90 lines
3.2 KiB
C
90 lines
3.2 KiB
C
/*
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* ntpdate.h - declarations for the ntpdate program
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*/
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#include "ntp_malloc.h"
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/*
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* The server structure is a much simplified version of the
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* peer structure, for ntpdate's use. Since we always send
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* in client mode and expect to receive in server mode, this
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* leaves only a very limited number of things we need to
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* remember about the server.
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*/
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struct server {
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struct sockaddr_in srcadr; /* address of remote host */
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u_char leap; /* leap indicator */
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u_char stratum; /* stratum of remote server */
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s_char precision; /* server's clock precision */
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u_char trust; /* trustability of the filtered data */
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u_fp rootdelay; /* distance from primary clock */
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u_fp rootdispersion; /* peer clock dispersion */
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U_LONG refid; /* peer reference ID */
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l_fp reftime; /* time of peer's last update */
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u_long event_time; /* time for next timeout */
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u_short xmtcnt; /* number of packets transmitted */
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u_short filter_nextpt; /* index into filter shift register */
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s_fp filter_delay[NTP_SHIFT]; /* delay part of shift register */
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l_fp filter_offset[NTP_SHIFT]; /* offset part of shift register */
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s_fp filter_soffset[NTP_SHIFT]; /* offset in s_fp format, for disp */
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u_fp filter_error[NTP_SHIFT]; /* error part of shift register */
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l_fp org; /* peer's originate time stamp */
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l_fp xmt; /* transmit time stamp */
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u_fp delay; /* filter estimated delay */
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u_fp dispersion; /* filter estimated dispersion */
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l_fp offset; /* filter estimated clock offset */
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s_fp soffset; /* fp version of above */
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};
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/*
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* ntpdate runs everything on a simple, short timeout. It sends a
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* packet and sets the timeout (by default, to a small value suitable
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* for a LAN). If it receives a response it sends another request.
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* If it times out it shifts zeroes into the filter and sends another
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* request.
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*
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* The timer routine is run often (once every 1/5 second currently)
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* so that time outs are done with reasonable precision.
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*/
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#define TIMER_HZ (5) /* 5 per second */
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/*
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* ntpdate will make a long adjustment using adjtime() if the times
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* are close, or step the time if the times are farther apart. The
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* following defines what is "close".
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*/
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#ifdef linux
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#define NTPDATE_THRESHOLD (FP_SECOND / 8) /* 1/8 second */
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#else
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#define NTPDATE_THRESHOLD (FP_SECOND >> 1) /* 1/2 second */
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#endif
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/*
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* When doing adjustments, ntpdate actually overadjusts (currently
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* by 50%, though this may change). While this will make it take longer
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* to reach a steady state condition, it will typically result in
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* the clock keeping more accurate time, on average. The amount of
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* overshoot is limited.
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*/
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#ifdef NOTNOW
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#define ADJ_OVERSHOOT 1/2 /* this is hard coded */
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#endif /* NOTNOW */
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#define ADJ_MAXOVERSHOOT 0x10000000 /* 50 ms as a ts fraction */
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/*
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* Since ntpdate isn't aware of some of the things that normally get
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* put in an NTP packet, we fix some values.
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*/
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#define NTPDATE_PRECISION (-6) /* use this precision */
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#define NTPDATE_DISTANCE FP_SECOND /* distance is 1 sec */
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#define NTPDATE_DISP FP_SECOND /* so is the dispersion */
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#define NTPDATE_REFID (0) /* reference ID to use */
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/*
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* Some defaults
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*/
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#define DEFTIMEOUT 5 /* 5 timer increments */
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#define DEFSAMPLES 4 /* get 4 samples per server */
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