1 /* $NetBSD: res_send.c,v 1.9 2006/01/24 17:41:25 christos Exp $ */ 2 3 /* 4 * Copyright 2008 Android Open Source Project (source port randomization) 5 * Copyright (c) 1985, 1989, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 /* 38 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 39 * 40 * Permission to use, copy, modify, and distribute this software for any 41 * purpose with or without fee is hereby granted, provided that the above 42 * copyright notice and this permission notice appear in all copies, and that 43 * the name of Digital Equipment Corporation not be used in advertising or 44 * publicity pertaining to distribution of the document or software without 45 * specific, written prior permission. 46 * 47 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 48 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 49 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 50 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 51 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 52 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 53 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 54 * SOFTWARE. 55 */ 56 57 /* 58 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 59 * Portions Copyright (c) 1996-1999 by Internet Software Consortium. 60 * 61 * Permission to use, copy, modify, and distribute this software for any 62 * purpose with or without fee is hereby granted, provided that the above 63 * copyright notice and this permission notice appear in all copies. 64 * 65 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 66 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 67 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 68 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 69 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 70 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 71 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 72 */ 73 74 #include <sys/cdefs.h> 75 #if defined(LIBC_SCCS) && !defined(lint) 76 #ifdef notdef 77 static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; 78 static const char rcsid[] = "Id: res_send.c,v 1.5.2.2.4.5 2004/08/10 02:19:56 marka Exp"; 79 #else 80 __RCSID("$NetBSD: res_send.c,v 1.9 2006/01/24 17:41:25 christos Exp $"); 81 #endif 82 #endif /* LIBC_SCCS and not lint */ 83 84 /* set to 1 to use our small/simple/limited DNS cache */ 85 #define USE_RESOLV_CACHE 1 86 87 /* 88 * Send query to name server and wait for reply. 89 */ 90 91 #include <sys/types.h> 92 #include <sys/param.h> 93 #include <sys/time.h> 94 #include <sys/socket.h> 95 #include <sys/uio.h> 96 97 #include <netinet/in.h> 98 #include "arpa_nameser.h" 99 #include <arpa/inet.h> 100 101 #include <errno.h> 102 #include <fcntl.h> 103 #include <netdb.h> 104 #ifdef ANDROID_CHANGES 105 #include "resolv_private.h" 106 #else 107 #include <resolv.h> 108 #endif 109 #include <signal.h> 110 #include <stdio.h> 111 #include <stdlib.h> 112 #include <string.h> 113 #include <time.h> 114 #include <unistd.h> 115 116 #include <isc/eventlib.h> 117 118 #if USE_RESOLV_CACHE 119 # include <resolv_cache.h> 120 #endif 121 122 #include "libc_logging.h" 123 124 #ifndef DE_CONST 125 #define DE_CONST(c,v) v = ((c) ? \ 126 strchr((const void *)(c), *(const char *)(const void *)(c)) : NULL) 127 #endif 128 129 /* Options. Leave them on. */ 130 #ifndef DEBUG 131 #define DEBUG 132 #endif 133 #include "res_debug.h" 134 #include "res_private.h" 135 136 #define EXT(res) ((res)->_u._ext) 137 #define DBG 0 138 139 static const int highestFD = FD_SETSIZE - 1; 140 141 /* Forward. */ 142 143 static int get_salen __P((const struct sockaddr *)); 144 static struct sockaddr * get_nsaddr __P((res_state, size_t)); 145 static int send_vc(res_state, const u_char *, int, 146 u_char *, int, int *, int); 147 static int send_dg(res_state, const u_char *, int, 148 u_char *, int, int *, int, 149 int *, int *); 150 static void Aerror(const res_state, FILE *, const char *, int, 151 const struct sockaddr *, int); 152 static void Perror(const res_state, FILE *, const char *, int); 153 static int sock_eq(struct sockaddr *, struct sockaddr *); 154 #ifdef NEED_PSELECT 155 static int pselect(int, void *, void *, void *, 156 struct timespec *, 157 const sigset_t *); 158 #endif 159 void res_pquery(const res_state, const u_char *, int, FILE *); 160 static int connect_with_timeout(int sock, const struct sockaddr *nsap, 161 socklen_t salen, int sec); 162 static int retrying_select(const int sock, fd_set *readset, fd_set *writeset, 163 const struct timespec *finish); 164 165 /* BIONIC-BEGIN: implement source port randomization */ 166 typedef union { 167 struct sockaddr sa; 168 struct sockaddr_in sin; 169 struct sockaddr_in6 sin6; 170 } _sockaddr_union; 171 172 static int 173 random_bind( int s, int family ) 174 { 175 _sockaddr_union u; 176 int j; 177 socklen_t slen; 178 179 /* clear all, this also sets the IP4/6 address to 'any' */ 180 memset( &u, 0, sizeof u ); 181 182 switch (family) { 183 case AF_INET: 184 u.sin.sin_family = family; 185 slen = sizeof u.sin; 186 break; 187 case AF_INET6: 188 u.sin6.sin6_family = family; 189 slen = sizeof u.sin6; 190 break; 191 default: 192 errno = EPROTO; 193 return -1; 194 } 195 196 /* first try to bind to a random source port a few times */ 197 for (j = 0; j < 10; j++) { 198 /* find a random port between 1025 .. 65534 */ 199 int port = 1025 + (res_randomid() % (65535-1025)); 200 if (family == AF_INET) 201 u.sin.sin_port = htons(port); 202 else 203 u.sin6.sin6_port = htons(port); 204 205 if ( !bind( s, &u.sa, slen ) ) 206 return 0; 207 } 208 209 /* nothing after 10 tries, our network table is probably busy */ 210 /* let the system decide which port is best */ 211 if (family == AF_INET) 212 u.sin.sin_port = 0; 213 else 214 u.sin6.sin6_port = 0; 215 216 return bind( s, &u.sa, slen ); 217 } 218 /* BIONIC-END */ 219 220 static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; 221 222 /* Public. */ 223 224 /* int 225 * res_isourserver(ina) 226 * looks up "ina" in _res.ns_addr_list[] 227 * returns: 228 * 0 : not found 229 * >0 : found 230 * author: 231 * paul vixie, 29may94 232 */ 233 __LIBC_HIDDEN__ int 234 res_ourserver_p(const res_state statp, const struct sockaddr *sa) { 235 const struct sockaddr_in *inp, *srv; 236 const struct sockaddr_in6 *in6p, *srv6; 237 int ns; 238 239 switch (sa->sa_family) { 240 case AF_INET: 241 inp = (const struct sockaddr_in *)(const void *)sa; 242 for (ns = 0; ns < statp->nscount; ns++) { 243 srv = (struct sockaddr_in *)(void *)get_nsaddr(statp, (size_t)ns); 244 if (srv->sin_family == inp->sin_family && 245 srv->sin_port == inp->sin_port && 246 (srv->sin_addr.s_addr == INADDR_ANY || 247 srv->sin_addr.s_addr == inp->sin_addr.s_addr)) 248 return (1); 249 } 250 break; 251 case AF_INET6: 252 if (EXT(statp).ext == NULL) 253 break; 254 in6p = (const struct sockaddr_in6 *)(const void *)sa; 255 for (ns = 0; ns < statp->nscount; ns++) { 256 srv6 = (struct sockaddr_in6 *)(void *)get_nsaddr(statp, (size_t)ns); 257 if (srv6->sin6_family == in6p->sin6_family && 258 srv6->sin6_port == in6p->sin6_port && 259 #ifdef HAVE_SIN6_SCOPE_ID 260 (srv6->sin6_scope_id == 0 || 261 srv6->sin6_scope_id == in6p->sin6_scope_id) && 262 #endif 263 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) || 264 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr))) 265 return (1); 266 } 267 break; 268 default: 269 break; 270 } 271 return (0); 272 } 273 274 /* int 275 * res_nameinquery(name, type, class, buf, eom) 276 * look for (name,type,class) in the query section of packet (buf,eom) 277 * requires: 278 * buf + HFIXEDSZ <= eom 279 * returns: 280 * -1 : format error 281 * 0 : not found 282 * >0 : found 283 * author: 284 * paul vixie, 29may94 285 */ 286 int 287 res_nameinquery(const char *name, int type, int class, 288 const u_char *buf, const u_char *eom) 289 { 290 const u_char *cp = buf + HFIXEDSZ; 291 int qdcount = ntohs(((const HEADER*)(const void *)buf)->qdcount); 292 293 while (qdcount-- > 0) { 294 char tname[MAXDNAME+1]; 295 int n, ttype, tclass; 296 297 n = dn_expand(buf, eom, cp, tname, sizeof tname); 298 if (n < 0) 299 return (-1); 300 cp += n; 301 if (cp + 2 * INT16SZ > eom) 302 return (-1); 303 ttype = ns_get16(cp); cp += INT16SZ; 304 tclass = ns_get16(cp); cp += INT16SZ; 305 if (ttype == type && tclass == class && 306 ns_samename(tname, name) == 1) 307 return (1); 308 } 309 return (0); 310 } 311 312 /* int 313 * res_queriesmatch(buf1, eom1, buf2, eom2) 314 * is there a 1:1 mapping of (name,type,class) 315 * in (buf1,eom1) and (buf2,eom2)? 316 * returns: 317 * -1 : format error 318 * 0 : not a 1:1 mapping 319 * >0 : is a 1:1 mapping 320 * author: 321 * paul vixie, 29may94 322 */ 323 int 324 res_queriesmatch(const u_char *buf1, const u_char *eom1, 325 const u_char *buf2, const u_char *eom2) 326 { 327 const u_char *cp = buf1 + HFIXEDSZ; 328 int qdcount = ntohs(((const HEADER*)(const void *)buf1)->qdcount); 329 330 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2) 331 return (-1); 332 333 /* 334 * Only header section present in replies to 335 * dynamic update packets. 336 */ 337 if ((((const HEADER *)(const void *)buf1)->opcode == ns_o_update) && 338 (((const HEADER *)(const void *)buf2)->opcode == ns_o_update)) 339 return (1); 340 341 if (qdcount != ntohs(((const HEADER*)(const void *)buf2)->qdcount)) 342 return (0); 343 while (qdcount-- > 0) { 344 char tname[MAXDNAME+1]; 345 int n, ttype, tclass; 346 347 n = dn_expand(buf1, eom1, cp, tname, sizeof tname); 348 if (n < 0) 349 return (-1); 350 cp += n; 351 if (cp + 2 * INT16SZ > eom1) 352 return (-1); 353 ttype = ns_get16(cp); cp += INT16SZ; 354 tclass = ns_get16(cp); cp += INT16SZ; 355 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) 356 return (0); 357 } 358 return (1); 359 } 360 361 362 int 363 res_nsend(res_state statp, 364 const u_char *buf, int buflen, u_char *ans, int anssiz) 365 { 366 int gotsomewhere, terrno, try, v_circuit, resplen, ns, n; 367 char abuf[NI_MAXHOST]; 368 #if USE_RESOLV_CACHE 369 struct resolv_cache* cache; 370 ResolvCacheStatus cache_status = RESOLV_CACHE_UNSUPPORTED; 371 #endif 372 373 #if !USE_RESOLV_CACHE 374 if (statp->nscount == 0) { 375 errno = ESRCH; 376 return (-1); 377 } 378 #endif 379 380 if (anssiz < HFIXEDSZ) { 381 errno = EINVAL; 382 return (-1); 383 } 384 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY), 385 (stdout, ";; res_send()\n"), buf, buflen); 386 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ; 387 gotsomewhere = 0; 388 terrno = ETIMEDOUT; 389 390 #if USE_RESOLV_CACHE 391 // get the cache associated with the interface 392 cache = __get_res_cache(statp->iface); 393 if (cache != NULL) { 394 int anslen = 0; 395 cache_status = _resolv_cache_lookup( 396 cache, buf, buflen, 397 ans, anssiz, &anslen); 398 399 if (cache_status == RESOLV_CACHE_FOUND) { 400 return anslen; 401 } else { 402 // had a cache miss for a known interface, so populate the thread private 403 // data so the normal resolve path can do its thing 404 _resolv_populate_res_for_iface(statp); 405 } 406 } 407 408 if (statp->nscount == 0) { 409 errno = ESRCH; 410 return (-1); 411 } 412 #endif 413 414 /* 415 * If the ns_addr_list in the resolver context has changed, then 416 * invalidate our cached copy and the associated timing data. 417 */ 418 if (EXT(statp).nscount != 0) { 419 int needclose = 0; 420 struct sockaddr_storage peer; 421 socklen_t peerlen; 422 423 if (EXT(statp).nscount != statp->nscount) 424 needclose++; 425 else 426 for (ns = 0; ns < statp->nscount; ns++) { 427 if (statp->nsaddr_list[ns].sin_family && 428 !sock_eq((struct sockaddr *)(void *)&statp->nsaddr_list[ns], 429 (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[ns])) { 430 needclose++; 431 break; 432 } 433 434 if (EXT(statp).nssocks[ns] == -1) 435 continue; 436 peerlen = sizeof(peer); 437 if (getpeername(EXT(statp).nssocks[ns], 438 (struct sockaddr *)(void *)&peer, &peerlen) < 0) { 439 needclose++; 440 break; 441 } 442 if (!sock_eq((struct sockaddr *)(void *)&peer, 443 get_nsaddr(statp, (size_t)ns))) { 444 needclose++; 445 break; 446 } 447 } 448 if (needclose) { 449 res_nclose(statp); 450 EXT(statp).nscount = 0; 451 } 452 } 453 454 /* 455 * Maybe initialize our private copy of the ns_addr_list. 456 */ 457 if (EXT(statp).nscount == 0) { 458 for (ns = 0; ns < statp->nscount; ns++) { 459 EXT(statp).nstimes[ns] = RES_MAXTIME; 460 EXT(statp).nssocks[ns] = -1; 461 if (!statp->nsaddr_list[ns].sin_family) 462 continue; 463 EXT(statp).ext->nsaddrs[ns].sin = 464 statp->nsaddr_list[ns]; 465 } 466 EXT(statp).nscount = statp->nscount; 467 } 468 469 /* 470 * Some resolvers want to even out the load on their nameservers. 471 * Note that RES_BLAST overrides RES_ROTATE. 472 */ 473 if ((statp->options & RES_ROTATE) != 0U && 474 (statp->options & RES_BLAST) == 0U) { 475 union res_sockaddr_union inu; 476 struct sockaddr_in ina; 477 int lastns = statp->nscount - 1; 478 int fd; 479 u_int16_t nstime; 480 481 if (EXT(statp).ext != NULL) 482 inu = EXT(statp).ext->nsaddrs[0]; 483 ina = statp->nsaddr_list[0]; 484 fd = EXT(statp).nssocks[0]; 485 nstime = EXT(statp).nstimes[0]; 486 for (ns = 0; ns < lastns; ns++) { 487 if (EXT(statp).ext != NULL) 488 EXT(statp).ext->nsaddrs[ns] = 489 EXT(statp).ext->nsaddrs[ns + 1]; 490 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1]; 491 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1]; 492 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1]; 493 } 494 if (EXT(statp).ext != NULL) 495 EXT(statp).ext->nsaddrs[lastns] = inu; 496 statp->nsaddr_list[lastns] = ina; 497 EXT(statp).nssocks[lastns] = fd; 498 EXT(statp).nstimes[lastns] = nstime; 499 } 500 501 /* 502 * Send request, RETRY times, or until successful. 503 */ 504 for (try = 0; try < statp->retry; try++) { 505 for (ns = 0; ns < statp->nscount; ns++) { 506 struct sockaddr *nsap; 507 int nsaplen; 508 nsap = get_nsaddr(statp, (size_t)ns); 509 nsaplen = get_salen(nsap); 510 statp->_flags &= ~RES_F_LASTMASK; 511 statp->_flags |= (ns << RES_F_LASTSHIFT); 512 same_ns: 513 if (statp->qhook) { 514 int done = 0, loops = 0; 515 516 do { 517 res_sendhookact act; 518 519 act = (*statp->qhook)(&nsap, &buf, &buflen, 520 ans, anssiz, &resplen); 521 switch (act) { 522 case res_goahead: 523 done = 1; 524 break; 525 case res_nextns: 526 res_nclose(statp); 527 goto next_ns; 528 case res_done: 529 return (resplen); 530 case res_modified: 531 /* give the hook another try */ 532 if (++loops < 42) /*doug adams*/ 533 break; 534 /*FALLTHROUGH*/ 535 case res_error: 536 /*FALLTHROUGH*/ 537 default: 538 goto fail; 539 } 540 } while (!done); 541 } 542 543 Dprint(((statp->options & RES_DEBUG) && 544 getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf), 545 NULL, 0, niflags) == 0), 546 (stdout, ";; Querying server (# %d) address = %s\n", 547 ns + 1, abuf)); 548 549 550 if (v_circuit) { 551 /* Use VC; at most one attempt per server. */ 552 try = statp->retry; 553 554 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, 555 ns); 556 557 if (DBG) { 558 __libc_format_log(ANDROID_LOG_DEBUG, "libc", 559 "used send_vc %d\n", n); 560 } 561 562 if (n < 0) 563 goto fail; 564 if (n == 0) 565 goto next_ns; 566 resplen = n; 567 } else { 568 /* Use datagrams. */ 569 if (DBG) { 570 __libc_format_log(ANDROID_LOG_DEBUG, "libc", "using send_dg\n"); 571 } 572 573 n = send_dg(statp, buf, buflen, ans, anssiz, &terrno, 574 ns, &v_circuit, &gotsomewhere); 575 if (DBG) { 576 __libc_format_log(ANDROID_LOG_DEBUG, "libc", "used send_dg %d\n",n); 577 } 578 579 if (n < 0) 580 goto fail; 581 if (n == 0) 582 goto next_ns; 583 if (DBG) { 584 __libc_format_log(ANDROID_LOG_DEBUG, "libc", 585 "time=%d, %d\n",time(NULL), time(NULL)%2); 586 } 587 if (v_circuit) 588 goto same_ns; 589 resplen = n; 590 } 591 592 Dprint((statp->options & RES_DEBUG) || 593 ((statp->pfcode & RES_PRF_REPLY) && 594 (statp->pfcode & RES_PRF_HEAD1)), 595 (stdout, ";; got answer:\n")); 596 597 DprintQ((statp->options & RES_DEBUG) || 598 (statp->pfcode & RES_PRF_REPLY), 599 (stdout, "%s", ""), 600 ans, (resplen > anssiz) ? anssiz : resplen); 601 602 #if USE_RESOLV_CACHE 603 if (cache_status == RESOLV_CACHE_NOTFOUND) { 604 _resolv_cache_add(cache, buf, buflen, 605 ans, resplen); 606 } 607 #endif 608 /* 609 * If we have temporarily opened a virtual circuit, 610 * or if we haven't been asked to keep a socket open, 611 * close the socket. 612 */ 613 if ((v_circuit && (statp->options & RES_USEVC) == 0U) || 614 (statp->options & RES_STAYOPEN) == 0U) { 615 res_nclose(statp); 616 } 617 if (statp->rhook) { 618 int done = 0, loops = 0; 619 620 do { 621 res_sendhookact act; 622 623 act = (*statp->rhook)(nsap, buf, buflen, 624 ans, anssiz, &resplen); 625 switch (act) { 626 case res_goahead: 627 case res_done: 628 done = 1; 629 break; 630 case res_nextns: 631 res_nclose(statp); 632 goto next_ns; 633 case res_modified: 634 /* give the hook another try */ 635 if (++loops < 42) /*doug adams*/ 636 break; 637 /*FALLTHROUGH*/ 638 case res_error: 639 /*FALLTHROUGH*/ 640 default: 641 goto fail; 642 } 643 } while (!done); 644 645 } 646 return (resplen); 647 next_ns: ; 648 } /*foreach ns*/ 649 } /*foreach retry*/ 650 res_nclose(statp); 651 if (!v_circuit) { 652 if (!gotsomewhere) 653 errno = ECONNREFUSED; /* no nameservers found */ 654 else 655 errno = ETIMEDOUT; /* no answer obtained */ 656 } else 657 errno = terrno; 658 659 #if USE_RESOLV_CACHE 660 _resolv_cache_query_failed(cache, buf, buflen); 661 #endif 662 663 return (-1); 664 fail: 665 #if USE_RESOLV_CACHE 666 _resolv_cache_query_failed(cache, buf, buflen); 667 #endif 668 res_nclose(statp); 669 return (-1); 670 } 671 672 /* Private */ 673 674 static int 675 get_salen(sa) 676 const struct sockaddr *sa; 677 { 678 679 #ifdef HAVE_SA_LEN 680 /* There are people do not set sa_len. Be forgiving to them. */ 681 if (sa->sa_len) 682 return (sa->sa_len); 683 #endif 684 685 if (sa->sa_family == AF_INET) 686 return (sizeof(struct sockaddr_in)); 687 else if (sa->sa_family == AF_INET6) 688 return (sizeof(struct sockaddr_in6)); 689 else 690 return (0); /* unknown, die on connect */ 691 } 692 693 /* 694 * pick appropriate nsaddr_list for use. see res_init() for initialization. 695 */ 696 static struct sockaddr * 697 get_nsaddr(statp, n) 698 res_state statp; 699 size_t n; 700 { 701 702 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) { 703 /* 704 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger 705 * than struct sockaddr, and 706 * - user code did not update statp->nsaddr_list[n]. 707 */ 708 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n]; 709 } else { 710 /* 711 * - user code updated statp->nsaddr_list[n], or 712 * - statp->nsaddr_list[n] has the same content as 713 * EXT(statp).ext->nsaddrs[n]. 714 */ 715 return (struct sockaddr *)(void *)&statp->nsaddr_list[n]; 716 } 717 } 718 719 static int get_timeout(const res_state statp, const int ns) 720 { 721 int timeout = (statp->retrans << ns); 722 if (ns > 0) { 723 timeout /= statp->nscount; 724 } 725 if (timeout <= 0) { 726 timeout = 1; 727 } 728 if (DBG) { 729 __libc_format_log(ANDROID_LOG_DEBUG, "libc", "using timeout of %d sec\n", timeout); 730 } 731 732 return timeout; 733 } 734 735 static int 736 send_vc(res_state statp, 737 const u_char *buf, int buflen, u_char *ans, int anssiz, 738 int *terrno, int ns) 739 { 740 const HEADER *hp = (const HEADER *)(const void *)buf; 741 HEADER *anhp = (HEADER *)(void *)ans; 742 struct sockaddr *nsap; 743 int nsaplen; 744 int truncating, connreset, resplen, n; 745 struct iovec iov[2]; 746 u_short len; 747 u_char *cp; 748 void *tmp; 749 750 if (DBG) { 751 __libc_format_log(ANDROID_LOG_DEBUG, "libc", "using send_vc\n"); 752 } 753 754 nsap = get_nsaddr(statp, (size_t)ns); 755 nsaplen = get_salen(nsap); 756 757 connreset = 0; 758 same_ns: 759 truncating = 0; 760 761 /* Are we still talking to whom we want to talk to? */ 762 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { 763 struct sockaddr_storage peer; 764 socklen_t size = sizeof peer; 765 766 if (getpeername(statp->_vcsock, 767 (struct sockaddr *)(void *)&peer, &size) < 0 || 768 !sock_eq((struct sockaddr *)(void *)&peer, nsap)) { 769 res_nclose(statp); 770 statp->_flags &= ~RES_F_VC; 771 } 772 } 773 774 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) { 775 if (statp->_vcsock >= 0) 776 res_nclose(statp); 777 778 statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0); 779 if (statp->_vcsock > highestFD) { 780 res_nclose(statp); 781 errno = ENOTSOCK; 782 } 783 if (statp->_vcsock < 0) { 784 switch (errno) { 785 case EPROTONOSUPPORT: 786 #ifdef EPFNOSUPPORT 787 case EPFNOSUPPORT: 788 #endif 789 case EAFNOSUPPORT: 790 Perror(statp, stderr, "socket(vc)", errno); 791 return (0); 792 default: 793 *terrno = errno; 794 Perror(statp, stderr, "socket(vc)", errno); 795 return (-1); 796 } 797 } 798 errno = 0; 799 if (random_bind(statp->_vcsock,nsap->sa_family) < 0) { 800 *terrno = errno; 801 Aerror(statp, stderr, "bind/vc", errno, nsap, 802 nsaplen); 803 res_nclose(statp); 804 return (0); 805 } 806 if (connect_with_timeout(statp->_vcsock, nsap, (socklen_t)nsaplen, 807 get_timeout(statp, ns)) < 0) { 808 *terrno = errno; 809 Aerror(statp, stderr, "connect/vc", errno, nsap, 810 nsaplen); 811 res_nclose(statp); 812 return (0); 813 } 814 statp->_flags |= RES_F_VC; 815 } 816 817 /* 818 * Send length & message 819 */ 820 ns_put16((u_short)buflen, (u_char*)(void *)&len); 821 iov[0] = evConsIovec(&len, INT16SZ); 822 DE_CONST(buf, tmp); 823 iov[1] = evConsIovec(tmp, (size_t)buflen); 824 if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { 825 *terrno = errno; 826 Perror(statp, stderr, "write failed", errno); 827 res_nclose(statp); 828 return (0); 829 } 830 /* 831 * Receive length & response 832 */ 833 read_len: 834 cp = ans; 835 len = INT16SZ; 836 while ((n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0) { 837 cp += n; 838 if ((len -= n) == 0) 839 break; 840 } 841 if (n <= 0) { 842 *terrno = errno; 843 Perror(statp, stderr, "read failed", errno); 844 res_nclose(statp); 845 /* 846 * A long running process might get its TCP 847 * connection reset if the remote server was 848 * restarted. Requery the server instead of 849 * trying a new one. When there is only one 850 * server, this means that a query might work 851 * instead of failing. We only allow one reset 852 * per query to prevent looping. 853 */ 854 if (*terrno == ECONNRESET && !connreset) { 855 connreset = 1; 856 res_nclose(statp); 857 goto same_ns; 858 } 859 res_nclose(statp); 860 return (0); 861 } 862 resplen = ns_get16(ans); 863 if (resplen > anssiz) { 864 Dprint(statp->options & RES_DEBUG, 865 (stdout, ";; response truncated\n") 866 ); 867 truncating = 1; 868 len = anssiz; 869 } else 870 len = resplen; 871 if (len < HFIXEDSZ) { 872 /* 873 * Undersized message. 874 */ 875 Dprint(statp->options & RES_DEBUG, 876 (stdout, ";; undersized: %d\n", len)); 877 *terrno = EMSGSIZE; 878 res_nclose(statp); 879 return (0); 880 } 881 cp = ans; 882 while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0){ 883 cp += n; 884 len -= n; 885 } 886 if (n <= 0) { 887 *terrno = errno; 888 Perror(statp, stderr, "read(vc)", errno); 889 res_nclose(statp); 890 return (0); 891 } 892 if (truncating) { 893 /* 894 * Flush rest of answer so connection stays in synch. 895 */ 896 anhp->tc = 1; 897 len = resplen - anssiz; 898 while (len != 0) { 899 char junk[PACKETSZ]; 900 901 n = read(statp->_vcsock, junk, 902 (len > sizeof junk) ? sizeof junk : len); 903 if (n > 0) 904 len -= n; 905 else 906 break; 907 } 908 } 909 /* 910 * If the calling applicating has bailed out of 911 * a previous call and failed to arrange to have 912 * the circuit closed or the server has got 913 * itself confused, then drop the packet and 914 * wait for the correct one. 915 */ 916 if (hp->id != anhp->id) { 917 DprintQ((statp->options & RES_DEBUG) || 918 (statp->pfcode & RES_PRF_REPLY), 919 (stdout, ";; old answer (unexpected):\n"), 920 ans, (resplen > anssiz) ? anssiz: resplen); 921 goto read_len; 922 } 923 924 /* 925 * All is well, or the error is fatal. Signal that the 926 * next nameserver ought not be tried. 927 */ 928 return (resplen); 929 } 930 931 /* return -1 on error (errno set), 0 on success */ 932 static int 933 connect_with_timeout(int sock, const struct sockaddr *nsap, socklen_t salen, int sec) 934 { 935 int res, origflags; 936 fd_set rset, wset; 937 struct timespec now, timeout, finish; 938 939 origflags = fcntl(sock, F_GETFL, 0); 940 fcntl(sock, F_SETFL, origflags | O_NONBLOCK); 941 942 res = connect(sock, nsap, salen); 943 if (res < 0 && errno != EINPROGRESS) { 944 res = -1; 945 goto done; 946 } 947 if (res != 0) { 948 now = evNowTime(); 949 timeout = evConsTime((long)sec, 0L); 950 finish = evAddTime(now, timeout); 951 if (DBG) { 952 __libc_format_log(ANDROID_LOG_DEBUG, "libc", " %d send_vc\n", sock); 953 } 954 955 res = retrying_select(sock, &rset, &wset, &finish); 956 if (res <= 0) { 957 res = -1; 958 } 959 } 960 done: 961 fcntl(sock, F_SETFL, origflags); 962 if (DBG) { 963 __libc_format_log(ANDROID_LOG_DEBUG, "libc", 964 " %d connect_with_timeout returning %s\n", sock, res); 965 } 966 return res; 967 } 968 969 static int 970 retrying_select(const int sock, fd_set *readset, fd_set *writeset, const struct timespec *finish) 971 { 972 struct timespec now, timeout; 973 int n, error; 974 socklen_t len; 975 976 977 retry: 978 if (DBG) { 979 __libc_format_log(ANDROID_LOG_DEBUG, "libc", " %d retying_select\n", sock); 980 } 981 982 now = evNowTime(); 983 if (readset) { 984 FD_ZERO(readset); 985 FD_SET(sock, readset); 986 } 987 if (writeset) { 988 FD_ZERO(writeset); 989 FD_SET(sock, writeset); 990 } 991 if (evCmpTime(*finish, now) > 0) 992 timeout = evSubTime(*finish, now); 993 else 994 timeout = evConsTime(0L, 0L); 995 996 n = pselect(sock + 1, readset, writeset, NULL, &timeout, NULL); 997 if (n == 0) { 998 if (DBG) { 999 __libc_format_log(ANDROID_LOG_DEBUG, " libc", 1000 " %d retrying_select timeout\n", sock); 1001 } 1002 errno = ETIMEDOUT; 1003 return 0; 1004 } 1005 if (n < 0) { 1006 if (errno == EINTR) 1007 goto retry; 1008 if (DBG) { 1009 __libc_format_log(ANDROID_LOG_DEBUG, "libc", 1010 " %d retrying_select got error %d\n",sock, n); 1011 } 1012 return n; 1013 } 1014 if ((readset && FD_ISSET(sock, readset)) || (writeset && FD_ISSET(sock, writeset))) { 1015 len = sizeof(error); 1016 if (getsockopt(sock, SOL_SOCKET, SO_ERROR, &error, &len) < 0 || error) { 1017 errno = error; 1018 if (DBG) { 1019 __libc_format_log(ANDROID_LOG_DEBUG, "libc", 1020 " %d retrying_select dot error2 %d\n", sock, errno); 1021 } 1022 1023 return -1; 1024 } 1025 } 1026 if (DBG) { 1027 __libc_format_log(ANDROID_LOG_DEBUG, "libc", 1028 " %d retrying_select returning %d for %d\n",sock, n); 1029 } 1030 1031 return n; 1032 } 1033 1034 1035 static int 1036 send_dg(res_state statp, 1037 const u_char *buf, int buflen, u_char *ans, int anssiz, 1038 int *terrno, int ns, int *v_circuit, int *gotsomewhere) 1039 { 1040 const HEADER *hp = (const HEADER *)(const void *)buf; 1041 HEADER *anhp = (HEADER *)(void *)ans; 1042 const struct sockaddr *nsap; 1043 int nsaplen; 1044 struct timespec now, timeout, finish; 1045 fd_set dsmask; 1046 struct sockaddr_storage from; 1047 socklen_t fromlen; 1048 int resplen, seconds, n, s; 1049 1050 nsap = get_nsaddr(statp, (size_t)ns); 1051 nsaplen = get_salen(nsap); 1052 if (EXT(statp).nssocks[ns] == -1) { 1053 EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0); 1054 if (EXT(statp).nssocks[ns] > highestFD) { 1055 res_nclose(statp); 1056 errno = ENOTSOCK; 1057 } 1058 if (EXT(statp).nssocks[ns] < 0) { 1059 switch (errno) { 1060 case EPROTONOSUPPORT: 1061 #ifdef EPFNOSUPPORT 1062 case EPFNOSUPPORT: 1063 #endif 1064 case EAFNOSUPPORT: 1065 Perror(statp, stderr, "socket(dg)", errno); 1066 return (0); 1067 default: 1068 *terrno = errno; 1069 Perror(statp, stderr, "socket(dg)", errno); 1070 return (-1); 1071 } 1072 } 1073 #ifndef CANNOT_CONNECT_DGRAM 1074 /* 1075 * On a 4.3BSD+ machine (client and server, 1076 * actually), sending to a nameserver datagram 1077 * port with no nameserver will cause an 1078 * ICMP port unreachable message to be returned. 1079 * If our datagram socket is "connected" to the 1080 * server, we get an ECONNREFUSED error on the next 1081 * socket operation, and select returns if the 1082 * error message is received. We can thus detect 1083 * the absence of a nameserver without timing out. 1084 */ 1085 if (random_bind(EXT(statp).nssocks[ns], nsap->sa_family) < 0) { 1086 Aerror(statp, stderr, "bind(dg)", errno, nsap, 1087 nsaplen); 1088 res_nclose(statp); 1089 return (0); 1090 } 1091 if (connect(EXT(statp).nssocks[ns], nsap, (socklen_t)nsaplen) < 0) { 1092 Aerror(statp, stderr, "connect(dg)", errno, nsap, 1093 nsaplen); 1094 res_nclose(statp); 1095 return (0); 1096 } 1097 #endif /* !CANNOT_CONNECT_DGRAM */ 1098 Dprint(statp->options & RES_DEBUG, 1099 (stdout, ";; new DG socket\n")) 1100 } 1101 s = EXT(statp).nssocks[ns]; 1102 #ifndef CANNOT_CONNECT_DGRAM 1103 if (send(s, (const char*)buf, (size_t)buflen, 0) != buflen) { 1104 Perror(statp, stderr, "send", errno); 1105 res_nclose(statp); 1106 return (0); 1107 } 1108 #else /* !CANNOT_CONNECT_DGRAM */ 1109 if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) 1110 { 1111 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 1112 res_nclose(statp); 1113 return (0); 1114 } 1115 #endif /* !CANNOT_CONNECT_DGRAM */ 1116 1117 /* 1118 * Wait for reply. 1119 */ 1120 seconds = get_timeout(statp, ns); 1121 now = evNowTime(); 1122 timeout = evConsTime((long)seconds, 0L); 1123 finish = evAddTime(now, timeout); 1124 retry: 1125 n = retrying_select(s, &dsmask, NULL, &finish); 1126 1127 if (n == 0) { 1128 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); 1129 *gotsomewhere = 1; 1130 return (0); 1131 } 1132 if (n < 0) { 1133 Perror(statp, stderr, "select", errno); 1134 res_nclose(statp); 1135 return (0); 1136 } 1137 errno = 0; 1138 fromlen = sizeof(from); 1139 resplen = recvfrom(s, (char*)ans, (size_t)anssiz,0, 1140 (struct sockaddr *)(void *)&from, &fromlen); 1141 if (resplen <= 0) { 1142 Perror(statp, stderr, "recvfrom", errno); 1143 res_nclose(statp); 1144 return (0); 1145 } 1146 *gotsomewhere = 1; 1147 if (resplen < HFIXEDSZ) { 1148 /* 1149 * Undersized message. 1150 */ 1151 Dprint(statp->options & RES_DEBUG, 1152 (stdout, ";; undersized: %d\n", 1153 resplen)); 1154 *terrno = EMSGSIZE; 1155 res_nclose(statp); 1156 return (0); 1157 } 1158 if (hp->id != anhp->id) { 1159 /* 1160 * response from old query, ignore it. 1161 * XXX - potential security hazard could 1162 * be detected here. 1163 */ 1164 #ifdef ANDROID_CHANGES 1165 __libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_OLD_RESPONSE); 1166 #endif 1167 DprintQ((statp->options & RES_DEBUG) || 1168 (statp->pfcode & RES_PRF_REPLY), 1169 (stdout, ";; old answer:\n"), 1170 ans, (resplen > anssiz) ? anssiz : resplen); 1171 goto retry; 1172 } 1173 if (!(statp->options & RES_INSECURE1) && 1174 !res_ourserver_p(statp, (struct sockaddr *)(void *)&from)) { 1175 /* 1176 * response from wrong server? ignore it. 1177 * XXX - potential security hazard could 1178 * be detected here. 1179 */ 1180 #ifdef ANDROID_CHANGES 1181 __libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_WRONG_SERVER); 1182 #endif 1183 DprintQ((statp->options & RES_DEBUG) || 1184 (statp->pfcode & RES_PRF_REPLY), 1185 (stdout, ";; not our server:\n"), 1186 ans, (resplen > anssiz) ? anssiz : resplen); 1187 goto retry; 1188 } 1189 #ifdef RES_USE_EDNS0 1190 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { 1191 /* 1192 * Do not retry if the server do not understand EDNS0. 1193 * The case has to be captured here, as FORMERR packet do not 1194 * carry query section, hence res_queriesmatch() returns 0. 1195 */ 1196 DprintQ(statp->options & RES_DEBUG, 1197 (stdout, "server rejected query with EDNS0:\n"), 1198 ans, (resplen > anssiz) ? anssiz : resplen); 1199 /* record the error */ 1200 statp->_flags |= RES_F_EDNS0ERR; 1201 res_nclose(statp); 1202 return (0); 1203 } 1204 #endif 1205 if (!(statp->options & RES_INSECURE2) && 1206 !res_queriesmatch(buf, buf + buflen, 1207 ans, ans + anssiz)) { 1208 /* 1209 * response contains wrong query? ignore it. 1210 * XXX - potential security hazard could 1211 * be detected here. 1212 */ 1213 #ifdef ANDROID_CHANGES 1214 __libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_WRONG_QUERY); 1215 #endif 1216 DprintQ((statp->options & RES_DEBUG) || 1217 (statp->pfcode & RES_PRF_REPLY), 1218 (stdout, ";; wrong query name:\n"), 1219 ans, (resplen > anssiz) ? anssiz : resplen); 1220 goto retry;; 1221 } 1222 if (anhp->rcode == SERVFAIL || 1223 anhp->rcode == NOTIMP || 1224 anhp->rcode == REFUSED) { 1225 DprintQ(statp->options & RES_DEBUG, 1226 (stdout, "server rejected query:\n"), 1227 ans, (resplen > anssiz) ? anssiz : resplen); 1228 res_nclose(statp); 1229 /* don't retry if called from dig */ 1230 if (!statp->pfcode) 1231 return (0); 1232 } 1233 if (!(statp->options & RES_IGNTC) && anhp->tc) { 1234 /* 1235 * To get the rest of answer, 1236 * use TCP with same server. 1237 */ 1238 Dprint(statp->options & RES_DEBUG, 1239 (stdout, ";; truncated answer\n")); 1240 *v_circuit = 1; 1241 res_nclose(statp); 1242 return (1); 1243 } 1244 /* 1245 * All is well, or the error is fatal. Signal that the 1246 * next nameserver ought not be tried. 1247 */ 1248 return (resplen); 1249 } 1250 1251 static void 1252 Aerror(const res_state statp, FILE *file, const char *string, int error, 1253 const struct sockaddr *address, int alen) 1254 { 1255 int save = errno; 1256 char hbuf[NI_MAXHOST]; 1257 char sbuf[NI_MAXSERV]; 1258 1259 alen = alen; 1260 1261 if ((statp->options & RES_DEBUG) != 0U) { 1262 if (getnameinfo(address, (socklen_t)alen, hbuf, sizeof(hbuf), 1263 sbuf, sizeof(sbuf), niflags)) { 1264 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1265 hbuf[sizeof(hbuf) - 1] = '\0'; 1266 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1267 sbuf[sizeof(sbuf) - 1] = '\0'; 1268 } 1269 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1270 string, hbuf, sbuf, strerror(error)); 1271 } 1272 errno = save; 1273 } 1274 1275 static void 1276 Perror(const res_state statp, FILE *file, const char *string, int error) { 1277 int save = errno; 1278 1279 if ((statp->options & RES_DEBUG) != 0U) 1280 fprintf(file, "res_send: %s: %s\n", 1281 string, strerror(error)); 1282 errno = save; 1283 } 1284 1285 static int 1286 sock_eq(struct sockaddr *a, struct sockaddr *b) { 1287 struct sockaddr_in *a4, *b4; 1288 struct sockaddr_in6 *a6, *b6; 1289 1290 if (a->sa_family != b->sa_family) 1291 return 0; 1292 switch (a->sa_family) { 1293 case AF_INET: 1294 a4 = (struct sockaddr_in *)(void *)a; 1295 b4 = (struct sockaddr_in *)(void *)b; 1296 return a4->sin_port == b4->sin_port && 1297 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1298 case AF_INET6: 1299 a6 = (struct sockaddr_in6 *)(void *)a; 1300 b6 = (struct sockaddr_in6 *)(void *)b; 1301 return a6->sin6_port == b6->sin6_port && 1302 #ifdef HAVE_SIN6_SCOPE_ID 1303 a6->sin6_scope_id == b6->sin6_scope_id && 1304 #endif 1305 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1306 default: 1307 return 0; 1308 } 1309 } 1310 1311 #ifdef NEED_PSELECT 1312 /* XXX needs to move to the porting library. */ 1313 static int 1314 pselect(int nfds, void *rfds, void *wfds, void *efds, 1315 struct timespec *tsp, const sigset_t *sigmask) 1316 { 1317 struct timeval tv, *tvp; 1318 sigset_t sigs; 1319 int n; 1320 1321 if (tsp) { 1322 tvp = &tv; 1323 tv = evTimeVal(*tsp); 1324 } else 1325 tvp = NULL; 1326 if (sigmask) 1327 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1328 n = select(nfds, rfds, wfds, efds, tvp); 1329 if (sigmask) 1330 sigprocmask(SIG_SETMASK, &sigs, NULL); 1331 if (tsp) 1332 *tsp = evTimeSpec(tv); 1333 return (n); 1334 } 1335 #endif 1336
