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Code Issues Releases Wiki Activity

Added option for disabling stale-answer-client-timeout

Browse Source 
This commit allows to specify "disabled" or "off" in
stale-answer-client-timeout statement. The logic to support this
behavior will be added in the subsequent commits.

This commit also ensures an upper bound to stale-answer-client-timeout
which equals to one second less than 'resolver-query-timeout'.
This commit is contained in:
Diego Fronza
2020-12-18 16:24:56 -03:00
parent a12bf4b61b
commit 0ad6f594f6
2 changed files with 58 additions and 2 deletions
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35
bin/named/server.c
View File

@@ -4488,7 +4488,19 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
obj = NULL;
result = named_config_get(maps, "stale-answer-client-timeout", &obj);
INSIST(result == ISC_R_SUCCESS);
view->staleanswerclienttimeout = cfg_obj_asuint32(obj);
if (cfg_obj_isstring(obj)) {
/*
* The only string values available for this option
* are "disabled" and "off".
* We use (uint32_t) -1 to represent disabled since
* a value of zero means that stale data can be used
* to promptly answer the query, while an attempt to
* refresh the RRset will still be made in background.
*/
view->staleanswerclienttimeout = (uint32_t)-1;
} else {
view->staleanswerclienttimeout = cfg_obj_asuint32(obj);
}
obj = NULL;
result = named_config_get(maps, "stale-refresh-time", &obj);
@@ -4779,6 +4791,27 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
query_timeout = cfg_obj_asuint32(obj);
dns_resolver_settimeout(view->resolver, query_timeout);
/*
* Adjust stale-answer-client-timeout upper bound
* to be resolver-query-timeout - 1s.
* This assignment is safe as dns_resolver_settimeout()
* ensures that resolver->querytimeout value will be in the
* [MINIMUM_QUERY_TIMEOUT, MAXIMUM_QUERY_TIMEOUT] range and
* MINIMUM_QUERY_TIMEOUT is > 1000 (in ms).
*/
if (view->staleanswerclienttimeout != (uint32_t)-1 &&
view->staleanswerclienttimeout >
(dns_resolver_gettimeout(view->resolver) - 1000))
{
view->staleanswerclienttimeout =
dns_resolver_gettimeout(view->resolver) - 1000;
isc_log_write(
named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
NAMED_LOGMODULE_SERVER, ISC_LOG_WARNING,
"stale-answer-client-timeout adjusted to %" PRIu32,
view->staleanswerclienttimeout);
}
/* Specify whether to use 0-TTL for negative response for SOA query */
dns_resolver_setzeronosoattl(view->resolver, zero_no_soattl);