a54c3906ad
Do not choke on malformed network addresses. Return n_name in static space, not on the function's stack. MFC after: 1 week
396 lines
10 KiB
C
396 lines
10 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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/* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
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* Dep. Matematica Universidade de Coimbra, Portugal, Europe
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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.
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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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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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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 <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <netdb.h>
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#include <resolv.h>
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#include <ctype.h>
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#include <string.h>
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#include <unistd.h>
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#include <syslog.h>
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#include <stdarg.h>
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#include <nsswitch.h>
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#include "res_config.h"
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extern int h_errno;
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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 MAXPACKET (64*1024)
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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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long al;
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char ac;
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} align;
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/*
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* Reverse the order of first four dotted entries of in.
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* Out must contain space for at least strlen(in) characters.
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* The result does not include any leading 0s of in.
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*/
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static int
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ipreverse(char *in, char *out)
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{
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char *pos[4];
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int len[4];
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char *p, *start;
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int i = 0;
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int leading = 1;
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/* Fill-in element positions and lengths: pos[], len[]. */
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start = p = in;
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for (;;) {
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if (*p == '.' || *p == '\0') {
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/* Leading 0? */
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if (leading && p - start == 1 && *start == '0')
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len[i] = 0;
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else {
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len[i] = p - start;
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leading = 0;
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}
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pos[i] = start;
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start = p + 1;
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i++;
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}
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if (i == 4)
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break;
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if (*p == 0) {
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for (; i < 4; i++) {
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pos[i] = p;
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len[i] = 0;
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}
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break;
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}
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p++;
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}
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/* Copy the entries in reverse order */
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p = out;
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leading = 1;
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for (i = 3; i >= 0; i--) {
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memcpy(p, pos[i], len[i]);
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if (len[i])
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leading = 0;
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p += len[i];
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/* Need a . separator? */
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if (!leading && i > 0 && len[i - 1])
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*p++ = '.';
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}
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*p = '\0';
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}
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static struct netent *
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getnetanswer(answer, anslen, net_i)
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querybuf *answer;
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int anslen;
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int net_i;
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{
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HEADER *hp;
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u_char *cp;
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int n;
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u_char *eom;
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int type, class, ancount, qdcount, haveanswer, i, nchar;
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char aux[MAXHOSTNAMELEN];
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char *in, *bp, *ep, **ap;
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static struct netent net_entry;
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static char *net_aliases[MAXALIASES], netbuf[PACKETSZ];
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static char ans[MAXHOSTNAMELEN];
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/*
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* find first satisfactory answer
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*
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* answer --> +------------+ ( MESSAGE )
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* | Header |
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* +------------+
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* | Question | the question for the name server
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* +------------+
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* | Answer | RRs answering the question
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* +------------+
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* | Authority | RRs pointing toward an authority
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* | Additional | RRs holding additional information
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* +------------+
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*/
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eom = answer->buf + anslen;
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hp = &answer->hdr;
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ancount = ntohs(hp->ancount); /* #/records in the answer section */
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qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
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bp = netbuf;
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ep = netbuf + sizeof(netbuf);
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cp = answer->buf + HFIXEDSZ;
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if (!qdcount) {
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if (hp->aa)
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h_errno = HOST_NOT_FOUND;
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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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while (qdcount-- > 0)
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cp += __dn_skipname(cp, eom) + QFIXEDSZ;
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ap = net_aliases;
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*ap = NULL;
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net_entry.n_aliases = net_aliases;
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haveanswer = 0;
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while (--ancount >= 0 && cp < eom) {
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n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
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if ((n < 0) || !res_dnok(bp))
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break;
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cp += n;
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ans[0] = '\0';
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(void)strncpy(&ans[0], bp, sizeof(ans) - 1);
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ans[sizeof(ans) - 1] = '\0';
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GETSHORT(type, cp);
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GETSHORT(class, cp);
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cp += INT32SZ; /* TTL */
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GETSHORT(n, cp);
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if (class == C_IN && type == T_PTR) {
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n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
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if ((n < 0) || !res_hnok(bp)) {
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cp += n;
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return (NULL);
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}
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cp += n;
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*ap++ = bp;
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n = strlen(bp) + 1;
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bp += n;
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net_entry.n_addrtype =
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(class == C_IN) ? AF_INET : AF_UNSPEC;
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haveanswer++;
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}
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}
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if (haveanswer) {
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*ap = NULL;
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switch (net_i) {
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case BYADDR:
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net_entry.n_name = *net_entry.n_aliases;
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net_entry.n_net = 0L;
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break;
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case BYNAME:
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in = *net_entry.n_aliases;
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net_entry.n_name = &ans[0];
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if (strlen(in) + 1 > sizeof(aux)) {
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h_errno = NETDB_INTERNAL;
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errno = ENOBUFS;
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return (NULL);
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}
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ipreverse(in, aux);
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net_entry.n_net = inet_network(aux);
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break;
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}
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net_entry.n_aliases++;
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return (&net_entry);
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}
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h_errno = TRY_AGAIN;
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return (NULL);
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}
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int
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_dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
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{
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unsigned long net;
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int net_type;
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unsigned int netbr[4];
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int nn, anslen;
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querybuf *buf;
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char qbuf[MAXDNAME];
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unsigned long net2;
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struct netent *net_entry;
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net = va_arg(ap, unsigned long);
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net_type = va_arg(ap, int);
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*(struct netent **)rval = NULL;
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if (net_type != AF_INET)
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return NS_UNAVAIL;
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for (nn = 4, net2 = net; net2; net2 >>= 8)
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netbr[--nn] = net2 & 0xff;
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switch (nn) {
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case 3: /* Class A */
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sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
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break;
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case 2: /* Class B */
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sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
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break;
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case 1: /* Class C */
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sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
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netbr[1]);
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break;
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case 0: /* Class D - E */
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sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
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netbr[1], netbr[0]);
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break;
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}
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if ((buf = malloc(sizeof(*buf))) == NULL) {
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h_errno = NETDB_INTERNAL;
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return NS_NOTFOUND;
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}
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anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
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if (anslen < 0) {
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free(buf);
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("res_search failed\n");
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#endif
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return NS_UNAVAIL;
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} else if (anslen > sizeof(*buf)) {
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free(buf);
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("res_search static buffer too small\n");
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#endif
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return NS_UNAVAIL;
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}
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net_entry = getnetanswer(buf, anslen, BYADDR);
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free(buf);
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if (net_entry) {
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unsigned u_net = net; /* maybe net should be unsigned ? */
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/* Strip trailing zeros */
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while ((u_net & 0xff) == 0 && u_net != 0)
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u_net >>= 8;
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net_entry->n_net = u_net;
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*(struct netent **)rval = net_entry;
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return NS_SUCCESS;
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}
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return NS_NOTFOUND;
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}
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int
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_dns_getnetbyname(void *rval, void *cb_data, va_list ap)
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{
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const char *net;
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int anslen;
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querybuf *buf;
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char qbuf[MAXDNAME];
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net = va_arg(ap, const char *);
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*(struct netent**)rval = NULL;
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if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
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h_errno = NETDB_INTERNAL;
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return NS_UNAVAIL;
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}
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if ((buf = malloc(sizeof(*buf))) == NULL) {
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h_errno = NETDB_INTERNAL;
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return NS_NOTFOUND;
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}
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strncpy(qbuf, net, sizeof(qbuf) - 1);
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qbuf[sizeof(qbuf) - 1] = '\0';
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anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
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if (anslen < 0) {
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free(buf);
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("res_search failed\n");
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#endif
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return NS_UNAVAIL;
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} else if (anslen > sizeof(*buf)) {
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free(buf);
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("res_search static buffer too small\n");
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#endif
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return NS_UNAVAIL;
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}
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*(struct netent**)rval = getnetanswer(buf, anslen, BYNAME);
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free(buf);
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return (*(struct netent**)rval != NULL) ? NS_SUCCESS : NS_NOTFOUND;
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}
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void
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_setnetdnsent(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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_endnetdnsent()
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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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