Redis TTL

cachedb/cachedb.c

@@ -160,7 +160,7 @@ testframe_lookup(struct module_env* env, struct cachedb_env* cachedb_env,
 
 static void
 testframe_store(struct module_env* env, struct cachedb_env* cachedb_env,
-	char* key, uint8_t* data, size_t data_len)
+	char* key, uint8_t* data, size_t data_len, time_t ATTR_UNUSED(ttl))
 {
 	struct testframe_moddata* d = (struct testframe_moddata*)
 		cachedb_env->backend_data;
@@ -606,7 +606,8 @@ cachedb_extcache_store(struct module_qstate* qstate, struct cachedb_env* ie)
 	/* call backend */
 	(*ie->backend->store)(qstate->env, ie, key,
 		sldns_buffer_begin(qstate->env->scratch_buffer),
-		sldns_buffer_limit(qstate->env->scratch_buffer));
+		sldns_buffer_limit(qstate->env->scratch_buffer),
+		qstate->return_msg->rep->ttl);
 }
 
 /**

cachedb/cachedb.h

@@ -84,7 +84,7 @@ struct cachedb_backend {
 
 	/** Store (env, cachedb_env, key, data, data_len) */
 	void (*store)(struct module_env*, struct cachedb_env*, char*,
-		uint8_t*, size_t);
+		uint8_t*, size_t, time_t);
 };
 
 #define CACHEDB_HASHSIZE 256 /* bit hash */

cachedb/redis.c

@@ -59,6 +59,9 @@ struct redis_moddata {
 	struct timeval timeout;	 /* timeout for connection setup and commands */
 };
 
+static redisReply* redis_command(struct module_env*, struct cachedb_env*,
+	const char*, const uint8_t*, size_t);
+
 static redisContext*
 redis_connect(const struct redis_moddata* moddata)
 {
@@ -90,6 +93,8 @@ redis_init(struct module_env* env, struct cachedb_env* cachedb_env)
 {
 	int i;
 	struct redis_moddata* moddata = NULL;
+	redisReply* rep;
+	int redis_reply_type = 0;
 
 	verbose(VERB_ALGO, "redis_init");
 
@@ -114,6 +119,26 @@ redis_init(struct module_env* env, struct cachedb_env* cachedb_env)
 	for(i = 0; i < moddata->numctxs; i++)
 		moddata->ctxs[i] = redis_connect(moddata);
 	cachedb_env->backend_data = moddata;
+	if (env->cfg->redis_expire_records) {
+		/** check if setex command is supported */
+		rep = redis_command(env, cachedb_env, "SETEX __UNBOUND_REDIS_CHECK__ 1 none", NULL, 0);
+		if(!rep) {
+			/** init failed, no response from redis server*/
+			log_err("redis_init: failed to init redis, the redis-expire-records option requires the SETEX command (redis >= 2.0.0)");
+			return 0;
+		}
+		redis_reply_type = rep->type;
+		freeReplyObject(rep);
+		switch (redis_reply_type) {
+		case REDIS_REPLY_STATUS:
+			break;
+		default:
+			/** init failed, setex command not supported */
+			log_err("redis_init: failed to init redis, the redis-expire-records option requires the SETEX command (redis >= 2.0.0)");
+			return 0;
+		}
+	}
+
 	return 1;
 }
 
@@ -249,16 +274,26 @@ redis_lookup(struct module_env* env, struct cachedb_env* cachedb_env,
 
 static void
 redis_store(struct module_env* env, struct cachedb_env* cachedb_env,
-	char* key, uint8_t* data, size_t data_len)
+	char* key, uint8_t* data, size_t data_len, time_t ttl)
 {
 	redisReply* rep;
-	char cmdbuf[4+(CACHEDB_HASHSIZE/8)*2+3+1]; /* "SET " + key + " %b" */
 	int n;
+	int set_ttl = (int)(env->cfg->redis_expire_records && (!env->cfg->serve_expired || env->cfg->serve_expired_ttl > 0));
+	char cmdbuf[6+(CACHEDB_HASHSIZE/8)*2+11+3+1]; /* "SETEX " + key + " " + ttl + " %b" or "SET " + key + " %b"*/ 
+
+	if (!set_ttl) {
+		verbose(VERB_ALGO, "redis_store %s (%d bytes)", key, (int)data_len);
+		/* build command to set to a binary safe string */
+		n = snprintf(cmdbuf, sizeof(cmdbuf), "SET %s %%b", key);
+	} else {
+		/* add expired ttl time to redis ttl to avoid premature eviction of key */
+		ttl += env->cfg->serve_expired_ttl;
+		verbose(VERB_ALGO, "redis_store %s (%d bytes) with ttl %u", key, (int)data_len, (uint32_t)ttl);
+		/* build command to set to a binary safe string */
+		n = snprintf(cmdbuf, sizeof(cmdbuf), "SETEX %s %u %%b", key, (uint32_t)ttl);
+	}
 
-	verbose(VERB_ALGO, "redis_store %s (%d bytes)", key, (int)data_len);
 
-	/* build command to set to a binary safe string */
-	n = snprintf(cmdbuf, sizeof(cmdbuf), "SET %s %%b", key);
 	if(n < 0 || n >= (int)sizeof(cmdbuf)) {
 		log_err("redis_store: unexpected failure to build command");
 		return;

doc/unbound.conf.5.in

@@ -2127,6 +2127,14 @@ If this timeout expires Unbound closes the connection, treats it as
 if the Redis server does not have the requested data, and will try to
 re-establish a new connection later.
 This option defaults to 100 milliseconds.
+.TP
+.B redis-expire-records: \fI<yes or no>
+If redis record expiration is enabled. If yes, unbound sets ttl for redis 
+records so that redis can evict keys that have expired automatically. If 
+unbound is configured to serve expired entries and there is no expired ttl 
+set, this option is internally reverted to "no". Redis SETEX support required
+(redis >= 2.0.0).
+This option defaults to no.
 .SS DNSTAP Logging Options
 DNSTAP support, when compiled in, is enabled in the \fBdnstap:\fR section.
 This starts an extra thread (when compiled with threading) that writes

util/config_file.c

@@ -337,6 +337,7 @@ config_create(void)
 	if(!(cfg->redis_server_host = strdup("127.0.0.1"))) goto error_exit;
 	cfg->redis_timeout = 100;
 	cfg->redis_server_port = 6379;
+	cfg->redis_expire_records = 0;
 #endif  /* USE_REDIS */
 #endif  /* USE_CACHEDB */
 #ifdef USE_IPSET
@@ -1135,6 +1136,7 @@ config_get_option(struct config_file* cfg, const char* opt,
 	else O_STR(opt, "redis-server-host", redis_server_host)
 	else O_DEC(opt, "redis-server-port", redis_server_port)
 	else O_DEC(opt, "redis-timeout", redis_timeout)
+	else O_YNO(opt, "redis-expire-records", redis_expire_records)
 #endif  /* USE_REDIS */
 #endif  /* USE_CACHEDB */
 #ifdef USE_IPSET

util/config_file.h

@@ -598,6 +598,8 @@ struct config_file {
 	int redis_server_port;
 	/** timeout (in ms) for communication with the redis server */
 	int redis_timeout;
+	/** set redis ttl value based on dns response ttl */
+	int redis_expire_records;
 #endif
 #endif