Add retain_available support.

man/mosquitto.conf.5.xml

@@ -628,6 +628,16 @@
  <para>Reloaded on reload signal.</para>
  </listitem>
  </varlistentry>
+ <varlistentry>
+ <term><option>retain_available</option> [ true | false ]</term>
+ <listitem>
+ <para>If set to false, then retained messages are not
+ supported. Clients that send a message with the retain
+ bit will be disconnected if this option is set to
+ false. Defaults to true.</para>
+ <para>Reloaded on reload signal.</para>
+ </listitem>
+ </varlistentry>
  <varlistentry>
  <term><option>retained_persistence</option> [ true | false ]</term>
  <listitem>

mosquitto.conf

@@ -149,6 +149,12 @@
 #per_listener_settings false
 
 
+# Set to false to disable retained message support. If a client publishes a
+# message with the retain bit set, it will be disconnected if this is set to
+# false.
+#retain_available true
+
+
 # =================================================================
 # Default listener
 # =================================================================

src/conf.c

@@ -219,6 +219,7 @@ static void config__init_reload(struct mosquitto_db *db, struct mosquitto__confi
  config->persistence_file = NULL;
  config->persistent_client_expiration = 0;
  config->queue_qos0_messages = false;
+ config->retain_available = true;
  config->set_tcp_nodelay = false;
  config->sys_interval = 10;
  config->upgrade_outgoing_qos = false;
@@ -1729,6 +1730,8 @@ int config__read_file_core(struct mosquitto__config *config, bool reload, struct
 #else
  log__printf(NULL, MOSQ_LOG_WARNING, "Warning: Bridge support not available.");
 #endif
+ }else if(!strcmp(token, "retain_available")){
+ if(conf__parse_bool(&token, token, &config->retain_available, saveptr)) return MOSQ_ERR_INVAL;
  }else if(!strcmp(token, "retry_interval")){
  log__printf(NULL, MOSQ_LOG_WARNING, "Warning: The retry_interval option is no longer available.");
  }else if(!strcmp(token, "round_robin")){

src/database.c

@@ -575,6 +575,10 @@ int db__messages_easy_queue(struct mosquitto_db *db, struct mosquitto *context,
  topic_heap = mosquitto__strdup(topic);
  if(!topic_heap) return MOSQ_ERR_INVAL;
 
+ if(db->config->retain_available == false){
+ retain = 0;
+ }
+
  if(UHPA_ALLOC(payload_uhpa, payloadlen) == 0){
  mosquitto__free(topic_heap);
  return MOSQ_ERR_NOMEM;

src/handle_connect.c

@@ -236,6 +236,14 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
  password_flag = connect_flags & 0x40;
  username_flag = connect_flags & 0x80;
 
+ if(will && will_retain && db->config->retain_available == false){
+ if(protocol_version == mosq_p_mqtt5){
+ send__connack(db, context, 0, MQTT_RC_RETAIN_NOT_SUPPORTED);
+ }
+ rc = 1;
+ goto handle_connect_error;
+ }
+
  if(packet__read_uint16(&context->in_packet, &(context->keepalive))){
  rc = 1;
  goto handle_connect_error;

src/handle_publish.c

@@ -68,6 +68,13 @@ int handle__publish(struct mosquitto_db *db, struct mosquitto *context)
  }
  retain = (header & 0x01);
 
+ if(retain && db->config->retain_available == false){
+ if(context->protocol == mosq_p_mqtt5){
+ send__disconnect(context, MQTT_RC_RETAIN_NOT_SUPPORTED, NULL);
+ }
+ return 1;
+ }
+
  if(packet__read_string(&context->in_packet, &topic, &slen)) return 1;
  if(!slen){
  /* Invalid publish topic, disconnect client. */

src/mosquitto_broker_internal.h

@@ -268,6 +268,7 @@ struct mosquitto__config {
  char *pid_file;
  bool queue_qos0_messages;
  bool per_listener_settings;
+ bool retain_available;
  bool set_tcp_nodelay;
  int sys_interval;
  bool upgrade_outgoing_qos;

src/send_connack.c

@@ -44,6 +44,13 @@ int send__connack(struct mosquitto_db *db, struct mosquitto *context, int ack, i
  packet->command = CMD_CONNACK;
  packet->remaining_length = 2;
  if(context->protocol == mosq_p_mqtt5){
+ if(reason_code < 128 && db->config->retain_available == false){
+ rc = mosquitto_property_add_byte(&properties, MQTT_PROP_RETAIN_AVAILABLE, 0);
+ if(rc){
+ mosquitto__free(packet);
+ return rc;
+ }
+ }
  proplen = property__get_length_all(properties);
  varbytes = packet__varint_bytes(proplen);
  packet->remaining_length += proplen + varbytes;