Add expiration option 'cache_ttl'.

Defaults to 120 seconds.

1 files changed, 42 insertions, 38 deletions

diff --git a/cache.c b/cache.c
index 40c25ce..69d8545 100644
--- a/cache.c
+++ b/cache.c
@@ -19,6 +19,7 @@
 
 #include <isc/mem.h>
 #include <isc/result.h>
+#include <isc/time.h>
 #include <isc/util.h>
 
 #include <dns/rbt.h>
@@ -37,13 +38,13 @@
 struct ldap_cache {
 	isc_mem_t	*mctx;
 	dns_rbt_t	*rbt;
-	/* TODO: Add a timeout period setting. */
+	isc_interval_t	cache_ttl;
 };
 
 typedef struct {
 	isc_mem_t		*mctx;
 	ldapdb_rdatalist_t	rdatalist;
-	/* TODO: Add time of creation for expiration purposes. */
+	isc_time_t		valid_until;
 } cache_node_t;
 
 static void
@@ -59,54 +60,58 @@ cache_node_deleter(void *data, void *deleter_arg)
 }
 
 static isc_result_t
-cache_node_create(isc_mem_t *mctx, ldapdb_rdatalist_t rdatalist,
+cache_node_create(ldap_cache_t *cache, ldapdb_rdatalist_t rdatalist,
 		  cache_node_t **nodep)
 {
 	isc_result_t result;
 	cache_node_t *node;
 
-	REQUIRE(mctx != NULL);
+	REQUIRE(cache != NULL);
 	REQUIRE(nodep != NULL && *nodep == NULL);
 
-	CHECKED_MEM_GET_PTR(mctx, node);
+	CHECKED_MEM_GET_PTR(cache->mctx, node);
 	ZERO_PTR(node);
-	isc_mem_attach(mctx, &node->mctx);
+	isc_mem_attach(cache->mctx, &node->mctx);
 	node->rdatalist = rdatalist;
+	CHECK(isc_time_nowplusinterval(&node->valid_until, &cache->cache_ttl));
 
 	*nodep = node;
 	return ISC_R_SUCCESS;
 
 cleanup:
-	SAFE_MEM_PUT_PTR(mctx, node);
+	SAFE_MEM_PUT_PTR(cache->mctx, node);
 
 	return result;
 }
 
-/*
- * TODO: Add setting saying if we want to enable cache, if not, then
- * cache->rbt must be set to NULL.
- */
 isc_result_t
 new_ldap_cache(isc_mem_t *mctx, ldap_cache_t **cachep,
 	       const char * const *argv)
 {
 	isc_result_t result;
 	ldap_cache_t *cache = NULL;
-
-	UNUSED(argv);
+	unsigned int cache_ttl;
+	setting_t cache_settings[] = {
+		{ "cache_ttl", default_uint(120) },
+		end_of_settings
+	};
 
 	REQUIRE(cachep != NULL && *cachep == NULL);
 
+	cache_settings[0].target = &cache_ttl;
+	CHECK(set_settings(cache_settings, argv));
+
 	CHECKED_MEM_GET_PTR(mctx, cache);
 	ZERO_PTR(cache);
 	isc_mem_attach(mctx, &cache->mctx);
 
-	if (1) {
+	isc_interval_set(&cache->cache_ttl, cache_ttl, 0);
+
+	if (cache_ttl) {
 		CHECK(dns_rbt_create(mctx, cache_node_deleter, NULL,
 				     &cache->rbt));
 	}
 
-
 	*cachep = cache;
 	return ISC_R_SUCCESS;
 
@@ -134,7 +139,6 @@ destroy_ldap_cache(ldap_cache_t **cachep)
 	*cachep = NULL;
 }
 
-/* TODO: Implement expiration. */
 isc_result_t
 cached_ldap_rdatalist_get(isc_mem_t *mctx, ldap_cache_t *cache,
 			  ldap_db_t *ldap_db, dns_name_t *name,
@@ -143,47 +147,47 @@ cached_ldap_rdatalist_get(isc_mem_t *mctx, ldap_cache_t *cache,
 	isc_result_t result;
 	ldapdb_rdatalist_t rdlist;
 	cache_node_t *node = NULL;
-	void *data = NULL;
-	int found = 0;
-	int expired = 0;
+	int in_cache = 0;
 
 	REQUIRE(cache != NULL);
 
-	INIT_LIST(*rdatalist);
-	INIT_LIST(rdlist);
-
 	if (cache->rbt == NULL)
 		return ldapdb_rdatalist_get(mctx, ldap_db, name, rdatalist);
 
-	result = dns_rbt_findname(cache->rbt, name, 0, NULL, &data);
+	result = dns_rbt_findname(cache->rbt, name, 0, NULL, (void *)&node);
 	if (result == ISC_R_SUCCESS) {
-		found = 1;
-		expired = 0; /* find out if we are expired */
-		node = (cache_node_t *)data;
-		rdlist = node->rdatalist;
+		isc_time_t now;
+
+		CHECK(isc_time_now(&now));
+
+		/* Check if the record is still valid. */
+		if (isc_time_compare(&now, &node->valid_until) > 0) {
+			CHECK(dns_rbt_deletename(cache->rbt, name, ISC_FALSE));
+			node = NULL;
+			in_cache = 0;
+		} else {
+			rdlist = node->rdatalist;
+			in_cache = 1;
+		}
 	} else if (result != ISC_R_NOTFOUND && result != DNS_R_PARTIALMATCH) {
 		goto cleanup;
+	} else {
+		node = NULL;
 	}
 
-	if ((found && expired) || !found) {
-		if (found) {
-			CHECK(dns_rbt_deletename(cache->rbt, name, ISC_FALSE));
-			data = NULL; /* ? */
-		}
+	if (!in_cache) {
 		INIT_LIST(rdlist);
 		result = ldapdb_rdatalist_get(mctx, ldap_db, name, &rdlist);
 		if (result != ISC_R_SUCCESS && result != ISC_R_NOTFOUND)
 			goto cleanup;
-		CHECK(cache_node_create(mctx, rdlist, &node));
-		data = (void *)node;
-		CHECK(dns_rbt_addname(cache->rbt, name, data));
+		CHECK(cache_node_create(cache, rdlist, &node));
+		CHECK(dns_rbt_addname(cache->rbt, name, (void *)node));
 	}
+
 	CHECK(ldap_rdatalist_copy(mctx, rdlist, rdatalist));
 
 	if (EMPTY(*rdatalist))
-		return ISC_R_NOTFOUND;
-	else
-		return ISC_R_SUCCESS;
+		result = ISC_R_NOTFOUND;
 
 cleanup:
 	return result;