2010 lines
63 KiB
C
2010 lines
63 KiB
C
/*
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* NTP client/server, based on OpenNTPD 3.9p1
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*
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* Author: Adam Tkac <vonsch@gmail.com>
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*
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* Licensed under GPLv2, see file LICENSE in this tarball for details.
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*
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* Parts of OpenNTPD clock syncronization code is replaced by
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* code which is based on ntp-4.2.6, whuch carries the following
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* copyright notice:
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*
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***********************************************************************
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* *
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* Copyright (c) University of Delaware 1992-2009 *
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* *
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* Permission to use, copy, modify, and distribute this software and *
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* its documentation for any purpose with or without fee is hereby *
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* granted, provided that the above copyright notice appears in all *
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* copies and that both the copyright notice and this permission *
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* notice appear in supporting documentation, and that the name *
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* University of Delaware not be used in advertising or publicity *
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* pertaining to distribution of the software without specific, *
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* written prior permission. The University of Delaware makes no *
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* representations about the suitability this software for any *
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* purpose. It is provided "as is" without express or implied *
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* warranty. *
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* *
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***********************************************************************
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*/
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#include "libbb.h"
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#include <math.h>
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#include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
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#include <sys/timex.h>
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#ifndef IPTOS_LOWDELAY
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# define IPTOS_LOWDELAY 0x10
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#endif
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#ifndef IP_PKTINFO
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# error "Sorry, your kernel has to support IP_PKTINFO"
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#endif
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/* Verbosity control (max level of -dddd options accepted).
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* max 5 is very talkative (and bloated). 2 is non-bloated,
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* production level setting.
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*/
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#define MAX_VERBOSE 2
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#define RETRY_INTERVAL 5 /* on error, retry in N secs */
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#define QUERYTIME_MAX 15 /* wait for reply up to N secs */
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#define FREQ_TOLERANCE 0.000015 /* % frequency tolerance (15 PPM) */
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#define MINPOLL 4 /* % minimum poll interval (6: 64 s) */
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#define MAXPOLL 12 /* % maximum poll interval (12: 1.1h, 17: 36.4h) (was 17) */
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#define MINDISP 0.01 /* % minimum dispersion (s) */
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#define MAXDISP 16 /* maximum dispersion (s) */
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#define MAXSTRAT 16 /* maximum stratum (infinity metric) */
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#define MAXDIST 1 /* % distance threshold (s) */
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#define MIN_SELECTED 1 /* % minimum intersection survivors */
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#define MIN_CLUSTERED 3 /* % minimum cluster survivors */
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#define MAXDRIFT 0.000500 /* frequency drift we can correct (500 PPM) */
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/* Clock discipline parameters and constants */
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#define STEP_THRESHOLD 0.128 /* step threshold (s) */
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#define WATCH_THRESHOLD 150 /* stepout threshold (s). std ntpd uses 900 (11 mins (!)) */
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/* NB: set WATCH_THRESHOLD to ~60 when debugging to save time) */
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#define PANIC_THRESHOLD 1000 /* panic threshold (s) */
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/* Poll-adjust threshold.
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* When we see that offset is small enough compared to discipline jitter,
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* we grow a counter: += MINPOLL. When it goes over POLLADJ_LIMIT,
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* we poll_exp++. If offset isn't small, counter -= poll_exp*2,
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* and when it goes below -POLLADJ_LIMIT, we poll_exp--
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*/
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#define POLLADJ_LIMIT 30
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/* If offset < POLLADJ_GATE * discipline_jitter, then we can increase
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* poll interval (we think we can't improve timekeeping
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* by staying at smaller poll).
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*/
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#define POLLADJ_GATE 4
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/* Compromise Allan intercept (s). doc uses 1500, std ntpd uses 512 */
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#define ALLAN 512
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/* PLL loop gain */
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#define PLL 65536
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/* FLL loop gain [why it depends on MAXPOLL??] */
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#define FLL (MAXPOLL + 1)
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/* Parameter averaging constant */
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#define AVG 4
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enum {
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NTP_VERSION = 4,
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NTP_MAXSTRATUM = 15,
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NTP_DIGESTSIZE = 16,
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NTP_MSGSIZE_NOAUTH = 48,
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NTP_MSGSIZE = (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE),
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/* Status Masks */
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MODE_MASK = (7 << 0),
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VERSION_MASK = (7 << 3),
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VERSION_SHIFT = 3,
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LI_MASK = (3 << 6),
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/* Leap Second Codes (high order two bits of m_status) */
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LI_NOWARNING = (0 << 6), /* no warning */
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LI_PLUSSEC = (1 << 6), /* add a second (61 seconds) */
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LI_MINUSSEC = (2 << 6), /* minus a second (59 seconds) */
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LI_ALARM = (3 << 6), /* alarm condition */
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/* Mode values */
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MODE_RES0 = 0, /* reserved */
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MODE_SYM_ACT = 1, /* symmetric active */
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MODE_SYM_PAS = 2, /* symmetric passive */
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MODE_CLIENT = 3, /* client */
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MODE_SERVER = 4, /* server */
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MODE_BROADCAST = 5, /* broadcast */
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MODE_RES1 = 6, /* reserved for NTP control message */
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MODE_RES2 = 7, /* reserved for private use */
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};
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//TODO: better base selection
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#define OFFSET_1900_1970 2208988800UL /* 1970 - 1900 in seconds */
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#define NUM_DATAPOINTS 8
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typedef struct {
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uint32_t int_partl;
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uint32_t fractionl;
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} l_fixedpt_t;
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typedef struct {
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uint16_t int_parts;
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uint16_t fractions;
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} s_fixedpt_t;
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typedef struct {
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uint8_t m_status; /* status of local clock and leap info */
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uint8_t m_stratum;
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uint8_t m_ppoll; /* poll value */
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int8_t m_precision_exp;
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s_fixedpt_t m_rootdelay;
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s_fixedpt_t m_rootdisp;
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uint32_t m_refid;
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l_fixedpt_t m_reftime;
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l_fixedpt_t m_orgtime;
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l_fixedpt_t m_rectime;
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l_fixedpt_t m_xmttime;
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uint32_t m_keyid;
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uint8_t m_digest[NTP_DIGESTSIZE];
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} msg_t;
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typedef struct {
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double d_recv_time;
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double d_offset;
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double d_dispersion;
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} datapoint_t;
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typedef struct {
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len_and_sockaddr *p_lsa;
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char *p_dotted;
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/* when to send new query (if p_fd == -1)
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* or when receive times out (if p_fd >= 0): */
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time_t next_action_time;
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int p_fd;
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int datapoint_idx;
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uint32_t lastpkt_refid;
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uint8_t lastpkt_leap;
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uint8_t lastpkt_stratum;
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uint8_t p_reachable_bits;
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double p_xmttime;
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double lastpkt_recv_time;
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double lastpkt_delay;
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double lastpkt_rootdelay;
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double lastpkt_rootdisp;
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/* produced by filter algorithm: */
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double filter_offset;
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double filter_dispersion;
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double filter_jitter;
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datapoint_t filter_datapoint[NUM_DATAPOINTS];
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/* last sent packet: */
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msg_t p_xmt_msg;
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} peer_t;
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enum {
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OPT_n = (1 << 0),
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OPT_q = (1 << 1),
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OPT_N = (1 << 2),
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OPT_x = (1 << 3),
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/* Insert new options above this line. */
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/* Non-compat options: */
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OPT_p = (1 << 4),
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OPT_l = (1 << 5) * ENABLE_FEATURE_NTPD_SERVER,
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};
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struct globals {
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/* total round trip delay to currently selected reference clock */
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double rootdelay;
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/* reference timestamp: time when the system clock was last set or corrected */
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double reftime;
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/* total dispersion to currently selected reference clock */
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double rootdisp;
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llist_t *ntp_peers;
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#if ENABLE_FEATURE_NTPD_SERVER
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int listen_fd;
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#endif
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unsigned verbose;
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unsigned peer_cnt;
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/* refid: 32-bit code identifying the particular server or reference clock
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* in stratum 0 packets this is a four-character ASCII string,
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* called the kiss code, used for debugging and monitoring
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* in stratum 1 packets this is a four-character ASCII string
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* assigned to the reference clock by IANA. Example: "GPS "
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* in stratum 2+ packets, it's IPv4 address or 4 first bytes of MD5 hash of IPv6
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*/
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uint32_t refid;
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uint8_t leap;
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/* precision is defined as the larger of the resolution and time to
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* read the clock, in log2 units. For instance, the precision of a
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* mains-frequency clock incrementing at 60 Hz is 16 ms, even when the
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* system clock hardware representation is to the nanosecond.
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*
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* Delays, jitters of various kinds are clamper down to precision.
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*
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* If precision_sec is too large, discipline_jitter gets clamped to it
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* and if offset is much smaller than discipline_jitter, poll interval
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* grows even though we really can benefit from staying at smaller one,
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* collecting non-lagged datapoits and correcting the offset.
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* (Lagged datapoits exist when poll_exp is large but we still have
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* systematic offset error - the time distance between datapoints
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* is significat and older datapoints have smaller offsets.
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* This makes our offset estimation a bit smaller than reality)
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* Due to this effect, setting G_precision_sec close to
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* STEP_THRESHOLD isn't such a good idea - offsets may grow
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* too big and we will step. I observed it with -6.
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*
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* OTOH, setting precision too small would result in futile attempts
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* to syncronize to the unachievable precision.
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*
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* -6 is 1/64 sec, -7 is 1/128 sec and so on.
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*/
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#define G_precision_exp -8
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#define G_precision_sec (1.0 / (1 << (- G_precision_exp)))
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uint8_t stratum;
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/* Bool. After set to 1, never goes back to 0: */
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//TODO: fix logic:
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// uint8_t time_was_stepped;
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uint8_t adjtimex_was_done;
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uint8_t discipline_state; // doc calls it c.state
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uint8_t poll_exp; // s.poll
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int polladj_count; // c.count
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long kernel_freq_drift;
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double last_update_offset; // c.last
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double last_update_recv_time; // s.t
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double discipline_jitter; // c.jitter
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//TODO: add s.jitter - grep for it here and see clock_combine() in doc
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#define USING_KERNEL_PLL_LOOP 1
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#if !USING_KERNEL_PLL_LOOP
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double discipline_freq_drift; // c.freq
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//TODO: conditionally calculate wander? it's used only for logging
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double discipline_wander; // c.wander
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#endif
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};
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#define G (*ptr_to_globals)
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static const int const_IPTOS_LOWDELAY = IPTOS_LOWDELAY;
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#define VERB1 if (MAX_VERBOSE && G.verbose)
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#define VERB2 if (MAX_VERBOSE >= 2 && G.verbose >= 2)
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#define VERB3 if (MAX_VERBOSE >= 3 && G.verbose >= 3)
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#define VERB4 if (MAX_VERBOSE >= 4 && G.verbose >= 4)
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#define VERB5 if (MAX_VERBOSE >= 5 && G.verbose >= 5)
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static double LOG2D(int a)
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{
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if (a < 0)
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return 1.0 / (1UL << -a);
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return 1UL << a;
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}
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static ALWAYS_INLINE double SQUARE(double x)
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{
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return x * x;
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}
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static ALWAYS_INLINE double MAXD(double a, double b)
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{
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if (a > b)
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return a;
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return b;
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}
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static ALWAYS_INLINE double MIND(double a, double b)
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{
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if (a < b)
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return a;
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return b;
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}
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#define SQRT(x) (sqrt(x))
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static double
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gettime1900d(void)
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{
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struct timeval tv;
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gettimeofday(&tv, NULL); /* never fails */
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return (tv.tv_sec + 1.0e-6 * tv.tv_usec + OFFSET_1900_1970);
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}
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static void
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d_to_tv(double d, struct timeval *tv)
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{
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tv->tv_sec = (long)d;
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tv->tv_usec = (d - tv->tv_sec) * 1000000;
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}
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static double
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lfp_to_d(l_fixedpt_t lfp)
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{
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double ret;
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lfp.int_partl = ntohl(lfp.int_partl);
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lfp.fractionl = ntohl(lfp.fractionl);
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ret = (double)lfp.int_partl + ((double)lfp.fractionl / UINT_MAX);
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return ret;
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}
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static double
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sfp_to_d(s_fixedpt_t sfp)
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{
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double ret;
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sfp.int_parts = ntohs(sfp.int_parts);
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sfp.fractions = ntohs(sfp.fractions);
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ret = (double)sfp.int_parts + ((double)sfp.fractions / USHRT_MAX);
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return ret;
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}
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#if ENABLE_FEATURE_NTPD_SERVER
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static l_fixedpt_t
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d_to_lfp(double d)
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{
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l_fixedpt_t lfp;
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lfp.int_partl = (uint32_t)d;
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lfp.fractionl = (uint32_t)((d - lfp.int_partl) * UINT_MAX);
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lfp.int_partl = htonl(lfp.int_partl);
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lfp.fractionl = htonl(lfp.fractionl);
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return lfp;
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}
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static s_fixedpt_t
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d_to_sfp(double d)
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{
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s_fixedpt_t sfp;
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sfp.int_parts = (uint16_t)d;
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sfp.fractions = (uint16_t)((d - sfp.int_parts) * USHRT_MAX);
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sfp.int_parts = htons(sfp.int_parts);
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sfp.fractions = htons(sfp.fractions);
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return sfp;
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}
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#endif
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static double
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dispersion(const datapoint_t *dp, double t)
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{
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return dp->d_dispersion + FREQ_TOLERANCE * (t - dp->d_recv_time);
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}
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static double
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root_distance(peer_t *p, double t)
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{
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/* The root synchronization distance is the maximum error due to
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* all causes of the local clock relative to the primary server.
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* It is defined as half the total delay plus total dispersion
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* plus peer jitter.
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*/
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return MAXD(MINDISP, p->lastpkt_rootdelay + p->lastpkt_delay) / 2
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+ p->lastpkt_rootdisp
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+ p->filter_dispersion
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+ FREQ_TOLERANCE * (t - p->lastpkt_recv_time)
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+ p->filter_jitter;
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}
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static void
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set_next(peer_t *p, unsigned t)
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{
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p->next_action_time = time(NULL) + t;
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}
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/*
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* Peer clock filter and its helpers
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*/
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static void
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filter_datapoints(peer_t *p, double t)
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{
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int i, idx;
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double minoff, maxoff, wavg, sum, w;
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double x = x;
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minoff = maxoff = p->filter_datapoint[0].d_offset;
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for (i = 1; i < NUM_DATAPOINTS; i++) {
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if (minoff > p->filter_datapoint[i].d_offset)
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minoff = p->filter_datapoint[i].d_offset;
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if (maxoff < p->filter_datapoint[i].d_offset)
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maxoff = p->filter_datapoint[i].d_offset;
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}
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idx = p->datapoint_idx; /* most recent datapoint */
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/* Average offset:
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* Drop two outliers and take weighted average of the rest:
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* most_recent/2 + older1/4 + older2/8 ... + older5/32 + older6/32
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* we use older6/32, not older6/64 since sum of weights should be 1:
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* 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/32 = 1
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*/
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wavg = 0;
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w = 0.5;
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// n-1
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// --- dispersion(i)
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// filter_dispersion = \ -------------
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// / (i+1)
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// --- 2
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// i=0
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sum = 0;
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for (i = 0; i < NUM_DATAPOINTS; i++) {
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VERB4 {
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bb_error_msg("datapoint[%d]: off:%f disp:%f(%f) age:%f%s",
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i,
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p->filter_datapoint[idx].d_offset,
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p->filter_datapoint[idx].d_dispersion, dispersion(&p->filter_datapoint[idx], t),
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t - p->filter_datapoint[idx].d_recv_time,
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(minoff == p->filter_datapoint[idx].d_offset || maxoff == p->filter_datapoint[idx].d_offset)
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? " (outlier by offset)" : ""
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);
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}
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sum += dispersion(&p->filter_datapoint[idx], t) / (2 << i);
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if (minoff == p->filter_datapoint[idx].d_offset) {
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minoff -= 1; /* so that we don't match it ever again */
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} else
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if (maxoff == p->filter_datapoint[idx].d_offset) {
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maxoff += 1;
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} else {
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x = p->filter_datapoint[idx].d_offset * w;
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wavg += x;
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w /= 2;
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}
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idx = (idx - 1) & (NUM_DATAPOINTS - 1);
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}
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wavg += x; /* add another older6/64 to form older6/32 */
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p->filter_offset = wavg;
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p->filter_dispersion = sum;
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//TODO: fix systematic underestimation with large poll intervals.
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// Imagine that we still have a bit of uncorrected drift,
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// and poll interval is big. Offsets form a progression:
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// 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7, 0.7 is most recent.
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// The algorithm above drops 0.0 and 0.7 as outliers,
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// and then we have this estimation, ~25% off from 0.7:
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// 0.1/32 + 0.2/32 + 0.3/16 + 0.4/8 + 0.5/4 + 0.6/2 = 0.503125
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// +----- -----+ ^ 1/2
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// | n-1 |
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// | --- |
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// 1 | \ 2 |
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// filter_jitter = --- * | / (avg-offset_j) |
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// n | --- |
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// | j=0 |
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// +----- -----+
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// where n is the number of valid datapoints in the filter (n > 1);
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// if filter_jitter < precision then filter_jitter = precision
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sum = 0;
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for (i = 0; i < NUM_DATAPOINTS; i++) {
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sum += SQUARE(wavg - p->filter_datapoint[i].d_offset);
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}
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sum = SQRT(sum) / NUM_DATAPOINTS;
|
|
p->filter_jitter = sum > G_precision_sec ? sum : G_precision_sec;
|
|
|
|
VERB3 bb_error_msg("filter offset:%f disp:%f jitter:%f",
|
|
p->filter_offset, p->filter_dispersion, p->filter_jitter);
|
|
|
|
}
|
|
|
|
static void
|
|
reset_peer_stats(peer_t *p, double t, double offset)
|
|
{
|
|
int i;
|
|
for (i = 0; i < NUM_DATAPOINTS; i++) {
|
|
if (offset < 16 * STEP_THRESHOLD) {
|
|
p->filter_datapoint[i].d_recv_time -= offset;
|
|
if (p->filter_datapoint[i].d_offset != 0) {
|
|
p->filter_datapoint[i].d_offset -= offset;
|
|
}
|
|
} else {
|
|
p->filter_datapoint[i].d_recv_time = t;
|
|
p->filter_datapoint[i].d_offset = 0;
|
|
p->filter_datapoint[i].d_dispersion = MAXDISP;
|
|
}
|
|
}
|
|
if (offset < 16 * STEP_THRESHOLD) {
|
|
p->lastpkt_recv_time -= offset;
|
|
} else {
|
|
p->p_reachable_bits = 0;
|
|
p->lastpkt_recv_time = t;
|
|
}
|
|
filter_datapoints(p, t); /* recalc p->filter_xxx */
|
|
p->next_action_time -= (time_t)offset;
|
|
VERB5 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
|
|
}
|
|
|
|
static void
|
|
add_peers(char *s)
|
|
{
|
|
peer_t *p;
|
|
|
|
p = xzalloc(sizeof(*p));
|
|
p->p_lsa = xhost2sockaddr(s, 123);
|
|
p->p_dotted = xmalloc_sockaddr2dotted_noport(&p->p_lsa->u.sa);
|
|
p->p_fd = -1;
|
|
p->p_xmt_msg.m_status = MODE_CLIENT | (NTP_VERSION << 3);
|
|
p->next_action_time = time(NULL); /* = set_next(p, 0); */
|
|
reset_peer_stats(p, gettime1900d(), 16 * STEP_THRESHOLD);
|
|
/* Speed up initial sync: with small offsets from peers,
|
|
* 3 samples will sync
|
|
*/
|
|
p->filter_datapoint[6].d_dispersion = 0;
|
|
p->filter_datapoint[7].d_dispersion = 0;
|
|
|
|
llist_add_to(&G.ntp_peers, p);
|
|
G.peer_cnt++;
|
|
}
|
|
|
|
static int
|
|
do_sendto(int fd,
|
|
const struct sockaddr *from, const struct sockaddr *to, socklen_t addrlen,
|
|
msg_t *msg, ssize_t len)
|
|
{
|
|
ssize_t ret;
|
|
|
|
errno = 0;
|
|
if (!from) {
|
|
ret = sendto(fd, msg, len, MSG_DONTWAIT, to, addrlen);
|
|
} else {
|
|
ret = send_to_from(fd, msg, len, MSG_DONTWAIT, to, from, addrlen);
|
|
}
|
|
if (ret != len) {
|
|
bb_perror_msg("send failed");
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
send_query_to_peer(peer_t *p)
|
|
{
|
|
// Why do we need to bind()?
|
|
// See what happens when we don't bind:
|
|
//
|
|
// socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
|
|
// setsockopt(3, SOL_IP, IP_TOS, [16], 4) = 0
|
|
// gettimeofday({1259071266, 327885}, NULL) = 0
|
|
// sendto(3, "xxx", 48, MSG_DONTWAIT, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr("10.34.32.125")}, 16) = 48
|
|
// ^^^ we sent it from some source port picked by kernel.
|
|
// time(NULL) = 1259071266
|
|
// write(2, "ntpd: entering poll 15 secs\n", 28) = 28
|
|
// poll([{fd=3, events=POLLIN}], 1, 15000) = 1 ([{fd=3, revents=POLLIN}])
|
|
// recv(3, "yyy", 68, MSG_DONTWAIT) = 48
|
|
// ^^^ this recv will receive packets to any local port!
|
|
//
|
|
// Uncomment this and use strace to see it in action:
|
|
#define PROBE_LOCAL_ADDR // { len_and_sockaddr lsa; lsa.len = LSA_SIZEOF_SA; getsockname(p->query.fd, &lsa.u.sa, &lsa.len); }
|
|
|
|
if (p->p_fd == -1) {
|
|
int fd, family;
|
|
len_and_sockaddr *local_lsa;
|
|
|
|
family = p->p_lsa->u.sa.sa_family;
|
|
p->p_fd = fd = xsocket_type(&local_lsa, family, SOCK_DGRAM);
|
|
/* local_lsa has "null" address and port 0 now.
|
|
* bind() ensures we have a *particular port* selected by kernel
|
|
* and remembered in p->p_fd, thus later recv(p->p_fd)
|
|
* receives only packets sent to this port.
|
|
*/
|
|
PROBE_LOCAL_ADDR
|
|
xbind(fd, &local_lsa->u.sa, local_lsa->len);
|
|
PROBE_LOCAL_ADDR
|
|
#if ENABLE_FEATURE_IPV6
|
|
if (family == AF_INET)
|
|
#endif
|
|
setsockopt(fd, IPPROTO_IP, IP_TOS, &const_IPTOS_LOWDELAY, sizeof(const_IPTOS_LOWDELAY));
|
|
free(local_lsa);
|
|
}
|
|
|
|
/*
|
|
* Send out a random 64-bit number as our transmit time. The NTP
|
|
* server will copy said number into the originate field on the
|
|
* response that it sends us. This is totally legal per the SNTP spec.
|
|
*
|
|
* The impact of this is two fold: we no longer send out the current
|
|
* system time for the world to see (which may aid an attacker), and
|
|
* it gives us a (not very secure) way of knowing that we're not
|
|
* getting spoofed by an attacker that can't capture our traffic
|
|
* but can spoof packets from the NTP server we're communicating with.
|
|
*
|
|
* Save the real transmit timestamp locally.
|
|
*/
|
|
p->p_xmt_msg.m_xmttime.int_partl = random();
|
|
p->p_xmt_msg.m_xmttime.fractionl = random();
|
|
p->p_xmttime = gettime1900d();
|
|
|
|
if (do_sendto(p->p_fd, /*from:*/ NULL, /*to:*/ &p->p_lsa->u.sa, /*addrlen:*/ p->p_lsa->len,
|
|
&p->p_xmt_msg, NTP_MSGSIZE_NOAUTH) == -1
|
|
) {
|
|
close(p->p_fd);
|
|
p->p_fd = -1;
|
|
set_next(p, RETRY_INTERVAL);
|
|
return -1;
|
|
}
|
|
|
|
p->p_reachable_bits <<= 1;
|
|
VERB1 bb_error_msg("sent query to %s", p->p_dotted);
|
|
set_next(p, QUERYTIME_MAX);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void
|
|
step_time(double offset)
|
|
{
|
|
double dtime;
|
|
struct timeval tv;
|
|
char buf[80];
|
|
time_t tval;
|
|
|
|
gettimeofday(&tv, NULL); /* never fails */
|
|
dtime = offset + tv.tv_sec;
|
|
dtime += 1.0e-6 * tv.tv_usec;
|
|
d_to_tv(dtime, &tv);
|
|
|
|
if (settimeofday(&tv, NULL) == -1)
|
|
bb_perror_msg_and_die("settimeofday");
|
|
|
|
tval = tv.tv_sec;
|
|
strftime(buf, sizeof(buf), "%a %b %e %H:%M:%S %Z %Y", localtime(&tval));
|
|
|
|
bb_error_msg("setting clock to %s (offset %fs)", buf, offset);
|
|
|
|
// G.time_was_stepped = 1;
|
|
}
|
|
|
|
|
|
/*
|
|
* Selection and clustering, and their helpers
|
|
*/
|
|
typedef struct {
|
|
peer_t *p;
|
|
int type;
|
|
double edge;
|
|
} point_t;
|
|
static int
|
|
compare_point_edge(const void *aa, const void *bb)
|
|
{
|
|
const point_t *a = aa;
|
|
const point_t *b = bb;
|
|
if (a->edge < b->edge) {
|
|
return -1;
|
|
}
|
|
return (a->edge > b->edge);
|
|
}
|
|
typedef struct {
|
|
peer_t *p;
|
|
double metric;
|
|
} survivor_t;
|
|
static int
|
|
compare_survivor_metric(const void *aa, const void *bb)
|
|
{
|
|
const survivor_t *a = aa;
|
|
const survivor_t *b = bb;
|
|
if (a->metric < b->metric)
|
|
return -1;
|
|
return (a->metric > b->metric);
|
|
}
|
|
static int
|
|
fit(peer_t *p, double rd)
|
|
{
|
|
if (p->p_reachable_bits == 0) {
|
|
VERB3 bb_error_msg("peer %s unfit for selection: unreachable", p->p_dotted);
|
|
return 0;
|
|
}
|
|
//TODO: we never accept such packets anyway, right?
|
|
if ((p->lastpkt_leap & LI_ALARM) == LI_ALARM
|
|
|| p->lastpkt_stratum >= MAXSTRAT
|
|
) {
|
|
VERB3 bb_error_msg("peer %s unfit for selection: bad status/stratum", p->p_dotted);
|
|
return 0;
|
|
}
|
|
/* rd is root_distance(p, t) */
|
|
if (rd > MAXDIST + FREQ_TOLERANCE * (1 << G.poll_exp)) {
|
|
VERB3 bb_error_msg("peer %s unfit for selection: root distance too high", p->p_dotted);
|
|
return 0;
|
|
}
|
|
//TODO
|
|
// /* Do we have a loop? */
|
|
// if (p->refid == p->dstaddr || p->refid == s.refid)
|
|
// return 0;
|
|
return 1;
|
|
}
|
|
static peer_t*
|
|
select_and_cluster(double t)
|
|
{
|
|
llist_t *item;
|
|
int i, j;
|
|
int size = 3 * G.peer_cnt;
|
|
/* for selection algorithm */
|
|
point_t point[size];
|
|
unsigned num_points, num_candidates;
|
|
double low, high;
|
|
unsigned num_falsetickers;
|
|
/* for cluster algorithm */
|
|
survivor_t survivor[size];
|
|
unsigned num_survivors;
|
|
|
|
/* Selection */
|
|
|
|
num_points = 0;
|
|
item = G.ntp_peers;
|
|
while (item != NULL) {
|
|
peer_t *p = (peer_t *) item->data;
|
|
double rd = root_distance(p, t);
|
|
double offset = p->filter_offset;
|
|
|
|
if (!fit(p, rd)) {
|
|
item = item->link;
|
|
continue;
|
|
}
|
|
|
|
VERB4 bb_error_msg("interval: [%f %f %f] %s",
|
|
offset - rd,
|
|
offset,
|
|
offset + rd,
|
|
p->p_dotted
|
|
);
|
|
point[num_points].p = p;
|
|
point[num_points].type = -1;
|
|
point[num_points].edge = offset - rd;
|
|
num_points++;
|
|
point[num_points].p = p;
|
|
point[num_points].type = 0;
|
|
point[num_points].edge = offset;
|
|
num_points++;
|
|
point[num_points].p = p;
|
|
point[num_points].type = 1;
|
|
point[num_points].edge = offset + rd;
|
|
num_points++;
|
|
item = item->link;
|
|
}
|
|
num_candidates = num_points / 3;
|
|
if (num_candidates == 0) {
|
|
VERB3 bb_error_msg("no valid datapoints, no peer selected");
|
|
return NULL; /* never happers? */
|
|
}
|
|
//TODO: sorting does not seem to be done in reference code
|
|
qsort(point, num_points, sizeof(point[0]), compare_point_edge);
|
|
|
|
/* Start with the assumption that there are no falsetickers.
|
|
* Attempt to find a nonempty intersection interval containing
|
|
* the midpoints of all truechimers.
|
|
* If a nonempty interval cannot be found, increase the number
|
|
* of assumed falsetickers by one and try again.
|
|
* If a nonempty interval is found and the number of falsetickers
|
|
* is less than the number of truechimers, a majority has been found
|
|
* and the midpoint of each truechimer represents
|
|
* the candidates available to the cluster algorithm.
|
|
*/
|
|
num_falsetickers = 0;
|
|
while (1) {
|
|
int c;
|
|
unsigned num_midpoints = 0;
|
|
|
|
low = 1 << 9;
|
|
high = - (1 << 9);
|
|
c = 0;
|
|
for (i = 0; i < num_points; i++) {
|
|
/* We want to do:
|
|
* if (point[i].type == -1) c++;
|
|
* if (point[i].type == 1) c--;
|
|
* and it's simpler to do it this way:
|
|
*/
|
|
c -= point[i].type;
|
|
if (c >= num_candidates - num_falsetickers) {
|
|
/* If it was c++ and it got big enough... */
|
|
low = point[i].edge;
|
|
break;
|
|
}
|
|
if (point[i].type == 0)
|
|
num_midpoints++;
|
|
}
|
|
c = 0;
|
|
for (i = num_points-1; i >= 0; i--) {
|
|
c += point[i].type;
|
|
if (c >= num_candidates - num_falsetickers) {
|
|
high = point[i].edge;
|
|
break;
|
|
}
|
|
if (point[i].type == 0)
|
|
num_midpoints++;
|
|
}
|
|
/* If the number of midpoints is greater than the number
|
|
* of allowed falsetickers, the intersection contains at
|
|
* least one truechimer with no midpoint - bad.
|
|
* Also, interval should be nonempty.
|
|
*/
|
|
if (num_midpoints <= num_falsetickers && low < high)
|
|
break;
|
|
num_falsetickers++;
|
|
if (num_falsetickers * 2 >= num_candidates) {
|
|
VERB3 bb_error_msg("too many falsetickers:%d (candidates:%d), no peer selected",
|
|
num_falsetickers, num_candidates);
|
|
return NULL;
|
|
}
|
|
}
|
|
VERB3 bb_error_msg("selected interval: [%f, %f]; candidates:%d falsetickers:%d",
|
|
low, high, num_candidates, num_falsetickers);
|
|
|
|
/* Clustering */
|
|
|
|
/* Construct a list of survivors (p, metric)
|
|
* from the chime list, where metric is dominated
|
|
* first by stratum and then by root distance.
|
|
* All other things being equal, this is the order of preference.
|
|
*/
|
|
num_survivors = 0;
|
|
for (i = 0; i < num_points; i++) {
|
|
peer_t *p;
|
|
|
|
if (point[i].edge < low || point[i].edge > high)
|
|
continue;
|
|
p = point[i].p;
|
|
survivor[num_survivors].p = p;
|
|
//TODO: save root_distance in point_t and reuse here?
|
|
survivor[num_survivors].metric = MAXDIST * p->lastpkt_stratum + root_distance(p, t);
|
|
VERB4 bb_error_msg("survivor[%d] metric:%f peer:%s",
|
|
num_survivors, survivor[num_survivors].metric, p->p_dotted);
|
|
num_survivors++;
|
|
}
|
|
/* There must be at least MIN_SELECTED survivors to satisfy the
|
|
* correctness assertions. Ordinarily, the Byzantine criteria
|
|
* require four survivors, but for the demonstration here, one
|
|
* is acceptable.
|
|
*/
|
|
if (num_survivors < MIN_SELECTED) {
|
|
VERB3 bb_error_msg("num_survivors %d < %d, no peer selected",
|
|
num_survivors, MIN_SELECTED);
|
|
return NULL;
|
|
}
|
|
|
|
//looks like this is ONLY used by the fact that later we pick survivor[0].
|
|
//we can avoid sorting then, just find the minimum once!
|
|
qsort(survivor, num_survivors, sizeof(survivor[0]), compare_survivor_metric);
|
|
|
|
/* For each association p in turn, calculate the selection
|
|
* jitter p->sjitter as the square root of the sum of squares
|
|
* (p->offset - q->offset) over all q associations. The idea is
|
|
* to repeatedly discard the survivor with maximum selection
|
|
* jitter until a termination condition is met.
|
|
*/
|
|
while (1) {
|
|
unsigned max_idx = max_idx;
|
|
double max_selection_jitter = max_selection_jitter;
|
|
double min_jitter = min_jitter;
|
|
|
|
if (num_survivors <= MIN_CLUSTERED) {
|
|
bb_error_msg("num_survivors %d <= %d, not discarding more",
|
|
num_survivors, MIN_CLUSTERED);
|
|
break;
|
|
}
|
|
|
|
/* To make sure a few survivors are left
|
|
* for the clustering algorithm to chew on,
|
|
* we stop if the number of survivors
|
|
* is less than or equal to MIN_CLUSTERED (3).
|
|
*/
|
|
for (i = 0; i < num_survivors; i++) {
|
|
double selection_jitter_sq;
|
|
peer_t *p = survivor[i].p;
|
|
|
|
if (i == 0 || p->filter_jitter < min_jitter)
|
|
min_jitter = p->filter_jitter;
|
|
|
|
selection_jitter_sq = 0;
|
|
for (j = 0; j < num_survivors; j++) {
|
|
peer_t *q = survivor[j].p;
|
|
//TODO: where is 1/(n-1) * ... multiplier?
|
|
selection_jitter_sq += SQUARE(p->filter_offset - q->filter_offset);
|
|
}
|
|
if (i == 0 || selection_jitter_sq > max_selection_jitter) {
|
|
max_selection_jitter = selection_jitter_sq;
|
|
max_idx = i;
|
|
}
|
|
VERB5 bb_error_msg("survivor %d selection_jitter^2:%f",
|
|
i, selection_jitter_sq);
|
|
}
|
|
max_selection_jitter = SQRT(max_selection_jitter);
|
|
VERB4 bb_error_msg("max_selection_jitter (at %d):%f min_jitter:%f",
|
|
max_idx, max_selection_jitter, min_jitter);
|
|
|
|
/* If the maximum selection jitter is less than the
|
|
* minimum peer jitter, then tossing out more survivors
|
|
* will not lower the minimum peer jitter, so we might
|
|
* as well stop.
|
|
*/
|
|
if (max_selection_jitter < min_jitter) {
|
|
VERB3 bb_error_msg("max_selection_jitter:%f < min_jitter:%f, num_survivors:%d, not discarding more",
|
|
max_selection_jitter, min_jitter, num_survivors);
|
|
break;
|
|
}
|
|
|
|
/* Delete survivor[max_idx] from the list
|
|
* and go around again.
|
|
*/
|
|
VERB5 bb_error_msg("dropping survivor %d", max_idx);
|
|
num_survivors--;
|
|
while (max_idx < num_survivors) {
|
|
survivor[max_idx] = survivor[max_idx + 1];
|
|
max_idx++;
|
|
}
|
|
}
|
|
|
|
/* Pick the best clock. If the old system peer is on the list
|
|
* and at the same stratum as the first survivor on the list,
|
|
* then don't do a clock hop. Otherwise, select the first
|
|
* survivor on the list as the new system peer.
|
|
*/
|
|
//TODO - see clock_combine()
|
|
VERB3 bb_error_msg("selected peer %s filter_offset:%f age:%f",
|
|
survivor[0].p->p_dotted,
|
|
survivor[0].p->filter_offset,
|
|
t - survivor[0].p->lastpkt_recv_time
|
|
);
|
|
return survivor[0].p;
|
|
}
|
|
|
|
|
|
/*
|
|
* Local clock discipline and its helpers
|
|
*/
|
|
static void
|
|
set_new_values(int disc_state, double offset, double recv_time)
|
|
{
|
|
/* Enter new state and set state variables. Note we use the time
|
|
* of the last clock filter sample, which must be earlier than
|
|
* the current time.
|
|
*/
|
|
VERB3 bb_error_msg("disc_state=%d last_update_offset=%f last_update_recv_time=%f",
|
|
disc_state, offset, recv_time);
|
|
G.discipline_state = disc_state;
|
|
G.last_update_offset = offset;
|
|
G.last_update_recv_time = recv_time;
|
|
}
|
|
/* Clock state definitions */
|
|
#define STATE_NSET 0 /* initial state, "nothing is set" */
|
|
#define STATE_FSET 1 /* frequency set from file */
|
|
#define STATE_SPIK 2 /* spike detected */
|
|
#define STATE_FREQ 3 /* initial frequency */
|
|
#define STATE_SYNC 4 /* clock synchronized (normal operation) */
|
|
/* Return: -1: decrease poll interval, 0: leave as is, 1: increase */
|
|
static int
|
|
update_local_clock(peer_t *p, double t)
|
|
{
|
|
int rc;
|
|
long old_tmx_offset;
|
|
struct timex tmx;
|
|
double offset = p->filter_offset;
|
|
double recv_time = p->lastpkt_recv_time;
|
|
double abs_offset;
|
|
double freq_drift;
|
|
double since_last_update;
|
|
double etemp, dtemp;
|
|
|
|
abs_offset = fabs(offset);
|
|
|
|
/* If the offset is too large, give up and go home */
|
|
if (abs_offset > PANIC_THRESHOLD) {
|
|
bb_error_msg_and_die("offset %f far too big, exiting", offset);
|
|
}
|
|
|
|
/* If this is an old update, for instance as the result
|
|
* of a system peer change, avoid it. We never use
|
|
* an old sample or the same sample twice.
|
|
*/
|
|
if (recv_time <= G.last_update_recv_time) {
|
|
VERB3 bb_error_msg("same or older datapoint: %f >= %f, not using it",
|
|
G.last_update_recv_time, recv_time);
|
|
return 0; /* "leave poll interval as is" */
|
|
}
|
|
|
|
/* Clock state machine transition function. This is where the
|
|
* action is and defines how the system reacts to large time
|
|
* and frequency errors.
|
|
*/
|
|
since_last_update = recv_time - G.reftime;
|
|
freq_drift = 0;
|
|
if (G.discipline_state == STATE_FREQ) {
|
|
/* Ignore updates until the stepout threshold */
|
|
if (since_last_update < WATCH_THRESHOLD) {
|
|
VERB3 bb_error_msg("measuring drift, datapoint ignored, %f sec remains",
|
|
WATCH_THRESHOLD - since_last_update);
|
|
return 0; /* "leave poll interval as is" */
|
|
}
|
|
freq_drift = (offset - G.last_update_offset) / since_last_update;
|
|
}
|
|
|
|
/* There are two main regimes: when the
|
|
* offset exceeds the step threshold and when it does not.
|
|
*/
|
|
if (abs_offset > STEP_THRESHOLD) {
|
|
llist_t *item;
|
|
|
|
switch (G.discipline_state) {
|
|
case STATE_SYNC:
|
|
/* The first outlyer: ignore it, switch to SPIK state */
|
|
VERB3 bb_error_msg("offset:%f - spike detected", offset);
|
|
G.discipline_state = STATE_SPIK;
|
|
return -1; /* "decrease poll interval" */
|
|
|
|
case STATE_SPIK:
|
|
/* Ignore succeeding outlyers until either an inlyer
|
|
* is found or the stepout threshold is exceeded.
|
|
*/
|
|
if (since_last_update < WATCH_THRESHOLD) {
|
|
VERB3 bb_error_msg("spike detected, datapoint ignored, %f sec remains",
|
|
WATCH_THRESHOLD - since_last_update);
|
|
return -1; /* "decrease poll interval" */
|
|
}
|
|
/* fall through: we need to step */
|
|
} /* switch */
|
|
|
|
/* Step the time and clamp down the poll interval.
|
|
*
|
|
* In NSET state an initial frequency correction is
|
|
* not available, usually because the frequency file has
|
|
* not yet been written. Since the time is outside the
|
|
* capture range, the clock is stepped. The frequency
|
|
* will be set directly following the stepout interval.
|
|
*
|
|
* In FSET state the initial frequency has been set
|
|
* from the frequency file. Since the time is outside
|
|
* the capture range, the clock is stepped immediately,
|
|
* rather than after the stepout interval. Guys get
|
|
* nervous if it takes 17 minutes to set the clock for
|
|
* the first time.
|
|
*
|
|
* In SPIK state the stepout threshold has expired and
|
|
* the phase is still above the step threshold. Note
|
|
* that a single spike greater than the step threshold
|
|
* is always suppressed, even at the longer poll
|
|
* intervals.
|
|
*/
|
|
VERB3 bb_error_msg("stepping time by %f; poll_exp=MINPOLL", offset);
|
|
step_time(offset);
|
|
if (option_mask32 & OPT_q) {
|
|
/* We were only asked to set time once. Done. */
|
|
exit(0);
|
|
}
|
|
|
|
G.polladj_count = 0;
|
|
G.poll_exp = MINPOLL;
|
|
G.stratum = MAXSTRAT;
|
|
for (item = G.ntp_peers; item != NULL; item = item->link) {
|
|
peer_t *pp = (peer_t *) item->data;
|
|
reset_peer_stats(pp, t, offset);
|
|
}
|
|
if (G.discipline_state == STATE_NSET) {
|
|
set_new_values(STATE_FREQ, /*offset:*/ 0, recv_time);
|
|
return 1; /* "ok to increase poll interval" */
|
|
}
|
|
set_new_values(STATE_SYNC, /*offset:*/ 0, recv_time);
|
|
|
|
} else { /* abs_offset <= STEP_THRESHOLD */
|
|
|
|
if (G.poll_exp < MINPOLL) {
|
|
VERB3 bb_error_msg("saw small offset %f, disabling burst mode", offset);
|
|
G.poll_exp = MINPOLL;
|
|
}
|
|
|
|
/* Compute the clock jitter as the RMS of exponentially
|
|
* weighted offset differences. Used by the poll adjust code.
|
|
*/
|
|
etemp = SQUARE(G.discipline_jitter);
|
|
dtemp = SQUARE(MAXD(fabs(offset - G.last_update_offset), G_precision_sec));
|
|
G.discipline_jitter = SQRT(etemp + (dtemp - etemp) / AVG);
|
|
VERB3 bb_error_msg("discipline jitter=%f", G.discipline_jitter);
|
|
|
|
switch (G.discipline_state) {
|
|
case STATE_NSET:
|
|
if (option_mask32 & OPT_q) {
|
|
/* We were only asked to set time once.
|
|
* The clock is precise enough, no need to step.
|
|
*/
|
|
exit(0);
|
|
}
|
|
/* This is the first update received and the frequency
|
|
* has not been initialized. The first thing to do
|
|
* is directly measure the oscillator frequency.
|
|
*/
|
|
set_new_values(STATE_FREQ, offset, recv_time);
|
|
VERB3 bb_error_msg("transitioning to FREQ, datapoint ignored");
|
|
return -1; /* "decrease poll interval" */
|
|
|
|
#if 0 /* this is dead code for now */
|
|
case STATE_FSET:
|
|
/* This is the first update and the frequency
|
|
* has been initialized. Adjust the phase, but
|
|
* don't adjust the frequency until the next update.
|
|
*/
|
|
set_new_values(STATE_SYNC, offset, recv_time);
|
|
/* freq_drift remains 0 */
|
|
break;
|
|
#endif
|
|
|
|
case STATE_FREQ:
|
|
/* since_last_update >= WATCH_THRESHOLD, we waited enough.
|
|
* Correct the phase and frequency and switch to SYNC state.
|
|
* freq_drift was already estimated (see code above)
|
|
*/
|
|
set_new_values(STATE_SYNC, offset, recv_time);
|
|
break;
|
|
|
|
default:
|
|
/* Compute freq_drift due to PLL and FLL contributions.
|
|
*
|
|
* The FLL and PLL frequency gain constants
|
|
* depend on the poll interval and Allan
|
|
* intercept. The FLL is not used below one-half
|
|
* the Allan intercept. Above that the loop gain
|
|
* increases in steps to 1 / AVG.
|
|
*/
|
|
if ((1 << G.poll_exp) > ALLAN / 2) {
|
|
etemp = FLL - G.poll_exp;
|
|
if (etemp < AVG)
|
|
etemp = AVG;
|
|
freq_drift += (offset - G.last_update_offset) / (MAXD(since_last_update, ALLAN) * etemp);
|
|
}
|
|
/* For the PLL the integration interval
|
|
* (numerator) is the minimum of the update
|
|
* interval and poll interval. This allows
|
|
* oversampling, but not undersampling.
|
|
*/
|
|
etemp = MIND(since_last_update, (1 << G.poll_exp));
|
|
dtemp = (4 * PLL) << G.poll_exp;
|
|
freq_drift += offset * etemp / SQUARE(dtemp);
|
|
set_new_values(STATE_SYNC, offset, recv_time);
|
|
break;
|
|
}
|
|
G.stratum = p->lastpkt_stratum + 1;
|
|
}
|
|
|
|
G.reftime = t;
|
|
G.leap = p->lastpkt_leap;
|
|
G.refid = p->lastpkt_refid;
|
|
G.rootdelay = p->lastpkt_rootdelay + p->lastpkt_delay;
|
|
dtemp = p->filter_jitter; // SQRT(SQUARE(p->filter_jitter) + SQUARE(s.jitter));
|
|
dtemp += MAXD(p->filter_dispersion + FREQ_TOLERANCE * (t - p->lastpkt_recv_time) + abs_offset, MINDISP);
|
|
G.rootdisp = p->lastpkt_rootdisp + dtemp;
|
|
VERB3 bb_error_msg("updating leap/refid/reftime/rootdisp from peer %s", p->p_dotted);
|
|
|
|
/* We are in STATE_SYNC now, but did not do adjtimex yet.
|
|
* (Any other state does not reach this, they all return earlier)
|
|
* By this time, freq_drift and G.last_update_offset are set
|
|
* to values suitable for adjtimex.
|
|
*/
|
|
#if !USING_KERNEL_PLL_LOOP
|
|
/* Calculate the new frequency drift and frequency stability (wander).
|
|
* Compute the clock wander as the RMS of exponentially weighted
|
|
* frequency differences. This is not used directly, but can,
|
|
* along with the jitter, be a highly useful monitoring and
|
|
* debugging tool.
|
|
*/
|
|
dtemp = G.discipline_freq_drift + freq_drift;
|
|
G.discipline_freq_drift = MAXD(MIND(MAXDRIFT, dtemp), -MAXDRIFT);
|
|
etemp = SQUARE(G.discipline_wander);
|
|
dtemp = SQUARE(dtemp);
|
|
G.discipline_wander = SQRT(etemp + (dtemp - etemp) / AVG);
|
|
|
|
VERB3 bb_error_msg("discipline freq_drift=%.9f(int:%ld corr:%e) wander=%f",
|
|
G.discipline_freq_drift,
|
|
(long)(G.discipline_freq_drift * 65536e6),
|
|
freq_drift,
|
|
G.discipline_wander);
|
|
#endif
|
|
VERB3 {
|
|
memset(&tmx, 0, sizeof(tmx));
|
|
if (adjtimex(&tmx) < 0)
|
|
bb_perror_msg_and_die("adjtimex");
|
|
VERB3 bb_error_msg("p adjtimex freq:%ld offset:%ld constant:%ld status:0x%x",
|
|
tmx.freq, tmx.offset, tmx.constant, tmx.status);
|
|
}
|
|
|
|
old_tmx_offset = 0;
|
|
if (!G.adjtimex_was_done) {
|
|
G.adjtimex_was_done = 1;
|
|
/* When we use adjtimex for the very first time,
|
|
* we need to ADD to pre-existing tmx.offset - it may be !0
|
|
*/
|
|
memset(&tmx, 0, sizeof(tmx));
|
|
if (adjtimex(&tmx) < 0)
|
|
bb_perror_msg_and_die("adjtimex");
|
|
old_tmx_offset = tmx.offset;
|
|
}
|
|
memset(&tmx, 0, sizeof(tmx));
|
|
#if 0
|
|
//doesn't work, offset remains 0 (!) in kernel:
|
|
//ntpd: set adjtimex freq:1786097 tmx.offset:77487
|
|
//ntpd: prev adjtimex freq:1786097 tmx.offset:0
|
|
//ntpd: cur adjtimex freq:1786097 tmx.offset:0
|
|
tmx.modes = ADJ_FREQUENCY | ADJ_OFFSET;
|
|
/* 65536 is one ppm */
|
|
tmx.freq = G.discipline_freq_drift * 65536e6;
|
|
tmx.offset = G.last_update_offset * 1000000; /* usec */
|
|
#endif
|
|
tmx.modes = ADJ_OFFSET | ADJ_STATUS | ADJ_TIMECONST;// | ADJ_MAXERROR | ADJ_ESTERROR;
|
|
tmx.offset = (G.last_update_offset * 1000000) /* usec */
|
|
/* + (G.last_update_offset < 0 ? -0.5 : 0.5) - too small to bother */
|
|
+ old_tmx_offset; /* almost always 0 */
|
|
tmx.status = STA_PLL;
|
|
//if (sys_leap == LEAP_ADDSECOND)
|
|
// tmx.status |= STA_INS;
|
|
//else if (sys_leap == LEAP_DELSECOND)
|
|
// tmx.status |= STA_DEL;
|
|
tmx.constant = G.poll_exp - 4;
|
|
//tmx.esterror = (u_int32)(clock_jitter * 1e6);
|
|
//tmx.maxerror = (u_int32)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
|
|
VERB3 bb_error_msg("b adjtimex freq:%ld offset:%ld constant:%ld status:0x%x",
|
|
tmx.freq, tmx.offset, tmx.constant, tmx.status);
|
|
rc = adjtimex(&tmx);
|
|
if (rc < 0)
|
|
bb_perror_msg_and_die("adjtimex");
|
|
if (G.kernel_freq_drift != tmx.freq / 65536) {
|
|
G.kernel_freq_drift = tmx.freq / 65536;
|
|
VERB2 bb_error_msg("kernel clock drift: %ld ppm", G.kernel_freq_drift);
|
|
}
|
|
VERB3 {
|
|
bb_error_msg("adjtimex:%d freq:%ld offset:%ld constant:%ld status:0x%x",
|
|
rc, tmx.freq, tmx.offset, tmx.constant, tmx.status);
|
|
#if 0
|
|
/* always gives the same output as above msg */
|
|
memset(&tmx, 0, sizeof(tmx));
|
|
if (adjtimex(&tmx) < 0)
|
|
bb_perror_msg_and_die("adjtimex");
|
|
VERB3 bb_error_msg("c adjtimex freq:%ld offset:%ld constant:%ld status:0x%x",
|
|
tmx.freq, tmx.offset, tmx.constant, tmx.status);
|
|
#endif
|
|
}
|
|
// #define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */ - ?
|
|
// it appeared after a while:
|
|
//ntpd: p adjtimex freq:-14545653 offset:-5396 constant:10 status:0x41
|
|
//ntpd: c adjtimex freq:-14547835 offset:-8307 constant:10 status:0x1
|
|
//ntpd: p adjtimex freq:-14547835 offset:-6398 constant:10 status:0x41
|
|
//ntpd: c adjtimex freq:-14550486 offset:-10158 constant:10 status:0x1
|
|
//ntpd: p adjtimex freq:-14550486 offset:-6132 constant:10 status:0x41
|
|
//ntpd: c adjtimex freq:-14636129 offset:-10158 constant:10 status:0x4001
|
|
//ntpd: p adjtimex freq:-14636129 offset:-10002 constant:10 status:0x4041
|
|
//ntpd: c adjtimex freq:-14636245 offset:-7497 constant:10 status:0x1
|
|
//ntpd: p adjtimex freq:-14636245 offset:-4573 constant:10 status:0x41
|
|
//ntpd: c adjtimex freq:-14642034 offset:-11715 constant:10 status:0x1
|
|
//ntpd: p adjtimex freq:-14642034 offset:-4098 constant:10 status:0x41
|
|
//ntpd: c adjtimex freq:-14699112 offset:-11746 constant:10 status:0x4001
|
|
//ntpd: p adjtimex freq:-14699112 offset:-4239 constant:10 status:0x4041
|
|
//ntpd: c adjtimex freq:-14762330 offset:-12786 constant:10 status:0x4001
|
|
//ntpd: p adjtimex freq:-14762330 offset:-4434 constant:10 status:0x4041
|
|
//ntpd: b adjtimex freq:0 offset:-9669 constant:8 status:0x1
|
|
//ntpd: adjtimex:0 freq:-14809095 offset:-9669 constant:10 status:0x4001
|
|
//ntpd: c adjtimex freq:-14809095 offset:-9669 constant:10 status:0x4001
|
|
|
|
return 1; /* "ok to increase poll interval" */
|
|
}
|
|
|
|
|
|
/*
|
|
* We've got a new reply packet from a peer, process it
|
|
* (helpers first)
|
|
*/
|
|
static unsigned
|
|
retry_interval(void)
|
|
{
|
|
/* Local problem, want to retry soon */
|
|
unsigned interval, r;
|
|
interval = RETRY_INTERVAL;
|
|
r = random();
|
|
interval += r % (unsigned)(RETRY_INTERVAL / 4);
|
|
VERB3 bb_error_msg("chose retry interval:%u", interval);
|
|
return interval;
|
|
}
|
|
static unsigned
|
|
poll_interval(int exponent) /* exp is always -1 or 0 */
|
|
{
|
|
/* Want to send next packet at (1 << G.poll_exp) + small random value */
|
|
unsigned interval, r;
|
|
exponent += G.poll_exp; /* G.poll_exp is always > 0 */
|
|
/* never true: if (exp < 0) exp = 0; */
|
|
interval = 1 << exponent;
|
|
r = random();
|
|
interval += ((r & (interval-1)) >> 4) + ((r >> 8) & 1); /* + 1/16 of interval, max */
|
|
VERB3 bb_error_msg("chose poll interval:%u (poll_exp:%d exp:%d)", interval, G.poll_exp, exponent);
|
|
return interval;
|
|
}
|
|
static void
|
|
recv_and_process_peer_pkt(peer_t *p)
|
|
{
|
|
int rc;
|
|
ssize_t size;
|
|
msg_t msg;
|
|
double T1, T2, T3, T4;
|
|
unsigned interval;
|
|
datapoint_t *datapoint;
|
|
peer_t *q;
|
|
|
|
/* We can recvfrom here and check from.IP, but some multihomed
|
|
* ntp servers reply from their *other IP*.
|
|
* TODO: maybe we should check at least what we can: from.port == 123?
|
|
*/
|
|
size = recv(p->p_fd, &msg, sizeof(msg), MSG_DONTWAIT);
|
|
if (size == -1) {
|
|
bb_perror_msg("recv(%s) error", p->p_dotted);
|
|
if (errno == EHOSTUNREACH || errno == EHOSTDOWN
|
|
|| errno == ENETUNREACH || errno == ENETDOWN
|
|
|| errno == ECONNREFUSED || errno == EADDRNOTAVAIL
|
|
|| errno == EAGAIN
|
|
) {
|
|
//TODO: always do this?
|
|
set_next(p, retry_interval());
|
|
goto close_sock;
|
|
}
|
|
xfunc_die();
|
|
}
|
|
|
|
if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
|
|
bb_error_msg("malformed packet received from %s", p->p_dotted);
|
|
goto bail;
|
|
}
|
|
|
|
if (msg.m_orgtime.int_partl != p->p_xmt_msg.m_xmttime.int_partl
|
|
|| msg.m_orgtime.fractionl != p->p_xmt_msg.m_xmttime.fractionl
|
|
) {
|
|
goto bail;
|
|
}
|
|
|
|
if ((msg.m_status & LI_ALARM) == LI_ALARM
|
|
|| msg.m_stratum == 0
|
|
|| msg.m_stratum > NTP_MAXSTRATUM
|
|
) {
|
|
// TODO: stratum 0 responses may have commands in 32-bit m_refid field:
|
|
// "DENY", "RSTR" - peer does not like us at all
|
|
// "RATE" - peer is overloaded, reduce polling freq
|
|
interval = poll_interval(0);
|
|
bb_error_msg("reply from %s: not synced, next query in %us", p->p_dotted, interval);
|
|
goto close_sock;
|
|
}
|
|
|
|
// /*
|
|
// * Verify the server is synchronized with valid stratum and
|
|
// * reference time not later than the transmit time.
|
|
// */
|
|
// if (p->lastpkt_leap == NOSYNC || p->lastpkt_stratum >= MAXSTRAT)
|
|
// return; /* unsynchronized */
|
|
//
|
|
// /* Verify valid root distance */
|
|
// if (msg.m_rootdelay / 2 + msg.m_rootdisp >= MAXDISP || p->lastpkt_reftime > msg.m_xmt)
|
|
// return; /* invalid header values */
|
|
|
|
p->lastpkt_leap = msg.m_status;
|
|
p->lastpkt_rootdelay = sfp_to_d(msg.m_rootdelay);
|
|
p->lastpkt_rootdisp = sfp_to_d(msg.m_rootdisp);
|
|
p->lastpkt_refid = msg.m_refid;
|
|
|
|
/*
|
|
* From RFC 2030 (with a correction to the delay math):
|
|
*
|
|
* Timestamp Name ID When Generated
|
|
* ------------------------------------------------------------
|
|
* Originate Timestamp T1 time request sent by client
|
|
* Receive Timestamp T2 time request received by server
|
|
* Transmit Timestamp T3 time reply sent by server
|
|
* Destination Timestamp T4 time reply received by client
|
|
*
|
|
* The roundtrip delay and local clock offset are defined as
|
|
*
|
|
* delay = (T4 - T1) - (T3 - T2); offset = ((T2 - T1) + (T3 - T4)) / 2
|
|
*/
|
|
T1 = p->p_xmttime;
|
|
T2 = lfp_to_d(msg.m_rectime);
|
|
T3 = lfp_to_d(msg.m_xmttime);
|
|
T4 = gettime1900d();
|
|
|
|
p->lastpkt_recv_time = T4;
|
|
|
|
VERB5 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
|
|
p->datapoint_idx = p->p_reachable_bits ? (p->datapoint_idx + 1) % NUM_DATAPOINTS : 0;
|
|
datapoint = &p->filter_datapoint[p->datapoint_idx];
|
|
datapoint->d_recv_time = T4;
|
|
datapoint->d_offset = ((T2 - T1) + (T3 - T4)) / 2;
|
|
/* The delay calculation is a special case. In cases where the
|
|
* server and client clocks are running at different rates and
|
|
* with very fast networks, the delay can appear negative. In
|
|
* order to avoid violating the Principle of Least Astonishment,
|
|
* the delay is clamped not less than the system precision.
|
|
*/
|
|
p->lastpkt_delay = (T4 - T1) - (T3 - T2);
|
|
datapoint->d_dispersion = LOG2D(msg.m_precision_exp) + G_precision_sec;
|
|
if (!p->p_reachable_bits) {
|
|
/* 1st datapoint ever - replicate offset in every element */
|
|
int i;
|
|
for (i = 1; i < NUM_DATAPOINTS; i++) {
|
|
p->filter_datapoint[i].d_offset = datapoint->d_offset;
|
|
}
|
|
}
|
|
|
|
p->p_reachable_bits |= 1;
|
|
VERB1 {
|
|
bb_error_msg("reply from %s: reach 0x%02x offset %f delay %f",
|
|
p->p_dotted,
|
|
p->p_reachable_bits,
|
|
datapoint->d_offset, p->lastpkt_delay);
|
|
}
|
|
|
|
/* Muck with statictics and update the clock */
|
|
filter_datapoints(p, T4);
|
|
q = select_and_cluster(T4);
|
|
rc = -1;
|
|
if (q)
|
|
rc = update_local_clock(q, T4);
|
|
|
|
if (rc != 0) {
|
|
/* Adjust the poll interval by comparing the current offset
|
|
* with the clock jitter. If the offset is less than
|
|
* the clock jitter times a constant, then the averaging interval
|
|
* is increased, otherwise it is decreased. A bit of hysteresis
|
|
* helps calm the dance. Works best using burst mode.
|
|
*/
|
|
VERB4 if (rc > 0) {
|
|
bb_error_msg("offset:%f POLLADJ_GATE*discipline_jitter:%f poll:%s",
|
|
q->filter_offset, POLLADJ_GATE * G.discipline_jitter,
|
|
fabs(q->filter_offset) < POLLADJ_GATE * G.discipline_jitter
|
|
? "grows" : "falls"
|
|
);
|
|
}
|
|
if (rc > 0 && fabs(q->filter_offset) < POLLADJ_GATE * G.discipline_jitter) {
|
|
/* was += G.poll_exp but it is a bit
|
|
* too optimistic for my taste at high poll_exp's */
|
|
G.polladj_count += MINPOLL;
|
|
if (G.polladj_count > POLLADJ_LIMIT) {
|
|
G.polladj_count = 0;
|
|
if (G.poll_exp < MAXPOLL) {
|
|
G.poll_exp++;
|
|
VERB3 bb_error_msg("polladj: discipline_jitter:%f ++poll_exp=%d",
|
|
G.discipline_jitter, G.poll_exp);
|
|
}
|
|
} else {
|
|
VERB3 bb_error_msg("polladj: incr:%d", G.polladj_count);
|
|
}
|
|
} else {
|
|
G.polladj_count -= G.poll_exp * 2;
|
|
if (G.polladj_count < -POLLADJ_LIMIT) {
|
|
G.polladj_count = 0;
|
|
if (G.poll_exp > MINPOLL) {
|
|
G.poll_exp--;
|
|
VERB3 bb_error_msg("polladj: discipline_jitter:%f --poll_exp=%d",
|
|
G.discipline_jitter, G.poll_exp);
|
|
}
|
|
} else {
|
|
VERB3 bb_error_msg("polladj: decr:%d", G.polladj_count);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Decide when to send new query for this peer */
|
|
interval = poll_interval(0);
|
|
set_next(p, interval);
|
|
|
|
close_sock:
|
|
/* We do not expect any more packets from this peer for now.
|
|
* Closing the socket informs kernel about it.
|
|
* We open a new socket when we send a new query.
|
|
*/
|
|
close(p->p_fd);
|
|
p->p_fd = -1;
|
|
bail:
|
|
return;
|
|
}
|
|
|
|
#if ENABLE_FEATURE_NTPD_SERVER
|
|
static void
|
|
recv_and_process_client_pkt(void /*int fd*/)
|
|
{
|
|
ssize_t size;
|
|
uint8_t version;
|
|
double rectime;
|
|
len_and_sockaddr *to;
|
|
struct sockaddr *from;
|
|
msg_t msg;
|
|
uint8_t query_status;
|
|
l_fixedpt_t query_xmttime;
|
|
|
|
to = get_sock_lsa(G.listen_fd);
|
|
from = xzalloc(to->len);
|
|
|
|
size = recv_from_to(G.listen_fd, &msg, sizeof(msg), MSG_DONTWAIT, from, &to->u.sa, to->len);
|
|
if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
|
|
char *addr;
|
|
if (size < 0) {
|
|
if (errno == EAGAIN)
|
|
goto bail;
|
|
bb_perror_msg_and_die("recv");
|
|
}
|
|
addr = xmalloc_sockaddr2dotted_noport(from);
|
|
bb_error_msg("malformed packet received from %s: size %u", addr, (int)size);
|
|
free(addr);
|
|
goto bail;
|
|
}
|
|
|
|
query_status = msg.m_status;
|
|
query_xmttime = msg.m_xmttime;
|
|
|
|
/* Build a reply packet */
|
|
memset(&msg, 0, sizeof(msg));
|
|
msg.m_status = G.stratum < MAXSTRAT ? G.leap : LI_ALARM;
|
|
msg.m_status |= (query_status & VERSION_MASK);
|
|
msg.m_status |= ((query_status & MODE_MASK) == MODE_CLIENT) ?
|
|
MODE_SERVER : MODE_SYM_PAS;
|
|
msg.m_stratum = G.stratum;
|
|
msg.m_ppoll = G.poll_exp;
|
|
msg.m_precision_exp = G_precision_exp;
|
|
rectime = gettime1900d();
|
|
msg.m_xmttime = msg.m_rectime = d_to_lfp(rectime);
|
|
msg.m_reftime = d_to_lfp(G.reftime);
|
|
msg.m_orgtime = query_xmttime;
|
|
msg.m_rootdelay = d_to_sfp(G.rootdelay);
|
|
//simple code does not do this, fix simple code!
|
|
msg.m_rootdisp = d_to_sfp(G.rootdisp);
|
|
version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
|
|
msg.m_refid = G.refid; // (version > (3 << VERSION_SHIFT)) ? G.refid : G.refid3;
|
|
|
|
/* We reply from the local address packet was sent to,
|
|
* this makes to/from look swapped here: */
|
|
do_sendto(G.listen_fd,
|
|
/*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
|
|
&msg, size);
|
|
|
|
bail:
|
|
free(to);
|
|
free(from);
|
|
}
|
|
#endif
|
|
|
|
/* Upstream ntpd's options:
|
|
*
|
|
* -4 Force DNS resolution of host names to the IPv4 namespace.
|
|
* -6 Force DNS resolution of host names to the IPv6 namespace.
|
|
* -a Require cryptographic authentication for broadcast client,
|
|
* multicast client and symmetric passive associations.
|
|
* This is the default.
|
|
* -A Do not require cryptographic authentication for broadcast client,
|
|
* multicast client and symmetric passive associations.
|
|
* This is almost never a good idea.
|
|
* -b Enable the client to synchronize to broadcast servers.
|
|
* -c conffile
|
|
* Specify the name and path of the configuration file,
|
|
* default /etc/ntp.conf
|
|
* -d Specify debugging mode. This option may occur more than once,
|
|
* with each occurrence indicating greater detail of display.
|
|
* -D level
|
|
* Specify debugging level directly.
|
|
* -f driftfile
|
|
* Specify the name and path of the frequency file.
|
|
* This is the same operation as the "driftfile FILE"
|
|
* configuration command.
|
|
* -g Normally, ntpd exits with a message to the system log
|
|
* if the offset exceeds the panic threshold, which is 1000 s
|
|
* by default. This option allows the time to be set to any value
|
|
* without restriction; however, this can happen only once.
|
|
* If the threshold is exceeded after that, ntpd will exit
|
|
* with a message to the system log. This option can be used
|
|
* with the -q and -x options. See the tinker command for other options.
|
|
* -i jaildir
|
|
* Chroot the server to the directory jaildir. This option also implies
|
|
* that the server attempts to drop root privileges at startup
|
|
* (otherwise, chroot gives very little additional security).
|
|
* You may need to also specify a -u option.
|
|
* -k keyfile
|
|
* Specify the name and path of the symmetric key file,
|
|
* default /etc/ntp/keys. This is the same operation
|
|
* as the "keys FILE" configuration command.
|
|
* -l logfile
|
|
* Specify the name and path of the log file. The default
|
|
* is the system log file. This is the same operation as
|
|
* the "logfile FILE" configuration command.
|
|
* -L Do not listen to virtual IPs. The default is to listen.
|
|
* -n Don't fork.
|
|
* -N To the extent permitted by the operating system,
|
|
* run the ntpd at the highest priority.
|
|
* -p pidfile
|
|
* Specify the name and path of the file used to record the ntpd
|
|
* process ID. This is the same operation as the "pidfile FILE"
|
|
* configuration command.
|
|
* -P priority
|
|
* To the extent permitted by the operating system,
|
|
* run the ntpd at the specified priority.
|
|
* -q Exit the ntpd just after the first time the clock is set.
|
|
* This behavior mimics that of the ntpdate program, which is
|
|
* to be retired. The -g and -x options can be used with this option.
|
|
* Note: The kernel time discipline is disabled with this option.
|
|
* -r broadcastdelay
|
|
* Specify the default propagation delay from the broadcast/multicast
|
|
* server to this client. This is necessary only if the delay
|
|
* cannot be computed automatically by the protocol.
|
|
* -s statsdir
|
|
* Specify the directory path for files created by the statistics
|
|
* facility. This is the same operation as the "statsdir DIR"
|
|
* configuration command.
|
|
* -t key
|
|
* Add a key number to the trusted key list. This option can occur
|
|
* more than once.
|
|
* -u user[:group]
|
|
* Specify a user, and optionally a group, to switch to.
|
|
* -v variable
|
|
* -V variable
|
|
* Add a system variable listed by default.
|
|
* -x Normally, the time is slewed if the offset is less than the step
|
|
* threshold, which is 128 ms by default, and stepped if above
|
|
* the threshold. This option sets the threshold to 600 s, which is
|
|
* well within the accuracy window to set the clock manually.
|
|
* Note: since the slew rate of typical Unix kernels is limited
|
|
* to 0.5 ms/s, each second of adjustment requires an amortization
|
|
* interval of 2000 s. Thus, an adjustment as much as 600 s
|
|
* will take almost 14 days to complete. This option can be used
|
|
* with the -g and -q options. See the tinker command for other options.
|
|
* Note: The kernel time discipline is disabled with this option.
|
|
*/
|
|
|
|
/* By doing init in a separate function we decrease stack usage
|
|
* in main loop.
|
|
*/
|
|
static NOINLINE void ntp_init(char **argv)
|
|
{
|
|
unsigned opts;
|
|
llist_t *peers;
|
|
|
|
srandom(getpid());
|
|
|
|
if (getuid())
|
|
bb_error_msg_and_die(bb_msg_you_must_be_root);
|
|
|
|
/* Set some globals */
|
|
#if 0
|
|
/* With constant b = 100, G.precision_exp is also constant -6.
|
|
* Uncomment this to verify.
|
|
*/
|
|
{
|
|
int prec = 0;
|
|
int b;
|
|
# if 0
|
|
struct timespec tp;
|
|
/* We can use sys_clock_getres but assuming 10ms tick should be fine */
|
|
clock_getres(CLOCK_REALTIME, &tp);
|
|
tp.tv_sec = 0;
|
|
tp.tv_nsec = 10000000;
|
|
b = 1000000000 / tp.tv_nsec; /* convert to Hz */
|
|
# else
|
|
b = 100; /* b = 1000000000/10000000 = 100 */
|
|
# endif
|
|
while (b > 1)
|
|
prec--, b >>= 1;
|
|
/*G.precision_exp = prec;*/
|
|
/*G.precision_sec = (1.0 / (1 << (- prec)));*/
|
|
bb_error_msg("G.precision_exp:%d sec:%f", prec, G_precision_sec); /* -6 */
|
|
}
|
|
#endif
|
|
G.stratum = MAXSTRAT;
|
|
G.poll_exp = 1; /* should use MINPOLL, but 1 speeds up initial sync */
|
|
G.reftime = G.last_update_recv_time = gettime1900d();
|
|
|
|
/* Parse options */
|
|
peers = NULL;
|
|
opt_complementary = "dd:p::"; /* d: counter, p: list */
|
|
opts = getopt32(argv,
|
|
"nqNx" /* compat */
|
|
"p:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
|
|
"d" /* compat */
|
|
"46aAbgL", /* compat, ignored */
|
|
&peers, &G.verbose);
|
|
if (!(opts & (OPT_p|OPT_l)))
|
|
bb_show_usage();
|
|
// if (opts & OPT_x) /* disable stepping, only slew is allowed */
|
|
// G.time_was_stepped = 1;
|
|
while (peers)
|
|
add_peers(llist_pop(&peers));
|
|
if (!(opts & OPT_n)) {
|
|
bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO, argv);
|
|
logmode = LOGMODE_NONE;
|
|
}
|
|
#if ENABLE_FEATURE_NTPD_SERVER
|
|
G.listen_fd = -1;
|
|
if (opts & OPT_l) {
|
|
G.listen_fd = create_and_bind_dgram_or_die(NULL, 123);
|
|
socket_want_pktinfo(G.listen_fd);
|
|
setsockopt(G.listen_fd, IPPROTO_IP, IP_TOS, &const_IPTOS_LOWDELAY, sizeof(const_IPTOS_LOWDELAY));
|
|
}
|
|
#endif
|
|
/* I hesitate to set -20 prio. -15 should be high enough for timekeeping */
|
|
if (opts & OPT_N)
|
|
setpriority(PRIO_PROCESS, 0, -15);
|
|
|
|
bb_signals((1 << SIGTERM) | (1 << SIGINT), record_signo);
|
|
bb_signals((1 << SIGPIPE) | (1 << SIGHUP), SIG_IGN);
|
|
}
|
|
|
|
int ntpd_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
|
int ntpd_main(int argc UNUSED_PARAM, char **argv)
|
|
{
|
|
struct globals g;
|
|
struct pollfd *pfd;
|
|
peer_t **idx2peer;
|
|
|
|
memset(&g, 0, sizeof(g));
|
|
SET_PTR_TO_GLOBALS(&g);
|
|
|
|
ntp_init(argv);
|
|
|
|
{
|
|
/* if ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
|
|
unsigned cnt = g.peer_cnt + ENABLE_FEATURE_NTPD_SERVER;
|
|
idx2peer = xzalloc(sizeof(idx2peer[0]) * cnt);
|
|
pfd = xzalloc(sizeof(pfd[0]) * cnt);
|
|
}
|
|
|
|
while (!bb_got_signal) {
|
|
llist_t *item;
|
|
unsigned i, j;
|
|
unsigned sent_cnt, trial_cnt;
|
|
int nfds, timeout;
|
|
time_t cur_time, nextaction;
|
|
|
|
/* Nothing between here and poll() blocks for any significant time */
|
|
|
|
cur_time = time(NULL);
|
|
nextaction = cur_time + 3600;
|
|
|
|
i = 0;
|
|
#if ENABLE_FEATURE_NTPD_SERVER
|
|
if (g.listen_fd != -1) {
|
|
pfd[0].fd = g.listen_fd;
|
|
pfd[0].events = POLLIN;
|
|
i++;
|
|
}
|
|
#endif
|
|
/* Pass over peer list, send requests, time out on receives */
|
|
sent_cnt = trial_cnt = 0;
|
|
for (item = g.ntp_peers; item != NULL; item = item->link) {
|
|
peer_t *p = (peer_t *) item->data;
|
|
|
|
/* Overflow-safe "if (p->next_action_time <= cur_time) ..." */
|
|
if ((int)(cur_time - p->next_action_time) >= 0) {
|
|
if (p->p_fd == -1) {
|
|
/* Time to send new req */
|
|
trial_cnt++;
|
|
if (send_query_to_peer(p) == 0)
|
|
sent_cnt++;
|
|
} else {
|
|
/* Timed out waiting for reply */
|
|
close(p->p_fd);
|
|
p->p_fd = -1;
|
|
timeout = poll_interval(-1); /* try a bit faster */
|
|
bb_error_msg("timed out waiting for %s, reach 0x%02x, next query in %us",
|
|
p->p_dotted, p->p_reachable_bits, timeout);
|
|
set_next(p, timeout);
|
|
}
|
|
}
|
|
|
|
if (p->next_action_time < nextaction)
|
|
nextaction = p->next_action_time;
|
|
|
|
if (p->p_fd >= 0) {
|
|
/* Wait for reply from this peer */
|
|
pfd[i].fd = p->p_fd;
|
|
pfd[i].events = POLLIN;
|
|
idx2peer[i] = p;
|
|
i++;
|
|
}
|
|
}
|
|
|
|
// if ((trial_cnt > 0 && sent_cnt == 0) || g.peer_cnt == 0) {
|
|
// G.time_was_stepped = 1;
|
|
// }
|
|
|
|
timeout = nextaction - cur_time;
|
|
if (timeout < 1)
|
|
timeout = 1;
|
|
|
|
/* Here we may block */
|
|
VERB2 bb_error_msg("poll %us, sockets:%u", timeout, i);
|
|
nfds = poll(pfd, i, timeout * 1000);
|
|
if (nfds <= 0)
|
|
continue;
|
|
|
|
/* Process any received packets */
|
|
j = 0;
|
|
#if ENABLE_FEATURE_NTPD_SERVER
|
|
if (g.listen_fd != -1) {
|
|
if (pfd[0].revents /* & (POLLIN|POLLERR)*/) {
|
|
nfds--;
|
|
recv_and_process_client_pkt(/*g.listen_fd*/);
|
|
}
|
|
j = 1;
|
|
}
|
|
#endif
|
|
for (; nfds != 0 && j < i; j++) {
|
|
if (pfd[j].revents /* & (POLLIN|POLLERR)*/) {
|
|
nfds--;
|
|
recv_and_process_peer_pkt(idx2peer[j]);
|
|
}
|
|
}
|
|
} /* while (!bb_got_signal) */
|
|
|
|
kill_myself_with_sig(bb_got_signal);
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/*** openntpd-4.6 uses only adjtime, not adjtimex ***/
|
|
|
|
/*** ntp-4.2.6/ntpd/ntp_loopfilter.c - adjtimex usage ***/
|
|
|
|
#if 0
|
|
static double
|
|
direct_freq(double fp_offset)
|
|
{
|
|
|
|
#ifdef KERNEL_PLL
|
|
/*
|
|
* If the kernel is enabled, we need the residual offset to
|
|
* calculate the frequency correction.
|
|
*/
|
|
if (pll_control && kern_enable) {
|
|
memset(&ntv, 0, sizeof(ntv));
|
|
ntp_adjtime(&ntv);
|
|
#ifdef STA_NANO
|
|
clock_offset = ntv.offset / 1e9;
|
|
#else /* STA_NANO */
|
|
clock_offset = ntv.offset / 1e6;
|
|
#endif /* STA_NANO */
|
|
drift_comp = FREQTOD(ntv.freq);
|
|
}
|
|
#endif /* KERNEL_PLL */
|
|
set_freq((fp_offset - clock_offset) / (current_time - clock_epoch) + drift_comp);
|
|
wander_resid = 0;
|
|
return drift_comp;
|
|
}
|
|
|
|
static void
|
|
set_freq(double freq) /* frequency update */
|
|
{
|
|
char tbuf[80];
|
|
|
|
drift_comp = freq;
|
|
|
|
#ifdef KERNEL_PLL
|
|
/*
|
|
* If the kernel is enabled, update the kernel frequency.
|
|
*/
|
|
if (pll_control && kern_enable) {
|
|
memset(&ntv, 0, sizeof(ntv));
|
|
ntv.modes = MOD_FREQUENCY;
|
|
ntv.freq = DTOFREQ(drift_comp);
|
|
ntp_adjtime(&ntv);
|
|
snprintf(tbuf, sizeof(tbuf), "kernel %.3f PPM", drift_comp * 1e6);
|
|
report_event(EVNT_FSET, NULL, tbuf);
|
|
} else {
|
|
snprintf(tbuf, sizeof(tbuf), "ntpd %.3f PPM", drift_comp * 1e6);
|
|
report_event(EVNT_FSET, NULL, tbuf);
|
|
}
|
|
#else /* KERNEL_PLL */
|
|
snprintf(tbuf, sizeof(tbuf), "ntpd %.3f PPM", drift_comp * 1e6);
|
|
report_event(EVNT_FSET, NULL, tbuf);
|
|
#endif /* KERNEL_PLL */
|
|
}
|
|
|
|
...
|
|
...
|
|
...
|
|
|
|
#ifdef KERNEL_PLL
|
|
/*
|
|
* This code segment works when clock adjustments are made using
|
|
* precision time kernel support and the ntp_adjtime() system
|
|
* call. This support is available in Solaris 2.6 and later,
|
|
* Digital Unix 4.0 and later, FreeBSD, Linux and specially
|
|
* modified kernels for HP-UX 9 and Ultrix 4. In the case of the
|
|
* DECstation 5000/240 and Alpha AXP, additional kernel
|
|
* modifications provide a true microsecond clock and nanosecond
|
|
* clock, respectively.
|
|
*
|
|
* Important note: The kernel discipline is used only if the
|
|
* step threshold is less than 0.5 s, as anything higher can
|
|
* lead to overflow problems. This might occur if some misguided
|
|
* lad set the step threshold to something ridiculous.
|
|
*/
|
|
if (pll_control && kern_enable) {
|
|
|
|
#define MOD_BITS (MOD_OFFSET | MOD_MAXERROR | MOD_ESTERROR | MOD_STATUS | MOD_TIMECONST)
|
|
|
|
/*
|
|
* We initialize the structure for the ntp_adjtime()
|
|
* system call. We have to convert everything to
|
|
* microseconds or nanoseconds first. Do not update the
|
|
* system variables if the ext_enable flag is set. In
|
|
* this case, the external clock driver will update the
|
|
* variables, which will be read later by the local
|
|
* clock driver. Afterwards, remember the time and
|
|
* frequency offsets for jitter and stability values and
|
|
* to update the frequency file.
|
|
*/
|
|
memset(&ntv, 0, sizeof(ntv));
|
|
if (ext_enable) {
|
|
ntv.modes = MOD_STATUS;
|
|
} else {
|
|
#ifdef STA_NANO
|
|
ntv.modes = MOD_BITS | MOD_NANO;
|
|
#else /* STA_NANO */
|
|
ntv.modes = MOD_BITS;
|
|
#endif /* STA_NANO */
|
|
if (clock_offset < 0)
|
|
dtemp = -.5;
|
|
else
|
|
dtemp = .5;
|
|
#ifdef STA_NANO
|
|
ntv.offset = (int32)(clock_offset * 1e9 + dtemp);
|
|
ntv.constant = sys_poll;
|
|
#else /* STA_NANO */
|
|
ntv.offset = (int32)(clock_offset * 1e6 + dtemp);
|
|
ntv.constant = sys_poll - 4;
|
|
#endif /* STA_NANO */
|
|
ntv.esterror = (u_int32)(clock_jitter * 1e6);
|
|
ntv.maxerror = (u_int32)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
|
|
ntv.status = STA_PLL;
|
|
|
|
/*
|
|
* Enable/disable the PPS if requested.
|
|
*/
|
|
if (pps_enable) {
|
|
if (!(pll_status & STA_PPSTIME))
|
|
report_event(EVNT_KERN,
|
|
NULL, "PPS enabled");
|
|
ntv.status |= STA_PPSTIME | STA_PPSFREQ;
|
|
} else {
|
|
if (pll_status & STA_PPSTIME)
|
|
report_event(EVNT_KERN,
|
|
NULL, "PPS disabled");
|
|
ntv.status &= ~(STA_PPSTIME |
|
|
STA_PPSFREQ);
|
|
}
|
|
if (sys_leap == LEAP_ADDSECOND)
|
|
ntv.status |= STA_INS;
|
|
else if (sys_leap == LEAP_DELSECOND)
|
|
ntv.status |= STA_DEL;
|
|
}
|
|
|
|
/*
|
|
* Pass the stuff to the kernel. If it squeals, turn off
|
|
* the pps. In any case, fetch the kernel offset,
|
|
* frequency and jitter.
|
|
*/
|
|
if (ntp_adjtime(&ntv) == TIME_ERROR) {
|
|
if (!(ntv.status & STA_PPSSIGNAL))
|
|
report_event(EVNT_KERN, NULL,
|
|
"PPS no signal");
|
|
}
|
|
pll_status = ntv.status;
|
|
#ifdef STA_NANO
|
|
clock_offset = ntv.offset / 1e9;
|
|
#else /* STA_NANO */
|
|
clock_offset = ntv.offset / 1e6;
|
|
#endif /* STA_NANO */
|
|
clock_frequency = FREQTOD(ntv.freq);
|
|
|
|
/*
|
|
* If the kernel PPS is lit, monitor its performance.
|
|
*/
|
|
if (ntv.status & STA_PPSTIME) {
|
|
#ifdef STA_NANO
|
|
clock_jitter = ntv.jitter / 1e9;
|
|
#else /* STA_NANO */
|
|
clock_jitter = ntv.jitter / 1e6;
|
|
#endif /* STA_NANO */
|
|
}
|
|
|
|
#if defined(STA_NANO) && NTP_API == 4
|
|
/*
|
|
* If the TAI changes, update the kernel TAI.
|
|
*/
|
|
if (loop_tai != sys_tai) {
|
|
loop_tai = sys_tai;
|
|
ntv.modes = MOD_TAI;
|
|
ntv.constant = sys_tai;
|
|
ntp_adjtime(&ntv);
|
|
}
|
|
#endif /* STA_NANO */
|
|
}
|
|
#endif /* KERNEL_PLL */
|
|
#endif
|