2 * NTP client/server, based on OpenNTPD 3.9p1
4 * Author: Adam Tkac <vonsch@gmail.com>
6 * Licensed under GPLv2, see file LICENSE in this source tree.
8 * Parts of OpenNTPD clock syncronization code is replaced by
9 * code which is based on ntp-4.2.6, whuch carries the following
12 ***********************************************************************
14 * Copyright (c) University of Delaware 1992-2009 *
16 * Permission to use, copy, modify, and distribute this software and *
17 * its documentation for any purpose with or without fee is hereby *
18 * granted, provided that the above copyright notice appears in all *
19 * copies and that both the copyright notice and this permission *
20 * notice appear in supporting documentation, and that the name *
21 * University of Delaware not be used in advertising or publicity *
22 * pertaining to distribution of the software without specific, *
23 * written prior permission. The University of Delaware makes no *
24 * representations about the suitability this software for any *
25 * purpose. It is provided "as is" without express or implied *
28 ***********************************************************************
31 //usage:#define ntpd_trivial_usage
32 //usage: "[-dnqNw"IF_FEATURE_NTPD_SERVER("l")"] [-S PROG] [-p PEER]..."
33 //usage:#define ntpd_full_usage "\n\n"
34 //usage: "NTP client/server\n"
36 //usage: "\n -d Verbose"
37 //usage: "\n -n Do not daemonize"
38 //usage: "\n -q Quit after clock is set"
39 //usage: "\n -N Run at high priority"
40 //usage: "\n -w Do not set time (only query peers), implies -n"
41 //usage: IF_FEATURE_NTPD_SERVER(
42 //usage: "\n -l Run as server on port 123"
44 //usage: "\n -S PROG Run PROG after stepping time, stratum change, and every 11 mins"
45 //usage: "\n -p PEER Obtain time from PEER (may be repeated)"
49 #include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
50 #include <sys/timex.h>
51 #ifndef IPTOS_LOWDELAY
52 # define IPTOS_LOWDELAY 0x10
55 # error "Sorry, your kernel has to support IP_PKTINFO"
59 /* Verbosity control (max level of -dddd options accepted).
60 * max 5 is very talkative (and bloated). 2 is non-bloated,
61 * production level setting.
66 /* High-level description of the algorithm:
68 * We start running with very small poll_exp, BURSTPOLL,
69 * in order to quickly accumulate INITIAL_SAMPLES datapoints
70 * for each peer. Then, time is stepped if the offset is larger
71 * than STEP_THRESHOLD, otherwise it isn't; anyway, we enlarge
72 * poll_exp to MINPOLL and enter frequency measurement step:
73 * we collect new datapoints but ignore them for WATCH_THRESHOLD
74 * seconds. After WATCH_THRESHOLD seconds we look at accumulated
75 * offset and estimate frequency drift.
77 * (frequency measurement step seems to not be strictly needed,
78 * it is conditionally disabled with USING_INITIAL_FREQ_ESTIMATION
81 * After this, we enter "steady state": we collect a datapoint,
82 * we select the best peer, if this datapoint is not a new one
83 * (IOW: if this datapoint isn't for selected peer), sleep
84 * and collect another one; otherwise, use its offset to update
85 * frequency drift, if offset is somewhat large, reduce poll_exp,
86 * otherwise increase poll_exp.
88 * If offset is larger than STEP_THRESHOLD, which shouldn't normally
89 * happen, we assume that something "bad" happened (computer
90 * was hibernated, someone set totally wrong date, etc),
91 * then the time is stepped, all datapoints are discarded,
92 * and we go back to steady state.
95 #define RETRY_INTERVAL 5 /* on error, retry in N secs */
96 #define RESPONSE_INTERVAL 15 /* wait for reply up to N secs */
97 #define INITIAL_SAMPLES 4 /* how many samples do we want for init */
99 /* Clock discipline parameters and constants */
101 /* Step threshold (sec). std ntpd uses 0.128.
102 * Using exact power of 2 (1/8) results in smaller code */
103 #define STEP_THRESHOLD 0.125
104 #define WATCH_THRESHOLD 128 /* stepout threshold (sec). std ntpd uses 900 (11 mins (!)) */
105 /* NB: set WATCH_THRESHOLD to ~60 when debugging to save time) */
106 //UNUSED: #define PANIC_THRESHOLD 1000 /* panic threshold (sec) */
108 #define FREQ_TOLERANCE 0.000015 /* frequency tolerance (15 PPM) */
109 #define BURSTPOLL 0 /* initial poll */
110 #define MINPOLL 5 /* minimum poll interval. std ntpd uses 6 (6: 64 sec) */
111 #define BIGPOLL 10 /* drop to lower poll at any trouble (10: 17 min) */
112 #define MAXPOLL 12 /* maximum poll interval (12: 1.1h, 17: 36.4h). std ntpd uses 17 */
113 /* Actively lower poll when we see such big offsets.
114 * With STEP_THRESHOLD = 0.125, it means we try to sync more aggressively
115 * if offset increases over 0.03 sec */
116 #define POLLDOWN_OFFSET (STEP_THRESHOLD / 4)
117 #define MINDISP 0.01 /* minimum dispersion (sec) */
118 #define MAXDISP 16 /* maximum dispersion (sec) */
119 #define MAXSTRAT 16 /* maximum stratum (infinity metric) */
120 #define MAXDIST 1 /* distance threshold (sec) */
121 #define MIN_SELECTED 1 /* minimum intersection survivors */
122 #define MIN_CLUSTERED 3 /* minimum cluster survivors */
124 #define MAXDRIFT 0.000500 /* frequency drift we can correct (500 PPM) */
126 /* Poll-adjust threshold.
127 * When we see that offset is small enough compared to discipline jitter,
128 * we grow a counter: += MINPOLL. When it goes over POLLADJ_LIMIT,
129 * we poll_exp++. If offset isn't small, counter -= poll_exp*2,
130 * and when it goes below -POLLADJ_LIMIT, we poll_exp--
131 * (bumped from 30 to 36 since otherwise I often see poll_exp going *2* steps down)
133 #define POLLADJ_LIMIT 36
134 /* If offset < POLLADJ_GATE * discipline_jitter, then we can increase
135 * poll interval (we think we can't improve timekeeping
136 * by staying at smaller poll).
138 #define POLLADJ_GATE 4
139 /* Compromise Allan intercept (sec). doc uses 1500, std ntpd uses 512 */
143 /* FLL loop gain [why it depends on MAXPOLL??] */
144 #define FLL (MAXPOLL + 1)
145 /* Parameter averaging constant */
154 NTP_MSGSIZE_NOAUTH = 48,
155 NTP_MSGSIZE = (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE),
158 MODE_MASK = (7 << 0),
159 VERSION_MASK = (7 << 3),
163 /* Leap Second Codes (high order two bits of m_status) */
164 LI_NOWARNING = (0 << 6), /* no warning */
165 LI_PLUSSEC = (1 << 6), /* add a second (61 seconds) */
166 LI_MINUSSEC = (2 << 6), /* minus a second (59 seconds) */
167 LI_ALARM = (3 << 6), /* alarm condition */
170 MODE_RES0 = 0, /* reserved */
171 MODE_SYM_ACT = 1, /* symmetric active */
172 MODE_SYM_PAS = 2, /* symmetric passive */
173 MODE_CLIENT = 3, /* client */
174 MODE_SERVER = 4, /* server */
175 MODE_BROADCAST = 5, /* broadcast */
176 MODE_RES1 = 6, /* reserved for NTP control message */
177 MODE_RES2 = 7, /* reserved for private use */
180 //TODO: better base selection
181 #define OFFSET_1900_1970 2208988800UL /* 1970 - 1900 in seconds */
183 #define NUM_DATAPOINTS 8
196 uint8_t m_status; /* status of local clock and leap info */
198 uint8_t m_ppoll; /* poll value */
199 int8_t m_precision_exp;
200 s_fixedpt_t m_rootdelay;
201 s_fixedpt_t m_rootdisp;
203 l_fixedpt_t m_reftime;
204 l_fixedpt_t m_orgtime;
205 l_fixedpt_t m_rectime;
206 l_fixedpt_t m_xmttime;
208 uint8_t m_digest[NTP_DIGESTSIZE];
218 len_and_sockaddr *p_lsa;
220 /* when to send new query (if p_fd == -1)
221 * or when receive times out (if p_fd >= 0): */
224 uint32_t lastpkt_refid;
225 uint8_t lastpkt_status;
226 uint8_t lastpkt_stratum;
227 uint8_t reachable_bits;
228 double next_action_time;
230 double lastpkt_recv_time;
231 double lastpkt_delay;
232 double lastpkt_rootdelay;
233 double lastpkt_rootdisp;
234 /* produced by filter algorithm: */
235 double filter_offset;
236 double filter_dispersion;
237 double filter_jitter;
238 datapoint_t filter_datapoint[NUM_DATAPOINTS];
239 /* last sent packet: */
244 #define USING_KERNEL_PLL_LOOP 1
245 #define USING_INITIAL_FREQ_ESTIMATION 0
252 /* Insert new options above this line. */
253 /* Non-compat options: */
257 OPT_l = (1 << 7) * ENABLE_FEATURE_NTPD_SERVER,
258 /* We hijack some bits for other purposes */
264 /* total round trip delay to currently selected reference clock */
266 /* reference timestamp: time when the system clock was last set or corrected */
268 /* total dispersion to currently selected reference clock */
271 double last_script_run;
274 #if ENABLE_FEATURE_NTPD_SERVER
279 /* refid: 32-bit code identifying the particular server or reference clock
280 * in stratum 0 packets this is a four-character ASCII string,
281 * called the kiss code, used for debugging and monitoring
282 * in stratum 1 packets this is a four-character ASCII string
283 * assigned to the reference clock by IANA. Example: "GPS "
284 * in stratum 2+ packets, it's IPv4 address or 4 first bytes of MD5 hash of IPv6
288 /* precision is defined as the larger of the resolution and time to
289 * read the clock, in log2 units. For instance, the precision of a
290 * mains-frequency clock incrementing at 60 Hz is 16 ms, even when the
291 * system clock hardware representation is to the nanosecond.
293 * Delays, jitters of various kinds are clamper down to precision.
295 * If precision_sec is too large, discipline_jitter gets clamped to it
296 * and if offset is much smaller than discipline_jitter, poll interval
297 * grows even though we really can benefit from staying at smaller one,
298 * collecting non-lagged datapoits and correcting the offset.
299 * (Lagged datapoits exist when poll_exp is large but we still have
300 * systematic offset error - the time distance between datapoints
301 * is significat and older datapoints have smaller offsets.
302 * This makes our offset estimation a bit smaller than reality)
303 * Due to this effect, setting G_precision_sec close to
304 * STEP_THRESHOLD isn't such a good idea - offsets may grow
305 * too big and we will step. I observed it with -6.
307 * OTOH, setting precision too small would result in futile attempts
308 * to syncronize to the unachievable precision.
310 * -6 is 1/64 sec, -7 is 1/128 sec and so on.
312 #define G_precision_exp -8
313 #define G_precision_sec (1.0 / (1 << (- G_precision_exp)))
315 /* Bool. After set to 1, never goes back to 0: */
316 smallint initial_poll_complete;
318 #define STATE_NSET 0 /* initial state, "nothing is set" */
319 //#define STATE_FSET 1 /* frequency set from file */
320 #define STATE_SPIK 2 /* spike detected */
321 //#define STATE_FREQ 3 /* initial frequency */
322 #define STATE_SYNC 4 /* clock synchronized (normal operation) */
323 uint8_t discipline_state; // doc calls it c.state
324 uint8_t poll_exp; // s.poll
325 int polladj_count; // c.count
326 long kernel_freq_drift;
327 peer_t *last_update_peer;
328 double last_update_offset; // c.last
329 double last_update_recv_time; // s.t
330 double discipline_jitter; // c.jitter
331 //double cluster_offset; // s.offset
332 //double cluster_jitter; // s.jitter
333 #if !USING_KERNEL_PLL_LOOP
334 double discipline_freq_drift; // c.freq
335 /* Maybe conditionally calculate wander? it's used only for logging */
336 double discipline_wander; // c.wander
339 #define G (*ptr_to_globals)
341 static const int const_IPTOS_LOWDELAY = IPTOS_LOWDELAY;
344 #define VERB1 if (MAX_VERBOSE && G.verbose)
345 #define VERB2 if (MAX_VERBOSE >= 2 && G.verbose >= 2)
346 #define VERB3 if (MAX_VERBOSE >= 3 && G.verbose >= 3)
347 #define VERB4 if (MAX_VERBOSE >= 4 && G.verbose >= 4)
348 #define VERB5 if (MAX_VERBOSE >= 5 && G.verbose >= 5)
351 static double LOG2D(int a)
354 return 1.0 / (1UL << -a);
357 static ALWAYS_INLINE double SQUARE(double x)
361 static ALWAYS_INLINE double MAXD(double a, double b)
367 static ALWAYS_INLINE double MIND(double a, double b)
373 static NOINLINE double my_SQRT(double X)
380 double Xhalf = X * 0.5;
382 /* Fast and good approximation to 1/sqrt(X), black magic */
384 /*v.i = 0x5f3759df - (v.i >> 1);*/
385 v.i = 0x5f375a86 - (v.i >> 1); /* - this constant is slightly better */
386 invsqrt = v.f; /* better than 0.2% accuracy */
388 /* Refining it using Newton's method: x1 = x0 - f(x0)/f'(x0)
389 * f(x) = 1/(x*x) - X (f==0 when x = 1/sqrt(X))
391 * f(x)/f'(x) = (X - 1/(x*x)) / (2/(x*x*x)) = X*x*x*x/2 - x/2
392 * x1 = x0 - (X*x0*x0*x0/2 - x0/2) = 1.5*x0 - X*x0*x0*x0/2 = x0*(1.5 - (X/2)*x0*x0)
394 invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); /* ~0.05% accuracy */
395 /* invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); 2nd iter: ~0.0001% accuracy */
396 /* With 4 iterations, more than half results will be exact,
397 * at 6th iterations result stabilizes with about 72% results exact.
398 * We are well satisfied with 0.05% accuracy.
401 return X * invsqrt; /* X * 1/sqrt(X) ~= sqrt(X) */
403 static ALWAYS_INLINE double SQRT(double X)
405 /* If this arch doesn't use IEEE 754 floats, fall back to using libm */
406 if (sizeof(float) != 4)
409 /* This avoids needing libm, saves about 0.5k on x86-32 */
417 gettimeofday(&tv, NULL); /* never fails */
418 G.cur_time = tv.tv_sec + (1.0e-6 * tv.tv_usec) + OFFSET_1900_1970;
423 d_to_tv(double d, struct timeval *tv)
425 tv->tv_sec = (long)d;
426 tv->tv_usec = (d - tv->tv_sec) * 1000000;
430 lfp_to_d(l_fixedpt_t lfp)
433 lfp.int_partl = ntohl(lfp.int_partl);
434 lfp.fractionl = ntohl(lfp.fractionl);
435 ret = (double)lfp.int_partl + ((double)lfp.fractionl / UINT_MAX);
439 sfp_to_d(s_fixedpt_t sfp)
442 sfp.int_parts = ntohs(sfp.int_parts);
443 sfp.fractions = ntohs(sfp.fractions);
444 ret = (double)sfp.int_parts + ((double)sfp.fractions / USHRT_MAX);
447 #if ENABLE_FEATURE_NTPD_SERVER
452 lfp.int_partl = (uint32_t)d;
453 lfp.fractionl = (uint32_t)((d - lfp.int_partl) * UINT_MAX);
454 lfp.int_partl = htonl(lfp.int_partl);
455 lfp.fractionl = htonl(lfp.fractionl);
462 sfp.int_parts = (uint16_t)d;
463 sfp.fractions = (uint16_t)((d - sfp.int_parts) * USHRT_MAX);
464 sfp.int_parts = htons(sfp.int_parts);
465 sfp.fractions = htons(sfp.fractions);
471 dispersion(const datapoint_t *dp)
473 return dp->d_dispersion + FREQ_TOLERANCE * (G.cur_time - dp->d_recv_time);
477 root_distance(peer_t *p)
479 /* The root synchronization distance is the maximum error due to
480 * all causes of the local clock relative to the primary server.
481 * It is defined as half the total delay plus total dispersion
484 return MAXD(MINDISP, p->lastpkt_rootdelay + p->lastpkt_delay) / 2
485 + p->lastpkt_rootdisp
486 + p->filter_dispersion
487 + FREQ_TOLERANCE * (G.cur_time - p->lastpkt_recv_time)
492 set_next(peer_t *p, unsigned t)
494 p->next_action_time = G.cur_time + t;
498 * Peer clock filter and its helpers
501 filter_datapoints(peer_t *p)
505 double minoff, maxoff, wavg, sum, w;
506 double x = x; /* for compiler */
507 double oldest_off = oldest_off;
508 double oldest_age = oldest_age;
509 double newest_off = newest_off;
510 double newest_age = newest_age;
512 minoff = maxoff = p->filter_datapoint[0].d_offset;
513 for (i = 1; i < NUM_DATAPOINTS; i++) {
514 if (minoff > p->filter_datapoint[i].d_offset)
515 minoff = p->filter_datapoint[i].d_offset;
516 if (maxoff < p->filter_datapoint[i].d_offset)
517 maxoff = p->filter_datapoint[i].d_offset;
520 idx = p->datapoint_idx; /* most recent datapoint */
522 * Drop two outliers and take weighted average of the rest:
523 * most_recent/2 + older1/4 + older2/8 ... + older5/32 + older6/32
524 * we use older6/32, not older6/64 since sum of weights should be 1:
525 * 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/32 = 1
531 * filter_dispersion = \ -------------
538 for (i = 0; i < NUM_DATAPOINTS; i++) {
540 bb_error_msg("datapoint[%d]: off:%f disp:%f(%f) age:%f%s",
542 p->filter_datapoint[idx].d_offset,
543 p->filter_datapoint[idx].d_dispersion, dispersion(&p->filter_datapoint[idx]),
544 G.cur_time - p->filter_datapoint[idx].d_recv_time,
545 (minoff == p->filter_datapoint[idx].d_offset || maxoff == p->filter_datapoint[idx].d_offset)
546 ? " (outlier by offset)" : ""
550 sum += dispersion(&p->filter_datapoint[idx]) / (2 << i);
552 if (minoff == p->filter_datapoint[idx].d_offset) {
553 minoff -= 1; /* so that we don't match it ever again */
555 if (maxoff == p->filter_datapoint[idx].d_offset) {
558 oldest_off = p->filter_datapoint[idx].d_offset;
559 oldest_age = G.cur_time - p->filter_datapoint[idx].d_recv_time;
562 newest_off = oldest_off;
563 newest_age = oldest_age;
570 idx = (idx - 1) & (NUM_DATAPOINTS - 1);
572 p->filter_dispersion = sum;
573 wavg += x; /* add another older6/64 to form older6/32 */
574 /* Fix systematic underestimation with large poll intervals.
575 * Imagine that we still have a bit of uncorrected drift,
576 * and poll interval is big (say, 100 sec). Offsets form a progression:
577 * 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 - 0.7 is most recent.
578 * The algorithm above drops 0.0 and 0.7 as outliers,
579 * and then we have this estimation, ~25% off from 0.7:
580 * 0.1/32 + 0.2/32 + 0.3/16 + 0.4/8 + 0.5/4 + 0.6/2 = 0.503125
582 x = oldest_age - newest_age;
584 x = newest_age / x; /* in above example, 100 / (600 - 100) */
585 if (x < 1) { /* paranoia check */
586 x = (newest_off - oldest_off) * x; /* 0.5 * 100/500 = 0.1 */
590 p->filter_offset = wavg;
592 /* +----- -----+ ^ 1/2
596 * filter_jitter = | --- * / (avg-offset_j) |
600 * where n is the number of valid datapoints in the filter (n > 1);
601 * if filter_jitter < precision then filter_jitter = precision
604 for (i = 0; i < NUM_DATAPOINTS; i++) {
605 sum += SQUARE(wavg - p->filter_datapoint[i].d_offset);
607 sum = SQRT(sum / NUM_DATAPOINTS);
608 p->filter_jitter = sum > G_precision_sec ? sum : G_precision_sec;
610 VERB3 bb_error_msg("filter offset:%f(corr:%e) disp:%f jitter:%f",
612 p->filter_dispersion,
617 reset_peer_stats(peer_t *p, double offset)
620 bool small_ofs = fabs(offset) < 16 * STEP_THRESHOLD;
622 for (i = 0; i < NUM_DATAPOINTS; i++) {
624 p->filter_datapoint[i].d_recv_time += offset;
625 if (p->filter_datapoint[i].d_offset != 0) {
626 p->filter_datapoint[i].d_offset += offset;
629 p->filter_datapoint[i].d_recv_time = G.cur_time;
630 p->filter_datapoint[i].d_offset = 0;
631 p->filter_datapoint[i].d_dispersion = MAXDISP;
635 p->lastpkt_recv_time += offset;
637 p->reachable_bits = 0;
638 p->lastpkt_recv_time = G.cur_time;
640 filter_datapoints(p); /* recalc p->filter_xxx */
641 VERB5 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
649 p = xzalloc(sizeof(*p));
650 p->p_lsa = xhost2sockaddr(s, 123);
651 p->p_dotted = xmalloc_sockaddr2dotted_noport(&p->p_lsa->u.sa);
653 p->p_xmt_msg.m_status = MODE_CLIENT | (NTP_VERSION << 3);
654 p->next_action_time = G.cur_time; /* = set_next(p, 0); */
655 reset_peer_stats(p, 16 * STEP_THRESHOLD);
657 llist_add_to(&G.ntp_peers, p);
663 const struct sockaddr *from, const struct sockaddr *to, socklen_t addrlen,
664 msg_t *msg, ssize_t len)
670 ret = sendto(fd, msg, len, MSG_DONTWAIT, to, addrlen);
672 ret = send_to_from(fd, msg, len, MSG_DONTWAIT, to, from, addrlen);
675 bb_perror_msg("send failed");
682 send_query_to_peer(peer_t *p)
684 /* Why do we need to bind()?
685 * See what happens when we don't bind:
687 * socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
688 * setsockopt(3, SOL_IP, IP_TOS, [16], 4) = 0
689 * gettimeofday({1259071266, 327885}, NULL) = 0
690 * sendto(3, "xxx", 48, MSG_DONTWAIT, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr("10.34.32.125")}, 16) = 48
691 * ^^^ we sent it from some source port picked by kernel.
692 * time(NULL) = 1259071266
693 * write(2, "ntpd: entering poll 15 secs\n", 28) = 28
694 * poll([{fd=3, events=POLLIN}], 1, 15000) = 1 ([{fd=3, revents=POLLIN}])
695 * recv(3, "yyy", 68, MSG_DONTWAIT) = 48
696 * ^^^ this recv will receive packets to any local port!
698 * Uncomment this and use strace to see it in action:
700 #define PROBE_LOCAL_ADDR /* { len_and_sockaddr lsa; lsa.len = LSA_SIZEOF_SA; getsockname(p->query.fd, &lsa.u.sa, &lsa.len); } */
704 len_and_sockaddr *local_lsa;
706 family = p->p_lsa->u.sa.sa_family;
707 p->p_fd = fd = xsocket_type(&local_lsa, family, SOCK_DGRAM);
708 /* local_lsa has "null" address and port 0 now.
709 * bind() ensures we have a *particular port* selected by kernel
710 * and remembered in p->p_fd, thus later recv(p->p_fd)
711 * receives only packets sent to this port.
714 xbind(fd, &local_lsa->u.sa, local_lsa->len);
716 #if ENABLE_FEATURE_IPV6
717 if (family == AF_INET)
719 setsockopt(fd, IPPROTO_IP, IP_TOS, &const_IPTOS_LOWDELAY, sizeof(const_IPTOS_LOWDELAY));
724 * Send out a random 64-bit number as our transmit time. The NTP
725 * server will copy said number into the originate field on the
726 * response that it sends us. This is totally legal per the SNTP spec.
728 * The impact of this is two fold: we no longer send out the current
729 * system time for the world to see (which may aid an attacker), and
730 * it gives us a (not very secure) way of knowing that we're not
731 * getting spoofed by an attacker that can't capture our traffic
732 * but can spoof packets from the NTP server we're communicating with.
734 * Save the real transmit timestamp locally.
736 p->p_xmt_msg.m_xmttime.int_partl = random();
737 p->p_xmt_msg.m_xmttime.fractionl = random();
738 p->p_xmttime = gettime1900d();
740 if (do_sendto(p->p_fd, /*from:*/ NULL, /*to:*/ &p->p_lsa->u.sa, /*addrlen:*/ p->p_lsa->len,
741 &p->p_xmt_msg, NTP_MSGSIZE_NOAUTH) == -1
745 set_next(p, RETRY_INTERVAL);
749 p->reachable_bits <<= 1;
750 VERB1 bb_error_msg("sent query to %s", p->p_dotted);
751 set_next(p, RESPONSE_INTERVAL);
755 /* Note that there is no provision to prevent several run_scripts
756 * to be done in quick succession. In fact, it happens rather often
757 * if initial syncronization results in a step.
758 * You will see "step" and then "stratum" script runs, sometimes
759 * as close as only 0.002 seconds apart.
760 * Script should be ready to deal with this.
762 static void run_script(const char *action, double offset)
765 char *env1, *env2, *env3, *env4;
770 argv[0] = (char*) G.script_name;
771 argv[1] = (char*) action;
774 VERB1 bb_error_msg("executing '%s %s'", G.script_name, action);
776 env1 = xasprintf("%s=%u", "stratum", G.stratum);
778 env2 = xasprintf("%s=%ld", "freq_drift_ppm", G.kernel_freq_drift);
780 env3 = xasprintf("%s=%u", "poll_interval", 1 << G.poll_exp);
782 env4 = xasprintf("%s=%f", "offset", offset);
784 /* Other items of potential interest: selected peer,
785 * rootdelay, reftime, rootdisp, refid, ntp_status,
786 * last_update_offset, last_update_recv_time, discipline_jitter,
787 * how many peers have reachable_bits = 0?
790 /* Don't want to wait: it may run hwclock --systohc, and that
791 * may take some time (seconds): */
792 /*spawn_and_wait(argv);*/
796 unsetenv("freq_drift_ppm");
797 unsetenv("poll_interval");
804 G.last_script_run = G.cur_time;
808 step_time(double offset)
816 gettimeofday(&tv, NULL); /* never fails */
817 dtime = offset + tv.tv_sec;
818 dtime += 1.0e-6 * tv.tv_usec;
821 if (settimeofday(&tv, NULL) == -1)
822 bb_perror_msg_and_die("settimeofday");
825 strftime(buf, sizeof(buf), "%a %b %e %H:%M:%S %Z %Y", localtime(&tval));
827 bb_error_msg("setting clock to %s (offset %fs)", buf, offset);
829 /* Correct various fields which contain time-relative values: */
831 /* p->lastpkt_recv_time, p->next_action_time and such: */
832 for (item = G.ntp_peers; item != NULL; item = item->link) {
833 peer_t *pp = (peer_t *) item->data;
834 reset_peer_stats(pp, offset);
835 //bb_error_msg("offset:%f pp->next_action_time:%f -> %f",
836 // offset, pp->next_action_time, pp->next_action_time + offset);
837 pp->next_action_time += offset;
840 G.cur_time += offset;
841 G.last_update_recv_time += offset;
842 G.last_script_run += offset;
847 * Selection and clustering, and their helpers
853 double opt_rd; /* optimization */
856 compare_point_edge(const void *aa, const void *bb)
858 const point_t *a = aa;
859 const point_t *b = bb;
860 if (a->edge < b->edge) {
863 return (a->edge > b->edge);
870 compare_survivor_metric(const void *aa, const void *bb)
872 const survivor_t *a = aa;
873 const survivor_t *b = bb;
874 if (a->metric < b->metric) {
877 return (a->metric > b->metric);
880 fit(peer_t *p, double rd)
882 if ((p->reachable_bits & (p->reachable_bits-1)) == 0) {
883 /* One or zero bits in reachable_bits */
884 VERB3 bb_error_msg("peer %s unfit for selection: unreachable", p->p_dotted);
887 #if 0 /* we filter out such packets earlier */
888 if ((p->lastpkt_status & LI_ALARM) == LI_ALARM
889 || p->lastpkt_stratum >= MAXSTRAT
891 VERB3 bb_error_msg("peer %s unfit for selection: bad status/stratum", p->p_dotted);
895 /* rd is root_distance(p) */
896 if (rd > MAXDIST + FREQ_TOLERANCE * (1 << G.poll_exp)) {
897 VERB3 bb_error_msg("peer %s unfit for selection: root distance too high", p->p_dotted);
901 // /* Do we have a loop? */
902 // if (p->refid == p->dstaddr || p->refid == s.refid)
907 select_and_cluster(void)
912 int size = 3 * G.peer_cnt;
913 /* for selection algorithm */
915 unsigned num_points, num_candidates;
917 unsigned num_falsetickers;
918 /* for cluster algorithm */
919 survivor_t survivor[size];
920 unsigned num_survivors;
926 if (G.initial_poll_complete) while (item != NULL) {
929 p = (peer_t *) item->data;
930 rd = root_distance(p);
931 offset = p->filter_offset;
937 VERB4 bb_error_msg("interval: [%f %f %f] %s",
943 point[num_points].p = p;
944 point[num_points].type = -1;
945 point[num_points].edge = offset - rd;
946 point[num_points].opt_rd = rd;
948 point[num_points].p = p;
949 point[num_points].type = 0;
950 point[num_points].edge = offset;
951 point[num_points].opt_rd = rd;
953 point[num_points].p = p;
954 point[num_points].type = 1;
955 point[num_points].edge = offset + rd;
956 point[num_points].opt_rd = rd;
960 num_candidates = num_points / 3;
961 if (num_candidates == 0) {
962 VERB3 bb_error_msg("no valid datapoints, no peer selected");
965 //TODO: sorting does not seem to be done in reference code
966 qsort(point, num_points, sizeof(point[0]), compare_point_edge);
968 /* Start with the assumption that there are no falsetickers.
969 * Attempt to find a nonempty intersection interval containing
970 * the midpoints of all truechimers.
971 * If a nonempty interval cannot be found, increase the number
972 * of assumed falsetickers by one and try again.
973 * If a nonempty interval is found and the number of falsetickers
974 * is less than the number of truechimers, a majority has been found
975 * and the midpoint of each truechimer represents
976 * the candidates available to the cluster algorithm.
978 num_falsetickers = 0;
981 unsigned num_midpoints = 0;
986 for (i = 0; i < num_points; i++) {
988 * if (point[i].type == -1) c++;
989 * if (point[i].type == 1) c--;
990 * and it's simpler to do it this way:
993 if (c >= num_candidates - num_falsetickers) {
994 /* If it was c++ and it got big enough... */
998 if (point[i].type == 0)
1002 for (i = num_points-1; i >= 0; i--) {
1004 if (c >= num_candidates - num_falsetickers) {
1005 high = point[i].edge;
1008 if (point[i].type == 0)
1011 /* If the number of midpoints is greater than the number
1012 * of allowed falsetickers, the intersection contains at
1013 * least one truechimer with no midpoint - bad.
1014 * Also, interval should be nonempty.
1016 if (num_midpoints <= num_falsetickers && low < high)
1019 if (num_falsetickers * 2 >= num_candidates) {
1020 VERB3 bb_error_msg("too many falsetickers:%d (candidates:%d), no peer selected",
1021 num_falsetickers, num_candidates);
1025 VERB3 bb_error_msg("selected interval: [%f, %f]; candidates:%d falsetickers:%d",
1026 low, high, num_candidates, num_falsetickers);
1030 /* Construct a list of survivors (p, metric)
1031 * from the chime list, where metric is dominated
1032 * first by stratum and then by root distance.
1033 * All other things being equal, this is the order of preference.
1036 for (i = 0; i < num_points; i++) {
1037 if (point[i].edge < low || point[i].edge > high)
1040 survivor[num_survivors].p = p;
1041 /* x.opt_rd == root_distance(p); */
1042 survivor[num_survivors].metric = MAXDIST * p->lastpkt_stratum + point[i].opt_rd;
1043 VERB4 bb_error_msg("survivor[%d] metric:%f peer:%s",
1044 num_survivors, survivor[num_survivors].metric, p->p_dotted);
1047 /* There must be at least MIN_SELECTED survivors to satisfy the
1048 * correctness assertions. Ordinarily, the Byzantine criteria
1049 * require four survivors, but for the demonstration here, one
1052 if (num_survivors < MIN_SELECTED) {
1053 VERB3 bb_error_msg("num_survivors %d < %d, no peer selected",
1054 num_survivors, MIN_SELECTED);
1058 //looks like this is ONLY used by the fact that later we pick survivor[0].
1059 //we can avoid sorting then, just find the minimum once!
1060 qsort(survivor, num_survivors, sizeof(survivor[0]), compare_survivor_metric);
1062 /* For each association p in turn, calculate the selection
1063 * jitter p->sjitter as the square root of the sum of squares
1064 * (p->offset - q->offset) over all q associations. The idea is
1065 * to repeatedly discard the survivor with maximum selection
1066 * jitter until a termination condition is met.
1069 unsigned max_idx = max_idx;
1070 double max_selection_jitter = max_selection_jitter;
1071 double min_jitter = min_jitter;
1073 if (num_survivors <= MIN_CLUSTERED) {
1074 VERB3 bb_error_msg("num_survivors %d <= %d, not discarding more",
1075 num_survivors, MIN_CLUSTERED);
1079 /* To make sure a few survivors are left
1080 * for the clustering algorithm to chew on,
1081 * we stop if the number of survivors
1082 * is less than or equal to MIN_CLUSTERED (3).
1084 for (i = 0; i < num_survivors; i++) {
1085 double selection_jitter_sq;
1088 if (i == 0 || p->filter_jitter < min_jitter)
1089 min_jitter = p->filter_jitter;
1091 selection_jitter_sq = 0;
1092 for (j = 0; j < num_survivors; j++) {
1093 peer_t *q = survivor[j].p;
1094 selection_jitter_sq += SQUARE(p->filter_offset - q->filter_offset);
1096 if (i == 0 || selection_jitter_sq > max_selection_jitter) {
1097 max_selection_jitter = selection_jitter_sq;
1100 VERB5 bb_error_msg("survivor %d selection_jitter^2:%f",
1101 i, selection_jitter_sq);
1103 max_selection_jitter = SQRT(max_selection_jitter / num_survivors);
1104 VERB4 bb_error_msg("max_selection_jitter (at %d):%f min_jitter:%f",
1105 max_idx, max_selection_jitter, min_jitter);
1107 /* If the maximum selection jitter is less than the
1108 * minimum peer jitter, then tossing out more survivors
1109 * will not lower the minimum peer jitter, so we might
1112 if (max_selection_jitter < min_jitter) {
1113 VERB3 bb_error_msg("max_selection_jitter:%f < min_jitter:%f, num_survivors:%d, not discarding more",
1114 max_selection_jitter, min_jitter, num_survivors);
1118 /* Delete survivor[max_idx] from the list
1119 * and go around again.
1121 VERB5 bb_error_msg("dropping survivor %d", max_idx);
1123 while (max_idx < num_survivors) {
1124 survivor[max_idx] = survivor[max_idx + 1];
1130 /* Combine the offsets of the clustering algorithm survivors
1131 * using a weighted average with weight determined by the root
1132 * distance. Compute the selection jitter as the weighted RMS
1133 * difference between the first survivor and the remaining
1134 * survivors. In some cases the inherent clock jitter can be
1135 * reduced by not using this algorithm, especially when frequent
1136 * clockhopping is involved. bbox: thus we don't do it.
1140 for (i = 0; i < num_survivors; i++) {
1142 x = root_distance(p);
1144 z += p->filter_offset / x;
1145 w += SQUARE(p->filter_offset - survivor[0].p->filter_offset) / x;
1147 //G.cluster_offset = z / y;
1148 //G.cluster_jitter = SQRT(w / y);
1151 /* Pick the best clock. If the old system peer is on the list
1152 * and at the same stratum as the first survivor on the list,
1153 * then don't do a clock hop. Otherwise, select the first
1154 * survivor on the list as the new system peer.
1157 if (G.last_update_peer
1158 && G.last_update_peer->lastpkt_stratum <= p->lastpkt_stratum
1160 /* Starting from 1 is ok here */
1161 for (i = 1; i < num_survivors; i++) {
1162 if (G.last_update_peer == survivor[i].p) {
1163 VERB4 bb_error_msg("keeping old synced peer");
1164 p = G.last_update_peer;
1169 G.last_update_peer = p;
1171 VERB3 bb_error_msg("selected peer %s filter_offset:%f age:%f",
1174 G.cur_time - p->lastpkt_recv_time
1181 * Local clock discipline and its helpers
1184 set_new_values(int disc_state, double offset, double recv_time)
1186 /* Enter new state and set state variables. Note we use the time
1187 * of the last clock filter sample, which must be earlier than
1190 VERB3 bb_error_msg("disc_state=%d last update offset=%f recv_time=%f",
1191 disc_state, offset, recv_time);
1192 G.discipline_state = disc_state;
1193 G.last_update_offset = offset;
1194 G.last_update_recv_time = recv_time;
1196 /* Return: -1: decrease poll interval, 0: leave as is, 1: increase */
1198 update_local_clock(peer_t *p)
1202 /* Note: can use G.cluster_offset instead: */
1203 double offset = p->filter_offset;
1204 double recv_time = p->lastpkt_recv_time;
1206 #if !USING_KERNEL_PLL_LOOP
1209 double since_last_update;
1210 double etemp, dtemp;
1212 abs_offset = fabs(offset);
1215 /* If needed, -S script can do it by looking at $offset
1216 * env var and killing parent */
1217 /* If the offset is too large, give up and go home */
1218 if (abs_offset > PANIC_THRESHOLD) {
1219 bb_error_msg_and_die("offset %f far too big, exiting", offset);
1223 /* If this is an old update, for instance as the result
1224 * of a system peer change, avoid it. We never use
1225 * an old sample or the same sample twice.
1227 if (recv_time <= G.last_update_recv_time) {
1228 VERB3 bb_error_msg("same or older datapoint: %f >= %f, not using it",
1229 G.last_update_recv_time, recv_time);
1230 return 0; /* "leave poll interval as is" */
1233 /* Clock state machine transition function. This is where the
1234 * action is and defines how the system reacts to large time
1235 * and frequency errors.
1237 since_last_update = recv_time - G.reftime;
1238 #if !USING_KERNEL_PLL_LOOP
1241 #if USING_INITIAL_FREQ_ESTIMATION
1242 if (G.discipline_state == STATE_FREQ) {
1243 /* Ignore updates until the stepout threshold */
1244 if (since_last_update < WATCH_THRESHOLD) {
1245 VERB3 bb_error_msg("measuring drift, datapoint ignored, %f sec remains",
1246 WATCH_THRESHOLD - since_last_update);
1247 return 0; /* "leave poll interval as is" */
1249 # if !USING_KERNEL_PLL_LOOP
1250 freq_drift = (offset - G.last_update_offset) / since_last_update;
1255 /* There are two main regimes: when the
1256 * offset exceeds the step threshold and when it does not.
1258 if (abs_offset > STEP_THRESHOLD) {
1259 switch (G.discipline_state) {
1261 /* The first outlyer: ignore it, switch to SPIK state */
1262 VERB3 bb_error_msg("offset:%f - spike detected", offset);
1263 G.discipline_state = STATE_SPIK;
1264 return -1; /* "decrease poll interval" */
1267 /* Ignore succeeding outlyers until either an inlyer
1268 * is found or the stepout threshold is exceeded.
1270 if (since_last_update < WATCH_THRESHOLD) {
1271 VERB3 bb_error_msg("spike detected, datapoint ignored, %f sec remains",
1272 WATCH_THRESHOLD - since_last_update);
1273 return -1; /* "decrease poll interval" */
1275 /* fall through: we need to step */
1278 /* Step the time and clamp down the poll interval.
1280 * In NSET state an initial frequency correction is
1281 * not available, usually because the frequency file has
1282 * not yet been written. Since the time is outside the
1283 * capture range, the clock is stepped. The frequency
1284 * will be set directly following the stepout interval.
1286 * In FSET state the initial frequency has been set
1287 * from the frequency file. Since the time is outside
1288 * the capture range, the clock is stepped immediately,
1289 * rather than after the stepout interval. Guys get
1290 * nervous if it takes 17 minutes to set the clock for
1293 * In SPIK state the stepout threshold has expired and
1294 * the phase is still above the step threshold. Note
1295 * that a single spike greater than the step threshold
1296 * is always suppressed, even at the longer poll
1299 VERB3 bb_error_msg("stepping time by %f; poll_exp=MINPOLL", offset);
1301 if (option_mask32 & OPT_q) {
1302 /* We were only asked to set time once. Done. */
1306 G.polladj_count = 0;
1307 G.poll_exp = MINPOLL;
1308 G.stratum = MAXSTRAT;
1310 run_script("step", offset);
1312 #if USING_INITIAL_FREQ_ESTIMATION
1313 if (G.discipline_state == STATE_NSET) {
1314 set_new_values(STATE_FREQ, /*offset:*/ 0, recv_time);
1315 return 1; /* "ok to increase poll interval" */
1318 set_new_values(STATE_SYNC, /*offset:*/ 0, recv_time);
1320 } else { /* abs_offset <= STEP_THRESHOLD */
1322 if (G.poll_exp < MINPOLL && G.initial_poll_complete) {
1323 VERB3 bb_error_msg("small offset:%f, disabling burst mode", offset);
1324 G.polladj_count = 0;
1325 G.poll_exp = MINPOLL;
1328 /* Compute the clock jitter as the RMS of exponentially
1329 * weighted offset differences. Used by the poll adjust code.
1331 etemp = SQUARE(G.discipline_jitter);
1332 dtemp = SQUARE(MAXD(fabs(offset - G.last_update_offset), G_precision_sec));
1333 G.discipline_jitter = SQRT(etemp + (dtemp - etemp) / AVG);
1334 VERB3 bb_error_msg("discipline jitter=%f", G.discipline_jitter);
1336 switch (G.discipline_state) {
1338 if (option_mask32 & OPT_q) {
1339 /* We were only asked to set time once.
1340 * The clock is precise enough, no need to step.
1344 #if USING_INITIAL_FREQ_ESTIMATION
1345 /* This is the first update received and the frequency
1346 * has not been initialized. The first thing to do
1347 * is directly measure the oscillator frequency.
1349 set_new_values(STATE_FREQ, offset, recv_time);
1351 set_new_values(STATE_SYNC, offset, recv_time);
1353 VERB3 bb_error_msg("transitioning to FREQ, datapoint ignored");
1354 return 0; /* "leave poll interval as is" */
1356 #if 0 /* this is dead code for now */
1358 /* This is the first update and the frequency
1359 * has been initialized. Adjust the phase, but
1360 * don't adjust the frequency until the next update.
1362 set_new_values(STATE_SYNC, offset, recv_time);
1363 /* freq_drift remains 0 */
1367 #if USING_INITIAL_FREQ_ESTIMATION
1369 /* since_last_update >= WATCH_THRESHOLD, we waited enough.
1370 * Correct the phase and frequency and switch to SYNC state.
1371 * freq_drift was already estimated (see code above)
1373 set_new_values(STATE_SYNC, offset, recv_time);
1378 #if !USING_KERNEL_PLL_LOOP
1379 /* Compute freq_drift due to PLL and FLL contributions.
1381 * The FLL and PLL frequency gain constants
1382 * depend on the poll interval and Allan
1383 * intercept. The FLL is not used below one-half
1384 * the Allan intercept. Above that the loop gain
1385 * increases in steps to 1 / AVG.
1387 if ((1 << G.poll_exp) > ALLAN / 2) {
1388 etemp = FLL - G.poll_exp;
1391 freq_drift += (offset - G.last_update_offset) / (MAXD(since_last_update, ALLAN) * etemp);
1393 /* For the PLL the integration interval
1394 * (numerator) is the minimum of the update
1395 * interval and poll interval. This allows
1396 * oversampling, but not undersampling.
1398 etemp = MIND(since_last_update, (1 << G.poll_exp));
1399 dtemp = (4 * PLL) << G.poll_exp;
1400 freq_drift += offset * etemp / SQUARE(dtemp);
1402 set_new_values(STATE_SYNC, offset, recv_time);
1405 if (G.stratum != p->lastpkt_stratum + 1) {
1406 G.stratum = p->lastpkt_stratum + 1;
1407 run_script("stratum", offset);
1411 G.reftime = G.cur_time;
1412 G.ntp_status = p->lastpkt_status;
1413 G.refid = p->lastpkt_refid;
1414 G.rootdelay = p->lastpkt_rootdelay + p->lastpkt_delay;
1415 dtemp = p->filter_jitter; // SQRT(SQUARE(p->filter_jitter) + SQUARE(G.cluster_jitter));
1416 dtemp += MAXD(p->filter_dispersion + FREQ_TOLERANCE * (G.cur_time - p->lastpkt_recv_time) + abs_offset, MINDISP);
1417 G.rootdisp = p->lastpkt_rootdisp + dtemp;
1418 VERB3 bb_error_msg("updating leap/refid/reftime/rootdisp from peer %s", p->p_dotted);
1420 /* We are in STATE_SYNC now, but did not do adjtimex yet.
1421 * (Any other state does not reach this, they all return earlier)
1422 * By this time, freq_drift and G.last_update_offset are set
1423 * to values suitable for adjtimex.
1425 #if !USING_KERNEL_PLL_LOOP
1426 /* Calculate the new frequency drift and frequency stability (wander).
1427 * Compute the clock wander as the RMS of exponentially weighted
1428 * frequency differences. This is not used directly, but can,
1429 * along with the jitter, be a highly useful monitoring and
1432 dtemp = G.discipline_freq_drift + freq_drift;
1433 G.discipline_freq_drift = MAXD(MIND(MAXDRIFT, dtemp), -MAXDRIFT);
1434 etemp = SQUARE(G.discipline_wander);
1435 dtemp = SQUARE(dtemp);
1436 G.discipline_wander = SQRT(etemp + (dtemp - etemp) / AVG);
1438 VERB3 bb_error_msg("discipline freq_drift=%.9f(int:%ld corr:%e) wander=%f",
1439 G.discipline_freq_drift,
1440 (long)(G.discipline_freq_drift * 65536e6),
1442 G.discipline_wander);
1445 memset(&tmx, 0, sizeof(tmx));
1446 if (adjtimex(&tmx) < 0)
1447 bb_perror_msg_and_die("adjtimex");
1448 VERB3 bb_error_msg("p adjtimex freq:%ld offset:%ld constant:%ld status:0x%x",
1449 tmx.freq, tmx.offset, tmx.constant, tmx.status);
1452 memset(&tmx, 0, sizeof(tmx));
1454 //doesn't work, offset remains 0 (!) in kernel:
1455 //ntpd: set adjtimex freq:1786097 tmx.offset:77487
1456 //ntpd: prev adjtimex freq:1786097 tmx.offset:0
1457 //ntpd: cur adjtimex freq:1786097 tmx.offset:0
1458 tmx.modes = ADJ_FREQUENCY | ADJ_OFFSET;
1459 /* 65536 is one ppm */
1460 tmx.freq = G.discipline_freq_drift * 65536e6;
1461 tmx.offset = G.last_update_offset * 1000000; /* usec */
1463 tmx.modes = ADJ_OFFSET | ADJ_STATUS | ADJ_TIMECONST;// | ADJ_MAXERROR | ADJ_ESTERROR;
1464 tmx.offset = (G.last_update_offset * 1000000); /* usec */
1465 /* + (G.last_update_offset < 0 ? -0.5 : 0.5) - too small to bother */
1466 tmx.status = STA_PLL;
1467 if (G.ntp_status & LI_PLUSSEC)
1468 tmx.status |= STA_INS;
1469 if (G.ntp_status & LI_MINUSSEC)
1470 tmx.status |= STA_DEL;
1471 tmx.constant = G.poll_exp - 4;
1472 //tmx.esterror = (u_int32)(clock_jitter * 1e6);
1473 //tmx.maxerror = (u_int32)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
1474 rc = adjtimex(&tmx);
1476 bb_perror_msg_and_die("adjtimex");
1477 /* NB: here kernel returns constant == G.poll_exp, not == G.poll_exp - 4.
1478 * Not sure why. Perhaps it is normal.
1480 VERB3 bb_error_msg("adjtimex:%d freq:%ld offset:%ld constant:%ld status:0x%x",
1481 rc, tmx.freq, tmx.offset, tmx.constant, tmx.status);
1484 /* always gives the same output as above msg */
1485 memset(&tmx, 0, sizeof(tmx));
1486 if (adjtimex(&tmx) < 0)
1487 bb_perror_msg_and_die("adjtimex");
1488 VERB3 bb_error_msg("c adjtimex freq:%ld offset:%ld constant:%ld status:0x%x",
1489 tmx.freq, tmx.offset, tmx.constant, tmx.status);
1492 G.kernel_freq_drift = tmx.freq / 65536;
1493 VERB2 bb_error_msg("update peer:%s, offset:%f, clock drift:%ld ppm",
1494 p->p_dotted, G.last_update_offset, G.kernel_freq_drift);
1496 return 1; /* "ok to increase poll interval" */
1501 * We've got a new reply packet from a peer, process it
1505 retry_interval(void)
1507 /* Local problem, want to retry soon */
1508 unsigned interval, r;
1509 interval = RETRY_INTERVAL;
1511 interval += r % (unsigned)(RETRY_INTERVAL / 4);
1512 VERB3 bb_error_msg("chose retry interval:%u", interval);
1516 poll_interval(int exponent)
1518 unsigned interval, r;
1519 exponent = G.poll_exp + exponent;
1522 interval = 1 << exponent;
1524 interval += ((r & (interval-1)) >> 4) + ((r >> 8) & 1); /* + 1/16 of interval, max */
1525 VERB3 bb_error_msg("chose poll interval:%u (poll_exp:%d exp:%d)", interval, G.poll_exp, exponent);
1528 static NOINLINE void
1529 recv_and_process_peer_pkt(peer_t *p)
1534 double T1, T2, T3, T4;
1536 datapoint_t *datapoint;
1539 /* We can recvfrom here and check from.IP, but some multihomed
1540 * ntp servers reply from their *other IP*.
1541 * TODO: maybe we should check at least what we can: from.port == 123?
1543 size = recv(p->p_fd, &msg, sizeof(msg), MSG_DONTWAIT);
1545 bb_perror_msg("recv(%s) error", p->p_dotted);
1546 if (errno == EHOSTUNREACH || errno == EHOSTDOWN
1547 || errno == ENETUNREACH || errno == ENETDOWN
1548 || errno == ECONNREFUSED || errno == EADDRNOTAVAIL
1551 //TODO: always do this?
1552 interval = retry_interval();
1553 goto set_next_and_close_sock;
1558 if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
1559 bb_error_msg("malformed packet received from %s", p->p_dotted);
1563 if (msg.m_orgtime.int_partl != p->p_xmt_msg.m_xmttime.int_partl
1564 || msg.m_orgtime.fractionl != p->p_xmt_msg.m_xmttime.fractionl
1569 if ((msg.m_status & LI_ALARM) == LI_ALARM
1570 || msg.m_stratum == 0
1571 || msg.m_stratum > NTP_MAXSTRATUM
1573 // TODO: stratum 0 responses may have commands in 32-bit m_refid field:
1574 // "DENY", "RSTR" - peer does not like us at all
1575 // "RATE" - peer is overloaded, reduce polling freq
1576 interval = poll_interval(0);
1577 bb_error_msg("reply from %s: not synced, next query in %us", p->p_dotted, interval);
1578 goto set_next_and_close_sock;
1581 // /* Verify valid root distance */
1582 // if (msg.m_rootdelay / 2 + msg.m_rootdisp >= MAXDISP || p->lastpkt_reftime > msg.m_xmt)
1583 // return; /* invalid header values */
1585 p->lastpkt_status = msg.m_status;
1586 p->lastpkt_stratum = msg.m_stratum;
1587 p->lastpkt_rootdelay = sfp_to_d(msg.m_rootdelay);
1588 p->lastpkt_rootdisp = sfp_to_d(msg.m_rootdisp);
1589 p->lastpkt_refid = msg.m_refid;
1592 * From RFC 2030 (with a correction to the delay math):
1594 * Timestamp Name ID When Generated
1595 * ------------------------------------------------------------
1596 * Originate Timestamp T1 time request sent by client
1597 * Receive Timestamp T2 time request received by server
1598 * Transmit Timestamp T3 time reply sent by server
1599 * Destination Timestamp T4 time reply received by client
1601 * The roundtrip delay and local clock offset are defined as
1603 * delay = (T4 - T1) - (T3 - T2); offset = ((T2 - T1) + (T3 - T4)) / 2
1606 T2 = lfp_to_d(msg.m_rectime);
1607 T3 = lfp_to_d(msg.m_xmttime);
1610 p->lastpkt_recv_time = T4;
1612 VERB5 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
1613 p->datapoint_idx = p->reachable_bits ? (p->datapoint_idx + 1) % NUM_DATAPOINTS : 0;
1614 datapoint = &p->filter_datapoint[p->datapoint_idx];
1615 datapoint->d_recv_time = T4;
1616 datapoint->d_offset = ((T2 - T1) + (T3 - T4)) / 2;
1617 /* The delay calculation is a special case. In cases where the
1618 * server and client clocks are running at different rates and
1619 * with very fast networks, the delay can appear negative. In
1620 * order to avoid violating the Principle of Least Astonishment,
1621 * the delay is clamped not less than the system precision.
1623 p->lastpkt_delay = (T4 - T1) - (T3 - T2);
1624 if (p->lastpkt_delay < G_precision_sec)
1625 p->lastpkt_delay = G_precision_sec;
1626 datapoint->d_dispersion = LOG2D(msg.m_precision_exp) + G_precision_sec;
1627 if (!p->reachable_bits) {
1628 /* 1st datapoint ever - replicate offset in every element */
1630 for (i = 1; i < NUM_DATAPOINTS; i++) {
1631 p->filter_datapoint[i].d_offset = datapoint->d_offset;
1635 p->reachable_bits |= 1;
1636 if ((MAX_VERBOSE && G.verbose) || (option_mask32 & OPT_w)) {
1637 bb_error_msg("reply from %s: reach 0x%02x offset %f delay %f status 0x%02x strat %d refid 0x%08x rootdelay %f",
1640 datapoint->d_offset,
1645 p->lastpkt_rootdelay
1646 /* not shown: m_ppoll, m_precision_exp, m_rootdisp,
1647 * m_reftime, m_orgtime, m_rectime, m_xmttime
1652 /* Muck with statictics and update the clock */
1653 filter_datapoints(p);
1654 q = select_and_cluster();
1658 if (!(option_mask32 & OPT_w)) {
1659 rc = update_local_clock(q);
1660 /* If drift is dangerously large, immediately
1661 * drop poll interval one step down.
1663 if (fabs(q->filter_offset) >= POLLDOWN_OFFSET) {
1664 VERB3 bb_error_msg("offset:%f > POLLDOWN_OFFSET", q->filter_offset);
1669 /* else: no peer selected, rc = -1: we want to poll more often */
1672 /* Adjust the poll interval by comparing the current offset
1673 * with the clock jitter. If the offset is less than
1674 * the clock jitter times a constant, then the averaging interval
1675 * is increased, otherwise it is decreased. A bit of hysteresis
1676 * helps calm the dance. Works best using burst mode.
1679 bb_error_msg("offset:%f POLLADJ_GATE*discipline_jitter:%f poll:%s",
1680 q->filter_offset, POLLADJ_GATE * G.discipline_jitter,
1681 fabs(q->filter_offset) < POLLADJ_GATE * G.discipline_jitter
1685 if (rc > 0 && fabs(q->filter_offset) < POLLADJ_GATE * G.discipline_jitter) {
1686 /* was += G.poll_exp but it is a bit
1687 * too optimistic for my taste at high poll_exp's */
1688 G.polladj_count += MINPOLL;
1689 if (G.polladj_count > POLLADJ_LIMIT) {
1690 G.polladj_count = 0;
1691 if (G.poll_exp < MAXPOLL) {
1693 VERB3 bb_error_msg("polladj: discipline_jitter:%f ++poll_exp=%d",
1694 G.discipline_jitter, G.poll_exp);
1697 VERB3 bb_error_msg("polladj: incr:%d", G.polladj_count);
1700 G.polladj_count -= G.poll_exp * 2;
1701 if (G.polladj_count < -POLLADJ_LIMIT || G.poll_exp >= BIGPOLL) {
1703 G.polladj_count = 0;
1704 if (G.poll_exp > MINPOLL) {
1708 /* Correct p->next_action_time in each peer
1709 * which waits for sending, so that they send earlier.
1710 * Old pp->next_action_time are on the order
1711 * of t + (1 << old_poll_exp) + small_random,
1712 * we simply need to subtract ~half of that.
1714 for (item = G.ntp_peers; item != NULL; item = item->link) {
1715 peer_t *pp = (peer_t *) item->data;
1717 pp->next_action_time -= (1 << G.poll_exp);
1719 VERB3 bb_error_msg("polladj: discipline_jitter:%f --poll_exp=%d",
1720 G.discipline_jitter, G.poll_exp);
1723 VERB3 bb_error_msg("polladj: decr:%d", G.polladj_count);
1728 /* Decide when to send new query for this peer */
1729 interval = poll_interval(0);
1731 set_next_and_close_sock:
1732 set_next(p, interval);
1733 /* We do not expect any more packets from this peer for now.
1734 * Closing the socket informs kernel about it.
1735 * We open a new socket when we send a new query.
1743 #if ENABLE_FEATURE_NTPD_SERVER
1744 static NOINLINE void
1745 recv_and_process_client_pkt(void /*int fd*/)
1749 len_and_sockaddr *to;
1750 struct sockaddr *from;
1752 uint8_t query_status;
1753 l_fixedpt_t query_xmttime;
1755 to = get_sock_lsa(G.listen_fd);
1756 from = xzalloc(to->len);
1758 size = recv_from_to(G.listen_fd, &msg, sizeof(msg), MSG_DONTWAIT, from, &to->u.sa, to->len);
1759 if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
1762 if (errno == EAGAIN)
1764 bb_perror_msg_and_die("recv");
1766 addr = xmalloc_sockaddr2dotted_noport(from);
1767 bb_error_msg("malformed packet received from %s: size %u", addr, (int)size);
1772 query_status = msg.m_status;
1773 query_xmttime = msg.m_xmttime;
1775 /* Build a reply packet */
1776 memset(&msg, 0, sizeof(msg));
1777 msg.m_status = G.stratum < MAXSTRAT ? G.ntp_status : LI_ALARM;
1778 msg.m_status |= (query_status & VERSION_MASK);
1779 msg.m_status |= ((query_status & MODE_MASK) == MODE_CLIENT) ?
1780 MODE_SERVER : MODE_SYM_PAS;
1781 msg.m_stratum = G.stratum;
1782 msg.m_ppoll = G.poll_exp;
1783 msg.m_precision_exp = G_precision_exp;
1784 /* this time was obtained between poll() and recv() */
1785 msg.m_rectime = d_to_lfp(G.cur_time);
1786 msg.m_xmttime = d_to_lfp(gettime1900d()); /* this instant */
1787 if (G.peer_cnt == 0) {
1788 /* we have no peers: "stratum 1 server" mode. reftime = our own time */
1789 G.reftime = G.cur_time;
1791 msg.m_reftime = d_to_lfp(G.reftime);
1792 msg.m_orgtime = query_xmttime;
1793 msg.m_rootdelay = d_to_sfp(G.rootdelay);
1794 //simple code does not do this, fix simple code!
1795 msg.m_rootdisp = d_to_sfp(G.rootdisp);
1796 version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
1797 msg.m_refid = G.refid; // (version > (3 << VERSION_SHIFT)) ? G.refid : G.refid3;
1799 /* We reply from the local address packet was sent to,
1800 * this makes to/from look swapped here: */
1801 do_sendto(G.listen_fd,
1802 /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
1811 /* Upstream ntpd's options:
1813 * -4 Force DNS resolution of host names to the IPv4 namespace.
1814 * -6 Force DNS resolution of host names to the IPv6 namespace.
1815 * -a Require cryptographic authentication for broadcast client,
1816 * multicast client and symmetric passive associations.
1817 * This is the default.
1818 * -A Do not require cryptographic authentication for broadcast client,
1819 * multicast client and symmetric passive associations.
1820 * This is almost never a good idea.
1821 * -b Enable the client to synchronize to broadcast servers.
1823 * Specify the name and path of the configuration file,
1824 * default /etc/ntp.conf
1825 * -d Specify debugging mode. This option may occur more than once,
1826 * with each occurrence indicating greater detail of display.
1828 * Specify debugging level directly.
1830 * Specify the name and path of the frequency file.
1831 * This is the same operation as the "driftfile FILE"
1832 * configuration command.
1833 * -g Normally, ntpd exits with a message to the system log
1834 * if the offset exceeds the panic threshold, which is 1000 s
1835 * by default. This option allows the time to be set to any value
1836 * without restriction; however, this can happen only once.
1837 * If the threshold is exceeded after that, ntpd will exit
1838 * with a message to the system log. This option can be used
1839 * with the -q and -x options. See the tinker command for other options.
1841 * Chroot the server to the directory jaildir. This option also implies
1842 * that the server attempts to drop root privileges at startup
1843 * (otherwise, chroot gives very little additional security).
1844 * You may need to also specify a -u option.
1846 * Specify the name and path of the symmetric key file,
1847 * default /etc/ntp/keys. This is the same operation
1848 * as the "keys FILE" configuration command.
1850 * Specify the name and path of the log file. The default
1851 * is the system log file. This is the same operation as
1852 * the "logfile FILE" configuration command.
1853 * -L Do not listen to virtual IPs. The default is to listen.
1855 * -N To the extent permitted by the operating system,
1856 * run the ntpd at the highest priority.
1858 * Specify the name and path of the file used to record the ntpd
1859 * process ID. This is the same operation as the "pidfile FILE"
1860 * configuration command.
1862 * To the extent permitted by the operating system,
1863 * run the ntpd at the specified priority.
1864 * -q Exit the ntpd just after the first time the clock is set.
1865 * This behavior mimics that of the ntpdate program, which is
1866 * to be retired. The -g and -x options can be used with this option.
1867 * Note: The kernel time discipline is disabled with this option.
1869 * Specify the default propagation delay from the broadcast/multicast
1870 * server to this client. This is necessary only if the delay
1871 * cannot be computed automatically by the protocol.
1873 * Specify the directory path for files created by the statistics
1874 * facility. This is the same operation as the "statsdir DIR"
1875 * configuration command.
1877 * Add a key number to the trusted key list. This option can occur
1880 * Specify a user, and optionally a group, to switch to.
1883 * Add a system variable listed by default.
1884 * -x Normally, the time is slewed if the offset is less than the step
1885 * threshold, which is 128 ms by default, and stepped if above
1886 * the threshold. This option sets the threshold to 600 s, which is
1887 * well within the accuracy window to set the clock manually.
1888 * Note: since the slew rate of typical Unix kernels is limited
1889 * to 0.5 ms/s, each second of adjustment requires an amortization
1890 * interval of 2000 s. Thus, an adjustment as much as 600 s
1891 * will take almost 14 days to complete. This option can be used
1892 * with the -g and -q options. See the tinker command for other options.
1893 * Note: The kernel time discipline is disabled with this option.
1896 /* By doing init in a separate function we decrease stack usage
1899 static NOINLINE void ntp_init(char **argv)
1907 bb_error_msg_and_die(bb_msg_you_must_be_root);
1909 /* Set some globals */
1910 G.stratum = MAXSTRAT;
1912 G.poll_exp = BURSTPOLL; /* speeds up initial sync */
1913 G.last_script_run = G.reftime = G.last_update_recv_time = gettime1900d(); /* sets G.cur_time too */
1917 opt_complementary = "dd:p::wn"; /* d: counter; p: list; -w implies -n */
1918 opts = getopt32(argv,
1920 "wp:S:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
1922 "46aAbgL", /* compat, ignored */
1923 &peers, &G.script_name, &G.verbose);
1924 if (!(opts & (OPT_p|OPT_l)))
1926 // if (opts & OPT_x) /* disable stepping, only slew is allowed */
1927 // G.time_was_stepped = 1;
1930 add_peers(llist_pop(&peers));
1932 /* -l but no peers: "stratum 1 server" mode */
1935 if (!(opts & OPT_n)) {
1936 bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO, argv);
1937 logmode = LOGMODE_NONE;
1939 #if ENABLE_FEATURE_NTPD_SERVER
1942 G.listen_fd = create_and_bind_dgram_or_die(NULL, 123);
1943 socket_want_pktinfo(G.listen_fd);
1944 setsockopt(G.listen_fd, IPPROTO_IP, IP_TOS, &const_IPTOS_LOWDELAY, sizeof(const_IPTOS_LOWDELAY));
1947 /* I hesitate to set -20 prio. -15 should be high enough for timekeeping */
1949 setpriority(PRIO_PROCESS, 0, -15);
1951 /* If network is up, syncronization occurs in ~10 seconds.
1952 * We give "ntpd -q" 10 seconds to get first reply,
1953 * then another 50 seconds to finish syncing.
1955 * I tested ntpd 4.2.6p1 and apparently it never exits
1956 * (will try forever), but it does not feel right.
1957 * The goal of -q is to act like ntpdate: set time
1958 * after a reasonably small period of polling, or fail.
1961 option_mask32 |= OPT_qq;
1978 int ntpd_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
1979 int ntpd_main(int argc UNUSED_PARAM, char **argv)
1987 memset(&G, 0, sizeof(G));
1988 SET_PTR_TO_GLOBALS(&G);
1992 /* If ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
1993 cnt = G.peer_cnt + ENABLE_FEATURE_NTPD_SERVER;
1994 idx2peer = xzalloc(sizeof(idx2peer[0]) * cnt);
1995 pfd = xzalloc(sizeof(pfd[0]) * cnt);
1997 /* Countdown: we never sync before we sent INITIAL_SAMPLES+1
1998 * packets to each peer.
1999 * NB: if some peer is not responding, we may end up sending
2000 * fewer packets to it and more to other peers.
2001 * NB2: sync usually happens using INITIAL_SAMPLES packets,
2002 * since last reply does not come back instantaneously.
2004 cnt = G.peer_cnt * (INITIAL_SAMPLES + 1);
2006 while (!bb_got_signal) {
2012 /* Nothing between here and poll() blocks for any significant time */
2014 nextaction = G.cur_time + 3600;
2017 #if ENABLE_FEATURE_NTPD_SERVER
2018 if (G.listen_fd != -1) {
2019 pfd[0].fd = G.listen_fd;
2020 pfd[0].events = POLLIN;
2024 /* Pass over peer list, send requests, time out on receives */
2025 for (item = G.ntp_peers; item != NULL; item = item->link) {
2026 peer_t *p = (peer_t *) item->data;
2028 if (p->next_action_time <= G.cur_time) {
2029 if (p->p_fd == -1) {
2030 /* Time to send new req */
2032 G.initial_poll_complete = 1;
2034 send_query_to_peer(p);
2036 /* Timed out waiting for reply */
2039 timeout = poll_interval(-2); /* -2: try a bit sooner */
2040 bb_error_msg("timed out waiting for %s, reach 0x%02x, next query in %us",
2041 p->p_dotted, p->reachable_bits, timeout);
2042 set_next(p, timeout);
2046 if (p->next_action_time < nextaction)
2047 nextaction = p->next_action_time;
2050 /* Wait for reply from this peer */
2051 pfd[i].fd = p->p_fd;
2052 pfd[i].events = POLLIN;
2058 timeout = nextaction - G.cur_time;
2061 timeout++; /* (nextaction - G.cur_time) rounds down, compensating */
2063 /* Here we may block */
2064 VERB2 bb_error_msg("poll %us, sockets:%u, poll interval:%us", timeout, i, 1 << G.poll_exp);
2065 nfds = poll(pfd, i, timeout * 1000);
2066 gettime1900d(); /* sets G.cur_time */
2068 if (G.script_name && G.cur_time - G.last_script_run > 11*60) {
2069 /* Useful for updating battery-backed RTC and such */
2070 run_script("periodic", G.last_update_offset);
2071 gettime1900d(); /* sets G.cur_time */
2076 /* Process any received packets */
2078 #if ENABLE_FEATURE_NTPD_SERVER
2079 if (G.listen_fd != -1) {
2080 if (pfd[0].revents /* & (POLLIN|POLLERR)*/) {
2082 recv_and_process_client_pkt(/*G.listen_fd*/);
2083 gettime1900d(); /* sets G.cur_time */
2088 for (; nfds != 0 && j < i; j++) {
2089 if (pfd[j].revents /* & (POLLIN|POLLERR)*/) {
2091 * At init, alarm was set to 10 sec.
2092 * Now we did get a reply.
2093 * Increase timeout to 50 seconds to finish syncing.
2095 if (option_mask32 & OPT_qq) {
2096 option_mask32 &= ~OPT_qq;
2100 recv_and_process_peer_pkt(idx2peer[j]);
2101 gettime1900d(); /* sets G.cur_time */
2104 } /* while (!bb_got_signal) */
2106 kill_myself_with_sig(bb_got_signal);
2114 /*** openntpd-4.6 uses only adjtime, not adjtimex ***/
2116 /*** ntp-4.2.6/ntpd/ntp_loopfilter.c - adjtimex usage ***/
2120 direct_freq(double fp_offset)
2124 * If the kernel is enabled, we need the residual offset to
2125 * calculate the frequency correction.
2127 if (pll_control && kern_enable) {
2128 memset(&ntv, 0, sizeof(ntv));
2131 clock_offset = ntv.offset / 1e9;
2132 #else /* STA_NANO */
2133 clock_offset = ntv.offset / 1e6;
2134 #endif /* STA_NANO */
2135 drift_comp = FREQTOD(ntv.freq);
2137 #endif /* KERNEL_PLL */
2138 set_freq((fp_offset - clock_offset) / (current_time - clock_epoch) + drift_comp);
2144 set_freq(double freq) /* frequency update */
2152 * If the kernel is enabled, update the kernel frequency.
2154 if (pll_control && kern_enable) {
2155 memset(&ntv, 0, sizeof(ntv));
2156 ntv.modes = MOD_FREQUENCY;
2157 ntv.freq = DTOFREQ(drift_comp);
2159 snprintf(tbuf, sizeof(tbuf), "kernel %.3f PPM", drift_comp * 1e6);
2160 report_event(EVNT_FSET, NULL, tbuf);
2162 snprintf(tbuf, sizeof(tbuf), "ntpd %.3f PPM", drift_comp * 1e6);
2163 report_event(EVNT_FSET, NULL, tbuf);
2165 #else /* KERNEL_PLL */
2166 snprintf(tbuf, sizeof(tbuf), "ntpd %.3f PPM", drift_comp * 1e6);
2167 report_event(EVNT_FSET, NULL, tbuf);
2168 #endif /* KERNEL_PLL */
2177 * This code segment works when clock adjustments are made using
2178 * precision time kernel support and the ntp_adjtime() system
2179 * call. This support is available in Solaris 2.6 and later,
2180 * Digital Unix 4.0 and later, FreeBSD, Linux and specially
2181 * modified kernels for HP-UX 9 and Ultrix 4. In the case of the
2182 * DECstation 5000/240 and Alpha AXP, additional kernel
2183 * modifications provide a true microsecond clock and nanosecond
2184 * clock, respectively.
2186 * Important note: The kernel discipline is used only if the
2187 * step threshold is less than 0.5 s, as anything higher can
2188 * lead to overflow problems. This might occur if some misguided
2189 * lad set the step threshold to something ridiculous.
2191 if (pll_control && kern_enable) {
2193 #define MOD_BITS (MOD_OFFSET | MOD_MAXERROR | MOD_ESTERROR | MOD_STATUS | MOD_TIMECONST)
2196 * We initialize the structure for the ntp_adjtime()
2197 * system call. We have to convert everything to
2198 * microseconds or nanoseconds first. Do not update the
2199 * system variables if the ext_enable flag is set. In
2200 * this case, the external clock driver will update the
2201 * variables, which will be read later by the local
2202 * clock driver. Afterwards, remember the time and
2203 * frequency offsets for jitter and stability values and
2204 * to update the frequency file.
2206 memset(&ntv, 0, sizeof(ntv));
2208 ntv.modes = MOD_STATUS;
2211 ntv.modes = MOD_BITS | MOD_NANO;
2212 #else /* STA_NANO */
2213 ntv.modes = MOD_BITS;
2214 #endif /* STA_NANO */
2215 if (clock_offset < 0)
2220 ntv.offset = (int32)(clock_offset * 1e9 + dtemp);
2221 ntv.constant = sys_poll;
2222 #else /* STA_NANO */
2223 ntv.offset = (int32)(clock_offset * 1e6 + dtemp);
2224 ntv.constant = sys_poll - 4;
2225 #endif /* STA_NANO */
2226 ntv.esterror = (u_int32)(clock_jitter * 1e6);
2227 ntv.maxerror = (u_int32)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
2228 ntv.status = STA_PLL;
2231 * Enable/disable the PPS if requested.
2234 if (!(pll_status & STA_PPSTIME))
2235 report_event(EVNT_KERN,
2236 NULL, "PPS enabled");
2237 ntv.status |= STA_PPSTIME | STA_PPSFREQ;
2239 if (pll_status & STA_PPSTIME)
2240 report_event(EVNT_KERN,
2241 NULL, "PPS disabled");
2242 ntv.status &= ~(STA_PPSTIME |
2245 if (sys_leap == LEAP_ADDSECOND)
2246 ntv.status |= STA_INS;
2247 else if (sys_leap == LEAP_DELSECOND)
2248 ntv.status |= STA_DEL;
2252 * Pass the stuff to the kernel. If it squeals, turn off
2253 * the pps. In any case, fetch the kernel offset,
2254 * frequency and jitter.
2256 if (ntp_adjtime(&ntv) == TIME_ERROR) {
2257 if (!(ntv.status & STA_PPSSIGNAL))
2258 report_event(EVNT_KERN, NULL,
2261 pll_status = ntv.status;
2263 clock_offset = ntv.offset / 1e9;
2264 #else /* STA_NANO */
2265 clock_offset = ntv.offset / 1e6;
2266 #endif /* STA_NANO */
2267 clock_frequency = FREQTOD(ntv.freq);
2270 * If the kernel PPS is lit, monitor its performance.
2272 if (ntv.status & STA_PPSTIME) {
2274 clock_jitter = ntv.jitter / 1e9;
2275 #else /* STA_NANO */
2276 clock_jitter = ntv.jitter / 1e6;
2277 #endif /* STA_NANO */
2280 #if defined(STA_NANO) && NTP_API == 4
2282 * If the TAI changes, update the kernel TAI.
2284 if (loop_tai != sys_tai) {
2286 ntv.modes = MOD_TAI;
2287 ntv.constant = sys_tai;
2290 #endif /* STA_NANO */
2292 #endif /* KERNEL_PLL */