From: Alessio Podda <alessio@isc.org>
Date: Tue, 23 Dec 2025 15:38:53 +0000 (+0100)
Subject: Remove rrset-order cyclic from the default config, with shim
X-Git-Tag: v9.21.18~35^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=78588981df29309e4d7682d3355fefbbfba9f0c1;p=thirdparty%2Fbind9.git

Remove rrset-order cyclic from the default config, with shim

Currently we add an rrset-order cyclic statement to the default config.
Since the rrset-order allows matching a subset of all names, it must
be implemented with a string comparison against a wildcard, and since
the statement applies per rrset, this can result in millions of
comparisons per second on a busy authoritative server.

This commit removes rrset-order from the default config, but adds back
a code shim in query_setorder to preserve the previous behaviour.
---

diff --git a/bin/include/defaultconfig.h b/bin/include/defaultconfig.h
index 8e247572607..fb1ede220cc 100644
--- a/bin/include/defaultconfig.h
+++ b/bin/include/defaultconfig.h
@@ -79,7 +79,7 @@ options {\n\
 	request-zoneversion false;\n\
 	resolver-query-timeout 10;\n\
 #	responselog <boolean>;\n\
-	rrset-order { order cyclic; };\n\
+#	rrset-order { order cyclic; };\n\
 	secroots-file \"named.secroots\";\n\
 	send-cookie true;\n\
 	serial-query-rate 20;\n\
diff --git a/bin/named/server.c b/bin/named/server.c
index 6e1757cce08..09caf23d554 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -4620,20 +4620,27 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 	 *	Configure the views rrset-order.
 	 */
 	{
-		const cfg_obj_t *rrsetorder = NULL;
-
-		(void)named_config_get(maps, "rrset-order", &rrsetorder);
-		dns_order_create(mctx, &order);
-		CFG_LIST_FOREACH(rrsetorder, element) {
-			const cfg_obj_t *ent = cfg_listelt_value(element);
-
-			CHECK(configure_order(order, ent));
-		}
+		/*
+		 * Detach the old order
+		 */
 		if (view->order != NULL) {
 			dns_order_detach(&view->order);
 		}
-		dns_order_attach(order, &view->order);
-		dns_order_detach(&order);
+
+		const cfg_obj_t *rrsetorder = NULL;
+		if (ISC_R_SUCCESS ==
+		    named_config_get(maps, "rrset-order", &rrsetorder))
+		{
+			dns_order_create(mctx, &order);
+			CFG_LIST_FOREACH(rrsetorder, element) {
+				const cfg_obj_t *ent =
+					cfg_listelt_value(element);
+
+				CHECK(configure_order(order, ent));
+			}
+			dns_order_attach(order, &view->order);
+			dns_order_detach(&order);
+		}
 	}
 	/*
 	 * Copy the aclenv object.
diff --git a/lib/ns/query.c b/lib/ns/query.c
index e704db3f30e..b23db80903b 100644
--- a/lib/ns/query.c
+++ b/lib/ns/query.c
@@ -2212,6 +2212,15 @@ query_setorder(query_ctx_t *qctx, dns_name_t *name, dns_rdataset_t *rdataset) {
 	if (order != NULL) {
 		rdataset->attributes.order = dns_order_find(
 			order, name, rdataset->type, rdataset->rdclass);
+	} else {
+		/*
+		 * For backward compatibility reasons, we need to behave as if
+		 * rrset-order: cyclic was set when no order is configured.
+		 *
+		 * This was done through the default config, but it came at a
+		 * speed penalty.
+		 */
+		rdataset->attributes.order = dns_order_cyclic;
 	}
 }