generic-library/bionic
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Fail queries fast if no DNS servers are configured.

Browse Source 
When no DNS servers are configured (and thus there is no chance
that the DNS query will suceed), res_nsend returns early, but
it does not tell the cache that the query has failed.
Therefore, if the caller retries the query, it will block for
PENDING_REQUEST_TIMEOUT (= 20 seconds) waiting for the "existing
query" (which isn't actually doing anything) to complete.

Bug: 18240188
Bug: 18327075
Change-Id: I0df13ff4a17ee65e640be96695a3af31b020963a
This commit is contained in:
Lorenzo Colitti 2014-11-28 20:03:23 +09:00
parent 432f645887
commit e5477f83b0
1 changed files with 4 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
libc/dns/resolv/res_send.c
View File

@ -402,6 +402,10 @@ res_nsend(res_state statp,
}
if (statp->nscount == 0) {
// We have no nameservers configured, so there's no point trying.
// Tell the cache the query failed, or any retries and anyone else asking the same
// question will block for PENDING_REQUEST_TIMEOUT seconds instead of failing fast.
_resolv_cache_query_failed(statp->netid, buf, buflen);
errno = ESRCH;
return (-1);
}