#include "libbb.h"
#include <math.h>
#include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
+#include <sys/resource.h> /* setpriority */
#include <sys/timex.h>
#ifndef IPTOS_LOWDELAY
# define IPTOS_LOWDELAY 0x10
/* Verbosity control (max level of -dddd options accepted).
- * max 5 is very talkative (and bloated). 2 is non-bloated,
+ * max 6 is very talkative (and bloated). 3 is non-bloated,
* production level setting.
*/
-#define MAX_VERBOSE 2
+#define MAX_VERBOSE 3
/* High-level description of the algorithm:
* was hibernated, someone set totally wrong date, etc),
* then the time is stepped, all datapoints are discarded,
* and we go back to steady state.
+ *
+ * Made some changes to speed up re-syncing after our clock goes bad
+ * (tested with suspending my laptop):
+ * - if largish offset (>= STEP_THRESHOLD * 8 == 1 sec) is seen
+ * from a peer, schedule next query for this peer soon
+ * without drastically lowering poll interval for everybody.
+ * This makes us collect enough data for step much faster:
+ * e.g. at poll = 10 (1024 secs), step was done within 5 minutes
+ * after first reply which indicated that our clock is 14 seconds off.
+ * - on step, do not discard d_dispersion data of the existing datapoints,
+ * do not clear reachable_bits. This prevents discarding first ~8
+ * datapoints after the step.
*/
-#define RETRY_INTERVAL 5 /* on error, retry in N secs */
+#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 */
+#define INITIAL_SAMPLES 4 /* how many samples do we want for init */
+#define BAD_DELAY_GROWTH 4 /* drop packet if its delay grew by more than this */
/* Clock discipline parameters and constants */
#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) */
+/* If we got largish offset from a peer, cap next query interval
+ * for this peer by this many seconds:
+ */
+#define BIGOFF_INTERVAL (1 << 6)
+/* If offset > discipline_jitter * POLLADJ_GATE, and poll interval is >= 2^BIGPOLL,
+ * then it is decreased _at once_. (If < 2^BIGPOLL, it will be decreased _eventually_).
+ */
+#define BIGPOLL 10 /* 2^10 sec ~= 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
/* 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 grow a counter: += MINPOLL. When counter 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 40 since otherwise I often see poll_exp going *2* steps down)
+ * and when it goes below -POLLADJ_LIMIT, we poll_exp--.
+ * (Bumped from 30 to 40 since otherwise I often see poll_exp going *2* steps down)
*/
#define POLLADJ_LIMIT 40
-/* If offset < POLLADJ_GATE * discipline_jitter, then we can increase
+/* If offset < discipline_jitter * POLLADJ_GATE, then we decide to increase
* poll interval (we think we can't improve timekeeping
* by staying at smaller poll).
*/
#define POLLADJ_GATE 4
+#define TIMECONST_HACK_GATE 2
/* Compromise Allan intercept (sec). doc uses 1500, std ntpd uses 512 */
#define ALLAN 512
/* PLL loop gain */
} msg_t;
typedef struct {
- double d_recv_time;
double d_offset;
+ double d_recv_time;
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;
+ /* when to send new query (if p_fd == -1)
+ * or when receive times out (if p_fd >= 0): */
double next_action_time;
double p_xmttime;
double lastpkt_recv_time;
llist_t *ntp_peers;
#if ENABLE_FEATURE_NTPD_SERVER
int listen_fd;
+# define G_listen_fd (G.listen_fd)
+#else
+# define G_listen_fd (-1)
#endif
unsigned verbose;
unsigned peer_cnt;
#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_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
double last_update_offset; // c.last
double last_update_recv_time; // s.t
double discipline_jitter; // c.jitter
+ /* Since we only compare it with ints, can simplify code
+ * by not making this variable floating point:
+ */
+ unsigned offset_to_jitter_ratio;
//double cluster_offset; // s.offset
//double cluster_jitter; // s.jitter
#if !USING_KERNEL_PLL_LOOP
#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)
+#define VERB6 if (MAX_VERBOSE >= 6 && G.verbose >= 6)
static double LOG2D(int a)
filter_datapoints(peer_t *p)
{
int i, idx;
+ double sum, wavg;
+ datapoint_t *fdp;
+
+#if 0
+/* Simulations have shown that use of *averaged* offset for p->filter_offset
+ * is in fact worse than simply using last received one: with large poll intervals
+ * (>= 2048) averaging code uses offset values which are outdated by hours,
+ * and time/frequency correction goes totally wrong when fed essentially bogus offsets.
+ */
int got_newest;
- double minoff, maxoff, wavg, sum, w;
+ double minoff, maxoff, 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;
+ fdp = p->filter_datapoint;
+
+ minoff = maxoff = fdp[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;
+ if (minoff > fdp[i].d_offset)
+ minoff = fdp[i].d_offset;
+ if (maxoff < fdp[i].d_offset)
+ maxoff = fdp[i].d_offset;
}
- idx = p->datapoint_idx; /* most recent datapoint */
+ idx = p->datapoint_idx; /* most recent datapoint's index */
/* Average offset:
* Drop two outliers and take weighted average of the rest:
* most_recent/2 + older1/4 + older2/8 ... + older5/32 + older6/32
got_newest = 0;
sum = 0;
for (i = 0; i < NUM_DATAPOINTS; i++) {
- VERB4 {
+ VERB5 {
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)
+ fdp[idx].d_offset,
+ fdp[idx].d_dispersion, dispersion(&fdp[idx]),
+ G.cur_time - fdp[idx].d_recv_time,
+ (minoff == fdp[idx].d_offset || maxoff == fdp[idx].d_offset)
? " (outlier by offset)" : ""
);
}
- sum += dispersion(&p->filter_datapoint[idx]) / (2 << i);
+ sum += dispersion(&fdp[idx]) / (2 << i);
- if (minoff == p->filter_datapoint[idx].d_offset) {
+ if (minoff == fdp[idx].d_offset) {
minoff -= 1; /* so that we don't match it ever again */
} else
- if (maxoff == p->filter_datapoint[idx].d_offset) {
+ if (maxoff == fdp[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;
+ oldest_off = fdp[idx].d_offset;
+ oldest_age = G.cur_time - fdp[idx].d_recv_time;
if (!got_newest) {
got_newest = 1;
newest_off = oldest_off;
}
p->filter_offset = wavg;
+#else
+
+ fdp = p->filter_datapoint;
+ idx = p->datapoint_idx; /* most recent datapoint's index */
+
+ /* filter_offset: simply use the most recent value */
+ p->filter_offset = fdp[idx].d_offset;
+
+ /* n-1
+ * --- dispersion(i)
+ * filter_dispersion = \ -------------
+ * / (i+1)
+ * --- 2
+ * i=0
+ */
+ wavg = 0;
+ sum = 0;
+ for (i = 0; i < NUM_DATAPOINTS; i++) {
+ sum += dispersion(&fdp[idx]) / (2 << i);
+ wavg += fdp[idx].d_offset;
+ idx = (idx - 1) & (NUM_DATAPOINTS - 1);
+ }
+ wavg /= NUM_DATAPOINTS;
+ p->filter_dispersion = sum;
+#endif
+
/* +----- -----+ ^ 1/2
* | n-1 |
* | --- |
*/
sum = 0;
for (i = 0; i < NUM_DATAPOINTS; i++) {
- sum += SQUARE(wavg - p->filter_datapoint[i].d_offset);
+ sum += SQUARE(wavg - fdp[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,
+ VERB4 bb_error_msg("filter offset:%+f disp:%f jitter:%f",
+ p->filter_offset,
p->filter_dispersion,
p->filter_jitter);
}
int i;
bool small_ofs = fabs(offset) < 16 * STEP_THRESHOLD;
+ /* Used to set p->filter_datapoint[i].d_dispersion = MAXDISP
+ * and clear reachable bits, but this proved to be too agressive:
+ * after step (tested with suspinding laptop for ~30 secs),
+ * this caused all previous data to be considered invalid,
+ * making us needing to collect full ~8 datapoins per peer
+ * after step in order to start trusting them.
+ * In turn, this was making poll interval decrease even after
+ * step was done. (Poll interval decreases already before step
+ * in this scenario, because we see large offsets and end up with
+ * no good peer to select).
+ */
+
for (i = 0; i < NUM_DATAPOINTS; i++) {
if (small_ofs) {
p->filter_datapoint[i].d_recv_time += 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;
+ /*p->filter_datapoint[i].d_dispersion = MAXDISP;*/
}
}
if (small_ofs) {
p->lastpkt_recv_time += offset;
} else {
- p->reachable_bits = 0;
+ /*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);
+ VERB6 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
}
static void
free(local_lsa);
}
+ /* Emit message _before_ attempted send. Think of a very short
+ * roundtrip networks: we need to go back to recv loop ASAP,
+ * to reduce delay. Printing messages after send works against that.
+ */
+ VERB1 bb_error_msg("sending query to %s", p->p_dotted);
+
/*
* Send out a random 64-bit number as our transmit time. The NTP
* server will copy said number into the originate field on the
p->p_xmt_msg.m_xmttime.fractionl = random();
p->p_xmttime = gettime1900d();
+ /* Were doing it only if sendto worked, but
+ * loss of sync detection needs reachable_bits updated
+ * even if sending fails *locally*:
+ * "network is unreachable" because cable was pulled?
+ * We still need to declare "unsync" if this condition persists.
+ */
+ p->reachable_bits <<= 1;
+
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;
+ /*
+ * We know that we sent nothing.
+ * We can retry *soon* without fearing
+ * that we are flooding the peer.
+ */
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
+ * to be started 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.
char *argv[3];
char *env1, *env2, *env3, *env4;
+ G.last_script_run = G.cur_time;
+
if (!G.script_name)
return;
free(env2);
free(env3);
free(env4);
-
- G.last_script_run = G.cur_time;
}
static NOINLINE void
VERB2 {
tval = tvc.tv_sec;
- strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", localtime(&tval));
+ strftime_YYYYMMDDHHMMSS(buf, sizeof(buf), &tval);
bb_error_msg("current time is %s.%06u", buf, (unsigned)tvc.tv_usec);
}
tval = tvn.tv_sec;
- strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", localtime(&tval));
+ strftime_YYYYMMDDHHMMSS(buf, sizeof(buf), &tval);
bb_error_msg("setting time to %s.%06u (offset %+fs)", buf, (unsigned)tvn.tv_usec, offset);
/* Correct various fields which contain time-relative values: */
+ /* Globals: */
+ G.cur_time += offset;
+ G.last_update_recv_time += offset;
+ G.last_script_run += offset;
+
/* 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;
//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;
+ if (pp->p_fd >= 0) {
+ /* We wait for reply from this peer too.
+ * But due to step we are doing, reply's data is no longer
+ * useful (in fact, it'll be bogus). Stop waiting for it.
+ */
+ close(pp->p_fd);
+ pp->p_fd = -1;
+ set_next(pp, RETRY_INTERVAL);
+ }
}
- /* Globals: */
- G.cur_time += offset;
- G.last_update_recv_time += offset;
- G.last_script_run += offset;
}
{
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);
+ VERB4 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);
+ VERB4 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);
+ VERB4 bb_error_msg("peer %s unfit for selection: root distance too high", p->p_dotted);
return 0;
}
//TODO
continue;
}
- VERB4 bb_error_msg("interval: [%f %f %f] %s",
+ VERB5 bb_error_msg("interval: [%f %f %f] %s",
offset - rd,
offset,
offset + rd,
}
num_candidates = num_points / 3;
if (num_candidates == 0) {
- VERB3 bb_error_msg("no valid datapoints, no peer selected");
+ VERB3 bb_error_msg("no valid datapoints%s", ", no peer selected");
return NULL;
}
//TODO: sorting does not seem to be done in reference code
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);
+ VERB3 bb_error_msg("falsetickers:%d, candidates:%d%s",
+ num_falsetickers, num_candidates,
+ ", no peer selected");
return NULL;
}
}
- VERB3 bb_error_msg("selected interval: [%f, %f]; candidates:%d falsetickers:%d",
+ VERB4 bb_error_msg("selected interval: [%f, %f]; candidates:%d falsetickers:%d",
low, high, num_candidates, num_falsetickers);
/* Clustering */
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",
+ VERB5 bb_error_msg("survivor[%d] metric:%f peer:%s",
num_survivors, survivor[num_survivors].metric, p->p_dotted);
num_survivors++;
}
* is acceptable.
*/
if (num_survivors < MIN_SELECTED) {
- VERB3 bb_error_msg("num_survivors %d < %d, no peer selected",
- num_survivors, MIN_SELECTED);
+ VERB3 bb_error_msg("survivors:%d%s",
+ num_survivors,
+ ", no peer selected");
return NULL;
}
double min_jitter = min_jitter;
if (num_survivors <= MIN_CLUSTERED) {
- VERB3 bb_error_msg("num_survivors %d <= %d, not discarding more",
+ VERB4 bb_error_msg("num_survivors %d <= %d, not discarding more",
num_survivors, MIN_CLUSTERED);
break;
}
max_selection_jitter = selection_jitter_sq;
max_idx = i;
}
- VERB5 bb_error_msg("survivor %d selection_jitter^2:%f",
+ VERB6 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",
+ VERB5 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
* 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",
+ VERB4 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);
+ VERB6 bb_error_msg("dropping survivor %d", max_idx);
num_survivors--;
while (max_idx < num_survivors) {
survivor[max_idx] = survivor[max_idx + 1];
/* 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");
+ VERB5 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",
+ VERB4 bb_error_msg("selected peer %s filter_offset:%+f age:%f",
p->p_dotted,
p->filter_offset,
G.cur_time - p->lastpkt_recv_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",
+ VERB4 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;
* 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);
+ VERB3 bb_error_msg("update from %s: same or older datapoint, not using it",
+ p->p_dotted);
return 0; /* "leave poll interval as is" */
}
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",
+ VERB4 bb_error_msg("measuring drift, datapoint ignored, %f sec remains",
WATCH_THRESHOLD - since_last_update);
return 0; /* "leave poll interval as is" */
}
* offset exceeds the step threshold and when it does not.
*/
if (abs_offset > STEP_THRESHOLD) {
+#if 0
+ double remains;
+
+// This "spike state" seems to be useless, peer selection already drops
+// occassional "bad" datapoints. If we are here, there were _many_
+// large offsets. When a few first large offsets are seen,
+// we end up in "no valid datapoints, no peer selected" state.
+// Only when enough of them are seen (which means it's not a fluke),
+// we end up here. Looks like _our_ clock is off.
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);
+ VERB3 bb_error_msg("update from %s: offset:%+f, spike%s",
+ p->p_dotted, offset,
+ "");
G.discipline_state = STATE_SPIK;
return -1; /* "decrease poll interval" */
/* 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);
+ remains = WATCH_THRESHOLD - since_last_update;
+ if (remains > 0) {
+ VERB3 bb_error_msg("update from %s: offset:%+f, spike%s",
+ p->p_dotted, offset,
+ ", datapoint ignored");
return -1; /* "decrease poll interval" */
}
/* fall through: we need to step */
} /* switch */
+#endif
/* Step the time and clamp down the poll interval.
*
* is always suppressed, even at the longer poll
* intervals.
*/
- VERB3 bb_error_msg("stepping time by %+f; poll_exp=MINPOLL", offset);
+ VERB4 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. */
run_script("step", offset);
+ recv_time += 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);
+ abs_offset = offset = 0;
+ set_new_values(STATE_SYNC, offset, 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);
+ VERB4 bb_error_msg("small offset:%+f, disabling burst mode", offset);
G.polladj_count = 0;
G.poll_exp = MINPOLL;
}
etemp = SQUARE(G.discipline_jitter);
dtemp = SQUARE(offset - G.last_update_offset);
G.discipline_jitter = SQRT(etemp + (dtemp - etemp) / AVG);
- if (G.discipline_jitter < G_precision_sec)
- G.discipline_jitter = G_precision_sec;
- VERB3 bb_error_msg("discipline jitter=%f", G.discipline_jitter);
switch (G.discipline_state) {
case STATE_NSET:
#else
set_new_values(STATE_SYNC, offset, recv_time);
#endif
- VERB3 bb_error_msg("transitioning to FREQ, datapoint ignored");
+ VERB4 bb_error_msg("transitioning to FREQ, datapoint ignored");
return 0; /* "leave poll interval as is" */
#if 0 /* this is dead code for now */
}
}
+ if (G.discipline_jitter < G_precision_sec)
+ G.discipline_jitter = G_precision_sec;
+ G.offset_to_jitter_ratio = abs_offset / G.discipline_jitter;
+
G.reftime = G.cur_time;
G.ntp_status = p->lastpkt_status;
G.refid = p->lastpkt_refid;
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);
+ VERB4 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
+ * By this time, freq_drift and offset are set
* to values suitable for adjtimex.
*/
#if !USING_KERNEL_PLL_LOOP
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",
+ VERB4 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 {
+ VERB4 {
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);
+ bb_error_msg("p adjtimex freq:%ld offset:%+ld status:0x%x tc:%ld",
+ tmx.freq, tmx.offset, tmx.status, tmx.constant);
}
memset(&tmx, 0, sizeof(tmx));
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.offset = (offset * 1000000); /* usec */
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);
+ /* EXPERIMENTAL.
+ * The below if statement should be unnecessary, but...
+ * It looks like Linux kernel's PLL is far too gentle in changing
+ * tmx.freq in response to clock offset. Offset keeps growing
+ * and eventually we fall back to smaller poll intervals.
+ * We can make correction more agressive (about x2) by supplying
+ * PLL time constant which is one less than the real one.
+ * To be on a safe side, let's do it only if offset is significantly
+ * larger than jitter.
+ */
+ if (tmx.constant > 0 && G.offset_to_jitter_ratio >= TIMECONST_HACK_GATE)
+ tmx.constant--;
+
+ //tmx.esterror = (uint32_t)(clock_jitter * 1e6);
+ //tmx.maxerror = (uint32_t)((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
+ VERB4 bb_error_msg("adjtimex:%d freq:%ld offset:%+ld status:0x%x",
+ rc, tmx.freq, tmx.offset, tmx.status);
G.kernel_freq_drift = tmx.freq / 65536;
- VERB2 bb_error_msg("update peer:%s, offset:%+f, jitter:%f, clock drift:%+.3f ppm",
- p->p_dotted, G.last_update_offset, G.discipline_jitter, (double)tmx.freq / 65536);
+ VERB2 bb_error_msg("update from:%s offset:%+f jitter:%f clock drift:%+.3fppm tc:%d",
+ p->p_dotted, offset, G.discipline_jitter, (double)tmx.freq / 65536, (int)tmx.constant);
return 1; /* "ok to increase poll interval" */
}
interval = RETRY_INTERVAL;
r = random();
interval += r % (unsigned)(RETRY_INTERVAL / 4);
- VERB3 bb_error_msg("chose retry interval:%u", interval);
+ VERB4 bb_error_msg("chose retry interval:%u", interval);
return interval;
}
static unsigned
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);
+ VERB4 bb_error_msg("chose poll interval:%u (poll_exp:%d exp:%d)", interval, G.poll_exp, exponent);
return interval;
}
static NOINLINE void
ssize_t size;
msg_t msg;
double T1, T2, T3, T4;
+ double dv, offset;
unsigned interval;
datapoint_t *datapoint;
peer_t *q;
+ offset = 0;
+
/* 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?
) {
//TODO: always do this?
interval = retry_interval();
- goto set_next_and_close_sock;
+ goto set_next_and_ret;
}
xfunc_die();
}
if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
bb_error_msg("malformed packet received from %s", p->p_dotted);
- goto bail;
+ return;
}
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;
+ /* Somebody else's packet */
+ return;
}
+ /* 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;
+
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;
+ bb_error_msg("reply from %s: peer is unsynced", p->p_dotted);
+ goto pick_normal_interval;
}
// /* Verify valid root distance */
T4 = G.cur_time;
p->lastpkt_recv_time = T4;
+ VERB6 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
- 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.
*/
+ dv = p->lastpkt_delay;
p->lastpkt_delay = (T4 - T1) - (T3 - T2);
if (p->lastpkt_delay < G_precision_sec)
p->lastpkt_delay = G_precision_sec;
+ /*
+ * If this packet's delay is much bigger than the last one,
+ * it's better to just ignore it than use its much less precise value.
+ */
+ if (p->reachable_bits && p->lastpkt_delay > dv * BAD_DELAY_GROWTH) {
+ bb_error_msg("reply from %s: delay %f is too high, ignoring", p->p_dotted, p->lastpkt_delay);
+ goto pick_normal_interval;
+ }
+
+ 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 = offset = ((T2 - T1) + (T3 - T4)) / 2;
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;
+ for (i = 0; i < NUM_DATAPOINTS; i++) {
+ p->filter_datapoint[i].d_offset = 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",
+ bb_error_msg("reply from %s: offset:%+f delay:%f status:0x%02x strat:%d refid:0x%08x rootdelay:%f reach:0x%02x",
p->p_dotted,
- p->reachable_bits,
- datapoint->d_offset,
+ offset,
p->lastpkt_delay,
p->lastpkt_status,
p->lastpkt_stratum,
p->lastpkt_refid,
- p->lastpkt_rootdelay
+ p->lastpkt_rootdelay,
+ p->reachable_bits
/* not shown: m_ppoll, m_precision_exp, m_rootdisp,
* m_reftime, m_orgtime, m_rectime, m_xmttime
*/
* drop poll interval one step down.
*/
if (fabs(q->filter_offset) >= POLLDOWN_OFFSET) {
- VERB3 bb_error_msg("offset:%+f > POLLDOWN_OFFSET", q->filter_offset);
+ VERB4 bb_error_msg("offset:%+f > POLLDOWN_OFFSET", q->filter_offset);
goto poll_down;
}
}
* 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) {
+ if (rc > 0 && G.offset_to_jitter_ratio <= POLLADJ_GATE) {
/* was += G.poll_exp but it is a bit
* too optimistic for my taste at high poll_exp's */
G.polladj_count += MINPOLL;
G.polladj_count = 0;
if (G.poll_exp < MAXPOLL) {
G.poll_exp++;
- VERB3 bb_error_msg("polladj: discipline_jitter:%f ++poll_exp=%d",
+ VERB4 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);
+ VERB4 bb_error_msg("polladj: incr:%d", G.polladj_count);
}
} else {
G.polladj_count -= G.poll_exp * 2;
if (pp->p_fd < 0)
pp->next_action_time -= (1 << G.poll_exp);
}
- VERB3 bb_error_msg("polladj: discipline_jitter:%f --poll_exp=%d",
+ VERB4 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);
+ VERB4 bb_error_msg("polladj: decr:%d", G.polladj_count);
}
}
}
/* Decide when to send new query for this peer */
+ pick_normal_interval:
interval = poll_interval(0);
+ if (fabs(offset) >= STEP_THRESHOLD * 8 && interval > BIGOFF_INTERVAL) {
+ /* If we are synced, offsets are less than STEP_THRESHOLD,
+ * or at the very least not much larger than it.
+ * Now we see a largish one.
+ * Either this peer is feeling bad, or packet got corrupted,
+ * or _our_ clock is wrong now and _all_ peers will show similar
+ * largish offsets too.
+ * I observed this with laptop suspend stopping clock.
+ * In any case, it makes sense to make next request soonish:
+ * cases 1 and 2: get a better datapoint,
+ * case 3: allows to resync faster.
+ */
+ interval = BIGOFF_INTERVAL;
+ }
- set_next_and_close_sock:
+ set_next_and_ret:
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
uint8_t query_status;
l_fixedpt_t query_xmttime;
- to = get_sock_lsa(G.listen_fd);
+ 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);
+ 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) {
/* Build a reply packet */
memset(&msg, 0, sizeof(msg));
- msg.m_status = G.stratum < MAXSTRAT ? G.ntp_status : LI_ALARM;
+ msg.m_status = G.stratum < MAXSTRAT ? (G.ntp_status & LI_MASK) : LI_ALARM;
msg.m_status |= (query_status & VERSION_MASK);
msg.m_status |= ((query_status & MODE_MASK) == MODE_CLIENT) ?
- MODE_SERVER : MODE_SYM_PAS;
+ MODE_SERVER : MODE_SYM_PAS;
msg.m_stratum = G.stratum;
msg.m_ppoll = G.poll_exp;
msg.m_precision_exp = G_precision_exp;
/* We reply from the local address packet was sent to,
* this makes to/from look swapped here: */
- do_sendto(G.listen_fd,
+ do_sendto(G_listen_fd,
/*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
&msg, size);
logmode = LOGMODE_NONE;
}
#if ENABLE_FEATURE_NTPD_SERVER
- G.listen_fd = -1;
+ 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));
+ 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 */
*/
cnt = G.peer_cnt * (INITIAL_SAMPLES + 1);
+ write_pidfile(CONFIG_PID_FILE_PATH "/ntpd.pid");
+
while (!bb_got_signal) {
llist_t *item;
unsigned i, j;
i = 0;
#if ENABLE_FEATURE_NTPD_SERVER
- if (G.listen_fd != -1) {
- pfd[0].fd = G.listen_fd;
+ if (G_listen_fd != -1) {
+ pfd[0].fd = G_listen_fd;
pfd[0].events = POLLIN;
i++;
}
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);
+ VERB2 {
+ if (i > (ENABLE_FEATURE_NTPD_SERVER && G_listen_fd != -1)) {
+ /* We wait for at least one reply.
+ * Poll for it, without wasting time for message.
+ * Since replies often come under 1 second, this also
+ * reduces clutter in logs.
+ */
+ nfds = poll(pfd, i, 1000);
+ if (nfds != 0)
+ goto did_poll;
+ if (--timeout <= 0)
+ goto did_poll;
+ }
+ bb_error_msg("poll:%us sockets:%u interval:%us", timeout, i, 1 << G.poll_exp);
+ }
nfds = poll(pfd, i, timeout * 1000);
+ did_poll:
gettime1900d(); /* sets G.cur_time */
if (nfds <= 0) {
- if (G.script_name && G.cur_time - G.last_script_run > 11*60) {
+ if (!bb_got_signal /* poll wasn't interrupted by a signal */
+ && 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;
+ goto check_unsync;
}
/* Process any received packets */
gettime1900d(); /* sets G.cur_time */
}
}
+
+ check_unsync:
+ if (G.ntp_peers && G.stratum != MAXSTRAT) {
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
+ peer_t *p = (peer_t *) item->data;
+ if (p->reachable_bits)
+ goto have_reachable_peer;
+ }
+ /* No peer responded for last 8 packets, panic */
+ G.polladj_count = 0;
+ G.poll_exp = MINPOLL;
+ G.stratum = MAXSTRAT;
+ run_script("unsync", 0.0);
+ have_reachable_peer: ;
+ }
} /* while (!bb_got_signal) */
+ remove_pidfile(CONFIG_PID_FILE_PATH "/ntpd.pid");
kill_myself_with_sig(bb_got_signal);
}
if (pps_enable) {
if (!(pll_status & STA_PPSTIME))
report_event(EVNT_KERN,
- NULL, "PPS enabled");
+ 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);
+ NULL, "PPS disabled");
+ ntv.status &= ~(STA_PPSTIME | STA_PPSFREQ);
}
if (sys_leap == LEAP_ADDSECOND)
ntv.status |= STA_INS;
if (ntp_adjtime(&ntv) == TIME_ERROR) {
if (!(ntv.status & STA_PPSSIGNAL))
report_event(EVNT_KERN, NULL,
- "PPS no signal");
+ "PPS no signal");
}
pll_status = ntv.status;
#ifdef STA_NANO
projects / platform / upstream / busybox.git / blobdiff