--- /dev/null
+--- a/include/applets.h
++++ b/include/applets.h
+@@ -285,6 +285,7 @@ IF_NICE(APPLET(nice, _BB_DIR_BIN, _BB_SU
+ IF_NMETER(APPLET(nmeter, _BB_DIR_USR_BIN, _BB_SUID_DROP))
+ IF_NOHUP(APPLET(nohup, _BB_DIR_USR_BIN, _BB_SUID_DROP))
+ IF_NSLOOKUP(APPLET(nslookup, _BB_DIR_USR_BIN, _BB_SUID_DROP))
++IF_NTPD(APPLET(ntpd, _BB_DIR_USR_SBIN, _BB_SUID_DROP))
+ IF_OD(APPLET(od, _BB_DIR_USR_BIN, _BB_SUID_DROP))
+ IF_OPENVT(APPLET(openvt, _BB_DIR_USR_BIN, _BB_SUID_DROP))
+ //IF_PARSE(APPLET(parse, _BB_DIR_USR_BIN, _BB_SUID_DROP))
+--- a/include/usage.h
++++ b/include/usage.h
+@@ -3183,6 +3183,22 @@
+ "Name: debian\n" \
+ "Address: 127.0.0.1\n"
+
++#define ntpd_trivial_usage \
++ "[-dnqNw"IF_FEATURE_NTPD_SERVER("l")"] [-S PROG] [-p PEER]..."
++#define ntpd_full_usage "\n\n" \
++ "NTP client/server\n" \
++ "\nOptions:" \
++ "\n -d Verbose" \
++ "\n -n Do not daemonize" \
++ "\n -q Quit after clock is set" \
++ "\n -N Run at high priority" \
++ "\n -w Do not set time (only query peers), implies -n" \
++ IF_FEATURE_NTPD_SERVER( \
++ "\n -l Run as server on port 123" \
++ ) \
++ "\n -S PROG Run PROG after stepping time, stratum change, and every 11 mins" \
++ "\n -p PEER Obtain time from PEER (may be repeated)"
++
+ #define od_trivial_usage \
+ "[-aBbcDdeFfHhIiLlOovXx] " IF_DESKTOP("[-t TYPE] ") "[FILE]"
+ #define od_full_usage "\n\n" \
+--- a/networking/Config.in
++++ b/networking/Config.in
+@@ -667,6 +667,20 @@ config NSLOOKUP
+ help
+ nslookup is a tool to query Internet name servers.
+
++config NTPD
++ bool "ntpd"
++ default y
++ help
++ The NTP client/server daemon.
++
++config FEATURE_NTPD_SERVER
++ bool "Make ntpd usable as a NTP server"
++ default y
++ depends on NTPD
++ help
++ Make ntpd usable as a NTP server. If you disable this option
++ ntpd will be usable only as a NTP client.
++
+ config PING
+ bool "ping"
+ default n
+--- /dev/null
++++ b/networking/ntpd.c
+@@ -0,0 +1,2262 @@
++/*
++ * NTP client/server, based on OpenNTPD 3.9p1
++ *
++ * Author: Adam Tkac <vonsch@gmail.com>
++ *
++ * Licensed under GPLv2, see file LICENSE in this source tree.
++ *
++ * Parts of OpenNTPD clock syncronization code is replaced by
++ * code which is based on ntp-4.2.6, whuch carries the following
++ * copyright notice:
++ *
++ ***********************************************************************
++ * *
++ * Copyright (c) University of Delaware 1992-2009 *
++ * *
++ * Permission to use, copy, modify, and distribute this software and *
++ * its documentation for any purpose with or without fee is hereby *
++ * granted, provided that the above copyright notice appears in all *
++ * copies and that both the copyright notice and this permission *
++ * notice appear in supporting documentation, and that the name *
++ * University of Delaware not be used in advertising or publicity *
++ * pertaining to distribution of the software without specific, *
++ * written prior permission. The University of Delaware makes no *
++ * representations about the suitability this software for any *
++ * purpose. It is provided "as is" without express or implied *
++ * warranty. *
++ * *
++ ***********************************************************************
++ */
++#include "libbb.h"
++#include <math.h>
++#include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
++#include <sys/timex.h>
++#ifndef IPTOS_LOWDELAY
++# define IPTOS_LOWDELAY 0x10
++#endif
++#ifndef IP_PKTINFO
++# error "Sorry, your kernel has to support IP_PKTINFO"
++#endif
++
++
++/* Verbosity control (max level of -dddd options accepted).
++ * max 5 is very talkative (and bloated). 2 is non-bloated,
++ * production level setting.
++ */
++#define MAX_VERBOSE 2
++
++
++/* High-level description of the algorithm:
++ *
++ * We start running with very small poll_exp, BURSTPOLL,
++ * in order to quickly accumulate INITIAL_SAMPLES datapoints
++ * for each peer. Then, time is stepped if the offset is larger
++ * than STEP_THRESHOLD, otherwise it isn't; anyway, we enlarge
++ * poll_exp to MINPOLL and enter frequency measurement step:
++ * we collect new datapoints but ignore them for WATCH_THRESHOLD
++ * seconds. After WATCH_THRESHOLD seconds we look at accumulated
++ * offset and estimate frequency drift.
++ *
++ * (frequency measurement step seems to not be strictly needed,
++ * it is conditionally disabled with USING_INITIAL_FREQ_ESTIMATION
++ * define set to 0)
++ *
++ * After this, we enter "steady state": we collect a datapoint,
++ * we select the best peer, if this datapoint is not a new one
++ * (IOW: if this datapoint isn't for selected peer), sleep
++ * and collect another one; otherwise, use its offset to update
++ * frequency drift, if offset is somewhat large, reduce poll_exp,
++ * otherwise increase poll_exp.
++ *
++ * If offset is larger than STEP_THRESHOLD, which shouldn't normally
++ * happen, we assume that something "bad" happened (computer
++ * was hibernated, someone set totally wrong date, etc),
++ * then the time is stepped, all datapoints are discarded,
++ * and we go back to steady state.
++ */
++
++#define RETRY_INTERVAL 5 /* on error, retry in N secs */
++#define RESPONSE_INTERVAL 15 /* wait for reply up to N secs */
++#define INITIAL_SAMPLES 4 /* how many samples do we want for init */
++
++/* Clock discipline parameters and constants */
++
++/* Step threshold (sec). std ntpd uses 0.128.
++ * Using exact power of 2 (1/8) results in smaller code */
++#define STEP_THRESHOLD 0.125
++#define WATCH_THRESHOLD 128 /* stepout threshold (sec). std ntpd uses 900 (11 mins (!)) */
++/* NB: set WATCH_THRESHOLD to ~60 when debugging to save time) */
++//UNUSED: #define PANIC_THRESHOLD 1000 /* panic threshold (sec) */
++
++#define FREQ_TOLERANCE 0.000015 /* frequency tolerance (15 PPM) */
++#define BURSTPOLL 0 /* initial poll */
++#define MINPOLL 5 /* minimum poll interval. std ntpd uses 6 (6: 64 sec) */
++#define BIGPOLL 10 /* drop to lower poll at any trouble (10: 17 min) */
++#define MAXPOLL 12 /* maximum poll interval (12: 1.1h, 17: 36.4h). std ntpd uses 17 */
++/* Actively lower poll when we see such big offsets.
++ * With STEP_THRESHOLD = 0.125, it means we try to sync more aggressively
++ * if offset increases over 0.03 sec */
++#define POLLDOWN_OFFSET (STEP_THRESHOLD / 4)
++#define MINDISP 0.01 /* minimum dispersion (sec) */
++#define MAXDISP 16 /* maximum dispersion (sec) */
++#define MAXSTRAT 16 /* maximum stratum (infinity metric) */
++#define MAXDIST 1 /* distance threshold (sec) */
++#define MIN_SELECTED 1 /* minimum intersection survivors */
++#define MIN_CLUSTERED 3 /* minimum cluster survivors */
++
++#define MAXDRIFT 0.000500 /* frequency drift we can correct (500 PPM) */
++
++/* Poll-adjust threshold.
++ * When we see that offset is small enough compared to discipline jitter,
++ * we grow a counter: += MINPOLL. When it goes over POLLADJ_LIMIT,
++ * we poll_exp++. If offset isn't small, counter -= poll_exp*2,
++ * and when it goes below -POLLADJ_LIMIT, we poll_exp--
++ * (bumped from 30 to 36 since otherwise I often see poll_exp going *2* steps down)
++ */
++#define POLLADJ_LIMIT 36
++/* If offset < POLLADJ_GATE * discipline_jitter, then we can increase
++ * poll interval (we think we can't improve timekeeping
++ * by staying at smaller poll).
++ */
++#define POLLADJ_GATE 4
++/* Compromise Allan intercept (sec). doc uses 1500, std ntpd uses 512 */
++#define ALLAN 512
++/* PLL loop gain */
++#define PLL 65536
++/* FLL loop gain [why it depends on MAXPOLL??] */
++#define FLL (MAXPOLL + 1)
++/* Parameter averaging constant */
++#define AVG 4
++
++
++enum {
++ NTP_VERSION = 4,
++ NTP_MAXSTRATUM = 15,
++
++ NTP_DIGESTSIZE = 16,
++ NTP_MSGSIZE_NOAUTH = 48,
++ NTP_MSGSIZE = (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE),
++
++ /* Status Masks */
++ MODE_MASK = (7 << 0),
++ VERSION_MASK = (7 << 3),
++ VERSION_SHIFT = 3,
++ LI_MASK = (3 << 6),
++
++ /* Leap Second Codes (high order two bits of m_status) */
++ LI_NOWARNING = (0 << 6), /* no warning */
++ LI_PLUSSEC = (1 << 6), /* add a second (61 seconds) */
++ LI_MINUSSEC = (2 << 6), /* minus a second (59 seconds) */
++ LI_ALARM = (3 << 6), /* alarm condition */
++
++ /* Mode values */
++ MODE_RES0 = 0, /* reserved */
++ MODE_SYM_ACT = 1, /* symmetric active */
++ MODE_SYM_PAS = 2, /* symmetric passive */
++ MODE_CLIENT = 3, /* client */
++ MODE_SERVER = 4, /* server */
++ MODE_BROADCAST = 5, /* broadcast */
++ MODE_RES1 = 6, /* reserved for NTP control message */
++ MODE_RES2 = 7, /* reserved for private use */
++};
++
++//TODO: better base selection
++#define OFFSET_1900_1970 2208988800UL /* 1970 - 1900 in seconds */
++
++#define NUM_DATAPOINTS 8
++
++typedef struct {
++ uint32_t int_partl;
++ uint32_t fractionl;
++} l_fixedpt_t;
++
++typedef struct {
++ uint16_t int_parts;
++ uint16_t fractions;
++} s_fixedpt_t;
++
++typedef struct {
++ uint8_t m_status; /* status of local clock and leap info */
++ uint8_t m_stratum;
++ uint8_t m_ppoll; /* poll value */
++ int8_t m_precision_exp;
++ s_fixedpt_t m_rootdelay;
++ s_fixedpt_t m_rootdisp;
++ uint32_t m_refid;
++ l_fixedpt_t m_reftime;
++ l_fixedpt_t m_orgtime;
++ l_fixedpt_t m_rectime;
++ l_fixedpt_t m_xmttime;
++ uint32_t m_keyid;
++ uint8_t m_digest[NTP_DIGESTSIZE];
++} msg_t;
++
++typedef struct {
++ double d_recv_time;
++ double d_offset;
++ double d_dispersion;
++} datapoint_t;
++
++typedef struct {
++ len_and_sockaddr *p_lsa;
++ char *p_dotted;
++ /* when to send new query (if p_fd == -1)
++ * or when receive times out (if p_fd >= 0): */
++ int p_fd;
++ int datapoint_idx;
++ uint32_t lastpkt_refid;
++ uint8_t lastpkt_status;
++ uint8_t lastpkt_stratum;
++ uint8_t reachable_bits;
++ double next_action_time;
++ double p_xmttime;
++ double lastpkt_recv_time;
++ double lastpkt_delay;
++ double lastpkt_rootdelay;
++ double lastpkt_rootdisp;
++ /* produced by filter algorithm: */
++ double filter_offset;
++ double filter_dispersion;
++ double filter_jitter;
++ datapoint_t filter_datapoint[NUM_DATAPOINTS];
++ /* last sent packet: */
++ msg_t p_xmt_msg;
++} peer_t;
++
++
++#define USING_KERNEL_PLL_LOOP 1
++#define USING_INITIAL_FREQ_ESTIMATION 0
++
++enum {
++ OPT_n = (1 << 0),
++ OPT_q = (1 << 1),
++ OPT_N = (1 << 2),
++ OPT_x = (1 << 3),
++ /* Insert new options above this line. */
++ /* Non-compat options: */
++ OPT_w = (1 << 4),
++ OPT_p = (1 << 5),
++ OPT_S = (1 << 6),
++ OPT_l = (1 << 7) * ENABLE_FEATURE_NTPD_SERVER,
++};
++
++struct globals {
++ double cur_time;
++ /* total round trip delay to currently selected reference clock */
++ double rootdelay;
++ /* reference timestamp: time when the system clock was last set or corrected */
++ double reftime;
++ /* total dispersion to currently selected reference clock */
++ double rootdisp;
++
++ double last_script_run;
++ char *script_name;
++ llist_t *ntp_peers;
++#if ENABLE_FEATURE_NTPD_SERVER
++ int listen_fd;
++#endif
++ unsigned verbose;
++ unsigned peer_cnt;
++ /* refid: 32-bit code identifying the particular server or reference clock
++ * in stratum 0 packets this is a four-character ASCII string,
++ * called the kiss code, used for debugging and monitoring
++ * in stratum 1 packets this is a four-character ASCII string
++ * assigned to the reference clock by IANA. Example: "GPS "
++ * in stratum 2+ packets, it's IPv4 address or 4 first bytes of MD5 hash of IPv6
++ */
++ uint32_t refid;
++ uint8_t ntp_status;
++ /* precision is defined as the larger of the resolution and time to
++ * read the clock, in log2 units. For instance, the precision of a
++ * mains-frequency clock incrementing at 60 Hz is 16 ms, even when the
++ * system clock hardware representation is to the nanosecond.
++ *
++ * Delays, jitters of various kinds are clamper down to precision.
++ *
++ * If precision_sec is too large, discipline_jitter gets clamped to it
++ * and if offset is much smaller than discipline_jitter, poll interval
++ * grows even though we really can benefit from staying at smaller one,
++ * collecting non-lagged datapoits and correcting the offset.
++ * (Lagged datapoits exist when poll_exp is large but we still have
++ * systematic offset error - the time distance between datapoints
++ * is significat and older datapoints have smaller offsets.
++ * This makes our offset estimation a bit smaller than reality)
++ * Due to this effect, setting G_precision_sec close to
++ * STEP_THRESHOLD isn't such a good idea - offsets may grow
++ * too big and we will step. I observed it with -6.
++ *
++ * OTOH, setting precision too small would result in futile attempts
++ * to syncronize to the unachievable precision.
++ *
++ * -6 is 1/64 sec, -7 is 1/128 sec and so on.
++ */
++#define G_precision_exp -8
++#define G_precision_sec (1.0 / (1 << (- G_precision_exp)))
++ uint8_t stratum;
++ /* Bool. After set to 1, never goes back to 0: */
++ smallint initial_poll_complete;
++
++#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) */
++ uint8_t discipline_state; // doc calls it c.state
++ uint8_t poll_exp; // s.poll
++ int polladj_count; // c.count
++ long kernel_freq_drift;
++ peer_t *last_update_peer;
++ double last_update_offset; // c.last
++ double last_update_recv_time; // s.t
++ double discipline_jitter; // c.jitter
++ //double cluster_offset; // s.offset
++ //double cluster_jitter; // s.jitter
++#if !USING_KERNEL_PLL_LOOP
++ double discipline_freq_drift; // c.freq
++ /* Maybe conditionally calculate wander? it's used only for logging */
++ double discipline_wander; // c.wander
++#endif
++};
++#define G (*ptr_to_globals)
++
++static const int const_IPTOS_LOWDELAY = IPTOS_LOWDELAY;
++
++
++#define VERB1 if (MAX_VERBOSE && G.verbose)
++#define VERB2 if (MAX_VERBOSE >= 2 && G.verbose >= 2)
++#define VERB3 if (MAX_VERBOSE >= 3 && G.verbose >= 3)
++#define VERB4 if (MAX_VERBOSE >= 4 && G.verbose >= 4)
++#define VERB5 if (MAX_VERBOSE >= 5 && G.verbose >= 5)
++
++
++static double LOG2D(int a)
++{
++ if (a < 0)
++ return 1.0 / (1UL << -a);
++ return 1UL << a;
++}
++static ALWAYS_INLINE double SQUARE(double x)
++{
++ return x * x;
++}
++static ALWAYS_INLINE double MAXD(double a, double b)
++{
++ if (a > b)
++ return a;
++ return b;
++}
++static ALWAYS_INLINE double MIND(double a, double b)
++{
++ if (a < b)
++ return a;
++ return b;
++}
++static NOINLINE double my_SQRT(double X)
++{
++ union {
++ float f;
++ int32_t i;
++ } v;
++ double invsqrt;
++ double Xhalf = X * 0.5;
++
++ /* Fast and good approximation to 1/sqrt(X), black magic */
++ v.f = X;
++ /*v.i = 0x5f3759df - (v.i >> 1);*/
++ v.i = 0x5f375a86 - (v.i >> 1); /* - this constant is slightly better */
++ invsqrt = v.f; /* better than 0.2% accuracy */
++
++ /* Refining it using Newton's method: x1 = x0 - f(x0)/f'(x0)
++ * f(x) = 1/(x*x) - X (f==0 when x = 1/sqrt(X))
++ * f'(x) = -2/(x*x*x)
++ * f(x)/f'(x) = (X - 1/(x*x)) / (2/(x*x*x)) = X*x*x*x/2 - x/2
++ * x1 = x0 - (X*x0*x0*x0/2 - x0/2) = 1.5*x0 - X*x0*x0*x0/2 = x0*(1.5 - (X/2)*x0*x0)
++ */
++ invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); /* ~0.05% accuracy */
++ /* invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); 2nd iter: ~0.0001% accuracy */
++ /* With 4 iterations, more than half results will be exact,
++ * at 6th iterations result stabilizes with about 72% results exact.
++ * We are well satisfied with 0.05% accuracy.
++ */
++
++ return X * invsqrt; /* X * 1/sqrt(X) ~= sqrt(X) */
++}
++static ALWAYS_INLINE double SQRT(double X)
++{
++ /* If this arch doesn't use IEEE 754 floats, fall back to using libm */
++ if (sizeof(float) != 4)
++ return sqrt(X);
++
++ /* This avoids needing libm, saves about 0.5k on x86-32 */
++ return my_SQRT(X);
++}
++
++static double
++gettime1900d(void)
++{
++ struct timeval tv;
++ gettimeofday(&tv, NULL); /* never fails */
++ G.cur_time = tv.tv_sec + (1.0e-6 * tv.tv_usec) + OFFSET_1900_1970;
++ return G.cur_time;
++}
++
++static void
++d_to_tv(double d, struct timeval *tv)
++{
++ tv->tv_sec = (long)d;
++ tv->tv_usec = (d - tv->tv_sec) * 1000000;
++}
++
++static double
++lfp_to_d(l_fixedpt_t lfp)
++{
++ double ret;
++ lfp.int_partl = ntohl(lfp.int_partl);
++ lfp.fractionl = ntohl(lfp.fractionl);
++ ret = (double)lfp.int_partl + ((double)lfp.fractionl / UINT_MAX);
++ return ret;
++}
++static double
++sfp_to_d(s_fixedpt_t sfp)
++{
++ double ret;
++ sfp.int_parts = ntohs(sfp.int_parts);
++ sfp.fractions = ntohs(sfp.fractions);
++ ret = (double)sfp.int_parts + ((double)sfp.fractions / USHRT_MAX);
++ return ret;
++}
++#if ENABLE_FEATURE_NTPD_SERVER
++static l_fixedpt_t
++d_to_lfp(double d)
++{
++ l_fixedpt_t lfp;
++ lfp.int_partl = (uint32_t)d;
++ lfp.fractionl = (uint32_t)((d - lfp.int_partl) * UINT_MAX);
++ lfp.int_partl = htonl(lfp.int_partl);
++ lfp.fractionl = htonl(lfp.fractionl);
++ return lfp;
++}
++static s_fixedpt_t
++d_to_sfp(double d)
++{
++ s_fixedpt_t sfp;
++ sfp.int_parts = (uint16_t)d;
++ sfp.fractions = (uint16_t)((d - sfp.int_parts) * USHRT_MAX);
++ sfp.int_parts = htons(sfp.int_parts);
++ sfp.fractions = htons(sfp.fractions);
++ return sfp;
++}
++#endif
++
++static double
++dispersion(const datapoint_t *dp)
++{
++ return dp->d_dispersion + FREQ_TOLERANCE * (G.cur_time - dp->d_recv_time);
++}
++
++static double
++root_distance(peer_t *p)
++{
++ /* The root synchronization distance is the maximum error due to
++ * all causes of the local clock relative to the primary server.
++ * It is defined as half the total delay plus total dispersion
++ * plus peer jitter.
++ */
++ return MAXD(MINDISP, p->lastpkt_rootdelay + p->lastpkt_delay) / 2
++ + p->lastpkt_rootdisp
++ + p->filter_dispersion
++ + FREQ_TOLERANCE * (G.cur_time - p->lastpkt_recv_time)
++ + p->filter_jitter;
++}
++
++static void
++set_next(peer_t *p, unsigned t)
++{
++ p->next_action_time = G.cur_time + t;
++}
++
++/*
++ * Peer clock filter and its helpers
++ */
++static void
++filter_datapoints(peer_t *p)
++{
++ int i, idx;
++ int got_newest;
++ double minoff, maxoff, wavg, sum, w;
++ double x = x; /* for compiler */
++ double oldest_off = oldest_off;
++ double oldest_age = oldest_age;
++ double newest_off = newest_off;
++ double newest_age = newest_age;
++
++ minoff = maxoff = p->filter_datapoint[0].d_offset;
++ for (i = 1; i < NUM_DATAPOINTS; i++) {
++ if (minoff > p->filter_datapoint[i].d_offset)
++ minoff = p->filter_datapoint[i].d_offset;
++ if (maxoff < p->filter_datapoint[i].d_offset)
++ maxoff = p->filter_datapoint[i].d_offset;
++ }
++
++ idx = p->datapoint_idx; /* most recent datapoint */
++ /* Average offset:
++ * Drop two outliers and take weighted average of the rest:
++ * most_recent/2 + older1/4 + older2/8 ... + older5/32 + older6/32
++ * we use older6/32, not older6/64 since sum of weights should be 1:
++ * 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/32 = 1
++ */
++ wavg = 0;
++ w = 0.5;
++ /* n-1
++ * --- dispersion(i)
++ * filter_dispersion = \ -------------
++ * / (i+1)
++ * --- 2
++ * i=0
++ */
++ got_newest = 0;
++ sum = 0;
++ for (i = 0; i < NUM_DATAPOINTS; i++) {
++ VERB4 {
++ bb_error_msg("datapoint[%d]: off:%f disp:%f(%f) age:%f%s",
++ i,
++ p->filter_datapoint[idx].d_offset,
++ p->filter_datapoint[idx].d_dispersion, dispersion(&p->filter_datapoint[idx]),
++ G.cur_time - p->filter_datapoint[idx].d_recv_time,
++ (minoff == p->filter_datapoint[idx].d_offset || maxoff == p->filter_datapoint[idx].d_offset)
++ ? " (outlier by offset)" : ""
++ );
++ }
++
++ sum += dispersion(&p->filter_datapoint[idx]) / (2 << i);
++
++ if (minoff == p->filter_datapoint[idx].d_offset) {
++ minoff -= 1; /* so that we don't match it ever again */
++ } else
++ if (maxoff == p->filter_datapoint[idx].d_offset) {
++ maxoff += 1;
++ } else {
++ oldest_off = p->filter_datapoint[idx].d_offset;
++ oldest_age = G.cur_time - p->filter_datapoint[idx].d_recv_time;
++ if (!got_newest) {
++ got_newest = 1;
++ newest_off = oldest_off;
++ newest_age = oldest_age;
++ }
++ x = oldest_off * w;
++ wavg += x;
++ w /= 2;
++ }
++
++ idx = (idx - 1) & (NUM_DATAPOINTS - 1);
++ }
++ p->filter_dispersion = sum;
++ wavg += x; /* add another older6/64 to form older6/32 */
++ /* Fix systematic underestimation with large poll intervals.
++ * Imagine that we still have a bit of uncorrected drift,
++ * and poll interval is big (say, 100 sec). Offsets form a progression:
++ * 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 - 0.7 is most recent.
++ * The algorithm above drops 0.0 and 0.7 as outliers,
++ * and then we have this estimation, ~25% off from 0.7:
++ * 0.1/32 + 0.2/32 + 0.3/16 + 0.4/8 + 0.5/4 + 0.6/2 = 0.503125
++ */
++ x = oldest_age - newest_age;
++ if (x != 0) {
++ x = newest_age / x; /* in above example, 100 / (600 - 100) */
++ if (x < 1) { /* paranoia check */
++ x = (newest_off - oldest_off) * x; /* 0.5 * 100/500 = 0.1 */
++ wavg += x;
++ }
++ }
++ p->filter_offset = wavg;
++
++ /* +----- -----+ ^ 1/2
++ * | n-1 |
++ * | --- |
++ * | 1 \ 2 |
++ * filter_jitter = | --- * / (avg-offset_j) |
++ * | n --- |
++ * | j=0 |
++ * +----- -----+
++ * where n is the number of valid datapoints in the filter (n > 1);
++ * if filter_jitter < precision then filter_jitter = precision
++ */
++ sum = 0;
++ for (i = 0; i < NUM_DATAPOINTS; i++) {
++ sum += SQUARE(wavg - p->filter_datapoint[i].d_offset);
++ }
++ sum = SQRT(sum / NUM_DATAPOINTS);
++ p->filter_jitter = sum > G_precision_sec ? sum : G_precision_sec;
++
++ VERB3 bb_error_msg("filter offset:%f(corr:%e) disp:%f jitter:%f",
++ p->filter_offset, x,
++ p->filter_dispersion,
++ p->filter_jitter);
++}
++
++static void
++reset_peer_stats(peer_t *p, double offset)
++{
++ int i;
++ bool small_ofs = fabs(offset) < 16 * STEP_THRESHOLD;
++
++ for (i = 0; i < NUM_DATAPOINTS; i++) {
++ if (small_ofs) {
++ 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 = G.cur_time;
++ p->filter_datapoint[i].d_offset = 0;
++ p->filter_datapoint[i].d_dispersion = MAXDISP;
++ }
++ }
++ if (small_ofs) {
++ p->lastpkt_recv_time += offset;
++ } else {
++ p->reachable_bits = 0;
++ p->lastpkt_recv_time = G.cur_time;
++ }
++ filter_datapoints(p); /* recalc p->filter_xxx */
++ 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 = G.cur_time; /* = set_next(p, 0); */
++ reset_peer_stats(p, 16 * STEP_THRESHOLD);
++
++ 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 void
++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;
++ }
++
++ p->reachable_bits <<= 1;
++ VERB1 bb_error_msg("sent query to %s", p->p_dotted);
++ set_next(p, RESPONSE_INTERVAL);
++}
++
++
++/* Note that there is no provision to prevent several run_scripts
++ * to be done in quick succession. In fact, it happens rather often
++ * if initial syncronization results in a step.
++ * You will see "step" and then "stratum" script runs, sometimes
++ * as close as only 0.002 seconds apart.
++ * Script should be ready to deal with this.
++ */
++static void run_script(const char *action, double offset)
++{
++ char *argv[3];
++ char *env1, *env2, *env3, *env4;
++
++ if (!G.script_name)
++ return;
++
++ argv[0] = (char*) G.script_name;
++ argv[1] = (char*) action;
++ argv[2] = NULL;
++
++ VERB1 bb_error_msg("executing '%s %s'", G.script_name, action);
++
++ env1 = xasprintf("%s=%u", "stratum", G.stratum);
++ putenv(env1);
++ env2 = xasprintf("%s=%ld", "freq_drift_ppm", G.kernel_freq_drift);
++ putenv(env2);
++ env3 = xasprintf("%s=%u", "poll_interval", 1 << G.poll_exp);
++ putenv(env3);
++ env4 = xasprintf("%s=%f", "offset", offset);
++ putenv(env4);
++ /* Other items of potential interest: selected peer,
++ * rootdelay, reftime, rootdisp, refid, ntp_status,
++ * last_update_offset, last_update_recv_time, discipline_jitter,
++ * how many peers have reachable_bits = 0?
++ */
++
++ /* Don't want to wait: it may run hwclock --systohc, and that
++ * may take some time (seconds): */
++ /*spawn_and_wait(argv);*/
++ spawn(argv);
++
++ unsetenv("stratum");
++ unsetenv("freq_drift_ppm");
++ unsetenv("poll_interval");
++ unsetenv("offset");
++ free(env1);
++ free(env2);
++ free(env3);
++ free(env4);
++
++ G.last_script_run = G.cur_time;
++}
++
++static NOINLINE void
++step_time(double offset)
++{
++ llist_t *item;
++ 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);
++
++ /* Correct various fields which contain time-relative values: */
++
++ /* p->lastpkt_recv_time, p->next_action_time and such: */
++ for (item = G.ntp_peers; item != NULL; item = item->link) {
++ peer_t *pp = (peer_t *) item->data;
++ reset_peer_stats(pp, offset);
++ //bb_error_msg("offset:%f pp->next_action_time:%f -> %f",
++ // offset, pp->next_action_time, pp->next_action_time + offset);
++ pp->next_action_time += offset;
++ }
++ /* Globals: */
++ G.cur_time += offset;
++ G.last_update_recv_time += offset;
++ G.last_script_run += offset;
++}
++
++
++/*
++ * Selection and clustering, and their helpers
++ */
++typedef struct {
++ peer_t *p;
++ int type;
++ double edge;
++ double opt_rd; /* optimization */
++} 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->reachable_bits & (p->reachable_bits-1)) == 0) {
++ /* One or zero bits in reachable_bits */
++ VERB3 bb_error_msg("peer %s unfit for selection: unreachable", p->p_dotted);
++ return 0;
++ }
++#if 0 /* we filter out such packets earlier */
++ if ((p->lastpkt_status & 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;
++ }
++#endif
++ /* rd is root_distance(p) */
++ 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(void)
++{
++ peer_t *p;
++ 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;
++ if (G.initial_poll_complete) while (item != NULL) {
++ double rd, offset;
++
++ p = (peer_t *) item->data;
++ rd = root_distance(p);
++ 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;
++ point[num_points].opt_rd = rd;
++ num_points++;
++ point[num_points].p = p;
++ point[num_points].type = 0;
++ point[num_points].edge = offset;
++ point[num_points].opt_rd = rd;
++ num_points++;
++ point[num_points].p = p;
++ point[num_points].type = 1;
++ point[num_points].edge = offset + rd;
++ point[num_points].opt_rd = 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;
++ }
++//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++) {
++ if (point[i].edge < low || point[i].edge > high)
++ continue;
++ p = point[i].p;
++ survivor[num_survivors].p = p;
++ /* x.opt_rd == root_distance(p); */
++ survivor[num_survivors].metric = MAXDIST * p->lastpkt_stratum + point[i].opt_rd;
++ 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) {
++ VERB3 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;
++
++ 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;
++ 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 / num_survivors);
++ 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++;
++ }
++ }
++
++ if (0) {
++ /* Combine the offsets of the clustering algorithm survivors
++ * using a weighted average with weight determined by the root
++ * distance. Compute the selection jitter as the weighted RMS
++ * difference between the first survivor and the remaining
++ * survivors. In some cases the inherent clock jitter can be
++ * reduced by not using this algorithm, especially when frequent
++ * clockhopping is involved. bbox: thus we don't do it.
++ */
++ double x, y, z, w;
++ y = z = w = 0;
++ for (i = 0; i < num_survivors; i++) {
++ p = survivor[i].p;
++ x = root_distance(p);
++ y += 1 / x;
++ z += p->filter_offset / x;
++ w += SQUARE(p->filter_offset - survivor[0].p->filter_offset) / x;
++ }
++ //G.cluster_offset = z / y;
++ //G.cluster_jitter = SQRT(w / y);
++ }
++
++ /* 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.
++ */
++ p = survivor[0].p;
++ if (G.last_update_peer
++ && G.last_update_peer->lastpkt_stratum <= p->lastpkt_stratum
++ ) {
++ /* Starting from 1 is ok here */
++ for (i = 1; i < num_survivors; i++) {
++ if (G.last_update_peer == survivor[i].p) {
++ VERB4 bb_error_msg("keeping old synced peer");
++ p = G.last_update_peer;
++ goto keep_old;
++ }
++ }
++ }
++ G.last_update_peer = p;
++ keep_old:
++ VERB3 bb_error_msg("selected peer %s filter_offset:%f age:%f",
++ p->p_dotted,
++ p->filter_offset,
++ G.cur_time - p->lastpkt_recv_time
++ );
++ return 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 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;
++}
++/* Return: -1: decrease poll interval, 0: leave as is, 1: increase */
++static NOINLINE int
++update_local_clock(peer_t *p)
++{
++ int rc;
++ struct timex tmx;
++ /* Note: can use G.cluster_offset instead: */
++ double offset = p->filter_offset;
++ double recv_time = p->lastpkt_recv_time;
++ double abs_offset;
++#if !USING_KERNEL_PLL_LOOP
++ double freq_drift;
++#endif
++ double since_last_update;
++ double etemp, dtemp;
++
++ abs_offset = fabs(offset);
++
++#if 0
++ /* If needed, -S script can do it by looking at $offset
++ * env var and killing parent */
++ /* 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);
++ }
++#endif
++
++ /* 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;
++#if !USING_KERNEL_PLL_LOOP
++ freq_drift = 0;
++#endif
++#if USING_INITIAL_FREQ_ESTIMATION
++ 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" */
++ }
++# if !USING_KERNEL_PLL_LOOP
++ freq_drift = (offset - G.last_update_offset) / since_last_update;
++# endif
++ }
++#endif
++
++ /* There are two main regimes: when the
++ * offset exceeds the step threshold and when it does not.
++ */
++ if (abs_offset > STEP_THRESHOLD) {
++ 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;
++
++ run_script("step", offset);
++
++#if USING_INITIAL_FREQ_ESTIMATION
++ if (G.discipline_state == STATE_NSET) {
++ set_new_values(STATE_FREQ, /*offset:*/ 0, recv_time);
++ return 1; /* "ok to increase poll interval" */
++ }
++#endif
++ set_new_values(STATE_SYNC, /*offset:*/ 0, recv_time);
++
++ } else { /* abs_offset <= STEP_THRESHOLD */
++
++ if (G.poll_exp < MINPOLL && G.initial_poll_complete) {
++ VERB3 bb_error_msg("small offset:%f, disabling burst mode", offset);
++ G.polladj_count = 0;
++ 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);
++ }
++#if USING_INITIAL_FREQ_ESTIMATION
++ /* 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);
++#else
++ set_new_values(STATE_SYNC, offset, recv_time);
++#endif
++ VERB3 bb_error_msg("transitioning to FREQ, datapoint ignored");
++ return 0; /* "leave poll interval as is" */
++
++#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
++
++#if USING_INITIAL_FREQ_ESTIMATION
++ 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;
++#endif
++
++ default:
++#if !USING_KERNEL_PLL_LOOP
++ /* 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);
++#endif
++ set_new_values(STATE_SYNC, offset, recv_time);
++ break;
++ }
++ if (G.stratum != p->lastpkt_stratum + 1) {
++ G.stratum = p->lastpkt_stratum + 1;
++ run_script("stratum", offset);
++ }
++ }
++
++ G.reftime = G.cur_time;
++ G.ntp_status = p->lastpkt_status;
++ G.refid = p->lastpkt_refid;
++ G.rootdelay = p->lastpkt_rootdelay + p->lastpkt_delay;
++ dtemp = p->filter_jitter; // SQRT(SQUARE(p->filter_jitter) + SQUARE(G.cluster_jitter));
++ dtemp += MAXD(p->filter_dispersion + FREQ_TOLERANCE * (G.cur_time - 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);
++ }
++
++ 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 */
++ tmx.status = STA_PLL;
++ if (G.ntp_status & LI_PLUSSEC)
++ tmx.status |= STA_INS;
++ if (G.ntp_status & LI_MINUSSEC)
++ 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);
++ rc = adjtimex(&tmx);
++ if (rc < 0)
++ bb_perror_msg_and_die("adjtimex");
++ /* NB: here kernel returns constant == G.poll_exp, not == G.poll_exp - 4.
++ * Not sure why. Perhaps it is normal.
++ */
++ 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
++ VERB3 {
++ /* 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
++ G.kernel_freq_drift = tmx.freq / 65536;
++ VERB2 bb_error_msg("update peer:%s, offset:%f, clock drift:%ld ppm",
++ p->p_dotted, G.last_update_offset, G.kernel_freq_drift);
++
++ 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)
++{
++ unsigned interval, r;
++ exponent = G.poll_exp + exponent;
++ if (exponent < 0)
++ exponent = 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 NOINLINE 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?
++ interval = retry_interval();
++ goto set_next_and_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 set_next_and_close_sock;
++ }
++
++// /* 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_status = msg.m_status;
++ p->lastpkt_stratum = msg.m_stratum;
++ 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 = G.cur_time;
++
++ 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->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);
++ if (p->lastpkt_delay < G_precision_sec)
++ p->lastpkt_delay = G_precision_sec;
++ datapoint->d_dispersion = LOG2D(msg.m_precision_exp) + G_precision_sec;
++ if (!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->reachable_bits |= 1;
++ if ((MAX_VERBOSE && G.verbose) || (option_mask32 & OPT_w)) {
++ bb_error_msg("reply from %s: reach 0x%02x offset %f delay %f status 0x%02x strat %d refid 0x%08x rootdelay %f",
++ p->p_dotted,
++ p->reachable_bits,
++ datapoint->d_offset,
++ p->lastpkt_delay,
++ p->lastpkt_status,
++ p->lastpkt_stratum,
++ p->lastpkt_refid,
++ p->lastpkt_rootdelay
++ /* not shown: m_ppoll, m_precision_exp, m_rootdisp,
++ * m_reftime, m_orgtime, m_rectime, m_xmttime
++ */
++ );
++ }
++
++ /* Muck with statictics and update the clock */
++ filter_datapoints(p);
++ q = select_and_cluster();
++ rc = -1;
++ if (q) {
++ rc = 0;
++ if (!(option_mask32 & OPT_w)) {
++ rc = update_local_clock(q);
++ /* If drift is dangerously large, immediately
++ * drop poll interval one step down.
++ */
++ if (fabs(q->filter_offset) >= POLLDOWN_OFFSET) {
++ VERB3 bb_error_msg("offset:%f > POLLDOWN_OFFSET", q->filter_offset);
++ goto poll_down;
++ }
++ }
++ }
++ /* else: no peer selected, rc = -1: we want to poll more often */
++
++ 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.poll_exp >= BIGPOLL) {
++ poll_down:
++ G.polladj_count = 0;
++ if (G.poll_exp > MINPOLL) {
++ llist_t *item;
++
++ G.poll_exp--;
++ /* Correct p->next_action_time in each peer
++ * which waits for sending, so that they send earlier.
++ * Old pp->next_action_time are on the order
++ * of t + (1 << old_poll_exp) + small_random,
++ * we simply need to subtract ~half of that.
++ */
++ for (item = G.ntp_peers; item != NULL; item = item->link) {
++ peer_t *pp = (peer_t *) item->data;
++ if (pp->p_fd < 0)
++ pp->next_action_time -= (1 << 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_and_close_sock:
++ set_next(p, interval);
++ /* 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 NOINLINE void
++recv_and_process_client_pkt(void /*int fd*/)
++{
++ ssize_t size;
++ uint8_t version;
++ 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.ntp_status : 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;
++ /* this time was obtained between poll() and recv() */
++ msg.m_rectime = d_to_lfp(G.cur_time);
++ msg.m_xmttime = d_to_lfp(gettime1900d()); /* this instant */
++ if (G.peer_cnt == 0) {
++ /* we have no peers: "stratum 1 server" mode. reftime = our own time */
++ G.reftime = G.cur_time;
++ }
++ 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("you must be root");
++
++ /* Set some globals */
++ G.stratum = MAXSTRAT;
++ if (BURSTPOLL != 0)
++ G.poll_exp = BURSTPOLL; /* speeds up initial sync */
++ G.last_script_run = G.reftime = G.last_update_recv_time = gettime1900d(); /* sets G.cur_time too */
++
++ /* Parse options */
++ peers = NULL;
++ opt_complementary = "dd:p::wn"; /* d: counter; p: list; -w implies -n */
++ opts = getopt32(argv,
++ "nqNx" /* compat */
++ "wp:S:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
++ "d" /* compat */
++ "46aAbgL", /* compat, ignored */
++ &peers, &G.script_name, &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;
++ if (peers) {
++ while (peers)
++ add_peers(llist_pop(&peers));
++ } else {
++ /* -l but no peers: "stratum 1 server" mode */
++ G.stratum = 1;
++ }
++ 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);
++
++ /* If network is up, syncronization occurs in ~10 seconds.
++ * We give "ntpd -q" a full minute to finish, then we exit.
++ *
++ * I tested ntpd 4.2.6p1 and apparently it never exits
++ * (will try forever), but it does not feel right.
++ * The goal of -q is to act like ntpdate: set time
++ * after a reasonably small period of polling, or fail.
++ */
++ if (opts & OPT_q)
++ alarm(60);
++
++ bb_signals(0
++ | (1 << SIGTERM)
++ | (1 << SIGINT)
++ | (1 << SIGALRM)
++ , record_signo
++ );
++ bb_signals(0
++ | (1 << SIGPIPE)
++ | (1 << SIGCHLD)
++ , SIG_IGN
++ );
++}
++
++int ntpd_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
++int ntpd_main(int argc UNUSED_PARAM, char **argv)
++{
++#undef G
++ struct globals G;
++ struct pollfd *pfd;
++ peer_t **idx2peer;
++ unsigned cnt;
++
++ memset(&G, 0, sizeof(G));
++ SET_PTR_TO_GLOBALS(&G);
++
++ ntp_init(argv);
++
++ /* If ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
++ cnt = G.peer_cnt + ENABLE_FEATURE_NTPD_SERVER;
++ idx2peer = xzalloc(sizeof(idx2peer[0]) * cnt);
++ pfd = xzalloc(sizeof(pfd[0]) * cnt);
++
++ /* Countdown: we never sync before we sent INITIAL_SAMPLES+1
++ * packets to each peer.
++ * NB: if some peer is not responding, we may end up sending
++ * fewer packets to it and more to other peers.
++ * NB2: sync usually happens using INITIAL_SAMPLES packets,
++ * since last reply does not come back instantaneously.
++ */
++ cnt = G.peer_cnt * (INITIAL_SAMPLES + 1);
++
++ while (!bb_got_signal) {
++ llist_t *item;
++ unsigned i, j;
++ int nfds, timeout;
++ double nextaction;
++
++ /* Nothing between here and poll() blocks for any significant time */
++
++ nextaction = G.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 */
++ for (item = G.ntp_peers; item != NULL; item = item->link) {
++ peer_t *p = (peer_t *) item->data;
++
++ if (p->next_action_time <= G.cur_time) {
++ if (p->p_fd == -1) {
++ /* Time to send new req */
++ if (--cnt == 0) {
++ G.initial_poll_complete = 1;
++ }
++ send_query_to_peer(p);
++ } else {
++ /* Timed out waiting for reply */
++ close(p->p_fd);
++ p->p_fd = -1;
++ timeout = poll_interval(-2); /* -2: try a bit sooner */
++ bb_error_msg("timed out waiting for %s, reach 0x%02x, next query in %us",
++ p->p_dotted, 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++;
++ }
++ }
++
++ timeout = nextaction - G.cur_time;
++ if (timeout < 0)
++ timeout = 0;
++ timeout++; /* (nextaction - G.cur_time) rounds down, compensating */
++
++ /* Here we may block */
++ VERB2 bb_error_msg("poll %us, sockets:%u, poll interval:%us", timeout, i, 1 << G.poll_exp);
++ nfds = poll(pfd, i, timeout * 1000);
++ gettime1900d(); /* sets G.cur_time */
++ if (nfds <= 0) {
++ if (G.script_name && G.cur_time - G.last_script_run > 11*60) {
++ /* Useful for updating battery-backed RTC and such */
++ run_script("periodic", G.last_update_offset);
++ gettime1900d(); /* sets G.cur_time */
++ }
++ 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*/);
++ gettime1900d(); /* sets G.cur_time */
++ }
++ j = 1;
++ }
++#endif
++ for (; nfds != 0 && j < i; j++) {
++ if (pfd[j].revents /* & (POLLIN|POLLERR)*/) {
++ nfds--;
++ recv_and_process_peer_pkt(idx2peer[j]);
++ gettime1900d(); /* sets G.cur_time */
++ }
++ }
++ } /* 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
+--- a/networking/Kbuild
++++ b/networking/Kbuild
+@@ -28,6 +28,7 @@ lib-$(CONFIG_NC) += nc.o
+ lib-$(CONFIG_NETMSG) += netmsg.o
+ lib-$(CONFIG_NETSTAT) += netstat.o
+ lib-$(CONFIG_NSLOOKUP) += nslookup.o
++lib-$(CONFIG_NTPD) += ntpd.o
+ lib-$(CONFIG_PING) += ping.o
+ lib-$(CONFIG_PING6) += ping.o
+ lib-$(CONFIG_PSCAN) += pscan.o
projects / openwrt / svn-archive / openwrt.git / commitdiff