From: Ondřej Surý <ondrej@isc.org>
Date: Wed, 14 Jan 2026 12:17:30 +0000 (+0100)
Subject: Remove useless .expire initialization from rdataslab
X-Git-Tag: v9.21.21~3^2~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=08a33a9cc94a241dc48addbd54f5a8f2419e32c5;p=thirdparty%2Fbind9.git

Remove useless .expire initialization from rdataslab

dns_rdataslab_fromrdataset() set .expire to rdataset->ttl, but the
only consumer (qpcache_addrdataset) immediately overwrote it with
now + rdataset->ttl.  Remove the redundant initialization and set the
expire time only once.
---

diff --git a/lib/dns/include/dns/rdataslab.h b/lib/dns/include/dns/rdataslab.h
index 51a179247b9..5b7e8ffc767 100644
--- a/lib/dns/include/dns/rdataslab.h
+++ b/lib/dns/include/dns/rdataslab.h
@@ -191,10 +191,8 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
  *
  * dns_rdataslab_fromrdataset() allocates space for a dns_slabheader object
  * and the memory needed for a raw slab, and partially initializes
- * it, setting the type, trust, and TTL fields to match rdataset->type,
- * rdataset->covers, rdataset->trust, and rdataset->ttl.  (Note that the
- * last field needs to be overridden when used in the cache database,
- * since cache headers use an expire time instead of a TTL.)
+ * it, setting the type, and trust fields to match rdataset->type,
+ * rdataset->covers, and rdataset->trust.
  *
  * Requires:
  *\li	'rdataset' is valid.
diff --git a/lib/dns/qpcache.c b/lib/dns/qpcache.c
index 2b6eaac8c3e..db0d4f99777 100644
--- a/lib/dns/qpcache.c
+++ b/lib/dns/qpcache.c
@@ -2874,11 +2874,9 @@ qpcache_addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
 	dns_slabheader_reset(newheader, node);
 
 	/*
-	 * By default, dns_rdataslab_fromrdataset() sets newheader->ttl
-	 * to the rdataset TTL. In the case of the cache, that's wrong;
-	 * we need it to be set to the expire time instead.
+	 * Set the correct expire time.
 	 */
-	setttl(newheader, rdataset->ttl + now);
+	setttl(newheader, now + rdataset->ttl);
 	if (rdataset->ttl == 0U) {
 		DNS_SLABHEADER_SETATTR(newheader, DNS_SLABHEADERATTR_ZEROTTL);
 	}
diff --git a/lib/dns/rdataslab.c b/lib/dns/rdataslab.c
index 64e955cad4e..e0a43e84347 100644
--- a/lib/dns/rdataslab.c
+++ b/lib/dns/rdataslab.c
@@ -110,7 +110,6 @@ newslab(dns_rdataset_t *rdataset, isc_mem_t *mctx, isc_region_t *region,
 	*header = (dns_slabheader_t){
 		.headers_link = CDS_LIST_HEAD_INIT(header->headers_link),
 		.trust = rdataset->trust,
-		.expire = rdataset->ttl,
 		.dirtylink = ISC_LINK_INITIALIZER,
 		.nitems = nitems,
 	};