2 * ntpdate.h - declarations for the ntpdate and ntptimeset programs
5 #include "ntp_malloc.h"
7 extern void loadservers P((char *cfgpath));
10 * The server structure is a much simplified version of the
11 * peer structure, for ntpdate's use. Since we always send
12 * in client mode and expect to receive in server mode, this
13 * leaves only a very limited number of things we need to
14 * remember about the server.
17 struct server *next_server; /* next server in build list */
18 struct sockaddr_storage srcadr; /* address of remote host */
19 u_char version; /* version to use */
20 u_char leap; /* leap indicator */
21 u_char stratum; /* stratum of remote server */
22 s_char precision; /* server's clock precision */
23 u_char trust; /* trustability of the filtered data */
24 u_fp rootdelay; /* distance from primary clock */
25 u_fp rootdispersion; /* peer clock dispersion */
26 u_int32 refid; /* peer reference ID */
27 l_fp reftime; /* time of peer's last update */
28 u_long event_time; /* time for next timeout */
29 u_long last_xmit; /* time of last transmit */
30 u_short xmtcnt; /* number of packets transmitted */
31 u_short rcvcnt; /* number of packets received */
32 u_char reach; /* reachability, NTP_WINDOW bits */
33 u_short filter_nextpt; /* index into filter shift register */
34 s_fp filter_delay[NTP_SHIFT]; /* delay part of shift register */
35 l_fp filter_offset[NTP_SHIFT]; /* offset part of shift register */
36 s_fp filter_soffset[NTP_SHIFT]; /* offset in s_fp format, for disp */
37 u_fp filter_error[NTP_SHIFT]; /* error part of shift register */
38 l_fp org; /* peer's originate time stamp */
39 l_fp xmt; /* transmit time stamp */
40 u_fp delay; /* filter estimated delay */
41 u_fp dispersion; /* filter estimated dispersion */
42 l_fp offset; /* filter estimated clock offset */
43 s_fp soffset; /* fp version of above */
48 * ntpdate runs everything on a simple, short timeout. It sends a
49 * packet and sets the timeout (by default, to a small value suitable
50 * for a LAN). If it receives a response it sends another request.
51 * If it times out it shifts zeroes into the filter and sends another
54 * The timer routine is run often (once every 1/5 second currently)
55 * so that time outs are done with reasonable precision.
57 #define TIMER_HZ (5) /* 5 per second */
60 * ntpdate will make a long adjustment using adjtime() if the times
61 * are close, or step the time if the times are farther apart. The
62 * following defines what is "close".
64 #define NTPDATE_THRESHOLD (FP_SECOND >> 1) /* 1/2 second */
66 #define NTP_MAXAGE 86400 /* one day in seconds */
69 * When doing adjustments, ntpdate actually overadjusts (currently
70 * by 50%, though this may change). While this will make it take longer
71 * to reach a steady state condition, it will typically result in
72 * the clock keeping more accurate time, on average. The amount of
73 * overshoot is limited.
76 #define ADJ_OVERSHOOT 1/2 /* this is hard coded */
78 #define ADJ_MAXOVERSHOOT 0x10000000 /* 50 ms as a ts fraction */
81 * Since ntpdate isn't aware of some of the things that normally get
82 * put in an NTP packet, we fix some values.
84 #define NTPDATE_PRECISION (-6) /* use this precision */
85 #define NTPDATE_DISTANCE FP_SECOND /* distance is 1 sec */
86 #define NTPDATE_DISP FP_SECOND /* so is the dispersion */
87 #define NTPDATE_REFID (0) /* reference ID to use */
88 #define PEER_MAXDISP (64*FP_SECOND) /* maximum dispersion (fp 64) */
94 #define DEFTIMEOUT 5 /* 5 timer increments */
95 #define DEFSAMPLES 4 /* get 4 samples per server */
96 #define DEFPRECISION (-5) /* the precision we claim */
97 #define DEFMAXPERIOD 60 /* maximum time to wait */
98 #define DEFMINSERVERS 3 /* minimum responding servers */
99 #define DEFMINVALID 1 /* mimimum servers with valid time */
102 * Define the max number of sockets we can open