/*
 * ++Copyright++ 1985, 1993
 * -
 * Copyright (c) 1985, 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. 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--
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)res_comp.c	8.1 (Berkeley) 6/4/93";
static char rcsid[] = "$Id: res_comp.c,v 1.4 2003/02/18 17:29:24 majka Exp $";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <netinet/in.h>

#include <stdio.h>
#include <ctype.h>

#include <arpa/nameser_compat.h>
#include <nameser.h>

/*
 * Expand compressed domain name 'comp_dn' to full domain name.
 * 'msg' is a pointer to the begining of the message,
 * 'eomorig' points to the first location after the message,
 * 'exp_dn' is a pointer to a buffer of size 'length' for the result.
 * Return size of compressed name or -1 if there was an error.
 */
int
dn_expand(const u_char *msg, const u_char *eomorig, const u_char *comp_dn, char *exp_dn, int length)
{
	register const u_char *cp;
	register char *dn;
	register int n, c;
	char *eom;
	int len = -1, checked = 0;

	dn = exp_dn;
	cp = comp_dn;
	eom = exp_dn + length;
	/*
	 * fetch next label in domain name
	 */
	while ((n = *cp++)) {
		/*
		 * Check for indirection
		 */
		switch (n & INDIR_MASK) {
		case 0:
			if (dn != exp_dn) {
				if (dn >= eom)
					return (-1);
				*dn++ = '.';
			}
			if (dn+n >= eom)
				return (-1);
			checked += n + 1;
			while (--n >= 0) {
				if ((c = *cp++) == '.') {
					if (dn + n + 2 >= eom)
						return (-1);
					*dn++ = '\\';
				}
				*dn++ = c;
				if (cp >= eomorig)	/* out of range */
					return (-1);
			}
			break;

		case INDIR_MASK:
			if (len < 0)
				len = cp - comp_dn + 1;
			cp = msg + (((n & 0x3f) << 8) | (*cp & 0xff));
			if (cp < msg || cp >= eomorig)	/* out of range */
				return (-1);
			checked += 2;
			/*
			 * Check for loops in the compressed name;
			 * if we've looked at the whole message,
			 * there must be a loop.
			 */
			if (checked >= eomorig - msg)
				return (-1);
			break;

		default:
			return (-1);			/* flag error */
		}
	}
	*dn = '\0';
	for (dn = exp_dn; (c = *dn) != '\0'; dn++)
		if (isascii(c) && isspace(c))
			return (-1);
	if (len < 0)
		len = cp - comp_dn;
	return (len);
}

/*
 * Skip over a compressed domain name. Return the size or -1.
 */
int
__dn_skipname(const u_char *comp_dn, const u_char *eom)
{
	register const u_char *cp;
	register int n;

	cp = comp_dn;
	while (cp < eom && (n = *cp++)) {
		/*
		 * check for indirection
		 */
		switch (n & INDIR_MASK) {
		case 0:			/* normal case, n == len */
			cp += n;
			continue;
		case INDIR_MASK:	/* indirection */
			cp++;
			break;
		default:		/* illegal type */
			return (-1);
		}
		break;
	}
	if (cp > eom)
		return (-1);
	return (cp - comp_dn);
}

/*
 * Routines to insert/extract short/long's.
 */

u_int16_t
_getshort(const u_char *msgp)
{
	u_int16_t u;
	GETSHORT(u, msgp);
	return u;
}

u_int32_t
_getlong(const u_char *msgp)
{
	u_int32_t u;
	GETLONG(u, msgp);
	return u;
}