159 lines
5.6 KiB
C
159 lines
5.6 KiB
C
/******************************************************************************
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* *
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* Copyright (c) David L. Mills 1993 *
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* *
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* Permission to use, copy, modify, and distribute this software and its *
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* documentation for any purpose and without fee is hereby granted, provided *
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* that the above copyright notice appears in all copies and that both the *
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* copyright notice and this permission notice appear in supporting *
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* documentation, and that the name University of Delaware not be used in *
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* advertising or publicity pertaining to distribution of the software *
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* without specific, written prior permission. The University of Delaware *
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* makes no representations about the suitability this software for any *
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* purpose. It is provided "as is" without express or implied warranty. *
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* *
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******************************************************************************/
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/*
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* Modification history timex.h
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*
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* 28 Nov 93 David L. Mills
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* Adjusted parameters to improve stability and increase poll interval
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*
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* 10 Oct 93 Torsten Duwe
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* Changed to ntp_timex.h (#ifdef'd HAVE_SYS_TIMEX_H)
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*
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* 17 Sep 93 David L. Mills
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* Created file
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*/
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/*
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* This header file defines the Network Time Protocol (NTP) interfaces
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* for user and daemon application programs. These are implemented using
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* private syscalls and data structures and require specific kernel
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* support.
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*
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* NAME
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* ntp_gettime - NTP user application interface
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*
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* SYNOPSIS
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* #include <sys/timex.h>
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*
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* int syscall(SYS_ntp_gettime, tptr)
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*
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* int SYS_ntp_gettime defined in syscall.h header file
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* struct ntptimeval *tptr pointer to ntptimeval structure
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*
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* NAME
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* ntp_adjtime - NTP daemon application interface
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*
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* SYNOPSIS
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* #include <sys/timex.h>
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*
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* int syscall(SYS_ntp_adjtime, mode, tptr)
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*
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* int SYS_ntp_adjtime defined in syscall.h header file
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* struct timex *tptr pointer to timex structure
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*
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*/
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#ifndef _NTP_TIMEX_H
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#define _NTP_TIMEX_H
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/*
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* Include system timex.h (if appropriate)
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*/
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#ifdef HAVE_SYS_TIMEX_H
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#include <sys/timex.h>
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#else /* provide definitions */
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#include <sys/syscall.h>
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extern int syscall P((int, void *, ...));
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#define ntp_gettime(t) syscall(SYS_ntp_gettime, (t))
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#define ntp_adjtime(t) syscall(SYS_ntp_adjtime, (t))
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/*
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* The following defines establish the engineering parameters of the PLL
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* model. The HZ variable establishes the timer interrupt frequency, 100 Hz
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* for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the
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* OSF/1 kernel. The SHIFT_HZ define expresses the same value as the
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* nearest power of two in order to avoid hardware multiply operations.
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*/
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#define SHIFT_HZ 7 /* log2(HZ) */
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/*
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* The SHIFT_KG and SHIFT_KF defines establish the damping of the PLL
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* and are chosen by analysis for a slightly underdamped convergence
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* characteristic. The MAXTC define establishes the maximum time constant
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* of the PLL. With the parameters given and the default time constant of
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* zero, the PLL will converge in about 15 minutes.
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*/
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#define SHIFT_KG 6 /* shift for phase increment */
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#define SHIFT_KF 16 /* shift for frequency increment */
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#define MAXTC 6 /* maximum time constant (shift) */
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/*
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* The SHIFT_SCALE define establishes the decimal point of the time_phase
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* variable which serves as a an extension to the low-order bits of the
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* system clock variable. The SHIFT_UPDATE define establishes the decimal
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* point of the time_offset variable which represents the current offset
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* with respect to standard time. The SHIFT_USEC define represents 1 us in
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* external units (shift), while the FINEUSEC define represents 1 us in
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* internal units.
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*/
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#define SHIFT_SCALE 23 /* shift for phase scale factor */
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#define SHIFT_UPDATE (SHIFT_KG + MAXTC) /* shift for offset scale factor */
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#define SHIFT_USEC 16 /* shift for 1 us in external units */
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#define FINEUSEC (1 << SHIFT_SCALE) /* 1 us in internal units */
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/*
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* Mode codes (timex.mode)
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*/
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#define ADJ_OFFSET 0x0001 /* time offset */
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#define ADJ_FREQUENCY 0x0002 /* frequency offset */
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#define ADJ_MAXERROR 0x0004 /* maximum time error */
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#define ADJ_ESTERROR 0x0008 /* estimated time error */
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#define ADJ_STATUS 0x0010 /* clock status */
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#define ADJ_TIMECONST 0x0020 /* pll time constant */
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/*
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* Clock command/status codes (timex.status)
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*/
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#define TIME_OK 0 /* clock synchronized */
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#define TIME_INS 1 /* insert leap second */
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#define TIME_DEL 2 /* delete leap second */
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#define TIME_OOP 3 /* leap second in progress */
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#define TIME_BAD 4 /* clock not synchronized */
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/*
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* NTP user interface - used to read kernel clock values
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* Note: maximum error = NTP synch distance = dispersion + delay / 2;
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* estimated error = NTP dispersion.
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*/
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struct ntptimeval {
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struct timeval time; /* current time */
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long maxerror; /* maximum error (usec) */
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long esterror; /* estimated error (usec) */
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};
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/*
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* NTP daemon interface - used to discipline kernel clock oscillator
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*/
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struct timex {
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int mode; /* mode selector */
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long offset; /* time offset (usec) */
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long frequency; /* frequency offset (scaled ppm) */
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long maxerror; /* maximum error (usec) */
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long esterror; /* estimated error (usec) */
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int status; /* clock command/status */
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long time_constant; /* pll time constant */
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long precision; /* clock precision (usec) (read only) */
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long tolerance; /* clock frequency tolerance (ppm)
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* (read only)
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*/
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};
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#endif /* HAVE_SYS_TIMEX_H */
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#endif /* _NTP_TIMEX_H */
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