1/*-
2 * Copyright (c) 1985, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#ifndef lint
31#if 0
32static char sccsid[] = "@(#)correct.c	8.1 (Berkeley) 6/6/93";
33#endif
34static const char rcsid[] =
35  "$FreeBSD$";
36#endif /* not lint */
37
38#include "globals.h"
39#include <math.h>
40#include <sys/types.h>
41#include <sys/times.h>
42
43static void adjclock(struct timeval *);
44
45/*
46 * sends to the slaves the corrections for their clocks after fixing our
47 * own
48 */
49void
50correct(long avdelta)
51{
52	struct hosttbl *htp;
53	int corr;
54	struct timeval adjlocal, tmptv;
55	struct tsp to;
56	struct tsp *answer;
57
58	mstotvround(&adjlocal, avdelta);
59
60	for (htp = self.l_fwd; htp != &self; htp = htp->l_fwd) {
61		if (htp->delta != HOSTDOWN)  {
62			corr = avdelta - htp->delta;
63/* If the other machine is off in the weeds, set its time directly.
64 *	If a slave gets the wrong day, the original code would simply
65 *	fix the minutes.  If you fix a network partition, you can get
66 *	into such situations.
67 */
68			if (htp->need_set
69			    || corr >= MAXADJ*1000
70			    || corr <= -MAXADJ*1000) {
71				htp->need_set = 0;
72				(void)gettimeofday(&tmptv,0);
73				timevaladd(&tmptv, &adjlocal);
74				to.tsp_time.tv_sec = tmptv.tv_sec;
75				to.tsp_time.tv_usec = tmptv.tv_usec;
76				to.tsp_type = TSP_SETTIME;
77			} else {
78				tmptv.tv_sec = to.tsp_time.tv_sec;
79				tmptv.tv_usec = to.tsp_time.tv_usec;
80				mstotvround(&tmptv, corr);
81				to.tsp_time.tv_sec = tmptv.tv_sec;
82				to.tsp_time.tv_usec = tmptv.tv_usec;
83				to.tsp_type = TSP_ADJTIME;
84			}
85			(void)strcpy(to.tsp_name, hostname);
86			answer = acksend(&to, &htp->addr, htp->name,
87					 TSP_ACK, 0, 0);
88			if (!answer) {
89				htp->delta = HOSTDOWN;
90				syslog(LOG_WARNING,
91				       "no reply to time correction from %s",
92				       htp->name);
93				if (++htp->noanswer >= LOSTHOST) {
94					if (trace) {
95						fprintf(fd,
96					     "purging %s for not answering\n",
97							htp->name);
98						(void)fflush(fd);
99					}
100					htp = remmach(htp);
101				}
102			}
103		}
104	}
105
106	/*
107	 * adjust our own clock now that we are not sending it out
108	 */
109	adjclock(&adjlocal);
110}
111
112
113static void
114adjclock(struct timeval *corr)
115{
116	static int passes = 0;
117	static int smoother = 0;
118	long delta;			/* adjustment in usec */
119	long ndelta;
120	struct timeval now;
121	struct timeval adj;
122
123	if (!timerisset(corr))
124		return;
125
126	adj = *corr;
127	if (adj.tv_sec < MAXADJ && adj.tv_sec > - MAXADJ) {
128		delta = adj.tv_sec*1000000 + adj.tv_usec;
129		/* If the correction is less than the minimum round
130		 *	trip time for an ICMP packet, and thus
131		 *	less than the likely error in the measurement,
132		 *	do not do the entire correction.  Do half
133		 *	or a quarter of it.
134		 */
135
136		if (delta > -MIN_ROUND*1000
137		    && delta < MIN_ROUND*1000) {
138			if (smoother <= 4)
139				smoother++;
140			ndelta = delta >> smoother;
141			if (trace)
142				fprintf(fd,
143					"trimming delta %ld usec to %ld\n",
144					delta, ndelta);
145			adj.tv_usec = ndelta;
146			adj.tv_sec = 0;
147		} else if (smoother > 0) {
148			smoother--;
149		}
150		if (0 > adjtime(corr, 0)) {
151			syslog(LOG_ERR, "adjtime: %m");
152		}
153		if (passes > 1
154		    && (delta < -BIG_ADJ || delta > BIG_ADJ)) {
155			smoother = 0;
156			passes = 0;
157			syslog(LOG_WARNING,
158			       "large time adjustment of %+.3f sec",
159			       delta/1000000.0);
160		}
161	} else {
162		syslog(LOG_WARNING,
163		       "clock correction %jd sec too large to adjust",
164		       (intmax_t)adj.tv_sec);
165		(void) gettimeofday(&now, 0);
166		timevaladd(&now, corr);
167		if (settimeofday(&now, 0) < 0)
168			syslog(LOG_ERR, "settimeofday: %m");
169	}
170}
171
172
173/* adjust the time in a message by the time it
174 *	spent in the queue
175 */
176void
177adj_msg_time(struct tsp *msg, struct timeval *now)
178{
179	msg->tsp_time.tv_sec += (now->tv_sec - from_when.tv_sec);
180	msg->tsp_time.tv_usec += (now->tv_usec - from_when.tv_usec);
181
182	while (msg->tsp_time.tv_usec < 0) {
183		msg->tsp_time.tv_sec--;
184		msg->tsp_time.tv_usec += 1000000;
185	}
186	while (msg->tsp_time.tv_usec >= 1000000) {
187		msg->tsp_time.tv_sec++;
188		msg->tsp_time.tv_usec -= 1000000;
189	}
190}
191