2 * ntpdate.h - declarations for the ntpdate and ntptimeset programs
5 #include "ntp_malloc.h"
8 * The server structure is a much simplified version of the
9 * peer structure, for ntpdate's use. Since we always send
10 * in client mode and expect to receive in server mode, this
11 * leaves only a very limited number of things we need to
12 * remember about the server.
15 struct server *next_server; /* next server in build list */
16 struct sockaddr_in srcadr; /* address of remote host */
17 u_char version; /* version to use */
18 u_char leap; /* leap indicator */
19 u_char stratum; /* stratum of remote server */
20 s_char precision; /* server's clock precision */
21 u_char trust; /* trustability of the filtered data */
22 u_fp rootdelay; /* distance from primary clock */
23 u_fp rootdispersion; /* peer clock dispersion */
24 u_int32 refid; /* peer reference ID */
25 l_fp reftime; /* time of peer's last update */
26 u_long event_time; /* time for next timeout */
27 u_long last_xmit; /* time of last transmit */
28 u_short xmtcnt; /* number of packets transmitted */
29 u_short rcvcnt; /* number of packets received */
30 u_char reach; /* reachability, NTP_WINDOW bits */
31 u_short filter_nextpt; /* index into filter shift register */
32 s_fp filter_delay[NTP_SHIFT]; /* delay part of shift register */
33 l_fp filter_offset[NTP_SHIFT]; /* offset part of shift register */
34 s_fp filter_soffset[NTP_SHIFT]; /* offset in s_fp format, for disp */
35 u_fp filter_error[NTP_SHIFT]; /* error part of shift register */
36 l_fp org; /* peer's originate time stamp */
37 l_fp xmt; /* transmit time stamp */
38 u_fp delay; /* filter estimated delay */
39 u_fp dispersion; /* filter estimated dispersion */
40 l_fp offset; /* filter estimated clock offset */
41 s_fp soffset; /* fp version of above */
46 * ntpdate runs everything on a simple, short timeout. It sends a
47 * packet and sets the timeout (by default, to a small value suitable
48 * for a LAN). If it receives a response it sends another request.
49 * If it times out it shifts zeroes into the filter and sends another
52 * The timer routine is run often (once every 1/5 second currently)
53 * so that time outs are done with reasonable precision.
55 #define TIMER_HZ (5) /* 5 per second */
58 * ntpdate will make a long adjustment using adjtime() if the times
59 * are close, or step the time if the times are farther apart. The
60 * following defines what is "close".
62 #define NTPDATE_THRESHOLD (FP_SECOND >> 1) /* 1/2 second */
65 * When doing adjustments, ntpdate actually overadjusts (currently
66 * by 50%, though this may change). While this will make it take longer
67 * to reach a steady state condition, it will typically result in
68 * the clock keeping more accurate time, on average. The amount of
69 * overshoot is limited.
72 #define ADJ_OVERSHOOT 1/2 /* this is hard coded */
74 #define ADJ_MAXOVERSHOOT 0x10000000 /* 50 ms as a ts fraction */
77 * Since ntpdate isn't aware of some of the things that normally get
78 * put in an NTP packet, we fix some values.
80 #define NTPDATE_PRECISION (-6) /* use this precision */
81 #define NTPDATE_DISTANCE FP_SECOND /* distance is 1 sec */
82 #define NTPDATE_DISP FP_SECOND /* so is the dispersion */
83 #define NTPDATE_REFID (0) /* reference ID to use */
84 #define PEER_MAXDISP (64*FP_SECOND) /* maximum dispersion (fp 64) */
90 #define DEFTIMEOUT 5 /* 5 timer increments */
91 #define DEFSAMPLES 4 /* get 4 samples per server */
92 #define DEFPRECISION (-5) /* the precision we claim */
93 #define DEFMAXPERIOD 60 /* maximum time to wait */
94 #define DEFMINSERVERS 3 /* minimum responding servers */
95 #define DEFMINVALID 1 /* mimimum servers with valid time */