Bridge support for MQTT v5 maximum-qos.

ChangeLog.txt

@@ -97,6 +97,7 @@ Broker:
 - Fix bridges incorrectly setting Wills to manage remote notifications when
   `notifications_local_only` was set true. Closes #1902.
 - Bridges now obey MQTT v5 server-keepalive.
+- Add bridge support for the MQTT v5 maximum-qos property.
 
 Client library:
 - Client no longer generates random client ids for v3.1.1 clients, these are

lib/actions.c

@@ -49,7 +49,7 @@ int mosquitto_publish_v5(struct mosquitto *mosq, int *mid, const char *topic, in
 
 	if(!mosq || qos<0 || qos>2) return MOSQ_ERR_INVAL;
 	if(mosq->protocol != mosq_p_mqtt5 && properties) return MOSQ_ERR_NOT_SUPPORTED;
-	if(qos > mosq->maximum_qos) return MOSQ_ERR_QOS_NOT_SUPPORTED;
+	if(qos > mosq->max_qos) return MOSQ_ERR_QOS_NOT_SUPPORTED;
 
 	if(!mosq->retain_available){
 		retain = false;

lib/handle_connack.c

@@ -98,7 +98,7 @@ int handle__connack(struct mosquitto *mosq)
 	}
 
 	mosquitto_property_read_byte(properties, MQTT_PROP_RETAIN_AVAILABLE, &mosq->retain_available, false);
-	mosquitto_property_read_byte(properties, MQTT_PROP_MAXIMUM_QOS, &mosq->maximum_qos, false);
+	mosquitto_property_read_byte(properties, MQTT_PROP_MAXIMUM_QOS, &mosq->max_qos, false);
 	mosquitto_property_read_int16(properties, MQTT_PROP_RECEIVE_MAXIMUM, &mosq->msgs_out.inflight_maximum, false);
 	mosquitto_property_read_int16(properties, MQTT_PROP_SERVER_KEEP_ALIVE, &mosq->keepalive, false);
 	mosquitto_property_read_int32(properties, MQTT_PROP_MAXIMUM_PACKET_SIZE, &mosq->maximum_packet_size, false);

lib/mosquitto.c

@@ -173,7 +173,7 @@ int mosquitto_reinitialise(struct mosquitto *mosq, const char *id, bool clean_st
 	mosq->ping_t = 0;
 	mosq->last_mid = 0;
 	mosq->state = mosq_cs_new;
-	mosq->maximum_qos = 2;
+	mosq->max_qos = 2;
 	mosq->msgs_in.inflight_maximum = 20;
 	mosq->msgs_out.inflight_maximum = 20;
 	mosq->msgs_in.inflight_quota = 20;

lib/mosquitto_internal.h

@@ -335,7 +335,7 @@ struct mosquitto {
 	ares_channel achan;
 #  endif
 #endif
-	uint8_t maximum_qos;
+	uint8_t max_qos;
 	uint8_t retain_available;
 	bool tcp_nodelay;
 

man/mosquitto.conf.5.xml

@@ -1107,7 +1107,7 @@ log_timestamp_format %Y-%m-%dT%H:%M:%S
 					</listitem>
 				</varlistentry>
 				<varlistentry>
-					<term><option>maximum_qos</option> <replaceable>count</replaceable></term>
+					<term><option>max_qos</option> <replaceable>value</replaceable></term>
 					<listitem>
 						<para>Limit the QoS value allowed for clients connecting to this
 							listener. Defaults to 2, which means any QoS can be

mosquitto.conf

@@ -97,6 +97,10 @@
 # be queued until the first limit is reached.
 #max_queued_bytes 0
 
+# Set the maximum QoS supported. Clients publishing at a QoS higher than
+# specified here will be disconnected.
+#max_qos 2
+
 # The maximum number of QoS 1 and 2 messages to hold in a queue per client
 # above those that are currently in-flight.  Defaults to 1000. Set
 # to 0 for no maximum (not recommended).

src/bridge.c

@@ -149,6 +149,7 @@ int bridge__connect_step1(struct mosquitto *context)
 	size_t notification_topic_len;
 	uint8_t notification_payload;
 	int i;
+	uint8_t qos;
 
 	if(!context || !context->bridge) return MOSQ_ERR_INVAL;
 
@@ -176,9 +177,14 @@ int bridge__connect_step1(struct mosquitto *context)
 	for(i=0; i<context->bridge->topic_count; i++){
 		if(context->bridge->topics[i].direction == bd_out || context->bridge->topics[i].direction == bd_both){
 			log__printf(NULL, MOSQ_LOG_DEBUG, "Bridge %s doing local SUBSCRIBE on topic %s", context->id, context->bridge->topics[i].local_topic);
+			if(context->bridge->topics[i].qos > context->max_qos){
+				qos = context->max_qos;
+			}else{
+				qos = context->bridge->topics[i].qos;
+			}
 			if(sub__add(context,
 						context->bridge->topics[i].local_topic,
-						context->bridge->topics[i].qos,
+						qos,
 						0,
 						MQTT_SUB_OPT_NO_LOCAL | MQTT_SUB_OPT_RETAIN_AS_PUBLISHED,
 						&db.subs) > 0){
@@ -186,7 +192,7 @@ int bridge__connect_step1(struct mosquitto *context)
 			}
 			retain__queue(context,
 					context->bridge->topics[i].local_topic,
-					context->bridge->topics[i].qos, 0);
+					qos, 0);
 		}
 	}
 
@@ -194,14 +200,19 @@ int bridge__connect_step1(struct mosquitto *context)
 	bridge__backoff_step(context);
 
 	if(context->bridge->notifications){
+		if(context->max_qos == 0){
+			qos = 0;
+		}else{
+			qos = 1;
+		}
 		if(context->bridge->notification_topic){
 			if(!context->bridge->initial_notification_done){
 				notification_payload = '0';
-				db__messages_easy_queue(context, context->bridge->notification_topic, 1, 1, &notification_payload, 1, 0, NULL);
+				db__messages_easy_queue(context, context->bridge->notification_topic, qos, 1, &notification_payload, 1, 0, NULL);
 				context->bridge->initial_notification_done = true;
 			}
 			notification_payload = '0';
-			rc = will__set(context, context->bridge->notification_topic, 1, &notification_payload, 1, true, NULL);
+			rc = will__set(context, context->bridge->notification_topic, 1, &notification_payload, qos, true, NULL);
 			if(rc != MOSQ_ERR_SUCCESS){
 				return rc;
 			}
@@ -214,12 +225,12 @@ int bridge__connect_step1(struct mosquitto *context)
 
 			if(!context->bridge->initial_notification_done){
 				notification_payload = '0';
-				db__messages_easy_queue(context, notification_topic, 1, 1, &notification_payload, 1, 0, NULL);
+				db__messages_easy_queue(context, notification_topic, qos, 1, &notification_payload, 1, 0, NULL);
 				context->bridge->initial_notification_done = true;
 			}
 
 			notification_payload = '0';
-			rc = will__set(context, notification_topic, 1, &notification_payload, 1, true, NULL);
+			rc = will__set(context, notification_topic, 1, &notification_payload, qos, true, NULL);
 			mosquitto__free(notification_topic);
 			if(rc != MOSQ_ERR_SUCCESS){
 				return rc;
@@ -326,6 +337,7 @@ int bridge__connect(struct mosquitto *context)
 	char *notification_topic = NULL;
 	size_t notification_topic_len;
 	uint8_t notification_payload;
+	uint8_t qos;
 
 	if(!context || !context->bridge) return MOSQ_ERR_INVAL;
 
@@ -353,9 +365,14 @@ int bridge__connect(struct mosquitto *context)
 	for(i=0; i<context->bridge->topic_count; i++){
 		if(context->bridge->topics[i].direction == bd_out || context->bridge->topics[i].direction == bd_both){
 			log__printf(NULL, MOSQ_LOG_DEBUG, "Bridge %s doing local SUBSCRIBE on topic %s", context->id, context->bridge->topics[i].local_topic);
+			if(context->bridge->topics[i].qos > context->max_qos){
+				qos = context->max_qos;
+			}else{
+				qos = context->bridge->topics[i].qos;
+			}
 			if(sub__add(context,
 						context->bridge->topics[i].local_topic,
-						context->bridge->topics[i].qos,
+						qos,
 						0,
 						MQTT_SUB_OPT_NO_LOCAL | MQTT_SUB_OPT_RETAIN_AS_PUBLISHED,
 						&db.subs) > 0){
@@ -369,15 +386,20 @@ int bridge__connect(struct mosquitto *context)
 	bridge__backoff_step(context);
 
 	if(context->bridge->notifications){
+		if(context->max_qos == 0){
+			qos = 0;
+		}else{
+			qos = 1;
+		}
 		if(context->bridge->notification_topic){
 			if(!context->bridge->initial_notification_done){
 				notification_payload = '0';
-				db__messages_easy_queue(context, context->bridge->notification_topic, 1, 1, &notification_payload, 1, 0, NULL);
+				db__messages_easy_queue(context, context->bridge->notification_topic, qos, 1, &notification_payload, 1, 0, NULL);
 				context->bridge->initial_notification_done = true;
 			}
 
 			notification_payload = '0';
-			rc = will__set(context, context->bridge->notification_topic, 1, &notification_payload, 1, true, NULL);
+			rc = will__set(context, context->bridge->notification_topic, 1, &notification_payload, qos, true, NULL);
 			if(rc != MOSQ_ERR_SUCCESS){
 				return rc;
 			}
@@ -390,12 +412,12 @@ int bridge__connect(struct mosquitto *context)
 
 			if(!context->bridge->initial_notification_done){
 				notification_payload = '0';
-				db__messages_easy_queue(context, notification_topic, 1, 1, &notification_payload, 1, 0, NULL);
+				db__messages_easy_queue(context, notification_topic, qos, 1, &notification_payload, 1, 0, NULL);
 				context->bridge->initial_notification_done = true;
 			}
 
 			notification_payload = '0';
-			rc = will__set(context, notification_topic, 1, &notification_payload, 1, true, NULL);
+			rc = will__set(context, notification_topic, 1, &notification_payload, qos, true, NULL);
 			if(rc != MOSQ_ERR_SUCCESS){
 				mosquitto__free(notification_topic);
 				return rc;
@@ -459,8 +481,14 @@ int bridge__on_connect(struct mosquitto *context)
 	char notification_payload;
 	int sub_opts;
 	bool retain = true;
+	uint8_t qos;
 
 	if(context->bridge->notifications){
+		if(context->max_qos == 0){
+			qos = 0;
+		}else{
+			qos = 1;
+		}
 		if(!context->retain_available){
 			retain = false;
 		}
@@ -468,12 +496,12 @@ int bridge__on_connect(struct mosquitto *context)
 		if(context->bridge->notification_topic){
 			if(!context->bridge->notifications_local_only){
 				if(send__real_publish(context, mosquitto__mid_generate(context),
-						context->bridge->notification_topic, 1, &notification_payload, 1, retain, 0, NULL, NULL, 0)){
+						context->bridge->notification_topic, 1, &notification_payload, qos, retain, 0, NULL, NULL, 0)){
 
 					return 1;
 				}
 			}
-			db__messages_easy_queue(context, context->bridge->notification_topic, 1, 1, &notification_payload, 1, 0, NULL);
+			db__messages_easy_queue(context, context->bridge->notification_topic, qos, 1, &notification_payload, 1, 0, NULL);
 		}else{
 			notification_topic_len = strlen(context->bridge->remote_clientid)+strlen("$SYS/broker/connection//state");
 			notification_topic = mosquitto__malloc(sizeof(char)*(notification_topic_len+1));
@@ -483,19 +511,23 @@ int bridge__on_connect(struct mosquitto *context)
 			notification_payload = '1';
 			if(!context->bridge->notifications_local_only){
 				if(send__real_publish(context, mosquitto__mid_generate(context),
-						notification_topic, 1, &notification_payload, 1, retain, 0, NULL, NULL, 0)){
+						notification_topic, 1, &notification_payload, qos, retain, 0, NULL, NULL, 0)){
 
 					mosquitto__free(notification_topic);
 					return 1;
 				}
 			}
-			db__messages_easy_queue(context, notification_topic, 1, 1, &notification_payload, 1, 0, NULL);
+			db__messages_easy_queue(context, notification_topic, qos, 1, &notification_payload, 1, 0, NULL);
 			mosquitto__free(notification_topic);
 		}
 	}
 	for(i=0; i<context->bridge->topic_count; i++){
 		if(context->bridge->topics[i].direction == bd_in || context->bridge->topics[i].direction == bd_both){
-			sub_opts = context->bridge->topics[i].qos;
+			if(context->bridge->topics[i].qos > context->max_qos){
+				sub_opts = context->max_qos;
+			}else{
+				sub_opts = context->bridge->topics[i].qos;
+			}
 			if(context->bridge->protocol_version == mosq_p_mqtt5){
 				sub_opts = sub_opts
 					| MQTT_SUB_OPT_NO_LOCAL
@@ -518,9 +550,14 @@ int bridge__on_connect(struct mosquitto *context)
 	}
 	for(i=0; i<context->bridge->topic_count; i++){
 		if(context->bridge->topics[i].direction == bd_out || context->bridge->topics[i].direction == bd_both){
+			if(context->bridge->topics[i].qos > context->max_qos){
+				qos = context->max_qos;
+			}else{
+				qos = context->bridge->topics[i].qos;
+			}
 			retain__queue(context,
 					context->bridge->topics[i].local_topic,
-					context->bridge->topics[i].qos, 0);
+					qos, 0);
 		}
 	}
 

src/conf.c

@@ -441,7 +441,7 @@ int config__parse_args(struct mosquitto__config *config, int argc, char *argv[])
 			|| config->default_listener.host
 			|| config->default_listener.port
 			|| config->default_listener.max_connections != -1
-			|| config->default_listener.maximum_qos != 2
+			|| config->default_listener.max_qos != 2
 			|| config->default_listener.mount_point
 			|| config->default_listener.protocol != mp_mqtt
 			|| config->default_listener.socket_domain
@@ -482,7 +482,7 @@ int config__parse_args(struct mosquitto__config *config, int argc, char *argv[])
 		config->listeners[config->listener_count-1].sock_count = 0;
 		config->listeners[config->listener_count-1].client_count = 0;
 		config->listeners[config->listener_count-1].use_username_as_clientid = config->default_listener.use_username_as_clientid;
-		config->listeners[config->listener_count-1].maximum_qos = config->default_listener.maximum_qos;
+		config->listeners[config->listener_count-1].max_qos = config->default_listener.max_qos;
 		config->listeners[config->listener_count-1].max_topic_alias = config->default_listener.max_topic_alias;
 #ifdef WITH_TLS
 		config->listeners[config->listener_count-1].tls_version = config->default_listener.tls_version;
@@ -1625,14 +1625,14 @@ int config__read_file_core(struct mosquitto__config *config, bool reload, struct
 					}else{
 						log__printf(NULL, MOSQ_LOG_ERR, "Error: Empty max_connections value in configuration.");
 					}
-				}else if(!strcmp(token, "maximum_qos")){
+				}else if(!strcmp(token, "maximum_qos") || !strcmp(token, "max_qos")){
 					if(reload) continue; /* Listeners not valid for reloading. */
-					if(conf__parse_int(&token, "maximum_qos", &tmp_int, saveptr)) return MOSQ_ERR_INVAL;
+					if(conf__parse_int(&token, token, &tmp_int, saveptr)) return MOSQ_ERR_INVAL;
 					if(tmp_int < 0 || tmp_int > 2){
-						log__printf(NULL, MOSQ_LOG_ERR, "Error: maximum_qos must be between 0 and 2 inclusive.");
+						log__printf(NULL, MOSQ_LOG_ERR, "Error: max_qos must be between 0 and 2 inclusive.");
 						return MOSQ_ERR_INVAL;
 					}
-					cur_listener->maximum_qos = (uint8_t)tmp_int;
+					cur_listener->max_qos = (uint8_t)tmp_int;
 				}else if(!strcmp(token, "max_inflight_bytes")){
 					if(conf__parse_int(&token, "max_inflight_bytes", &tmp_int, saveptr)) return MOSQ_ERR_INVAL;
 					if(tmp_int < 0) tmp_int = 0;

src/context.c

@@ -83,7 +83,7 @@ struct mosquitto *context__init(mosq_sock_t sock)
 	context->msgs_out.inflight_maximum = db.config->max_inflight_messages;
 	context->msgs_in.inflight_quota = db.config->max_inflight_messages;
 	context->msgs_out.inflight_quota = db.config->max_inflight_messages;
-	context->maximum_qos = 2;
+	context->max_qos = 2;
 #ifdef WITH_TLS
 	context->ssl = NULL;
 #endif

src/database.c

@@ -492,8 +492,8 @@ int db__message_insert(struct mosquitto *context, uint16_t mid, enum mosquitto_m
 	msg->direction = dir;
 	msg->state = state;
 	msg->dup = false;
-	if(qos > context->maximum_qos){
-		msg->qos = context->maximum_qos;
+	if(qos > context->max_qos){
+		msg->qos = context->max_qos;
 	}else{
 		msg->qos = qos;
 	}

src/handle_connack.c

@@ -35,6 +35,7 @@ int handle__connack(struct mosquitto *context)
 	uint32_t maximum_packet_size;
 	uint8_t retain_available;
 	uint16_t server_keepalive;
+	uint8_t max_qos = 255;
 
 	if(!context){
 		return MOSQ_ERR_INVAL;
@@ -56,9 +57,14 @@ int handle__connack(struct mosquitto *context)
 			context->bridge->protocol_version = mosq_p_mqtt311;
 			return MOSQ_ERR_PROTOCOL;
 		}
+
 		rc = property__read_all(CMD_CONNACK, &context->in_packet, &properties);
 		if(rc) return rc;
 
+		/* maximum-qos */
+		mosquitto_property_read_byte(properties, MQTT_PROP_MAXIMUM_QOS,
+					&max_qos, false);
+
 		/* maximum-packet-size */
 		if(mosquitto_property_read_int32(properties, MQTT_PROP_MAXIMUM_PACKET_SIZE,
 					&maximum_packet_size, false)){
@@ -96,6 +102,9 @@ int handle__connack(struct mosquitto *context)
 			if(rc) return rc;
 		}
 #endif
+		if(max_qos != 255){
+			context->max_qos = max_qos;
+		}
 		mosquitto__set_state(context, mosq_cs_active);
 		rc = db__message_write_queued_out(context);
 		if(rc) return rc;
@@ -108,6 +117,16 @@ int handle__connack(struct mosquitto *context)
 					context->retain_available = 0;
 					log__printf(NULL, MOSQ_LOG_ERR, "Connection Refused: retain not available (will retry)");
 					return MOSQ_ERR_CONN_LOST;
+				case MQTT_RC_QOS_NOT_SUPPORTED:
+					if(max_qos == 255){
+						if(context->max_qos != 0){
+							context->max_qos--;
+						}
+					}else{
+						context->max_qos = max_qos;
+					}
+					log__printf(NULL, MOSQ_LOG_ERR, "Connection Refused: QoS not supported (will retry)");
+					return MOSQ_ERR_CONN_LOST;
 				default:
 					log__printf(NULL, MOSQ_LOG_ERR, "Connection Refused: %s", mosquitto_reason_string(reason_code));
 					return MOSQ_ERR_CONN_LOST;

src/handle_connect.c

@@ -225,7 +225,7 @@ int connect__on_authorised(struct mosquitto *context, void *auth_data_out, uint1
 		db.persistence_changes++;
 	}
 #endif
-	context->maximum_qos = context->listener->maximum_qos;
+	context->max_qos = context->listener->max_qos;
 
 	if(context->protocol == mosq_p_mqtt5){
 		if(context->listener->max_topic_alias > 0){
@@ -234,12 +234,6 @@ int connect__on_authorised(struct mosquitto *context, void *auth_data_out, uint1
 				goto error;
 			}
 		}
-		if(context->maximum_qos != 2){
-			if(mosquitto_property_add_byte(&connack_props, MQTT_PROP_MAXIMUM_QOS, context->maximum_qos)){
-				rc = MOSQ_ERR_NOMEM;
-				goto error;
-			}
-		}
 		if(context->keepalive > db.config->max_keepalive){
 			context->keepalive = db.config->max_keepalive;
 			if(mosquitto_property_add_int16(&connack_props, MQTT_PROP_SERVER_KEEP_ALIVE, context->keepalive)){
@@ -528,6 +522,14 @@ int handle__connect(struct mosquitto *context)
 	}
 	property__process_connect(context, &properties);
 
+	if(will && will_qos > context->listener->max_qos){
+		if(protocol_version == mosq_p_mqtt5){
+			send__connack(context, 0, MQTT_RC_QOS_NOT_SUPPORTED, NULL);
+		}
+		rc = MOSQ_ERR_NOT_SUPPORTED;
+		goto handle_connect_error;
+	}
+
 	if(mosquitto_property_read_string(properties, MQTT_PROP_AUTHENTICATION_METHOD, &context->auth_method, false)){
 		mosquitto_property_read_binary(properties, MQTT_PROP_AUTHENTICATION_DATA, &auth_data, &auth_data_len, false);
 	}

src/handle_publish.c

@@ -68,7 +68,7 @@ int handle__publish(struct mosquitto *context)
 		db__msg_store_free(msg);
 		return MOSQ_ERR_MALFORMED_PACKET;
 	}
-	if(msg->qos > context->maximum_qos){
+	if(msg->qos > context->max_qos){
 		log__printf(NULL, MOSQ_LOG_INFO,
 				"Too high QoS in PUBLISH from %s, disconnecting.", context->id);
 		db__msg_store_free(msg);

src/handle_subscribe.c

@@ -142,6 +142,9 @@ int handle__subscribe(struct mosquitto *context)
 				mosquitto__free(payload);
 				return MOSQ_ERR_MALFORMED_PACKET;
 			}
+			if(qos > context->max_qos){
+				qos = context->max_qos;
+			}
 
 
 			if(context->listener && context->listener->mount_point){

src/loop.c

@@ -314,6 +314,9 @@ void do_disconnect(struct mosquitto *context, int reason)
 					case MOSQ_ERR_NOMEM:
 						log__printf(NULL, MOSQ_LOG_NOTICE, "Client %s disconnected due to out of memory.", id);
 						break;
+					case MOSQ_ERR_NOT_SUPPORTED:
+						log__printf(NULL, MOSQ_LOG_NOTICE, "Client %s disconnected due to QoS too high or retain not supported.", id);
+						break;
 					case MOSQ_ERR_ADMINISTRATIVE_ACTION:
 						log__printf(NULL, MOSQ_LOG_NOTICE, "Client %s been disconnected by administrative action.", id);
 						break;

src/mosquitto.c

@@ -174,7 +174,7 @@ void listener__set_defaults(struct mosquitto__listener *listener)
 	listener->security_options.allow_zero_length_clientid = true;
 	listener->protocol = mp_mqtt;
 	listener->max_connections = -1;
-	listener->maximum_qos = 2;
+	listener->max_qos = 2;
 	listener->max_topic_alias = 10;
 }
 

src/mosquitto_broker_internal.h

@@ -199,7 +199,7 @@ struct mosquitto__listener {
 	enum mosquitto_protocol protocol;
 	int socket_domain;
 	bool use_username_as_clientid;
-	uint8_t maximum_qos;
+	uint8_t max_qos;
 	uint16_t max_topic_alias;
 #ifdef WITH_TLS
 	char *cafile;
@@ -273,6 +273,7 @@ struct mosquitto__config {
 	uint32_t message_size_limit;
 	uint16_t max_inflight_messages;
 	uint16_t max_keepalive;
+	uint8_t max_qos;
 	bool persistence;
 	char *persistence_location;
 	char *persistence_file;

src/send_connack.c

@@ -65,6 +65,13 @@ int send__connack(struct mosquitto *context, uint8_t ack, uint8_t reason_code, c
 				return rc;
 			}
 		}
+		if(context->listener->max_qos != 2){
+			rc = mosquitto_property_add_byte(&connack_props, MQTT_PROP_MAXIMUM_QOS, context->listener->max_qos);
+			if(rc){
+				mosquitto_property_free_all(&connack_props);
+				return rc;
+			}
+		}
 
 		remaining_length += property__get_remaining_length(connack_props);
 	}

test/broker/13-malformed-publish-v5.py

@@ -22,9 +22,12 @@ def do_test(publish_packet, reason_code, error_string):
     keepalive = 10
     connect_packet = mosq_test.gen_connect("test", proto_ver=5, keepalive=keepalive)
 
-    connack_props = mqtt5_props.gen_byte_prop(mqtt5_props.PROP_MAXIMUM_QOS, 1)
+    connack_props = mqtt5_props.gen_uint16_prop(mqtt5_props.PROP_TOPIC_ALIAS_MAXIMUM, 10)
     connack_props += mqtt5_props.gen_byte_prop(mqtt5_props.PROP_RETAIN_AVAILABLE, 0)
-    connack_packet = mosq_test.gen_connack(rc=0, proto_ver=5, properties=connack_props)
+    connack_props += mqtt5_props.gen_uint16_prop(mqtt5_props.PROP_RECEIVE_MAXIMUM, 20)
+    connack_props += mqtt5_props.gen_byte_prop(mqtt5_props.PROP_MAXIMUM_QOS, 1)
+
+    connack_packet = mosq_test.gen_connack(rc=0, proto_ver=5, properties=connack_props, property_helper=False)
 
     mid = 0
     disconnect_packet = mosq_test.gen_disconnect(proto_ver=5, reason_code=reason_code)