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Code Issues Releases Wiki Activity

Added option for disabling stale-answer-client-timeout

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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);

25
lib/isccfg/namedconf.c
View File

@@ -1899,6 +1899,28 @@ static cfg_type_t cfg_type_dns64 = { "dns64", cfg_parse_netprefix_map,
cfg_print_map, cfg_doc_map,
&cfg_rep_map, dns64_clausesets };
static const char *staleanswerclienttimeout_enums[] = { "disabled", "off",
NULL };
static isc_result_t
parse_staleanswerclienttimeout(cfg_parser_t *pctx, const cfg_type_t *type,
cfg_obj_t **ret) {
return (cfg_parse_enum_or_other(pctx, type, &cfg_type_uint32, ret));
}
static void
doc_staleanswerclienttimeout(cfg_printer_t *pctx, const cfg_type_t *type) {
cfg_doc_enum_or_other(pctx, type, &cfg_type_uint32);
}
static cfg_type_t cfg_type_staleanswerclienttimeout = {
"staleanswerclienttimeout",
parse_staleanswerclienttimeout,
cfg_print_ustring,
doc_staleanswerclienttimeout,
&cfg_rep_string,
staleanswerclienttimeout_enums
};
/*%
* Clauses that can be found within the 'view' statement,
* with defaults in the 'options' statement.
@@ -2027,7 +2049,8 @@ static cfg_clausedef_t view_clauses[] = {
{ "servfail-ttl", &cfg_type_duration, 0 },
{ "sortlist", &cfg_type_bracketed_aml, 0 },
{ "stale-answer-enable", &cfg_type_boolean, 0 },
{ "stale-answer-client-timeout", &cfg_type_uint32, 0 },
{ "stale-answer-client-timeout", &cfg_type_staleanswerclienttimeout,
0 },
{ "stale-answer-ttl", &cfg_type_duration, 0 },
{ "stale-cache-enable", &cfg_type_boolean, 0 },
{ "stale-refresh-time", &cfg_type_duration, 0 },