Make receive_packet() more readable
This commit is contained in:
Miroslav Lichvar
parent
5079f6bbff
commit
030e3b2dab
1 changed files with 95 additions and 102 deletions
197
ntp_core.c
197
ntp_core.c
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@ -389,6 +389,39 @@ adjust_poll(NCR_Instance inst, double adj)
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/* ================================================== */
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/* ================================================== */
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static double
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get_poll_adj(NCR_Instance inst, double error_in_estimate, double peer_distance)
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{
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double poll_adj;
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if (error_in_estimate > peer_distance) {
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int shift = 0;
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unsigned long temp = (int)(error_in_estimate / peer_distance);
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do {
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shift++;
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temp>>=1;
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} while (temp);
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poll_adj = -shift - inst->poll_score + 0.5;
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} else {
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int samples = SRC_Samples(inst->source);
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/* Adjust polling interval so that the number of sourcestats samples
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remains close to the target value */
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poll_adj = ((double)samples / inst->poll_target - 1.0) / inst->poll_target;
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/* Make interval shortening quicker */
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if (samples < inst->poll_target) {
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poll_adj *= 2.0;
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}
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}
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return poll_adj;
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}
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/* ================================================== */
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static void
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static void
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transmit_packet(NTP_Mode my_mode, /* The mode this machine wants to be */
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transmit_packet(NTP_Mode my_mode, /* The mode this machine wants to be */
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int my_poll, /* The log2 of the local poll interval */
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int my_poll, /* The log2 of the local poll interval */
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@ -716,7 +749,6 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
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int poll_to_use;
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int poll_to_use;
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double delay_time = 0;
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double delay_time = 0;
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int requeue_transmit = 0;
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int requeue_transmit = 0;
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double poll_adj;
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/* ==================== */
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/* ==================== */
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@ -935,7 +967,7 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
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}
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}
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/* Check for Kiss-of-Death */
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/* Check for Kiss-of-Death */
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if (message->stratum > NTP_MAX_STRATUM && !source_is_synchronized) {
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if (!test7i && !source_is_synchronized) {
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if (!memcmp(&message->reference_id, "RATE", 4))
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if (!memcmp(&message->reference_id, "RATE", 4))
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kod_rate = 1;
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kod_rate = 1;
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}
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}
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@ -982,6 +1014,26 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
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LOG(LOGS_INFO, LOGF_NtpCore, "kod_rate=%d valid_kod=%d", kod_rate, valid_kod);
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LOG(LOGS_INFO, LOGF_NtpCore, "kod_rate=%d valid_kod=%d", kod_rate, valid_kod);
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#endif
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#endif
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/* Reduce polling rate if KoD RATE was received */
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if (kod_rate && valid_kod) {
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if (inst->remote_poll > inst->minpoll) {
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inst->minpoll = inst->remote_poll;
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if (inst->minpoll > inst->maxpoll)
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inst->maxpoll = inst->minpoll;
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if (inst->minpoll > inst->local_poll)
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inst->local_poll = inst->minpoll;
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LOG(LOGS_WARN, LOGF_NtpCore, "Received KoD RATE from %s, minpoll set to %d",
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UTI_IPToString(&inst->remote_addr.ip_addr), inst->minpoll);
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}
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/* Stop ongoing burst */
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if (inst->opmode == MD_BURST_WAS_OFFLINE || inst->opmode == MD_BURST_WAS_ONLINE) {
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inst->burst_good_samples_to_go = 0;
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LOG(LOGS_WARN, LOGF_NtpCore, "Received KoD RATE from %s, burst sampling stopped",
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UTI_IPToString(&inst->remote_addr.ip_addr), inst->minpoll);
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}
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}
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if (valid_header && valid_data) {
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if (valid_header && valid_data) {
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inst->tx_count = 0;
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inst->tx_count = 0;
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SRC_UpdateReachability(inst->source, 1);
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SRC_UpdateReachability(inst->source, 1);
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@ -996,103 +1048,52 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
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} else {
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} else {
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SRC_UnsetSelectable(inst->source);
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SRC_UnsetSelectable(inst->source);
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}
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}
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}
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/* Do this before we accumulate a new sample into the stats registers, obviously */
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if (good_data) {
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estimated_offset = SRC_PredictOffset(inst->source, &sample_time);
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/* Do this before we accumulate a new sample into the stats registers, obviously */
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estimated_offset = SRC_PredictOffset(inst->source, &sample_time);
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if (valid_header && good_data) {
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SRC_AccumulateSample(inst->source,
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SRC_AccumulateSample(inst->source,
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&sample_time,
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&sample_time,
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theta, delta, epsilon,
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theta, delta, epsilon,
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root_delay, root_dispersion,
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root_delay, root_dispersion,
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message->stratum, (NTP_Leap) pkt_leap);
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message->stratum, (NTP_Leap) pkt_leap);
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/* Now examine the registers. First though, if the prediction is
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/* Now examine the registers. First though, if the prediction is
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not even within +/- the peer distance of the peer, we are clearly
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not even within +/- the peer distance of the peer, we are clearly
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not tracking the peer at all well, so we back off the sampling
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not tracking the peer at all well, so we back off the sampling
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rate depending on just how bad the situation is. */
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rate depending on just how bad the situation is. */
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error_in_estimate = fabs(-theta - estimated_offset);
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error_in_estimate = fabs(-theta - estimated_offset);
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/* Now update the polling interval */
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if (error_in_estimate > peer_distance) {
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/* Now update the polling interval */
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int shift = 0;
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adjust_poll(inst, get_poll_adj(inst, error_in_estimate, peer_distance));
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unsigned long temp = (int)(error_in_estimate / peer_distance);
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do {
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/* If we're in burst mode, check whether the burst is completed and
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shift++;
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revert to the previous mode */
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temp>>=1;
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switch (inst->opmode) {
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} while (temp);
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case MD_BURST_WAS_ONLINE:
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case MD_BURST_WAS_OFFLINE:
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poll_adj = -shift - inst->poll_score + 0.5;
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--inst->burst_good_samples_to_go;
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if (inst->burst_good_samples_to_go <= 0) {
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if (inst->opmode == MD_BURST_WAS_ONLINE) {
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inst->opmode = MD_ONLINE;
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} else {
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inst->opmode = MD_OFFLINE;
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if (inst->timer_running) {
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SCH_RemoveTimeout(inst->timeout_id);
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inst->timer_running = 0;
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}
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}
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}
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break;
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default:
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break;
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}
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} else {
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} else {
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int samples = SRC_Samples(inst->source);
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/* Slowly increase the polling interval if we can't get good_data */
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adjust_poll(inst, 0.1);
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/* Adjust polling interval so that the number of sourcestats samples
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remains close to the target value */
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poll_adj = ((double)samples / inst->poll_target - 1.0) / inst->poll_target;
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/* Use higher gain when decreasing the interval */
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if (samples < inst->poll_target) {
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poll_adj *= 2.0;
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}
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}
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}
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adjust_poll(inst, poll_adj);
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} else if (valid_header && valid_data) {
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/* Slowly increase the polling interval if we can't get good_data */
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adjust_poll(inst, 0.1);
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}
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/* Reduce polling rate if KoD RATE was received */
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if (kod_rate && valid_kod) {
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if (inst->remote_poll > inst->minpoll) {
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inst->minpoll = inst->remote_poll;
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if (inst->minpoll > inst->maxpoll)
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inst->maxpoll = inst->minpoll;
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if (inst->minpoll > inst->local_poll)
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inst->local_poll = inst->minpoll;
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LOG(LOGS_WARN, LOGF_NtpCore, "Received KoD RATE from %s, minpoll set to %d", UTI_IPToString(&inst->remote_addr.ip_addr), inst->minpoll);
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}
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/* Stop ongoing burst */
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if (inst->opmode == MD_BURST_WAS_OFFLINE || inst->opmode == MD_BURST_WAS_ONLINE) {
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inst->burst_good_samples_to_go = 0;
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LOG(LOGS_WARN, LOGF_NtpCore, "Received KoD RATE from %s, burst sampling stopped", UTI_IPToString(&inst->remote_addr.ip_addr), inst->minpoll);
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}
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}
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/* If we're in burst mode, check whether the burst is completed and
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revert to the previous mode */
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switch (inst->opmode) {
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case MD_BURST_WAS_ONLINE:
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if (valid_header && good_data) {
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--inst->burst_good_samples_to_go;
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}
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if (inst->burst_good_samples_to_go <= 0) {
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inst->opmode = MD_ONLINE;
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}
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break;
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case MD_BURST_WAS_OFFLINE:
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if (valid_header && good_data) {
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--inst->burst_good_samples_to_go;
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}
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if (inst->burst_good_samples_to_go <= 0) {
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inst->opmode = MD_OFFLINE;
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if (inst->timer_running) {
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SCH_RemoveTimeout(inst->timeout_id);
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}
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inst->timer_running = 0;
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}
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break;
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default:
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break;
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}
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}
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/* And now, requeue the timer.
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/* And now, requeue the timer.
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@ -1151,12 +1152,10 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
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assert(0);
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assert(0);
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break;
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break;
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}
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}
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break;
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break;
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case MD_BURST_WAS_ONLINE:
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case MD_BURST_WAS_ONLINE:
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case MD_BURST_WAS_OFFLINE:
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case MD_BURST_WAS_OFFLINE:
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requeue_transmit = 1;
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requeue_transmit = 1;
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delay_time = BURST_INTERVAL;
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delay_time = BURST_INTERVAL;
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break;
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break;
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@ -1164,7 +1163,6 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
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default:
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default:
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assert(0);
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assert(0);
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break;
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break;
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}
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}
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if (kod_rate && valid_kod) {
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if (kod_rate && valid_kod) {
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@ -1174,6 +1172,7 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
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if (requeue_transmit) {
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if (requeue_transmit) {
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/* Get rid of old timeout and start a new one */
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/* Get rid of old timeout and start a new one */
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assert(inst->timer_running);
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SCH_RemoveTimeout(inst->timeout_id);
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SCH_RemoveTimeout(inst->timeout_id);
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inst->timeout_id = SCH_AddTimeoutInClass(delay_time, SAMPLING_SEPARATION,
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inst->timeout_id = SCH_AddTimeoutInClass(delay_time, SAMPLING_SEPARATION,
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SAMPLING_RANDOMNESS,
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SAMPLING_RANDOMNESS,
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@ -1196,12 +1195,6 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
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theta, delta, epsilon,
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theta, delta, epsilon,
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pkt_root_delay, pkt_root_dispersion);
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pkt_root_delay, pkt_root_dispersion);
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}
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}
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/* At this point we will have to do something about trimming the
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poll interval for the source and requeueing the polling timeout.
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Left until the source statistics management has been written */
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}
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}
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/* ================================================== */
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/* ================================================== */
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