40569757cc
incredibly obnoxious, but also makes inverse mappings work when the local resolver is in a cache-only configuration. (Maybe this is actually a bug in BIND?)
478 lines
12 KiB
C
478 lines
12 KiB
C
/*-
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* Copyright (c) 1985, 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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* -
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* Portions Copyright (c) 1993 by Digital Equipment Corporation.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies, and that
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* the name of Digital Equipment Corporation not be used in advertising or
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* publicity pertaining to distribution of the document or software without
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* specific, written prior permission.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
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* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
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* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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* -
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* --Copyright--
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93";
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static char rcsid[] = "$Id: gethostbydns.c,v 1.2 1994/09/25 17:45:37 pst Exp $";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <netdb.h>
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#include <resolv.h>
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#include <stdio.h>
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#include <ctype.h>
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#include <errno.h>
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#include <string.h>
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#include <syslog.h>
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#define BYADDR 0
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#define BYNAME 1
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#define MAXALIASES 35
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#define MAXADDRS 35
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#define MULTI_PTRS_ARE_ALIASES 1 /* XXX - experimental */
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static const char AskedForGot[] =
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"gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
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static char *h_addr_ptrs[MAXADDRS + 1];
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static struct hostent host;
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static char *host_aliases[MAXALIASES];
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static char hostbuf[8*1024];
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static struct in_addr host_addr;
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static FILE *hostf = NULL;
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static char hostaddr[MAXADDRS];
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static char *host_addrs[2];
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static int stayopen = 0;
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#if PACKETSZ > 1024
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#define MAXPACKET PACKETSZ
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#else
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#define MAXPACKET 1024
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#endif
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typedef union {
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HEADER hdr;
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u_char buf[MAXPACKET];
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} querybuf;
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typedef union {
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int32_t al;
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char ac;
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} align;
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extern int h_errno;
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#ifdef RESOLVSORT
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static void
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addrsort(ap, num)
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char **ap;
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int num;
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{
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int i, j;
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char **p;
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short aval[MAXADDRS];
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int needsort = 0;
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p = ap;
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for (i = 0; i < num; i++, p++) {
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for (j = 0 ; j < _res.nsort; j++)
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if (_res.sort_list[j].addr.s_addr ==
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(((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
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break;
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aval[i] = j;
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if (needsort == 0 && i > 0 && j < aval[i-1])
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needsort = i;
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}
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if (!needsort)
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return;
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while (needsort < num) {
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for (j = needsort - 1; j >= 0; j--) {
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if (aval[j] > aval[j+1]) {
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char *hp;
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i = aval[j];
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aval[j] = aval[j+1];
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aval[j+1] = i;
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hp = ap[j];
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ap[j] = ap[j+1];
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ap[j+1] = hp;
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} else
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break;
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}
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needsort++;
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}
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}
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#endif
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static struct hostent *
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gethostanswer(answer, anslen, qname, qclass, qtype)
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const querybuf *answer;
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int anslen;
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const char *qname;
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int qclass, qtype;
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{
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register const HEADER *hp;
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register const u_char *cp;
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register int n;
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const u_char *eom;
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char *bp, **ap, **hap;
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int type, class, buflen, ancount, qdcount;
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int haveanswer, had_error;
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int toobig = 0;
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char tbuf[MAXDNAME+1];
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host.h_name = NULL;
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eom = answer->buf + anslen;
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/*
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* find first satisfactory answer
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*/
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hp = &answer->hdr;
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ancount = ntohs(hp->ancount);
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qdcount = ntohs(hp->qdcount);
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bp = hostbuf;
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buflen = sizeof hostbuf;
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cp = answer->buf + HFIXEDSZ;
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if (qdcount != 1) {
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h_errno = NO_RECOVERY;
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return (NULL);
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}
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if ((n = dn_expand(answer->buf, eom, cp, bp, buflen)) < 0) {
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h_errno = NO_RECOVERY;
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return (NULL);
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}
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cp += n + QFIXEDSZ;
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if (qtype == T_A) {
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/* res_send() has already verified that the query name is the
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* same as the one we sent; this just gets the expanded name
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* (i.e., with the succeeding search-domain tacked on).
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*/
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n = strlen(bp) + 1; /* for the \0 */
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host.h_name = bp;
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bp += n;
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buflen -= n;
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/* The qname can be abbreviated, but h_name is now absolute. */
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qname = host.h_name;
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}
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ap = host_aliases;
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*ap = NULL;
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host.h_aliases = host_aliases;
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hap = h_addr_ptrs;
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*hap = NULL;
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host.h_addr_list = h_addr_ptrs;
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haveanswer = 0;
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had_error = 0;
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while (ancount-- > 0 && cp < eom && !had_error) {
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n = dn_expand(answer->buf, eom, cp, bp, buflen);
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if (n < 0) {
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had_error++;
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continue;
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}
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cp += n; /* name */
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type = _getshort(cp);
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cp += INT16SZ; /* type */
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class = _getshort(cp);
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cp += INT16SZ + INT32SZ; /* class, TTL */
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n = _getshort(cp);
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cp += INT16SZ; /* len */
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if (class != qclass) {
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/* XXX - debug? syslog? */
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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if (qtype == T_A && type == T_CNAME) {
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if (ap >= &host_aliases[MAXALIASES-1])
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continue;
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n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
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if (n < 0) {
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had_error++;
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continue;
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}
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cp += n;
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if (host.h_name && strcasecmp(host.h_name, bp) != 0) {
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syslog(LOG_NOTICE|LOG_AUTH,
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"gethostby*.getanswer: asked for \"%s\", got CNAME for \"%s\"",
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host.h_name, bp);
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continue; /* XXX - had_error++ ? */
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}
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/* Store alias. */
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*ap++ = bp;
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n = strlen(bp) + 1; /* for the \0 */
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bp += n;
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buflen -= n;
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/* Get canonical name. */
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n = strlen(tbuf) + 1; /* for the \0 */
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if (n > buflen) {
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had_error++;
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continue;
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}
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strcpy(bp, tbuf);
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host.h_name = bp;
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bp += n;
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buflen -= n;
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continue;
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}
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if (type != qtype) {
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syslog(LOG_NOTICE|LOG_AUTH,
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"gethostby*.getanswer: asked for type %d(%s), got %d(%s)",
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qtype, qname, type, bp);
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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switch (type) {
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case T_PTR:
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if (strcasecmp(qname, bp) != 0) {
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syslog(LOG_NOTICE|LOG_AUTH,
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AskedForGot, qname, bp);
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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n = dn_expand(answer->buf, eom, cp, bp, buflen);
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if (n < 0) {
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had_error++;
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break;
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}
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#if MULTI_PTRS_ARE_ALIASES
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cp += n;
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if (!haveanswer)
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host.h_name = bp;
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else if (ap < &host_aliases[MAXALIASES-1])
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*ap++ = bp;
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else
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n = -1;
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if (n != -1) {
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n = strlen(bp) + 1; /* for the \0 */
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bp += n;
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buflen -= n;
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}
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break;
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#else
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host.h_name = bp;
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return (&host);
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#endif
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case T_A:
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if (strcasecmp(host.h_name, bp) != 0) {
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syslog(LOG_NOTICE|LOG_AUTH,
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AskedForGot, host.h_name, bp);
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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if (haveanswer) {
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if (n != host.h_length) {
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cp += n;
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continue;
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}
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} else {
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register int nn;
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host.h_length = n;
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host.h_addrtype = (class == C_IN)
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? AF_INET
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: AF_UNSPEC;
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host.h_name = bp;
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nn = strlen(bp) + 1; /* for the \0 */
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bp += nn;
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buflen -= nn;
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}
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bp += sizeof(align) - ((u_long)bp % sizeof(align));
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if (bp + n >= &hostbuf[sizeof hostbuf]) {
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if (_res.options & RES_DEBUG)
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printf("size (%d) too big\n", n);
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had_error++;
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continue;
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}
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if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
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if (_res.options & RES_DEBUG && !toobig++)
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printf("Too many addresses (%d)\n",
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MAXADDRS);
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cp += n;
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continue;
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}
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bcopy(cp, *hap++ = bp, n);
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bp += n;
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cp += n;
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break;
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default:
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abort();
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} /*switch*/
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if (!had_error)
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haveanswer++;
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} /*while*/
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if (haveanswer) {
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*ap = NULL;
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*hap = NULL;
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# if defined(RESOLVSORT)
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/*
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* Note: we sort even if host can take only one address
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* in its return structures - should give it the "best"
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* address in that case, not some random one
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*/
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if (_res.nsort && haveanswer > 1 &&
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qclass == C_IN && qtype == T_A)
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addrsort(h_addr_ptrs, haveanswer);
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# endif /*RESOLVSORT*/
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if (!host.h_name) {
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n = strlen(qname) + 1; /* for the \0 */
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strcpy(bp, qname);
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host.h_name = bp;
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}
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return (&host);
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} else {
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h_errno = TRY_AGAIN;
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return (NULL);
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}
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}
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struct hostent *
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_gethostbydnsname(name)
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const char *name;
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{
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querybuf buf;
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register const char *cp;
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int n;
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/*
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* disallow names consisting only of digits/dots, unless
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* they end in a dot.
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*/
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if (isdigit(name[0]))
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for (cp = name;; ++cp) {
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if (!*cp) {
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if (*--cp == '.')
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break;
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/*
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* All-numeric, no dot at the end.
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* Fake up a hostent as if we'd actually
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* done a lookup.
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*/
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if (!inet_aton(name, &host_addr)) {
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h_errno = HOST_NOT_FOUND;
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return (NULL);
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}
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host.h_name = (char *)name;
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host.h_aliases = host_aliases;
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host_aliases[0] = NULL;
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host.h_addrtype = AF_INET;
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host.h_length = INT32SZ;
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h_addr_ptrs[0] = (char *)&host_addr;
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h_addr_ptrs[1] = NULL;
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host.h_addr_list = h_addr_ptrs;
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return (&host);
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}
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if (!isdigit(*cp) && *cp != '.')
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break;
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}
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if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) {
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if (_res.options & RES_DEBUG)
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printf("res_search failed\n");
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return (NULL);
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}
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return (gethostanswer(&buf, n, name, C_IN, T_A));
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}
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struct hostent *
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_gethostbydnsaddr(addr, len, type)
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const char *addr;
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int len, type;
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{
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int n;
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querybuf buf;
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register struct hostent *hp;
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char qbuf[MAXDNAME+1];
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int o_res_options = _res.options;
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if (type != AF_INET)
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return (NULL);
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(void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
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((unsigned)addr[3] & 0xff),
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((unsigned)addr[2] & 0xff),
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((unsigned)addr[1] & 0xff),
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((unsigned)addr[0] & 0xff));
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_res.options |= RES_RECURSE;
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n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
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_res.options = o_res_options;
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if (n < 0) {
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if (_res.options & RES_DEBUG)
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printf("res_query failed\n");
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return (NULL);
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}
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if (!(hp = gethostanswer(&buf, n, qbuf, C_IN, T_PTR)))
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return (NULL);
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hp->h_addrtype = type;
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hp->h_length = len;
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h_addr_ptrs[0] = (char *)&host_addr;
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h_addr_ptrs[1] = NULL;
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host_addr = *(struct in_addr *)addr;
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#if BSD < 43 && !defined(h_addr) /* new-style hostent structure */
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hp->h_addr = h_addr_ptrs[0];
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#endif
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return (hp);
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}
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void
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_sethostdnsent(stayopen)
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int stayopen;
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{
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if (stayopen)
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_res.options |= RES_STAYOPEN | RES_USEVC;
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}
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void
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_endhostdnsent()
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|
{
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_res.options &= ~(RES_STAYOPEN | RES_USEVC);
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_res_close();
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}
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