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 "logd.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 (statp->nscount == 0) { 374 errno = ESRCH; 375 return (-1); 376 } 377 if (anssiz < HFIXEDSZ) { 378 errno = EINVAL; 379 return (-1); 380 } 381 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY), 382 (stdout, ";; res_send()\n"), buf, buflen); 383 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ; 384 gotsomewhere = 0; 385 terrno = ETIMEDOUT; 386 387 #if USE_RESOLV_CACHE 388 cache = __get_res_cache(); 389 if (cache != NULL) { 390 int anslen = 0; 391 cache_status = _resolv_cache_lookup( 392 cache, buf, buflen, 393 ans, anssiz, &anslen); 394 395 if (cache_status == RESOLV_CACHE_FOUND) { 396 return anslen; 397 } 398 } 399 #endif 400 401 /* 402 * If the ns_addr_list in the resolver context has changed, then 403 * invalidate our cached copy and the associated timing data. 404 */ 405 if (EXT(statp).nscount != 0) { 406 int needclose = 0; 407 struct sockaddr_storage peer; 408 socklen_t peerlen; 409 410 if (EXT(statp).nscount != statp->nscount) 411 needclose++; 412 else 413 for (ns = 0; ns < statp->nscount; ns++) { 414 if (statp->nsaddr_list[ns].sin_family && 415 !sock_eq((struct sockaddr *)(void *)&statp->nsaddr_list[ns], 416 (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[ns])) { 417 needclose++; 418 break; 419 } 420 421 if (EXT(statp).nssocks[ns] == -1) 422 continue; 423 peerlen = sizeof(peer); 424 if (getpeername(EXT(statp).nssocks[ns], 425 (struct sockaddr *)(void *)&peer, &peerlen) < 0) { 426 needclose++; 427 break; 428 } 429 if (!sock_eq((struct sockaddr *)(void *)&peer, 430 get_nsaddr(statp, (size_t)ns))) { 431 needclose++; 432 break; 433 } 434 } 435 if (needclose) { 436 res_nclose(statp); 437 EXT(statp).nscount = 0; 438 } 439 } 440 441 /* 442 * Maybe initialize our private copy of the ns_addr_list. 443 */ 444 if (EXT(statp).nscount == 0) { 445 for (ns = 0; ns < statp->nscount; ns++) { 446 EXT(statp).nstimes[ns] = RES_MAXTIME; 447 EXT(statp).nssocks[ns] = -1; 448 if (!statp->nsaddr_list[ns].sin_family) 449 continue; 450 EXT(statp).ext->nsaddrs[ns].sin = 451 statp->nsaddr_list[ns]; 452 } 453 EXT(statp).nscount = statp->nscount; 454 } 455 456 /* 457 * Some resolvers want to even out the load on their nameservers. 458 * Note that RES_BLAST overrides RES_ROTATE. 459 */ 460 if ((statp->options & RES_ROTATE) != 0U && 461 (statp->options & RES_BLAST) == 0U) { 462 union res_sockaddr_union inu; 463 struct sockaddr_in ina; 464 int lastns = statp->nscount - 1; 465 int fd; 466 u_int16_t nstime; 467 468 if (EXT(statp).ext != NULL) 469 inu = EXT(statp).ext->nsaddrs[0]; 470 ina = statp->nsaddr_list[0]; 471 fd = EXT(statp).nssocks[0]; 472 nstime = EXT(statp).nstimes[0]; 473 for (ns = 0; ns < lastns; ns++) { 474 if (EXT(statp).ext != NULL) 475 EXT(statp).ext->nsaddrs[ns] = 476 EXT(statp).ext->nsaddrs[ns + 1]; 477 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1]; 478 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1]; 479 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1]; 480 } 481 if (EXT(statp).ext != NULL) 482 EXT(statp).ext->nsaddrs[lastns] = inu; 483 statp->nsaddr_list[lastns] = ina; 484 EXT(statp).nssocks[lastns] = fd; 485 EXT(statp).nstimes[lastns] = nstime; 486 } 487 488 /* 489 * Send request, RETRY times, or until successful. 490 */ 491 for (try = 0; try < statp->retry; try++) { 492 for (ns = 0; ns < statp->nscount; ns++) { 493 struct sockaddr *nsap; 494 int nsaplen; 495 nsap = get_nsaddr(statp, (size_t)ns); 496 nsaplen = get_salen(nsap); 497 statp->_flags &= ~RES_F_LASTMASK; 498 statp->_flags |= (ns << RES_F_LASTSHIFT); 499 same_ns: 500 if (statp->qhook) { 501 int done = 0, loops = 0; 502 503 do { 504 res_sendhookact act; 505 506 act = (*statp->qhook)(&nsap, &buf, &buflen, 507 ans, anssiz, &resplen); 508 switch (act) { 509 case res_goahead: 510 done = 1; 511 break; 512 case res_nextns: 513 res_nclose(statp); 514 goto next_ns; 515 case res_done: 516 return (resplen); 517 case res_modified: 518 /* give the hook another try */ 519 if (++loops < 42) /*doug adams*/ 520 break; 521 /*FALLTHROUGH*/ 522 case res_error: 523 /*FALLTHROUGH*/ 524 default: 525 goto fail; 526 } 527 } while (!done); 528 } 529 530 Dprint(((statp->options & RES_DEBUG) && 531 getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf), 532 NULL, 0, niflags) == 0), 533 (stdout, ";; Querying server (# %d) address = %s\n", 534 ns + 1, abuf)); 535 536 537 if (v_circuit) { 538 /* Use VC; at most one attempt per server. */ 539 try = statp->retry; 540 541 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, 542 ns); 543 544 if (DBG) { 545 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 546 "used send_vc %d\n", n); 547 } 548 549 if (n < 0) 550 goto fail; 551 if (n == 0) 552 goto next_ns; 553 resplen = n; 554 } else { 555 /* Use datagrams. */ 556 if (DBG) { 557 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 558 "using send_dg\n"); 559 } 560 561 n = send_dg(statp, buf, buflen, ans, anssiz, &terrno, 562 ns, &v_circuit, &gotsomewhere); 563 if (DBG) { 564 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 565 "used send_dg %d\n",n); 566 } 567 568 if (n < 0) 569 goto fail; 570 if (n == 0) 571 goto next_ns; 572 if (DBG) { 573 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 574 "time=%d, %d\n",time(NULL), time(NULL)%2); 575 } 576 if (v_circuit) 577 goto same_ns; 578 resplen = n; 579 } 580 581 Dprint((statp->options & RES_DEBUG) || 582 ((statp->pfcode & RES_PRF_REPLY) && 583 (statp->pfcode & RES_PRF_HEAD1)), 584 (stdout, ";; got answer:\n")); 585 586 DprintQ((statp->options & RES_DEBUG) || 587 (statp->pfcode & RES_PRF_REPLY), 588 (stdout, "%s", ""), 589 ans, (resplen > anssiz) ? anssiz : resplen); 590 591 #if USE_RESOLV_CACHE 592 if (cache_status == RESOLV_CACHE_NOTFOUND) { 593 _resolv_cache_add(cache, buf, buflen, 594 ans, resplen); 595 } 596 #endif 597 /* 598 * If we have temporarily opened a virtual circuit, 599 * or if we haven't been asked to keep a socket open, 600 * close the socket. 601 */ 602 if ((v_circuit && (statp->options & RES_USEVC) == 0U) || 603 (statp->options & RES_STAYOPEN) == 0U) { 604 res_nclose(statp); 605 } 606 if (statp->rhook) { 607 int done = 0, loops = 0; 608 609 do { 610 res_sendhookact act; 611 612 act = (*statp->rhook)(nsap, buf, buflen, 613 ans, anssiz, &resplen); 614 switch (act) { 615 case res_goahead: 616 case res_done: 617 done = 1; 618 break; 619 case res_nextns: 620 res_nclose(statp); 621 goto next_ns; 622 case res_modified: 623 /* give the hook another try */ 624 if (++loops < 42) /*doug adams*/ 625 break; 626 /*FALLTHROUGH*/ 627 case res_error: 628 /*FALLTHROUGH*/ 629 default: 630 goto fail; 631 } 632 } while (!done); 633 634 } 635 return (resplen); 636 next_ns: ; 637 } /*foreach ns*/ 638 } /*foreach retry*/ 639 res_nclose(statp); 640 if (!v_circuit) { 641 if (!gotsomewhere) 642 errno = ECONNREFUSED; /* no nameservers found */ 643 else 644 errno = ETIMEDOUT; /* no answer obtained */ 645 } else 646 errno = terrno; 647 return (-1); 648 fail: 649 res_nclose(statp); 650 return (-1); 651 } 652 653 /* Private */ 654 655 static int 656 get_salen(sa) 657 const struct sockaddr *sa; 658 { 659 660 #ifdef HAVE_SA_LEN 661 /* There are people do not set sa_len. Be forgiving to them. */ 662 if (sa->sa_len) 663 return (sa->sa_len); 664 #endif 665 666 if (sa->sa_family == AF_INET) 667 return (sizeof(struct sockaddr_in)); 668 else if (sa->sa_family == AF_INET6) 669 return (sizeof(struct sockaddr_in6)); 670 else 671 return (0); /* unknown, die on connect */ 672 } 673 674 /* 675 * pick appropriate nsaddr_list for use. see res_init() for initialization. 676 */ 677 static struct sockaddr * 678 get_nsaddr(statp, n) 679 res_state statp; 680 size_t n; 681 { 682 683 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) { 684 /* 685 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger 686 * than struct sockaddr, and 687 * - user code did not update statp->nsaddr_list[n]. 688 */ 689 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n]; 690 } else { 691 /* 692 * - user code updated statp->nsaddr_list[n], or 693 * - statp->nsaddr_list[n] has the same content as 694 * EXT(statp).ext->nsaddrs[n]. 695 */ 696 return (struct sockaddr *)(void *)&statp->nsaddr_list[n]; 697 } 698 } 699 700 static int get_timeout(const res_state statp, const int ns) 701 { 702 int timeout = (statp->retrans << ns); 703 if (ns > 0) { 704 timeout /= statp->nscount; 705 } 706 if (timeout <= 0) { 707 timeout = 1; 708 } 709 if (DBG) { 710 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 711 "using timeout of %d sec\n", timeout); 712 } 713 714 return timeout; 715 } 716 717 static int 718 send_vc(res_state statp, 719 const u_char *buf, int buflen, u_char *ans, int anssiz, 720 int *terrno, int ns) 721 { 722 const HEADER *hp = (const HEADER *)(const void *)buf; 723 HEADER *anhp = (HEADER *)(void *)ans; 724 struct sockaddr *nsap; 725 int nsaplen; 726 int truncating, connreset, resplen, n; 727 struct iovec iov[2]; 728 u_short len; 729 u_char *cp; 730 void *tmp; 731 732 if (DBG) { 733 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", "using send_vc\n"); 734 } 735 736 nsap = get_nsaddr(statp, (size_t)ns); 737 nsaplen = get_salen(nsap); 738 739 connreset = 0; 740 same_ns: 741 truncating = 0; 742 743 /* Are we still talking to whom we want to talk to? */ 744 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { 745 struct sockaddr_storage peer; 746 socklen_t size = sizeof peer; 747 748 if (getpeername(statp->_vcsock, 749 (struct sockaddr *)(void *)&peer, &size) < 0 || 750 !sock_eq((struct sockaddr *)(void *)&peer, nsap)) { 751 res_nclose(statp); 752 statp->_flags &= ~RES_F_VC; 753 } 754 } 755 756 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) { 757 if (statp->_vcsock >= 0) 758 res_nclose(statp); 759 760 statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0); 761 if (statp->_vcsock > highestFD) { 762 res_nclose(statp); 763 errno = ENOTSOCK; 764 } 765 if (statp->_vcsock < 0) { 766 switch (errno) { 767 case EPROTONOSUPPORT: 768 #ifdef EPFNOSUPPORT 769 case EPFNOSUPPORT: 770 #endif 771 case EAFNOSUPPORT: 772 Perror(statp, stderr, "socket(vc)", errno); 773 return (0); 774 default: 775 *terrno = errno; 776 Perror(statp, stderr, "socket(vc)", errno); 777 return (-1); 778 } 779 } 780 errno = 0; 781 if (random_bind(statp->_vcsock,nsap->sa_family) < 0) { 782 *terrno = errno; 783 Aerror(statp, stderr, "bind/vc", errno, nsap, 784 nsaplen); 785 res_nclose(statp); 786 return (0); 787 } 788 if (connect_with_timeout(statp->_vcsock, nsap, (socklen_t)nsaplen, 789 get_timeout(statp, ns)) < 0) { 790 *terrno = errno; 791 Aerror(statp, stderr, "connect/vc", errno, nsap, 792 nsaplen); 793 res_nclose(statp); 794 return (0); 795 } 796 statp->_flags |= RES_F_VC; 797 } 798 799 /* 800 * Send length & message 801 */ 802 ns_put16((u_short)buflen, (u_char*)(void *)&len); 803 iov[0] = evConsIovec(&len, INT16SZ); 804 DE_CONST(buf, tmp); 805 iov[1] = evConsIovec(tmp, (size_t)buflen); 806 if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { 807 *terrno = errno; 808 Perror(statp, stderr, "write failed", errno); 809 res_nclose(statp); 810 return (0); 811 } 812 /* 813 * Receive length & response 814 */ 815 read_len: 816 cp = ans; 817 len = INT16SZ; 818 while ((n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0) { 819 cp += n; 820 if ((len -= n) == 0) 821 break; 822 } 823 if (n <= 0) { 824 *terrno = errno; 825 Perror(statp, stderr, "read failed", errno); 826 res_nclose(statp); 827 /* 828 * A long running process might get its TCP 829 * connection reset if the remote server was 830 * restarted. Requery the server instead of 831 * trying a new one. When there is only one 832 * server, this means that a query might work 833 * instead of failing. We only allow one reset 834 * per query to prevent looping. 835 */ 836 if (*terrno == ECONNRESET && !connreset) { 837 connreset = 1; 838 res_nclose(statp); 839 goto same_ns; 840 } 841 res_nclose(statp); 842 return (0); 843 } 844 resplen = ns_get16(ans); 845 if (resplen > anssiz) { 846 Dprint(statp->options & RES_DEBUG, 847 (stdout, ";; response truncated\n") 848 ); 849 truncating = 1; 850 len = anssiz; 851 } else 852 len = resplen; 853 if (len < HFIXEDSZ) { 854 /* 855 * Undersized message. 856 */ 857 Dprint(statp->options & RES_DEBUG, 858 (stdout, ";; undersized: %d\n", len)); 859 *terrno = EMSGSIZE; 860 res_nclose(statp); 861 return (0); 862 } 863 cp = ans; 864 while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0){ 865 cp += n; 866 len -= n; 867 } 868 if (n <= 0) { 869 *terrno = errno; 870 Perror(statp, stderr, "read(vc)", errno); 871 res_nclose(statp); 872 return (0); 873 } 874 if (truncating) { 875 /* 876 * Flush rest of answer so connection stays in synch. 877 */ 878 anhp->tc = 1; 879 len = resplen - anssiz; 880 while (len != 0) { 881 char junk[PACKETSZ]; 882 883 n = read(statp->_vcsock, junk, 884 (len > sizeof junk) ? sizeof junk : len); 885 if (n > 0) 886 len -= n; 887 else 888 break; 889 } 890 } 891 /* 892 * If the calling applicating has bailed out of 893 * a previous call and failed to arrange to have 894 * the circuit closed or the server has got 895 * itself confused, then drop the packet and 896 * wait for the correct one. 897 */ 898 if (hp->id != anhp->id) { 899 DprintQ((statp->options & RES_DEBUG) || 900 (statp->pfcode & RES_PRF_REPLY), 901 (stdout, ";; old answer (unexpected):\n"), 902 ans, (resplen > anssiz) ? anssiz: resplen); 903 goto read_len; 904 } 905 906 /* 907 * All is well, or the error is fatal. Signal that the 908 * next nameserver ought not be tried. 909 */ 910 return (resplen); 911 } 912 913 /* return -1 on error (errno set), 0 on success */ 914 static int 915 connect_with_timeout(int sock, const struct sockaddr *nsap, socklen_t salen, int sec) 916 { 917 int res, origflags; 918 fd_set rset, wset; 919 struct timespec now, timeout, finish; 920 921 origflags = fcntl(sock, F_GETFL, 0); 922 fcntl(sock, F_SETFL, origflags | O_NONBLOCK); 923 924 res = connect(sock, nsap, salen); 925 if (res < 0 && errno != EINPROGRESS) { 926 res = -1; 927 goto done; 928 } 929 if (res != 0) { 930 now = evNowTime(); 931 timeout = evConsTime((long)sec, 0L); 932 finish = evAddTime(now, timeout); 933 if (DBG) { 934 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 935 " %d send_vc\n", sock); 936 } 937 938 res = retrying_select(sock, &rset, &wset, &finish); 939 if (res <= 0) { 940 res = -1; 941 } 942 } 943 done: 944 fcntl(sock, F_SETFL, origflags); 945 if (DBG) { 946 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 947 " %d connect_with_timeout returning %s\n", sock, res); 948 } 949 return res; 950 } 951 952 static int 953 retrying_select(const int sock, fd_set *readset, fd_set *writeset, const struct timespec *finish) 954 { 955 struct timespec now, timeout; 956 int n, error; 957 socklen_t len; 958 959 960 retry: 961 if (DBG) { 962 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", " %d retying_select\n", sock); 963 } 964 965 now = evNowTime(); 966 if (readset) { 967 FD_ZERO(readset); 968 FD_SET(sock, readset); 969 } 970 if (writeset) { 971 FD_ZERO(writeset); 972 FD_SET(sock, writeset); 973 } 974 if (evCmpTime(*finish, now) > 0) 975 timeout = evSubTime(*finish, now); 976 else 977 timeout = evConsTime(0L, 0L); 978 979 n = pselect(sock + 1, readset, writeset, NULL, &timeout, NULL); 980 if (n == 0) { 981 if (DBG) { 982 __libc_android_log_print(ANDROID_LOG_DEBUG, " libc", 983 " %d retrying_select timeout\n", sock); 984 } 985 errno = ETIMEDOUT; 986 return 0; 987 } 988 if (n < 0) { 989 if (errno == EINTR) 990 goto retry; 991 if (DBG) { 992 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 993 " %d retrying_select got error %d\n",sock, n); 994 } 995 return n; 996 } 997 if ((readset && FD_ISSET(sock, readset)) || (writeset && FD_ISSET(sock, writeset))) { 998 len = sizeof(error); 999 if (getsockopt(sock, SOL_SOCKET, SO_ERROR, &error, &len) < 0 || error) { 1000 errno = error; 1001 if (DBG) { 1002 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 1003 " %d retrying_select dot error2 %d\n", sock, errno); 1004 } 1005 1006 return -1; 1007 } 1008 } 1009 if (DBG) { 1010 __libc_android_log_print(ANDROID_LOG_DEBUG, "libc", 1011 " %d retrying_select returning %d for %d\n",sock, n); 1012 } 1013 1014 return n; 1015 } 1016 1017 1018 static int 1019 send_dg(res_state statp, 1020 const u_char *buf, int buflen, u_char *ans, int anssiz, 1021 int *terrno, int ns, int *v_circuit, int *gotsomewhere) 1022 { 1023 const HEADER *hp = (const HEADER *)(const void *)buf; 1024 HEADER *anhp = (HEADER *)(void *)ans; 1025 const struct sockaddr *nsap; 1026 int nsaplen; 1027 struct timespec now, timeout, finish; 1028 fd_set dsmask; 1029 struct sockaddr_storage from; 1030 socklen_t fromlen; 1031 int resplen, seconds, n, s; 1032 1033 nsap = get_nsaddr(statp, (size_t)ns); 1034 nsaplen = get_salen(nsap); 1035 if (EXT(statp).nssocks[ns] == -1) { 1036 EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0); 1037 if (EXT(statp).nssocks[ns] > highestFD) { 1038 res_nclose(statp); 1039 errno = ENOTSOCK; 1040 } 1041 if (EXT(statp).nssocks[ns] < 0) { 1042 switch (errno) { 1043 case EPROTONOSUPPORT: 1044 #ifdef EPFNOSUPPORT 1045 case EPFNOSUPPORT: 1046 #endif 1047 case EAFNOSUPPORT: 1048 Perror(statp, stderr, "socket(dg)", errno); 1049 return (0); 1050 default: 1051 *terrno = errno; 1052 Perror(statp, stderr, "socket(dg)", errno); 1053 return (-1); 1054 } 1055 } 1056 #ifndef CANNOT_CONNECT_DGRAM 1057 /* 1058 * On a 4.3BSD+ machine (client and server, 1059 * actually), sending to a nameserver datagram 1060 * port with no nameserver will cause an 1061 * ICMP port unreachable message to be returned. 1062 * If our datagram socket is "connected" to the 1063 * server, we get an ECONNREFUSED error on the next 1064 * socket operation, and select returns if the 1065 * error message is received. We can thus detect 1066 * the absence of a nameserver without timing out. 1067 */ 1068 if (random_bind(EXT(statp).nssocks[ns], nsap->sa_family) < 0) { 1069 Aerror(statp, stderr, "bind(dg)", errno, nsap, 1070 nsaplen); 1071 res_nclose(statp); 1072 return (0); 1073 } 1074 if (connect(EXT(statp).nssocks[ns], nsap, (socklen_t)nsaplen) < 0) { 1075 Aerror(statp, stderr, "connect(dg)", errno, nsap, 1076 nsaplen); 1077 res_nclose(statp); 1078 return (0); 1079 } 1080 #endif /* !CANNOT_CONNECT_DGRAM */ 1081 Dprint(statp->options & RES_DEBUG, 1082 (stdout, ";; new DG socket\n")) 1083 } 1084 s = EXT(statp).nssocks[ns]; 1085 #ifndef CANNOT_CONNECT_DGRAM 1086 if (send(s, (const char*)buf, (size_t)buflen, 0) != buflen) { 1087 Perror(statp, stderr, "send", errno); 1088 res_nclose(statp); 1089 return (0); 1090 } 1091 #else /* !CANNOT_CONNECT_DGRAM */ 1092 if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) 1093 { 1094 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 1095 res_nclose(statp); 1096 return (0); 1097 } 1098 #endif /* !CANNOT_CONNECT_DGRAM */ 1099 1100 /* 1101 * Wait for reply. 1102 */ 1103 seconds = get_timeout(statp, ns); 1104 now = evNowTime(); 1105 timeout = evConsTime((long)seconds, 0L); 1106 finish = evAddTime(now, timeout); 1107 retry: 1108 n = retrying_select(s, &dsmask, NULL, &finish); 1109 1110 if (n == 0) { 1111 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); 1112 *gotsomewhere = 1; 1113 return (0); 1114 } 1115 if (n < 0) { 1116 Perror(statp, stderr, "select", errno); 1117 res_nclose(statp); 1118 return (0); 1119 } 1120 errno = 0; 1121 fromlen = sizeof(from); 1122 resplen = recvfrom(s, (char*)ans, (size_t)anssiz,0, 1123 (struct sockaddr *)(void *)&from, &fromlen); 1124 if (resplen <= 0) { 1125 Perror(statp, stderr, "recvfrom", errno); 1126 res_nclose(statp); 1127 return (0); 1128 } 1129 *gotsomewhere = 1; 1130 if (resplen < HFIXEDSZ) { 1131 /* 1132 * Undersized message. 1133 */ 1134 Dprint(statp->options & RES_DEBUG, 1135 (stdout, ";; undersized: %d\n", 1136 resplen)); 1137 *terrno = EMSGSIZE; 1138 res_nclose(statp); 1139 return (0); 1140 } 1141 if (hp->id != anhp->id) { 1142 /* 1143 * response from old query, ignore it. 1144 * XXX - potential security hazard could 1145 * be detected here. 1146 */ 1147 DprintQ((statp->options & RES_DEBUG) || 1148 (statp->pfcode & RES_PRF_REPLY), 1149 (stdout, ";; old answer:\n"), 1150 ans, (resplen > anssiz) ? anssiz : resplen); 1151 goto retry; 1152 } 1153 if (!(statp->options & RES_INSECURE1) && 1154 !res_ourserver_p(statp, (struct sockaddr *)(void *)&from)) { 1155 /* 1156 * response from wrong server? ignore it. 1157 * XXX - potential security hazard could 1158 * be detected here. 1159 */ 1160 DprintQ((statp->options & RES_DEBUG) || 1161 (statp->pfcode & RES_PRF_REPLY), 1162 (stdout, ";; not our server:\n"), 1163 ans, (resplen > anssiz) ? anssiz : resplen); 1164 goto retry; 1165 } 1166 #ifdef RES_USE_EDNS0 1167 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { 1168 /* 1169 * Do not retry if the server do not understand EDNS0. 1170 * The case has to be captured here, as FORMERR packet do not 1171 * carry query section, hence res_queriesmatch() returns 0. 1172 */ 1173 DprintQ(statp->options & RES_DEBUG, 1174 (stdout, "server rejected query with EDNS0:\n"), 1175 ans, (resplen > anssiz) ? anssiz : resplen); 1176 /* record the error */ 1177 statp->_flags |= RES_F_EDNS0ERR; 1178 res_nclose(statp); 1179 return (0); 1180 } 1181 #endif 1182 if (!(statp->options & RES_INSECURE2) && 1183 !res_queriesmatch(buf, buf + buflen, 1184 ans, ans + anssiz)) { 1185 /* 1186 * response contains wrong query? ignore it. 1187 * XXX - potential security hazard could 1188 * be detected here. 1189 */ 1190 DprintQ((statp->options & RES_DEBUG) || 1191 (statp->pfcode & RES_PRF_REPLY), 1192 (stdout, ";; wrong query name:\n"), 1193 ans, (resplen > anssiz) ? anssiz : resplen); 1194 goto retry;; 1195 } 1196 if (anhp->rcode == SERVFAIL || 1197 anhp->rcode == NOTIMP || 1198 anhp->rcode == REFUSED) { 1199 DprintQ(statp->options & RES_DEBUG, 1200 (stdout, "server rejected query:\n"), 1201 ans, (resplen > anssiz) ? anssiz : resplen); 1202 res_nclose(statp); 1203 /* don't retry if called from dig */ 1204 if (!statp->pfcode) 1205 return (0); 1206 } 1207 if (!(statp->options & RES_IGNTC) && anhp->tc) { 1208 /* 1209 * To get the rest of answer, 1210 * use TCP with same server. 1211 */ 1212 Dprint(statp->options & RES_DEBUG, 1213 (stdout, ";; truncated answer\n")); 1214 *v_circuit = 1; 1215 res_nclose(statp); 1216 return (1); 1217 } 1218 /* 1219 * All is well, or the error is fatal. Signal that the 1220 * next nameserver ought not be tried. 1221 */ 1222 return (resplen); 1223 } 1224 1225 static void 1226 Aerror(const res_state statp, FILE *file, const char *string, int error, 1227 const struct sockaddr *address, int alen) 1228 { 1229 int save = errno; 1230 char hbuf[NI_MAXHOST]; 1231 char sbuf[NI_MAXSERV]; 1232 1233 alen = alen; 1234 1235 if ((statp->options & RES_DEBUG) != 0U) { 1236 if (getnameinfo(address, (socklen_t)alen, hbuf, sizeof(hbuf), 1237 sbuf, sizeof(sbuf), niflags)) { 1238 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1239 hbuf[sizeof(hbuf) - 1] = '\0'; 1240 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1241 sbuf[sizeof(sbuf) - 1] = '\0'; 1242 } 1243 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1244 string, hbuf, sbuf, strerror(error)); 1245 } 1246 errno = save; 1247 } 1248 1249 static void 1250 Perror(const res_state statp, FILE *file, const char *string, int error) { 1251 int save = errno; 1252 1253 if ((statp->options & RES_DEBUG) != 0U) 1254 fprintf(file, "res_send: %s: %s\n", 1255 string, strerror(error)); 1256 errno = save; 1257 } 1258 1259 static int 1260 sock_eq(struct sockaddr *a, struct sockaddr *b) { 1261 struct sockaddr_in *a4, *b4; 1262 struct sockaddr_in6 *a6, *b6; 1263 1264 if (a->sa_family != b->sa_family) 1265 return 0; 1266 switch (a->sa_family) { 1267 case AF_INET: 1268 a4 = (struct sockaddr_in *)(void *)a; 1269 b4 = (struct sockaddr_in *)(void *)b; 1270 return a4->sin_port == b4->sin_port && 1271 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1272 case AF_INET6: 1273 a6 = (struct sockaddr_in6 *)(void *)a; 1274 b6 = (struct sockaddr_in6 *)(void *)b; 1275 return a6->sin6_port == b6->sin6_port && 1276 #ifdef HAVE_SIN6_SCOPE_ID 1277 a6->sin6_scope_id == b6->sin6_scope_id && 1278 #endif 1279 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1280 default: 1281 return 0; 1282 } 1283 } 1284 1285 #ifdef NEED_PSELECT 1286 /* XXX needs to move to the porting library. */ 1287 static int 1288 pselect(int nfds, void *rfds, void *wfds, void *efds, 1289 struct timespec *tsp, const sigset_t *sigmask) 1290 { 1291 struct timeval tv, *tvp; 1292 sigset_t sigs; 1293 int n; 1294 1295 if (tsp) { 1296 tvp = &tv; 1297 tv = evTimeVal(*tsp); 1298 } else 1299 tvp = NULL; 1300 if (sigmask) 1301 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1302 n = select(nfds, rfds, wfds, efds, tvp); 1303 if (sigmask) 1304 sigprocmask(SIG_SETMASK, &sigs, NULL); 1305 if (tsp) 1306 *tsp = evTimeSpec(tv); 1307 return (n); 1308 } 1309 #endif 1310
