text: /*
   * 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
   *
   * $FreeBSD: src/lib/libc/net/ether_addr.c,v 1.17 2007/05/13 13:57:44 rwatson Exp $
   * $DragonFly: src/lib/libc/net/ether_addr.c,v 1.4 2005/11/13 02:04:47 swildner Exp $
   */
  
  #include <sys/types.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
  
  #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)
  		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_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, "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(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, "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);
  }
  