5996ba4042
don't connect datagram socket if RES_INSECURE1. needed to implement IPv6 anycast UDP DNS queries as documented in <draft-ietf-ipngwg-dns-discovery-02.txt>. sync with kame.
974 lines
24 KiB
C
974 lines
24 KiB
C
/* $NetBSD: res_send.c,v 1.34 2001/09/13 11:05:02 itojun Exp $ */
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/*-
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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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* 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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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
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static char rcsid[] = "Id: res_send.c,v 8.13 1997/06/01 20:34:37 vixie Exp ";
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#else
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__RCSID("$NetBSD: res_send.c,v 1.34 2001/09/13 11:05:02 itojun Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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/* change this to "0"
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* if you talk to a lot
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* of multi-homed SunOS
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* ("broken") name servers.
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*/
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#define CHECK_SRVR_ADDR 1 /* XXX - should be in options.h */
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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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#if defined(_LIBC)
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#include "namespace.h"
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#endif
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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 <sys/poll.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 <assert.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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#if defined(BSD) && (BSD >= 199306)
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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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#else
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# include "../conf/portability.h"
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#endif
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#if defined(USE_OPTIONS_H)
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# include <../conf/options.h>
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#endif
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#ifdef __weak_alias
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__weak_alias(res_close,__res_close)
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__weak_alias(res_send,__res_send)
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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 ciruit? */
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static int af = 0; /* address family of socket */
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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 char abuf[NI_MAXHOST];
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static char pbuf[32];
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static void Aerror __P((FILE *, char *, int, struct sockaddr *));
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static void Perror __P((FILE *, char *, int));
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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 *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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if (getnameinfo(address, (size_t)address->sa_len, abuf,
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sizeof(abuf), pbuf, sizeof(pbuf),
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NI_NUMERICHOST|NI_NUMERICSERV|NI_WITHSCOPEID) != 0) {
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strcpy(abuf, "?");
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strcpy(pbuf, "?");
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}
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fprintf(file, "res_send: %s ([%s].%s): %s\n",
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string, abuf, pbuf, 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 res_send_setqhook __P((res_send_qhook));
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void res_send_setrhook __P((res_send_rhook));
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static res_send_qhook Qhook = NULL;
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static res_send_rhook Rhook = NULL;
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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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#ifdef INET6
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static struct sockaddr * get_nsaddr __P((size_t));
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/*
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* pick appropriate nsaddr_list for use. see res_init() for initialization.
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*/
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static struct sockaddr *
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get_nsaddr(n)
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size_t n;
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{
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if (!_res.nsaddr_list[n].sin_family) {
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/*
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* - _res_ext.nsaddr_list[n] holds an address that is larger
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* than struct sockaddr, and
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* - user code did not update _res.nsaddr_list[n].
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*/
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return (struct sockaddr *)(void *)&_res_ext.nsaddr_list[n];
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} else {
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/*
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* - user code updated _res.nsaddr_list[n], or
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* - _res.nsaddr_list[n] has the same content as
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* _res_ext.nsaddr_list[n].
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*/
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return (struct sockaddr *)(void *)&_res.nsaddr_list[n];
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}
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}
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#else
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#define get_nsaddr(n) ((struct sockaddr *)&_res.nsaddr_list[(n)])
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#endif
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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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#ifdef INET6
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const struct sockaddr_in6 *in6p = (const struct sockaddr_in6 *)
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(const void *)inp;
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const struct sockaddr_in6 *srv6;
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#endif
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const struct sockaddr_in *srv;
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int ns, ret;
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_DIAGASSERT(inp != NULL);
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ret = 0;
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switch (inp->sin_family) {
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#ifdef INET6
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case AF_INET6:
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for (ns = 0; ns < _res.nscount; ns++) {
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srv6 = (struct sockaddr_in6 *)(void *)
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get_nsaddr((size_t)ns);
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if (srv6->sin6_family == in6p->sin6_family &&
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srv6->sin6_port == in6p->sin6_port &&
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srv6->sin6_scope_id == in6p->sin6_scope_id &&
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(IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
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IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr,
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&in6p->sin6_addr))) {
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ret++;
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break;
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}
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}
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break;
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#endif
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case AF_INET:
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for (ns = 0; ns < _res.nscount; ns++) {
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srv = (struct sockaddr_in *)
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(void *)get_nsaddr((size_t)ns);
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if (srv->sin_family == inp->sin_family &&
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srv->sin_port == inp->sin_port &&
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(srv->sin_addr.s_addr == INADDR_ANY ||
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srv->sin_addr.s_addr == inp->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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break;
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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 + HFIXESDZ <= 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(((const HEADER*)(const void *)buf)->qdcount);
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_DIAGASSERT(name != NULL);
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_DIAGASSERT(buf != NULL);
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_DIAGASSERT(eom != NULL);
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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 = _getshort(cp); cp += INT16SZ;
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tclass = _getshort(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;
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int qdcount;
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|
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_DIAGASSERT(buf1 != NULL);
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_DIAGASSERT(eom1 != NULL);
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_DIAGASSERT(buf2 != NULL);
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_DIAGASSERT(eom2 != NULL);
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cp = buf1 + HFIXEDSZ;
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qdcount = ntohs(((const HEADER *)(const void *)buf1)->qdcount);
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if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
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return (-1);
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|
|
if (qdcount != ntohs(((const HEADER *)(const void *)buf2)->qdcount))
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return (0);
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while (qdcount-- > 0) {
|
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char tname[MAXDNAME+1];
|
|
int n, ttype, tclass;
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|
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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);
|
|
cp += n;
|
|
if (cp + 2 * INT16SZ > eom1)
|
|
return (-1);
|
|
ttype = _getshort(cp); cp += INT16SZ;
|
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tclass = _getshort(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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}
|
|
|
|
int
|
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res_send(buf, buflen, ans, anssiz)
|
|
const u_char *buf;
|
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int buflen;
|
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u_char *ans;
|
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int anssiz;
|
|
{
|
|
const HEADER *hp = (const HEADER *)(const void *)buf;
|
|
HEADER *anhp = (HEADER *)(void *)ans;
|
|
int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;
|
|
int n;
|
|
u_int badns; /* XXX NSMAX can't exceed #/bits in this var */
|
|
|
|
_DIAGASSERT(buf != NULL);
|
|
_DIAGASSERT(ans != NULL);
|
|
|
|
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
|
|
/* errno should have been set by res_init() in this case. */
|
|
return (-1);
|
|
}
|
|
if (anssiz < HFIXEDSZ) {
|
|
errno = EINVAL;
|
|
return (-1);
|
|
}
|
|
DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),
|
|
(stdout, ";; res_send()\n"), buf, buflen);
|
|
v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
|
|
gotsomewhere = 0;
|
|
connreset = 0;
|
|
terrno = ETIMEDOUT;
|
|
badns = 0;
|
|
|
|
/*
|
|
* Send request, RETRY times, or until successful
|
|
*/
|
|
for (try = 0; try < _res.retry; try++) {
|
|
for (ns = 0; ns < _res.nscount; ns++) {
|
|
struct sockaddr *nsap = get_nsaddr((size_t)ns);
|
|
socklen_t salen;
|
|
|
|
if (nsap->sa_len)
|
|
salen = nsap->sa_len;
|
|
#ifdef INET6
|
|
else if (nsap->sa_family == AF_INET6)
|
|
salen = sizeof(struct sockaddr_in6);
|
|
#endif
|
|
else if (nsap->sa_family == AF_INET)
|
|
salen = sizeof(struct sockaddr_in);
|
|
else
|
|
salen = 0; /* unknown, die on connect */
|
|
|
|
same_ns:
|
|
if (badns & (1 << ns)) {
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
|
|
if (Qhook) {
|
|
int done = 0, loops = 0;
|
|
|
|
do {
|
|
res_sendhookact act;
|
|
|
|
act = (*Qhook)((struct sockaddr_in **)&nsap,
|
|
&buf, &buflen,
|
|
ans, anssiz, &resplen);
|
|
switch (act) {
|
|
case res_goahead:
|
|
done = 1;
|
|
break;
|
|
case res_nextns:
|
|
res_close();
|
|
goto next_ns;
|
|
case res_done:
|
|
return (resplen);
|
|
case res_modified:
|
|
/* give the hook another try */
|
|
if (++loops < 42) /*doug adams*/
|
|
break;
|
|
/*FALLTHROUGH*/
|
|
case res_error:
|
|
/*FALLTHROUGH*/
|
|
default:
|
|
return (-1);
|
|
}
|
|
} while (!done);
|
|
}
|
|
|
|
Dprint((_res.options & RES_DEBUG) &&
|
|
getnameinfo(nsap, salen, abuf, sizeof(abuf),
|
|
NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID) == 0,
|
|
(stdout, ";; Querying server (# %d) address = %s\n",
|
|
ns + 1, abuf));
|
|
|
|
if (v_circuit) {
|
|
int truncated;
|
|
struct iovec iov[2];
|
|
u_short len;
|
|
u_char *cp;
|
|
|
|
/*
|
|
* Use virtual circuit;
|
|
* at most one attempt per server.
|
|
*/
|
|
try = _res.retry;
|
|
truncated = 0;
|
|
if ((s < 0) || (!vc) || (af != nsap->sa_family)) {
|
|
if (s >= 0)
|
|
res_close();
|
|
|
|
af = nsap->sa_family;
|
|
s = socket(af, SOCK_STREAM, 0);
|
|
if (s < 0) {
|
|
terrno = errno;
|
|
Perror(stderr, "socket(vc)", errno);
|
|
#if 0
|
|
return (-1);
|
|
#else
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
#endif
|
|
}
|
|
errno = 0;
|
|
if (connect(s, nsap, salen) < 0) {
|
|
terrno = errno;
|
|
Aerror(stderr, "connect/vc",
|
|
errno, nsap);
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
vc = 1;
|
|
}
|
|
/*
|
|
* Send length & message
|
|
*/
|
|
putshort((u_short)buflen, (u_char*)(void *)&len);
|
|
iov[0].iov_base = &len;
|
|
iov[0].iov_len = INT16SZ;
|
|
/* LINTED write does not affect base */
|
|
iov[1].iov_base = (void *)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, (size_t)len)) > 0) {
|
|
cp += n;
|
|
/* len is unsigned, no need to compare < 0 */
|
|
if ((len -= n) == 0)
|
|
break;
|
|
}
|
|
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 = _getshort(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, cp, (size_t)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, (size_t)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.
|
|
*/
|
|
time_t seconds, now, timeout, finish;
|
|
struct pollfd dsfd;
|
|
struct sockaddr_storage from;
|
|
socklen_t fromlen;
|
|
|
|
if ((s < 0) || vc || (af != nsap->sa_family)) {
|
|
if (vc)
|
|
res_close();
|
|
af = nsap->sa_family;
|
|
s = socket(af, SOCK_DGRAM, 0);
|
|
if (s < 0) {
|
|
#if !CAN_RECONNECT
|
|
bad_dg_sock:
|
|
#endif
|
|
terrno = errno;
|
|
Perror(stderr, "socket(dg)", errno);
|
|
#if 0
|
|
return (-1);
|
|
#else
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
#endif
|
|
}
|
|
connected = 0;
|
|
}
|
|
/*
|
|
* 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 poll 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.
|
|
*
|
|
* When the option "insecure1" is specified, we'd
|
|
* rather expect to see responses from an "unknown"
|
|
* address. In order to let the kernel accept such
|
|
* responses, do not connect the socket here.
|
|
* XXX: or do we need an explicit option to disable
|
|
* connecting?
|
|
*/
|
|
if (!(_res.options & RES_INSECURE1) &&
|
|
(_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, nsap, salen) < 0) {
|
|
Aerror(stderr,
|
|
"connect(dg)",
|
|
errno, nsap);
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
connected = 1;
|
|
}
|
|
if (send(s, buf, (size_t)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) {
|
|
#if CAN_RECONNECT
|
|
#ifdef INET6
|
|
/* XXX: any errornous address */
|
|
#endif /* INET6 */
|
|
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 *)(void *)&no_addr,
|
|
sizeof(no_addr));
|
|
#else
|
|
int s1 = socket(af, SOCK_DGRAM,0);
|
|
if (s1 < 0)
|
|
goto bad_dg_sock;
|
|
(void) dup2(s1, s);
|
|
(void) close(s1);
|
|
Dprint(_res.options & RES_DEBUG,
|
|
(stdout, ";; new DG socket\n"))
|
|
#endif
|
|
connected = 0;
|
|
errno = 0;
|
|
}
|
|
if (sendto(s, buf, (size_t)buflen, 0,
|
|
nsap, salen) != buflen) {
|
|
Aerror(stderr, "sendto", errno, nsap);
|
|
badns |= (1 << ns);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Wait for reply
|
|
*/
|
|
seconds = (_res.retrans << try);
|
|
if (try > 0)
|
|
seconds /= _res.nscount;
|
|
if ((long) seconds <= 0)
|
|
seconds = 1;
|
|
now = time(NULL);
|
|
timeout = seconds;
|
|
finish = now + timeout;
|
|
dsfd.fd = s;
|
|
dsfd.events = POLLIN;
|
|
wait:
|
|
n = poll(&dsfd, 1, (int)(timeout * 1000));
|
|
if (n < 0) {
|
|
if (errno == EINTR) {
|
|
now = time(NULL);
|
|
if (finish > now) {
|
|
timeout = finish - now;
|
|
goto wait;
|
|
}
|
|
}
|
|
Perror(stderr, "poll", errno);
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
if (n == 0) {
|
|
/*
|
|
* timeout
|
|
*/
|
|
Dprint(_res.options & RES_DEBUG,
|
|
(stdout, ";; timeout\n"));
|
|
gotsomewhere = 1;
|
|
res_close();
|
|
goto next_ns;
|
|
}
|
|
errno = 0;
|
|
fromlen = sizeof from;
|
|
resplen = recvfrom(s, ans, (size_t)anssiz, 0,
|
|
(struct sockaddr *)(void *)&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;
|
|
}
|
|
#if CHECK_SRVR_ADDR
|
|
if (!(_res.options & RES_INSECURE1) &&
|
|
!res_isourserver(
|
|
(struct sockaddr_in *)(void *)&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, "%s", ""),
|
|
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)(
|
|
(struct sockaddr_in *)(void *)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;
|
|
af = 0;
|
|
}
|
|
}
|
|
|
|
#ifdef ultrix
|
|
/* XXX: remove this cruft? - lukem */
|
|
/* ultrix 4.0 had some icky packaging in its libc.a. alias for it here.
|
|
* there is more gunk of this kind over in res_debug.c.
|
|
*/
|
|
|
|
void
|
|
_res_close()
|
|
{
|
|
res_close();
|
|
}
|
|
|
|
#undef res_send
|
|
int
|
|
res_send(buf, buflen, ans, anssiz)
|
|
const u_char *buf;
|
|
int buflen;
|
|
u_char *ans;
|
|
int anssiz;
|
|
{
|
|
return (__res_send(buf, buflen, ans, anssiz));
|
|
}
|
|
#endif /* Ultrix 4.0 hackery */
|