928 lines
23 KiB
C
928 lines
23 KiB
C
/*
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* Copyright (c) 1985, 1989, 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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/*
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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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/*
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* Portions Copyright (c) 1996 by Internet Software Consortium.
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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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* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM 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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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
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static char orig_rcsid[] = "From: Id: res_send.c,v 8.20 1998/04/06 23:27:51 halley Exp $";
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static char rcsid[] = "$FreeBSD$";
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#endif /* LIBC_SCCS and not lint */
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/*
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* Send query to name server and wait for reply.
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*/
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/socket.h>
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#include <sys/uio.h>
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#include <arpa/inet.h>
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#include <errno.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 <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <poll.h>
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#include "res_config.h"
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#ifdef NOPOLL /* libc_r doesn't wrap poll yet() */
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static int use_poll = 0;
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#else
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static int use_poll = 1; /* adapt to poll() syscall availability */
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/* 0 = not present, 1 = try it, 2 = exists */
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#endif
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static int s = -1; /* socket used for communications */
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static int connected = 0; /* is the socket connected */
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static int vc = 0; /* is the socket a virtual circuit? */
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static res_send_qhook Qhook = NULL;
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static res_send_rhook Rhook = NULL;
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#define CAN_RECONNECT 1
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#ifndef DEBUG
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# define Dprint(cond, args) /*empty*/
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# define DprintQ(cond, args, query, size) /*empty*/
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# define Aerror(file, string, error, address) /*empty*/
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# define Perror(file, string, error) /*empty*/
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#else
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# define Dprint(cond, args) if (cond) {fprintf args;} else {}
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# define DprintQ(cond, args, query, size) if (cond) {\
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fprintf args;\
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__fp_nquery(query, size, stdout);\
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} else {}
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static void
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Aerror(file, string, error, address)
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FILE *file;
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char *string;
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int error;
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struct sockaddr_in address;
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{
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int save = errno;
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if (_res.options & RES_DEBUG) {
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fprintf(file, "res_send: %s ([%s].%u): %s\n",
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string,
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inet_ntoa(address.sin_addr),
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ntohs(address.sin_port),
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strerror(error));
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}
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errno = save;
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}
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static void
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Perror(file, string, error)
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FILE *file;
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char *string;
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int error;
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{
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int save = errno;
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if (_res.options & RES_DEBUG) {
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fprintf(file, "res_send: %s: %s\n",
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string, strerror(error));
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}
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errno = save;
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}
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#endif
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void
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res_send_setqhook(hook)
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res_send_qhook hook;
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{
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Qhook = hook;
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}
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void
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res_send_setrhook(hook)
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res_send_rhook hook;
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{
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Rhook = hook;
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}
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/* int
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* res_isourserver(ina)
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* looks up "ina" in _res.ns_addr_list[]
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* returns:
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* 0 : not found
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* >0 : found
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* author:
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* paul vixie, 29may94
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*/
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int
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res_isourserver(inp)
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const struct sockaddr_in *inp;
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{
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struct sockaddr_in ina;
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int ns, ret;
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ina = *inp;
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ret = 0;
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for (ns = 0; ns < _res.nscount; ns++) {
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const struct sockaddr_in *srv = &_res.nsaddr_list[ns];
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if (srv->sin_family == ina.sin_family &&
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srv->sin_port == ina.sin_port &&
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(srv->sin_addr.s_addr == INADDR_ANY ||
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srv->sin_addr.s_addr == ina.sin_addr.s_addr)) {
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ret++;
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break;
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}
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}
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return (ret);
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}
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/* int
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* res_nameinquery(name, type, class, buf, eom)
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* look for (name,type,class) in the query section of packet (buf,eom)
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* requires:
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* buf + HFIXEDSZ <= eom
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* returns:
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* -1 : format error
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* 0 : not found
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* >0 : found
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* author:
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* paul vixie, 29may94
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*/
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int
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res_nameinquery(name, type, class, buf, eom)
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const char *name;
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int type, class;
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const u_char *buf, *eom;
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{
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const u_char *cp = buf + HFIXEDSZ;
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int qdcount = ntohs(((HEADER*)buf)->qdcount);
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while (qdcount-- > 0) {
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char tname[MAXDNAME+1];
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int n, ttype, tclass;
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n = dn_expand(buf, eom, cp, tname, sizeof tname);
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if (n < 0)
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return (-1);
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cp += n;
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if (cp + 2 * INT16SZ > eom)
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return (-1);
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ttype = ns_get16(cp); cp += INT16SZ;
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tclass = ns_get16(cp); cp += INT16SZ;
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if (ttype == type &&
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tclass == class &&
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strcasecmp(tname, name) == 0)
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return (1);
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}
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return (0);
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}
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/* int
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* res_queriesmatch(buf1, eom1, buf2, eom2)
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* is there a 1:1 mapping of (name,type,class)
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* in (buf1,eom1) and (buf2,eom2)?
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* returns:
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* -1 : format error
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* 0 : not a 1:1 mapping
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* >0 : is a 1:1 mapping
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* author:
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* paul vixie, 29may94
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*/
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int
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res_queriesmatch(buf1, eom1, buf2, eom2)
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const u_char *buf1, *eom1;
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const u_char *buf2, *eom2;
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{
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const u_char *cp = buf1 + HFIXEDSZ;
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int qdcount = ntohs(((HEADER*)buf1)->qdcount);
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if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
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return (-1);
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/*
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* Only header section present in replies to
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* dynamic update packets.
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*/
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if ( (((HEADER *)buf1)->opcode == ns_o_update) &&
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(((HEADER *)buf2)->opcode == ns_o_update) )
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return (1);
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if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
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return (0);
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while (qdcount-- > 0) {
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char tname[MAXDNAME+1];
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int n, ttype, tclass;
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n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
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if (n < 0)
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return (-1);
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cp += n;
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if (cp + 2 * INT16SZ > eom1)
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return (-1);
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ttype = ns_get16(cp); cp += INT16SZ;
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tclass = ns_get16(cp); cp += INT16SZ;
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if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
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return (0);
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}
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return (1);
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}
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int
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res_send(buf, buflen, ans, anssiz)
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const u_char *buf;
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int buflen;
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u_char *ans;
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int anssiz;
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{
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HEADER *hp = (HEADER *) buf;
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HEADER *anhp = (HEADER *) ans;
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int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns, n;
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u_int badns; /* XXX NSMAX can't exceed #/bits in this variable */
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if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
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/* errno should have been set by res_init() in this case. */
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return (-1);
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}
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if (anssiz < HFIXEDSZ) {
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errno = EINVAL;
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return (-1);
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}
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DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),
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(stdout, ";; res_send()\n"), buf, buflen);
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v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
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gotsomewhere = 0;
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connreset = 0;
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terrno = ETIMEDOUT;
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badns = 0;
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/*
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* Send request, RETRY times, or until successful
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*/
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for (try = 0; try < _res.retry; try++) {
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for (ns = 0; ns < _res.nscount; ns++) {
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struct sockaddr_in *nsap = &_res.nsaddr_list[ns];
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same_ns:
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if (badns & (1 << ns)) {
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res_close();
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goto next_ns;
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}
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if (Qhook) {
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int done = 0, loops = 0;
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do {
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res_sendhookact act;
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act = (*Qhook)(&nsap, &buf, &buflen,
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ans, anssiz, &resplen);
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switch (act) {
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case res_goahead:
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done = 1;
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break;
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case res_nextns:
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res_close();
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goto next_ns;
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case res_done:
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return (resplen);
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case res_modified:
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/* give the hook another try */
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if (++loops < 42) /*doug adams*/
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break;
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/*FALLTHROUGH*/
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case res_error:
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/*FALLTHROUGH*/
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default:
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return (-1);
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}
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} while (!done);
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}
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|
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Dprint(_res.options & RES_DEBUG,
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(stdout, ";; Querying server (# %d) address = %s\n",
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ns + 1, inet_ntoa(nsap->sin_addr)));
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|
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if (v_circuit) {
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int truncated;
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struct iovec iov[2];
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u_short len;
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u_char *cp;
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|
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/*
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* Use virtual circuit;
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* at most one attempt per server.
|
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*/
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try = _res.retry;
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truncated = 0;
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if (s < 0 || !vc || hp->opcode == ns_o_update) {
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if (s >= 0)
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res_close();
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|
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s = socket(PF_INET, SOCK_STREAM, 0);
|
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if (s < 0) {
|
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terrno = errno;
|
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Perror(stderr, "socket(vc)", errno);
|
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return (-1);
|
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}
|
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errno = 0;
|
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if (connect(s, (struct sockaddr *)nsap,
|
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sizeof *nsap) < 0) {
|
|
terrno = errno;
|
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Aerror(stderr, "connect/vc",
|
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errno, *nsap);
|
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badns |= (1 << ns);
|
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res_close();
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goto next_ns;
|
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}
|
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vc = 1;
|
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}
|
|
/*
|
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* Send length & message
|
|
*/
|
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putshort((u_short)buflen, (u_char*)&len);
|
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iov[0].iov_base = (caddr_t)&len;
|
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iov[0].iov_len = INT16SZ;
|
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iov[1].iov_base = (caddr_t)buf;
|
|
iov[1].iov_len = buflen;
|
|
if (writev(s, iov, 2) != (INT16SZ + buflen)) {
|
|
terrno = errno;
|
|
Perror(stderr, "write failed", errno);
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
/*
|
|
* Receive length & response
|
|
*/
|
|
read_len:
|
|
cp = ans;
|
|
len = INT16SZ;
|
|
while ((n = _read(s, (char *)cp, (int)len)) > 0) {
|
|
cp += n;
|
|
if ((len -= n) <= 0)
|
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break;
|
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}
|
|
if (n <= 0) {
|
|
terrno = errno;
|
|
Perror(stderr, "read failed", errno);
|
|
res_close();
|
|
/*
|
|
* A long running process might get its TCP
|
|
* connection reset if the remote server was
|
|
* restarted. Requery the server instead of
|
|
* trying a new one. When there is only one
|
|
* server, this means that a query might work
|
|
* instead of failing. We only allow one reset
|
|
* per query to prevent looping.
|
|
*/
|
|
if (terrno == ECONNRESET && !connreset) {
|
|
connreset = 1;
|
|
res_close();
|
|
goto same_ns;
|
|
}
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
resplen = ns_get16(ans);
|
|
if (resplen > anssiz) {
|
|
Dprint(_res.options & RES_DEBUG,
|
|
(stdout, ";; response truncated\n")
|
|
);
|
|
truncated = 1;
|
|
len = anssiz;
|
|
} else
|
|
len = resplen;
|
|
if (len < HFIXEDSZ) {
|
|
/*
|
|
* Undersized message.
|
|
*/
|
|
Dprint(_res.options & RES_DEBUG,
|
|
(stdout, ";; undersized: %d\n", len));
|
|
terrno = EMSGSIZE;
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
cp = ans;
|
|
while (len != 0 &&
|
|
(n = _read(s, (char *)cp, (int)len)) > 0) {
|
|
cp += n;
|
|
len -= n;
|
|
}
|
|
if (n <= 0) {
|
|
terrno = errno;
|
|
Perror(stderr, "read(vc)", errno);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
if (truncated) {
|
|
/*
|
|
* Flush rest of answer
|
|
* so connection stays in synch.
|
|
*/
|
|
anhp->tc = 1;
|
|
len = resplen - anssiz;
|
|
while (len != 0) {
|
|
char junk[PACKETSZ];
|
|
|
|
n = (len > sizeof(junk)
|
|
? sizeof(junk)
|
|
: len);
|
|
if ((n = _read(s, junk, n)) > 0)
|
|
len -= n;
|
|
else
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* The calling applicating has bailed out of
|
|
* a previous call and failed to arrange to have
|
|
* the circuit closed or the server has got
|
|
* itself confused. Anyway drop the packet and
|
|
* wait for the correct one.
|
|
*/
|
|
if (hp->id != anhp->id) {
|
|
DprintQ((_res.options & RES_DEBUG) ||
|
|
(_res.pfcode & RES_PRF_REPLY),
|
|
(stdout, ";; old answer (unexpected):\n"),
|
|
ans, (resplen>anssiz)?anssiz:resplen);
|
|
goto read_len;
|
|
}
|
|
} else {
|
|
/*
|
|
* Use datagrams.
|
|
*/
|
|
#ifndef NOPOLL
|
|
struct pollfd pfd;
|
|
int msec;
|
|
#endif
|
|
struct timeval timeout;
|
|
fd_set dsmask, *dsmaskp;
|
|
int dsmasklen;
|
|
struct sockaddr_in from;
|
|
int fromlen;
|
|
|
|
if ((s < 0) || vc) {
|
|
if (vc)
|
|
res_close();
|
|
s = socket(PF_INET, SOCK_DGRAM, 0);
|
|
if (s < 0) {
|
|
#ifndef CAN_RECONNECT
|
|
bad_dg_sock:
|
|
#endif
|
|
terrno = errno;
|
|
Perror(stderr, "socket(dg)", errno);
|
|
return (-1);
|
|
}
|
|
connected = 0;
|
|
}
|
|
#ifndef CANNOT_CONNECT_DGRAM
|
|
/*
|
|
* On a 4.3BSD+ machine (client and server,
|
|
* actually), sending to a nameserver datagram
|
|
* port with no nameserver will cause an
|
|
* ICMP port unreachable message to be returned.
|
|
* If our datagram socket is "connected" to the
|
|
* server, we get an ECONNREFUSED error on the next
|
|
* socket operation, and select returns if the
|
|
* error message is received. We can thus detect
|
|
* the absence of a nameserver without timing out.
|
|
* If we have sent queries to at least two servers,
|
|
* however, we don't want to remain connected,
|
|
* as we wish to receive answers from the first
|
|
* server to respond.
|
|
*/
|
|
if (_res.nscount == 1 || (try == 0 && ns == 0)) {
|
|
/*
|
|
* Connect only if we are sure we won't
|
|
* receive a response from another server.
|
|
*/
|
|
if (!connected) {
|
|
if (connect(s, (struct sockaddr *)nsap,
|
|
sizeof *nsap
|
|
) < 0) {
|
|
Aerror(stderr,
|
|
"connect(dg)",
|
|
errno, *nsap);
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
connected = 1;
|
|
}
|
|
if (send(s, (char*)buf, buflen, 0) != buflen) {
|
|
Perror(stderr, "send", errno);
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
} else {
|
|
/*
|
|
* Disconnect if we want to listen
|
|
* for responses from more than one server.
|
|
*/
|
|
if (connected) {
|
|
#ifdef CAN_RECONNECT
|
|
struct sockaddr_in no_addr;
|
|
|
|
no_addr.sin_family = AF_INET;
|
|
no_addr.sin_addr.s_addr = INADDR_ANY;
|
|
no_addr.sin_port = 0;
|
|
(void) connect(s,
|
|
(struct sockaddr *)
|
|
&no_addr,
|
|
sizeof no_addr);
|
|
#else
|
|
int s1 = socket(PF_INET, SOCK_DGRAM,0);
|
|
if (s1 < 0)
|
|
goto bad_dg_sock;
|
|
(void)dup2(s1, s);
|
|
(void)_close(s1);
|
|
Dprint(_res.options & RES_DEBUG,
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|
(stdout, ";; new DG socket\n"))
|
|
#endif /* CAN_RECONNECT */
|
|
connected = 0;
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|
errno = 0;
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|
}
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|
#endif /* !CANNOT_CONNECT_DGRAM */
|
|
if (sendto(s, (char*)buf, buflen, 0,
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|
(struct sockaddr *)nsap,
|
|
sizeof *nsap)
|
|
!= buflen) {
|
|
Aerror(stderr, "sendto", errno, *nsap);
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|
badns |= (1 << ns);
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|
res_close();
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|
goto next_ns;
|
|
}
|
|
#ifndef CANNOT_CONNECT_DGRAM
|
|
}
|
|
#endif /* !CANNOT_CONNECT_DGRAM */
|
|
|
|
/*
|
|
* Wait for reply
|
|
*/
|
|
#ifndef NOPOLL
|
|
othersyscall:
|
|
if (use_poll) {
|
|
struct timeval itv;
|
|
|
|
msec = (_res.retrans << try) * 1000;
|
|
if (try > 0)
|
|
msec /= _res.nscount;
|
|
if (msec <= 0)
|
|
msec = 1000;
|
|
gettimeofday(&timeout, NULL);
|
|
itv.tv_sec = msec / 1000;
|
|
itv.tv_usec = (msec % 1000) * 1000;
|
|
timeradd(&timeout, &itv, &timeout);
|
|
} else {
|
|
#endif
|
|
timeout.tv_sec = (_res.retrans << try);
|
|
if (try > 0)
|
|
timeout.tv_sec /= _res.nscount;
|
|
if ((long) timeout.tv_sec <= 0)
|
|
timeout.tv_sec = 1;
|
|
timeout.tv_usec = 0;
|
|
#ifndef NOPOLL
|
|
}
|
|
#endif
|
|
wait:
|
|
if (s < 0) {
|
|
Perror(stderr, "s out-of-bounds", EMFILE);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
#ifndef NOPOLL
|
|
if (use_poll) {
|
|
struct sigaction sa, osa;
|
|
int sigsys_installed = 0;
|
|
|
|
pfd.fd = s;
|
|
pfd.events = POLLIN;
|
|
if (use_poll == 1) {
|
|
sigemptyset(&sa.sa_mask);
|
|
sa.sa_flags = 0;
|
|
sa.sa_handler = SIG_IGN;
|
|
if (sigaction(SIGSYS, &sa, &osa) >= 0)
|
|
sigsys_installed = 1;
|
|
}
|
|
n = poll(&pfd, 1, msec);
|
|
if (sigsys_installed == 1) {
|
|
int oerrno = errno;
|
|
sigaction(SIGSYS, &osa, NULL);
|
|
errno = oerrno;
|
|
}
|
|
/* XXX why does nosys() return EINVAL? */
|
|
if (n < 0 && (errno == ENOSYS ||
|
|
errno == EINVAL)) {
|
|
use_poll = 0;
|
|
goto othersyscall;
|
|
} else if (use_poll == 1)
|
|
use_poll = 2;
|
|
if (n < 0) {
|
|
if (errno == EINTR) {
|
|
struct timeval ctv;
|
|
|
|
gettimeofday(&ctv, NULL);
|
|
if (timercmp(&ctv, &timeout, <)) {
|
|
timersub(&timeout,
|
|
&ctv, &ctv);
|
|
msec = ctv.tv_sec * 1000;
|
|
msec += ctv.tv_usec / 1000;
|
|
goto wait;
|
|
}
|
|
} else {
|
|
Perror(stderr, "poll", errno);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
}
|
|
} else {
|
|
#endif
|
|
dsmasklen = howmany(s + 1, NFDBITS) *
|
|
sizeof(fd_mask);
|
|
if (dsmasklen > sizeof(fd_set)) {
|
|
dsmaskp = (fd_set *)malloc(dsmasklen);
|
|
if (dsmaskp == NULL) {
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
} else
|
|
dsmaskp = &dsmask;
|
|
/* only zero what we need */
|
|
bzero((char *)dsmaskp, dsmasklen);
|
|
FD_SET(s, dsmaskp);
|
|
n = select(s + 1, dsmaskp, (fd_set *)NULL,
|
|
(fd_set *)NULL, &timeout);
|
|
if (dsmaskp != &dsmask)
|
|
free(dsmaskp);
|
|
if (n < 0) {
|
|
if (errno == EINTR)
|
|
goto wait;
|
|
Perror(stderr, "select", errno);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
#ifndef NOPOLL
|
|
}
|
|
#endif
|
|
|
|
if (n == 0) {
|
|
/*
|
|
* timeout
|
|
*/
|
|
Dprint(_res.options & RES_DEBUG,
|
|
(stdout, ";; timeout\n"));
|
|
gotsomewhere = 1;
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
errno = 0;
|
|
fromlen = sizeof(struct sockaddr_in);
|
|
resplen = recvfrom(s, (char*)ans, anssiz, 0,
|
|
(struct sockaddr *)&from, &fromlen);
|
|
if (resplen <= 0) {
|
|
Perror(stderr, "recvfrom", errno);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
gotsomewhere = 1;
|
|
if (resplen < HFIXEDSZ) {
|
|
/*
|
|
* Undersized message.
|
|
*/
|
|
Dprint(_res.options & RES_DEBUG,
|
|
(stdout, ";; undersized: %d\n",
|
|
resplen));
|
|
terrno = EMSGSIZE;
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
if (hp->id != anhp->id) {
|
|
/*
|
|
* response from old query, ignore it.
|
|
* XXX - potential security hazard could
|
|
* be detected here.
|
|
*/
|
|
DprintQ((_res.options & RES_DEBUG) ||
|
|
(_res.pfcode & RES_PRF_REPLY),
|
|
(stdout, ";; old answer:\n"),
|
|
ans, (resplen>anssiz)?anssiz:resplen);
|
|
goto wait;
|
|
}
|
|
#ifdef CHECK_SRVR_ADDR
|
|
if (!(_res.options & RES_INSECURE1) &&
|
|
!res_isourserver(&from)) {
|
|
/*
|
|
* response from wrong server? ignore it.
|
|
* XXX - potential security hazard could
|
|
* be detected here.
|
|
*/
|
|
DprintQ((_res.options & RES_DEBUG) ||
|
|
(_res.pfcode & RES_PRF_REPLY),
|
|
(stdout, ";; not our server:\n"),
|
|
ans, (resplen>anssiz)?anssiz:resplen);
|
|
goto wait;
|
|
}
|
|
#endif
|
|
if (!(_res.options & RES_INSECURE2) &&
|
|
!res_queriesmatch(buf, buf + buflen,
|
|
ans, ans + anssiz)) {
|
|
/*
|
|
* response contains wrong query? ignore it.
|
|
* XXX - potential security hazard could
|
|
* be detected here.
|
|
*/
|
|
DprintQ((_res.options & RES_DEBUG) ||
|
|
(_res.pfcode & RES_PRF_REPLY),
|
|
(stdout, ";; wrong query name:\n"),
|
|
ans, (resplen>anssiz)?anssiz:resplen);
|
|
goto wait;
|
|
}
|
|
if (anhp->rcode == SERVFAIL ||
|
|
anhp->rcode == NOTIMP ||
|
|
anhp->rcode == REFUSED) {
|
|
DprintQ(_res.options & RES_DEBUG,
|
|
(stdout, "server rejected query:\n"),
|
|
ans, (resplen>anssiz)?anssiz:resplen);
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
/* don't retry if called from dig */
|
|
if (!_res.pfcode)
|
|
goto next_ns;
|
|
}
|
|
if (!(_res.options & RES_IGNTC) && anhp->tc) {
|
|
/*
|
|
* get rest of answer;
|
|
* use TCP with same server.
|
|
*/
|
|
Dprint(_res.options & RES_DEBUG,
|
|
(stdout, ";; truncated answer\n"));
|
|
v_circuit = 1;
|
|
res_close();
|
|
goto same_ns;
|
|
}
|
|
} /*if vc/dg*/
|
|
Dprint((_res.options & RES_DEBUG) ||
|
|
((_res.pfcode & RES_PRF_REPLY) &&
|
|
(_res.pfcode & RES_PRF_HEAD1)),
|
|
(stdout, ";; got answer:\n"));
|
|
DprintQ((_res.options & RES_DEBUG) ||
|
|
(_res.pfcode & RES_PRF_REPLY),
|
|
(stdout, ""),
|
|
ans, (resplen>anssiz)?anssiz:resplen);
|
|
/*
|
|
* If using virtual circuits, we assume that the first server
|
|
* is preferred over the rest (i.e. it is on the local
|
|
* machine) and only keep that one open.
|
|
* If we have temporarily opened a virtual circuit,
|
|
* or if we haven't been asked to keep a socket open,
|
|
* close the socket.
|
|
*/
|
|
if ((v_circuit && (!(_res.options & RES_USEVC) || ns != 0)) ||
|
|
!(_res.options & RES_STAYOPEN)) {
|
|
res_close();
|
|
}
|
|
if (Rhook) {
|
|
int done = 0, loops = 0;
|
|
|
|
do {
|
|
res_sendhookact act;
|
|
|
|
act = (*Rhook)(nsap, buf, buflen,
|
|
ans, anssiz, &resplen);
|
|
switch (act) {
|
|
case res_goahead:
|
|
case res_done:
|
|
done = 1;
|
|
break;
|
|
case res_nextns:
|
|
res_close();
|
|
goto next_ns;
|
|
case res_modified:
|
|
/* give the hook another try */
|
|
if (++loops < 42) /*doug adams*/
|
|
break;
|
|
/*FALLTHROUGH*/
|
|
case res_error:
|
|
/*FALLTHROUGH*/
|
|
default:
|
|
return (-1);
|
|
}
|
|
} while (!done);
|
|
|
|
}
|
|
return (resplen);
|
|
next_ns: ;
|
|
} /*foreach ns*/
|
|
} /*foreach retry*/
|
|
res_close();
|
|
if (!v_circuit) {
|
|
if (!gotsomewhere)
|
|
errno = ECONNREFUSED; /* no nameservers found */
|
|
else
|
|
errno = ETIMEDOUT; /* no answer obtained */
|
|
} else
|
|
errno = terrno;
|
|
return (-1);
|
|
}
|
|
|
|
/*
|
|
* This routine is for closing the socket if a virtual circuit is used and
|
|
* the program wants to close it. This provides support for endhostent()
|
|
* which expects to close the socket.
|
|
*
|
|
* This routine is not expected to be user visible.
|
|
*/
|
|
void
|
|
res_close()
|
|
{
|
|
if (s >= 0) {
|
|
(void)_close(s);
|
|
s = -1;
|
|
connected = 0;
|
|
vc = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Weak aliases for applications that use certain private entry points,
|
|
* and fail to include <resolv.h>.
|
|
*/
|
|
#undef res_close
|
|
__weak_reference(__res_close, _res_close);
|
|
#undef res_send
|
|
__weak_reference(__res_send, res_send);
|