Reuse recursion type code for refresh stale RRset

Refreshing a stale RRset is similar to prefetching an RRset, so
reuse the existing code. When refreshing an RRset we need to clear
all db options related to serve-stale so that stale RRsets in cache
are ignored during the refresh.

We no longer need to set the "nodetach" flag, because the refresh
fetch is now a "fetch and forget". So we can detach from the client
in the query_send().

This code will break some serve-stale test cases, this will be fixed
in the successor commit.

TODO: add explanation why the serve-stale test cases fail.

diff --git a/lib/ns/query.c b/lib/ns/query.c
index 8039d0f439a61b51e43790b3b3f7cd5c78839312..6cb95f676be3a12036c4123d6d9a410d77feaa58 100644 (file)
--- a/lib/ns/query.c
+++ b/lib/ns/query.c
@@ -2543,6 +2543,7 @@ cleanup_after_fetch(isc_task_t *task, isc_event_t *event, const char *ctracestr,
        fetchp = &client->query.recursions[recursion_type].fetch;
 
        LOCK(&client->query.fetchlock);
+
        if (*fetchp != NULL) {
                INSIST(devent->fetch == *fetchp);
                *fetchp = NULL;
@@ -2550,7 +2551,6 @@ cleanup_after_fetch(isc_task_t *task, isc_event_t *event, const char *ctracestr,
        UNLOCK(&client->query.fetchlock);
 
        recursionquotatype_detach(client, recursion_type);
-
        free_devent(client, &event, &devent);
        isc_nmhandle_detach(handlep);
 }
@@ -2566,8 +2566,9 @@ rpzfetch_done(isc_task_t *task, isc_event_t *event) {
 }
 
 static void
-refresh_done(isc_task_t *task, isc_event_t *event) {
-       cleanup_after_fetch(task, event, "refresh_done", RECTYPE_REFRESH);
+stale_refresh_done(isc_task_t *task, isc_event_t *event) {
+       cleanup_after_fetch(task, event, "stale_refresh_done",
+                           RECTYPE_STALE_REFRESH);
 }
 
 /*
@@ -2611,9 +2612,9 @@ fetch_and_forget(ns_client_t *client, dns_name_t *qname, dns_rdatatype_t qtype,
                options = client->query.fetchoptions;
                action = rpzfetch_done;
                break;
-       case RECTYPE_REFRESH:
+       case RECTYPE_STALE_REFRESH:
                options = client->query.fetchoptions;
-               action = refresh_done;
+               action = stale_refresh_done;
                break;
        default:
                UNREACHABLE();
@@ -2655,19 +2656,29 @@ query_prefetch(ns_client_t *client, dns_name_t *qname,
                           ns_statscounter_prefetch);
 }
 
-/*
 static void
-query_refresh(ns_client_t *client, dns_name_t *qname,
-              dns_rdataset_t *rdataset) {
-       CTRACE(ISC_LOG_DEBUG(3), "query_refresh");
+query_stale_refresh(ns_client_t *client) {
+       dns_name_t *qname;
+
+       CTRACE(ISC_LOG_DEBUG(3), "query_stale_refresh");
 
-       if (FETCH_RECTYPE_REFRESH(client) != NULL) {
+       if (FETCH_RECTYPE_STALE_REFRESH(client) != NULL) {
                return;
        }
 
-       fetch_and_forget(client, qname, rdataset->type, RECTYPE_REFRESH);
+       client->query.dboptions &= ~(DNS_DBFIND_STALETIMEOUT |
+                                    DNS_DBFIND_STALEOK |
+                                    DNS_DBFIND_STALEENABLED);
+
+       if (client->query.origqname != NULL) {
+               qname = client->query.origqname;
+       } else {
+               qname = client->query.qname;
+       }
+
+       fetch_and_forget(client, qname, client->query.qtype,
+                        RECTYPE_STALE_REFRESH);
 }
-*/
 
 static void
 rpz_clean(dns_zone_t **zonep, dns_db_t **dbp, dns_dbnode_t **nodep,
@@ -5225,26 +5236,6 @@ qctx_init(ns_client_t *client, dns_fetchevent_t **eventp, dns_rdatatype_t qtype,
        CALL_HOOK_NORETURN(NS_QUERY_QCTX_INITIALIZED, qctx);
 }
 
-/*
- * Make 'dst' and exact copy of 'src', with exception of the
- * option field, which is reset to zero.
- * This function also attaches dst's view and db to the src's
- * view and cachedb.
- */
-static void
-qctx_copy(const query_ctx_t *qctx, query_ctx_t *dst) {
-       REQUIRE(qctx != NULL);
-       REQUIRE(dst != NULL);
-
-       memmove(dst, qctx, sizeof(*dst));
-       dst->view = NULL;
-       dst->db = NULL;
-       dst->options = 0;
-       dns_view_attach(qctx->view, &dst->view);
-       dns_db_attach(qctx->view->cachedb, &dst->db);
-       CCTRACE(ISC_LOG_DEBUG(3), "qctx_copy");
-}
-
 /*%
  * Clean up and disassociate the rdataset and node pointers in qctx.
  */
@@ -5749,54 +5740,6 @@ qctx_prepare_buffers(query_ctx_t *qctx, isc_buffer_t *buffer) {
        return (ISC_R_SUCCESS);
 }
 
-/*
- * Setup a new query context for resolving a query.
- *
- * This function is only called if both these conditions are met:
- *    1. BIND is configured with stale-answer-client-timeout 0.
- *    2. A stale RRset is found in cache during initial query
- *       database lookup.
- *
- * We continue with this function for refreshing/resolving an RRset
- * after answering a client with stale data.
- */
-static void
-query_refresh_rrset(query_ctx_t *orig_qctx) {
-       isc_buffer_t buffer;
-       query_ctx_t qctx;
-
-       REQUIRE(orig_qctx != NULL);
-       REQUIRE(orig_qctx->client != NULL);
-
-       qctx_copy(orig_qctx, &qctx);
-       qctx.client->query.dboptions &= ~(DNS_DBFIND_STALETIMEOUT |
-                                         DNS_DBFIND_STALEOK |
-                                         DNS_DBFIND_STALEENABLED);
-
-       /*
-        * We'll need some resources...
-        */
-       if (qctx_prepare_buffers(&qctx, &buffer) != ISC_R_SUCCESS) {
-               dns_db_detach(&qctx.db);
-               qctx_destroy(&qctx);
-               return;
-       }
-
-       /*
-        * Pretend we didn't find anything in cache.
-        */
-       (void)query_gotanswer(&qctx, ISC_R_NOTFOUND);
-
-       if (qctx.fname != NULL) {
-               ns_client_releasename(qctx.client, &qctx.fname);
-       }
-       if (qctx.rdataset != NULL) {
-               ns_client_putrdataset(qctx.client, &qctx.rdataset);
-       }
-
-       qctx_destroy(&qctx);
-}
-
 /*%
  * Perform a local database lookup, in either an authoritative or
  * cache database. If unable to answer, call ns_query_done(); otherwise
@@ -11548,12 +11491,7 @@ ns_query_done(query_ctx_t *qctx) {
        /*
         * Client may have been detached after query_send(), so
         * we test and store the flag state here, for safety.
-        * If we are refreshing the RRSet, we must not detach from the client
-        * in the query_send(), so we need to override the flag.
         */
-       if (qctx->refresh_rrset) {
-               qctx->client->nodetach = true;
-       }
        nodetach = qctx->client->nodetach;
        query_send(qctx->client);
 
@@ -11568,7 +11506,7 @@ ns_query_done(query_ctx_t *qctx) {
                 * refresh.
                 */
                message_clearrdataset(qctx->client->message, 0);
-               query_refresh_rrset(qctx);
+               query_stale_refresh(qctx->client);
        }
 
        if (!nodetach) {