xref: /freebsd/sys/kern/kern_ntptime.c (revision 17ee9d00bc1ae1e598c38f25826f861e4bc6c3ce)
1 /******************************************************************************
2  *                                                                            *
3  * Copyright (c) David L. Mills 1993, 1994                                    *
4  *                                                                            *
5  * Permission to use, copy, modify, and distribute this software and its      *
6  * documentation for any purpose and without fee is hereby granted, provided  *
7  * that the above copyright notice appears in all copies and that both the    *
8  * copyright notice and this permission notice appear in supporting           *
9  * documentation, and that the name University of Delaware not be used in     *
10  * advertising or publicity pertaining to distribution of the software        *
11  * without specific, written prior permission.  The University of Delaware    *
12  * makes no representations about the suitability this software for any       *
13  * purpose.  It is provided "as is" without express or implied warranty.      *
14  *                                                                            *
15  ******************************************************************************/
16 
17 /*
18  * Modification history kern_ntptime.c
19  *
20  * 24 Mar 94	David L. Mills
21  *	Revised syscall interface to include new variables for PPS
22  *	time discipline.
23  *
24  * 14 Feb 94	David L. Mills
25  *	Added code for external clock
26  *
27  * 28 Nov 93	David L. Mills
28  *	Revised frequency scaling to conform with adjusted parameters
29  *
30  * 17 Sep 93	David L. Mills
31  *	Created file
32  */
33 /*
34  * ntp_gettime(), ntp_adjtime() - precision time interface for SunOS
35  * 4.1.1 and 4.1.3
36  *
37  * These routines consitute the Network Time Protocol (NTP) interfaces
38  * for user and daemon application programs. The ntp_gettime() routine
39  * provides the time, maximum error (synch distance) and estimated error
40  * (dispersion) to client user application programs. The ntp_adjtime()
41  * routine is used by the NTP daemon to adjust the system clock to an
42  * externally derived time. The time offset and related variables set by
43  * this routine are used by hardclock() to adjust the phase and
44  * frequency of the phase-lock loop which controls the system clock.
45  */
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/proc.h>
50 #include <sys/timex.h>
51 #include <vm/vm.h>
52 #include <sys/sysctl.h>
53 
54 /*
55  * The following variables are used by the hardclock() routine in the
56  * kern_clock.c module and are described in that module.
57  */
58 extern int time_state;		/* clock state */
59 extern int time_status;		/* clock status bits */
60 extern long time_offset;	/* time adjustment (us) */
61 extern long time_freq;		/* frequency offset (scaled ppm) */
62 extern long time_maxerror;	/* maximum error (us) */
63 extern long time_esterror;	/* estimated error (us) */
64 extern long time_constant;	/* pll time constant */
65 extern long time_precision;	/* clock precision (us) */
66 extern long time_tolerance;	/* frequency tolerance (scaled ppm) */
67 
68 #ifdef PPS_SYNC
69 /*
70  * The following variables are used only if the PPS signal discipline
71  * is configured in the kernel.
72  */
73 extern int pps_shift;		/* interval duration (s) (shift) */
74 extern long pps_freq;		/* pps frequency offset (scaled ppm) */
75 extern long pps_jitter;		/* pps jitter (us) */
76 extern long pps_stabil;		/* pps stability (scaled ppm) */
77 extern long pps_jitcnt;		/* jitter limit exceeded */
78 extern long pps_calcnt;		/* calibration intervals */
79 extern long pps_errcnt;		/* calibration errors */
80 extern long pps_stbcnt;		/* stability limit exceeded */
81 #endif /* PPS_SYNC */
82 
83 int
84 ntp_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
85 	   void *newp, size_t newlen, struct proc *p)
86 {
87 	struct timeval atv;
88 	struct ntptimeval ntv;
89 	int s;
90 
91 	/* All names at this level are terminal. */
92 	if (namelen != 1) {
93 		return ENOTDIR;
94 	}
95 
96 	if (name[0] != NTP_PLL_GETTIME) {
97 		return EOPNOTSUPP;
98 	}
99 
100 	s = splclock();
101 #ifdef EXT_CLOCK
102 	/*
103 	 * The microtime() external clock routine returns a
104 	 * status code. If less than zero, we declare an error
105 	 * in the clock status word and return the kernel
106 	 * (software) time variable. While there are other
107 	 * places that call microtime(), this is the only place
108 	 * that matters from an application point of view.
109 	 */
110 	if (microtime(&atv) < 0) {
111 		time_status |= STA_CLOCKERR;
112 		ntv.time = time;
113 	} else {
114 		time_status &= ~STA_CLOCKERR;
115 	}
116 #else /* EXT_CLOCK */
117 	microtime(&atv);
118 #endif /* EXT_CLOCK */
119 	ntv.time = atv;
120 	ntv.maxerror = time_maxerror;
121 	ntv.esterror = time_esterror;
122 	splx(s);
123 
124 	ntv.time_state = time_state;
125 
126 	/*
127 	 * Status word error decode. If any of these conditions
128 	 * occur, an error is returned, instead of the status
129 	 * word. Most applications will care only about the fact
130 	 * the system clock may not be trusted, not about the
131 	 * details.
132 	 *
133 	 * Hardware or software error
134 	 */
135 	if (time_status & (STA_UNSYNC | STA_CLOCKERR)) {
136 		ntv.time_state = TIME_ERROR;
137 	}
138 
139 	/*
140 	 * PPS signal lost when either time or frequency
141 	 * synchronization requested
142 	 */
143 	if (time_status & (STA_PPSFREQ | STA_PPSTIME) &&
144 	    !(time_status & STA_PPSSIGNAL)) {
145 		ntv.time_state = TIME_ERROR;
146 	}
147 
148 	/*
149 	 * PPS jitter exceeded when time synchronization
150 	 * requested
151 	 */
152 	if (time_status & STA_PPSTIME &&
153 	    time_status & STA_PPSJITTER) {
154 		ntv.time_state = TIME_ERROR;
155 	}
156 
157 	/*
158 	 * PPS wander exceeded or calibration error when
159 	 * frequency synchronization requested
160 	 */
161 	if (time_status & STA_PPSFREQ &&
162 	    time_status & (STA_PPSWANDER | STA_PPSERROR)) {
163 		ntv.time_state = TIME_ERROR;
164 	}
165 	return(sysctl_rdstruct(oldp, oldlenp, newp, &ntv, sizeof ntv));
166 }
167 
168 /*
169  * ntp_adjtime() - NTP daemon application interface
170  */
171 struct ntp_adjtime_args {
172   struct timex *tp;
173 };
174 
175 int
176 ntp_adjtime(struct proc *p, struct ntp_adjtime_args *uap, int *retval)
177 {
178 	struct timex ntv;
179 	int modes;
180 	int s;
181 	int error;
182 
183 	error = copyin((caddr_t)uap->tp, (caddr_t)&ntv, sizeof(ntv));
184 	if (error)
185 		return error;
186 
187 	/*
188 	 * Update selected clock variables - only the superuser can
189 	 * change anything. Note that there is no error checking here on
190 	 * the assumption the superuser should know what it is doing.
191 	 */
192 	modes = ntv.modes;
193 	if ((modes != 0)
194 	    && (error = suser(p->p_cred->pc_ucred, &p->p_acflag)))
195 		return error;
196 
197 	s = splclock();
198 	if (modes & MOD_FREQUENCY)
199 #ifdef PPS_SYNC
200 		time_freq = ntv.freq - pps_freq;
201 #else /* PPS_SYNC */
202 		time_freq = ntv.freq;
203 #endif /* PPS_SYNC */
204 	if (modes & MOD_MAXERROR)
205 		time_maxerror = ntv.maxerror;
206 	if (modes & MOD_ESTERROR)
207 		time_esterror = ntv.esterror;
208 	if (modes & MOD_STATUS) {
209 		time_status &= STA_RONLY;
210 		time_status |= ntv.status & ~STA_RONLY;
211 	}
212 	if (modes & MOD_TIMECONST)
213 		time_constant = ntv.constant;
214 	if (modes & MOD_OFFSET)
215 		hardupdate(ntv.offset);
216 
217 	/*
218 	 * Retrieve all clock variables
219 	 */
220 	if (time_offset < 0)
221 		ntv.offset = -(-time_offset >> SHIFT_UPDATE);
222 	else
223 		ntv.offset = time_offset >> SHIFT_UPDATE;
224 #ifdef PPS_SYNC
225 	ntv.freq = time_freq + pps_freq;
226 #else /* PPS_SYNC */
227 	ntv.freq = time_freq;
228 #endif /* PPS_SYNC */
229 	ntv.maxerror = time_maxerror;
230 	ntv.esterror = time_esterror;
231 	ntv.status = time_status;
232 	ntv.constant = time_constant;
233 	ntv.precision = time_precision;
234 	ntv.tolerance = time_tolerance;
235 #ifdef PPS_SYNC
236 	ntv.shift = pps_shift;
237 	ntv.ppsfreq = pps_freq;
238 	ntv.jitter = pps_jitter >> PPS_AVG;
239 	ntv.stabil = pps_stabil;
240 	ntv.calcnt = pps_calcnt;
241 	ntv.errcnt = pps_errcnt;
242 	ntv.jitcnt = pps_jitcnt;
243 	ntv.stbcnt = pps_stbcnt;
244 #endif /* PPS_SYNC */
245 	(void)splx(s);
246 
247 	error = copyout((caddr_t)&ntv, (caddr_t)uap->tp, sizeof(ntv));
248 	if (!error) {
249 		/*
250 		 * Status word error decode. See comments in
251 		 * ntp_gettime() routine.
252 		 */
253 		retval[0] = time_state;
254 		if (time_status & (STA_UNSYNC | STA_CLOCKERR))
255 			retval[0] = TIME_ERROR;
256 		if (time_status & (STA_PPSFREQ | STA_PPSTIME) &&
257 		    !(time_status & STA_PPSSIGNAL))
258 			retval[0] = TIME_ERROR;
259 		if (time_status & STA_PPSTIME &&
260 		    time_status & STA_PPSJITTER)
261 			retval[0] = TIME_ERROR;
262 		if (time_status & STA_PPSFREQ &&
263 		    time_status & (STA_PPSWANDER | STA_PPSERROR))
264 			retval[0] = TIME_ERROR;
265 	}
266 	return error;
267 }
268 
269 
270