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 #include "private/bionic_defs.h"
111
112 typedef union sockaddr_union {
113 struct sockaddr generic;
114 struct sockaddr_in in;
115 struct sockaddr_in6 in6;
116 } sockaddr_union;
117
118 #define SUCCESS 0
119 #define ANY 0
120 #define YES 1
121 #define NO 0
122
123 static const char in_addrany[] = { 0, 0, 0, 0 };
124 static const char in_loopback[] = { 127, 0, 0, 1 };
125 #ifdef INET6
126 static const char in6_addrany[] = {
127 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
128 };
129 static const char in6_loopback[] = {
130 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
131 };
132 #endif
133
134 #if defined(__ANDROID__)
135 // This should be synchronized to ResponseCode.h
136 static const int DnsProxyQueryResult = 222;
137 #endif
138
139 static const struct afd {
140 int a_af;
141 int a_addrlen;
142 int a_socklen;
143 int a_off;
144 const char *a_addrany;
145 const char *a_loopback;
146 int a_scoped;
147 } afdl [] = {
148 #ifdef INET6
149 {PF_INET6, sizeof(struct in6_addr),
150 sizeof(struct sockaddr_in6),
151 offsetof(struct sockaddr_in6, sin6_addr),
152 in6_addrany, in6_loopback, 1},
153 #endif
154 {PF_INET, sizeof(struct in_addr),
155 sizeof(struct sockaddr_in),
156 offsetof(struct sockaddr_in, sin_addr),
157 in_addrany, in_loopback, 0},
158 {0, 0, 0, 0, NULL, NULL, 0},
159 };
160
161 struct explore {
162 int e_af;
163 int e_socktype;
164 int e_protocol;
165 const char *e_protostr;
166 int e_wild;
167 #define WILD_AF(ex) ((ex)->e_wild & 0x01)
168 #define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02)
169 #define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04)
170 };
171
172 static const struct explore explore[] = {
173 #if 0
174 { PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
175 #endif
176 #ifdef INET6
177 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
178 { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
179 { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 },
180 #endif
181 { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
182 { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
183 { PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
184 { PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
185 { PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
186 { PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 },
187 { -1, 0, 0, NULL, 0 },
188 };
189
190 #ifdef INET6
191 #define PTON_MAX 16
192 #else
193 #define PTON_MAX 4
194 #endif
195
196 static const ns_src default_dns_files[] = {
197 { NSSRC_FILES, NS_SUCCESS },
198 { NSSRC_DNS, NS_SUCCESS },
199 { 0, 0 }
200 };
201
202 #define MAXPACKET (8*1024)
203
204 typedef union {
205 HEADER hdr;
206 u_char buf[MAXPACKET];
207 } querybuf;
208
209 struct res_target {
210 struct res_target *next;
211 const char *name; /* domain name */
212 int qclass, qtype; /* class and type of query */
213 u_char *answer; /* buffer to put answer */
214 int anslen; /* size of answer buffer */
215 int n; /* result length */
216 };
217
218 static int str2number(const char *);
219 static int explore_fqdn(const struct addrinfo *, const char *,
220 const char *, struct addrinfo **, const struct android_net_context *);
221 static int explore_null(const struct addrinfo *,
222 const char *, struct addrinfo **);
223 static int explore_numeric(const struct addrinfo *, const char *,
224 const char *, struct addrinfo **, const char *);
225 static int explore_numeric_scope(const struct addrinfo *, const char *,
226 const char *, struct addrinfo **);
227 static int get_canonname(const struct addrinfo *,
228 struct addrinfo *, const char *);
229 static struct addrinfo *get_ai(const struct addrinfo *,
230 const struct afd *, const char *);
231 static int get_portmatch(const struct addrinfo *, const char *);
232 static int get_port(const struct addrinfo *, const char *, int);
233 static const struct afd *find_afd(int);
234 #ifdef INET6
235 static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *);
236 #endif
237
238 static struct addrinfo *getanswer(const querybuf *, int, const char *, int,
239 const struct addrinfo *);
240 static int _dns_getaddrinfo(void *, void *, va_list);
241 static void _sethtent(FILE **);
242 static void _endhtent(FILE **);
243 static struct addrinfo *_gethtent(FILE **, const char *,
244 const struct addrinfo *);
245 static int _files_getaddrinfo(void *, void *, va_list);
246 static int _find_src_addr(const struct sockaddr *, struct sockaddr *, unsigned , uid_t);
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 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
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 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
324 void
freeaddrinfo(struct addrinfo * ai)325 freeaddrinfo(struct addrinfo *ai)
326 {
327 struct addrinfo *next;
328
329 #if defined(__BIONIC__)
330 if (ai == NULL) return;
331 #else
332 _DIAGASSERT(ai != NULL);
333 #endif
334
335 do {
336 next = ai->ai_next;
337 if (ai->ai_canonname)
338 free(ai->ai_canonname);
339 /* no need to free(ai->ai_addr) */
340 free(ai);
341 ai = next;
342 } while (ai);
343 }
344
345 static int
str2number(const char * p)346 str2number(const char *p)
347 {
348 char *ep;
349 unsigned long v;
350
351 assert(p != NULL);
352
353 if (*p == '\0')
354 return -1;
355 ep = NULL;
356 errno = 0;
357 v = strtoul(p, &ep, 10);
358 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX)
359 return v;
360 else
361 return -1;
362 }
363
364 /*
365 * The following functions determine whether IPv4 or IPv6 connectivity is
366 * available in order to implement AI_ADDRCONFIG.
367 *
368 * Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is
369 * available, but whether addresses of the specified family are "configured
370 * on the local system". However, bionic doesn't currently support getifaddrs,
371 * so checking for connectivity is the next best thing.
372 */
373 static int
_have_ipv6(unsigned mark,uid_t uid)374 _have_ipv6(unsigned mark, uid_t uid) {
375 static const struct sockaddr_in6 sin6_test = {
376 .sin6_family = AF_INET6,
377 .sin6_addr.s6_addr = { // 2000::
378 0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
379 };
380 sockaddr_union addr = { .in6 = sin6_test };
381 return _find_src_addr(&addr.generic, NULL, mark, uid) == 1;
382 }
383
384 static int
_have_ipv4(unsigned mark,uid_t uid)385 _have_ipv4(unsigned mark, uid_t uid) {
386 static const struct sockaddr_in sin_test = {
387 .sin_family = AF_INET,
388 .sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8
389 };
390 sockaddr_union addr = { .in = sin_test };
391 return _find_src_addr(&addr.generic, NULL, mark, uid) == 1;
392 }
393
readBE32(FILE * fp,int32_t * result)394 bool readBE32(FILE* fp, int32_t* result) {
395 int32_t tmp;
396 if (fread(&tmp, sizeof(tmp), 1, fp) != 1) {
397 return false;
398 }
399 *result = ntohl(tmp);
400 return true;
401 }
402
403 #if defined(__ANDROID__)
404 // Returns 0 on success, else returns on error.
405 static int
android_getaddrinfo_proxy(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res,unsigned netid)406 android_getaddrinfo_proxy(
407 const char *hostname, const char *servname,
408 const struct addrinfo *hints, struct addrinfo **res, unsigned netid)
409 {
410 int success = 0;
411
412 // Clear this at start, as we use its non-NULLness later (in the
413 // error path) to decide if we have to free up any memory we
414 // allocated in the process (before failing).
415 *res = NULL;
416
417 // Bogus things we can't serialize. Don't use the proxy. These will fail - let them.
418 if ((hostname != NULL &&
419 strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) ||
420 (servname != NULL &&
421 strcspn(servname, " \n\r\t^'\"") != strlen(servname))) {
422 return EAI_NODATA;
423 }
424
425 FILE* proxy = android_open_proxy();
426 if (proxy == NULL) {
427 return EAI_SYSTEM;
428 }
429
430 netid = __netdClientDispatch.netIdForResolv(netid);
431
432 // Send the request.
433 if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d %u",
434 hostname == NULL ? "^" : hostname,
435 servname == NULL ? "^" : servname,
436 hints == NULL ? -1 : hints->ai_flags,
437 hints == NULL ? -1 : hints->ai_family,
438 hints == NULL ? -1 : hints->ai_socktype,
439 hints == NULL ? -1 : hints->ai_protocol,
440 netid) < 0) {
441 goto exit;
442 }
443 // literal NULL byte at end, required by FrameworkListener
444 if (fputc(0, proxy) == EOF ||
445 fflush(proxy) != 0) {
446 goto exit;
447 }
448
449 char buf[4];
450 // read result code for gethostbyaddr
451 if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) {
452 goto exit;
453 }
454
455 int result_code = (int)strtol(buf, NULL, 10);
456 // verify the code itself
457 if (result_code != DnsProxyQueryResult) {
458 fread(buf, 1, sizeof(buf), proxy);
459 goto exit;
460 }
461
462 struct addrinfo* ai = NULL;
463 struct addrinfo** nextres = res;
464 while (1) {
465 int32_t have_more;
466 if (!readBE32(proxy, &have_more)) {
467 break;
468 }
469 if (have_more == 0) {
470 success = 1;
471 break;
472 }
473
474 struct addrinfo* ai = calloc(1, sizeof(struct addrinfo) + sizeof(struct sockaddr_storage));
475 if (ai == NULL) {
476 break;
477 }
478 ai->ai_addr = (struct sockaddr*)(ai + 1);
479
480 // struct addrinfo {
481 // int ai_flags; /* AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST */
482 // int ai_family; /* PF_xxx */
483 // int ai_socktype; /* SOCK_xxx */
484 // int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
485 // socklen_t ai_addrlen; /* length of ai_addr */
486 // char *ai_canonname; /* canonical name for hostname */
487 // struct sockaddr *ai_addr; /* binary address */
488 // struct addrinfo *ai_next; /* next structure in linked list */
489 // };
490
491 // Read the struct piece by piece because we might be a 32-bit process
492 // talking to a 64-bit netd.
493 int32_t addr_len;
494 bool success =
495 readBE32(proxy, &ai->ai_flags) &&
496 readBE32(proxy, &ai->ai_family) &&
497 readBE32(proxy, &ai->ai_socktype) &&
498 readBE32(proxy, &ai->ai_protocol) &&
499 readBE32(proxy, &addr_len);
500 if (!success) {
501 break;
502 }
503
504 // Set ai_addrlen and read the ai_addr data.
505 ai->ai_addrlen = addr_len;
506 if (addr_len != 0) {
507 if ((size_t) addr_len > sizeof(struct sockaddr_storage)) {
508 // Bogus; too big.
509 break;
510 }
511 if (fread(ai->ai_addr, addr_len, 1, proxy) != 1) {
512 break;
513 }
514 }
515
516 // The string for ai_cannonname.
517 int32_t name_len;
518 if (!readBE32(proxy, &name_len)) {
519 break;
520 }
521 if (name_len != 0) {
522 ai->ai_canonname = (char*) malloc(name_len);
523 if (fread(ai->ai_canonname, name_len, 1, proxy) != 1) {
524 break;
525 }
526 if (ai->ai_canonname[name_len - 1] != '\0') {
527 // The proxy should be returning this
528 // NULL-terminated.
529 break;
530 }
531 }
532
533 *nextres = ai;
534 nextres = &ai->ai_next;
535 ai = NULL;
536 }
537
538 if (ai != NULL) {
539 // Clean up partially-built addrinfo that we never ended up
540 // attaching to the response.
541 freeaddrinfo(ai);
542 }
543 exit:
544 if (proxy != NULL) {
545 fclose(proxy);
546 }
547
548 if (success) {
549 return 0;
550 }
551
552 // Proxy failed;
553 // clean up memory we might've allocated.
554 if (*res) {
555 freeaddrinfo(*res);
556 *res = NULL;
557 }
558 return EAI_NODATA;
559 }
560 #endif
561
562 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
563 int
getaddrinfo(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res)564 getaddrinfo(const char *hostname, const char *servname,
565 const struct addrinfo *hints, struct addrinfo **res)
566 {
567 return android_getaddrinfofornet(hostname, servname, hints, NETID_UNSET, MARK_UNSET, res);
568 }
569
570 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
571 int
android_getaddrinfofornet(const char * hostname,const char * servname,const struct addrinfo * hints,unsigned netid,unsigned mark,struct addrinfo ** res)572 android_getaddrinfofornet(const char *hostname, const char *servname,
573 const struct addrinfo *hints, unsigned netid, unsigned mark, struct addrinfo **res)
574 {
575 struct android_net_context netcontext = {
576 .app_netid = netid,
577 .app_mark = mark,
578 .dns_netid = netid,
579 .dns_mark = mark,
580 .uid = NET_CONTEXT_INVALID_UID,
581 };
582 return android_getaddrinfofornetcontext(hostname, servname, hints, &netcontext, res);
583 }
584
585 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
586 int
android_getaddrinfofornetcontext(const char * hostname,const char * servname,const struct addrinfo * hints,const struct android_net_context * netcontext,struct addrinfo ** res)587 android_getaddrinfofornetcontext(const char *hostname, const char *servname,
588 const struct addrinfo *hints, const struct android_net_context *netcontext,
589 struct addrinfo **res)
590 {
591 struct addrinfo sentinel;
592 struct addrinfo *cur;
593 int error = 0;
594 struct addrinfo ai;
595 struct addrinfo ai0;
596 struct addrinfo *pai;
597 const struct explore *ex;
598
599 /* hostname is allowed to be NULL */
600 /* servname is allowed to be NULL */
601 /* hints is allowed to be NULL */
602 assert(res != NULL);
603 assert(netcontext != NULL);
604 memset(&sentinel, 0, sizeof(sentinel));
605 cur = &sentinel;
606 pai = &ai;
607 pai->ai_flags = 0;
608 pai->ai_family = PF_UNSPEC;
609 pai->ai_socktype = ANY;
610 pai->ai_protocol = ANY;
611 pai->ai_addrlen = 0;
612 pai->ai_canonname = NULL;
613 pai->ai_addr = NULL;
614 pai->ai_next = NULL;
615
616 if (hostname == NULL && servname == NULL)
617 return EAI_NONAME;
618 if (hints) {
619 /* error check for hints */
620 if (hints->ai_addrlen || hints->ai_canonname ||
621 hints->ai_addr || hints->ai_next)
622 ERR(EAI_BADHINTS); /* xxx */
623 if (hints->ai_flags & ~AI_MASK)
624 ERR(EAI_BADFLAGS);
625 switch (hints->ai_family) {
626 case PF_UNSPEC:
627 case PF_INET:
628 #ifdef INET6
629 case PF_INET6:
630 #endif
631 break;
632 default:
633 ERR(EAI_FAMILY);
634 }
635 memcpy(pai, hints, sizeof(*pai));
636
637 /*
638 * if both socktype/protocol are specified, check if they
639 * are meaningful combination.
640 */
641 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
642 for (ex = explore; ex->e_af >= 0; ex++) {
643 if (pai->ai_family != ex->e_af)
644 continue;
645 if (ex->e_socktype == ANY)
646 continue;
647 if (ex->e_protocol == ANY)
648 continue;
649 if (pai->ai_socktype == ex->e_socktype
650 && pai->ai_protocol != ex->e_protocol) {
651 ERR(EAI_BADHINTS);
652 }
653 }
654 }
655 }
656
657 /*
658 * check for special cases. (1) numeric servname is disallowed if
659 * socktype/protocol are left unspecified. (2) servname is disallowed
660 * for raw and other inet{,6} sockets.
661 */
662 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
663 #ifdef PF_INET6
664 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
665 #endif
666 ) {
667 ai0 = *pai; /* backup *pai */
668
669 if (pai->ai_family == PF_UNSPEC) {
670 #ifdef PF_INET6
671 pai->ai_family = PF_INET6;
672 #else
673 pai->ai_family = PF_INET;
674 #endif
675 }
676 error = get_portmatch(pai, servname);
677 if (error)
678 ERR(error);
679
680 *pai = ai0;
681 }
682
683 ai0 = *pai;
684
685 /* NULL hostname, or numeric hostname */
686 for (ex = explore; ex->e_af >= 0; ex++) {
687 *pai = ai0;
688
689 /* PF_UNSPEC entries are prepared for DNS queries only */
690 if (ex->e_af == PF_UNSPEC)
691 continue;
692
693 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
694 continue;
695 if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
696 continue;
697 if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
698 continue;
699
700 if (pai->ai_family == PF_UNSPEC)
701 pai->ai_family = ex->e_af;
702 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
703 pai->ai_socktype = ex->e_socktype;
704 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
705 pai->ai_protocol = ex->e_protocol;
706
707 if (hostname == NULL)
708 error = explore_null(pai, servname, &cur->ai_next);
709 else
710 error = explore_numeric_scope(pai, hostname, servname,
711 &cur->ai_next);
712
713 if (error)
714 goto free;
715
716 while (cur->ai_next)
717 cur = cur->ai_next;
718 }
719
720 /*
721 * XXX
722 * If numeric representation of AF1 can be interpreted as FQDN
723 * representation of AF2, we need to think again about the code below.
724 */
725 if (sentinel.ai_next)
726 goto good;
727
728 if (hostname == NULL)
729 ERR(EAI_NODATA);
730 if (pai->ai_flags & AI_NUMERICHOST)
731 ERR(EAI_NONAME);
732
733 #if defined(__ANDROID__)
734 int gai_error = android_getaddrinfo_proxy(
735 hostname, servname, hints, res, netcontext->app_netid);
736 if (gai_error != EAI_SYSTEM) {
737 return gai_error;
738 }
739 #endif
740
741 /*
742 * hostname as alphabetical name.
743 * we would like to prefer AF_INET6 than AF_INET, so we'll make a
744 * outer loop by AFs.
745 */
746 for (ex = explore; ex->e_af >= 0; ex++) {
747 *pai = ai0;
748
749 /* require exact match for family field */
750 if (pai->ai_family != ex->e_af)
751 continue;
752
753 if (!MATCH(pai->ai_socktype, ex->e_socktype,
754 WILD_SOCKTYPE(ex))) {
755 continue;
756 }
757 if (!MATCH(pai->ai_protocol, ex->e_protocol,
758 WILD_PROTOCOL(ex))) {
759 continue;
760 }
761
762 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
763 pai->ai_socktype = ex->e_socktype;
764 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
765 pai->ai_protocol = ex->e_protocol;
766
767 error = explore_fqdn(
768 pai, hostname, servname, &cur->ai_next, netcontext);
769
770 while (cur && cur->ai_next)
771 cur = cur->ai_next;
772 }
773
774 /* XXX */
775 if (sentinel.ai_next)
776 error = 0;
777
778 if (error)
779 goto free;
780 if (error == 0) {
781 if (sentinel.ai_next) {
782 good:
783 *res = sentinel.ai_next;
784 return SUCCESS;
785 } else
786 error = EAI_FAIL;
787 }
788 free:
789 bad:
790 if (sentinel.ai_next)
791 freeaddrinfo(sentinel.ai_next);
792 *res = NULL;
793 return error;
794 }
795
796 /*
797 * FQDN hostname, DNS lookup
798 */
799 static int
explore_fqdn(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,const struct android_net_context * netcontext)800 explore_fqdn(const struct addrinfo *pai, const char *hostname,
801 const char *servname, struct addrinfo **res,
802 const struct android_net_context *netcontext)
803 {
804 struct addrinfo *result;
805 struct addrinfo *cur;
806 int error = 0;
807 static const ns_dtab dtab[] = {
808 NS_FILES_CB(_files_getaddrinfo, NULL)
809 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
810 NS_NIS_CB(_yp_getaddrinfo, NULL)
811 { 0, 0, 0 }
812 };
813
814 assert(pai != NULL);
815 /* hostname may be NULL */
816 /* servname may be NULL */
817 assert(res != NULL);
818
819 result = NULL;
820
821 /*
822 * if the servname does not match socktype/protocol, ignore it.
823 */
824 if (get_portmatch(pai, servname) != 0)
825 return 0;
826
827 switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
828 default_dns_files, hostname, pai, netcontext)) {
829 case NS_TRYAGAIN:
830 error = EAI_AGAIN;
831 goto free;
832 case NS_UNAVAIL:
833 error = EAI_FAIL;
834 goto free;
835 case NS_NOTFOUND:
836 error = EAI_NODATA;
837 goto free;
838 case NS_SUCCESS:
839 error = 0;
840 for (cur = result; cur; cur = cur->ai_next) {
841 GET_PORT(cur, servname);
842 /* canonname should be filled already */
843 }
844 break;
845 }
846
847 *res = result;
848
849 return 0;
850
851 free:
852 if (result)
853 freeaddrinfo(result);
854 return error;
855 }
856
857 /*
858 * hostname == NULL.
859 * passive socket -> anyaddr (0.0.0.0 or ::)
860 * non-passive socket -> localhost (127.0.0.1 or ::1)
861 */
862 static int
explore_null(const struct addrinfo * pai,const char * servname,struct addrinfo ** res)863 explore_null(const struct addrinfo *pai, const char *servname,
864 struct addrinfo **res)
865 {
866 int s;
867 const struct afd *afd;
868 struct addrinfo *cur;
869 struct addrinfo sentinel;
870 int error;
871
872 assert(pai != NULL);
873 /* servname may be NULL */
874 assert(res != NULL);
875
876 *res = NULL;
877 sentinel.ai_next = NULL;
878 cur = &sentinel;
879
880 /*
881 * filter out AFs that are not supported by the kernel
882 * XXX errno?
883 */
884 s = socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
885 if (s < 0) {
886 if (errno != EMFILE)
887 return 0;
888 } else
889 close(s);
890
891 /*
892 * if the servname does not match socktype/protocol, ignore it.
893 */
894 if (get_portmatch(pai, servname) != 0)
895 return 0;
896
897 afd = find_afd(pai->ai_family);
898 if (afd == NULL)
899 return 0;
900
901 if (pai->ai_flags & AI_PASSIVE) {
902 GET_AI(cur->ai_next, afd, afd->a_addrany);
903 /* xxx meaningless?
904 * GET_CANONNAME(cur->ai_next, "anyaddr");
905 */
906 GET_PORT(cur->ai_next, servname);
907 } else {
908 GET_AI(cur->ai_next, afd, afd->a_loopback);
909 /* xxx meaningless?
910 * GET_CANONNAME(cur->ai_next, "localhost");
911 */
912 GET_PORT(cur->ai_next, servname);
913 }
914 cur = cur->ai_next;
915
916 *res = sentinel.ai_next;
917 return 0;
918
919 free:
920 if (sentinel.ai_next)
921 freeaddrinfo(sentinel.ai_next);
922 return error;
923 }
924
925 /*
926 * numeric hostname
927 */
928 static int
explore_numeric(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res,const char * canonname)929 explore_numeric(const struct addrinfo *pai, const char *hostname,
930 const char *servname, struct addrinfo **res, const char *canonname)
931 {
932 const struct afd *afd;
933 struct addrinfo *cur;
934 struct addrinfo sentinel;
935 int error;
936 char pton[PTON_MAX];
937
938 assert(pai != NULL);
939 /* hostname may be NULL */
940 /* servname may be NULL */
941 assert(res != NULL);
942
943 *res = NULL;
944 sentinel.ai_next = NULL;
945 cur = &sentinel;
946
947 /*
948 * if the servname does not match socktype/protocol, ignore it.
949 */
950 if (get_portmatch(pai, servname) != 0)
951 return 0;
952
953 afd = find_afd(pai->ai_family);
954 if (afd == NULL)
955 return 0;
956
957 switch (afd->a_af) {
958 #if 0 /*X/Open spec*/
959 case AF_INET:
960 if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
961 if (pai->ai_family == afd->a_af ||
962 pai->ai_family == PF_UNSPEC /*?*/) {
963 GET_AI(cur->ai_next, afd, pton);
964 GET_PORT(cur->ai_next, servname);
965 if ((pai->ai_flags & AI_CANONNAME)) {
966 /*
967 * Set the numeric address itself as
968 * the canonical name, based on a
969 * clarification in rfc2553bis-03.
970 */
971 GET_CANONNAME(cur->ai_next, canonname);
972 }
973 while (cur && cur->ai_next)
974 cur = cur->ai_next;
975 } else
976 ERR(EAI_FAMILY); /*xxx*/
977 }
978 break;
979 #endif
980 default:
981 if (inet_pton(afd->a_af, hostname, pton) == 1) {
982 if (pai->ai_family == afd->a_af ||
983 pai->ai_family == PF_UNSPEC /*?*/) {
984 GET_AI(cur->ai_next, afd, pton);
985 GET_PORT(cur->ai_next, servname);
986 if ((pai->ai_flags & AI_CANONNAME)) {
987 /*
988 * Set the numeric address itself as
989 * the canonical name, based on a
990 * clarification in rfc2553bis-03.
991 */
992 GET_CANONNAME(cur->ai_next, canonname);
993 }
994 while (cur->ai_next)
995 cur = cur->ai_next;
996 } else
997 ERR(EAI_FAMILY); /*xxx*/
998 }
999 break;
1000 }
1001
1002 *res = sentinel.ai_next;
1003 return 0;
1004
1005 free:
1006 bad:
1007 if (sentinel.ai_next)
1008 freeaddrinfo(sentinel.ai_next);
1009 return error;
1010 }
1011
1012 /*
1013 * numeric hostname with scope
1014 */
1015 static int
explore_numeric_scope(const struct addrinfo * pai,const char * hostname,const char * servname,struct addrinfo ** res)1016 explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
1017 const char *servname, struct addrinfo **res)
1018 {
1019 #if !defined(SCOPE_DELIMITER) || !defined(INET6)
1020 return explore_numeric(pai, hostname, servname, res, hostname);
1021 #else
1022 const struct afd *afd;
1023 struct addrinfo *cur;
1024 int error;
1025 char *cp, *hostname2 = NULL, *scope, *addr;
1026 struct sockaddr_in6 *sin6;
1027
1028 assert(pai != NULL);
1029 /* hostname may be NULL */
1030 /* servname may be NULL */
1031 assert(res != NULL);
1032
1033 /*
1034 * if the servname does not match socktype/protocol, ignore it.
1035 */
1036 if (get_portmatch(pai, servname) != 0)
1037 return 0;
1038
1039 afd = find_afd(pai->ai_family);
1040 if (afd == NULL)
1041 return 0;
1042
1043 if (!afd->a_scoped)
1044 return explore_numeric(pai, hostname, servname, res, hostname);
1045
1046 cp = strchr(hostname, SCOPE_DELIMITER);
1047 if (cp == NULL)
1048 return explore_numeric(pai, hostname, servname, res, hostname);
1049
1050 /*
1051 * Handle special case of <scoped_address><delimiter><scope id>
1052 */
1053 hostname2 = strdup(hostname);
1054 if (hostname2 == NULL)
1055 return EAI_MEMORY;
1056 /* terminate at the delimiter */
1057 hostname2[cp - hostname] = '\0';
1058 addr = hostname2;
1059 scope = cp + 1;
1060
1061 error = explore_numeric(pai, addr, servname, res, hostname);
1062 if (error == 0) {
1063 u_int32_t scopeid;
1064
1065 for (cur = *res; cur; cur = cur->ai_next) {
1066 if (cur->ai_family != AF_INET6)
1067 continue;
1068 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
1069 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
1070 free(hostname2);
1071 return(EAI_NODATA); /* XXX: is return OK? */
1072 }
1073 sin6->sin6_scope_id = scopeid;
1074 }
1075 }
1076
1077 free(hostname2);
1078
1079 return error;
1080 #endif
1081 }
1082
1083 static int
get_canonname(const struct addrinfo * pai,struct addrinfo * ai,const char * str)1084 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
1085 {
1086
1087 assert(pai != NULL);
1088 assert(ai != NULL);
1089 assert(str != NULL);
1090
1091 if ((pai->ai_flags & AI_CANONNAME) != 0) {
1092 ai->ai_canonname = strdup(str);
1093 if (ai->ai_canonname == NULL)
1094 return EAI_MEMORY;
1095 }
1096 return 0;
1097 }
1098
1099 static struct addrinfo *
get_ai(const struct addrinfo * pai,const struct afd * afd,const char * addr)1100 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
1101 {
1102 char *p;
1103 struct addrinfo *ai;
1104
1105 assert(pai != NULL);
1106 assert(afd != NULL);
1107 assert(addr != NULL);
1108
1109 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
1110 + (afd->a_socklen));
1111 if (ai == NULL)
1112 return NULL;
1113
1114 memcpy(ai, pai, sizeof(struct addrinfo));
1115 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1116 memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1117
1118 #ifdef HAVE_SA_LEN
1119 ai->ai_addr->sa_len = afd->a_socklen;
1120 #endif
1121
1122 ai->ai_addrlen = afd->a_socklen;
1123 #if defined (__alpha__) || (defined(__i386__) && defined(_LP64)) || defined(__sparc64__)
1124 ai->__ai_pad0 = 0;
1125 #endif
1126 ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1127 p = (char *)(void *)(ai->ai_addr);
1128 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
1129 return ai;
1130 }
1131
1132 static int
get_portmatch(const struct addrinfo * ai,const char * servname)1133 get_portmatch(const struct addrinfo *ai, const char *servname)
1134 {
1135
1136 assert(ai != NULL);
1137 /* servname may be NULL */
1138
1139 return get_port(ai, servname, 1);
1140 }
1141
1142 static int
get_port(const struct addrinfo * ai,const char * servname,int matchonly)1143 get_port(const struct addrinfo *ai, const char *servname, int matchonly)
1144 {
1145 const char *proto;
1146 struct servent *sp;
1147 int port;
1148 int allownumeric;
1149
1150 assert(ai != NULL);
1151 /* servname may be NULL */
1152
1153 if (servname == NULL)
1154 return 0;
1155 switch (ai->ai_family) {
1156 case AF_INET:
1157 #ifdef AF_INET6
1158 case AF_INET6:
1159 #endif
1160 break;
1161 default:
1162 return 0;
1163 }
1164
1165 switch (ai->ai_socktype) {
1166 case SOCK_RAW:
1167 return EAI_SERVICE;
1168 case SOCK_DGRAM:
1169 case SOCK_STREAM:
1170 allownumeric = 1;
1171 break;
1172 case ANY:
1173 #if 1 /* ANDROID-SPECIFIC CHANGE TO MATCH GLIBC */
1174 allownumeric = 1;
1175 #else
1176 allownumeric = 0;
1177 #endif
1178 break;
1179 default:
1180 return EAI_SOCKTYPE;
1181 }
1182
1183 port = str2number(servname);
1184 if (port >= 0) {
1185 if (!allownumeric)
1186 return EAI_SERVICE;
1187 if (port < 0 || port > 65535)
1188 return EAI_SERVICE;
1189 port = htons(port);
1190 } else {
1191 if (ai->ai_flags & AI_NUMERICSERV)
1192 return EAI_NONAME;
1193
1194 switch (ai->ai_socktype) {
1195 case SOCK_DGRAM:
1196 proto = "udp";
1197 break;
1198 case SOCK_STREAM:
1199 proto = "tcp";
1200 break;
1201 default:
1202 proto = NULL;
1203 break;
1204 }
1205
1206 if ((sp = getservbyname(servname, proto)) == NULL)
1207 return EAI_SERVICE;
1208 port = sp->s_port;
1209 }
1210
1211 if (!matchonly) {
1212 switch (ai->ai_family) {
1213 case AF_INET:
1214 ((struct sockaddr_in *)(void *)
1215 ai->ai_addr)->sin_port = port;
1216 break;
1217 #ifdef INET6
1218 case AF_INET6:
1219 ((struct sockaddr_in6 *)(void *)
1220 ai->ai_addr)->sin6_port = port;
1221 break;
1222 #endif
1223 }
1224 }
1225
1226 return 0;
1227 }
1228
1229 static const struct afd *
find_afd(int af)1230 find_afd(int af)
1231 {
1232 const struct afd *afd;
1233
1234 if (af == PF_UNSPEC)
1235 return NULL;
1236 for (afd = afdl; afd->a_af; afd++) {
1237 if (afd->a_af == af)
1238 return afd;
1239 }
1240 return NULL;
1241 }
1242
1243 #ifdef INET6
1244 /* convert a string to a scope identifier. XXX: IPv6 specific */
1245 static int
ip6_str2scopeid(char * scope,struct sockaddr_in6 * sin6,u_int32_t * scopeid)1246 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
1247 {
1248 u_long lscopeid;
1249 struct in6_addr *a6;
1250 char *ep;
1251
1252 assert(scope != NULL);
1253 assert(sin6 != NULL);
1254 assert(scopeid != NULL);
1255
1256 a6 = &sin6->sin6_addr;
1257
1258 /* empty scopeid portion is invalid */
1259 if (*scope == '\0')
1260 return -1;
1261
1262 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
1263 /*
1264 * We currently assume a one-to-one mapping between links
1265 * and interfaces, so we simply use interface indices for
1266 * like-local scopes.
1267 */
1268 *scopeid = if_nametoindex(scope);
1269 if (*scopeid == 0)
1270 goto trynumeric;
1271 return 0;
1272 }
1273
1274 /* still unclear about literal, allow numeric only - placeholder */
1275 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1276 goto trynumeric;
1277 if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1278 goto trynumeric;
1279 else
1280 goto trynumeric; /* global */
1281
1282 /* try to convert to a numeric id as a last resort */
1283 trynumeric:
1284 errno = 0;
1285 lscopeid = strtoul(scope, &ep, 10);
1286 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
1287 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
1288 return 0;
1289 else
1290 return -1;
1291 }
1292 #endif
1293
1294 /* code duplicate with gethnamaddr.c */
1295
1296 static const char AskedForGot[] =
1297 "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1298
1299 #define BOUNDED_INCR(x) \
1300 do { \
1301 BOUNDS_CHECK(cp, x); \
1302 cp += (x); \
1303 } while (/*CONSTCOND*/0)
1304
1305 #define BOUNDS_CHECK(ptr, count) \
1306 do { \
1307 if (eom - (ptr) < (count)) { h_errno = NO_RECOVERY; return NULL; } \
1308 } while (/*CONSTCOND*/0)
1309
1310 static struct addrinfo *
getanswer(const querybuf * answer,int anslen,const char * qname,int qtype,const struct addrinfo * pai)1311 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
1312 const struct addrinfo *pai)
1313 {
1314 struct addrinfo sentinel, *cur;
1315 struct addrinfo ai;
1316 const struct afd *afd;
1317 char *canonname;
1318 const HEADER *hp;
1319 const u_char *cp;
1320 int n;
1321 const u_char *eom;
1322 char *bp, *ep;
1323 int type, class, ancount, qdcount;
1324 int haveanswer, had_error;
1325 char tbuf[MAXDNAME];
1326 int (*name_ok) (const char *);
1327 char hostbuf[8*1024];
1328
1329 assert(answer != NULL);
1330 assert(qname != NULL);
1331 assert(pai != NULL);
1332
1333 memset(&sentinel, 0, sizeof(sentinel));
1334 cur = &sentinel;
1335
1336 canonname = NULL;
1337 eom = answer->buf + anslen;
1338 switch (qtype) {
1339 case T_A:
1340 case T_AAAA:
1341 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
1342 name_ok = res_hnok;
1343 break;
1344 default:
1345 return NULL; /* XXX should be abort(); */
1346 }
1347 /*
1348 * find first satisfactory answer
1349 */
1350 hp = &answer->hdr;
1351 ancount = ntohs(hp->ancount);
1352 qdcount = ntohs(hp->qdcount);
1353 bp = hostbuf;
1354 ep = hostbuf + sizeof hostbuf;
1355 cp = answer->buf;
1356 BOUNDED_INCR(HFIXEDSZ);
1357 if (qdcount != 1) {
1358 h_errno = NO_RECOVERY;
1359 return (NULL);
1360 }
1361 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
1362 if ((n < 0) || !(*name_ok)(bp)) {
1363 h_errno = NO_RECOVERY;
1364 return (NULL);
1365 }
1366 BOUNDED_INCR(n + QFIXEDSZ);
1367 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
1368 /* res_send() has already verified that the query name is the
1369 * same as the one we sent; this just gets the expanded name
1370 * (i.e., with the succeeding search-domain tacked on).
1371 */
1372 n = strlen(bp) + 1; /* for the \0 */
1373 if (n >= MAXHOSTNAMELEN) {
1374 h_errno = NO_RECOVERY;
1375 return (NULL);
1376 }
1377 canonname = bp;
1378 bp += n;
1379 /* The qname can be abbreviated, but h_name is now absolute. */
1380 qname = canonname;
1381 }
1382 haveanswer = 0;
1383 had_error = 0;
1384 while (ancount-- > 0 && cp < eom && !had_error) {
1385 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
1386 if ((n < 0) || !(*name_ok)(bp)) {
1387 had_error++;
1388 continue;
1389 }
1390 cp += n; /* name */
1391 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
1392 type = _getshort(cp);
1393 cp += INT16SZ; /* type */
1394 class = _getshort(cp);
1395 cp += INT16SZ + INT32SZ; /* class, TTL */
1396 n = _getshort(cp);
1397 cp += INT16SZ; /* len */
1398 BOUNDS_CHECK(cp, n);
1399 if (class != C_IN) {
1400 /* XXX - debug? syslog? */
1401 cp += n;
1402 continue; /* XXX - had_error++ ? */
1403 }
1404 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
1405 type == T_CNAME) {
1406 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
1407 if ((n < 0) || !(*name_ok)(tbuf)) {
1408 had_error++;
1409 continue;
1410 }
1411 cp += n;
1412 /* Get canonical name. */
1413 n = strlen(tbuf) + 1; /* for the \0 */
1414 if (n > ep - bp || n >= MAXHOSTNAMELEN) {
1415 had_error++;
1416 continue;
1417 }
1418 strlcpy(bp, tbuf, (size_t)(ep - bp));
1419 canonname = bp;
1420 bp += n;
1421 continue;
1422 }
1423 if (qtype == T_ANY) {
1424 if (!(type == T_A || type == T_AAAA)) {
1425 cp += n;
1426 continue;
1427 }
1428 } else if (type != qtype) {
1429 if (type != T_KEY && type != T_SIG)
1430 syslog(LOG_NOTICE|LOG_AUTH,
1431 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
1432 qname, p_class(C_IN), p_type(qtype),
1433 p_type(type));
1434 cp += n;
1435 continue; /* XXX - had_error++ ? */
1436 }
1437 switch (type) {
1438 case T_A:
1439 case T_AAAA:
1440 if (strcasecmp(canonname, bp) != 0) {
1441 syslog(LOG_NOTICE|LOG_AUTH,
1442 AskedForGot, canonname, bp);
1443 cp += n;
1444 continue; /* XXX - had_error++ ? */
1445 }
1446 if (type == T_A && n != INADDRSZ) {
1447 cp += n;
1448 continue;
1449 }
1450 if (type == T_AAAA && n != IN6ADDRSZ) {
1451 cp += n;
1452 continue;
1453 }
1454 if (type == T_AAAA) {
1455 struct in6_addr in6;
1456 memcpy(&in6, cp, IN6ADDRSZ);
1457 if (IN6_IS_ADDR_V4MAPPED(&in6)) {
1458 cp += n;
1459 continue;
1460 }
1461 }
1462 if (!haveanswer) {
1463 int nn;
1464
1465 canonname = bp;
1466 nn = strlen(bp) + 1; /* for the \0 */
1467 bp += nn;
1468 }
1469
1470 /* don't overwrite pai */
1471 ai = *pai;
1472 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
1473 afd = find_afd(ai.ai_family);
1474 if (afd == NULL) {
1475 cp += n;
1476 continue;
1477 }
1478 cur->ai_next = get_ai(&ai, afd, (const char *)cp);
1479 if (cur->ai_next == NULL)
1480 had_error++;
1481 while (cur && cur->ai_next)
1482 cur = cur->ai_next;
1483 cp += n;
1484 break;
1485 default:
1486 abort();
1487 }
1488 if (!had_error)
1489 haveanswer++;
1490 }
1491 if (haveanswer) {
1492 if (!canonname)
1493 (void)get_canonname(pai, sentinel.ai_next, qname);
1494 else
1495 (void)get_canonname(pai, sentinel.ai_next, canonname);
1496 h_errno = NETDB_SUCCESS;
1497 return sentinel.ai_next;
1498 }
1499
1500 h_errno = NO_RECOVERY;
1501 return NULL;
1502 }
1503
1504 struct addrinfo_sort_elem {
1505 struct addrinfo *ai;
1506 int has_src_addr;
1507 sockaddr_union src_addr;
1508 int original_order;
1509 };
1510
1511 /*ARGSUSED*/
1512 static int
_get_scope(const struct sockaddr * addr)1513 _get_scope(const struct sockaddr *addr)
1514 {
1515 if (addr->sa_family == AF_INET6) {
1516 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1517 if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) {
1518 return IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr);
1519 } else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) ||
1520 IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) {
1521 /*
1522 * RFC 4291 section 2.5.3 says loopback is to be treated as having
1523 * link-local scope.
1524 */
1525 return IPV6_ADDR_SCOPE_LINKLOCAL;
1526 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
1527 return IPV6_ADDR_SCOPE_SITELOCAL;
1528 } else {
1529 return IPV6_ADDR_SCOPE_GLOBAL;
1530 }
1531 } else if (addr->sa_family == AF_INET) {
1532 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
1533 unsigned long int na = ntohl(addr4->sin_addr.s_addr);
1534
1535 if (IN_LOOPBACK(na) || /* 127.0.0.0/8 */
1536 (na & 0xffff0000) == 0xa9fe0000) { /* 169.254.0.0/16 */
1537 return IPV6_ADDR_SCOPE_LINKLOCAL;
1538 } else {
1539 /*
1540 * RFC 6724 section 3.2. Other IPv4 addresses, including private addresses
1541 * and shared addresses (100.64.0.0/10), are assigned global scope.
1542 */
1543 return IPV6_ADDR_SCOPE_GLOBAL;
1544 }
1545 } else {
1546 /*
1547 * This should never happen.
1548 * Return a scope with low priority as a last resort.
1549 */
1550 return IPV6_ADDR_SCOPE_NODELOCAL;
1551 }
1552 }
1553
1554 /* These macros are modelled after the ones in <netinet/in6.h>. */
1555
1556 /* RFC 4380, section 2.6 */
1557 #define IN6_IS_ADDR_TEREDO(a) \
1558 ((*(const uint32_t *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000)))
1559
1560 /* RFC 3056, section 2. */
1561 #define IN6_IS_ADDR_6TO4(a) \
1562 (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02))
1563
1564 /* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */
1565 #define IN6_IS_ADDR_6BONE(a) \
1566 (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe))
1567
1568 /*
1569 * Get the label for a given IPv4/IPv6 address.
1570 * RFC 6724, section 2.1.
1571 */
1572
1573 /*ARGSUSED*/
1574 static int
_get_label(const struct sockaddr * addr)1575 _get_label(const struct sockaddr *addr)
1576 {
1577 if (addr->sa_family == AF_INET) {
1578 return 4;
1579 } else if (addr->sa_family == AF_INET6) {
1580 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *) addr;
1581 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
1582 return 0;
1583 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
1584 return 4;
1585 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
1586 return 2;
1587 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
1588 return 5;
1589 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
1590 return 13;
1591 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) {
1592 return 3;
1593 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
1594 return 11;
1595 } else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
1596 return 12;
1597 } else {
1598 /* All other IPv6 addresses, including global unicast addresses. */
1599 return 1;
1600 }
1601 } else {
1602 /*
1603 * This should never happen.
1604 * Return a semi-random label as a last resort.
1605 */
1606 return 1;
1607 }
1608 }
1609
1610 /*
1611 * Get the precedence for a given IPv4/IPv6 address.
1612 * RFC 6724, section 2.1.
1613 */
1614
1615 /*ARGSUSED*/
1616 static int
_get_precedence(const struct sockaddr * addr)1617 _get_precedence(const struct sockaddr *addr)
1618 {
1619 if (addr->sa_family == AF_INET) {
1620 return 35;
1621 } else if (addr->sa_family == AF_INET6) {
1622 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
1623 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
1624 return 50;
1625 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
1626 return 35;
1627 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
1628 return 30;
1629 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
1630 return 5;
1631 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
1632 return 3;
1633 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) ||
1634 IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) ||
1635 IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
1636 return 1;
1637 } else {
1638 /* All other IPv6 addresses, including global unicast addresses. */
1639 return 40;
1640 }
1641 } else {
1642 return 1;
1643 }
1644 }
1645
1646 /*
1647 * Find number of matching initial bits between the two addresses a1 and a2.
1648 */
1649
1650 /*ARGSUSED*/
1651 static int
_common_prefix_len(const struct in6_addr * a1,const struct in6_addr * a2)1652 _common_prefix_len(const struct in6_addr *a1, const struct in6_addr *a2)
1653 {
1654 const char *p1 = (const char *)a1;
1655 const char *p2 = (const char *)a2;
1656 unsigned i;
1657
1658 for (i = 0; i < sizeof(*a1); ++i) {
1659 int x, j;
1660
1661 if (p1[i] == p2[i]) {
1662 continue;
1663 }
1664 x = p1[i] ^ p2[i];
1665 for (j = 0; j < CHAR_BIT; ++j) {
1666 if (x & (1 << (CHAR_BIT - 1))) {
1667 return i * CHAR_BIT + j;
1668 }
1669 x <<= 1;
1670 }
1671 }
1672 return sizeof(*a1) * CHAR_BIT;
1673 }
1674
1675 /*
1676 * Compare two source/destination address pairs.
1677 * RFC 6724, section 6.
1678 */
1679
1680 /*ARGSUSED*/
1681 static int
_rfc6724_compare(const void * ptr1,const void * ptr2)1682 _rfc6724_compare(const void *ptr1, const void* ptr2)
1683 {
1684 const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1;
1685 const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2;
1686 int scope_src1, scope_dst1, scope_match1;
1687 int scope_src2, scope_dst2, scope_match2;
1688 int label_src1, label_dst1, label_match1;
1689 int label_src2, label_dst2, label_match2;
1690 int precedence1, precedence2;
1691 int prefixlen1, prefixlen2;
1692
1693 /* Rule 1: Avoid unusable destinations. */
1694 if (a1->has_src_addr != a2->has_src_addr) {
1695 return a2->has_src_addr - a1->has_src_addr;
1696 }
1697
1698 /* Rule 2: Prefer matching scope. */
1699 scope_src1 = _get_scope(&a1->src_addr.generic);
1700 scope_dst1 = _get_scope(a1->ai->ai_addr);
1701 scope_match1 = (scope_src1 == scope_dst1);
1702
1703 scope_src2 = _get_scope(&a2->src_addr.generic);
1704 scope_dst2 = _get_scope(a2->ai->ai_addr);
1705 scope_match2 = (scope_src2 == scope_dst2);
1706
1707 if (scope_match1 != scope_match2) {
1708 return scope_match2 - scope_match1;
1709 }
1710
1711 /*
1712 * Rule 3: Avoid deprecated addresses.
1713 * TODO(sesse): We don't currently have a good way of finding this.
1714 */
1715
1716 /*
1717 * Rule 4: Prefer home addresses.
1718 * TODO(sesse): We don't currently have a good way of finding this.
1719 */
1720
1721 /* Rule 5: Prefer matching label. */
1722 label_src1 = _get_label(&a1->src_addr.generic);
1723 label_dst1 = _get_label(a1->ai->ai_addr);
1724 label_match1 = (label_src1 == label_dst1);
1725
1726 label_src2 = _get_label(&a2->src_addr.generic);
1727 label_dst2 = _get_label(a2->ai->ai_addr);
1728 label_match2 = (label_src2 == label_dst2);
1729
1730 if (label_match1 != label_match2) {
1731 return label_match2 - label_match1;
1732 }
1733
1734 /* Rule 6: Prefer higher precedence. */
1735 precedence1 = _get_precedence(a1->ai->ai_addr);
1736 precedence2 = _get_precedence(a2->ai->ai_addr);
1737 if (precedence1 != precedence2) {
1738 return precedence2 - precedence1;
1739 }
1740
1741 /*
1742 * Rule 7: Prefer native transport.
1743 * TODO(sesse): We don't currently have a good way of finding this.
1744 */
1745
1746 /* Rule 8: Prefer smaller scope. */
1747 if (scope_dst1 != scope_dst2) {
1748 return scope_dst1 - scope_dst2;
1749 }
1750
1751 /*
1752 * Rule 9: Use longest matching prefix.
1753 * We implement this for IPv6 only, as the rules in RFC 6724 don't seem
1754 * to work very well directly applied to IPv4. (glibc uses information from
1755 * the routing table for a custom IPv4 implementation here.)
1756 */
1757 if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 &&
1758 a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6) {
1759 const struct sockaddr_in6 *a1_src = &a1->src_addr.in6;
1760 const struct sockaddr_in6 *a1_dst = (const struct sockaddr_in6 *)a1->ai->ai_addr;
1761 const struct sockaddr_in6 *a2_src = &a2->src_addr.in6;
1762 const struct sockaddr_in6 *a2_dst = (const struct sockaddr_in6 *)a2->ai->ai_addr;
1763 prefixlen1 = _common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr);
1764 prefixlen2 = _common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr);
1765 if (prefixlen1 != prefixlen2) {
1766 return prefixlen2 - prefixlen1;
1767 }
1768 }
1769
1770 /*
1771 * Rule 10: Leave the order unchanged.
1772 * We need this since qsort() is not necessarily stable.
1773 */
1774 return a1->original_order - a2->original_order;
1775 }
1776
1777 /*
1778 * Find the source address that will be used if trying to connect to the given
1779 * address. src_addr must be large enough to hold a struct sockaddr_in6.
1780 *
1781 * Returns 1 if a source address was found, 0 if the address is unreachable,
1782 * and -1 if a fatal error occurred. If 0 or -1, the contents of src_addr are
1783 * undefined.
1784 */
1785
1786 /*ARGSUSED*/
1787 static int
_find_src_addr(const struct sockaddr * addr,struct sockaddr * src_addr,unsigned mark,uid_t uid)1788 _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned mark, uid_t uid)
1789 {
1790 int sock;
1791 int ret;
1792 socklen_t len;
1793
1794 switch (addr->sa_family) {
1795 case AF_INET:
1796 len = sizeof(struct sockaddr_in);
1797 break;
1798 case AF_INET6:
1799 len = sizeof(struct sockaddr_in6);
1800 break;
1801 default:
1802 /* No known usable source address for non-INET families. */
1803 return 0;
1804 }
1805
1806 sock = socket(addr->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
1807 if (sock == -1) {
1808 if (errno == EAFNOSUPPORT) {
1809 return 0;
1810 } else {
1811 return -1;
1812 }
1813 }
1814 if (mark != MARK_UNSET && setsockopt(sock, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0) {
1815 close(sock);
1816 return 0;
1817 }
1818 if (uid > 0 && uid != NET_CONTEXT_INVALID_UID && fchown(sock, uid, (gid_t)-1) < 0) {
1819 close(sock);
1820 return 0;
1821 }
1822 do {
1823 ret = __connect(sock, addr, len);
1824 } while (ret == -1 && errno == EINTR);
1825
1826 if (ret == -1) {
1827 close(sock);
1828 return 0;
1829 }
1830
1831 if (src_addr && getsockname(sock, src_addr, &len) == -1) {
1832 close(sock);
1833 return -1;
1834 }
1835 close(sock);
1836 return 1;
1837 }
1838
1839 /*
1840 * Sort the linked list starting at sentinel->ai_next in RFC6724 order.
1841 * Will leave the list unchanged if an error occurs.
1842 */
1843
1844 /*ARGSUSED*/
1845 static void
_rfc6724_sort(struct addrinfo * list_sentinel,unsigned mark,uid_t uid)1846 _rfc6724_sort(struct addrinfo *list_sentinel, unsigned mark, uid_t uid)
1847 {
1848 struct addrinfo *cur;
1849 int nelem = 0, i;
1850 struct addrinfo_sort_elem *elems;
1851
1852 cur = list_sentinel->ai_next;
1853 while (cur) {
1854 ++nelem;
1855 cur = cur->ai_next;
1856 }
1857
1858 elems = (struct addrinfo_sort_elem *)malloc(nelem * sizeof(struct addrinfo_sort_elem));
1859 if (elems == NULL) {
1860 goto error;
1861 }
1862
1863 /*
1864 * Convert the linked list to an array that also contains the candidate
1865 * source address for each destination address.
1866 */
1867 for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) {
1868 int has_src_addr;
1869 assert(cur != NULL);
1870 elems[i].ai = cur;
1871 elems[i].original_order = i;
1872
1873 has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic, mark, uid);
1874 if (has_src_addr == -1) {
1875 goto error;
1876 }
1877 elems[i].has_src_addr = has_src_addr;
1878 }
1879
1880 /* Sort the addresses, and rearrange the linked list so it matches the sorted order. */
1881 qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem), _rfc6724_compare);
1882
1883 list_sentinel->ai_next = elems[0].ai;
1884 for (i = 0; i < nelem - 1; ++i) {
1885 elems[i].ai->ai_next = elems[i + 1].ai;
1886 }
1887 elems[nelem - 1].ai->ai_next = NULL;
1888
1889 error:
1890 free(elems);
1891 }
1892
1893 /*ARGSUSED*/
1894 static int
_dns_getaddrinfo(void * rv,void * cb_data,va_list ap)1895 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
1896 {
1897 struct addrinfo *ai;
1898 querybuf *buf, *buf2;
1899 const char *name;
1900 const struct addrinfo *pai;
1901 struct addrinfo sentinel, *cur;
1902 struct res_target q, q2;
1903 res_state res;
1904 const struct android_net_context *netcontext;
1905
1906 name = va_arg(ap, char *);
1907 pai = va_arg(ap, const struct addrinfo *);
1908 netcontext = va_arg(ap, const struct android_net_context *);
1909 //fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name);
1910
1911 memset(&q, 0, sizeof(q));
1912 memset(&q2, 0, sizeof(q2));
1913 memset(&sentinel, 0, sizeof(sentinel));
1914 cur = &sentinel;
1915
1916 buf = malloc(sizeof(*buf));
1917 if (buf == NULL) {
1918 h_errno = NETDB_INTERNAL;
1919 return NS_NOTFOUND;
1920 }
1921 buf2 = malloc(sizeof(*buf2));
1922 if (buf2 == NULL) {
1923 free(buf);
1924 h_errno = NETDB_INTERNAL;
1925 return NS_NOTFOUND;
1926 }
1927
1928 switch (pai->ai_family) {
1929 case AF_UNSPEC:
1930 /* prefer IPv6 */
1931 q.name = name;
1932 q.qclass = C_IN;
1933 q.answer = buf->buf;
1934 q.anslen = sizeof(buf->buf);
1935 int query_ipv6 = 1, query_ipv4 = 1;
1936 if (pai->ai_flags & AI_ADDRCONFIG) {
1937 query_ipv6 = _have_ipv6(netcontext->app_mark, netcontext->uid);
1938 query_ipv4 = _have_ipv4(netcontext->app_mark, netcontext->uid);
1939 }
1940 if (query_ipv6) {
1941 q.qtype = T_AAAA;
1942 if (query_ipv4) {
1943 q.next = &q2;
1944 q2.name = name;
1945 q2.qclass = C_IN;
1946 q2.qtype = T_A;
1947 q2.answer = buf2->buf;
1948 q2.anslen = sizeof(buf2->buf);
1949 }
1950 } else if (query_ipv4) {
1951 q.qtype = T_A;
1952 } else {
1953 free(buf);
1954 free(buf2);
1955 return NS_NOTFOUND;
1956 }
1957 break;
1958 case AF_INET:
1959 q.name = name;
1960 q.qclass = C_IN;
1961 q.qtype = T_A;
1962 q.answer = buf->buf;
1963 q.anslen = sizeof(buf->buf);
1964 break;
1965 case AF_INET6:
1966 q.name = name;
1967 q.qclass = C_IN;
1968 q.qtype = T_AAAA;
1969 q.answer = buf->buf;
1970 q.anslen = sizeof(buf->buf);
1971 break;
1972 default:
1973 free(buf);
1974 free(buf2);
1975 return NS_UNAVAIL;
1976 }
1977
1978 res = __res_get_state();
1979 if (res == NULL) {
1980 free(buf);
1981 free(buf2);
1982 return NS_NOTFOUND;
1983 }
1984
1985 /* this just sets our netid val in the thread private data so we don't have to
1986 * modify the api's all the way down to res_send.c's res_nsend. We could
1987 * fully populate the thread private data here, but if we get down there
1988 * and have a cache hit that would be wasted, so we do the rest there on miss
1989 */
1990 res_setnetcontext(res, netcontext);
1991 if (res_searchN(name, &q, res) < 0) {
1992 __res_put_state(res);
1993 free(buf);
1994 free(buf2);
1995 return NS_NOTFOUND;
1996 }
1997 ai = getanswer(buf, q.n, q.name, q.qtype, pai);
1998 if (ai) {
1999 cur->ai_next = ai;
2000 while (cur && cur->ai_next)
2001 cur = cur->ai_next;
2002 }
2003 if (q.next) {
2004 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai);
2005 if (ai)
2006 cur->ai_next = ai;
2007 }
2008 free(buf);
2009 free(buf2);
2010 if (sentinel.ai_next == NULL) {
2011 __res_put_state(res);
2012 switch (h_errno) {
2013 case HOST_NOT_FOUND:
2014 return NS_NOTFOUND;
2015 case TRY_AGAIN:
2016 return NS_TRYAGAIN;
2017 default:
2018 return NS_UNAVAIL;
2019 }
2020 }
2021
2022 _rfc6724_sort(&sentinel, netcontext->app_mark, netcontext->uid);
2023
2024 __res_put_state(res);
2025
2026 *((struct addrinfo **)rv) = sentinel.ai_next;
2027 return NS_SUCCESS;
2028 }
2029
2030 static void
_sethtent(FILE ** hostf)2031 _sethtent(FILE **hostf)
2032 {
2033
2034 if (!*hostf)
2035 *hostf = fopen(_PATH_HOSTS, "re");
2036 else
2037 rewind(*hostf);
2038 }
2039
2040 static void
_endhtent(FILE ** hostf)2041 _endhtent(FILE **hostf)
2042 {
2043
2044 if (*hostf) {
2045 (void) fclose(*hostf);
2046 *hostf = NULL;
2047 }
2048 }
2049
2050 static struct addrinfo *
_gethtent(FILE ** hostf,const char * name,const struct addrinfo * pai)2051 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai)
2052 {
2053 char *p;
2054 char *cp, *tname, *cname;
2055 struct addrinfo hints, *res0, *res;
2056 int error;
2057 const char *addr;
2058 char hostbuf[8*1024];
2059
2060 // fprintf(stderr, "_gethtent() name = '%s'\n", name);
2061 assert(name != NULL);
2062 assert(pai != NULL);
2063
2064 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re")))
2065 return (NULL);
2066 again:
2067 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf)))
2068 return (NULL);
2069 if (*p == '#')
2070 goto again;
2071 if (!(cp = strpbrk(p, "#\n")))
2072 goto again;
2073 *cp = '\0';
2074 if (!(cp = strpbrk(p, " \t")))
2075 goto again;
2076 *cp++ = '\0';
2077 addr = p;
2078 /* if this is not something we're looking for, skip it. */
2079 cname = NULL;
2080 while (cp && *cp) {
2081 if (*cp == ' ' || *cp == '\t') {
2082 cp++;
2083 continue;
2084 }
2085 if (!cname)
2086 cname = cp;
2087 tname = cp;
2088 if ((cp = strpbrk(cp, " \t")) != NULL)
2089 *cp++ = '\0';
2090 // fprintf(stderr, "\ttname = '%s'", tname);
2091 if (strcasecmp(name, tname) == 0)
2092 goto found;
2093 }
2094 goto again;
2095
2096 found:
2097 hints = *pai;
2098 hints.ai_flags = AI_NUMERICHOST;
2099 error = getaddrinfo(addr, NULL, &hints, &res0);
2100 if (error)
2101 goto again;
2102 for (res = res0; res; res = res->ai_next) {
2103 /* cover it up */
2104 res->ai_flags = pai->ai_flags;
2105
2106 if (pai->ai_flags & AI_CANONNAME) {
2107 if (get_canonname(pai, res, cname) != 0) {
2108 freeaddrinfo(res0);
2109 goto again;
2110 }
2111 }
2112 }
2113 return res0;
2114 }
2115
2116 /*ARGSUSED*/
2117 static int
_files_getaddrinfo(void * rv,void * cb_data,va_list ap)2118 _files_getaddrinfo(void *rv, void *cb_data, va_list ap)
2119 {
2120 const char *name;
2121 const struct addrinfo *pai;
2122 struct addrinfo sentinel, *cur;
2123 struct addrinfo *p;
2124 FILE *hostf = NULL;
2125
2126 name = va_arg(ap, char *);
2127 pai = va_arg(ap, struct addrinfo *);
2128
2129 // fprintf(stderr, "_files_getaddrinfo() name = '%s'\n", name);
2130 memset(&sentinel, 0, sizeof(sentinel));
2131 cur = &sentinel;
2132
2133 _sethtent(&hostf);
2134 while ((p = _gethtent(&hostf, name, pai)) != NULL) {
2135 cur->ai_next = p;
2136 while (cur && cur->ai_next)
2137 cur = cur->ai_next;
2138 }
2139 _endhtent(&hostf);
2140
2141 *((struct addrinfo **)rv) = sentinel.ai_next;
2142 if (sentinel.ai_next == NULL)
2143 return NS_NOTFOUND;
2144 return NS_SUCCESS;
2145 }
2146
2147 /* resolver logic */
2148
2149 /*
2150 * Formulate a normal query, send, and await answer.
2151 * Returned answer is placed in supplied buffer "answer".
2152 * Perform preliminary check of answer, returning success only
2153 * if no error is indicated and the answer count is nonzero.
2154 * Return the size of the response on success, -1 on error.
2155 * Error number is left in h_errno.
2156 *
2157 * Caller must parse answer and determine whether it answers the question.
2158 */
2159 static int
res_queryN(const char * name,struct res_target * target,res_state res)2160 res_queryN(const char *name, /* domain name */ struct res_target *target,
2161 res_state res)
2162 {
2163 u_char buf[MAXPACKET];
2164 HEADER *hp;
2165 int n;
2166 struct res_target *t;
2167 int rcode;
2168 int ancount;
2169
2170 assert(name != NULL);
2171 /* XXX: target may be NULL??? */
2172
2173 rcode = NOERROR;
2174 ancount = 0;
2175
2176 for (t = target; t; t = t->next) {
2177 int class, type;
2178 u_char *answer;
2179 int anslen;
2180 u_int oflags;
2181
2182 hp = (HEADER *)(void *)t->answer;
2183 oflags = res->_flags;
2184
2185 again:
2186 hp->rcode = NOERROR; /* default */
2187
2188 /* make it easier... */
2189 class = t->qclass;
2190 type = t->qtype;
2191 answer = t->answer;
2192 anslen = t->anslen;
2193 #ifdef DEBUG
2194 if (res->options & RES_DEBUG)
2195 printf(";; res_nquery(%s, %d, %d)\n", name, class, type);
2196 #endif
2197
2198 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
2199 buf, sizeof(buf));
2200 #ifdef RES_USE_EDNS0
2201 if (n > 0 && (res->_flags & RES_F_EDNS0ERR) == 0 &&
2202 (res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0)
2203 n = res_nopt(res, n, buf, sizeof(buf), anslen);
2204 #endif
2205 if (n <= 0) {
2206 #ifdef DEBUG
2207 if (res->options & RES_DEBUG)
2208 printf(";; res_nquery: mkquery failed\n");
2209 #endif
2210 h_errno = NO_RECOVERY;
2211 return n;
2212 }
2213 n = res_nsend(res, buf, n, answer, anslen);
2214 #if 0
2215 if (n < 0) {
2216 #ifdef DEBUG
2217 if (res->options & RES_DEBUG)
2218 printf(";; res_query: send error\n");
2219 #endif
2220 h_errno = TRY_AGAIN;
2221 return n;
2222 }
2223 #endif
2224
2225 if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
2226 rcode = hp->rcode; /* record most recent error */
2227 #ifdef RES_USE_EDNS0
2228 /* if the query choked with EDNS0, retry without EDNS0 */
2229 if ((res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0 &&
2230 ((oflags ^ res->_flags) & RES_F_EDNS0ERR) != 0) {
2231 res->_flags |= RES_F_EDNS0ERR;
2232 #ifdef DEBUG
2233 if (res->options & RES_DEBUG)
2234 printf(";; res_nquery: retry without EDNS0\n");
2235 #endif
2236 goto again;
2237 }
2238 #endif
2239 #ifdef DEBUG
2240 if (res->options & RES_DEBUG)
2241 printf(";; rcode = %u, ancount=%u\n", hp->rcode,
2242 ntohs(hp->ancount));
2243 #endif
2244 continue;
2245 }
2246
2247 ancount += ntohs(hp->ancount);
2248
2249 t->n = n;
2250 }
2251
2252 if (ancount == 0) {
2253 switch (rcode) {
2254 case NXDOMAIN:
2255 h_errno = HOST_NOT_FOUND;
2256 break;
2257 case SERVFAIL:
2258 h_errno = TRY_AGAIN;
2259 break;
2260 case NOERROR:
2261 h_errno = NO_DATA;
2262 break;
2263 case FORMERR:
2264 case NOTIMP:
2265 case REFUSED:
2266 default:
2267 h_errno = NO_RECOVERY;
2268 break;
2269 }
2270 return -1;
2271 }
2272 return ancount;
2273 }
2274
2275 /*
2276 * Formulate a normal query, send, and retrieve answer in supplied buffer.
2277 * Return the size of the response on success, -1 on error.
2278 * If enabled, implement search rules until answer or unrecoverable failure
2279 * is detected. Error code, if any, is left in h_errno.
2280 */
2281 static int
res_searchN(const char * name,struct res_target * target,res_state res)2282 res_searchN(const char *name, struct res_target *target, res_state res)
2283 {
2284 const char *cp, * const *domain;
2285 HEADER *hp;
2286 u_int dots;
2287 int trailing_dot, ret, saved_herrno;
2288 int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
2289
2290 assert(name != NULL);
2291 assert(target != NULL);
2292
2293 hp = (HEADER *)(void *)target->answer; /*XXX*/
2294
2295 errno = 0;
2296 h_errno = HOST_NOT_FOUND; /* default, if we never query */
2297 dots = 0;
2298 for (cp = name; *cp; cp++)
2299 dots += (*cp == '.');
2300 trailing_dot = 0;
2301 if (cp > name && *--cp == '.')
2302 trailing_dot++;
2303
2304
2305 //fprintf(stderr, "res_searchN() name = '%s'\n", name);
2306
2307 /*
2308 * if there aren't any dots, it could be a user-level alias
2309 */
2310 if (!dots && (cp = __hostalias(name)) != NULL) {
2311 ret = res_queryN(cp, target, res);
2312 return ret;
2313 }
2314
2315 /*
2316 * If there are dots in the name already, let's just give it a try
2317 * 'as is'. The threshold can be set with the "ndots" option.
2318 */
2319 saved_herrno = -1;
2320 if (dots >= res->ndots) {
2321 ret = res_querydomainN(name, NULL, target, res);
2322 if (ret > 0)
2323 return (ret);
2324 saved_herrno = h_errno;
2325 tried_as_is++;
2326 }
2327
2328 /*
2329 * We do at least one level of search if
2330 * - there is no dot and RES_DEFNAME is set, or
2331 * - there is at least one dot, there is no trailing dot,
2332 * and RES_DNSRCH is set.
2333 */
2334 if ((!dots && (res->options & RES_DEFNAMES)) ||
2335 (dots && !trailing_dot && (res->options & RES_DNSRCH))) {
2336 int done = 0;
2337
2338 /* Unfortunately we need to set stuff up before
2339 * the domain stuff is tried. Will have a better
2340 * fix after thread pools are used.
2341 */
2342 _resolv_populate_res_for_net(res);
2343
2344 for (domain = (const char * const *)res->dnsrch;
2345 *domain && !done;
2346 domain++) {
2347
2348 ret = res_querydomainN(name, *domain, target, res);
2349 if (ret > 0)
2350 return ret;
2351
2352 /*
2353 * If no server present, give up.
2354 * If name isn't found in this domain,
2355 * keep trying higher domains in the search list
2356 * (if that's enabled).
2357 * On a NO_DATA error, keep trying, otherwise
2358 * a wildcard entry of another type could keep us
2359 * from finding this entry higher in the domain.
2360 * If we get some other error (negative answer or
2361 * server failure), then stop searching up,
2362 * but try the input name below in case it's
2363 * fully-qualified.
2364 */
2365 if (errno == ECONNREFUSED) {
2366 h_errno = TRY_AGAIN;
2367 return -1;
2368 }
2369
2370 switch (h_errno) {
2371 case NO_DATA:
2372 got_nodata++;
2373 /* FALLTHROUGH */
2374 case HOST_NOT_FOUND:
2375 /* keep trying */
2376 break;
2377 case TRY_AGAIN:
2378 if (hp->rcode == SERVFAIL) {
2379 /* try next search element, if any */
2380 got_servfail++;
2381 break;
2382 }
2383 /* FALLTHROUGH */
2384 default:
2385 /* anything else implies that we're done */
2386 done++;
2387 }
2388 /*
2389 * if we got here for some reason other than DNSRCH,
2390 * we only wanted one iteration of the loop, so stop.
2391 */
2392 if (!(res->options & RES_DNSRCH))
2393 done++;
2394 }
2395 }
2396
2397 /*
2398 * if we have not already tried the name "as is", do that now.
2399 * note that we do this regardless of how many dots were in the
2400 * name or whether it ends with a dot.
2401 */
2402 if (!tried_as_is) {
2403 ret = res_querydomainN(name, NULL, target, res);
2404 if (ret > 0)
2405 return ret;
2406 }
2407
2408 /*
2409 * if we got here, we didn't satisfy the search.
2410 * if we did an initial full query, return that query's h_errno
2411 * (note that we wouldn't be here if that query had succeeded).
2412 * else if we ever got a nodata, send that back as the reason.
2413 * else send back meaningless h_errno, that being the one from
2414 * the last DNSRCH we did.
2415 */
2416 if (saved_herrno != -1)
2417 h_errno = saved_herrno;
2418 else if (got_nodata)
2419 h_errno = NO_DATA;
2420 else if (got_servfail)
2421 h_errno = TRY_AGAIN;
2422 return -1;
2423 }
2424
2425 /*
2426 * Perform a call on res_query on the concatenation of name and domain,
2427 * removing a trailing dot from name if domain is NULL.
2428 */
2429 static int
res_querydomainN(const char * name,const char * domain,struct res_target * target,res_state res)2430 res_querydomainN(const char *name, const char *domain,
2431 struct res_target *target, res_state res)
2432 {
2433 char nbuf[MAXDNAME];
2434 const char *longname = nbuf;
2435 size_t n, d;
2436
2437 assert(name != NULL);
2438 /* XXX: target may be NULL??? */
2439
2440 #ifdef DEBUG
2441 if (res->options & RES_DEBUG)
2442 printf(";; res_querydomain(%s, %s)\n",
2443 name, domain?domain:"<Nil>");
2444 #endif
2445 if (domain == NULL) {
2446 /*
2447 * Check for trailing '.';
2448 * copy without '.' if present.
2449 */
2450 n = strlen(name);
2451 if (n + 1 > sizeof(nbuf)) {
2452 h_errno = NO_RECOVERY;
2453 return -1;
2454 }
2455 if (n > 0 && name[--n] == '.') {
2456 strncpy(nbuf, name, n);
2457 nbuf[n] = '\0';
2458 } else
2459 longname = name;
2460 } else {
2461 n = strlen(name);
2462 d = strlen(domain);
2463 if (n + 1 + d + 1 > sizeof(nbuf)) {
2464 h_errno = NO_RECOVERY;
2465 return -1;
2466 }
2467 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
2468 }
2469 return res_queryN(longname, target, res);
2470 }
2471