gethostbydns.c revision 145512
1/* 2 * ++Copyright++ 1985, 1988, 1993 3 * - 4 * Copyright (c) 1985, 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * - 35 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 36 * 37 * Permission to use, copy, modify, and distribute this software for any 38 * purpose with or without fee is hereby granted, provided that the above 39 * copyright notice and this permission notice appear in all copies, and that 40 * the name of Digital Equipment Corporation not be used in advertising or 41 * publicity pertaining to distribution of the document or software without 42 * specific, written prior permission. 43 * 44 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 45 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 46 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 47 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 48 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 49 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 50 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 51 * SOFTWARE. 52 * - 53 * --Copyright-- 54 */ 55 56#if defined(LIBC_SCCS) && !defined(lint) 57static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93"; 58static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $"; 59#endif /* LIBC_SCCS and not lint */ 60#include <sys/cdefs.h> 61__FBSDID("$FreeBSD: head/lib/libc/net/gethostbydns.c 145512 2005-04-25 17:36:28Z ume $"); 62 63#include <sys/types.h> 64#include <sys/param.h> 65#include <sys/socket.h> 66#include <netinet/in.h> 67#include <arpa/inet.h> 68#include <arpa/nameser.h> 69 70#include <stdio.h> 71#include <stdlib.h> 72#include <unistd.h> 73#include <string.h> 74#include <netdb.h> 75#include <resolv.h> 76#include <ctype.h> 77#include <errno.h> 78#include <syslog.h> 79#include <stdarg.h> 80#include <nsswitch.h> 81 82#include "res_config.h" 83 84#define SPRINTF(x) ((size_t)sprintf x) 85 86#define MAXALIASES 35 87#define MAXADDRS 35 88 89static const char AskedForGot[] = 90 "gethostby*.gethostanswer: asked for \"%s\", got \"%s\""; 91 92static char *h_addr_ptrs[MAXADDRS + 1]; 93 94static struct hostent host; 95static char *host_aliases[MAXALIASES]; 96static char hostbuf[8*1024]; 97static u_char host_addr[16]; /* IPv4 or IPv6 */ 98 99#ifdef RESOLVSORT 100static void addrsort(char **, int); 101#endif 102 103#ifdef DEBUG 104static void dprintf(char *, int) __printflike(1, 0); 105#endif 106 107#define MAXPACKET (64*1024) 108 109typedef union { 110 HEADER hdr; 111 u_char buf[MAXPACKET]; 112} querybuf; 113 114typedef union { 115 int32_t al; 116 char ac; 117} align; 118 119int _dns_ttl_; 120 121#ifdef DEBUG 122static void 123dprintf(msg, num) 124 char *msg; 125 int num; 126{ 127 if (_res.options & RES_DEBUG) { 128 int save = errno; 129 130 printf(msg, num); 131 errno = save; 132 } 133} 134#else 135# define dprintf(msg, num) /*nada*/ 136#endif 137 138#define BOUNDED_INCR(x) \ 139 do { \ 140 cp += x; \ 141 if (cp > eom) { \ 142 h_errno = NO_RECOVERY; \ 143 return (NULL); \ 144 } \ 145 } while (0) 146 147#define BOUNDS_CHECK(ptr, count) \ 148 do { \ 149 if ((ptr) + (count) > eom) { \ 150 h_errno = NO_RECOVERY; \ 151 return (NULL); \ 152 } \ 153 } while (0) 154 155static struct hostent * 156gethostanswer(answer, anslen, qname, qtype) 157 const querybuf *answer; 158 int anslen; 159 const char *qname; 160 int qtype; 161{ 162 const HEADER *hp; 163 const u_char *cp; 164 int n; 165 const u_char *eom, *erdata; 166 char *bp, *ep, **ap, **hap; 167 int type, class, ancount, qdcount; 168 int haveanswer, had_error; 169 int toobig = 0; 170 char tbuf[MAXDNAME]; 171 const char *tname; 172 int (*name_ok)(const char *); 173 174 tname = qname; 175 host.h_name = NULL; 176 eom = answer->buf + anslen; 177 switch (qtype) { 178 case T_A: 179 case T_AAAA: 180 name_ok = res_hnok; 181 break; 182 case T_PTR: 183 name_ok = res_dnok; 184 break; 185 default: 186 h_errno = NO_RECOVERY; 187 return (NULL); /* XXX should be abort(); */ 188 } 189 /* 190 * find first satisfactory answer 191 */ 192 hp = &answer->hdr; 193 ancount = ntohs(hp->ancount); 194 qdcount = ntohs(hp->qdcount); 195 bp = hostbuf; 196 ep = hostbuf + sizeof hostbuf; 197 cp = answer->buf; 198 BOUNDED_INCR(HFIXEDSZ); 199 if (qdcount != 1) { 200 h_errno = NO_RECOVERY; 201 return (NULL); 202 } 203 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 204 if ((n < 0) || !(*name_ok)(bp)) { 205 h_errno = NO_RECOVERY; 206 return (NULL); 207 } 208 BOUNDED_INCR(n + QFIXEDSZ); 209 if (qtype == T_A || qtype == T_AAAA) { 210 /* res_send() has already verified that the query name is the 211 * same as the one we sent; this just gets the expanded name 212 * (i.e., with the succeeding search-domain tacked on). 213 */ 214 n = strlen(bp) + 1; /* for the \0 */ 215 if (n >= MAXHOSTNAMELEN) { 216 h_errno = NO_RECOVERY; 217 return (NULL); 218 } 219 host.h_name = bp; 220 bp += n; 221 /* The qname can be abbreviated, but h_name is now absolute. */ 222 qname = host.h_name; 223 } 224 ap = host_aliases; 225 *ap = NULL; 226 host.h_aliases = host_aliases; 227 hap = h_addr_ptrs; 228 *hap = NULL; 229 host.h_addr_list = h_addr_ptrs; 230 haveanswer = 0; 231 had_error = 0; 232 _dns_ttl_ = -1; 233 while (ancount-- > 0 && cp < eom && !had_error) { 234 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 235 if ((n < 0) || !(*name_ok)(bp)) { 236 had_error++; 237 continue; 238 } 239 cp += n; /* name */ 240 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ); 241 type = _getshort(cp); 242 cp += INT16SZ; /* type */ 243 class = _getshort(cp); 244 cp += INT16SZ; /* class */ 245 if (qtype == T_A && type == T_A) 246 _dns_ttl_ = _getlong(cp); 247 cp += INT32SZ; /* TTL */ 248 n = _getshort(cp); 249 cp += INT16SZ; /* len */ 250 BOUNDS_CHECK(cp, n); 251 erdata = cp + n; 252 if (class != C_IN) { 253 /* XXX - debug? syslog? */ 254 cp += n; 255 continue; /* XXX - had_error++ ? */ 256 } 257 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) { 258 if (ap >= &host_aliases[MAXALIASES-1]) 259 continue; 260 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); 261 if ((n < 0) || !(*name_ok)(tbuf)) { 262 had_error++; 263 continue; 264 } 265 cp += n; 266 if (cp != erdata) { 267 h_errno = NO_RECOVERY; 268 return (NULL); 269 } 270 /* Store alias. */ 271 *ap++ = bp; 272 n = strlen(bp) + 1; /* for the \0 */ 273 if (n >= MAXHOSTNAMELEN) { 274 had_error++; 275 continue; 276 } 277 bp += n; 278 /* Get canonical name. */ 279 n = strlen(tbuf) + 1; /* for the \0 */ 280 if (n > ep - bp || n >= MAXHOSTNAMELEN) { 281 had_error++; 282 continue; 283 } 284 strcpy(bp, tbuf); 285 host.h_name = bp; 286 bp += n; 287 continue; 288 } 289 if (qtype == T_PTR && type == T_CNAME) { 290 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); 291 if (n < 0 || !res_dnok(tbuf)) { 292 had_error++; 293 continue; 294 } 295 cp += n; 296 if (cp != erdata) { 297 h_errno = NO_RECOVERY; 298 return (NULL); 299 } 300 /* Get canonical name. */ 301 n = strlen(tbuf) + 1; /* for the \0 */ 302 if (n > ep - bp || n >= MAXHOSTNAMELEN) { 303 had_error++; 304 continue; 305 } 306 strcpy(bp, tbuf); 307 tname = bp; 308 bp += n; 309 continue; 310 } 311 if (type != qtype) { 312 if (type != T_SIG) 313 syslog(LOG_NOTICE|LOG_AUTH, 314 "gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"", 315 qname, p_class(C_IN), p_type(qtype), 316 p_type(type)); 317 cp += n; 318 continue; /* XXX - had_error++ ? */ 319 } 320 switch (type) { 321 case T_PTR: 322 if (strcasecmp(tname, bp) != 0) { 323 syslog(LOG_NOTICE|LOG_AUTH, 324 AskedForGot, qname, bp); 325 cp += n; 326 continue; /* XXX - had_error++ ? */ 327 } 328 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 329 if ((n < 0) || !res_hnok(bp)) { 330 had_error++; 331 break; 332 } 333#if MULTI_PTRS_ARE_ALIASES 334 cp += n; 335 if (cp != erdata) { 336 h_errno = NO_RECOVERY; 337 return (NULL); 338 } 339 if (!haveanswer) 340 host.h_name = bp; 341 else if (ap < &host_aliases[MAXALIASES-1]) 342 *ap++ = bp; 343 else 344 n = -1; 345 if (n != -1) { 346 n = strlen(bp) + 1; /* for the \0 */ 347 if (n >= MAXHOSTNAMELEN) { 348 had_error++; 349 break; 350 } 351 bp += n; 352 } 353 break; 354#else 355 host.h_name = bp; 356 if (_res.options & RES_USE_INET6) { 357 n = strlen(bp) + 1; /* for the \0 */ 358 if (n >= MAXHOSTNAMELEN) { 359 had_error++; 360 break; 361 } 362 bp += n; 363 _map_v4v6_hostent(&host, &bp, &ep); 364 } 365 h_errno = NETDB_SUCCESS; 366 return (&host); 367#endif 368 case T_A: 369 case T_AAAA: 370 if (strcasecmp(host.h_name, bp) != 0) { 371 syslog(LOG_NOTICE|LOG_AUTH, 372 AskedForGot, host.h_name, bp); 373 cp += n; 374 continue; /* XXX - had_error++ ? */ 375 } 376 if (n != host.h_length) { 377 cp += n; 378 continue; 379 } 380 if (!haveanswer) { 381 int nn; 382 383 host.h_name = bp; 384 nn = strlen(bp) + 1; /* for the \0 */ 385 bp += nn; 386 } 387 388 bp += sizeof(align) - ((u_long)bp % sizeof(align)); 389 390 if (bp + n >= ep) { 391 dprintf("size (%d) too big\n", n); 392 had_error++; 393 continue; 394 } 395 if (hap >= &h_addr_ptrs[MAXADDRS-1]) { 396 if (!toobig++) 397 dprintf("Too many addresses (%d)\n", 398 MAXADDRS); 399 cp += n; 400 continue; 401 } 402 bcopy(cp, *hap++ = bp, n); 403 bp += n; 404 cp += n; 405 if (cp != erdata) { 406 h_errno = NO_RECOVERY; 407 return (NULL); 408 } 409 break; 410 default: 411 dprintf("Impossible condition (type=%d)\n", type); 412 h_errno = NO_RECOVERY; 413 return (NULL); 414 /* BIND has abort() here, too risky on bad data */ 415 } 416 if (!had_error) 417 haveanswer++; 418 } 419 if (haveanswer) { 420 *ap = NULL; 421 *hap = NULL; 422# if defined(RESOLVSORT) 423 /* 424 * Note: we sort even if host can take only one address 425 * in its return structures - should give it the "best" 426 * address in that case, not some random one 427 */ 428 if (_res.nsort && haveanswer > 1 && qtype == T_A) 429 addrsort(h_addr_ptrs, haveanswer); 430# endif /*RESOLVSORT*/ 431 if (!host.h_name) { 432 n = strlen(qname) + 1; /* for the \0 */ 433 if (n > ep - bp || n >= MAXHOSTNAMELEN) 434 goto no_recovery; 435 strcpy(bp, qname); 436 host.h_name = bp; 437 bp += n; 438 } 439 if (_res.options & RES_USE_INET6) 440 _map_v4v6_hostent(&host, &bp, &ep); 441 h_errno = NETDB_SUCCESS; 442 return (&host); 443 } 444 no_recovery: 445 h_errno = NO_RECOVERY; 446 return (NULL); 447} 448 449struct hostent * 450__dns_getanswer(answer, anslen, qname, qtype) 451 const char *answer; 452 int anslen; 453 const char *qname; 454 int qtype; 455{ 456 switch(qtype) { 457 case T_AAAA: 458 host.h_addrtype = AF_INET6; 459 host.h_length = IN6ADDRSZ; 460 break; 461 case T_A: 462 default: 463 host.h_addrtype = AF_INET; 464 host.h_length = INADDRSZ; 465 break; 466 } 467 468 return(gethostanswer((const querybuf *)answer, anslen, qname, qtype)); 469} 470 471int 472_dns_gethostbyname(void *rval, void *cb_data, va_list ap) 473{ 474 const char *name; 475 int af; 476 querybuf *buf; 477 int n, size, type; 478 479 name = va_arg(ap, const char *); 480 af = va_arg(ap, int); 481 *(struct hostent **)rval = NULL; 482 483 switch (af) { 484 case AF_INET: 485 size = INADDRSZ; 486 type = T_A; 487 break; 488 case AF_INET6: 489 size = IN6ADDRSZ; 490 type = T_AAAA; 491 break; 492 default: 493 h_errno = NETDB_INTERNAL; 494 errno = EAFNOSUPPORT; 495 return NS_UNAVAIL; 496 } 497 498 host.h_addrtype = af; 499 host.h_length = size; 500 501 if ((buf = malloc(sizeof(*buf))) == NULL) { 502 h_errno = NETDB_INTERNAL; 503 return NS_NOTFOUND; 504 } 505 n = res_search(name, C_IN, type, buf->buf, sizeof(buf->buf)); 506 if (n < 0) { 507 free(buf); 508 dprintf("res_search failed (%d)\n", n); 509 return (0); 510 } else if (n > sizeof(buf->buf)) { 511 free(buf); 512 dprintf("static buffer is too small (%d)\n", n); 513 return (0); 514 } 515 *(struct hostent **)rval = gethostanswer(buf, n, name, type); 516 free(buf); 517 return (*(struct hostent **)rval != NULL) ? NS_SUCCESS : NS_NOTFOUND; 518} 519 520int 521_dns_gethostbyaddr(void *rval, void *cb_data, va_list ap) 522{ 523 const char *addr; /* XXX should have been def'd as u_char! */ 524 int len, af; 525 const u_char *uaddr; 526 static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff }; 527 static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 }; 528 int n, size; 529 querybuf *buf; 530 struct hostent *hp; 531 char qbuf[MAXDNAME+1], *qp; 532#ifdef SUNSECURITY 533 struct hostent *rhp; 534 char **haddr; 535 u_long old_options; 536 char hname2[MAXDNAME+1]; 537#endif /*SUNSECURITY*/ 538 539 addr = va_arg(ap, const char *); 540 uaddr = (const u_char *)addr; 541 len = va_arg(ap, int); 542 af = va_arg(ap, int); 543 544 *(struct hostent **)rval = NULL; 545 546 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 547 h_errno = NETDB_INTERNAL; 548 return NS_UNAVAIL; 549 } 550 if (af == AF_INET6 && len == IN6ADDRSZ && 551 (!bcmp(uaddr, mapped, sizeof mapped) || 552 !bcmp(uaddr, tunnelled, sizeof tunnelled))) { 553 /* Unmap. */ 554 addr += sizeof mapped; 555 uaddr += sizeof mapped; 556 af = AF_INET; 557 len = INADDRSZ; 558 } 559 switch (af) { 560 case AF_INET: 561 size = INADDRSZ; 562 break; 563 case AF_INET6: 564 size = IN6ADDRSZ; 565 break; 566 default: 567 errno = EAFNOSUPPORT; 568 h_errno = NETDB_INTERNAL; 569 return NS_UNAVAIL; 570 } 571 if (size != len) { 572 errno = EINVAL; 573 h_errno = NETDB_INTERNAL; 574 return NS_UNAVAIL; 575 } 576 switch (af) { 577 case AF_INET: 578 (void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 579 (uaddr[3] & 0xff), 580 (uaddr[2] & 0xff), 581 (uaddr[1] & 0xff), 582 (uaddr[0] & 0xff)); 583 break; 584 case AF_INET6: 585 qp = qbuf; 586 for (n = IN6ADDRSZ - 1; n >= 0; n--) { 587 qp += SPRINTF((qp, "%x.%x.", 588 uaddr[n] & 0xf, 589 (uaddr[n] >> 4) & 0xf)); 590 } 591 strlcat(qbuf, "ip6.arpa", sizeof(qbuf)); 592 break; 593 default: 594 abort(); 595 } 596 if ((buf = malloc(sizeof(*buf))) == NULL) { 597 h_errno = NETDB_INTERNAL; 598 return NS_NOTFOUND; 599 } 600 n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf->buf, sizeof buf->buf); 601 if (n < 0) { 602 free(buf); 603 dprintf("res_query failed (%d)\n", n); 604 return NS_UNAVAIL; 605 } 606 if (n > sizeof buf->buf) { 607 free(buf); 608 dprintf("static buffer is too small (%d)\n", n); 609 return NS_UNAVAIL; 610 } 611 if (!(hp = gethostanswer(buf, n, qbuf, T_PTR))) { 612 free(buf); 613 return NS_NOTFOUND; /* h_errno was set by gethostanswer() */ 614 } 615 free(buf); 616#ifdef SUNSECURITY 617 if (af == AF_INET) { 618 /* 619 * turn off search as the name should be absolute, 620 * 'localhost' should be matched by defnames 621 */ 622 strncpy(hname2, hp->h_name, MAXDNAME); 623 hname2[MAXDNAME] = '\0'; 624 old_options = _res.options; 625 _res.options &= ~RES_DNSRCH; 626 _res.options |= RES_DEFNAMES; 627 if (!(rhp = gethostbyname(hname2))) { 628 syslog(LOG_NOTICE|LOG_AUTH, 629 "gethostbyaddr: No A record for %s (verifying [%s])", 630 hname2, inet_ntoa(*((struct in_addr *)addr))); 631 _res.options = old_options; 632 h_errno = HOST_NOT_FOUND; 633 return NS_NOTFOUND; 634 } 635 _res.options = old_options; 636 for (haddr = rhp->h_addr_list; *haddr; haddr++) 637 if (!memcmp(*haddr, addr, INADDRSZ)) 638 break; 639 if (!*haddr) { 640 syslog(LOG_NOTICE|LOG_AUTH, 641 "gethostbyaddr: A record of %s != PTR record [%s]", 642 hname2, inet_ntoa(*((struct in_addr *)addr))); 643 h_errno = HOST_NOT_FOUND; 644 return NS_NOTFOUND; 645 } 646 } 647#endif /*SUNSECURITY*/ 648 hp->h_addrtype = af; 649 hp->h_length = len; 650 bcopy(addr, host_addr, len); 651 h_addr_ptrs[0] = (char *)host_addr; 652 h_addr_ptrs[1] = NULL; 653 if (af == AF_INET && (_res.options & RES_USE_INET6)) { 654 _map_v4v6_address((char*)host_addr, (char*)host_addr); 655 hp->h_addrtype = AF_INET6; 656 hp->h_length = IN6ADDRSZ; 657 } 658 h_errno = NETDB_SUCCESS; 659 *(struct hostent **)rval = hp; 660 return (hp != NULL) ? NS_SUCCESS : NS_NOTFOUND; 661} 662 663#ifdef RESOLVSORT 664static void 665addrsort(ap, num) 666 char **ap; 667 int num; 668{ 669 int i, j; 670 char **p; 671 short aval[MAXADDRS]; 672 int needsort = 0; 673 674 p = ap; 675 for (i = 0; i < num; i++, p++) { 676 for (j = 0 ; (unsigned)j < _res.nsort; j++) 677 if (_res.sort_list[j].addr.s_addr == 678 (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask)) 679 break; 680 aval[i] = j; 681 if (needsort == 0 && i > 0 && j < aval[i-1]) 682 needsort = i; 683 } 684 if (!needsort) 685 return; 686 687 while (needsort < num) { 688 for (j = needsort - 1; j >= 0; j--) { 689 if (aval[j] > aval[j+1]) { 690 char *hp; 691 692 i = aval[j]; 693 aval[j] = aval[j+1]; 694 aval[j+1] = i; 695 696 hp = ap[j]; 697 ap[j] = ap[j+1]; 698 ap[j+1] = hp; 699 700 } else 701 break; 702 } 703 needsort++; 704 } 705} 706#endif 707void 708_sethostdnsent(stayopen) 709 int stayopen; 710{ 711 if ((_res.options & RES_INIT) == 0 && res_init() == -1) 712 return; 713 if (stayopen) 714 _res.options |= RES_STAYOPEN | RES_USEVC; 715} 716 717void 718_endhostdnsent() 719{ 720 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 721 res_close(); 722} 723