xref: /dragonfly/usr.sbin/dntpd/client.h (revision fe08e20d)
1 /*
2  * Copyright (c) 2005 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 struct server_info {
36 	int fd;			/* udp descriptor */
37 	int server_state;	/* -1 (no dns), 0 (dns good), or 1 (pkt good) */
38 	int server_insane;	/* insanity check */
39 	int poll_sleep;		/* countdown for poll (in seconds) */
40 	int poll_mode;		/* mode of operation */
41 	int poll_count;		/* number of polls in current mode */
42 	int poll_failed;	/* count of NTP failures */
43 	struct sockaddr *sam; 	/* udp connection info */
44 	struct sockaddr_storage sam_st; 	/* udp connection info (stor) */
45 	char *target;		/* target hostname or IP (string) */
46 	char *ipstr;		/* IP string */
47 
48 	/*
49 	 * A second linear regression playing hopskip with the first.  This
50 	 * is maintained by the check function.
51 	 */
52 	struct server_info *altinfo;
53 
54 	/*
55 	 * Linear regression accumulator
56 	 *
57 	 * note: the starting base time is where all corrections get applied
58 	 * to eventually.  The linear regression makes a relative microseconds
59 	 * calculation between the current base time and the starting base
60 	 * time to figure out what corrections the system has made to the
61 	 * clock.
62 	 */
63 	struct timeval lin_tv;	/* starting real time */
64 	struct timeval lin_btv;	/* starting base time */
65 	double lin_count;	/* samples	*/
66 	double lin_sumx;	/* sum(x)	*/
67 	double lin_sumy;	/* sum(y)	*/
68 	double lin_sumxy;	/* sum(x*y)	*/
69 	double lin_sumx2;	/* sum(x^2) 	*/
70 	double lin_sumy2;	/* sum(y^2) 	*/
71 
72 	/*
73 	 * Offsets are accumulated for a straight average.  When a
74 	 * correction is made we have to reset the averaging code
75 	 * or follow-up corrections will oscillate wildly because
76 	 * the new offsets simply cannot compete with the dozens
77 	 * of previously polls in the sum.
78 	 */
79 	double lin_sumoffset;	/* sum of compensated offsets */
80 	double lin_sumoffset2;	/* sum of compensated offsets^2 */
81 	double lin_countoffset;	/* count is reset after a correction is made */
82 
83 	/*
84 	 * Cached results
85 	 */
86 	double lin_cache_slope;	/* (freq calculations) */
87 	double lin_cache_yint;	/* (freq calculations) */
88 	double lin_cache_corr;	/* (freq calculations) */
89 	double lin_cache_stddev; /* (offset calculations) */
90 
91 	double lin_cache_offset; /* last sampled offset (NOT an average) */
92 	double lin_cache_freq;	/* last frequency correction (s/s) */
93 };
94 
95 /*
96  * Polling modes and max polls for specific modes.  Note that the polling
97  * mode basically just effects the polling rate.  It does not effect the
98  * linear regression.
99  */
100 #define POLL_FIXED	0	/* fixed internal (nom_sleep_opt seconds) */
101 #define POLL_STARTUP	1	/* startup poll for offset adjust (min) */
102 #define POLL_ACQUIRE	2	/* acquisition for frequency adjust (nom) */
103 #define POLL_MAINTAIN	3	/* maintainance mode (max) */
104 #define POLL_FAILED	4	/* failure state (nom) */
105 
106 #define POLL_STARTUP_MAX	6	/* max polls in this mode */
107 #define POLL_ACQUIRE_MAX	16	/* max polls in this mode */
108 #define POLL_FAIL_RESET		3	/* reset the regression after 3 fails */
109 #define POLL_RECOVERY_RESTART	10	/* ->ACQ vs ->STARTUP after recovery */
110 
111 /*
112  * We start a second linear regression a LIN_RESTART / 2 and it
113  * replaces the first one (and we start a third) at LIN_RESTART.
114  */
115 #define LIN_RESTART	30
116 
117 /*
118  * A course correction is made if the time gets more then 2 minutes
119  * off.
120  */
121 #define COURSE_OFFSET_CORRECTION_LIMIT	120.0
122 
123 typedef struct server_info *server_info_t;
124 
125 void client_init(void);
126 void client_main(struct server_info **info_ary, int count) __dead2;
127 void client_poll(server_info_t info, int poll_interval,
128 		  int calc_offset_correction);
129 void client_check(struct server_info **check,
130 		  struct server_info **best_off,
131 		  struct server_info **best_freq);
132 void client_check_duplicate_ips(struct server_info **info_ary, int count);
133 void client_manage_polling_mode(struct server_info *info, int *didreconnect);
134 void client_setserverstate(server_info_t info, int state, const char *str);
135 
136 void lin_regress(server_info_t info,
137 		 struct timeval *ltv, struct timeval *lbtv,
138 		 double offset, int calc_offset_correction);
139 void lin_reset(server_info_t info);
140 void lin_resetalloffsets(struct server_info **info_ary, int count);
141 void lin_resetoffsets(server_info_t info);
142 
143