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Code Issues Releases Wiki Activity

3333. [bug] Setting resolver-query-timeout too low can cause

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named to not recover if it looses connectivity.
                        [RT #29623]
This commit is contained in:
Mark Andrews
2012-06-08 12:34:33 +10:00
parent 0ef5a17e84
commit 7310c0b1ee
5 changed files with 47 additions and 17 deletions
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50
lib/dns/resolver.c
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@@ -106,8 +106,21 @@
#define QTRACE(m)
#endif
#define US_PER_SEC 1000000U
/*
* The maximum time we will wait for a single query.
*/
#define MAX_SINGLE_QUERY_TIMEOUT 9U
#define MAX_SINGLE_QUERY_TIMEOUT_US (MAX_SINGLE_QUERY_TIMEOUT*US_PER_SEC)
/*
* We need to allow a individual query time to complete / timeout.
*/
#define MINIMUM_QUERY_TIMEOUT (MAX_SINGLE_QUERY_TIMEOUT + 1U)
/* The default time in seconds for the whole query to live. */
#ifndef DEFAULT_QUERY_TIMEOUT
#define DEFAULT_QUERY_TIMEOUT 10 /* The default time in seconds for the whole query to live. */
#define DEFAULT_QUERY_TIMEOUT MINIMUM_QUERY_TIMEOUT
#endif
#ifndef MAXIMUM_QUERY_TIMEOUT
@@ -827,8 +840,8 @@ fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
*/
INSIST(no_response);
rtt = query->addrinfo->srtt + 200000;
if (rtt > 10000000)
rtt = 10000000;
if (rtt > MAX_SINGLE_QUERY_TIMEOUT_US)
rtt = MAX_SINGLE_QUERY_TIMEOUT_US;
/*
* Replace the current RTT with our value.
*/
@@ -1343,12 +1356,18 @@ fctx_setretryinterval(fetchctx_t *fctx, unsigned int rtt) {
us = (800000 << (fctx->restarts - 2));
/*
* Double the round-trip time.
* Add a fudge factor to the expected rtt based on the current
* estimate.
*/
rtt *= 2;
if (rtt < 50000)
rtt += 50000;
else if (rtt < 100000)
rtt += 100000;
else
rtt += 200000;
/*
* Always wait for at least the doubled round-trip time.
* Always wait for at least the expected rtt.
*/
if (us < rtt)
us = rtt;
@@ -1356,11 +1375,11 @@ fctx_setretryinterval(fetchctx_t *fctx, unsigned int rtt) {
/*
* But don't ever wait for more than 10 seconds.
*/
if (us > 10000000)
us = 10000000;
if (us > MAX_SINGLE_QUERY_TIMEOUT_US)
us = MAX_SINGLE_QUERY_TIMEOUT_US;
seconds = us / 1000000;
us -= seconds * 1000000;
seconds = us / US_PER_SEC;
us -= seconds * US_PER_SEC;
isc_interval_set(&fctx->interval, seconds, us * 1000);
}
@@ -1382,6 +1401,11 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
task = res->buckets[fctx->bucketnum].task;
srtt = addrinfo->srtt;
/*
* A forwarder needs to make multiple queries. Give it at least
* a second to do these in.
*/
if (ISFORWARDER(addrinfo) && srtt < 1000000)
srtt = 1000000;
@@ -8191,8 +8215,8 @@ dns_resolver_logfetch(dns_fetch_t *fetch, isc_log_t *lctx,
"timeout:%u,lame:%u,neterr:%u,badresp:%u,"
"adberr:%u,findfail:%u,valfail:%u]",
__FILE__, fctx->exitline, fctx->info,
fctx->duration / 1000000,
fctx->duration % 1000000,
fctx->duration / US_PER_SEC,
fctx->duration % US_PER_SEC,
isc_result_totext(fctx->result),
isc_result_totext(fctx->vresult), domainbuf,
fctx->referrals, fctx->restarts,
@@ -8797,6 +8821,8 @@ dns_resolver_settimeout(dns_resolver_t *resolver, unsigned int seconds) {
seconds = DEFAULT_QUERY_TIMEOUT;
if (seconds > MAXIMUM_QUERY_TIMEOUT)
seconds = MAXIMUM_QUERY_TIMEOUT;
if (seconds < MINIMUM_QUERY_TIMEOUT)
seconds = MINIMUM_QUERY_TIMEOUT;
resolver->query_timeout = seconds;
}