#define RETRY_INTERVAL 5 /* on error, retry in N secs */
-#define QUERYTIME_MAX 15 /* wait for reply up to N secs */
+#define RESPONSE_INTERVAL 15 /* wait for reply up to N secs */
#define FREQ_TOLERANCE 0.000015 /* % frequency tolerance (15 PPM) */
+#define BURSTPOLL 0
#define MINPOLL 4 /* % minimum poll interval (6: 64 s) */
#define MAXPOLL 12 /* % maximum poll interval (12: 1.1h, 17: 36.4h) (was 17) */
#define MINDISP 0.01 /* % minimum dispersion (s) */
char *p_dotted;
/* when to send new query (if p_fd == -1)
* or when receive times out (if p_fd >= 0): */
- time_t next_action_time;
int p_fd;
int datapoint_idx;
uint32_t lastpkt_refid;
- uint8_t lastpkt_leap;
+ uint8_t lastpkt_status;
uint8_t lastpkt_stratum;
- uint8_t p_reachable_bits;
+ uint8_t reachable_bits;
+ double next_action_time;
double p_xmttime;
double lastpkt_recv_time;
double lastpkt_delay;
OPT_x = (1 << 3),
/* Insert new options above this line. */
/* Non-compat options: */
- OPT_p = (1 << 4),
- OPT_l = (1 << 5) * ENABLE_FEATURE_NTPD_SERVER,
+ OPT_w = (1 << 4),
+ OPT_p = (1 << 5),
+ OPT_l = (1 << 6) * ENABLE_FEATURE_NTPD_SERVER,
};
struct globals {
+ double cur_time;
/* total round trip delay to currently selected reference clock */
double rootdelay;
/* reference timestamp: time when the system clock was last set or corrected */
* in stratum 2+ packets, it's IPv4 address or 4 first bytes of MD5 hash of IPv6
*/
uint32_t refid;
- uint8_t leap;
+ uint8_t ntp_status;
/* precision is defined as the larger of the resolution and time to
* read the clock, in log2 units. For instance, the precision of a
* mains-frequency clock incrementing at 60 Hz is 16 ms, even when the
#define G_precision_sec (1.0 / (1 << (- G_precision_exp)))
uint8_t stratum;
/* Bool. After set to 1, never goes back to 0: */
-//TODO: fix logic:
-// uint8_t time_was_stepped;
- uint8_t adjtimex_was_done;
+ smallint adjtimex_was_done;
+ smallint initial_poll_complete;
uint8_t discipline_state; // doc calls it c.state
uint8_t poll_exp; // s.poll
return a;
return b;
}
-#define SQRT(x) (sqrt(x))
+static NOINLINE double my_SQRT(double X)
+{
+ union {
+ float f;
+ int32_t i;
+ } v;
+ double invsqrt;
+ double Xhalf = X * 0.5;
+
+ /* Fast and good approximation to 1/sqrt(X), black magic */
+ v.f = X;
+ /*v.i = 0x5f3759df - (v.i >> 1);*/
+ v.i = 0x5f375a86 - (v.i >> 1); /* - this constant is slightly better */
+ invsqrt = v.f; /* better than 0.2% accuracy */
+
+ /* Refining it using Newton's method: x1 = x0 - f(x0)/f'(x0)
+ * f(x) = 1/(x*x) - X (f==0 when x = 1/sqrt(X))
+ * f'(x) = -2/(x*x*x)
+ * f(x)/f'(x) = (X - 1/(x*x)) / (2/(x*x*x)) = X*x*x*x/2 - x/2
+ * x1 = x0 - (X*x0*x0*x0/2 - x0/2) = 1.5*x0 - X*x0*x0*x0/2 = x0*(1.5 - (X/2)*x0*x0)
+ */
+ invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); /* ~0.05% accuracy */
+ /* invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); 2nd iter: ~0.0001% accuracy */
+ /* With 4 iterations, more than half results will be exact,
+ * at 6th iterations result stabilizes with about 72% results exact.
+ * We are well satisfied with 0.05% accuracy.
+ */
+
+ return X * invsqrt; /* X * 1/sqrt(X) ~= sqrt(X) */
+}
+static ALWAYS_INLINE double SQRT(double X)
+{
+ /* If this arch doesn't use IEEE 754 floats, fall back to using libm */
+ if (sizeof(float) != 4)
+ return sqrt(X);
+
+ /* This avoids needing libm, saves about 0.5k on x86-32 */
+ return my_SQRT(X);
+}
static double
gettime1900d(void)
{
struct timeval tv;
gettimeofday(&tv, NULL); /* never fails */
- return (tv.tv_sec + 1.0e-6 * tv.tv_usec + OFFSET_1900_1970);
+ G.cur_time = tv.tv_sec + (1.0e-6 * tv.tv_usec) + OFFSET_1900_1970;
+ return G.cur_time;
}
static void
#endif
static double
-dispersion(const datapoint_t *dp, double t)
+dispersion(const datapoint_t *dp)
{
- return dp->d_dispersion + FREQ_TOLERANCE * (t - dp->d_recv_time);
+ return dp->d_dispersion + FREQ_TOLERANCE * (G.cur_time - dp->d_recv_time);
}
static double
-root_distance(peer_t *p, double t)
+root_distance(peer_t *p)
{
/* The root synchronization distance is the maximum error due to
* all causes of the local clock relative to the primary server.
return MAXD(MINDISP, p->lastpkt_rootdelay + p->lastpkt_delay) / 2
+ p->lastpkt_rootdisp
+ p->filter_dispersion
- + FREQ_TOLERANCE * (t - p->lastpkt_recv_time)
+ + FREQ_TOLERANCE * (G.cur_time - p->lastpkt_recv_time)
+ p->filter_jitter;
}
static void
set_next(peer_t *p, unsigned t)
{
- p->next_action_time = time(NULL) + t;
+ p->next_action_time = G.cur_time + t;
}
/*
* Peer clock filter and its helpers
*/
static void
-filter_datapoints(peer_t *p, double t)
+filter_datapoints(peer_t *p)
{
int i, idx;
+ int got_newest;
double minoff, maxoff, wavg, sum, w;
- double x = x;
+ double x = x; /* for compiler */
+ double oldest_off = oldest_off;
+ double oldest_age = oldest_age;
+ double newest_off = newest_off;
+ double newest_age = newest_age;
minoff = maxoff = p->filter_datapoint[0].d_offset;
for (i = 1; i < NUM_DATAPOINTS; i++) {
*/
wavg = 0;
w = 0.5;
- // n-1
- // --- dispersion(i)
- // filter_dispersion = \ -------------
- // / (i+1)
- // --- 2
- // i=0
+ /* n-1
+ * --- dispersion(i)
+ * filter_dispersion = \ -------------
+ * / (i+1)
+ * --- 2
+ * i=0
+ */
+ got_newest = 0;
sum = 0;
for (i = 0; i < NUM_DATAPOINTS; i++) {
VERB4 {
bb_error_msg("datapoint[%d]: off:%f disp:%f(%f) age:%f%s",
i,
p->filter_datapoint[idx].d_offset,
- p->filter_datapoint[idx].d_dispersion, dispersion(&p->filter_datapoint[idx], t),
- t - p->filter_datapoint[idx].d_recv_time,
+ p->filter_datapoint[idx].d_dispersion, dispersion(&p->filter_datapoint[idx]),
+ G.cur_time - p->filter_datapoint[idx].d_recv_time,
(minoff == p->filter_datapoint[idx].d_offset || maxoff == p->filter_datapoint[idx].d_offset)
? " (outlier by offset)" : ""
);
}
- sum += dispersion(&p->filter_datapoint[idx], t) / (2 << i);
+ sum += dispersion(&p->filter_datapoint[idx]) / (2 << i);
if (minoff == p->filter_datapoint[idx].d_offset) {
minoff -= 1; /* so that we don't match it ever again */
if (maxoff == p->filter_datapoint[idx].d_offset) {
maxoff += 1;
} else {
- x = p->filter_datapoint[idx].d_offset * w;
+ oldest_off = p->filter_datapoint[idx].d_offset;
+ oldest_age = G.cur_time - p->filter_datapoint[idx].d_recv_time;
+ if (!got_newest) {
+ got_newest = 1;
+ newest_off = oldest_off;
+ newest_age = oldest_age;
+ }
+ x = oldest_off * w;
wavg += x;
w /= 2;
}
idx = (idx - 1) & (NUM_DATAPOINTS - 1);
}
+ p->filter_dispersion = sum;
wavg += x; /* add another older6/64 to form older6/32 */
+ /* Fix systematic underestimation with large poll intervals.
+ * Imagine that we still have a bit of uncorrected drift,
+ * and poll interval is big (say, 100 sec). Offsets form a progression:
+ * 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 - 0.7 is most recent.
+ * The algorithm above drops 0.0 and 0.7 as outliers,
+ * and then we have this estimation, ~25% off from 0.7:
+ * 0.1/32 + 0.2/32 + 0.3/16 + 0.4/8 + 0.5/4 + 0.6/2 = 0.503125
+ */
+ x = oldest_age - newest_age;
+ if (x != 0) {
+ x = newest_age / x; /* in above example, 100 / (600 - 100) */
+ if (x < 1) { /* paranoia check */
+ x = (newest_off - oldest_off) * x; /* 0.5 * 100/500 = 0.1 */
+ wavg += x;
+ }
+ }
p->filter_offset = wavg;
- p->filter_dispersion = sum;
-//TODO: fix systematic underestimation with large poll intervals.
-// Imagine that we still have a bit of uncorrected drift,
-// and poll interval is big. Offsets form a progression:
-// 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7, 0.7 is most recent.
-// The algorithm above drops 0.0 and 0.7 as outliers,
-// and then we have this estimation, ~25% off from 0.7:
-// 0.1/32 + 0.2/32 + 0.3/16 + 0.4/8 + 0.5/4 + 0.6/2 = 0.503125
-
- // +----- -----+ ^ 1/2
- // | n-1 |
- // | --- |
- // 1 | \ 2 |
- // filter_jitter = --- * | / (avg-offset_j) |
- // n | --- |
- // | j=0 |
- // +----- -----+
- // where n is the number of valid datapoints in the filter (n > 1);
- // if filter_jitter < precision then filter_jitter = precision
+
+ /* +----- -----+ ^ 1/2
+ * | n-1 |
+ * | --- |
+ * | 1 \ 2 |
+ * filter_jitter = | --- * / (avg-offset_j) |
+ * | n --- |
+ * | j=0 |
+ * +----- -----+
+ * where n is the number of valid datapoints in the filter (n > 1);
+ * if filter_jitter < precision then filter_jitter = precision
+ */
sum = 0;
for (i = 0; i < NUM_DATAPOINTS; i++) {
sum += SQUARE(wavg - p->filter_datapoint[i].d_offset);
}
- sum = SQRT(sum) / NUM_DATAPOINTS;
+ sum = SQRT(sum / NUM_DATAPOINTS);
p->filter_jitter = sum > G_precision_sec ? sum : G_precision_sec;
- VERB3 bb_error_msg("filter offset:%f disp:%f jitter:%f",
- p->filter_offset, p->filter_dispersion, p->filter_jitter);
+ VERB3 bb_error_msg("filter offset:%f(corr:%e) disp:%f jitter:%f",
+ p->filter_offset, x,
+ p->filter_dispersion,
+ p->filter_jitter);
}
static void
-reset_peer_stats(peer_t *p, double t, double offset)
+reset_peer_stats(peer_t *p, double offset)
{
int i;
for (i = 0; i < NUM_DATAPOINTS; i++) {
p->filter_datapoint[i].d_offset -= offset;
}
} else {
- p->filter_datapoint[i].d_recv_time = t;
+ p->filter_datapoint[i].d_recv_time = G.cur_time;
p->filter_datapoint[i].d_offset = 0;
p->filter_datapoint[i].d_dispersion = MAXDISP;
}
if (offset < 16 * STEP_THRESHOLD) {
p->lastpkt_recv_time -= offset;
} else {
- p->p_reachable_bits = 0;
- p->lastpkt_recv_time = t;
+ p->reachable_bits = 0;
+ p->lastpkt_recv_time = G.cur_time;
}
- filter_datapoints(p, t); /* recalc p->filter_xxx */
- p->next_action_time -= (time_t)offset;
+ filter_datapoints(p); /* recalc p->filter_xxx */
+ p->next_action_time -= offset;
VERB5 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
}
p->p_dotted = xmalloc_sockaddr2dotted_noport(&p->p_lsa->u.sa);
p->p_fd = -1;
p->p_xmt_msg.m_status = MODE_CLIENT | (NTP_VERSION << 3);
- p->next_action_time = time(NULL); /* = set_next(p, 0); */
- reset_peer_stats(p, gettime1900d(), 16 * STEP_THRESHOLD);
- /* Speed up initial sync: with small offsets from peers,
- * 3 samples will sync
- */
- p->filter_datapoint[6].d_dispersion = 0;
- p->filter_datapoint[7].d_dispersion = 0;
+ p->next_action_time = G.cur_time; /* = set_next(p, 0); */
+ reset_peer_stats(p, 16 * STEP_THRESHOLD);
llist_add_to(&G.ntp_peers, p);
G.peer_cnt++;
return 0;
}
-static int
+static void
send_query_to_peer(peer_t *p)
{
- // Why do we need to bind()?
- // See what happens when we don't bind:
- //
- // socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
- // setsockopt(3, SOL_IP, IP_TOS, [16], 4) = 0
- // gettimeofday({1259071266, 327885}, NULL) = 0
- // sendto(3, "xxx", 48, MSG_DONTWAIT, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr("10.34.32.125")}, 16) = 48
- // ^^^ we sent it from some source port picked by kernel.
- // time(NULL) = 1259071266
- // write(2, "ntpd: entering poll 15 secs\n", 28) = 28
- // poll([{fd=3, events=POLLIN}], 1, 15000) = 1 ([{fd=3, revents=POLLIN}])
- // recv(3, "yyy", 68, MSG_DONTWAIT) = 48
- // ^^^ this recv will receive packets to any local port!
- //
- // Uncomment this and use strace to see it in action:
-#define PROBE_LOCAL_ADDR // { len_and_sockaddr lsa; lsa.len = LSA_SIZEOF_SA; getsockname(p->query.fd, &lsa.u.sa, &lsa.len); }
+ /* Why do we need to bind()?
+ * See what happens when we don't bind:
+ *
+ * socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
+ * setsockopt(3, SOL_IP, IP_TOS, [16], 4) = 0
+ * gettimeofday({1259071266, 327885}, NULL) = 0
+ * sendto(3, "xxx", 48, MSG_DONTWAIT, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr("10.34.32.125")}, 16) = 48
+ * ^^^ we sent it from some source port picked by kernel.
+ * time(NULL) = 1259071266
+ * write(2, "ntpd: entering poll 15 secs\n", 28) = 28
+ * poll([{fd=3, events=POLLIN}], 1, 15000) = 1 ([{fd=3, revents=POLLIN}])
+ * recv(3, "yyy", 68, MSG_DONTWAIT) = 48
+ * ^^^ this recv will receive packets to any local port!
+ *
+ * Uncomment this and use strace to see it in action:
+ */
+#define PROBE_LOCAL_ADDR /* { len_and_sockaddr lsa; lsa.len = LSA_SIZEOF_SA; getsockname(p->query.fd, &lsa.u.sa, &lsa.len); } */
if (p->p_fd == -1) {
int fd, family;
close(p->p_fd);
p->p_fd = -1;
set_next(p, RETRY_INTERVAL);
- return -1;
+ return;
}
- p->p_reachable_bits <<= 1;
+ p->reachable_bits <<= 1;
VERB1 bb_error_msg("sent query to %s", p->p_dotted);
- set_next(p, QUERYTIME_MAX);
-
- return 0;
+ set_next(p, RESPONSE_INTERVAL);
}
-static void
+static NOINLINE void
step_time(double offset)
{
+ llist_t *item;
double dtime;
struct timeval tv;
char buf[80];
bb_error_msg("setting clock to %s (offset %fs)", buf, offset);
-// G.time_was_stepped = 1;
+ /* Correct various fields which contain time-relative values: */
+
+ /* p->lastpkt_recv_time, p->next_action_time and such: */
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
+ peer_t *pp = (peer_t *) item->data;
+ reset_peer_stats(pp, offset);
+ }
+ /* Globals: */
+ G.cur_time -= offset;
+ G.last_update_recv_time -= offset;
}
{
const survivor_t *a = aa;
const survivor_t *b = bb;
- if (a->metric < b->metric)
+ if (a->metric < b->metric) {
return -1;
+ }
return (a->metric > b->metric);
}
static int
fit(peer_t *p, double rd)
{
- if (p->p_reachable_bits == 0) {
+ if ((p->reachable_bits & (p->reachable_bits-1)) == 0) {
+ /* One or zero bits in reachable_bits */
VERB3 bb_error_msg("peer %s unfit for selection: unreachable", p->p_dotted);
return 0;
}
-//TODO: we never accept such packets anyway, right?
- if ((p->lastpkt_leap & LI_ALARM) == LI_ALARM
+#if 0 /* we filter out such packets earlier */
+ if ((p->lastpkt_status & LI_ALARM) == LI_ALARM
|| p->lastpkt_stratum >= MAXSTRAT
) {
VERB3 bb_error_msg("peer %s unfit for selection: bad status/stratum", p->p_dotted);
return 0;
}
- /* rd is root_distance(p, t) */
+#endif
+ /* rd is root_distance(p) */
if (rd > MAXDIST + FREQ_TOLERANCE * (1 << G.poll_exp)) {
VERB3 bb_error_msg("peer %s unfit for selection: root distance too high", p->p_dotted);
return 0;
return 1;
}
static peer_t*
-select_and_cluster(double t)
+select_and_cluster(void)
{
llist_t *item;
int i, j;
num_points = 0;
item = G.ntp_peers;
- while (item != NULL) {
+ if (G.initial_poll_complete) while (item != NULL) {
peer_t *p = (peer_t *) item->data;
- double rd = root_distance(p, t);
+ double rd = root_distance(p);
double offset = p->filter_offset;
if (!fit(p, rd)) {
num_candidates = num_points / 3;
if (num_candidates == 0) {
VERB3 bb_error_msg("no valid datapoints, no peer selected");
- return NULL; /* never happers? */
+ return NULL;
}
//TODO: sorting does not seem to be done in reference code
qsort(point, num_points, sizeof(point[0]), compare_point_edge);
p = point[i].p;
survivor[num_survivors].p = p;
//TODO: save root_distance in point_t and reuse here?
- survivor[num_survivors].metric = MAXDIST * p->lastpkt_stratum + root_distance(p, t);
+ survivor[num_survivors].metric = MAXDIST * p->lastpkt_stratum + root_distance(p);
VERB4 bb_error_msg("survivor[%d] metric:%f peer:%s",
num_survivors, survivor[num_survivors].metric, p->p_dotted);
num_survivors++;
double min_jitter = min_jitter;
if (num_survivors <= MIN_CLUSTERED) {
- bb_error_msg("num_survivors %d <= %d, not discarding more",
+ VERB3 bb_error_msg("num_survivors %d <= %d, not discarding more",
num_survivors, MIN_CLUSTERED);
break;
}
selection_jitter_sq = 0;
for (j = 0; j < num_survivors; j++) {
peer_t *q = survivor[j].p;
-//TODO: where is 1/(n-1) * ... multiplier?
selection_jitter_sq += SQUARE(p->filter_offset - q->filter_offset);
}
if (i == 0 || selection_jitter_sq > max_selection_jitter) {
VERB5 bb_error_msg("survivor %d selection_jitter^2:%f",
i, selection_jitter_sq);
}
- max_selection_jitter = SQRT(max_selection_jitter);
+ max_selection_jitter = SQRT(max_selection_jitter / num_survivors);
VERB4 bb_error_msg("max_selection_jitter (at %d):%f min_jitter:%f",
max_idx, max_selection_jitter, min_jitter);
VERB3 bb_error_msg("selected peer %s filter_offset:%f age:%f",
survivor[0].p->p_dotted,
survivor[0].p->filter_offset,
- t - survivor[0].p->lastpkt_recv_time
+ G.cur_time - survivor[0].p->lastpkt_recv_time
);
return survivor[0].p;
}
* 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 last_update_recv_time=%f",
+ VERB3 bb_error_msg("disc_state=%d last update offset=%f recv_time=%f",
disc_state, offset, recv_time);
G.discipline_state = disc_state;
G.last_update_offset = offset;
#define STATE_FREQ 3 /* initial frequency */
#define STATE_SYNC 4 /* clock synchronized (normal operation) */
/* Return: -1: decrease poll interval, 0: leave as is, 1: increase */
-static int
-update_local_clock(peer_t *p, double t)
+static NOINLINE int
+update_local_clock(peer_t *p)
{
int rc;
long old_tmx_offset;
double offset = p->filter_offset;
double recv_time = p->lastpkt_recv_time;
double abs_offset;
+#if !USING_KERNEL_PLL_LOOP
double freq_drift;
+#endif
double since_last_update;
double etemp, dtemp;
* and frequency errors.
*/
since_last_update = recv_time - G.reftime;
+#if !USING_KERNEL_PLL_LOOP
freq_drift = 0;
+#endif
if (G.discipline_state == STATE_FREQ) {
/* Ignore updates until the stepout threshold */
if (since_last_update < WATCH_THRESHOLD) {
WATCH_THRESHOLD - since_last_update);
return 0; /* "leave poll interval as is" */
}
+#if !USING_KERNEL_PLL_LOOP
freq_drift = (offset - G.last_update_offset) / since_last_update;
+#endif
}
/* There are two main regimes: when the
* offset exceeds the step threshold and when it does not.
*/
if (abs_offset > STEP_THRESHOLD) {
- llist_t *item;
-
switch (G.discipline_state) {
case STATE_SYNC:
/* The first outlyer: ignore it, switch to SPIK state */
G.polladj_count = 0;
G.poll_exp = MINPOLL;
G.stratum = MAXSTRAT;
- for (item = G.ntp_peers; item != NULL; item = item->link) {
- peer_t *pp = (peer_t *) item->data;
- reset_peer_stats(pp, t, offset);
- }
if (G.discipline_state == STATE_NSET) {
set_new_values(STATE_FREQ, /*offset:*/ 0, recv_time);
return 1; /* "ok to increase poll interval" */
} else { /* abs_offset <= STEP_THRESHOLD */
- if (G.poll_exp < MINPOLL) {
- VERB3 bb_error_msg("saw small offset %f, disabling burst mode", offset);
+ if (G.poll_exp < MINPOLL && G.initial_poll_complete) {
+ VERB3 bb_error_msg("small offset:%f, disabling burst mode", offset);
+ G.polladj_count = 0;
G.poll_exp = MINPOLL;
}
*/
set_new_values(STATE_FREQ, offset, recv_time);
VERB3 bb_error_msg("transitioning to FREQ, datapoint ignored");
- return -1; /* "decrease poll interval" */
+ return 0; /* "leave poll interval as is" */
#if 0 /* this is dead code for now */
case STATE_FSET:
break;
default:
+#if !USING_KERNEL_PLL_LOOP
/* Compute freq_drift due to PLL and FLL contributions.
*
* The FLL and PLL frequency gain constants
etemp = MIND(since_last_update, (1 << G.poll_exp));
dtemp = (4 * PLL) << G.poll_exp;
freq_drift += offset * etemp / SQUARE(dtemp);
+#endif
set_new_values(STATE_SYNC, offset, recv_time);
break;
}
G.stratum = p->lastpkt_stratum + 1;
}
- G.reftime = t;
- G.leap = p->lastpkt_leap;
+ G.reftime = G.cur_time;
+ G.ntp_status = p->lastpkt_status;
G.refid = p->lastpkt_refid;
G.rootdelay = p->lastpkt_rootdelay + p->lastpkt_delay;
dtemp = p->filter_jitter; // SQRT(SQUARE(p->filter_jitter) + SQUARE(s.jitter));
- dtemp += MAXD(p->filter_dispersion + FREQ_TOLERANCE * (t - p->lastpkt_recv_time) + abs_offset, MINDISP);
+ 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);
/* + (G.last_update_offset < 0 ? -0.5 : 0.5) - too small to bother */
+ old_tmx_offset; /* almost always 0 */
tmx.status = STA_PLL;
- //if (sys_leap == LEAP_ADDSECOND)
- // tmx.status |= STA_INS;
- //else if (sys_leap == LEAP_DELSECOND)
- // tmx.status |= STA_DEL;
+ 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);
- VERB3 bb_error_msg("b adjtimex freq:%ld offset:%ld constant:%ld status:0x%x",
- tmx.freq, tmx.offset, tmx.constant, tmx.status);
rc = adjtimex(&tmx);
if (rc < 0)
bb_perror_msg_and_die("adjtimex");
- if (G.kernel_freq_drift != tmx.freq / 65536) {
- G.kernel_freq_drift = tmx.freq / 65536;
- VERB2 bb_error_msg("kernel clock drift: %ld ppm", G.kernel_freq_drift);
- }
- VERB3 {
- bb_error_msg("adjtimex:%d freq:%ld offset:%ld constant:%ld status:0x%x",
+ /* 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
+ if (G.kernel_freq_drift != tmx.freq / 65536) {
+ G.kernel_freq_drift = tmx.freq / 65536;
+ VERB2 bb_error_msg("kernel clock drift: %ld ppm", G.kernel_freq_drift);
}
-// #define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */ - ?
-// it appeared after a while:
-//ntpd: p adjtimex freq:-14545653 offset:-5396 constant:10 status:0x41
-//ntpd: c adjtimex freq:-14547835 offset:-8307 constant:10 status:0x1
-//ntpd: p adjtimex freq:-14547835 offset:-6398 constant:10 status:0x41
-//ntpd: c adjtimex freq:-14550486 offset:-10158 constant:10 status:0x1
-//ntpd: p adjtimex freq:-14550486 offset:-6132 constant:10 status:0x41
-//ntpd: c adjtimex freq:-14636129 offset:-10158 constant:10 status:0x4001
-//ntpd: p adjtimex freq:-14636129 offset:-10002 constant:10 status:0x4041
-//ntpd: c adjtimex freq:-14636245 offset:-7497 constant:10 status:0x1
-//ntpd: p adjtimex freq:-14636245 offset:-4573 constant:10 status:0x41
-//ntpd: c adjtimex freq:-14642034 offset:-11715 constant:10 status:0x1
-//ntpd: p adjtimex freq:-14642034 offset:-4098 constant:10 status:0x41
-//ntpd: c adjtimex freq:-14699112 offset:-11746 constant:10 status:0x4001
-//ntpd: p adjtimex freq:-14699112 offset:-4239 constant:10 status:0x4041
-//ntpd: c adjtimex freq:-14762330 offset:-12786 constant:10 status:0x4001
-//ntpd: p adjtimex freq:-14762330 offset:-4434 constant:10 status:0x4041
-//ntpd: b adjtimex freq:0 offset:-9669 constant:8 status:0x1
-//ntpd: adjtimex:0 freq:-14809095 offset:-9669 constant:10 status:0x4001
-//ntpd: c adjtimex freq:-14809095 offset:-9669 constant:10 status:0x4001
return 1; /* "ok to increase poll interval" */
}
return interval;
}
static unsigned
-poll_interval(int exponent) /* exp is always -1 or 0 */
+poll_interval(int exponent)
{
- /* Want to send next packet at (1 << G.poll_exp) + small random value */
unsigned interval, r;
- exponent += G.poll_exp; /* G.poll_exp is always > 0 */
- /* never true: if (exp < 0) exp = 0; */
+ exponent = G.poll_exp + exponent;
+ if (exponent < 0)
+ exponent = 0;
interval = 1 << exponent;
r = random();
interval += ((r & (interval-1)) >> 4) + ((r >> 8) & 1); /* + 1/16 of interval, max */
VERB3 bb_error_msg("chose poll interval:%u (poll_exp:%d exp:%d)", interval, G.poll_exp, exponent);
return interval;
}
-static void
+static NOINLINE void
recv_and_process_peer_pkt(peer_t *p)
{
int rc;
|| errno == EAGAIN
) {
//TODO: always do this?
- set_next(p, retry_interval());
- goto close_sock;
+ interval = retry_interval();
+ goto set_next_and_close_sock;
}
xfunc_die();
}
// "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 close_sock;
+ goto set_next_and_close_sock;
}
-// /*
-// * Verify the server is synchronized with valid stratum and
-// * reference time not later than the transmit time.
-// */
-// if (p->lastpkt_leap == NOSYNC || p->lastpkt_stratum >= MAXSTRAT)
-// return; /* unsynchronized */
-//
// /* Verify valid root distance */
// if (msg.m_rootdelay / 2 + msg.m_rootdisp >= MAXDISP || p->lastpkt_reftime > msg.m_xmt)
// return; /* invalid header values */
- p->lastpkt_leap = msg.m_status;
+ p->lastpkt_status = msg.m_status;
+ p->lastpkt_stratum = msg.m_stratum;
p->lastpkt_rootdelay = sfp_to_d(msg.m_rootdelay);
p->lastpkt_rootdisp = sfp_to_d(msg.m_rootdisp);
p->lastpkt_refid = msg.m_refid;
T1 = p->p_xmttime;
T2 = lfp_to_d(msg.m_rectime);
T3 = lfp_to_d(msg.m_xmttime);
- T4 = gettime1900d();
+ T4 = G.cur_time;
p->lastpkt_recv_time = T4;
VERB5 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
- p->datapoint_idx = p->p_reachable_bits ? (p->datapoint_idx + 1) % NUM_DATAPOINTS : 0;
+ 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;
if (p->lastpkt_delay < G_precision_sec)
p->lastpkt_delay = G_precision_sec;
datapoint->d_dispersion = LOG2D(msg.m_precision_exp) + G_precision_sec;
- if (!p->p_reachable_bits) {
+ if (!p->reachable_bits) {
/* 1st datapoint ever - replicate offset in every element */
int i;
for (i = 1; i < NUM_DATAPOINTS; i++) {
}
}
- p->p_reachable_bits |= 1;
- VERB1 {
- bb_error_msg("reply from %s: reach 0x%02x offset %f delay %f",
+ p->reachable_bits |= 1;
+ if ((MAX_VERBOSE && G.verbose) || (option_mask32 & OPT_w)) {
+ bb_error_msg("reply from %s: reach 0x%02x offset %f delay %f status 0x%02x strat %d refid 0x%08x rootdelay %f",
p->p_dotted,
- p->p_reachable_bits,
- datapoint->d_offset, p->lastpkt_delay);
+ p->reachable_bits,
+ datapoint->d_offset,
+ p->lastpkt_delay,
+ p->lastpkt_status,
+ p->lastpkt_stratum,
+ p->lastpkt_refid,
+ p->lastpkt_rootdelay
+ /* not shown: m_ppoll, m_precision_exp, m_rootdisp,
+ * m_reftime, m_orgtime, m_rectime, m_xmttime
+ */
+ );
}
/* Muck with statictics and update the clock */
- filter_datapoints(p, T4);
- q = select_and_cluster(T4);
+ filter_datapoints(p);
+ q = select_and_cluster();
rc = -1;
- if (q)
- rc = update_local_clock(q, T4);
+ if (q) {
+ rc = 0;
+ if (!(option_mask32 & OPT_w))
+ rc = update_local_clock(q);
+ }
if (rc != 0) {
/* Adjust the poll interval by comparing the current offset
if (G.polladj_count < -POLLADJ_LIMIT) {
G.polladj_count = 0;
if (G.poll_exp > MINPOLL) {
+ llist_t *item;
+
G.poll_exp--;
+ /* Correct p->next_action_time in each peer
+ * which waits for sending, so that they send earlier.
+ * Old pp->next_action_time are on the order
+ * of t + (1 << old_poll_exp) + small_random,
+ * we simply need to subtract ~half of that.
+ */
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
+ peer_t *pp = (peer_t *) item->data;
+ if (pp->p_fd < 0)
+ pp->next_action_time -= (1 << G.poll_exp);
+ }
VERB3 bb_error_msg("polladj: discipline_jitter:%f --poll_exp=%d",
G.discipline_jitter, G.poll_exp);
}
/* Decide when to send new query for this peer */
interval = poll_interval(0);
- set_next(p, interval);
- close_sock:
+ set_next_and_close_sock:
+ set_next(p, interval);
/* We do not expect any more packets from this peer for now.
* Closing the socket informs kernel about it.
* We open a new socket when we send a new query.
}
#if ENABLE_FEATURE_NTPD_SERVER
-static void
+static NOINLINE void
recv_and_process_client_pkt(void /*int fd*/)
{
ssize_t size;
uint8_t version;
- double rectime;
len_and_sockaddr *to;
struct sockaddr *from;
msg_t msg;
/* Build a reply packet */
memset(&msg, 0, sizeof(msg));
- msg.m_status = G.stratum < MAXSTRAT ? G.leap : LI_ALARM;
+ msg.m_status = G.stratum < MAXSTRAT ? G.ntp_status : LI_ALARM;
msg.m_status |= (query_status & VERSION_MASK);
msg.m_status |= ((query_status & MODE_MASK) == MODE_CLIENT) ?
MODE_SERVER : MODE_SYM_PAS;
msg.m_stratum = G.stratum;
msg.m_ppoll = G.poll_exp;
msg.m_precision_exp = G_precision_exp;
- rectime = gettime1900d();
- msg.m_xmttime = msg.m_rectime = d_to_lfp(rectime);
+ /* this time was obtained between poll() and recv() */
+ msg.m_rectime = d_to_lfp(G.cur_time);
+ msg.m_xmttime = d_to_lfp(gettime1900d()); /* this instant */
msg.m_reftime = d_to_lfp(G.reftime);
msg.m_orgtime = query_xmttime;
msg.m_rootdelay = d_to_sfp(G.rootdelay);
bb_error_msg_and_die(bb_msg_you_must_be_root);
/* Set some globals */
-#if 0
- /* With constant b = 100, G.precision_exp is also constant -6.
- * Uncomment this to verify.
- */
- {
- int prec = 0;
- int b;
-# if 0
- struct timespec tp;
- /* We can use sys_clock_getres but assuming 10ms tick should be fine */
- clock_getres(CLOCK_REALTIME, &tp);
- tp.tv_sec = 0;
- tp.tv_nsec = 10000000;
- b = 1000000000 / tp.tv_nsec; /* convert to Hz */
-# else
- b = 100; /* b = 1000000000/10000000 = 100 */
-# endif
- while (b > 1)
- prec--, b >>= 1;
- /*G.precision_exp = prec;*/
- /*G.precision_sec = (1.0 / (1 << (- prec)));*/
- bb_error_msg("G.precision_exp:%d sec:%f", prec, G_precision_sec); /* -6 */
- }
-#endif
G.stratum = MAXSTRAT;
- G.poll_exp = 1; /* should use MINPOLL, but 1 speeds up initial sync */
- G.reftime = G.last_update_recv_time = gettime1900d();
+ if (BURSTPOLL != 0)
+ G.poll_exp = BURSTPOLL; /* speeds up initial sync */
+ G.reftime = G.last_update_recv_time = gettime1900d(); /* sets G.cur_time too */
/* Parse options */
peers = NULL;
- opt_complementary = "dd:p::"; /* d: counter, p: list */
+ opt_complementary = "dd:p::wn"; /* d: counter; p: list; -w implies -n */
opts = getopt32(argv,
"nqNx" /* compat */
- "p:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
+ "wp:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
"d" /* compat */
"46aAbgL", /* compat, ignored */
&peers, &G.verbose);
int ntpd_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ntpd_main(int argc UNUSED_PARAM, char **argv)
{
- struct globals g;
+#undef G
+ struct globals G;
struct pollfd *pfd;
peer_t **idx2peer;
+ unsigned cnt;
- memset(&g, 0, sizeof(g));
- SET_PTR_TO_GLOBALS(&g);
+ memset(&G, 0, sizeof(G));
+ SET_PTR_TO_GLOBALS(&G);
ntp_init(argv);
- {
- /* if ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
- unsigned cnt = g.peer_cnt + ENABLE_FEATURE_NTPD_SERVER;
- idx2peer = xzalloc(sizeof(idx2peer[0]) * cnt);
- pfd = xzalloc(sizeof(pfd[0]) * cnt);
- }
+ /* If ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
+ cnt = G.peer_cnt + ENABLE_FEATURE_NTPD_SERVER;
+ idx2peer = xzalloc(sizeof(idx2peer[0]) * cnt);
+ pfd = xzalloc(sizeof(pfd[0]) * cnt);
+
+ /* Countdown: we never sync before we sent 5 packets to each peer
+ * NB: if some peer is not responding, we may end up sending
+ * fewer packets to it and more to other peers.
+ * NB2: sync usually happens using 5-1=4 packets, since last reply
+ * does not come back instantaneously.
+ */
+ cnt = G.peer_cnt * 5;
while (!bb_got_signal) {
llist_t *item;
unsigned i, j;
- unsigned sent_cnt, trial_cnt;
int nfds, timeout;
- time_t cur_time, nextaction;
+ double nextaction;
/* Nothing between here and poll() blocks for any significant time */
- cur_time = time(NULL);
- nextaction = cur_time + 3600;
+ nextaction = G.cur_time + 3600;
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++;
}
#endif
/* Pass over peer list, send requests, time out on receives */
- sent_cnt = trial_cnt = 0;
- for (item = g.ntp_peers; item != NULL; item = item->link) {
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
peer_t *p = (peer_t *) item->data;
- /* Overflow-safe "if (p->next_action_time <= cur_time) ..." */
- if ((int)(cur_time - p->next_action_time) >= 0) {
+ if (p->next_action_time <= G.cur_time) {
if (p->p_fd == -1) {
/* Time to send new req */
- trial_cnt++;
- if (send_query_to_peer(p) == 0)
- sent_cnt++;
+ if (--cnt == 0) {
+ G.initial_poll_complete = 1;
+ }
+ send_query_to_peer(p);
} else {
/* Timed out waiting for reply */
close(p->p_fd);
p->p_fd = -1;
- timeout = poll_interval(-1); /* try a bit faster */
+ timeout = poll_interval(-2); /* -2: try a bit sooner */
bb_error_msg("timed out waiting for %s, reach 0x%02x, next query in %us",
- p->p_dotted, p->p_reachable_bits, timeout);
+ p->p_dotted, p->reachable_bits, timeout);
set_next(p, timeout);
}
}
}
}
-// if ((trial_cnt > 0 && sent_cnt == 0) || g.peer_cnt == 0) {
-// G.time_was_stepped = 1;
-// }
-
- timeout = nextaction - cur_time;
- if (timeout < 1)
- timeout = 1;
+ timeout = nextaction - G.cur_time;
+ if (timeout < 0)
+ timeout = 0;
+ timeout++; /* (nextaction - G.cur_time) rounds down, compensating */
/* Here we may block */
VERB2 bb_error_msg("poll %us, sockets:%u", timeout, i);
nfds = poll(pfd, i, timeout * 1000);
+ gettime1900d(); /* sets G.cur_time */
if (nfds <= 0)
continue;
/* Process any received packets */
j = 0;
#if ENABLE_FEATURE_NTPD_SERVER
- if (g.listen_fd != -1) {
+ if (G.listen_fd != -1) {
if (pfd[0].revents /* & (POLLIN|POLLERR)*/) {
nfds--;
- recv_and_process_client_pkt(/*g.listen_fd*/);
+ recv_and_process_client_pkt(/*G.listen_fd*/);
+ gettime1900d(); /* sets G.cur_time */
}
j = 1;
}
if (pfd[j].revents /* & (POLLIN|POLLERR)*/) {
nfds--;
recv_and_process_peer_pkt(idx2peer[j]);
+ gettime1900d(); /* sets G.cur_time */
}
}
} /* while (!bb_got_signal) */
projects / oweals / busybox.git / blobdiff