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