Shutdown the fetch context after canceling the last fetch

Currently, the fetch context will continue running even when the last
fetch (response) has been removed from the context, so named can process
and cache the answer.  This can lead to a situation where the number of
outgoing recursing clients exceeds the the configured number for
recursive-clients.

Be more stringent about the recursive-clients limit and shutdown the
fetch context immediately after the last fetch has been canceled from
that particular fetch context.

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index bc2d0bd519d5940f0449c97189ae38bbe9468dc0..e612eb7bb3e96b17e6cfa0fc13b699d0d2ee8770 100644 (file)
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -11210,10 +11210,9 @@ dns_resolver_cancelfetch(dns_fetch_t *fetch) {
                isc_task_sendanddetach(&etask, ISC_EVENT_PTR(&event_fetchdone));
        }
 
-       /*
-        * The fctx continues running even if no fetches remain;
-        * the answer is still cached.
-        */
+       if (ISC_LIST_EMPTY(fctx->events)) {
+               fctx_shutdown(fctx);
+       }
        UNLOCK(&res->buckets[fctx->bucketnum].lock);
 }