifaddrs,
388 * so checking for connectivity is the next best thing.
389 */
390 static int
_have_ipv6(unsigned mark)391 _have_ipv6(unsigned mark) {
392 static const struct sockaddr_in6 sin6_test = {
393 .sin6_family = AF_INET6,
394 .sin6_addr.s6_addr = { // 2000::
395 0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
396 };
397 sockaddr_union addr = { .in6 = sin6_test };
398 return _test_connect(PF_INET6, &addr.generic, sizeof(addr.in6), mark);
399 }
400
401 static int
_have_ipv4(unsigned mark)402 _have_ipv4(unsigned mark) {
403 static const struct sockaddr_in sin_test = {
404 .sin_family = AF_INET,
405 .sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8
406 };
407 sockaddr_union addr = { .in = sin_test };
408 return _test_connect(PF_INET, &addr.generic, sizeof(addr.in), mark);
409 }
410
411 // Returns 0 on success, else returns on error.
412 static int
android_getaddrinfo_proxy(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res,unsigned netid)413 android_getaddrinfo_proxy(
414 const char *hostname, const char *servname,
415 const struct addrinfo *hints, struct addrinfo **res, unsigned netid)
416 {
417 int sock;
418 const int one = 1;
419 struct sockaddr_un proxy_addr;
420 FILE* proxy = NULL;
421 int success = 0;
422
423 // Clear this at start, as we use its non-NULLness later (in the
424 // error path) to decide if we have to free up any memory we
425 // allocated in the process (before failing).
426 *res = NULL;
427
428 // Bogus things we can't serialize. Don't use the proxy. These will fail - let them.
429 if ((hostname != NULL &&
430 strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) ||
431 (servname != NULL &&
432 strcspn(servname, " \n\r\t^'\"") != strlen(servname))) {
433 return EAI_NODATA;
434 }
435
436 sock = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
437 if (sock < 0) {
438 return EAI_NODATA;
439 }
440
441 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
442 memset(&proxy_addr, 0, sizeof(proxy_addr));
443 proxy_addr.sun_family = AF_UNIX;
444 strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd",
445 sizeof(proxy_addr.sun_path));
446 if (TEMP_FAILURE_RETRY(connect(sock,
447 (const struct sockaddr*) &proxy_addr,
448 sizeof(proxy_addr))) != 0) {
449 close(sock);
450 return EAI_NODATA;
451 }
452
453 netid = __netdClientDispatch.netIdForResolv(netid);
454
455 // Send the request.
456 proxy = fdopen(sock, "r+");
457 if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d %u",
458 hostname == NULL ? "^" : hostname,
459 servname == NULL ? "^" : servname,
460 hints == NULL ? -1 : hints->ai_flags,
461 hints == NULL ? -1 : hints->ai_family,
462 hints == NULL ? -1 : hints->ai_socktype,
463 hints == NULL ? -1 : hints->ai_protocol,
464 netid) < 0) {
465 goto exit;
466 }
467 // literal NULL byte at end, required by FrameworkListener
468 if (fputc(0, proxy) == EOF ||
469 fflush(proxy) != 0) {
470 goto exit;
471 }
472
473 char buf[4];
474 // read result code for gethostbyaddr
475 if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) {
476 goto exit;
477 }
478
479 int result_code = (int)strtol(buf, NULL, 10);
480 // verify the code itself
481 if (result_code != DnsProxyQueryResult ) {
482 fread(buf, 1, sizeof(buf), proxy);
483 goto exit;
484 }
485
486 struct addrinfo* ai = NULL;
487 struct addrinfo** nextres = res;
488 while (1) {
489 uint32_t addrinfo_len;
490 if (fread(&addrinfo_len, sizeof(addrinfo_len),
491 1, proxy) != 1) {
492 break;
493 }
494 addrinfo_len = ntohl(addrinfo_len);
495 if (addrinfo_len == 0) {
496 success = 1;
497 break;
498 }
499
500 if (addrinfo_len < sizeof(struct addrinfo)) {
501 break;
502 }
503 struct addrinfo* ai = calloc(1, addrinfo_len +
504 sizeof(struct sockaddr_storage));
505 if (ai == NULL) {
506 break;
507 }
508
509 if (fread(ai, addrinfo_len, 1, proxy) != 1) {
510 // Error; fall through.
511 break;
512 }
513
514 // Zero out the pointer fields we copied which aren't
515 // valid in this address space.
516 ai->ai_addr = NULL;
517 ai->ai_canonname = NULL;
518 ai->ai_next = NULL;
519
520 // struct sockaddr
521 uint32_t addr_len;
522 if (fread(&addr_len, sizeof(addr_len), 1, proxy) != 1) {
523 break;
524 }
525 addr_len = ntohl(addr_len);
526 if (addr_len != 0) {
527 if (addr_len > sizeof(struct sockaddr_storage)) {
528 // Bogus; too big.
529 break;
530 }
531 struct sockaddr* addr = (struct sockaddr*)(ai + 1);
532 if (fread(addr, addr_len, 1, proxy) != 1) {
533 break;
534 }
535 ai->ai_addr = addr;
536 }
537
538 // cannonname
539 uint32_t name_len;
540 if (fread(&name_len, sizeof(name_len), 1, proxy) != 1) {
541 break;
542 }
543 name_len = ntohl(name_len);
544 if (name_len != 0) {
545 ai->ai_canonname = (char*) malloc(name_len);
546 if (fread(ai->ai_canonname, name_len, 1, proxy) != 1) {
547 break;
548 }
549 if (ai->ai_canonname[name_len - 1] != '\0') {
550 // The proxy should be returning this
551 // NULL-terminated.
552 break;
553 }
554 }
555
556 *nextres = ai;
557 nextres = &ai->ai_next;
558 ai = NULL;
559 }
560
561 if (ai != NULL) {
562 // Clean up partially-built addrinfo that we never ended up
563 // attaching to the response.
564 freeaddrinfo(ai);
565 }
566 exit:
567 if (proxy != NULL) {
568 fclose(proxy);
569 }
570
571 if (success) {
572 return 0;
573 }
574
575 // Proxy failed;
576 // clean up memory we might've allocated.
577 if (*res) {
578 freeaddrinfo(*res);
579 *res = NULL;
580 }
581 return EAI_NODATA;
582 }
583
584 int
getaddrinfo(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res)585 getaddrinfo(const char *hostname, const char *servname,
586 const struct addrinfo *hints, struct addrinfo **res)
587 {
588 return android_getaddrinfofornet(hostname, servname, hints, NETID_UNSET, MARK_UNSET, res);
589 }
590
591 int
android_getaddrinfofornet(const char * hostname,const char * servname,const struct addrinfo * hints,unsigned netid,unsigned mark,struct addrinfo ** res)592 android_getaddrinfofornet(const char *hostname, const char *servname,
593 const struct addrinfo *hints, unsigned netid, unsigned mark, struct addrinfo **res)
594 {
595 struct addrinfo sentinel;
596 struct addrinfo *cur;
597 int error = 0;
598 struct addrinfo ai;
599 struct addrinfo ai0;
600 struct addrinfo *pai;
601 const struct explore *ex;
602 const char* cache_mode = getenv("ANDROID_DNS_MODE");
603
604 /* hostname is allowed to be NULL */
605 /* servname is allowed to be NULL */
606 /* hints is allowed to be NULL */
607 assert(res != NULL);
608 memset(&sentinel, 0, sizeof(sentinel));
609 cur = &sentinel;
610 pai = &ai;
611 pai->ai_flags = 0;
612 pai->ai_family = PF_UNSPEC;
613 pai->ai_socktype = ANY;
614 pai->ai_protocol = ANY;
615 pai->ai_addrlen = 0;
616 pai->ai_canonname = NULL;
617 pai->ai_addr = NULL;
618 pai->ai_next = NULL;
619
620 if (hostname == NULL && servname == NULL)
621 return EAI_NONAME;
622 if (hints) {
623 /* error check for hints */
624 if (hints->ai_addrlen || hints->ai_canonname ||
625 hints->ai_addr || hints->ai_next)
626 ERR(EAI_BADHINTS); /* xxx */
627 if (hints->ai_flags & ~AI_MASK)
628 ERR(EAI_BADFLAGS);
629 switch (hints->ai_family) {
630 case PF_UNSPEC:
631 case PF_INET:
632 #ifdef INET6
633 case PF_INET6:
634 #endif
635 break;
636 default:
637 ERR(EAI_FAMILY);
638 }
639 memcpy(pai, hints, sizeof(*pai));
640
641 /*
642 * if both socktype/protocol are specified, check if they
643 * are meaningful combination.
644 */
645 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
646 for (ex = explore; ex->e_af >= 0; ex++) {
647 if (pai->ai_family != ex->e_af)
648 continue;
649 if (ex->e_socktype == ANY)
650 continue;
651 if (ex->e_protocol == ANY)
652 continue;
653 if (pai->ai_socktype == ex->e_socktype
654 && pai->ai_protocol != ex->e_protocol) {
655 ERR(EAI_BADHINTS);
656 }
657 }
658 }
659 }
660
661 /*
662 * check for special cases. (1) numeric servname is disallowed if
663 * socktype/protocol are left unspecified. (2) servname is disallowed
664 * for raw and other inet{,6} sockets.
665 */
666 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
667 #ifdef PF_INET6
668 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
669 #endif
670 ) {
671 ai0 = *pai; /* backup *pai */
672
673 if (pai->ai_family == PF_UNSPEC) {
674 #ifdef PF_INET6
675 pai->ai_family = PF_INET6;
676 #else
677 pai->ai_family = PF_INET;
678 #endif
679 }
680 error = get_portmatch(pai, servname);
681 if (error)
682 ERR(error);
683
684 *pai = ai0;
685 }
686
687 ai0 = *pai;
688
689 /* NULL hostname, or numeric hostname */
690 for (ex = explore; ex->e_af >= 0; ex++) {
691 *pai = ai0;
692
693 /* PF_UNSPEC entries are prepared for DNS queries only */
694 if (ex->e_af == PF_UNSPEC)
695 continue;
696
697 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
698 continue;
699 if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
700 continue;
701 if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
702 continue;
703
704 if (pai->ai_family == PF_UNSPEC)
705 pai->ai_family = ex->e_af;
706 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
707 pai->ai_socktype = ex->e_socktype;
708 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
709 pai->ai_protocol = ex->e_protocol;
710
711 if (hostname == NULL)
712 error = explore_null(pai, servname, &cur->ai_next);
713 else
714 error = explore_numeric_scope(pai, hostname, servname,
715 &cur->ai_next);
716
717 if (error)
718 goto free;
719
720 while (cur->ai_next)
721 cur = cur->ai_next;
722 }
723
724 /*
725 * XXX
726 * If numeric representation of AF1 can be interpreted as FQDN
727 * representation of AF2, we need to think again about the code below.
728 */
729 if (sentinel.ai_next)
730 goto good;
731
732 if (hostname == NULL)
733 ERR(EAI_NODATA);
734 if (pai->ai_flags & AI_NUMERICHOST)
735 ERR(EAI_NONAME);
736
737 /*
738 * BEGIN ANDROID CHANGES; proxying to the cache
739 */
740 if (cache_mode == NULL || strcmp(cache_mode, "local") != 0) {
741 // we're not the proxy - pass the request to them
742 return android_getaddrinfo_proxy(hostname, servname, hints, res, netid);
743 }
744
745 /*
746 * hostname as alphabetical name.
747 * we would like to prefer AF_INET6 than AF_INET, so we'll make a
748 * outer loop by AFs.
749 */
750 for (ex = explore; ex->e_af >= 0; ex++) {
751 *pai = ai0;
752
753 /* require exact match for family field */
754 if (pai->ai_family != ex->e_af)
755 continue;
756
757 if (!MATCH(pai->ai_socktype, ex->e_socktype,
758 WILD_SOCKTYPE(ex))) {
759 continue;
760 }
761 if (!MATCH(pai->ai_protocol, ex->e_protocol,
762 WILD_PROTOCOL(ex))) {
763 continue;
764 }
765
766 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
767 pai->ai_socktype = ex->e_socktype;
768 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
769 pai->ai_protocol = ex->e_protocol;
770
771 error = explore_fqdn(pai, hostname, servname,
772 &cur->ai_next, netid, mark);
773
774 while (cur && cur->ai_next)
775 cur = cur->ai_next;
776 }
777
778 /* XXX */
779 if (sentinel.ai_next)
780 error = 0;
781
782 if (error)
783 goto free;
784 if (error == 0) {
785 if (sentinel.ai_next) {
786 good:
787 *res = sentinel.ai_next;
788 return SUCCESS;
789 } else
790 error = EAI_FAIL;
791 }
792 free:
793 bad:
794 if (sentinel.ai_next)
795 freeaddrinfo(sentinel.ai_next);
796 *res = NULL;
797 return error;
798 }
799
800 /*
801 * FQDN hostname, DNS lookup
802 */
803 static int
explore_fqdn(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,unsigned netid,unsigned mark)804 explore_fqdn(const struct addrinfo *pai, const char *hostname,
805 const char *servname, struct addrinfo **res, unsigned netid, unsigned mark)
806 {
807 struct addrinfo *result;
808 struct addrinfo *cur;
809 int error = 0;
810 static const ns_dtab dtab[] = {
811 NS_FILES_CB(_files_getaddrinfo, NULL)
812 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
813 NS_NIS_CB(_yp_getaddrinfo, NULL)
814 { 0, 0, 0 }
815 };
816
817 assert(pai != NULL);
818 /* hostname may be NULL */
819 /* servname may be NULL */
820 assert(res != NULL);
821
822 result = NULL;
823
824 /*
825 * if the servname does not match socktype/protocol, ignore it.
826 */
827 if (get_portmatch(pai, servname) != 0)
828 return 0;
829
830 switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
831 default_dns_files, hostname, pai, netid, mark)) {
832 case NS_TRYAGAIN:
833 error = EAI_AGAIN;
834 goto free;
835 case NS_UNAVAIL:
836 error = EAI_FAIL;
837 goto free;
838 case NS_NOTFOUND:
839 error = EAI_NODATA;
840 goto free;
841 case NS_SUCCESS:
842 error = 0;
843 for (cur = result; cur; cur = cur->ai_next) {
844 GET_PORT(cur, servname);
845 /* canonname should be filled already */
846 }
847 break;
848 }
849
850 *res = result;
851
852 return 0;
853
854 free:
855 if (result)
856 freeaddrinfo(result);
857 return error;
858 }
859
860 /*
861 * hostname == NULL.
862 * passive socket -> anyaddr (0.0.0.0 or ::)
863 * non-passive socket -> localhost (127.0.0.1 or ::1)
864 */
865 static int
explore_null(const struct addrinfo * pai,const char * servname,struct addrinfo ** res)866 explore_null(const struct addrinfo *pai, const char *servname,
867 struct addrinfo **res)
868 {
869 int s;
870 const struct afd *afd;
871 struct addrinfo *cur;
872 struct addrinfo sentinel;
873 int error;
874
875 assert(pai != NULL);
876 /* servname may be NULL */
877 assert(res != NULL);
878
879 *res = NULL;
880 sentinel.ai_next = NULL;
881 cur = &sentinel;
882
883 /*
884 * filter out AFs that are not supported by the kernel
885 * XXX errno?
886 */
887 s = socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
888 if (s < 0) {
889 if (errno != EMFILE)
890 return 0;
891 } else
892 close(s);
893
894 /*
895 * if the servname does not match socktype/protocol, ignore it.
896 */
897 if (get_portmatch(pai, servname) != 0)
898 return 0;
899
900 afd = find_afd(pai->ai_family);
901 if (afd == NULL)
902 return 0;
903
904 if (pai->ai_flags & AI_PASSIVE) {
905 GET_AI(cur->ai_next, afd, afd->a_addrany);
906 /* xxx meaningless?
907 * GET_CANONNAME(cur->ai_next, "anyaddr");
908 */
909 GET_PORT(cur->ai_next, servname);
910 } else {
911 GET_AI(cur->ai_next, afd, afd->a_loopback);
912 /* xxx meaningless?
913 * GET_CANONNAME(cur->ai_next, "localhost");
914 */
915 GET_PORT(cur->ai_next, servname);
916 }
917 cur = cur->ai_next;
918
919 *res = sentinel.ai_next;
920 return 0;
921
922 free:
923 if (sentinel.ai_next)
924 freeaddrinfo(sentinel.ai_next);
925 return error;
926 }
927
928 /*
929 * numeric hostname
930 */
931 static int
explore_numeric(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,const char * canonname)932 explore_numeric(const struct addrinfo *pai, const char *hostname,
933 const char *servname, struct addrinfo **res, const char *canonname)
934 {
935 const struct afd *afd;
936 struct addrinfo *cur;
937 struct addrinfo sentinel;
938 int error;
939 char pton[PTON_MAX];
940
941 assert(pai != NULL);
942 /* hostname may be NULL */
943 /* servname may be NULL */
944 assert(res != NULL);
945
946 *res = NULL;
947 sentinel.ai_next = NULL;
948 cur = &sentinel;
949
950 /*
951 * if the servname does not match socktype/protocol, ignore it.
952 */
953 if (get_portmatch(pai, servname) != 0)
954 return 0;
955
956 afd = find_afd(pai->ai_family);
957 if (afd == NULL)
958 return 0;
959
960 switch (afd->a_af) {
961 #if 0 /*X/Open spec*/
962 case AF_INET:
963 if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
964 if (pai->ai_family == afd->a_af ||
965 pai->ai_family == PF_UNSPEC /*?*/) {
966 GET_AI(cur->ai_next, afd, pton);
967 GET_PORT(cur->ai_next, servname);
968 if ((pai->ai_flags & AI_CANONNAME)) {
969 /*
970 * Set the numeric address itself as
971 * the canonical name, based on a
972 * clarification in rfc2553bis-03.
973 */
974 GET_CANONNAME(cur->ai_next, canonname);
975 }
976 while (cur && cur->ai_next)
977 cur = cur->ai_next;
978 } else
979 ERR(EAI_FAMILY); /*xxx*/
980 }
981 break;
982 #endif
983 default:
984 if (inet_pton(afd->a_af, hostname, pton) == 1) {
985 if (pai->ai_family == afd->a_af ||
986 pai->ai_family == PF_UNSPEC /*?*/) {
987 GET_AI(cur->ai_next, afd, pton);
988 GET_PORT(cur->ai_next, servname);
989 if ((pai->ai_flags & AI_CANONNAME)) {
990 /*
991 * Set the numeric address itself as
992 * the canonical name, based on a
993 * clarification in rfc2553bis-03.
994 */
995 GET_CANONNAME(cur->ai_next, canonname);
996 }
997 while (cur->ai_next)
998 cur = cur->ai_next;
999 } else
1000 ERR(EAI_FAMILY); /*xxx*/
1001 }
1002 break;
1003 }
1004
1005 *res = sentinel.ai_next;
1006 return 0;
1007
1008 free:
1009 bad:
1010 if (sentinel.ai_next)
1011 freeaddrinfo(sentinel.ai_next);
1012 return error;
1013 }
1014
1015 /*
1016 * numeric hostname with scope
1017 */
1018 static int
explore_numeric_scope(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res)1019 explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
1020 const char *servname, struct addrinfo **res)
1021 {
1022 #if !defined(SCOPE_DELIMITER) || !defined(INET6)
1023 return explore_numeric(pai, hostname, servname, res, hostname);
1024 #else
1025 const struct afd *afd;
1026 struct addrinfo *cur;
1027 int error;
1028 char *cp, *hostname2 = NULL, *scope, *addr;
1029 struct sockaddr_in6 *sin6;
1030
1031 assert(pai != NULL);
1032 /* hostname may be NULL */
1033 /* servname may be NULL */
1034 assert(res != NULL);
1035
1036 /*
1037 * if the servname does not match socktype/protocol, ignore it.
1038 */
1039 if (get_portmatch(pai, servname) != 0)
1040 return 0;
1041
1042 afd = find_afd(pai->ai_family);
1043 if (afd == NULL)
1044 return 0;
1045
1046 if (!afd->a_scoped)
1047 return explore_numeric(pai, hostname, servname, res, hostname);
1048
1049 cp = strchr(hostname, SCOPE_DELIMITER);
1050 if (cp == NULL)
1051 return explore_numeric(pai, hostname, servname, res, hostname);
1052
1053 /*
1054 * Handle special case of <scoped_address><delimiter><scope id>
1055 */
1056 hostname2 = strdup(hostname);
1057 if (hostname2 == NULL)
1058 return EAI_MEMORY;
1059 /* terminate at the delimiter */
1060 hostname2[cp - hostname] = '\0';
1061 addr = hostname2;
1062 scope = cp + 1;
1063
1064 error = explore_numeric(pai, addr, servname, res, hostname);
1065 if (error == 0) {
1066 u_int32_t scopeid;
1067
1068 for (cur = *res; cur; cur = cur->ai_next) {
1069 if (cur->ai_family != AF_INET6)
1070 continue;
1071 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
1072 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
1073 free(hostname2);
1074 return(EAI_NODATA); /* XXX: is return OK? */
1075 }
1076 sin6->sin6_scope_id = scopeid;
1077 }
1078 }
1079
1080 free(hostname2);
1081
1082 return error;
1083 #endif
1084 }
1085
1086 static int
get_canonname(const struct addrinfo * pai,struct addrinfo * ai,const char * str)1087 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
1088 {
1089
1090 assert(pai != NULL);
1091 assert(ai != NULL);
1092 assert(str != NULL);
1093
1094 if ((pai->ai_flags & AI_CANONNAME) != 0) {
1095 ai->ai_canonname = strdup(str);
1096 if (ai->ai_canonname == NULL)
1097 return EAI_MEMORY;
1098 }
1099 return 0;
1100 }
1101
1102 static struct addrinfo *
get_ai(const struct addrinfo * pai,const struct afd * afd,const char * addr)1103 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
1104 {
1105 char *p;
1106 struct addrinfo *ai;
1107
1108 assert(pai != NULL);
1109 assert(afd != NULL);
1110 assert(addr != NULL);
1111
1112 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
1113 + (afd->a_socklen));
1114 if (ai == NULL)
1115 return NULL;
1116
1117 memcpy(ai, pai, sizeof(struct addrinfo));
1118 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1119 memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1120
1121 #ifdef HAVE_SA_LEN
1122 ai->ai_addr->sa_len = afd->a_socklen;
1123 #endif
1124
1125 ai->ai_addrlen = afd->a_socklen;
1126 #if defined (__alpha__) || (defined(__i386__) && defined(_LP64)) || defined(__sparc64__)
1127 ai->__ai_pad0 = 0;
1128 #endif
1129 ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1130 p = (char *)(void *)(ai->ai_addr);
1131 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
1132 return ai;
1133 }
1134
1135 static int
get_portmatch(const struct addrinfo * ai,const char * servname)1136 get_portmatch(const struct addrinfo *ai, const char *servname)
1137 {
1138
1139 assert(ai != NULL);
1140 /* servname may be NULL */
1141
1142 return get_port(ai, servname, 1);
1143 }
1144
1145 static int
get_port(const struct addrinfo * ai,const char * servname,int matchonly)1146 get_port(const struct addrinfo *ai, const char *servname, int matchonly)
1147 {
1148 const char *proto;
1149 struct servent *sp;
1150 int port;
1151 int allownumeric;
1152
1153 assert(ai != NULL);
1154 /* servname may be NULL */
1155
1156 if (servname == NULL)
1157 return 0;
1158 switch (ai->ai_family) {
1159 case AF_INET:
1160 #ifdef AF_INET6
1161 case AF_INET6:
1162 #endif
1163 break;
1164 default:
1165 return 0;
1166 }
1167
1168 switch (ai->ai_socktype) {
1169 case SOCK_RAW:
1170 return EAI_SERVICE;
1171 case SOCK_DGRAM:
1172 case SOCK_STREAM:
1173 allownumeric = 1;
1174 break;
1175 case ANY:
1176 #if 1 /* ANDROID-SPECIFIC CHANGE TO MATCH GLIBC */
1177 allownumeric = 1;
1178 #else
1179 allownumeric = 0;
1180 #endif
1181 break;
1182 default:
1183 return EAI_SOCKTYPE;
1184 }
1185
1186 port = str2number(servname);
1187 if (port >= 0) {
1188 if (!allownumeric)
1189 return EAI_SERVICE;
1190 if (port < 0 || port > 65535)
1191 return EAI_SERVICE;
1192 port = htons(port);
1193 } else {
1194 if (ai->ai_flags & AI_NUMERICSERV)
1195 return EAI_NONAME;
1196
1197 switch (ai->ai_socktype) {
1198 case SOCK_DGRAM:
1199 proto = "udp";
1200 break;
1201 case SOCK_STREAM:
1202 proto = "tcp";
1203 break;
1204 default:
1205 proto = NULL;
1206 break;
1207 }
1208
1209 if ((sp = getservbyname(servname, proto)) == NULL)
1210 return EAI_SERVICE;
1211 port = sp->s_port;
1212 }
1213
1214 if (!matchonly) {
1215 switch (ai->ai_family) {
1216 case AF_INET:
1217 ((struct sockaddr_in *)(void *)
1218 ai->ai_addr)->sin_port = port;
1219 break;
1220 #ifdef INET6
1221 case AF_INET6:
1222 ((struct sockaddr_in6 *)(void *)
1223 ai->ai_addr)->sin6_port = port;
1224 break;
1225 #endif
1226 }
1227 }
1228
1229 return 0;
1230 }
1231
1232 static const struct afd *
find_afd(int af)1233 find_afd(int af)
1234 {
1235 const struct afd *afd;
1236
1237 if (af == PF_UNSPEC)
1238 return NULL;
1239 for (afd = afdl; afd->a_af; afd++) {
1240 if (afd->a_af == af)
1241 return afd;
1242 }
1243 return NULL;
1244 }
1245
1246 #ifdef INET6
1247 /* convert a string to a scope identifier. XXX: IPv6 specific */
1248 static int
ip6_str2scopeid(char * scope,struct sockaddr_in6 * sin6,u_int32_t * scopeid)1249 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
1250 {
1251 u_long lscopeid;
1252 struct in6_addr *a6;
1253 char *ep;
1254
1255 assert(scope != NULL);
1256 assert(sin6 != NULL);
1257 assert(scopeid != NULL);
1258
1259 a6 = &sin6->sin6_addr;
1260
1261 /* empty scopeid portion is invalid */
1262 if (*scope == '\0')
1263 return -1;
1264
1265 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
1266 /*
1267 * We currently assume a one-to-one mapping between links
1268 * and interfaces, so we simply use interface indices for
1269 * like-local scopes.
1270 */
1271 *scopeid = if_nametoindex(scope);
1272 if (*scopeid == 0)
1273 goto trynumeric;
1274 return 0;
1275 }
1276
1277 /* still unclear about literal, allow numeric only - placeholder */
1278 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1279 goto trynumeric;
1280 if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1281 goto trynumeric;
1282 else
1283 goto trynumeric; /* global */
1284
1285 /* try to convert to a numeric id as a last resort */
1286 trynumeric:
1287 errno = 0;
1288 lscopeid = strtoul(scope, &ep, 10);
1289 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
1290 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
1291 return 0;
1292 else
1293 return -1;
1294 }
1295 #endif
1296
1297 /* code duplicate with gethnamaddr.c */
1298
1299 static const char AskedForGot[] =
1300 "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1301
1302 static struct addrinfo *
getanswer(const querybuf * answer,int anslen,const char * qname,int qtype,const struct addrinfo * pai)1303 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
1304 const struct addrinfo *pai)
1305 {
1306 struct addrinfo sentinel, *cur;
1307 struct addrinfo ai;
1308 const struct afd *afd;
1309 char *canonname;
1310 const HEADER *hp;
1311 const u_char *cp;
1312 int n;
1313 const u_char *eom;
1314 char *bp, *ep;
1315 int type, class, ancount, qdcount;
1316 int haveanswer, had_error;
1317 char tbuf[MAXDNAME];
1318 int (*name_ok) (const char *);
1319 char hostbuf[8*1024];
1320
1321 assert(answer != NULL);
1322 assert(qname != NULL);
1323 assert(pai != NULL);
1324
1325 memset(&sentinel, 0, sizeof(sentinel));
1326 cur = &sentinel;
1327
1328 canonname = NULL;
1329 eom = answer->buf + anslen;
1330 switch (qtype) {
1331 case T_A:
1332 case T_AAAA:
1333 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
1334 name_ok = res_hnok;
1335 break;
1336 default:
1337 return NULL; /* XXX should be abort(); */
1338 }
1339 /*
1340 * find first satisfactory answer
1341 */
1342 hp = &answer->hdr;
1343 ancount = ntohs(hp->ancount);
1344 qdcount = ntohs(hp->qdcount);
1345 bp = hostbuf;
1346 ep = hostbuf + sizeof hostbuf;
1347 cp = answer->buf + HFIXEDSZ;
1348 if (qdcount != 1) {
1349 h_errno = NO_RECOVERY;
1350 return (NULL);
1351 }
1352 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
1353 if ((n < 0) || !(*name_ok)(bp)) {
1354 h_errno = NO_RECOVERY;
1355 return (NULL);
1356 }
1357 cp += n + QFIXEDSZ;
1358 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
1359 /* res_send() has already verified that the query name is the
1360 * same as the one we sent; this just gets the expanded name
1361 * (i.e., with the succeeding search-domain tacked on).
1362 */
1363 n = strlen(bp) + 1; /* for the \0 */
1364 if (n >= MAXHOSTNAMELEN) {
1365 h_errno = NO_RECOVERY;
1366 return (NULL);
1367 }
1368 canonname = bp;
1369 bp += n;
1370 /* The qname can be abbreviated, but h_name is now absolute. */
1371 qname = canonname;
1372 }
1373 haveanswer = 0;
1374 had_error = 0;
1375 while (ancount-- > 0 && cp < eom && !had_error) {
1376 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
1377 if ((n < 0) || !(*name_ok)(bp)) {
1378 had_error++;
1379 continue;
1380 }
1381 cp += n; /* name */
1382 type = _getshort(cp);
1383 cp += INT16SZ; /* type */
1384 class = _getshort(cp);
1385 cp += INT16SZ + INT32SZ; /* class, TTL */
1386 n = _getshort(cp);
1387 cp += INT16SZ; /* len */
1388 if (class != C_IN) {
1389 /* XXX - debug? syslog? */
1390 cp += n;
1391 continue; /* XXX - had_error++ ? */
1392 }
1393 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
1394 type == T_CNAME) {
1395 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
1396 if ((n < 0) || !(*name_ok)(tbuf)) {
1397 had_error++;
1398 continue;
1399 }
1400 cp += n;
1401 /* Get canonical name. */
1402 n = strlen(tbuf) + 1; /* for the \0 */
1403 if (n > ep - bp || n >= MAXHOSTNAMELEN) {
1404 had_error++;
1405 continue;
1406 }
1407 strlcpy(bp, tbuf, (size_t)(ep - bp));
1408 canonname = bp;
1409 bp += n;
1410 continue;
1411 }
1412 if (qtype == T_ANY) {
1413 if (!(type == T_A || type == T_AAAA)) {
1414 cp += n;
1415 continue;
1416 }
1417 } else if (type != qtype) {
1418 if (type != T_KEY && type != T_SIG)
1419 syslog(LOG_NOTICE|LOG_AUTH,
1420 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
1421 qname, p_class(C_IN), p_type(qtype),
1422 p_type(type));
1423 cp += n;
1424 continue; /* XXX - had_error++ ? */
1425 }
1426 switch (type) {
1427 case T_A:
1428 case T_AAAA:
1429 if (strcasecmp(canonname, bp) != 0) {
1430 syslog(LOG_NOTICE|LOG_AUTH,
1431 AskedForGot, canonname, bp);
1432 cp += n;
1433 continue; /* XXX - had_error++ ? */
1434 }
1435 if (type == T_A && n != INADDRSZ) {
1436 cp += n;
1437 continue;
1438 }
1439 if (type == T_AAAA && n != IN6ADDRSZ) {
1440 cp += n;
1441 continue;
1442 }
1443 if (type == T_AAAA) {
1444 struct in6_addr in6;
1445 memcpy(&in6, cp, IN6ADDRSZ);
1446 if (IN6_IS_ADDR_V4MAPPED(&in6)) {
1447 cp += n;
1448 continue;
1449 }
1450 }
1451 if (!haveanswer) {
1452 int nn;
1453
1454 canonname = bp;
1455 nn = strlen(bp) + 1; /* for the \0 */
1456 bp += nn;
1457 }
1458
1459 /* don't overwrite pai */
1460 ai = *pai;
1461 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
1462 afd = find_afd(ai.ai_family);
1463 if (afd == NULL) {
1464 cp += n;
1465 continue;
1466 }
1467 cur->ai_next = get_ai(&ai, afd, (const char *)cp);
1468 if (cur->ai_next == NULL)
1469 had_error++;
1470 while (cur && cur->ai_next)
1471 cur = cur->ai_next;
1472 cp += n;
1473 break;
1474 default:
1475 abort();
1476 }
1477 if (!had_error)
1478 haveanswer++;
1479 }
1480 if (haveanswer) {
1481 if (!canonname)
1482 (void)get_canonname(pai, sentinel.ai_next, qname);
1483 else
1484 (void)get_canonname(pai, sentinel.ai_next, canonname);
1485 h_errno = NETDB_SUCCESS;
1486 return sentinel.ai_next;
1487 }
1488
1489 h_errno = NO_RECOVERY;
1490 return NULL;
1491 }
1492
1493 struct addrinfo_sort_elem {
1494 struct addrinfo *ai;
1495 int has_src_addr;
1496 sockaddr_union src_addr;
1497 int original_order;
1498 };
1499
1500 /*ARGSUSED*/
1501 static int
_get_scope(const struct sockaddr * addr)1502 _get_scope(const struct sockaddr *addr)
1503 {
1504 if (addr->sa_family == AF_INET6) {
1505 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1506 if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) {
1507 return IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr);
1508 } else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) ||
1509 IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) {
1510 /*
1511 * RFC 4291 section 2.5.3 says loopback is to be treated as having
1512 * link-local scope.
1513 */
1514 return IPV6_ADDR_SCOPE_LINKLOCAL;
1515 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
1516 return IPV6_ADDR_SCOPE_SITELOCAL;
1517 } else {
1518 return IPV6_ADDR_SCOPE_GLOBAL;
1519 }
1520 } else if (addr->sa_family == AF_INET) {
1521 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
1522 unsigned long int na = ntohl(addr4->sin_addr.s_addr);
1523
1524 if (IN_LOOPBACK(na) || /* 127.0.0.0/8 */
1525 (na & 0xffff0000) == 0xa9fe0000) { /* 169.254.0.0/16 */
1526 return IPV6_ADDR_SCOPE_LINKLOCAL;
1527 } else {
1528 /*
1529 * RFC 6724 section 3.2. Other IPv4 addresses, including private addresses
1530 * and shared addresses (100.64.0.0/10), are assigned global scope.
1531 */
1532 return IPV6_ADDR_SCOPE_GLOBAL;
1533 }
1534 } else {
1535 /*
1536 * This should never happen.
1537 * Return a scope with low priority as a last resort.
1538 */
1539 return IPV6_ADDR_SCOPE_NODELOCAL;
1540 }
1541 }
1542
1543 /* These macros are modelled after the ones in <netinet/in6.h>. */
1544
1545 /* RFC 4380, section 2.6 */
1546 #define IN6_IS_ADDR_TEREDO(a) \
1547 ((*(const uint32_t *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000)))
1548
1549 /* RFC 3056, section 2. */
1550 #define IN6_IS_ADDR_6TO4(a) \
1551 (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02))
1552
1553 /* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */
1554 #define IN6_IS_ADDR_6BONE(a) \
1555 (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe))
1556
1557 /*
1558 * Get the label for a given IPv4/IPv6 address.
1559 * RFC 6724, section 2.1.
1560 */
1561
1562 /*ARGSUSED*/
1563 static int
_get_label(const struct sockaddr * addr)1564 _get_label(const struct sockaddr *addr)
1565 {
1566 if (addr->sa_family == AF_INET) {
1567 return 4;
1568 } else if (addr->sa_family == AF_INET6) {
1569 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *) addr;
1570 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
1571 return 0;
1572 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
1573 return 4;
1574 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
1575 return 2;
1576 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
1577 return 5;
1578 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
1579 return 13;
1580 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) {
1581 return 3;
1582 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
1583 return 11;
1584 } else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
1585 return 12;
1586 } else {
1587 /* All other IPv6 addresses, including global unicast addresses. */
1588 return 1;
1589 }
1590 } else {
1591 /*
1592 * This should never happen.
1593 * Return a semi-random label as a last resort.
1594 */
1595 return 1;
1596 }
1597 }
1598
1599 /*
1600 * Get the precedence for a given IPv4/IPv6 address.
1601 * RFC 6724, section 2.1.
1602 */
1603
1604 /*ARGSUSED*/
1605 static int
_get_precedence(const struct sockaddr * addr)1606 _get_precedence(const struct sockaddr *addr)
1607 {
1608 if (addr->sa_family == AF_INET) {
1609 return 35;
1610 } else if (addr->sa_family == AF_INET6) {
1611 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1612 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
1613 return 50;
1614 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
1615 return 35;
1616 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
1617 return 30;
1618 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
1619 return 5;
1620 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
1621 return 3;
1622 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) ||
1623 IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) ||
1624 IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
1625 return 1;
1626 } else {
1627 /* All other IPv6 addresses, including global unicast addresses. */
1628 return 40;
1629 }
1630 } else {
1631 return 1;
1632 }
1633 }
1634
1635 /*
1636 * Find number of matching initial bits between the two addresses a1 and a2.
1637 */
1638
1639 /*ARGSUSED*/
1640 static int
_common_prefix_len(const struct in6_addr * a1,const struct in6_addr * a2)1641 _common_prefix_len(const struct in6_addr *a1, const struct in6_addr *a2)
1642 {
1643 const char *p1 = (const char *)a1;
1644 const char *p2 = (const char *)a2;
1645 unsigned i;
1646
1647 for (i = 0; i < sizeof(*a1); ++i) {
1648 int x, j;
1649
1650 if (p1[i] == p2[i]) {
1651 continue;
1652 }
1653 x = p1[i] ^ p2[i];
1654 for (j = 0; j < CHAR_BIT; ++j) {
1655 if (x & (1 << (CHAR_BIT - 1))) {
1656 return i * CHAR_BIT + j;
1657 }
1658 x <<= 1;
1659 }
1660 }
1661 return sizeof(*a1) * CHAR_BIT;
1662 }
1663
1664 /*
1665 * Compare two source/destination address pairs.
1666 * RFC 6724, section 6.
1667 */
1668
1669 /*ARGSUSED*/
1670 static int
_rfc6724_compare(const void * ptr1,const void * ptr2)1671 _rfc6724_compare(const void *ptr1, const void* ptr2)
1672 {
1673 const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1;
1674 const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2;
1675 int scope_src1, scope_dst1, scope_match1;
1676 int scope_src2, scope_dst2, scope_match2;
1677 int label_src1, label_dst1, label_match1;
1678 int label_src2, label_dst2, label_match2;
1679 int precedence1, precedence2;
1680 int prefixlen1, prefixlen2;
1681
1682 /* Rule 1: Avoid unusable destinations. */
1683 if (a1->has_src_addr != a2->has_src_addr) {
1684 return a2->has_src_addr - a1->has_src_addr;
1685 }
1686
1687 /* Rule 2: Prefer matching scope. */
1688 scope_src1 = _get_scope(&a1->src_addr.generic);
1689 scope_dst1 = _get_scope(a1->ai->ai_addr);
1690 scope_match1 = (scope_src1 == scope_dst1);
1691
1692 scope_src2 = _get_scope(&a2->src_addr.generic);
1693 scope_dst2 = _get_scope(a2->ai->ai_addr);
1694 scope_match2 = (scope_src2 == scope_dst2);
1695
1696 if (scope_match1 != scope_match2) {
1697 return scope_match2 - scope_match1;
1698 }
1699
1700 /*
1701 * Rule 3: Avoid deprecated addresses.
1702 * TODO(sesse): We don't currently have a good way of finding this.
1703 */
1704
1705 /*
1706 * Rule 4: Prefer home addresses.
1707 * TODO(sesse): We don't currently have a good way of finding this.
1708 */
1709
1710 /* Rule 5: Prefer matching label. */
1711 label_src1 = _get_label(&a1->src_addr.generic);
1712 label_dst1 = _get_label(a1->ai->ai_addr);
1713 label_match1 = (label_src1 == label_dst1);
1714
1715 label_src2 = _get_label(&a2->src_addr.generic);
1716 label_dst2 = _get_label(a2->ai->ai_addr);
1717 label_match2 = (label_src2 == label_dst2);
1718
1719 if (label_match1 != label_match2) {
1720 return label_match2 - label_match1;
1721 }
1722
1723 /* Rule 6: Prefer higher precedence. */
1724 precedence1 = _get_precedence(a1->ai->ai_addr);
1725 precedence2 = _get_precedence(a2->ai->ai_addr);
1726 if (precedence1 != precedence2) {
1727 return precedence2 - precedence1;
1728 }
1729
1730 /*
1731 * Rule 7: Prefer native transport.
1732 * TODO(sesse): We don't currently have a good way of finding this.
1733 */
1734
1735 /* Rule 8: Prefer smaller scope. */
1736 if (scope_dst1 != scope_dst2) {
1737 return scope_dst1 - scope_dst2;
1738 }
1739
1740 /*
1741 * Rule 9: Use longest matching prefix.
1742 * We implement this for IPv6 only, as the rules in RFC 6724 don't seem
1743 * to work very well directly applied to IPv4. (glibc uses information from
1744 * the routing table for a custom IPv4 implementation here.)
1745 */
1746 if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 &&
1747 a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6) {
1748 const struct sockaddr_in6 *a1_src = &a1->src_addr.in6;
1749 const struct sockaddr_in6 *a1_dst = (const struct sockaddr_in6 *)a1->ai->ai_addr;
1750 const struct sockaddr_in6 *a2_src = &a2->src_addr.in6;
1751 const struct sockaddr_in6 *a2_dst = (const struct sockaddr_in6 *)a2->ai->ai_addr;
1752 prefixlen1 = _common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr);
1753 prefixlen2 = _common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr);
1754 if (prefixlen1 != prefixlen2) {
1755 return prefixlen2 - prefixlen1;
1756 }
1757 }
1758
1759 /*
1760 * Rule 10: Leave the order unchanged.
1761 * We need this since qsort() is not necessarily stable.
1762 */
1763 return a1->original_order - a2->original_order;
1764 }
1765
1766 /*
1767 * Find the source address that will be used if trying to connect to the given
1768 * address. src_addr must be large enough to hold a struct sockaddr_in6.
1769 *
1770 * Returns 1 if a source address was found, 0 if the address is unreachable,
1771 * and -1 if a fatal error occurred. If 0 or 1, the contents of src_addr are
1772 * undefined.
1773 */
1774
1775 /*ARGSUSED*/
1776 static int
_find_src_addr(const struct sockaddr * addr,struct sockaddr * src_addr,unsigned mark)1777 _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned mark)
1778 {
1779 int sock;
1780 int ret;
1781 socklen_t len;
1782
1783 switch (addr->sa_family) {
1784 case AF_INET:
1785 len = sizeof(struct sockaddr_in);
1786 break;
1787 case AF_INET6:
1788 len = sizeof(struct sockaddr_in6);
1789 break;
1790 default:
1791 /* No known usable source address for non-INET families. */
1792 return 0;
1793 }
1794
1795 sock = socket(addr->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
1796 if (sock == -1) {
1797 if (errno == EAFNOSUPPORT) {
1798 return 0;
1799 } else {
1800 return -1;
1801 }
1802 }
1803 if (mark != MARK_UNSET && setsockopt(sock, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0)
1804 return 0;
1805 do {
1806 ret = __connect(sock, addr, len);
1807 } while (ret == -1 && errno == EINTR);
1808
1809 if (ret == -1) {
1810 close(sock);
1811 return 0;
1812 }
1813
1814 if (getsockname(sock, src_addr, &len) == -1) {
1815 close(sock);
1816 return -1;
1817 }
1818 close(sock);
1819 return 1;
1820 }
1821
1822 /*
1823 * Sort the linked list starting at sentinel->ai_next in RFC6724 order.
1824 * Will leave the list unchanged if an error occurs.
1825 */
1826
1827 /*ARGSUSED*/
1828 static void
_rfc6724_sort(struct addrinfo * list_sentinel,unsigned mark)1829 _rfc6724_sort(struct addrinfo *list_sentinel, unsigned mark)
1830 {
1831 struct addrinfo *cur;
1832 int nelem = 0, i;
1833 struct addrinfo_sort_elem *elems;
1834
1835 cur = list_sentinel->ai_next;
1836 while (cur) {
1837 ++nelem;
1838 cur = cur->ai_next;
1839 }
1840
1841 elems = (struct addrinfo_sort_elem *)malloc(nelem * sizeof(struct addrinfo_sort_elem));
1842 if (elems == NULL) {
1843 goto error;
1844 }
1845
1846 /*
1847 * Convert the linked list to an array that also contains the candidate
1848 * source address for each destination address.
1849 */
1850 for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) {
1851 int has_src_addr;
1852 assert(cur != NULL);
1853 elems[i].ai = cur;
1854 elems[i].original_order = i;
1855
1856 has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic, mark);
1857 if (has_src_addr == -1) {
1858 goto error;
1859 }
1860 elems[i].has_src_addr = has_src_addr;
1861 }
1862
1863 /* Sort the addresses, and rearrange the linked list so it matches the sorted order. */
1864 qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem), _rfc6724_compare);
1865
1866 list_sentinel->ai_next = elems[0].ai;
1867 for (i = 0; i < nelem - 1; ++i) {
1868 elems[i].ai->ai_next = elems[i + 1].ai;
1869 }
1870 elems[nelem - 1].ai->ai_next = NULL;
1871
1872 error:
1873 free(elems);
1874 }
1875
1876 /*ARGSUSED*/
1877 static int
_dns_getaddrinfo(void * rv,void * cb_data,va_list ap)1878 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
1879 {
1880 struct addrinfo *ai;
1881 querybuf *buf, *buf2;
1882 const char *name;
1883 const struct addrinfo *pai;
1884 struct addrinfo sentinel, *cur;
1885 struct res_target q, q2;
1886 res_state res;
1887 unsigned netid, mark;
1888
1889 name = va_arg(ap, char *);
1890 pai = va_arg(ap, const struct addrinfo *);
1891 netid = va_arg(ap, unsigned);
1892 mark = va_arg(ap, unsigned);
1893 //fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name);
1894
1895 memset(&q, 0, sizeof(q));
1896 memset(&q2, 0, sizeof(q2));
1897 memset(&sentinel, 0, sizeof(sentinel));
1898 cur = &sentinel;
1899
1900 buf = malloc(sizeof(*buf));
1901 if (buf == NULL) {
1902 h_errno = NETDB_INTERNAL;
1903 return NS_NOTFOUND;
1904 }
1905 buf2 = malloc(sizeof(*buf2));
1906 if (buf2 == NULL) {
1907 free(buf);
1908 h_errno = NETDB_INTERNAL;
1909 return NS_NOTFOUND;
1910 }
1911
1912 switch (pai->ai_family) {
1913 case AF_UNSPEC:
1914 /* prefer IPv6 */
1915 q.name = name;
1916 q.qclass = C_IN;
1917 q.answer = buf->buf;
1918 q.anslen = sizeof(buf->buf);
1919 int query_ipv6 = 1, query_ipv4 = 1;
1920 if (pai->ai_flags & AI_ADDRCONFIG) {
1921 query_ipv6 = _have_ipv6(mark);
1922 query_ipv4 = _have_ipv4(mark);
1923 }
1924 if (query_ipv6) {
1925 q.qtype = T_AAAA;
1926 if (query_ipv4) {
1927 q.next = &q2;
1928 q2.name = name;
1929 q2.qclass = C_IN;
1930 q2.qtype = T_A;
1931 q2.answer = buf2->buf;
1932 q2.anslen = sizeof(buf2->buf);
1933 }
1934 } else if (query_ipv4) {
1935 q.qtype = T_A;
1936 } else {
1937 free(buf);
1938 free(buf2);
1939 return NS_NOTFOUND;
1940 }
1941 break;
1942 case AF_INET:
1943 q.name = name;
1944 q.qclass = C_IN;
1945 q.qtype = T_A;
1946 q.answer = buf->buf;
1947 q.anslen = sizeof(buf->buf);
1948 break;
1949 case AF_INET6:
1950 q.name = name;
1951 q.qclass = C_IN;
1952 q.qtype = T_AAAA;
1953 q.answer = buf->buf;
1954 q.anslen = sizeof(buf->buf);
1955 break;
1956 default:
1957 free(buf);
1958 free(buf2);
1959 return NS_UNAVAIL;
1960 }
1961
1962 res = __res_get_state();
1963 if (res == NULL) {
1964 free(buf);
1965 free(buf2);
1966 return NS_NOTFOUND;
1967 }
1968
1969 /* this just sets our netid val in the thread private data so we don't have to
1970 * modify the api's all the way down to res_send.c's res_nsend. We could
1971 * fully populate the thread private data here, but if we get down there
1972 * and have a cache hit that would be wasted, so we do the rest there on miss
1973 */
1974 res_setnetid(res, netid);
1975 res_setmark(res, mark);
1976 if (res_searchN(name, &q, res) < 0) {
1977 __res_put_state(res);
1978 free(buf);
1979 free(buf2);
1980 return NS_NOTFOUND;
1981 }
1982 ai = getanswer(buf, q.n, q.name, q.qtype, pai);
1983 if (ai) {
1984 cur->ai_next = ai;
1985 while (cur && cur->ai_next)
1986 cur = cur->ai_next;
1987 }
1988 if (q.next) {
1989 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai);
1990 if (ai)
1991 cur->ai_next = ai;
1992 }
1993 free(buf);
1994 free(buf2);
1995 if (sentinel.ai_next == NULL) {
1996 __res_put_state(res);
1997 switch (h_errno) {
1998 case HOST_NOT_FOUND:
1999 return NS_NOTFOUND;
2000 case TRY_AGAIN:
2001 return NS_TRYAGAIN;
2002 default:
2003 return NS_UNAVAIL;
2004 }
2005 }
2006
2007 _rfc6724_sort(&sentinel, netid);
2008
2009 __res_put_state(res);
2010
2011 *((struct addrinfo **)rv) = sentinel.ai_next;
2012 return NS_SUCCESS;
2013 }
2014
2015 static void
_sethtent(FILE ** hostf)2016 _sethtent(FILE **hostf)
2017 {
2018
2019 if (!*hostf)
2020 *hostf = fopen(_PATH_HOSTS, "r" );
2021 else
2022 rewind(*hostf);
2023 }
2024
2025 static void
_endhtent(FILE ** hostf)2026 _endhtent(FILE **hostf)
2027 {
2028
2029 if (*hostf) {
2030 (void) fclose(*hostf);
2031 *hostf = NULL;
2032 }
2033 }
2034
2035 static struct addrinfo *
_gethtent(FILE ** hostf,const char * name,const struct addrinfo * pai)2036 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai)
2037 {
2038 char *p;
2039 char *cp, *tname, *cname;
2040 struct addrinfo hints, *res0, *res;
2041 int error;
2042 const char *addr;
2043 char hostbuf[8*1024];
2044
2045 // fprintf(stderr, "_gethtent() name = '%s'\n", name);
2046 assert(name != NULL);
2047 assert(pai != NULL);
2048
2049 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "r" )))
2050 return (NULL);
2051 again:
2052 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf)))
2053 return (NULL);
2054 if (*p == '#')
2055 goto again;
2056 if (!(cp = strpbrk(p, "#\n")))
2057 goto again;
2058 *cp = '\0';
2059 if (!(cp = strpbrk(p, " \t")))
2060 goto again;
2061 *cp++ = '\0';
2062 addr = p;
2063 /* if this is not something we're looking for, skip it. */
2064 cname = NULL;
2065 while (cp && *cp) {
2066 if (*cp == ' ' || *cp == '\t') {
2067 cp++;
2068 continue;
2069 }
2070 if (!cname)
2071 cname = cp;
2072 tname = cp;
2073 if ((cp = strpbrk(cp, " \t")) != NULL)
2074 *cp++ = '\0';
2075 // fprintf(stderr, "\ttname = '%s'", tname);
2076 if (strcasecmp(name, tname) == 0)
2077 goto found;
2078 }
2079 goto again;
2080
2081 found:
2082 hints = *pai;
2083 hints.ai_flags = AI_NUMERICHOST;
2084 error = getaddrinfo(addr, NULL, &hints, &res0);
2085 if (error)
2086 goto again;
2087 for (res = res0; res; res = res->ai_next) {
2088 /* cover it up */
2089 res->ai_flags = pai->ai_flags;
2090
2091 if (pai->ai_flags & AI_CANONNAME) {
2092 if (get_canonname(pai, res, cname) != 0) {
2093 freeaddrinfo(res0);
2094 goto again;
2095 }
2096 }
2097 }
2098 return res0;
2099 }
2100
2101 /*ARGSUSED*/
2102 static int
_files_getaddrinfo(void * rv,void * cb_data,va_list ap)2103 _files_getaddrinfo(void *rv, void *cb_data, va_list ap)
2104 {
2105 const char *name;
2106 const struct addrinfo *pai;
2107 struct addrinfo sentinel, *cur;
2108 struct addrinfo *p;
2109 FILE *hostf = NULL;
2110
2111 name = va_arg(ap, char *);
2112 pai = va_arg(ap, struct addrinfo *);
2113
2114 // fprintf(stderr, "_files_getaddrinfo() name = '%s'\n", name);
2115 memset(&sentinel, 0, sizeof(sentinel));
2116 cur = &sentinel;
2117
2118 _sethtent(&hostf);
2119 while ((p = _gethtent(&hostf, name, pai)) != NULL) {
2120 cur->ai_next = p;
2121 while (cur && cur->ai_next)
2122 cur = cur->ai_next;
2123 }
2124 _endhtent(&hostf);
2125
2126 *((struct addrinfo **)rv) = sentinel.ai_next;
2127 if (sentinel.ai_next == NULL)
2128 return NS_NOTFOUND;
2129 return NS_SUCCESS;
2130 }
2131
2132 /* resolver logic */
2133
2134 /*
2135 * Formulate a normal query, send, and await answer.
2136 * Returned answer is placed in supplied buffer "answer".
2137 * Perform preliminary check of answer, returning success only
2138 * if no error is indicated and the answer count is nonzero.
2139 * Return the size of the response on success, -1 on error.
2140 * Error number is left in h_errno.
2141 *
2142 * Caller must parse answer and determine whether it answers the question.
2143 */
2144 static int
res_queryN(const char * name,struct res_target * target,res_state res)2145 res_queryN(const char *name, /* domain name */ struct res_target *target,
2146 res_state res)
2147 {
2148 u_char buf[MAXPACKET];
2149 HEADER *hp;
2150 int n;
2151 struct res_target *t;
2152 int rcode;
2153 int ancount;
2154
2155 assert(name != NULL);
2156 /* XXX: target may be NULL??? */
2157
2158 rcode = NOERROR;
2159 ancount = 0;
2160
2161 for (t = target; t; t = t->next) {
2162 int class, type;
2163 u_char *answer;
2164 int anslen;
2165
2166 hp = (HEADER *)(void *)t->answer;
2167 hp->rcode = NOERROR; /* default */
2168
2169 /* make it easier... */
2170 class = t->qclass;
2171 type = t->qtype;
2172 answer = t->answer;
2173 anslen = t->anslen;
2174 #ifdef DEBUG
2175 if (res->options & RES_DEBUG)
2176 printf(";; res_nquery(%s, %d, %d)\n", name, class, type);
2177 #endif
2178
2179 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
2180 buf, sizeof(buf));
2181 #ifdef RES_USE_EDNS0
2182 if (n > 0 && (res->options & RES_USE_EDNS0) != 0)
2183 n = res_nopt(res, n, buf, sizeof(buf), anslen);
2184 #endif
2185 if (n <= 0) {
2186 #ifdef DEBUG
2187 if (res->options & RES_DEBUG)
2188 printf(";; res_nquery: mkquery failed\n");
2189 #endif
2190 h_errno = NO_RECOVERY;
2191 return n;
2192 }
2193 n = res_nsend(res, buf, n, answer, anslen);
2194 #if 0
2195 if (n < 0) {
2196 #ifdef DEBUG
2197 if (res->options & RES_DEBUG)
2198 printf(";; res_query: send error\n");
2199 #endif
2200 h_errno = TRY_AGAIN;
2201 return n;
2202 }
2203 #endif
2204
2205 if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
2206 rcode = hp->rcode; /* record most recent error */
2207 #ifdef DEBUG
2208 if (res->options & RES_DEBUG)
2209 printf(";; rcode = %u, ancount=%u\n", hp->rcode,
2210 ntohs(hp->ancount));
2211 #endif
2212 continue;
2213 }
2214
2215 ancount += ntohs(hp->ancount);
2216
2217 t->n = n;
2218 }
2219
2220 if (ancount == 0) {
2221 switch (rcode) {
2222 case NXDOMAIN:
2223 h_errno = HOST_NOT_FOUND;
2224 break;
2225 case SERVFAIL:
2226 h_errno = TRY_AGAIN;
2227 break;
2228 case NOERROR:
2229 h_errno = NO_DATA;
2230 break;
2231 case FORMERR:
2232 case NOTIMP:
2233 case REFUSED:
2234 default:
2235 h_errno = NO_RECOVERY;
2236 break;
2237 }
2238 return -1;
2239 }
2240 return ancount;
2241 }
2242
2243 /*
2244 * Formulate a normal query, send, and retrieve answer in supplied buffer.
2245 * Return the size of the response on success, -1 on error.
2246 * If enabled, implement search rules until answer or unrecoverable failure
2247 * is detected. Error code, if any, is left in h_errno.
2248 */
2249 static int
res_searchN(const char * name,struct res_target * target,res_state res)2250 res_searchN(const char *name, struct res_target *target, res_state res)
2251 {
2252 const char *cp, * const *domain;
2253 HEADER *hp;
2254 u_int dots;
2255 int trailing_dot, ret, saved_herrno;
2256 int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
2257
2258 assert(name != NULL);
2259 assert(target != NULL);
2260
2261 hp = (HEADER *)(void *)target->answer; /*XXX*/
2262
2263 errno = 0;
2264 h_errno = HOST_NOT_FOUND; /* default, if we never query */
2265 dots = 0;
2266 for (cp = name; *cp; cp++)
2267 dots += (*cp == '.');
2268 trailing_dot = 0;
2269 if (cp > name && *--cp == '.')
2270 trailing_dot++;
2271
2272
2273 //fprintf(stderr, "res_searchN() name = '%s'\n", name);
2274
2275 /*
2276 * if there aren't any dots, it could be a user-level alias
2277 */
2278 if (!dots && (cp = __hostalias(name)) != NULL) {
2279 ret = res_queryN(cp, target, res);
2280 return ret;
2281 }
2282
2283 /*
2284 * If there are dots in the name already, let's just give it a try
2285 * 'as is'. The threshold can be set with the "ndots" option.
2286 */
2287 saved_herrno = -1;
2288 if (dots >= res->ndots) {
2289 ret = res_querydomainN(name, NULL, target, res);
2290 if (ret > 0)
2291 return (ret);
2292 saved_herrno = h_errno;
2293 tried_as_is++;
2294 }
2295
2296 /*
2297 * We do at least one level of search if
2298 * - there is no dot and RES_DEFNAME is set, or
2299 * - there is at least one dot, there is no trailing dot,
2300 * and RES_DNSRCH is set.
2301 */
2302 if ((!dots && (res->options & RES_DEFNAMES)) ||
2303 (dots && !trailing_dot && (res->options & RES_DNSRCH))) {
2304 int done = 0;
2305
2306 /* Unfortunately we need to set stuff up before
2307 * the domain stuff is tried. Will have a better
2308 * fix after thread pools are used.
2309 */
2310 _resolv_populate_res_for_net(res);
2311
2312 for (domain = (const char * const *)res->dnsrch;
2313 *domain && !done;
2314 domain++) {
2315
2316 ret = res_querydomainN(name, *domain, target, res);
2317 if (ret > 0)
2318 return ret;
2319
2320 /*
2321 * If no server present, give up.
2322 * If name isn't found in this domain,
2323 * keep trying higher domains in the search list
2324 * (if that's enabled).
2325 * On a NO_DATA error, keep trying, otherwise
2326 * a wildcard entry of another type could keep us
2327 * from finding this entry higher in the domain.
2328 * If we get some other error (negative answer or
2329 * server failure), then stop searching up,
2330 * but try the input name below in case it's
2331 * fully-qualified.
2332 */
2333 if (errno == ECONNREFUSED) {
2334 h_errno = TRY_AGAIN;
2335 return -1;
2336 }
2337
2338 switch (h_errno) {
2339 case NO_DATA:
2340 got_nodata++;
2341 /* FALLTHROUGH */
2342 case HOST_NOT_FOUND:
2343 /* keep trying */
2344 break;
2345 case TRY_AGAIN:
2346 if (hp->rcode == SERVFAIL) {
2347 /* try next search element, if any */
2348 got_servfail++;
2349 break;
2350 }
2351 /* FALLTHROUGH */
2352 default:
2353 /* anything else implies that we're done */
2354 done++;
2355 }
2356 /*
2357 * if we got here for some reason other than DNSRCH,
2358 * we only wanted one iteration of the loop, so stop.
2359 */
2360 if (!(res->options & RES_DNSRCH))
2361 done++;
2362 }
2363 }
2364
2365 /*
2366 * if we have not already tried the name "as is", do that now.
2367 * note that we do this regardless of how many dots were in the
2368 * name or whether it ends with a dot.
2369 */
2370 if (!tried_as_is) {
2371 ret = res_querydomainN(name, NULL, target, res);
2372 if (ret > 0)
2373 return ret;
2374 }
2375
2376 /*
2377 * if we got here, we didn't satisfy the search.
2378 * if we did an initial full query, return that query's h_errno
2379 * (note that we wouldn't be here if that query had succeeded).
2380 * else if we ever got a nodata, send that back as the reason.
2381 * else send back meaningless h_errno, that being the one from
2382 * the last DNSRCH we did.
2383 */
2384 if (saved_herrno != -1)
2385 h_errno = saved_herrno;
2386 else if (got_nodata)
2387 h_errno = NO_DATA;
2388 else if (got_servfail)
2389 h_errno = TRY_AGAIN;
2390 return -1;
2391 }
2392
2393 /*
2394 * Perform a call on res_query on the concatenation of name and domain,
2395 * removing a trailing dot from name if domain is NULL.
2396 */
2397 static int
res_querydomainN(const char * name,const char * domain,struct res_target * target,res_state res)2398 res_querydomainN(const char *name, const char *domain,
2399 struct res_target *target, res_state res)
2400 {
2401 char nbuf[MAXDNAME];
2402 const char *longname = nbuf;
2403 size_t n, d;
2404
2405 assert(name != NULL);
2406 /* XXX: target may be NULL??? */
2407
2408 #ifdef DEBUG
2409 if (res->options & RES_DEBUG)
2410 printf(";; res_querydomain(%s, %s)\n",
2411 name, domain?domain:"<Nil>");
2412 #endif
2413 if (domain == NULL) {
2414 /*
2415 * Check for trailing '.';
2416 * copy without '.' if present.
2417 */
2418 n = strlen(name);
2419 if (n + 1 > sizeof(nbuf)) {
2420 h_errno = NO_RECOVERY;
2421 return -1;
2422 }
2423 if (n > 0 && name[--n] == '.') {
2424 strncpy(nbuf, name, n);
2425 nbuf[n] = '\0';
2426 } else
2427 longname = name;
2428 } else {
2429 n = strlen(name);
2430 d = strlen(domain);
2431 if (n + 1 + d + 1 > sizeof(nbuf)) {
2432 h_errno = NO_RECOVERY;
2433 return -1;
2434 }
2435 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
2436 }
2437 return res_queryN(longname, target, res);
2438 }
2439