/*
 * Portions Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

/*
 * Copyright (c) 1983, 1990, 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.
 */

/*! \file lwinetaton.c
 */
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)inet_addr.c	8.1 (Berkeley) 6/17/93";
#endif /* LIBC_SCCS and not lint */

#include <config.h>

#include <ctype.h>
#include <inttypes.h>
#include <stddef.h>

#include <lwres/net.h>

#include "assert_p.h"

/*!
 * Check whether "cp" is a valid ascii representation
 * of an Internet address and convert to a binary address.
 * Returns 1 if the address is valid, 0 if not.
 * This replaces inet_addr, the return value from which
 * cannot distinguish between failure and a local broadcast address.
 */
int
lwres_net_aton(const char *cp, struct in_addr *addr) {
	uint32_t val;
	int base;
	ptrdiff_t n;
	unsigned char c;
	uint8_t parts[4];
	uint8_t *pp = parts;
	int digit;

	REQUIRE(cp != NULL);

	c = *cp;
	for (;;) {
		/*
		 * Collect number up to ``.''.
		 * Values are specified as for C:
		 * 0x=hex, 0=octal, isdigit=decimal.
		 */
		if (!isdigit(c & 0xff))
			return (0);
		val = 0;
		base = 10;
		digit = 0;
		if (c == '0') {
			c = *++cp;
			if (c == 'x' || c == 'X') {
				base = 16;
				c = *++cp;
			} else {
				base = 8;
				digit = 1;
			}
		}
		for (;;) {
			/*
			 * isascii() is valid for all integer values, and
			 * when it is true, c is known to be in scope
			 * for isdigit().  No cast necessary.  Similar
			 * comment applies for later ctype uses.
			 */
			if (isascii(c) && isdigit(c)) {
				if (base == 8 && (c == '8' || c == '9'))
					return (0);
				val = (val * base) + (c - '0');
				c = *++cp;
				digit = 1;
			} else if (base == 16 && isascii(c) && isxdigit(c)) {
				val = (val << 4) |
					(c + 10 - (islower(c) ? 'a' : 'A'));
				c = *++cp;
				digit = 1;
			} else
				break;
		}
		if (c == '.') {
			/*
			 * Internet format:
			 *	a.b.c.d
			 *	a.b.c	(with c treated as 16 bits)
			 *	a.b	(with b treated as 24 bits)
			 */
			if (pp >= parts + 3 || val > 0xffU)
				return (0);
			*pp++ = (uint8_t)val;
			c = *++cp;
		} else
			break;
	}
	/*
	 * Check for trailing characters.
	 */
	if (c != '\0' && (!isascii(c) || !isspace(c)))
		return (0);
	/*
	 * Did we get a valid digit?
	 */
	if (!digit)
		return (0);
	/*
	 * Concoct the address according to
	 * the number of parts specified.
	 */
	n = pp - parts + 1;
	switch (n) {
	case 1:				/* a -- 32 bits */
		break;

	case 2:				/* a.b -- 8.24 bits */
		if (val > 0xffffffU)
			return (0);
#define ulshift(x, n) ((unsigned int)(x) << (n))
		val |= ulshift(parts[0], 24);
		break;

	case 3:				/* a.b.c -- 8.8.16 bits */
		if (val > 0xffffU)
			return (0);
		val |= ulshift(parts[0], 24) | ulshift(parts[1], 16);
		break;

	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
		if (val > 0xffU)
			return (0);
		val |= ulshift(parts[0], 24) | ulshift(parts[1], 16) |
			ulshift(parts[2], 8);
		break;
	}
	if (addr != NULL)
		addr->s_addr = htonl(val);

	return (1);
}