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 **, const struct android_net_context *);
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 static int _find_src_addr(const struct sockaddr *, struct sockaddr *, unsigned , uid_t);
248
249 static int res_queryN(const char *, struct res_target *, res_state);
250 static int res_searchN(const char *, struct res_target *, res_state);
251 static int res_querydomainN(const char *, const char *,
252 struct res_target *, res_state);
253
254 static const char * const ai_errlist[] = {
255 "Success",
256 "Address family for hostname not supported", /* EAI_ADDRFAMILY */
257 "Temporary failure in name resolution", /* EAI_AGAIN */
258 "Invalid value for ai_flags", /* EAI_BADFLAGS */
259 "Non-recoverable failure in name resolution", /* EAI_FAIL */
260 "ai_family not supported", /* EAI_FAMILY */
261 "Memory allocation failure", /* EAI_MEMORY */
262 "No address associated with hostname", /* EAI_NODATA */
263 "hostname nor servname provided, or not known", /* EAI_NONAME */
264 "servname not supported for ai_socktype", /* EAI_SERVICE */
265 "ai_socktype not supported", /* EAI_SOCKTYPE */
266 "System error returned in errno", /* EAI_SYSTEM */
267 "Invalid value for hints", /* EAI_BADHINTS */
268 "Resolved protocol is unknown", /* EAI_PROTOCOL */
269 "Argument buffer overflow", /* EAI_OVERFLOW */
270 "Unknown error", /* EAI_MAX */
271 };
272
273 /* XXX macros that make external reference is BAD. */
274
275 #define GET_AI(ai, afd, addr) \
276 do { \
277 /* external reference: pai, error, and label free */ \
278 (ai) = get_ai(pai, (afd), (addr)); \
279 if ((ai) == NULL) { \
280 error = EAI_MEMORY; \
281 goto free; \
282 } \
283 } while (/*CONSTCOND*/0)
284
285 #define GET_PORT(ai, serv) \
286 do { \
287 /* external reference: error and label free */ \
288 error = get_port((ai), (serv), 0); \
289 if (error != 0) \
290 goto free; \
291 } while (/*CONSTCOND*/0)
292
293 #define GET_CANONNAME(ai, str) \
294 do { \
295 /* external reference: pai, error and label free */ \
296 error = get_canonname(pai, (ai), (str)); \
297 if (error != 0) \
298 goto free; \
299 } while (/*CONSTCOND*/0)
300
301 #define ERR(err) \
302 do { \
303 /* external reference: error, and label bad */ \
304 error = (err); \
305 goto bad; \
306 /*NOTREACHED*/ \
307 } while (/*CONSTCOND*/0)
308
309 #define MATCH_FAMILY(x, y, w) \
310 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || \
311 (y) == PF_UNSPEC)))
312 #define MATCH(x, y, w) \
313 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
314
315 const char *
gai_strerror(int ecode)316 gai_strerror(int ecode)
317 {
318 if (ecode < 0 || ecode > EAI_MAX)
319 ecode = EAI_MAX;
320 return ai_errlist[ecode];
321 }
322
323 void
freeaddrinfo(struct addrinfo * ai)324 freeaddrinfo(struct addrinfo *ai)
325 {
326 struct addrinfo *next;
327
328 #if __ANDROID__
329 if (ai == NULL) return;
330 #else
331 _DIAGASSERT(ai != NULL);
332 #endif
333
334 do {
335 next = ai->ai_next;
336 if (ai->ai_canonname)
337 free(ai->ai_canonname);
338 /* no need to free(ai->ai_addr) */
339 free(ai);
340 ai = next;
341 } while (ai);
342 }
343
344 static int
str2number(const char * p)345 str2number(const char *p)
346 {
347 char *ep;
348 unsigned long v;
349
350 assert(p != NULL);
351
352 if (*p == '\0')
353 return -1;
354 ep = NULL;
355 errno = 0;
356 v = strtoul(p, &ep, 10);
357 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX)
358 return v;
359 else
360 return -1;
361 }
362
363 /*
364 * The following functions determine whether IPv4 or IPv6 connectivity is
365 * available in order to implement AI_ADDRCONFIG.
366 *
367 * Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is
368 * available, but whether addresses of the specified family are "configured
369 * on the local system". However, bionic doesn't currently support getifaddrs,
370 * so checking for connectivity is the next best thing.
371 */
372 static int
_have_ipv6(unsigned mark,uid_t uid)373 _have_ipv6(unsigned mark, uid_t uid) {
374 static const struct sockaddr_in6 sin6_test = {
375 .sin6_family = AF_INET6,
376 .sin6_addr.s6_addr = { // 2000::
377 0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
378 };
379 sockaddr_union addr = { .in6 = sin6_test };
380 return _find_src_addr(&addr.generic, NULL, mark, uid) == 1;
381 }
382
383 static int
_have_ipv4(unsigned mark,uid_t uid)384 _have_ipv4(unsigned mark, uid_t uid) {
385 static const struct sockaddr_in sin_test = {
386 .sin_family = AF_INET,
387 .sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8
388 };
389 sockaddr_union addr = { .in = sin_test };
390 return _find_src_addr(&addr.generic, NULL, mark, uid) == 1;
391 }
392
readBE32(FILE * fp,int32_t * result)393 bool readBE32(FILE* fp, int32_t* result) {
394 int32_t tmp;
395 if (fread(&tmp, sizeof(tmp), 1, fp) != 1) {
396 return false;
397 }
398 *result = ntohl(tmp);
399 return true;
400 }
401
402 // Returns 0 on success, else returns on error.
403 static int
android_getaddrinfo_proxy(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res,unsigned netid)404 android_getaddrinfo_proxy(
405 const char *hostname, const char *servname,
406 const struct addrinfo *hints, struct addrinfo **res, unsigned netid)
407 {
408 int success = 0;
409
410 // Clear this at start, as we use its non-NULLness later (in the
411 // error path) to decide if we have to free up any memory we
412 // allocated in the process (before failing).
413 *res = NULL;
414
415 // Bogus things we can't serialize. Don't use the proxy. These will fail - let them.
416 if ((hostname != NULL &&
417 strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) ||
418 (servname != NULL &&
419 strcspn(servname, " \n\r\t^'\"") != strlen(servname))) {
420 return EAI_NODATA;
421 }
422
423 FILE* proxy = android_open_proxy();
424 if (proxy == NULL) {
425 return EAI_SYSTEM;
426 }
427
428 netid = __netdClientDispatch.netIdForResolv(netid);
429
430 // Send the request.
431 if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d %u",
432 hostname == NULL ? "^" : hostname,
433 servname == NULL ? "^" : servname,
434 hints == NULL ? -1 : hints->ai_flags,
435 hints == NULL ? -1 : hints->ai_family,
436 hints == NULL ? -1 : hints->ai_socktype,
437 hints == NULL ? -1 : hints->ai_protocol,
438 netid) < 0) {
439 goto exit;
440 }
441 // literal NULL byte at end, required by FrameworkListener
442 if (fputc(0, proxy) == EOF ||
443 fflush(proxy) != 0) {
444 goto exit;
445 }
446
447 char buf[4];
448 // read result code for gethostbyaddr
449 if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) {
450 goto exit;
451 }
452
453 int result_code = (int)strtol(buf, NULL, 10);
454 // verify the code itself
455 if (result_code != DnsProxyQueryResult) {
456 fread(buf, 1, sizeof(buf), proxy);
457 goto exit;
458 }
459
460 struct addrinfo* ai = NULL;
461 struct addrinfo** nextres = res;
462 while (1) {
463 int32_t have_more;
464 if (!readBE32(proxy, &have_more)) {
465 break;
466 }
467 if (have_more == 0) {
468 success = 1;
469 break;
470 }
471
472 struct addrinfo* ai = calloc(1, sizeof(struct addrinfo) + sizeof(struct sockaddr_storage));
473 if (ai == NULL) {
474 break;
475 }
476 ai->ai_addr = (struct sockaddr*)(ai + 1);
477
478 // struct addrinfo {
479 // int ai_flags; /* AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST */
480 // int ai_family; /* PF_xxx */
481 // int ai_socktype; /* SOCK_xxx */
482 // int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
483 // socklen_t ai_addrlen; /* length of ai_addr */
484 // char *ai_canonname; /* canonical name for hostname */
485 // struct sockaddr *ai_addr; /* binary address */
486 // struct addrinfo *ai_next; /* next structure in linked list */
487 // };
488
489 // Read the struct piece by piece because we might be a 32-bit process
490 // talking to a 64-bit netd.
491 int32_t addr_len;
492 bool success =
493 readBE32(proxy, &ai->ai_flags) &&
494 readBE32(proxy, &ai->ai_family) &&
495 readBE32(proxy, &ai->ai_socktype) &&
496 readBE32(proxy, &ai->ai_protocol) &&
497 readBE32(proxy, &addr_len);
498 if (!success) {
499 break;
500 }
501
502 // Set ai_addrlen and read the ai_addr data.
503 ai->ai_addrlen = addr_len;
504 if (addr_len != 0) {
505 if ((size_t) addr_len > sizeof(struct sockaddr_storage)) {
506 // Bogus; too big.
507 break;
508 }
509 if (fread(ai->ai_addr, addr_len, 1, proxy) != 1) {
510 break;
511 }
512 }
513
514 // The string for ai_cannonname.
515 int32_t name_len;
516 if (!readBE32(proxy, &name_len)) {
517 break;
518 }
519 if (name_len != 0) {
520 ai->ai_canonname = (char*) malloc(name_len);
521 if (fread(ai->ai_canonname, name_len, 1, proxy) != 1) {
522 break;
523 }
524 if (ai->ai_canonname[name_len - 1] != '\0') {
525 // The proxy should be returning this
526 // NULL-terminated.
527 break;
528 }
529 }
530
531 *nextres = ai;
532 nextres = &ai->ai_next;
533 ai = NULL;
534 }
535
536 if (ai != NULL) {
537 // Clean up partially-built addrinfo that we never ended up
538 // attaching to the response.
539 freeaddrinfo(ai);
540 }
541 exit:
542 if (proxy != NULL) {
543 fclose(proxy);
544 }
545
546 if (success) {
547 return 0;
548 }
549
550 // Proxy failed;
551 // clean up memory we might've allocated.
552 if (*res) {
553 freeaddrinfo(*res);
554 *res = NULL;
555 }
556 return EAI_NODATA;
557 }
558
559 int
getaddrinfo(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res)560 getaddrinfo(const char *hostname, const char *servname,
561 const struct addrinfo *hints, struct addrinfo **res)
562 {
563 return android_getaddrinfofornet(hostname, servname, hints, NETID_UNSET, MARK_UNSET, res);
564 }
565
566 int
android_getaddrinfofornet(const char * hostname,const char * servname,const struct addrinfo * hints,unsigned netid,unsigned mark,struct addrinfo ** res)567 android_getaddrinfofornet(const char *hostname, const char *servname,
568 const struct addrinfo *hints, unsigned netid, unsigned mark, struct addrinfo **res)
569 {
570 struct android_net_context netcontext = {
571 .app_netid = netid,
572 .app_mark = mark,
573 .dns_netid = netid,
574 .dns_mark = mark,
575 .uid = NET_CONTEXT_INVALID_UID,
576 };
577 return android_getaddrinfofornetcontext(hostname, servname, hints, &netcontext, res);
578 }
579
580 int
android_getaddrinfofornetcontext(const char * hostname,const char * servname,const struct addrinfo * hints,const struct android_net_context * netcontext,struct addrinfo ** res)581 android_getaddrinfofornetcontext(const char *hostname, const char *servname,
582 const struct addrinfo *hints, const struct android_net_context *netcontext,
583 struct addrinfo **res)
584 {
585 struct addrinfo sentinel;
586 struct addrinfo *cur;
587 int error = 0;
588 struct addrinfo ai;
589 struct addrinfo ai0;
590 struct addrinfo *pai;
591 const struct explore *ex;
592
593 /* hostname is allowed to be NULL */
594 /* servname is allowed to be NULL */
595 /* hints is allowed to be NULL */
596 assert(res != NULL);
597 assert(netcontext != NULL);
598 memset(&sentinel, 0, sizeof(sentinel));
599 cur = &sentinel;
600 pai = &ai;
601 pai->ai_flags = 0;
602 pai->ai_family = PF_UNSPEC;
603 pai->ai_socktype = ANY;
604 pai->ai_protocol = ANY;
605 pai->ai_addrlen = 0;
606 pai->ai_canonname = NULL;
607 pai->ai_addr = NULL;
608 pai->ai_next = NULL;
609
610 if (hostname == NULL && servname == NULL)
611 return EAI_NONAME;
612 if (hints) {
613 /* error check for hints */
614 if (hints->ai_addrlen || hints->ai_canonname ||
615 hints->ai_addr || hints->ai_next)
616 ERR(EAI_BADHINTS); /* xxx */
617 if (hints->ai_flags & ~AI_MASK)
618 ERR(EAI_BADFLAGS);
619 switch (hints->ai_family) {
620 case PF_UNSPEC:
621 case PF_INET:
622 #ifdef INET6
623 case PF_INET6:
624 #endif
625 break;
626 default:
627 ERR(EAI_FAMILY);
628 }
629 memcpy(pai, hints, sizeof(*pai));
630
631 /*
632 * if both socktype/protocol are specified, check if they
633 * are meaningful combination.
634 */
635 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
636 for (ex = explore; ex->e_af >= 0; ex++) {
637 if (pai->ai_family != ex->e_af)
638 continue;
639 if (ex->e_socktype == ANY)
640 continue;
641 if (ex->e_protocol == ANY)
642 continue;
643 if (pai->ai_socktype == ex->e_socktype
644 && pai->ai_protocol != ex->e_protocol) {
645 ERR(EAI_BADHINTS);
646 }
647 }
648 }
649 }
650
651 /*
652 * check for special cases. (1) numeric servname is disallowed if
653 * socktype/protocol are left unspecified. (2) servname is disallowed
654 * for raw and other inet{,6} sockets.
655 */
656 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
657 #ifdef PF_INET6
658 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
659 #endif
660 ) {
661 ai0 = *pai; /* backup *pai */
662
663 if (pai->ai_family == PF_UNSPEC) {
664 #ifdef PF_INET6
665 pai->ai_family = PF_INET6;
666 #else
667 pai->ai_family = PF_INET;
668 #endif
669 }
670 error = get_portmatch(pai, servname);
671 if (error)
672 ERR(error);
673
674 *pai = ai0;
675 }
676
677 ai0 = *pai;
678
679 /* NULL hostname, or numeric hostname */
680 for (ex = explore; ex->e_af >= 0; ex++) {
681 *pai = ai0;
682
683 /* PF_UNSPEC entries are prepared for DNS queries only */
684 if (ex->e_af == PF_UNSPEC)
685 continue;
686
687 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
688 continue;
689 if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
690 continue;
691 if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
692 continue;
693
694 if (pai->ai_family == PF_UNSPEC)
695 pai->ai_family = ex->e_af;
696 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
697 pai->ai_socktype = ex->e_socktype;
698 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
699 pai->ai_protocol = ex->e_protocol;
700
701 if (hostname == NULL)
702 error = explore_null(pai, servname, &cur->ai_next);
703 else
704 error = explore_numeric_scope(pai, hostname, servname,
705 &cur->ai_next);
706
707 if (error)
708 goto free;
709
710 while (cur->ai_next)
711 cur = cur->ai_next;
712 }
713
714 /*
715 * XXX
716 * If numeric representation of AF1 can be interpreted as FQDN
717 * representation of AF2, we need to think again about the code below.
718 */
719 if (sentinel.ai_next)
720 goto good;
721
722 if (hostname == NULL)
723 ERR(EAI_NODATA);
724 if (pai->ai_flags & AI_NUMERICHOST)
725 ERR(EAI_NONAME);
726
727 #if defined(__ANDROID__)
728 int gai_error = android_getaddrinfo_proxy(
729 hostname, servname, hints, res, netcontext->app_netid);
730 if (gai_error != EAI_SYSTEM) {
731 return gai_error;
732 }
733 #endif
734
735 /*
736 * hostname as alphabetical name.
737 * we would like to prefer AF_INET6 than AF_INET, so we'll make a
738 * outer loop by AFs.
739 */
740 for (ex = explore; ex->e_af >= 0; ex++) {
741 *pai = ai0;
742
743 /* require exact match for family field */
744 if (pai->ai_family != ex->e_af)
745 continue;
746
747 if (!MATCH(pai->ai_socktype, ex->e_socktype,
748 WILD_SOCKTYPE(ex))) {
749 continue;
750 }
751 if (!MATCH(pai->ai_protocol, ex->e_protocol,
752 WILD_PROTOCOL(ex))) {
753 continue;
754 }
755
756 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
757 pai->ai_socktype = ex->e_socktype;
758 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
759 pai->ai_protocol = ex->e_protocol;
760
761 error = explore_fqdn(
762 pai, hostname, servname, &cur->ai_next, netcontext);
763
764 while (cur && cur->ai_next)
765 cur = cur->ai_next;
766 }
767
768 /* XXX */
769 if (sentinel.ai_next)
770 error = 0;
771
772 if (error)
773 goto free;
774 if (error == 0) {
775 if (sentinel.ai_next) {
776 good:
777 *res = sentinel.ai_next;
778 return SUCCESS;
779 } else
780 error = EAI_FAIL;
781 }
782 free:
783 bad:
784 if (sentinel.ai_next)
785 freeaddrinfo(sentinel.ai_next);
786 *res = NULL;
787 return error;
788 }
789
790 /*
791 * FQDN hostname, DNS lookup
792 */
793 static int
explore_fqdn(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,const struct android_net_context * netcontext)794 explore_fqdn(const struct addrinfo *pai, const char *hostname,
795 const char *servname, struct addrinfo **res,
796 const struct android_net_context *netcontext)
797 {
798 struct addrinfo *result;
799 struct addrinfo *cur;
800 int error = 0;
801 static const ns_dtab dtab[] = {
802 NS_FILES_CB(_files_getaddrinfo, NULL)
803 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
804 NS_NIS_CB(_yp_getaddrinfo, NULL)
805 { 0, 0, 0 }
806 };
807
808 assert(pai != NULL);
809 /* hostname may be NULL */
810 /* servname may be NULL */
811 assert(res != NULL);
812
813 result = NULL;
814
815 /*
816 * if the servname does not match socktype/protocol, ignore it.
817 */
818 if (get_portmatch(pai, servname) != 0)
819 return 0;
820
821 switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
822 default_dns_files, hostname, pai, netcontext)) {
823 case NS_TRYAGAIN:
824 error = EAI_AGAIN;
825 goto free;
826 case NS_UNAVAIL:
827 error = EAI_FAIL;
828 goto free;
829 case NS_NOTFOUND:
830 error = EAI_NODATA;
831 goto free;
832 case NS_SUCCESS:
833 error = 0;
834 for (cur = result; cur; cur = cur->ai_next) {
835 GET_PORT(cur, servname);
836 /* canonname should be filled already */
837 }
838 break;
839 }
840
841 *res = result;
842
843 return 0;
844
845 free:
846 if (result)
847 freeaddrinfo(result);
848 return error;
849 }
850
851 /*
852 * hostname == NULL.
853 * passive socket -> anyaddr (0.0.0.0 or ::)
854 * non-passive socket -> localhost (127.0.0.1 or ::1)
855 */
856 static int
explore_null(const struct addrinfo * pai,const char * servname,struct addrinfo ** res)857 explore_null(const struct addrinfo *pai, const char *servname,
858 struct addrinfo **res)
859 {
860 int s;
861 const struct afd *afd;
862 struct addrinfo *cur;
863 struct addrinfo sentinel;
864 int error;
865
866 assert(pai != NULL);
867 /* servname may be NULL */
868 assert(res != NULL);
869
870 *res = NULL;
871 sentinel.ai_next = NULL;
872 cur = &sentinel;
873
874 /*
875 * filter out AFs that are not supported by the kernel
876 * XXX errno?
877 */
878 s = socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
879 if (s < 0) {
880 if (errno != EMFILE)
881 return 0;
882 } else
883 close(s);
884
885 /*
886 * if the servname does not match socktype/protocol, ignore it.
887 */
888 if (get_portmatch(pai, servname) != 0)
889 return 0;
890
891 afd = find_afd(pai->ai_family);
892 if (afd == NULL)
893 return 0;
894
895 if (pai->ai_flags & AI_PASSIVE) {
896 GET_AI(cur->ai_next, afd, afd->a_addrany);
897 /* xxx meaningless?
898 * GET_CANONNAME(cur->ai_next, "anyaddr");
899 */
900 GET_PORT(cur->ai_next, servname);
901 } else {
902 GET_AI(cur->ai_next, afd, afd->a_loopback);
903 /* xxx meaningless?
904 * GET_CANONNAME(cur->ai_next, "localhost");
905 */
906 GET_PORT(cur->ai_next, servname);
907 }
908 cur = cur->ai_next;
909
910 *res = sentinel.ai_next;
911 return 0;
912
913 free:
914 if (sentinel.ai_next)
915 freeaddrinfo(sentinel.ai_next);
916 return error;
917 }
918
919 /*
920 * numeric hostname
921 */
922 static int
explore_numeric(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,const char * canonname)923 explore_numeric(const struct addrinfo *pai, const char *hostname,
924 const char *servname, struct addrinfo **res, const char *canonname)
925 {
926 const struct afd *afd;
927 struct addrinfo *cur;
928 struct addrinfo sentinel;
929 int error;
930 char pton[PTON_MAX];
931
932 assert(pai != NULL);
933 /* hostname may be NULL */
934 /* servname may be NULL */
935 assert(res != NULL);
936
937 *res = NULL;
938 sentinel.ai_next = NULL;
939 cur = &sentinel;
940
941 /*
942 * if the servname does not match socktype/protocol, ignore it.
943 */
944 if (get_portmatch(pai, servname) != 0)
945 return 0;
946
947 afd = find_afd(pai->ai_family);
948 if (afd == NULL)
949 return 0;
950
951 switch (afd->a_af) {
952 #if 0 /*X/Open spec*/
953 case AF_INET:
954 if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
955 if (pai->ai_family == afd->a_af ||
956 pai->ai_family == PF_UNSPEC /*?*/) {
957 GET_AI(cur->ai_next, afd, pton);
958 GET_PORT(cur->ai_next, servname);
959 if ((pai->ai_flags & AI_CANONNAME)) {
960 /*
961 * Set the numeric address itself as
962 * the canonical name, based on a
963 * clarification in rfc2553bis-03.
964 */
965 GET_CANONNAME(cur->ai_next, canonname);
966 }
967 while (cur && cur->ai_next)
968 cur = cur->ai_next;
969 } else
970 ERR(EAI_FAMILY); /*xxx*/
971 }
972 break;
973 #endif
974 default:
975 if (inet_pton(afd->a_af, hostname, pton) == 1) {
976 if (pai->ai_family == afd->a_af ||
977 pai->ai_family == PF_UNSPEC /*?*/) {
978 GET_AI(cur->ai_next, afd, pton);
979 GET_PORT(cur->ai_next, servname);
980 if ((pai->ai_flags & AI_CANONNAME)) {
981 /*
982 * Set the numeric address itself as
983 * the canonical name, based on a
984 * clarification in rfc2553bis-03.
985 */
986 GET_CANONNAME(cur->ai_next, canonname);
987 }
988 while (cur->ai_next)
989 cur = cur->ai_next;
990 } else
991 ERR(EAI_FAMILY); /*xxx*/
992 }
993 break;
994 }
995
996 *res = sentinel.ai_next;
997 return 0;
998
999 free:
1000 bad:
1001 if (sentinel.ai_next)
1002 freeaddrinfo(sentinel.ai_next);
1003 return error;
1004 }
1005
1006 /*
1007 * numeric hostname with scope
1008 */
1009 static int
explore_numeric_scope(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res)1010 explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
1011 const char *servname, struct addrinfo **res)
1012 {
1013 #if !defined(SCOPE_DELIMITER) || !defined(INET6)
1014 return explore_numeric(pai, hostname, servname, res, hostname);
1015 #else
1016 const struct afd *afd;
1017 struct addrinfo *cur;
1018 int error;
1019 char *cp, *hostname2 = NULL, *scope, *addr;
1020 struct sockaddr_in6 *sin6;
1021
1022 assert(pai != NULL);
1023 /* hostname may be NULL */
1024 /* servname may be NULL */
1025 assert(res != NULL);
1026
1027 /*
1028 * if the servname does not match socktype/protocol, ignore it.
1029 */
1030 if (get_portmatch(pai, servname) != 0)
1031 return 0;
1032
1033 afd = find_afd(pai->ai_family);
1034 if (afd == NULL)
1035 return 0;
1036
1037 if (!afd->a_scoped)
1038 return explore_numeric(pai, hostname, servname, res, hostname);
1039
1040 cp = strchr(hostname, SCOPE_DELIMITER);
1041 if (cp == NULL)
1042 return explore_numeric(pai, hostname, servname, res, hostname);
1043
1044 /*
1045 * Handle special case of <scoped_address><delimiter><scope id>
1046 */
1047 hostname2 = strdup(hostname);
1048 if (hostname2 == NULL)
1049 return EAI_MEMORY;
1050 /* terminate at the delimiter */
1051 hostname2[cp - hostname] = '\0';
1052 addr = hostname2;
1053 scope = cp + 1;
1054
1055 error = explore_numeric(pai, addr, servname, res, hostname);
1056 if (error == 0) {
1057 u_int32_t scopeid;
1058
1059 for (cur = *res; cur; cur = cur->ai_next) {
1060 if (cur->ai_family != AF_INET6)
1061 continue;
1062 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
1063 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
1064 free(hostname2);
1065 return(EAI_NODATA); /* XXX: is return OK? */
1066 }
1067 sin6->sin6_scope_id = scopeid;
1068 }
1069 }
1070
1071 free(hostname2);
1072
1073 return error;
1074 #endif
1075 }
1076
1077 static int
get_canonname(const struct addrinfo * pai,struct addrinfo * ai,const char * str)1078 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
1079 {
1080
1081 assert(pai != NULL);
1082 assert(ai != NULL);
1083 assert(str != NULL);
1084
1085 if ((pai->ai_flags & AI_CANONNAME) != 0) {
1086 ai->ai_canonname = strdup(str);
1087 if (ai->ai_canonname == NULL)
1088 return EAI_MEMORY;
1089 }
1090 return 0;
1091 }
1092
1093 static struct addrinfo *
get_ai(const struct addrinfo * pai,const struct afd * afd,const char * addr)1094 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
1095 {
1096 char *p;
1097 struct addrinfo *ai;
1098
1099 assert(pai != NULL);
1100 assert(afd != NULL);
1101 assert(addr != NULL);
1102
1103 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
1104 + (afd->a_socklen));
1105 if (ai == NULL)
1106 return NULL;
1107
1108 memcpy(ai, pai, sizeof(struct addrinfo));
1109 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1110 memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1111
1112 #ifdef HAVE_SA_LEN
1113 ai->ai_addr->sa_len = afd->a_socklen;
1114 #endif
1115
1116 ai->ai_addrlen = afd->a_socklen;
1117 #if defined (__alpha__) || (defined(__i386__) && defined(_LP64)) || defined(__sparc64__)
1118 ai->__ai_pad0 = 0;
1119 #endif
1120 ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1121 p = (char *)(void *)(ai->ai_addr);
1122 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
1123 return ai;
1124 }
1125
1126 static int
get_portmatch(const struct addrinfo * ai,const char * servname)1127 get_portmatch(const struct addrinfo *ai, const char *servname)
1128 {
1129
1130 assert(ai != NULL);
1131 /* servname may be NULL */
1132
1133 return get_port(ai, servname, 1);
1134 }
1135
1136 static int
get_port(const struct addrinfo * ai,const char * servname,int matchonly)1137 get_port(const struct addrinfo *ai, const char *servname, int matchonly)
1138 {
1139 const char *proto;
1140 struct servent *sp;
1141 int port;
1142 int allownumeric;
1143
1144 assert(ai != NULL);
1145 /* servname may be NULL */
1146
1147 if (servname == NULL)
1148 return 0;
1149 switch (ai->ai_family) {
1150 case AF_INET:
1151 #ifdef AF_INET6
1152 case AF_INET6:
1153 #endif
1154 break;
1155 default:
1156 return 0;
1157 }
1158
1159 switch (ai->ai_socktype) {
1160 case SOCK_RAW:
1161 return EAI_SERVICE;
1162 case SOCK_DGRAM:
1163 case SOCK_STREAM:
1164 allownumeric = 1;
1165 break;
1166 case ANY:
1167 #if 1 /* ANDROID-SPECIFIC CHANGE TO MATCH GLIBC */
1168 allownumeric = 1;
1169 #else
1170 allownumeric = 0;
1171 #endif
1172 break;
1173 default:
1174 return EAI_SOCKTYPE;
1175 }
1176
1177 port = str2number(servname);
1178 if (port >= 0) {
1179 if (!allownumeric)
1180 return EAI_SERVICE;
1181 if (port < 0 || port > 65535)
1182 return EAI_SERVICE;
1183 port = htons(port);
1184 } else {
1185 if (ai->ai_flags & AI_NUMERICSERV)
1186 return EAI_NONAME;
1187
1188 switch (ai->ai_socktype) {
1189 case SOCK_DGRAM:
1190 proto = "udp";
1191 break;
1192 case SOCK_STREAM:
1193 proto = "tcp";
1194 break;
1195 default:
1196 proto = NULL;
1197 break;
1198 }
1199
1200 if ((sp = getservbyname(servname, proto)) == NULL)
1201 return EAI_SERVICE;
1202 port = sp->s_port;
1203 }
1204
1205 if (!matchonly) {
1206 switch (ai->ai_family) {
1207 case AF_INET:
1208 ((struct sockaddr_in *)(void *)
1209 ai->ai_addr)->sin_port = port;
1210 break;
1211 #ifdef INET6
1212 case AF_INET6:
1213 ((struct sockaddr_in6 *)(void *)
1214 ai->ai_addr)->sin6_port = port;
1215 break;
1216 #endif
1217 }
1218 }
1219
1220 return 0;
1221 }
1222
1223 static const struct afd *
find_afd(int af)1224 find_afd(int af)
1225 {
1226 const struct afd *afd;
1227
1228 if (af == PF_UNSPEC)
1229 return NULL;
1230 for (afd = afdl; afd->a_af; afd++) {
1231 if (afd->a_af == af)
1232 return afd;
1233 }
1234 return NULL;
1235 }
1236
1237 #ifdef INET6
1238 /* convert a string to a scope identifier. XXX: IPv6 specific */
1239 static int
ip6_str2scopeid(char * scope,struct sockaddr_in6 * sin6,u_int32_t * scopeid)1240 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
1241 {
1242 u_long lscopeid;
1243 struct in6_addr *a6;
1244 char *ep;
1245
1246 assert(scope != NULL);
1247 assert(sin6 != NULL);
1248 assert(scopeid != NULL);
1249
1250 a6 = &sin6->sin6_addr;
1251
1252 /* empty scopeid portion is invalid */
1253 if (*scope == '\0')
1254 return -1;
1255
1256 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
1257 /*
1258 * We currently assume a one-to-one mapping between links
1259 * and interfaces, so we simply use interface indices for
1260 * like-local scopes.
1261 */
1262 *scopeid = if_nametoindex(scope);
1263 if (*scopeid == 0)
1264 goto trynumeric;
1265 return 0;
1266 }
1267
1268 /* still unclear about literal, allow numeric only - placeholder */
1269 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1270 goto trynumeric;
1271 if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1272 goto trynumeric;
1273 else
1274 goto trynumeric; /* global */
1275
1276 /* try to convert to a numeric id as a last resort */
1277 trynumeric:
1278 errno = 0;
1279 lscopeid = strtoul(scope, &ep, 10);
1280 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
1281 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
1282 return 0;
1283 else
1284 return -1;
1285 }
1286 #endif
1287
1288 /* code duplicate with gethnamaddr.c */
1289
1290 static const char AskedForGot[] =
1291 "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1292
1293 static struct addrinfo *
getanswer(const querybuf * answer,int anslen,const char * qname,int qtype,const struct addrinfo * pai)1294 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
1295 const struct addrinfo *pai)
1296 {
1297 struct addrinfo sentinel, *cur;
1298 struct addrinfo ai;
1299 const struct afd *afd;
1300 char *canonname;
1301 const HEADER *hp;
1302 const u_char *cp;
1303 int n;
1304 const u_char *eom;
1305 char *bp, *ep;
1306 int type, class, ancount, qdcount;
1307 int haveanswer, had_error;
1308 char tbuf[MAXDNAME];
1309 int (*name_ok) (const char *);
1310 char hostbuf[8*1024];
1311
1312 assert(answer != NULL);
1313 assert(qname != NULL);
1314 assert(pai != NULL);
1315
1316 memset(&sentinel, 0, sizeof(sentinel));
1317 cur = &sentinel;
1318
1319 canonname = NULL;
1320 eom = answer->buf + anslen;
1321 switch (qtype) {
1322 case T_A:
1323 case T_AAAA:
1324 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
1325 name_ok = res_hnok;
1326 break;
1327 default:
1328 return NULL; /* XXX should be abort(); */
1329 }
1330 /*
1331 * find first satisfactory answer
1332 */
1333 hp = &answer->hdr;
1334 ancount = ntohs(hp->ancount);
1335 qdcount = ntohs(hp->qdcount);
1336 bp = hostbuf;
1337 ep = hostbuf + sizeof hostbuf;
1338 cp = answer->buf + HFIXEDSZ;
1339 if (qdcount != 1) {
1340 h_errno = NO_RECOVERY;
1341 return (NULL);
1342 }
1343 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
1344 if ((n < 0) || !(*name_ok)(bp)) {
1345 h_errno = NO_RECOVERY;
1346 return (NULL);
1347 }
1348 cp += n + QFIXEDSZ;
1349 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
1350 /* res_send() has already verified that the query name is the
1351 * same as the one we sent; this just gets the expanded name
1352 * (i.e., with the succeeding search-domain tacked on).
1353 */
1354 n = strlen(bp) + 1; /* for the \0 */
1355 if (n >= MAXHOSTNAMELEN) {
1356 h_errno = NO_RECOVERY;
1357 return (NULL);
1358 }
1359 canonname = bp;
1360 bp += n;
1361 /* The qname can be abbreviated, but h_name is now absolute. */
1362 qname = canonname;
1363 }
1364 haveanswer = 0;
1365 had_error = 0;
1366 while (ancount-- > 0 && cp < eom && !had_error) {
1367 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
1368 if ((n < 0) || !(*name_ok)(bp)) {
1369 had_error++;
1370 continue;
1371 }
1372 cp += n; /* name */
1373 type = _getshort(cp);
1374 cp += INT16SZ; /* type */
1375 class = _getshort(cp);
1376 cp += INT16SZ + INT32SZ; /* class, TTL */
1377 n = _getshort(cp);
1378 cp += INT16SZ; /* len */
1379 if (class != C_IN) {
1380 /* XXX - debug? syslog? */
1381 cp += n;
1382 continue; /* XXX - had_error++ ? */
1383 }
1384 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
1385 type == T_CNAME) {
1386 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
1387 if ((n < 0) || !(*name_ok)(tbuf)) {
1388 had_error++;
1389 continue;
1390 }
1391 cp += n;
1392 /* Get canonical name. */
1393 n = strlen(tbuf) + 1; /* for the \0 */
1394 if (n > ep - bp || n >= MAXHOSTNAMELEN) {
1395 had_error++;
1396 continue;
1397 }
1398 strlcpy(bp, tbuf, (size_t)(ep - bp));
1399 canonname = bp;
1400 bp += n;
1401 continue;
1402 }
1403 if (qtype == T_ANY) {
1404 if (!(type == T_A || type == T_AAAA)) {
1405 cp += n;
1406 continue;
1407 }
1408 } else if (type != qtype) {
1409 if (type != T_KEY && type != T_SIG)
1410 syslog(LOG_NOTICE|LOG_AUTH,
1411 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
1412 qname, p_class(C_IN), p_type(qtype),
1413 p_type(type));
1414 cp += n;
1415 continue; /* XXX - had_error++ ? */
1416 }
1417 switch (type) {
1418 case T_A:
1419 case T_AAAA:
1420 if (strcasecmp(canonname, bp) != 0) {
1421 syslog(LOG_NOTICE|LOG_AUTH,
1422 AskedForGot, canonname, bp);
1423 cp += n;
1424 continue; /* XXX - had_error++ ? */
1425 }
1426 if (type == T_A && n != INADDRSZ) {
1427 cp += n;
1428 continue;
1429 }
1430 if (type == T_AAAA && n != IN6ADDRSZ) {
1431 cp += n;
1432 continue;
1433 }
1434 if (type == T_AAAA) {
1435 struct in6_addr in6;
1436 memcpy(&in6, cp, IN6ADDRSZ);
1437 if (IN6_IS_ADDR_V4MAPPED(&in6)) {
1438 cp += n;
1439 continue;
1440 }
1441 }
1442 if (!haveanswer) {
1443 int nn;
1444
1445 canonname = bp;
1446 nn = strlen(bp) + 1; /* for the \0 */
1447 bp += nn;
1448 }
1449
1450 /* don't overwrite pai */
1451 ai = *pai;
1452 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
1453 afd = find_afd(ai.ai_family);
1454 if (afd == NULL) {
1455 cp += n;
1456 continue;
1457 }
1458 cur->ai_next = get_ai(&ai, afd, (const char *)cp);
1459 if (cur->ai_next == NULL)
1460 had_error++;
1461 while (cur && cur->ai_next)
1462 cur = cur->ai_next;
1463 cp += n;
1464 break;
1465 default:
1466 abort();
1467 }
1468 if (!had_error)
1469 haveanswer++;
1470 }
1471 if (haveanswer) {
1472 if (!canonname)
1473 (void)get_canonname(pai, sentinel.ai_next, qname);
1474 else
1475 (void)get_canonname(pai, sentinel.ai_next, canonname);
1476 h_errno = NETDB_SUCCESS;
1477 return sentinel.ai_next;
1478 }
1479
1480 h_errno = NO_RECOVERY;
1481 return NULL;
1482 }
1483
1484 struct addrinfo_sort_elem {
1485 struct addrinfo *ai;
1486 int has_src_addr;
1487 sockaddr_union src_addr;
1488 int original_order;
1489 };
1490
1491 /*ARGSUSED*/
1492 static int
_get_scope(const struct sockaddr * addr)1493 _get_scope(const struct sockaddr *addr)
1494 {
1495 if (addr->sa_family == AF_INET6) {
1496 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1497 if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) {
1498 return IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr);
1499 } else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) ||
1500 IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) {
1501 /*
1502 * RFC 4291 section 2.5.3 says loopback is to be treated as having
1503 * link-local scope.
1504 */
1505 return IPV6_ADDR_SCOPE_LINKLOCAL;
1506 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
1507 return IPV6_ADDR_SCOPE_SITELOCAL;
1508 } else {
1509 return IPV6_ADDR_SCOPE_GLOBAL;
1510 }
1511 } else if (addr->sa_family == AF_INET) {
1512 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
1513 unsigned long int na = ntohl(addr4->sin_addr.s_addr);
1514
1515 if (IN_LOOPBACK(na) || /* 127.0.0.0/8 */
1516 (na & 0xffff0000) == 0xa9fe0000) { /* 169.254.0.0/16 */
1517 return IPV6_ADDR_SCOPE_LINKLOCAL;
1518 } else {
1519 /*
1520 * RFC 6724 section 3.2. Other IPv4 addresses, including private addresses
1521 * and shared addresses (100.64.0.0/10), are assigned global scope.
1522 */
1523 return IPV6_ADDR_SCOPE_GLOBAL;
1524 }
1525 } else {
1526 /*
1527 * This should never happen.
1528 * Return a scope with low priority as a last resort.
1529 */
1530 return IPV6_ADDR_SCOPE_NODELOCAL;
1531 }
1532 }
1533
1534 /* These macros are modelled after the ones in <netinet/in6.h>. */
1535
1536 /* RFC 4380, section 2.6 */
1537 #define IN6_IS_ADDR_TEREDO(a) \
1538 ((*(const uint32_t *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000)))
1539
1540 /* RFC 3056, section 2. */
1541 #define IN6_IS_ADDR_6TO4(a) \
1542 (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02))
1543
1544 /* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */
1545 #define IN6_IS_ADDR_6BONE(a) \
1546 (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe))
1547
1548 /*
1549 * Get the label for a given IPv4/IPv6 address.
1550 * RFC 6724, section 2.1.
1551 */
1552
1553 /*ARGSUSED*/
1554 static int
_get_label(const struct sockaddr * addr)1555 _get_label(const struct sockaddr *addr)
1556 {
1557 if (addr->sa_family == AF_INET) {
1558 return 4;
1559 } else if (addr->sa_family == AF_INET6) {
1560 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *) addr;
1561 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
1562 return 0;
1563 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
1564 return 4;
1565 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
1566 return 2;
1567 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
1568 return 5;
1569 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
1570 return 13;
1571 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) {
1572 return 3;
1573 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
1574 return 11;
1575 } else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
1576 return 12;
1577 } else {
1578 /* All other IPv6 addresses, including global unicast addresses. */
1579 return 1;
1580 }
1581 } else {
1582 /*
1583 * This should never happen.
1584 * Return a semi-random label as a last resort.
1585 */
1586 return 1;
1587 }
1588 }
1589
1590 /*
1591 * Get the precedence for a given IPv4/IPv6 address.
1592 * RFC 6724, section 2.1.
1593 */
1594
1595 /*ARGSUSED*/
1596 static int
_get_precedence(const struct sockaddr * addr)1597 _get_precedence(const struct sockaddr *addr)
1598 {
1599 if (addr->sa_family == AF_INET) {
1600 return 35;
1601 } else if (addr->sa_family == AF_INET6) {
1602 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1603 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
1604 return 50;
1605 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
1606 return 35;
1607 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
1608 return 30;
1609 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
1610 return 5;
1611 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
1612 return 3;
1613 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) ||
1614 IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) ||
1615 IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
1616 return 1;
1617 } else {
1618 /* All other IPv6 addresses, including global unicast addresses. */
1619 return 40;
1620 }
1621 } else {
1622 return 1;
1623 }
1624 }
1625
1626 /*
1627 * Find number of matching initial bits between the two addresses a1 and a2.
1628 */
1629
1630 /*ARGSUSED*/
1631 static int
_common_prefix_len(const struct in6_addr * a1,const struct in6_addr * a2)1632 _common_prefix_len(const struct in6_addr *a1, const struct in6_addr *a2)
1633 {
1634 const char *p1 = (const char *)a1;
1635 const char *p2 = (const char *)a2;
1636 unsigned i;
1637
1638 for (i = 0; i < sizeof(*a1); ++i) {
1639 int x, j;
1640
1641 if (p1[i] == p2[i]) {
1642 continue;
1643 }
1644 x = p1[i] ^ p2[i];
1645 for (j = 0; j < CHAR_BIT; ++j) {
1646 if (x & (1 << (CHAR_BIT - 1))) {
1647 return i * CHAR_BIT + j;
1648 }
1649 x <<= 1;
1650 }
1651 }
1652 return sizeof(*a1) * CHAR_BIT;
1653 }
1654
1655 /*
1656 * Compare two source/destination address pairs.
1657 * RFC 6724, section 6.
1658 */
1659
1660 /*ARGSUSED*/
1661 static int
_rfc6724_compare(const void * ptr1,const void * ptr2)1662 _rfc6724_compare(const void *ptr1, const void* ptr2)
1663 {
1664 const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1;
1665 const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2;
1666 int scope_src1, scope_dst1, scope_match1;
1667 int scope_src2, scope_dst2, scope_match2;
1668 int label_src1, label_dst1, label_match1;
1669 int label_src2, label_dst2, label_match2;
1670 int precedence1, precedence2;
1671 int prefixlen1, prefixlen2;
1672
1673 /* Rule 1: Avoid unusable destinations. */
1674 if (a1->has_src_addr != a2->has_src_addr) {
1675 return a2->has_src_addr - a1->has_src_addr;
1676 }
1677
1678 /* Rule 2: Prefer matching scope. */
1679 scope_src1 = _get_scope(&a1->src_addr.generic);
1680 scope_dst1 = _get_scope(a1->ai->ai_addr);
1681 scope_match1 = (scope_src1 == scope_dst1);
1682
1683 scope_src2 = _get_scope(&a2->src_addr.generic);
1684 scope_dst2 = _get_scope(a2->ai->ai_addr);
1685 scope_match2 = (scope_src2 == scope_dst2);
1686
1687 if (scope_match1 != scope_match2) {
1688 return scope_match2 - scope_match1;
1689 }
1690
1691 /*
1692 * Rule 3: Avoid deprecated addresses.
1693 * TODO(sesse): We don't currently have a good way of finding this.
1694 */
1695
1696 /*
1697 * Rule 4: Prefer home addresses.
1698 * TODO(sesse): We don't currently have a good way of finding this.
1699 */
1700
1701 /* Rule 5: Prefer matching label. */
1702 label_src1 = _get_label(&a1->src_addr.generic);
1703 label_dst1 = _get_label(a1->ai->ai_addr);
1704 label_match1 = (label_src1 == label_dst1);
1705
1706 label_src2 = _get_label(&a2->src_addr.generic);
1707 label_dst2 = _get_label(a2->ai->ai_addr);
1708 label_match2 = (label_src2 == label_dst2);
1709
1710 if (label_match1 != label_match2) {
1711 return label_match2 - label_match1;
1712 }
1713
1714 /* Rule 6: Prefer higher precedence. */
1715 precedence1 = _get_precedence(a1->ai->ai_addr);
1716 precedence2 = _get_precedence(a2->ai->ai_addr);
1717 if (precedence1 != precedence2) {
1718 return precedence2 - precedence1;
1719 }
1720
1721 /*
1722 * Rule 7: Prefer native transport.
1723 * TODO(sesse): We don't currently have a good way of finding this.
1724 */
1725
1726 /* Rule 8: Prefer smaller scope. */
1727 if (scope_dst1 != scope_dst2) {
1728 return scope_dst1 - scope_dst2;
1729 }
1730
1731 /*
1732 * Rule 9: Use longest matching prefix.
1733 * We implement this for IPv6 only, as the rules in RFC 6724 don't seem
1734 * to work very well directly applied to IPv4. (glibc uses information from
1735 * the routing table for a custom IPv4 implementation here.)
1736 */
1737 if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 &&
1738 a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6) {
1739 const struct sockaddr_in6 *a1_src = &a1->src_addr.in6;
1740 const struct sockaddr_in6 *a1_dst = (const struct sockaddr_in6 *)a1->ai->ai_addr;
1741 const struct sockaddr_in6 *a2_src = &a2->src_addr.in6;
1742 const struct sockaddr_in6 *a2_dst = (const struct sockaddr_in6 *)a2->ai->ai_addr;
1743 prefixlen1 = _common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr);
1744 prefixlen2 = _common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr);
1745 if (prefixlen1 != prefixlen2) {
1746 return prefixlen2 - prefixlen1;
1747 }
1748 }
1749
1750 /*
1751 * Rule 10: Leave the order unchanged.
1752 * We need this since qsort() is not necessarily stable.
1753 */
1754 return a1->original_order - a2->original_order;
1755 }
1756
1757 /*
1758 * Find the source address that will be used if trying to connect to the given
1759 * address. src_addr must be large enough to hold a struct sockaddr_in6.
1760 *
1761 * Returns 1 if a source address was found, 0 if the address is unreachable,
1762 * and -1 if a fatal error occurred. If 0 or -1, the contents of src_addr are
1763 * undefined.
1764 */
1765
1766 /*ARGSUSED*/
1767 static int
_find_src_addr(const struct sockaddr * addr,struct sockaddr * src_addr,unsigned mark,uid_t uid)1768 _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned mark, uid_t uid)
1769 {
1770 int sock;
1771 int ret;
1772 socklen_t len;
1773
1774 switch (addr->sa_family) {
1775 case AF_INET:
1776 len = sizeof(struct sockaddr_in);
1777 break;
1778 case AF_INET6:
1779 len = sizeof(struct sockaddr_in6);
1780 break;
1781 default:
1782 /* No known usable source address for non-INET families. */
1783 return 0;
1784 }
1785
1786 sock = socket(addr->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
1787 if (sock == -1) {
1788 if (errno == EAFNOSUPPORT) {
1789 return 0;
1790 } else {
1791 return -1;
1792 }
1793 }
1794 if (mark != MARK_UNSET && setsockopt(sock, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0)
1795 return 0;
1796 if (uid > 0 && uid != NET_CONTEXT_INVALID_UID && fchown(sock, uid, (gid_t)-1) < 0)
1797 return 0;
1798 do {
1799 ret = __connect(sock, addr, len);
1800 } while (ret == -1 && errno == EINTR);
1801
1802 if (ret == -1) {
1803 close(sock);
1804 return 0;
1805 }
1806
1807 if (src_addr && getsockname(sock, src_addr, &len) == -1) {
1808 close(sock);
1809 return -1;
1810 }
1811 close(sock);
1812 return 1;
1813 }
1814
1815 /*
1816 * Sort the linked list starting at sentinel->ai_next in RFC6724 order.
1817 * Will leave the list unchanged if an error occurs.
1818 */
1819
1820 /*ARGSUSED*/
1821 static void
_rfc6724_sort(struct addrinfo * list_sentinel,unsigned mark,uid_t uid)1822 _rfc6724_sort(struct addrinfo *list_sentinel, unsigned mark, uid_t uid)
1823 {
1824 struct addrinfo *cur;
1825 int nelem = 0, i;
1826 struct addrinfo_sort_elem *elems;
1827
1828 cur = list_sentinel->ai_next;
1829 while (cur) {
1830 ++nelem;
1831 cur = cur->ai_next;
1832 }
1833
1834 elems = (struct addrinfo_sort_elem *)malloc(nelem * sizeof(struct addrinfo_sort_elem));
1835 if (elems == NULL) {
1836 goto error;
1837 }
1838
1839 /*
1840 * Convert the linked list to an array that also contains the candidate
1841 * source address for each destination address.
1842 */
1843 for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) {
1844 int has_src_addr;
1845 assert(cur != NULL);
1846 elems[i].ai = cur;
1847 elems[i].original_order = i;
1848
1849 has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic, mark, uid);
1850 if (has_src_addr == -1) {
1851 goto error;
1852 }
1853 elems[i].has_src_addr = has_src_addr;
1854 }
1855
1856 /* Sort the addresses, and rearrange the linked list so it matches the sorted order. */
1857 qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem), _rfc6724_compare);
1858
1859 list_sentinel->ai_next = elems[0].ai;
1860 for (i = 0; i < nelem - 1; ++i) {
1861 elems[i].ai->ai_next = elems[i + 1].ai;
1862 }
1863 elems[nelem - 1].ai->ai_next = NULL;
1864
1865 error:
1866 free(elems);
1867 }
1868
1869 /*ARGSUSED*/
1870 static int
_dns_getaddrinfo(void * rv,void * cb_data,va_list ap)1871 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
1872 {
1873 struct addrinfo *ai;
1874 querybuf *buf, *buf2;
1875 const char *name;
1876 const struct addrinfo *pai;
1877 struct addrinfo sentinel, *cur;
1878 struct res_target q, q2;
1879 res_state res;
1880 const struct android_net_context *netcontext;
1881
1882 name = va_arg(ap, char *);
1883 pai = va_arg(ap, const struct addrinfo *);
1884 netcontext = va_arg(ap, const struct android_net_context *);
1885 //fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name);
1886
1887 memset(&q, 0, sizeof(q));
1888 memset(&q2, 0, sizeof(q2));
1889 memset(&sentinel, 0, sizeof(sentinel));
1890 cur = &sentinel;
1891
1892 buf = malloc(sizeof(*buf));
1893 if (buf == NULL) {
1894 h_errno = NETDB_INTERNAL;
1895 return NS_NOTFOUND;
1896 }
1897 buf2 = malloc(sizeof(*buf2));
1898 if (buf2 == NULL) {
1899 free(buf);
1900 h_errno = NETDB_INTERNAL;
1901 return NS_NOTFOUND;
1902 }
1903
1904 switch (pai->ai_family) {
1905 case AF_UNSPEC:
1906 /* prefer IPv6 */
1907 q.name = name;
1908 q.qclass = C_IN;
1909 q.answer = buf->buf;
1910 q.anslen = sizeof(buf->buf);
1911 int query_ipv6 = 1, query_ipv4 = 1;
1912 if (pai->ai_flags & AI_ADDRCONFIG) {
1913 query_ipv6 = _have_ipv6(netcontext->app_mark, netcontext->uid);
1914 query_ipv4 = _have_ipv4(netcontext->app_mark, netcontext->uid);
1915 }
1916 if (query_ipv6) {
1917 q.qtype = T_AAAA;
1918 if (query_ipv4) {
1919 q.next = &q2;
1920 q2.name = name;
1921 q2.qclass = C_IN;
1922 q2.qtype = T_A;
1923 q2.answer = buf2->buf;
1924 q2.anslen = sizeof(buf2->buf);
1925 }
1926 } else if (query_ipv4) {
1927 q.qtype = T_A;
1928 } else {
1929 free(buf);
1930 free(buf2);
1931 return NS_NOTFOUND;
1932 }
1933 break;
1934 case AF_INET:
1935 q.name = name;
1936 q.qclass = C_IN;
1937 q.qtype = T_A;
1938 q.answer = buf->buf;
1939 q.anslen = sizeof(buf->buf);
1940 break;
1941 case AF_INET6:
1942 q.name = name;
1943 q.qclass = C_IN;
1944 q.qtype = T_AAAA;
1945 q.answer = buf->buf;
1946 q.anslen = sizeof(buf->buf);
1947 break;
1948 default:
1949 free(buf);
1950 free(buf2);
1951 return NS_UNAVAIL;
1952 }
1953
1954 res = __res_get_state();
1955 if (res == NULL) {
1956 free(buf);
1957 free(buf2);
1958 return NS_NOTFOUND;
1959 }
1960
1961 /* this just sets our netid val in the thread private data so we don't have to
1962 * modify the api's all the way down to res_send.c's res_nsend. We could
1963 * fully populate the thread private data here, but if we get down there
1964 * and have a cache hit that would be wasted, so we do the rest there on miss
1965 */
1966 res_setnetid(res, netcontext->dns_netid);
1967 res_setmark(res, netcontext->dns_mark);
1968 if (res_searchN(name, &q, res) < 0) {
1969 __res_put_state(res);
1970 free(buf);
1971 free(buf2);
1972 return NS_NOTFOUND;
1973 }
1974 ai = getanswer(buf, q.n, q.name, q.qtype, pai);
1975 if (ai) {
1976 cur->ai_next = ai;
1977 while (cur && cur->ai_next)
1978 cur = cur->ai_next;
1979 }
1980 if (q.next) {
1981 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai);
1982 if (ai)
1983 cur->ai_next = ai;
1984 }
1985 free(buf);
1986 free(buf2);
1987 if (sentinel.ai_next == NULL) {
1988 __res_put_state(res);
1989 switch (h_errno) {
1990 case HOST_NOT_FOUND:
1991 return NS_NOTFOUND;
1992 case TRY_AGAIN:
1993 return NS_TRYAGAIN;
1994 default:
1995 return NS_UNAVAIL;
1996 }
1997 }
1998
1999 _rfc6724_sort(&sentinel, netcontext->app_mark, netcontext->uid);
2000
2001 __res_put_state(res);
2002
2003 *((struct addrinfo **)rv) = sentinel.ai_next;
2004 return NS_SUCCESS;
2005 }
2006
2007 static void
_sethtent(FILE ** hostf)2008 _sethtent(FILE **hostf)
2009 {
2010
2011 if (!*hostf)
2012 *hostf = fopen(_PATH_HOSTS, "re");
2013 else
2014 rewind(*hostf);
2015 }
2016
2017 static void
_endhtent(FILE ** hostf)2018 _endhtent(FILE **hostf)
2019 {
2020
2021 if (*hostf) {
2022 (void) fclose(*hostf);
2023 *hostf = NULL;
2024 }
2025 }
2026
2027 static struct addrinfo *
_gethtent(FILE ** hostf,const char * name,const struct addrinfo * pai)2028 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai)
2029 {
2030 char *p;
2031 char *cp, *tname, *cname;
2032 struct addrinfo hints, *res0, *res;
2033 int error;
2034 const char *addr;
2035 char hostbuf[8*1024];
2036
2037 // fprintf(stderr, "_gethtent() name = '%s'\n", name);
2038 assert(name != NULL);
2039 assert(pai != NULL);
2040
2041 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re")))
2042 return (NULL);
2043 again:
2044 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf)))
2045 return (NULL);
2046 if (*p == '#')
2047 goto again;
2048 if (!(cp = strpbrk(p, "#\n")))
2049 goto again;
2050 *cp = '\0';
2051 if (!(cp = strpbrk(p, " \t")))
2052 goto again;
2053 *cp++ = '\0';
2054 addr = p;
2055 /* if this is not something we're looking for, skip it. */
2056 cname = NULL;
2057 while (cp && *cp) {
2058 if (*cp == ' ' || *cp == '\t') {
2059 cp++;
2060 continue;
2061 }
2062 if (!cname)
2063 cname = cp;
2064 tname = cp;
2065 if ((cp = strpbrk(cp, " \t")) != NULL)
2066 *cp++ = '\0';
2067 // fprintf(stderr, "\ttname = '%s'", tname);
2068 if (strcasecmp(name, tname) == 0)
2069 goto found;
2070 }
2071 goto again;
2072
2073 found:
2074 hints = *pai;
2075 hints.ai_flags = AI_NUMERICHOST;
2076 error = getaddrinfo(addr, NULL, &hints, &res0);
2077 if (error)
2078 goto again;
2079 for (res = res0; res; res = res->ai_next) {
2080 /* cover it up */
2081 res->ai_flags = pai->ai_flags;
2082
2083 if (pai->ai_flags & AI_CANONNAME) {
2084 if (get_canonname(pai, res, cname) != 0) {
2085 freeaddrinfo(res0);
2086 goto again;
2087 }
2088 }
2089 }
2090 return res0;
2091 }
2092
2093 /*ARGSUSED*/
2094 static int
_files_getaddrinfo(void * rv,void * cb_data,va_list ap)2095 _files_getaddrinfo(void *rv, void *cb_data, va_list ap)
2096 {
2097 const char *name;
2098 const struct addrinfo *pai;
2099 struct addrinfo sentinel, *cur;
2100 struct addrinfo *p;
2101 FILE *hostf = NULL;
2102
2103 name = va_arg(ap, char *);
2104 pai = va_arg(ap, struct addrinfo *);
2105
2106 // fprintf(stderr, "_files_getaddrinfo() name = '%s'\n", name);
2107 memset(&sentinel, 0, sizeof(sentinel));
2108 cur = &sentinel;
2109
2110 _sethtent(&hostf);
2111 while ((p = _gethtent(&hostf, name, pai)) != NULL) {
2112 cur->ai_next = p;
2113 while (cur && cur->ai_next)
2114 cur = cur->ai_next;
2115 }
2116 _endhtent(&hostf);
2117
2118 *((struct addrinfo **)rv) = sentinel.ai_next;
2119 if (sentinel.ai_next == NULL)
2120 return NS_NOTFOUND;
2121 return NS_SUCCESS;
2122 }
2123
2124 /* resolver logic */
2125
2126 /*
2127 * Formulate a normal query, send, and await answer.
2128 * Returned answer is placed in supplied buffer "answer".
2129 * Perform preliminary check of answer, returning success only
2130 * if no error is indicated and the answer count is nonzero.
2131 * Return the size of the response on success, -1 on error.
2132 * Error number is left in h_errno.
2133 *
2134 * Caller must parse answer and determine whether it answers the question.
2135 */
2136 static int
res_queryN(const char * name,struct res_target * target,res_state res)2137 res_queryN(const char *name, /* domain name */ struct res_target *target,
2138 res_state res)
2139 {
2140 u_char buf[MAXPACKET];
2141 HEADER *hp;
2142 int n;
2143 struct res_target *t;
2144 int rcode;
2145 int ancount;
2146
2147 assert(name != NULL);
2148 /* XXX: target may be NULL??? */
2149
2150 rcode = NOERROR;
2151 ancount = 0;
2152
2153 for (t = target; t; t = t->next) {
2154 int class, type;
2155 u_char *answer;
2156 int anslen;
2157
2158 hp = (HEADER *)(void *)t->answer;
2159 hp->rcode = NOERROR; /* default */
2160
2161 /* make it easier... */
2162 class = t->qclass;
2163 type = t->qtype;
2164 answer = t->answer;
2165 anslen = t->anslen;
2166 #ifdef DEBUG
2167 if (res->options & RES_DEBUG)
2168 printf(";; res_nquery(%s, %d, %d)\n", name, class, type);
2169 #endif
2170
2171 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
2172 buf, sizeof(buf));
2173 #ifdef RES_USE_EDNS0
2174 if (n > 0 && (res->options & RES_USE_EDNS0) != 0)
2175 n = res_nopt(res, n, buf, sizeof(buf), anslen);
2176 #endif
2177 if (n <= 0) {
2178 #ifdef DEBUG
2179 if (res->options & RES_DEBUG)
2180 printf(";; res_nquery: mkquery failed\n");
2181 #endif
2182 h_errno = NO_RECOVERY;
2183 return n;
2184 }
2185 n = res_nsend(res, buf, n, answer, anslen);
2186 #if 0
2187 if (n < 0) {
2188 #ifdef DEBUG
2189 if (res->options & RES_DEBUG)
2190 printf(";; res_query: send error\n");
2191 #endif
2192 h_errno = TRY_AGAIN;
2193 return n;
2194 }
2195 #endif
2196
2197 if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
2198 rcode = hp->rcode; /* record most recent error */
2199 #ifdef DEBUG
2200 if (res->options & RES_DEBUG)
2201 printf(";; rcode = %u, ancount=%u\n", hp->rcode,
2202 ntohs(hp->ancount));
2203 #endif
2204 continue;
2205 }
2206
2207 ancount += ntohs(hp->ancount);
2208
2209 t->n = n;
2210 }
2211
2212 if (ancount == 0) {
2213 switch (rcode) {
2214 case NXDOMAIN:
2215 h_errno = HOST_NOT_FOUND;
2216 break;
2217 case SERVFAIL:
2218 h_errno = TRY_AGAIN;
2219 break;
2220 case NOERROR:
2221 h_errno = NO_DATA;
2222 break;
2223 case FORMERR:
2224 case NOTIMP:
2225 case REFUSED:
2226 default:
2227 h_errno = NO_RECOVERY;
2228 break;
2229 }
2230 return -1;
2231 }
2232 return ancount;
2233 }
2234
2235 /*
2236 * Formulate a normal query, send, and retrieve answer in supplied buffer.
2237 * Return the size of the response on success, -1 on error.
2238 * If enabled, implement search rules until answer or unrecoverable failure
2239 * is detected. Error code, if any, is left in h_errno.
2240 */
2241 static int
res_searchN(const char * name,struct res_target * target,res_state res)2242 res_searchN(const char *name, struct res_target *target, res_state res)
2243 {
2244 const char *cp, * const *domain;
2245 HEADER *hp;
2246 u_int dots;
2247 int trailing_dot, ret, saved_herrno;
2248 int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
2249
2250 assert(name != NULL);
2251 assert(target != NULL);
2252
2253 hp = (HEADER *)(void *)target->answer; /*XXX*/
2254
2255 errno = 0;
2256 h_errno = HOST_NOT_FOUND; /* default, if we never query */
2257 dots = 0;
2258 for (cp = name; *cp; cp++)
2259 dots += (*cp == '.');
2260 trailing_dot = 0;
2261 if (cp > name && *--cp == '.')
2262 trailing_dot++;
2263
2264
2265 //fprintf(stderr, "res_searchN() name = '%s'\n", name);
2266
2267 /*
2268 * if there aren't any dots, it could be a user-level alias
2269 */
2270 if (!dots && (cp = __hostalias(name)) != NULL) {
2271 ret = res_queryN(cp, target, res);
2272 return ret;
2273 }
2274
2275 /*
2276 * If there are dots in the name already, let's just give it a try
2277 * 'as is'. The threshold can be set with the "ndots" option.
2278 */
2279 saved_herrno = -1;
2280 if (dots >= res->ndots) {
2281 ret = res_querydomainN(name, NULL, target, res);
2282 if (ret > 0)
2283 return (ret);
2284 saved_herrno = h_errno;
2285 tried_as_is++;
2286 }
2287
2288 /*
2289 * We do at least one level of search if
2290 * - there is no dot and RES_DEFNAME is set, or
2291 * - there is at least one dot, there is no trailing dot,
2292 * and RES_DNSRCH is set.
2293 */
2294 if ((!dots && (res->options & RES_DEFNAMES)) ||
2295 (dots && !trailing_dot && (res->options & RES_DNSRCH))) {
2296 int done = 0;
2297
2298 /* Unfortunately we need to set stuff up before
2299 * the domain stuff is tried. Will have a better
2300 * fix after thread pools are used.
2301 */
2302 _resolv_populate_res_for_net(res);
2303
2304 for (domain = (const char * const *)res->dnsrch;
2305 *domain && !done;
2306 domain++) {
2307
2308 ret = res_querydomainN(name, *domain, target, res);
2309 if (ret > 0)
2310 return ret;
2311
2312 /*
2313 * If no server present, give up.
2314 * If name isn't found in this domain,
2315 * keep trying higher domains in the search list
2316 * (if that's enabled).
2317 * On a NO_DATA error, keep trying, otherwise
2318 * a wildcard entry of another type could keep us
2319 * from finding this entry higher in the domain.
2320 * If we get some other error (negative answer or
2321 * server failure), then stop searching up,
2322 * but try the input name below in case it's
2323 * fully-qualified.
2324 */
2325 if (errno == ECONNREFUSED) {
2326 h_errno = TRY_AGAIN;
2327 return -1;
2328 }
2329
2330 switch (h_errno) {
2331 case NO_DATA:
2332 got_nodata++;
2333 /* FALLTHROUGH */
2334 case HOST_NOT_FOUND:
2335 /* keep trying */
2336 break;
2337 case TRY_AGAIN:
2338 if (hp->rcode == SERVFAIL) {
2339 /* try next search element, if any */
2340 got_servfail++;
2341 break;
2342 }
2343 /* FALLTHROUGH */
2344 default:
2345 /* anything else implies that we're done */
2346 done++;
2347 }
2348 /*
2349 * if we got here for some reason other than DNSRCH,
2350 * we only wanted one iteration of the loop, so stop.
2351 */
2352 if (!(res->options & RES_DNSRCH))
2353 done++;
2354 }
2355 }
2356
2357 /*
2358 * if we have not already tried the name "as is", do that now.
2359 * note that we do this regardless of how many dots were in the
2360 * name or whether it ends with a dot.
2361 */
2362 if (!tried_as_is) {
2363 ret = res_querydomainN(name, NULL, target, res);
2364 if (ret > 0)
2365 return ret;
2366 }
2367
2368 /*
2369 * if we got here, we didn't satisfy the search.
2370 * if we did an initial full query, return that query's h_errno
2371 * (note that we wouldn't be here if that query had succeeded).
2372 * else if we ever got a nodata, send that back as the reason.
2373 * else send back meaningless h_errno, that being the one from
2374 * the last DNSRCH we did.
2375 */
2376 if (saved_herrno != -1)
2377 h_errno = saved_herrno;
2378 else if (got_nodata)
2379 h_errno = NO_DATA;
2380 else if (got_servfail)
2381 h_errno = TRY_AGAIN;
2382 return -1;
2383 }
2384
2385 /*
2386 * Perform a call on res_query on the concatenation of name and domain,
2387 * removing a trailing dot from name if domain is NULL.
2388 */
2389 static int
res_querydomainN(const char * name,const char * domain,struct res_target * target,res_state res)2390 res_querydomainN(const char *name, const char *domain,
2391 struct res_target *target, res_state res)
2392 {
2393 char nbuf[MAXDNAME];
2394 const char *longname = nbuf;
2395 size_t n, d;
2396
2397 assert(name != NULL);
2398 /* XXX: target may be NULL??? */
2399
2400 #ifdef DEBUG
2401 if (res->options & RES_DEBUG)
2402 printf(";; res_querydomain(%s, %s)\n",
2403 name, domain?domain:"<Nil>");
2404 #endif
2405 if (domain == NULL) {
2406 /*
2407 * Check for trailing '.';
2408 * copy without '.' if present.
2409 */
2410 n = strlen(name);
2411 if (n + 1 > sizeof(nbuf)) {
2412 h_errno = NO_RECOVERY;
2413 return -1;
2414 }
2415 if (n > 0 && name[--n] == '.') {
2416 strncpy(nbuf, name, n);
2417 nbuf[n] = '\0';
2418 } else
2419 longname = name;
2420 } else {
2421 n = strlen(name);
2422 d = strlen(domain);
2423 if (n + 1 + d + 1 > sizeof(nbuf)) {
2424 h_errno = NO_RECOVERY;
2425 return -1;
2426 }
2427 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
2428 }
2429 return res_queryN(longname, target, res);
2430 }
2431