289 lines
7.8 KiB
C
289 lines
7.8 KiB
C
/* 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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/*
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* Copyright (c) 1983, 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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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)getnetbyaddr.c 8.1 (Berkeley) 6/4/93";
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static char sccsid_[] = "from getnetnamadr.c 1.4 (Coimbra) 93/06/03";
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static char rcsid[] = "$Id: getnetnamadr.c,v 8.8 1997/06/01 20:34:37 vixie Exp $";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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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 <stdio.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 <errno.h>
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#include <string.h>
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extern int h_errno;
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#if defined(mips) && defined(SYSTYPE_BSD43)
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extern int errno;
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#endif
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struct netent *_getnetbyaddr __P((long net, int type));
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struct netent *_getnetbyname __P((const char *name));
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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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#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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long al;
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char ac;
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} align;
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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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register HEADER *hp;
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register u_char *cp;
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register int n;
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u_char *eom;
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int type, class, buflen, ancount, qdcount, haveanswer, i, nchar;
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char aux1[30], aux2[30], ans[30], *in, *st, *pauxt, *bp, **ap,
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*paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0;
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static struct netent net_entry;
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static char *net_aliases[MAXALIASES], netbuf[PACKETSZ];
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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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buflen = 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, buflen);
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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)strcpy(&ans[0], bp);
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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, buflen);
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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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bp += strlen(bp) + 1;
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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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aux2[0] = '\0';
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for (i = 0; i < 4; i++) {
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for (st = in, nchar = 0;
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*st != '.';
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st++, nchar++)
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;
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if (nchar != 1 || *in != '0' || flag) {
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flag = 1;
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(void)strncpy(paux1,
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(i==0) ? in : in-1,
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(i==0) ?nchar : nchar+1);
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paux1[(i==0) ? nchar : nchar+1] = '\0';
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pauxt = paux2;
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paux2 = strcat(paux1, paux2);
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paux1 = pauxt;
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}
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in = ++st;
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}
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net_entry.n_net = inet_network(paux2);
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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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struct netent *
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getnetbyaddr(net, net_type)
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register u_long net;
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register int net_type;
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{
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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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if (net_type != AF_INET)
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return (_getnetbyaddr(net, net_type));
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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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anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
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if (anslen < 0) {
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("res_query failed\n");
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#endif
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if (errno == ECONNREFUSED)
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return (_getnetbyaddr(net, net_type));
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return (NULL);
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}
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net_entry = getnetanswer(&buf, anslen, BYADDR);
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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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return (net_entry);
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}
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return (_getnetbyaddr(net, net_type));
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}
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struct netent *
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getnetbyname(net)
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register const char *net;
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{
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int anslen;
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querybuf buf;
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char qbuf[MAXDNAME];
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struct netent *net_entry;
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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 (NULL);
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}
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strcpy(&qbuf[0], net);
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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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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("res_query failed\n");
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#endif
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if (errno == ECONNREFUSED)
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return (_getnetbyname(net));
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return (_getnetbyname(net));
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}
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net_entry = getnetanswer(&buf, anslen, BYNAME);
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if (net_entry)
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return (net_entry);
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return (_getnetbyname(net));
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}
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