Better outgoing QoS 0 limiting.

ChangeLog.txt

@@ -40,6 +40,8 @@ Breaking changes:
   regardless of whether the `-d` argument is used when running the broker.
 - The `tls_version` option now defines the *minimum* TLS protocol version to
   be used, rather than the exact version. Closes #1258.
+- The `max_queued_messages` option has been increased from 100 to 1000 by
+  default, and now also applies to QoS 0 messages, when a client is connected.
 
 Broker:
 - When running as root, if dropping privileges to the "mosquitto" user fails,

buildtest.py

@@ -22,6 +22,7 @@ build_variants = [
     'WITH_UNIX_SOCKETS',
     'WITH_WEBSOCKETS',
     'WITH_WRAP',
+    'WITH_XTREPORT',
 ]
 
 special_variants = [

lib/connect.c

@@ -267,7 +267,6 @@ void do_client_disconnect(struct mosquitto *mosq, int reason_code, const mosquit
 	mosq->current_out_packet = mosq->out_packet;
 	if(mosq->out_packet){
 		mosq->out_packet = mosq->out_packet->next;
-		mosq->out_packet_len--;
 		if(!mosq->out_packet){
 			mosq->out_packet_last = NULL;
 		}

lib/mosquitto_internal.h

@@ -233,7 +233,6 @@ struct mosquitto {
 	struct mosquitto_message_all *will;
 	struct mosquitto__alias *aliases;
 	struct will_delay_list *will_delay_entry;
-	int out_packet_len;
 	int alias_count;
 	uint32_t maximum_packet_size;
 	uint32_t will_delay_interval;

lib/packet_mosq.c

@@ -123,7 +123,6 @@ void packet__cleanup_all(struct mosquitto *mosq)
 		packet__cleanup(packet);
 		mosquitto__free(packet);
 	}
-	mosq->out_packet_len = 0;
 
 	packet__cleanup(&mosq->in_packet);
 
@@ -151,7 +150,6 @@ int packet__queue(struct mosquitto *mosq, struct mosquitto__packet *packet)
 		mosq->out_packet = packet;
 	}
 	mosq->out_packet_last = packet;
-	mosq->out_packet_len++;
 	pthread_mutex_unlock(&mosq->out_packet_mutex);
 #ifdef WITH_BROKER
 #  ifdef WITH_WEBSOCKETS
@@ -215,7 +213,6 @@ int packet__write(struct mosquitto *mosq)
 	if(mosq->out_packet && !mosq->current_out_packet){
 		mosq->current_out_packet = mosq->out_packet;
 		mosq->out_packet = mosq->out_packet->next;
-		mosq->out_packet_len--;
 		if(!mosq->out_packet){
 			mosq->out_packet_last = NULL;
 		}
@@ -297,7 +294,6 @@ int packet__write(struct mosquitto *mosq)
 		mosq->current_out_packet = mosq->out_packet;
 		if(mosq->out_packet){
 			mosq->out_packet = mosq->out_packet->next;
-			mosq->out_packet_len--;
 			if(!mosq->out_packet){
 				mosq->out_packet_last = NULL;
 			}

lib/send_publish.c

@@ -63,29 +63,6 @@ int send__publish(struct mosquitto *mosq, uint16_t mid, const char *topic, uint3
 	}
 
 #ifdef WITH_BROKER
-	if(qos == 0){
-		/* This is a crude, incorrect limit on the number of QoS 0 PUBLISHes.
-		 * We limit QoS 1 and 2 *messages* to max_inflight_messages+max_queued_messages.
-		 * We don't create QoS 0 *messages* though, only *packets*. So it is
-		 * tricky to add a correct limit on QoS 0 PUBLISHes.
-		 * This check will drop any further outgoing QoS PUBLISHes if the queue
-		 * of packets to be sent hits the max_queued_messages limit. It won't
-		 * be exactly correct, but does set an upper limit on queued QoS 0
-		 * packets.
-		 */
-		if(mosq->out_packet_len >= db.config->max_queued_messages){
-			return MOSQ_ERR_SUCCESS;
-		}
-	}
-	if(mosq->listener && mosq->listener->mount_point){
-		len = strlen(mosq->listener->mount_point);
-		if(len < strlen(topic)){
-			topic += len;
-		}else{
-			/* Invalid topic string. Should never happen, but silently swallow the message anyway. */
-			return MOSQ_ERR_SUCCESS;
-		}
-	}
 #ifdef WITH_BRIDGE
 	if(mosq->bridge && mosq->bridge->topics && mosq->bridge->topic_remapping){
 		for(i=0; i<mosq->bridge->topic_count; i++){

src/bridge.c

@@ -609,7 +609,6 @@ void bridge__packet_cleanup(struct mosquitto *context)
 	}
 	context->out_packet = NULL;
 	context->out_packet_last = NULL;
-	context->out_packet_len = 0;
 
 	packet__cleanup(&(context->in_packet));
 }

src/context.c

@@ -65,7 +65,6 @@ struct mosquitto *context__init(mosq_sock_t sock)
 	context->in_packet.payload = NULL;
 	packet__cleanup(&context->in_packet);
 	context->out_packet = NULL;
-	context->out_packet_len = 0;
 	context->current_out_packet = NULL;
 
 	context->address = NULL;
@@ -156,7 +155,6 @@ void context__cleanup(struct mosquitto *context, bool force_free)
 		context->out_packet = context->out_packet->next;
 		mosquitto__free(packet);
 	}
-	context->out_packet_len = 0;
 #if defined(WITH_BROKER) && defined(__GLIBC__) && defined(WITH_ADNS)
 	if(context->adns){
 		gai_cancel(context->adns);

src/database.c

@@ -38,10 +38,26 @@ bool db__ready_for_flight(struct mosquitto_msg_data *msgs, int qos)
 	bool valid_bytes;
 	bool valid_count;
 
-	if(qos == 0 || (msgs->inflight_maximum == 0 && db.config->max_inflight_bytes == 0)){
+	if(msgs->inflight_maximum == 0 && db.config->max_inflight_bytes == 0){
 		return true;
 	}
 
+	if(qos == 0){
+		/* Deliver QoS 0 messages unless the queue is already full.
+		 * For QoS 0 messages the choice is either "inflight" or dropped.
+		 * There is no queueing option, unless the client is offline and
+		 * queue_qos0_messages is enabled.
+		 */
+		valid_bytes = msgs->msg_bytes - db.config->max_inflight_bytes < db.config->max_queued_bytes;
+		valid_count = msgs->msg_count - msgs->inflight_maximum < db.config->max_queued_messages;
+
+		if(db.config->max_queued_messages == 0){
+			return valid_bytes;
+		}
+		if(db.config->max_queued_bytes == 0){
+			return valid_count;
+		}
+	}else{
 		valid_bytes = msgs->msg_bytes12 < db.config->max_inflight_bytes;
 		valid_count = msgs->inflight_quota > 0;
 
@@ -51,6 +67,7 @@ bool db__ready_for_flight(struct mosquitto_msg_data *msgs, int qos)
 		if(db.config->max_inflight_bytes == 0){
 			return valid_count;
 		}
+	}
 
 	return valid_bytes && valid_count;
 }
@@ -78,8 +95,7 @@ bool db__ready_for_queue(struct mosquitto *context, int qos, struct mosquitto_ms
 	}
 
 	if(qos == 0){
-		source_bytes = msg_data->msg_bytes;
+		return false; /* This case is handled in db__ready_for_flight() */
-		source_count = msg_data->msg_count;
 	}else{
 		source_bytes = msg_data->msg_bytes12;
 		source_count = msg_data->msg_count12;
@@ -427,7 +443,7 @@ int db__message_insert(struct mosquitto *context, uint16_t mid, enum mosquitto_m
 					return 1;
 				}
 			}
-		}else if(db__ready_for_queue(context, qos, msg_data)){
+		}else if(qos != 0 && db__ready_for_queue(context, qos, msg_data)){
 			state = mosq_ms_queued;
 			rc = 2;
 		}else{
@@ -529,7 +545,7 @@ int db__message_insert(struct mosquitto *context, uint16_t mid, enum mosquitto_m
 		util__decrement_send_quota(context);
 	}
 
-	if(dir == mosq_md_out && update && context->current_out_packet == NULL){
+	if(dir == mosq_md_out && update){
 		rc = db__message_write_inflight_out_latest(context);
 		if(rc) return rc;
 		rc = db__message_write_queued_out(context);

src/websockets.c

@@ -278,7 +278,6 @@ static int callback_mqtt(struct libwebsocket_context *context,
 			if(mosq->out_packet && !mosq->current_out_packet){
 				mosq->current_out_packet = mosq->out_packet;
 				mosq->out_packet = mosq->out_packet->next;
-				mosq->out_packet_len--;
 				if(!mosq->out_packet){
 					mosq->out_packet_last = NULL;
 				}
@@ -339,7 +338,6 @@ static int callback_mqtt(struct libwebsocket_context *context,
 				mosq->current_out_packet = mosq->out_packet;
 				if(mosq->out_packet){
 					mosq->out_packet = mosq->out_packet->next;
-					mosq->out_packet_len--;
 					if(!mosq->out_packet){
 						mosq->out_packet_last = NULL;
 					}