NetBSD/lib/libntp/numtohost.c

/*	$NetBSD: numtohost.c,v 1.3 1999/07/02 15:58:36 simonb Exp $	*/

/*
 * numtohost - convert network number to host name.
 */
#include <netdb.h>

#include "ntp_fp.h"
#include "ntp_stdlib.h"
#include "lib_strbuf.h"

#define	LOOPBACKNET	0x7f000000
#define	LOOPBACKHOST	0x7f000001
#define	LOOPBACKNETMASK	0xff000000

char *
numtohost(netnum)
	u_int32 netnum;
{
	char *bp;
	struct hostent *hp;

	/*
	 * This is really gross, but saves lots of hanging looking for
	 * hostnames for the radio clocks.  Don't bother looking up
	 * addresses on the loopback network except for the loopback
	 * host itself.
	 */
	if ((((ntohl(netnum) & LOOPBACKNETMASK) == LOOPBACKNET)
	    && (ntohl(netnum) != LOOPBACKHOST))
	    || ((hp = gethostbyaddr((char *)&netnum, sizeof netnum, AF_INET))
	      == 0))
		return numtoa(netnum);

	LIB_GETBUF(bp);

	bp[LIB_BUFLENGTH-1] = '\0';
	(void) strncpy(bp, hp->h_name, LIB_BUFLENGTH-1);
	return bp;
}