faraphel/chrony
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

clientlog: measure request rates

Browse source 
Extend the record with estimates of the current client's NTP and command
request rates. Store them as 8-bit scaled log2 values to save memory.
This commit is contained in:
Miroslav Lichvar 2015-11-25 09:57:12 +01:00
parent 464cdbbb6e
commit 830135edea
1 changed files with 58 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

62
clientlog.c
View file

@ -47,6 +47,8 @@ typedef struct {
IPAddr ip_addr;
uint32_t ntp_hits;
uint32_t cmd_hits;
int8_t ntp_rate;
int8_t cmd_rate;
time_t last_ntp_hit;
time_t last_cmd_hit;
} Record;
@ -71,6 +73,11 @@ static unsigned int slots;
/* Maximum number of slots given memory allocation limit */
static unsigned int max_slots;
/* Request rates are saved in the record as 8-bit scaled log2 values */
#define RATE_SCALE 4
#define MIN_RATE (-14 * RATE_SCALE)
#define INVALID_RATE -128
/* Flag indicating whether facility is turned on or not */
static int active;
@ -130,6 +137,7 @@ get_record(IPAddr *ip)
record->ip_addr = *ip;
record->ntp_hits = record->cmd_hits = 0;
record->ntp_rate = record->cmd_rate = INVALID_RATE;
record->last_ntp_hit = record->last_cmd_hit = 0;
return record;
@ -184,6 +192,47 @@ expand_hashtable(void)
/* ================================================== */
static int
update_rate(int rate, time_t now, time_t last_hit)
{
uint32_t interval;
int interval2;
if (!last_hit || now < last_hit)
return rate;
interval = now - last_hit;
/* Convert the interval to scaled and rounded log2 */
if (interval) {
interval += interval >> 1;
for (interval2 = 0; interval2 < -MIN_RATE; interval2 += RATE_SCALE) {
if (interval <= 1)
break;
interval >>= 1;
}
} else {
interval2 = -RATE_SCALE;
}
if (rate == INVALID_RATE)
return -interval2;
/* Update the rate in a rough approximation of exponential moving average */
if (rate < -interval2) {
rate++;
} else if (rate > -interval2) {
if (rate > RATE_SCALE * 5 / 2 - interval2)
rate = RATE_SCALE * 5 / 2 - interval2;
else
rate = (rate - interval2 - 1) / 2;
}
return rate;
}
/* ================================================== */
void
CLG_Initialise(void)
{
@ -195,10 +244,7 @@ CLG_Initialise(void)
configured memory limit. Take into account expanding of the hash
table where two copies exist at the same time. */
max_slots = CNF_GetClientLogLimit() / (sizeof (Record) * SLOT_SIZE * 3 / 2);
if (max_slots < MIN_SLOTS)
max_slots = MIN_SLOTS;
else if (max_slots > MAX_SLOTS)
max_slots = MAX_SLOTS;
max_slots = CLAMP(MIN_SLOTS, max_slots, MAX_SLOTS);
slots = 0;
records = NULL;
@ -232,7 +278,11 @@ CLG_LogNTPAccess(IPAddr *client, time_t now)
return;
record->ntp_hits++;
record->ntp_rate = update_rate(record->ntp_rate, now, record->last_ntp_hit);
record->last_ntp_hit = now;
DEBUG_LOG(LOGF_ClientLog, "NTP hits %"PRIu32" rate %d",
record->ntp_hits, record->ntp_rate);
}
/* ================================================== */
@ -250,7 +300,11 @@ CLG_LogCommandAccess(IPAddr *client, time_t now)
return;
record->cmd_hits++;
record->cmd_rate = update_rate(record->cmd_rate, now, record->last_cmd_hit);
record->last_cmd_hit = now;
DEBUG_LOG(LOGF_ClientLog, "Cmd hits %"PRIu32" rate %d",
record->cmd_hits, record->cmd_rate);
}
/* ================================================== */