1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1985, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #ifndef lint
33 #if 0
34 static char sccsid[] = "@(#)correct.c 8.1 (Berkeley) 6/6/93";
35 #endif
36 static const char rcsid[] =
37 "$FreeBSD$";
38 #endif /* not lint */
39
40 #include "globals.h"
41 #include <math.h>
42 #include <sys/types.h>
43 #include <sys/times.h>
44
45 static void adjclock(struct timeval *);
46
47 /*
48 * sends to the slaves the corrections for their clocks after fixing our
49 * own
50 */
51 void
correct(long avdelta)52 correct(long avdelta)
53 {
54 struct hosttbl *htp;
55 int corr;
56 struct timeval adjlocal, tmptv;
57 struct tsp to;
58 struct tsp *answer;
59
60 mstotvround(&adjlocal, avdelta);
61
62 for (htp = self.l_fwd; htp != &self; htp = htp->l_fwd) {
63 if (htp->delta != HOSTDOWN) {
64 corr = avdelta - htp->delta;
65 /* If the other machine is off in the weeds, set its time directly.
66 * If a slave gets the wrong day, the original code would simply
67 * fix the minutes. If you fix a network partition, you can get
68 * into such situations.
69 */
70 if (htp->need_set
71 || corr >= MAXADJ*1000
72 || corr <= -MAXADJ*1000) {
73 htp->need_set = 0;
74 (void)gettimeofday(&tmptv,0);
75 timevaladd(&tmptv, &adjlocal);
76 to.tsp_time.tv_sec = tmptv.tv_sec;
77 to.tsp_time.tv_usec = tmptv.tv_usec;
78 to.tsp_type = TSP_SETTIME;
79 } else {
80 tmptv.tv_sec = to.tsp_time.tv_sec;
81 tmptv.tv_usec = to.tsp_time.tv_usec;
82 mstotvround(&tmptv, corr);
83 to.tsp_time.tv_sec = tmptv.tv_sec;
84 to.tsp_time.tv_usec = tmptv.tv_usec;
85 to.tsp_type = TSP_ADJTIME;
86 }
87 (void)strcpy(to.tsp_name, hostname);
88 answer = acksend(&to, &htp->addr, htp->name,
89 TSP_ACK, 0, 0);
90 if (!answer) {
91 htp->delta = HOSTDOWN;
92 syslog(LOG_WARNING,
93 "no reply to time correction from %s",
94 htp->name);
95 if (++htp->noanswer >= LOSTHOST) {
96 if (trace) {
97 fprintf(fd,
98 "purging %s for not answering\n",
99 htp->name);
100 (void)fflush(fd);
101 }
102 htp = remmach(htp);
103 }
104 }
105 }
106 }
107
108 /*
109 * adjust our own clock now that we are not sending it out
110 */
111 adjclock(&adjlocal);
112 }
113
114
115 static void
adjclock(struct timeval * corr)116 adjclock(struct timeval *corr)
117 {
118 static int passes = 0;
119 static int smoother = 0;
120 long delta; /* adjustment in usec */
121 long ndelta;
122 struct timeval now;
123 struct timeval adj;
124
125 if (!timerisset(corr))
126 return;
127
128 adj = *corr;
129 if (adj.tv_sec < MAXADJ && adj.tv_sec > - MAXADJ) {
130 delta = adj.tv_sec*1000000 + adj.tv_usec;
131 /* If the correction is less than the minimum round
132 * trip time for an ICMP packet, and thus
133 * less than the likely error in the measurement,
134 * do not do the entire correction. Do half
135 * or a quarter of it.
136 */
137
138 if (delta > -MIN_ROUND*1000
139 && delta < MIN_ROUND*1000) {
140 if (smoother <= 4)
141 smoother++;
142 ndelta = delta >> smoother;
143 if (trace)
144 fprintf(fd,
145 "trimming delta %ld usec to %ld\n",
146 delta, ndelta);
147 adj.tv_usec = ndelta;
148 adj.tv_sec = 0;
149 } else if (smoother > 0) {
150 smoother--;
151 }
152 if (0 > adjtime(corr, 0)) {
153 syslog(LOG_ERR, "adjtime: %m");
154 }
155 if (passes > 1
156 && (delta < -BIG_ADJ || delta > BIG_ADJ)) {
157 smoother = 0;
158 passes = 0;
159 syslog(LOG_WARNING,
160 "large time adjustment of %+.3f sec",
161 delta/1000000.0);
162 }
163 } else {
164 syslog(LOG_WARNING,
165 "clock correction %jd sec too large to adjust",
166 (intmax_t)adj.tv_sec);
167 (void) gettimeofday(&now, 0);
168 timevaladd(&now, corr);
169 if (settimeofday(&now, 0) < 0)
170 syslog(LOG_ERR, "settimeofday: %m");
171 }
172 }
173
174
175 /* adjust the time in a message by the time it
176 * spent in the queue
177 */
178 void
adj_msg_time(struct tsp * msg,struct timeval * now)179 adj_msg_time(struct tsp *msg, struct timeval *now)
180 {
181 msg->tsp_time.tv_sec += (now->tv_sec - from_when.tv_sec);
182 msg->tsp_time.tv_usec += (now->tv_usec - from_when.tv_usec);
183
184 while (msg->tsp_time.tv_usec < 0) {
185 msg->tsp_time.tv_sec--;
186 msg->tsp_time.tv_usec += 1000000;
187 }
188 while (msg->tsp_time.tv_usec >= 1000000) {
189 msg->tsp_time.tv_sec++;
190 msg->tsp_time.tv_usec -= 1000000;
191 }
192 }
193