MAXFREQ
#define MAXFREQ_SCALED ((s64)MAXFREQ << NTP_SCALE_SHIFT)
if ((freq_norm.sec == 0) || (freq_norm.nsec > MAXFREQ * freq_norm.sec) ||
(freq_norm.nsec < -MAXFREQ * freq_norm.sec)) {
ntpdata->time_maxerror += MAXFREQ / NSEC_PER_USEC;