Check 'stale-refresh-time' when sharing cache between views

This commit ensures that, along with previous restrictions, a cache is
shareable between views only if their 'stale-refresh-time' value are
equal.

bin/named/server.c

@@ -1869,7 +1869,7 @@ cache_reusable(dns_view_t *originview, dns_view_t *view,
 static bool
 cache_sharable(dns_view_t *originview, dns_view_t *view,
 	       bool new_zero_no_soattl, uint64_t new_max_cache_size,
-	       uint32_t new_stale_ttl) {
+	       uint32_t new_stale_ttl, uint32_t new_stale_refresh_time) {
 	/*
 	 * If the cache cannot even reused for the same view, it cannot be
 	 * shared with other views.
@@ -1883,6 +1883,7 @@ cache_sharable(dns_view_t *originview, dns_view_t *view,
 	 * the sharing views.
 	 */
 	if (dns_cache_getservestalettl(originview->cache) != new_stale_ttl ||
+	    dns_cache_getservestalerefresh(originview->cache) != new_stale_refresh_time ||
 	    dns_cache_getcachesize(originview->cache) != new_max_cache_size)
 	{
 		return (false);
@@ -4435,7 +4436,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 	nsc = cachelist_find(cachelist, cachename, view->rdclass);
 	if (nsc != NULL) {
 		if (!cache_sharable(nsc->primaryview, view, zero_no_soattl,
-				    max_cache_size, max_stale_ttl))
+				    max_cache_size, max_stale_ttl, stale_refresh_time))
 		{
 			isc_log_write(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
 				      NAMED_LOGMODULE_SERVER, ISC_LOG_ERROR,

lib/dns/cache.c

@@ -142,6 +142,7 @@ struct dns_cache {
 	char **db_argv;
 	size_t size;
 	dns_ttl_t serve_stale_ttl;
+	dns_ttl_t serve_stale_refresh;
 	isc_stats_t *stats;
 
 	/* Locked by 'filelock'. */
@@ -1000,12 +1001,27 @@ dns_cache_getservestalettl(dns_cache_t *cache) {
 }
 
 void
-dns_cache_setservestalerefresh(dns_cache_t *cache, uint32_t interval) {
+dns_cache_setservestalerefresh(dns_cache_t *cache, dns_ttl_t interval) {
 	REQUIRE(VALID_CACHE(cache));
 
+	LOCK(&cache->lock);
+	cache->serve_stale_refresh = interval;
+	UNLOCK(&cache->lock);
+
 	(void)dns_db_setservestalerefresh(cache->db, interval);
 }
 
+dns_ttl_t
+dns_cache_getservestalerefresh(dns_cache_t *cache) {
+	isc_result_t result;
+	dns_ttl_t interval;
+
+	REQUIRE(VALID_CACHE(cache));
+
+	result = dns_db_getservestalerefresh(cache->db, &interval);
+	return (result == ISC_R_SUCCESS ? interval : 0);
+}
+
 /*
  * The cleaner task is shutting down; do the necessary cleanup.
  */

lib/dns/include/dns/cache.h

@@ -256,7 +256,7 @@ dns_cache_getservestalettl(dns_cache_t *cache);
  */
 
 void
-dns_cache_setservestalerefresh(dns_cache_t *cache, uint32_t interval);
+dns_cache_setservestalerefresh(dns_cache_t *cache, dns_ttl_t interval);
 /*%<
  * Sets the length of time to wait before attempting to refresh a rrset
  * if a previous attempt in doing so has failed.
@@ -267,6 +267,16 @@ dns_cache_setservestalerefresh(dns_cache_t *cache, uint32_t interval);
  *\li	'cache' to be valid.
  */
 
+dns_ttl_t
+dns_cache_getservestalerefresh(dns_cache_t *cache);
+/*%<
+ * Gets the 'stale-refresh-time' value, set by a previous call to
+ * 'dns_cache_setservestalerefresh'.
+ *
+ * Requires:
+ *\li	'cache' to be valid.
+ */
+
 isc_result_t
 dns_cache_flush(dns_cache_t *cache);
 /*%<