/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 1995 Bill Paul <wpaul@ctr.columbia.edu>.
 * Copyright (c) 2007 Robert N. M. Watson
 * 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
 */

#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

#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#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(const 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) {
                for (i = 0; i < 6; i++)
                        e->octet[i] = o[i];
                return (0);
        } else {
                return (-1);
        }
}

/*
 * Convert an ASCII representation of an ethernet address to binary form.
 */
struct ether_addr *
ether_aton_r(const char *a, struct ether_addr *e)
{
        int i;
        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);
        e->octet[0]=o0;
        e->octet[1]=o1;
        e->octet[2]=o2;
        e->octet[3]=o3;
        e->octet[4]=o4;
        e->octet[5]=o5;
        return (e);
}

struct ether_addr *
ether_aton(const char *a)
{
        static struct ether_addr e;

        return (ether_aton_r(a, &e));
}

/*
 * Convert a binary representation of an ethernet address to an ASCII string.
 */
char *
ether_ntoa_r(const struct ether_addr *n, char *a)
{
        int i;

        i = sprintf(a, "%02x:%02x:%02x:%02x:%02x:%02x", n->octet[0],
            n->octet[1], n->octet[2], n->octet[3], n->octet[4], n->octet[5]);
        if (i < 17)
                return (NULL);
        return (a);
}

char *
ether_ntoa(const struct ether_addr *n)
{
        static char a[18];

        return (ether_ntoa_r(n, a));
}

/*
 * Map an ethernet address to a hostname. Use either /etc/ethers or NIS/YP.
 */
int
ether_ntohost(char *hostname, const 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, "re")) == 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(const 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, "re")) == 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);
}