ether_addr.c   [plain text]

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
 * Reserved.  This file contains Original Code and/or Modifications of
 * Original Code as defined in and that are subject to the Apple Public
 * Source License Version 1.1 (the "License").  You may not use this file
 * except in compliance with the License.  Please obtain a copy of the
 * License at http://www.apple.com/publicsource and read it before using
 * this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
#if !defined(lint) && defined(SCCSIDS)
static  char sccsid[] = "@(#)ether_addr.c	1.2 88/05/10 4.0NFSSRC; from 1.9 88/02/08 Copyr 1985 Sun Micro";
#endif

/*
 * Copyright (c) 1985 by Sun Microsystems, Inc.
 *
 * All routines necessary to deal with the file /etc/ethers.  The file
 * contains mappings from 48 bit ethernet addresses to their corresponding
 * hosts name.  The addresses have an ascii representation of the form
 * "x:x:x:x:x:x" where x is a hex number between 0x00 and 0xff;  the
 * bytes are always in network order.
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>

static const char ethers[] = "/etc/ethers";

/*
 * Parses a line from /etc/ethers into its components.  The line has the form
 * 8:0:20:1:17:c8	krypton
 * where the first part is a 48 bit ethernet addrerss and the second is
 * the corresponding hosts name.
 * Returns zero if successful, non-zero otherwise.
 */
int ether_line(s, e, hostname)
	const char *s;		/* the string to be parsed */
	struct ether_addr *e;	/* ethernet address struct to be filled in */
	char *hostname;		/* hosts name to be set */
{
	register int i;
	unsigned int t[6];
	
	i = sscanf(s, " %x:%x:%x:%x:%x:%x %s",
	    &t[0], &t[1], &t[2], &t[3], &t[4], &t[5], hostname);
	if (i != 7) {
		return (7 - i);
	}
	for (i = 0; i < 6; i++)
		e->ether_addr_octet[i] = t[i];
	return (0);
}

/*
 * Converts a 48 bit ethernet number to its string representation.
 */
#define EI(i)	(unsigned int)(e->ether_addr_octet[(i)])
char *
ether_ntoa(e)
	const struct ether_addr *e;
{
	static char *s;

	if (s == 0) {
		s = (char *)malloc(18);
		if (s == 0)
			return (0);
	}
	s[0] = 0;
	sprintf(s, "%x:%x:%x:%x:%x:%x",
	    EI(0), EI(1), EI(2), EI(3), EI(4), EI(5));
	return (s);
}

/*
 * Converts a ethernet address representation back into its 48 bits.
 */
struct ether_addr *
ether_aton(s)
	const char *s;
{
	static struct ether_addr *ep;
	register int i;
	unsigned int t[6];
	
	if (ep == 0) {
		ep = (struct ether_addr *)calloc(1, sizeof (struct ether_addr));
		if (ep == 0)
			return (0);
	}
	i = sscanf(s, " %x:%x:%x:%x:%x:%x",
	    &t[0], &t[1], &t[2], &t[3], &t[4], &t[5]);
	if (i != 6)
	    return ((struct ether_addr *)NULL);
	for (i = 0; i < 6; i++)
		ep->ether_addr_octet[i] = t[i];
	return (ep);
}

/*
 * Given a host's name, this routine returns its 48 bit ethernet address.
 * Returns zero if successful, non-zero otherwise.
 */
int _old_ether_hostton(host, e)
	const char *host;		/* function input */
	struct ether_addr *e;	/* function output */
{
	char currenthost[256];
	char buf[512];
	char *val = buf;
	register int reason;
	FILE *f;

	if ((f = fopen(ethers, "r")) == NULL)
	{
		return (-1);
	}

	reason = -1;
	while (fscanf(f, "%[^\n] ", val) == 1)
	{
		if ((ether_line(val, e, currenthost) == 0) &&
			(strcmp(currenthost, host) == 0))
		{
			reason = 0;
			break;
		}
	}

	fclose(f);
	return (reason);
}

/*
 * Given a 48 bit ethernet address, this routine return its host name.
 * Returns zero if successful, non-zero otherwise.
 */
int _old_ether_ntohost(host, e)
	char *host;		/* function output */
	const struct ether_addr *e;	/* function input */
{
	struct ether_addr currente;
	char buf[512];
	char *val = buf;
	register int reason;
	FILE *f;
	
	if ((f = fopen(ethers, "r")) == NULL)
	{
		return (-1);
	}

	reason = -1;
	while (fscanf(f, "%[^\n] ", val) == 1)
	{
		if ((ether_line(val, &currente, host) == 0) &&
			(bcmp(e, &currente, sizeof(currente)) == 0))
		{
			reason = 0;
			break;
		}
	}

	fclose(f);
	return (reason);
}