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Diffstat (limited to 'usr.sbin/nslookup/skip.c')
| -rw-r--r-- | usr.sbin/nslookup/skip.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/usr.sbin/nslookup/skip.c b/usr.sbin/nslookup/skip.c new file mode 100644 index 0000000..4119951 --- /dev/null +++ b/usr.sbin/nslookup/skip.c @@ -0,0 +1,211 @@ +/* + * ++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 4.9.1.6 1994/06/01 21:10:16 vixie 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> +#include "../../conf/portability.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); +} |
