ntpsubs.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 284 行

#ifndef lint
static	char	*sccsid = "@(#)ntpsubs.c	4.1	(ULTRIX)	7/2/90";
#endif lint
/************************************************************************
 *									*
 *			Copyright (c) 1988-1990 by			*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/
#ifndef	lint
static char *RCSid = "$Source: /usr/users/louie/ntp/RCS/ntpsubs.c,v $ $Revision: 3.4.1.3 $ $Date: 89/05/18 18:33:50 $";
#endif	lint

/*
 *  $Log:	ntpsubs.c,v $
 * Revision 3.4.1.3  89/05/18  18:33:50  louie
 * Added support few a new type of unsigned long to double compiler brokenness,
 * called GENERIC_UNS_BUG.  If this is defined, then the unsigned long is
 * shifted right one bit, the high-order bit of the result is cleared, then
 * converted to a double.  The double is multiplied by 2.0, and the a 1.0 is
 * optionall added to it if the low order bit of the original unsigned long
 * was set.  Whew!
 * 
 * Revision 3.4.1.2  89/03/29  12:46:02  louie
 * Check for success sending query before trying to listen for answers.  Will 
 * catch case of no server running and an ICMP port unreachable being returned.
 * 
 * Revision 3.4.1.1  89/03/22  18:32:19  louie
 * patch3: Use new RCS headers.
 * 
 * Revision 3.4  89/03/17  18:37:18  louie
 * Latest test release.
 * 
 * Revision 3.3  89/03/15  14:20:03  louie
 * New baseline for next release.
 * 
 * Revision 3.2  89/03/07  18:29:22  louie
 * New version of UNIX NTP daemon based on the 6 March 1989 draft of the new
 * NTP protocol spec.  This module has mostly cosmetic changes.
 * 
 * Revision 3.1.1.1  89/02/15  08:59:27  louie
 * *** empty log message ***
 * 
 * 
 * Revision 3.1  89/01/30  14:43:18  louie
 * Second UNIX NTP test release.
 * 
 * Revision 3.0  88/12/12  15:58:59  louie
 * Test release of new UNIX NTP software.  This version should conform to the
 * revised NTP protocol specification.
 * 
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <syslog.h>

#include "ntp.h"

extern int errno;

#define	TRUE	1
#define	FALSE	0

/*
 *  The nice thing here is that the quantity is NEVER signed.
 */
double
ul_fixed_to_double(t)
	struct l_fixedpt *t;
{
	double a, b;
#ifdef	GENERIC_UNS_BUG
	register int i;

	i = ntohl(t->fraction);
	a = (long)((i >> 1) & 0x7fffffff);
	a *= 2.0;
	if (i & 1)
		a += 1.0;
	a = a / (4.294967296e9);	/* shift dec point over by 32 bits */
	i = ntohl(t->int_part);
	b = (long)((i >> 1) & 0x7fffffff);
	b *= 2.0;
	if (i & 1)
		b += 1.0;
#else	/* GENERIC_UNS_BUG */
	a = (unsigned long) ntohl(t->fraction);
#ifdef	VAX_COMPILER_FLT_BUG
	if (a < 0.0) a += 4.294967296e9;
#endif
	a = a / (4.294967296e9);/* shift dec point over by 32 bits */
	b = (unsigned long) ntohl(t->int_part);
#ifdef	VAX_COMPILER_FLT_BUG
	if (b < 0.0) b += 4.294967296e9;
#endif
#endif	/* GENERIC_UNS_BUG */
	return (a + b);
}

/*
 *  Here we have to worry about the high order bit being signed
 */

#if	0
double
l_fixed_to_double(t)
	struct l_fixedpt *t;
{
	double a,b;

	if (ntohl(t->int_part) & 0x80000000) {
		a = ntohl(~t->fraction);
#ifdef	VAX_COMPILER_FLT_BUG
		if (a < 0.0) a += 4.294967296e9;
#endif
		a = a / (4.294967296e9);
		b = ntohl(~t->int_part);
#ifdef	VAX_COMPILER_FLT_BUG
		if (b < 0.0) b += 4.294967296e9;
#endif
		a += b;
		a = -a;
	} else {
		a = ntohl(t->fraction);
#ifdef	VAX_COMPILER_FLT_BUG
		if (a < 0.0) a += 4.294967296e9;
#endif
		a = a / (4.294967296e9);
		b = ntohl(t->int_part);
#ifdef	VAX_COMPILER_FLT_BUG
		if (b < 0.0) b += 4.294967296e9;
#endif
		a += b;
	}
	return (a);
}
#endif

/*
 *  Here we have to worry about the high order bit being signed
 */
double
s_fixed_to_double(t)
	struct s_fixedpt *t;
{
	double a;

	if (ntohs(t->int_part) & 0x8000) {
		a = ntohs(~t->fraction & 0xFFFF);
		a = a / 65536.0;	/* shift dec point over by 16 bits */
		a +=  ntohs(~t->int_part & 0xFFFF);
		a = -a;
	} else {
		a = ntohs(t->fraction);
		a = a / 65536.0;	/* shift dec point over by 16 bits */
		a += ntohs(t->int_part);
	}
	return (a);
}

void
double_to_l_fixed(t, value)
	struct l_fixedpt *t;
	double value;
{
	double temp;

	if (value >= (double) 0.0) {
		t->int_part = value;
		temp = value - t->int_part;
		temp *= 4.294967296e9;
		t->fraction = temp;
		t->int_part = htonl(t->int_part);
		t->fraction = htonl(t->fraction);
	} else {
		value = -value;
		t->int_part = value;
		temp = value - t->int_part;
		temp *= 4.294967296e9;
		t->fraction = temp;
		t->int_part = htonl(~t->int_part);
		t->fraction = htonl(~t->fraction);
	}
}

void
double_to_s_fixed(t, value)
	struct s_fixedpt *t;
	double value;
{
	double temp;

	if (value >= (double) 0.0) {
		t->int_part = value;
		temp = value - t->int_part;
		temp *= 65536.0;
		t->fraction = temp;
		t->int_part = htons(t->int_part);
		t->fraction = htons(t->fraction);
	} else {
		value = -value;
		t->int_part = value;
		temp = value - t->int_part;
		temp *= 65536.0;
		t->fraction = temp;
		t->int_part = htons(~t->int_part);
		t->fraction = htons(~t->fraction);
	}
}
/*
	in the sun, trying to assign a float between 2^31 and 2^32
	results in the value 2^31.  Neither 4.2bsd nor VMS have this
	problem.  Reported it to Bob O'Brien of SMI
*/
#ifdef	SUN_FLT_BUG
tstamp(stampp, tvp)
	struct l_fixedpt *stampp;
	struct timeval *tvp;
{
	int tt;
	double dd;

	stampp->int_part = ntohl(JAN_1970 + tvp->tv_sec);
	dd = (float) tvp->tv_usec / 1000000.0;
	tt = dd * 2147483648.0;
	stampp->fraction = ntohl((tt << 1));
}
#else
tstamp(stampp, tvp)
	struct l_fixedpt *stampp;
	struct timeval *tvp;
{
	stampp->int_part = ntohl((u_long) (JAN_1970 + tvp->tv_sec));
	stampp->fraction = ntohl((u_long) ((float) tvp->tv_usec * 4294.967295));
}
#endif

/*
 * ntoa is similar to inet_ntoa, but cycles through a set of 8 buffers
 * so it can be invoked several times in a function parameter list.
 */

char *
ntoa (in_addr)
struct in_addr in_addr;
{
	static int i = 0;
	static char bufs[8][20];
	unsigned char *p = (unsigned char *) &in_addr.s_addr;

	i = (i + 1) % (sizeof bufs / sizeof bufs[0]);
	sprintf (bufs[i], "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
	return bufs[i];
}