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** dns_hosts.c DNS/Hesiod Hosts map access routines
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** Copyright (c) 1993 Signum Support AB, Sweden
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** This file is part of the NYS Library.
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** The NYS Library is free software; you can redistribute it and/or
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** modify it under the terms of the GNU Library General Public License as
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** published by the Free Software Foundation; either version 2 of the
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** License, or (at your option) any later version.
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** The NYS Library is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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** Library General Public License for more details.
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** You should have received a copy of the GNU Library General Public
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** License along with the NYS Library; see the file COPYING.LIB. If
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** not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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** Cambridge, MA 02139, USA.
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** This file contains software derived from the gethostnamadr.c file
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** from lib/libc/net/ in the 4.3BSD NET.2 distribution:
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** Copyright (c) 1985, 1988 Regents of the University of California.
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** All rights reserved.
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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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** 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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** 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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#if defined(HAVE_CONFIG_H)
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#if defined(linux) && !defined(HAVE__DNS_GETHOSTBYNAME) && !defined(HAVE_RES_GETHOSTBYNAME) && !defined(HAVE___NSS_CONFIGURE_LOOKUP)
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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 "res_options.h"
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extern void _res_close(void);
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extern struct hostent *_gethtbyaddr(const char *, int, int);
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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*.getanswer: 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 void addrsort __P((char **, int));
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#define MAXPACKET PACKETSZ
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#define MAXPACKET 1024
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u_char buf[MAXPACKET];
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# define dprintf(msg, num) /*nada*/
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static struct hostent *
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getanswer(const querybuf *answer, int anslen, const char *qname, int qclass, int qtype)
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register const HEADER *hp;
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register const u_char *cp;
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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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char tbuf[MAXDNAME+1];
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eom = answer->buf + anslen;
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* find first satisfactory answer
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ancount = ntohs(hp->ancount);
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qdcount = ntohs(hp->qdcount);
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buflen = sizeof hostbuf;
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cp = answer->buf + HFIXEDSZ;
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h_errno = NO_RECOVERY;
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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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/* 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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n = strlen(bp) + 1; /* for the \0 */
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/* The qname can be abbreviated, but h_name is now absolute. */
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host.h_aliases = host_aliases;
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host.h_addr_list = h_addr_ptrs;
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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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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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cp += INT16SZ; /* len */
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if (class != qclass) {
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/* XXX - debug? syslog? */
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continue; /* XXX - had_error++ ? */
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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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n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
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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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continue; /* XXX - had_error++ ? */
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n = strlen(bp) + 1; /* for the \0 */
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/* Get canonical name. */
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n = strlen(tbuf) + 1; /* for the \0 */
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syslog(LOG_NOTICE|LOG_AUTH,
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"gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
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qname, p_class(qclass), p_type(qtype),
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continue; /* XXX - had_error++ ? */
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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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continue; /* XXX - had_error++ ? */
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n = dn_expand(answer->buf, eom, cp, bp, buflen);
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#if MULTI_PTRS_ARE_ALIASES
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else if (ap < &host_aliases[MAXALIASES-1])
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n = strlen(bp) + 1; /* for the \0 */
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h_errno = NETDB_SUCCESS;
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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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continue; /* XXX - had_error++ ? */
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if (n != host.h_length) {
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host.h_addrtype = (class == C_IN)
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nn = strlen(bp) + 1; /* for the \0 */
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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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dprintf("size (%d) too big\n", n);
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if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
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dprintf("Too many addresses (%d)\n",
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bcopy(cp, *hap++ = bp, n);
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dprintf("Impossible condition (type=%d)\n", type);
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h_errno = NO_RECOVERY;
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# if defined(RESOLVSORT)
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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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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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n = strlen(qname) + 1; /* for the \0 */
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h_errno = NETDB_SUCCESS;
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addrsort(char **ap, int num)
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short aval[MAXADDRS];
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for (i = 0; i < num; i++, p++) {
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for (j = 0 ; (unsigned)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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if (needsort == 0 && i > 0 && j < aval[i-1])
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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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_dns_gethostbyname(const char *name)
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register const char *cp;
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* if there aren't any dots, it could be a user-level alias.
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* this is also done in res_query() since we are not the only
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* function that looks up host names.
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if (!strchr(name, '.') && (cp = __hostalias(name)))
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* disallow names consisting only of digits/dots, unless
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if (isdigit(name[0]))
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for (cp = name;; ++cp) {
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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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if (!inet_aton(name, &host_addr)) {
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h_errno = HOST_NOT_FOUND;
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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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h_errno = NETDB_SUCCESS;
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if (!isdigit(*cp) && *cp != '.')
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if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) {
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dprintf("res_search failed (%d)\n", n);
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return (getanswer(&buf, n, name, C_IN, T_A));
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_dns_gethostbyaddr(const char *addr, int len, int type)
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register struct hostent *hp;
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char qbuf[MAXDNAME+1];
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register struct hostent *rhp;
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char hname2[MAXDNAME+1];
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#endif /*SUNSECURITY*/
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if (type != AF_INET) {
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errno = EAFNOSUPPORT;
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h_errno = NETDB_INTERNAL;
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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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n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
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dprintf("res_query failed (%d)\n", n);
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if (!(hp = getanswer(&buf, n, qbuf, C_IN, T_PTR)))
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return (NULL); /* h_errno was set by getanswer() */
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* turn off search as the name should be absolute,
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* 'localhost' should be matched by defnames
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strncpy(hname2, hp->h_name, MAXDNAME);
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hname2[MAXDNAME] = '\0';
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old_options = _res.options;
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_res.options &= ~RES_DNSRCH;
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_res.options |= RES_DEFNAMES;
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if (!(rhp = gethostbyname(hp->h_name))) {
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syslog(LOG_NOTICE|LOG_AUTH,
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"gethostbyaddr: No A record for %s (verifying [%s])",
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hname2, inet_ntoa(*((struct in_addr *)addr)));
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_res.options = old_options;
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h_errno = HOST_NOT_FOUND;
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_res.options = old_options;
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for (haddr = rhp->h_addr_list; *haddr; haddr++)
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if (!memcmp(*haddr, addr, INADDRSZ))
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syslog(LOG_NOTICE|LOG_AUTH,
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"gethostbyaddr: A record of %s != PTR record [%s]",
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hname2, inet_ntoa(*((struct in_addr *)addr)));
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h_errno = HOST_NOT_FOUND;
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#endif /*SUNSECURITY*/
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hp->h_addrtype = type;
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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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h_errno = NETDB_SUCCESS;
added
removed
ypbind-mt-1.19/lib/dns_hosts.c
