/contrib/ntp/ntpd/refclock_datum.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 877 lines · 425 code · 168 blank · 284 comment · 51 complexity · 9e0de6bb2668e65794a9722f23533ea2 MD5 · raw file
- /*
- ** refclock_datum - clock driver for the Datum Programmable Time Server
- **
- ** Important note: This driver assumes that you have termios. If you have
- ** a system that does not have termios, you will have to modify this driver.
- **
- ** Sorry, I have only tested this driver on SUN and HP platforms.
- */
- #ifdef HAVE_CONFIG_H
- # include <config.h>
- #endif
- #if defined(REFCLOCK) && defined(CLOCK_DATUM)
- /*
- ** Include Files
- */
- #include "ntpd.h"
- #include "ntp_io.h"
- #include "ntp_refclock.h"
- #include "ntp_unixtime.h"
- #include "ntp_stdlib.h"
- #include <stdio.h>
- #include <ctype.h>
- #if defined(HAVE_BSD_TTYS)
- #include <sgtty.h>
- #endif /* HAVE_BSD_TTYS */
- #if defined(HAVE_SYSV_TTYS)
- #include <termio.h>
- #endif /* HAVE_SYSV_TTYS */
- #if defined(HAVE_TERMIOS)
- #include <termios.h>
- #endif
- #if defined(STREAM)
- #include <stropts.h>
- #if defined(WWVBCLK)
- #include <sys/clkdefs.h>
- #endif /* WWVBCLK */
- #endif /* STREAM */
- #include "ntp_stdlib.h"
- /*
- ** This driver supports the Datum Programmable Time System (PTS) clock.
- ** The clock works in very straight forward manner. When it receives a
- ** time code request (e.g., the ascii string "//k/mn"), it responds with
- ** a seven byte BCD time code. This clock only responds with a
- ** time code after it first receives the "//k/mn" message. It does not
- ** periodically send time codes back at some rate once it is started.
- ** the returned time code can be broken down into the following fields.
- **
- ** _______________________________
- ** Bit Index | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
- ** ===============================
- ** byte 0: | - - - - | H D |
- ** ===============================
- ** byte 1: | T D | U D |
- ** ===============================
- ** byte 2: | - - | T H | U H |
- ** ===============================
- ** byte 3: | - | T M | U M |
- ** ===============================
- ** byte 4: | - | T S | U S |
- ** ===============================
- ** byte 5: | t S | h S |
- ** ===============================
- ** byte 6: | m S | - - - - |
- ** ===============================
- **
- ** In the table above:
- **
- ** "-" means don't care
- ** "H D", "T D", and "U D" means Hundreds, Tens, and Units of Days
- ** "T H", and "UH" means Tens and Units of Hours
- ** "T M", and "U M" means Tens and Units of Minutes
- ** "T S", and "U S" means Tens and Units of Seconds
- ** "t S", "h S", and "m S" means tenths, hundredths, and thousandths
- ** of seconds
- **
- ** The Datum PTS communicates throught the RS232 port on your machine.
- ** Right now, it assumes that you have termios. This driver has been tested
- ** on SUN and HP workstations. The Datum PTS supports various IRIG and
- ** NASA input codes. This driver assumes that the name of the device is
- ** /dev/datum. You will need to make a soft link to your RS232 device or
- ** create a new driver to use this refclock.
- */
- /*
- ** Datum PTS defines
- */
- /*
- ** Note that if GMT is defined, then the Datum PTS must use Greenwich
- ** time. Otherwise, this driver allows the Datum PTS to use the current
- ** wall clock for its time. It determines the time zone offset by minimizing
- ** the error after trying several time zone offsets. If the Datum PTS
- ** time is Greenwich time and GMT is not defined, everything should still
- ** work since the time zone will be found to be 0. What this really means
- ** is that your system time (at least to start with) must be within the
- ** correct time by less than +- 30 minutes. The default is for GMT to not
- ** defined. If you really want to force GMT without the funny +- 30 minute
- ** stuff then you must define (uncomment) GMT below.
- */
- /*
- #define GMT
- #define DEBUG_DATUM_PTC
- #define LOG_TIME_ERRORS
- */
- #define PRECISION (-10) /* precision assumed 1/1024 ms */
- #define REFID "DATM" /* reference id */
- #define DATUM_DISPERSION 0 /* fixed dispersion = 0 ms */
- #define DATUM_MAX_ERROR 0.100 /* limits on sigma squared */
- #define DATUM_DEV "/dev/datum" /* device name */
- #define DATUM_MAX_ERROR2 (DATUM_MAX_ERROR*DATUM_MAX_ERROR)
- /*
- ** The Datum PTS structure
- */
- /*
- ** I don't use a fixed array of MAXUNITS like everyone else just because
- ** I don't like to program that way. Sorry if this bothers anyone. I assume
- ** that you can use any id for your unit and I will search for it in a
- ** dynamic array of units until I find it. I was worried that users might
- ** enter a bad id in their configuration file (larger than MAXUNITS) and
- ** besides, it is just cleaner not to have to assume that you have a fixed
- ** number of anything in a program.
- */
- struct datum_pts_unit {
- struct peer *peer; /* peer used by ntp */
- struct refclockio io; /* io structure used by ntp */
- int PTS_fd; /* file descriptor for PTS */
- u_int unit; /* id for unit */
- u_long timestarted; /* time started */
- l_fp lastrec; /* time tag for the receive time (system) */
- l_fp lastref; /* reference time (Datum time) */
- u_long yearstart; /* the year that this clock started */
- int coderecv; /* number of time codes received */
- int day; /* day */
- int hour; /* hour */
- int minute; /* minutes */
- int second; /* seconds */
- int msec; /* miliseconds */
- int usec; /* miliseconds */
- u_char leap; /* funny leap character code */
- char retbuf[8]; /* returned time from the datum pts */
- char nbytes; /* number of bytes received from datum pts */
- double sigma2; /* average squared error (roughly) */
- int tzoff; /* time zone offest from GMT */
- };
- /*
- ** PTS static constant variables for internal use
- */
- static char TIME_REQUEST[6]; /* request message sent to datum for time */
- static int nunits; /* number of active units */
- static struct datum_pts_unit
- **datum_pts_unit; /* dynamic array of datum PTS structures */
- /*
- ** Callback function prototypes that ntpd needs to know about.
- */
- static int datum_pts_start P((int, struct peer *));
- static void datum_pts_shutdown P((int, struct peer *));
- static void datum_pts_poll P((int, struct peer *));
- static void datum_pts_control P((int, struct refclockstat *,
- struct refclockstat *, struct peer *));
- static void datum_pts_init P((void));
- static void datum_pts_buginfo P((int, struct refclockbug *, struct peer *));
- /*
- ** This is the call back function structure that ntpd actually uses for
- ** this refclock.
- */
- struct refclock refclock_datum = {
- datum_pts_start, /* start up a new Datum refclock */
- datum_pts_shutdown, /* shutdown a Datum refclock */
- datum_pts_poll, /* sends out the time request */
- datum_pts_control, /* not used */
- datum_pts_init, /* initialization (called first) */
- datum_pts_buginfo, /* not used */
- NOFLAGS /* we are not setting any special flags */
- };
- /*
- ** The datum_pts_receive callback function is handled differently from the
- ** rest. It is passed to the ntpd io data structure. Basically, every
- ** 64 seconds, the datum_pts_poll() routine is called. It sends out the time
- ** request message to the Datum Programmable Time System. Then, ntpd
- ** waits on a select() call to receive data back. The datum_pts_receive()
- ** function is called as data comes back. We expect a seven byte time
- ** code to be returned but the datum_pts_receive() function may only get
- ** a few bytes passed to it at a time. In other words, this routine may
- ** get called by the io stuff in ntpd a few times before we get all seven
- ** bytes. Once the last byte is received, we process it and then pass the
- ** new time measurement to ntpd for updating the system time. For now,
- ** there is no 3 state filtering done on the time measurements. The
- ** jitter may be a little high but at least for its current use, it is not
- ** a problem. We have tried to keep things as simple as possible. This
- ** clock should not jitter more than 1 or 2 mseconds at the most once
- ** things settle down. It is important to get the right drift calibrated
- ** in the ntpd.drift file as well as getting the right tick set up right
- ** using tickadj for SUNs. Tickadj is not used for the HP but you need to
- ** remember to bring up the adjtime daemon because HP does not support
- ** the adjtime() call.
- */
- static void datum_pts_receive P((struct recvbuf *));
- /*......................................................................*/
- /* datum_pts_start - start up the datum PTS. This means open the */
- /* RS232 device and set up the data structure for my unit. */
- /*......................................................................*/
- static int
- datum_pts_start(
- int unit,
- struct peer *peer
- )
- {
- struct datum_pts_unit **temp_datum_pts_unit;
- struct datum_pts_unit *datum_pts;
- int fd;
- #ifdef HAVE_TERMIOS
- struct termios arg;
- #endif
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Starting Datum PTS unit %d\n", unit);
- #endif
- /*
- ** Open the Datum PTS device
- */
- fd = open(DATUM_DEV, O_RDWR);
- if (fd < 0) {
- msyslog(LOG_ERR, "Datum_PTS: open(\"%s\", O_RDWR) failed: %m", DATUM_DEV);
- return 0;
- }
- /*
- ** Create the memory for the new unit
- */
- temp_datum_pts_unit = (struct datum_pts_unit **)
- malloc((nunits+1)*sizeof(struct datum_pts_unit *));
- if (nunits > 0) memcpy(temp_datum_pts_unit, datum_pts_unit,
- nunits*sizeof(struct datum_pts_unit *));
- free(datum_pts_unit);
- datum_pts_unit = temp_datum_pts_unit;
- datum_pts_unit[nunits] = (struct datum_pts_unit *)
- malloc(sizeof(struct datum_pts_unit));
- datum_pts = datum_pts_unit[nunits];
- datum_pts->unit = unit; /* set my unit id */
- datum_pts->yearstart = 0; /* initialize the yearstart to 0 */
- datum_pts->sigma2 = 0.0; /* initialize the sigma2 to 0 */
- datum_pts->PTS_fd = fd;
- fcntl(datum_pts->PTS_fd, F_SETFL, 0); /* clear the descriptor flags */
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Opening RS232 port with file descriptor %d\n",
- datum_pts->PTS_fd);
- #endif
- /*
- ** Set up the RS232 terminal device information. Note that we assume that
- ** we have termios. This code has only been tested on SUNs and HPs. If your
- ** machine does not have termios this driver cannot be initialized. You can change this
- ** if you want by editing this source. Please give the changes back to the
- ** ntp folks so that it can become part of their regular distribution.
- */
- #ifdef HAVE_TERMIOS
- arg.c_iflag = IGNBRK;
- arg.c_oflag = 0;
- arg.c_cflag = B9600 | CS8 | CREAD | PARENB | CLOCAL;
- arg.c_lflag = 0;
- arg.c_cc[VMIN] = 0; /* start timeout timer right away (not used) */
- arg.c_cc[VTIME] = 30; /* 3 second timout on reads (not used) */
- tcsetattr(datum_pts->PTS_fd, TCSANOW, &arg);
- #else
- msyslog(LOG_ERR, "Datum_PTS: Termios not supported in this driver");
- (void)close(datum_pts->PTS_fd);
- peer->precision = PRECISION;
- pp->clockdesc = DESCRIPTION;
- memcpy((char *)&pp->refid, REFID, 4);
- return 0;
- #endif
- /*
- ** Initialize the ntpd IO structure
- */
- datum_pts->peer = peer;
- datum_pts->io.clock_recv = datum_pts_receive;
- datum_pts->io.srcclock = (caddr_t)datum_pts;
- datum_pts->io.datalen = 0;
- datum_pts->io.fd = datum_pts->PTS_fd;
- if (!io_addclock(&(datum_pts->io))) {
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Problem adding clock\n");
- #endif
- msyslog(LOG_ERR, "Datum_PTS: Problem adding clock");
- (void)close(datum_pts->PTS_fd);
- return 0;
- }
- /*
- ** Now add one to the number of units and return a successful code
- */
- nunits++;
- return 1;
- }
- /*......................................................................*/
- /* datum_pts_shutdown - this routine shuts doen the device and */
- /* removes the memory for the unit. */
- /*......................................................................*/
- static void
- datum_pts_shutdown(
- int unit,
- struct peer *peer
- )
- {
- int i,j;
- struct datum_pts_unit **temp_datum_pts_unit;
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Shutdown Datum PTS\n");
- #endif
- msyslog(LOG_ERR, "Datum_PTS: Shutdown Datum PTS");
- /*
- ** First we have to find the right unit (i.e., the one with the same id).
- ** We do this by looping through the dynamic array of units intil we find
- ** it. Note, that I don't simply use an array with a maximimum number of
- ** Datum PTS units. Everything is completely dynamic.
- */
- for (i=0; i<nunits; i++) {
- if (datum_pts_unit[i]->unit == unit) {
- /*
- ** We found the unit so close the file descriptor and free up the memory used
- ** by the structure.
- */
- io_closeclock(&datum_pts_unit[i]->io);
- close(datum_pts_unit[i]->PTS_fd);
- free(datum_pts_unit[i]);
- /*
- ** Now clean up the datum_pts_unit dynamic array so that there are no holes.
- ** This may mean moving pointers around, etc., to keep things compact.
- */
- if (nunits > 1) {
- temp_datum_pts_unit = (struct datum_pts_unit **)
- malloc((nunits-1)*sizeof(struct datum_pts_unit *));
- if (i!= 0) memcpy(temp_datum_pts_unit, datum_pts_unit,
- i*sizeof(struct datum_pts_unit *));
- for (j=i+1; j<nunits; j++) {
- temp_datum_pts_unit[j-1] = datum_pts_unit[j];
- }
- free(datum_pts_unit);
- datum_pts_unit = temp_datum_pts_unit;
- }else{
- free(datum_pts_unit);
- datum_pts_unit = NULL;
- }
- return;
- }
- }
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Error, could not shut down unit %d\n",unit);
- #endif
- msyslog(LOG_ERR, "Datum_PTS: Could not shut down Datum PTS unit %d",unit);
- }
- /*......................................................................*/
- /* datum_pts_poll - this routine sends out the time request to the */
- /* Datum PTS device. The time will be passed back in the */
- /* datum_pts_receive() routine. */
- /*......................................................................*/
- static void
- datum_pts_poll(
- int unit,
- struct peer *peer
- )
- {
- int i;
- int unit_index;
- int error_code;
- struct datum_pts_unit *datum_pts;
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Poll Datum PTS\n");
- #endif
- /*
- ** Find the right unit and send out a time request once it is found.
- */
- unit_index = -1;
- for (i=0; i<nunits; i++) {
- if (datum_pts_unit[i]->unit == unit) {
- unit_index = i;
- datum_pts = datum_pts_unit[i];
- error_code = write(datum_pts->PTS_fd, TIME_REQUEST, 6);
- if (error_code != 6) perror("TIME_REQUEST");
- datum_pts->nbytes = 0;
- break;
- }
- }
- /*
- ** Print out an error message if we could not find the right unit.
- */
- if (unit_index == -1) {
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Error, could not poll unit %d\n",unit);
- #endif
- msyslog(LOG_ERR, "Datum_PTS: Could not poll unit %d",unit);
- return;
- }
- }
- /*......................................................................*/
- /* datum_pts_control - not used */
- /*......................................................................*/
- static void
- datum_pts_control(
- int unit,
- struct refclockstat *in,
- struct refclockstat *out,
- struct peer *peer
- )
- {
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Control Datum PTS\n");
- #endif
- }
- /*......................................................................*/
- /* datum_pts_init - initializes things for all possible Datum */
- /* time code generators that might be used. In practice, this is */
- /* only called once at the beginning before anything else is */
- /* called. */
- /*......................................................................*/
- static void
- datum_pts_init(void)
- {
- /* */
- /*...... open up the log file if we are debugging ......................*/
- /* */
- /*
- ** Open up the log file if we are debugging. For now, send data out to the
- ** screen (stdout).
- */
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Init Datum PTS\n");
- #endif
- /*
- ** Initialize the time request command string. This is the only message
- ** that we ever have to send to the Datum PTS (although others are defined).
- */
- memcpy(TIME_REQUEST, "//k/mn",6);
- /*
- ** Initialize the number of units to 0 and set the dynamic array of units to
- ** NULL since there are no units defined yet.
- */
- datum_pts_unit = NULL;
- nunits = 0;
- }
- /*......................................................................*/
- /* datum_pts_buginfo - not used */
- /*......................................................................*/
- static void
- datum_pts_buginfo(
- int unit,
- register struct refclockbug *bug,
- register struct peer *peer
- )
- {
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Buginfo Datum PTS\n");
- #endif
- }
- /*......................................................................*/
- /* datum_pts_receive - receive the time buffer that was read in */
- /* by the ntpd io handling routines. When 7 bytes have been */
- /* received (it may take several tries before all 7 bytes are */
- /* received), then the time code must be unpacked and sent to */
- /* the ntpd clock_receive() routine which causes the systems */
- /* clock to be updated (several layers down). */
- /*......................................................................*/
- static void
- datum_pts_receive(
- struct recvbuf *rbufp
- )
- {
- int i;
- l_fp tstmp;
- struct datum_pts_unit *datum_pts;
- char *dpt;
- int dpend;
- int tzoff;
- int timerr;
- double ftimerr, abserr;
- #ifdef DEBUG_DATUM_PTC
- double dispersion;
- #endif
- int goodtime;
- /*double doffset;*/
- /*
- ** Get the time code (maybe partial) message out of the rbufp buffer.
- */
- datum_pts = (struct datum_pts_unit *)rbufp->recv_srcclock;
- dpt = (char *)&rbufp->recv_space;
- dpend = rbufp->recv_length;
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Receive Datum PTS: %d bytes\n", dpend);
- #endif
- /* */
- /*...... save the ntp system time when the first byte is received ......*/
- /* */
- /*
- ** Save the ntp system time when the first byte is received. Note that
- ** because it may take several calls to this routine before all seven
- ** bytes of our return message are finally received by the io handlers in
- ** ntpd, we really do want to use the time tag when the first byte is
- ** received to reduce the jitter.
- */
- if (datum_pts->nbytes == 0) {
- datum_pts->lastrec = rbufp->recv_time;
- }
- /*
- ** Increment our count to the number of bytes received so far. Return if we
- ** haven't gotten all seven bytes yet.
- */
- for (i=0; i<dpend; i++) {
- datum_pts->retbuf[datum_pts->nbytes+i] = dpt[i];
- }
- datum_pts->nbytes += dpend;
- if (datum_pts->nbytes != 7) {
- return;
- }
- /*
- ** Convert the seven bytes received in our time buffer to day, hour, minute,
- ** second, and msecond values. The usec value is not used for anything
- ** currently. It is just the fractional part of the time stored in units
- ** of microseconds.
- */
- datum_pts->day = 100*(datum_pts->retbuf[0] & 0x0f) +
- 10*((datum_pts->retbuf[1] & 0xf0)>>4) +
- (datum_pts->retbuf[1] & 0x0f);
- datum_pts->hour = 10*((datum_pts->retbuf[2] & 0x30)>>4) +
- (datum_pts->retbuf[2] & 0x0f);
- datum_pts->minute = 10*((datum_pts->retbuf[3] & 0x70)>>4) +
- (datum_pts->retbuf[3] & 0x0f);
- datum_pts->second = 10*((datum_pts->retbuf[4] & 0x70)>>4) +
- (datum_pts->retbuf[4] & 0x0f);
- datum_pts->msec = 100*((datum_pts->retbuf[5] & 0xf0) >> 4) +
- 10*(datum_pts->retbuf[5] & 0x0f) +
- ((datum_pts->retbuf[6] & 0xf0)>>4);
- datum_pts->usec = 1000*datum_pts->msec;
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("day %d, hour %d, minute %d, second %d, msec %d\n",
- datum_pts->day,
- datum_pts->hour,
- datum_pts->minute,
- datum_pts->second,
- datum_pts->msec);
- #endif
- /*
- ** Get the GMT time zone offset. Note that GMT should be zero if the Datum
- ** reference time is using GMT as its time base. Otherwise we have to
- ** determine the offset if the Datum PTS is using time of day as its time
- ** base.
- */
- goodtime = 0; /* We are not sure about the time and offset yet */
- #ifdef GMT
- /*
- ** This is the case where the Datum PTS is using GMT so there is no time
- ** zone offset.
- */
- tzoff = 0; /* set time zone offset to 0 */
- #else
- /*
- ** This is the case where the Datum PTS is using regular time of day for its
- ** time so we must compute the time zone offset. The way we do it is kind of
- ** funny but it works. We loop through different time zones (0 to 24) and
- ** pick the one that gives the smallest error (+- one half hour). The time
- ** zone offset is stored in the datum_pts structure for future use. Normally,
- ** the clocktime() routine is only called once (unless the time zone offset
- ** changes due to daylight savings) since the goodtime flag is set when a
- ** good time is found (with a good offset). Note that even if the Datum
- ** PTS is using GMT, this mechanism will still work since it should come up
- ** with a value for tzoff = 0 (assuming that your system clock is within
- ** a half hour of the Datum time (even with time zone differences).
- */
- for (tzoff=0; tzoff<24; tzoff++) {
- if (clocktime( datum_pts->day,
- datum_pts->hour,
- datum_pts->minute,
- datum_pts->second,
- (tzoff + datum_pts->tzoff) % 24,
- datum_pts->lastrec.l_ui,
- &datum_pts->yearstart,
- &datum_pts->lastref.l_ui) ) {
- datum_pts->lastref.l_uf = 0;
- error = datum_pts->lastref.l_ui - datum_pts->lastrec.l_ui;
- #ifdef DEBUG_DATUM_PTC
- printf("Time Zone (clocktime method) = %d, error = %d\n", tzoff, error);
- #endif
- if ((error < 1799) && (error > -1799)) {
- tzoff = (tzoff + datum_pts->tzoff) % 24;
- datum_pts->tzoff = tzoff;
- goodtime = 1;
- #ifdef DEBUG_DATUM_PTC
- printf("Time Zone found (clocktime method) = %d\n",tzoff);
- #endif
- break;
- }
- }
- }
- #endif
- /*
- ** Make sure that we have a good time from the Datum PTS. Clocktime() also
- ** sets yearstart and lastref.l_ui. We will have to set astref.l_uf (i.e.,
- ** the fraction of a second) stuff later.
- */
- if (!goodtime) {
- if (!clocktime( datum_pts->day,
- datum_pts->hour,
- datum_pts->minute,
- datum_pts->second,
- tzoff,
- datum_pts->lastrec.l_ui,
- &datum_pts->yearstart,
- &datum_pts->lastref.l_ui) ) {
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- {
- printf("Error: bad clocktime\n");
- printf("GMT %d, lastrec %d, yearstart %d, lastref %d\n",
- tzoff,
- datum_pts->lastrec.l_ui,
- datum_pts->yearstart,
- datum_pts->lastref.l_ui);
- }
- #endif
- msyslog(LOG_ERR, "Datum_PTS: Bad clocktime");
- return;
- }else{
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Good clocktime\n");
- #endif
- }
- }
- /*
- ** We have datum_pts->lastref.l_ui set (which is the integer part of the
- ** time. Now set the microseconds field.
- */
- TVUTOTSF(datum_pts->usec, datum_pts->lastref.l_uf);
- /*
- ** Compute the time correction as the difference between the reference
- ** time (i.e., the Datum time) minus the receive time (system time).
- */
- tstmp = datum_pts->lastref; /* tstmp is the datum ntp time */
- L_SUB(&tstmp, &datum_pts->lastrec); /* tstmp is now the correction */
- datum_pts->coderecv++; /* increment a counter */
- #ifdef DEBUG_DATUM_PTC
- dispersion = DATUM_DISPERSION; /* set the dispersion to 0 */
- ftimerr = dispersion;
- ftimerr /= (1024.0 * 64.0);
- if (debug)
- printf("dispersion = %d, %f\n", dispersion, ftimerr);
- #endif
- /*
- ** Pass the new time to ntpd through the refclock_receive function. Note
- ** that we are not trying to make any corrections due to the time it takes
- ** for the Datum PTS to send the message back. I am (erroneously) assuming
- ** that the time for the Datum PTS to send the time back to us is negligable.
- ** I suspect that this time delay may be as much as 15 ms or so (but probably
- ** less). For our needs at JPL, this kind of error is ok so it is not
- ** necessary to use fudge factors in the ntp.conf file. Maybe later we will.
- */
- /*LFPTOD(&tstmp, doffset);*/
- datum_pts->lastref = datum_pts->lastrec;
- refclock_receive(datum_pts->peer);
- /*
- ** Compute sigma squared (not used currently). Maybe later, this could be
- ** used for the dispersion estimate. The problem is that ntpd does not link
- ** in the math library so sqrt() is not available. Anyway, this is useful
- ** for debugging. Maybe later I will just use absolute values for the time
- ** error to come up with my dispersion estimate. Anyway, for now my dispersion
- ** is set to 0.
- */
- timerr = tstmp.l_ui<<20;
- timerr |= (tstmp.l_uf>>12) & 0x000fffff;
- ftimerr = timerr;
- ftimerr /= 1024*1024;
- abserr = ftimerr;
- if (ftimerr < 0.0) abserr = -ftimerr;
- if (datum_pts->sigma2 == 0.0) {
- if (abserr < DATUM_MAX_ERROR) {
- datum_pts->sigma2 = abserr*abserr;
- }else{
- datum_pts->sigma2 = DATUM_MAX_ERROR2;
- }
- }else{
- if (abserr < DATUM_MAX_ERROR) {
- datum_pts->sigma2 = 0.95*datum_pts->sigma2 + 0.05*abserr*abserr;
- }else{
- datum_pts->sigma2 = 0.95*datum_pts->sigma2 + 0.05*DATUM_MAX_ERROR2;
- }
- }
- #ifdef DEBUG_DATUM_PTC
- if (debug)
- printf("Time error = %f seconds\n", ftimerr);
- #endif
- #if defined(DEBUG_DATUM_PTC) || defined(LOG_TIME_ERRORS)
- if (debug)
- printf("PTS: day %d, hour %d, minute %d, second %d, msec %d, Time Error %f\n",
- datum_pts->day,
- datum_pts->hour,
- datum_pts->minute,
- datum_pts->second,
- datum_pts->msec,
- ftimerr);
- #endif
- }
- #else
- int refclock_datum_bs;
- #endif /* REFCLOCK */