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  * $DragonFly: src/usr.sbin/dntpd/client.h,v 1.7 2007/06/25 21:33:36 dillon Exp $
  35  */
  36
  37 struct server_info {
  38         int fd;                 /* udp descriptor */
  39         int server_state;       /* -1 (no dns), 0 (dns good), or 1 (pkt good) */
  40         int server_insane;      /* insanity check */
  41         int poll_sleep;         /* countdown for poll (in seconds) */
  42         int poll_mode;          /* mode of operation */
  43         int poll_count;         /* number of polls in current mode */
  44         int poll_failed;        /* count of NTP failures */
  45         struct sockaddr *sam;   /* udp connection info */
  46         struct sockaddr_storage sam_st;         /* udp connection info (stor) */
  47         char *target;           /* target hostname or IP (string) */
  48         char *ipstr;            /* IP string */
  49
  50         /*
  51          * A second linear regression playing hopskip with the first.  This
  52          * is maintained by the check function.
  53          */
  54         struct server_info *altinfo;
  55
  56         /*
  57          * Linear regression accumulator
  58          *
  59          * note: the starting base time is where all corrections get applied
  60          * to eventually.  The linear regression makes a relative microseconds
  61          * calculation between the current base time and the starting base
  62          * time to figure out what corrections the system has made to the
  63          * clock.
  64          */
  65         struct timeval lin_tv;  /* starting real time */
  66         struct timeval lin_btv; /* starting base time */
  67         double lin_count;       /* samples      */
  68         double lin_sumx;        /* sum(x)       */
  69         double lin_sumy;        /* sum(y)       */
  70         double lin_sumxy;       /* sum(x*y)     */
  71         double lin_sumx2;       /* sum(x^2)     */
  72         double lin_sumy2;       /* sum(y^2)     */
  73
  74         /*
  75          * Offsets are accumulated for a straight average.  When a
  76          * correction is made we have to reset the averaging code
  77          * or follow-up corrections will oscillate wildly because
  78          * the new offsets simply cannot compete with the dozens
  79          * of previously polls in the sum.
  80          */
  81         double lin_sumoffset;   /* sum of compensated offsets */
  82         double lin_sumoffset2;  /* sum of compensated offsets^2 */
  83         double lin_countoffset; /* count is reset after a correction is made */
  84
  85         /*
  86          * Cached results
  87          */
  88         double lin_cache_slope; /* (freq calculations) */
  89         double lin_cache_yint;  /* (freq calculations) */
  90         double lin_cache_corr;  /* (freq calculations) */
  91         double lin_cache_stddev; /* (offset calculations) */
  92
  93         double lin_cache_offset; /* last sampled offset (NOT an average) */
  94         double lin_cache_freq;  /* last frequency correction (s/s) */
  95 };
  96
  97 /*
  98  * Polling modes and max polls for specific modes.  Note that the polling
  99  * mode basically just effects the polling rate.  It does not effect the
 100  * linear regression.
 101  */
 102 #define POLL_FIXED      0       /* fixed internal (nom_sleep_opt seconds) */
 103 #define POLL_STARTUP    1       /* startup poll for offset adjust (min) */
 104 #define POLL_ACQUIRE    2       /* acquisition for frequency adjust (nom) */
 105 #define POLL_MAINTAIN   3       /* maintainance mode (max) */
 106 #define POLL_FAILED     4       /* failure state (nom) */
 107
 108 #define POLL_STARTUP_MAX        6       /* max polls in this mode */
 109 #define POLL_ACQUIRE_MAX        16      /* max polls in this mode */
 110 #define POLL_FAIL_RESET         3       /* reset the regression after 3 fails */
 111 #define POLL_RECOVERY_RESTART   10      /* ->ACQ vs ->STARTUP after recovery */
 112
 113 /*
 114  * We start a second linear regression a LIN_RESTART / 2 and it
 115  * replaces the first one (and we start a third) at LIN_RESTART.
 116  */
 117 #define LIN_RESTART     30
 118
 119 /*
 120  * A course correction is made if the time gets more then 2 minutes
 121  * off.
 122  */
 123 #define COURSE_OFFSET_CORRECTION_LIMIT  120.0
 124
 125 typedef struct server_info *server_info_t;
 126
 127 void client_init(void);
 128 int client_main(struct server_info **info_ary, int count);
 129 void client_poll(server_info_t info, int poll_interval,
 130                   int calc_offset_correction);
 131 void client_check(struct server_info **check,
 132                   struct server_info **best_off,
 133                   struct server_info **best_freq);
 134 void client_check_duplicate_ips(struct server_info **info_ary, int count);
 135 void client_manage_polling_mode(struct server_info *info, int *didreconnect);
 136 void client_setserverstate(server_info_t info, int state, const char *str);
 137
 138 void lin_regress(server_info_t info,
 139                  struct timeval *ltv, struct timeval *lbtv,
 140                  double offset, int calc_offset_correction);
 141 void lin_reset(server_info_t info);
 142 void lin_resetalloffsets(struct server_info **info_ary, int count);
 143 void lin_resetoffsets(server_info_t info);
 144