private static int SendPubrel(MqttClientConnection clientConnection, MqttMsgContext msgContext, MqttMsgBase msgInflight, int timeout)
{
// QoS 2, PUBREL message to send to broker, state change to wait PUBCOMP
if (msgContext.Flow == MqttMsgFlow.ToPublish)
{
msgContext.State = MqttMsgState.WaitForPubcomp;
msgContext.Timestamp = Environment.TickCount;
msgContext.Attempt++;
// retry ? set dup flag [v3.1.1] no needed
if (clientConnection.ProtocolVersion == MqttProtocolVersion.Version_3_1 && msgContext.Attempt > 1)
{
MqttOutgoingMessageManager.Pubrel(clientConnection, msgInflight.MessageId, true);
}
else
{
MqttOutgoingMessageManager.Pubrel(clientConnection, msgInflight.MessageId, false);
}
// update timeout : minimum between delay (based on current message sent) or current timeout
timeout = (clientConnection.Settings.DelayOnRetry < timeout) ? clientConnection.Settings.DelayOnRetry : timeout;
// re-enqueue message
clientConnection.EnqueueInflight(msgContext);
}
return(timeout);
}
private static MqttMsgBase WaitForPubrel(MqttClientConnection clientConnection, MqttMsgContext msgContext, MqttMsgBase msgInflight, ref bool msgReceivedProcessed)
{
// QoS 2, waiting for PUBREL of a PUBREC message sent
if (msgContext.Flow != MqttMsgFlow.ToAcknowledge)
{
return(null);
}
MqttMsgBase msgReceived;
if (!clientConnection.InternalQueue.TryPeek(out msgReceived))
{
return(null);
}
InternalEvent internalEvent;
// it is a PUBREL message
if ((msgReceived != null) && (msgReceived.Type == MqttMsgBase.MQTT_MSG_PUBREL_TYPE))
{
// PUBREL message for the current message, send PUBCOMP
if (msgReceived.MessageId == msgInflight.MessageId)
{
// received message processed
MqttMsgBase dequeuedMsg;
clientConnection.InternalQueue.TryDequeue(out dequeuedMsg);
msgReceivedProcessed = true;
MqttOutgoingMessageManager.Pubcomp(clientConnection, msgInflight.MessageId);
internalEvent = new MsgInternalEvent(msgInflight);
// notify published message from broker and acknowledged
clientConnection.EnqueueInternalEvent(internalEvent);
// PUBREL received (and PUBCOMP sent) for PUBLISH message with QoS Level 2, remove from session state
if ((msgInflight.Type == MqttMsgBase.MQTT_MSG_PUBLISH_TYPE) && (clientConnection.Session != null) &&
(clientConnection.Session.InflightMessages.ContainsKey(msgContext.Key)))
{
MqttMsgContext contextToBeRemoved;
clientConnection.Session.InflightMessages.TryRemove(msgContext.Key, out contextToBeRemoved);
}
}
else
{
// re-enqueue message
clientConnection.EnqueueInflight(msgContext);
}
}
else
{
// re-enqueue message
clientConnection.EnqueueInflight(msgContext);
}
return(msgReceived);
}
private static int HandleQueuedQos1SendSubscribeAndSendUnsubscribe(
MqttClientConnection clientConnection,
MqttMsgContext msgContext,
MqttMsgBase msgInflight,
int timeout)
{
InternalEvent internalEvent;
// QoS 1, PUBLISH or SUBSCRIBE/UNSUBSCRIBE message to send to broker, state change to wait PUBACK or SUBACK/UNSUBACK
if (msgContext.Flow == MqttMsgFlow.ToPublish)
{
msgContext.Timestamp = Environment.TickCount;
msgContext.Attempt++;
if (msgInflight.Type == MqttMsgBase.MQTT_MSG_PUBLISH_TYPE)
{
// PUBLISH message to send, wait for PUBACK
msgContext.State = MqttMsgState.WaitForPuback;
// retry ? set dup flag [v3.1.1] only for PUBLISH message
if (msgContext.Attempt > 1)
{
msgInflight.DupFlag = true;
}
}
else if (msgInflight.Type == MqttMsgBase.MQTT_MSG_SUBSCRIBE_TYPE)
{
// SUBSCRIBE message to send, wait for SUBACK
msgContext.State = MqttMsgState.WaitForSuback;
}
else if (msgInflight.Type == MqttMsgBase.MQTT_MSG_UNSUBSCRIBE_TYPE)
{
// UNSUBSCRIBE message to send, wait for UNSUBACK
msgContext.State = MqttMsgState.WaitForUnsuback;
}
MqttOutgoingMessageManager.Send(clientConnection, msgInflight);
// update timeout : minimum between delay (based on current message sent) or current timeout
timeout = (clientConnection.Settings.DelayOnRetry < timeout) ? clientConnection.Settings.DelayOnRetry : timeout;
// re-enqueue message (I have to re-analyze for receiving PUBACK, SUBACK or UNSUBACK)
clientConnection.EnqueueInflight(msgContext);
}
// QoS 1, PUBLISH message received from broker to acknowledge, send PUBACK
else if (msgContext.Flow == MqttMsgFlow.ToAcknowledge)
{
MqttOutgoingMessageManager.Puback(clientConnection, msgInflight.MessageId);
internalEvent = new MsgInternalEvent(msgInflight);
// notify published message from broker and acknowledged
clientConnection.EnqueueInternalEvent(internalEvent);
}
return(timeout);
}
private static void OnMqttMsgUnsubscribeReceived(MqttClientConnection clientConnection, ushort messageId, string[] topics)
{
for (int i = 0; i < topics.Length; i++)
{
// unsubscribe client for each topic requested
MqttSubscriberManager.Unsubscribe(topics[i], clientConnection);
}
// send UNSUBACK message to the client
MqttOutgoingMessageManager.Unsuback(clientConnection, messageId);
}
private static void HandleQueuedQos0(
MqttClientConnection clientConnection,
MqttMsgContext msgContext,
MqttMsgBase msgInflight)
{
// QoS 0, PUBLISH message to send to broker, no state change, no acknowledge
if (msgContext.Flow == MqttMsgFlow.ToPublish)
{
MqttOutgoingMessageManager.Send(clientConnection, msgInflight);
}
// QoS 0, no need acknowledge
else if (msgContext.Flow == MqttMsgFlow.ToAcknowledge)
{
var internalEvent = new MsgInternalEvent(msgInflight);
clientConnection.EnqueueInternalEvent(internalEvent);
}
}
private static int HandleQueuedQos2(
MqttClientConnection clientConnection,
MqttMsgContext msgContext,
MqttMsgBase msgInflight,
int timeout)
{
// QoS 2, PUBLISH message to send to broker, state change to wait PUBREC
if (msgContext.Flow == MqttMsgFlow.ToPublish)
{
msgContext.Timestamp = Environment.TickCount;
msgContext.Attempt++;
msgContext.State = MqttMsgState.WaitForPubrec;
// retry ? set dup flag
if (msgContext.Attempt > 1)
{
msgInflight.DupFlag = true;
}
MqttOutgoingMessageManager.Send(clientConnection, msgInflight);
// update timeout : minimum between delay (based on current message sent) or current timeout
timeout = (clientConnection.Settings.DelayOnRetry < timeout) ? clientConnection.Settings.DelayOnRetry : timeout;
// re-enqueue message (I have to re-analyze for receiving PUBREC)
clientConnection.EnqueueInflight(msgContext);
}
// QoS 2, PUBLISH message received from broker to acknowledge, send PUBREC, state change to wait PUBREL
else if (msgContext.Flow == MqttMsgFlow.ToAcknowledge)
{
msgContext.State = MqttMsgState.WaitForPubrel;
MqttOutgoingMessageManager.Pubrec(clientConnection, msgInflight.MessageId);
// re-enqueue message (I have to re-analyze for receiving PUBREL)
clientConnection.EnqueueInflight(msgContext);
}
return(timeout);
}
private static MqttMsgBase HandleWaitForPubrec(
MqttClientConnection clientConnection,
MqttMsgContext msgContext,
MqttMsgBase msgInflight,
ref bool msgReceivedProcessed,
ref int timeout)
{
// QoS 2, waiting for PUBREC of a PUBLISH message sent
if (msgContext.Flow != MqttMsgFlow.ToPublish)
{
return(null);
}
MqttMsgBase msgReceived;
if (!clientConnection.InternalQueue.TryPeek(out msgReceived))
{
return(null);
}
bool acknowledge = false;
InternalEvent internalEvent;
// it is a PUBREC message
if (msgReceived.Type == MqttMsgBase.MQTT_MSG_PUBREC_TYPE)
{
// PUBREC message for the current PUBLISH message, send PUBREL, wait for PUBCOMP
if (msgReceived.MessageId == msgInflight.MessageId)
{
// received message processed
MqttMsgBase dequeuedMsg;
clientConnection.InternalQueue.TryDequeue(out dequeuedMsg);
acknowledge = true;
msgReceivedProcessed = true;
MqttOutgoingMessageManager.Pubrel(clientConnection, msgInflight.MessageId, false);
msgContext.State = MqttMsgState.WaitForPubcomp;
msgContext.Timestamp = Environment.TickCount;
msgContext.Attempt = 1;
// update timeout : minimum between delay (based on current message sent) or current timeout
timeout = (clientConnection.Settings.DelayOnRetry < timeout)
? clientConnection.Settings.DelayOnRetry
: timeout;
// re-enqueue message
clientConnection.EnqueueInflight(msgContext);
}
}
// current message not acknowledged
if (!acknowledge)
{
var delta = Environment.TickCount - msgContext.Timestamp;
// check timeout for receiving PUBREC since PUBLISH was sent
if (delta >= clientConnection.Settings.DelayOnRetry)
{
// max retry not reached, resend
if (msgContext.Attempt < clientConnection.Settings.AttemptsOnRetry)
{
msgContext.State = MqttMsgState.QueuedQos2;
// re-enqueue message
clientConnection.EnqueueInflight(msgContext);
// update timeout (0 -> reanalyze queue immediately)
timeout = 0;
}
else
{
// PUBREC not received in time, PUBLISH retries failed, need to remove from session inflight messages too
if ((clientConnection.Session != null) &&
(clientConnection.Session.InflightMessages.ContainsKey(msgContext.Key)))
{
MqttMsgContext contextToBeRemoved;
clientConnection.Session.InflightMessages.TryRemove(msgContext.Key, out contextToBeRemoved);
}
// if PUBREC for a PUBLISH message not received after retries, raise event for not published
internalEvent = new MsgPublishedInternalEvent(msgInflight, false);
// notify not received acknowledge from broker and message not published
clientConnection.EnqueueInternalEvent(internalEvent);
}
}
else
{
// re-enqueue message
clientConnection.EnqueueInflight(msgContext);
// update timeout
int msgTimeout = (clientConnection.Settings.DelayOnRetry - delta);
timeout = (msgTimeout < timeout) ? msgTimeout : timeout;
}
}
return(msgReceived);
}
private static void EnqueueInternal(MqttClientConnection clientConnection, MqttMsgBase msg)
{
// enqueue is needed (or not)
bool enqueue = true;
// if it is a PUBREL message (for QoS Level 2)
if (msg.Type == MqttMsgBase.MQTT_MSG_PUBREL_TYPE)
{
// if it is a PUBREL but the corresponding PUBLISH isn't in the inflight queue,
// it means that we processed PUBLISH message and received PUBREL and we sent PUBCOMP
// but publisher didn't receive PUBCOMP so it re-sent PUBREL. We need only to re-send PUBCOMP.
// NOTE : I need to find on message id and flow because the broker could be publish/received
// to/from client and message id could be the same (one tracked by broker and the other by client)
MqttMsgContextFinder msgCtxFinder = new MqttMsgContextFinder(msg.MessageId, MqttMsgFlow.ToAcknowledge);
MqttMsgContext msgCtx = (MqttMsgContext)clientConnection.InflightQueue.FirstOrDefault(msgCtxFinder.Find);
// the PUBLISH message isn't in the inflight queue, it was already processed so
// we need to re-send PUBCOMP only
if (msgCtx == null)
{
MqttOutgoingMessageManager.Pubcomp(clientConnection, msg.MessageId);
enqueue = false;
}
}
// if it is a PUBCOMP message (for QoS Level 2)
else if (msg.Type == MqttMsgBase.MQTT_MSG_PUBCOMP_TYPE)
{
// if it is a PUBCOMP but the corresponding PUBLISH isn't in the inflight queue,
// it means that we sent PUBLISH message, sent PUBREL (after receiving PUBREC) and already received PUBCOMP
// but publisher didn't receive PUBREL so it re-sent PUBCOMP. We need only to ignore clientConnection PUBCOMP.
// NOTE : I need to find on message id and flow because the broker could be publish/received
// to/from client and message id could be the same (one tracked by broker and the other by client)
MqttMsgContextFinder msgCtxFinder = new MqttMsgContextFinder(msg.MessageId, MqttMsgFlow.ToPublish);
MqttMsgContext msgCtx = (MqttMsgContext)clientConnection.InflightQueue.FirstOrDefault(msgCtxFinder.Find);
// the PUBLISH message isn't in the inflight queue, it was already sent so we need to ignore clientConnection PUBCOMP
if (msgCtx == null)
{
enqueue = false;
}
}
// if it is a PUBREC message (for QoS Level 2)
else if (msg.Type == MqttMsgBase.MQTT_MSG_PUBREC_TYPE)
{
// if it is a PUBREC but the corresponding PUBLISH isn't in the inflight queue,
// it means that we sent PUBLISH message more times (retries) but broker didn't send PUBREC in time
// the publish is failed and we need only to ignore rawMessage.ClientConnection PUBREC.
// NOTE : I need to find on message id and flow because the broker could be publish/received
// to/from client and message id could be the same (one tracked by broker and the other by client)
MqttMsgContextFinder msgCtxFinder =
new MqttMsgContextFinder(msg.MessageId, MqttMsgFlow.ToPublish);
MqttMsgContext msgCtx = (MqttMsgContext)clientConnection.InflightQueue.FirstOrDefault(msgCtxFinder.Find);
// the PUBLISH message isn't in the inflight queue, it was already sent so we need to ignore rawMessage.ClientConnection PUBREC
if (msgCtx == null)
{
enqueue = false;
}
}
if (enqueue)
{
clientConnection.InternalQueue.Enqueue(msg);
}
}
public static void ProcessReceivedMessage(MqttRawMessage rawMessage)
{
if (!rawMessage.ClientConnection.IsRunning)
{
return;
}
// update last message received ticks
rawMessage.ClientConnection.LastCommunicationTime = Environment.TickCount;
// extract message type from received byte
byte msgType = (byte)((rawMessage.MessageType & MqttMsgBase.MSG_TYPE_MASK) >> MqttMsgBase.MSG_TYPE_OFFSET);
byte protocolVersion = (byte)rawMessage.ClientConnection.ProtocolVersion;
switch (msgType)
{
case MqttMsgBase.MQTT_MSG_CONNECT_TYPE:
MqttMsgConnect connect = MqttMsgConnect.Parse(rawMessage.MessageType, protocolVersion, rawMessage.PayloadBuffer);
rawMessage.ClientConnection.EnqueueInternalEvent(new MsgInternalEvent(connect));
break;
case MqttMsgBase.MQTT_MSG_PINGREQ_TYPE:
var pingReqest = MqttMsgPingReq.Parse(rawMessage.MessageType, protocolVersion);
MqttOutgoingMessageManager.PingResp(rawMessage.ClientConnection);
break;
case MqttMsgBase.MQTT_MSG_SUBSCRIBE_TYPE:
MqttMsgSubscribe subscribe = MqttMsgSubscribe.Parse(rawMessage.MessageType, protocolVersion, rawMessage.PayloadBuffer, rawMessage.PayloadLength);
rawMessage.ClientConnection.EnqueueInternalEvent(new MsgInternalEvent(subscribe));
break;
case MqttMsgBase.MQTT_MSG_PUBLISH_TYPE:
MqttMsgPublish publish = MqttMsgPublish.Parse(rawMessage.MessageType, protocolVersion, rawMessage.PayloadBuffer, rawMessage.PayloadLength);
EnqueueInflight(rawMessage.ClientConnection, publish, MqttMsgFlow.ToAcknowledge);
break;
case MqttMsgBase.MQTT_MSG_PUBACK_TYPE:
// enqueue PUBACK message received (for QoS Level 1) into the internal queue
MqttMsgPuback puback = MqttMsgPuback.Parse(rawMessage.MessageType, protocolVersion, rawMessage.PayloadBuffer);
EnqueueInternal(rawMessage.ClientConnection, puback);
break;
case MqttMsgBase.MQTT_MSG_PUBREC_TYPE:
// enqueue PUBREC message received (for QoS Level 2) into the internal queue
MqttMsgPubrec pubrec = MqttMsgPubrec.Parse(rawMessage.MessageType, protocolVersion, rawMessage.PayloadBuffer);
EnqueueInternal(rawMessage.ClientConnection, pubrec);
break;
case MqttMsgBase.MQTT_MSG_PUBREL_TYPE:
// enqueue PUBREL message received (for QoS Level 2) into the internal queue
MqttMsgPubrel pubrel = MqttMsgPubrel.Parse(rawMessage.MessageType, protocolVersion, rawMessage.PayloadBuffer);
EnqueueInternal(rawMessage.ClientConnection, pubrel);
break;
case MqttMsgBase.MQTT_MSG_PUBCOMP_TYPE:
// enqueue PUBCOMP message received (for QoS Level 2) into the internal queue
MqttMsgPubcomp pubcomp = MqttMsgPubcomp.Parse(rawMessage.MessageType, protocolVersion, rawMessage.PayloadBuffer);
EnqueueInternal(rawMessage.ClientConnection, pubcomp);
break;
case MqttMsgBase.MQTT_MSG_UNSUBSCRIBE_TYPE:
MqttMsgUnsubscribe unsubscribe = MqttMsgUnsubscribe.Parse(rawMessage.MessageType, protocolVersion, rawMessage.PayloadBuffer, rawMessage.PayloadLength);
rawMessage.ClientConnection.EnqueueInternalEvent(new MsgInternalEvent(unsubscribe));
break;
case MqttMsgBase.MQTT_MSG_DISCONNECT_TYPE:
MqttMsgDisconnect disconnect = MqttMsgDisconnect.Parse(rawMessage.MessageType, protocolVersion);
rawMessage.ClientConnection.EnqueueInternalEvent(new MsgInternalEvent(disconnect));
break;
case MqttMsgBase.MQTT_MSG_CONNACK_TYPE:
case MqttMsgBase.MQTT_MSG_PINGRESP_TYPE:
case MqttMsgBase.MQTT_MSG_SUBACK_TYPE:
case MqttMsgBase.MQTT_MSG_UNSUBACK_TYPE:
throw new MqttClientException(MqttClientErrorCode.WrongBrokerMessage);
default:
throw new MqttClientException(MqttClientErrorCode.WrongBrokerMessage);
}
}
