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/*

 * Copyright (c) 1995

 *      Bill Paul <wpaul@ctr.columbia.edu>.  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 Bill Paul.

 * 4. Neither the name of the author nor the names of any co-contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY Bill Paul 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.

 *

 * ethernet address conversion and lookup routines

 *

 * Written by Bill Paul <wpaul@ctr.columbia.edu>

 * Center for Telecommunications Research

 * Columbia University, New York City

 *

 *      $Id: ether_addr.c,v 1.2 2001-09-27 12:01:53 chris Exp $

 */

#include <stdio.h>

#include <paths.h>

#include <sys/types.h>

#include <string.h>

#include <stdlib.h>

#include <sys/param.h>

#include <sys/socket.h>

#include <net/ethernet.h>

#ifdef YP

#include <rpc/rpc.h>

#include <rpcsvc/yp_prot.h>

#include <rpcsvc/ypclnt.h>

#endif

#ifndef _PATH_ETHERS

#define _PATH_ETHERS "/etc/ethers"

#endif

/*

 * Parse a string of text containing an ethernet address and hostname

 * and separate it into its component parts.

 */

int ether_line(l, e, hostname)

        char *l;

        struct ether_addr *e;

        char *hostname;

{

        int i, o[6];

        i = sscanf(l, "%x:%x:%x:%x:%x:%x %s", &o[0], &o[1], &o[2],

                                              &o[3], &o[4], &o[5],

                                              hostname);

        if (i != 7)

                return (i);

        for (i=0; i<6; i++)

                e->octet[i] = o[i];

        return (0);

}

/*

 * Convert an ASCII representation of an ethernet address to

 * binary form.

 */

struct ether_addr *ether_aton(a)

        char *a;

{

        int i;

        static struct ether_addr o;

        unsigned int o0, o1, o2, o3, o4, o5;

        i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o0, &o1, &o2, &o3, &o4, &o5);

        if (i != 6)

                return (NULL);

        o.octet[0]=o0;

        o.octet[1]=o1;

        o.octet[2]=o2;

        o.octet[3]=o3;

        o.octet[4]=o4;

        o.octet[5]=o5;

        return ((struct ether_addr *)&o);

}

/*

 * Convert a binary representation of an ethernet address to

 * an ASCII string.

 */

char *ether_ntoa(n)

        struct ether_addr *n;

{

        int i;

        static char a[18];

        i = sprintf(a,"%x:%x:%x:%x:%x:%x",n->octet[0],n->octet[1],n->octet[2],

                                          n->octet[3],n->octet[4],n->octet[5]);

        if (i < 11)

                return (NULL);

        return ((char *)&a);

}

/*

 * Map an ethernet address to a hostname. Use either /etc/ethers or

 * NIS/YP.

 */

int ether_ntohost(hostname, e)

        char *hostname;

        struct ether_addr *e;

{

        FILE *fp;

        char buf[BUFSIZ + 2];

        struct ether_addr local_ether;

        char local_host[MAXHOSTNAMELEN];

#ifdef YP

        char *result;

        int resultlen;

        char *ether_a;

        char *yp_domain;

#endif

        if ((fp = fopen(_PATH_ETHERS, "r")) == NULL)

                return (1);

        while (fgets(buf,BUFSIZ,fp)) {

                if (buf[0] == '#')

                        continue;

#ifdef YP

                if (buf[0] == '+') {

                        if (yp_get_default_domain(&yp_domain))

                                continue;

                        ether_a = ether_ntoa(e);

                        if (yp_match(yp_domain, "ethers.byaddr", ether_a,

                                strlen(ether_a), &result, &resultlen)) {

                                continue;

                        }

                        strncpy(buf, result, resultlen);

                        buf[resultlen] = '\0';

                        free(result);

                }

#endif

                if (!ether_line(buf, &local_ether, local_host)) {

                        if (!bcmp((char *)&local_ether.octet[0],

                                (char *)&e->octet[0], 6)) {

                        /* We have a match */

                                strcpy(hostname, local_host);

                                fclose(fp);

                                return(0);

                        }

                }

        }

        fclose(fp);

        return (1);

}

/*

 * Map a hostname to an ethernet address using /etc/ethers or

 * NIS/YP.

 */

int ether_hostton(hostname, e)

        char *hostname;

        struct ether_addr *e;

{

        FILE *fp;

        char buf[BUFSIZ + 2];

        struct ether_addr local_ether;

        char local_host[MAXHOSTNAMELEN];

#ifdef YP

        char *result;

        int resultlen;

        char *yp_domain;

#endif

        if ((fp = fopen(_PATH_ETHERS, "r")) == NULL)

                return (1);

        while (fgets(buf,BUFSIZ,fp)) {

                if (buf[0] == '#')

                        continue;

#ifdef YP

                if (buf[0] == '+') {

                        if (yp_get_default_domain(&yp_domain))

                                continue;

                        if (yp_match(yp_domain, "ethers.byname", hostname,

                                strlen(hostname), &result, &resultlen)) {

                                continue;

                        }

                        strncpy(buf, result, resultlen);

                        buf[resultlen] = '\0';

                        free(result);

                }

#endif

                if (!ether_line(buf, &local_ether, local_host)) {

                        if (!strcmp(hostname, local_host)) {

                                /* We have a match */

                                bcopy((char *)&local_ether.octet[0],

                                        (char *)&e->octet[0], 6);

                                fclose(fp);

                                return(0);

                        }

                }

        }

        fclose(fp);

        return (1);

}