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/*
* rarpd support routines
*
* Written by Bill Paul <wpaul@ctr.columbia.edu>
* Center for Telecommunications Research
* Columbia University, New York City
*
* This code is public domain. There is no copyright. There are no
* distribution or usage restrictions. There are no strings attached.
*
* Have a party.
*
* $Id$
*/
#include <stdio.h>
#ifndef _PATH_ETHERS
#define _PATH_ETHERS "/etc/ethers"
#endif
/*
* This should be defined in <netinet/if_ether.h> but it isn't.
*/
struct ether_addr {
unsigned char octet[6];
};
/*
* 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 (-1);
for (i=0; i<6; i++)
e->octet[i] = o[i];
return (0);
}
/*
* 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;
static char buf[BUFSIZ];
static struct ether_addr local_ether;
static char *local_host;
static char *result;
int resultlen, i;
extern int yp_get_default_domain();
extern int yp_match();
static char *yp_domain;
static char ether_a[BUFSIZ];
if ((fp = fopen(_PATH_ETHERS, "r")) == NULL) {
perror(_PATH_ETHERS);
return (-1);
}
while (fgets(buf,BUFSIZ,fp)) {
if (buf[0] == '+') {
if (yp_get_default_domain(&yp_domain))
return(-1);
sprintf(ether_a,"%x:%x:%x:%x:%x:%x",
e->octet[0], e->octet[1],
e->octet[2], e->octet[3],
e->octet[4], e->octet[5]);
if (yp_match(yp_domain, "ethers.byaddr", ether_a,
strlen(ether_a),&result, &resultlen))
return(-1);
if (ether_line(result, &local_ether,
&local_host) == 0) {
strcpy(hostname, (char *)&local_host);
return(0);
} else
return(-1);
}
if (ether_line(&buf, &local_ether, &local_host) == 0) {
for (i = 0; i < 6; i++)
if (local_ether.octet[i] != e->octet[i])
goto nomatch;
/* We have a match */
strcpy(hostname, (char *)&local_host);
fclose(fp);
return(0);
}
nomatch:
}
return (-1);
}
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