From: Mark Andrews <marka@isc.org>
Date: Mon, 21 Nov 2022 00:59:45 +0000 (+1100)
Subject: Remove different zero TTL handling for rdataset iterator
X-Git-Tag: v9.19.8~7^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1a39328feb488c1d406a1b2d15dc6e0f882dce55;p=thirdparty%2Fbind9.git

Remove different zero TTL handling for rdataset iterator

Zero TTL handling does not need to be different for 'rdatasetiter_first'
and 'rdatasetiter_next' and it interacts badly with 'bind_rdatadataset'
which makes different determinations.
---

diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c
index 388e7540376..f765518f11e 100644
--- a/lib/dns/rbtdb.c
+++ b/lib/dns/rbtdb.c
@@ -8840,6 +8840,35 @@ rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp) {
 	*iteratorp = NULL;
 }
 
+static bool
+iterator_active(dns_rbtdb_t *rbtdb, rbtdb_rdatasetiter_t *rbtiterator,
+		rdatasetheader_t *header) {
+	dns_ttl_t stale_ttl = header->rdh_ttl + STALE_TTL(header, rbtdb);
+
+	/*
+	 * Is this a "this rdataset doesn't exist" record?
+	 */
+	if (NONEXISTENT(header)) {
+		return (false);
+	}
+
+	/*
+	 * If this is a zone or this header still active then return it.
+	 */
+	if (!IS_CACHE(rbtdb) || ACTIVE(header, rbtiterator->common.now)) {
+		return (true);
+	}
+
+	/*
+	 * If we are not returning stale records or the rdataset is
+	 * too old don't return it.
+	 */
+	if (!STALEOK(rbtiterator) || (rbtiterator->common.now > stale_ttl)) {
+		return (false);
+	}
+	return (true);
+}
+
 static isc_result_t
 rdatasetiter_first(dns_rdatasetiter_t *iterator) {
 	rbtdb_rdatasetiter_t *rbtiterator = (rbtdb_rdatasetiter_t *)iterator;
@@ -8847,27 +8876,14 @@ rdatasetiter_first(dns_rdatasetiter_t *iterator) {
 	dns_rbtnode_t *rbtnode = rbtiterator->common.node;
 	rbtdb_version_t *rbtversion = rbtiterator->common.version;
 	rdatasetheader_t *header, *top_next;
-	rbtdb_serial_t serial;
-	isc_stdtime_t now;
+	rbtdb_serial_t serial = IS_CACHE(rbtdb) ? 1 : rbtversion->serial;
 	isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
 
-	if (IS_CACHE(rbtdb)) {
-		serial = 1;
-		now = rbtiterator->common.now;
-	} else {
-		serial = rbtversion->serial;
-		now = 0;
-	}
-
 	NODE_RDLOCK(&rbtdb->node_locks[rbtnode->locknum].lock, &nlocktype);
 
 	for (header = rbtnode->data; header != NULL; header = top_next) {
 		top_next = header->next;
 		do {
-			dns_ttl_t stale_ttl = header->rdh_ttl;
-			if (STALEOK(rbtiterator)) {
-				stale_ttl += STALE_TTL(header, rbtdb);
-			}
 			if (EXPIREDOK(rbtiterator)) {
 				if (!NONEXISTENT(header)) {
 					break;
@@ -8875,17 +8891,9 @@ rdatasetiter_first(dns_rdatasetiter_t *iterator) {
 				header = header->down;
 			} else if (header->serial <= serial && !IGNORE(header))
 			{
-				/*
-				 * Is this a "this rdataset doesn't exist"
-				 * record?  Or is it too old in the cache?
-				 *
-				 * Note: unlike everywhere else, we
-				 * check for now > header->rdh_ttl instead
-				 * of ">=".  This allows ANY and RRSIG
-				 *  queries for 0 TTL rdatasets to work.
-				 */
-				if (NONEXISTENT(header) ||
-				    (now != 0 && now > stale_ttl)) {
+				if (!iterator_active(rbtdb, rbtiterator,
+						     header))
+				{
 					header = NULL;
 				}
 				break;
@@ -8916,8 +8924,7 @@ rdatasetiter_next(dns_rdatasetiter_t *iterator) {
 	dns_rbtnode_t *rbtnode = rbtiterator->common.node;
 	rbtdb_version_t *rbtversion = rbtiterator->common.version;
 	rdatasetheader_t *header, *top_next;
-	rbtdb_serial_t serial;
-	isc_stdtime_t now;
+	rbtdb_serial_t serial = IS_CACHE(rbtdb) ? 1 : rbtversion->serial;
 	rbtdb_rdatatype_t type, negtype;
 	dns_rdatatype_t rdtype, covers;
 	isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
@@ -8928,14 +8935,6 @@ rdatasetiter_next(dns_rdatasetiter_t *iterator) {
 		return (ISC_R_NOMORE);
 	}
 
-	if (IS_CACHE(rbtdb)) {
-		serial = 1;
-		now = rbtiterator->common.now;
-	} else {
-		serial = rbtversion->serial;
-		now = 0;
-	}
-
 	NODE_RDLOCK(&rbtdb->node_locks[rbtnode->locknum].lock, &nlocktype);
 
 	type = header->type;
@@ -8969,10 +8968,6 @@ rdatasetiter_next(dns_rdatasetiter_t *iterator) {
 	for (; header != NULL; header = top_next) {
 		top_next = header->next;
 		do {
-			dns_ttl_t stale_ttl = header->rdh_ttl;
-			if (STALEOK(rbtiterator)) {
-				stale_ttl += STALE_TTL(header, rbtdb);
-			}
 			if (expiredok) {
 				if (!NONEXISTENT(header)) {
 					break;
@@ -8980,17 +8975,9 @@ rdatasetiter_next(dns_rdatasetiter_t *iterator) {
 				header = header->down;
 			} else if (header->serial <= serial && !IGNORE(header))
 			{
-				/*
-				 * Is this a "this rdataset doesn't
-				 * exist" record?
-				 *
-				 * Note: unlike everywhere else, we
-				 * check for now > header->ttl instead
-				 * of ">=".  This allows ANY and RRSIG
-				 * queries for 0 TTL rdatasets to work.
-				 */
-				if (NONEXISTENT(header) ||
-				    (now != 0 && now > stale_ttl)) {
+				if (!iterator_active(rbtdb, rbtiterator,
+						     header))
+				{
 					header = NULL;
 				}
 				break;