Use stale data also if we are not resuming

Before this change, BIND will only fallback to using stale data if
there was an actual attempt to resolve the query. Then on a timeout,
the stale data from cache becomes eligible.

This commit changes this so that on any unexpected error stale data
becomes eligble (you would still have to have 'stale-answer-enable'
enabled of course).

If there is no stale data, this may return in an error again, so don't
loop on stale data lookup attempts. If the DNS_DBFIND_STALEOK flag is
set, this means we already tried to lookup stale data, so if that is
the case, don't use stale again.

diff --git a/lib/ns/query.c b/lib/ns/query.c
index f413ddee19f2bd18ab50bea7b7b98eab02926311..2248e4b0b3c9101b7b0876a5300641431e082c33 100644 (file)
--- a/lib/ns/query.c
+++ b/lib/ns/query.c
@@ -7441,6 +7441,14 @@ root_key_sentinel_return_servfail(query_ctx_t *qctx, isc_result_t result) {
  */
 static bool
 query_usestale(query_ctx_t *qctx) {
+       if ((qctx->client->query.dboptions & DNS_DBFIND_STALEOK) != 0) {
+               /*
+                * Query was already using stale, if that didn't work the
+                * last time, it won't work this time either.
+                */
+               return (false);
+       }
+
        qctx_clean(qctx);
        qctx_freedata(qctx);
 
@@ -7548,7 +7556,7 @@ query_gotanswer(query_ctx_t *qctx, isc_result_t res) {
                         "query_gotanswer: unexpected error: %s",
                         isc_result_totext(result));
                CCTRACE(ISC_LOG_ERROR, errmsg);
-               if (qctx->resuming && query_usestale(qctx)) {
+               if (query_usestale(qctx)) {
                        /*
                         * If serve-stale is enabled, query_usestale() already
                         * set up 'qctx' for looking up a stale response.