inet_a~1.c

操作系统源代码

/*
 * Copyright (c) 1983, 1990 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that: (1) source distributions retain this entire copyright notice and
 * comment, and (2) distributions including binaries display the following
 * acknowledgement:  ``This product includes software developed by the
 * University of California, Berkeley and its contributors'' in the
 * documentation or other materials provided with the distribution and in
 * all advertising materials mentioning features or use of this software.
 * 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)inet_addr.c	5.8 (Berkeley) 6/23/90";
#endif /* LIBC_SCCS and not lint */

#if _MINIX
#include <sys/types.h>
#include <ctype.h>
#include <errno.h>

#include <net/hton.h>
#include <net/gen/in.h>
#include <net/gen/inet.h>
#endif

#ifdef __STDC__
#define _CONST	const
#else
#define _CONST
#endif

/*
 * Ascii internet address interpretation routine.
 * The value returned is in network order.
 */
ipaddr_t
inet_addr(cp)
	register _CONST char *cp;
{
	ipaddr_t val;

	if (inet_aton(cp, &val))
		return (val);
	errno= EINVAL;
	return (ipaddr_t)-1;
}

/* 
 * 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
inet_aton(cp, addr)
	register _CONST char *cp;
	ipaddr_t *addr;
{
	register u32_t val, base, n;
	register char c;
	u32_t parts[4], *pp = parts;

	for (;;) {
		/*
		 * Collect number up to ``.''.
		 * Values are specified as for C:
		 * 0x=hex, 0=octal, other=decimal.
		 */
		val = 0; base = 10;
		if (*cp == '0') {
			if (*++cp == 'x' || *cp == 'X')
				base = 16, cp++;
			else
				base = 8;
		}
		while ((c = *cp) != '\0') {
			if (isascii(c) && isdigit(c)) {
				val = (val * base) + (c - '0');
				cp++;
				continue;
			}
			if (base == 16 && isascii(c) && isxdigit(c)) {
				val = (val << 4) + 
					(c + 10 - (islower(c) ? 'a' : 'A'));
				cp++;
				continue;
			}
			break;
		}
		if (*cp == '.') {
			/*
			 * 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 > 0xff)
				return (0);
			*pp++ = val, cp++;
		} else
			break;
	}
	/*
	 * Check for trailing characters.
	 */
	if (*cp && (!isascii(*cp) || !isspace(*cp)))
		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 > 0xffffff)
			return (0);
		val |= parts[0] << 24;
		break;

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

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