usr.sbin/dntpd/client.h

   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