211 lines
6.2 KiB
C
211 lines
6.2 KiB
C
/*
|
||
* ++Copyright++ 1985, 1989
|
||
* -
|
||
* Copyright (c) 1985, 1989
|
||
* 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. All advertising materials mentioning features or use of this software
|
||
* must display the following acknowledgement:
|
||
* This product includes software developed by the University of
|
||
* California, Berkeley and its contributors.
|
||
* 4. 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.
|
||
* -
|
||
* --Copyright--
|
||
*/
|
||
|
||
#ifndef lint
|
||
static char sccsid[] = "@(#)skip.c 5.12 (Berkeley) 3/21/91";
|
||
static char rcsid[] = "$Id: skip.c,v 1.2 1997/04/13 10:52:20 mrg Exp $";
|
||
#endif /* not lint */
|
||
|
||
/*
|
||
*******************************************************************************
|
||
*
|
||
* skip.c --
|
||
*
|
||
* Routines to skip over portions of a query buffer.
|
||
*
|
||
* Note: this file has been submitted for inclusion in
|
||
* BIND resolver library. When this has been done, this file
|
||
* is no longer necessary (assuming there haven't been any
|
||
* changes).
|
||
*
|
||
* Adapted from 4.3BSD BIND res_debug.c
|
||
*
|
||
*******************************************************************************
|
||
*/
|
||
|
||
#include <sys/param.h>
|
||
#include <netinet/in.h>
|
||
#include <arpa/nameser.h>
|
||
#include <resolv.h>
|
||
#include <stdio.h>
|
||
|
||
char *res_skip_rr();
|
||
|
||
|
||
/*
|
||
*******************************************************************************
|
||
*
|
||
* res_skip --
|
||
*
|
||
* Skip the contents of a query.
|
||
*
|
||
* Interpretation of numFieldsToSkip argument:
|
||
* res_skip returns pointer to:
|
||
* 1 -> start of question records.
|
||
* 2 -> start of authoritative answer records.
|
||
* 3 -> start of additional records.
|
||
* 4 -> first byte after end of additional records.
|
||
*
|
||
* Results:
|
||
* (address) - success operation.
|
||
* NULL - a resource record had an incorrect format.
|
||
*
|
||
*******************************************************************************
|
||
*/
|
||
|
||
char *
|
||
res_skip(msg, numFieldsToSkip, eom)
|
||
char *msg;
|
||
int numFieldsToSkip;
|
||
char *eom;
|
||
{
|
||
register char *cp;
|
||
register HEADER *hp;
|
||
register int tmp;
|
||
register int n;
|
||
|
||
/*
|
||
* Skip the header fields.
|
||
*/
|
||
hp = (HEADER *)msg;
|
||
cp = msg + HFIXEDSZ;
|
||
|
||
/*
|
||
* skip question records.
|
||
*/
|
||
if (n = ntohs(hp->qdcount) ) {
|
||
while (--n >= 0 && cp < eom) {
|
||
tmp = dn_skipname((u_char *)cp, (u_char *)eom);
|
||
if (tmp == -1) return(NULL);
|
||
cp += tmp;
|
||
cp += INT16SZ; /* type */
|
||
cp += INT16SZ; /* class */
|
||
}
|
||
}
|
||
if (--numFieldsToSkip <= 0) return(cp);
|
||
|
||
/*
|
||
* skip authoritative answer records
|
||
*/
|
||
if (n = ntohs(hp->ancount)) {
|
||
while (--n >= 0 && cp < eom) {
|
||
cp = res_skip_rr(cp, eom);
|
||
if (cp == NULL) return(NULL);
|
||
}
|
||
}
|
||
if (--numFieldsToSkip == 0) return(cp);
|
||
|
||
/*
|
||
* skip name server records
|
||
*/
|
||
if (n = ntohs(hp->nscount)) {
|
||
while (--n >= 0 && cp < eom) {
|
||
cp = res_skip_rr(cp, eom);
|
||
if (cp == NULL) return(NULL);
|
||
}
|
||
}
|
||
if (--numFieldsToSkip == 0) return(cp);
|
||
|
||
/*
|
||
* skip additional records
|
||
*/
|
||
if (n = ntohs(hp->arcount)) {
|
||
while (--n >= 0 && cp < eom) {
|
||
cp = res_skip_rr(cp, eom);
|
||
if (cp == NULL) return(NULL);
|
||
}
|
||
}
|
||
|
||
return(cp);
|
||
}
|
||
|
||
|
||
/*
|
||
*******************************************************************************
|
||
*
|
||
* res_skip_rr --
|
||
*
|
||
* Skip over resource record fields.
|
||
*
|
||
* Results:
|
||
* (address) - success operation.
|
||
* NULL - a resource record had an incorrect format.
|
||
*******************************************************************************
|
||
*/
|
||
|
||
char *
|
||
res_skip_rr(cp, eom)
|
||
char *cp;
|
||
char *eom;
|
||
{
|
||
int tmp;
|
||
int dlen;
|
||
|
||
if ((tmp = dn_skipname((u_char *)cp, (u_char *)eom)) == -1)
|
||
return (NULL); /* compression error */
|
||
cp += tmp;
|
||
if ((cp + RRFIXEDSZ) > eom)
|
||
return (NULL);
|
||
cp += INT16SZ; /* type */
|
||
cp += INT16SZ; /* class */
|
||
cp += INT32SZ; /* ttl */
|
||
dlen = _getshort((u_char*)cp);
|
||
cp += INT16SZ; /* dlen */
|
||
cp += dlen;
|
||
if (cp > eom)
|
||
return (NULL);
|
||
return (cp);
|
||
}
|