Add recursionquota_attach*()

Add a set of new helper functions for attaching to the recursion quota
in order to reduce code duplication and to ensure that the recursive
clients counter is always adjusted properly.  Since some callers
(query_prefetch(), query_rpzfetch()) treat exceeding the soft quota as
an error while others (check_recursionquota()) do not, also add two
wrapper functions whose names help convey their purpose, in order to
improve code readability.

diff --git a/lib/ns/query.c b/lib/ns/query.c
index 81e07cb46eadc22d97023280b87f3d1b425589b7..0f9cce64f7d3a215d51f437a6a41d9e7b342f9e6 100644 (file)
--- a/lib/ns/query.c
+++ b/lib/ns/query.c
@@ -2477,6 +2477,51 @@ free_devent(ns_client_t *client, isc_event_t **eventp,
        isc_event_free(eventp);
 }
 
+static isc_result_t
+recursionquota_attach(ns_client_t *client, bool soft_limit) {
+       isc_result_t result;
+
+       if (client->recursionquota != NULL) {
+               return (ISC_R_SUCCESS);
+       }
+
+       result = isc_quota_attach(&client->manager->sctx->recursionquota,
+                                 &client->recursionquota);
+       switch (result) {
+       case ISC_R_SUCCESS:
+               break;
+       case ISC_R_SOFTQUOTA:
+               if (soft_limit) {
+                       /*
+                        * Exceeding soft quota was allowed, so continue as if
+                        * 'result' was ISC_R_SUCCESS while retaining the
+                        * original result code.
+                        */
+                       break;
+               }
+
+               isc_quota_detach(&client->recursionquota);
+               FALLTHROUGH;
+       default:
+               return (result);
+       }
+
+       ns_stats_increment(client->manager->sctx->nsstats,
+                          ns_statscounter_recursclients);
+
+       return (result);
+}
+
+static isc_result_t
+recursionquota_attach_hard(ns_client_t *client) {
+       return (recursionquota_attach(client, false));
+}
+
+static isc_result_t
+recursionquota_attach_soft(ns_client_t *client) {
+       return (recursionquota_attach(client, true));
+}
+
 static void
 recursionquota_detach(ns_client_t *client) {
        if (client->recursionquota != NULL) {
@@ -2535,24 +2580,11 @@ query_prefetch(ns_client_t *client, dns_name_t *qname,
                return;
        }
 
-       if (client->recursionquota == NULL) {
-               result =
-                       isc_quota_attach(&client->manager->sctx->recursionquota,
-                                        &client->recursionquota);
-               switch (result) {
-               case ISC_R_SUCCESS:
-                       break;
-               case ISC_R_SOFTQUOTA:
-                       isc_quota_detach(&client->recursionquota);
-                       FALLTHROUGH;
-               default:
-                       return;
-               }
+       result = recursionquota_attach_hard(client);
+       if (result != ISC_R_SUCCESS) {
+               return;
        }
 
-       ns_stats_increment(client->manager->sctx->nsstats,
-                          ns_statscounter_recursclients);
-
        tmprdataset = ns_client_newrdataset(client);
 
        if (!TCP(client)) {
@@ -2747,24 +2779,11 @@ query_rpzfetch(ns_client_t *client, dns_name_t *qname, dns_rdatatype_t type) {
                return;
        }
 
-       if (client->recursionquota == NULL) {
-               result =
-                       isc_quota_attach(&client->manager->sctx->recursionquota,
-                                        &client->recursionquota);
-               switch (result) {
-               case ISC_R_SUCCESS:
-                       break;
-               case ISC_R_SOFTQUOTA:
-                       isc_quota_detach(&client->recursionquota);
-                       FALLTHROUGH;
-               default:
-                       return;
-               }
+       result = recursionquota_attach_hard(client);
+       if (result != ISC_R_SUCCESS) {
+               return;
        }
 
-       ns_stats_increment(client->manager->sctx->nsstats,
-                          ns_statscounter_recursclients);
-
        tmprdataset = ns_client_newrdataset(client);
 
        if (!TCP(client)) {
@@ -6318,9 +6337,7 @@ check_recursionquota(ns_client_t *client) {
         * connection was accepted (if allowed by the TCP quota).
         */
        if (client->recursionquota == NULL) {
-               result =
-                       isc_quota_attach(&client->manager->sctx->recursionquota,
-                                        &client->recursionquota);
+               result = recursionquota_attach_soft(client);
                if (result == ISC_R_SOFTQUOTA) {
                        isc_stdtime_t now;
                        isc_stdtime_get(&now);
@@ -6403,9 +6420,6 @@ ns_query_recurse(ns_client_t *client, dns_rdatatype_t qtype, dns_name_t *qname,
                return (result);
        }
 
-       ns_stats_increment(client->manager->sctx->nsstats,
-                          ns_statscounter_recursclients);
-
        /*
         * Invoke the resolver.
         */
@@ -6811,9 +6825,6 @@ ns_query_hookasync(query_ctx_t *qctx, ns_query_starthookasync_t runasync,
                goto cleanup;
        }
 
-       ns_stats_increment(client->manager->sctx->nsstats,
-                          ns_statscounter_recursclients);
-
        saved_qctx = isc_mem_get(client->manager->mctx, sizeof(*saved_qctx));
        qctx_save(qctx, saved_qctx);
        result = runasync(saved_qctx, client->manager->mctx, arg,