416 lines
12 KiB
C
416 lines
12 KiB
C
/*
|
|
* Copyright (c) 1988, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
/*
|
|
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies, and that
|
|
* the name of Digital Equipment Corporation not be used in advertising or
|
|
* publicity pertaining to distribution of the document or software without
|
|
* specific, written prior permission.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
|
|
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
|
|
* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
|
|
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
|
|
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
|
|
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
|
|
* SOFTWARE.
|
|
*/
|
|
|
|
/*
|
|
* Portions Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
|
|
* Portions Copyright (c) 1996-2003 by Internet Software Consortium
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
|
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
|
|
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
*
|
|
* Internet Systems Consortium, Inc.
|
|
* 950 Charter Street
|
|
* Redwood City, CA 94063
|
|
* <info@isc.org>
|
|
* http://www.isc.org/
|
|
*/
|
|
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
|
static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
|
|
static const char rcsid[] = "$Id: res_query.c,v 1.4 2005/08/11 17:13:26 drochner Exp $";
|
|
#endif /* LIBC_SCCS and not lint */
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/param.h>
|
|
#include <netinet/in.h>
|
|
#include <arpa/inet.h>
|
|
#include <ctype.h>
|
|
#include <errno.h>
|
|
#include <netdb.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <sys/socket.h>
|
|
|
|
#include "minires/minires.h"
|
|
#include "arpa/nameser.h"
|
|
|
|
/* Options. Leave them on. */
|
|
#define DEBUG
|
|
|
|
#if PACKETSZ > 1024
|
|
#define MAXPACKET PACKETSZ
|
|
#else
|
|
#define MAXPACKET 1024
|
|
#endif
|
|
|
|
/*
|
|
* Formulate a normal query, send, and await answer.
|
|
* Returned answer is placed in supplied buffer "answer".
|
|
* Perform preliminary check of answer, returning success only
|
|
* if no error is indicated and the answer count is nonzero.
|
|
* Return the size of the response on success, -1 on error.
|
|
* Error number is left in H_ERRNO.
|
|
*
|
|
* Caller must parse answer and determine whether it answers the question.
|
|
*/
|
|
isc_result_t
|
|
res_nquery(res_state statp,
|
|
const char *name, /* domain name */
|
|
ns_class class, ns_type type, /* class and type of query */
|
|
double *answer, /* buffer to put answer */
|
|
unsigned anslen,
|
|
unsigned *ansret) /* size of answer buffer */
|
|
{
|
|
double buf[MAXPACKET / sizeof (double)];
|
|
HEADER *hp = (HEADER *) answer;
|
|
unsigned n;
|
|
isc_result_t rcode;
|
|
|
|
hp->rcode = NOERROR; /* default */
|
|
|
|
#ifdef DEBUG
|
|
if (statp->options & RES_DEBUG)
|
|
printf(";; res_query(%s, %d, %d)\n", name, class, type);
|
|
#endif
|
|
|
|
rcode = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
|
|
buf, sizeof(buf), &n);
|
|
if (rcode != ISC_R_SUCCESS) {
|
|
#ifdef DEBUG
|
|
if (statp->options & RES_DEBUG)
|
|
printf(";; res_query: mkquery failed\n");
|
|
#endif
|
|
RES_SET_H_ERRNO(statp, NO_RECOVERY);
|
|
return rcode;
|
|
}
|
|
rcode = res_nsend(statp, buf, n, answer, anslen, &n);
|
|
if (rcode != ISC_R_SUCCESS) {
|
|
#ifdef DEBUG
|
|
if (statp->options & RES_DEBUG)
|
|
printf(";; res_query: send error\n");
|
|
#endif
|
|
RES_SET_H_ERRNO(statp, TRY_AGAIN);
|
|
return rcode;
|
|
}
|
|
|
|
if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
|
|
#ifdef DEBUG
|
|
if (statp->options & RES_DEBUG)
|
|
printf(";; rcode = %d, ancount=%d\n", hp->rcode,
|
|
ntohs(hp->ancount));
|
|
#endif
|
|
switch (hp->rcode) {
|
|
case NXDOMAIN:
|
|
RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
|
|
break;
|
|
case SERVFAIL:
|
|
RES_SET_H_ERRNO(statp, TRY_AGAIN);
|
|
break;
|
|
case NOERROR:
|
|
RES_SET_H_ERRNO(statp, NO_DATA);
|
|
break;
|
|
case FORMERR:
|
|
case NOTIMP:
|
|
case REFUSED:
|
|
default:
|
|
RES_SET_H_ERRNO(statp, NO_RECOVERY);
|
|
break;
|
|
}
|
|
return ns_rcode_to_isc (hp -> rcode);
|
|
}
|
|
*ansret = n;
|
|
return ISC_R_SUCCESS;
|
|
}
|
|
|
|
#if 0
|
|
/*
|
|
* Formulate a normal query, send, and retrieve answer in supplied buffer.
|
|
* Return the size of the response on success, -1 on error.
|
|
* If enabled, implement search rules until answer or unrecoverable failure
|
|
* is detected. Error code, if any, is left in H_ERRNO.
|
|
*/
|
|
isc_result_t
|
|
res_nsearch(res_state statp,
|
|
const char *name, /* domain name */
|
|
ns_class class, ns_type type, /* class and type of query */
|
|
double *answer, /* buffer to put answer */
|
|
unsigned anslen,
|
|
unsigned *ansret) /* size of answer */
|
|
{
|
|
const char *cp, * const *domain;
|
|
HEADER *hp = (HEADER *) answer;
|
|
char tmp[NS_MAXDNAME];
|
|
u_int dots;
|
|
int trailing_dot, ret;
|
|
int got_nodata = 0, got_servfail = 0, root_on_list = 0;
|
|
isc_result_t rcode;
|
|
|
|
errno = 0;
|
|
RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */
|
|
|
|
dots = 0;
|
|
for (cp = name; *cp != '\0'; cp++)
|
|
dots += (*cp == '.');
|
|
trailing_dot = 0;
|
|
if (cp > name && *--cp == '.')
|
|
trailing_dot++;
|
|
|
|
/* If there aren't any dots, it could be a user-level alias. */
|
|
if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
|
|
return res_nquery(statp, cp, class, type,
|
|
answer, anslen, ansret);
|
|
|
|
/*
|
|
* If there are enough dots in the name, do no searching.
|
|
* (The threshold can be set with the "ndots" option.)
|
|
*/
|
|
if (dots >= statp->ndots || trailing_dot)
|
|
return res_nquerydomain(statp, name, NULL, class, type,
|
|
answer, anslen, ansret);
|
|
|
|
/*
|
|
* We do at least one level of search if
|
|
* - there is no dot and RES_DEFNAME is set, or
|
|
* - there is at least one dot, there is no trailing dot,
|
|
* and RES_DNSRCH is set.
|
|
*/
|
|
if ((!dots && (statp->options & RES_DEFNAMES) != 0) ||
|
|
(dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) {
|
|
int done = 0;
|
|
|
|
for (domain = (const char * const *)statp->dnsrch;
|
|
*domain && !done;
|
|
domain++) {
|
|
|
|
if (domain[0][0] == '\0' ||
|
|
(domain[0][0] == '.' && domain[0][1] == '\0'))
|
|
root_on_list++;
|
|
|
|
rcode = res_nquerydomain(statp, name, *domain,
|
|
class, type,
|
|
answer, anslen, &ret);
|
|
if (rcode == ISC_R_SUCCESS && ret > 0) {
|
|
*ansret = ret;
|
|
return rcode;
|
|
}
|
|
|
|
/*
|
|
* If no server present, give up.
|
|
* If name isn't found in this domain,
|
|
* keep trying higher domains in the search list
|
|
* (if that's enabled).
|
|
* On a NO_DATA error, keep trying, otherwise
|
|
* a wildcard entry of another type could keep us
|
|
* from finding this entry higher in the domain.
|
|
* If we get some other error (negative answer or
|
|
* server failure), then stop searching up,
|
|
* but try the input name below in case it's
|
|
* fully-qualified.
|
|
*/
|
|
if (errno == ECONNREFUSED) {
|
|
RES_SET_H_ERRNO(statp, TRY_AGAIN);
|
|
return ISC_R_CONNREFUSED;
|
|
}
|
|
|
|
switch (statp->res_h_errno) {
|
|
case NO_DATA:
|
|
got_nodata++;
|
|
/* FALLTHROUGH */
|
|
case HOST_NOT_FOUND:
|
|
/* keep trying */
|
|
break;
|
|
case TRY_AGAIN:
|
|
if (hp->rcode == SERVFAIL) {
|
|
/* try next search element, if any */
|
|
got_servfail++;
|
|
break;
|
|
}
|
|
/* FALLTHROUGH */
|
|
default:
|
|
/* anything else implies that we're done */
|
|
done++;
|
|
}
|
|
|
|
/* if we got here for some reason other than DNSRCH,
|
|
* we only wanted one iteration of the loop, so stop.
|
|
*/
|
|
if ((statp->options & RES_DNSRCH) == 0)
|
|
done++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the name has any dots at all, and "." is not on the search
|
|
* list, then try an as-is query now.
|
|
*/
|
|
if (statp->ndots) {
|
|
rcode = res_nquerydomain(statp, name, NULL, class, type,
|
|
answer, anslen, &ret);
|
|
if (rcode == ISC_R_SUCCESS && ret > 0) {
|
|
*ansret = ret;
|
|
return rcode;
|
|
}
|
|
}
|
|
|
|
/* if we got here, we didn't satisfy the search.
|
|
* if we did an initial full query, return that query's H_ERRNO
|
|
* (note that we wouldn't be here if that query had succeeded).
|
|
* else if we ever got a nodata, send that back as the reason.
|
|
* else send back meaningless H_ERRNO, that being the one from
|
|
* the last DNSRCH we did.
|
|
*/
|
|
if (got_nodata) {
|
|
RES_SET_H_ERRNO(statp, NO_DATA);
|
|
return ISC_R_NOTFOUND;
|
|
} else if (got_servfail) {
|
|
RES_SET_H_ERRNO(statp, TRY_AGAIN);
|
|
return ISC_R_TIMEDOUT;
|
|
}
|
|
return ISC_R_UNEXPECTED;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Perform a call on res_query on the concatenation of name and domain,
|
|
* removing a trailing dot from name if domain is NULL.
|
|
*/
|
|
isc_result_t
|
|
res_nquerydomain(res_state statp,
|
|
const char *name,
|
|
const char *domain,
|
|
ns_class class, ns_type type,
|
|
double *answer,
|
|
unsigned anslen,
|
|
unsigned *ansret)
|
|
{
|
|
char nbuf[MAXDNAME];
|
|
const char *longname = nbuf;
|
|
int n, d;
|
|
|
|
#ifdef DEBUG
|
|
if (statp->options & RES_DEBUG)
|
|
printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
|
|
name, domain?domain:"<Nil>", class, type);
|
|
#endif
|
|
if (domain == NULL) {
|
|
/*
|
|
* Check for trailing '.';
|
|
* copy without '.' if present.
|
|
*/
|
|
n = strlen(name);
|
|
if (n >= MAXDNAME) {
|
|
RES_SET_H_ERRNO(statp, NO_RECOVERY);
|
|
return ISC_R_NOSPACE;
|
|
}
|
|
n--;
|
|
if (n >= 0 && name[n] == '.') {
|
|
strncpy(nbuf, name, (unsigned)n);
|
|
nbuf[n] = '\0';
|
|
} else
|
|
longname = name;
|
|
} else {
|
|
n = strlen(name);
|
|
d = strlen(domain);
|
|
if (n + d + 1 >= MAXDNAME) {
|
|
RES_SET_H_ERRNO(statp, NO_RECOVERY);
|
|
return ISC_R_NOSPACE;
|
|
}
|
|
sprintf(nbuf, "%s.%s", name, domain);
|
|
}
|
|
return res_nquery(statp,
|
|
longname, class, type, answer, anslen, ansret);
|
|
}
|
|
|
|
const char *
|
|
res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
|
|
char *file, *cp1, *cp2;
|
|
char buf[BUFSIZ];
|
|
FILE *fp;
|
|
|
|
if (statp->options & RES_NOALIASES)
|
|
return (NULL);
|
|
file = getenv("HOSTALIASES");
|
|
if (file == NULL || (fp = fopen(file, "r")) == NULL)
|
|
return (NULL);
|
|
setbuf(fp, NULL);
|
|
buf[sizeof(buf) - 1] = '\0';
|
|
while (fgets(buf, sizeof(buf), fp)) {
|
|
for (cp1 = buf; *cp1 && !isspace((unsigned char)*cp1); ++cp1)
|
|
;
|
|
if (!*cp1)
|
|
break;
|
|
*cp1 = '\0';
|
|
if (ns_samename(buf, name) == 1) {
|
|
while (isspace((unsigned char)*++cp1))
|
|
;
|
|
if (!*cp1)
|
|
break;
|
|
for (cp2 = cp1 + 1; *cp2 && !isspace((unsigned char)*cp2); ++cp2)
|
|
;
|
|
*cp2 = '\0';
|
|
strncpy(dst, cp1, siz - 1);
|
|
dst[siz - 1] = '\0';
|
|
fclose(fp);
|
|
return (dst);
|
|
}
|
|
}
|
|
fclose(fp);
|
|
return (NULL);
|
|
}
|