relay: Add DNS metrics

Emit on the MetricsPort all the DNS statistics we have that is the total
number of queries seen and errors per record type.

Related to #40367

Signed-off-by: David Goulet <dgoulet@torproject.org>
This commit is contained in:
David Goulet 2021-05-06 10:58:37 -04:00
parent 423910e01b
commit c6f41d6038
2 changed files with 104 additions and 0 deletions

View File

@ -21,7 +21,11 @@
#include "feature/relay/relay_metrics.h"
#include "feature/stats/rephist.h"
#include <event2/dns.h>
/** Declarations of each fill function for metrics defined in base_metrics. */
static void fill_dns_error_values(void);
static void fill_dns_query_values(void);
static void fill_global_bw_limit_values(void);
static void fill_socket_values(void);
static void fill_onionskins_values(void);
@ -61,6 +65,20 @@ static const relay_metrics_entry_t base_metrics[] =
.help = "Total number of global connection bucket limit reached",
.fill_fn = fill_global_bw_limit_values,
},
{
.key = RELAY_METRICS_NUM_DNS,
.type = METRICS_TYPE_COUNTER,
.name = METRICS_NAME(relay_exit_dns_query_total),
.help = "Total number of DNS queries done by this relay",
.fill_fn = fill_dns_query_values,
},
{
.key = RELAY_METRICS_NUM_DNS_ERRORS,
.type = METRICS_TYPE_COUNTER,
.name = METRICS_NAME(relay_exit_dns_error_total),
.help = "Total number of DNS errors encountered by this relay",
.fill_fn = fill_dns_error_values,
},
};
static const size_t num_base_metrics = ARRAY_LENGTH(base_metrics);
@ -85,6 +103,88 @@ handshake_type_to_str(const uint16_t type)
}
}
/** Helper array containing mapping for the name of the different DNS records
* and their corresponding libevent values. */
static struct dns_type {
const char *name;
uint8_t type;
} dns_types[] = {
{ .name = "A", .type = DNS_IPv4_A },
{ .name = "PTR", .type = DNS_PTR },
{ .name = "AAAA", .type = DNS_IPv6_AAAA },
};
static const size_t num_dns_types = ARRAY_LENGTH(dns_types);
/** Fill function for the RELAY_METRICS_NUM_DNS_ERRORS metrics. */
static void
fill_dns_error_values(void)
{
metrics_store_entry_t *sentry;
const relay_metrics_entry_t *rentry =
&base_metrics[RELAY_METRICS_NUM_DNS_ERRORS];
/* Helper array to map libeven DNS errors to their names and so we can
* iterate over this array to add all metrics. */
static struct dns_error {
const char *name;
uint8_t key;
} errors[] = {
{ .name = "success", .key = DNS_ERR_NONE },
{ .name = "format", .key = DNS_ERR_FORMAT },
{ .name = "serverfailed", .key = DNS_ERR_SERVERFAILED },
{ .name = "notexist", .key = DNS_ERR_NOTEXIST },
{ .name = "notimpl", .key = DNS_ERR_NOTIMPL },
{ .name = "refused", .key = DNS_ERR_REFUSED },
{ .name = "truncated", .key = DNS_ERR_TRUNCATED },
{ .name = "unknown", .key = DNS_ERR_UNKNOWN },
{ .name = "timeout", .key = DNS_ERR_TIMEOUT },
{ .name = "shutdown", .key = DNS_ERR_SHUTDOWN },
{ .name = "cancel", .key = DNS_ERR_CANCEL },
{ .name = "nodata", .key = DNS_ERR_NODATA },
};
static const size_t num_errors = ARRAY_LENGTH(errors);
for (size_t i = 0; i < num_dns_types; i++) {
/* Dup the label because metrics_format_label() returns a pointer to a
* string on the stack and we need that label for all metrics. */
char *record_label =
tor_strdup(metrics_format_label("record", dns_types[i].name));
for (size_t j = 0; j < num_errors; j++) {
sentry = metrics_store_add(the_store, rentry->type, rentry->name,
rentry->help);
metrics_store_entry_add_label(sentry, record_label);
metrics_store_entry_add_label(sentry,
metrics_format_label("reason", errors[j].name));
metrics_store_entry_update(sentry,
rep_hist_get_n_dns_error(dns_types[i].type, errors[j].key));
}
tor_free(record_label);
}
}
/** Fill function for the RELAY_METRICS_NUM_DNS metrics. */
static void
fill_dns_query_values(void)
{
metrics_store_entry_t *sentry;
const relay_metrics_entry_t *rentry =
&base_metrics[RELAY_METRICS_NUM_DNS];
for (size_t i = 0; i < num_dns_types; i++) {
/* Dup the label because metrics_format_label() returns a pointer to a
* string on the stack and we need that label for all metrics. */
char *record_label =
tor_strdup(metrics_format_label("record", dns_types[i].name));
sentry = metrics_store_add(the_store, rentry->type, rentry->name,
rentry->help);
metrics_store_entry_add_label(sentry, record_label);
metrics_store_entry_update(sentry,
rep_hist_get_n_dns_request(dns_types[i].type));
tor_free(record_label);
}
}
/** Fill function for the RELAY_METRICS_NUM_GLOBAL_RW_LIMIT metrics. */
static void
fill_global_bw_limit_values(void)

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@ -23,6 +23,10 @@ typedef enum {
RELAY_METRICS_NUM_SOCKETS = 2,
/** Number of global connection rate limit. */
RELAY_METRICS_NUM_GLOBAL_RW_LIMIT = 3,
/** Number of DNS queries. */
RELAY_METRICS_NUM_DNS = 4,
/** Number of DNS query errors. */
RELAY_METRICS_NUM_DNS_ERRORS = 5,
} relay_metrics_key_t;
/** The metadata of a relay metric. */