Boolean adjFreq(clockid_t clkid, int adj)
{
struct timex tx;
int err;
if (adj > ADJ_FREQ_MAX)
adj = ADJ_FREQ_MAX;
else if (adj < -ADJ_FREQ_MAX)
adj = -ADJ_FREQ_MAX;
memset(&tx, 0, sizeof(tx));
tx.modes = ADJ_FREQUENCY;
tx.freq = (long) (adj * 65.536);
err = clock_adjtime(clkid, &tx);
if (err < 0) {
ERROR("failed adjust the PTP clock: %s\n", strerror(errno));
return FALSE;
}
NOTIFY("adjusted system clock by %d\n", adj);
return TRUE;
}
/* wake up when the system time changes underneath us */
static int sntp_clock_watch_setup(SNTPContext *sntp) {
struct itimerspec its = { .it_value.tv_sec = TIME_T_MAX };
_cleanup_close_ int fd = -1;
sd_event *e;
sd_event_source *source;
int r;
assert(sntp);
assert(sntp->event_receive);
fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
if (fd < 0) {
log_error("Failed to create timerfd: %m");
return -errno;
}
if (timerfd_settime(fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) {
log_error("Failed to set up timerfd: %m");
return -errno;
}
e = sd_event_source_get_event(sntp->event_receive);
r = sd_event_add_io(e, &source, fd, EPOLLIN, sntp_clock_watch, sntp);
if (r < 0) {
log_error("Failed to create clock watch event source: %s", strerror(-r));
return r;
}
sd_event_source_unref(sntp->event_clock_watch);
sntp->event_clock_watch = source;
if (sntp->clock_watch_fd >= 0)
close(sntp->clock_watch_fd);
sntp->clock_watch_fd = fd;
fd = -1;
return 0;
}
static int sntp_adjust_clock(SNTPContext *sntp, double offset, int leap_sec) {
struct timex tmx = {};
int r;
/*
* For small deltas, tell the kernel to gradually adjust the system
* clock to the NTP time, larger deltas are just directly set.
*
* Clear STA_UNSYNC, it will enable the kernel's 11-minute mode, which
* syncs the system time periodically to the hardware clock.
*/
if (offset < NTP_MAX_ADJUST && offset > -NTP_MAX_ADJUST) {
tmx.modes |= ADJ_STATUS | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
tmx.status = STA_PLL;
tmx.offset = offset * 1000 * 1000;
tmx.constant = log2i(sntp->poll_interval_usec / USEC_PER_SEC) - 6;
tmx.maxerror = 0;
tmx.esterror = 0;
log_debug(" adjust (slew): %+f sec\n", (double)tmx.offset / USEC_PER_SEC);
} else {
tmx.modes = ADJ_SETOFFSET;
d_to_tv(offset, &tmx.time);
sntp->jumped = true;
log_debug(" adjust (jump): %+f sec\n", tv_to_d(&tmx.time));
}
switch (leap_sec) {
case 1:
tmx.status |= STA_INS;
break;
case -1:
tmx.status |= STA_DEL;
break;
}
r = clock_adjtime(CLOCK_REALTIME, &tmx);
if (r < 0)
return r;
log_debug(" status : %04i %s\n"
" time now : %li.%06li\n"
" constant : %li\n"
" offset : %+f sec\n"
" freq offset : %+li (%+.3f ppm)\n",
tmx.status, tmx.status & STA_UNSYNC ? "" : "sync",
tmx.time.tv_sec, tmx.time.tv_usec,
tmx.constant,
(double)tmx.offset / USEC_PER_SEC,
tmx.freq, (double)tmx.freq / 65536);
return 0;
}
static bool sntp_sample_spike_detection(SNTPContext *sntp, double offset, double delay) {
unsigned int i, idx_cur, idx_new, idx_min;
double jitter;
double j;
/* store the current data in our samples array */
idx_cur = sntp->samples_idx;
idx_new = (idx_cur + 1) % ELEMENTSOF(sntp->samples);
sntp->samples_idx = idx_new;
sntp->samples[idx_new].offset = offset;
sntp->samples[idx_new].delay = delay;
sntp->packet_count++;
jitter = sntp->samples_jitter;
/* calculate new jitter value from the RMS differences relative to the lowest delay sample */
for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(sntp->samples); i++)
if (sntp->samples[i].delay > 0 && sntp->samples[i].delay < sntp->samples[idx_min].delay)
idx_min = i;
j = 0;
for (i = 0; i < ELEMENTSOF(sntp->samples); i++)
j += square(sntp->samples[i].offset - sntp->samples[idx_min].offset);
sntp->samples_jitter = sqrt(j / (ELEMENTSOF(sntp->samples) - 1));
/* ignore samples when resyncing */
if (sntp->poll_resync)
return false;
/* always accept offset if we are farther off than the round-trip delay */
if (fabs(offset) > delay)
return false;
/* we need a few samples before looking at them */
if (sntp->packet_count < 4)
return false;
/* do not accept anything worse than the maximum possible error of the best sample */
if (fabs(offset) > sntp->samples[idx_min].delay)
return true;
/* compare the difference between the current offset to the previous offset and jitter */
return fabs(offset - sntp->samples[idx_cur].offset) > 3 * jitter;
}
int main(int argc, char *argv[])
{
struct ptp_clock_caps caps;
struct ptp_extts_event event;
struct ptp_extts_request extts_request;
struct ptp_perout_request perout_request;
struct timespec ts;
struct timex tx;
static timer_t timerid;
struct itimerspec timeout;
struct sigevent sigevent;
char *progname;
int c, cnt, fd;
char *device = DEVICE;
clockid_t clkid;
int adjfreq = 0x7fffffff;
int adjtime = 0;
int capabilities = 0;
int extts = 0;
int gettime = 0;
int oneshot = 0;
int periodic = 0;
int perout = -1;
int pps = -1;
int settime = 0;
progname = strrchr(argv[0], '/');
progname = progname ? 1+progname : argv[0];
while (EOF != (c = getopt(argc, argv, "a:A:cd:e:f:ghp:P:st:v"))) {
switch (c) {
case 'a':
oneshot = atoi(optarg);
break;
case 'A':
periodic = atoi(optarg);
break;
case 'c':
capabilities = 1;
break;
case 'd':
device = optarg;
break;
case 'e':
extts = atoi(optarg);
break;
case 'f':
adjfreq = atoi(optarg);
break;
case 'g':
gettime = 1;
break;
case 'p':
perout = atoi(optarg);
break;
case 'P':
pps = atoi(optarg);
break;
case 's':
settime = 1;
break;
case 't':
adjtime = atoi(optarg);
break;
case 'h':
usage(progname);
return 0;
case '?':
default:
usage(progname);
return -1;
}
}
fd = open(device, O_RDWR);
if (fd < 0) {
fprintf(stderr, "opening %s: %s\n", device, strerror(errno));
return -1;
}
clkid = get_clockid(fd);
if (CLOCK_INVALID == clkid) {
fprintf(stderr, "failed to read clock id\n");
return -1;
}
if (capabilities) {
if (ioctl(fd, PTP_CLOCK_GETCAPS, &caps)) {
perror("PTP_CLOCK_GETCAPS");
} else {
printf("capabilities:\n"
" %d maximum frequency adjustment (ppb)\n"
" %d programmable alarms\n"
" %d external time stamp channels\n"
" %d programmable periodic signals\n"
" %d pulse per second\n",
caps.max_adj,
caps.n_alarm,
caps.n_ext_ts,
caps.n_per_out,
caps.pps);
}
}
if (0x7fffffff != adjfreq) {
memset(&tx, 0, sizeof(tx));
tx.modes = ADJ_FREQUENCY;
tx.freq = ppb_to_scaled_ppm(adjfreq);
if (clock_adjtime(clkid, &tx)) {
perror("clock_adjtime");
} else {
puts("frequency adjustment okay");
}
}
if (adjtime) {
memset(&tx, 0, sizeof(tx));
tx.modes = ADJ_SETOFFSET;
tx.time.tv_sec = adjtime;
tx.time.tv_usec = 0;
if (clock_adjtime(clkid, &tx) < 0) {
perror("clock_adjtime");
} else {
puts("time shift okay");
}
}
if (gettime) {
if (clock_gettime(clkid, &ts)) {
perror("clock_gettime");
} else {
printf("clock time: %ld.%09ld or %s",
ts.tv_sec, ts.tv_nsec, ctime(&ts.tv_sec));
}
}
if (settime) {
clock_gettime(CLOCK_REALTIME, &ts);
if (clock_settime(clkid, &ts)) {
perror("clock_settime");
} else {
puts("set time okay");
}
}
if (extts) {
memset(&extts_request, 0, sizeof(extts_request));
extts_request.index = 0;
extts_request.flags = PTP_ENABLE_FEATURE;
if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
perror("PTP_EXTTS_REQUEST");
extts = 0;
} else {
puts("external time stamp request okay");
}
for (; extts; extts--) {
cnt = read(fd, &event, sizeof(event));
if (cnt != sizeof(event)) {
perror("read");
break;
}
printf("event index %u at %lld.%09u\n", event.index,
event.t.sec, event.t.nsec);
fflush(stdout);
}
/* Disable the feature again. */
extts_request.flags = 0;
if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
perror("PTP_EXTTS_REQUEST");
}
}
if (oneshot) {
install_handler(SIGALRM, handle_alarm);
/* Create a timer. */
sigevent.sigev_notify = SIGEV_SIGNAL;
sigevent.sigev_signo = SIGALRM;
if (timer_create(clkid, &sigevent, &timerid)) {
perror("timer_create");
return -1;
}
/* Start the timer. */
memset(&timeout, 0, sizeof(timeout));
timeout.it_value.tv_sec = oneshot;
if (timer_settime(timerid, 0, &timeout, NULL)) {
perror("timer_settime");
return -1;
}
pause();
timer_delete(timerid);
}
if (periodic) {
install_handler(SIGALRM, handle_alarm);
/* Create a timer. */
sigevent.sigev_notify = SIGEV_SIGNAL;
sigevent.sigev_signo = SIGALRM;
if (timer_create(clkid, &sigevent, &timerid)) {
perror("timer_create");
return -1;
}
/* Start the timer. */
memset(&timeout, 0, sizeof(timeout));
timeout.it_interval.tv_sec = periodic;
timeout.it_value.tv_sec = periodic;
if (timer_settime(timerid, 0, &timeout, NULL)) {
perror("timer_settime");
return -1;
}
while (1) {
pause();
}
timer_delete(timerid);
}
if (perout >= 0) {
if (clock_gettime(clkid, &ts)) {
perror("clock_gettime");
return -1;
}
memset(&perout_request, 0, sizeof(perout_request));
perout_request.index = 0;
perout_request.start.sec = ts.tv_sec + 2;
perout_request.start.nsec = 0;
perout_request.period.sec = 0;
perout_request.period.nsec = perout;
if (ioctl(fd, PTP_PEROUT_REQUEST, &perout_request)) {
perror("PTP_PEROUT_REQUEST");
} else {
puts("periodic output request okay");
}
}
if (pps != -1) {
int enable = pps ? 1 : 0;
if (ioctl(fd, PTP_ENABLE_PPS, enable)) {
perror("PTP_ENABLE_PPS");
} else {
puts("pps for system time request okay");
}
}
close(fd);
return 0;
}
int main(int argc, char *argv[])
{
struct ptp_clock_caps caps;
struct ptp_extts_event event;
struct ptp_extts_request extts_request;
struct ptp_perout_request perout_request;
struct ptp_pin_desc desc;
struct timespec ts;
struct timex tx;
static timer_t timerid;
struct itimerspec timeout;
struct sigevent sigevent;
struct ptp_clock_time *pct;
struct ptp_sys_offset *sysoff;
char *progname;
unsigned int i;
int c, cnt, fd;
char *device = DEVICE;
clockid_t clkid;
int adjfreq = 0x7fffffff;
int adjtime = 0;
int capabilities = 0;
int extts = 0;
int gettime = 0;
int index = 0;
int list_pins = 0;
int oneshot = 0;
int pct_offset = 0;
int n_samples = 0;
int periodic = 0;
int perout = -1;
int pin_index = -1, pin_func;
int pps = -1;
int seconds = 0;
int settime = 0;
int64_t t1, t2, tp;
int64_t interval, offset;
progname = strrchr(argv[0], '/');
progname = progname ? 1+progname : argv[0];
while (EOF != (c = getopt(argc, argv, "a:A:cd:e:f:ghi:k:lL:p:P:sSt:T:v"))) {
switch (c) {
case 'a':
oneshot = atoi(optarg);
break;
case 'A':
periodic = atoi(optarg);
break;
case 'c':
capabilities = 1;
break;
case 'd':
device = optarg;
break;
case 'e':
extts = atoi(optarg);
break;
case 'f':
adjfreq = atoi(optarg);
break;
case 'g':
gettime = 1;
break;
case 'i':
index = atoi(optarg);
break;
case 'k':
pct_offset = 1;
n_samples = atoi(optarg);
break;
case 'l':
list_pins = 1;
break;
case 'L':
cnt = sscanf(optarg, "%d,%d", &pin_index, &pin_func);
if (cnt != 2) {
usage(progname);
return -1;
}
break;
case 'p':
perout = atoi(optarg);
break;
case 'P':
pps = atoi(optarg);
break;
case 's':
settime = 1;
break;
case 'S':
settime = 2;
break;
case 't':
adjtime = atoi(optarg);
break;
case 'T':
settime = 3;
seconds = atoi(optarg);
break;
case 'h':
usage(progname);
return 0;
case '?':
default:
usage(progname);
return -1;
}
}
fd = open(device, O_RDWR);
if (fd < 0) {
fprintf(stderr, "opening %s: %s\n", device, strerror(errno));
return -1;
}
clkid = get_clockid(fd);
if (CLOCK_INVALID == clkid) {
fprintf(stderr, "failed to read clock id\n");
return -1;
}
if (capabilities) {
if (ioctl(fd, PTP_CLOCK_GETCAPS, &caps)) {
perror("PTP_CLOCK_GETCAPS");
} else {
printf("capabilities:\n"
" %d maximum frequency adjustment (ppb)\n"
" %d programmable alarms\n"
" %d external time stamp channels\n"
" %d programmable periodic signals\n"
" %d pulse per second\n"
" %d programmable pins\n"
" %d cross timestamping\n",
caps.max_adj,
caps.n_alarm,
caps.n_ext_ts,
caps.n_per_out,
caps.pps,
caps.n_pins,
caps.cross_timestamping);
}
}
if (0x7fffffff != adjfreq) {
memset(&tx, 0, sizeof(tx));
tx.modes = ADJ_FREQUENCY;
tx.freq = ppb_to_scaled_ppm(adjfreq);
if (clock_adjtime(clkid, &tx)) {
perror("clock_adjtime");
} else {
puts("frequency adjustment okay");
}
}
if (adjtime) {
memset(&tx, 0, sizeof(tx));
tx.modes = ADJ_SETOFFSET;
tx.time.tv_sec = adjtime;
tx.time.tv_usec = 0;
if (clock_adjtime(clkid, &tx) < 0) {
perror("clock_adjtime");
} else {
puts("time shift okay");
}
}
if (gettime) {
if (clock_gettime(clkid, &ts)) {
perror("clock_gettime");
} else {
printf("clock time: %ld.%09ld or %s",
ts.tv_sec, ts.tv_nsec, ctime(&ts.tv_sec));
}
}
if (settime == 1) {
clock_gettime(CLOCK_REALTIME, &ts);
if (clock_settime(clkid, &ts)) {
perror("clock_settime");
} else {
puts("set time okay");
}
}
if (settime == 2) {
clock_gettime(clkid, &ts);
if (clock_settime(CLOCK_REALTIME, &ts)) {
perror("clock_settime");
} else {
puts("set time okay");
}
}
if (settime == 3) {
ts.tv_sec = seconds;
ts.tv_nsec = 0;
if (clock_settime(clkid, &ts)) {
perror("clock_settime");
} else {
puts("set time okay");
}
}
if (extts) {
memset(&extts_request, 0, sizeof(extts_request));
extts_request.index = index;
extts_request.flags = PTP_ENABLE_FEATURE;
if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
perror("PTP_EXTTS_REQUEST");
extts = 0;
} else {
puts("external time stamp request okay");
}
for (; extts; extts--) {
cnt = read(fd, &event, sizeof(event));
if (cnt != sizeof(event)) {
perror("read");
break;
}
printf("event index %u at %lld.%09u\n", event.index,
event.t.sec, event.t.nsec);
fflush(stdout);
}
/* Disable the feature again. */
extts_request.flags = 0;
if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
perror("PTP_EXTTS_REQUEST");
}
}
if (list_pins) {
int n_pins = 0;
if (ioctl(fd, PTP_CLOCK_GETCAPS, &caps)) {
perror("PTP_CLOCK_GETCAPS");
} else {
n_pins = caps.n_pins;
}
for (i = 0; i < n_pins; i++) {
desc.index = i;
if (ioctl(fd, PTP_PIN_GETFUNC, &desc)) {
perror("PTP_PIN_GETFUNC");
break;
}
printf("name %s index %u func %u chan %u\n",
desc.name, desc.index, desc.func, desc.chan);
}
}
if (oneshot) {
install_handler(SIGALRM, handle_alarm);
/* Create a timer. */
sigevent.sigev_notify = SIGEV_SIGNAL;
sigevent.sigev_signo = SIGALRM;
if (timer_create(clkid, &sigevent, &timerid)) {
perror("timer_create");
return -1;
}
/* Start the timer. */
memset(&timeout, 0, sizeof(timeout));
timeout.it_value.tv_sec = oneshot;
if (timer_settime(timerid, 0, &timeout, NULL)) {
perror("timer_settime");
return -1;
}
pause();
timer_delete(timerid);
}
if (periodic) {
install_handler(SIGALRM, handle_alarm);
/* Create a timer. */
sigevent.sigev_notify = SIGEV_SIGNAL;
sigevent.sigev_signo = SIGALRM;
if (timer_create(clkid, &sigevent, &timerid)) {
perror("timer_create");
return -1;
}
/* Start the timer. */
memset(&timeout, 0, sizeof(timeout));
timeout.it_interval.tv_sec = periodic;
timeout.it_value.tv_sec = periodic;
if (timer_settime(timerid, 0, &timeout, NULL)) {
perror("timer_settime");
return -1;
}
while (1) {
pause();
}
timer_delete(timerid);
}
if (perout >= 0) {
if (clock_gettime(clkid, &ts)) {
perror("clock_gettime");
return -1;
}
memset(&perout_request, 0, sizeof(perout_request));
perout_request.index = index;
perout_request.start.sec = ts.tv_sec + 2;
perout_request.start.nsec = 0;
perout_request.period.sec = 0;
perout_request.period.nsec = perout;
if (ioctl(fd, PTP_PEROUT_REQUEST, &perout_request)) {
perror("PTP_PEROUT_REQUEST");
} else {
puts("periodic output request okay");
}
}
if (pin_index >= 0) {
memset(&desc, 0, sizeof(desc));
desc.index = pin_index;
desc.func = pin_func;
desc.chan = index;
if (ioctl(fd, PTP_PIN_SETFUNC, &desc)) {
perror("PTP_PIN_SETFUNC");
} else {
puts("set pin function okay");
}
}
if (pps != -1) {
int enable = pps ? 1 : 0;
if (ioctl(fd, PTP_ENABLE_PPS, enable)) {
perror("PTP_ENABLE_PPS");
} else {
puts("pps for system time request okay");
}
}
if (pct_offset) {
if (n_samples <= 0 || n_samples > 25) {
puts("n_samples should be between 1 and 25");
usage(progname);
return -1;
}
sysoff = calloc(1, sizeof(*sysoff));
if (!sysoff) {
perror("calloc");
return -1;
}
sysoff->n_samples = n_samples;
if (ioctl(fd, PTP_SYS_OFFSET, sysoff))
perror("PTP_SYS_OFFSET");
else
puts("system and phc clock time offset request okay");
pct = &sysoff->ts[0];
for (i = 0; i < sysoff->n_samples; i++) {
t1 = pctns(pct+2*i);
tp = pctns(pct+2*i+1);
t2 = pctns(pct+2*i+2);
interval = t2 - t1;
offset = (t2 + t1) / 2 - tp;
printf("system time: %lld.%u\n",
(pct+2*i)->sec, (pct+2*i)->nsec);
printf("phc time: %lld.%u\n",
(pct+2*i+1)->sec, (pct+2*i+1)->nsec);
printf("system time: %lld.%u\n",
(pct+2*i+2)->sec, (pct+2*i+2)->nsec);
printf("system/phc clock time offset is %" PRId64 " ns\n"
"system clock time delay is %" PRId64 " ns\n",
offset, interval);
}
free(sysoff);
}
close(fd);
return 0;
}
/* wake up when the system time changes underneath us */
static int manager_clock_watch_setup(Manager *m) {
struct itimerspec its = {
.it_value.tv_sec = TIME_T_MAX
};
int r;
assert(m);
m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
safe_close(m->clock_watch_fd);
m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
if (m->clock_watch_fd < 0) {
log_error("Failed to create timerfd: %m");
return -errno;
}
if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) {
log_error("Failed to set up timerfd: %m");
return -errno;
}
r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
if (r < 0) {
log_error("Failed to create clock watch event source: %s", strerror(-r));
return r;
}
return 0;
}
static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
struct timex tmx = {};
int r;
assert(m);
/*
* For small deltas, tell the kernel to gradually adjust the system
* clock to the NTP time, larger deltas are just directly set.
*/
if (fabs(offset) < NTP_MAX_ADJUST) {
tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
tmx.status = STA_PLL;
tmx.offset = offset * NSEC_PER_SEC;
tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4;
tmx.maxerror = 0;
tmx.esterror = 0;
log_debug(" adjust (slew): %+.3f sec\n", offset);
} else {
tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET;
/* ADJ_NANO uses nanoseconds in the microseconds field */
tmx.time.tv_sec = (long)offset;
tmx.time.tv_usec = (offset - tmx.time.tv_sec) * NSEC_PER_SEC;
/* the kernel expects -0.3s as {-1, 7000.000.000} */
if (tmx.time.tv_usec < 0) {
tmx.time.tv_sec -= 1;
tmx.time.tv_usec += NSEC_PER_SEC;
}
m->jumped = true;
log_debug(" adjust (jump): %+.3f sec\n", offset);
}
/*
* An unset STA_UNSYNC will enable the kernel's 11-minute mode,
* which syncs the system time periodically to the RTC.
*
* In case the RTC runs in local time, never touch the RTC,
* we have no way to properly handle daylight saving changes and
* mobile devices moving between time zones.
*/
if (m->rtc_local_time)
tmx.status |= STA_UNSYNC;
switch (leap_sec) {
case 1:
tmx.status |= STA_INS;
break;
case -1:
tmx.status |= STA_DEL;
break;
}
r = clock_adjtime(CLOCK_REALTIME, &tmx);
if (r < 0)
return r;
touch("/var/lib/systemd/clock");
m->drift_ppm = tmx.freq / 65536;
log_debug(" status : %04i %s\n"
" time now : %li.%03llu\n"
" constant : %li\n"
" offset : %+.3f sec\n"
" freq offset : %+li (%i ppm)\n",
tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
tmx.time.tv_sec, (unsigned long long) (tmx.time.tv_usec / NSEC_PER_MSEC),
tmx.constant,
(double)tmx.offset / NSEC_PER_SEC,
tmx.freq, m->drift_ppm);
return 0;
}
static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
unsigned int i, idx_cur, idx_new, idx_min;
double jitter;
double j;
assert(m);
m->packet_count++;
/* ignore initial sample */
if (m->packet_count == 1)
return false;
/* store the current data in our samples array */
idx_cur = m->samples_idx;
idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
m->samples_idx = idx_new;
m->samples[idx_new].offset = offset;
m->samples[idx_new].delay = delay;
/* calculate new jitter value from the RMS differences relative to the lowest delay sample */
jitter = m->samples_jitter;
for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
idx_min = i;
j = 0;
for (i = 0; i < ELEMENTSOF(m->samples); i++)
j += square(m->samples[i].offset - m->samples[idx_min].offset);
m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
/* ignore samples when resyncing */
if (m->poll_resync)
return false;
/* always accept offset if we are farther off than the round-trip delay */
if (fabs(offset) > delay)
return false;
/* we need a few samples before looking at them */
if (m->packet_count < 4)
return false;
/* do not accept anything worse than the maximum possible error of the best sample */
if (fabs(offset) > m->samples[idx_min].delay)
return true;
/* compare the difference between the current offset to the previous offset and jitter */
return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
}