/** @file
  Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials are licensed and made available under
  the terms and conditions of the BSD License that accompanies this distribution.
  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php.

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

 * Portions copyright (c) 1999, 2000
 * Intel Corporation.
 * 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 Intel Corporation and
 *    its contributors.
 * 
 * 4. Neither the name of Intel Corporation or its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION 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 INTEL CORPORATION 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.
 * 
 * Copyright (c) 1996 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM 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.
**/

#include <sys/types.h>

#include <netinet/in.h>
#include <arpa/nameser.h>

#include <errno.h>
#include <resolv.h>
#include <string.h>

/* These need to be in the same order as the nres.h:ns_flag enum. */
struct _ns_flagdata _ns_flagdata[16] = {
	{ 0x8000, 15 },		/* qr. */
	{ 0x7800, 11 },		/* opcode. */
	{ 0x0400, 10 },		/* aa. */
	{ 0x0200, 9 },		/* tc. */
	{ 0x0100, 8 },		/* rd. */
	{ 0x0080, 7 },		/* ra. */
	{ 0x0040, 6 },		/* z. */
	{ 0x0020, 5 },		/* ad. */
	{ 0x0010, 4 },		/* cd. */
	{ 0x000f, 0 },		/* rcode. */
	{ 0x0000, 0 },		/* expansion (1/6). */
	{ 0x0000, 0 },		/* expansion (2/6). */
	{ 0x0000, 0 },		/* expansion (3/6). */
	{ 0x0000, 0 },		/* expansion (4/6). */
	{ 0x0000, 0 },		/* expansion (5/6). */
	{ 0x0000, 0 },		/* expansion (6/6). */
};

static int
skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
	const u_char *optr = ptr;

	for ((void)NULL; count > 0; count--) {
		int b, rdlength;

		b = dn_skipname(ptr, eom);
		if (b < 0)
			goto emsgsize;
		ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
		if (section != ns_s_qd) {
			if (ptr + NS_INT32SZ > eom)
				goto emsgsize;
			ptr += NS_INT32SZ/*TTL*/;
			if (ptr + NS_INT16SZ > eom)
				goto emsgsize;
			NS_GET16(rdlength, ptr);
			ptr += rdlength/*RData*/;
		}
	}
	if (ptr > eom)
		goto emsgsize;
	return ((int)(ptr - optr));
 emsgsize:
	errno = EMSGSIZE;
	return (-1);
}

int
ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
	const u_char *eom = msg + msglen;
	int i;

	memset(handle, 0x5e, sizeof *handle);
	handle->_msg = msg;
	handle->_eom = eom;
	if (msg + NS_INT16SZ > eom)
		goto emsgsize;
	NS_GET16(handle->_id, msg);
	if (msg + NS_INT16SZ > eom)
		goto emsgsize;
	NS_GET16(handle->_flags, msg);
	for (i = 0; i < ns_s_max; i++) {
		if (msg + NS_INT16SZ > eom)
			goto emsgsize;
		NS_GET16(handle->_counts[i], msg);
	}
	for (i = 0; i < ns_s_max; i++)
		if (handle->_counts[i] == 0)
			handle->_sections[i] = NULL;
		else {
			int b = skiprr(msg, eom, (ns_sect)i,
				       handle->_counts[i]);

			if (b < 0)
				return (-1);
			handle->_sections[i] = msg;
			msg += b;
		}
	if (msg != eom)
		goto emsgsize;
	handle->_sect = ns_s_max;
	handle->_rrnum = -1;
	handle->_msg_ptr = NULL;
	return (0);
 emsgsize:
	errno = EMSGSIZE;
	return (-1);
}

int
ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
	int b;

	/* Make section right. */
	if ((unsigned int)section >= ns_s_max)
		goto enodev;
	if ((int)section != (int)handle->_sect) {
		handle->_sect = section;
		handle->_rrnum = 0;
		handle->_msg_ptr = handle->_sections[(int)section];
	}

	/* Make rrnum right. */
	if (rrnum == -1)
		rrnum = handle->_rrnum;
	if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
		goto enodev;
	if (rrnum < handle->_rrnum) {
		handle->_rrnum = 0;
		handle->_msg_ptr = handle->_sections[(int)section];
	}
	
	b = skiprr(handle->_msg, handle->_eom, section,
		   rrnum - handle->_rrnum);
	if (b < 0)
		return (-1);
	handle->_msg_ptr += b;
	handle->_rrnum = rrnum;

	/* Do the parse. */
	b = dn_expand(handle->_msg, handle->_eom,
		      handle->_msg_ptr, rr->name, NS_MAXDNAME);
	if (b < 0)
		return (-1);
	handle->_msg_ptr += b;
	if (handle->_msg_ptr + NS_INT16SZ > handle->_eom)
		goto emsgsize;
	NS_GET16(rr->type, handle->_msg_ptr);
	if (handle->_msg_ptr + NS_INT16SZ > handle->_eom)
		goto emsgsize;
	NS_GET16(rr->rr_class, handle->_msg_ptr);
	if (section == ns_s_qd) {
		rr->ttl = 0;
		rr->rdlength = 0;
		rr->rdata = NULL;
	} else {
		if (handle->_msg_ptr + NS_INT32SZ > handle->_eom)
			goto emsgsize;
		NS_GET32(rr->ttl, handle->_msg_ptr);
		if (handle->_msg_ptr + NS_INT16SZ > handle->_eom)
			goto emsgsize;
		NS_GET16(rr->rdlength, handle->_msg_ptr);
		if (handle->_msg_ptr + rr->rdlength > handle->_eom)
			goto emsgsize;
		rr->rdata = handle->_msg_ptr;
		handle->_msg_ptr += rr->rdlength;
	}
	handle->_rrnum++;

	/* All done. */
	return (0);
 enodev:
	errno = ENODEV;
	return (-1);
 emsgsize:
	errno = EMSGSIZE;
	return (-1);
}